git.itanic.dy.fi Git - linux-stable/blob - 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/iomap.h>
  31 #include <linux/sched/mm.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_rwsem. 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         int err = 0;
 140
 141         if (path->p_bh) {
 142                 /* path points to block */
 143                 BUFFER_TRACE(path->p_bh, "get_write_access");
 144                 err = ext4_journal_get_write_access(handle, inode->i_sb,
 145                                                     path->p_bh, EXT4_JTR_NONE);
 146                 /*
 147                  * The extent buffer's verified bit will be set again in
 148                  * __ext4_ext_dirty(). We could leave an inconsistent
 149                  * buffer if the extents updating procudure break off du
 150                  * to some error happens, force to check it again.
 151                  */
 152                 if (!err)
 153                         clear_buffer_verified(path->p_bh);
 154         }
 155         /* path points to leaf/index in inode body */
 156         /* we use in-core data, no need to protect them */
 157         return err;
 158 }
 159
 160 /*
 161  * could return:
 162  *  - EROFS
 163  *  - ENOMEM
 164  *  - EIO
 165  */
 166 static int __ext4_ext_dirty(const char *where, unsigned int line,
 167                             handle_t *handle, struct inode *inode,
 168                             struct ext4_ext_path *path)
 169 {
 170         int err;
 171
 172         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 173         if (path->p_bh) {
 174                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 175                 /* path points to block */
 176                 err = __ext4_handle_dirty_metadata(where, line, handle,
 177                                                    inode, path->p_bh);
 178                 /* Extents updating done, re-set verified flag */
 179                 if (!err)
 180                         set_buffer_verified(path->p_bh);
 181         } else {
 182                 /* path points to leaf/index in inode body */
 183                 err = ext4_mark_inode_dirty(handle, inode);
 184         }
 185         return err;
 186 }
 187
 188 #define ext4_ext_dirty(handle, inode, path) \
 189                 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
 190
 191 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 192                               struct ext4_ext_path *path,
 193                               ext4_lblk_t block)
 194 {
 195         if (path) {
 196                 int depth = path->p_depth;
 197                 struct ext4_extent *ex;
 198
 199                 /*
 200                  * Try to predict block placement assuming that we are
 201                  * filling in a file which will eventually be
 202                  * non-sparse --- i.e., in the case of libbfd writing
 203                  * an ELF object sections out-of-order but in a way
 204                  * the eventually results in a contiguous object or
 205                  * executable file, or some database extending a table
 206                  * space file.  However, this is actually somewhat
 207                  * non-ideal if we are writing a sparse file such as
 208                  * qemu or KVM writing a raw image file that is going
 209                  * to stay fairly sparse, since it will end up
 210                  * fragmenting the file system's free space.  Maybe we
 211                  * should have some hueristics or some way to allow
 212                  * userspace to pass a hint to file system,
 213                  * especially if the latter case turns out to be
 214                  * common.
 215                  */
 216                 ex = path[depth].p_ext;
 217                 if (ex) {
 218                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 219                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 220
 221                         if (block > ext_block)
 222                                 return ext_pblk + (block - ext_block);
 223                         else
 224                                 return ext_pblk - (ext_block - block);
 225                 }
 226
 227                 /* it looks like index is empty;
 228                  * try to find starting block from index itself */
 229                 if (path[depth].p_bh)
 230                         return path[depth].p_bh->b_blocknr;
 231         }
 232
 233         /* OK. use inode's group */
 234         return ext4_inode_to_goal_block(inode);
 235 }
 236
 237 /*
 238  * Allocation for a meta data block
 239  */
 240 static ext4_fsblk_t
 241 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 242                         struct ext4_ext_path *path,
 243                         struct ext4_extent *ex, int *err, unsigned int flags)
 244 {
 245         ext4_fsblk_t goal, newblock;
 246
 247         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 248         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 249                                         NULL, err);
 250         return newblock;
 251 }
 252
 253 static inline int ext4_ext_space_block(struct inode *inode, int check)
 254 {
 255         int size;
 256
 257         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 258                         / sizeof(struct ext4_extent);
 259 #ifdef AGGRESSIVE_TEST
 260         if (!check && size > 6)
 261                 size = 6;
 262 #endif
 263         return size;
 264 }
 265
 266 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 267 {
 268         int size;
 269
 270         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 271                         / sizeof(struct ext4_extent_idx);
 272 #ifdef AGGRESSIVE_TEST
 273         if (!check && size > 5)
 274                 size = 5;
 275 #endif
 276         return size;
 277 }
 278
 279 static inline int ext4_ext_space_root(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);
 286 #ifdef AGGRESSIVE_TEST
 287         if (!check && size > 3)
 288                 size = 3;
 289 #endif
 290         return size;
 291 }
 292
 293 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 294 {
 295         int size;
 296
 297         size = sizeof(EXT4_I(inode)->i_data);
 298         size -= sizeof(struct ext4_extent_header);
 299         size /= sizeof(struct ext4_extent_idx);
 300 #ifdef AGGRESSIVE_TEST
 301         if (!check && size > 4)
 302                 size = 4;
 303 #endif
 304         return size;
 305 }
 306
 307 static inline int
 308 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 309                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 310                            int nofail)
 311 {
 312         struct ext4_ext_path *path = *ppath;
 313         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 314         int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO;
 315
 316         if (nofail)
 317                 flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL;
 318
 319         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 320                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 321                         flags);
 322 }
 323
 324 static int
 325 ext4_ext_max_entries(struct inode *inode, int depth)
 326 {
 327         int max;
 328
 329         if (depth == ext_depth(inode)) {
 330                 if (depth == 0)
 331                         max = ext4_ext_space_root(inode, 1);
 332                 else
 333                         max = ext4_ext_space_root_idx(inode, 1);
 334         } else {
 335                 if (depth == 0)
 336                         max = ext4_ext_space_block(inode, 1);
 337                 else
 338                         max = ext4_ext_space_block_idx(inode, 1);
 339         }
 340
 341         return max;
 342 }
 343
 344 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 345 {
 346         ext4_fsblk_t block = ext4_ext_pblock(ext);
 347         int len = ext4_ext_get_actual_len(ext);
 348         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 349
 350         /*
 351          * We allow neither:
 352          *  - zero length
 353          *  - overflow/wrap-around
 354          */
 355         if (lblock + len <= lblock)
 356                 return 0;
 357         return ext4_inode_block_valid(inode, block, len);
 358 }
 359
 360 static int ext4_valid_extent_idx(struct inode *inode,
 361                                 struct ext4_extent_idx *ext_idx)
 362 {
 363         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 364
 365         return ext4_inode_block_valid(inode, block, 1);
 366 }
 367
 368 static int ext4_valid_extent_entries(struct inode *inode,
 369                                      struct ext4_extent_header *eh,
 370                                      ext4_lblk_t lblk, ext4_fsblk_t *pblk,
 371                                      int depth)
 372 {
 373         unsigned short entries;
 374         ext4_lblk_t lblock = 0;
 375         ext4_lblk_t cur = 0;
 376
 377         if (eh->eh_entries == 0)
 378                 return 1;
 379
 380         entries = le16_to_cpu(eh->eh_entries);
 381
 382         if (depth == 0) {
 383                 /* leaf entries */
 384                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 385
 386                 /*
 387                  * The logical block in the first entry should equal to
 388                  * the number in the index block.
 389                  */
 390                 if (depth != ext_depth(inode) &&
 391                     lblk != le32_to_cpu(ext->ee_block))
 392                         return 0;
 393                 while (entries) {
 394                         if (!ext4_valid_extent(inode, ext))
 395                                 return 0;
 396
 397                         /* Check for overlapping extents */
 398                         lblock = le32_to_cpu(ext->ee_block);
 399                         if (lblock < cur) {
 400                                 *pblk = ext4_ext_pblock(ext);
 401                                 return 0;
 402                         }
 403                         cur = lblock + ext4_ext_get_actual_len(ext);
 404                         ext++;
 405                         entries--;
 406                 }
 407         } else {
 408                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 409
 410                 /*
 411                  * The logical block in the first entry should equal to
 412                  * the number in the parent index block.
 413                  */
 414                 if (depth != ext_depth(inode) &&
 415                     lblk != le32_to_cpu(ext_idx->ei_block))
 416                         return 0;
 417                 while (entries) {
 418                         if (!ext4_valid_extent_idx(inode, ext_idx))
 419                                 return 0;
 420
 421                         /* Check for overlapping index extents */
 422                         lblock = le32_to_cpu(ext_idx->ei_block);
 423                         if (lblock < cur) {
 424                                 *pblk = ext4_idx_pblock(ext_idx);
 425                                 return 0;
 426                         }
 427                         ext_idx++;
 428                         entries--;
 429                         cur = lblock + 1;
 430                 }
 431         }
 432         return 1;
 433 }
 434
 435 static int __ext4_ext_check(const char *function, unsigned int line,
 436                             struct inode *inode, struct ext4_extent_header *eh,
 437                             int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk)
 438 {
 439         const char *error_msg;
 440         int max = 0, err = -EFSCORRUPTED;
 441
 442         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 443                 error_msg = "invalid magic";
 444                 goto corrupted;
 445         }
 446         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 447                 error_msg = "unexpected eh_depth";
 448                 goto corrupted;
 449         }
 450         if (unlikely(eh->eh_max == 0)) {
 451                 error_msg = "invalid eh_max";
 452                 goto corrupted;
 453         }
 454         max = ext4_ext_max_entries(inode, depth);
 455         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 456                 error_msg = "too large eh_max";
 457                 goto corrupted;
 458         }
 459         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 460                 error_msg = "invalid eh_entries";
 461                 goto corrupted;
 462         }
 463         if (unlikely((eh->eh_entries == 0) && (depth > 0))) {
 464                 error_msg = "eh_entries is 0 but eh_depth is > 0";
 465                 goto corrupted;
 466         }
 467         if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) {
 468                 error_msg = "invalid extent entries";
 469                 goto corrupted;
 470         }
 471         if (unlikely(depth > 32)) {
 472                 error_msg = "too large eh_depth";
 473                 goto corrupted;
 474         }
 475         /* Verify checksum on non-root extent tree nodes */
 476         if (ext_depth(inode) != depth &&
 477             !ext4_extent_block_csum_verify(inode, eh)) {
 478                 error_msg = "extent tree corrupted";
 479                 err = -EFSBADCRC;
 480                 goto corrupted;
 481         }
 482         return 0;
 483
 484 corrupted:
 485         ext4_error_inode_err(inode, function, line, 0, -err,
 486                              "pblk %llu bad header/extent: %s - magic %x, "
 487                              "entries %u, max %u(%u), depth %u(%u)",
 488                              (unsigned long long) pblk, error_msg,
 489                              le16_to_cpu(eh->eh_magic),
 490                              le16_to_cpu(eh->eh_entries),
 491                              le16_to_cpu(eh->eh_max),
 492                              max, le16_to_cpu(eh->eh_depth), depth);
 493         return err;
 494 }
 495
 496 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 497         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)
 498
 499 int ext4_ext_check_inode(struct inode *inode)
 500 {
 501         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 502 }
 503
 504 static void ext4_cache_extents(struct inode *inode,
 505                                struct ext4_extent_header *eh)
 506 {
 507         struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 508         ext4_lblk_t prev = 0;
 509         int i;
 510
 511         for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 512                 unsigned int status = EXTENT_STATUS_WRITTEN;
 513                 ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 514                 int len = ext4_ext_get_actual_len(ex);
 515
 516                 if (prev && (prev != lblk))
 517                         ext4_es_cache_extent(inode, prev, lblk - prev, ~0,
 518                                              EXTENT_STATUS_HOLE);
 519
 520                 if (ext4_ext_is_unwritten(ex))
 521                         status = EXTENT_STATUS_UNWRITTEN;
 522                 ext4_es_cache_extent(inode, lblk, len,
 523                                      ext4_ext_pblock(ex), status);
 524                 prev = lblk + len;
 525         }
 526 }
 527
 528 static struct buffer_head *
 529 __read_extent_tree_block(const char *function, unsigned int line,
 530                          struct inode *inode, struct ext4_extent_idx *idx,
 531                          int depth, int flags)
 532 {
 533         struct buffer_head              *bh;
 534         int                             err;
 535         gfp_t                           gfp_flags = __GFP_MOVABLE | GFP_NOFS;
 536         ext4_fsblk_t                    pblk;
 537
 538         if (flags & EXT4_EX_NOFAIL)
 539                 gfp_flags |= __GFP_NOFAIL;
 540
 541         pblk = ext4_idx_pblock(idx);
 542         bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);
 543         if (unlikely(!bh))
 544                 return ERR_PTR(-ENOMEM);
 545
 546         if (!bh_uptodate_or_lock(bh)) {
 547                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 548                 err = ext4_read_bh(bh, 0, NULL);
 549                 if (err < 0)
 550                         goto errout;
 551         }
 552         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 553                 return bh;
 554         err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh),
 555                                depth, pblk, le32_to_cpu(idx->ei_block));
 556         if (err)
 557                 goto errout;
 558         set_buffer_verified(bh);
 559         /*
 560          * If this is a leaf block, cache all of its entries
 561          */
 562         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 563                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 564                 ext4_cache_extents(inode, eh);
 565         }
 566         return bh;
 567 errout:
 568         put_bh(bh);
 569         return ERR_PTR(err);
 570
 571 }
 572
 573 #define read_extent_tree_block(inode, idx, depth, flags)                \
 574         __read_extent_tree_block(__func__, __LINE__, (inode), (idx),    \
 575                                  (depth), (flags))
 576
 577 /*
 578  * This function is called to cache a file's extent information in the
 579  * extent status tree
 580  */
 581 int ext4_ext_precache(struct inode *inode)
 582 {
 583         struct ext4_inode_info *ei = EXT4_I(inode);
 584         struct ext4_ext_path *path = NULL;
 585         struct buffer_head *bh;
 586         int i = 0, depth, ret = 0;
 587
 588         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 589                 return 0;       /* not an extent-mapped inode */
 590
 591         down_read(&ei->i_data_sem);
 592         depth = ext_depth(inode);
 593
 594         /* Don't cache anything if there are no external extent blocks */
 595         if (!depth) {
 596                 up_read(&ei->i_data_sem);
 597                 return ret;
 598         }
 599
 600         path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
 601                        GFP_NOFS);
 602         if (path == NULL) {
 603                 up_read(&ei->i_data_sem);
 604                 return -ENOMEM;
 605         }
 606
 607         path[0].p_hdr = ext_inode_hdr(inode);
 608         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 609         if (ret)
 610                 goto out;
 611         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 612         while (i >= 0) {
 613                 /*
 614                  * If this is a leaf block or we've reached the end of
 615                  * the index block, go up
 616                  */
 617                 if ((i == depth) ||
 618                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 619                         brelse(path[i].p_bh);
 620                         path[i].p_bh = NULL;
 621                         i--;
 622                         continue;
 623                 }
 624                 bh = read_extent_tree_block(inode, path[i].p_idx++,
 625                                             depth - i - 1,
 626                                             EXT4_EX_FORCE_CACHE);
 627                 if (IS_ERR(bh)) {
 628                         ret = PTR_ERR(bh);
 629                         break;
 630                 }
 631                 i++;
 632                 path[i].p_bh = bh;
 633                 path[i].p_hdr = ext_block_hdr(bh);
 634                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 635         }
 636         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 637 out:
 638         up_read(&ei->i_data_sem);
 639         ext4_ext_drop_refs(path);
 640         kfree(path);
 641         return ret;
 642 }
 643
 644 #ifdef EXT_DEBUG
 645 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 646 {
 647         int k, l = path->p_depth;
 648
 649         ext_debug(inode, "path:");
 650         for (k = 0; k <= l; k++, path++) {
 651                 if (path->p_idx) {
 652                         ext_debug(inode, "  %d->%llu",
 653                                   le32_to_cpu(path->p_idx->ei_block),
 654                                   ext4_idx_pblock(path->p_idx));
 655                 } else if (path->p_ext) {
 656                         ext_debug(inode, "  %d:[%d]%d:%llu ",
 657                                   le32_to_cpu(path->p_ext->ee_block),
 658                                   ext4_ext_is_unwritten(path->p_ext),
 659                                   ext4_ext_get_actual_len(path->p_ext),
 660                                   ext4_ext_pblock(path->p_ext));
 661                 } else
 662                         ext_debug(inode, "  []");
 663         }
 664         ext_debug(inode, "\n");
 665 }
 666
 667 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 668 {
 669         int depth = ext_depth(inode);
 670         struct ext4_extent_header *eh;
 671         struct ext4_extent *ex;
 672         int i;
 673
 674         if (!path)
 675                 return;
 676
 677         eh = path[depth].p_hdr;
 678         ex = EXT_FIRST_EXTENT(eh);
 679
 680         ext_debug(inode, "Displaying leaf extents\n");
 681
 682         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 683                 ext_debug(inode, "%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 684                           ext4_ext_is_unwritten(ex),
 685                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 686         }
 687         ext_debug(inode, "\n");
 688 }
 689
 690 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 691                         ext4_fsblk_t newblock, int level)
 692 {
 693         int depth = ext_depth(inode);
 694         struct ext4_extent *ex;
 695
 696         if (depth != level) {
 697                 struct ext4_extent_idx *idx;
 698                 idx = path[level].p_idx;
 699                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 700                         ext_debug(inode, "%d: move %d:%llu in new index %llu\n",
 701                                   level, le32_to_cpu(idx->ei_block),
 702                                   ext4_idx_pblock(idx), newblock);
 703                         idx++;
 704                 }
 705
 706                 return;
 707         }
 708
 709         ex = path[depth].p_ext;
 710         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 711                 ext_debug(inode, "move %d:%llu:[%d]%d in new leaf %llu\n",
 712                                 le32_to_cpu(ex->ee_block),
 713                                 ext4_ext_pblock(ex),
 714                                 ext4_ext_is_unwritten(ex),
 715                                 ext4_ext_get_actual_len(ex),
 716                                 newblock);
 717                 ex++;
 718         }
 719 }
 720
 721 #else
 722 #define ext4_ext_show_path(inode, path)
 723 #define ext4_ext_show_leaf(inode, path)
 724 #define ext4_ext_show_move(inode, path, newblock, level)
 725 #endif
 726
 727 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 728 {
 729         int depth, i;
 730
 731         if (!path)
 732                 return;
 733         depth = path->p_depth;
 734         for (i = 0; i <= depth; i++, path++) {
 735                 brelse(path->p_bh);
 736                 path->p_bh = NULL;
 737         }
 738 }
 739
 740 /*
 741  * ext4_ext_binsearch_idx:
 742  * binary search for the closest index of the given block
 743  * the header must be checked before calling this
 744  */
 745 static void
 746 ext4_ext_binsearch_idx(struct inode *inode,
 747                         struct ext4_ext_path *path, ext4_lblk_t block)
 748 {
 749         struct ext4_extent_header *eh = path->p_hdr;
 750         struct ext4_extent_idx *r, *l, *m;
 751
 752
 753         ext_debug(inode, "binsearch for %u(idx):  ", block);
 754
 755         l = EXT_FIRST_INDEX(eh) + 1;
 756         r = EXT_LAST_INDEX(eh);
 757         while (l <= r) {
 758                 m = l + (r - l) / 2;
 759                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 760                           le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block),
 761                           r, le32_to_cpu(r->ei_block));
 762
 763                 if (block < le32_to_cpu(m->ei_block))
 764                         r = m - 1;
 765                 else
 766                         l = m + 1;
 767         }
 768
 769         path->p_idx = l - 1;
 770         ext_debug(inode, "  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 771                   ext4_idx_pblock(path->p_idx));
 772
 773 #ifdef CHECK_BINSEARCH
 774         {
 775                 struct ext4_extent_idx *chix, *ix;
 776                 int k;
 777
 778                 chix = ix = EXT_FIRST_INDEX(eh);
 779                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 780                         if (k != 0 && le32_to_cpu(ix->ei_block) <=
 781                             le32_to_cpu(ix[-1].ei_block)) {
 782                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 783                                        "first=0x%p\n", k,
 784                                        ix, EXT_FIRST_INDEX(eh));
 785                                 printk(KERN_DEBUG "%u <= %u\n",
 786                                        le32_to_cpu(ix->ei_block),
 787                                        le32_to_cpu(ix[-1].ei_block));
 788                         }
 789                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 790                                            <= le32_to_cpu(ix[-1].ei_block));
 791                         if (block < le32_to_cpu(ix->ei_block))
 792                                 break;
 793                         chix = ix;
 794                 }
 795                 BUG_ON(chix != path->p_idx);
 796         }
 797 #endif
 798
 799 }
 800
 801 /*
 802  * ext4_ext_binsearch:
 803  * binary search for closest extent of the given block
 804  * the header must be checked before calling this
 805  */
 806 static void
 807 ext4_ext_binsearch(struct inode *inode,
 808                 struct ext4_ext_path *path, ext4_lblk_t block)
 809 {
 810         struct ext4_extent_header *eh = path->p_hdr;
 811         struct ext4_extent *r, *l, *m;
 812
 813         if (eh->eh_entries == 0) {
 814                 /*
 815                  * this leaf is empty:
 816                  * we get such a leaf in split/add case
 817                  */
 818                 return;
 819         }
 820
 821         ext_debug(inode, "binsearch for %u:  ", block);
 822
 823         l = EXT_FIRST_EXTENT(eh) + 1;
 824         r = EXT_LAST_EXTENT(eh);
 825
 826         while (l <= r) {
 827                 m = l + (r - l) / 2;
 828                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 829                           le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block),
 830                           r, le32_to_cpu(r->ee_block));
 831
 832                 if (block < le32_to_cpu(m->ee_block))
 833                         r = m - 1;
 834                 else
 835                         l = m + 1;
 836         }
 837
 838         path->p_ext = l - 1;
 839         ext_debug(inode, "  -> %d:%llu:[%d]%d ",
 840                         le32_to_cpu(path->p_ext->ee_block),
 841                         ext4_ext_pblock(path->p_ext),
 842                         ext4_ext_is_unwritten(path->p_ext),
 843                         ext4_ext_get_actual_len(path->p_ext));
 844
 845 #ifdef CHECK_BINSEARCH
 846         {
 847                 struct ext4_extent *chex, *ex;
 848                 int k;
 849
 850                 chex = ex = EXT_FIRST_EXTENT(eh);
 851                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 852                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 853                                           <= le32_to_cpu(ex[-1].ee_block));
 854                         if (block < le32_to_cpu(ex->ee_block))
 855                                 break;
 856                         chex = ex;
 857                 }
 858                 BUG_ON(chex != path->p_ext);
 859         }
 860 #endif
 861
 862 }
 863
 864 void ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 865 {
 866         struct ext4_extent_header *eh;
 867
 868         eh = ext_inode_hdr(inode);
 869         eh->eh_depth = 0;
 870         eh->eh_entries = 0;
 871         eh->eh_magic = EXT4_EXT_MAGIC;
 872         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 873         eh->eh_generation = 0;
 874         ext4_mark_inode_dirty(handle, inode);
 875 }
 876
 877 struct ext4_ext_path *
 878 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 879                  struct ext4_ext_path **orig_path, int flags)
 880 {
 881         struct ext4_extent_header *eh;
 882         struct buffer_head *bh;
 883         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 884         short int depth, i, ppos = 0;
 885         int ret;
 886         gfp_t gfp_flags = GFP_NOFS;
 887
 888         if (flags & EXT4_EX_NOFAIL)
 889                 gfp_flags |= __GFP_NOFAIL;
 890
 891         eh = ext_inode_hdr(inode);
 892         depth = ext_depth(inode);
 893         if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
 894                 EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
 895                                  depth);
 896                 ret = -EFSCORRUPTED;
 897                 goto err;
 898         }
 899
 900         if (path) {
 901                 ext4_ext_drop_refs(path);
 902                 if (depth > path[0].p_maxdepth) {
 903                         kfree(path);
 904                         *orig_path = path = NULL;
 905                 }
 906         }
 907         if (!path) {
 908                 /* account possible depth increase */
 909                 path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
 910                                 gfp_flags);
 911                 if (unlikely(!path))
 912                         return ERR_PTR(-ENOMEM);
 913                 path[0].p_maxdepth = depth + 1;
 914         }
 915         path[0].p_hdr = eh;
 916         path[0].p_bh = NULL;
 917
 918         i = depth;
 919         if (!(flags & EXT4_EX_NOCACHE) && depth == 0)
 920                 ext4_cache_extents(inode, eh);
 921         /* walk through the tree */
 922         while (i) {
 923                 ext_debug(inode, "depth %d: num %d, max %d\n",
 924                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 925
 926                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 927                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 928                 path[ppos].p_depth = i;
 929                 path[ppos].p_ext = NULL;
 930
 931                 bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);
 932                 if (IS_ERR(bh)) {
 933                         ret = PTR_ERR(bh);
 934                         goto err;
 935                 }
 936
 937                 eh = ext_block_hdr(bh);
 938                 ppos++;
 939                 path[ppos].p_bh = bh;
 940                 path[ppos].p_hdr = eh;
 941         }
 942
 943         path[ppos].p_depth = i;
 944         path[ppos].p_ext = NULL;
 945         path[ppos].p_idx = NULL;
 946
 947         /* find extent */
 948         ext4_ext_binsearch(inode, path + ppos, block);
 949         /* if not an empty leaf */
 950         if (path[ppos].p_ext)
 951                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 952
 953         ext4_ext_show_path(inode, path);
 954
 955         return path;
 956
 957 err:
 958         ext4_ext_drop_refs(path);
 959         kfree(path);
 960         if (orig_path)
 961                 *orig_path = NULL;
 962         return ERR_PTR(ret);
 963 }
 964
 965 /*
 966  * ext4_ext_insert_index:
 967  * insert new index [@logical;@ptr] into the block at @curp;
 968  * check where to insert: before @curp or after @curp
 969  */
 970 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 971                                  struct ext4_ext_path *curp,
 972                                  int logical, ext4_fsblk_t ptr)
 973 {
 974         struct ext4_extent_idx *ix;
 975         int len, err;
 976
 977         err = ext4_ext_get_access(handle, inode, curp);
 978         if (err)
 979                 return err;
 980
 981         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 982                 EXT4_ERROR_INODE(inode,
 983                                  "logical %d == ei_block %d!",
 984                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 985                 return -EFSCORRUPTED;
 986         }
 987
 988         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 989                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 990                 EXT4_ERROR_INODE(inode,
 991                                  "eh_entries %d >= eh_max %d!",
 992                                  le16_to_cpu(curp->p_hdr->eh_entries),
 993                                  le16_to_cpu(curp->p_hdr->eh_max));
 994                 return -EFSCORRUPTED;
 995         }
 996
 997         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 998                 /* insert after */
 999                 ext_debug(inode, "insert new index %d after: %llu\n",
1000                           logical, ptr);
1001                 ix = curp->p_idx + 1;
1002         } else {
1003                 /* insert before */
1004                 ext_debug(inode, "insert new index %d before: %llu\n",
1005                           logical, ptr);
1006                 ix = curp->p_idx;
1007         }
1008
1009         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
1010         BUG_ON(len < 0);
1011         if (len > 0) {
1012                 ext_debug(inode, "insert new index %d: "
1013                                 "move %d indices from 0x%p to 0x%p\n",
1014                                 logical, len, ix, ix + 1);
1015                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
1016         }
1017
1018         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
1019                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1020                 return -EFSCORRUPTED;
1021         }
1022
1023         ix->ei_block = cpu_to_le32(logical);
1024         ext4_idx_store_pblock(ix, ptr);
1025         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1026
1027         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1028                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1029                 return -EFSCORRUPTED;
1030         }
1031
1032         err = ext4_ext_dirty(handle, inode, curp);
1033         ext4_std_error(inode->i_sb, err);
1034
1035         return err;
1036 }
1037
1038 /*
1039  * ext4_ext_split:
1040  * inserts new subtree into the path, using free index entry
1041  * at depth @at:
1042  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1043  * - makes decision where to split
1044  * - moves remaining extents and index entries (right to the split point)
1045  *   into the newly allocated blocks
1046  * - initializes subtree
1047  */
1048 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1049                           unsigned int flags,
1050                           struct ext4_ext_path *path,
1051                           struct ext4_extent *newext, int at)
1052 {
1053         struct buffer_head *bh = NULL;
1054         int depth = ext_depth(inode);
1055         struct ext4_extent_header *neh;
1056         struct ext4_extent_idx *fidx;
1057         int i = at, k, m, a;
1058         ext4_fsblk_t newblock, oldblock;
1059         __le32 border;
1060         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1061         gfp_t gfp_flags = GFP_NOFS;
1062         int err = 0;
1063         size_t ext_size = 0;
1064
1065         if (flags & EXT4_EX_NOFAIL)
1066                 gfp_flags |= __GFP_NOFAIL;
1067
1068         /* make decision: where to split? */
1069         /* FIXME: now decision is simplest: at current extent */
1070
1071         /* if current leaf will be split, then we should use
1072          * border from split point */
1073         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1074                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1075                 return -EFSCORRUPTED;
1076         }
1077         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1078                 border = path[depth].p_ext[1].ee_block;
1079                 ext_debug(inode, "leaf will be split."
