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 static void ext4_ext_drop_refs(struct ext4_ext_path *path)
 110 {
 111         int depth, i;
 112
 113         if (!path)
 114                 return;
 115         depth = path->p_depth;
 116         for (i = 0; i <= depth; i++, path++) {
 117                 brelse(path->p_bh);
 118                 path->p_bh = NULL;
 119         }
 120 }
 121
 122 void ext4_free_ext_path(struct ext4_ext_path *path)
 123 {
 124         ext4_ext_drop_refs(path);
 125         kfree(path);
 126 }
 127
 128 /*
 129  * Make sure 'handle' has at least 'check_cred' credits. If not, restart
 130  * transaction with 'restart_cred' credits. The function drops i_data_sem
 131  * when restarting transaction and gets it after transaction is restarted.
 132  *
 133  * The function returns 0 on success, 1 if transaction had to be restarted,
 134  * and < 0 in case of fatal error.
 135  */
 136 int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,
 137                                 int check_cred, int restart_cred,
 138                                 int revoke_cred)
 139 {
 140         int ret;
 141         int dropped = 0;
 142
 143         ret = ext4_journal_ensure_credits_fn(handle, check_cred, restart_cred,
 144                 revoke_cred, ext4_ext_trunc_restart_fn(inode, &dropped));
 145         if (dropped)
 146                 down_write(&EXT4_I(inode)->i_data_sem);
 147         return ret;
 148 }
 149
 150 /*
 151  * could return:
 152  *  - EROFS
 153  *  - ENOMEM
 154  */
 155 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 156                                 struct ext4_ext_path *path)
 157 {
 158         int err = 0;
 159
 160         if (path->p_bh) {
 161                 /* path points to block */
 162                 BUFFER_TRACE(path->p_bh, "get_write_access");
 163                 err = ext4_journal_get_write_access(handle, inode->i_sb,
 164                                                     path->p_bh, EXT4_JTR_NONE);
 165                 /*
 166                  * The extent buffer's verified bit will be set again in
 167                  * __ext4_ext_dirty(). We could leave an inconsistent
 168                  * buffer if the extents updating procudure break off du
 169                  * to some error happens, force to check it again.
 170                  */
 171                 if (!err)
 172                         clear_buffer_verified(path->p_bh);
 173         }
 174         /* path points to leaf/index in inode body */
 175         /* we use in-core data, no need to protect them */
 176         return err;
 177 }
 178
 179 /*
 180  * could return:
 181  *  - EROFS
 182  *  - ENOMEM
 183  *  - EIO
 184  */
 185 static int __ext4_ext_dirty(const char *where, unsigned int line,
 186                             handle_t *handle, struct inode *inode,
 187                             struct ext4_ext_path *path)
 188 {
 189         int err;
 190
 191         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 192         if (path->p_bh) {
 193                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 194                 /* path points to block */
 195                 err = __ext4_handle_dirty_metadata(where, line, handle,
 196                                                    inode, path->p_bh);
 197                 /* Extents updating done, re-set verified flag */
 198                 if (!err)
 199                         set_buffer_verified(path->p_bh);
 200         } else {
 201                 /* path points to leaf/index in inode body */
 202                 err = ext4_mark_inode_dirty(handle, inode);
 203         }
 204         return err;
 205 }
 206
 207 #define ext4_ext_dirty(handle, inode, path) \
 208                 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
 209
 210 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 211                               struct ext4_ext_path *path,
 212                               ext4_lblk_t block)
 213 {
 214         if (path) {
 215                 int depth = path->p_depth;
 216                 struct ext4_extent *ex;
 217
 218                 /*
 219                  * Try to predict block placement assuming that we are
 220                  * filling in a file which will eventually be
 221                  * non-sparse --- i.e., in the case of libbfd writing
 222                  * an ELF object sections out-of-order but in a way
 223                  * the eventually results in a contiguous object or
 224                  * executable file, or some database extending a table
 225                  * space file.  However, this is actually somewhat
 226                  * non-ideal if we are writing a sparse file such as
 227                  * qemu or KVM writing a raw image file that is going
 228                  * to stay fairly sparse, since it will end up
 229                  * fragmenting the file system's free space.  Maybe we
 230                  * should have some hueristics or some way to allow
 231                  * userspace to pass a hint to file system,
 232                  * especially if the latter case turns out to be
 233                  * common.
 234                  */
 235                 ex = path[depth].p_ext;
 236                 if (ex) {
 237                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 238                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 239
 240                         if (block > ext_block)
 241                                 return ext_pblk + (block - ext_block);
 242                         else
 243                                 return ext_pblk - (ext_block - block);
 244                 }
 245
 246                 /* it looks like index is empty;
 247                  * try to find starting block from index itself */
 248                 if (path[depth].p_bh)
 249                         return path[depth].p_bh->b_blocknr;
 250         }
 251
 252         /* OK. use inode's group */
 253         return ext4_inode_to_goal_block(inode);
 254 }
 255
 256 /*
 257  * Allocation for a meta data block
 258  */
 259 static ext4_fsblk_t
 260 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 261                         struct ext4_ext_path *path,
 262                         struct ext4_extent *ex, int *err, unsigned int flags)
 263 {
 264         ext4_fsblk_t goal, newblock;
 265
 266         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 267         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 268                                         NULL, err);
 269         return newblock;
 270 }
 271
 272 static inline int ext4_ext_space_block(struct inode *inode, int check)
 273 {
 274         int size;
 275
 276         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 277                         / sizeof(struct ext4_extent);
 278 #ifdef AGGRESSIVE_TEST
 279         if (!check && size > 6)
 280                 size = 6;
 281 #endif
 282         return size;
 283 }
 284
 285 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 286 {
 287         int size;
 288
 289         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 290                         / sizeof(struct ext4_extent_idx);
 291 #ifdef AGGRESSIVE_TEST
 292         if (!check && size > 5)
 293                 size = 5;
 294 #endif
 295         return size;
 296 }
 297
 298 static inline int ext4_ext_space_root(struct inode *inode, int check)
 299 {
 300         int size;
 301
 302         size = sizeof(EXT4_I(inode)->i_data);
 303         size -= sizeof(struct ext4_extent_header);
 304         size /= sizeof(struct ext4_extent);
 305 #ifdef AGGRESSIVE_TEST
 306         if (!check && size > 3)
 307                 size = 3;
 308 #endif
 309         return size;
 310 }
 311
 312 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 313 {
 314         int size;
 315
 316         size = sizeof(EXT4_I(inode)->i_data);
 317         size -= sizeof(struct ext4_extent_header);
 318         size /= sizeof(struct ext4_extent_idx);
 319 #ifdef AGGRESSIVE_TEST
 320         if (!check && size > 4)
 321                 size = 4;
 322 #endif
 323         return size;
 324 }
 325
 326 static inline int
 327 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 328                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 329                            int nofail)
 330 {
 331         struct ext4_ext_path *path = *ppath;
 332         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 333         int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO;
 334
 335         if (nofail)
 336                 flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL;
 337
 338         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 339                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 340                         flags);
 341 }
 342
 343 static int
 344 ext4_ext_max_entries(struct inode *inode, int depth)
 345 {
 346         int max;
 347
 348         if (depth == ext_depth(inode)) {
 349                 if (depth == 0)
 350                         max = ext4_ext_space_root(inode, 1);
 351                 else
 352                         max = ext4_ext_space_root_idx(inode, 1);
 353         } else {
 354                 if (depth == 0)
 355                         max = ext4_ext_space_block(inode, 1);
 356                 else
 357                         max = ext4_ext_space_block_idx(inode, 1);
 358         }
 359
 360         return max;
 361 }
 362
 363 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 364 {
 365         ext4_fsblk_t block = ext4_ext_pblock(ext);
 366         int len = ext4_ext_get_actual_len(ext);
 367         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 368
 369         /*
 370          * We allow neither:
 371          *  - zero length
 372          *  - overflow/wrap-around
 373          */
 374         if (lblock + len <= lblock)
 375                 return 0;
 376         return ext4_inode_block_valid(inode, block, len);
 377 }
 378
 379 static int ext4_valid_extent_idx(struct inode *inode,
 380                                 struct ext4_extent_idx *ext_idx)
 381 {
 382         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 383
 384         return ext4_inode_block_valid(inode, block, 1);
 385 }
 386
 387 static int ext4_valid_extent_entries(struct inode *inode,
 388                                      struct ext4_extent_header *eh,
 389                                      ext4_lblk_t lblk, ext4_fsblk_t *pblk,
 390                                      int depth)
 391 {
 392         unsigned short entries;
 393         ext4_lblk_t lblock = 0;
 394         ext4_lblk_t cur = 0;
 395
 396         if (eh->eh_entries == 0)
 397                 return 1;
 398
 399         entries = le16_to_cpu(eh->eh_entries);
 400
 401         if (depth == 0) {
 402                 /* leaf entries */
 403                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 404
 405                 /*
 406                  * The logical block in the first entry should equal to
 407                  * the number in the index block.
 408                  */
 409                 if (depth != ext_depth(inode) &&
 410                     lblk != le32_to_cpu(ext->ee_block))
 411                         return 0;
 412                 while (entries) {
 413                         if (!ext4_valid_extent(inode, ext))
 414                                 return 0;
 415
 416                         /* Check for overlapping extents */
 417                         lblock = le32_to_cpu(ext->ee_block);
 418                         if (lblock < cur) {
 419                                 *pblk = ext4_ext_pblock(ext);
 420                                 return 0;
 421                         }
 422                         cur = lblock + ext4_ext_get_actual_len(ext);
 423                         ext++;
 424                         entries--;
 425                 }
 426         } else {
 427                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 428
 429                 /*
 430                  * The logical block in the first entry should equal to
 431                  * the number in the parent index block.
 432                  */
 433                 if (depth != ext_depth(inode) &&
 434                     lblk != le32_to_cpu(ext_idx->ei_block))
 435                         return 0;
 436                 while (entries) {
 437                         if (!ext4_valid_extent_idx(inode, ext_idx))
 438                                 return 0;
 439
 440                         /* Check for overlapping index extents */
 441                         lblock = le32_to_cpu(ext_idx->ei_block);
 442                         if (lblock < cur) {
 443                                 *pblk = ext4_idx_pblock(ext_idx);
 444                                 return 0;
 445                         }
 446                         ext_idx++;
 447                         entries--;
 448                         cur = lblock + 1;
 449                 }
 450         }
 451         return 1;
 452 }
 453
 454 static int __ext4_ext_check(const char *function, unsigned int line,
 455                             struct inode *inode, struct ext4_extent_header *eh,
 456                             int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk)
 457 {
 458         const char *error_msg;
 459         int max = 0, err = -EFSCORRUPTED;
 460
 461         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 462                 error_msg = "invalid magic";
 463                 goto corrupted;
 464         }
 465         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 466                 error_msg = "unexpected eh_depth";
 467                 goto corrupted;
 468         }
 469         if (unlikely(eh->eh_max == 0)) {
 470                 error_msg = "invalid eh_max";
 471                 goto corrupted;
 472         }
 473         max = ext4_ext_max_entries(inode, depth);
 474         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 475                 error_msg = "too large eh_max";
 476                 goto corrupted;
 477         }
 478         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 479                 error_msg = "invalid eh_entries";
 480                 goto corrupted;
 481         }
 482         if (unlikely((eh->eh_entries == 0) && (depth > 0))) {
 483                 error_msg = "eh_entries is 0 but eh_depth is > 0";
 484                 goto corrupted;
 485         }
 486         if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) {
 487                 error_msg = "invalid extent entries";
 488                 goto corrupted;
 489         }
 490         if (unlikely(depth > 32)) {
 491                 error_msg = "too large eh_depth";
 492                 goto corrupted;
 493         }
 494         /* Verify checksum on non-root extent tree nodes */
 495         if (ext_depth(inode) != depth &&
 496             !ext4_extent_block_csum_verify(inode, eh)) {
 497                 error_msg = "extent tree corrupted";
 498                 err = -EFSBADCRC;
 499                 goto corrupted;
 500         }
 501         return 0;
 502
 503 corrupted:
 504         ext4_error_inode_err(inode, function, line, 0, -err,
 505                              "pblk %llu bad header/extent: %s - magic %x, "
 506                              "entries %u, max %u(%u), depth %u(%u)",
 507                              (unsigned long long) pblk, error_msg,
 508                              le16_to_cpu(eh->eh_magic),
 509                              le16_to_cpu(eh->eh_entries),
 510                              le16_to_cpu(eh->eh_max),
 511                              max, le16_to_cpu(eh->eh_depth), depth);
 512         return err;
 513 }
 514
 515 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 516         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)
 517
 518 int ext4_ext_check_inode(struct inode *inode)
 519 {
 520         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 521 }
 522
 523 static void ext4_cache_extents(struct inode *inode,
 524                                struct ext4_extent_header *eh)
 525 {
 526         struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 527         ext4_lblk_t prev = 0;
 528         int i;
 529
 530         for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 531                 unsigned int status = EXTENT_STATUS_WRITTEN;
 532                 ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 533                 int len = ext4_ext_get_actual_len(ex);
 534
 535                 if (prev && (prev != lblk))
 536                         ext4_es_cache_extent(inode, prev, lblk - prev, ~0,
 537                                              EXTENT_STATUS_HOLE);
 538
 539                 if (ext4_ext_is_unwritten(ex))
 540                         status = EXTENT_STATUS_UNWRITTEN;
 541                 ext4_es_cache_extent(inode, lblk, len,
 542                                      ext4_ext_pblock(ex), status);
 543                 prev = lblk + len;
 544         }
 545 }
 546
 547 static struct buffer_head *
 548 __read_extent_tree_block(const char *function, unsigned int line,
 549                          struct inode *inode, struct ext4_extent_idx *idx,
 550                          int depth, int flags)
 551 {
 552         struct buffer_head              *bh;
 553         int                             err;
 554         gfp_t                           gfp_flags = __GFP_MOVABLE | GFP_NOFS;
 555         ext4_fsblk_t                    pblk;
 556
 557         if (flags & EXT4_EX_NOFAIL)
 558                 gfp_flags |= __GFP_NOFAIL;
 559
 560         pblk = ext4_idx_pblock(idx);
 561         bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);
 562         if (unlikely(!bh))
 563                 return ERR_PTR(-ENOMEM);
 564
 565         if (!bh_uptodate_or_lock(bh)) {
 566                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 567                 err = ext4_read_bh(bh, 0, NULL);
 568                 if (err < 0)
 569                         goto errout;
 570         }
 571         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 572                 return bh;
 573         err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh),
 574                                depth, pblk, le32_to_cpu(idx->ei_block));
 575         if (err)
 576                 goto errout;
 577         set_buffer_verified(bh);
 578         /*
 579          * If this is a leaf block, cache all of its entries
 580          */
 581         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 582                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 583                 ext4_cache_extents(inode, eh);
 584         }
 585         return bh;
 586 errout:
 587         put_bh(bh);
 588         return ERR_PTR(err);
 589
 590 }
 591
 592 #define read_extent_tree_block(inode, idx, depth, flags)                \
 593         __read_extent_tree_block(__func__, __LINE__, (inode), (idx),    \
 594                                  (depth), (flags))
 595
 596 /*
 597  * This function is called to cache a file's extent information in the
 598  * extent status tree
 599  */
 600 int ext4_ext_precache(struct inode *inode)
 601 {
 602         struct ext4_inode_info *ei = EXT4_I(inode);
 603         struct ext4_ext_path *path = NULL;
 604         struct buffer_head *bh;
 605         int i = 0, depth, ret = 0;
