fs/ext4/extents.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   4  * Written by Alex Tomas <alex@clusterfs.com>
   5  *
   6  * Architecture independence:
   7  *   Copyright (c) 2005, Bull S.A.
   8  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   9  */
  10
  11 /*
  12  * Extents support for EXT4
  13  *
  14  * TODO:
  15  *   - ext4*_error() should be used in some situations
  16  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  17  *   - smart tree reduction
  18  */
  19
  20 #include <linux/fs.h>
  21 #include <linux/time.h>
  22 #include <linux/jbd2.h>
  23 #include <linux/highuid.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/quotaops.h>
  26 #include <linux/string.h>
  27 #include <linux/slab.h>
  28 #include <linux/uaccess.h>
  29 #include <linux/fiemap.h>
  30 #include <linux/backing-dev.h>
  31 #include <linux/iomap.h>
  32 #include "ext4_jbd2.h"
  33 #include "ext4_extents.h"
  34 #include "xattr.h"
  35
  36 #include <trace/events/ext4.h>
  37
  38 /*
  39  * used by extent splitting.
  40  */
  41 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  42                                         due to ENOSPC */
  43 #define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  44 #define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  45
  46 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  47 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  48
  49 static __le32 ext4_extent_block_csum(struct inode *inode,
  50                                      struct ext4_extent_header *eh)
  51 {
  52         struct ext4_inode_info *ei = EXT4_I(inode);
  53         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  54         __u32 csum;
  55
  56         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  57                            EXT4_EXTENT_TAIL_OFFSET(eh));
  58         return cpu_to_le32(csum);
  59 }
  60
  61 static int ext4_extent_block_csum_verify(struct inode *inode,
  62                                          struct ext4_extent_header *eh)
  63 {
  64         struct ext4_extent_tail *et;
  65
  66         if (!ext4_has_metadata_csum(inode->i_sb))
  67                 return 1;
  68
  69         et = find_ext4_extent_tail(eh);
  70         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  71                 return 0;
  72         return 1;
  73 }
  74
  75 static void ext4_extent_block_csum_set(struct inode *inode,
  76                                        struct ext4_extent_header *eh)
  77 {
  78         struct ext4_extent_tail *et;
  79
  80         if (!ext4_has_metadata_csum(inode->i_sb))
  81                 return;
  82
  83         et = find_ext4_extent_tail(eh);
  84         et->et_checksum = ext4_extent_block_csum(inode, eh);
  85 }
  86
  87 static int ext4_split_extent_at(handle_t *handle,
  88                              struct inode *inode,
  89                              struct ext4_ext_path **ppath,
  90                              ext4_lblk_t split,
  91                              int split_flag,
  92                              int flags);
  93
  94 static int ext4_ext_trunc_restart_fn(struct inode *inode, int *dropped)
  95 {
  96         /*
  97          * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
  98          * moment, get_block can be called only for blocks inside i_size since
  99          * page cache has been already dropped and writes are blocked by
 100          * i_mutex. So we can safely drop the i_data_sem here.
 101          */
 102         BUG_ON(EXT4_JOURNAL(inode) == NULL);
 103         ext4_discard_preallocations(inode, 0);
 104         up_write(&EXT4_I(inode)->i_data_sem);
 105         *dropped = 1;
 106         return 0;
 107 }
 108
 109 /*
 110  * Make sure 'handle' has at least 'check_cred' credits. If not, restart
 111  * transaction with 'restart_cred' credits. The function drops i_data_sem
 112  * when restarting transaction and gets it after transaction is restarted.
 113  *
 114  * The function returns 0 on success, 1 if transaction had to be restarted,
 115  * and < 0 in case of fatal error.
 116  */
 117 int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,
 118                                 int check_cred, int restart_cred,
 119                                 int revoke_cred)
 120 {
 121         int ret;
 122         int dropped = 0;
 123
 124         ret = ext4_journal_ensure_credits_fn(handle, check_cred, restart_cred,
 125                 revoke_cred, ext4_ext_trunc_restart_fn(inode, &dropped));
 126         if (dropped)
 127                 down_write(&EXT4_I(inode)->i_data_sem);
 128         return ret;
 129 }
 130
 131 /*
 132  * could return:
 133  *  - EROFS
 134  *  - ENOMEM
 135  */
 136 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 137                                 struct ext4_ext_path *path)
 138 {
 139         if (path->p_bh) {
 140                 /* path points to block */
 141                 BUFFER_TRACE(path->p_bh, "get_write_access");
 142                 return ext4_journal_get_write_access(handle, path->p_bh);
 143         }
 144         /* path points to leaf/index in inode body */
 145         /* we use in-core data, no need to protect them */
 146         return 0;
 147 }
 148
 149 /*
 150  * could return:
 151  *  - EROFS
 152  *  - ENOMEM
 153  *  - EIO
 154  */
 155 static int __ext4_ext_dirty(const char *where, unsigned int line,
 156                             handle_t *handle, struct inode *inode,
 157                             struct ext4_ext_path *path)
 158 {
 159         int err;
 160
 161         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 162         if (path->p_bh) {
 163                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 164                 /* path points to block */
 165                 err = __ext4_handle_dirty_metadata(where, line, handle,
 166                                                    inode, path->p_bh);
 167         } else {
 168                 /* path points to leaf/index in inode body */
 169                 err = ext4_mark_inode_dirty(handle, inode);
 170         }
 171         return err;
 172 }
 173
 174 #define ext4_ext_dirty(handle, inode, path) \
 175                 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
 176
 177 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 178                               struct ext4_ext_path *path,
 179                               ext4_lblk_t block)
 180 {
 181         if (path) {
 182                 int depth = path->p_depth;
 183                 struct ext4_extent *ex;
 184
 185                 /*
 186                  * Try to predict block placement assuming that we are
 187                  * filling in a file which will eventually be
 188                  * non-sparse --- i.e., in the case of libbfd writing
 189                  * an ELF object sections out-of-order but in a way
 190                  * the eventually results in a contiguous object or
 191                  * executable file, or some database extending a table
 192                  * space file.  However, this is actually somewhat
 193                  * non-ideal if we are writing a sparse file such as
 194                  * qemu or KVM writing a raw image file that is going
 195                  * to stay fairly sparse, since it will end up
 196                  * fragmenting the file system's free space.  Maybe we
 197                  * should have some hueristics or some way to allow
 198                  * userspace to pass a hint to file system,
 199                  * especially if the latter case turns out to be
 200                  * common.
 201                  */
 202                 ex = path[depth].p_ext;
 203                 if (ex) {
 204                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 205                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 206
 207                         if (block > ext_block)
 208                                 return ext_pblk + (block - ext_block);
 209                         else
 210                                 return ext_pblk - (ext_block - block);
 211                 }
 212
 213                 /* it looks like index is empty;
 214                  * try to find starting block from index itself */
 215                 if (path[depth].p_bh)
 216                         return path[depth].p_bh->b_blocknr;
 217         }
 218
 219         /* OK. use inode's group */
 220         return ext4_inode_to_goal_block(inode);
 221 }
 222
 223 /*
 224  * Allocation for a meta data block
 225  */
 226 static ext4_fsblk_t
 227 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 228                         struct ext4_ext_path *path,
 229                         struct ext4_extent *ex, int *err, unsigned int flags)
 230 {
 231         ext4_fsblk_t goal, newblock;
 232
 233         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 234         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 235                                         NULL, err);
 236         return newblock;
 237 }
 238
 239 static inline int ext4_ext_space_block(struct inode *inode, int check)
 240 {
 241         int size;
 242
 243         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 244                         / sizeof(struct ext4_extent);
 245 #ifdef AGGRESSIVE_TEST
 246         if (!check && size > 6)
 247                 size = 6;
 248 #endif
 249         return size;
 250 }
 251
 252 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 253 {
 254         int size;
 255
 256         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 257                         / sizeof(struct ext4_extent_idx);
 258 #ifdef AGGRESSIVE_TEST
 259         if (!check && size > 5)
 260                 size = 5;
 261 #endif
 262         return size;
 263 }
 264
 265 static inline int ext4_ext_space_root(struct inode *inode, int check)
 266 {
 267         int size;
 268
 269         size = sizeof(EXT4_I(inode)->i_data);
 270         size -= sizeof(struct ext4_extent_header);
 271         size /= sizeof(struct ext4_extent);
 272 #ifdef AGGRESSIVE_TEST
 273         if (!check && size > 3)
 274                 size = 3;
 275 #endif
 276         return size;
 277 }
 278
 279 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 280 {
 281         int size;
 282
 283         size = sizeof(EXT4_I(inode)->i_data);
 284         size -= sizeof(struct ext4_extent_header);
 285         size /= sizeof(struct ext4_extent_idx);
 286 #ifdef AGGRESSIVE_TEST
 287         if (!check && size > 4)
 288                 size = 4;
 289 #endif
 290         return size;
 291 }
 292
 293 static inline int
 294 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 295                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 296                            int nofail)
 297 {
 298         struct ext4_ext_path *path = *ppath;
 299         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 300         int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO;
 301
 302         if (nofail)
 303                 flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL;
 304
 305         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 306                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 307                         flags);
 308 }
 309
 310 static int
 311 ext4_ext_max_entries(struct inode *inode, int depth)
 312 {
 313         int max;
 314
 315         if (depth == ext_depth(inode)) {
 316                 if (depth == 0)
 317                         max = ext4_ext_space_root(inode, 1);
 318                 else
 319                         max = ext4_ext_space_root_idx(inode, 1);
 320         } else {
 321                 if (depth == 0)
 322                         max = ext4_ext_space_block(inode, 1);
 323                 else
 324                         max = ext4_ext_space_block_idx(inode, 1);
 325         }
 326
 327         return max;
 328 }
 329
 330 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 331 {
 332         ext4_fsblk_t block = ext4_ext_pblock(ext);
 333         int len = ext4_ext_get_actual_len(ext);
 334         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 335
 336         /*
 337          * We allow neither:
 338          *  - zero length
 339          *  - overflow/wrap-around
 340          */
 341         if (lblock + len <= lblock)
 342                 return 0;
 343         return ext4_inode_block_valid(inode, block, len);
 344 }
 345
 346 static int ext4_valid_extent_idx(struct inode *inode,
 347                                 struct ext4_extent_idx *ext_idx)
 348 {
 349         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 350
 351         return ext4_inode_block_valid(inode, block, 1);
 352 }
 353
 354 static int ext4_valid_extent_entries(struct inode *inode,
 355                                      struct ext4_extent_header *eh,
 356                                      ext4_fsblk_t *pblk, int depth)
 357 {
 358         unsigned short entries;
 359         if (eh->eh_entries == 0)
 360                 return 1;
 361
 362         entries = le16_to_cpu(eh->eh_entries);
 363
 364         if (depth == 0) {
 365                 /* leaf entries */
 366                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 367                 ext4_lblk_t lblock = 0;
 368                 ext4_lblk_t prev = 0;
 369                 int len = 0;
 370                 while (entries) {
 371                         if (!ext4_valid_extent(inode, ext))
 372                                 return 0;
 373
 374                         /* Check for overlapping extents */
 375                         lblock = le32_to_cpu(ext->ee_block);
 376                         len = ext4_ext_get_actual_len(ext);
 377                         if ((lblock <= prev) && prev) {
 378                                 *pblk = ext4_ext_pblock(ext);
 379                                 return 0;
 380                         }
 381                         ext++;
 382                         entries--;
 383                         prev = lblock + len - 1;
 384                 }
 385         } else {
 386                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 387                 while (entries) {
 388                         if (!ext4_valid_extent_idx(inode, ext_idx))
 389                                 return 0;
 390                         ext_idx++;
 391                         entries--;
 392                 }
 393         }
 394         return 1;
 395 }
 396
 397 static int __ext4_ext_check(const char *function, unsigned int line,
 398                             struct inode *inode, struct ext4_extent_header *eh,
 399                             int depth, ext4_fsblk_t pblk)
 400 {
 401         const char *error_msg;
 402         int max = 0, err = -EFSCORRUPTED;
 403
 404         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 405                 error_msg = "invalid magic";
 406                 goto corrupted;
 407         }
 408         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 409                 error_msg = "unexpected eh_depth";
 410                 goto corrupted;
 411         }
 412         if (unlikely(eh->eh_max == 0)) {
 413                 error_msg = "invalid eh_max";
 414                 goto corrupted;
 415         }
 416         max = ext4_ext_max_entries(inode, depth);
 417         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 418                 error_msg = "too large eh_max";
 419                 goto corrupted;
 420         }
 421         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 422                 error_msg = "invalid eh_entries";
 423                 goto corrupted;
 424         }
 425         if (!ext4_valid_extent_entries(inode, eh, &pblk, depth)) {
 426                 error_msg = "invalid extent entries";
 427                 goto corrupted;
 428         }
 429         if (unlikely(depth > 32)) {
 430                 error_msg = "too large eh_depth";
 431                 goto corrupted;
 432         }
 433         /* Verify checksum on non-root extent tree nodes */
 434         if (ext_depth(inode) != depth &&
 435             !ext4_extent_block_csum_verify(inode, eh)) {
 436                 error_msg = "extent tree corrupted";
 437                 err = -EFSBADCRC;
 438                 goto corrupted;
 439         }
 440         return 0;
 441
 442 corrupted:
 443         ext4_error_inode_err(inode, function, line, 0, -err,
 444                              "pblk %llu bad header/extent: %s - magic %x, "
 445                              "entries %u, max %u(%u), depth %u(%u)",
 446                              (unsigned long long) pblk, error_msg,
 447                              le16_to_cpu(eh->eh_magic),
 448                              le16_to_cpu(eh->eh_entries),
 449                              le16_to_cpu(eh->eh_max),
 450                              max, le16_to_cpu(eh->eh_depth), depth);
 451         return err;
 452 }
 453
 454 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 455         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 456
 457 int ext4_ext_check_inode(struct inode *inode)
 458 {
 459         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 460 }
 461
 462 static void ext4_cache_extents(struct inode *inode,
 463                                struct ext4_extent_header *eh)
 464 {
 465         struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 466         ext4_lblk_t prev = 0;
 467         int i;
 468
 469         for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 470                 unsigned int status = EXTENT_STATUS_WRITTEN;
 471                 ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 472                 int len = ext4_ext_get_actual_len(ex);
 473
 474                 if (prev && (prev != lblk))
 475                         ext4_es_cache_extent(inode, prev, lblk - prev, ~0,
 476                                              EXTENT_STATUS_HOLE);
 477
 478                 if (ext4_ext_is_unwritten(ex))
 479                         status = EXTENT_STATUS_UNWRITTEN;
 480                 ext4_es_cache_extent(inode, lblk, len,
 481                                      ext4_ext_pblock(ex), status);
 482                 prev = lblk + len;
 483         }
 484 }
 485
 486 static struct buffer_head *
 487 __read_extent_tree_block(const char *function, unsigned int line,
 488                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 489                          int flags)
 490 {
 491         struct buffer_head              *bh;
 492         int                             err;
 493         gfp_t                           gfp_flags = __GFP_MOVABLE | GFP_NOFS;
 494
 495         if (flags & EXT4_EX_NOFAIL)
 496                 gfp_flags |= __GFP_NOFAIL;
 497
 498         bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);
 499         if (unlikely(!bh))
 500                 return ERR_PTR(-ENOMEM);
 501
 502         if (!bh_uptodate_or_lock(bh)) {
 503                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 504                 err = ext4_read_bh(bh, 0, NULL);
 505                 if (err < 0)
 506                         goto errout;
 507         }
 508         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 509                 return bh;
 510         err = __ext4_ext_check(function, line, inode,
 511                                ext_block_hdr(bh), depth, pblk);
 512         if (err)
 513                 goto errout;
 514         set_buffer_verified(bh);
 515         /*
 516          * If this is a leaf block, cache all of its entries
 517          */
 518         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 519                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 520                 ext4_cache_extents(inode, eh);
 521         }
 522         return bh;
 523 errout:
 524         put_bh(bh);
 525         return ERR_PTR(err);
 526
 527 }
 528
 529 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 530         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 531                                  (depth), (flags))
 532
 533 /*
 534  * This function is called to cache a file's extent information in the
 535  * extent status tree
 536  */
 537 int ext4_ext_precache(struct inode *inode)
 538 {
 539         struct ext4_inode_info *ei = EXT4_I(inode);
 540         struct ext4_ext_path *path = NULL;
 541         struct buffer_head *bh;
 542         int i = 0, depth, ret = 0;
 543
 544         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 545                 return 0;       /* not an extent-mapped inode */
 546
 547         down_read(&ei->i_data_sem);
 548         depth = ext_depth(inode);
 549
 550         /* Don't cache anything if there are no external extent blocks */
 551         if (!depth) {
 552                 up_read(&ei->i_data_sem);
 553                 return ret;
 554         }
 555
 556         path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
 557                        GFP_NOFS);
 558         if (path == NULL) {
 559                 up_read(&ei->i_data_sem);
 560                 return -ENOMEM;
 561         }
 562
 563         path[0].p_hdr = ext_inode_hdr(inode);
 564         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 565         if (ret)
 566                 goto out;
 567         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 568         while (i >= 0) {
 569                 /*
 570                  * If this is a leaf block or we've reached the end of
 571                  * the index block, go up
 572                  */
 573                 if ((i == depth) ||
 574                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 575                         brelse(path[i].p_bh);
 576                         path[i].p_bh = NULL;
 577                         i--;
 578                         continue;
 579                 }
 580                 bh = read_extent_tree_block(inode,
 581                                             ext4_idx_pblock(path[i].p_idx++),
 582                                             depth - i - 1,
 583                                             EXT4_EX_FORCE_CACHE);
 584                 if (IS_ERR(bh)) {
 585                         ret = PTR_ERR(bh);
 586                         break;
 587                 }
 588                 i++;
 589                 path[i].p_bh = bh;
 590                 path[i].p_hdr = ext_block_hdr(bh);
 591                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 592         }
 593         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 594 out:
 595         up_read(&ei->i_data_sem);
 596         ext4_ext_drop_refs(path);
 597         kfree(path);
 598         return ret;
 599 }
 600
 601 #ifdef EXT_DEBUG
 602 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 603 {
 604         int k, l = path->p_depth;
 605
 606         ext_debug(inode, "path:");
 607         for (k = 0; k <= l; k++, path++) {
 608                 if (path->p_idx) {
 609                         ext_debug(inode, "  %d->%llu",
 610                                   le32_to_cpu(path->p_idx->ei_block),
 611                                   ext4_idx_pblock(path->p_idx));
 612                 } else if (path->p_ext) {
 613                         ext_debug(inode, "  %d:[%d]%d:%llu ",
 614                                   le32_to_cpu(path->p_ext->ee_block),
 615                                   ext4_ext_is_unwritten(path->p_ext),
 616                                   ext4_ext_get_actual_len(path->p_ext),
 617                                   ext4_ext_pblock(path->p_ext));
 618                 } else
 619                         ext_debug(inode, "  []");
 620         }
 621         ext_debug(inode, "\n");
 622 }
 623
 624 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 625 {
 626         int depth = ext_depth(inode);
 627         struct ext4_extent_header *eh;
 628         struct ext4_extent *ex;
 629         int i;
 630
 631         if (!path)
 632                 return;
 633
 634         eh = path[depth].p_hdr;
 635         ex = EXT_FIRST_EXTENT(eh);
 636
 637         ext_debug(inode, "Displaying leaf extents\n");
 638
 639         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 640                 ext_debug(inode, "%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 641                           ext4_ext_is_unwritten(ex),
 642                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 643         }
 644         ext_debug(inode, "\n");
 645 }
 646
 647 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 648                         ext4_fsblk_t newblock, int level)
 649 {
 650         int depth = ext_depth(inode);
 651         struct ext4_extent *ex;
 652
 653         if (depth != level) {
 654                 struct ext4_extent_idx *idx;
 655                 idx = path[level].p_idx;
 656                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 657                         ext_debug(inode, "%d: move %d:%llu in new index %llu\n",
 658                                   level, le32_to_cpu(idx->ei_block),
 659                                   ext4_idx_pblock(idx), newblock);
 660                         idx++;
 661                 }
 662
 663                 return;
 664         }
 665
 666         ex = path[depth].p_ext;
 667         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 668                 ext_debug(inode, "move %d:%llu:[%d]%d in new leaf %llu\n",
 669                                 le32_to_cpu(ex->ee_block),
 670                                 ext4_ext_pblock(ex),
 671                                 ext4_ext_is_unwritten(ex),
 672                                 ext4_ext_get_actual_len(ex),
 673                                 newblock);
 674                 ex++;
 675         }
 676 }
 677
 678 #else
 679 #define ext4_ext_show_path(inode, path)
 680 #define ext4_ext_show_leaf(inode, path)
 681 #define ext4_ext_show_move(inode, path, newblock, level)
 682 #endif
 683
 684 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 685 {
 686         int depth, i;
 687
 688         if (!path)
 689                 return;
 690         depth = path->p_depth;
 691         for (i = 0; i <= depth; i++, path++) {
 692                 brelse(path->p_bh);
 693                 path->p_bh = NULL;
 694         }
 695 }
 696
 697 /*
 698  * ext4_ext_binsearch_idx:
 699  * binary search for the closest index of the given block
 700  * the header must be checked before calling this
 701  */
 702 static void
 703 ext4_ext_binsearch_idx(struct inode *inode,
 704                         struct ext4_ext_path *path, ext4_lblk_t block)
 705 {
 706         struct ext4_extent_header *eh = path->p_hdr;
 707         struct ext4_extent_idx *r, *l, *m;
 708
 709
 710         ext_debug(inode, "binsearch for %u(idx):  ", block);
 711
 712         l = EXT_FIRST_INDEX(eh) + 1;
 713         r = EXT_LAST_INDEX(eh);
 714         while (l <= r) {
 715                 m = l + (r - l) / 2;
 716                 if (block < le32_to_cpu(m->ei_block))
 717                         r = m - 1;
 718                 else
 719                         l = m + 1;
 720                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 721                           le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block),
 722                           r, le32_to_cpu(r->ei_block));
 723         }
 724
 725         path->p_idx = l - 1;
 726         ext_debug(inode, "  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 727                   ext4_idx_pblock(path->p_idx));
 728
 729 #ifdef CHECK_BINSEARCH
 730         {
 731                 struct ext4_extent_idx *chix, *ix;
 732                 int k;
 733
 734                 chix = ix = EXT_FIRST_INDEX(eh);
 735                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 736                         if (k != 0 && le32_to_cpu(ix->ei_block) <=
 737                             le32_to_cpu(ix[-1].ei_block)) {
 738                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 739                                        "first=0x%p\n", k,
 740                                        ix, EXT_FIRST_INDEX(eh));
 741                                 printk(KERN_DEBUG "%u <= %u\n",
 742                                        le32_to_cpu(ix->ei_block),
 743                                        le32_to_cpu(ix[-1].ei_block));
 744                         }
 745                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 746                                            <= le32_to_cpu(ix[-1].ei_block));
 747                         if (block < le32_to_cpu(ix->ei_block))
 748                                 break;
 749                         chix = ix;
 750                 }
 751                 BUG_ON(chix != path->p_idx);
 752         }
 753 #endif
 754
 755 }
 756
 757 /*
 758  * ext4_ext_binsearch:
 759  * binary search for closest extent of the given block
 760  * the header must be checked before calling this
 761  */
 762 static void
 763 ext4_ext_binsearch(struct inode *inode,
 764                 struct ext4_ext_path *path, ext4_lblk_t block)
 765 {
 766         struct ext4_extent_header *eh = path->p_hdr;
 767         struct ext4_extent *r, *l, *m;
 768
 769         if (eh->eh_entries == 0) {
 770                 /*
 771                  * this leaf is empty:
 772                  * we get such a leaf in split/add case
 773                  */
 774                 return;
 775         }
 776
 777         ext_debug(inode, "binsearch for %u:  ", block);
 778
 779         l = EXT_FIRST_EXTENT(eh) + 1;
 780         r = EXT_LAST_EXTENT(eh);
 781
 782         while (l <= r) {
 783                 m = l + (r - l) / 2;
 784                 if (block < le32_to_cpu(m->ee_block))
 785                         r = m - 1;
 786                 else
 787                         l = m + 1;
 788                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 789                           le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block),
 790                           r, le32_to_cpu(r->ee_block));
 791         }
 792
 793         path->p_ext = l - 1;
 794         ext_debug(inode, "  -> %d:%llu:[%d]%d ",
 795                         le32_to_cpu(path->p_ext->ee_block),
 796                         ext4_ext_pblock(path->p_ext),
 797                         ext4_ext_is_unwritten(path->p_ext),
 798                         ext4_ext_get_actual_len(path->p_ext));
 799
 800 #ifdef CHECK_BINSEARCH
 801         {
 802                 struct ext4_extent *chex, *ex;
 803                 int k;
 804
 805                 chex = ex = EXT_FIRST_EXTENT(eh);
 806                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 807                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 808                                           <= le32_to_cpu(ex[-1].ee_block));
 809                         if (block < le32_to_cpu(ex->ee_block))
 810                                 break;
 811                         chex = ex;
 812                 }
 813                 BUG_ON(chex != path->p_ext);
 814         }
 815 #endif
 816
 817 }
 818
 819 void ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 820 {
 821         struct ext4_extent_header *eh;
 822
 823         eh = ext_inode_hdr(inode);
 824         eh->eh_depth = 0;
 825         eh->eh_entries = 0;
 826         eh->eh_magic = EXT4_EXT_MAGIC;
 827         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 828         ext4_mark_inode_dirty(handle, inode);
 829 }
 830
 831 struct ext4_ext_path *
 832 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 833                  struct ext4_ext_path **orig_path, int flags)
 834 {
 835         struct ext4_extent_header *eh;
 836         struct buffer_head *bh;
 837         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 838         short int depth, i, ppos = 0;
 839         int ret;
 840         gfp_t gfp_flags = GFP_NOFS;
 841
 842         if (flags & EXT4_EX_NOFAIL)
 843                 gfp_flags |= __GFP_NOFAIL;
 844
 845         eh = ext_inode_hdr(inode);
 846         depth = ext_depth(inode);
 847         if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
 848                 EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
 849                                  depth);
 850                 ret = -EFSCORRUPTED;
 851                 goto err;
 852         }
 853
 854         if (path) {
 855                 ext4_ext_drop_refs(path);
 856                 if (depth > path[0].p_maxdepth) {
 857                         kfree(path);
 858                         *orig_path = path = NULL;
 859                 }
 860         }
 861         if (!path) {
 862                 /* account possible depth increase */
 863                 path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
 864                                 gfp_flags);
 865                 if (unlikely(!path))
 866                         return ERR_PTR(-ENOMEM);
 867                 path[0].p_maxdepth = depth + 1;
 868         }
 869         path[0].p_hdr = eh;
 870         path[0].p_bh = NULL;
 871
 872         i = depth;
 873         if (!(flags & EXT4_EX_NOCACHE) && depth == 0)
 874                 ext4_cache_extents(inode, eh);
 875         /* walk through the tree */
 876         while (i) {
 877                 ext_debug(inode, "depth %d: num %d, max %d\n",
 878                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 879
 880                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 881                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 882                 path[ppos].p_depth = i;
 883                 path[ppos].p_ext = NULL;
 884
 885                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 886                                             flags);
 887                 if (IS_ERR(bh)) {
 888                         ret = PTR_ERR(bh);
 889                         goto err;
 890                 }
 891
 892                 eh = ext_block_hdr(bh);
 893                 ppos++;
 894                 path[ppos].p_bh = bh;
 895                 path[ppos].p_hdr = eh;
 896         }
 897
 898         path[ppos].p_depth = i;
 899         path[ppos].p_ext = NULL;
 900         path[ppos].p_idx = NULL;
 901
 902         /* find extent */
 903         ext4_ext_binsearch(inode, path + ppos, block);
 904         /* if not an empty leaf */
 905         if (path[ppos].p_ext)
 906                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 907
 908         ext4_ext_show_path(inode, path);
 909
 910         return path;
 911
 912 err:
 913         ext4_ext_drop_refs(path);
 914         kfree(path);
 915         if (orig_path)
 916                 *orig_path = NULL;
 917         return ERR_PTR(ret);
 918 }
 919
 920 /*
 921  * ext4_ext_insert_index:
 922  * insert new index [@logical;@ptr] into the block at @curp;
 923  * check where to insert: before @curp or after @curp
 924  */
 925 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 926                                  struct ext4_ext_path *curp,
 927                                  int logical, ext4_fsblk_t ptr)
 928 {
 929         struct ext4_extent_idx *ix;
 930         int len, err;
 931
 932         err = ext4_ext_get_access(handle, inode, curp);
 933         if (err)
 934                 return err;
 935
 936         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 937                 EXT4_ERROR_INODE(inode,
 938                                  "logical %d == ei_block %d!",
 939                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 940                 return -EFSCORRUPTED;
 941         }
 942
 943         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 944                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 945                 EXT4_ERROR_INODE(inode,
 946                                  "eh_entries %d >= eh_max %d!",
 947                                  le16_to_cpu(curp->p_hdr->eh_entries),
 948                                  le16_to_cpu(curp->p_hdr->eh_max));
 949                 return -EFSCORRUPTED;
 950         }
 951
 952         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 953                 /* insert after */
 954                 ext_debug(inode, "insert new index %d after: %llu\n",
 955                           logical, ptr);
 956                 ix = curp->p_idx + 1;
 957         } else {
 958                 /* insert before */
 959                 ext_debug(inode, "insert new index %d before: %llu\n",
 960                           logical, ptr);
 961                 ix = curp->p_idx;
 962         }
 963
 964         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 965         BUG_ON(len < 0);
 966         if (len > 0) {
 967                 ext_debug(inode, "insert new index %d: "
 968                                 "move %d indices from 0x%p to 0x%p\n",
 969                                 logical, len, ix, ix + 1);
 970                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 971         }
 972
 973         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 974                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 975                 return -EFSCORRUPTED;
 976         }
 977
 978         ix->ei_block = cpu_to_le32(logical);
 979         ext4_idx_store_pblock(ix, ptr);
 980         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 981
 982         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 983                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 984                 return -EFSCORRUPTED;
 985         }
 986
 987         err = ext4_ext_dirty(handle, inode, curp);
 988         ext4_std_error(inode->i_sb, err);
 989
 990         return err;
 991 }
 992
 993 /*
 994  * ext4_ext_split:
 995  * inserts new subtree into the path, using free index entry
 996  * at depth @at:
 997  * - allocates all needed blocks (new leaf and all intermediate index blocks)
 998  * - makes decision where to split
 999  * - moves remaining extents and index entries (right to the split point)
1000  *   into the newly allocated blocks
1001  * - initializes subtree
1002  */
1003 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1004                           unsigned int flags,
1005                           struct ext4_ext_path *path,
1006                           struct ext4_extent *newext, int at)
1007 {
1008         struct buffer_head *bh = NULL;
1009         int depth = ext_depth(inode);
1010         struct ext4_extent_header *neh;
1011         struct ext4_extent_idx *fidx;
1012         int i = at, k, m, a;
1013         ext4_fsblk_t newblock, oldblock;
1014         __le32 border;
1015         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1016         gfp_t gfp_flags = GFP_NOFS;
1017         int err = 0;
1018         size_t ext_size = 0;
1019
1020         if (flags & EXT4_EX_NOFAIL)
1021                 gfp_flags |= __GFP_NOFAIL;
1022
1023         /* make decision: where to split? */
1024         /* FIXME: now decision is simplest: at current extent */
1025
1026         /* if current leaf will be split, then we should use
1027          * border from split point */
1028         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1029                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1030                 return -EFSCORRUPTED;
1031         }
1032         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1033                 border = path[depth].p_ext[1].ee_block;
1034                 ext_debug(inode, "leaf will be split."