1080                                 " next leaf starts at %d\n",
1081                                   le32_to_cpu(border));
1082         } else {
1083                 border = newext->ee_block;
1084                 ext_debug(inode, "leaf will be added."
1085                                 " next leaf starts at %d\n",
1086                                 le32_to_cpu(border));
1087         }
1088
1089         /*
1090          * If error occurs, then we break processing
1091          * and mark filesystem read-only. index won't
1092          * be inserted and tree will be in consistent
1093          * state. Next mount will repair buffers too.
1094          */
1095
1096         /*
1097          * Get array to track all allocated blocks.
1098          * We need this to handle errors and free blocks
1099          * upon them.
1100          */
1101         ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), gfp_flags);
1102         if (!ablocks)
1103                 return -ENOMEM;
1104
1105         /* allocate all needed blocks */
1106         ext_debug(inode, "allocate %d blocks for indexes/leaf\n", depth - at);
1107         for (a = 0; a < depth - at; a++) {
1108                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1109                                                    newext, &err, flags);
1110                 if (newblock == 0)
1111                         goto cleanup;
1112                 ablocks[a] = newblock;
1113         }
1114
1115         /* initialize new leaf */
1116         newblock = ablocks[--a];
1117         if (unlikely(newblock == 0)) {
1118                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1119                 err = -EFSCORRUPTED;
1120                 goto cleanup;
1121         }
1122         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1123         if (unlikely(!bh)) {
1124                 err = -ENOMEM;
1125                 goto cleanup;
1126         }
1127         lock_buffer(bh);
1128
1129         err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1130                                              EXT4_JTR_NONE);
1131         if (err)
1132                 goto cleanup;
1133
1134         neh = ext_block_hdr(bh);
1135         neh->eh_entries = 0;
1136         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1137         neh->eh_magic = EXT4_EXT_MAGIC;
1138         neh->eh_depth = 0;
1139         neh->eh_generation = 0;
1140
1141         /* move remainder of path[depth] to the new leaf */
1142         if (unlikely(path[depth].p_hdr->eh_entries !=
1143                      path[depth].p_hdr->eh_max)) {
1144                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1145                                  path[depth].p_hdr->eh_entries,
1146                                  path[depth].p_hdr->eh_max);
1147                 err = -EFSCORRUPTED;
1148                 goto cleanup;
1149         }
1150         /* start copy from next extent */
1151         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1152         ext4_ext_show_move(inode, path, newblock, depth);
1153         if (m) {
1154                 struct ext4_extent *ex;
1155                 ex = EXT_FIRST_EXTENT(neh);
1156                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1157                 le16_add_cpu(&neh->eh_entries, m);
1158         }
1159
1160         /* zero out unused area in the extent block */
1161         ext_size = sizeof(struct ext4_extent_header) +
1162                 sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries);
1163         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1164         ext4_extent_block_csum_set(inode, neh);
1165         set_buffer_uptodate(bh);
1166         unlock_buffer(bh);
1167
1168         err = ext4_handle_dirty_metadata(handle, inode, bh);
1169         if (err)
1170                 goto cleanup;
1171         brelse(bh);
1172         bh = NULL;
1173
1174         /* correct old leaf */
1175         if (m) {
1176                 err = ext4_ext_get_access(handle, inode, path + depth);
1177                 if (err)
1178                         goto cleanup;
1179                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1180                 err = ext4_ext_dirty(handle, inode, path + depth);
1181                 if (err)
1182                         goto cleanup;
1183
1184         }
1185
1186         /* create intermediate indexes */
1187         k = depth - at - 1;
1188         if (unlikely(k < 0)) {
1189                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1190                 err = -EFSCORRUPTED;
1191                 goto cleanup;
1192         }
1193         if (k)
1194                 ext_debug(inode, "create %d intermediate indices\n", k);
1195         /* insert new index into current index block */
1196         /* current depth stored in i var */
1197         i = depth - 1;
1198         while (k--) {
1199                 oldblock = newblock;
1200                 newblock = ablocks[--a];
1201                 bh = sb_getblk(inode->i_sb, newblock);
1202                 if (unlikely(!bh)) {
1203                         err = -ENOMEM;
1204                         goto cleanup;
1205                 }
1206                 lock_buffer(bh);
1207
1208                 err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1209                                                      EXT4_JTR_NONE);
1210                 if (err)
1211                         goto cleanup;
1212
1213                 neh = ext_block_hdr(bh);
1214                 neh->eh_entries = cpu_to_le16(1);
1215                 neh->eh_magic = EXT4_EXT_MAGIC;
1216                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1217                 neh->eh_depth = cpu_to_le16(depth - i);
1218                 neh->eh_generation = 0;
1219                 fidx = EXT_FIRST_INDEX(neh);
1220                 fidx->ei_block = border;
1221                 ext4_idx_store_pblock(fidx, oldblock);
1222
1223                 ext_debug(inode, "int.index at %d (block %llu): %u -> %llu\n",
1224                                 i, newblock, le32_to_cpu(border), oldblock);
1225
1226                 /* move remainder of path[i] to the new index block */
1227                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1228                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1229                         EXT4_ERROR_INODE(inode,
1230                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1231                                          le32_to_cpu(path[i].p_ext->ee_block));
1232                         err = -EFSCORRUPTED;
1233                         goto cleanup;
1234                 }
1235                 /* start copy indexes */
1236                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1237                 ext_debug(inode, "cur 0x%p, last 0x%p\n", path[i].p_idx,
1238                                 EXT_MAX_INDEX(path[i].p_hdr));
1239                 ext4_ext_show_move(inode, path, newblock, i);
1240                 if (m) {
1241                         memmove(++fidx, path[i].p_idx,
1242                                 sizeof(struct ext4_extent_idx) * m);
1243                         le16_add_cpu(&neh->eh_entries, m);
1244                 }
1245                 /* zero out unused area in the extent block */
1246                 ext_size = sizeof(struct ext4_extent_header) +
1247                    (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));
1248                 memset(bh->b_data + ext_size, 0,
1249                         inode->i_sb->s_blocksize - ext_size);
1250                 ext4_extent_block_csum_set(inode, neh);
1251                 set_buffer_uptodate(bh);
1252                 unlock_buffer(bh);
1253
1254                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1255                 if (err)
1256                         goto cleanup;
1257                 brelse(bh);
1258                 bh = NULL;
1259
1260                 /* correct old index */
1261                 if (m) {
1262                         err = ext4_ext_get_access(handle, inode, path + i);
1263                         if (err)
1264                                 goto cleanup;
1265                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1266                         err = ext4_ext_dirty(handle, inode, path + i);
1267                         if (err)
1268                                 goto cleanup;
1269                 }
1270
1271                 i--;
1272         }
1273
1274         /* insert new index */
1275         err = ext4_ext_insert_index(handle, inode, path + at,
1276                                     le32_to_cpu(border), newblock);
1277
1278 cleanup:
1279         if (bh) {
1280                 if (buffer_locked(bh))
1281                         unlock_buffer(bh);
1282                 brelse(bh);
1283         }
1284
1285         if (err) {
1286                 /* free all allocated blocks in error case */
1287                 for (i = 0; i < depth; i++) {
1288                         if (!ablocks[i])
1289                                 continue;
1290                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1291                                          EXT4_FREE_BLOCKS_METADATA);
1292                 }
1293         }
1294         kfree(ablocks);
1295
1296         return err;
1297 }
1298
1299 /*
1300  * ext4_ext_grow_indepth:
1301  * implements tree growing procedure:
1302  * - allocates new block
1303  * - moves top-level data (index block or leaf) into the new block
1304  * - initializes new top-level, creating index that points to the
1305  *   just created block
1306  */
1307 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1308                                  unsigned int flags)
1309 {
1310         struct ext4_extent_header *neh;
1311         struct buffer_head *bh;
1312         ext4_fsblk_t newblock, goal = 0;
1313         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1314         int err = 0;
1315         size_t ext_size = 0;
1316
1317         /* Try to prepend new index to old one */
1318         if (ext_depth(inode))
1319                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1320         if (goal > le32_to_cpu(es->s_first_data_block)) {
1321                 flags |= EXT4_MB_HINT_TRY_GOAL;
1322                 goal--;
1323         } else
1324                 goal = ext4_inode_to_goal_block(inode);
1325         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1326                                         NULL, &err);
1327         if (newblock == 0)
1328                 return err;
1329
1330         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1331         if (unlikely(!bh))
1332                 return -ENOMEM;
1333         lock_buffer(bh);
1334
1335         err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1336                                              EXT4_JTR_NONE);
1337         if (err) {
1338                 unlock_buffer(bh);
1339                 goto out;
1340         }
1341
1342         ext_size = sizeof(EXT4_I(inode)->i_data);
1343         /* move top-level index/leaf into new block */
1344         memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);
1345         /* zero out unused area in the extent block */
1346         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1347
1348         /* set size of new block */
1349         neh = ext_block_hdr(bh);
1350         /* old root could have indexes or leaves
1351          * so calculate e_max right way */
1352         if (ext_depth(inode))
1353                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1354         else
1355                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1356         neh->eh_magic = EXT4_EXT_MAGIC;
1357         ext4_extent_block_csum_set(inode, neh);
1358         set_buffer_uptodate(bh);
1359         set_buffer_verified(bh);
1360         unlock_buffer(bh);
1361
1362         err = ext4_handle_dirty_metadata(handle, inode, bh);
1363         if (err)
1364                 goto out;
1365
1366         /* Update top-level index: num,max,pointer */
1367         neh = ext_inode_hdr(inode);
1368         neh->eh_entries = cpu_to_le16(1);
1369         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1370         if (neh->eh_depth == 0) {
1371                 /* Root extent block becomes index block */
1372                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1373                 EXT_FIRST_INDEX(neh)->ei_block =
1374                         EXT_FIRST_EXTENT(neh)->ee_block;
1375         }
1376         ext_debug(inode, "new root: num %d(%d), lblock %d, ptr %llu\n",
1377                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1378                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1379                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1380
1381         le16_add_cpu(&neh->eh_depth, 1);
1382         err = ext4_mark_inode_dirty(handle, inode);
1383 out:
1384         brelse(bh);
1385
1386         return err;
1387 }
1388
1389 /*
1390  * ext4_ext_create_new_leaf:
1391  * finds empty index and adds new leaf.
1392  * if no free index is found, then it requests in-depth growing.
1393  */
1394 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1395                                     unsigned int mb_flags,
1396                                     unsigned int gb_flags,
1397                                     struct ext4_ext_path **ppath,
1398                                     struct ext4_extent *newext)
1399 {
1400         struct ext4_ext_path *path = *ppath;
1401         struct ext4_ext_path *curp;
1402         int depth, i, err = 0;
1403
1404 repeat:
1405         i = depth = ext_depth(inode);
1406
1407         /* walk up to the tree and look for free index entry */
1408         curp = path + depth;
1409         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1410                 i--;
1411                 curp--;
1412         }
1413
1414         /* we use already allocated block for index block,
1415          * so subsequent data blocks should be contiguous */
1416         if (EXT_HAS_FREE_INDEX(curp)) {
1417                 /* if we found index with free entry, then use that
1418                  * entry: create all needed subtree and add new leaf */
1419                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1420                 if (err)
1421                         goto out;
1422
1423                 /* refill path */
1424                 path = ext4_find_extent(inode,
1425                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1426                                     ppath, gb_flags);
1427                 if (IS_ERR(path))
1428                         err = PTR_ERR(path);
1429         } else {
1430                 /* tree is full, time to grow in depth */
1431                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1432                 if (err)
1433                         goto out;
1434
1435                 /* refill path */
1436                 path = ext4_find_extent(inode,
1437                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1438                                     ppath, gb_flags);
1439                 if (IS_ERR(path)) {
1440                         err = PTR_ERR(path);
1441                         goto out;
1442                 }
1443
1444                 /*
1445                  * only first (depth 0 -> 1) produces free space;
1446                  * in all other cases we have to split the grown tree
1447                  */
1448                 depth = ext_depth(inode);
1449                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1450                         /* now we need to split */
1451                         goto repeat;
1452                 }
1453         }
1454
1455 out:
1456         return err;
1457 }
1458
1459 /*
1460  * search the closest allocated block to the left for *logical
1461  * and returns it at @logical + it's physical address at @phys
1462  * if *logical is the smallest allocated block, the function
1463  * returns 0 at @phys
1464  * return value contains 0 (success) or error code
1465  */
1466 static int ext4_ext_search_left(struct inode *inode,
1467                                 struct ext4_ext_path *path,
1468                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1469 {
1470         struct ext4_extent_idx *ix;
1471         struct ext4_extent *ex;
1472         int depth, ee_len;
1473
1474         if (unlikely(path == NULL)) {
1475                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1476                 return -EFSCORRUPTED;
1477         }
1478         depth = path->p_depth;
1479         *phys = 0;
1480
1481         if (depth == 0 && path->p_ext == NULL)
1482                 return 0;
1483
1484         /* usually extent in the path covers blocks smaller
1485          * then *logical, but it can be that extent is the
1486          * first one in the file */
1487
1488         ex = path[depth].p_ext;
1489         ee_len = ext4_ext_get_actual_len(ex);
1490         if (*logical < le32_to_cpu(ex->ee_block)) {
1491                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1492                         EXT4_ERROR_INODE(inode,
1493                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1494                                          *logical, le32_to_cpu(ex->ee_block));
1495                         return -EFSCORRUPTED;
1496                 }
1497                 while (--depth >= 0) {
1498                         ix = path[depth].p_idx;
1499                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1500                                 EXT4_ERROR_INODE(inode,
1501                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1502                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1503                                   le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block),
1504                                   depth);
1505                                 return -EFSCORRUPTED;
1506                         }
1507                 }
1508                 return 0;
1509         }
1510
1511         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1512                 EXT4_ERROR_INODE(inode,
1513                                  "logical %d < ee_block %d + ee_len %d!",
1514                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1515                 return -EFSCORRUPTED;
1516         }
1517
1518         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1519         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1520         return 0;
1521 }
1522
1523 /*
1524  * Search the closest allocated block to the right for *logical
1525  * and returns it at @logical + it's physical address at @phys.
1526  * If not exists, return 0 and @phys is set to 0. We will return
1527  * 1 which means we found an allocated block and ret_ex is valid.
1528  * Or return a (< 0) error code.
1529  */
1530 static int ext4_ext_search_right(struct inode *inode,
1531                                  struct ext4_ext_path *path,
1532                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1533                                  struct ext4_extent *ret_ex)
1534 {
1535         struct buffer_head *bh = NULL;
1536         struct ext4_extent_header *eh;
1537         struct ext4_extent_idx *ix;
1538         struct ext4_extent *ex;
1539         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1540         int ee_len;
1541
1542         if (unlikely(path == NULL)) {
1543                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1544                 return -EFSCORRUPTED;
1545         }
1546         depth = path->p_depth;
1547         *phys = 0;
1548
1549         if (depth == 0 && path->p_ext == NULL)
1550                 return 0;
1551
1552         /* usually extent in the path covers blocks smaller
1553          * then *logical, but it can be that extent is the
1554          * first one in the file */
1555
1556         ex = path[depth].p_ext;
1557         ee_len = ext4_ext_get_actual_len(ex);
1558         if (*logical < le32_to_cpu(ex->ee_block)) {
1559                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1560                         EXT4_ERROR_INODE(inode,
1561                                          "first_extent(path[%d].p_hdr) != ex",
1562                                          depth);
1563                         return -EFSCORRUPTED;
1564                 }
1565                 while (--depth >= 0) {
1566                         ix = path[depth].p_idx;
1567                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1568                                 EXT4_ERROR_INODE(inode,
1569                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1570                                                  *logical);
1571                                 return -EFSCORRUPTED;
1572                         }
1573                 }
1574                 goto found_extent;
1575         }
1576
1577         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1578                 EXT4_ERROR_INODE(inode,
1579                                  "logical %d < ee_block %d + ee_len %d!",
1580                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1581                 return -EFSCORRUPTED;
1582         }
1583
1584         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1585                 /* next allocated block in this leaf */
1586                 ex++;
1587                 goto found_extent;
1588         }
1589
1590         /* go up and search for index to the right */
1591         while (--depth >= 0) {
1592                 ix = path[depth].p_idx;
1593                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1594                         goto got_index;
1595         }
1596
1597         /* we've gone up to the root and found no index to the right */
1598         return 0;
1599
1600 got_index:
1601         /* we've found index to the right, let's
1602          * follow it and find the closest allocated
1603          * block to the right */
1604         ix++;
1605         while (++depth < path->p_depth) {
1606                 /* subtract from p_depth to get proper eh_depth */
1607                 bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
1608                 if (IS_ERR(bh))
1609                         return PTR_ERR(bh);
1610                 eh = ext_block_hdr(bh);
1611                 ix = EXT_FIRST_INDEX(eh);
1612                 put_bh(bh);
1613         }
1614
1615         bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
1616         if (IS_ERR(bh))
1617                 return PTR_ERR(bh);
1618         eh = ext_block_hdr(bh);
1619         ex = EXT_FIRST_EXTENT(eh);
1620 found_extent:
1621         *logical = le32_to_cpu(ex->ee_block);
1622         *phys = ext4_ext_pblock(ex);
1623         if (ret_ex)
1624                 *ret_ex = *ex;
1625         if (bh)
1626                 put_bh(bh);
1627         return 1;
1628 }
1629
1630 /*
1631  * ext4_ext_next_allocated_block:
1632  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1633  * NOTE: it considers block number from index entry as
1634  * allocated block. Thus, index entries have to be consistent
1635  * with leaves.
1636  */
1637 ext4_lblk_t
1638 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1639 {
1640         int depth;
1641
1642         BUG_ON(path == NULL);
1643         depth = path->p_depth;
1644
1645         if (depth == 0 && path->p_ext == NULL)
1646                 return EXT_MAX_BLOCKS;
1647
1648         while (depth >= 0) {
1649                 struct ext4_ext_path *p = &path[depth];
1650
1651                 if (depth == path->p_depth) {
1652                         /* leaf */
1653                         if (p->p_ext && p->p_ext != EXT_LAST_EXTENT(p->p_hdr))
1654                                 return le32_to_cpu(p->p_ext[1].ee_block);
1655                 } else {
1656                         /* index */
1657                         if (p->p_idx != EXT_LAST_INDEX(p->p_hdr))
1658                                 return le32_to_cpu(p->p_idx[1].ei_block);
1659                 }
1660                 depth--;
1661         }
1662
1663         return EXT_MAX_BLOCKS;
1664 }
1665
1666 /*
1667  * ext4_ext_next_leaf_block:
1668  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1669  */
1670 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1671 {
1672         int depth;
1673
1674         BUG_ON(path == NULL);
1675         depth = path->p_depth;
1676
1677         /* zero-tree has no leaf blocks at all */
1678         if (depth == 0)
1679                 return EXT_MAX_BLOCKS;
1680
1681         /* go to index block */
1682         depth--;
1683
1684         while (depth >= 0) {
1685                 if (path[depth].p_idx !=
1686                                 EXT_LAST_INDEX(path[depth].p_hdr))
1687                         return (ext4_lblk_t)
1688                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1689                 depth--;
1690         }
1691
1692         return EXT_MAX_BLOCKS;
1693 }
1694
1695 /*
1696  * ext4_ext_correct_indexes:
1697  * if leaf gets modified and modified extent is first in the leaf,
1698  * then we have to correct all indexes above.
1699  * TODO: do we need to correct tree in all cases?