 606
 607         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 608                 return 0;       /* not an extent-mapped inode */
 609
 610         down_read(&ei->i_data_sem);
 611         depth = ext_depth(inode);
 612
 613         /* Don't cache anything if there are no external extent blocks */
 614         if (!depth) {
 615                 up_read(&ei->i_data_sem);
 616                 return ret;
 617         }
 618
 619         path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
 620                        GFP_NOFS);
 621         if (path == NULL) {
 622                 up_read(&ei->i_data_sem);
 623                 return -ENOMEM;
 624         }
 625
 626         path[0].p_hdr = ext_inode_hdr(inode);
 627         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 628         if (ret)
 629                 goto out;
 630         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 631         while (i >= 0) {
 632                 /*
 633                  * If this is a leaf block or we've reached the end of
 634                  * the index block, go up
 635                  */
 636                 if ((i == depth) ||
 637                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 638                         brelse(path[i].p_bh);
 639                         path[i].p_bh = NULL;
 640                         i--;
 641                         continue;
 642                 }
 643                 bh = read_extent_tree_block(inode, path[i].p_idx++,
 644                                             depth - i - 1,
 645                                             EXT4_EX_FORCE_CACHE);
 646                 if (IS_ERR(bh)) {
 647                         ret = PTR_ERR(bh);
 648                         break;
 649                 }
 650                 i++;
 651                 path[i].p_bh = bh;
 652                 path[i].p_hdr = ext_block_hdr(bh);
 653                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 654         }
 655         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 656 out:
 657         up_read(&ei->i_data_sem);
 658         ext4_free_ext_path(path);
 659         return ret;
 660 }
 661
 662 #ifdef EXT_DEBUG
 663 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 664 {
 665         int k, l = path->p_depth;
 666
 667         ext_debug(inode, "path:");
 668         for (k = 0; k <= l; k++, path++) {
 669                 if (path->p_idx) {
 670                         ext_debug(inode, "  %d->%llu",
 671                                   le32_to_cpu(path->p_idx->ei_block),
 672                                   ext4_idx_pblock(path->p_idx));
 673                 } else if (path->p_ext) {
 674                         ext_debug(inode, "  %d:[%d]%d:%llu ",
 675                                   le32_to_cpu(path->p_ext->ee_block),
 676                                   ext4_ext_is_unwritten(path->p_ext),
 677                                   ext4_ext_get_actual_len(path->p_ext),
 678                                   ext4_ext_pblock(path->p_ext));
 679                 } else
 680                         ext_debug(inode, "  []");
 681         }
 682         ext_debug(inode, "\n");
 683 }
 684
 685 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 686 {
 687         int depth = ext_depth(inode);
 688         struct ext4_extent_header *eh;
 689         struct ext4_extent *ex;
 690         int i;
 691
 692         if (!path)
 693                 return;
 694
 695         eh = path[depth].p_hdr;
 696         ex = EXT_FIRST_EXTENT(eh);
 697
 698         ext_debug(inode, "Displaying leaf extents\n");
 699
 700         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 701                 ext_debug(inode, "%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 702                           ext4_ext_is_unwritten(ex),
 703                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 704         }
 705         ext_debug(inode, "\n");
 706 }
 707
 708 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 709                         ext4_fsblk_t newblock, int level)
 710 {
 711         int depth = ext_depth(inode);
 712         struct ext4_extent *ex;
 713
 714         if (depth != level) {
 715                 struct ext4_extent_idx *idx;
 716                 idx = path[level].p_idx;
 717                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 718                         ext_debug(inode, "%d: move %d:%llu in new index %llu\n",
 719                                   level, le32_to_cpu(idx->ei_block),
 720                                   ext4_idx_pblock(idx), newblock);
 721                         idx++;
 722                 }
 723
 724                 return;
 725         }
 726
 727         ex = path[depth].p_ext;
 728         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 729                 ext_debug(inode, "move %d:%llu:[%d]%d in new leaf %llu\n",
 730                                 le32_to_cpu(ex->ee_block),
 731                                 ext4_ext_pblock(ex),
 732                                 ext4_ext_is_unwritten(ex),
 733                                 ext4_ext_get_actual_len(ex),
 734                                 newblock);
 735                 ex++;
 736         }
 737 }
 738
 739 #else
 740 #define ext4_ext_show_path(inode, path)
 741 #define ext4_ext_show_leaf(inode, path)
 742 #define ext4_ext_show_move(inode, path, newblock, level)
 743 #endif
 744
 745 /*
 746  * ext4_ext_binsearch_idx:
 747  * binary search for the closest index of the given block
 748  * the header must be checked before calling this
 749  */
 750 static void
 751 ext4_ext_binsearch_idx(struct inode *inode,
 752                         struct ext4_ext_path *path, ext4_lblk_t block)
 753 {
 754         struct ext4_extent_header *eh = path->p_hdr;
 755         struct ext4_extent_idx *r, *l, *m;
 756
 757
 758         ext_debug(inode, "binsearch for %u(idx):  ", block);
 759
 760         l = EXT_FIRST_INDEX(eh) + 1;
 761         r = EXT_LAST_INDEX(eh);
 762         while (l <= r) {
 763                 m = l + (r - l) / 2;
 764                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 765                           le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block),
 766                           r, le32_to_cpu(r->ei_block));
 767
 768                 if (block < le32_to_cpu(m->ei_block))
 769                         r = m - 1;
 770                 else
 771                         l = m + 1;
 772         }
 773
 774         path->p_idx = l - 1;
 775         ext_debug(inode, "  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 776                   ext4_idx_pblock(path->p_idx));
 777
 778 #ifdef CHECK_BINSEARCH
 779         {
 780                 struct ext4_extent_idx *chix, *ix;
 781                 int k;
 782
 783                 chix = ix = EXT_FIRST_INDEX(eh);
 784                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 785                         if (k != 0 && le32_to_cpu(ix->ei_block) <=
 786                             le32_to_cpu(ix[-1].ei_block)) {
 787                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 788                                        "first=0x%p\n", k,
 789                                        ix, EXT_FIRST_INDEX(eh));
 790                                 printk(KERN_DEBUG "%u <= %u\n",
 791                                        le32_to_cpu(ix->ei_block),
 792                                        le32_to_cpu(ix[-1].ei_block));
 793                         }
 794                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 795                                            <= le32_to_cpu(ix[-1].ei_block));
 796                         if (block < le32_to_cpu(ix->ei_block))
 797                                 break;
 798                         chix = ix;
 799                 }
 800                 BUG_ON(chix != path->p_idx);
 801         }
 802 #endif
 803
 804 }
 805
 806 /*
 807  * ext4_ext_binsearch:
 808  * binary search for closest extent of the given block
 809  * the header must be checked before calling this
 810  */
 811 static void
 812 ext4_ext_binsearch(struct inode *inode,
 813                 struct ext4_ext_path *path, ext4_lblk_t block)
 814 {
 815         struct ext4_extent_header *eh = path->p_hdr;
 816         struct ext4_extent *r, *l, *m;
 817
 818         if (eh->eh_entries == 0) {
 819                 /*
 820                  * this leaf is empty:
 821                  * we get such a leaf in split/add case
 822                  */
 823                 return;
 824         }
 825
 826         ext_debug(inode, "binsearch for %u:  ", block);
 827
 828         l = EXT_FIRST_EXTENT(eh) + 1;
 829         r = EXT_LAST_EXTENT(eh);
 830
 831         while (l <= r) {
 832                 m = l + (r - l) / 2;
 833                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 834                           le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block),
 835                           r, le32_to_cpu(r->ee_block));
 836
 837                 if (block < le32_to_cpu(m->ee_block))
 838                         r = m - 1;
 839                 else
 840                         l = m + 1;
 841         }
 842
 843         path->p_ext = l - 1;
 844         ext_debug(inode, "  -> %d:%llu:[%d]%d ",
 845                         le32_to_cpu(path->p_ext->ee_block),
 846                         ext4_ext_pblock(path->p_ext),
 847                         ext4_ext_is_unwritten(path->p_ext),
 848                         ext4_ext_get_actual_len(path->p_ext));
 849
 850 #ifdef CHECK_BINSEARCH
 851         {
 852                 struct ext4_extent *chex, *ex;
 853                 int k;
 854
 855                 chex = ex = EXT_FIRST_EXTENT(eh);
 856                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 857                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 858                                           <= le32_to_cpu(ex[-1].ee_block));
 859                         if (block < le32_to_cpu(ex->ee_block))
 860                                 break;
 861                         chex = ex;
 862                 }
 863                 BUG_ON(chex != path->p_ext);
 864         }
 865 #endif
 866
 867 }
 868
 869 void ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 870 {
 871         struct ext4_extent_header *eh;
 872
 873         eh = ext_inode_hdr(inode);
 874         eh->eh_depth = 0;
 875         eh->eh_entries = 0;
 876         eh->eh_magic = EXT4_EXT_MAGIC;
 877         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 878         eh->eh_generation = 0;
 879         ext4_mark_inode_dirty(handle, inode);
 880 }
 881
 882 struct ext4_ext_path *
 883 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 884                  struct ext4_ext_path **orig_path, int flags)
 885 {
 886         struct ext4_extent_header *eh;
 887         struct buffer_head *bh;
 888         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 889         short int depth, i, ppos = 0;
 890         int ret;
 891         gfp_t gfp_flags = GFP_NOFS;
 892
 893         if (flags & EXT4_EX_NOFAIL)
 894                 gfp_flags |= __GFP_NOFAIL;
 895
 896         eh = ext_inode_hdr(inode);
 897         depth = ext_depth(inode);
 898         if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
 899                 EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
 900                                  depth);
 901                 ret = -EFSCORRUPTED;
 902                 goto err;
 903         }
 904
 905         if (path) {
 906                 ext4_ext_drop_refs(path);
 907                 if (depth > path[0].p_maxdepth) {
 908                         kfree(path);
 909                         *orig_path = path = NULL;
 910                 }
 911         }
 912         if (!path) {
 913                 /* account possible depth increase */
 914                 path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
 915                                 gfp_flags);
 916                 if (unlikely(!path))
 917                         return ERR_PTR(-ENOMEM);
 918                 path[0].p_maxdepth = depth + 1;
 919         }
 920         path[0].p_hdr = eh;
 921         path[0].p_bh = NULL;
 922
 923         i = depth;
 924         if (!(flags & EXT4_EX_NOCACHE) && depth == 0)
 925                 ext4_cache_extents(inode, eh);
 926         /* walk through the tree */
 927         while (i) {
 928                 ext_debug(inode, "depth %d: num %d, max %d\n",
 929                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 930
 931                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 932                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 933                 path[ppos].p_depth = i;
 934                 path[ppos].p_ext = NULL;
 935
 936                 bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);
 937                 if (IS_ERR(bh)) {
 938                         ret = PTR_ERR(bh);
 939                         goto err;
 940                 }
 941
 942                 eh = ext_block_hdr(bh);
 943                 ppos++;
 944                 path[ppos].p_bh = bh;
 945                 path[ppos].p_hdr = eh;
 946         }
 947
 948         path[ppos].p_depth = i;
 949         path[ppos].p_ext = NULL;
 950         path[ppos].p_idx = NULL;
 951
 952         /* find extent */
 953         ext4_ext_binsearch(inode, path + ppos, block);
 954         /* if not an empty leaf */
 955         if (path[ppos].p_ext)
 956                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 957
 958         ext4_ext_show_path(inode, path);
 959
 960         return path;
 961
 962 err:
 963         ext4_free_ext_path(path);
 964         if (orig_path)
 965                 *orig_path = NULL;
 966         return ERR_PTR(ret);
 967 }
 968
 969 /*
 970  * ext4_ext_insert_index:
 971  * insert new index [@logical;@ptr] into the block at @curp;
 972  * check where to insert: before @curp or after @curp
 973  */
 974 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 975                                  struct ext4_ext_path *curp,
 976                                  int logical, ext4_fsblk_t ptr)
 977 {
 978         struct ext4_extent_idx *ix;
 979         int len, err;
 980
 981         err = ext4_ext_get_access(handle, inode, curp);
 982         if (err)
 983                 return err;
 984
 985         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 986                 EXT4_ERROR_INODE(inode,
 987                                  "logical %d == ei_block %d!",
 988                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 989                 return -EFSCORRUPTED;
 990         }
 991
 992         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 993                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 994                 EXT4_ERROR_INODE(inode,
 995                                  "eh_entries %d >= eh_max %d!",
 996                                  le16_to_cpu(curp->p_hdr->eh_entries),
 997                                  le16_to_cpu(curp->p_hdr->eh_max));
 998                 return -EFSCORRUPTED;
 999         }
1000
1001         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
1002                 /* insert after */
1003                 ext_debug(inode, "insert new index %d after: %llu\n",
1004                           logical, ptr);
1005                 ix = curp->p_idx + 1;
1006         } else {
1007                 /* insert before */
1008                 ext_debug(inode, "insert new index %d before: %llu\n",
1009                           logical, ptr);
1010                 ix = curp->p_idx;
1011         }
1012
1013         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
1014         BUG_ON(len < 0);
1015         if (len > 0) {
1016                 ext_debug(inode, "insert new index %d: "
1017                                 "move %d indices from 0x%p to 0x%p\n",
1018                                 logical, len, ix, ix + 1);
1019                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
1020         }
1021
1022         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
1023                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1024                 return -EFSCORRUPTED;
1025         }
1026
1027         ix->ei_block = cpu_to_le32(logical);
1028         ext4_idx_store_pblock(ix, ptr);
1029         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1030
1031         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1032                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1033                 return -EFSCORRUPTED;
1034         }
1035
1036         err = ext4_ext_dirty(handle, inode, curp);
1037         ext4_std_error(inode->i_sb, err);
1038
1039         return err;
1040 }
1041
1042 /*
1043  * ext4_ext_split:
1044  * inserts new subtree into the path, using free index entry
1045  * at depth @at:
1046  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1047  * - makes decision where to split
1048  * - moves remaining extents and index entries (right to the split point)
1049  *   into the newly allocated blocks
1050  * - initializes subtree
1051  */
1052 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1053                           unsigned int flags,
1054                           struct ext4_ext_path *path,
1055                           struct ext4_extent *newext, int at)
1056 {
1057         struct buffer_head *bh = NULL;
1058         int depth = ext_depth(inode);
1059         struct ext4_extent_header *neh;
1060         struct ext4_extent_idx *fidx;
1061         int i = at, k, m, a;
1062         ext4_fsblk_t newblock, oldblock;
1063         __le32 border;
1064         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1065         gfp_t gfp_flags = GFP_NOFS;
1066         int err = 0;
1067         size_t ext_size = 0;
1068
1069         if (flags & EXT4_EX_NOFAIL)
1070                 gfp_flags |= __GFP_NOFAIL;
1071
1072         /* make decision: where to split? */
1073         /* FIXME: now decision is simplest: at current extent */
1074
1075         /* if current leaf will be split, then we should use
1076          * border from split point */
1077         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1078                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1079                 return -EFSCORRUPTED;
1080         }
1081         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1082                 border = path[depth].p_ext[1].ee_block;
1083                 ext_debug(inode, "leaf will be split."
1084                                 " next leaf starts at %d\n",
1085                                   le32_to_cpu(border));
1086         } else {
1087                 border = newext->ee_block;
1088                 ext_debug(inode, "leaf will be added."
1089                                 " next leaf starts at %d\n",
1090                                 le32_to_cpu(border));
1091         }
1092
1093         /*
1094          * If error occurs, then we break processing
1095          * and mark filesystem read-only. index won't
1096          * be inserted and tree will be in consistent
1097          * state. Next mount will repair buffers too.
1098          */
1099
1100         /*
1101          * Get array to track all allocated blocks.
1102          * We need this to handle errors and free blocks
1103          * upon them.