1035                                 " next leaf starts at %d\n",
1036                                   le32_to_cpu(border));
1037         } else {
1038                 border = newext->ee_block;
1039                 ext_debug(inode, "leaf will be added."
1040                                 " next leaf starts at %d\n",
1041                                 le32_to_cpu(border));
1042         }
1043
1044         /*
1045          * If error occurs, then we break processing
1046          * and mark filesystem read-only. index won't
1047          * be inserted and tree will be in consistent
1048          * state. Next mount will repair buffers too.
1049          */
1050
1051         /*
1052          * Get array to track all allocated blocks.
1053          * We need this to handle errors and free blocks
1054          * upon them.
1055          */
1056         ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), gfp_flags);
1057         if (!ablocks)
1058                 return -ENOMEM;
1059
1060         /* allocate all needed blocks */
1061         ext_debug(inode, "allocate %d blocks for indexes/leaf\n", depth - at);
1062         for (a = 0; a < depth - at; a++) {
1063                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1064                                                    newext, &err, flags);
1065                 if (newblock == 0)
1066                         goto cleanup;
1067                 ablocks[a] = newblock;
1068         }
1069
1070         /* initialize new leaf */
1071         newblock = ablocks[--a];
1072         if (unlikely(newblock == 0)) {
1073                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1074                 err = -EFSCORRUPTED;
1075                 goto cleanup;
1076         }
1077         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1078         if (unlikely(!bh)) {
1079                 err = -ENOMEM;
1080                 goto cleanup;
1081         }
1082         lock_buffer(bh);
1083
1084         err = ext4_journal_get_create_access(handle, bh);
1085         if (err)
1086                 goto cleanup;
1087
1088         neh = ext_block_hdr(bh);
1089         neh->eh_entries = 0;
1090         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1091         neh->eh_magic = EXT4_EXT_MAGIC;
1092         neh->eh_depth = 0;
1093
1094         /* move remainder of path[depth] to the new leaf */
1095         if (unlikely(path[depth].p_hdr->eh_entries !=
1096                      path[depth].p_hdr->eh_max)) {
1097                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1098                                  path[depth].p_hdr->eh_entries,
1099                                  path[depth].p_hdr->eh_max);
1100                 err = -EFSCORRUPTED;
1101                 goto cleanup;
1102         }
1103         /* start copy from next extent */
1104         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1105         ext4_ext_show_move(inode, path, newblock, depth);
1106         if (m) {
1107                 struct ext4_extent *ex;
1108                 ex = EXT_FIRST_EXTENT(neh);
1109                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1110                 le16_add_cpu(&neh->eh_entries, m);
1111         }
1112
1113         /* zero out unused area in the extent block */
1114         ext_size = sizeof(struct ext4_extent_header) +
1115                 sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries);
1116         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1117         ext4_extent_block_csum_set(inode, neh);
1118         set_buffer_uptodate(bh);
1119         unlock_buffer(bh);
1120
1121         err = ext4_handle_dirty_metadata(handle, inode, bh);
1122         if (err)
1123                 goto cleanup;
1124         brelse(bh);
1125         bh = NULL;
1126
1127         /* correct old leaf */
1128         if (m) {
1129                 err = ext4_ext_get_access(handle, inode, path + depth);
1130                 if (err)
1131                         goto cleanup;
1132                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1133                 err = ext4_ext_dirty(handle, inode, path + depth);
1134                 if (err)
1135                         goto cleanup;
1136
1137         }
1138
1139         /* create intermediate indexes */
1140         k = depth - at - 1;
1141         if (unlikely(k < 0)) {
1142                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1143                 err = -EFSCORRUPTED;
1144                 goto cleanup;
1145         }
1146         if (k)
1147                 ext_debug(inode, "create %d intermediate indices\n", k);
1148         /* insert new index into current index block */
1149         /* current depth stored in i var */
1150         i = depth - 1;
1151         while (k--) {
1152                 oldblock = newblock;
1153                 newblock = ablocks[--a];
1154                 bh = sb_getblk(inode->i_sb, newblock);
1155                 if (unlikely(!bh)) {
1156                         err = -ENOMEM;
1157                         goto cleanup;
1158                 }
1159                 lock_buffer(bh);
1160
1161                 err = ext4_journal_get_create_access(handle, bh);
1162                 if (err)
1163                         goto cleanup;
1164
1165                 neh = ext_block_hdr(bh);
1166                 neh->eh_entries = cpu_to_le16(1);
1167                 neh->eh_magic = EXT4_EXT_MAGIC;
1168                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1169                 neh->eh_depth = cpu_to_le16(depth - i);
1170                 fidx = EXT_FIRST_INDEX(neh);
1171                 fidx->ei_block = border;
1172                 ext4_idx_store_pblock(fidx, oldblock);
1173
1174                 ext_debug(inode, "int.index at %d (block %llu): %u -> %llu\n",
1175                                 i, newblock, le32_to_cpu(border), oldblock);
1176
1177                 /* move remainder of path[i] to the new index block */
1178                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1179                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1180                         EXT4_ERROR_INODE(inode,
1181                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1182                                          le32_to_cpu(path[i].p_ext->ee_block));
1183                         err = -EFSCORRUPTED;
1184                         goto cleanup;
1185                 }
1186                 /* start copy indexes */
1187                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1188                 ext_debug(inode, "cur 0x%p, last 0x%p\n", path[i].p_idx,
1189                                 EXT_MAX_INDEX(path[i].p_hdr));
1190                 ext4_ext_show_move(inode, path, newblock, i);
1191                 if (m) {
1192                         memmove(++fidx, path[i].p_idx,
1193                                 sizeof(struct ext4_extent_idx) * m);
1194                         le16_add_cpu(&neh->eh_entries, m);
1195                 }
1196                 /* zero out unused area in the extent block */
1197                 ext_size = sizeof(struct ext4_extent_header) +
1198                    (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));
1199                 memset(bh->b_data + ext_size, 0,
1200                         inode->i_sb->s_blocksize - ext_size);
1201                 ext4_extent_block_csum_set(inode, neh);
1202                 set_buffer_uptodate(bh);
1203                 unlock_buffer(bh);
1204
1205                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1206                 if (err)
1207                         goto cleanup;
1208                 brelse(bh);
1209                 bh = NULL;
1210
1211                 /* correct old index */
1212                 if (m) {
1213                         err = ext4_ext_get_access(handle, inode, path + i);
1214                         if (err)
1215                                 goto cleanup;
1216                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1217                         err = ext4_ext_dirty(handle, inode, path + i);
1218                         if (err)
1219                                 goto cleanup;
1220                 }
1221
1222                 i--;
1223         }
1224
1225         /* insert new index */
1226         err = ext4_ext_insert_index(handle, inode, path + at,
1227                                     le32_to_cpu(border), newblock);
1228
1229 cleanup:
1230         if (bh) {
1231                 if (buffer_locked(bh))
1232                         unlock_buffer(bh);
1233                 brelse(bh);
1234         }
1235
1236         if (err) {
1237                 /* free all allocated blocks in error case */
1238                 for (i = 0; i < depth; i++) {
1239                         if (!ablocks[i])
1240                                 continue;
1241                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1242                                          EXT4_FREE_BLOCKS_METADATA);
1243                 }
1244         }
1245         kfree(ablocks);
1246
1247         return err;
1248 }
1249
1250 /*
1251  * ext4_ext_grow_indepth:
1252  * implements tree growing procedure:
1253  * - allocates new block
1254  * - moves top-level data (index block or leaf) into the new block
1255  * - initializes new top-level, creating index that points to the
1256  *   just created block
1257  */
1258 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1259                                  unsigned int flags)
1260 {
1261         struct ext4_extent_header *neh;
1262         struct buffer_head *bh;
1263         ext4_fsblk_t newblock, goal = 0;
1264         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1265         int err = 0;
1266         size_t ext_size = 0;
1267
1268         /* Try to prepend new index to old one */
1269         if (ext_depth(inode))
1270                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1271         if (goal > le32_to_cpu(es->s_first_data_block)) {
1272                 flags |= EXT4_MB_HINT_TRY_GOAL;
1273                 goal--;
1274         } else
1275                 goal = ext4_inode_to_goal_block(inode);
1276         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1277                                         NULL, &err);
1278         if (newblock == 0)
1279                 return err;
1280
1281         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1282         if (unlikely(!bh))
1283                 return -ENOMEM;
1284         lock_buffer(bh);
1285
1286         err = ext4_journal_get_create_access(handle, bh);
1287         if (err) {
1288                 unlock_buffer(bh);
1289                 goto out;
1290         }
1291
1292         ext_size = sizeof(EXT4_I(inode)->i_data);
1293         /* move top-level index/leaf into new block */
1294         memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);
1295         /* zero out unused area in the extent block */
1296         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1297
1298         /* set size of new block */
1299         neh = ext_block_hdr(bh);
1300         /* old root could have indexes or leaves
1301          * so calculate e_max right way */
1302         if (ext_depth(inode))
1303                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1304         else
1305                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1306         neh->eh_magic = EXT4_EXT_MAGIC;
1307         ext4_extent_block_csum_set(inode, neh);
1308         set_buffer_uptodate(bh);
1309         unlock_buffer(bh);
1310
1311         err = ext4_handle_dirty_metadata(handle, inode, bh);
1312         if (err)
1313                 goto out;
1314
1315         /* Update top-level index: num,max,pointer */
1316         neh = ext_inode_hdr(inode);
1317         neh->eh_entries = cpu_to_le16(1);
1318         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1319         if (neh->eh_depth == 0) {
1320                 /* Root extent block becomes index block */
1321                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1322                 EXT_FIRST_INDEX(neh)->ei_block =
1323                         EXT_FIRST_EXTENT(neh)->ee_block;
1324         }
1325         ext_debug(inode, "new root: num %d(%d), lblock %d, ptr %llu\n",
1326                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1327                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1328                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1329
1330         le16_add_cpu(&neh->eh_depth, 1);
1331         err = ext4_mark_inode_dirty(handle, inode);
1332 out:
1333         brelse(bh);
1334
1335         return err;
1336 }
1337
1338 /*
1339  * ext4_ext_create_new_leaf:
1340  * finds empty index and adds new leaf.
1341  * if no free index is found, then it requests in-depth growing.
1342  */
1343 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1344                                     unsigned int mb_flags,
1345                                     unsigned int gb_flags,
1346                                     struct ext4_ext_path **ppath,
1347                                     struct ext4_extent *newext)
1348 {
1349         struct ext4_ext_path *path = *ppath;
1350         struct ext4_ext_path *curp;
1351         int depth, i, err = 0;
1352
1353 repeat:
1354         i = depth = ext_depth(inode);
1355
1356         /* walk up to the tree and look for free index entry */
1357         curp = path + depth;
1358         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1359                 i--;
1360                 curp--;
1361         }
1362
1363         /* we use already allocated block for index block,
1364          * so subsequent data blocks should be contiguous */
1365         if (EXT_HAS_FREE_INDEX(curp)) {
1366                 /* if we found index with free entry, then use that
1367                  * entry: create all needed subtree and add new leaf */
1368                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1369                 if (err)
1370                         goto out;
1371
1372                 /* refill path */
1373                 path = ext4_find_extent(inode,
1374                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1375                                     ppath, gb_flags);
1376                 if (IS_ERR(path))
1377                         err = PTR_ERR(path);
1378         } else {
1379                 /* tree is full, time to grow in depth */
1380                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1381                 if (err)
1382                         goto out;
1383
1384                 /* refill path */
1385                 path = ext4_find_extent(inode,
1386                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1387                                     ppath, gb_flags);
1388                 if (IS_ERR(path)) {
1389                         err = PTR_ERR(path);
1390                         goto out;
1391                 }
1392
1393                 /*
1394                  * only first (depth 0 -> 1) produces free space;
1395                  * in all other cases we have to split the grown tree
1396                  */
1397                 depth = ext_depth(inode);
1398                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1399                         /* now we need to split */
1400                         goto repeat;
1401                 }
1402         }
1403
1404 out:
1405         return err;
1406 }
1407
1408 /*
1409  * search the closest allocated block to the left for *logical
1410  * and returns it at @logical + it's physical address at @phys
1411  * if *logical is the smallest allocated block, the function
1412  * returns 0 at @phys
1413  * return value contains 0 (success) or error code
1414  */
1415 static int ext4_ext_search_left(struct inode *inode,
1416                                 struct ext4_ext_path *path,
1417                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1418 {
1419         struct ext4_extent_idx *ix;
1420         struct ext4_extent *ex;
1421         int depth, ee_len;
1422
1423         if (unlikely(path == NULL)) {
1424                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1425                 return -EFSCORRUPTED;
1426         }
1427         depth = path->p_depth;
1428         *phys = 0;
1429
1430         if (depth == 0 && path->p_ext == NULL)
1431                 return 0;
1432
1433         /* usually extent in the path covers blocks smaller
1434          * then *logical, but it can be that extent is the
1435          * first one in the file */
1436
1437         ex = path[depth].p_ext;
1438         ee_len = ext4_ext_get_actual_len(ex);
1439         if (*logical < le32_to_cpu(ex->ee_block)) {
1440                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1441                         EXT4_ERROR_INODE(inode,
1442                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1443                                          *logical, le32_to_cpu(ex->ee_block));
1444                         return -EFSCORRUPTED;
1445                 }
1446                 while (--depth >= 0) {
1447                         ix = path[depth].p_idx;
1448                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1449                                 EXT4_ERROR_INODE(inode,
1450                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1451                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1452                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1453                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1454                                   depth);
1455                                 return -EFSCORRUPTED;
1456                         }
1457                 }
1458                 return 0;
1459         }
1460
1461         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1462                 EXT4_ERROR_INODE(inode,
1463                                  "logical %d < ee_block %d + ee_len %d!",
1464                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1465                 return -EFSCORRUPTED;
1466         }
1467
1468         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1469         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1470         return 0;
1471 }
1472
1473 /*
1474  * search the closest allocated block to the right for *logical
1475  * and returns it at @logical + it's physical address at @phys
1476  * if *logical is the largest allocated block, the function
1477  * returns 0 at @phys
1478  * return value contains 0 (success) or error code
1479  */
1480 static int ext4_ext_search_right(struct inode *inode,
1481                                  struct ext4_ext_path *path,
1482                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1483                                  struct ext4_extent **ret_ex)
1484 {
1485         struct buffer_head *bh = NULL;
1486         struct ext4_extent_header *eh;
1487         struct ext4_extent_idx *ix;
1488         struct ext4_extent *ex;
1489         ext4_fsblk_t block;
1490         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1491         int ee_len;
1492
1493         if (unlikely(path == NULL)) {
1494                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1495                 return -EFSCORRUPTED;
1496         }
1497         depth = path->p_depth;
1498         *phys = 0;
1499
1500         if (depth == 0 && path->p_ext == NULL)
1501                 return 0;
1502
1503         /* usually extent in the path covers blocks smaller
1504          * then *logical, but it can be that extent is the
1505          * first one in the file */
1506
1507         ex = path[depth].p_ext;
1508         ee_len = ext4_ext_get_actual_len(ex);
1509         if (*logical < le32_to_cpu(ex->ee_block)) {
1510                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1511                         EXT4_ERROR_INODE(inode,
1512                                          "first_extent(path[%d].p_hdr) != ex",
1513                                          depth);
1514                         return -EFSCORRUPTED;
1515                 }
1516                 while (--depth >= 0) {
1517                         ix = path[depth].p_idx;
1518                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1519                                 EXT4_ERROR_INODE(inode,
1520                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1521                                                  *logical);
1522                                 return -EFSCORRUPTED;
1523                         }
1524                 }
1525                 goto found_extent;
1526         }
1527
1528         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1529                 EXT4_ERROR_INODE(inode,
1530                                  "logical %d < ee_block %d + ee_len %d!",
1531                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1532                 return -EFSCORRUPTED;
1533         }
1534
1535         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1536                 /* next allocated block in this leaf */
1537                 ex++;
1538                 goto found_extent;
1539         }
1540
1541         /* go up and search for index to the right */
1542         while (--depth >= 0) {
1543                 ix = path[depth].p_idx;
1544                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1545                         goto got_index;
1546         }
1547
1548         /* we've gone up to the root and found no index to the right */
1549         return 0;
1550
1551 got_index:
1552         /* we've found index to the right, let's
1553          * follow it and find the closest allocated
1554          * block to the right */
1555         ix++;
1556         block = ext4_idx_pblock(ix);
1557         while (++depth < path->p_depth) {
1558                 /* subtract from p_depth to get proper eh_depth */
1559                 bh = read_extent_tree_block(inode, block,
1560                                             path->p_depth - depth, 0);
1561                 if (IS_ERR(bh))
1562                         return PTR_ERR(bh);
1563                 eh = ext_block_hdr(bh);
1564                 ix = EXT_FIRST_INDEX(eh);
1565                 block = ext4_idx_pblock(ix);
1566                 put_bh(bh);
1567         }
1568
1569         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1570         if (IS_ERR(bh))
1571                 return PTR_ERR(bh);
1572         eh = ext_block_hdr(bh);
1573         ex = EXT_FIRST_EXTENT(eh);
1574 found_extent:
1575         *logical = le32_to_cpu(ex->ee_block);
1576         *phys = ext4_ext_pblock(ex);
1577         *ret_ex = ex;
1578         if (bh)
1579                 put_bh(bh);
1580         return 0;
1581 }
1582
1583 /*
1584  * ext4_ext_next_allocated_block:
1585  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1586  * NOTE: it considers block number from index entry as
1587  * allocated block. Thus, index entries have to be consistent
1588  * with leaves.