1700  */
1701 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1702                                 struct ext4_ext_path *path)
1703 {
1704         struct ext4_extent_header *eh;
1705         int depth = ext_depth(inode);
1706         struct ext4_extent *ex;
1707         __le32 border;
1708         int k, err = 0;
1709
1710         eh = path[depth].p_hdr;
1711         ex = path[depth].p_ext;
1712
1713         if (unlikely(ex == NULL || eh == NULL)) {
1714                 EXT4_ERROR_INODE(inode,
1715                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1716                 return -EFSCORRUPTED;
1717         }
1718
1719         if (depth == 0) {
1720                 /* there is no tree at all */
1721                 return 0;
1722         }
1723
1724         if (ex != EXT_FIRST_EXTENT(eh)) {
1725                 /* we correct tree if first leaf got modified only */
1726                 return 0;
1727         }
1728
1729         /*
1730          * TODO: we need correction if border is smaller than current one
1731          */
1732         k = depth - 1;
1733         border = path[depth].p_ext->ee_block;
1734         err = ext4_ext_get_access(handle, inode, path + k);
1735         if (err)
1736                 return err;
1737         path[k].p_idx->ei_block = border;
1738         err = ext4_ext_dirty(handle, inode, path + k);
1739         if (err)
1740                 return err;
1741
1742         while (k--) {
1743                 /* change all left-side indexes */
1744                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1745                         break;
1746                 err = ext4_ext_get_access(handle, inode, path + k);
1747                 if (err)
1748                         break;
1749                 path[k].p_idx->ei_block = border;
1750                 err = ext4_ext_dirty(handle, inode, path + k);
1751                 if (err)
1752                         break;
1753         }
1754
1755         return err;
1756 }
1757
1758 static int ext4_can_extents_be_merged(struct inode *inode,
1759                                       struct ext4_extent *ex1,
1760                                       struct ext4_extent *ex2)
1761 {
1762         unsigned short ext1_ee_len, ext2_ee_len;
1763
1764         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1765                 return 0;
1766
1767         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1768         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1769
1770         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1771                         le32_to_cpu(ex2->ee_block))
1772                 return 0;
1773
1774         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1775                 return 0;
1776
1777         if (ext4_ext_is_unwritten(ex1) &&
1778             ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)
1779                 return 0;
1780 #ifdef AGGRESSIVE_TEST
1781         if (ext1_ee_len >= 4)
1782                 return 0;
1783 #endif
1784
1785         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1786                 return 1;
1787         return 0;
1788 }
1789
1790 /*
1791  * This function tries to merge the "ex" extent to the next extent in the tree.
1792  * It always tries to merge towards right. If you want to merge towards
1793  * left, pass "ex - 1" as argument instead of "ex".
1794  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1795  * 1 if they got merged.
1796  */
1797 static int ext4_ext_try_to_merge_right(struct inode *inode,
1798                                  struct ext4_ext_path *path,
1799                                  struct ext4_extent *ex)
1800 {
1801         struct ext4_extent_header *eh;
1802         unsigned int depth, len;
1803         int merge_done = 0, unwritten;
1804
1805         depth = ext_depth(inode);
1806         BUG_ON(path[depth].p_hdr == NULL);
1807         eh = path[depth].p_hdr;
1808
1809         while (ex < EXT_LAST_EXTENT(eh)) {
1810                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1811                         break;
1812                 /* merge with next extent! */
1813                 unwritten = ext4_ext_is_unwritten(ex);
1814                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1815                                 + ext4_ext_get_actual_len(ex + 1));
1816                 if (unwritten)
1817                         ext4_ext_mark_unwritten(ex);
1818
1819                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1820                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1821                                 * sizeof(struct ext4_extent);
1822                         memmove(ex + 1, ex + 2, len);
1823                 }
1824                 le16_add_cpu(&eh->eh_entries, -1);
1825                 merge_done = 1;
1826                 WARN_ON(eh->eh_entries == 0);
1827                 if (!eh->eh_entries)
1828                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1829         }
1830
1831         return merge_done;
1832 }
1833
1834 /*
1835  * This function does a very simple check to see if we can collapse
1836  * an extent tree with a single extent tree leaf block into the inode.
1837  */
1838 static void ext4_ext_try_to_merge_up(handle_t *handle,
1839                                      struct inode *inode,
1840                                      struct ext4_ext_path *path)
1841 {
1842         size_t s;
1843         unsigned max_root = ext4_ext_space_root(inode, 0);
1844         ext4_fsblk_t blk;
1845
1846         if ((path[0].p_depth != 1) ||
1847             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1848             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1849                 return;
1850
1851         /*
1852          * We need to modify the block allocation bitmap and the block
1853          * group descriptor to release the extent tree block.  If we
1854          * can't get the journal credits, give up.
1855          */
1856         if (ext4_journal_extend(handle, 2,
1857                         ext4_free_metadata_revoke_credits(inode->i_sb, 1)))
1858                 return;
1859
1860         /*
1861          * Copy the extent data up to the inode
1862          */
1863         blk = ext4_idx_pblock(path[0].p_idx);
1864         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1865                 sizeof(struct ext4_extent_idx);
1866         s += sizeof(struct ext4_extent_header);
1867
1868         path[1].p_maxdepth = path[0].p_maxdepth;
1869         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1870         path[0].p_depth = 0;
1871         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1872                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1873         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1874
1875         brelse(path[1].p_bh);
1876         ext4_free_blocks(handle, inode, NULL, blk, 1,
1877                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1878 }
1879
1880 /*
1881  * This function tries to merge the @ex extent to neighbours in the tree, then
1882  * tries to collapse the extent tree into the inode.
1883  */
1884 static void ext4_ext_try_to_merge(handle_t *handle,
1885                                   struct inode *inode,
1886                                   struct ext4_ext_path *path,
1887                                   struct ext4_extent *ex)
1888 {
1889         struct ext4_extent_header *eh;
1890         unsigned int depth;
1891         int merge_done = 0;
1892
1893         depth = ext_depth(inode);
1894         BUG_ON(path[depth].p_hdr == NULL);
1895         eh = path[depth].p_hdr;
1896
1897         if (ex > EXT_FIRST_EXTENT(eh))
1898                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1899
1900         if (!merge_done)
1901                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1902
1903         ext4_ext_try_to_merge_up(handle, inode, path);
1904 }
1905
1906 /*
1907  * check if a portion of the "newext" extent overlaps with an
1908  * existing extent.
1909  *
1910  * If there is an overlap discovered, it updates the length of the newext
1911  * such that there will be no overlap, and then returns 1.
1912  * If there is no overlap found, it returns 0.
1913  */
1914 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1915                                            struct inode *inode,
1916                                            struct ext4_extent *newext,
1917                                            struct ext4_ext_path *path)
1918 {
1919         ext4_lblk_t b1, b2;
1920         unsigned int depth, len1;
1921         unsigned int ret = 0;
1922
1923         b1 = le32_to_cpu(newext->ee_block);
1924         len1 = ext4_ext_get_actual_len(newext);
1925         depth = ext_depth(inode);
1926         if (!path[depth].p_ext)
1927                 goto out;
1928         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1929
1930         /*
1931          * get the next allocated block if the extent in the path
1932          * is before the requested block(s)
1933          */
1934         if (b2 < b1) {
1935                 b2 = ext4_ext_next_allocated_block(path);
1936                 if (b2 == EXT_MAX_BLOCKS)
1937                         goto out;
1938                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1939         }
1940
1941         /* check for wrap through zero on extent logical start block*/
1942         if (b1 + len1 < b1) {
1943                 len1 = EXT_MAX_BLOCKS - b1;
1944                 newext->ee_len = cpu_to_le16(len1);
1945                 ret = 1;
1946         }
1947
1948         /* check for overlap */
1949         if (b1 + len1 > b2) {
1950                 newext->ee_len = cpu_to_le16(b2 - b1);
1951                 ret = 1;
1952         }
1953 out:
1954         return ret;
1955 }
1956
1957 /*
1958  * ext4_ext_insert_extent:
1959  * tries to merge requested extent into the existing extent or
1960  * inserts requested extent as new one into the tree,
1961  * creating new leaf in the no-space case.
1962  */
1963 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1964                                 struct ext4_ext_path **ppath,
1965                                 struct ext4_extent *newext, int gb_flags)
1966 {
1967         struct ext4_ext_path *path = *ppath;
1968         struct ext4_extent_header *eh;
1969         struct ext4_extent *ex, *fex;
1970         struct ext4_extent *nearex; /* nearest extent */
1971         struct ext4_ext_path *npath = NULL;
1972         int depth, len, err;
1973         ext4_lblk_t next;
1974         int mb_flags = 0, unwritten;
1975
1976         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1977                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1978         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1979                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1980                 return -EFSCORRUPTED;
1981         }
1982         depth = ext_depth(inode);
1983         ex = path[depth].p_ext;
1984         eh = path[depth].p_hdr;
1985         if (unlikely(path[depth].p_hdr == NULL)) {
1986                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1987                 return -EFSCORRUPTED;
1988         }
1989
1990         /* try to insert block into found extent and return */
1991         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1992
1993                 /*
1994                  * Try to see whether we should rather test the extent on
1995                  * right from ex, or from the left of ex. This is because
1996                  * ext4_find_extent() can return either extent on the
1997                  * left, or on the right from the searched position. This
1998                  * will make merging more effective.
1999                  */
2000                 if (ex < EXT_LAST_EXTENT(eh) &&
2001                     (le32_to_cpu(ex->ee_block) +
2002                     ext4_ext_get_actual_len(ex) <
2003                     le32_to_cpu(newext->ee_block))) {
2004                         ex += 1;
2005                         goto prepend;
2006                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
2007                            (le32_to_cpu(newext->ee_block) +
2008                            ext4_ext_get_actual_len(newext) <
2009                            le32_to_cpu(ex->ee_block)))
2010                         ex -= 1;
2011
2012                 /* Try to append newex to the ex */
2013                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
2014                         ext_debug(inode, "append [%d]%d block to %u:[%d]%d"
2015                                   "(from %llu)\n",
2016                                   ext4_ext_is_unwritten(newext),
2017                                   ext4_ext_get_actual_len(newext),
2018                                   le32_to_cpu(ex->ee_block),
2019                                   ext4_ext_is_unwritten(ex),
2020                                   ext4_ext_get_actual_len(ex),
2021                                   ext4_ext_pblock(ex));
2022                         err = ext4_ext_get_access(handle, inode,
2023                                                   path + depth);
2024                         if (err)
2025                                 return err;
2026                         unwritten = ext4_ext_is_unwritten(ex);
2027                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2028                                         + ext4_ext_get_actual_len(newext));
2029                         if (unwritten)
2030                                 ext4_ext_mark_unwritten(ex);
2031                         nearex = ex;
2032                         goto merge;
2033                 }
2034
2035 prepend:
2036                 /* Try to prepend newex to the ex */
2037                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2038                         ext_debug(inode, "prepend %u[%d]%d block to %u:[%d]%d"
2039                                   "(from %llu)\n",
2040                                   le32_to_cpu(newext->ee_block),
2041                                   ext4_ext_is_unwritten(newext),
2042                                   ext4_ext_get_actual_len(newext),
2043                                   le32_to_cpu(ex->ee_block),
2044                                   ext4_ext_is_unwritten(ex),
2045                                   ext4_ext_get_actual_len(ex),
2046                                   ext4_ext_pblock(ex));
2047                         err = ext4_ext_get_access(handle, inode,
2048                                                   path + depth);
2049                         if (err)
2050                                 return err;
2051
2052                         unwritten = ext4_ext_is_unwritten(ex);
2053                         ex->ee_block = newext->ee_block;
2054                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2055                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2056                                         + ext4_ext_get_actual_len(newext));
2057                         if (unwritten)
2058                                 ext4_ext_mark_unwritten(ex);
2059                         nearex = ex;
2060                         goto merge;
2061                 }
2062         }
2063
2064         depth = ext_depth(inode);
2065         eh = path[depth].p_hdr;
2066         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2067                 goto has_space;
2068
2069         /* probably next leaf has space for us? */
2070         fex = EXT_LAST_EXTENT(eh);
2071         next = EXT_MAX_BLOCKS;
2072         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2073                 next = ext4_ext_next_leaf_block(path);
2074         if (next != EXT_MAX_BLOCKS) {
2075                 ext_debug(inode, "next leaf block - %u\n", next);
2076                 BUG_ON(npath != NULL);
2077                 npath = ext4_find_extent(inode, next, NULL, gb_flags);
2078                 if (IS_ERR(npath))
2079                         return PTR_ERR(npath);
2080                 BUG_ON(npath->p_depth != path->p_depth);
2081                 eh = npath[depth].p_hdr;
2082                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2083                         ext_debug(inode, "next leaf isn't full(%d)\n",
2084                                   le16_to_cpu(eh->eh_entries));
2085                         path = npath;
2086                         goto has_space;
2087                 }
2088                 ext_debug(inode, "next leaf has no free space(%d,%d)\n",
2089                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2090         }
2091
2092         /*
2093          * There is no free space in the found leaf.
2094          * We're gonna add a new leaf in the tree.
2095          */
2096         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2097                 mb_flags |= EXT4_MB_USE_RESERVED;
2098         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2099                                        ppath, newext);
2100         if (err)
2101                 goto cleanup;
2102         depth = ext_depth(inode);
2103         eh = path[depth].p_hdr;
2104
2105 has_space:
2106         nearex = path[depth].p_ext;
2107
2108         err = ext4_ext_get_access(handle, inode, path + depth);
2109         if (err)
2110                 goto cleanup;
2111
2112         if (!nearex) {
2113                 /* there is no extent in this leaf, create first one */
2114                 ext_debug(inode, "first extent in the leaf: %u:%llu:[%d]%d\n",
2115                                 le32_to_cpu(newext->ee_block),
2116                                 ext4_ext_pblock(newext),
2117                                 ext4_ext_is_unwritten(newext),
2118                                 ext4_ext_get_actual_len(newext));
2119                 nearex = EXT_FIRST_EXTENT(eh);
2120         } else {
2121                 if (le32_to_cpu(newext->ee_block)
2122                            > le32_to_cpu(nearex->ee_block)) {
2123                         /* Insert after */
2124                         ext_debug(inode, "insert %u:%llu:[%d]%d before: "
2125                                         "nearest %p\n",
2126                                         le32_to_cpu(newext->ee_block),
2127                                         ext4_ext_pblock(newext),
2128                                         ext4_ext_is_unwritten(newext),
2129                                         ext4_ext_get_actual_len(newext),
2130                                         nearex);
2131                         nearex++;
2132                 } else {
2133                         /* Insert before */
2134                         BUG_ON(newext->ee_block == nearex->ee_block);
2135                         ext_debug(inode, "insert %u:%llu:[%d]%d after: "
2136                                         "nearest %p\n",
2137                                         le32_to_cpu(newext->ee_block),
2138                                         ext4_ext_pblock(newext),
2139                                         ext4_ext_is_unwritten(newext),
2140                                         ext4_ext_get_actual_len(newext),
2141                                         nearex);
2142                 }
2143                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2144                 if (len > 0) {
2145                         ext_debug(inode, "insert %u:%llu:[%d]%d: "
2146                                         "move %d extents from 0x%p to 0x%p\n",
2147                                         le32_to_cpu(newext->ee_block),
2148                                         ext4_ext_pblock(newext),
2149                                         ext4_ext_is_unwritten(newext),
2150                                         ext4_ext_get_actual_len(newext),
2151                                         len, nearex, nearex + 1);
2152                         memmove(nearex + 1, nearex,
2153                                 len * sizeof(struct ext4_extent));
2154                 }
2155         }
2156
2157         le16_add_cpu(&eh->eh_entries, 1);
2158         path[depth].p_ext = nearex;
2159         nearex->ee_block = newext->ee_block;
2160         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2161         nearex->ee_len = newext->ee_len;
2162
2163 merge:
2164         /* try to merge extents */
2165         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2166                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2167
2168
2169         /* time to correct all indexes above */
2170         err = ext4_ext_correct_indexes(handle, inode, path);
2171         if (err)
2172                 goto cleanup;
2173
2174         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2175
2176 cleanup:
2177         ext4_ext_drop_refs(npath);
2178         kfree(npath);
2179         return err;
2180 }
2181
2182 static int ext4_fill_es_cache_info(struct inode *inode,
2183                                    ext4_lblk_t block, ext4_lblk_t num,
2184                                    struct fiemap_extent_info *fieinfo)
2185 {
2186         ext4_lblk_t next, end = block + num - 1;
2187         struct extent_status es;
2188         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2189         unsigned int flags;
2190         int err;
2191
2192         while (block <= end) {
2193                 next = 0;
2194                 flags = 0;
2195                 if (!ext4_es_lookup_extent(inode, block, &next, &es))
2196                         break;
2197                 if (ext4_es_is_unwritten(&es))
2198                         flags |= FIEMAP_EXTENT_UNWRITTEN;
2199                 if (ext4_es_is_delayed(&es))
2200                         flags |= (FIEMAP_EXTENT_DELALLOC |
2201                                   FIEMAP_EXTENT_UNKNOWN);
2202                 if (ext4_es_is_hole(&es))
2203                         flags |= EXT4_FIEMAP_EXTENT_HOLE;
2204                 if (next == 0)
2205                         flags |= FIEMAP_EXTENT_LAST;
2206                 if (flags & (FIEMAP_EXTENT_DELALLOC|
2207                              EXT4_FIEMAP_EXTENT_HOLE))
2208                         es.es_pblk = 0;
2209                 else
2210                         es.es_pblk = ext4_es_pblock(&es);
2211                 err = fiemap_fill_next_extent(fieinfo,
2212                                 (__u64)es.es_lblk << blksize_bits,
2213                                 (__u64)es.es_pblk << blksize_bits,
2214                                 (__u64)es.es_len << blksize_bits,
2215                                 flags);
2216                 if (next == 0)
2217                         break;
2218                 block = next;
2219                 if (err < 0)
2220                         return err;
2221                 if (err == 1)
2222                         return 0;
2223         }
2224         return 0;
2225 }
2226
2227
2228 /*
2229  * ext4_ext_determine_hole - determine hole around given block
2230  * @inode:      inode we lookup in
2231  * @path:       path in extent tree to @lblk
2232  * @lblk:       pointer to logical block around which we want to determine hole
2233  *
2234  * Determine hole length (and start if easily possible) around given logical
2235  * block. We don't try too hard to find the beginning of the hole but @path
2236  * actually points to extent before @lblk, we provide it.
2237  *
2238  * The function returns the length of a hole starting at @lblk. We update @lblk
2239  * to the beginning of the hole if we managed to find it.
2240  */
2241 static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2242                                            struct ext4_ext_path *path,
2243                                            ext4_lblk_t *lblk)
2244 {
2245         int depth = ext_depth(inode);
2246         struct ext4_extent *ex;
2247         ext4_lblk_t len;
2248
2249         ex = path[depth].p_ext;
2250         if (ex == NULL) {
2251                 /* there is no extent yet, so gap is [0;-] */
2252                 *lblk = 0;
2253                 len = EXT_MAX_BLOCKS;
2254         } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2255                 len = le32_to_cpu(ex->ee_block) - *lblk;
2256         } else if (*lblk >= le32_to_cpu(ex->ee_block)
2257                         + ext4_ext_get_actual_len(ex)) {
2258                 ext4_lblk_t next;
2259
2260                 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2261                 next = ext4_ext_next_allocated_block(path);
2262                 BUG_ON(next == *lblk);
2263                 len = next - *lblk;
2264         } else {
2265                 BUG();
2266         }
2267         return len;
2268 }
2269
2270 /*
2271  * ext4_ext_put_gap_in_cache:
2272  * calculate boundaries of the gap that the requested block fits into
2273  * and cache this gap
2274  */
2275 static void
2276 ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2277                           ext4_lblk_t hole_len)
2278 {
2279         struct extent_status es;
2280
2281         ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
2282                                   hole_start + hole_len - 1, &es);
2283         if (es.es_len) {
2284                 /* There's delayed extent containing lblock? */
2285                 if (es.es_lblk <= hole_start)
2286                         return;
2287                 hole_len = min(es.es_lblk - hole_start, hole_len);
2288         }
2289         ext_debug(inode, " -> %u:%u\n", hole_start, hole_len);
2290         ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2291                               EXTENT_STATUS_HOLE);
2292 }
2293
2294 /*
2295  * ext4_ext_rm_idx:
2296  * removes index from the index block.
2297  */
2298 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2299                         struct ext4_ext_path *path, int depth)
2300 {
2301         int err;
2302         ext4_fsblk_t leaf;
2303
2304         /* free index block */
2305         depth--;
2306         path = path + depth;
2307         leaf = ext4_idx_pblock(path->p_idx);
2308         if (unlikely(path->p_hdr->eh_entries == 0)) {
2309                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2310                 return -EFSCORRUPTED;
2311         }
2312         err = ext4_ext_get_access(handle, inode, path);
2313         if (err)
2314                 return err;
2315
2316         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2317                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2318                 len *= sizeof(struct ext4_extent_idx);
2319                 memmove(path->p_idx, path->p_idx + 1, len);
2320         }
2321
2322         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2323         err = ext4_ext_dirty(handle, inode, path);
2324         if (err)
2325                 return err;
2326         ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
2327         trace_ext4_ext_rm_idx(inode, leaf);
2328
2329         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2330                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2331
2332         while (--depth >= 0) {
2333                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2334                         break;
2335                 path--;
2336                 err = ext4_ext_get_access(handle, inode, path);
2337                 if (err)
2338                         break;
2339                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2340                 err = ext4_ext_dirty(handle, inode, path);
2341                 if (err)
2342                         break;
2343         }
2344         return err;
2345 }
2346
2347 /*
2348  * ext4_ext_calc_credits_for_single_extent:
2349  * This routine returns max. credits that needed to insert an extent
2350  * to the extent tree.
2351  * When pass the actual path, the caller should calculate credits
2352  * under i_data_sem.
2353  */
2354 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2355                                                 struct ext4_ext_path *path)
2356 {
2357         if (path) {
2358                 int depth = ext_depth(inode);
2359                 int ret = 0;
2360
2361                 /* probably there is space in leaf? */
2362                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2363                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2364
2365                         /*
2366                          *  There are some space in the leaf tree, no
2367                          *  need to account for leaf block credit
2368                          *
2369                          *  bitmaps and block group descriptor blocks
2370                          *  and other metadata blocks still need to be
2371                          *  accounted.
2372                          */
2373                         /* 1 bitmap, 1 block group descriptor */
2374                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2375                         return ret;
2376                 }
2377         }
2378
2379         return ext4_chunk_trans_blocks(inode, nrblocks);
2380 }
2381
2382 /*
2383  * How many index/leaf blocks need to change/allocate to add @extents extents?
2384  *
2385  * If we add a single extent, then in the worse case, each tree level
2386  * index/leaf need to be changed in case of the tree split.
2387  *
2388  * If more extents are inserted, they could cause the whole tree split more
2389  * than once, but this is really rare.
2390  */
2391 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2392 {
2393         int index;
2394         int depth;
2395
2396         /* If we are converting the inline data, only one is needed here. */
2397         if (ext4_has_inline_data(inode))
2398                 return 1;
2399
2400         depth = ext_depth(inode);
2401
2402         if (extents <= 1)
2403                 index = depth * 2;
2404         else
2405                 index = depth * 3;
2406
2407         return index;
2408 }
2409
2410 static inline int get_default_free_blocks_flags(struct inode *inode)
2411 {
2412         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2413             ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2414                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2415         else if (ext4_should_journal_data(inode))
2416                 return EXT4_FREE_BLOCKS_FORGET;
2417         return 0;
2418 }
2419
2420 /*
2421  * ext4_rereserve_cluster - increment the reserved cluster count when
2422  *                          freeing a cluster with a pending reservation
2423  *
2424  * @inode - file containing the cluster
2425  * @lblk - logical block in cluster to be reserved
2426  *
2427  * Increments the reserved cluster count and adjusts quota in a bigalloc
2428  * file system when freeing a partial cluster containing at least one
2429  * delayed and unwritten block.  A partial cluster meeting that
2430  * requirement will have a pending reservation.  If so, the
2431  * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2432  * defer reserved and allocated space accounting to a subsequent call
2433  * to this function.