1104          */
1105         ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), gfp_flags);
1106         if (!ablocks)
1107                 return -ENOMEM;
1108
1109         /* allocate all needed blocks */
1110         ext_debug(inode, "allocate %d blocks for indexes/leaf\n", depth - at);
1111         for (a = 0; a < depth - at; a++) {
1112                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1113                                                    newext, &err, flags);
1114                 if (newblock == 0)
1115                         goto cleanup;
1116                 ablocks[a] = newblock;
1117         }
1118
1119         /* initialize new leaf */
1120         newblock = ablocks[--a];
1121         if (unlikely(newblock == 0)) {
1122                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1123                 err = -EFSCORRUPTED;
1124                 goto cleanup;
1125         }
1126         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1127         if (unlikely(!bh)) {
1128                 err = -ENOMEM;
1129                 goto cleanup;
1130         }
1131         lock_buffer(bh);
1132
1133         err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1134                                              EXT4_JTR_NONE);
1135         if (err)
1136                 goto cleanup;
1137
1138         neh = ext_block_hdr(bh);
1139         neh->eh_entries = 0;
1140         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1141         neh->eh_magic = EXT4_EXT_MAGIC;
1142         neh->eh_depth = 0;
1143         neh->eh_generation = 0;
1144
1145         /* move remainder of path[depth] to the new leaf */
1146         if (unlikely(path[depth].p_hdr->eh_entries !=
1147                      path[depth].p_hdr->eh_max)) {
1148                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1149                                  path[depth].p_hdr->eh_entries,
1150                                  path[depth].p_hdr->eh_max);
1151                 err = -EFSCORRUPTED;
1152                 goto cleanup;
1153         }
1154         /* start copy from next extent */
1155         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1156         ext4_ext_show_move(inode, path, newblock, depth);
1157         if (m) {
1158                 struct ext4_extent *ex;
1159                 ex = EXT_FIRST_EXTENT(neh);
1160                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1161                 le16_add_cpu(&neh->eh_entries, m);
1162         }
1163
1164         /* zero out unused area in the extent block */
1165         ext_size = sizeof(struct ext4_extent_header) +
1166                 sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries);
1167         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1168         ext4_extent_block_csum_set(inode, neh);
1169         set_buffer_uptodate(bh);
1170         unlock_buffer(bh);
1171
1172         err = ext4_handle_dirty_metadata(handle, inode, bh);
1173         if (err)
1174                 goto cleanup;
1175         brelse(bh);
1176         bh = NULL;
1177
1178         /* correct old leaf */
1179         if (m) {
1180                 err = ext4_ext_get_access(handle, inode, path + depth);
1181                 if (err)
1182                         goto cleanup;
1183                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1184                 err = ext4_ext_dirty(handle, inode, path + depth);
1185                 if (err)
1186                         goto cleanup;
1187
1188         }
1189
1190         /* create intermediate indexes */
1191         k = depth - at - 1;
1192         if (unlikely(k < 0)) {
1193                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1194                 err = -EFSCORRUPTED;
1195                 goto cleanup;
1196         }
1197         if (k)
1198                 ext_debug(inode, "create %d intermediate indices\n", k);
1199         /* insert new index into current index block */
1200         /* current depth stored in i var */
1201         i = depth - 1;
1202         while (k--) {
1203                 oldblock = newblock;
1204                 newblock = ablocks[--a];
1205                 bh = sb_getblk(inode->i_sb, newblock);
1206                 if (unlikely(!bh)) {
1207                         err = -ENOMEM;
1208                         goto cleanup;
1209                 }
1210                 lock_buffer(bh);
1211
1212                 err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1213                                                      EXT4_JTR_NONE);
1214                 if (err)
1215                         goto cleanup;
1216
1217                 neh = ext_block_hdr(bh);
1218                 neh->eh_entries = cpu_to_le16(1);
1219                 neh->eh_magic = EXT4_EXT_MAGIC;
1220                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1221                 neh->eh_depth = cpu_to_le16(depth - i);
1222                 neh->eh_generation = 0;
1223                 fidx = EXT_FIRST_INDEX(neh);
1224                 fidx->ei_block = border;
1225                 ext4_idx_store_pblock(fidx, oldblock);
1226
1227                 ext_debug(inode, "int.index at %d (block %llu): %u -> %llu\n",
1228                                 i, newblock, le32_to_cpu(border), oldblock);
1229
1230                 /* move remainder of path[i] to the new index block */
1231                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1232                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1233                         EXT4_ERROR_INODE(inode,
1234                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1235                                          le32_to_cpu(path[i].p_ext->ee_block));
1236                         err = -EFSCORRUPTED;
1237                         goto cleanup;
1238                 }
1239                 /* start copy indexes */
1240                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1241                 ext_debug(inode, "cur 0x%p, last 0x%p\n", path[i].p_idx,
1242                                 EXT_MAX_INDEX(path[i].p_hdr));
1243                 ext4_ext_show_move(inode, path, newblock, i);
1244                 if (m) {
1245                         memmove(++fidx, path[i].p_idx,
1246                                 sizeof(struct ext4_extent_idx) * m);
1247                         le16_add_cpu(&neh->eh_entries, m);
1248                 }
1249                 /* zero out unused area in the extent block */
1250                 ext_size = sizeof(struct ext4_extent_header) +
1251                    (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));
1252                 memset(bh->b_data + ext_size, 0,
1253                         inode->i_sb->s_blocksize - ext_size);
1254                 ext4_extent_block_csum_set(inode, neh);
1255                 set_buffer_uptodate(bh);
1256                 unlock_buffer(bh);
1257
1258                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1259                 if (err)
1260                         goto cleanup;
1261                 brelse(bh);
1262                 bh = NULL;
1263
1264                 /* correct old index */
1265                 if (m) {
1266                         err = ext4_ext_get_access(handle, inode, path + i);
1267                         if (err)
1268                                 goto cleanup;
1269                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1270                         err = ext4_ext_dirty(handle, inode, path + i);
1271                         if (err)
1272                                 goto cleanup;
1273                 }
1274
1275                 i--;
1276         }
1277
1278         /* insert new index */
1279         err = ext4_ext_insert_index(handle, inode, path + at,
1280                                     le32_to_cpu(border), newblock);
1281
1282 cleanup:
1283         if (bh) {
1284                 if (buffer_locked(bh))
1285                         unlock_buffer(bh);
1286                 brelse(bh);
1287         }
1288
1289         if (err) {
1290                 /* free all allocated blocks in error case */
1291                 for (i = 0; i < depth; i++) {
1292                         if (!ablocks[i])
1293                                 continue;
1294                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1295                                          EXT4_FREE_BLOCKS_METADATA);
1296                 }
1297         }
1298         kfree(ablocks);
1299
1300         return err;
1301 }
1302
1303 /*
1304  * ext4_ext_grow_indepth:
1305  * implements tree growing procedure:
1306  * - allocates new block
1307  * - moves top-level data (index block or leaf) into the new block
1308  * - initializes new top-level, creating index that points to the
1309  *   just created block
1310  */
1311 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1312                                  unsigned int flags)
1313 {
1314         struct ext4_extent_header *neh;
1315         struct buffer_head *bh;
1316         ext4_fsblk_t newblock, goal = 0;
1317         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1318         int err = 0;
1319         size_t ext_size = 0;
1320
1321         /* Try to prepend new index to old one */
1322         if (ext_depth(inode))
1323                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1324         if (goal > le32_to_cpu(es->s_first_data_block)) {
1325                 flags |= EXT4_MB_HINT_TRY_GOAL;
1326                 goal--;
1327         } else
1328                 goal = ext4_inode_to_goal_block(inode);
1329         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1330                                         NULL, &err);
1331         if (newblock == 0)
1332                 return err;
1333
1334         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1335         if (unlikely(!bh))
1336                 return -ENOMEM;
1337         lock_buffer(bh);
1338
1339         err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1340                                              EXT4_JTR_NONE);
1341         if (err) {
1342                 unlock_buffer(bh);
1343                 goto out;
1344         }
1345
1346         ext_size = sizeof(EXT4_I(inode)->i_data);
1347         /* move top-level index/leaf into new block */
1348         memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);
1349         /* zero out unused area in the extent block */
1350         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1351
1352         /* set size of new block */
1353         neh = ext_block_hdr(bh);
1354         /* old root could have indexes or leaves
1355          * so calculate e_max right way */
1356         if (ext_depth(inode))
1357                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1358         else
1359                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1360         neh->eh_magic = EXT4_EXT_MAGIC;
1361         ext4_extent_block_csum_set(inode, neh);
1362         set_buffer_uptodate(bh);
1363         set_buffer_verified(bh);
1364         unlock_buffer(bh);
1365
1366         err = ext4_handle_dirty_metadata(handle, inode, bh);
1367         if (err)
1368                 goto out;
1369
1370         /* Update top-level index: num,max,pointer */
1371         neh = ext_inode_hdr(inode);
1372         neh->eh_entries = cpu_to_le16(1);
1373         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1374         if (neh->eh_depth == 0) {
1375                 /* Root extent block becomes index block */
1376                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1377                 EXT_FIRST_INDEX(neh)->ei_block =
1378                         EXT_FIRST_EXTENT(neh)->ee_block;
1379         }
1380         ext_debug(inode, "new root: num %d(%d), lblock %d, ptr %llu\n",
1381                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1382                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1383                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1384
1385         le16_add_cpu(&neh->eh_depth, 1);
1386         err = ext4_mark_inode_dirty(handle, inode);
1387 out:
1388         brelse(bh);
1389
1390         return err;
1391 }
1392
1393 /*
1394  * ext4_ext_create_new_leaf:
1395  * finds empty index and adds new leaf.
1396  * if no free index is found, then it requests in-depth growing.
1397  */
1398 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1399                                     unsigned int mb_flags,
1400                                     unsigned int gb_flags,
1401                                     struct ext4_ext_path **ppath,
1402                                     struct ext4_extent *newext)
1403 {
1404         struct ext4_ext_path *path = *ppath;
1405         struct ext4_ext_path *curp;
1406         int depth, i, err = 0;
1407
1408 repeat:
1409         i = depth = ext_depth(inode);
1410
1411         /* walk up to the tree and look for free index entry */
1412         curp = path + depth;
1413         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1414                 i--;
1415                 curp--;
1416         }
1417
1418         /* we use already allocated block for index block,
1419          * so subsequent data blocks should be contiguous */
1420         if (EXT_HAS_FREE_INDEX(curp)) {
1421                 /* if we found index with free entry, then use that
1422                  * entry: create all needed subtree and add new leaf */
1423                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1424                 if (err)
1425                         goto out;
1426
1427                 /* refill path */
1428                 path = ext4_find_extent(inode,
1429                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1430                                     ppath, gb_flags);
1431                 if (IS_ERR(path))
1432                         err = PTR_ERR(path);
1433         } else {
1434                 /* tree is full, time to grow in depth */
1435                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1436                 if (err)
1437                         goto out;
1438
1439                 /* refill path */
1440                 path = ext4_find_extent(inode,
1441                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1442                                     ppath, gb_flags);
1443                 if (IS_ERR(path)) {
1444                         err = PTR_ERR(path);
1445                         goto out;
1446                 }
1447
1448                 /*
1449                  * only first (depth 0 -> 1) produces free space;
1450                  * in all other cases we have to split the grown tree
1451                  */
1452                 depth = ext_depth(inode);
1453                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1454                         /* now we need to split */
1455                         goto repeat;
1456                 }
1457         }
1458
1459 out:
1460         return err;
1461 }
1462
1463 /*
1464  * search the closest allocated block to the left for *logical
1465  * and returns it at @logical + it's physical address at @phys
1466  * if *logical is the smallest allocated block, the function
1467  * returns 0 at @phys
1468  * return value contains 0 (success) or error code
1469  */
1470 static int ext4_ext_search_left(struct inode *inode,
1471                                 struct ext4_ext_path *path,
1472                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1473 {
1474         struct ext4_extent_idx *ix;
1475         struct ext4_extent *ex;
1476         int depth, ee_len;
1477
1478         if (unlikely(path == NULL)) {
1479                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1480                 return -EFSCORRUPTED;
1481         }
1482         depth = path->p_depth;
1483         *phys = 0;
1484
1485         if (depth == 0 && path->p_ext == NULL)
1486                 return 0;
1487
1488         /* usually extent in the path covers blocks smaller
1489          * then *logical, but it can be that extent is the
1490          * first one in the file */
1491
1492         ex = path[depth].p_ext;
1493         ee_len = ext4_ext_get_actual_len(ex);
1494         if (*logical < le32_to_cpu(ex->ee_block)) {
1495                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1496                         EXT4_ERROR_INODE(inode,
1497                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1498                                          *logical, le32_to_cpu(ex->ee_block));
1499                         return -EFSCORRUPTED;
1500                 }
1501                 while (--depth >= 0) {
1502                         ix = path[depth].p_idx;
1503                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1504                                 EXT4_ERROR_INODE(inode,
1505                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1506                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1507                                   le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block),
1508                                   depth);
1509                                 return -EFSCORRUPTED;
1510                         }
1511                 }
1512                 return 0;
1513         }
1514
1515         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1516                 EXT4_ERROR_INODE(inode,
1517                                  "logical %d < ee_block %d + ee_len %d!",
1518                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1519                 return -EFSCORRUPTED;
1520         }
1521
1522         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1523         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1524         return 0;
1525 }
1526
1527 /*
1528  * Search the closest allocated block to the right for *logical
1529  * and returns it at @logical + it's physical address at @phys.
1530  * If not exists, return 0 and @phys is set to 0. We will return
1531  * 1 which means we found an allocated block and ret_ex is valid.
1532  * Or return a (< 0) error code.
1533  */
1534 static int ext4_ext_search_right(struct inode *inode,
1535                                  struct ext4_ext_path *path,
1536                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1537                                  struct ext4_extent *ret_ex)
1538 {
1539         struct buffer_head *bh = NULL;
1540         struct ext4_extent_header *eh;
1541         struct ext4_extent_idx *ix;
1542         struct ext4_extent *ex;
1543         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1544         int ee_len;
1545
1546         if (unlikely(path == NULL)) {
1547                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1548                 return -EFSCORRUPTED;
1549         }
1550         depth = path->p_depth;
1551         *phys = 0;
1552
1553         if (depth == 0 && path->p_ext == NULL)
1554                 return 0;
1555
1556         /* usually extent in the path covers blocks smaller
1557          * then *logical, but it can be that extent is the
1558          * first one in the file */
1559
1560         ex = path[depth].p_ext;
1561         ee_len = ext4_ext_get_actual_len(ex);
1562         if (*logical < le32_to_cpu(ex->ee_block)) {
1563                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1564                         EXT4_ERROR_INODE(inode,
1565                                          "first_extent(path[%d].p_hdr) != ex",
1566                                          depth);
1567                         return -EFSCORRUPTED;
1568                 }
1569                 while (--depth >= 0) {
1570                         ix = path[depth].p_idx;
1571                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1572                                 EXT4_ERROR_INODE(inode,
1573                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1574                                                  *logical);
1575                                 return -EFSCORRUPTED;
1576                         }
1577                 }
1578                 goto found_extent;
1579         }
1580
1581         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1582                 EXT4_ERROR_INODE(inode,
1583                                  "logical %d < ee_block %d + ee_len %d!",
1584                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1585                 return -EFSCORRUPTED;
1586         }
1587
1588         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1589                 /* next allocated block in this leaf */
1590                 ex++;
1591                 goto found_extent;
1592         }
1593
1594         /* go up and search for index to the right */
1595         while (--depth >= 0) {
1596                 ix = path[depth].p_idx;
1597                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1598                         goto got_index;
1599         }
1600
1601         /* we've gone up to the root and found no index to the right */
1602         return 0;
1603
1604 got_index:
1605         /* we've found index to the right, let's
1606          * follow it and find the closest allocated
1607          * block to the right */
1608         ix++;
1609         while (++depth < path->p_depth) {
1610                 /* subtract from p_depth to get proper eh_depth */
1611                 bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
1612                 if (IS_ERR(bh))
1613                         return PTR_ERR(bh);
1614                 eh = ext_block_hdr(bh);
1615                 ix = EXT_FIRST_INDEX(eh);
1616                 put_bh(bh);
1617         }
1618
1619         bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
1620         if (IS_ERR(bh))
1621                 return PTR_ERR(bh);
1622         eh = ext_block_hdr(bh);
1623         ex = EXT_FIRST_EXTENT(eh);
1624 found_extent:
1625         *logical = le32_to_cpu(ex->ee_block);
1626         *phys = ext4_ext_pblock(ex);
1627         if (ret_ex)
1628                 *ret_ex = *ex;
1629         if (bh)
1630                 put_bh(bh);
1631         return 1;
1632 }
1633
1634 /*
1635  * ext4_ext_next_allocated_block:
1636  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1637  * NOTE: it considers block number from index entry as
1638  * allocated block. Thus, index entries have to be consistent
1639  * with leaves.