1589  */
1590 ext4_lblk_t
1591 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1592 {
1593         int depth;
1594
1595         BUG_ON(path == NULL);
1596         depth = path->p_depth;
1597
1598         if (depth == 0 && path->p_ext == NULL)
1599                 return EXT_MAX_BLOCKS;
1600
1601         while (depth >= 0) {
1602                 struct ext4_ext_path *p = &path[depth];
1603
1604                 if (depth == path->p_depth) {
1605                         /* leaf */
1606                         if (p->p_ext && p->p_ext != EXT_LAST_EXTENT(p->p_hdr))
1607                                 return le32_to_cpu(p->p_ext[1].ee_block);
1608                 } else {
1609                         /* index */
1610                         if (p->p_idx != EXT_LAST_INDEX(p->p_hdr))
1611                                 return le32_to_cpu(p->p_idx[1].ei_block);
1612                 }
1613                 depth--;
1614         }
1615
1616         return EXT_MAX_BLOCKS;
1617 }
1618
1619 /*
1620  * ext4_ext_next_leaf_block:
1621  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1622  */
1623 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1624 {
1625         int depth;
1626
1627         BUG_ON(path == NULL);
1628         depth = path->p_depth;
1629
1630         /* zero-tree has no leaf blocks at all */
1631         if (depth == 0)
1632                 return EXT_MAX_BLOCKS;
1633
1634         /* go to index block */
1635         depth--;
1636
1637         while (depth >= 0) {
1638                 if (path[depth].p_idx !=
1639                                 EXT_LAST_INDEX(path[depth].p_hdr))
1640                         return (ext4_lblk_t)
1641                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1642                 depth--;
1643         }
1644
1645         return EXT_MAX_BLOCKS;
1646 }
1647
1648 /*
1649  * ext4_ext_correct_indexes:
1650  * if leaf gets modified and modified extent is first in the leaf,
1651  * then we have to correct all indexes above.
1652  * TODO: do we need to correct tree in all cases?
1653  */
1654 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1655                                 struct ext4_ext_path *path)
1656 {
1657         struct ext4_extent_header *eh;
1658         int depth = ext_depth(inode);
1659         struct ext4_extent *ex;
1660         __le32 border;
1661         int k, err = 0;
1662
1663         eh = path[depth].p_hdr;
1664         ex = path[depth].p_ext;
1665
1666         if (unlikely(ex == NULL || eh == NULL)) {
1667                 EXT4_ERROR_INODE(inode,
1668                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1669                 return -EFSCORRUPTED;
1670         }
1671
1672         if (depth == 0) {
1673                 /* there is no tree at all */
1674                 return 0;
1675         }
1676
1677         if (ex != EXT_FIRST_EXTENT(eh)) {
1678                 /* we correct tree if first leaf got modified only */
1679                 return 0;
1680         }
1681
1682         /*
1683          * TODO: we need correction if border is smaller than current one
1684          */
1685         k = depth - 1;
1686         border = path[depth].p_ext->ee_block;
1687         err = ext4_ext_get_access(handle, inode, path + k);
1688         if (err)
1689                 return err;
1690         path[k].p_idx->ei_block = border;
1691         err = ext4_ext_dirty(handle, inode, path + k);
1692         if (err)
1693                 return err;
1694
1695         while (k--) {
1696                 /* change all left-side indexes */
1697                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1698                         break;
1699                 err = ext4_ext_get_access(handle, inode, path + k);
1700                 if (err)
1701                         break;
1702                 path[k].p_idx->ei_block = border;
1703                 err = ext4_ext_dirty(handle, inode, path + k);
1704                 if (err)
1705                         break;
1706         }
1707
1708         return err;
1709 }
1710
1711 static int ext4_can_extents_be_merged(struct inode *inode,
1712                                       struct ext4_extent *ex1,
1713                                       struct ext4_extent *ex2)
1714 {
1715         unsigned short ext1_ee_len, ext2_ee_len;
1716
1717         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1718                 return 0;
1719
1720         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1721         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1722
1723         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1724                         le32_to_cpu(ex2->ee_block))
1725                 return 0;
1726
1727         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1728                 return 0;
1729
1730         if (ext4_ext_is_unwritten(ex1) &&
1731             ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)
1732                 return 0;
1733 #ifdef AGGRESSIVE_TEST
1734         if (ext1_ee_len >= 4)
1735                 return 0;
1736 #endif
1737
1738         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1739                 return 1;
1740         return 0;
1741 }
1742
1743 /*
1744  * This function tries to merge the "ex" extent to the next extent in the tree.
1745  * It always tries to merge towards right. If you want to merge towards
1746  * left, pass "ex - 1" as argument instead of "ex".
1747  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1748  * 1 if they got merged.
1749  */
1750 static int ext4_ext_try_to_merge_right(struct inode *inode,
1751                                  struct ext4_ext_path *path,
1752                                  struct ext4_extent *ex)
1753 {
1754         struct ext4_extent_header *eh;
1755         unsigned int depth, len;
1756         int merge_done = 0, unwritten;
1757
1758         depth = ext_depth(inode);
1759         BUG_ON(path[depth].p_hdr == NULL);
1760         eh = path[depth].p_hdr;
1761
1762         while (ex < EXT_LAST_EXTENT(eh)) {
1763                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1764                         break;
1765                 /* merge with next extent! */
1766                 unwritten = ext4_ext_is_unwritten(ex);
1767                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1768                                 + ext4_ext_get_actual_len(ex + 1));
1769                 if (unwritten)
1770                         ext4_ext_mark_unwritten(ex);
1771
1772                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1773                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1774                                 * sizeof(struct ext4_extent);
1775                         memmove(ex + 1, ex + 2, len);
1776                 }
1777                 le16_add_cpu(&eh->eh_entries, -1);
1778                 merge_done = 1;
1779                 WARN_ON(eh->eh_entries == 0);
1780                 if (!eh->eh_entries)
1781                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1782         }
1783
1784         return merge_done;
1785 }
1786
1787 /*
1788  * This function does a very simple check to see if we can collapse
1789  * an extent tree with a single extent tree leaf block into the inode.
1790  */
1791 static void ext4_ext_try_to_merge_up(handle_t *handle,
1792                                      struct inode *inode,
1793                                      struct ext4_ext_path *path)
1794 {
1795         size_t s;
1796         unsigned max_root = ext4_ext_space_root(inode, 0);
1797         ext4_fsblk_t blk;
1798
1799         if ((path[0].p_depth != 1) ||
1800             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1801             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1802                 return;
1803
1804         /*
1805          * We need to modify the block allocation bitmap and the block
1806          * group descriptor to release the extent tree block.  If we
1807          * can't get the journal credits, give up.
1808          */
1809         if (ext4_journal_extend(handle, 2,
1810                         ext4_free_metadata_revoke_credits(inode->i_sb, 1)))
1811                 return;
1812
1813         /*
1814          * Copy the extent data up to the inode
1815          */
1816         blk = ext4_idx_pblock(path[0].p_idx);
1817         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1818                 sizeof(struct ext4_extent_idx);
1819         s += sizeof(struct ext4_extent_header);
1820
1821         path[1].p_maxdepth = path[0].p_maxdepth;
1822         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1823         path[0].p_depth = 0;
1824         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1825                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1826         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1827
1828         brelse(path[1].p_bh);
1829         ext4_free_blocks(handle, inode, NULL, blk, 1,
1830                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1831 }
1832
1833 /*
1834  * This function tries to merge the @ex extent to neighbours in the tree, then
1835  * tries to collapse the extent tree into the inode.
1836  */
1837 static void ext4_ext_try_to_merge(handle_t *handle,
1838                                   struct inode *inode,
1839                                   struct ext4_ext_path *path,
1840                                   struct ext4_extent *ex)
1841 {
1842         struct ext4_extent_header *eh;
1843         unsigned int depth;
1844         int merge_done = 0;
1845
1846         depth = ext_depth(inode);
1847         BUG_ON(path[depth].p_hdr == NULL);
1848         eh = path[depth].p_hdr;
1849
1850         if (ex > EXT_FIRST_EXTENT(eh))
1851                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1852
1853         if (!merge_done)
1854                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1855
1856         ext4_ext_try_to_merge_up(handle, inode, path);
1857 }
1858
1859 /*
1860  * check if a portion of the "newext" extent overlaps with an
1861  * existing extent.
1862  *
1863  * If there is an overlap discovered, it updates the length of the newext
1864  * such that there will be no overlap, and then returns 1.
1865  * If there is no overlap found, it returns 0.
1866  */
1867 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1868                                            struct inode *inode,
1869                                            struct ext4_extent *newext,
1870                                            struct ext4_ext_path *path)
1871 {
1872         ext4_lblk_t b1, b2;
1873         unsigned int depth, len1;
1874         unsigned int ret = 0;
1875
1876         b1 = le32_to_cpu(newext->ee_block);
1877         len1 = ext4_ext_get_actual_len(newext);
1878         depth = ext_depth(inode);
1879         if (!path[depth].p_ext)
1880                 goto out;
1881         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1882
1883         /*
1884          * get the next allocated block if the extent in the path
1885          * is before the requested block(s)
1886          */
1887         if (b2 < b1) {
1888                 b2 = ext4_ext_next_allocated_block(path);
1889                 if (b2 == EXT_MAX_BLOCKS)
1890                         goto out;
1891                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1892         }
1893
1894         /* check for wrap through zero on extent logical start block*/
1895         if (b1 + len1 < b1) {
1896                 len1 = EXT_MAX_BLOCKS - b1;
1897                 newext->ee_len = cpu_to_le16(len1);
1898                 ret = 1;
1899         }
1900
1901         /* check for overlap */
1902         if (b1 + len1 > b2) {
1903                 newext->ee_len = cpu_to_le16(b2 - b1);
1904                 ret = 1;
1905         }
1906 out:
1907         return ret;
1908 }
1909
1910 /*
1911  * ext4_ext_insert_extent:
1912  * tries to merge requested extent into the existing extent or
1913  * inserts requested extent as new one into the tree,
1914  * creating new leaf in the no-space case.
1915  */
1916 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1917                                 struct ext4_ext_path **ppath,
1918                                 struct ext4_extent *newext, int gb_flags)
1919 {
1920         struct ext4_ext_path *path = *ppath;
1921         struct ext4_extent_header *eh;
1922         struct ext4_extent *ex, *fex;
1923         struct ext4_extent *nearex; /* nearest extent */
1924         struct ext4_ext_path *npath = NULL;
1925         int depth, len, err;
1926         ext4_lblk_t next;
1927         int mb_flags = 0, unwritten;
1928
1929         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1930                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1931         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1932                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1933                 return -EFSCORRUPTED;
1934         }
1935         depth = ext_depth(inode);
1936         ex = path[depth].p_ext;
1937         eh = path[depth].p_hdr;
1938         if (unlikely(path[depth].p_hdr == NULL)) {
1939                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1940                 return -EFSCORRUPTED;
1941         }
1942
1943         /* try to insert block into found extent and return */
1944         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1945
1946                 /*
1947                  * Try to see whether we should rather test the extent on
1948                  * right from ex, or from the left of ex. This is because
1949                  * ext4_find_extent() can return either extent on the
1950                  * left, or on the right from the searched position. This
1951                  * will make merging more effective.
1952                  */
1953                 if (ex < EXT_LAST_EXTENT(eh) &&
1954                     (le32_to_cpu(ex->ee_block) +
1955                     ext4_ext_get_actual_len(ex) <
1956                     le32_to_cpu(newext->ee_block))) {
1957                         ex += 1;
1958                         goto prepend;
1959                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1960                            (le32_to_cpu(newext->ee_block) +
1961                            ext4_ext_get_actual_len(newext) <
1962                            le32_to_cpu(ex->ee_block)))
1963                         ex -= 1;
1964
1965                 /* Try to append newex to the ex */
1966                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1967                         ext_debug(inode, "append [%d]%d block to %u:[%d]%d"
1968                                   "(from %llu)\n",
1969                                   ext4_ext_is_unwritten(newext),
1970                                   ext4_ext_get_actual_len(newext),
1971                                   le32_to_cpu(ex->ee_block),
1972                                   ext4_ext_is_unwritten(ex),
1973                                   ext4_ext_get_actual_len(ex),
1974                                   ext4_ext_pblock(ex));
1975                         err = ext4_ext_get_access(handle, inode,
1976                                                   path + depth);
1977                         if (err)
1978                                 return err;
1979                         unwritten = ext4_ext_is_unwritten(ex);
1980                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1981                                         + ext4_ext_get_actual_len(newext));
1982                         if (unwritten)
1983                                 ext4_ext_mark_unwritten(ex);
1984                         eh = path[depth].p_hdr;
1985                         nearex = ex;
1986                         goto merge;
1987                 }
1988
1989 prepend:
1990                 /* Try to prepend newex to the ex */
1991                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
1992                         ext_debug(inode, "prepend %u[%d]%d block to %u:[%d]%d"
1993                                   "(from %llu)\n",
1994                                   le32_to_cpu(newext->ee_block),
1995                                   ext4_ext_is_unwritten(newext),
1996                                   ext4_ext_get_actual_len(newext),
1997                                   le32_to_cpu(ex->ee_block),
1998                                   ext4_ext_is_unwritten(ex),
1999                                   ext4_ext_get_actual_len(ex),
2000                                   ext4_ext_pblock(ex));
2001                         err = ext4_ext_get_access(handle, inode,
2002                                                   path + depth);
2003                         if (err)
2004                                 return err;
2005
2006                         unwritten = ext4_ext_is_unwritten(ex);
2007                         ex->ee_block = newext->ee_block;
2008                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2009                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2010                                         + ext4_ext_get_actual_len(newext));
2011                         if (unwritten)
2012                                 ext4_ext_mark_unwritten(ex);
2013                         eh = path[depth].p_hdr;
2014                         nearex = ex;
2015                         goto merge;
2016                 }
2017         }
2018
2019         depth = ext_depth(inode);
2020         eh = path[depth].p_hdr;
2021         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2022                 goto has_space;
2023
2024         /* probably next leaf has space for us? */
2025         fex = EXT_LAST_EXTENT(eh);
2026         next = EXT_MAX_BLOCKS;
2027         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2028                 next = ext4_ext_next_leaf_block(path);
2029         if (next != EXT_MAX_BLOCKS) {
2030                 ext_debug(inode, "next leaf block - %u\n", next);
2031                 BUG_ON(npath != NULL);
2032                 npath = ext4_find_extent(inode, next, NULL, gb_flags);
2033                 if (IS_ERR(npath))
2034                         return PTR_ERR(npath);
2035                 BUG_ON(npath->p_depth != path->p_depth);
2036                 eh = npath[depth].p_hdr;
2037                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2038                         ext_debug(inode, "next leaf isn't full(%d)\n",
2039                                   le16_to_cpu(eh->eh_entries));
2040                         path = npath;
2041                         goto has_space;
2042                 }
2043                 ext_debug(inode, "next leaf has no free space(%d,%d)\n",
2044                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2045         }
2046
2047         /*
2048          * There is no free space in the found leaf.
2049          * We're gonna add a new leaf in the tree.
2050          */
2051         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2052                 mb_flags |= EXT4_MB_USE_RESERVED;
2053         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2054                                        ppath, newext);
2055         if (err)
2056                 goto cleanup;
2057         depth = ext_depth(inode);
2058         eh = path[depth].p_hdr;
2059
2060 has_space:
2061         nearex = path[depth].p_ext;
2062
2063         err = ext4_ext_get_access(handle, inode, path + depth);
2064         if (err)
2065                 goto cleanup;
2066
2067         if (!nearex) {
2068                 /* there is no extent in this leaf, create first one */
2069                 ext_debug(inode, "first extent in the leaf: %u:%llu:[%d]%d\n",
2070                                 le32_to_cpu(newext->ee_block),
2071                                 ext4_ext_pblock(newext),
2072                                 ext4_ext_is_unwritten(newext),
2073                                 ext4_ext_get_actual_len(newext));
2074                 nearex = EXT_FIRST_EXTENT(eh);
2075         } else {
2076                 if (le32_to_cpu(newext->ee_block)
2077                            > le32_to_cpu(nearex->ee_block)) {
2078                         /* Insert after */
2079                         ext_debug(inode, "insert %u:%llu:[%d]%d before: "
2080                                         "nearest %p\n",
2081                                         le32_to_cpu(newext->ee_block),
2082                                         ext4_ext_pblock(newext),
2083                                         ext4_ext_is_unwritten(newext),
2084                                         ext4_ext_get_actual_len(newext),
2085                                         nearex);
2086                         nearex++;
2087                 } else {
2088                         /* Insert before */
2089                         BUG_ON(newext->ee_block == nearex->ee_block);
2090                         ext_debug(inode, "insert %u:%llu:[%d]%d after: "
2091                                         "nearest %p\n",
2092                                         le32_to_cpu(newext->ee_block),
2093                                         ext4_ext_pblock(newext),
2094                                         ext4_ext_is_unwritten(newext),
2095                                         ext4_ext_get_actual_len(newext),
2096                                         nearex);
2097                 }
2098                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2099                 if (len > 0) {
2100                         ext_debug(inode, "insert %u:%llu:[%d]%d: "
2101                                         "move %d extents from 0x%p to 0x%p\n",
2102                                         le32_to_cpu(newext->ee_block),
2103                                         ext4_ext_pblock(newext),
2104                                         ext4_ext_is_unwritten(newext),
2105                                         ext4_ext_get_actual_len(newext),
2106                                         len, nearex, nearex + 1);
2107                         memmove(nearex + 1, nearex,
2108                                 len * sizeof(struct ext4_extent));
2109                 }
2110         }
2111
2112         le16_add_cpu(&eh->eh_entries, 1);
2113         path[depth].p_ext = nearex;
2114         nearex->ee_block = newext->ee_block;
2115         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2116         nearex->ee_len = newext->ee_len;
2117
2118 merge:
2119         /* try to merge extents */
2120         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2121                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2122
2123
2124         /* time to correct all indexes above */
2125         err = ext4_ext_correct_indexes(handle, inode, path);
2126         if (err)
2127                 goto cleanup;
2128
2129         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2130
2131 cleanup:
2132         ext4_ext_drop_refs(npath);
2133         kfree(npath);
2134         return err;
2135 }
2136
2137 static int ext4_fill_es_cache_info(struct inode *inode,
2138                                    ext4_lblk_t block, ext4_lblk_t num,
2139                                    struct fiemap_extent_info *fieinfo)
2140 {
2141         ext4_lblk_t next, end = block + num - 1;
2142         struct extent_status es;
2143         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2144         unsigned int flags;
2145         int err;
2146
2147         while (block <= end) {
2148                 next = 0;
2149                 flags = 0;
2150                 if (!ext4_es_lookup_extent(inode, block, &next, &es))
2151                         break;
2152                 if (ext4_es_is_unwritten(&es))
2153                         flags |= FIEMAP_EXTENT_UNWRITTEN;
2154                 if (ext4_es_is_delayed(&es))
2155                         flags |= (FIEMAP_EXTENT_DELALLOC |
2156                                   FIEMAP_EXTENT_UNKNOWN);
2157                 if (ext4_es_is_hole(&es))
2158                         flags |= EXT4_FIEMAP_EXTENT_HOLE;
2159                 if (next == 0)
2160                         flags |= FIEMAP_EXTENT_LAST;
2161                 if (flags & (FIEMAP_EXTENT_DELALLOC|
2162                              EXT4_FIEMAP_EXTENT_HOLE))
2163                         es.es_pblk = 0;
2164                 else
2165                         es.es_pblk = ext4_es_pblock(&es);
2166                 err = fiemap_fill_next_extent(fieinfo,
2167                                 (__u64)es.es_lblk << blksize_bits,
2168                                 (__u64)es.es_pblk << blksize_bits,
2169                                 (__u64)es.es_len << blksize_bits,
2170                                 flags);
2171                 if (next == 0)
2172                         break;
2173                 block = next;
2174                 if (err < 0)
2175                         return err;
2176                 if (err == 1)
2177                         return 0;
2178         }
2179         return 0;
2180 }
2181
2182
2183 /*
2184  * ext4_ext_determine_hole - determine hole around given block
2185  * @inode:      inode we lookup in
2186  * @path:       path in extent tree to @lblk
2187  * @lblk:       pointer to logical block around which we want to determine hole
2188  *
2189  * Determine hole length (and start if easily possible) around given logical
2190  * block. We don't try too hard to find the beginning of the hole but @path
2191  * actually points to extent before @lblk, we provide it.
2192  *
2193  * The function returns the length of a hole starting at @lblk. We update @lblk
2194  * to the beginning of the hole if we managed to find it.
2195  */
2196 static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2197                                            struct ext4_ext_path *path,
2198                                            ext4_lblk_t *lblk)
2199 {
2200         int depth = ext_depth(inode);
2201         struct ext4_extent *ex;
2202         ext4_lblk_t len;
2203
2204         ex = path[depth].p_ext;
2205         if (ex == NULL) {
2206                 /* there is no extent yet, so gap is [0;-] */
2207                 *lblk = 0;
2208                 len = EXT_MAX_BLOCKS;
2209         } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2210                 len = le32_to_cpu(ex->ee_block) - *lblk;
2211         } else if (*lblk >= le32_to_cpu(ex->ee_block)
2212                         + ext4_ext_get_actual_len(ex)) {
2213                 ext4_lblk_t next;
2214
2215                 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2216                 next = ext4_ext_next_allocated_block(path);
2217                 BUG_ON(next == *lblk);
2218                 len = next - *lblk;
2219         } else {
2220                 BUG();
2221         }
2222         return len;
2223 }
2224
2225 /*
2226  * ext4_ext_put_gap_in_cache:
2227  * calculate boundaries of the gap that the requested block fits into
2228  * and cache this gap
2229  */
2230 static void
2231 ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2232                           ext4_lblk_t hole_len)
2233 {
2234         struct extent_status es;
2235
2236         ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
2237                                   hole_start + hole_len - 1, &es);
2238         if (es.es_len) {
2239                 /* There's delayed extent containing lblock? */
2240                 if (es.es_lblk <= hole_start)
2241                         return;
2242                 hole_len = min(es.es_lblk - hole_start, hole_len);
2243         }
2244         ext_debug(inode, " -> %u:%u\n", hole_start, hole_len);
2245         ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2246                               EXTENT_STATUS_HOLE);
2247 }
2248
2249 /*
2250  * ext4_ext_rm_idx:
2251  * removes index from the index block.
2252  */
2253 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2254                         struct ext4_ext_path *path, int depth)
2255 {
2256         int err;
2257         ext4_fsblk_t leaf;
2258
2259         /* free index block */
2260         depth--;
2261         path = path + depth;
2262         leaf = ext4_idx_pblock(path->p_idx);
2263         if (unlikely(path->p_hdr->eh_entries == 0)) {
2264                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2265                 return -EFSCORRUPTED;
2266         }
2267         err = ext4_ext_get_access(handle, inode, path);
2268         if (err)
2269                 return err;
2270
2271         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2272                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2273                 len *= sizeof(struct ext4_extent_idx);
2274                 memmove(path->p_idx, path->p_idx + 1, len);
2275         }
2276
2277         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2278         err = ext4_ext_dirty(handle, inode, path);
2279         if (err)
2280                 return err;
2281         ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
2282         trace_ext4_ext_rm_idx(inode, leaf);
2283
2284         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2285                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2286
2287         while (--depth >= 0) {
2288                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2289                         break;
2290                 path--;
2291                 err = ext4_ext_get_access(handle, inode, path);
2292                 if (err)
2293                         break;
2294                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2295                 err = ext4_ext_dirty(handle, inode, path);
2296                 if (err)
2297                         break;
2298         }
2299         return err;
2300 }
2301
2302 /*
2303  * ext4_ext_calc_credits_for_single_extent:
2304  * This routine returns max. credits that needed to insert an extent
2305  * to the extent tree.
2306  * When pass the actual path, the caller should calculate credits
2307  * under i_data_sem.
2308  */
2309 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2310                                                 struct ext4_ext_path *path)
2311 {
2312         if (path) {
2313                 int depth = ext_depth(inode);
2314                 int ret = 0;
2315
2316                 /* probably there is space in leaf? */
2317                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2318                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2319
2320                         /*
2321                          *  There are some space in the leaf tree, no
2322                          *  need to account for leaf block credit
2323                          *
2324                          *  bitmaps and block group descriptor blocks
2325                          *  and other metadata blocks still need to be
2326                          *  accounted.
2327                          */
2328                         /* 1 bitmap, 1 block group descriptor */
2329                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2330                         return ret;
2331                 }
2332         }
2333
2334         return ext4_chunk_trans_blocks(inode, nrblocks);
2335 }
2336
2337 /*
2338  * How many index/leaf blocks need to change/allocate to add @extents extents?