2434  */
2435 static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2436 {
2437         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2438         struct ext4_inode_info *ei = EXT4_I(inode);
2439
2440         dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2441
2442         spin_lock(&ei->i_block_reservation_lock);
2443         ei->i_reserved_data_blocks++;
2444         percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2445         spin_unlock(&ei->i_block_reservation_lock);
2446
2447         percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2448         ext4_remove_pending(inode, lblk);
2449 }
2450
2451 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2452                               struct ext4_extent *ex,
2453                               struct partial_cluster *partial,
2454                               ext4_lblk_t from, ext4_lblk_t to)
2455 {
2456         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2457         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2458         ext4_fsblk_t last_pblk, pblk;
2459         ext4_lblk_t num;
2460         int flags;
2461
2462         /* only extent tail removal is allowed */
2463         if (from < le32_to_cpu(ex->ee_block) ||
2464             to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2465                 ext4_error(sbi->s_sb,
2466                            "strange request: removal(2) %u-%u from %u:%u",
2467                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2468                 return 0;
2469         }
2470
2471 #ifdef EXTENTS_STATS
2472         spin_lock(&sbi->s_ext_stats_lock);
2473         sbi->s_ext_blocks += ee_len;
2474         sbi->s_ext_extents++;
2475         if (ee_len < sbi->s_ext_min)
2476                 sbi->s_ext_min = ee_len;
2477         if (ee_len > sbi->s_ext_max)
2478                 sbi->s_ext_max = ee_len;
2479         if (ext_depth(inode) > sbi->s_depth_max)
2480                 sbi->s_depth_max = ext_depth(inode);
2481         spin_unlock(&sbi->s_ext_stats_lock);
2482 #endif
2483
2484         trace_ext4_remove_blocks(inode, ex, from, to, partial);
2485
2486         /*
2487          * if we have a partial cluster, and it's different from the
2488          * cluster of the last block in the extent, we free it
2489          */
2490         last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2491
2492         if (partial->state != initial &&
2493             partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2494                 if (partial->state == tofree) {
2495                         flags = get_default_free_blocks_flags(inode);
2496                         if (ext4_is_pending(inode, partial->lblk))
2497                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2498                         ext4_free_blocks(handle, inode, NULL,
2499                                          EXT4_C2B(sbi, partial->pclu),
2500                                          sbi->s_cluster_ratio, flags);
2501                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2502                                 ext4_rereserve_cluster(inode, partial->lblk);
2503                 }
2504                 partial->state = initial;
2505         }
2506
2507         num = le32_to_cpu(ex->ee_block) + ee_len - from;
2508         pblk = ext4_ext_pblock(ex) + ee_len - num;
2509
2510         /*
2511          * We free the partial cluster at the end of the extent (if any),
2512          * unless the cluster is used by another extent (partial_cluster
2513          * state is nofree).  If a partial cluster exists here, it must be
2514          * shared with the last block in the extent.
2515          */
2516         flags = get_default_free_blocks_flags(inode);
2517
2518         /* partial, left end cluster aligned, right end unaligned */
2519         if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2520             (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2521             (partial->state != nofree)) {
2522                 if (ext4_is_pending(inode, to))
2523                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2524                 ext4_free_blocks(handle, inode, NULL,
2525                                  EXT4_PBLK_CMASK(sbi, last_pblk),
2526                                  sbi->s_cluster_ratio, flags);
2527                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2528                         ext4_rereserve_cluster(inode, to);
2529                 partial->state = initial;
2530                 flags = get_default_free_blocks_flags(inode);
2531         }
2532
2533         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2534
2535         /*
2536          * For bigalloc file systems, we never free a partial cluster
2537          * at the beginning of the extent.  Instead, we check to see if we
2538          * need to free it on a subsequent call to ext4_remove_blocks,
2539          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2540          */
2541         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2542         ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2543
2544         /* reset the partial cluster if we've freed past it */
2545         if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2546                 partial->state = initial;
2547
2548         /*
2549          * If we've freed the entire extent but the beginning is not left
2550          * cluster aligned and is not marked as ineligible for freeing we
2551          * record the partial cluster at the beginning of the extent.  It
2552          * wasn't freed by the preceding ext4_free_blocks() call, and we
2553          * need to look farther to the left to determine if it's to be freed
2554          * (not shared with another extent). Else, reset the partial
2555          * cluster - we're either  done freeing or the beginning of the
2556          * extent is left cluster aligned.
2557          */
2558         if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2559                 if (partial->state == initial) {
2560                         partial->pclu = EXT4_B2C(sbi, pblk);
2561                         partial->lblk = from;
2562                         partial->state = tofree;
2563                 }
2564         } else {
2565                 partial->state = initial;
2566         }
2567
2568         return 0;
2569 }
2570
2571 /*
2572  * ext4_ext_rm_leaf() Removes the extents associated with the
2573  * blocks appearing between "start" and "end".  Both "start"
2574  * and "end" must appear in the same extent or EIO is returned.
2575  *
2576  * @handle: The journal handle
2577  * @inode:  The files inode
2578  * @path:   The path to the leaf
2579  * @partial_cluster: The cluster which we'll have to free if all extents
2580  *                   has been released from it.  However, if this value is
2581  *                   negative, it's a cluster just to the right of the
2582  *                   punched region and it must not be freed.
2583  * @start:  The first block to remove
2584  * @end:   The last block to remove
2585  */
2586 static int
2587 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2588                  struct ext4_ext_path *path,
2589                  struct partial_cluster *partial,
2590                  ext4_lblk_t start, ext4_lblk_t end)
2591 {
2592         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2593         int err = 0, correct_index = 0;
2594         int depth = ext_depth(inode), credits, revoke_credits;
2595         struct ext4_extent_header *eh;
2596         ext4_lblk_t a, b;
2597         unsigned num;
2598         ext4_lblk_t ex_ee_block;
2599         unsigned short ex_ee_len;
2600         unsigned unwritten = 0;
2601         struct ext4_extent *ex;
2602         ext4_fsblk_t pblk;
2603
2604         /* the header must be checked already in ext4_ext_remove_space() */
2605         ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
2606         if (!path[depth].p_hdr)
2607                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2608         eh = path[depth].p_hdr;
2609         if (unlikely(path[depth].p_hdr == NULL)) {
2610                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2611                 return -EFSCORRUPTED;
2612         }
2613         /* find where to start removing */
2614         ex = path[depth].p_ext;
2615         if (!ex)
2616                 ex = EXT_LAST_EXTENT(eh);
2617
2618         ex_ee_block = le32_to_cpu(ex->ee_block);
2619         ex_ee_len = ext4_ext_get_actual_len(ex);
2620
2621         trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2622
2623         while (ex >= EXT_FIRST_EXTENT(eh) &&
2624                         ex_ee_block + ex_ee_len > start) {
2625
2626                 if (ext4_ext_is_unwritten(ex))
2627                         unwritten = 1;
2628                 else
2629                         unwritten = 0;
2630
2631                 ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
2632                           unwritten, ex_ee_len);
2633                 path[depth].p_ext = ex;
2634
2635                 a = ex_ee_block > start ? ex_ee_block : start;
2636                 b = ex_ee_block+ex_ee_len - 1 < end ?
2637                         ex_ee_block+ex_ee_len - 1 : end;
2638
2639                 ext_debug(inode, "  border %u:%u\n", a, b);
2640
2641                 /* If this extent is beyond the end of the hole, skip it */
2642                 if (end < ex_ee_block) {
2643                         /*
2644                          * We're going to skip this extent and move to another,
2645                          * so note that its first cluster is in use to avoid
2646                          * freeing it when removing blocks.  Eventually, the
2647                          * right edge of the truncated/punched region will
2648                          * be just to the left.
2649                          */
2650                         if (sbi->s_cluster_ratio > 1) {
2651                                 pblk = ext4_ext_pblock(ex);
2652                                 partial->pclu = EXT4_B2C(sbi, pblk);
2653                                 partial->state = nofree;
2654                         }
2655                         ex--;
2656                         ex_ee_block = le32_to_cpu(ex->ee_block);
2657                         ex_ee_len = ext4_ext_get_actual_len(ex);
2658                         continue;
2659                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2660                         EXT4_ERROR_INODE(inode,
2661                                          "can not handle truncate %u:%u "
2662                                          "on extent %u:%u",
2663                                          start, end, ex_ee_block,
2664                                          ex_ee_block + ex_ee_len - 1);
2665                         err = -EFSCORRUPTED;
2666                         goto out;
2667                 } else if (a != ex_ee_block) {
2668                         /* remove tail of the extent */
2669                         num = a - ex_ee_block;
2670                 } else {
2671                         /* remove whole extent: excellent! */
2672                         num = 0;
2673                 }
2674                 /*
2675                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2676                  * descriptor) for each block group; assume two block
2677                  * groups plus ex_ee_len/blocks_per_block_group for
2678                  * the worst case
2679                  */
2680                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2681                 if (ex == EXT_FIRST_EXTENT(eh)) {
2682                         correct_index = 1;
2683                         credits += (ext_depth(inode)) + 1;
2684                 }
2685                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2686                 /*
2687                  * We may end up freeing some index blocks and data from the
2688                  * punched range. Note that partial clusters are accounted for
2689                  * by ext4_free_data_revoke_credits().
2690                  */
2691                 revoke_credits =
2692                         ext4_free_metadata_revoke_credits(inode->i_sb,
2693                                                           ext_depth(inode)) +
2694                         ext4_free_data_revoke_credits(inode, b - a + 1);
2695
2696                 err = ext4_datasem_ensure_credits(handle, inode, credits,
2697                                                   credits, revoke_credits);
2698                 if (err) {
2699                         if (err > 0)
2700                                 err = -EAGAIN;
2701                         goto out;
2702                 }
2703
2704                 err = ext4_ext_get_access(handle, inode, path + depth);
2705                 if (err)
2706                         goto out;
2707
2708                 err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2709                 if (err)
2710                         goto out;
2711
2712                 if (num == 0)
2713                         /* this extent is removed; mark slot entirely unused */
2714                         ext4_ext_store_pblock(ex, 0);
2715
2716                 ex->ee_len = cpu_to_le16(num);
2717                 /*
2718                  * Do not mark unwritten if all the blocks in the
2719                  * extent have been removed.
2720                  */
2721                 if (unwritten && num)
2722                         ext4_ext_mark_unwritten(ex);
2723                 /*
2724                  * If the extent was completely released,
2725                  * we need to remove it from the leaf
2726                  */
2727                 if (num == 0) {
2728                         if (end != EXT_MAX_BLOCKS - 1) {
2729                                 /*
2730                                  * For hole punching, we need to scoot all the
2731                                  * extents up when an extent is removed so that
2732                                  * we dont have blank extents in the middle
2733                                  */
2734                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2735                                         sizeof(struct ext4_extent));
2736
2737                                 /* Now get rid of the one at the end */
2738                                 memset(EXT_LAST_EXTENT(eh), 0,
2739                                         sizeof(struct ext4_extent));
2740                         }
2741                         le16_add_cpu(&eh->eh_entries, -1);
2742                 }
2743
2744                 err = ext4_ext_dirty(handle, inode, path + depth);
2745                 if (err)
2746                         goto out;
2747
2748                 ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
2749                                 ext4_ext_pblock(ex));
2750                 ex--;
2751                 ex_ee_block = le32_to_cpu(ex->ee_block);
2752                 ex_ee_len = ext4_ext_get_actual_len(ex);
2753         }
2754
2755         if (correct_index && eh->eh_entries)
2756                 err = ext4_ext_correct_indexes(handle, inode, path);
2757
2758         /*
2759          * If there's a partial cluster and at least one extent remains in
2760          * the leaf, free the partial cluster if it isn't shared with the
2761          * current extent.  If it is shared with the current extent
2762          * we reset the partial cluster because we've reached the start of the
2763          * truncated/punched region and we're done removing blocks.
2764          */
2765         if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2766                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2767                 if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2768                         int flags = get_default_free_blocks_flags(inode);
2769
2770                         if (ext4_is_pending(inode, partial->lblk))
2771                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2772                         ext4_free_blocks(handle, inode, NULL,
2773                                          EXT4_C2B(sbi, partial->pclu),
2774                                          sbi->s_cluster_ratio, flags);
2775                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2776                                 ext4_rereserve_cluster(inode, partial->lblk);
2777                 }
2778                 partial->state = initial;
2779         }
2780
2781         /* if this leaf is free, then we should
2782          * remove it from index block above */
2783         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2784                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2785
2786 out:
2787         return err;
2788 }
2789
2790 /*
2791  * ext4_ext_more_to_rm:
2792  * returns 1 if current index has to be freed (even partial)
2793  */
2794 static int
2795 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2796 {
2797         BUG_ON(path->p_idx == NULL);
2798
2799         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2800                 return 0;
2801
2802         /*
2803          * if truncate on deeper level happened, it wasn't partial,
2804          * so we have to consider current index for truncation
2805          */
2806         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2807                 return 0;
2808         return 1;
2809 }
2810
2811 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2812                           ext4_lblk_t end)
2813 {
2814         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2815         int depth = ext_depth(inode);
2816         struct ext4_ext_path *path = NULL;
2817         struct partial_cluster partial;
2818         handle_t *handle;
2819         int i = 0, err = 0;
2820
2821         partial.pclu = 0;
2822         partial.lblk = 0;
2823         partial.state = initial;
2824
2825         ext_debug(inode, "truncate since %u to %u\n", start, end);
2826
2827         /* probably first extent we're gonna free will be last in block */
2828         handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2829                         depth + 1,
2830                         ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2831         if (IS_ERR(handle))
2832                 return PTR_ERR(handle);
2833
2834 again:
2835         trace_ext4_ext_remove_space(inode, start, end, depth);
2836
2837         /*
2838          * Check if we are removing extents inside the extent tree. If that
2839          * is the case, we are going to punch a hole inside the extent tree
2840          * so we have to check whether we need to split the extent covering
2841          * the last block to remove so we can easily remove the part of it
2842          * in ext4_ext_rm_leaf().
2843          */
2844         if (end < EXT_MAX_BLOCKS - 1) {
2845                 struct ext4_extent *ex;
2846                 ext4_lblk_t ee_block, ex_end, lblk;
2847                 ext4_fsblk_t pblk;
2848
2849                 /* find extent for or closest extent to this block */
2850                 path = ext4_find_extent(inode, end, NULL,
2851                                         EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
2852                 if (IS_ERR(path)) {
2853                         ext4_journal_stop(handle);
2854                         return PTR_ERR(path);
2855                 }
2856                 depth = ext_depth(inode);
2857                 /* Leaf not may not exist only if inode has no blocks at all */
2858                 ex = path[depth].p_ext;
2859                 if (!ex) {
2860                         if (depth) {
2861                                 EXT4_ERROR_INODE(inode,
2862                                                  "path[%d].p_hdr == NULL",
2863                                                  depth);
2864                                 err = -EFSCORRUPTED;
2865                         }
2866                         goto out;
2867                 }
2868
2869                 ee_block = le32_to_cpu(ex->ee_block);
2870                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2871
2872                 /*
2873                  * See if the last block is inside the extent, if so split
2874                  * the extent at 'end' block so we can easily remove the
2875                  * tail of the first part of the split extent in
2876                  * ext4_ext_rm_leaf().
2877                  */
2878                 if (end >= ee_block && end < ex_end) {
2879
2880                         /*
2881                          * If we're going to split the extent, note that
2882                          * the cluster containing the block after 'end' is
2883                          * in use to avoid freeing it when removing blocks.
2884                          */
2885                         if (sbi->s_cluster_ratio > 1) {
2886                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
2887                                 partial.pclu = EXT4_B2C(sbi, pblk);
2888                                 partial.state = nofree;
2889                         }
2890
2891                         /*
2892                          * Split the extent in two so that 'end' is the last
2893                          * block in the first new extent. Also we should not
2894                          * fail removing space due to ENOSPC so try to use
2895                          * reserved block if that happens.
2896                          */
2897                         err = ext4_force_split_extent_at(handle, inode, &path,
2898                                                          end + 1, 1);
2899                         if (err < 0)
2900                                 goto out;
2901
2902                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
2903                            partial.state == initial) {
2904                         /*
2905                          * If we're punching, there's an extent to the right.
2906                          * If the partial cluster hasn't been set, set it to
2907                          * that extent's first cluster and its state to nofree
2908                          * so it won't be freed should it contain blocks to be
2909                          * removed. If it's already set (tofree/nofree), we're
2910                          * retrying and keep the original partial cluster info
2911                          * so a cluster marked tofree as a result of earlier
2912                          * extent removal is not lost.
2913                          */
2914                         lblk = ex_end + 1;
2915                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2916                                                     NULL);
2917                         if (err < 0)
2918                                 goto out;
2919                         if (pblk) {
2920                                 partial.pclu = EXT4_B2C(sbi, pblk);
2921                                 partial.state = nofree;
2922                         }
2923                 }
2924         }
2925         /*
2926          * We start scanning from right side, freeing all the blocks
2927          * after i_size and walking into the tree depth-wise.
2928          */
2929         depth = ext_depth(inode);
2930         if (path) {
2931                 int k = i = depth;
2932                 while (--k > 0)
2933                         path[k].p_block =
2934                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2935         } else {
2936                 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
2937                                GFP_NOFS | __GFP_NOFAIL);
2938                 if (path == NULL) {
2939                         ext4_journal_stop(handle);
2940                         return -ENOMEM;
2941                 }
2942                 path[0].p_maxdepth = path[0].p_depth = depth;
2943                 path[0].p_hdr = ext_inode_hdr(inode);
2944                 i = 0;
2945
2946                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2947                         err = -EFSCORRUPTED;
2948                         goto out;
2949                 }
2950         }
2951         err = 0;
2952
2953         while (i >= 0 && err == 0) {
2954                 if (i == depth) {
2955                         /* this is leaf block */
2956                         err = ext4_ext_rm_leaf(handle, inode, path,
2957                                                &partial, start, end);
2958                         /* root level has p_bh == NULL, brelse() eats this */
2959                         brelse(path[i].p_bh);
2960                         path[i].p_bh = NULL;
2961                         i--;
2962                         continue;
2963                 }
2964
2965                 /* this is index block */
2966                 if (!path[i].p_hdr) {
2967                         ext_debug(inode, "initialize header\n");
2968                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2969                 }
2970
2971                 if (!path[i].p_idx) {
2972                         /* this level hasn't been touched yet */
2973                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2974                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2975                         ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
2976                                   path[i].p_hdr,
2977                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2978                 } else {
2979                         /* we were already here, see at next index */
2980                         path[i].p_idx--;
2981                 }
2982
2983                 ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
2984                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2985                                 path[i].p_idx);
2986                 if (ext4_ext_more_to_rm(path + i)) {
2987                         struct buffer_head *bh;
2988                         /* go to the next level */
2989                         ext_debug(inode, "move to level %d (block %llu)\n",
2990                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2991                         memset(path + i + 1, 0, sizeof(*path));
2992                         bh = read_extent_tree_block(inode, path[i].p_idx,
2993                                                     depth - i - 1,
2994                                                     EXT4_EX_NOCACHE);
2995                         if (IS_ERR(bh)) {
2996                                 /* should we reset i_size? */
2997                                 err = PTR_ERR(bh);
2998                                 break;
2999                         }
3000                         /* Yield here to deal with large extent trees.
3001                          * Should be a no-op if we did IO above. */
3002                         cond_resched();
3003                         if (WARN_ON(i + 1 > depth)) {
3004                                 err = -EFSCORRUPTED;
3005                                 break;
3006                         }
3007                         path[i + 1].p_bh = bh;
3008
3009                         /* save actual number of indexes since this
3010                          * number is changed at the next iteration */
3011                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3012                         i++;
3013                 } else {
3014                         /* we finished processing this index, go up */
3015                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3016                                 /* index is empty, remove it;
3017                                  * handle must be already prepared by the
3018                                  * truncatei_leaf() */
3019                                 err = ext4_ext_rm_idx(handle, inode, path, i);
3020                         }
3021                         /* root level has p_bh == NULL, brelse() eats this */
3022                         brelse(path[i].p_bh);
3023                         path[i].p_bh = NULL;
3024                         i--;
3025                         ext_debug(inode, "return to level %d\n", i);
3026                 }
3027         }
3028
3029         trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3030                                          path->p_hdr->eh_entries);
3031
3032         /*
3033          * if there's a partial cluster and we have removed the first extent
3034          * in the file, then we also free the partial cluster, if any
3035          */
3036         if (partial.state == tofree && err == 0) {
3037                 int flags = get_default_free_blocks_flags(inode);
3038
3039                 if (ext4_is_pending(inode, partial.lblk))
3040                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3041                 ext4_free_blocks(handle, inode, NULL,
3042                                  EXT4_C2B(sbi, partial.pclu),
3043                                  sbi->s_cluster_ratio, flags);
3044                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3045                         ext4_rereserve_cluster(inode, partial.lblk);
3046                 partial.state = initial;
3047         }
3048
3049         /* TODO: flexible tree reduction should be here */
3050         if (path->p_hdr->eh_entries == 0) {
3051                 /*
3052                  * truncate to zero freed all the tree,
3053                  * so we need to correct eh_depth
3054                  */
3055                 err = ext4_ext_get_access(handle, inode, path);
3056                 if (err == 0) {
3057                         ext_inode_hdr(inode)->eh_depth = 0;
3058                         ext_inode_hdr(inode)->eh_max =
3059                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3060                         err = ext4_ext_dirty(handle, inode, path);
3061                 }
3062         }
3063 out:
3064         ext4_ext_drop_refs(path);
3065         kfree(path);
3066         path = NULL;
3067         if (err == -EAGAIN)
3068                 goto again;
3069         ext4_journal_stop(handle);
3070
3071         return err;
3072 }
3073
3074 /*
3075  * called at mount time
3076  */
3077 void ext4_ext_init(struct super_block *sb)
3078 {
3079         /*
3080          * possible initialization would be here
3081          */
3082
3083         if (ext4_has_feature_extents(sb)) {
3084 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3085                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3086 #ifdef AGGRESSIVE_TEST
3087                        ", aggressive tests"
3088 #endif
3089 #ifdef CHECK_BINSEARCH
3090                        ", check binsearch"
3091 #endif
3092 #ifdef EXTENTS_STATS
3093                        ", stats"
3094 #endif
3095                        "\n");
3096 #endif
3097 #ifdef EXTENTS_STATS
3098                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3099                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3100                 EXT4_SB(sb)->s_ext_max = 0;
3101 #endif
3102         }
3103 }
3104
3105 /*
3106  * called at umount time
3107  */
3108 void ext4_ext_release(struct super_block *sb)
3109 {
3110         if (!ext4_has_feature_extents(sb))
3111                 return;
3112
3113 #ifdef EXTENTS_STATS
3114         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3115                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3116                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3117                         sbi->s_ext_blocks, sbi->s_ext_extents,
3118                         sbi->s_ext_blocks / sbi->s_ext_extents);
3119                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3120                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3121         }
3122 #endif
3123 }
3124
3125 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3126 {
3127         ext4_lblk_t  ee_block;
3128         ext4_fsblk_t ee_pblock;
3129         unsigned int ee_len;
3130
3131         ee_block  = le32_to_cpu(ex->ee_block);
3132         ee_len    = ext4_ext_get_actual_len(ex);
3133         ee_pblock = ext4_ext_pblock(ex);
3134
3135         if (ee_len == 0)
3136                 return 0;
3137
3138         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3139                                      EXTENT_STATUS_WRITTEN);
3140 }
3141
3142 /* FIXME!! we need to try to merge to left or right after zero-out  */
3143 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3144 {
3145         ext4_fsblk_t ee_pblock;
3146         unsigned int ee_len;
3147
3148         ee_len    = ext4_ext_get_actual_len(ex);
3149         ee_pblock = ext4_ext_pblock(ex);
3150         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3151                                   ee_len);
3152 }
3153
3154 /*
3155  * ext4_split_extent_at() splits an extent at given block.
3156  *
3157  * @handle: the journal handle
3158  * @inode: the file inode
3159  * @path: the path to the extent
3160  * @split: the logical block where the extent is splitted.
3161  * @split_flags: indicates if the extent could be zeroout if split fails, and
3162  *               the states(init or unwritten) of new extents.
3163  * @flags: flags used to insert new extent to extent tree.
3164  *
3165  *
3166  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3167  * of which are determined by split_flag.
3168  *
3169  * There are two cases:
3170  *  a> the extent are splitted into two extent.
3171  *  b> split is not needed, and just mark the extent.
3172  *
3173  * return 0 on success.