1640  */
1641 ext4_lblk_t
1642 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1643 {
1644         int depth;
1645
1646         BUG_ON(path == NULL);
1647         depth = path->p_depth;
1648
1649         if (depth == 0 && path->p_ext == NULL)
1650                 return EXT_MAX_BLOCKS;
1651
1652         while (depth >= 0) {
1653                 struct ext4_ext_path *p = &path[depth];
1654
1655                 if (depth == path->p_depth) {
1656                         /* leaf */
1657                         if (p->p_ext && p->p_ext != EXT_LAST_EXTENT(p->p_hdr))
1658                                 return le32_to_cpu(p->p_ext[1].ee_block);
1659                 } else {
1660                         /* index */
1661                         if (p->p_idx != EXT_LAST_INDEX(p->p_hdr))
1662                                 return le32_to_cpu(p->p_idx[1].ei_block);
1663                 }
1664                 depth--;
1665         }
1666
1667         return EXT_MAX_BLOCKS;
1668 }
1669
1670 /*
1671  * ext4_ext_next_leaf_block:
1672  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1673  */
1674 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1675 {
1676         int depth;
1677
1678         BUG_ON(path == NULL);
1679         depth = path->p_depth;
1680
1681         /* zero-tree has no leaf blocks at all */
1682         if (depth == 0)
1683                 return EXT_MAX_BLOCKS;
1684
1685         /* go to index block */
1686         depth--;
1687
1688         while (depth >= 0) {
1689                 if (path[depth].p_idx !=
1690                                 EXT_LAST_INDEX(path[depth].p_hdr))
1691                         return (ext4_lblk_t)
1692                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1693                 depth--;
1694         }
1695
1696         return EXT_MAX_BLOCKS;
1697 }
1698
1699 /*
1700  * ext4_ext_correct_indexes:
1701  * if leaf gets modified and modified extent is first in the leaf,
1702  * then we have to correct all indexes above.
1703  * TODO: do we need to correct tree in all cases?
1704  */
1705 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1706                                 struct ext4_ext_path *path)
1707 {
1708         struct ext4_extent_header *eh;
1709         int depth = ext_depth(inode);
1710         struct ext4_extent *ex;
1711         __le32 border;
1712         int k, err = 0;
1713
1714         eh = path[depth].p_hdr;
1715         ex = path[depth].p_ext;
1716
1717         if (unlikely(ex == NULL || eh == NULL)) {
1718                 EXT4_ERROR_INODE(inode,
1719                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1720                 return -EFSCORRUPTED;
1721         }
1722
1723         if (depth == 0) {
1724                 /* there is no tree at all */
1725                 return 0;
1726         }
1727
1728         if (ex != EXT_FIRST_EXTENT(eh)) {
1729                 /* we correct tree if first leaf got modified only */
1730                 return 0;
1731         }
1732
1733         /*
1734          * TODO: we need correction if border is smaller than current one
1735          */
1736         k = depth - 1;
1737         border = path[depth].p_ext->ee_block;
1738         err = ext4_ext_get_access(handle, inode, path + k);
1739         if (err)
1740                 return err;
1741         path[k].p_idx->ei_block = border;
1742         err = ext4_ext_dirty(handle, inode, path + k);
1743         if (err)
1744                 return err;
1745
1746         while (k--) {
1747                 /* change all left-side indexes */
1748                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1749                         break;
1750                 err = ext4_ext_get_access(handle, inode, path + k);
1751                 if (err)
1752                         break;
1753                 path[k].p_idx->ei_block = border;
1754                 err = ext4_ext_dirty(handle, inode, path + k);
1755                 if (err)
1756                         break;
1757         }
1758
1759         return err;
1760 }
1761
1762 static int ext4_can_extents_be_merged(struct inode *inode,
1763                                       struct ext4_extent *ex1,
1764                                       struct ext4_extent *ex2)
1765 {
1766         unsigned short ext1_ee_len, ext2_ee_len;
1767
1768         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1769                 return 0;
1770
1771         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1772         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1773
1774         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1775                         le32_to_cpu(ex2->ee_block))
1776                 return 0;
1777
1778         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1779                 return 0;
1780
1781         if (ext4_ext_is_unwritten(ex1) &&
1782             ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)
1783                 return 0;
1784 #ifdef AGGRESSIVE_TEST
1785         if (ext1_ee_len >= 4)
1786                 return 0;
1787 #endif
1788
1789         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1790                 return 1;
1791         return 0;
1792 }
1793
1794 /*
1795  * This function tries to merge the "ex" extent to the next extent in the tree.
1796  * It always tries to merge towards right. If you want to merge towards
1797  * left, pass "ex - 1" as argument instead of "ex".
1798  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1799  * 1 if they got merged.
1800  */
1801 static int ext4_ext_try_to_merge_right(struct inode *inode,
1802                                  struct ext4_ext_path *path,
1803                                  struct ext4_extent *ex)
1804 {
1805         struct ext4_extent_header *eh;
1806         unsigned int depth, len;
1807         int merge_done = 0, unwritten;
1808
1809         depth = ext_depth(inode);
1810         BUG_ON(path[depth].p_hdr == NULL);
1811         eh = path[depth].p_hdr;
1812
1813         while (ex < EXT_LAST_EXTENT(eh)) {
1814                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1815                         break;
1816                 /* merge with next extent! */
1817                 unwritten = ext4_ext_is_unwritten(ex);
1818                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1819                                 + ext4_ext_get_actual_len(ex + 1));
1820                 if (unwritten)
1821                         ext4_ext_mark_unwritten(ex);
1822
1823                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1824                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1825                                 * sizeof(struct ext4_extent);
1826                         memmove(ex + 1, ex + 2, len);
1827                 }
1828                 le16_add_cpu(&eh->eh_entries, -1);
1829                 merge_done = 1;
1830                 WARN_ON(eh->eh_entries == 0);
1831                 if (!eh->eh_entries)
1832                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1833         }
1834
1835         return merge_done;
1836 }
1837
1838 /*
1839  * This function does a very simple check to see if we can collapse
1840  * an extent tree with a single extent tree leaf block into the inode.
1841  */
1842 static void ext4_ext_try_to_merge_up(handle_t *handle,
1843                                      struct inode *inode,
1844                                      struct ext4_ext_path *path)
1845 {
1846         size_t s;
1847         unsigned max_root = ext4_ext_space_root(inode, 0);
1848         ext4_fsblk_t blk;
1849
1850         if ((path[0].p_depth != 1) ||
1851             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1852             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1853                 return;
1854
1855         /*
1856          * We need to modify the block allocation bitmap and the block
1857          * group descriptor to release the extent tree block.  If we
1858          * can't get the journal credits, give up.
1859          */
1860         if (ext4_journal_extend(handle, 2,
1861                         ext4_free_metadata_revoke_credits(inode->i_sb, 1)))
1862                 return;
1863
1864         /*
1865          * Copy the extent data up to the inode
1866          */
1867         blk = ext4_idx_pblock(path[0].p_idx);
1868         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1869                 sizeof(struct ext4_extent_idx);
1870         s += sizeof(struct ext4_extent_header);
1871
1872         path[1].p_maxdepth = path[0].p_maxdepth;
1873         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1874         path[0].p_depth = 0;
1875         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1876                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1877         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1878
1879         brelse(path[1].p_bh);
1880         ext4_free_blocks(handle, inode, NULL, blk, 1,
1881                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1882 }
1883
1884 /*
1885  * This function tries to merge the @ex extent to neighbours in the tree, then
1886  * tries to collapse the extent tree into the inode.
1887  */
1888 static void ext4_ext_try_to_merge(handle_t *handle,
1889                                   struct inode *inode,
1890                                   struct ext4_ext_path *path,
1891                                   struct ext4_extent *ex)
1892 {
1893         struct ext4_extent_header *eh;
1894         unsigned int depth;
1895         int merge_done = 0;
1896
1897         depth = ext_depth(inode);
1898         BUG_ON(path[depth].p_hdr == NULL);
1899         eh = path[depth].p_hdr;
1900
1901         if (ex > EXT_FIRST_EXTENT(eh))
1902                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1903
1904         if (!merge_done)
1905                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1906
1907         ext4_ext_try_to_merge_up(handle, inode, path);
1908 }
1909
1910 /*
1911  * check if a portion of the "newext" extent overlaps with an
1912  * existing extent.
1913  *
1914  * If there is an overlap discovered, it updates the length of the newext
1915  * such that there will be no overlap, and then returns 1.
1916  * If there is no overlap found, it returns 0.
1917  */
1918 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1919                                            struct inode *inode,
1920                                            struct ext4_extent *newext,
1921                                            struct ext4_ext_path *path)
1922 {
1923         ext4_lblk_t b1, b2;
1924         unsigned int depth, len1;
1925         unsigned int ret = 0;
1926
1927         b1 = le32_to_cpu(newext->ee_block);
1928         len1 = ext4_ext_get_actual_len(newext);
1929         depth = ext_depth(inode);
1930         if (!path[depth].p_ext)
1931                 goto out;
1932         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1933
1934         /*
1935          * get the next allocated block if the extent in the path
1936          * is before the requested block(s)
1937          */
1938         if (b2 < b1) {
1939                 b2 = ext4_ext_next_allocated_block(path);
1940                 if (b2 == EXT_MAX_BLOCKS)
1941                         goto out;
1942                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1943         }
1944
1945         /* check for wrap through zero on extent logical start block*/
1946         if (b1 + len1 < b1) {
1947                 len1 = EXT_MAX_BLOCKS - b1;
1948                 newext->ee_len = cpu_to_le16(len1);
1949                 ret = 1;
1950         }
1951
1952         /* check for overlap */
1953         if (b1 + len1 > b2) {
1954                 newext->ee_len = cpu_to_le16(b2 - b1);
1955                 ret = 1;
1956         }
1957 out:
1958         return ret;
1959 }
1960
1961 /*
1962  * ext4_ext_insert_extent:
1963  * tries to merge requested extent into the existing extent or
1964  * inserts requested extent as new one into the tree,
1965  * creating new leaf in the no-space case.
1966  */
1967 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1968                                 struct ext4_ext_path **ppath,
1969                                 struct ext4_extent *newext, int gb_flags)
1970 {
1971         struct ext4_ext_path *path = *ppath;
1972         struct ext4_extent_header *eh;
1973         struct ext4_extent *ex, *fex;
1974         struct ext4_extent *nearex; /* nearest extent */
1975         struct ext4_ext_path *npath = NULL;
1976         int depth, len, err;
1977         ext4_lblk_t next;
1978         int mb_flags = 0, unwritten;
1979
1980         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1981                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1982         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1983                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1984                 return -EFSCORRUPTED;
1985         }
1986         depth = ext_depth(inode);
1987         ex = path[depth].p_ext;
1988         eh = path[depth].p_hdr;
1989         if (unlikely(path[depth].p_hdr == NULL)) {
1990                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1991                 return -EFSCORRUPTED;
1992         }
1993
1994         /* try to insert block into found extent and return */
1995         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1996
1997                 /*
1998                  * Try to see whether we should rather test the extent on
1999                  * right from ex, or from the left of ex. This is because
2000                  * ext4_find_extent() can return either extent on the
2001                  * left, or on the right from the searched position. This
2002                  * will make merging more effective.
2003                  */
2004                 if (ex < EXT_LAST_EXTENT(eh) &&
2005                     (le32_to_cpu(ex->ee_block) +
2006                     ext4_ext_get_actual_len(ex) <
2007                     le32_to_cpu(newext->ee_block))) {
2008                         ex += 1;
2009                         goto prepend;
2010                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
2011                            (le32_to_cpu(newext->ee_block) +
2012                            ext4_ext_get_actual_len(newext) <
2013                            le32_to_cpu(ex->ee_block)))
2014                         ex -= 1;
2015
2016                 /* Try to append newex to the ex */
2017                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
2018                         ext_debug(inode, "append [%d]%d block to %u:[%d]%d"
2019                                   "(from %llu)\n",
2020                                   ext4_ext_is_unwritten(newext),
2021                                   ext4_ext_get_actual_len(newext),
2022                                   le32_to_cpu(ex->ee_block),
2023                                   ext4_ext_is_unwritten(ex),
2024                                   ext4_ext_get_actual_len(ex),
2025                                   ext4_ext_pblock(ex));
2026                         err = ext4_ext_get_access(handle, inode,
2027                                                   path + depth);
2028                         if (err)
2029                                 return err;
2030                         unwritten = ext4_ext_is_unwritten(ex);
2031                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2032                                         + ext4_ext_get_actual_len(newext));
2033                         if (unwritten)
2034                                 ext4_ext_mark_unwritten(ex);
2035                         nearex = ex;
2036                         goto merge;
2037                 }
2038
2039 prepend:
2040                 /* Try to prepend newex to the ex */
2041                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2042                         ext_debug(inode, "prepend %u[%d]%d block to %u:[%d]%d"
2043                                   "(from %llu)\n",
2044                                   le32_to_cpu(newext->ee_block),
2045                                   ext4_ext_is_unwritten(newext),
2046                                   ext4_ext_get_actual_len(newext),
2047                                   le32_to_cpu(ex->ee_block),
2048                                   ext4_ext_is_unwritten(ex),
2049                                   ext4_ext_get_actual_len(ex),
2050                                   ext4_ext_pblock(ex));
2051                         err = ext4_ext_get_access(handle, inode,
2052                                                   path + depth);
2053                         if (err)
2054                                 return err;
2055
2056                         unwritten = ext4_ext_is_unwritten(ex);
2057                         ex->ee_block = newext->ee_block;
2058                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2059                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2060                                         + ext4_ext_get_actual_len(newext));
2061                         if (unwritten)
2062                                 ext4_ext_mark_unwritten(ex);
2063                         nearex = ex;
2064                         goto merge;
2065                 }
2066         }
2067
2068         depth = ext_depth(inode);
2069         eh = path[depth].p_hdr;
2070         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2071                 goto has_space;
2072
2073         /* probably next leaf has space for us? */
2074         fex = EXT_LAST_EXTENT(eh);
2075         next = EXT_MAX_BLOCKS;
2076         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2077                 next = ext4_ext_next_leaf_block(path);
2078         if (next != EXT_MAX_BLOCKS) {
2079                 ext_debug(inode, "next leaf block - %u\n", next);
2080                 BUG_ON(npath != NULL);
2081                 npath = ext4_find_extent(inode, next, NULL, gb_flags);
2082                 if (IS_ERR(npath))
2083                         return PTR_ERR(npath);
2084                 BUG_ON(npath->p_depth != path->p_depth);
2085                 eh = npath[depth].p_hdr;
2086                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2087                         ext_debug(inode, "next leaf isn't full(%d)\n",
2088                                   le16_to_cpu(eh->eh_entries));
2089                         path = npath;
2090                         goto has_space;
2091                 }
2092                 ext_debug(inode, "next leaf has no free space(%d,%d)\n",
2093                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2094         }
2095
2096         /*
2097          * There is no free space in the found leaf.