2339  *
2340  * If we add a single extent, then in the worse case, each tree level
2341  * index/leaf need to be changed in case of the tree split.
2342  *
2343  * If more extents are inserted, they could cause the whole tree split more
2344  * than once, but this is really rare.
2345  */
2346 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2347 {
2348         int index;
2349         int depth;
2350
2351         /* If we are converting the inline data, only one is needed here. */
2352         if (ext4_has_inline_data(inode))
2353                 return 1;
2354
2355         depth = ext_depth(inode);
2356
2357         if (extents <= 1)
2358                 index = depth * 2;
2359         else
2360                 index = depth * 3;
2361
2362         return index;
2363 }
2364
2365 static inline int get_default_free_blocks_flags(struct inode *inode)
2366 {
2367         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2368             ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2369                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2370         else if (ext4_should_journal_data(inode))
2371                 return EXT4_FREE_BLOCKS_FORGET;
2372         return 0;
2373 }
2374
2375 /*
2376  * ext4_rereserve_cluster - increment the reserved cluster count when
2377  *                          freeing a cluster with a pending reservation
2378  *
2379  * @inode - file containing the cluster
2380  * @lblk - logical block in cluster to be reserved
2381  *
2382  * Increments the reserved cluster count and adjusts quota in a bigalloc
2383  * file system when freeing a partial cluster containing at least one
2384  * delayed and unwritten block.  A partial cluster meeting that
2385  * requirement will have a pending reservation.  If so, the
2386  * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2387  * defer reserved and allocated space accounting to a subsequent call
2388  * to this function.
2389  */
2390 static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2391 {
2392         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2393         struct ext4_inode_info *ei = EXT4_I(inode);
2394
2395         dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2396
2397         spin_lock(&ei->i_block_reservation_lock);
2398         ei->i_reserved_data_blocks++;
2399         percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2400         spin_unlock(&ei->i_block_reservation_lock);
2401
2402         percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2403         ext4_remove_pending(inode, lblk);
2404 }
2405
2406 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2407                               struct ext4_extent *ex,
2408                               struct partial_cluster *partial,
2409                               ext4_lblk_t from, ext4_lblk_t to)
2410 {
2411         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2412         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2413         ext4_fsblk_t last_pblk, pblk;
2414         ext4_lblk_t num;
2415         int flags;
2416
2417         /* only extent tail removal is allowed */
2418         if (from < le32_to_cpu(ex->ee_block) ||
2419             to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2420                 ext4_error(sbi->s_sb,
2421                            "strange request: removal(2) %u-%u from %u:%u",
2422                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2423                 return 0;
2424         }
2425
2426 #ifdef EXTENTS_STATS
2427         spin_lock(&sbi->s_ext_stats_lock);
2428         sbi->s_ext_blocks += ee_len;
2429         sbi->s_ext_extents++;
2430         if (ee_len < sbi->s_ext_min)
2431                 sbi->s_ext_min = ee_len;
2432         if (ee_len > sbi->s_ext_max)
2433                 sbi->s_ext_max = ee_len;
2434         if (ext_depth(inode) > sbi->s_depth_max)
2435                 sbi->s_depth_max = ext_depth(inode);
2436         spin_unlock(&sbi->s_ext_stats_lock);
2437 #endif
2438
2439         trace_ext4_remove_blocks(inode, ex, from, to, partial);
2440
2441         /*
2442          * if we have a partial cluster, and it's different from the
2443          * cluster of the last block in the extent, we free it
2444          */
2445         last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2446
2447         if (partial->state != initial &&
2448             partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2449                 if (partial->state == tofree) {
2450                         flags = get_default_free_blocks_flags(inode);
2451                         if (ext4_is_pending(inode, partial->lblk))
2452                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2453                         ext4_free_blocks(handle, inode, NULL,
2454                                          EXT4_C2B(sbi, partial->pclu),
2455                                          sbi->s_cluster_ratio, flags);
2456                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2457                                 ext4_rereserve_cluster(inode, partial->lblk);
2458                 }
2459                 partial->state = initial;
2460         }
2461
2462         num = le32_to_cpu(ex->ee_block) + ee_len - from;
2463         pblk = ext4_ext_pblock(ex) + ee_len - num;
2464
2465         /*
2466          * We free the partial cluster at the end of the extent (if any),
2467          * unless the cluster is used by another extent (partial_cluster
2468          * state is nofree).  If a partial cluster exists here, it must be
2469          * shared with the last block in the extent.
2470          */
2471         flags = get_default_free_blocks_flags(inode);
2472
2473         /* partial, left end cluster aligned, right end unaligned */
2474         if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2475             (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2476             (partial->state != nofree)) {
2477                 if (ext4_is_pending(inode, to))
2478                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2479                 ext4_free_blocks(handle, inode, NULL,
2480                                  EXT4_PBLK_CMASK(sbi, last_pblk),
2481                                  sbi->s_cluster_ratio, flags);
2482                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2483                         ext4_rereserve_cluster(inode, to);
2484                 partial->state = initial;
2485                 flags = get_default_free_blocks_flags(inode);
2486         }
2487
2488         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2489
2490         /*
2491          * For bigalloc file systems, we never free a partial cluster
2492          * at the beginning of the extent.  Instead, we check to see if we
2493          * need to free it on a subsequent call to ext4_remove_blocks,
2494          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2495          */
2496         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2497         ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2498
2499         /* reset the partial cluster if we've freed past it */
2500         if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2501                 partial->state = initial;
2502
2503         /*
2504          * If we've freed the entire extent but the beginning is not left
2505          * cluster aligned and is not marked as ineligible for freeing we
2506          * record the partial cluster at the beginning of the extent.  It
2507          * wasn't freed by the preceding ext4_free_blocks() call, and we
2508          * need to look farther to the left to determine if it's to be freed
2509          * (not shared with another extent). Else, reset the partial
2510          * cluster - we're either  done freeing or the beginning of the
2511          * extent is left cluster aligned.
2512          */
2513         if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2514                 if (partial->state == initial) {
2515                         partial->pclu = EXT4_B2C(sbi, pblk);
2516                         partial->lblk = from;
2517                         partial->state = tofree;
2518                 }
2519         } else {
2520                 partial->state = initial;
2521         }
2522
2523         return 0;
2524 }
2525
2526 /*
2527  * ext4_ext_rm_leaf() Removes the extents associated with the
2528  * blocks appearing between "start" and "end".  Both "start"
2529  * and "end" must appear in the same extent or EIO is returned.
2530  *
2531  * @handle: The journal handle
2532  * @inode:  The files inode
2533  * @path:   The path to the leaf
2534  * @partial_cluster: The cluster which we'll have to free if all extents
2535  *                   has been released from it.  However, if this value is
2536  *                   negative, it's a cluster just to the right of the
2537  *                   punched region and it must not be freed.
2538  * @start:  The first block to remove
2539  * @end:   The last block to remove
2540  */
2541 static int
2542 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2543                  struct ext4_ext_path *path,
2544                  struct partial_cluster *partial,
2545                  ext4_lblk_t start, ext4_lblk_t end)
2546 {
2547         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2548         int err = 0, correct_index = 0;
2549         int depth = ext_depth(inode), credits, revoke_credits;
2550         struct ext4_extent_header *eh;
2551         ext4_lblk_t a, b;
2552         unsigned num;
2553         ext4_lblk_t ex_ee_block;
2554         unsigned short ex_ee_len;
2555         unsigned unwritten = 0;
2556         struct ext4_extent *ex;
2557         ext4_fsblk_t pblk;
2558
2559         /* the header must be checked already in ext4_ext_remove_space() */
2560         ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
2561         if (!path[depth].p_hdr)
2562                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2563         eh = path[depth].p_hdr;
2564         if (unlikely(path[depth].p_hdr == NULL)) {
2565                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2566                 return -EFSCORRUPTED;
2567         }
2568         /* find where to start removing */
2569         ex = path[depth].p_ext;
2570         if (!ex)
2571                 ex = EXT_LAST_EXTENT(eh);
2572
2573         ex_ee_block = le32_to_cpu(ex->ee_block);
2574         ex_ee_len = ext4_ext_get_actual_len(ex);
2575
2576         trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2577
2578         while (ex >= EXT_FIRST_EXTENT(eh) &&
2579                         ex_ee_block + ex_ee_len > start) {
2580
2581                 if (ext4_ext_is_unwritten(ex))
2582                         unwritten = 1;
2583                 else
2584                         unwritten = 0;
2585
2586                 ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
2587                           unwritten, ex_ee_len);
2588                 path[depth].p_ext = ex;
2589
2590                 a = ex_ee_block > start ? ex_ee_block : start;
2591                 b = ex_ee_block+ex_ee_len - 1 < end ?
2592                         ex_ee_block+ex_ee_len - 1 : end;
2593
2594                 ext_debug(inode, "  border %u:%u\n", a, b);
2595
2596                 /* If this extent is beyond the end of the hole, skip it */
2597                 if (end < ex_ee_block) {
2598                         /*
2599                          * We're going to skip this extent and move to another,
2600                          * so note that its first cluster is in use to avoid
2601                          * freeing it when removing blocks.  Eventually, the
2602                          * right edge of the truncated/punched region will
2603                          * be just to the left.
2604                          */
2605                         if (sbi->s_cluster_ratio > 1) {
2606                                 pblk = ext4_ext_pblock(ex);
2607                                 partial->pclu = EXT4_B2C(sbi, pblk);
2608                                 partial->state = nofree;
2609                         }
2610                         ex--;
2611                         ex_ee_block = le32_to_cpu(ex->ee_block);
2612                         ex_ee_len = ext4_ext_get_actual_len(ex);
2613                         continue;
2614                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2615                         EXT4_ERROR_INODE(inode,
2616                                          "can not handle truncate %u:%u "
2617                                          "on extent %u:%u",
2618                                          start, end, ex_ee_block,
2619                                          ex_ee_block + ex_ee_len - 1);
2620                         err = -EFSCORRUPTED;
2621                         goto out;
2622                 } else if (a != ex_ee_block) {
2623                         /* remove tail of the extent */
2624                         num = a - ex_ee_block;
2625                 } else {
2626                         /* remove whole extent: excellent! */
2627                         num = 0;
2628                 }
2629                 /*
2630                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2631                  * descriptor) for each block group; assume two block
2632                  * groups plus ex_ee_len/blocks_per_block_group for
2633                  * the worst case
2634                  */
2635                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2636                 if (ex == EXT_FIRST_EXTENT(eh)) {
2637                         correct_index = 1;
2638                         credits += (ext_depth(inode)) + 1;
2639                 }
2640                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2641                 /*
2642                  * We may end up freeing some index blocks and data from the
2643                  * punched range. Note that partial clusters are accounted for
2644                  * by ext4_free_data_revoke_credits().
2645                  */
2646                 revoke_credits =
2647                         ext4_free_metadata_revoke_credits(inode->i_sb,
2648                                                           ext_depth(inode)) +
2649                         ext4_free_data_revoke_credits(inode, b - a + 1);
2650
2651                 err = ext4_datasem_ensure_credits(handle, inode, credits,
2652                                                   credits, revoke_credits);
2653                 if (err) {
2654                         if (err > 0)
2655                                 err = -EAGAIN;
2656                         goto out;
2657                 }
2658
2659                 err = ext4_ext_get_access(handle, inode, path + depth);
2660                 if (err)
2661                         goto out;
2662
2663                 err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2664                 if (err)
2665                         goto out;
2666
2667                 if (num == 0)
2668                         /* this extent is removed; mark slot entirely unused */
2669                         ext4_ext_store_pblock(ex, 0);
2670
2671                 ex->ee_len = cpu_to_le16(num);
2672                 /*
2673                  * Do not mark unwritten if all the blocks in the
2674                  * extent have been removed.
2675                  */
2676                 if (unwritten && num)
2677                         ext4_ext_mark_unwritten(ex);
2678                 /*
2679                  * If the extent was completely released,
2680                  * we need to remove it from the leaf
2681                  */
2682                 if (num == 0) {
2683                         if (end != EXT_MAX_BLOCKS - 1) {
2684                                 /*
2685                                  * For hole punching, we need to scoot all the
2686                                  * extents up when an extent is removed so that
2687                                  * we dont have blank extents in the middle
2688                                  */
2689                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2690                                         sizeof(struct ext4_extent));
2691
2692                                 /* Now get rid of the one at the end */
2693                                 memset(EXT_LAST_EXTENT(eh), 0,
2694                                         sizeof(struct ext4_extent));
2695                         }
2696                         le16_add_cpu(&eh->eh_entries, -1);
2697                 }
2698
2699                 err = ext4_ext_dirty(handle, inode, path + depth);
2700                 if (err)
2701                         goto out;
2702
2703                 ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
2704                                 ext4_ext_pblock(ex));
2705                 ex--;
2706                 ex_ee_block = le32_to_cpu(ex->ee_block);
2707                 ex_ee_len = ext4_ext_get_actual_len(ex);
2708         }
2709
2710         if (correct_index && eh->eh_entries)
2711                 err = ext4_ext_correct_indexes(handle, inode, path);
2712
2713         /*
2714          * If there's a partial cluster and at least one extent remains in
2715          * the leaf, free the partial cluster if it isn't shared with the
2716          * current extent.  If it is shared with the current extent
2717          * we reset the partial cluster because we've reached the start of the
2718          * truncated/punched region and we're done removing blocks.
2719          */
2720         if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2721                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2722                 if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2723                         int flags = get_default_free_blocks_flags(inode);
2724
2725                         if (ext4_is_pending(inode, partial->lblk))
2726                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2727                         ext4_free_blocks(handle, inode, NULL,
2728                                          EXT4_C2B(sbi, partial->pclu),
2729                                          sbi->s_cluster_ratio, flags);
2730                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2731                                 ext4_rereserve_cluster(inode, partial->lblk);
2732                 }
2733                 partial->state = initial;
2734         }
2735
2736         /* if this leaf is free, then we should
2737          * remove it from index block above */
2738         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2739                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2740
2741 out:
2742         return err;
2743 }
2744
2745 /*
2746  * ext4_ext_more_to_rm:
2747  * returns 1 if current index has to be freed (even partial)
2748  */
2749 static int
2750 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2751 {
2752         BUG_ON(path->p_idx == NULL);
2753
2754         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2755                 return 0;
2756
2757         /*
2758          * if truncate on deeper level happened, it wasn't partial,
2759          * so we have to consider current index for truncation
2760          */
2761         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2762                 return 0;
2763         return 1;
2764 }
2765
2766 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2767                           ext4_lblk_t end)
2768 {
2769         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2770         int depth = ext_depth(inode);
2771         struct ext4_ext_path *path = NULL;
2772         struct partial_cluster partial;
2773         handle_t *handle;
2774         int i = 0, err = 0;
2775
2776         partial.pclu = 0;
2777         partial.lblk = 0;
2778         partial.state = initial;
2779
2780         ext_debug(inode, "truncate since %u to %u\n", start, end);
2781
2782         /* probably first extent we're gonna free will be last in block */
2783         handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2784                         depth + 1,
2785                         ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2786         if (IS_ERR(handle))
2787                 return PTR_ERR(handle);
2788
2789 again:
2790         trace_ext4_ext_remove_space(inode, start, end, depth);
2791
2792         /*
2793          * Check if we are removing extents inside the extent tree. If that
2794          * is the case, we are going to punch a hole inside the extent tree
2795          * so we have to check whether we need to split the extent covering
2796          * the last block to remove so we can easily remove the part of it
2797          * in ext4_ext_rm_leaf().
2798          */
2799         if (end < EXT_MAX_BLOCKS - 1) {
2800                 struct ext4_extent *ex;
2801                 ext4_lblk_t ee_block, ex_end, lblk;
2802                 ext4_fsblk_t pblk;
2803
2804                 /* find extent for or closest extent to this block */
2805                 path = ext4_find_extent(inode, end, NULL,
2806                                         EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
2807                 if (IS_ERR(path)) {
2808                         ext4_journal_stop(handle);
2809                         return PTR_ERR(path);
2810                 }
2811                 depth = ext_depth(inode);
2812                 /* Leaf not may not exist only if inode has no blocks at all */
2813                 ex = path[depth].p_ext;
2814                 if (!ex) {
2815                         if (depth) {
2816                                 EXT4_ERROR_INODE(inode,
2817                                                  "path[%d].p_hdr == NULL",
2818                                                  depth);
2819                                 err = -EFSCORRUPTED;
2820                         }
2821                         goto out;
2822                 }
2823
2824                 ee_block = le32_to_cpu(ex->ee_block);
2825                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2826
2827                 /*
2828                  * See if the last block is inside the extent, if so split
2829                  * the extent at 'end' block so we can easily remove the
2830                  * tail of the first part of the split extent in
2831                  * ext4_ext_rm_leaf().
2832                  */
2833                 if (end >= ee_block && end < ex_end) {
2834
2835                         /*
2836                          * If we're going to split the extent, note that
2837                          * the cluster containing the block after 'end' is
2838                          * in use to avoid freeing it when removing blocks.
2839                          */
2840                         if (sbi->s_cluster_ratio > 1) {
2841                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
2842                                 partial.pclu = EXT4_B2C(sbi, pblk);
2843                                 partial.state = nofree;
2844                         }
2845
2846                         /*
2847                          * Split the extent in two so that 'end' is the last
2848                          * block in the first new extent. Also we should not
2849                          * fail removing space due to ENOSPC so try to use
2850                          * reserved block if that happens.
2851                          */
2852                         err = ext4_force_split_extent_at(handle, inode, &path,
2853                                                          end + 1, 1);
2854                         if (err < 0)
2855                                 goto out;
2856
2857                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
2858                            partial.state == initial) {
2859                         /*
2860                          * If we're punching, there's an extent to the right.
2861                          * If the partial cluster hasn't been set, set it to
2862                          * that extent's first cluster and its state to nofree
2863                          * so it won't be freed should it contain blocks to be
2864                          * removed. If it's already set (tofree/nofree), we're
2865                          * retrying and keep the original partial cluster info
2866                          * so a cluster marked tofree as a result of earlier
2867                          * extent removal is not lost.
2868                          */
2869                         lblk = ex_end + 1;
2870                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2871                                                     &ex);
2872                         if (err)
2873                                 goto out;
2874                         if (pblk) {
2875                                 partial.pclu = EXT4_B2C(sbi, pblk);
2876                                 partial.state = nofree;
2877                         }
2878                 }
2879         }
2880         /*
2881          * We start scanning from right side, freeing all the blocks
2882          * after i_size and walking into the tree depth-wise.
2883          */
2884         depth = ext_depth(inode);
2885         if (path) {
2886                 int k = i = depth;
2887                 while (--k > 0)
2888                         path[k].p_block =
2889                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2890         } else {
2891                 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
2892                                GFP_NOFS | __GFP_NOFAIL);
2893                 if (path == NULL) {
2894                         ext4_journal_stop(handle);
2895                         return -ENOMEM;
2896                 }
2897                 path[0].p_maxdepth = path[0].p_depth = depth;
2898                 path[0].p_hdr = ext_inode_hdr(inode);
2899                 i = 0;
2900
2901                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2902                         err = -EFSCORRUPTED;
2903                         goto out;
2904                 }
2905         }
2906         err = 0;
2907
2908         while (i >= 0 && err == 0) {
2909                 if (i == depth) {
2910                         /* this is leaf block */
2911                         err = ext4_ext_rm_leaf(handle, inode, path,
2912                                                &partial, start, end);
2913                         /* root level has p_bh == NULL, brelse() eats this */
2914                         brelse(path[i].p_bh);
2915                         path[i].p_bh = NULL;
2916                         i--;
2917                         continue;
2918                 }
2919
2920                 /* this is index block */
2921                 if (!path[i].p_hdr) {
2922                         ext_debug(inode, "initialize header\n");
2923                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2924                 }
2925
2926                 if (!path[i].p_idx) {
2927                         /* this level hasn't been touched yet */
2928                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2929                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2930                         ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
2931                                   path[i].p_hdr,
2932                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2933                 } else {
2934                         /* we were already here, see at next index */
2935                         path[i].p_idx--;
2936                 }
2937
2938                 ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
2939                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2940                                 path[i].p_idx);
2941                 if (ext4_ext_more_to_rm(path + i)) {
2942                         struct buffer_head *bh;
2943                         /* go to the next level */
2944                         ext_debug(inode, "move to level %d (block %llu)\n",
2945                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2946                         memset(path + i + 1, 0, sizeof(*path));
2947                         bh = read_extent_tree_block(inode,
2948                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2949                                 EXT4_EX_NOCACHE);
2950                         if (IS_ERR(bh)) {
2951                                 /* should we reset i_size? */
2952                                 err = PTR_ERR(bh);
2953                                 break;
2954                         }
2955                         /* Yield here to deal with large extent trees.
2956                          * Should be a no-op if we did IO above. */
2957                         cond_resched();
2958                         if (WARN_ON(i + 1 > depth)) {
2959                                 err = -EFSCORRUPTED;
2960                                 break;
2961                         }
2962                         path[i + 1].p_bh = bh;
2963
2964                         /* save actual number of indexes since this
2965                          * number is changed at the next iteration */
2966                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2967                         i++;
2968                 } else {
2969                         /* we finished processing this index, go up */
2970                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2971                                 /* index is empty, remove it;
2972                                  * handle must be already prepared by the
2973                                  * truncatei_leaf() */
2974                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2975                         }
2976                         /* root level has p_bh == NULL, brelse() eats this */
2977                         brelse(path[i].p_bh);
2978                         path[i].p_bh = NULL;
2979                         i--;
2980                         ext_debug(inode, "return to level %d\n", i);
2981                 }
2982         }
2983
2984         trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
2985                                          path->p_hdr->eh_entries);
2986
2987         /*
2988          * if there's a partial cluster and we have removed the first extent
2989          * in the file, then we also free the partial cluster, if any
2990          */
2991         if (partial.state == tofree && err == 0) {
2992                 int flags = get_default_free_blocks_flags(inode);
2993
2994                 if (ext4_is_pending(inode, partial.lblk))
2995                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2996                 ext4_free_blocks(handle, inode, NULL,
2997                                  EXT4_C2B(sbi, partial.pclu),
2998                                  sbi->s_cluster_ratio, flags);
2999                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3000                         ext4_rereserve_cluster(inode, partial.lblk);
3001                 partial.state = initial;
3002         }
3003
3004         /* TODO: flexible tree reduction should be here */
3005         if (path->p_hdr->eh_entries == 0) {
3006                 /*
3007                  * truncate to zero freed all the tree,
3008                  * so we need to correct eh_depth
3009                  */
3010                 err = ext4_ext_get_access(handle, inode, path);
3011                 if (err == 0) {
3012                         ext_inode_hdr(inode)->eh_depth = 0;
3013                         ext_inode_hdr(inode)->eh_max =
3014                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3015                         err = ext4_ext_dirty(handle, inode, path);
3016                 }
3017         }
3018 out:
3019         ext4_ext_drop_refs(path);
3020         kfree(path);
3021         path = NULL;
3022         if (err == -EAGAIN)
3023                 goto again;
3024         ext4_journal_stop(handle);
3025
3026         return err;
3027 }
3028
3029 /*
3030  * called at mount time
3031  */
3032 void ext4_ext_init(struct super_block *sb)
3033 {
3034         /*
3035          * possible initialization would be here
3036          */
3037
3038         if (ext4_has_feature_extents(sb)) {
3039 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3040                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3041 #ifdef AGGRESSIVE_TEST
3042                        ", aggressive tests"
3043 #endif
3044 #ifdef CHECK_BINSEARCH
3045                        ", check binsearch"
3046 #endif
3047 #ifdef EXTENTS_STATS
3048                        ", stats"
3049 #endif
3050                        "\n");
3051 #endif
3052 #ifdef EXTENTS_STATS
3053                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3054                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3055                 EXT4_SB(sb)->s_ext_max = 0;
3056 #endif
3057         }
3058 }
3059
3060 /*
3061  * called at umount time
3062  */
3063 void ext4_ext_release(struct super_block *sb)
3064 {
3065         if (!ext4_has_feature_extents(sb))
3066                 return;
3067
3068 #ifdef EXTENTS_STATS
3069         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3070                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3071                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3072                         sbi->s_ext_blocks, sbi->s_ext_extents,
3073                         sbi->s_ext_blocks / sbi->s_ext_extents);
3074                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3075                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3076         }
3077 #endif
3078 }
3079
3080 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3081 {
3082         ext4_lblk_t  ee_block;
3083         ext4_fsblk_t ee_pblock;
3084         unsigned int ee_len;
3085
3086         ee_block  = le32_to_cpu(ex->ee_block);
3087         ee_len    = ext4_ext_get_actual_len(ex);
3088         ee_pblock = ext4_ext_pblock(ex);
3089
3090         if (ee_len == 0)
3091                 return 0;
3092
3093         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3094                                      EXTENT_STATUS_WRITTEN);
3095 }
3096
3097 /* FIXME!! we need to try to merge to left or right after zero-out  */
3098 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3099 {
3100         ext4_fsblk_t ee_pblock;
3101         unsigned int ee_len;
3102
3103         ee_len    = ext4_ext_get_actual_len(ex);
3104         ee_pblock = ext4_ext_pblock(ex);
3105         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3106                                   ee_len);
3107 }
3108
3109 /*
3110  * ext4_split_extent_at() splits an extent at given block.