3174  */
3175 static int ext4_split_extent_at(handle_t *handle,
3176                              struct inode *inode,
3177                              struct ext4_ext_path **ppath,
3178                              ext4_lblk_t split,
3179                              int split_flag,
3180                              int flags)
3181 {
3182         struct ext4_ext_path *path = *ppath;
3183         ext4_fsblk_t newblock;
3184         ext4_lblk_t ee_block;
3185         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3186         struct ext4_extent *ex2 = NULL;
3187         unsigned int ee_len, depth;
3188         int err = 0;
3189
3190         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3191                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3192
3193         ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
3194
3195         ext4_ext_show_leaf(inode, path);
3196
3197         depth = ext_depth(inode);
3198         ex = path[depth].p_ext;
3199         ee_block = le32_to_cpu(ex->ee_block);
3200         ee_len = ext4_ext_get_actual_len(ex);
3201         newblock = split - ee_block + ext4_ext_pblock(ex);
3202
3203         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3204         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3205                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3206                              EXT4_EXT_MARK_UNWRIT1 |
3207                              EXT4_EXT_MARK_UNWRIT2));
3208
3209         err = ext4_ext_get_access(handle, inode, path + depth);
3210         if (err)
3211                 goto out;
3212
3213         if (split == ee_block) {
3214                 /*
3215                  * case b: block @split is the block that the extent begins with
3216                  * then we just change the state of the extent, and splitting
3217                  * is not needed.
3218                  */
3219                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3220                         ext4_ext_mark_unwritten(ex);
3221                 else
3222                         ext4_ext_mark_initialized(ex);
3223
3224                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3225                         ext4_ext_try_to_merge(handle, inode, path, ex);
3226
3227                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3228                 goto out;
3229         }
3230
3231         /* case a */
3232         memcpy(&orig_ex, ex, sizeof(orig_ex));
3233         ex->ee_len = cpu_to_le16(split - ee_block);
3234         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3235                 ext4_ext_mark_unwritten(ex);
3236
3237         /*
3238          * path may lead to new leaf, not to original leaf any more
3239          * after ext4_ext_insert_extent() returns,
3240          */
3241         err = ext4_ext_dirty(handle, inode, path + depth);
3242         if (err)
3243                 goto fix_extent_len;
3244
3245         ex2 = &newex;
3246         ex2->ee_block = cpu_to_le32(split);
3247         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3248         ext4_ext_store_pblock(ex2, newblock);
3249         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3250                 ext4_ext_mark_unwritten(ex2);
3251
3252         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3253         if (err != -ENOSPC && err != -EDQUOT)
3254                 goto out;
3255
3256         if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
3257                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3258                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3259                                 err = ext4_ext_zeroout(inode, ex2);
3260                                 zero_ex.ee_block = ex2->ee_block;
3261                                 zero_ex.ee_len = cpu_to_le16(
3262                                                 ext4_ext_get_actual_len(ex2));
3263                                 ext4_ext_store_pblock(&zero_ex,
3264                                                       ext4_ext_pblock(ex2));
3265                         } else {
3266                                 err = ext4_ext_zeroout(inode, ex);
3267                                 zero_ex.ee_block = ex->ee_block;
3268                                 zero_ex.ee_len = cpu_to_le16(
3269                                                 ext4_ext_get_actual_len(ex));
3270                                 ext4_ext_store_pblock(&zero_ex,
3271                                                       ext4_ext_pblock(ex));
3272                         }
3273                 } else {
3274                         err = ext4_ext_zeroout(inode, &orig_ex);
3275                         zero_ex.ee_block = orig_ex.ee_block;
3276                         zero_ex.ee_len = cpu_to_le16(
3277                                                 ext4_ext_get_actual_len(&orig_ex));
3278                         ext4_ext_store_pblock(&zero_ex,
3279                                               ext4_ext_pblock(&orig_ex));
3280                 }
3281
3282                 if (!err) {
3283                         /* update the extent length and mark as initialized */
3284                         ex->ee_len = cpu_to_le16(ee_len);
3285                         ext4_ext_try_to_merge(handle, inode, path, ex);
3286                         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3287                         if (!err)
3288                                 /* update extent status tree */
3289                                 err = ext4_zeroout_es(inode, &zero_ex);
3290                         /* If we failed at this point, we don't know in which
3291                          * state the extent tree exactly is so don't try to fix
3292                          * length of the original extent as it may do even more
3293                          * damage.
3294                          */
3295                         goto out;
3296                 }
3297         }
3298
3299 fix_extent_len:
3300         ex->ee_len = orig_ex.ee_len;
3301         /*
3302          * Ignore ext4_ext_dirty return value since we are already in error path
3303          * and err is a non-zero error code.
3304          */
3305         ext4_ext_dirty(handle, inode, path + path->p_depth);
3306         return err;
3307 out:
3308         ext4_ext_show_leaf(inode, path);
3309         return err;
3310 }
3311
3312 /*
3313  * ext4_split_extents() splits an extent and mark extent which is covered
3314  * by @map as split_flags indicates
3315  *
3316  * It may result in splitting the extent into multiple extents (up to three)
3317  * There are three possibilities:
3318  *   a> There is no split required
3319  *   b> Splits in two extents: Split is happening at either end of the extent
3320  *   c> Splits in three extents: Somone is splitting in middle of the extent
3321  *
3322  */
3323 static int ext4_split_extent(handle_t *handle,
3324                               struct inode *inode,
3325                               struct ext4_ext_path **ppath,
3326                               struct ext4_map_blocks *map,
3327                               int split_flag,
3328                               int flags)
3329 {
3330         struct ext4_ext_path *path = *ppath;
3331         ext4_lblk_t ee_block;
3332         struct ext4_extent *ex;
3333         unsigned int ee_len, depth;
3334         int err = 0;
3335         int unwritten;
3336         int split_flag1, flags1;
3337         int allocated = map->m_len;
3338
3339         depth = ext_depth(inode);
3340         ex = path[depth].p_ext;
3341         ee_block = le32_to_cpu(ex->ee_block);
3342         ee_len = ext4_ext_get_actual_len(ex);
3343         unwritten = ext4_ext_is_unwritten(ex);
3344
3345         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3346                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3347                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3348                 if (unwritten)
3349                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3350                                        EXT4_EXT_MARK_UNWRIT2;
3351                 if (split_flag & EXT4_EXT_DATA_VALID2)
3352                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3353                 err = ext4_split_extent_at(handle, inode, ppath,
3354                                 map->m_lblk + map->m_len, split_flag1, flags1);
3355                 if (err)
3356                         goto out;
3357         } else {
3358                 allocated = ee_len - (map->m_lblk - ee_block);
3359         }
3360         /*
3361          * Update path is required because previous ext4_split_extent_at() may
3362          * result in split of original leaf or extent zeroout.
3363          */
3364         path = ext4_find_extent(inode, map->m_lblk, ppath, flags);
3365         if (IS_ERR(path))
3366                 return PTR_ERR(path);
3367         depth = ext_depth(inode);
3368         ex = path[depth].p_ext;
3369         if (!ex) {
3370                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3371                                  (unsigned long) map->m_lblk);
3372                 return -EFSCORRUPTED;
3373         }
3374         unwritten = ext4_ext_is_unwritten(ex);
3375
3376         if (map->m_lblk >= ee_block) {
3377                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3378                 if (unwritten) {
3379                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3380                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3381                                                      EXT4_EXT_MARK_UNWRIT2);
3382                 }
3383                 err = ext4_split_extent_at(handle, inode, ppath,
3384                                 map->m_lblk, split_flag1, flags);
3385                 if (err)
3386                         goto out;
3387         }
3388
3389         ext4_ext_show_leaf(inode, path);
3390 out:
3391         return err ? err : allocated;
3392 }
3393
3394 /*
3395  * This function is called by ext4_ext_map_blocks() if someone tries to write
3396  * to an unwritten extent. It may result in splitting the unwritten
3397  * extent into multiple extents (up to three - one initialized and two
3398  * unwritten).
3399  * There are three possibilities:
3400  *   a> There is no split required: Entire extent should be initialized
3401  *   b> Splits in two extents: Write is happening at either end of the extent
3402  *   c> Splits in three extents: Somone is writing in middle of the extent
3403  *
3404  * Pre-conditions:
3405  *  - The extent pointed to by 'path' is unwritten.
3406  *  - The extent pointed to by 'path' contains a superset
3407  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3408  *
3409  * Post-conditions on success:
3410  *  - the returned value is the number of blocks beyond map->l_lblk
3411  *    that are allocated and initialized.
3412  *    It is guaranteed to be >= map->m_len.
3413  */
3414 static int ext4_ext_convert_to_initialized(handle_t *handle,
3415                                            struct inode *inode,
3416                                            struct ext4_map_blocks *map,
3417                                            struct ext4_ext_path **ppath,
3418                                            int flags)
3419 {
3420         struct ext4_ext_path *path = *ppath;
3421         struct ext4_sb_info *sbi;
3422         struct ext4_extent_header *eh;
3423         struct ext4_map_blocks split_map;
3424         struct ext4_extent zero_ex1, zero_ex2;
3425         struct ext4_extent *ex, *abut_ex;
3426         ext4_lblk_t ee_block, eof_block;
3427         unsigned int ee_len, depth, map_len = map->m_len;
3428         int allocated = 0, max_zeroout = 0;
3429         int err = 0;
3430         int split_flag = EXT4_EXT_DATA_VALID2;
3431
3432         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3433                   (unsigned long long)map->m_lblk, map_len);
3434
3435         sbi = EXT4_SB(inode->i_sb);
3436         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3437                         >> inode->i_sb->s_blocksize_bits;
3438         if (eof_block < map->m_lblk + map_len)
3439                 eof_block = map->m_lblk + map_len;
3440
3441         depth = ext_depth(inode);
3442         eh = path[depth].p_hdr;
3443         ex = path[depth].p_ext;
3444         ee_block = le32_to_cpu(ex->ee_block);
3445         ee_len = ext4_ext_get_actual_len(ex);
3446         zero_ex1.ee_len = 0;
3447         zero_ex2.ee_len = 0;
3448
3449         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3450
3451         /* Pre-conditions */
3452         BUG_ON(!ext4_ext_is_unwritten(ex));
3453         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3454
3455         /*
3456          * Attempt to transfer newly initialized blocks from the currently
3457          * unwritten extent to its neighbor. This is much cheaper
3458          * than an insertion followed by a merge as those involve costly
3459          * memmove() calls. Transferring to the left is the common case in
3460          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3461          * followed by append writes.
3462          *
3463          * Limitations of the current logic:
3464          *  - L1: we do not deal with writes covering the whole extent.
3465          *    This would require removing the extent if the transfer
3466          *    is possible.
3467          *  - L2: we only attempt to merge with an extent stored in the
3468          *    same extent tree node.
3469          */
3470         if ((map->m_lblk == ee_block) &&
3471                 /* See if we can merge left */
3472                 (map_len < ee_len) &&           /*L1*/
3473                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3474                 ext4_lblk_t prev_lblk;
3475                 ext4_fsblk_t prev_pblk, ee_pblk;
3476                 unsigned int prev_len;
3477
3478                 abut_ex = ex - 1;
3479                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3480                 prev_len = ext4_ext_get_actual_len(abut_ex);
3481                 prev_pblk = ext4_ext_pblock(abut_ex);
3482                 ee_pblk = ext4_ext_pblock(ex);
3483
3484                 /*
3485                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3486                  * upon those conditions:
3487                  * - C1: abut_ex is initialized,
3488                  * - C2: abut_ex is logically abutting ex,
3489                  * - C3: abut_ex is physically abutting ex,
3490                  * - C4: abut_ex can receive the additional blocks without
3491                  *   overflowing the (initialized) length limit.
3492                  */
3493                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3494                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3495                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3496                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3497                         err = ext4_ext_get_access(handle, inode, path + depth);
3498                         if (err)
3499                                 goto out;
3500
3501                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3502                                 map, ex, abut_ex);
3503
3504                         /* Shift the start of ex by 'map_len' blocks */
3505                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3506                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3507                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3508                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3509
3510                         /* Extend abut_ex by 'map_len' blocks */
3511                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3512
3513                         /* Result: number of initialized blocks past m_lblk */
3514                         allocated = map_len;
3515                 }
3516         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3517                    (map_len < ee_len) &&        /*L1*/
3518                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3519                 /* See if we can merge right */
3520                 ext4_lblk_t next_lblk;
3521                 ext4_fsblk_t next_pblk, ee_pblk;
3522                 unsigned int next_len;
3523
3524                 abut_ex = ex + 1;
3525                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3526                 next_len = ext4_ext_get_actual_len(abut_ex);
3527                 next_pblk = ext4_ext_pblock(abut_ex);
3528                 ee_pblk = ext4_ext_pblock(ex);
3529
3530                 /*
3531                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3532                  * upon those conditions:
3533                  * - C1: abut_ex is initialized,
3534                  * - C2: abut_ex is logically abutting ex,
3535                  * - C3: abut_ex is physically abutting ex,
3536                  * - C4: abut_ex can receive the additional blocks without
3537                  *   overflowing the (initialized) length limit.
3538                  */
3539                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3540                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3541                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3542                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3543                         err = ext4_ext_get_access(handle, inode, path + depth);
3544                         if (err)
3545                                 goto out;
3546
3547                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3548                                 map, ex, abut_ex);
3549
3550                         /* Shift the start of abut_ex by 'map_len' blocks */
3551                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3552                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3553                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3554                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3555
3556                         /* Extend abut_ex by 'map_len' blocks */
3557                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3558
3559                         /* Result: number of initialized blocks past m_lblk */
3560                         allocated = map_len;
3561                 }
3562         }
3563         if (allocated) {
3564                 /* Mark the block containing both extents as dirty */
3565                 err = ext4_ext_dirty(handle, inode, path + depth);
3566
3567                 /* Update path to point to the right extent */
3568                 path[depth].p_ext = abut_ex;
3569                 goto out;
3570         } else
3571                 allocated = ee_len - (map->m_lblk - ee_block);
3572
3573         WARN_ON(map->m_lblk < ee_block);
3574         /*
3575          * It is safe to convert extent to initialized via explicit
3576          * zeroout only if extent is fully inside i_size or new_size.
3577          */
3578         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3579
3580         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3581                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3582                         (inode->i_sb->s_blocksize_bits - 10);
3583
3584         /*
3585          * five cases:
3586          * 1. split the extent into three extents.
3587          * 2. split the extent into two extents, zeroout the head of the first
3588          *    extent.
3589          * 3. split the extent into two extents, zeroout the tail of the second
3590          *    extent.
3591          * 4. split the extent into two extents with out zeroout.
3592          * 5. no splitting needed, just possibly zeroout the head and / or the
3593          *    tail of the extent.
3594          */
3595         split_map.m_lblk = map->m_lblk;
3596         split_map.m_len = map->m_len;
3597
3598         if (max_zeroout && (allocated > split_map.m_len)) {
3599                 if (allocated <= max_zeroout) {
3600                         /* case 3 or 5 */
3601                         zero_ex1.ee_block =
3602                                  cpu_to_le32(split_map.m_lblk +
3603                                              split_map.m_len);
3604                         zero_ex1.ee_len =
3605                                 cpu_to_le16(allocated - split_map.m_len);
3606                         ext4_ext_store_pblock(&zero_ex1,
3607                                 ext4_ext_pblock(ex) + split_map.m_lblk +
3608                                 split_map.m_len - ee_block);
3609                         err = ext4_ext_zeroout(inode, &zero_ex1);
3610                         if (err)
3611                                 goto fallback;
3612                         split_map.m_len = allocated;
3613                 }
3614                 if (split_map.m_lblk - ee_block + split_map.m_len <
3615                                                                 max_zeroout) {
3616                         /* case 2 or 5 */
3617                         if (split_map.m_lblk != ee_block) {
3618                                 zero_ex2.ee_block = ex->ee_block;
3619                                 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3620                                                         ee_block);
3621                                 ext4_ext_store_pblock(&zero_ex2,
3622                                                       ext4_ext_pblock(ex));
3623                                 err = ext4_ext_zeroout(inode, &zero_ex2);
3624                                 if (err)
3625                                         goto fallback;
3626                         }
3627
3628                         split_map.m_len += split_map.m_lblk - ee_block;
3629                         split_map.m_lblk = ee_block;
3630                         allocated = map->m_len;
3631                 }
3632         }
3633
3634 fallback:
3635         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3636                                 flags);
3637         if (err > 0)
3638                 err = 0;
3639 out:
3640         /* If we have gotten a failure, don't zero out status tree */
3641         if (!err) {
3642                 err = ext4_zeroout_es(inode, &zero_ex1);
3643                 if (!err)
3644                         err = ext4_zeroout_es(inode, &zero_ex2);
3645         }
3646         return err ? err : allocated;
3647 }
3648
3649 /*
3650  * This function is called by ext4_ext_map_blocks() from
3651  * ext4_get_blocks_dio_write() when DIO to write
3652  * to an unwritten extent.
3653  *
3654  * Writing to an unwritten extent may result in splitting the unwritten
3655  * extent into multiple initialized/unwritten extents (up to three)
3656  * There are three possibilities:
3657  *   a> There is no split required: Entire extent should be unwritten
3658  *   b> Splits in two extents: Write is happening at either end of the extent
3659  *   c> Splits in three extents: Somone is writing in middle of the extent
3660  *
3661  * This works the same way in the case of initialized -> unwritten conversion.
3662  *
3663  * One of more index blocks maybe needed if the extent tree grow after
3664  * the unwritten extent split. To prevent ENOSPC occur at the IO
3665  * complete, we need to split the unwritten extent before DIO submit
3666  * the IO. The unwritten extent called at this time will be split
3667  * into three unwritten extent(at most). After IO complete, the part
3668  * being filled will be convert to initialized by the end_io callback function
3669  * via ext4_convert_unwritten_extents().
3670  *
3671  * Returns the size of unwritten extent to be written on success.
3672  */
3673 static int ext4_split_convert_extents(handle_t *handle,
3674                                         struct inode *inode,
3675                                         struct ext4_map_blocks *map,
3676                                         struct ext4_ext_path **ppath,
3677                                         int flags)
3678 {
3679         struct ext4_ext_path *path = *ppath;
3680         ext4_lblk_t eof_block;
3681         ext4_lblk_t ee_block;
3682         struct ext4_extent *ex;
3683         unsigned int ee_len;
3684         int split_flag = 0, depth;
3685
3686         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3687                   (unsigned long long)map->m_lblk, map->m_len);
3688
3689         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3690                         >> inode->i_sb->s_blocksize_bits;
3691         if (eof_block < map->m_lblk + map->m_len)
3692                 eof_block = map->m_lblk + map->m_len;
3693         /*
3694          * It is safe to convert extent to initialized via explicit
3695          * zeroout only if extent is fully inside i_size or new_size.
3696          */
3697         depth = ext_depth(inode);
3698         ex = path[depth].p_ext;
3699         ee_block = le32_to_cpu(ex->ee_block);
3700         ee_len = ext4_ext_get_actual_len(ex);
3701
3702         /* Convert to unwritten */
3703         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3704                 split_flag |= EXT4_EXT_DATA_VALID1;
3705         /* Convert to initialized */
3706         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3707                 split_flag |= ee_block + ee_len <= eof_block ?
3708                               EXT4_EXT_MAY_ZEROOUT : 0;
3709                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3710         }
3711         flags |= EXT4_GET_BLOCKS_PRE_IO;
3712         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3713 }
3714
3715 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3716                                                 struct inode *inode,
3717                                                 struct ext4_map_blocks *map,
3718                                                 struct ext4_ext_path **ppath)
3719 {
3720         struct ext4_ext_path *path = *ppath;
3721         struct ext4_extent *ex;
3722         ext4_lblk_t ee_block;
3723         unsigned int ee_len;
3724         int depth;
3725         int err = 0;
3726
3727         depth = ext_depth(inode);
3728         ex = path[depth].p_ext;
3729         ee_block = le32_to_cpu(ex->ee_block);
3730         ee_len = ext4_ext_get_actual_len(ex);
3731
3732         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3733                   (unsigned long long)ee_block, ee_len);
3734
3735         /* If extent is larger than requested it is a clear sign that we still
3736          * have some extent state machine issues left. So extent_split is still
3737          * required.
3738          * TODO: Once all related issues will be fixed this situation should be
3739          * illegal.
3740          */
3741         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3742 #ifdef CONFIG_EXT4_DEBUG
3743                 ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3744                              " len %u; IO logical block %llu, len %u",
3745                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3746                              (unsigned long long)map->m_lblk, map->m_len);
3747 #endif
3748                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3749                                                  EXT4_GET_BLOCKS_CONVERT);
3750                 if (err < 0)
3751                         return err;
3752                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3753                 if (IS_ERR(path))
3754                         return PTR_ERR(path);
3755                 depth = ext_depth(inode);
3756                 ex = path[depth].p_ext;
3757         }
3758
3759         err = ext4_ext_get_access(handle, inode, path + depth);
3760         if (err)
3761                 goto out;
3762         /* first mark the extent as initialized */
3763         ext4_ext_mark_initialized(ex);
3764
3765         /* note: ext4_ext_correct_indexes() isn't needed here because
3766          * borders are not changed
3767          */
3768         ext4_ext_try_to_merge(handle, inode, path, ex);
3769
3770         /* Mark modified extent as dirty */
3771         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3772 out:
3773         ext4_ext_show_leaf(inode, path);
3774         return err;
3775 }
3776
3777 static int
3778 convert_initialized_extent(handle_t *handle, struct inode *inode,
3779                            struct ext4_map_blocks *map,
3780                            struct ext4_ext_path **ppath,
3781                            unsigned int *allocated)
3782 {
3783         struct ext4_ext_path *path = *ppath;
3784         struct ext4_extent *ex;
3785         ext4_lblk_t ee_block;
3786         unsigned int ee_len;
3787         int depth;
3788         int err = 0;
3789
3790         /*
3791          * Make sure that the extent is no bigger than we support with
3792          * unwritten extent
3793          */
3794         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3795                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3796
3797         depth = ext_depth(inode);
3798         ex = path[depth].p_ext;
3799         ee_block = le32_to_cpu(ex->ee_block);
3800         ee_len = ext4_ext_get_actual_len(ex);
3801
3802         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3803                   (unsigned long long)ee_block, ee_len);
3804
3805         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3806                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3807                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3808                 if (err < 0)
3809                         return err;
3810                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3811                 if (IS_ERR(path))
3812                         return PTR_ERR(path);
3813                 depth = ext_depth(inode);
3814                 ex = path[depth].p_ext;
3815                 if (!ex) {
3816                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3817                                          (unsigned long) map->m_lblk);
3818                         return -EFSCORRUPTED;
3819                 }
3820         }
3821
3822         err = ext4_ext_get_access(handle, inode, path + depth);
3823         if (err)
3824                 return err;
3825         /* first mark the extent as unwritten */
3826         ext4_ext_mark_unwritten(ex);
3827
3828         /* note: ext4_ext_correct_indexes() isn't needed here because
3829          * borders are not changed
3830          */
3831         ext4_ext_try_to_merge(handle, inode, path, ex);
3832
3833         /* Mark modified extent as dirty */
3834         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3835         if (err)
3836                 return err;
3837         ext4_ext_show_leaf(inode, path);
3838
3839         ext4_update_inode_fsync_trans(handle, inode, 1);
3840
3841         map->m_flags |= EXT4_MAP_UNWRITTEN;
3842         if (*allocated > map->m_len)
3843                 *allocated = map->m_len;
3844         map->m_len = *allocated;
3845         return 0;
3846 }
3847
3848 static int
3849 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3850                         struct ext4_map_blocks *map,
3851                         struct ext4_ext_path **ppath, int flags,
3852                         unsigned int allocated, ext4_fsblk_t newblock)
3853 {
3854         struct ext4_ext_path __maybe_unused *path = *ppath;
3855         int ret = 0;
3856         int err = 0;
3857
3858         ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
3859                   (unsigned long long)map->m_lblk, map->m_len, flags,
3860                   allocated);
3861         ext4_ext_show_leaf(inode, path);
3862
3863         /*
3864          * When writing into unwritten space, we should not fail to
3865          * allocate metadata blocks for the new extent block if needed.