2098          * We're gonna add a new leaf in the tree.
2099          */
2100         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2101                 mb_flags |= EXT4_MB_USE_RESERVED;
2102         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2103                                        ppath, newext);
2104         if (err)
2105                 goto cleanup;
2106         depth = ext_depth(inode);
2107         eh = path[depth].p_hdr;
2108
2109 has_space:
2110         nearex = path[depth].p_ext;
2111
2112         err = ext4_ext_get_access(handle, inode, path + depth);
2113         if (err)
2114                 goto cleanup;
2115
2116         if (!nearex) {
2117                 /* there is no extent in this leaf, create first one */
2118                 ext_debug(inode, "first extent in the leaf: %u:%llu:[%d]%d\n",
2119                                 le32_to_cpu(newext->ee_block),
2120                                 ext4_ext_pblock(newext),
2121                                 ext4_ext_is_unwritten(newext),
2122                                 ext4_ext_get_actual_len(newext));
2123                 nearex = EXT_FIRST_EXTENT(eh);
2124         } else {
2125                 if (le32_to_cpu(newext->ee_block)
2126                            > le32_to_cpu(nearex->ee_block)) {
2127                         /* Insert after */
2128                         ext_debug(inode, "insert %u:%llu:[%d]%d before: "
2129                                         "nearest %p\n",
2130                                         le32_to_cpu(newext->ee_block),
2131                                         ext4_ext_pblock(newext),
2132                                         ext4_ext_is_unwritten(newext),
2133                                         ext4_ext_get_actual_len(newext),
2134                                         nearex);
2135                         nearex++;
2136                 } else {
2137                         /* Insert before */
2138                         BUG_ON(newext->ee_block == nearex->ee_block);
2139                         ext_debug(inode, "insert %u:%llu:[%d]%d after: "
2140                                         "nearest %p\n",
2141                                         le32_to_cpu(newext->ee_block),
2142                                         ext4_ext_pblock(newext),
2143                                         ext4_ext_is_unwritten(newext),
2144                                         ext4_ext_get_actual_len(newext),
2145                                         nearex);
2146                 }
2147                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2148                 if (len > 0) {
2149                         ext_debug(inode, "insert %u:%llu:[%d]%d: "
2150                                         "move %d extents from 0x%p to 0x%p\n",
2151                                         le32_to_cpu(newext->ee_block),
2152                                         ext4_ext_pblock(newext),
2153                                         ext4_ext_is_unwritten(newext),
2154                                         ext4_ext_get_actual_len(newext),
2155                                         len, nearex, nearex + 1);
2156                         memmove(nearex + 1, nearex,
2157                                 len * sizeof(struct ext4_extent));
2158                 }
2159         }
2160
2161         le16_add_cpu(&eh->eh_entries, 1);
2162         path[depth].p_ext = nearex;
2163         nearex->ee_block = newext->ee_block;
2164         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2165         nearex->ee_len = newext->ee_len;
2166
2167 merge:
2168         /* try to merge extents */
2169         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2170                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2171
2172
2173         /* time to correct all indexes above */
2174         err = ext4_ext_correct_indexes(handle, inode, path);
2175         if (err)
2176                 goto cleanup;
2177
2178         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2179
2180 cleanup:
2181         ext4_free_ext_path(npath);
2182         return err;
2183 }
2184
2185 static int ext4_fill_es_cache_info(struct inode *inode,
2186                                    ext4_lblk_t block, ext4_lblk_t num,
2187                                    struct fiemap_extent_info *fieinfo)
2188 {
2189         ext4_lblk_t next, end = block + num - 1;
2190         struct extent_status es;
2191         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2192         unsigned int flags;
2193         int err;
2194
2195         while (block <= end) {
2196                 next = 0;
2197                 flags = 0;
2198                 if (!ext4_es_lookup_extent(inode, block, &next, &es))
2199                         break;
2200                 if (ext4_es_is_unwritten(&es))
2201                         flags |= FIEMAP_EXTENT_UNWRITTEN;
2202                 if (ext4_es_is_delayed(&es))
2203                         flags |= (FIEMAP_EXTENT_DELALLOC |
2204                                   FIEMAP_EXTENT_UNKNOWN);
2205                 if (ext4_es_is_hole(&es))
2206                         flags |= EXT4_FIEMAP_EXTENT_HOLE;
2207                 if (next == 0)
2208                         flags |= FIEMAP_EXTENT_LAST;
2209                 if (flags & (FIEMAP_EXTENT_DELALLOC|
2210                              EXT4_FIEMAP_EXTENT_HOLE))
2211                         es.es_pblk = 0;
2212                 else
2213                         es.es_pblk = ext4_es_pblock(&es);
2214                 err = fiemap_fill_next_extent(fieinfo,
2215                                 (__u64)es.es_lblk << blksize_bits,
2216                                 (__u64)es.es_pblk << blksize_bits,
2217                                 (__u64)es.es_len << blksize_bits,
2218                                 flags);
2219                 if (next == 0)
2220                         break;
2221                 block = next;
2222                 if (err < 0)
2223                         return err;
2224                 if (err == 1)
2225                         return 0;
2226         }
2227         return 0;
2228 }
2229
2230
2231 /*
2232  * ext4_ext_determine_hole - determine hole around given block
2233  * @inode:      inode we lookup in
2234  * @path:       path in extent tree to @lblk
2235  * @lblk:       pointer to logical block around which we want to determine hole
2236  *
2237  * Determine hole length (and start if easily possible) around given logical
2238  * block. We don't try too hard to find the beginning of the hole but @path
2239  * actually points to extent before @lblk, we provide it.
2240  *
2241  * The function returns the length of a hole starting at @lblk. We update @lblk
2242  * to the beginning of the hole if we managed to find it.
2243  */
2244 static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2245                                            struct ext4_ext_path *path,
2246                                            ext4_lblk_t *lblk)
2247 {
2248         int depth = ext_depth(inode);
2249         struct ext4_extent *ex;
2250         ext4_lblk_t len;
2251
2252         ex = path[depth].p_ext;
2253         if (ex == NULL) {
2254                 /* there is no extent yet, so gap is [0;-] */
2255                 *lblk = 0;
2256                 len = EXT_MAX_BLOCKS;
2257         } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2258                 len = le32_to_cpu(ex->ee_block) - *lblk;
2259         } else if (*lblk >= le32_to_cpu(ex->ee_block)
2260                         + ext4_ext_get_actual_len(ex)) {
2261                 ext4_lblk_t next;
2262
2263                 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2264                 next = ext4_ext_next_allocated_block(path);
2265                 BUG_ON(next == *lblk);
2266                 len = next - *lblk;
2267         } else {
2268                 BUG();
2269         }
2270         return len;
2271 }
2272
2273 /*
2274  * ext4_ext_put_gap_in_cache:
2275  * calculate boundaries of the gap that the requested block fits into
2276  * and cache this gap
2277  */
2278 static void
2279 ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2280                           ext4_lblk_t hole_len)
2281 {
2282         struct extent_status es;
2283
2284         ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
2285                                   hole_start + hole_len - 1, &es);
2286         if (es.es_len) {
2287                 /* There's delayed extent containing lblock? */
2288                 if (es.es_lblk <= hole_start)
2289                         return;
2290                 hole_len = min(es.es_lblk - hole_start, hole_len);
2291         }
2292         ext_debug(inode, " -> %u:%u\n", hole_start, hole_len);
2293         ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2294                               EXTENT_STATUS_HOLE);
2295 }
2296
2297 /*
2298  * ext4_ext_rm_idx:
2299  * removes index from the index block.
2300  */
2301 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2302                         struct ext4_ext_path *path, int depth)
2303 {
2304         int err;
2305         ext4_fsblk_t leaf;
2306
2307         /* free index block */
2308         depth--;
2309         path = path + depth;
2310         leaf = ext4_idx_pblock(path->p_idx);
2311         if (unlikely(path->p_hdr->eh_entries == 0)) {
2312                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2313                 return -EFSCORRUPTED;
2314         }
2315         err = ext4_ext_get_access(handle, inode, path);
2316         if (err)
2317                 return err;
2318
2319         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2320                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2321                 len *= sizeof(struct ext4_extent_idx);
2322                 memmove(path->p_idx, path->p_idx + 1, len);
2323         }
2324
2325         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2326         err = ext4_ext_dirty(handle, inode, path);
2327         if (err)
2328                 return err;
2329         ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
2330         trace_ext4_ext_rm_idx(inode, leaf);
2331
2332         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2333                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2334
2335         while (--depth >= 0) {
2336                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2337                         break;
2338                 path--;
2339                 err = ext4_ext_get_access(handle, inode, path);
2340                 if (err)
2341                         break;
2342                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2343                 err = ext4_ext_dirty(handle, inode, path);
2344                 if (err)
2345                         break;
2346         }
2347         return err;
2348 }
2349
2350 /*
2351  * ext4_ext_calc_credits_for_single_extent:
2352  * This routine returns max. credits that needed to insert an extent
2353  * to the extent tree.
2354  * When pass the actual path, the caller should calculate credits
2355  * under i_data_sem.
2356  */
2357 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2358                                                 struct ext4_ext_path *path)
2359 {
2360         if (path) {
2361                 int depth = ext_depth(inode);
2362                 int ret = 0;
2363
2364                 /* probably there is space in leaf? */
2365                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2366                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2367
2368                         /*
2369                          *  There are some space in the leaf tree, no
2370                          *  need to account for leaf block credit
2371                          *
2372                          *  bitmaps and block group descriptor blocks
2373                          *  and other metadata blocks still need to be
2374                          *  accounted.
2375                          */
2376                         /* 1 bitmap, 1 block group descriptor */
2377                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2378                         return ret;
2379                 }
2380         }
2381
2382         return ext4_chunk_trans_blocks(inode, nrblocks);
2383 }
2384
2385 /*
2386  * How many index/leaf blocks need to change/allocate to add @extents extents?
2387  *
2388  * If we add a single extent, then in the worse case, each tree level
2389  * index/leaf need to be changed in case of the tree split.
2390  *
2391  * If more extents are inserted, they could cause the whole tree split more
2392  * than once, but this is really rare.
2393  */
2394 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2395 {
2396         int index;
2397         int depth;
2398
2399         /* If we are converting the inline data, only one is needed here. */
2400         if (ext4_has_inline_data(inode))
2401                 return 1;
2402
2403         depth = ext_depth(inode);
2404
2405         if (extents <= 1)
2406                 index = depth * 2;
2407         else
2408                 index = depth * 3;
2409
2410         return index;
2411 }
2412
2413 static inline int get_default_free_blocks_flags(struct inode *inode)
2414 {
2415         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2416             ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2417                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2418         else if (ext4_should_journal_data(inode))
2419                 return EXT4_FREE_BLOCKS_FORGET;
2420         return 0;
2421 }
2422
2423 /*
2424  * ext4_rereserve_cluster - increment the reserved cluster count when
2425  *                          freeing a cluster with a pending reservation
2426  *
2427  * @inode - file containing the cluster
2428  * @lblk - logical block in cluster to be reserved
2429  *
2430  * Increments the reserved cluster count and adjusts quota in a bigalloc
2431  * file system when freeing a partial cluster containing at least one
2432  * delayed and unwritten block.  A partial cluster meeting that
2433  * requirement will have a pending reservation.  If so, the
2434  * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2435  * defer reserved and allocated space accounting to a subsequent call
2436  * to this function.
2437  */
2438 static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2439 {
2440         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2441         struct ext4_inode_info *ei = EXT4_I(inode);
2442
2443         dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2444
2445         spin_lock(&ei->i_block_reservation_lock);
2446         ei->i_reserved_data_blocks++;
2447         percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2448         spin_unlock(&ei->i_block_reservation_lock);
2449
2450         percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2451         ext4_remove_pending(inode, lblk);
2452 }
2453
2454 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2455                               struct ext4_extent *ex,
2456                               struct partial_cluster *partial,
2457                               ext4_lblk_t from, ext4_lblk_t to)
2458 {
2459         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2460         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2461         ext4_fsblk_t last_pblk, pblk;
2462         ext4_lblk_t num;
2463         int flags;
2464
2465         /* only extent tail removal is allowed */
2466         if (from < le32_to_cpu(ex->ee_block) ||
2467             to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2468                 ext4_error(sbi->s_sb,
2469                            "strange request: removal(2) %u-%u from %u:%u",
2470                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2471                 return 0;
2472         }
2473
2474 #ifdef EXTENTS_STATS
2475         spin_lock(&sbi->s_ext_stats_lock);
2476         sbi->s_ext_blocks += ee_len;
2477         sbi->s_ext_extents++;
2478         if (ee_len < sbi->s_ext_min)
2479                 sbi->s_ext_min = ee_len;
2480         if (ee_len > sbi->s_ext_max)
2481                 sbi->s_ext_max = ee_len;
2482         if (ext_depth(inode) > sbi->s_depth_max)
2483                 sbi->s_depth_max = ext_depth(inode);
2484         spin_unlock(&sbi->s_ext_stats_lock);
2485 #endif
2486
2487         trace_ext4_remove_blocks(inode, ex, from, to, partial);
2488
2489         /*
2490          * if we have a partial cluster, and it's different from the
2491          * cluster of the last block in the extent, we free it
2492          */
2493         last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2494
2495         if (partial->state != initial &&
2496             partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2497                 if (partial->state == tofree) {
2498                         flags = get_default_free_blocks_flags(inode);
2499                         if (ext4_is_pending(inode, partial->lblk))
2500                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2501                         ext4_free_blocks(handle, inode, NULL,
2502                                          EXT4_C2B(sbi, partial->pclu),
2503                                          sbi->s_cluster_ratio, flags);
2504                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2505                                 ext4_rereserve_cluster(inode, partial->lblk);
2506                 }
2507                 partial->state = initial;
2508         }
2509
2510         num = le32_to_cpu(ex->ee_block) + ee_len - from;
2511         pblk = ext4_ext_pblock(ex) + ee_len - num;
2512
2513         /*
2514          * We free the partial cluster at the end of the extent (if any),
2515          * unless the cluster is used by another extent (partial_cluster
2516          * state is nofree).  If a partial cluster exists here, it must be
2517          * shared with the last block in the extent.
2518          */
2519         flags = get_default_free_blocks_flags(inode);
2520
2521         /* partial, left end cluster aligned, right end unaligned */
2522         if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2523             (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2524             (partial->state != nofree)) {
2525                 if (ext4_is_pending(inode, to))
2526                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2527                 ext4_free_blocks(handle, inode, NULL,
2528                                  EXT4_PBLK_CMASK(sbi, last_pblk),
2529                                  sbi->s_cluster_ratio, flags);
2530                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2531                         ext4_rereserve_cluster(inode, to);
2532                 partial->state = initial;
2533                 flags = get_default_free_blocks_flags(inode);
2534         }
2535
2536         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2537
2538         /*
2539          * For bigalloc file systems, we never free a partial cluster
2540          * at the beginning of the extent.  Instead, we check to see if we
2541          * need to free it on a subsequent call to ext4_remove_blocks,
2542          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2543          */
2544         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2545         ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2546
2547         /* reset the partial cluster if we've freed past it */
2548         if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2549                 partial->state = initial;
2550
2551         /*
2552          * If we've freed the entire extent but the beginning is not left
2553          * cluster aligned and is not marked as ineligible for freeing we
2554          * record the partial cluster at the beginning of the extent.  It
2555          * wasn't freed by the preceding ext4_free_blocks() call, and we
2556          * need to look farther to the left to determine if it's to be freed
2557          * (not shared with another extent). Else, reset the partial
2558          * cluster - we're either  done freeing or the beginning of the
2559          * extent is left cluster aligned.