3111  *
3112  * @handle: the journal handle
3113  * @inode: the file inode
3114  * @path: the path to the extent
3115  * @split: the logical block where the extent is splitted.
3116  * @split_flags: indicates if the extent could be zeroout if split fails, and
3117  *               the states(init or unwritten) of new extents.
3118  * @flags: flags used to insert new extent to extent tree.
3119  *
3120  *
3121  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3122  * of which are determined by split_flag.
3123  *
3124  * There are two cases:
3125  *  a> the extent are splitted into two extent.
3126  *  b> split is not needed, and just mark the extent.
3127  *
3128  * return 0 on success.
3129  */
3130 static int ext4_split_extent_at(handle_t *handle,
3131                              struct inode *inode,
3132                              struct ext4_ext_path **ppath,
3133                              ext4_lblk_t split,
3134                              int split_flag,
3135                              int flags)
3136 {
3137         struct ext4_ext_path *path = *ppath;
3138         ext4_fsblk_t newblock;
3139         ext4_lblk_t ee_block;
3140         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3141         struct ext4_extent *ex2 = NULL;
3142         unsigned int ee_len, depth;
3143         int err = 0;
3144
3145         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3146                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3147
3148         ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
3149
3150         ext4_ext_show_leaf(inode, path);
3151
3152         depth = ext_depth(inode);
3153         ex = path[depth].p_ext;
3154         ee_block = le32_to_cpu(ex->ee_block);
3155         ee_len = ext4_ext_get_actual_len(ex);
3156         newblock = split - ee_block + ext4_ext_pblock(ex);
3157
3158         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3159         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3160                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3161                              EXT4_EXT_MARK_UNWRIT1 |
3162                              EXT4_EXT_MARK_UNWRIT2));
3163
3164         err = ext4_ext_get_access(handle, inode, path + depth);
3165         if (err)
3166                 goto out;
3167
3168         if (split == ee_block) {
3169                 /*
3170                  * case b: block @split is the block that the extent begins with
3171                  * then we just change the state of the extent, and splitting
3172                  * is not needed.
3173                  */
3174                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3175                         ext4_ext_mark_unwritten(ex);
3176                 else
3177                         ext4_ext_mark_initialized(ex);
3178
3179                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3180                         ext4_ext_try_to_merge(handle, inode, path, ex);
3181
3182                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3183                 goto out;
3184         }
3185
3186         /* case a */
3187         memcpy(&orig_ex, ex, sizeof(orig_ex));
3188         ex->ee_len = cpu_to_le16(split - ee_block);
3189         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3190                 ext4_ext_mark_unwritten(ex);
3191
3192         /*
3193          * path may lead to new leaf, not to original leaf any more
3194          * after ext4_ext_insert_extent() returns,
3195          */
3196         err = ext4_ext_dirty(handle, inode, path + depth);
3197         if (err)
3198                 goto fix_extent_len;
3199
3200         ex2 = &newex;
3201         ex2->ee_block = cpu_to_le32(split);
3202         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3203         ext4_ext_store_pblock(ex2, newblock);
3204         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3205                 ext4_ext_mark_unwritten(ex2);
3206
3207         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3208         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3209                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3210                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3211                                 err = ext4_ext_zeroout(inode, ex2);
3212                                 zero_ex.ee_block = ex2->ee_block;
3213                                 zero_ex.ee_len = cpu_to_le16(
3214                                                 ext4_ext_get_actual_len(ex2));
3215                                 ext4_ext_store_pblock(&zero_ex,
3216                                                       ext4_ext_pblock(ex2));
3217                         } else {
3218                                 err = ext4_ext_zeroout(inode, ex);
3219                                 zero_ex.ee_block = ex->ee_block;
3220                                 zero_ex.ee_len = cpu_to_le16(
3221                                                 ext4_ext_get_actual_len(ex));
3222                                 ext4_ext_store_pblock(&zero_ex,
3223                                                       ext4_ext_pblock(ex));
3224                         }
3225                 } else {
3226                         err = ext4_ext_zeroout(inode, &orig_ex);
3227                         zero_ex.ee_block = orig_ex.ee_block;
3228                         zero_ex.ee_len = cpu_to_le16(
3229                                                 ext4_ext_get_actual_len(&orig_ex));
3230                         ext4_ext_store_pblock(&zero_ex,
3231                                               ext4_ext_pblock(&orig_ex));
3232                 }
3233
3234                 if (err)
3235                         goto fix_extent_len;
3236                 /* update the extent length and mark as initialized */
3237                 ex->ee_len = cpu_to_le16(ee_len);
3238                 ext4_ext_try_to_merge(handle, inode, path, ex);
3239                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3240                 if (err)
3241                         goto fix_extent_len;
3242
3243                 /* update extent status tree */
3244                 err = ext4_zeroout_es(inode, &zero_ex);
3245
3246                 goto out;
3247         } else if (err)
3248                 goto fix_extent_len;
3249
3250 out:
3251         ext4_ext_show_leaf(inode, path);
3252         return err;
3253
3254 fix_extent_len:
3255         ex->ee_len = orig_ex.ee_len;
3256         /*
3257          * Ignore ext4_ext_dirty return value since we are already in error path
3258          * and err is a non-zero error code.
3259          */
3260         ext4_ext_dirty(handle, inode, path + path->p_depth);
3261         return err;
3262 }
3263
3264 /*
3265  * ext4_split_extents() splits an extent and mark extent which is covered
3266  * by @map as split_flags indicates
3267  *
3268  * It may result in splitting the extent into multiple extents (up to three)
3269  * There are three possibilities:
3270  *   a> There is no split required
3271  *   b> Splits in two extents: Split is happening at either end of the extent
3272  *   c> Splits in three extents: Somone is splitting in middle of the extent
3273  *
3274  */
3275 static int ext4_split_extent(handle_t *handle,
3276                               struct inode *inode,
3277                               struct ext4_ext_path **ppath,
3278                               struct ext4_map_blocks *map,
3279                               int split_flag,
3280                               int flags)
3281 {
3282         struct ext4_ext_path *path = *ppath;
3283         ext4_lblk_t ee_block;
3284         struct ext4_extent *ex;
3285         unsigned int ee_len, depth;
3286         int err = 0;
3287         int unwritten;
3288         int split_flag1, flags1;
3289         int allocated = map->m_len;
3290
3291         depth = ext_depth(inode);
3292         ex = path[depth].p_ext;
3293         ee_block = le32_to_cpu(ex->ee_block);
3294         ee_len = ext4_ext_get_actual_len(ex);
3295         unwritten = ext4_ext_is_unwritten(ex);
3296
3297         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3298                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3299                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3300                 if (unwritten)
3301                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3302                                        EXT4_EXT_MARK_UNWRIT2;
3303                 if (split_flag & EXT4_EXT_DATA_VALID2)
3304                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3305                 err = ext4_split_extent_at(handle, inode, ppath,
3306                                 map->m_lblk + map->m_len, split_flag1, flags1);
3307                 if (err)
3308                         goto out;
3309         } else {
3310                 allocated = ee_len - (map->m_lblk - ee_block);
3311         }
3312         /*
3313          * Update path is required because previous ext4_split_extent_at() may
3314          * result in split of original leaf or extent zeroout.
3315          */
3316         path = ext4_find_extent(inode, map->m_lblk, ppath, flags);
3317         if (IS_ERR(path))
3318                 return PTR_ERR(path);
3319         depth = ext_depth(inode);
3320         ex = path[depth].p_ext;
3321         if (!ex) {
3322                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3323                                  (unsigned long) map->m_lblk);
3324                 return -EFSCORRUPTED;
3325         }
3326         unwritten = ext4_ext_is_unwritten(ex);
3327         split_flag1 = 0;
3328
3329         if (map->m_lblk >= ee_block) {
3330                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3331                 if (unwritten) {
3332                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3333                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3334                                                      EXT4_EXT_MARK_UNWRIT2);
3335                 }
3336                 err = ext4_split_extent_at(handle, inode, ppath,
3337                                 map->m_lblk, split_flag1, flags);
3338                 if (err)
3339                         goto out;
3340         }
3341
3342         ext4_ext_show_leaf(inode, path);
3343 out:
3344         return err ? err : allocated;
3345 }
3346
3347 /*
3348  * This function is called by ext4_ext_map_blocks() if someone tries to write
3349  * to an unwritten extent. It may result in splitting the unwritten
3350  * extent into multiple extents (up to three - one initialized and two
3351  * unwritten).
3352  * There are three possibilities:
3353  *   a> There is no split required: Entire extent should be initialized
3354  *   b> Splits in two extents: Write is happening at either end of the extent
3355  *   c> Splits in three extents: Somone is writing in middle of the extent
3356  *
3357  * Pre-conditions:
3358  *  - The extent pointed to by 'path' is unwritten.
3359  *  - The extent pointed to by 'path' contains a superset
3360  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3361  *
3362  * Post-conditions on success:
3363  *  - the returned value is the number of blocks beyond map->l_lblk
3364  *    that are allocated and initialized.
3365  *    It is guaranteed to be >= map->m_len.
3366  */
3367 static int ext4_ext_convert_to_initialized(handle_t *handle,
3368                                            struct inode *inode,
3369                                            struct ext4_map_blocks *map,
3370                                            struct ext4_ext_path **ppath,
3371                                            int flags)
3372 {
3373         struct ext4_ext_path *path = *ppath;
3374         struct ext4_sb_info *sbi;
3375         struct ext4_extent_header *eh;
3376         struct ext4_map_blocks split_map;
3377         struct ext4_extent zero_ex1, zero_ex2;
3378         struct ext4_extent *ex, *abut_ex;
3379         ext4_lblk_t ee_block, eof_block;
3380         unsigned int ee_len, depth, map_len = map->m_len;
3381         int allocated = 0, max_zeroout = 0;
3382         int err = 0;
3383         int split_flag = EXT4_EXT_DATA_VALID2;
3384
3385         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3386                   (unsigned long long)map->m_lblk, map_len);
3387
3388         sbi = EXT4_SB(inode->i_sb);
3389         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3390                         >> inode->i_sb->s_blocksize_bits;
3391         if (eof_block < map->m_lblk + map_len)
3392                 eof_block = map->m_lblk + map_len;
3393
3394         depth = ext_depth(inode);
3395         eh = path[depth].p_hdr;
3396         ex = path[depth].p_ext;
3397         ee_block = le32_to_cpu(ex->ee_block);
3398         ee_len = ext4_ext_get_actual_len(ex);
3399         zero_ex1.ee_len = 0;
3400         zero_ex2.ee_len = 0;
3401
3402         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3403
3404         /* Pre-conditions */
3405         BUG_ON(!ext4_ext_is_unwritten(ex));
3406         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3407
3408         /*
3409          * Attempt to transfer newly initialized blocks from the currently
3410          * unwritten extent to its neighbor. This is much cheaper
3411          * than an insertion followed by a merge as those involve costly
3412          * memmove() calls. Transferring to the left is the common case in
3413          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3414          * followed by append writes.
3415          *
3416          * Limitations of the current logic:
3417          *  - L1: we do not deal with writes covering the whole extent.
3418          *    This would require removing the extent if the transfer
3419          *    is possible.
3420          *  - L2: we only attempt to merge with an extent stored in the
3421          *    same extent tree node.
3422          */
3423         if ((map->m_lblk == ee_block) &&
3424                 /* See if we can merge left */
3425                 (map_len < ee_len) &&           /*L1*/
3426                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3427                 ext4_lblk_t prev_lblk;
3428                 ext4_fsblk_t prev_pblk, ee_pblk;
3429                 unsigned int prev_len;
3430
3431                 abut_ex = ex - 1;
3432                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3433                 prev_len = ext4_ext_get_actual_len(abut_ex);
3434                 prev_pblk = ext4_ext_pblock(abut_ex);
3435                 ee_pblk = ext4_ext_pblock(ex);
3436
3437                 /*
3438                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3439                  * upon those conditions:
3440                  * - C1: abut_ex is initialized,
3441                  * - C2: abut_ex is logically abutting ex,
3442                  * - C3: abut_ex is physically abutting ex,
3443                  * - C4: abut_ex can receive the additional blocks without
3444                  *   overflowing the (initialized) length limit.
3445                  */
3446                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3447                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3448                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3449                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3450                         err = ext4_ext_get_access(handle, inode, path + depth);
3451                         if (err)
3452                                 goto out;
3453
3454                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3455                                 map, ex, abut_ex);
3456
3457                         /* Shift the start of ex by 'map_len' blocks */
3458                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3459                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3460                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3461                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3462
3463                         /* Extend abut_ex by 'map_len' blocks */
3464                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3465
3466                         /* Result: number of initialized blocks past m_lblk */
3467                         allocated = map_len;
3468                 }
3469         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3470                    (map_len < ee_len) &&        /*L1*/
3471                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3472                 /* See if we can merge right */
3473                 ext4_lblk_t next_lblk;
3474                 ext4_fsblk_t next_pblk, ee_pblk;
3475                 unsigned int next_len;
3476
3477                 abut_ex = ex + 1;
3478                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3479                 next_len = ext4_ext_get_actual_len(abut_ex);
3480                 next_pblk = ext4_ext_pblock(abut_ex);
3481                 ee_pblk = ext4_ext_pblock(ex);
3482
3483                 /*
3484                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3485                  * upon those conditions:
3486                  * - C1: abut_ex is initialized,
3487                  * - C2: abut_ex is logically abutting ex,
3488                  * - C3: abut_ex is physically abutting ex,
3489                  * - C4: abut_ex can receive the additional blocks without
3490                  *   overflowing the (initialized) length limit.
3491                  */
3492                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3493                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3494                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3495                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3496                         err = ext4_ext_get_access(handle, inode, path + depth);
3497                         if (err)
3498                                 goto out;
3499
3500                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3501                                 map, ex, abut_ex);
3502
3503                         /* Shift the start of abut_ex by 'map_len' blocks */
3504                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3505                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3506                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3507                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3508
3509                         /* Extend abut_ex by 'map_len' blocks */
3510                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3511
3512                         /* Result: number of initialized blocks past m_lblk */
3513                         allocated = map_len;
3514                 }
3515         }
3516         if (allocated) {
3517                 /* Mark the block containing both extents as dirty */
3518                 err = ext4_ext_dirty(handle, inode, path + depth);
3519
3520                 /* Update path to point to the right extent */
3521                 path[depth].p_ext = abut_ex;
3522                 goto out;
3523         } else
3524                 allocated = ee_len - (map->m_lblk - ee_block);
3525
3526         WARN_ON(map->m_lblk < ee_block);
3527         /*
3528          * It is safe to convert extent to initialized via explicit
3529          * zeroout only if extent is fully inside i_size or new_size.
3530          */
3531         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3532
3533         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3534                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3535                         (inode->i_sb->s_blocksize_bits - 10);
3536
3537         /*
3538          * five cases:
3539          * 1. split the extent into three extents.
3540          * 2. split the extent into two extents, zeroout the head of the first
3541          *    extent.
3542          * 3. split the extent into two extents, zeroout the tail of the second
3543          *    extent.
3544          * 4. split the extent into two extents with out zeroout.
3545          * 5. no splitting needed, just possibly zeroout the head and / or the
3546          *    tail of the extent.
3547          */
3548         split_map.m_lblk = map->m_lblk;
3549         split_map.m_len = map->m_len;
3550
3551         if (max_zeroout && (allocated > split_map.m_len)) {
3552                 if (allocated <= max_zeroout) {
3553                         /* case 3 or 5 */
3554                         zero_ex1.ee_block =
3555                                  cpu_to_le32(split_map.m_lblk +
3556                                              split_map.m_len);
3557                         zero_ex1.ee_len =
3558                                 cpu_to_le16(allocated - split_map.m_len);
3559                         ext4_ext_store_pblock(&zero_ex1,
3560                                 ext4_ext_pblock(ex) + split_map.m_lblk +
3561                                 split_map.m_len - ee_block);
3562                         err = ext4_ext_zeroout(inode, &zero_ex1);
3563                         if (err)
3564                                 goto out;
3565                         split_map.m_len = allocated;
3566                 }
3567                 if (split_map.m_lblk - ee_block + split_map.m_len <
3568                                                                 max_zeroout) {
3569                         /* case 2 or 5 */
3570                         if (split_map.m_lblk != ee_block) {
3571                                 zero_ex2.ee_block = ex->ee_block;
3572                                 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3573                                                         ee_block);
3574                                 ext4_ext_store_pblock(&zero_ex2,
3575                                                       ext4_ext_pblock(ex));
3576                                 err = ext4_ext_zeroout(inode, &zero_ex2);
3577                                 if (err)
3578                                         goto out;
3579                         }
3580
3581                         split_map.m_len += split_map.m_lblk - ee_block;
3582                         split_map.m_lblk = ee_block;
3583                         allocated = map->m_len;
3584                 }
3585         }
3586
3587         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3588                                 flags);
3589         if (err > 0)
3590                 err = 0;
3591 out:
3592         /* If we have gotten a failure, don't zero out status tree */
3593         if (!err) {
3594                 err = ext4_zeroout_es(inode, &zero_ex1);
3595                 if (!err)
3596                         err = ext4_zeroout_es(inode, &zero_ex2);
3597         }
3598         return err ? err : allocated;
3599 }
3600
3601 /*
3602  * This function is called by ext4_ext_map_blocks() from
3603  * ext4_get_blocks_dio_write() when DIO to write
3604  * to an unwritten extent.
3605  *
3606  * Writing to an unwritten extent may result in splitting the unwritten
3607  * extent into multiple initialized/unwritten extents (up to three)
3608  * There are three possibilities:
3609  *   a> There is no split required: Entire extent should be unwritten
3610  *   b> Splits in two extents: Write is happening at either end of the extent
3611  *   c> Splits in three extents: Somone is writing in middle of the extent
3612  *
3613  * This works the same way in the case of initialized -> unwritten conversion.
3614  *
3615  * One of more index blocks maybe needed if the extent tree grow after
3616  * the unwritten extent split. To prevent ENOSPC occur at the IO
3617  * complete, we need to split the unwritten extent before DIO submit
3618  * the IO. The unwritten extent called at this time will be split
3619  * into three unwritten extent(at most). After IO complete, the part
3620  * being filled will be convert to initialized by the end_io callback function
3621  * via ext4_convert_unwritten_extents().
3622  *
3623  * Returns the size of unwritten extent to be written on success.
3624  */
3625 static int ext4_split_convert_extents(handle_t *handle,
3626                                         struct inode *inode,
3627                                         struct ext4_map_blocks *map,
3628                                         struct ext4_ext_path **ppath,
3629                                         int flags)
3630 {
3631         struct ext4_ext_path *path = *ppath;
3632         ext4_lblk_t eof_block;
3633         ext4_lblk_t ee_block;
3634         struct ext4_extent *ex;
3635         unsigned int ee_len;
3636         int split_flag = 0, depth;
3637
3638         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3639                   (unsigned long long)map->m_lblk, map->m_len);
3640
3641         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3642                         >> inode->i_sb->s_blocksize_bits;
3643         if (eof_block < map->m_lblk + map->m_len)
3644                 eof_block = map->m_lblk + map->m_len;
3645         /*
3646          * It is safe to convert extent to initialized via explicit
3647          * zeroout only if extent is fully inside i_size or new_size.
3648          */
3649         depth = ext_depth(inode);
3650         ex = path[depth].p_ext;
3651         ee_block = le32_to_cpu(ex->ee_block);
3652         ee_len = ext4_ext_get_actual_len(ex);
3653
3654         /* Convert to unwritten */
3655         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3656                 split_flag |= EXT4_EXT_DATA_VALID1;
3657         /* Convert to initialized */
3658         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3659                 split_flag |= ee_block + ee_len <= eof_block ?
3660                               EXT4_EXT_MAY_ZEROOUT : 0;
3661                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3662         }
3663         flags |= EXT4_GET_BLOCKS_PRE_IO;
3664         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3665 }
3666
3667 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3668                                                 struct inode *inode,
3669                                                 struct ext4_map_blocks *map,
3670                                                 struct ext4_ext_path **ppath)
3671 {
3672         struct ext4_ext_path *path = *ppath;
3673         struct ext4_extent *ex;
3674         ext4_lblk_t ee_block;
3675         unsigned int ee_len;
3676         int depth;
3677         int err = 0;
3678
3679         depth = ext_depth(inode);
3680         ex = path[depth].p_ext;
3681         ee_block = le32_to_cpu(ex->ee_block);
3682         ee_len = ext4_ext_get_actual_len(ex);
3683
3684         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3685                   (unsigned long long)ee_block, ee_len);
3686
3687         /* If extent is larger than requested it is a clear sign that we still
3688          * have some extent state machine issues left. So extent_split is still
3689          * required.
3690          * TODO: Once all related issues will be fixed this situation should be
3691          * illegal.
3692          */
3693         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3694 #ifdef CONFIG_EXT4_DEBUG
3695                 ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3696                              " len %u; IO logical block %llu, len %u",
3697                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3698                              (unsigned long long)map->m_lblk, map->m_len);
3699 #endif
3700                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3701                                                  EXT4_GET_BLOCKS_CONVERT);
3702                 if (err < 0)
3703                         return err;
3704                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3705                 if (IS_ERR(path))
3706                         return PTR_ERR(path);
3707                 depth = ext_depth(inode);
3708                 ex = path[depth].p_ext;
3709         }
3710
3711         err = ext4_ext_get_access(handle, inode, path + depth);
3712         if (err)
3713                 goto out;
3714         /* first mark the extent as initialized */
3715         ext4_ext_mark_initialized(ex);
3716
3717         /* note: ext4_ext_correct_indexes() isn't needed here because
3718          * borders are not changed
3719          */
3720         ext4_ext_try_to_merge(handle, inode, path, ex);
3721
3722         /* Mark modified extent as dirty */
3723         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3724 out:
3725         ext4_ext_show_leaf(inode, path);
3726         ext4_fc_track_range(inode, ee_block, ee_block + ee_len - 1);
3727         return err;
3728 }
3729
3730 static int
3731 convert_initialized_extent(handle_t *handle, struct inode *inode,
3732                            struct ext4_map_blocks *map,
3733                            struct ext4_ext_path **ppath,
3734                            unsigned int *allocated)
3735 {
3736         struct ext4_ext_path *path = *ppath;
3737         struct ext4_extent *ex;
3738         ext4_lblk_t ee_block;
3739         unsigned int ee_len;
3740         int depth;
3741         int err = 0;
3742
3743         /*
3744          * Make sure that the extent is no bigger than we support with
3745          * unwritten extent
3746          */
3747         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3748                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3749
3750         depth = ext_depth(inode);
3751         ex = path[depth].p_ext;
3752         ee_block = le32_to_cpu(ex->ee_block);
3753         ee_len = ext4_ext_get_actual_len(ex);
3754
3755         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3756                   (unsigned long long)ee_block, ee_len);
3757
3758         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3759                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3760                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3761                 if (err < 0)
3762                         return err;
3763                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3764                 if (IS_ERR(path))
3765                         return PTR_ERR(path);
3766                 depth = ext_depth(inode);
3767                 ex = path[depth].p_ext;
3768                 if (!ex) {
3769                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3770                                          (unsigned long) map->m_lblk);
3771                         return -EFSCORRUPTED;
3772                 }
3773         }
3774
3775         err = ext4_ext_get_access(handle, inode, path + depth);
3776         if (err)
3777                 return err;
3778         /* first mark the extent as unwritten */
3779         ext4_ext_mark_unwritten(ex);
3780
3781         /* note: ext4_ext_correct_indexes() isn't needed here because
3782          * borders are not changed
3783          */
3784         ext4_ext_try_to_merge(handle, inode, path, ex);
3785
3786         /* Mark modified extent as dirty */
3787         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3788         if (err)
3789                 return err;
3790         ext4_ext_show_leaf(inode, path);
3791
3792         ext4_update_inode_fsync_trans(handle, inode, 1);
3793
3794         map->m_flags |= EXT4_MAP_UNWRITTEN;
3795         if (*allocated > map->m_len)
3796                 *allocated = map->m_len;
3797         map->m_len = *allocated;
3798         ext4_fc_track_range(inode, ee_block, ee_block + ee_len - 1);
3799         return 0;
3800 }
3801
3802 static int
3803 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3804                         struct ext4_map_blocks *map,
3805                         struct ext4_ext_path **ppath, int flags,
3806                         unsigned int allocated, ext4_fsblk_t newblock)
3807 {
3808         struct ext4_ext_path __maybe_unused *path = *ppath;
3809         int ret = 0;
3810         int err = 0;
3811
3812         ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
3813                   (unsigned long long)map->m_lblk, map->m_len, flags,
3814                   allocated);
3815         ext4_ext_show_leaf(inode, path);
3816
3817         /*
3818          * When writing into unwritten space, we should not fail to
3819          * allocate metadata blocks for the new extent block if needed.