3866          */
3867         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3868
3869         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
3870                                                     allocated, newblock);
3871
3872         /* get_block() before submitting IO, split the extent */
3873         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
3874                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
3875                                          flags | EXT4_GET_BLOCKS_CONVERT);
3876                 if (ret < 0) {
3877                         err = ret;
3878                         goto out2;
3879                 }
3880                 /*
3881                  * shouldn't get a 0 return when splitting an extent unless
3882                  * m_len is 0 (bug) or extent has been corrupted
3883                  */
3884                 if (unlikely(ret == 0)) {
3885                         EXT4_ERROR_INODE(inode,
3886                                          "unexpected ret == 0, m_len = %u",
3887                                          map->m_len);
3888                         err = -EFSCORRUPTED;
3889                         goto out2;
3890                 }
3891                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3892                 goto out;
3893         }
3894         /* IO end_io complete, convert the filled extent to written */
3895         if (flags & EXT4_GET_BLOCKS_CONVERT) {
3896                 err = ext4_convert_unwritten_extents_endio(handle, inode, map,
3897                                                            ppath);
3898                 if (err < 0)
3899                         goto out2;
3900                 ext4_update_inode_fsync_trans(handle, inode, 1);
3901                 goto map_out;
3902         }
3903         /* buffered IO cases */
3904         /*
3905          * repeat fallocate creation request
3906          * we already have an unwritten extent
3907          */
3908         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
3909                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3910                 goto map_out;
3911         }
3912
3913         /* buffered READ or buffered write_begin() lookup */
3914         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3915                 /*
3916                  * We have blocks reserved already.  We
3917                  * return allocated blocks so that delalloc
3918                  * won't do block reservation for us.  But
3919                  * the buffer head will be unmapped so that
3920                  * a read from the block returns 0s.
3921                  */
3922                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3923                 goto out1;
3924         }
3925
3926         /*
3927          * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
3928          * For buffered writes, at writepage time, etc.  Convert a
3929          * discovered unwritten extent to written.
3930          */
3931         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
3932         if (ret < 0) {
3933                 err = ret;
3934                 goto out2;
3935         }
3936         ext4_update_inode_fsync_trans(handle, inode, 1);
3937         /*
3938          * shouldn't get a 0 return when converting an unwritten extent
3939          * unless m_len is 0 (bug) or extent has been corrupted
3940          */
3941         if (unlikely(ret == 0)) {
3942                 EXT4_ERROR_INODE(inode, "unexpected ret == 0, m_len = %u",
3943                                  map->m_len);
3944                 err = -EFSCORRUPTED;
3945                 goto out2;
3946         }
3947
3948 out:
3949         allocated = ret;
3950         map->m_flags |= EXT4_MAP_NEW;
3951 map_out:
3952         map->m_flags |= EXT4_MAP_MAPPED;
3953 out1:
3954         map->m_pblk = newblock;
3955         if (allocated > map->m_len)
3956                 allocated = map->m_len;
3957         map->m_len = allocated;
3958         ext4_ext_show_leaf(inode, path);
3959 out2:
3960         return err ? err : allocated;
3961 }
3962
3963 /*
3964  * get_implied_cluster_alloc - check to see if the requested
3965  * allocation (in the map structure) overlaps with a cluster already
3966  * allocated in an extent.
3967  *      @sb     The filesystem superblock structure
3968  *      @map    The requested lblk->pblk mapping
3969  *      @ex     The extent structure which might contain an implied
3970  *                      cluster allocation
3971  *
3972  * This function is called by ext4_ext_map_blocks() after we failed to
3973  * find blocks that were already in the inode's extent tree.  Hence,
3974  * we know that the beginning of the requested region cannot overlap
3975  * the extent from the inode's extent tree.  There are three cases we
3976  * want to catch.  The first is this case:
3977  *
3978  *               |--- cluster # N--|
3979  *    |--- extent ---|  |---- requested region ---|
3980  *                      |==========|
3981  *
3982  * The second case that we need to test for is this one:
3983  *
3984  *   |--------- cluster # N ----------------|
3985  *         |--- requested region --|   |------- extent ----|
3986  *         |=======================|
3987  *
3988  * The third case is when the requested region lies between two extents
3989  * within the same cluster:
3990  *          |------------- cluster # N-------------|
3991  * |----- ex -----|                  |---- ex_right ----|
3992  *                  |------ requested region ------|
3993  *                  |================|
3994  *
3995  * In each of the above cases, we need to set the map->m_pblk and
3996  * map->m_len so it corresponds to the return the extent labelled as
3997  * "|====|" from cluster #N, since it is already in use for data in
3998  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
3999  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4000  * as a new "allocated" block region.  Otherwise, we will return 0 and
4001  * ext4_ext_map_blocks() will then allocate one or more new clusters
4002  * by calling ext4_mb_new_blocks().
4003  */
4004 static int get_implied_cluster_alloc(struct super_block *sb,
4005                                      struct ext4_map_blocks *map,
4006                                      struct ext4_extent *ex,
4007                                      struct ext4_ext_path *path)
4008 {
4009         struct ext4_sb_info *sbi = EXT4_SB(sb);
4010         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4011         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4012         ext4_lblk_t rr_cluster_start;
4013         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4014         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4015         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4016
4017         /* The extent passed in that we are trying to match */
4018         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4019         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4020
4021         /* The requested region passed into ext4_map_blocks() */
4022         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4023
4024         if ((rr_cluster_start == ex_cluster_end) ||
4025             (rr_cluster_start == ex_cluster_start)) {
4026                 if (rr_cluster_start == ex_cluster_end)
4027                         ee_start += ee_len - 1;
4028                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4029                 map->m_len = min(map->m_len,
4030                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4031                 /*
4032                  * Check for and handle this case:
4033                  *
4034                  *   |--------- cluster # N-------------|
4035                  *                     |------- extent ----|
4036                  *         |--- requested region ---|
4037                  *         |===========|
4038                  */
4039
4040                 if (map->m_lblk < ee_block)
4041                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4042
4043                 /*
4044                  * Check for the case where there is already another allocated
4045                  * block to the right of 'ex' but before the end of the cluster.
4046                  *
4047                  *          |------------- cluster # N-------------|
4048                  * |----- ex -----|                  |---- ex_right ----|
4049                  *                  |------ requested region ------|
4050                  *                  |================|
4051                  */
4052                 if (map->m_lblk > ee_block) {
4053                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4054                         map->m_len = min(map->m_len, next - map->m_lblk);
4055                 }
4056
4057                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4058                 return 1;
4059         }
4060
4061         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4062         return 0;
4063 }
4064
4065
4066 /*
4067  * Block allocation/map/preallocation routine for extents based files
4068  *
4069  *
4070  * Need to be called with
4071  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4072  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4073  *
4074  * return > 0, number of blocks already mapped/allocated
4075  *          if create == 0 and these are pre-allocated blocks
4076  *              buffer head is unmapped
4077  *          otherwise blocks are mapped
4078  *
4079  * return = 0, if plain look up failed (blocks have not been allocated)
4080  *          buffer head is unmapped
4081  *
4082  * return < 0, error case.
4083  */
4084 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4085                         struct ext4_map_blocks *map, int flags)
4086 {
4087         struct ext4_ext_path *path = NULL;
4088         struct ext4_extent newex, *ex, ex2;
4089         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4090         ext4_fsblk_t newblock = 0, pblk;
4091         int err = 0, depth, ret;
4092         unsigned int allocated = 0, offset = 0;
4093         unsigned int allocated_clusters = 0;
4094         struct ext4_allocation_request ar;
4095         ext4_lblk_t cluster_offset;
4096
4097         ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
4098         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4099
4100         /* find extent for this block */
4101         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4102         if (IS_ERR(path)) {
4103                 err = PTR_ERR(path);
4104                 path = NULL;
4105                 goto out;
4106         }
4107
4108         depth = ext_depth(inode);
4109
4110         /*
4111          * consistent leaf must not be empty;
4112          * this situation is possible, though, _during_ tree modification;
4113          * this is why assert can't be put in ext4_find_extent()
4114          */
4115         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4116                 EXT4_ERROR_INODE(inode, "bad extent address "
4117                                  "lblock: %lu, depth: %d pblock %lld",
4118                                  (unsigned long) map->m_lblk, depth,
4119                                  path[depth].p_block);
4120                 err = -EFSCORRUPTED;
4121                 goto out;
4122         }
4123
4124         ex = path[depth].p_ext;
4125         if (ex) {
4126                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4127                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4128                 unsigned short ee_len;
4129
4130
4131                 /*
4132                  * unwritten extents are treated as holes, except that
4133                  * we split out initialized portions during a write.
4134                  */
4135                 ee_len = ext4_ext_get_actual_len(ex);
4136
4137                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4138
4139                 /* if found extent covers block, simply return it */
4140                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4141                         newblock = map->m_lblk - ee_block + ee_start;
4142                         /* number of remaining blocks in the extent */
4143                         allocated = ee_len - (map->m_lblk - ee_block);
4144                         ext_debug(inode, "%u fit into %u:%d -> %llu\n",
4145                                   map->m_lblk, ee_block, ee_len, newblock);
4146
4147                         /*
4148                          * If the extent is initialized check whether the
4149                          * caller wants to convert it to unwritten.
4150                          */
4151                         if ((!ext4_ext_is_unwritten(ex)) &&
4152                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4153                                 err = convert_initialized_extent(handle,
4154                                         inode, map, &path, &allocated);
4155                                 goto out;
4156                         } else if (!ext4_ext_is_unwritten(ex)) {
4157                                 map->m_flags |= EXT4_MAP_MAPPED;
4158                                 map->m_pblk = newblock;
4159                                 if (allocated > map->m_len)
4160                                         allocated = map->m_len;
4161                                 map->m_len = allocated;
4162                                 ext4_ext_show_leaf(inode, path);
4163                                 goto out;
4164                         }
4165
4166                         ret = ext4_ext_handle_unwritten_extents(
4167                                 handle, inode, map, &path, flags,
4168                                 allocated, newblock);
4169                         if (ret < 0)
4170                                 err = ret;
4171                         else
4172                                 allocated = ret;
4173                         goto out;
4174                 }
4175         }
4176
4177         /*
4178          * requested block isn't allocated yet;
4179          * we couldn't try to create block if create flag is zero
4180          */
4181         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4182                 ext4_lblk_t hole_start, hole_len;
4183
4184                 hole_start = map->m_lblk;
4185                 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4186                 /*
4187                  * put just found gap into cache to speed up
4188                  * subsequent requests
4189                  */
4190                 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4191
4192                 /* Update hole_len to reflect hole size after map->m_lblk */
4193                 if (hole_start != map->m_lblk)
4194                         hole_len -= map->m_lblk - hole_start;
4195                 map->m_pblk = 0;
4196                 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4197
4198                 goto out;
4199         }
4200
4201         /*
4202          * Okay, we need to do block allocation.
4203          */
4204         newex.ee_block = cpu_to_le32(map->m_lblk);
4205         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4206
4207         /*
4208          * If we are doing bigalloc, check to see if the extent returned
4209          * by ext4_find_extent() implies a cluster we can use.
4210          */
4211         if (cluster_offset && ex &&
4212             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4213                 ar.len = allocated = map->m_len;
4214                 newblock = map->m_pblk;
4215                 goto got_allocated_blocks;
4216         }
4217
4218         /* find neighbour allocated blocks */
4219         ar.lleft = map->m_lblk;
4220         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4221         if (err)
4222                 goto out;
4223         ar.lright = map->m_lblk;
4224         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4225         if (err < 0)
4226                 goto out;
4227
4228         /* Check if the extent after searching to the right implies a
4229          * cluster we can use. */
4230         if ((sbi->s_cluster_ratio > 1) && err &&
4231             get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
4232                 ar.len = allocated = map->m_len;
4233                 newblock = map->m_pblk;
4234                 goto got_allocated_blocks;
4235         }
4236
4237         /*
4238          * See if request is beyond maximum number of blocks we can have in
4239          * a single extent. For an initialized extent this limit is
4240          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4241          * EXT_UNWRITTEN_MAX_LEN.
4242          */
4243         if (map->m_len > EXT_INIT_MAX_LEN &&
4244             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4245                 map->m_len = EXT_INIT_MAX_LEN;
4246         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4247                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4248                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4249
4250         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4251         newex.ee_len = cpu_to_le16(map->m_len);
4252         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4253         if (err)
4254                 allocated = ext4_ext_get_actual_len(&newex);
4255         else
4256                 allocated = map->m_len;
4257
4258         /* allocate new block */
4259         ar.inode = inode;
4260         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4261         ar.logical = map->m_lblk;
4262         /*
4263          * We calculate the offset from the beginning of the cluster
4264          * for the logical block number, since when we allocate a
4265          * physical cluster, the physical block should start at the
4266          * same offset from the beginning of the cluster.  This is
4267          * needed so that future calls to get_implied_cluster_alloc()
4268          * work correctly.
4269          */
4270         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4271         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4272         ar.goal -= offset;
4273         ar.logical -= offset;
4274         if (S_ISREG(inode->i_mode))
4275                 ar.flags = EXT4_MB_HINT_DATA;
4276         else
4277                 /* disable in-core preallocation for non-regular files */
4278                 ar.flags = 0;
4279         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4280                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4281         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4282                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4283         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4284                 ar.flags |= EXT4_MB_USE_RESERVED;
4285         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4286         if (!newblock)
4287                 goto out;
4288         allocated_clusters = ar.len;
4289         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4290         ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
4291                   ar.goal, newblock, ar.len, allocated);
4292         if (ar.len > allocated)
4293                 ar.len = allocated;
4294
4295 got_allocated_blocks:
4296         /* try to insert new extent into found leaf and return */
4297         pblk = newblock + offset;
4298         ext4_ext_store_pblock(&newex, pblk);
4299         newex.ee_len = cpu_to_le16(ar.len);
4300         /* Mark unwritten */
4301         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4302                 ext4_ext_mark_unwritten(&newex);
4303                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4304         }
4305
4306         err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags);
4307         if (err) {
4308                 if (allocated_clusters) {
4309                         int fb_flags = 0;
4310
4311                         /*
4312                          * free data blocks we just allocated.
4313                          * not a good idea to call discard here directly,
4314                          * but otherwise we'd need to call it every free().
4315                          */
4316                         ext4_discard_preallocations(inode, 0);
4317                         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4318                                 fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
4319                         ext4_free_blocks(handle, inode, NULL, newblock,
4320                                          EXT4_C2B(sbi, allocated_clusters),
4321                                          fb_flags);
4322                 }
4323                 goto out;
4324         }
4325
4326         /*
4327          * Reduce the reserved cluster count to reflect successful deferred
4328          * allocation of delayed allocated clusters or direct allocation of
4329          * clusters discovered to be delayed allocated.  Once allocated, a
4330          * cluster is not included in the reserved count.
4331          */
4332         if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
4333                 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4334                         /*
4335                          * When allocating delayed allocated clusters, simply
4336                          * reduce the reserved cluster count and claim quota
4337                          */
4338                         ext4_da_update_reserve_space(inode, allocated_clusters,
4339                                                         1);
4340                 } else {
4341                         ext4_lblk_t lblk, len;
4342                         unsigned int n;
4343
4344                         /*
4345                          * When allocating non-delayed allocated clusters
4346                          * (from fallocate, filemap, DIO, or clusters
4347                          * allocated when delalloc has been disabled by
4348                          * ext4_nonda_switch), reduce the reserved cluster
4349                          * count by the number of allocated clusters that
4350                          * have previously been delayed allocated.  Quota
4351                          * has been claimed by ext4_mb_new_blocks() above,
4352                          * so release the quota reservations made for any
4353                          * previously delayed allocated clusters.
4354                          */
4355                         lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4356                         len = allocated_clusters << sbi->s_cluster_bits;
4357                         n = ext4_es_delayed_clu(inode, lblk, len);
4358                         if (n > 0)
4359                                 ext4_da_update_reserve_space(inode, (int) n, 0);
4360                 }
4361         }
4362
4363         /*
4364          * Cache the extent and update transaction to commit on fdatasync only
4365          * when it is _not_ an unwritten extent.
4366          */
4367         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4368                 ext4_update_inode_fsync_trans(handle, inode, 1);
4369         else
4370                 ext4_update_inode_fsync_trans(handle, inode, 0);
4371
4372         map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
4373         map->m_pblk = pblk;
4374         map->m_len = ar.len;
4375         allocated = map->m_len;
4376         ext4_ext_show_leaf(inode, path);
4377 out:
4378         ext4_ext_drop_refs(path);
4379         kfree(path);
4380
4381         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4382                                        err ? err : allocated);
4383         return err ? err : allocated;
4384 }
4385
4386 int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4387 {
4388         struct super_block *sb = inode->i_sb;
4389         ext4_lblk_t last_block;
4390         int err = 0;
4391
4392         /*
4393          * TODO: optimization is possible here.
4394          * Probably we need not scan at all,
4395          * because page truncation is enough.
4396          */
4397
4398         /* we have to know where to truncate from in crash case */
4399         EXT4_I(inode)->i_disksize = inode->i_size;
4400         err = ext4_mark_inode_dirty(handle, inode);
4401         if (err)
4402                 return err;
4403
4404         last_block = (inode->i_size + sb->s_blocksize - 1)
4405                         >> EXT4_BLOCK_SIZE_BITS(sb);
4406 retry:
4407         err = ext4_es_remove_extent(inode, last_block,
4408                                     EXT_MAX_BLOCKS - last_block);
4409         if (err == -ENOMEM) {
4410                 memalloc_retry_wait(GFP_ATOMIC);
4411                 goto retry;
4412         }
4413         if (err)
4414                 return err;
4415 retry_remove_space:
4416         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4417         if (err == -ENOMEM) {
4418                 memalloc_retry_wait(GFP_ATOMIC);
4419                 goto retry_remove_space;
4420         }
4421         return err;
4422 }
4423
4424 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4425                                   ext4_lblk_t len, loff_t new_size,
4426                                   int flags)
4427 {
4428         struct inode *inode = file_inode(file);
4429         handle_t *handle;
4430         int ret = 0, ret2 = 0, ret3 = 0;
4431         int retries = 0;
4432         int depth = 0;
4433         struct ext4_map_blocks map;
4434         unsigned int credits;
4435         loff_t epos;
4436
4437         BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4438         map.m_lblk = offset;
4439         map.m_len = len;
4440         /*
4441          * Don't normalize the request if it can fit in one extent so
4442          * that it doesn't get unnecessarily split into multiple
4443          * extents.
4444          */
4445         if (len <= EXT_UNWRITTEN_MAX_LEN)
4446                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4447
4448         /*
4449          * credits to insert 1 extent into extent tree
4450          */
4451         credits = ext4_chunk_trans_blocks(inode, len);
4452         depth = ext_depth(inode);
4453
4454 retry:
4455         while (len) {
4456                 /*
4457                  * Recalculate credits when extent tree depth changes.
4458                  */
4459                 if (depth != ext_depth(inode)) {
4460                         credits = ext4_chunk_trans_blocks(inode, len);
4461                         depth = ext_depth(inode);
4462                 }
4463
4464                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4465                                             credits);
4466                 if (IS_ERR(handle)) {
4467                         ret = PTR_ERR(handle);
4468                         break;
4469                 }
4470                 ret = ext4_map_blocks(handle, inode, &map, flags);
4471                 if (ret <= 0) {
4472                         ext4_debug("inode #%lu: block %u: len %u: "
4473                                    "ext4_ext_map_blocks returned %d",
4474                                    inode->i_ino, map.m_lblk,
4475                                    map.m_len, ret);
4476                         ext4_mark_inode_dirty(handle, inode);
4477                         ext4_journal_stop(handle);
4478                         break;
4479                 }
4480                 /*
4481                  * allow a full retry cycle for any remaining allocations
4482                  */
4483                 retries = 0;
4484                 map.m_lblk += ret;
4485                 map.m_len = len = len - ret;
4486                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4487                 inode->i_ctime = current_time(inode);
4488                 if (new_size) {
4489                         if (epos > new_size)
4490                                 epos = new_size;
4491                         if (ext4_update_inode_size(inode, epos) & 0x1)
4492                                 inode->i_mtime = inode->i_ctime;
4493                 }
4494                 ret2 = ext4_mark_inode_dirty(handle, inode);
4495                 ext4_update_inode_fsync_trans(handle, inode, 1);
4496                 ret3 = ext4_journal_stop(handle);
4497                 ret2 = ret3 ? ret3 : ret2;
4498                 if (unlikely(ret2))
4499                         break;
4500         }
4501         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
4502                 goto retry;
4503
4504         return ret > 0 ? ret2 : ret;
4505 }
4506
4507 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);
4508
4509 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
4510
4511 static long ext4_zero_range(struct file *file, loff_t offset,
4512                             loff_t len, int mode)
4513 {
4514         struct inode *inode = file_inode(file);
4515         struct address_space *mapping = file->f_mapping;
4516         handle_t *handle = NULL;
4517         unsigned int max_blocks;
4518         loff_t new_size = 0;
4519         int ret = 0;
4520         int flags;
4521         int credits;
4522         int partial_begin, partial_end;
4523         loff_t start, end;
4524         ext4_lblk_t lblk;
4525         unsigned int blkbits = inode->i_blkbits;
4526
4527         trace_ext4_zero_range(inode, offset, len, mode);
4528
4529         /* Call ext4_force_commit to flush all data in case of data=journal. */
4530         if (ext4_should_journal_data(inode)) {
4531                 ret = ext4_force_commit(inode->i_sb);
4532                 if (ret)
4533                         return ret;
4534         }
4535
4536         /*
4537          * Round up offset. This is not fallocate, we need to zero out
4538          * blocks, so convert interior block aligned part of the range to
4539          * unwritten and possibly manually zero out unaligned parts of the
4540          * range.
4541          */
4542         start = round_up(offset, 1 << blkbits);
4543         end = round_down((offset + len), 1 << blkbits);
4544
4545         if (start < offset || end > offset + len)
4546                 return -EINVAL;
4547         partial_begin = offset & ((1 << blkbits) - 1);
4548         partial_end = (offset + len) & ((1 << blkbits) - 1);
4549
4550         lblk = start >> blkbits;
4551         max_blocks = (end >> blkbits);
4552         if (max_blocks < lblk)
4553                 max_blocks = 0;
4554         else
4555                 max_blocks -= lblk;
4556
4557         inode_lock(inode);
4558
4559         /*
4560          * Indirect files do not support unwritten extents
4561          */
4562         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4563                 ret = -EOPNOTSUPP;
4564                 goto out_mutex;
4565         }
4566
4567         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4568             (offset + len > inode->i_size ||
4569              offset + len > EXT4_I(inode)->i_disksize)) {
4570                 new_size = offset + len;
4571                 ret = inode_newsize_ok(inode, new_size);
4572                 if (ret)
4573                         goto out_mutex;
4574         }
4575
4576         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4577
4578         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4579         inode_dio_wait(inode);
4580
4581         ret = file_modified(file);
4582         if (ret)
4583                 goto out_mutex;
4584
4585         /* Preallocate the range including the unaligned edges */
4586         if (partial_begin || partial_end) {
4587                 ret = ext4_alloc_file_blocks(file,
4588                                 round_down(offset, 1 << blkbits) >> blkbits,
4589                                 (round_up((offset + len), 1 << blkbits) -
4590                                  round_down(offset, 1 << blkbits)) >> blkbits,
4591                                 new_size, flags);
4592                 if (ret)
4593                         goto out_mutex;
4594
4595         }
4596
4597         /* Zero range excluding the unaligned edges */
4598         if (max_blocks > 0) {
4599                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4600                           EXT4_EX_NOCACHE);
4601
4602                 /*
4603                  * Prevent page faults from reinstantiating pages we have
4604                  * released from page cache.