2560          */
2561         if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2562                 if (partial->state == initial) {
2563                         partial->pclu = EXT4_B2C(sbi, pblk);
2564                         partial->lblk = from;
2565                         partial->state = tofree;
2566                 }
2567         } else {
2568                 partial->state = initial;
2569         }
2570
2571         return 0;
2572 }
2573
2574 /*
2575  * ext4_ext_rm_leaf() Removes the extents associated with the
2576  * blocks appearing between "start" and "end".  Both "start"
2577  * and "end" must appear in the same extent or EIO is returned.
2578  *
2579  * @handle: The journal handle
2580  * @inode:  The files inode
2581  * @path:   The path to the leaf
2582  * @partial_cluster: The cluster which we'll have to free if all extents
2583  *                   has been released from it.  However, if this value is
2584  *                   negative, it's a cluster just to the right of the
2585  *                   punched region and it must not be freed.
2586  * @start:  The first block to remove
2587  * @end:   The last block to remove
2588  */
2589 static int
2590 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2591                  struct ext4_ext_path *path,
2592                  struct partial_cluster *partial,
2593                  ext4_lblk_t start, ext4_lblk_t end)
2594 {
2595         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2596         int err = 0, correct_index = 0;
2597         int depth = ext_depth(inode), credits, revoke_credits;
2598         struct ext4_extent_header *eh;
2599         ext4_lblk_t a, b;
2600         unsigned num;
2601         ext4_lblk_t ex_ee_block;
2602         unsigned short ex_ee_len;
2603         unsigned unwritten = 0;
2604         struct ext4_extent *ex;
2605         ext4_fsblk_t pblk;
2606
2607         /* the header must be checked already in ext4_ext_remove_space() */
2608         ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
2609         if (!path[depth].p_hdr)
2610                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2611         eh = path[depth].p_hdr;
2612         if (unlikely(path[depth].p_hdr == NULL)) {
2613                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2614                 return -EFSCORRUPTED;
2615         }
2616         /* find where to start removing */
2617         ex = path[depth].p_ext;
2618         if (!ex)
2619                 ex = EXT_LAST_EXTENT(eh);
2620
2621         ex_ee_block = le32_to_cpu(ex->ee_block);
2622         ex_ee_len = ext4_ext_get_actual_len(ex);
2623
2624         trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2625
2626         while (ex >= EXT_FIRST_EXTENT(eh) &&
2627                         ex_ee_block + ex_ee_len > start) {
2628
2629                 if (ext4_ext_is_unwritten(ex))
2630                         unwritten = 1;
2631                 else
2632                         unwritten = 0;
2633
2634                 ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
2635                           unwritten, ex_ee_len);
2636                 path[depth].p_ext = ex;
2637
2638                 a = ex_ee_block > start ? ex_ee_block : start;
2639                 b = ex_ee_block+ex_ee_len - 1 < end ?
2640                         ex_ee_block+ex_ee_len - 1 : end;
2641
2642                 ext_debug(inode, "  border %u:%u\n", a, b);
2643
2644                 /* If this extent is beyond the end of the hole, skip it */
2645                 if (end < ex_ee_block) {
2646                         /*
2647                          * We're going to skip this extent and move to another,
2648                          * so note that its first cluster is in use to avoid
2649                          * freeing it when removing blocks.  Eventually, the
2650                          * right edge of the truncated/punched region will
2651                          * be just to the left.
2652                          */
2653                         if (sbi->s_cluster_ratio > 1) {
2654                                 pblk = ext4_ext_pblock(ex);
2655                                 partial->pclu = EXT4_B2C(sbi, pblk);
2656                                 partial->state = nofree;
2657                         }
2658                         ex--;
2659                         ex_ee_block = le32_to_cpu(ex->ee_block);
2660                         ex_ee_len = ext4_ext_get_actual_len(ex);
2661                         continue;
2662                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2663                         EXT4_ERROR_INODE(inode,
2664                                          "can not handle truncate %u:%u "
2665                                          "on extent %u:%u",
2666                                          start, end, ex_ee_block,
2667                                          ex_ee_block + ex_ee_len - 1);
2668                         err = -EFSCORRUPTED;
2669                         goto out;
2670                 } else if (a != ex_ee_block) {
2671                         /* remove tail of the extent */
2672                         num = a - ex_ee_block;
2673                 } else {
2674                         /* remove whole extent: excellent! */
2675                         num = 0;
2676                 }
2677                 /*
2678                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2679                  * descriptor) for each block group; assume two block
2680                  * groups plus ex_ee_len/blocks_per_block_group for
2681                  * the worst case
2682                  */
2683                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2684                 if (ex == EXT_FIRST_EXTENT(eh)) {
2685                         correct_index = 1;
2686                         credits += (ext_depth(inode)) + 1;
2687                 }
2688                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2689                 /*
2690                  * We may end up freeing some index blocks and data from the
2691                  * punched range. Note that partial clusters are accounted for
2692                  * by ext4_free_data_revoke_credits().
2693                  */
2694                 revoke_credits =
2695                         ext4_free_metadata_revoke_credits(inode->i_sb,
2696                                                           ext_depth(inode)) +
2697                         ext4_free_data_revoke_credits(inode, b - a + 1);
2698
2699                 err = ext4_datasem_ensure_credits(handle, inode, credits,
2700                                                   credits, revoke_credits);
2701                 if (err) {
2702                         if (err > 0)
2703                                 err = -EAGAIN;
2704                         goto out;
2705                 }
2706
2707                 err = ext4_ext_get_access(handle, inode, path + depth);
2708                 if (err)
2709                         goto out;
2710
2711                 err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2712                 if (err)
2713                         goto out;
2714
2715                 if (num == 0)
2716                         /* this extent is removed; mark slot entirely unused */
2717                         ext4_ext_store_pblock(ex, 0);
2718
2719                 ex->ee_len = cpu_to_le16(num);
2720                 /*
2721                  * Do not mark unwritten if all the blocks in the
2722                  * extent have been removed.
2723                  */
2724                 if (unwritten && num)
2725                         ext4_ext_mark_unwritten(ex);
2726                 /*
2727                  * If the extent was completely released,
2728                  * we need to remove it from the leaf
2729                  */
2730                 if (num == 0) {
2731                         if (end != EXT_MAX_BLOCKS - 1) {
2732                                 /*
2733                                  * For hole punching, we need to scoot all the
2734                                  * extents up when an extent is removed so that
2735                                  * we dont have blank extents in the middle
2736                                  */
2737                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2738                                         sizeof(struct ext4_extent));
2739
2740                                 /* Now get rid of the one at the end */
2741                                 memset(EXT_LAST_EXTENT(eh), 0,
2742                                         sizeof(struct ext4_extent));
2743                         }
2744                         le16_add_cpu(&eh->eh_entries, -1);
2745                 }
2746
2747                 err = ext4_ext_dirty(handle, inode, path + depth);
2748                 if (err)
2749                         goto out;
2750
2751                 ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
2752                                 ext4_ext_pblock(ex));
2753                 ex--;
2754                 ex_ee_block = le32_to_cpu(ex->ee_block);
2755                 ex_ee_len = ext4_ext_get_actual_len(ex);
2756         }
2757
2758         if (correct_index && eh->eh_entries)
2759                 err = ext4_ext_correct_indexes(handle, inode, path);
2760
2761         /*
2762          * If there's a partial cluster and at least one extent remains in
2763          * the leaf, free the partial cluster if it isn't shared with the
2764          * current extent.  If it is shared with the current extent
2765          * we reset the partial cluster because we've reached the start of the
2766          * truncated/punched region and we're done removing blocks.
2767          */
2768         if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2769                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2770                 if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2771                         int flags = get_default_free_blocks_flags(inode);
2772
2773                         if (ext4_is_pending(inode, partial->lblk))
2774                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2775                         ext4_free_blocks(handle, inode, NULL,
2776                                          EXT4_C2B(sbi, partial->pclu),
2777                                          sbi->s_cluster_ratio, flags);
2778                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2779                                 ext4_rereserve_cluster(inode, partial->lblk);
2780                 }
2781                 partial->state = initial;
2782         }
2783
2784         /* if this leaf is free, then we should
2785          * remove it from index block above */
2786         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2787                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2788
2789 out:
2790         return err;
2791 }
2792
2793 /*
2794  * ext4_ext_more_to_rm:
2795  * returns 1 if current index has to be freed (even partial)
2796  */
2797 static int
2798 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2799 {
2800         BUG_ON(path->p_idx == NULL);
2801
2802         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2803                 return 0;
2804
2805         /*
2806          * if truncate on deeper level happened, it wasn't partial,
2807          * so we have to consider current index for truncation
2808          */
2809         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2810                 return 0;
2811         return 1;
2812 }
2813
2814 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2815                           ext4_lblk_t end)
2816 {
2817         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2818         int depth = ext_depth(inode);
2819         struct ext4_ext_path *path = NULL;
2820         struct partial_cluster partial;
2821         handle_t *handle;
2822         int i = 0, err = 0;
2823
2824         partial.pclu = 0;
2825         partial.lblk = 0;
2826         partial.state = initial;
2827
2828         ext_debug(inode, "truncate since %u to %u\n", start, end);
2829
2830         /* probably first extent we're gonna free will be last in block */
2831         handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2832                         depth + 1,
2833                         ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2834         if (IS_ERR(handle))
2835                 return PTR_ERR(handle);
2836
2837 again:
2838         trace_ext4_ext_remove_space(inode, start, end, depth);
2839
2840         /*
2841          * Check if we are removing extents inside the extent tree. If that
2842          * is the case, we are going to punch a hole inside the extent tree
2843          * so we have to check whether we need to split the extent covering
2844          * the last block to remove so we can easily remove the part of it
2845          * in ext4_ext_rm_leaf().
2846          */
2847         if (end < EXT_MAX_BLOCKS - 1) {
2848                 struct ext4_extent *ex;
2849                 ext4_lblk_t ee_block, ex_end, lblk;
2850                 ext4_fsblk_t pblk;
2851
2852                 /* find extent for or closest extent to this block */
2853                 path = ext4_find_extent(inode, end, NULL,
2854                                         EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
2855                 if (IS_ERR(path)) {
2856                         ext4_journal_stop(handle);
2857                         return PTR_ERR(path);
2858                 }
2859                 depth = ext_depth(inode);
2860                 /* Leaf not may not exist only if inode has no blocks at all */
2861                 ex = path[depth].p_ext;
2862                 if (!ex) {
2863                         if (depth) {
2864                                 EXT4_ERROR_INODE(inode,
2865                                                  "path[%d].p_hdr == NULL",
2866                                                  depth);
2867                                 err = -EFSCORRUPTED;
2868                         }
2869                         goto out;
2870                 }
2871
2872                 ee_block = le32_to_cpu(ex->ee_block);
2873                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2874
2875                 /*
2876                  * See if the last block is inside the extent, if so split
2877                  * the extent at 'end' block so we can easily remove the
2878                  * tail of the first part of the split extent in
2879                  * ext4_ext_rm_leaf().
2880                  */
2881                 if (end >= ee_block && end < ex_end) {
2882
2883                         /*
2884                          * If we're going to split the extent, note that
2885                          * the cluster containing the block after 'end' is
2886                          * in use to avoid freeing it when removing blocks.
2887                          */
2888                         if (sbi->s_cluster_ratio > 1) {
2889                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
2890                                 partial.pclu = EXT4_B2C(sbi, pblk);
2891                                 partial.state = nofree;
2892                         }
2893
2894                         /*
2895                          * Split the extent in two so that 'end' is the last
2896                          * block in the first new extent. Also we should not
2897                          * fail removing space due to ENOSPC so try to use
2898                          * reserved block if that happens.
2899                          */
2900                         err = ext4_force_split_extent_at(handle, inode, &path,
2901                                                          end + 1, 1);
2902                         if (err < 0)
2903                                 goto out;
2904
2905                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
2906                            partial.state == initial) {
2907                         /*
2908                          * If we're punching, there's an extent to the right.
2909                          * If the partial cluster hasn't been set, set it to
2910                          * that extent's first cluster and its state to nofree
2911                          * so it won't be freed should it contain blocks to be
2912                          * removed. If it's already set (tofree/nofree), we're
2913                          * retrying and keep the original partial cluster info
2914                          * so a cluster marked tofree as a result of earlier
2915                          * extent removal is not lost.
2916                          */
2917                         lblk = ex_end + 1;
2918                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2919                                                     NULL);
2920                         if (err < 0)
2921                                 goto out;
2922                         if (pblk) {
2923                                 partial.pclu = EXT4_B2C(sbi, pblk);
2924                                 partial.state = nofree;
2925                         }
2926                 }
2927         }
2928         /*
2929          * We start scanning from right side, freeing all the blocks
2930          * after i_size and walking into the tree depth-wise.
2931          */
2932         depth = ext_depth(inode);
2933         if (path) {
2934                 int k = i = depth;
2935                 while (--k > 0)
2936                         path[k].p_block =
2937                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2938         } else {
2939                 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
2940                                GFP_NOFS | __GFP_NOFAIL);
2941                 if (path == NULL) {
2942                         ext4_journal_stop(handle);
2943                         return -ENOMEM;
2944                 }
2945                 path[0].p_maxdepth = path[0].p_depth = depth;
2946                 path[0].p_hdr = ext_inode_hdr(inode);
2947                 i = 0;
2948
2949                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2950                         err = -EFSCORRUPTED;
2951                         goto out;
2952                 }
2953         }
2954         err = 0;
2955
2956         while (i >= 0 && err == 0) {
2957                 if (i == depth) {
2958                         /* this is leaf block */
2959                         err = ext4_ext_rm_leaf(handle, inode, path,
2960                                                &partial, start, end);
2961                         /* root level has p_bh == NULL, brelse() eats this */
2962                         brelse(path[i].p_bh);
2963                         path[i].p_bh = NULL;
2964                         i--;
2965                         continue;
2966                 }
2967
2968                 /* this is index block */
2969                 if (!path[i].p_hdr) {
2970                         ext_debug(inode, "initialize header\n");
2971                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2972                 }
2973
2974                 if (!path[i].p_idx) {
2975                         /* this level hasn't been touched yet */
2976                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2977                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2978                         ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
2979                                   path[i].p_hdr,
2980                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2981                 } else {
2982                         /* we were already here, see at next index */
2983                         path[i].p_idx--;
2984                 }
2985
2986                 ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
2987                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2988                                 path[i].p_idx);
2989                 if (ext4_ext_more_to_rm(path + i)) {
2990                         struct buffer_head *bh;
2991                         /* go to the next level */
2992                         ext_debug(inode, "move to level %d (block %llu)\n",
2993                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2994                         memset(path + i + 1, 0, sizeof(*path));
2995                         bh = read_extent_tree_block(inode, path[i].p_idx,
2996                                                     depth - i - 1,
2997                                                     EXT4_EX_NOCACHE);
2998                         if (IS_ERR(bh)) {
2999                                 /* should we reset i_size? */
3000                                 err = PTR_ERR(bh);
3001                                 break;
3002                         }
3003                         /* Yield here to deal with large extent trees.