3820          */
3821         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3822
3823         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
3824                                                     allocated, newblock);
3825
3826         /* get_block() before submitting IO, split the extent */
3827         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
3828                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
3829                                          flags | EXT4_GET_BLOCKS_CONVERT);
3830                 if (ret < 0) {
3831                         err = ret;
3832                         goto out2;
3833                 }
3834                 /*
3835                  * shouldn't get a 0 return when splitting an extent unless
3836                  * m_len is 0 (bug) or extent has been corrupted
3837                  */
3838                 if (unlikely(ret == 0)) {
3839                         EXT4_ERROR_INODE(inode,
3840                                          "unexpected ret == 0, m_len = %u",
3841                                          map->m_len);
3842                         err = -EFSCORRUPTED;
3843                         goto out2;
3844                 }
3845                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3846                 goto out;
3847         }
3848         /* IO end_io complete, convert the filled extent to written */
3849         if (flags & EXT4_GET_BLOCKS_CONVERT) {
3850                 err = ext4_convert_unwritten_extents_endio(handle, inode, map,
3851                                                            ppath);
3852                 if (err < 0)
3853                         goto out2;
3854                 ext4_update_inode_fsync_trans(handle, inode, 1);
3855                 goto map_out;
3856         }
3857         /* buffered IO cases */
3858         /*
3859          * repeat fallocate creation request
3860          * we already have an unwritten extent
3861          */
3862         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
3863                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3864                 goto map_out;
3865         }
3866
3867         /* buffered READ or buffered write_begin() lookup */
3868         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3869                 /*
3870                  * We have blocks reserved already.  We
3871                  * return allocated blocks so that delalloc
3872                  * won't do block reservation for us.  But
3873                  * the buffer head will be unmapped so that
3874                  * a read from the block returns 0s.
3875                  */
3876                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3877                 goto out1;
3878         }
3879
3880         /*
3881          * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
3882          * For buffered writes, at writepage time, etc.  Convert a
3883          * discovered unwritten extent to written.
3884          */
3885         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
3886         if (ret < 0) {
3887                 err = ret;
3888                 goto out2;
3889         }
3890         ext4_update_inode_fsync_trans(handle, inode, 1);
3891         /*
3892          * shouldn't get a 0 return when converting an unwritten extent
3893          * unless m_len is 0 (bug) or extent has been corrupted
3894          */
3895         if (unlikely(ret == 0)) {
3896                 EXT4_ERROR_INODE(inode, "unexpected ret == 0, m_len = %u",
3897                                  map->m_len);
3898                 err = -EFSCORRUPTED;
3899                 goto out2;
3900         }
3901
3902 out:
3903         allocated = ret;
3904         map->m_flags |= EXT4_MAP_NEW;
3905 map_out:
3906         map->m_flags |= EXT4_MAP_MAPPED;
3907 out1:
3908         map->m_pblk = newblock;
3909         if (allocated > map->m_len)
3910                 allocated = map->m_len;
3911         map->m_len = allocated;
3912         ext4_ext_show_leaf(inode, path);
3913 out2:
3914         return err ? err : allocated;
3915 }
3916
3917 /*
3918  * get_implied_cluster_alloc - check to see if the requested
3919  * allocation (in the map structure) overlaps with a cluster already
3920  * allocated in an extent.
3921  *      @sb     The filesystem superblock structure
3922  *      @map    The requested lblk->pblk mapping
3923  *      @ex     The extent structure which might contain an implied
3924  *                      cluster allocation
3925  *
3926  * This function is called by ext4_ext_map_blocks() after we failed to
3927  * find blocks that were already in the inode's extent tree.  Hence,
3928  * we know that the beginning of the requested region cannot overlap
3929  * the extent from the inode's extent tree.  There are three cases we
3930  * want to catch.  The first is this case:
3931  *
3932  *               |--- cluster # N--|
3933  *    |--- extent ---|  |---- requested region ---|
3934  *                      |==========|
3935  *
3936  * The second case that we need to test for is this one:
3937  *
3938  *   |--------- cluster # N ----------------|
3939  *         |--- requested region --|   |------- extent ----|
3940  *         |=======================|
3941  *
3942  * The third case is when the requested region lies between two extents
3943  * within the same cluster:
3944  *          |------------- cluster # N-------------|
3945  * |----- ex -----|                  |---- ex_right ----|
3946  *                  |------ requested region ------|
3947  *                  |================|
3948  *
3949  * In each of the above cases, we need to set the map->m_pblk and
3950  * map->m_len so it corresponds to the return the extent labelled as
3951  * "|====|" from cluster #N, since it is already in use for data in
3952  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
3953  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
3954  * as a new "allocated" block region.  Otherwise, we will return 0 and
3955  * ext4_ext_map_blocks() will then allocate one or more new clusters
3956  * by calling ext4_mb_new_blocks().
3957  */
3958 static int get_implied_cluster_alloc(struct super_block *sb,
3959                                      struct ext4_map_blocks *map,
3960                                      struct ext4_extent *ex,
3961                                      struct ext4_ext_path *path)
3962 {
3963         struct ext4_sb_info *sbi = EXT4_SB(sb);
3964         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
3965         ext4_lblk_t ex_cluster_start, ex_cluster_end;
3966         ext4_lblk_t rr_cluster_start;
3967         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3968         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3969         unsigned short ee_len = ext4_ext_get_actual_len(ex);
3970
3971         /* The extent passed in that we are trying to match */
3972         ex_cluster_start = EXT4_B2C(sbi, ee_block);
3973         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
3974
3975         /* The requested region passed into ext4_map_blocks() */
3976         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
3977
3978         if ((rr_cluster_start == ex_cluster_end) ||
3979             (rr_cluster_start == ex_cluster_start)) {
3980                 if (rr_cluster_start == ex_cluster_end)
3981                         ee_start += ee_len - 1;
3982                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
3983                 map->m_len = min(map->m_len,
3984                                  (unsigned) sbi->s_cluster_ratio - c_offset);
3985                 /*
3986                  * Check for and handle this case:
3987                  *
3988                  *   |--------- cluster # N-------------|
3989                  *                     |------- extent ----|
3990                  *         |--- requested region ---|
3991                  *         |===========|
3992                  */
3993
3994                 if (map->m_lblk < ee_block)
3995                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
3996
3997                 /*
3998                  * Check for the case where there is already another allocated
3999                  * block to the right of 'ex' but before the end of the cluster.
4000                  *
4001                  *          |------------- cluster # N-------------|
4002                  * |----- ex -----|                  |---- ex_right ----|
4003                  *                  |------ requested region ------|
4004                  *                  |================|
4005                  */
4006                 if (map->m_lblk > ee_block) {
4007                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4008                         map->m_len = min(map->m_len, next - map->m_lblk);
4009                 }
4010
4011                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4012                 return 1;
4013         }
4014
4015         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4016         return 0;
4017 }
4018
4019
4020 /*
4021  * Block allocation/map/preallocation routine for extents based files
4022  *
4023  *
4024  * Need to be called with
4025  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4026  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4027  *
4028  * return > 0, number of blocks already mapped/allocated
4029  *          if create == 0 and these are pre-allocated blocks
4030  *              buffer head is unmapped
4031  *          otherwise blocks are mapped
4032  *
4033  * return = 0, if plain look up failed (blocks have not been allocated)
4034  *          buffer head is unmapped
4035  *
4036  * return < 0, error case.
4037  */
4038 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4039                         struct ext4_map_blocks *map, int flags)
4040 {
4041         struct ext4_ext_path *path = NULL;
4042         struct ext4_extent newex, *ex, *ex2;
4043         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4044         ext4_fsblk_t newblock = 0, pblk;
4045         int err = 0, depth, ret;
4046         unsigned int allocated = 0, offset = 0;
4047         unsigned int allocated_clusters = 0;
4048         struct ext4_allocation_request ar;
4049         ext4_lblk_t cluster_offset;
4050
4051         ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
4052         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4053
4054         /* find extent for this block */
4055         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4056         if (IS_ERR(path)) {
4057                 err = PTR_ERR(path);
4058                 path = NULL;
4059                 goto out;
4060         }
4061
4062         depth = ext_depth(inode);
4063
4064         /*
4065          * consistent leaf must not be empty;
4066          * this situation is possible, though, _during_ tree modification;
4067          * this is why assert can't be put in ext4_find_extent()
4068          */
4069         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4070                 EXT4_ERROR_INODE(inode, "bad extent address "
4071                                  "lblock: %lu, depth: %d pblock %lld",
4072                                  (unsigned long) map->m_lblk, depth,
4073                                  path[depth].p_block);
4074                 err = -EFSCORRUPTED;
4075                 goto out;
4076         }
4077
4078         ex = path[depth].p_ext;
4079         if (ex) {
4080                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4081                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4082                 unsigned short ee_len;
4083
4084
4085                 /*
4086                  * unwritten extents are treated as holes, except that
4087                  * we split out initialized portions during a write.
4088                  */
4089                 ee_len = ext4_ext_get_actual_len(ex);
4090
4091                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4092
4093                 /* if found extent covers block, simply return it */
4094                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4095                         newblock = map->m_lblk - ee_block + ee_start;
4096                         /* number of remaining blocks in the extent */
4097                         allocated = ee_len - (map->m_lblk - ee_block);
4098                         ext_debug(inode, "%u fit into %u:%d -> %llu\n",
4099                                   map->m_lblk, ee_block, ee_len, newblock);
4100
4101                         /*
4102                          * If the extent is initialized check whether the
4103                          * caller wants to convert it to unwritten.
4104                          */
4105                         if ((!ext4_ext_is_unwritten(ex)) &&
4106                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4107                                 err = convert_initialized_extent(handle,
4108                                         inode, map, &path, &allocated);
4109                                 goto out;
4110                         } else if (!ext4_ext_is_unwritten(ex)) {
4111                                 map->m_flags |= EXT4_MAP_MAPPED;
4112                                 map->m_pblk = newblock;
4113                                 if (allocated > map->m_len)
4114                                         allocated = map->m_len;
4115                                 map->m_len = allocated;
4116                                 ext4_ext_show_leaf(inode, path);
4117                                 goto out;
4118                         }
4119
4120                         ret = ext4_ext_handle_unwritten_extents(
4121                                 handle, inode, map, &path, flags,
4122                                 allocated, newblock);
4123                         if (ret < 0)
4124                                 err = ret;
4125                         else
4126                                 allocated = ret;
4127                         goto out;
4128                 }
4129         }
4130
4131         /*
4132          * requested block isn't allocated yet;
4133          * we couldn't try to create block if create flag is zero
4134          */
4135         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4136                 ext4_lblk_t hole_start, hole_len;
4137
4138                 hole_start = map->m_lblk;
4139                 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4140                 /*
4141                  * put just found gap into cache to speed up
4142                  * subsequent requests
4143                  */
4144                 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4145
4146                 /* Update hole_len to reflect hole size after map->m_lblk */
4147                 if (hole_start != map->m_lblk)
4148                         hole_len -= map->m_lblk - hole_start;
4149                 map->m_pblk = 0;
4150                 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4151
4152                 goto out;
4153         }
4154
4155         /*
4156          * Okay, we need to do block allocation.
4157          */
4158         newex.ee_block = cpu_to_le32(map->m_lblk);
4159         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4160
4161         /*
4162          * If we are doing bigalloc, check to see if the extent returned
4163          * by ext4_find_extent() implies a cluster we can use.
4164          */
4165         if (cluster_offset && ex &&
4166             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4167                 ar.len = allocated = map->m_len;
4168                 newblock = map->m_pblk;
4169                 goto got_allocated_blocks;
4170         }
4171
4172         /* find neighbour allocated blocks */
4173         ar.lleft = map->m_lblk;
4174         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4175         if (err)
4176                 goto out;
4177         ar.lright = map->m_lblk;
4178         ex2 = NULL;
4179         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4180         if (err)
4181                 goto out;
4182
4183         /* Check if the extent after searching to the right implies a
4184          * cluster we can use. */
4185         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4186             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4187                 ar.len = allocated = map->m_len;
4188                 newblock = map->m_pblk;
4189                 goto got_allocated_blocks;
4190         }
4191
4192         /*
4193          * See if request is beyond maximum number of blocks we can have in
4194          * a single extent. For an initialized extent this limit is
4195          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4196          * EXT_UNWRITTEN_MAX_LEN.
4197          */
4198         if (map->m_len > EXT_INIT_MAX_LEN &&
4199             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4200                 map->m_len = EXT_INIT_MAX_LEN;
4201         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4202                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4203                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4204
4205         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4206         newex.ee_len = cpu_to_le16(map->m_len);
4207         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4208         if (err)
4209                 allocated = ext4_ext_get_actual_len(&newex);
4210         else
4211                 allocated = map->m_len;
4212
4213         /* allocate new block */
4214         ar.inode = inode;
4215         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4216         ar.logical = map->m_lblk;
4217         /*
4218          * We calculate the offset from the beginning of the cluster
4219          * for the logical block number, since when we allocate a
4220          * physical cluster, the physical block should start at the
4221          * same offset from the beginning of the cluster.  This is
4222          * needed so that future calls to get_implied_cluster_alloc()
4223          * work correctly.
4224          */
4225         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4226         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4227         ar.goal -= offset;
4228         ar.logical -= offset;
4229         if (S_ISREG(inode->i_mode))
4230                 ar.flags = EXT4_MB_HINT_DATA;
4231         else
4232                 /* disable in-core preallocation for non-regular files */
4233                 ar.flags = 0;
4234         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4235                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4236         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4237                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4238         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4239                 ar.flags |= EXT4_MB_USE_RESERVED;
4240         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4241         if (!newblock)
4242                 goto out;
4243         allocated_clusters = ar.len;
4244         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4245         ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
4246                   ar.goal, newblock, ar.len, allocated);
4247         if (ar.len > allocated)
4248                 ar.len = allocated;
4249
4250 got_allocated_blocks:
4251         /* try to insert new extent into found leaf and return */
4252         pblk = newblock + offset;
4253         ext4_ext_store_pblock(&newex, pblk);
4254         newex.ee_len = cpu_to_le16(ar.len);
4255         /* Mark unwritten */
4256         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4257                 ext4_ext_mark_unwritten(&newex);
4258                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4259         }
4260
4261         err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags);
4262         if (err) {
4263                 if (allocated_clusters) {
4264                         int fb_flags = 0;
4265
4266                         /*
4267                          * free data blocks we just allocated.
4268                          * not a good idea to call discard here directly,
4269                          * but otherwise we'd need to call it every free().
4270                          */
4271                         ext4_discard_preallocations(inode, 0);
4272                         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4273                                 fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
4274                         ext4_free_blocks(handle, inode, NULL, newblock,
4275                                          EXT4_C2B(sbi, allocated_clusters),
4276                                          fb_flags);
4277                 }
4278                 goto out;
4279         }
4280
4281         /*
4282          * Reduce the reserved cluster count to reflect successful deferred
4283          * allocation of delayed allocated clusters or direct allocation of
4284          * clusters discovered to be delayed allocated.  Once allocated, a
4285          * cluster is not included in the reserved count.
4286          */
4287         if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
4288                 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4289                         /*
4290                          * When allocating delayed allocated clusters, simply
4291                          * reduce the reserved cluster count and claim quota
4292                          */
4293                         ext4_da_update_reserve_space(inode, allocated_clusters,
4294                                                         1);
4295                 } else {
4296                         ext4_lblk_t lblk, len;
4297                         unsigned int n;
4298
4299                         /*
4300                          * When allocating non-delayed allocated clusters
4301                          * (from fallocate, filemap, DIO, or clusters
4302                          * allocated when delalloc has been disabled by
4303                          * ext4_nonda_switch), reduce the reserved cluster
4304                          * count by the number of allocated clusters that
4305                          * have previously been delayed allocated.  Quota
4306                          * has been claimed by ext4_mb_new_blocks() above,
4307                          * so release the quota reservations made for any
4308                          * previously delayed allocated clusters.
4309                          */
4310                         lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4311                         len = allocated_clusters << sbi->s_cluster_bits;
4312                         n = ext4_es_delayed_clu(inode, lblk, len);
4313                         if (n > 0)
4314                                 ext4_da_update_reserve_space(inode, (int) n, 0);
4315                 }
4316         }
4317
4318         /*
4319          * Cache the extent and update transaction to commit on fdatasync only
4320          * when it is _not_ an unwritten extent.
4321          */
4322         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4323                 ext4_update_inode_fsync_trans(handle, inode, 1);
4324         else
4325                 ext4_update_inode_fsync_trans(handle, inode, 0);
4326
4327         map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
4328         map->m_pblk = pblk;
4329         map->m_len = ar.len;
4330         allocated = map->m_len;
4331         ext4_ext_show_leaf(inode, path);
4332         ext4_fc_track_range(inode, map->m_lblk, map->m_lblk + map->m_len - 1);
4333 out:
4334         ext4_ext_drop_refs(path);
4335         kfree(path);
4336
4337         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4338                                        err ? err : allocated);
4339         return err ? err : allocated;
4340 }
4341
4342 int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4343 {
4344         struct super_block *sb = inode->i_sb;
4345         ext4_lblk_t last_block;
4346         int err = 0;
4347
4348         /*
4349          * TODO: optimization is possible here.
4350          * Probably we need not scan at all,
4351          * because page truncation is enough.
4352          */
4353
4354         /* we have to know where to truncate from in crash case */
4355         EXT4_I(inode)->i_disksize = inode->i_size;
4356         err = ext4_mark_inode_dirty(handle, inode);
4357         if (err)
4358                 return err;
4359
4360         last_block = (inode->i_size + sb->s_blocksize - 1)
4361                         >> EXT4_BLOCK_SIZE_BITS(sb);
4362 retry:
4363         err = ext4_es_remove_extent(inode, last_block,
4364                                     EXT_MAX_BLOCKS - last_block);
4365         if (err == -ENOMEM) {
4366                 cond_resched();
4367                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4368                 goto retry;
4369         }
4370         if (err)
4371                 return err;
4372 retry_remove_space:
4373         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4374         if (err == -ENOMEM) {
4375                 cond_resched();
4376                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4377                 goto retry_remove_space;
4378         }
4379         return err;
4380 }
4381
4382 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4383                                   ext4_lblk_t len, loff_t new_size,
4384                                   int flags)
4385 {
4386         struct inode *inode = file_inode(file);
4387         handle_t *handle;
4388         int ret = 0;
4389         int ret2 = 0, ret3 = 0;
4390         int retries = 0;
4391         int depth = 0;
4392         struct ext4_map_blocks map;
4393         unsigned int credits;
4394         loff_t epos;
4395
4396         BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4397         map.m_lblk = offset;
4398         map.m_len = len;
4399         /*
4400          * Don't normalize the request if it can fit in one extent so
4401          * that it doesn't get unnecessarily split into multiple
4402          * extents.
4403          */
4404         if (len <= EXT_UNWRITTEN_MAX_LEN)
4405                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4406
4407         /*
4408          * credits to insert 1 extent into extent tree
4409          */
4410         credits = ext4_chunk_trans_blocks(inode, len);
4411         depth = ext_depth(inode);
4412
4413 retry:
4414         while (ret >= 0 && len) {
4415                 /*
4416                  * Recalculate credits when extent tree depth changes.
4417                  */
4418                 if (depth != ext_depth(inode)) {
4419                         credits = ext4_chunk_trans_blocks(inode, len);
4420                         depth = ext_depth(inode);
4421                 }
4422
4423                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4424                                             credits);
4425                 if (IS_ERR(handle)) {
4426                         ret = PTR_ERR(handle);
4427                         break;
4428                 }
4429                 ret = ext4_map_blocks(handle, inode, &map, flags);
4430                 if (ret <= 0) {
4431                         ext4_debug("inode #%lu: block %u: len %u: "
4432                                    "ext4_ext_map_blocks returned %d",
4433                                    inode->i_ino, map.m_lblk,
4434                                    map.m_len, ret);
4435                         ext4_mark_inode_dirty(handle, inode);
4436                         ret2 = ext4_journal_stop(handle);
4437                         break;
4438                 }
4439                 map.m_lblk += ret;
4440                 map.m_len = len = len - ret;
4441                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4442                 inode->i_ctime = current_time(inode);
4443                 if (new_size) {
4444                         if (epos > new_size)
4445                                 epos = new_size;
4446                         if (ext4_update_inode_size(inode, epos) & 0x1)
4447                                 inode->i_mtime = inode->i_ctime;
4448                 }
4449                 ret2 = ext4_mark_inode_dirty(handle, inode);
4450                 ext4_update_inode_fsync_trans(handle, inode, 1);
4451                 ret3 = ext4_journal_stop(handle);
4452                 ret2 = ret3 ? ret3 : ret2;
4453                 if (unlikely(ret2))
4454                         break;
4455         }
4456         if (ret == -ENOSPC &&
4457                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4458                 ret = 0;
4459                 goto retry;
4460         }
4461
4462         return ret > 0 ? ret2 : ret;
4463 }
4464
4465 static int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len);
4466
4467 static int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len);
4468
4469 static long ext4_zero_range(struct file *file, loff_t offset,
4470                             loff_t len, int mode)
4471 {
4472         struct inode *inode = file_inode(file);
4473         handle_t *handle = NULL;
4474         unsigned int max_blocks;
4475         loff_t new_size = 0;
4476         int ret = 0;
4477         int flags;
4478         int credits;
4479         int partial_begin, partial_end;
4480         loff_t start, end;
4481         ext4_lblk_t lblk;
4482         unsigned int blkbits = inode->i_blkbits;
4483
4484         trace_ext4_zero_range(inode, offset, len, mode);
4485
4486         /* Call ext4_force_commit to flush all data in case of data=journal. */
4487         if (ext4_should_journal_data(inode)) {
4488                 ret = ext4_force_commit(inode->i_sb);
4489                 if (ret)
4490                         return ret;
4491         }
4492
4493         /*
4494          * Round up offset. This is not fallocate, we need to zero out
4495          * blocks, so convert interior block aligned part of the range to
4496          * unwritten and possibly manually zero out unaligned parts of the
4497          * range.
4498          */
4499         start = round_up(offset, 1 << blkbits);
4500         end = round_down((offset + len), 1 << blkbits);
4501
4502         if (start < offset || end > offset + len)
4503                 return -EINVAL;
4504         partial_begin = offset & ((1 << blkbits) - 1);
4505         partial_end = (offset + len) & ((1 << blkbits) - 1);
4506
4507         lblk = start >> blkbits;
4508         max_blocks = (end >> blkbits);
4509         if (max_blocks < lblk)
4510                 max_blocks = 0;
4511         else
4512                 max_blocks -= lblk;
4513
4514         inode_lock(inode);
4515
4516         /*
4517          * Indirect files do not support unwritten extents
4518          */
4519         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4520                 ret = -EOPNOTSUPP;
4521                 goto out_mutex;
4522         }
4523
4524         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4525             (offset + len > inode->i_size ||
4526              offset + len > EXT4_I(inode)->i_disksize)) {
4527                 new_size = offset + len;
4528                 ret = inode_newsize_ok(inode, new_size);
4529                 if (ret)
4530                         goto out_mutex;
4531         }
4532
4533         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4534
4535         /* Wait all existing dio workers, newcomers will block on i_mutex */
4536         inode_dio_wait(inode);
4537
4538         /* Preallocate the range including the unaligned edges */
4539         if (partial_begin || partial_end) {
4540                 ret = ext4_alloc_file_blocks(file,
4541                                 round_down(offset, 1 << blkbits) >> blkbits,
4542                                 (round_up((offset + len), 1 << blkbits) -
4543                                  round_down(offset, 1 << blkbits)) >> blkbits,
4544                                 new_size, flags);
4545                 if (ret)
4546                         goto out_mutex;
4547
4548         }
4549
4550         /* Zero range excluding the unaligned edges */
4551         if (max_blocks > 0) {
4552                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4553                           EXT4_EX_NOCACHE);
4554
4555                 /*
4556                  * Prevent page faults from reinstantiating pages we have
4557                  * released from page cache.