4605                  */
4606                 filemap_invalidate_lock(mapping);
4607
4608                 ret = ext4_break_layouts(inode);
4609                 if (ret) {
4610                         filemap_invalidate_unlock(mapping);
4611                         goto out_mutex;
4612                 }
4613
4614                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4615                 if (ret) {
4616                         filemap_invalidate_unlock(mapping);
4617                         goto out_mutex;
4618                 }
4619                 /* Now release the pages and zero block aligned part of pages */
4620                 truncate_pagecache_range(inode, start, end - 1);
4621                 inode->i_mtime = inode->i_ctime = current_time(inode);
4622
4623                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4624                                              flags);
4625                 filemap_invalidate_unlock(mapping);
4626                 if (ret)
4627                         goto out_mutex;
4628         }
4629         if (!partial_begin && !partial_end)
4630                 goto out_mutex;
4631
4632         /*
4633          * In worst case we have to writeout two nonadjacent unwritten
4634          * blocks and update the inode
4635          */
4636         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4637         if (ext4_should_journal_data(inode))
4638                 credits += 2;
4639         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4640         if (IS_ERR(handle)) {
4641                 ret = PTR_ERR(handle);
4642                 ext4_std_error(inode->i_sb, ret);
4643                 goto out_mutex;
4644         }
4645
4646         inode->i_mtime = inode->i_ctime = current_time(inode);
4647         if (new_size)
4648                 ext4_update_inode_size(inode, new_size);
4649         ret = ext4_mark_inode_dirty(handle, inode);
4650         if (unlikely(ret))
4651                 goto out_handle;
4652         /* Zero out partial block at the edges of the range */
4653         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4654         if (ret >= 0)
4655                 ext4_update_inode_fsync_trans(handle, inode, 1);
4656
4657         if (file->f_flags & O_SYNC)
4658                 ext4_handle_sync(handle);
4659
4660 out_handle:
4661         ext4_journal_stop(handle);
4662 out_mutex:
4663         inode_unlock(inode);
4664         return ret;
4665 }
4666
4667 /*
4668  * preallocate space for a file. This implements ext4's fallocate file
4669  * operation, which gets called from sys_fallocate system call.
4670  * For block-mapped files, posix_fallocate should fall back to the method
4671  * of writing zeroes to the required new blocks (the same behavior which is
4672  * expected for file systems which do not support fallocate() system call).
4673  */
4674 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4675 {
4676         struct inode *inode = file_inode(file);
4677         loff_t new_size = 0;
4678         unsigned int max_blocks;
4679         int ret = 0;
4680         int flags;
4681         ext4_lblk_t lblk;
4682         unsigned int blkbits = inode->i_blkbits;
4683
4684         /*
4685          * Encrypted inodes can't handle collapse range or insert
4686          * range since we would need to re-encrypt blocks with a
4687          * different IV or XTS tweak (which are based on the logical
4688          * block number).
4689          */
4690         if (IS_ENCRYPTED(inode) &&
4691             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
4692                 return -EOPNOTSUPP;
4693
4694         /* Return error if mode is not supported */
4695         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4696                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4697                      FALLOC_FL_INSERT_RANGE))
4698                 return -EOPNOTSUPP;
4699
4700         inode_lock(inode);
4701         ret = ext4_convert_inline_data(inode);
4702         inode_unlock(inode);
4703         if (ret)
4704                 goto exit;
4705
4706         if (mode & FALLOC_FL_PUNCH_HOLE) {
4707                 ret = ext4_punch_hole(file, offset, len);
4708                 goto exit;
4709         }
4710
4711         if (mode & FALLOC_FL_COLLAPSE_RANGE) {
4712                 ret = ext4_collapse_range(file, offset, len);
4713                 goto exit;
4714         }
4715
4716         if (mode & FALLOC_FL_INSERT_RANGE) {
4717                 ret = ext4_insert_range(file, offset, len);
4718                 goto exit;
4719         }
4720
4721         if (mode & FALLOC_FL_ZERO_RANGE) {
4722                 ret = ext4_zero_range(file, offset, len, mode);
4723                 goto exit;
4724         }
4725         trace_ext4_fallocate_enter(inode, offset, len, mode);
4726         lblk = offset >> blkbits;
4727
4728         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4729         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4730
4731         inode_lock(inode);
4732
4733         /*
4734          * We only support preallocation for extent-based files only
4735          */
4736         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4737                 ret = -EOPNOTSUPP;
4738                 goto out;
4739         }
4740
4741         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4742             (offset + len > inode->i_size ||
4743              offset + len > EXT4_I(inode)->i_disksize)) {
4744                 new_size = offset + len;
4745                 ret = inode_newsize_ok(inode, new_size);
4746                 if (ret)
4747                         goto out;
4748         }
4749
4750         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4751         inode_dio_wait(inode);
4752
4753         ret = file_modified(file);
4754         if (ret)
4755                 goto out;
4756
4757         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4758         if (ret)
4759                 goto out;
4760
4761         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4762                 ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
4763                                         EXT4_I(inode)->i_sync_tid);
4764         }
4765 out:
4766         inode_unlock(inode);
4767         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4768 exit:
4769         return ret;
4770 }
4771
4772 /*
4773  * This function convert a range of blocks to written extents
4774  * The caller of this function will pass the start offset and the size.
4775  * all unwritten extents within this range will be converted to
4776  * written extents.
4777  *
4778  * This function is called from the direct IO end io call back
4779  * function, to convert the fallocated extents after IO is completed.
4780  * Returns 0 on success.
4781  */
4782 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4783                                    loff_t offset, ssize_t len)
4784 {
4785         unsigned int max_blocks;
4786         int ret = 0, ret2 = 0, ret3 = 0;
4787         struct ext4_map_blocks map;
4788         unsigned int blkbits = inode->i_blkbits;
4789         unsigned int credits = 0;
4790
4791         map.m_lblk = offset >> blkbits;
4792         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4793
4794         if (!handle) {
4795                 /*
4796                  * credits to insert 1 extent into extent tree
4797                  */
4798                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4799         }
4800         while (ret >= 0 && ret < max_blocks) {
4801                 map.m_lblk += ret;
4802                 map.m_len = (max_blocks -= ret);
4803                 if (credits) {
4804                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4805                                                     credits);
4806                         if (IS_ERR(handle)) {
4807                                 ret = PTR_ERR(handle);
4808                                 break;
4809                         }
4810                 }
4811                 ret = ext4_map_blocks(handle, inode, &map,
4812                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4813                 if (ret <= 0)
4814                         ext4_warning(inode->i_sb,
4815                                      "inode #%lu: block %u: len %u: "
4816                                      "ext4_ext_map_blocks returned %d",
4817                                      inode->i_ino, map.m_lblk,
4818                                      map.m_len, ret);
4819                 ret2 = ext4_mark_inode_dirty(handle, inode);
4820                 if (credits) {
4821                         ret3 = ext4_journal_stop(handle);
4822                         if (unlikely(ret3))
4823                                 ret2 = ret3;
4824                 }
4825
4826                 if (ret <= 0 || ret2)
4827                         break;
4828         }
4829         return ret > 0 ? ret2 : ret;
4830 }
4831
4832 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
4833 {
4834         int ret = 0, err = 0;
4835         struct ext4_io_end_vec *io_end_vec;
4836
4837         /*
4838          * This is somewhat ugly but the idea is clear: When transaction is
4839          * reserved, everything goes into it. Otherwise we rather start several
4840          * smaller transactions for conversion of each extent separately.
4841          */
4842         if (handle) {
4843                 handle = ext4_journal_start_reserved(handle,
4844                                                      EXT4_HT_EXT_CONVERT);
4845                 if (IS_ERR(handle))
4846                         return PTR_ERR(handle);
4847         }
4848
4849         list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4850                 ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4851                                                      io_end_vec->offset,
4852                                                      io_end_vec->size);
4853                 if (ret)
4854                         break;
4855         }
4856
4857         if (handle)
4858                 err = ext4_journal_stop(handle);
4859
4860         return ret < 0 ? ret : err;
4861 }
4862
4863 static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
4864 {
4865         __u64 physical = 0;
4866         __u64 length = 0;
4867         int blockbits = inode->i_sb->s_blocksize_bits;
4868         int error = 0;
4869         u16 iomap_type;
4870
4871         /* in-inode? */
4872         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4873                 struct ext4_iloc iloc;
4874                 int offset;     /* offset of xattr in inode */
4875
4876                 error = ext4_get_inode_loc(inode, &iloc);
4877                 if (error)
4878                         return error;
4879                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
4880                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4881                                 EXT4_I(inode)->i_extra_isize;
4882                 physical += offset;
4883                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4884                 brelse(iloc.bh);
4885                 iomap_type = IOMAP_INLINE;
4886         } else if (EXT4_I(inode)->i_file_acl) { /* external block */
4887                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4888                 length = inode->i_sb->s_blocksize;
4889                 iomap_type = IOMAP_MAPPED;
4890         } else {
4891                 /* no in-inode or external block for xattr, so return -ENOENT */
4892                 error = -ENOENT;
4893                 goto out;
4894         }
4895
4896         iomap->addr = physical;
4897         iomap->offset = 0;
4898         iomap->length = length;
4899         iomap->type = iomap_type;
4900         iomap->flags = 0;
4901 out:
4902         return error;
4903 }
4904
4905 static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
4906                                   loff_t length, unsigned flags,
4907                                   struct iomap *iomap, struct iomap *srcmap)
4908 {
4909         int error;
4910
4911         error = ext4_iomap_xattr_fiemap(inode, iomap);
4912         if (error == 0 && (offset >= iomap->length))
4913                 error = -ENOENT;
4914         return error;
4915 }
4916
4917 static const struct iomap_ops ext4_iomap_xattr_ops = {
4918         .iomap_begin            = ext4_iomap_xattr_begin,
4919 };
4920
4921 static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
4922 {
4923         u64 maxbytes;
4924
4925         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4926                 maxbytes = inode->i_sb->s_maxbytes;
4927         else
4928                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
4929
4930         if (*len == 0)
4931                 return -EINVAL;
4932         if (start > maxbytes)
4933                 return -EFBIG;
4934
4935         /*
4936          * Shrink request scope to what the fs can actually handle.
4937          */
4938         if (*len > maxbytes || (maxbytes - *len) < start)
4939                 *len = maxbytes - start;
4940         return 0;
4941 }
4942
4943 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4944                 u64 start, u64 len)
4945 {
4946         int error = 0;
4947
4948         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4949                 error = ext4_ext_precache(inode);
4950                 if (error)
4951                         return error;
4952                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4953         }
4954
4955         /*
4956          * For bitmap files the maximum size limit could be smaller than
4957          * s_maxbytes, so check len here manually instead of just relying on the
4958          * generic check.
4959          */
4960         error = ext4_fiemap_check_ranges(inode, start, &len);
4961         if (error)
4962                 return error;
4963
4964         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4965                 fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
4966                 return iomap_fiemap(inode, fieinfo, start, len,
4967                                     &ext4_iomap_xattr_ops);
4968         }
4969
4970         return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
4971 }
4972
4973 int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
4974                       __u64 start, __u64 len)
4975 {
4976         ext4_lblk_t start_blk, len_blks;
4977         __u64 last_blk;
4978         int error = 0;
4979
4980         if (ext4_has_inline_data(inode)) {
4981                 int has_inline;
4982
4983                 down_read(&EXT4_I(inode)->xattr_sem);
4984                 has_inline = ext4_has_inline_data(inode);
4985                 up_read(&EXT4_I(inode)->xattr_sem);
4986                 if (has_inline)
4987                         return 0;
4988         }
4989
4990         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4991                 error = ext4_ext_precache(inode);
4992                 if (error)
4993                         return error;
4994                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4995         }
4996
4997         error = fiemap_prep(inode, fieinfo, start, &len, 0);
4998         if (error)
4999                 return error;
5000
5001         error = ext4_fiemap_check_ranges(inode, start, &len);
5002         if (error)
5003                 return error;
5004
5005         start_blk = start >> inode->i_sb->s_blocksize_bits;
5006         last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5007         if (last_blk >= EXT_MAX_BLOCKS)
5008                 last_blk = EXT_MAX_BLOCKS-1;
5009         len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5010
5011         /*
5012          * Walk the extent tree gathering extent information
5013          * and pushing extents back to the user.
5014          */
5015         return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
5016 }
5017
5018 /*
5019  * ext4_ext_shift_path_extents:
5020  * Shift the extents of a path structure lying between path[depth].p_ext
5021  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5022  * if it is right shift or left shift operation.
5023  */
5024 static int
5025 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5026                             struct inode *inode, handle_t *handle,
5027                             enum SHIFT_DIRECTION SHIFT)
5028 {
5029         int depth, err = 0;
5030         struct ext4_extent *ex_start, *ex_last;
5031         bool update = false;
5032         int credits, restart_credits;
5033         depth = path->p_depth;
5034
5035         while (depth >= 0) {
5036                 if (depth == path->p_depth) {
5037                         ex_start = path[depth].p_ext;
5038                         if (!ex_start)
5039                                 return -EFSCORRUPTED;
5040
5041                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5042                         /* leaf + sb + inode */
5043                         credits = 3;
5044                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
5045                                 update = true;
5046                                 /* extent tree + sb + inode */
5047                                 credits = depth + 2;
5048                         }
5049
5050                         restart_credits = ext4_writepage_trans_blocks(inode);
5051                         err = ext4_datasem_ensure_credits(handle, inode, credits,
5052                                         restart_credits, 0);
5053                         if (err) {
5054                                 if (err > 0)
5055                                         err = -EAGAIN;
5056                                 goto out;
5057                         }
5058
5059                         err = ext4_ext_get_access(handle, inode, path + depth);
5060                         if (err)
5061                                 goto out;
5062
5063                         while (ex_start <= ex_last) {
5064                                 if (SHIFT == SHIFT_LEFT) {
5065                                         le32_add_cpu(&ex_start->ee_block,
5066                                                 -shift);
5067                                         /* Try to merge to the left. */
5068                                         if ((ex_start >
5069                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5070                                             &&
5071                                             ext4_ext_try_to_merge_right(inode,
5072                                             path, ex_start - 1))
5073                                                 ex_last--;
5074                                         else
5075                                                 ex_start++;
5076                                 } else {
5077                                         le32_add_cpu(&ex_last->ee_block, shift);
5078                                         ext4_ext_try_to_merge_right(inode, path,
5079                                                 ex_last);
5080                                         ex_last--;
5081                                 }
5082                         }
5083                         err = ext4_ext_dirty(handle, inode, path + depth);
5084                         if (err)
5085                                 goto out;
5086
5087                         if (--depth < 0 || !update)
5088                                 break;
5089                 }
5090
5091                 /* Update index too */
5092                 err = ext4_ext_get_access(handle, inode, path + depth);
5093                 if (err)
5094                         goto out;
5095
5096                 if (SHIFT == SHIFT_LEFT)
5097                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5098                 else
5099                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5100                 err = ext4_ext_dirty(handle, inode, path + depth);
5101                 if (err)
5102                         goto out;
5103
5104                 /* we are done if current index is not a starting index */
5105                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5106                         break;
5107
5108                 depth--;
5109         }
5110
5111 out:
5112         return err;
5113 }
5114
5115 /*
5116  * ext4_ext_shift_extents:
5117  * All the extents which lies in the range from @start to the last allocated
5118  * block for the @inode are shifted either towards left or right (depending
5119  * upon @SHIFT) by @shift blocks.
5120  * On success, 0 is returned, error otherwise.
5121  */
5122 static int
5123 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5124                        ext4_lblk_t start, ext4_lblk_t shift,
5125                        enum SHIFT_DIRECTION SHIFT)
5126 {
5127         struct ext4_ext_path *path;
5128         int ret = 0, depth;
5129         struct ext4_extent *extent;
5130         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5131         ext4_lblk_t tmp = EXT_MAX_BLOCKS;
5132
5133         /* Let path point to the last extent */
5134         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5135                                 EXT4_EX_NOCACHE);
5136         if (IS_ERR(path))
5137                 return PTR_ERR(path);
5138
5139         depth = path->p_depth;
5140         extent = path[depth].p_ext;
5141         if (!extent)
5142                 goto out;
5143
5144         stop = le32_to_cpu(extent->ee_block);
5145
5146        /*
5147         * For left shifts, make sure the hole on the left is big enough to
5148         * accommodate the shift.  For right shifts, make sure the last extent
5149         * won't be shifted beyond EXT_MAX_BLOCKS.
5150         */
5151         if (SHIFT == SHIFT_LEFT) {
5152                 path = ext4_find_extent(inode, start - 1, &path,
5153                                         EXT4_EX_NOCACHE);
5154                 if (IS_ERR(path))
5155                         return PTR_ERR(path);
5156                 depth = path->p_depth;
5157                 extent =  path[depth].p_ext;
5158                 if (extent) {
5159                         ex_start = le32_to_cpu(extent->ee_block);
5160                         ex_end = le32_to_cpu(extent->ee_block) +
5161                                 ext4_ext_get_actual_len(extent);
5162                 } else {
5163                         ex_start = 0;
5164                         ex_end = 0;
5165                 }
5166
5167                 if ((start == ex_start && shift > ex_start) ||
5168                     (shift > start - ex_end)) {
5169                         ret = -EINVAL;
5170                         goto out;
5171                 }
5172         } else {
5173                 if (shift > EXT_MAX_BLOCKS -
5174                     (stop + ext4_ext_get_actual_len(extent))) {
5175                         ret = -EINVAL;
5176                         goto out;
5177                 }
5178         }
5179
5180         /*
5181          * In case of left shift, iterator points to start and it is increased
5182          * till we reach stop. In case of right shift, iterator points to stop
5183          * and it is decreased till we reach start.
5184          */
5185 again:
5186         if (SHIFT == SHIFT_LEFT)
5187                 iterator = &start;
5188         else
5189                 iterator = &stop;
5190
5191         if (tmp != EXT_MAX_BLOCKS)
5192                 *iterator = tmp;
5193
5194         /*
5195          * Its safe to start updating extents.  Start and stop are unsigned, so
5196          * in case of right shift if extent with 0 block is reached, iterator
5197          * becomes NULL to indicate the end of the loop.
5198          */
5199         while (iterator && start <= stop) {
5200                 path = ext4_find_extent(inode, *iterator, &path,
5201                                         EXT4_EX_NOCACHE);
5202                 if (IS_ERR(path))
5203                         return PTR_ERR(path);
5204                 depth = path->p_depth;
5205                 extent = path[depth].p_ext;
5206                 if (!extent) {
5207                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5208                                          (unsigned long) *iterator);
5209                         return -EFSCORRUPTED;
5210                 }
5211                 if (SHIFT == SHIFT_LEFT && *iterator >
5212                     le32_to_cpu(extent->ee_block)) {
5213                         /* Hole, move to the next extent */
5214                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5215                                 path[depth].p_ext++;
5216                         } else {
5217                                 *iterator = ext4_ext_next_allocated_block(path);
5218                                 continue;
5219                         }
5220                 }
5221
5222                 tmp = *iterator;
5223                 if (SHIFT == SHIFT_LEFT) {
5224                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5225                         *iterator = le32_to_cpu(extent->ee_block) +
5226                                         ext4_ext_get_actual_len(extent);
5227                 } else {
5228                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5229                         if (le32_to_cpu(extent->ee_block) > 0)
5230                                 *iterator = le32_to_cpu(extent->ee_block) - 1;
5231                         else
5232                                 /* Beginning is reached, end of the loop */
5233                                 iterator = NULL;
5234                         /* Update path extent in case we need to stop */
5235                         while (le32_to_cpu(extent->ee_block) < start)
5236                                 extent++;
5237                         path[depth].p_ext = extent;
5238                 }
5239                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5240                                 handle, SHIFT);
5241                 /* iterator can be NULL which means we should break */
5242                 if (ret == -EAGAIN)
5243                         goto again;
5244                 if (ret)
5245                         break;
5246         }
5247 out:
5248         ext4_ext_drop_refs(path);
5249         kfree(path);
5250         return ret;
5251 }
5252
5253 /*
5254  * ext4_collapse_range:
5255  * This implements the fallocate's collapse range functionality for ext4
5256  * Returns: 0 and non-zero on error.
5257  */
5258 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)
5259 {
5260         struct inode *inode = file_inode(file);
5261         struct super_block *sb = inode->i_sb;
5262         struct address_space *mapping = inode->i_mapping;
5263         ext4_lblk_t punch_start, punch_stop;
5264         handle_t *handle;
5265         unsigned int credits;
5266         loff_t new_size, ioffset;
5267         int ret;
5268
5269         /*
5270          * We need to test this early because xfstests assumes that a
5271          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5272          * system does not support collapse range.
5273          */
5274         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5275                 return -EOPNOTSUPP;
5276
5277         /* Collapse range works only on fs cluster size aligned regions. */
5278         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5279                 return -EINVAL;
5280
5281         trace_ext4_collapse_range(inode, offset, len);
5282
5283         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5284         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5285
5286         /* Call ext4_force_commit to flush all data in case of data=journal. */
5287         if (ext4_should_journal_data(inode)) {
5288                 ret = ext4_force_commit(inode->i_sb);
5289                 if (ret)
5290                         return ret;
5291         }
5292
5293         inode_lock(inode);
5294         /*
5295          * There is no need to overlap collapse range with EOF, in which case
5296          * it is effectively a truncate operation
5297          */
5298         if (offset + len >= inode->i_size) {
5299                 ret = -EINVAL;
5300                 goto out_mutex;
5301         }
5302
5303         /* Currently just for extent based files */
5304         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5305                 ret = -EOPNOTSUPP;
5306                 goto out_mutex;
5307         }
5308
5309         /* Wait for existing dio to complete */
5310         inode_dio_wait(inode);
5311
5312         ret = file_modified(file);
5313         if (ret)
5314                 goto out_mutex;
5315
5316         /*
5317          * Prevent page faults from reinstantiating pages we have released from
5318          * page cache.
5319          */
5320         filemap_invalidate_lock(mapping);
5321
5322         ret = ext4_break_layouts(inode);
5323         if (ret)
5324                 goto out_mmap;
5325
5326         /*
5327          * Need to round down offset to be aligned with page size boundary
5328          * for page size > block size.
5329          */
5330         ioffset = round_down(offset, PAGE_SIZE);
5331         /*
5332          * Write tail of the last page before removed range since it will get
5333          * removed from the page cache below.
5334          */
5335         ret = filemap_write_and_wait_range(mapping, ioffset, offset);
5336         if (ret)
5337                 goto out_mmap;
5338         /*
5339          * Write data that will be shifted to preserve them when discarding
5340          * page cache below. We are also protected from pages becoming dirty
5341          * by i_rwsem and invalidate_lock.
5342          */
5343         ret = filemap_write_and_wait_range(mapping, offset + len,
5344                                            LLONG_MAX);
5345         if (ret)
5346                 goto out_mmap;
5347         truncate_pagecache(inode, ioffset);
5348
5349         credits = ext4_writepage_trans_blocks(inode);
5350         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5351         if (IS_ERR(handle)) {
5352                 ret = PTR_ERR(handle);
5353                 goto out_mmap;
5354         }
5355         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5356
5357         down_write(&EXT4_I(inode)->i_data_sem);
5358         ext4_discard_preallocations(inode, 0);
5359
5360         ret = ext4_es_remove_extent(inode, punch_start,
5361                                     EXT_MAX_BLOCKS - punch_start);
5362         if (ret) {
5363                 up_write(&EXT4_I(inode)->i_data_sem);
5364                 goto out_stop;
5365         }
5366
5367         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5368         if (ret) {
5369                 up_write(&EXT4_I(inode)->i_data_sem);
5370                 goto out_stop;
5371         }
5372         ext4_discard_preallocations(inode, 0);
5373
5374         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5375                                      punch_stop - punch_start, SHIFT_LEFT);
5376         if (ret) {
5377                 up_write(&EXT4_I(inode)->i_data_sem);
5378                 goto out_stop;
5379         }
5380
5381         new_size = inode->i_size - len;
5382         i_size_write(inode, new_size);
5383         EXT4_I(inode)->i_disksize = new_size;
5384
5385         up_write(&EXT4_I(inode)->i_data_sem);
5386         if (IS_SYNC(inode))
5387                 ext4_handle_sync(handle);
5388         inode->i_mtime = inode->i_ctime = current_time(inode);
5389         ret = ext4_mark_inode_dirty(handle, inode);
5390         ext4_update_inode_fsync_trans(handle, inode, 1);
5391
5392 out_stop:
5393         ext4_journal_stop(handle);
5394 out_mmap:
5395         filemap_invalidate_unlock(mapping);
5396 out_mutex:
5397         inode_unlock(inode);
5398         return ret;
5399 }
5400
5401 /*
5402  * ext4_insert_range:
5403  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5404  * The data blocks starting from @offset to the EOF are shifted by @len
5405  * towards right to create a hole in the @inode. Inode size is increased
5406  * by len bytes.
5407  * Returns 0 on success, error otherwise.
5408  */
5409 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
5410 {
5411         struct inode *inode = file_inode(file);
5412         struct super_block *sb = inode->i_sb;
5413         struct address_space *mapping = inode->i_mapping;
5414         handle_t *handle;
5415         struct ext4_ext_path *path;
5416         struct ext4_extent *extent;
5417         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5418         unsigned int credits, ee_len;
5419         int ret = 0, depth, split_flag = 0;
5420         loff_t ioffset;
5421
5422         /*
5423          * We need to test this early because xfstests assumes that an
5424          * insert range of (0, 1) will return EOPNOTSUPP if the file
5425          * system does not support insert range.