3004                          * Should be a no-op if we did IO above. */
3005                         cond_resched();
3006                         if (WARN_ON(i + 1 > depth)) {
3007                                 err = -EFSCORRUPTED;
3008                                 break;
3009                         }
3010                         path[i + 1].p_bh = bh;
3011
3012                         /* save actual number of indexes since this
3013                          * number is changed at the next iteration */
3014                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3015                         i++;
3016                 } else {
3017                         /* we finished processing this index, go up */
3018                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3019                                 /* index is empty, remove it;
3020                                  * handle must be already prepared by the
3021                                  * truncatei_leaf() */
3022                                 err = ext4_ext_rm_idx(handle, inode, path, i);
3023                         }
3024                         /* root level has p_bh == NULL, brelse() eats this */
3025                         brelse(path[i].p_bh);
3026                         path[i].p_bh = NULL;
3027                         i--;
3028                         ext_debug(inode, "return to level %d\n", i);
3029                 }
3030         }
3031
3032         trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3033                                          path->p_hdr->eh_entries);
3034
3035         /*
3036          * if there's a partial cluster and we have removed the first extent
3037          * in the file, then we also free the partial cluster, if any
3038          */
3039         if (partial.state == tofree && err == 0) {
3040                 int flags = get_default_free_blocks_flags(inode);
3041
3042                 if (ext4_is_pending(inode, partial.lblk))
3043                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3044                 ext4_free_blocks(handle, inode, NULL,
3045                                  EXT4_C2B(sbi, partial.pclu),
3046                                  sbi->s_cluster_ratio, flags);
3047                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3048                         ext4_rereserve_cluster(inode, partial.lblk);
3049                 partial.state = initial;
3050         }
3051
3052         /* TODO: flexible tree reduction should be here */
3053         if (path->p_hdr->eh_entries == 0) {
3054                 /*
3055                  * truncate to zero freed all the tree,
3056                  * so we need to correct eh_depth
3057                  */
3058                 err = ext4_ext_get_access(handle, inode, path);
3059                 if (err == 0) {
3060                         ext_inode_hdr(inode)->eh_depth = 0;
3061                         ext_inode_hdr(inode)->eh_max =
3062                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3063                         err = ext4_ext_dirty(handle, inode, path);
3064                 }
3065         }
3066 out:
3067         ext4_free_ext_path(path);
3068         path = NULL;
3069         if (err == -EAGAIN)
3070                 goto again;
3071         ext4_journal_stop(handle);
3072
3073         return err;
3074 }
3075
3076 /*
3077  * called at mount time
3078  */
3079 void ext4_ext_init(struct super_block *sb)
3080 {
3081         /*
3082          * possible initialization would be here
3083          */
3084
3085         if (ext4_has_feature_extents(sb)) {
3086 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3087                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3088 #ifdef AGGRESSIVE_TEST
3089                        ", aggressive tests"
3090 #endif
3091 #ifdef CHECK_BINSEARCH
3092                        ", check binsearch"
3093 #endif
3094 #ifdef EXTENTS_STATS
3095                        ", stats"
3096 #endif
3097                        "\n");
3098 #endif
3099 #ifdef EXTENTS_STATS
3100                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3101                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3102                 EXT4_SB(sb)->s_ext_max = 0;
3103 #endif
3104         }
3105 }
3106
3107 /*
3108  * called at umount time
3109  */
3110 void ext4_ext_release(struct super_block *sb)
3111 {
3112         if (!ext4_has_feature_extents(sb))
3113                 return;
3114
3115 #ifdef EXTENTS_STATS
3116         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3117                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3118                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3119                         sbi->s_ext_blocks, sbi->s_ext_extents,
3120                         sbi->s_ext_blocks / sbi->s_ext_extents);
3121                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3122                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3123         }
3124 #endif
3125 }
3126
3127 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3128 {
3129         ext4_lblk_t  ee_block;
3130         ext4_fsblk_t ee_pblock;
3131         unsigned int ee_len;
3132
3133         ee_block  = le32_to_cpu(ex->ee_block);
3134         ee_len    = ext4_ext_get_actual_len(ex);
3135         ee_pblock = ext4_ext_pblock(ex);
3136
3137         if (ee_len == 0)
3138                 return 0;
3139
3140         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3141                                      EXTENT_STATUS_WRITTEN);
3142 }
3143
3144 /* FIXME!! we need to try to merge to left or right after zero-out  */
3145 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3146 {
3147         ext4_fsblk_t ee_pblock;
3148         unsigned int ee_len;
3149
3150         ee_len    = ext4_ext_get_actual_len(ex);
3151         ee_pblock = ext4_ext_pblock(ex);
3152         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3153                                   ee_len);
3154 }
3155
3156 /*
3157  * ext4_split_extent_at() splits an extent at given block.
3158  *
3159  * @handle: the journal handle
3160  * @inode: the file inode
3161  * @path: the path to the extent
3162  * @split: the logical block where the extent is splitted.
3163  * @split_flags: indicates if the extent could be zeroout if split fails, and
3164  *               the states(init or unwritten) of new extents.
3165  * @flags: flags used to insert new extent to extent tree.
3166  *
3167  *
3168  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3169  * of which are determined by split_flag.
3170  *
3171  * There are two cases:
3172  *  a> the extent are splitted into two extent.
3173  *  b> split is not needed, and just mark the extent.
3174  *
3175  * return 0 on success.
3176  */
3177 static int ext4_split_extent_at(handle_t *handle,
3178                              struct inode *inode,
3179                              struct ext4_ext_path **ppath,
3180                              ext4_lblk_t split,
3181                              int split_flag,
3182                              int flags)
3183 {
3184         struct ext4_ext_path *path = *ppath;
3185         ext4_fsblk_t newblock;
3186         ext4_lblk_t ee_block;
3187         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3188         struct ext4_extent *ex2 = NULL;
3189         unsigned int ee_len, depth;
3190         int err = 0;
3191
3192         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3193                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3194
3195         ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
3196
3197         ext4_ext_show_leaf(inode, path);
3198
3199         depth = ext_depth(inode);
3200         ex = path[depth].p_ext;
3201         ee_block = le32_to_cpu(ex->ee_block);
3202         ee_len = ext4_ext_get_actual_len(ex);
3203         newblock = split - ee_block + ext4_ext_pblock(ex);
3204
3205         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3206         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3207                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3208                              EXT4_EXT_MARK_UNWRIT1 |
3209                              EXT4_EXT_MARK_UNWRIT2));
3210
3211         err = ext4_ext_get_access(handle, inode, path + depth);
3212         if (err)
3213                 goto out;
3214
3215         if (split == ee_block) {
3216                 /*
3217                  * case b: block @split is the block that the extent begins with
3218                  * then we just change the state of the extent, and splitting
3219                  * is not needed.
3220                  */
3221                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3222                         ext4_ext_mark_unwritten(ex);
3223                 else
3224                         ext4_ext_mark_initialized(ex);
3225
3226                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3227                         ext4_ext_try_to_merge(handle, inode, path, ex);
3228
3229                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3230                 goto out;
3231         }
3232
3233         /* case a */
3234         memcpy(&orig_ex, ex, sizeof(orig_ex));
3235         ex->ee_len = cpu_to_le16(split - ee_block);
3236         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3237                 ext4_ext_mark_unwritten(ex);
3238
3239         /*
3240          * path may lead to new leaf, not to original leaf any more
3241          * after ext4_ext_insert_extent() returns,
3242          */
3243         err = ext4_ext_dirty(handle, inode, path + depth);
3244         if (err)
3245                 goto fix_extent_len;
3246
3247         ex2 = &newex;
3248         ex2->ee_block = cpu_to_le32(split);
3249         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3250         ext4_ext_store_pblock(ex2, newblock);
3251         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3252                 ext4_ext_mark_unwritten(ex2);
3253
3254         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3255         if (err != -ENOSPC && err != -EDQUOT)
3256                 goto out;
3257
3258         if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
3259                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3260                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3261                                 err = ext4_ext_zeroout(inode, ex2);
3262                                 zero_ex.ee_block = ex2->ee_block;
3263                                 zero_ex.ee_len = cpu_to_le16(
3264                                                 ext4_ext_get_actual_len(ex2));
3265                                 ext4_ext_store_pblock(&zero_ex,
3266                                                       ext4_ext_pblock(ex2));
3267                         } else {
3268                                 err = ext4_ext_zeroout(inode, ex);
3269                                 zero_ex.ee_block = ex->ee_block;
3270                                 zero_ex.ee_len = cpu_to_le16(
3271                                                 ext4_ext_get_actual_len(ex));
3272                                 ext4_ext_store_pblock(&zero_ex,
3273                                                       ext4_ext_pblock(ex));
3274                         }
3275                 } else {
3276                         err = ext4_ext_zeroout(inode, &orig_ex);
3277                         zero_ex.ee_block = orig_ex.ee_block;
3278                         zero_ex.ee_len = cpu_to_le16(
3279                                                 ext4_ext_get_actual_len(&orig_ex));
3280                         ext4_ext_store_pblock(&zero_ex,
3281                                               ext4_ext_pblock(&orig_ex));
3282                 }
3283
3284                 if (!err) {
3285                         /* update the extent length and mark as initialized */
3286                         ex->ee_len = cpu_to_le16(ee_len);
3287                         ext4_ext_try_to_merge(handle, inode, path, ex);
3288                         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3289                         if (!err)
3290                                 /* update extent status tree */
3291                                 err = ext4_zeroout_es(inode, &zero_ex);
3292                         /* If we failed at this point, we don't know in which
3293                          * state the extent tree exactly is so don't try to fix
3294                          * length of the original extent as it may do even more
3295                          * damage.
3296                          */
3297                         goto out;
3298                 }
3299         }
3300
3301 fix_extent_len:
3302         ex->ee_len = orig_ex.ee_len;
3303         /*
3304          * Ignore ext4_ext_dirty return value since we are already in error path
3305          * and err is a non-zero error code.
3306          */
3307         ext4_ext_dirty(handle, inode, path + path->p_depth);
3308         return err;
3309 out:
3310         ext4_ext_show_leaf(inode, path);
3311         return err;
3312 }
3313
3314 /*
3315  * ext4_split_extents() splits an extent and mark extent which is covered
3316  * by @map as split_flags indicates
3317  *
3318  * It may result in splitting the extent into multiple extents (up to three)
3319  * There are three possibilities:
3320  *   a> There is no split required
3321  *   b> Splits in two extents: Split is happening at either end of the extent
3322  *   c> Splits in three extents: Somone is splitting in middle of the extent
3323  *
3324  */
3325 static int ext4_split_extent(handle_t *handle,
3326                               struct inode *inode,
3327                               struct ext4_ext_path **ppath,
3328                               struct ext4_map_blocks *map,
3329                               int split_flag,
3330                               int flags)
3331 {
3332         struct ext4_ext_path *path = *ppath;
3333         ext4_lblk_t ee_block;
3334         struct ext4_extent *ex;
3335         unsigned int ee_len, depth;
3336         int err = 0;
3337         int unwritten;
3338         int split_flag1, flags1;
3339         int allocated = map->m_len;
3340
3341         depth = ext_depth(inode);
3342         ex = path[depth].p_ext;
3343         ee_block = le32_to_cpu(ex->ee_block);
3344         ee_len = ext4_ext_get_actual_len(ex);
3345         unwritten = ext4_ext_is_unwritten(ex);
3346
3347         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3348                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3349                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3350                 if (unwritten)
3351                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3352                                        EXT4_EXT_MARK_UNWRIT2;
3353                 if (split_flag & EXT4_EXT_DATA_VALID2)
3354                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3355                 err = ext4_split_extent_at(handle, inode, ppath,
3356                                 map->m_lblk + map->m_len, split_flag1, flags1);
3357                 if (err)
3358                         goto out;
3359         } else {
3360                 allocated = ee_len - (map->m_lblk - ee_block);
3361         }
3362         /*
3363          * Update path is required because previous ext4_split_extent_at() may
3364          * result in split of original leaf or extent zeroout.
3365          */
3366         path = ext4_find_extent(inode, map->m_lblk, ppath, flags);
3367         if (IS_ERR(path))
3368                 return PTR_ERR(path);
3369         depth = ext_depth(inode);
3370         ex = path[depth].p_ext;
3371         if (!ex) {
3372                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3373                                  (unsigned long) map->m_lblk);
3374                 return -EFSCORRUPTED;
3375         }
3376         unwritten = ext4_ext_is_unwritten(ex);
3377
3378         if (map->m_lblk >= ee_block) {
3379                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3380                 if (unwritten) {
3381                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3382                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3383                                                      EXT4_EXT_MARK_UNWRIT2);
3384                 }
3385                 err = ext4_split_extent_at(handle, inode, ppath,
3386                                 map->m_lblk, split_flag1, flags);
3387                 if (err)
3388                         goto out;
3389         }
3390
3391         ext4_ext_show_leaf(inode, path);
3392 out:
3393         return err ? err : allocated;
3394 }
3395
3396 /*
3397  * This function is called by ext4_ext_map_blocks() if someone tries to write
3398  * to an unwritten extent. It may result in splitting the unwritten
3399  * extent into multiple extents (up to three - one initialized and two
3400  * unwritten).
3401  * There are three possibilities:
3402  *   a> There is no split required: Entire extent should be initialized
3403  *   b> Splits in two extents: Write is happening at either end of the extent
3404  *   c> Splits in three extents: Somone is writing in middle of the extent
3405  *
3406  * Pre-conditions:
3407  *  - The extent pointed to by 'path' is unwritten.
3408  *  - The extent pointed to by 'path' contains a superset
3409  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3410  *
3411  * Post-conditions on success:
3412  *  - the returned value is the number of blocks beyond map->l_lblk
3413  *    that are allocated and initialized.
3414  *    It is guaranteed to be >= map->m_len.
3415  */
3416 static int ext4_ext_convert_to_initialized(handle_t *handle,
3417                                            struct inode *inode,
3418                                            struct ext4_map_blocks *map,
3419                                            struct ext4_ext_path **ppath,
3420                                            int flags)
3421 {
3422         struct ext4_ext_path *path = *ppath;
3423         struct ext4_sb_info *sbi;
3424         struct ext4_extent_header *eh;
3425         struct ext4_map_blocks split_map;
3426         struct ext4_extent zero_ex1, zero_ex2;
3427         struct ext4_extent *ex, *abut_ex;
3428         ext4_lblk_t ee_block, eof_block;
3429         unsigned int ee_len, depth, map_len = map->m_len;
3430         int allocated = 0, max_zeroout = 0;
3431         int err = 0;
3432         int split_flag = EXT4_EXT_DATA_VALID2;
3433
3434         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3435                   (unsigned long long)map->m_lblk, map_len);
3436
3437         sbi = EXT4_SB(inode->i_sb);
3438         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3439                         >> inode->i_sb->s_blocksize_bits;
3440         if (eof_block < map->m_lblk + map_len)
3441                 eof_block = map->m_lblk + map_len;
3442
3443         depth = ext_depth(inode);
3444         eh = path[depth].p_hdr;
3445         ex = path[depth].p_ext;
3446         ee_block = le32_to_cpu(ex->ee_block);
3447         ee_len = ext4_ext_get_actual_len(ex);
3448         zero_ex1.ee_len = 0;
3449         zero_ex2.ee_len = 0;
3450
3451         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3452
3453         /* Pre-conditions */
3454         BUG_ON(!ext4_ext_is_unwritten(ex));
3455         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3456
3457         /*
3458          * Attempt to transfer newly initialized blocks from the currently
3459          * unwritten extent to its neighbor. This is much cheaper
3460          * than an insertion followed by a merge as those involve costly
3461          * memmove() calls. Transferring to the left is the common case in
3462          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3463          * followed by append writes.
3464          *
3465          * Limitations of the current logic:
3466          *  - L1: we do not deal with writes covering the whole extent.
3467          *    This would require removing the extent if the transfer
3468          *    is possible.
3469          *  - L2: we only attempt to merge with an extent stored in the
3470          *    same extent tree node.