4558                  */
4559                 down_write(&EXT4_I(inode)->i_mmap_sem);
4560
4561                 ret = ext4_break_layouts(inode);
4562                 if (ret) {
4563                         up_write(&EXT4_I(inode)->i_mmap_sem);
4564                         goto out_mutex;
4565                 }
4566
4567                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4568                 if (ret) {
4569                         up_write(&EXT4_I(inode)->i_mmap_sem);
4570                         goto out_mutex;
4571                 }
4572                 /* Now release the pages and zero block aligned part of pages */
4573                 truncate_pagecache_range(inode, start, end - 1);
4574                 inode->i_mtime = inode->i_ctime = current_time(inode);
4575
4576                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4577                                              flags);
4578                 up_write(&EXT4_I(inode)->i_mmap_sem);
4579                 if (ret)
4580                         goto out_mutex;
4581         }
4582         if (!partial_begin && !partial_end)
4583                 goto out_mutex;
4584
4585         /*
4586          * In worst case we have to writeout two nonadjacent unwritten
4587          * blocks and update the inode
4588          */
4589         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4590         if (ext4_should_journal_data(inode))
4591                 credits += 2;
4592         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4593         if (IS_ERR(handle)) {
4594                 ret = PTR_ERR(handle);
4595                 ext4_std_error(inode->i_sb, ret);
4596                 goto out_mutex;
4597         }
4598
4599         inode->i_mtime = inode->i_ctime = current_time(inode);
4600         if (new_size)
4601                 ext4_update_inode_size(inode, new_size);
4602         ret = ext4_mark_inode_dirty(handle, inode);
4603         if (unlikely(ret))
4604                 goto out_handle;
4605         ext4_fc_track_range(inode, offset >> inode->i_sb->s_blocksize_bits,
4606                         (offset + len - 1) >> inode->i_sb->s_blocksize_bits);
4607         /* Zero out partial block at the edges of the range */
4608         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4609         if (ret >= 0)
4610                 ext4_update_inode_fsync_trans(handle, inode, 1);
4611
4612         if (file->f_flags & O_SYNC)
4613                 ext4_handle_sync(handle);
4614
4615 out_handle:
4616         ext4_journal_stop(handle);
4617 out_mutex:
4618         inode_unlock(inode);
4619         return ret;
4620 }
4621
4622 /*
4623  * preallocate space for a file. This implements ext4's fallocate file
4624  * operation, which gets called from sys_fallocate system call.
4625  * For block-mapped files, posix_fallocate should fall back to the method
4626  * of writing zeroes to the required new blocks (the same behavior which is
4627  * expected for file systems which do not support fallocate() system call).
4628  */
4629 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4630 {
4631         struct inode *inode = file_inode(file);
4632         loff_t new_size = 0;
4633         unsigned int max_blocks;
4634         int ret = 0;
4635         int flags;
4636         ext4_lblk_t lblk;
4637         unsigned int blkbits = inode->i_blkbits;
4638
4639         /*
4640          * Encrypted inodes can't handle collapse range or insert
4641          * range since we would need to re-encrypt blocks with a
4642          * different IV or XTS tweak (which are based on the logical
4643          * block number).
4644          */
4645         if (IS_ENCRYPTED(inode) &&
4646             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
4647                 return -EOPNOTSUPP;
4648
4649         /* Return error if mode is not supported */
4650         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4651                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4652                      FALLOC_FL_INSERT_RANGE))
4653                 return -EOPNOTSUPP;
4654         ext4_fc_track_range(inode, offset >> blkbits,
4655                         (offset + len - 1) >> blkbits);
4656
4657         ext4_fc_start_update(inode);
4658
4659         if (mode & FALLOC_FL_PUNCH_HOLE) {
4660                 ret = ext4_punch_hole(inode, offset, len);
4661                 goto exit;
4662         }
4663
4664         ret = ext4_convert_inline_data(inode);
4665         if (ret)
4666                 goto exit;
4667
4668         if (mode & FALLOC_FL_COLLAPSE_RANGE) {
4669                 ret = ext4_collapse_range(inode, offset, len);
4670                 goto exit;
4671         }
4672
4673         if (mode & FALLOC_FL_INSERT_RANGE) {
4674                 ret = ext4_insert_range(inode, offset, len);
4675                 goto exit;
4676         }
4677
4678         if (mode & FALLOC_FL_ZERO_RANGE) {
4679                 ret = ext4_zero_range(file, offset, len, mode);
4680                 goto exit;
4681         }
4682         trace_ext4_fallocate_enter(inode, offset, len, mode);
4683         lblk = offset >> blkbits;
4684
4685         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4686         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4687
4688         inode_lock(inode);
4689
4690         /*
4691          * We only support preallocation for extent-based files only
4692          */
4693         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4694                 ret = -EOPNOTSUPP;
4695                 goto out;
4696         }
4697
4698         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4699             (offset + len > inode->i_size ||
4700              offset + len > EXT4_I(inode)->i_disksize)) {
4701                 new_size = offset + len;
4702                 ret = inode_newsize_ok(inode, new_size);
4703                 if (ret)
4704                         goto out;
4705         }
4706
4707         /* Wait all existing dio workers, newcomers will block on i_mutex */
4708         inode_dio_wait(inode);
4709
4710         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4711         if (ret)
4712                 goto out;
4713
4714         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4715                 ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
4716                                         EXT4_I(inode)->i_sync_tid);
4717         }
4718 out:
4719         inode_unlock(inode);
4720         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4721 exit:
4722         ext4_fc_stop_update(inode);
4723         return ret;
4724 }
4725
4726 /*
4727  * This function convert a range of blocks to written extents
4728  * The caller of this function will pass the start offset and the size.
4729  * all unwritten extents within this range will be converted to
4730  * written extents.
4731  *
4732  * This function is called from the direct IO end io call back
4733  * function, to convert the fallocated extents after IO is completed.
4734  * Returns 0 on success.
4735  */
4736 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4737                                    loff_t offset, ssize_t len)
4738 {
4739         unsigned int max_blocks;
4740         int ret = 0, ret2 = 0, ret3 = 0;
4741         struct ext4_map_blocks map;
4742         unsigned int blkbits = inode->i_blkbits;
4743         unsigned int credits = 0;
4744
4745         map.m_lblk = offset >> blkbits;
4746         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4747
4748         if (!handle) {
4749                 /*
4750                  * credits to insert 1 extent into extent tree
4751                  */
4752                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4753         }
4754         while (ret >= 0 && ret < max_blocks) {
4755                 map.m_lblk += ret;
4756                 map.m_len = (max_blocks -= ret);
4757                 if (credits) {
4758                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4759                                                     credits);
4760                         if (IS_ERR(handle)) {
4761                                 ret = PTR_ERR(handle);
4762                                 break;
4763                         }
4764                 }
4765                 ret = ext4_map_blocks(handle, inode, &map,
4766                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4767                 if (ret <= 0)
4768                         ext4_warning(inode->i_sb,
4769                                      "inode #%lu: block %u: len %u: "
4770                                      "ext4_ext_map_blocks returned %d",
4771                                      inode->i_ino, map.m_lblk,
4772                                      map.m_len, ret);
4773                 ret2 = ext4_mark_inode_dirty(handle, inode);
4774                 if (credits) {
4775                         ret3 = ext4_journal_stop(handle);
4776                         if (unlikely(ret3))
4777                                 ret2 = ret3;
4778                 }
4779
4780                 if (ret <= 0 || ret2)
4781                         break;
4782         }
4783         return ret > 0 ? ret2 : ret;
4784 }
4785
4786 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
4787 {
4788         int ret = 0, err = 0;
4789         struct ext4_io_end_vec *io_end_vec;
4790
4791         /*
4792          * This is somewhat ugly but the idea is clear: When transaction is
4793          * reserved, everything goes into it. Otherwise we rather start several
4794          * smaller transactions for conversion of each extent separately.
4795          */
4796         if (handle) {
4797                 handle = ext4_journal_start_reserved(handle,
4798                                                      EXT4_HT_EXT_CONVERT);
4799                 if (IS_ERR(handle))
4800                         return PTR_ERR(handle);
4801         }
4802
4803         list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4804                 ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4805                                                      io_end_vec->offset,
4806                                                      io_end_vec->size);
4807                 if (ret)
4808                         break;
4809         }
4810
4811         if (handle)
4812                 err = ext4_journal_stop(handle);
4813
4814         return ret < 0 ? ret : err;
4815 }
4816
4817 static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
4818 {
4819         __u64 physical = 0;
4820         __u64 length = 0;
4821         int blockbits = inode->i_sb->s_blocksize_bits;
4822         int error = 0;
4823         u16 iomap_type;
4824
4825         /* in-inode? */
4826         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4827                 struct ext4_iloc iloc;
4828                 int offset;     /* offset of xattr in inode */
4829
4830                 error = ext4_get_inode_loc(inode, &iloc);
4831                 if (error)
4832                         return error;
4833                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
4834                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4835                                 EXT4_I(inode)->i_extra_isize;
4836                 physical += offset;
4837                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4838                 brelse(iloc.bh);
4839                 iomap_type = IOMAP_INLINE;
4840         } else if (EXT4_I(inode)->i_file_acl) { /* external block */
4841                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4842                 length = inode->i_sb->s_blocksize;
4843                 iomap_type = IOMAP_MAPPED;
4844         } else {
4845                 /* no in-inode or external block for xattr, so return -ENOENT */
4846                 error = -ENOENT;
4847                 goto out;
4848         }
4849
4850         iomap->addr = physical;
4851         iomap->offset = 0;
4852         iomap->length = length;
4853         iomap->type = iomap_type;
4854         iomap->flags = 0;
4855 out:
4856         return error;
4857 }
4858
4859 static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
4860                                   loff_t length, unsigned flags,
4861                                   struct iomap *iomap, struct iomap *srcmap)
4862 {
4863         int error;
4864
4865         error = ext4_iomap_xattr_fiemap(inode, iomap);
4866         if (error == 0 && (offset >= iomap->length))
4867                 error = -ENOENT;
4868         return error;
4869 }
4870
4871 static const struct iomap_ops ext4_iomap_xattr_ops = {
4872         .iomap_begin            = ext4_iomap_xattr_begin,
4873 };
4874
4875 static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
4876 {
4877         u64 maxbytes;
4878
4879         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4880                 maxbytes = inode->i_sb->s_maxbytes;
4881         else
4882                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
4883
4884         if (*len == 0)
4885                 return -EINVAL;
4886         if (start > maxbytes)
4887                 return -EFBIG;
4888
4889         /*
4890          * Shrink request scope to what the fs can actually handle.
4891          */
4892         if (*len > maxbytes || (maxbytes - *len) < start)
4893                 *len = maxbytes - start;
4894         return 0;
4895 }
4896
4897 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4898                 u64 start, u64 len)
4899 {
4900         int error = 0;
4901
4902         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4903                 error = ext4_ext_precache(inode);
4904                 if (error)
4905                         return error;
4906                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4907         }
4908
4909         /*
4910          * For bitmap files the maximum size limit could be smaller than
4911          * s_maxbytes, so check len here manually instead of just relying on the
4912          * generic check.
4913          */
4914         error = ext4_fiemap_check_ranges(inode, start, &len);
4915         if (error)
4916                 return error;
4917
4918         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4919                 fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
4920                 return iomap_fiemap(inode, fieinfo, start, len,
4921                                     &ext4_iomap_xattr_ops);
4922         }
4923
4924         return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
4925 }
4926
4927 int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
4928                       __u64 start, __u64 len)
4929 {
4930         ext4_lblk_t start_blk, len_blks;
4931         __u64 last_blk;
4932         int error = 0;
4933
4934         if (ext4_has_inline_data(inode)) {
4935                 int has_inline;
4936
4937                 down_read(&EXT4_I(inode)->xattr_sem);
4938                 has_inline = ext4_has_inline_data(inode);
4939                 up_read(&EXT4_I(inode)->xattr_sem);
4940                 if (has_inline)
4941                         return 0;
4942         }
4943
4944         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4945                 error = ext4_ext_precache(inode);
4946                 if (error)
4947                         return error;
4948                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4949         }
4950
4951         error = fiemap_prep(inode, fieinfo, start, &len, 0);
4952         if (error)
4953                 return error;
4954
4955         error = ext4_fiemap_check_ranges(inode, start, &len);
4956         if (error)
4957                 return error;
4958
4959         start_blk = start >> inode->i_sb->s_blocksize_bits;
4960         last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
4961         if (last_blk >= EXT_MAX_BLOCKS)
4962                 last_blk = EXT_MAX_BLOCKS-1;
4963         len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
4964
4965         /*
4966          * Walk the extent tree gathering extent information
4967          * and pushing extents back to the user.
4968          */
4969         return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
4970 }
4971
4972 /*
4973  * ext4_access_path:
4974  * Function to access the path buffer for marking it dirty.
4975  * It also checks if there are sufficient credits left in the journal handle
4976  * to update path.
4977  */
4978 static int
4979 ext4_access_path(handle_t *handle, struct inode *inode,
4980                 struct ext4_ext_path *path)
4981 {
4982         int credits, err;
4983
4984         if (!ext4_handle_valid(handle))
4985                 return 0;
4986
4987         /*
4988          * Check if need to extend journal credits
4989          * 3 for leaf, sb, and inode plus 2 (bmap and group
4990          * descriptor) for each block group; assume two block
4991          * groups
4992          */
4993         credits = ext4_writepage_trans_blocks(inode);
4994         err = ext4_datasem_ensure_credits(handle, inode, 7, credits, 0);
4995         if (err < 0)
4996                 return err;
4997
4998         err = ext4_ext_get_access(handle, inode, path);
4999         return err;
5000 }
5001
5002 /*
5003  * ext4_ext_shift_path_extents:
5004  * Shift the extents of a path structure lying between path[depth].p_ext
5005  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5006  * if it is right shift or left shift operation.
5007  */
5008 static int
5009 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5010                             struct inode *inode, handle_t *handle,
5011                             enum SHIFT_DIRECTION SHIFT)
5012 {
5013         int depth, err = 0;
5014         struct ext4_extent *ex_start, *ex_last;
5015         bool update = false;
5016         depth = path->p_depth;
5017
5018         while (depth >= 0) {
5019                 if (depth == path->p_depth) {
5020                         ex_start = path[depth].p_ext;
5021                         if (!ex_start)
5022                                 return -EFSCORRUPTED;
5023
5024                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5025
5026                         err = ext4_access_path(handle, inode, path + depth);
5027                         if (err)
5028                                 goto out;
5029
5030                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5031                                 update = true;
5032
5033                         while (ex_start <= ex_last) {
5034                                 if (SHIFT == SHIFT_LEFT) {
5035                                         le32_add_cpu(&ex_start->ee_block,
5036                                                 -shift);
5037                                         /* Try to merge to the left. */
5038                                         if ((ex_start >
5039                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5040                                             &&
5041                                             ext4_ext_try_to_merge_right(inode,
5042                                             path, ex_start - 1))
5043                                                 ex_last--;
5044                                         else
5045                                                 ex_start++;
5046                                 } else {
5047                                         le32_add_cpu(&ex_last->ee_block, shift);
5048                                         ext4_ext_try_to_merge_right(inode, path,
5049                                                 ex_last);
5050                                         ex_last--;
5051                                 }
5052                         }
5053                         err = ext4_ext_dirty(handle, inode, path + depth);
5054                         if (err)
5055                                 goto out;
5056
5057                         if (--depth < 0 || !update)
5058                                 break;
5059                 }
5060
5061                 /* Update index too */
5062                 err = ext4_access_path(handle, inode, path + depth);
5063                 if (err)
5064                         goto out;
5065
5066                 if (SHIFT == SHIFT_LEFT)
5067                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5068                 else
5069                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5070                 err = ext4_ext_dirty(handle, inode, path + depth);
5071                 if (err)
5072                         goto out;
5073
5074                 /* we are done if current index is not a starting index */
5075                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5076                         break;
5077
5078                 depth--;
5079         }
5080
5081 out:
5082         return err;
5083 }
5084
5085 /*
5086  * ext4_ext_shift_extents:
5087  * All the extents which lies in the range from @start to the last allocated
5088  * block for the @inode are shifted either towards left or right (depending
5089  * upon @SHIFT) by @shift blocks.
5090  * On success, 0 is returned, error otherwise.
5091  */
5092 static int
5093 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5094                        ext4_lblk_t start, ext4_lblk_t shift,
5095                        enum SHIFT_DIRECTION SHIFT)
5096 {
5097         struct ext4_ext_path *path;
5098         int ret = 0, depth;
5099         struct ext4_extent *extent;
5100         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5101
5102         /* Let path point to the last extent */
5103         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5104                                 EXT4_EX_NOCACHE);
5105         if (IS_ERR(path))
5106                 return PTR_ERR(path);
5107
5108         depth = path->p_depth;
5109         extent = path[depth].p_ext;
5110         if (!extent)
5111                 goto out;
5112
5113         stop = le32_to_cpu(extent->ee_block);
5114
5115        /*
5116         * For left shifts, make sure the hole on the left is big enough to
5117         * accommodate the shift.  For right shifts, make sure the last extent
5118         * won't be shifted beyond EXT_MAX_BLOCKS.
5119         */
5120         if (SHIFT == SHIFT_LEFT) {
5121                 path = ext4_find_extent(inode, start - 1, &path,
5122                                         EXT4_EX_NOCACHE);
5123                 if (IS_ERR(path))
5124                         return PTR_ERR(path);
5125                 depth = path->p_depth;
5126                 extent =  path[depth].p_ext;
5127                 if (extent) {
5128                         ex_start = le32_to_cpu(extent->ee_block);
5129                         ex_end = le32_to_cpu(extent->ee_block) +
5130                                 ext4_ext_get_actual_len(extent);
5131                 } else {
5132                         ex_start = 0;
5133                         ex_end = 0;
5134                 }
5135
5136                 if ((start == ex_start && shift > ex_start) ||
5137                     (shift > start - ex_end)) {
5138                         ret = -EINVAL;
5139                         goto out;
5140                 }
5141         } else {
5142                 if (shift > EXT_MAX_BLOCKS -
5143                     (stop + ext4_ext_get_actual_len(extent))) {
5144                         ret = -EINVAL;
5145                         goto out;
5146                 }
5147         }
5148
5149         /*
5150          * In case of left shift, iterator points to start and it is increased
5151          * till we reach stop. In case of right shift, iterator points to stop
5152          * and it is decreased till we reach start.
5153          */
5154         if (SHIFT == SHIFT_LEFT)
5155                 iterator = &start;
5156         else
5157                 iterator = &stop;
5158
5159         /*
5160          * Its safe to start updating extents.  Start and stop are unsigned, so
5161          * in case of right shift if extent with 0 block is reached, iterator
5162          * becomes NULL to indicate the end of the loop.
5163          */
5164         while (iterator && start <= stop) {
5165                 path = ext4_find_extent(inode, *iterator, &path,
5166                                         EXT4_EX_NOCACHE);
5167                 if (IS_ERR(path))
5168                         return PTR_ERR(path);
5169                 depth = path->p_depth;
5170                 extent = path[depth].p_ext;
5171                 if (!extent) {
5172                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5173                                          (unsigned long) *iterator);
5174                         return -EFSCORRUPTED;
5175                 }
5176                 if (SHIFT == SHIFT_LEFT && *iterator >
5177                     le32_to_cpu(extent->ee_block)) {
5178                         /* Hole, move to the next extent */
5179                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5180                                 path[depth].p_ext++;
5181                         } else {
5182                                 *iterator = ext4_ext_next_allocated_block(path);
5183                                 continue;
5184                         }
5185                 }
5186
5187                 if (SHIFT == SHIFT_LEFT) {
5188                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5189                         *iterator = le32_to_cpu(extent->ee_block) +
5190                                         ext4_ext_get_actual_len(extent);
5191                 } else {
5192                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5193                         if (le32_to_cpu(extent->ee_block) > 0)
5194                                 *iterator = le32_to_cpu(extent->ee_block) - 1;
5195                         else
5196                                 /* Beginning is reached, end of the loop */
5197                                 iterator = NULL;
5198                         /* Update path extent in case we need to stop */
5199                         while (le32_to_cpu(extent->ee_block) < start)
5200                                 extent++;
5201                         path[depth].p_ext = extent;
5202                 }
5203                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5204                                 handle, SHIFT);
5205                 if (ret)
5206                         break;
5207         }
5208 out:
5209         ext4_ext_drop_refs(path);
5210         kfree(path);
5211         return ret;
5212 }
5213
5214 /*
5215  * ext4_collapse_range:
5216  * This implements the fallocate's collapse range functionality for ext4
5217  * Returns: 0 and non-zero on error.
5218  */
5219 static int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5220 {
5221         struct super_block *sb = inode->i_sb;
5222         ext4_lblk_t punch_start, punch_stop;
5223         handle_t *handle;
5224         unsigned int credits;
5225         loff_t new_size, ioffset;
5226         int ret;
5227
5228         /*
5229          * We need to test this early because xfstests assumes that a
5230          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5231          * system does not support collapse range.
5232          */
5233         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5234                 return -EOPNOTSUPP;
5235
5236         /* Collapse range works only on fs cluster size aligned regions. */
5237         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5238                 return -EINVAL;
5239
5240         trace_ext4_collapse_range(inode, offset, len);
5241
5242         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5243         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5244
5245         /* Call ext4_force_commit to flush all data in case of data=journal. */
5246         if (ext4_should_journal_data(inode)) {
5247                 ret = ext4_force_commit(inode->i_sb);
5248                 if (ret)
5249                         return ret;
5250         }
5251
5252         inode_lock(inode);
5253         /*
5254          * There is no need to overlap collapse range with EOF, in which case
5255          * it is effectively a truncate operation
5256          */
5257         if (offset + len >= inode->i_size) {
5258                 ret = -EINVAL;
5259                 goto out_mutex;
5260         }
5261
5262         /* Currently just for extent based files */
5263         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5264                 ret = -EOPNOTSUPP;
5265                 goto out_mutex;
5266         }
5267
5268         /* Wait for existing dio to complete */
5269         inode_dio_wait(inode);
5270
5271         /*
5272          * Prevent page faults from reinstantiating pages we have released from
5273          * page cache.
5274          */
5275         down_write(&EXT4_I(inode)->i_mmap_sem);
5276
5277         ret = ext4_break_layouts(inode);
5278         if (ret)
5279                 goto out_mmap;
5280
5281         /*
5282          * Need to round down offset to be aligned with page size boundary
5283          * for page size > block size.
5284          */
5285         ioffset = round_down(offset, PAGE_SIZE);
5286         /*
5287          * Write tail of the last page before removed range since it will get
5288          * removed from the page cache below.
5289          */
5290         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5291         if (ret)
5292                 goto out_mmap;
5293         /*
5294          * Write data that will be shifted to preserve them when discarding
5295          * page cache below. We are also protected from pages becoming dirty
5296          * by i_mmap_sem.
5297          */
5298         ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5299                                            LLONG_MAX);
5300         if (ret)
5301                 goto out_mmap;
5302         truncate_pagecache(inode, ioffset);
5303
5304         credits = ext4_writepage_trans_blocks(inode);
5305         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5306         if (IS_ERR(handle)) {
5307                 ret = PTR_ERR(handle);
5308                 goto out_mmap;
5309         }
5310         ext4_fc_start_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE);
5311
5312         down_write(&EXT4_I(inode)->i_data_sem);
5313         ext4_discard_preallocations(inode, 0);
5314
5315         ret = ext4_es_remove_extent(inode, punch_start,
5316                                     EXT_MAX_BLOCKS - punch_start);
5317         if (ret) {
5318                 up_write(&EXT4_I(inode)->i_data_sem);
5319                 goto out_stop;
5320         }
5321
5322         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5323         if (ret) {
5324                 up_write(&EXT4_I(inode)->i_data_sem);
5325                 goto out_stop;
5326         }
5327         ext4_discard_preallocations(inode, 0);
5328
5329         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5330                                      punch_stop - punch_start, SHIFT_LEFT);
5331         if (ret) {
5332                 up_write(&EXT4_I(inode)->i_data_sem);
5333                 goto out_stop;
5334         }
5335
5336         new_size = inode->i_size - len;
5337         i_size_write(inode, new_size);
5338         EXT4_I(inode)->i_disksize = new_size;
5339
5340         up_write(&EXT4_I(inode)->i_data_sem);
5341         if (IS_SYNC(inode))
5342                 ext4_handle_sync(handle);
5343         inode->i_mtime = inode->i_ctime = current_time(inode);
5344         ret = ext4_mark_inode_dirty(handle, inode);
5345         ext4_update_inode_fsync_trans(handle, inode, 1);
5346
5347 out_stop:
5348         ext4_journal_stop(handle);
5349         ext4_fc_stop_ineligible(sb);
5350 out_mmap:
5351         up_write(&EXT4_I(inode)->i_mmap_sem);
5352 out_mutex:
5353         inode_unlock(inode);
5354         return ret;
5355 }
5356
5357 /*
5358  * ext4_insert_range:
5359  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5360  * The data blocks starting from @offset to the EOF are shifted by @len
5361  * towards right to create a hole in the @inode. Inode size is increased
5362  * by len bytes.