5426          */
5427         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5428                 return -EOPNOTSUPP;
5429
5430         /* Insert range works only on fs cluster size aligned regions. */
5431         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5432                 return -EINVAL;
5433
5434         trace_ext4_insert_range(inode, offset, len);
5435
5436         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5437         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5438
5439         /* Call ext4_force_commit to flush all data in case of data=journal */
5440         if (ext4_should_journal_data(inode)) {
5441                 ret = ext4_force_commit(inode->i_sb);
5442                 if (ret)
5443                         return ret;
5444         }
5445
5446         inode_lock(inode);
5447         /* Currently just for extent based files */
5448         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5449                 ret = -EOPNOTSUPP;
5450                 goto out_mutex;
5451         }
5452
5453         /* Check whether the maximum file size would be exceeded */
5454         if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5455                 ret = -EFBIG;
5456                 goto out_mutex;
5457         }
5458
5459         /* Offset must be less than i_size */
5460         if (offset >= inode->i_size) {
5461                 ret = -EINVAL;
5462                 goto out_mutex;
5463         }
5464
5465         /* Wait for existing dio to complete */
5466         inode_dio_wait(inode);
5467
5468         ret = file_modified(file);
5469         if (ret)
5470                 goto out_mutex;
5471
5472         /*
5473          * Prevent page faults from reinstantiating pages we have released from
5474          * page cache.
5475          */
5476         filemap_invalidate_lock(mapping);
5477
5478         ret = ext4_break_layouts(inode);
5479         if (ret)
5480                 goto out_mmap;
5481
5482         /*
5483          * Need to round down to align start offset to page size boundary
5484          * for page size > block size.
5485          */
5486         ioffset = round_down(offset, PAGE_SIZE);
5487         /* Write out all dirty pages */
5488         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5489                         LLONG_MAX);
5490         if (ret)
5491                 goto out_mmap;
5492         truncate_pagecache(inode, ioffset);
5493
5494         credits = ext4_writepage_trans_blocks(inode);
5495         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5496         if (IS_ERR(handle)) {
5497                 ret = PTR_ERR(handle);
5498                 goto out_mmap;
5499         }
5500         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5501
5502         /* Expand file to avoid data loss if there is error while shifting */
5503         inode->i_size += len;
5504         EXT4_I(inode)->i_disksize += len;
5505         inode->i_mtime = inode->i_ctime = current_time(inode);
5506         ret = ext4_mark_inode_dirty(handle, inode);
5507         if (ret)
5508                 goto out_stop;
5509
5510         down_write(&EXT4_I(inode)->i_data_sem);
5511         ext4_discard_preallocations(inode, 0);
5512
5513         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5514         if (IS_ERR(path)) {
5515                 up_write(&EXT4_I(inode)->i_data_sem);
5516                 goto out_stop;
5517         }
5518
5519         depth = ext_depth(inode);
5520         extent = path[depth].p_ext;
5521         if (extent) {
5522                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5523                 ee_len = ext4_ext_get_actual_len(extent);
5524
5525                 /*
5526                  * If offset_lblk is not the starting block of extent, split
5527                  * the extent @offset_lblk
5528                  */
5529                 if ((offset_lblk > ee_start_lblk) &&
5530                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5531                         if (ext4_ext_is_unwritten(extent))
5532                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5533                                         EXT4_EXT_MARK_UNWRIT2;
5534                         ret = ext4_split_extent_at(handle, inode, &path,
5535                                         offset_lblk, split_flag,
5536                                         EXT4_EX_NOCACHE |
5537                                         EXT4_GET_BLOCKS_PRE_IO |
5538                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5539                 }
5540
5541                 ext4_ext_drop_refs(path);
5542                 kfree(path);
5543                 if (ret < 0) {
5544                         up_write(&EXT4_I(inode)->i_data_sem);
5545                         goto out_stop;
5546                 }
5547         } else {
5548                 ext4_ext_drop_refs(path);
5549                 kfree(path);
5550         }
5551
5552         ret = ext4_es_remove_extent(inode, offset_lblk,
5553                         EXT_MAX_BLOCKS - offset_lblk);
5554         if (ret) {
5555                 up_write(&EXT4_I(inode)->i_data_sem);
5556                 goto out_stop;
5557         }
5558
5559         /*
5560          * if offset_lblk lies in a hole which is at start of file, use
5561          * ee_start_lblk to shift extents
5562          */
5563         ret = ext4_ext_shift_extents(inode, handle,
5564                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5565                 len_lblk, SHIFT_RIGHT);
5566
5567         up_write(&EXT4_I(inode)->i_data_sem);
5568         if (IS_SYNC(inode))
5569                 ext4_handle_sync(handle);
5570         if (ret >= 0)
5571                 ext4_update_inode_fsync_trans(handle, inode, 1);
5572
5573 out_stop:
5574         ext4_journal_stop(handle);
5575 out_mmap:
5576         filemap_invalidate_unlock(mapping);
5577 out_mutex:
5578         inode_unlock(inode);
5579         return ret;
5580 }
5581
5582 /**
5583  * ext4_swap_extents() - Swap extents between two inodes
5584  * @handle: handle for this transaction
5585  * @inode1:     First inode
5586  * @inode2:     Second inode
5587  * @lblk1:      Start block for first inode
5588  * @lblk2:      Start block for second inode
5589  * @count:      Number of blocks to swap
5590  * @unwritten: Mark second inode's extents as unwritten after swap
5591  * @erp:        Pointer to save error value
5592  *
5593  * This helper routine does exactly what is promise "swap extents". All other
5594  * stuff such as page-cache locking consistency, bh mapping consistency or
5595  * extent's data copying must be performed by caller.
5596  * Locking:
5597  *              i_rwsem is held for both inodes
5598  *              i_data_sem is locked for write for both inodes
5599  * Assumptions:
5600  *              All pages from requested range are locked for both inodes
5601  */
5602 int
5603 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5604                   struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5605                   ext4_lblk_t count, int unwritten, int *erp)
5606 {
5607         struct ext4_ext_path *path1 = NULL;
5608         struct ext4_ext_path *path2 = NULL;
5609         int replaced_count = 0;
5610
5611         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5612         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5613         BUG_ON(!inode_is_locked(inode1));
5614         BUG_ON(!inode_is_locked(inode2));
5615
5616         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5617         if (unlikely(*erp))
5618                 return 0;
5619         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5620         if (unlikely(*erp))
5621                 return 0;
5622
5623         while (count) {
5624                 struct ext4_extent *ex1, *ex2, tmp_ex;
5625                 ext4_lblk_t e1_blk, e2_blk;
5626                 int e1_len, e2_len, len;
5627                 int split = 0;
5628
5629                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5630                 if (IS_ERR(path1)) {
5631                         *erp = PTR_ERR(path1);
5632                         path1 = NULL;
5633                 finish:
5634                         count = 0;
5635                         goto repeat;
5636                 }
5637                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5638                 if (IS_ERR(path2)) {
5639                         *erp = PTR_ERR(path2);
5640                         path2 = NULL;
5641                         goto finish;
5642                 }
5643                 ex1 = path1[path1->p_depth].p_ext;
5644                 ex2 = path2[path2->p_depth].p_ext;
5645                 /* Do we have something to swap ? */
5646                 if (unlikely(!ex2 || !ex1))
5647                         goto finish;
5648
5649                 e1_blk = le32_to_cpu(ex1->ee_block);
5650                 e2_blk = le32_to_cpu(ex2->ee_block);
5651                 e1_len = ext4_ext_get_actual_len(ex1);
5652                 e2_len = ext4_ext_get_actual_len(ex2);
5653
5654                 /* Hole handling */
5655                 if (!in_range(lblk1, e1_blk, e1_len) ||
5656                     !in_range(lblk2, e2_blk, e2_len)) {
5657                         ext4_lblk_t next1, next2;
5658
5659                         /* if hole after extent, then go to next extent */
5660                         next1 = ext4_ext_next_allocated_block(path1);
5661                         next2 = ext4_ext_next_allocated_block(path2);
5662                         /* If hole before extent, then shift to that extent */
5663                         if (e1_blk > lblk1)
5664                                 next1 = e1_blk;
5665                         if (e2_blk > lblk2)
5666                                 next2 = e2_blk;
5667                         /* Do we have something to swap */
5668                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5669                                 goto finish;
5670                         /* Move to the rightest boundary */
5671                         len = next1 - lblk1;
5672                         if (len < next2 - lblk2)
5673                                 len = next2 - lblk2;
5674                         if (len > count)
5675                                 len = count;
5676                         lblk1 += len;
5677                         lblk2 += len;
5678                         count -= len;
5679                         goto repeat;
5680                 }
5681
5682                 /* Prepare left boundary */
5683                 if (e1_blk < lblk1) {
5684                         split = 1;
5685                         *erp = ext4_force_split_extent_at(handle, inode1,
5686                                                 &path1, lblk1, 0);
5687                         if (unlikely(*erp))
5688                                 goto finish;
5689                 }
5690                 if (e2_blk < lblk2) {
5691                         split = 1;
5692                         *erp = ext4_force_split_extent_at(handle, inode2,
5693                                                 &path2,  lblk2, 0);
5694                         if (unlikely(*erp))
5695                                 goto finish;
5696                 }
5697                 /* ext4_split_extent_at() may result in leaf extent split,
5698                  * path must to be revalidated. */
5699                 if (split)
5700                         goto repeat;
5701
5702                 /* Prepare right boundary */
5703                 len = count;
5704                 if (len > e1_blk + e1_len - lblk1)
5705                         len = e1_blk + e1_len - lblk1;
5706                 if (len > e2_blk + e2_len - lblk2)
5707                         len = e2_blk + e2_len - lblk2;
5708
5709                 if (len != e1_len) {
5710                         split = 1;
5711                         *erp = ext4_force_split_extent_at(handle, inode1,
5712                                                 &path1, lblk1 + len, 0);
5713                         if (unlikely(*erp))
5714                                 goto finish;
5715                 }
5716                 if (len != e2_len) {
5717                         split = 1;
5718                         *erp = ext4_force_split_extent_at(handle, inode2,
5719                                                 &path2, lblk2 + len, 0);
5720                         if (*erp)
5721                                 goto finish;
5722                 }
5723                 /* ext4_split_extent_at() may result in leaf extent split,
5724                  * path must to be revalidated. */
5725                 if (split)
5726                         goto repeat;
5727
5728                 BUG_ON(e2_len != e1_len);
5729                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5730                 if (unlikely(*erp))
5731                         goto finish;
5732                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5733                 if (unlikely(*erp))
5734                         goto finish;
5735
5736                 /* Both extents are fully inside boundaries. Swap it now */
5737                 tmp_ex = *ex1;
5738                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5739                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5740                 ex1->ee_len = cpu_to_le16(e2_len);
5741                 ex2->ee_len = cpu_to_le16(e1_len);
5742                 if (unwritten)
5743                         ext4_ext_mark_unwritten(ex2);
5744                 if (ext4_ext_is_unwritten(&tmp_ex))
5745                         ext4_ext_mark_unwritten(ex1);
5746
5747                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5748                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5749                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5750                                       path2->p_depth);
5751                 if (unlikely(*erp))
5752                         goto finish;
5753                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5754                                       path1->p_depth);
5755                 /*
5756                  * Looks scarry ah..? second inode already points to new blocks,
5757                  * and it was successfully dirtied. But luckily error may happen
5758                  * only due to journal error, so full transaction will be
5759                  * aborted anyway.
5760                  */
5761                 if (unlikely(*erp))
5762                         goto finish;
5763                 lblk1 += len;
5764                 lblk2 += len;
5765                 replaced_count += len;
5766                 count -= len;
5767
5768         repeat:
5769                 ext4_ext_drop_refs(path1);
5770                 kfree(path1);
5771                 ext4_ext_drop_refs(path2);
5772                 kfree(path2);
5773                 path1 = path2 = NULL;
5774         }
5775         return replaced_count;
5776 }
5777
5778 /*
5779  * ext4_clu_mapped - determine whether any block in a logical cluster has
5780  *                   been mapped to a physical cluster
5781  *
5782  * @inode - file containing the logical cluster
5783  * @lclu - logical cluster of interest
5784  *
5785  * Returns 1 if any block in the logical cluster is mapped, signifying
5786  * that a physical cluster has been allocated for it.  Otherwise,
5787  * returns 0.  Can also return negative error codes.  Derived from
5788  * ext4_ext_map_blocks().
5789  */
5790 int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5791 {
5792         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5793         struct ext4_ext_path *path;
5794         int depth, mapped = 0, err = 0;
5795         struct ext4_extent *extent;
5796         ext4_lblk_t first_lblk, first_lclu, last_lclu;
5797
5798         /* search for the extent closest to the first block in the cluster */
5799         path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5800         if (IS_ERR(path)) {
5801                 err = PTR_ERR(path);
5802                 path = NULL;
5803                 goto out;
5804         }
5805
5806         depth = ext_depth(inode);
5807
5808         /*
5809          * A consistent leaf must not be empty.  This situation is possible,
5810          * though, _during_ tree modification, and it's why an assert can't
5811          * be put in ext4_find_extent().
5812          */
5813         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5814                 EXT4_ERROR_INODE(inode,
5815                     "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5816                                  (unsigned long) EXT4_C2B(sbi, lclu),
5817                                  depth, path[depth].p_block);
5818                 err = -EFSCORRUPTED;
5819                 goto out;
5820         }
5821
5822         extent = path[depth].p_ext;
5823
5824         /* can't be mapped if the extent tree is empty */
5825         if (extent == NULL)
5826                 goto out;
5827
5828         first_lblk = le32_to_cpu(extent->ee_block);
5829         first_lclu = EXT4_B2C(sbi, first_lblk);
5830
5831         /*
5832          * Three possible outcomes at this point - found extent spanning
5833          * the target cluster, to the left of the target cluster, or to the
5834          * right of the target cluster.  The first two cases are handled here.
5835          * The last case indicates the target cluster is not mapped.
5836          */
5837         if (lclu >= first_lclu) {
5838                 last_lclu = EXT4_B2C(sbi, first_lblk +
5839                                      ext4_ext_get_actual_len(extent) - 1);
5840                 if (lclu <= last_lclu) {
5841                         mapped = 1;
5842                 } else {
5843                         first_lblk = ext4_ext_next_allocated_block(path);
5844                         first_lclu = EXT4_B2C(sbi, first_lblk);
5845                         if (lclu == first_lclu)
5846                                 mapped = 1;
5847                 }
5848         }
5849
5850 out:
5851         ext4_ext_drop_refs(path);
5852         kfree(path);
5853
5854         return err ? err : mapped;
5855 }
5856
5857 /*
5858  * Updates physical block address and unwritten status of extent
5859  * starting at lblk start and of len. If such an extent doesn't exist,
5860  * this function splits the extent tree appropriately to create an
5861  * extent like this.  This function is called in the fast commit
5862  * replay path.  Returns 0 on success and error on failure.
5863  */
5864 int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
5865                               int len, int unwritten, ext4_fsblk_t pblk)
5866 {
5867         struct ext4_ext_path *path = NULL, *ppath;
5868         struct ext4_extent *ex;
5869         int ret;
5870
5871         path = ext4_find_extent(inode, start, NULL, 0);
5872         if (IS_ERR(path))
5873                 return PTR_ERR(path);
5874         ex = path[path->p_depth].p_ext;
5875         if (!ex) {
5876                 ret = -EFSCORRUPTED;
5877                 goto out;
5878         }
5879
5880         if (le32_to_cpu(ex->ee_block) != start ||
5881                 ext4_ext_get_actual_len(ex) != len) {
5882                 /* We need to split this extent to match our extent first */
5883                 ppath = path;
5884                 down_write(&EXT4_I(inode)->i_data_sem);
5885                 ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
5886                 up_write(&EXT4_I(inode)->i_data_sem);
5887                 if (ret)
5888                         goto out;
5889                 kfree(path);
5890                 path = ext4_find_extent(inode, start, NULL, 0);
5891                 if (IS_ERR(path))
5892                         return -1;
5893                 ppath = path;
5894                 ex = path[path->p_depth].p_ext;
5895                 WARN_ON(le32_to_cpu(ex->ee_block) != start);
5896                 if (ext4_ext_get_actual_len(ex) != len) {
5897                         down_write(&EXT4_I(inode)->i_data_sem);
5898                         ret = ext4_force_split_extent_at(NULL, inode, &ppath,
5899                                                          start + len, 1);
5900                         up_write(&EXT4_I(inode)->i_data_sem);
5901                         if (ret)
5902                                 goto out;
5903                         kfree(path);
5904                         path = ext4_find_extent(inode, start, NULL, 0);
5905                         if (IS_ERR(path))
5906                                 return -EINVAL;
5907                         ex = path[path->p_depth].p_ext;
5908                 }
5909         }
5910         if (unwritten)
5911                 ext4_ext_mark_unwritten(ex);
5912         else
5913                 ext4_ext_mark_initialized(ex);
5914         ext4_ext_store_pblock(ex, pblk);
5915         down_write(&EXT4_I(inode)->i_data_sem);
5916         ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5917         up_write(&EXT4_I(inode)->i_data_sem);
5918 out:
5919         ext4_ext_drop_refs(path);
5920         kfree(path);
5921         ext4_mark_inode_dirty(NULL, inode);
5922         return ret;
5923 }
5924
5925 /* Try to shrink the extent tree */
5926 void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
5927 {
5928         struct ext4_ext_path *path = NULL;
5929         struct ext4_extent *ex;
5930         ext4_lblk_t old_cur, cur = 0;
5931
5932         while (cur < end) {
5933                 path = ext4_find_extent(inode, cur, NULL, 0);
5934                 if (IS_ERR(path))
5935                         return;
5936                 ex = path[path->p_depth].p_ext;
5937                 if (!ex) {
5938                         ext4_ext_drop_refs(path);
5939                         kfree(path);
5940                         ext4_mark_inode_dirty(NULL, inode);
5941                         return;
5942                 }
5943                 old_cur = cur;
5944                 cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5945                 if (cur <= old_cur)
5946                         cur = old_cur + 1;
5947                 ext4_ext_try_to_merge(NULL, inode, path, ex);
5948                 down_write(&EXT4_I(inode)->i_data_sem);
5949                 ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5950                 up_write(&EXT4_I(inode)->i_data_sem);
5951                 ext4_mark_inode_dirty(NULL, inode);
5952                 ext4_ext_drop_refs(path);
5953                 kfree(path);
5954         }
5955 }
5956
5957 /* Check if *cur is a hole and if it is, skip it */
5958 static int skip_hole(struct inode *inode, ext4_lblk_t *cur)
5959 {
5960         int ret;
5961         struct ext4_map_blocks map;
5962
5963         map.m_lblk = *cur;
5964         map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
5965
5966         ret = ext4_map_blocks(NULL, inode, &map, 0);
5967         if (ret < 0)
5968                 return ret;
5969         if (ret != 0)
5970                 return 0;
5971         *cur = *cur + map.m_len;
5972         return 0;
5973 }
5974
5975 /* Count number of blocks used by this inode and update i_blocks */
5976 int ext4_ext_replay_set_iblocks(struct inode *inode)
5977 {
5978         struct ext4_ext_path *path = NULL, *path2 = NULL;
5979         struct ext4_extent *ex;
5980         ext4_lblk_t cur = 0, end;
5981         int numblks = 0, i, ret = 0;
5982         ext4_fsblk_t cmp1, cmp2;
5983         struct ext4_map_blocks map;
5984
5985         /* Determin the size of the file first */
5986         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5987                                         EXT4_EX_NOCACHE);
5988         if (IS_ERR(path))
5989                 return PTR_ERR(path);
5990         ex = path[path->p_depth].p_ext;
5991         if (!ex) {
5992                 ext4_ext_drop_refs(path);
5993                 kfree(path);
5994                 goto out;
5995         }
5996         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5997         ext4_ext_drop_refs(path);
5998         kfree(path);
5999
6000         /* Count the number of data blocks */
6001         cur = 0;
6002         while (cur < end) {
6003                 map.m_lblk = cur;
6004                 map.m_len = end - cur;
6005                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6006                 if (ret < 0)
6007                         break;
6008                 if (ret > 0)
6009                         numblks += ret;
6010                 cur = cur + map.m_len;
6011         }
6012
6013         /*
6014          * Count the number of extent tree blocks. We do it by looking up
6015          * two successive extents and determining the difference between
6016          * their paths. When path is different for 2 successive extents
6017          * we compare the blocks in the path at each level and increment
6018          * iblocks by total number of differences found.
6019          */
6020         cur = 0;
6021         ret = skip_hole(inode, &cur);
6022         if (ret < 0)
6023                 goto out;
6024         path = ext4_find_extent(inode, cur, NULL, 0);
6025         if (IS_ERR(path))
6026                 goto out;
6027         numblks += path->p_depth;
6028         ext4_ext_drop_refs(path);
6029         kfree(path);
6030         while (cur < end) {
6031                 path = ext4_find_extent(inode, cur, NULL, 0);
6032                 if (IS_ERR(path))
6033                         break;
6034                 ex = path[path->p_depth].p_ext;
6035                 if (!ex) {
6036                         ext4_ext_drop_refs(path);
6037                         kfree(path);
6038                         return 0;
6039                 }
6040                 cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
6041                                         ext4_ext_get_actual_len(ex));
6042                 ret = skip_hole(inode, &cur);
6043                 if (ret < 0) {
6044                         ext4_ext_drop_refs(path);
6045                         kfree(path);
6046                         break;
6047                 }
6048                 path2 = ext4_find_extent(inode, cur, NULL, 0);
6049                 if (IS_ERR(path2)) {
6050                         ext4_ext_drop_refs(path);
6051                         kfree(path);
6052                         break;
6053                 }
6054                 for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
6055                         cmp1 = cmp2 = 0;
6056                         if (i <= path->p_depth)
6057                                 cmp1 = path[i].p_bh ?
6058                                         path[i].p_bh->b_blocknr : 0;
6059                         if (i <= path2->p_depth)
6060                                 cmp2 = path2[i].p_bh ?
6061                                         path2[i].p_bh->b_blocknr : 0;
6062                         if (cmp1 != cmp2 && cmp2 != 0)
6063                                 numblks++;
6064                 }
6065                 ext4_ext_drop_refs(path);
6066                 ext4_ext_drop_refs(path2);
6067                 kfree(path);
6068                 kfree(path2);
6069         }
6070
6071 out:
6072         inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
6073         ext4_mark_inode_dirty(NULL, inode);
6074         return 0;
6075 }
6076
6077 int ext4_ext_clear_bb(struct inode *inode)
6078 {
6079         struct ext4_ext_path *path = NULL;
6080         struct ext4_extent *ex;
6081         ext4_lblk_t cur = 0, end;
6082         int j, ret = 0;
6083         struct ext4_map_blocks map;
6084
6085         if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA))
6086                 return 0;
6087
6088         /* Determin the size of the file first */
6089         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6090                                         EXT4_EX_NOCACHE);
6091         if (IS_ERR(path))
6092                 return PTR_ERR(path);
6093         ex = path[path->p_depth].p_ext;
6094         if (!ex) {
6095                 ext4_ext_drop_refs(path);
6096                 kfree(path);
6097                 return 0;
6098         }
6099         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6100         ext4_ext_drop_refs(path);
6101         kfree(path);
6102
6103         cur = 0;
6104         while (cur < end) {
6105                 map.m_lblk = cur;
6106                 map.m_len = end - cur;
6107                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6108                 if (ret < 0)
6109                         break;
6110                 if (ret > 0) {
6111                         path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
6112                         if (!IS_ERR_OR_NULL(path)) {
6113                                 for (j = 0; j < path->p_depth; j++) {
6114
6115                                         ext4_mb_mark_bb(inode->i_sb,
6116                                                         path[j].p_block, 1, 0);
6117                                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6118                                                         0, path[j].p_block, 1, 1);
6119                                 }
6120                                 ext4_ext_drop_refs(path);
6121                                 kfree(path);
6122                         }
6123                         ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
6124                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6125                                         map.m_lblk, map.m_pblk, map.m_len, 1);
6126                 }
6127                 cur = cur + map.m_len;
6128         }
6129
6130         return 0;
6131 }