5363  * Returns 0 on success, error otherwise.
5364  */
5365 static int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5366 {
5367         struct super_block *sb = inode->i_sb;
5368         handle_t *handle;
5369         struct ext4_ext_path *path;
5370         struct ext4_extent *extent;
5371         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5372         unsigned int credits, ee_len;
5373         int ret = 0, depth, split_flag = 0;
5374         loff_t ioffset;
5375
5376         /*
5377          * We need to test this early because xfstests assumes that an
5378          * insert range of (0, 1) will return EOPNOTSUPP if the file
5379          * system does not support insert range.
5380          */
5381         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5382                 return -EOPNOTSUPP;
5383
5384         /* Insert range works only on fs cluster size aligned regions. */
5385         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5386                 return -EINVAL;
5387
5388         trace_ext4_insert_range(inode, offset, len);
5389
5390         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5391         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5392
5393         /* Call ext4_force_commit to flush all data in case of data=journal */
5394         if (ext4_should_journal_data(inode)) {
5395                 ret = ext4_force_commit(inode->i_sb);
5396                 if (ret)
5397                         return ret;
5398         }
5399
5400         inode_lock(inode);
5401         /* Currently just for extent based files */
5402         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5403                 ret = -EOPNOTSUPP;
5404                 goto out_mutex;
5405         }
5406
5407         /* Check whether the maximum file size would be exceeded */
5408         if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5409                 ret = -EFBIG;
5410                 goto out_mutex;
5411         }
5412
5413         /* Offset must be less than i_size */
5414         if (offset >= inode->i_size) {
5415                 ret = -EINVAL;
5416                 goto out_mutex;
5417         }
5418
5419         /* Wait for existing dio to complete */
5420         inode_dio_wait(inode);
5421
5422         /*
5423          * Prevent page faults from reinstantiating pages we have released from
5424          * page cache.
5425          */
5426         down_write(&EXT4_I(inode)->i_mmap_sem);
5427
5428         ret = ext4_break_layouts(inode);
5429         if (ret)
5430                 goto out_mmap;
5431
5432         /*
5433          * Need to round down to align start offset to page size boundary
5434          * for page size > block size.
5435          */
5436         ioffset = round_down(offset, PAGE_SIZE);
5437         /* Write out all dirty pages */
5438         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5439                         LLONG_MAX);
5440         if (ret)
5441                 goto out_mmap;
5442         truncate_pagecache(inode, ioffset);
5443
5444         credits = ext4_writepage_trans_blocks(inode);
5445         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5446         if (IS_ERR(handle)) {
5447                 ret = PTR_ERR(handle);
5448                 goto out_mmap;
5449         }
5450         ext4_fc_start_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE);
5451
5452         /* Expand file to avoid data loss if there is error while shifting */
5453         inode->i_size += len;
5454         EXT4_I(inode)->i_disksize += len;
5455         inode->i_mtime = inode->i_ctime = current_time(inode);
5456         ret = ext4_mark_inode_dirty(handle, inode);
5457         if (ret)
5458                 goto out_stop;
5459
5460         down_write(&EXT4_I(inode)->i_data_sem);
5461         ext4_discard_preallocations(inode, 0);
5462
5463         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5464         if (IS_ERR(path)) {
5465                 up_write(&EXT4_I(inode)->i_data_sem);
5466                 goto out_stop;
5467         }
5468
5469         depth = ext_depth(inode);
5470         extent = path[depth].p_ext;
5471         if (extent) {
5472                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5473                 ee_len = ext4_ext_get_actual_len(extent);
5474
5475                 /*
5476                  * If offset_lblk is not the starting block of extent, split
5477                  * the extent @offset_lblk
5478                  */
5479                 if ((offset_lblk > ee_start_lblk) &&
5480                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5481                         if (ext4_ext_is_unwritten(extent))
5482                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5483                                         EXT4_EXT_MARK_UNWRIT2;
5484                         ret = ext4_split_extent_at(handle, inode, &path,
5485                                         offset_lblk, split_flag,
5486                                         EXT4_EX_NOCACHE |
5487                                         EXT4_GET_BLOCKS_PRE_IO |
5488                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5489                 }
5490
5491                 ext4_ext_drop_refs(path);
5492                 kfree(path);
5493                 if (ret < 0) {
5494                         up_write(&EXT4_I(inode)->i_data_sem);
5495                         goto out_stop;
5496                 }
5497         } else {
5498                 ext4_ext_drop_refs(path);
5499                 kfree(path);
5500         }
5501
5502         ret = ext4_es_remove_extent(inode, offset_lblk,
5503                         EXT_MAX_BLOCKS - offset_lblk);
5504         if (ret) {
5505                 up_write(&EXT4_I(inode)->i_data_sem);
5506                 goto out_stop;
5507         }
5508
5509         /*
5510          * if offset_lblk lies in a hole which is at start of file, use
5511          * ee_start_lblk to shift extents
5512          */
5513         ret = ext4_ext_shift_extents(inode, handle,
5514                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5515                 len_lblk, SHIFT_RIGHT);
5516
5517         up_write(&EXT4_I(inode)->i_data_sem);
5518         if (IS_SYNC(inode))
5519                 ext4_handle_sync(handle);
5520         if (ret >= 0)
5521                 ext4_update_inode_fsync_trans(handle, inode, 1);
5522
5523 out_stop:
5524         ext4_journal_stop(handle);
5525         ext4_fc_stop_ineligible(sb);
5526 out_mmap:
5527         up_write(&EXT4_I(inode)->i_mmap_sem);
5528 out_mutex:
5529         inode_unlock(inode);
5530         return ret;
5531 }
5532
5533 /**
5534  * ext4_swap_extents() - Swap extents between two inodes
5535  * @handle: handle for this transaction
5536  * @inode1:     First inode
5537  * @inode2:     Second inode
5538  * @lblk1:      Start block for first inode
5539  * @lblk2:      Start block for second inode
5540  * @count:      Number of blocks to swap
5541  * @unwritten: Mark second inode's extents as unwritten after swap
5542  * @erp:        Pointer to save error value
5543  *
5544  * This helper routine does exactly what is promise "swap extents". All other
5545  * stuff such as page-cache locking consistency, bh mapping consistency or
5546  * extent's data copying must be performed by caller.
5547  * Locking:
5548  *              i_mutex is held for both inodes
5549  *              i_data_sem is locked for write for both inodes
5550  * Assumptions:
5551  *              All pages from requested range are locked for both inodes
5552  */
5553 int
5554 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5555                   struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5556                   ext4_lblk_t count, int unwritten, int *erp)
5557 {
5558         struct ext4_ext_path *path1 = NULL;
5559         struct ext4_ext_path *path2 = NULL;
5560         int replaced_count = 0;
5561
5562         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5563         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5564         BUG_ON(!inode_is_locked(inode1));
5565         BUG_ON(!inode_is_locked(inode2));
5566
5567         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5568         if (unlikely(*erp))
5569                 return 0;
5570         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5571         if (unlikely(*erp))
5572                 return 0;
5573
5574         while (count) {
5575                 struct ext4_extent *ex1, *ex2, tmp_ex;
5576                 ext4_lblk_t e1_blk, e2_blk;
5577                 int e1_len, e2_len, len;
5578                 int split = 0;
5579
5580                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5581                 if (IS_ERR(path1)) {
5582                         *erp = PTR_ERR(path1);
5583                         path1 = NULL;
5584                 finish:
5585                         count = 0;
5586                         goto repeat;
5587                 }
5588                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5589                 if (IS_ERR(path2)) {
5590                         *erp = PTR_ERR(path2);
5591                         path2 = NULL;
5592                         goto finish;
5593                 }
5594                 ex1 = path1[path1->p_depth].p_ext;
5595                 ex2 = path2[path2->p_depth].p_ext;
5596                 /* Do we have something to swap ? */
5597                 if (unlikely(!ex2 || !ex1))
5598                         goto finish;
5599
5600                 e1_blk = le32_to_cpu(ex1->ee_block);
5601                 e2_blk = le32_to_cpu(ex2->ee_block);
5602                 e1_len = ext4_ext_get_actual_len(ex1);
5603                 e2_len = ext4_ext_get_actual_len(ex2);
5604
5605                 /* Hole handling */
5606                 if (!in_range(lblk1, e1_blk, e1_len) ||
5607                     !in_range(lblk2, e2_blk, e2_len)) {
5608                         ext4_lblk_t next1, next2;
5609
5610                         /* if hole after extent, then go to next extent */
5611                         next1 = ext4_ext_next_allocated_block(path1);
5612                         next2 = ext4_ext_next_allocated_block(path2);
5613                         /* If hole before extent, then shift to that extent */
5614                         if (e1_blk > lblk1)
5615                                 next1 = e1_blk;
5616                         if (e2_blk > lblk2)
5617                                 next2 = e2_blk;
5618                         /* Do we have something to swap */
5619                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5620                                 goto finish;
5621                         /* Move to the rightest boundary */
5622                         len = next1 - lblk1;
5623                         if (len < next2 - lblk2)
5624                                 len = next2 - lblk2;
5625                         if (len > count)
5626                                 len = count;
5627                         lblk1 += len;
5628                         lblk2 += len;
5629                         count -= len;
5630                         goto repeat;
5631                 }
5632
5633                 /* Prepare left boundary */
5634                 if (e1_blk < lblk1) {
5635                         split = 1;
5636                         *erp = ext4_force_split_extent_at(handle, inode1,
5637                                                 &path1, lblk1, 0);
5638                         if (unlikely(*erp))
5639                                 goto finish;
5640                 }
5641                 if (e2_blk < lblk2) {
5642                         split = 1;
5643                         *erp = ext4_force_split_extent_at(handle, inode2,
5644                                                 &path2,  lblk2, 0);
5645                         if (unlikely(*erp))
5646                                 goto finish;
5647                 }
5648                 /* ext4_split_extent_at() may result in leaf extent split,
5649                  * path must to be revalidated. */
5650                 if (split)
5651                         goto repeat;
5652
5653                 /* Prepare right boundary */
5654                 len = count;
5655                 if (len > e1_blk + e1_len - lblk1)
5656                         len = e1_blk + e1_len - lblk1;
5657                 if (len > e2_blk + e2_len - lblk2)
5658                         len = e2_blk + e2_len - lblk2;
5659
5660                 if (len != e1_len) {
5661                         split = 1;
5662                         *erp = ext4_force_split_extent_at(handle, inode1,
5663                                                 &path1, lblk1 + len, 0);
5664                         if (unlikely(*erp))
5665                                 goto finish;
5666                 }
5667                 if (len != e2_len) {
5668                         split = 1;
5669                         *erp = ext4_force_split_extent_at(handle, inode2,
5670                                                 &path2, lblk2 + len, 0);
5671                         if (*erp)
5672                                 goto finish;
5673                 }
5674                 /* ext4_split_extent_at() may result in leaf extent split,
5675                  * path must to be revalidated. */
5676                 if (split)
5677                         goto repeat;
5678
5679                 BUG_ON(e2_len != e1_len);
5680                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5681                 if (unlikely(*erp))
5682                         goto finish;
5683                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5684                 if (unlikely(*erp))
5685                         goto finish;
5686
5687                 /* Both extents are fully inside boundaries. Swap it now */
5688                 tmp_ex = *ex1;
5689                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5690                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5691                 ex1->ee_len = cpu_to_le16(e2_len);
5692                 ex2->ee_len = cpu_to_le16(e1_len);
5693                 if (unwritten)
5694                         ext4_ext_mark_unwritten(ex2);
5695                 if (ext4_ext_is_unwritten(&tmp_ex))
5696                         ext4_ext_mark_unwritten(ex1);
5697
5698                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5699                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5700                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5701                                       path2->p_depth);
5702                 if (unlikely(*erp))
5703                         goto finish;
5704                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5705                                       path1->p_depth);
5706                 /*
5707                  * Looks scarry ah..? second inode already points to new blocks,
5708                  * and it was successfully dirtied. But luckily error may happen
5709                  * only due to journal error, so full transaction will be
5710                  * aborted anyway.
5711                  */
5712                 if (unlikely(*erp))
5713                         goto finish;
5714                 lblk1 += len;
5715                 lblk2 += len;
5716                 replaced_count += len;
5717                 count -= len;
5718
5719         repeat:
5720                 ext4_ext_drop_refs(path1);
5721                 kfree(path1);
5722                 ext4_ext_drop_refs(path2);
5723                 kfree(path2);
5724                 path1 = path2 = NULL;
5725         }
5726         return replaced_count;
5727 }
5728
5729 /*
5730  * ext4_clu_mapped - determine whether any block in a logical cluster has
5731  *                   been mapped to a physical cluster
5732  *
5733  * @inode - file containing the logical cluster
5734  * @lclu - logical cluster of interest
5735  *
5736  * Returns 1 if any block in the logical cluster is mapped, signifying
5737  * that a physical cluster has been allocated for it.  Otherwise,
5738  * returns 0.  Can also return negative error codes.  Derived from
5739  * ext4_ext_map_blocks().
5740  */
5741 int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5742 {
5743         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5744         struct ext4_ext_path *path;
5745         int depth, mapped = 0, err = 0;
5746         struct ext4_extent *extent;
5747         ext4_lblk_t first_lblk, first_lclu, last_lclu;
5748
5749         /* search for the extent closest to the first block in the cluster */
5750         path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5751         if (IS_ERR(path)) {
5752                 err = PTR_ERR(path);
5753                 path = NULL;
5754                 goto out;
5755         }
5756
5757         depth = ext_depth(inode);
5758
5759         /*
5760          * A consistent leaf must not be empty.  This situation is possible,
5761          * though, _during_ tree modification, and it's why an assert can't
5762          * be put in ext4_find_extent().
5763          */
5764         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5765                 EXT4_ERROR_INODE(inode,
5766                     "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5767                                  (unsigned long) EXT4_C2B(sbi, lclu),
5768                                  depth, path[depth].p_block);
5769                 err = -EFSCORRUPTED;
5770                 goto out;
5771         }
5772
5773         extent = path[depth].p_ext;
5774
5775         /* can't be mapped if the extent tree is empty */
5776         if (extent == NULL)
5777                 goto out;
5778
5779         first_lblk = le32_to_cpu(extent->ee_block);
5780         first_lclu = EXT4_B2C(sbi, first_lblk);
5781
5782         /*
5783          * Three possible outcomes at this point - found extent spanning
5784          * the target cluster, to the left of the target cluster, or to the
5785          * right of the target cluster.  The first two cases are handled here.
5786          * The last case indicates the target cluster is not mapped.
5787          */
5788         if (lclu >= first_lclu) {
5789                 last_lclu = EXT4_B2C(sbi, first_lblk +
5790                                      ext4_ext_get_actual_len(extent) - 1);
5791                 if (lclu <= last_lclu) {
5792                         mapped = 1;
5793                 } else {
5794                         first_lblk = ext4_ext_next_allocated_block(path);
5795                         first_lclu = EXT4_B2C(sbi, first_lblk);
5796                         if (lclu == first_lclu)
5797                                 mapped = 1;
5798                 }
5799         }
5800
5801 out:
5802         ext4_ext_drop_refs(path);
5803         kfree(path);
5804
5805         return err ? err : mapped;
5806 }
5807
5808 /*
5809  * Updates physical block address and unwritten status of extent
5810  * starting at lblk start and of len. If such an extent doesn't exist,
5811  * this function splits the extent tree appropriately to create an
5812  * extent like this.  This function is called in the fast commit
5813  * replay path.  Returns 0 on success and error on failure.
5814  */
5815 int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
5816                               int len, int unwritten, ext4_fsblk_t pblk)
5817 {
5818         struct ext4_ext_path *path = NULL, *ppath;
5819         struct ext4_extent *ex;
5820         int ret;
5821
5822         path = ext4_find_extent(inode, start, NULL, 0);
5823         if (!path)
5824                 return -EINVAL;
5825         ex = path[path->p_depth].p_ext;
5826         if (!ex) {
5827                 ret = -EFSCORRUPTED;
5828                 goto out;
5829         }
5830
5831         if (le32_to_cpu(ex->ee_block) != start ||
5832                 ext4_ext_get_actual_len(ex) != len) {
5833                 /* We need to split this extent to match our extent first */
5834                 ppath = path;
5835                 down_write(&EXT4_I(inode)->i_data_sem);
5836                 ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
5837                 up_write(&EXT4_I(inode)->i_data_sem);
5838                 if (ret)
5839                         goto out;
5840                 kfree(path);
5841                 path = ext4_find_extent(inode, start, NULL, 0);
5842                 if (IS_ERR(path))
5843                         return -1;
5844                 ppath = path;
5845                 ex = path[path->p_depth].p_ext;
5846                 WARN_ON(le32_to_cpu(ex->ee_block) != start);
5847                 if (ext4_ext_get_actual_len(ex) != len) {
5848                         down_write(&EXT4_I(inode)->i_data_sem);
5849                         ret = ext4_force_split_extent_at(NULL, inode, &ppath,
5850                                                          start + len, 1);
5851                         up_write(&EXT4_I(inode)->i_data_sem);
5852                         if (ret)
5853                                 goto out;
5854                         kfree(path);
5855                         path = ext4_find_extent(inode, start, NULL, 0);
5856                         if (IS_ERR(path))
5857                                 return -EINVAL;
5858                         ex = path[path->p_depth].p_ext;
5859                 }
5860         }
5861         if (unwritten)
5862                 ext4_ext_mark_unwritten(ex);
5863         else
5864                 ext4_ext_mark_initialized(ex);
5865         ext4_ext_store_pblock(ex, pblk);
5866         down_write(&EXT4_I(inode)->i_data_sem);
5867         ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5868         up_write(&EXT4_I(inode)->i_data_sem);
5869 out:
5870         ext4_ext_drop_refs(path);
5871         kfree(path);
5872         ext4_mark_inode_dirty(NULL, inode);
5873         return ret;
5874 }
5875
5876 /* Try to shrink the extent tree */
5877 void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
5878 {
5879         struct ext4_ext_path *path = NULL;
5880         struct ext4_extent *ex;
5881         ext4_lblk_t old_cur, cur = 0;
5882
5883         while (cur < end) {
5884                 path = ext4_find_extent(inode, cur, NULL, 0);
5885                 if (IS_ERR(path))
5886                         return;
5887                 ex = path[path->p_depth].p_ext;
5888                 if (!ex) {
5889                         ext4_ext_drop_refs(path);
5890                         kfree(path);
5891                         ext4_mark_inode_dirty(NULL, inode);
5892                         return;
5893                 }
5894                 old_cur = cur;
5895                 cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5896                 if (cur <= old_cur)
5897                         cur = old_cur + 1;
5898                 ext4_ext_try_to_merge(NULL, inode, path, ex);
5899                 down_write(&EXT4_I(inode)->i_data_sem);
5900                 ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5901                 up_write(&EXT4_I(inode)->i_data_sem);
5902                 ext4_mark_inode_dirty(NULL, inode);
5903                 ext4_ext_drop_refs(path);
5904                 kfree(path);
5905         }
5906 }
5907
5908 /* Check if *cur is a hole and if it is, skip it */
5909 static void skip_hole(struct inode *inode, ext4_lblk_t *cur)
5910 {
5911         int ret;
5912         struct ext4_map_blocks map;
5913
5914         map.m_lblk = *cur;
5915         map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
5916
5917         ret = ext4_map_blocks(NULL, inode, &map, 0);
5918         if (ret != 0)
5919                 return;
5920         *cur = *cur + map.m_len;
5921 }
5922
5923 /* Count number of blocks used by this inode and update i_blocks */
5924 int ext4_ext_replay_set_iblocks(struct inode *inode)
5925 {
5926         struct ext4_ext_path *path = NULL, *path2 = NULL;
5927         struct ext4_extent *ex;
5928         ext4_lblk_t cur = 0, end;
5929         int numblks = 0, i, ret = 0;
5930         ext4_fsblk_t cmp1, cmp2;
5931         struct ext4_map_blocks map;
5932
5933         /* Determin the size of the file first */
5934         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5935                                         EXT4_EX_NOCACHE);
5936         if (IS_ERR(path))
5937                 return PTR_ERR(path);
5938         ex = path[path->p_depth].p_ext;
5939         if (!ex) {
5940                 ext4_ext_drop_refs(path);
5941                 kfree(path);
5942                 goto out;
5943         }
5944         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5945         ext4_ext_drop_refs(path);
5946         kfree(path);
5947
5948         /* Count the number of data blocks */
5949         cur = 0;
5950         while (cur < end) {
5951                 map.m_lblk = cur;
5952                 map.m_len = end - cur;
5953                 ret = ext4_map_blocks(NULL, inode, &map, 0);
5954                 if (ret < 0)
5955                         break;
5956                 if (ret > 0)
5957                         numblks += ret;
5958                 cur = cur + map.m_len;
5959         }
5960
5961         /*
5962          * Count the number of extent tree blocks. We do it by looking up
5963          * two successive extents and determining the difference between
5964          * their paths. When path is different for 2 successive extents
5965          * we compare the blocks in the path at each level and increment
5966          * iblocks by total number of differences found.
5967          */
5968         cur = 0;
5969         skip_hole(inode, &cur);
5970         path = ext4_find_extent(inode, cur, NULL, 0);
5971         if (IS_ERR(path))
5972                 goto out;
5973         numblks += path->p_depth;
5974         ext4_ext_drop_refs(path);
5975         kfree(path);
5976         while (cur < end) {
5977                 path = ext4_find_extent(inode, cur, NULL, 0);
5978                 if (IS_ERR(path))
5979                         break;
5980                 ex = path[path->p_depth].p_ext;
5981                 if (!ex) {
5982                         ext4_ext_drop_refs(path);
5983                         kfree(path);
5984                         return 0;
5985                 }
5986                 cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
5987                                         ext4_ext_get_actual_len(ex));
5988                 skip_hole(inode, &cur);
5989
5990                 path2 = ext4_find_extent(inode, cur, NULL, 0);
5991                 if (IS_ERR(path2)) {
5992                         ext4_ext_drop_refs(path);
5993                         kfree(path);
5994                         break;
5995                 }
5996                 ex = path2[path2->p_depth].p_ext;
5997                 for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
5998                         cmp1 = cmp2 = 0;
5999                         if (i <= path->p_depth)
6000                                 cmp1 = path[i].p_bh ?
6001                                         path[i].p_bh->b_blocknr : 0;
6002                         if (i <= path2->p_depth)
6003                                 cmp2 = path2[i].p_bh ?
6004                                         path2[i].p_bh->b_blocknr : 0;
6005                         if (cmp1 != cmp2 && cmp2 != 0)
6006                                 numblks++;
6007                 }
6008                 ext4_ext_drop_refs(path);
6009                 ext4_ext_drop_refs(path2);
6010                 kfree(path);
6011                 kfree(path2);
6012         }
6013
6014 out:
6015         inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
6016         ext4_mark_inode_dirty(NULL, inode);
6017         return 0;
6018 }
6019
6020 int ext4_ext_clear_bb(struct inode *inode)
6021 {
6022         struct ext4_ext_path *path = NULL;
6023         struct ext4_extent *ex;
6024         ext4_lblk_t cur = 0, end;
6025         int j, ret = 0;
6026         struct ext4_map_blocks map;
6027
6028         /* Determin the size of the file first */
6029         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6030                                         EXT4_EX_NOCACHE);
6031         if (IS_ERR(path))
6032                 return PTR_ERR(path);
6033         ex = path[path->p_depth].p_ext;
6034         if (!ex) {
6035                 ext4_ext_drop_refs(path);
6036                 kfree(path);
6037                 return 0;
6038         }
6039         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6040         ext4_ext_drop_refs(path);
6041         kfree(path);
6042
6043         cur = 0;
6044         while (cur < end) {
6045                 map.m_lblk = cur;
6046                 map.m_len = end - cur;
6047                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6048                 if (ret < 0)
6049                         break;
6050                 if (ret > 0) {
6051                         path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
6052                         if (!IS_ERR_OR_NULL(path)) {
6053                                 for (j = 0; j < path->p_depth; j++) {
6054
6055                                         ext4_mb_mark_bb(inode->i_sb,
6056                                                         path[j].p_block, 1, 0);
6057                                 }
6058                                 ext4_ext_drop_refs(path);
6059                                 kfree(path);
6060                         }
6061                         ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
6062                 }
6063                 cur = cur + map.m_len;
6064         }
6065
6066         return 0;
6067 }