3471          */
3472         if ((map->m_lblk == ee_block) &&
3473                 /* See if we can merge left */
3474                 (map_len < ee_len) &&           /*L1*/
3475                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3476                 ext4_lblk_t prev_lblk;
3477                 ext4_fsblk_t prev_pblk, ee_pblk;
3478                 unsigned int prev_len;
3479
3480                 abut_ex = ex - 1;
3481                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3482                 prev_len = ext4_ext_get_actual_len(abut_ex);
3483                 prev_pblk = ext4_ext_pblock(abut_ex);
3484                 ee_pblk = ext4_ext_pblock(ex);
3485
3486                 /*
3487                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3488                  * upon those conditions:
3489                  * - C1: abut_ex is initialized,
3490                  * - C2: abut_ex is logically abutting ex,
3491                  * - C3: abut_ex is physically abutting ex,
3492                  * - C4: abut_ex can receive the additional blocks without
3493                  *   overflowing the (initialized) length limit.
3494                  */
3495                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3496                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3497                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3498                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3499                         err = ext4_ext_get_access(handle, inode, path + depth);
3500                         if (err)
3501                                 goto out;
3502
3503                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3504                                 map, ex, abut_ex);
3505
3506                         /* Shift the start of ex by 'map_len' blocks */
3507                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3508                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3509                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3510                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3511
3512                         /* Extend abut_ex by 'map_len' blocks */
3513                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3514
3515                         /* Result: number of initialized blocks past m_lblk */
3516                         allocated = map_len;
3517                 }
3518         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3519                    (map_len < ee_len) &&        /*L1*/
3520                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3521                 /* See if we can merge right */
3522                 ext4_lblk_t next_lblk;
3523                 ext4_fsblk_t next_pblk, ee_pblk;
3524                 unsigned int next_len;
3525
3526                 abut_ex = ex + 1;
3527                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3528                 next_len = ext4_ext_get_actual_len(abut_ex);
3529                 next_pblk = ext4_ext_pblock(abut_ex);
3530                 ee_pblk = ext4_ext_pblock(ex);
3531
3532                 /*
3533                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3534                  * upon those conditions:
3535                  * - C1: abut_ex is initialized,
3536                  * - C2: abut_ex is logically abutting ex,
3537                  * - C3: abut_ex is physically abutting ex,
3538                  * - C4: abut_ex can receive the additional blocks without
3539                  *   overflowing the (initialized) length limit.
3540                  */
3541                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3542                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3543                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3544                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3545                         err = ext4_ext_get_access(handle, inode, path + depth);
3546                         if (err)
3547                                 goto out;
3548
3549                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3550                                 map, ex, abut_ex);
3551
3552                         /* Shift the start of abut_ex by 'map_len' blocks */
3553                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3554                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3555                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3556                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3557
3558                         /* Extend abut_ex by 'map_len' blocks */
3559                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3560
3561                         /* Result: number of initialized blocks past m_lblk */
3562                         allocated = map_len;
3563                 }
3564         }
3565         if (allocated) {
3566                 /* Mark the block containing both extents as dirty */
3567                 err = ext4_ext_dirty(handle, inode, path + depth);
3568
3569                 /* Update path to point to the right extent */
3570                 path[depth].p_ext = abut_ex;
3571                 goto out;
3572         } else
3573                 allocated = ee_len - (map->m_lblk - ee_block);
3574
3575         WARN_ON(map->m_lblk < ee_block);
3576         /*
3577          * It is safe to convert extent to initialized via explicit
3578          * zeroout only if extent is fully inside i_size or new_size.
3579          */
3580         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3581
3582         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3583                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3584                         (inode->i_sb->s_blocksize_bits - 10);
3585
3586         /*
3587          * five cases:
3588          * 1. split the extent into three extents.
3589          * 2. split the extent into two extents, zeroout the head of the first
3590          *    extent.
3591          * 3. split the extent into two extents, zeroout the tail of the second
3592          *    extent.
3593          * 4. split the extent into two extents with out zeroout.
3594          * 5. no splitting needed, just possibly zeroout the head and / or the
3595          *    tail of the extent.
3596          */
3597         split_map.m_lblk = map->m_lblk;
3598         split_map.m_len = map->m_len;
3599
3600         if (max_zeroout && (allocated > split_map.m_len)) {
3601                 if (allocated <= max_zeroout) {
3602                         /* case 3 or 5 */
3603                         zero_ex1.ee_block =
3604                                  cpu_to_le32(split_map.m_lblk +
3605                                              split_map.m_len);
3606                         zero_ex1.ee_len =
3607                                 cpu_to_le16(allocated - split_map.m_len);
3608                         ext4_ext_store_pblock(&zero_ex1,
3609                                 ext4_ext_pblock(ex) + split_map.m_lblk +
3610                                 split_map.m_len - ee_block);
3611                         err = ext4_ext_zeroout(inode, &zero_ex1);
3612                         if (err)
3613                                 goto fallback;
3614                         split_map.m_len = allocated;
3615                 }
3616                 if (split_map.m_lblk - ee_block + split_map.m_len <
3617                                                                 max_zeroout) {
3618                         /* case 2 or 5 */
3619                         if (split_map.m_lblk != ee_block) {
3620                                 zero_ex2.ee_block = ex->ee_block;
3621                                 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3622                                                         ee_block);
3623                                 ext4_ext_store_pblock(&zero_ex2,
3624                                                       ext4_ext_pblock(ex));
3625                                 err = ext4_ext_zeroout(inode, &zero_ex2);
3626                                 if (err)
3627                                         goto fallback;
3628                         }
3629
3630                         split_map.m_len += split_map.m_lblk - ee_block;
3631                         split_map.m_lblk = ee_block;
3632                         allocated = map->m_len;
3633                 }
3634         }
3635
3636 fallback:
3637         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3638                                 flags);
3639         if (err > 0)
3640                 err = 0;
3641 out:
3642         /* If we have gotten a failure, don't zero out status tree */
3643         if (!err) {
3644                 err = ext4_zeroout_es(inode, &zero_ex1);
3645                 if (!err)
3646                         err = ext4_zeroout_es(inode, &zero_ex2);
3647         }
3648         return err ? err : allocated;
3649 }
3650
3651 /*
3652  * This function is called by ext4_ext_map_blocks() from
3653  * ext4_get_blocks_dio_write() when DIO to write
3654  * to an unwritten extent.
3655  *
3656  * Writing to an unwritten extent may result in splitting the unwritten
3657  * extent into multiple initialized/unwritten extents (up to three)
3658  * There are three possibilities:
3659  *   a> There is no split required: Entire extent should be unwritten
3660  *   b> Splits in two extents: Write is happening at either end of the extent
3661  *   c> Splits in three extents: Somone is writing in middle of the extent
3662  *
3663  * This works the same way in the case of initialized -> unwritten conversion.
3664  *
3665  * One of more index blocks maybe needed if the extent tree grow after
3666  * the unwritten extent split. To prevent ENOSPC occur at the IO
3667  * complete, we need to split the unwritten extent before DIO submit
3668  * the IO. The unwritten extent called at this time will be split
3669  * into three unwritten extent(at most). After IO complete, the part
3670  * being filled will be convert to initialized by the end_io callback function
3671  * via ext4_convert_unwritten_extents().
3672  *
3673  * Returns the size of unwritten extent to be written on success.
3674  */
3675 static int ext4_split_convert_extents(handle_t *handle,
3676                                         struct inode *inode,
3677                                         struct ext4_map_blocks *map,
3678                                         struct ext4_ext_path **ppath,
3679                                         int flags)
3680 {
3681         struct ext4_ext_path *path = *ppath;
3682         ext4_lblk_t eof_block;
3683         ext4_lblk_t ee_block;
3684         struct ext4_extent *ex;
3685         unsigned int ee_len;
3686         int split_flag = 0, depth;
3687
3688         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3689                   (unsigned long long)map->m_lblk, map->m_len);
3690
3691         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3692                         >> inode->i_sb->s_blocksize_bits;
3693         if (eof_block < map->m_lblk + map->m_len)
3694                 eof_block = map->m_lblk + map->m_len;
3695         /*
3696          * It is safe to convert extent to initialized via explicit
3697          * zeroout only if extent is fully inside i_size or new_size.
3698          */
3699         depth = ext_depth(inode);
3700         ex = path[depth].p_ext;
3701         ee_block = le32_to_cpu(ex->ee_block);
3702         ee_len = ext4_ext_get_actual_len(ex);
3703
3704         /* Convert to unwritten */
3705         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3706                 split_flag |= EXT4_EXT_DATA_VALID1;
3707         /* Convert to initialized */
3708         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3709                 split_flag |= ee_block + ee_len <= eof_block ?
3710                               EXT4_EXT_MAY_ZEROOUT : 0;
3711                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3712         }
3713         flags |= EXT4_GET_BLOCKS_PRE_IO;
3714         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3715 }
3716
3717 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3718                                                 struct inode *inode,
3719                                                 struct ext4_map_blocks *map,
3720                                                 struct ext4_ext_path **ppath)
3721 {
3722         struct ext4_ext_path *path = *ppath;
3723         struct ext4_extent *ex;
3724         ext4_lblk_t ee_block;
3725         unsigned int ee_len;
3726         int depth;
3727         int err = 0;
3728
3729         depth = ext_depth(inode);
3730         ex = path[depth].p_ext;
3731         ee_block = le32_to_cpu(ex->ee_block);
3732         ee_len = ext4_ext_get_actual_len(ex);
3733
3734         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3735                   (unsigned long long)ee_block, ee_len);
3736
3737         /* If extent is larger than requested it is a clear sign that we still
3738          * have some extent state machine issues left. So extent_split is still
3739          * required.
3740          * TODO: Once all related issues will be fixed this situation should be
3741          * illegal.
3742          */
3743         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3744 #ifdef CONFIG_EXT4_DEBUG
3745                 ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3746                              " len %u; IO logical block %llu, len %u",
3747                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3748                              (unsigned long long)map->m_lblk, map->m_len);
3749 #endif
3750                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3751                                                  EXT4_GET_BLOCKS_CONVERT);
3752                 if (err < 0)
3753                         return err;
3754                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3755                 if (IS_ERR(path))
3756                         return PTR_ERR(path);
3757                 depth = ext_depth(inode);
3758                 ex = path[depth].p_ext;
3759         }
3760
3761         err = ext4_ext_get_access(handle, inode, path + depth);
3762         if (err)
3763                 goto out;
3764         /* first mark the extent as initialized */
3765         ext4_ext_mark_initialized(ex);
3766
3767         /* note: ext4_ext_correct_indexes() isn't needed here because
3768          * borders are not changed
3769          */
3770         ext4_ext_try_to_merge(handle, inode, path, ex);
3771
3772         /* Mark modified extent as dirty */
3773         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3774 out:
3775         ext4_ext_show_leaf(inode, path);
3776         return err;
3777 }
3778
3779 static int
3780 convert_initialized_extent(handle_t *handle, struct inode *inode,
3781                            struct ext4_map_blocks *map,
3782                            struct ext4_ext_path **ppath,
3783                            unsigned int *allocated)
3784 {
3785         struct ext4_ext_path *path = *ppath;
3786         struct ext4_extent *ex;
3787         ext4_lblk_t ee_block;
3788         unsigned int ee_len;
3789         int depth;
3790         int err = 0;
3791
3792         /*
3793          * Make sure that the extent is no bigger than we support with
3794          * unwritten extent
3795          */
3796         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3797                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3798
3799         depth = ext_depth(inode);
3800         ex = path[depth].p_ext;
3801         ee_block = le32_to_cpu(ex->ee_block);
3802         ee_len = ext4_ext_get_actual_len(ex);
3803
3804         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3805                   (unsigned long long)ee_block, ee_len);
3806
3807         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3808                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3809                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3810                 if (err < 0)
3811                         return err;
3812                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3813                 if (IS_ERR(path))
3814                         return PTR_ERR(path);
3815                 depth = ext_depth(inode);
3816                 ex = path[depth].p_ext;
3817                 if (!ex) {
3818                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3819                                          (unsigned long) map->m_lblk);
3820                         return -EFSCORRUPTED;
3821                 }
3822         }
3823
3824         err = ext4_ext_get_access(handle, inode, path + depth);
3825         if (err)
3826                 return err;
3827         /* first mark the extent as unwritten */
3828         ext4_ext_mark_unwritten(ex);
3829
3830         /* note: ext4_ext_correct_indexes() isn't needed here because
3831          * borders are not changed
3832          */
3833         ext4_ext_try_to_merge(handle, inode, path, ex);
3834
3835         /* Mark modified extent as dirty */
3836         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3837         if (err)
3838                 return err;
3839         ext4_ext_show_leaf(inode, path);
3840
3841         ext4_update_inode_fsync_trans(handle, inode, 1);
3842
3843         map->m_flags |= EXT4_MAP_UNWRITTEN;
3844         if (*allocated > map->m_len)
3845                 *allocated = map->m_len;
3846         map->m_len = *allocated;
3847         return 0;
3848 }
3849
3850 static int
3851 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3852                         struct ext4_map_blocks *map,
3853                         struct ext4_ext_path **ppath, int flags,
3854                         unsigned int allocated, ext4_fsblk_t newblock)
3855 {
3856         struct ext4_ext_path __maybe_unused *path = *ppath;
3857         int ret = 0;
3858         int err = 0;
3859
3860         ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
3861                   (unsigned long long)map->m_lblk, map->m_len, flags,
3862                   allocated);
3863         ext4_ext_show_leaf(inode, path);
3864
3865         /*
3866          * When writing into unwritten space, we should not fail to
3867          * allocate metadata blocks for the new extent block if needed.
3868          */
3869         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3870
3871         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
3872                                                     allocated, newblock);
3873
3874         /* get_block() before submitting IO, split the extent */
3875         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
3876                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
3877                                          flags | EXT4_GET_BLOCKS_CONVERT);
3878                 if (ret < 0) {
3879                         err = ret;
3880                         goto out2;
3881                 }
3882                 /*
3883                  * shouldn't get a 0 return when splitting an extent unless
3884                  * m_len is 0 (bug) or extent has been corrupted
3885                  */
3886                 if (unlikely(ret == 0)) {
3887                         EXT4_ERROR_INODE(inode,
3888                                          "unexpected ret == 0, m_len = %u",
3889                                          map->m_len);
3890                         err = -EFSCORRUPTED;
3891                         goto out2;
3892                 }
3893                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3894                 goto out;
3895         }
3896         /* IO end_io complete, convert the filled extent to written */
3897         if (flags & EXT4_GET_BLOCKS_CONVERT) {
3898                 err = ext4_convert_unwritten_extents_endio(handle, inode, map,
3899                                                            ppath);
3900                 if (err < 0)
3901                         goto out2;
3902                 ext4_update_inode_fsync_trans(handle, inode, 1);
3903                 goto map_out;
3904         }
3905         /* buffered IO cases */
3906         /*
3907          * repeat fallocate creation request
3908          * we already have an unwritten extent
3909          */
3910         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
3911                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3912                 goto map_out;
3913         }
3914
3915         /* buffered READ or buffered write_begin() lookup */
3916         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3917                 /*
3918                  * We have blocks reserved already.  We
3919                  * return allocated blocks so that delalloc
3920                  * won't do block reservation for us.  But
3921                  * the buffer head will be unmapped so that
3922                  * a read from the block returns 0s.
3923                  */
3924                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3925                 goto out1;
3926         }
3927
3928         /*
3929          * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
3930          * For buffered writes, at writepage time, etc.  Convert a
3931          * discovered unwritten extent to written.
3932          */
3933         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
3934         if (ret < 0) {
3935                 err = ret;
3936                 goto out2;
3937         }
3938         ext4_update_inode_fsync_trans(handle, inode, 1);
3939         /*
3940          * shouldn't get a 0 return when converting an unwritten extent
3941          * unless m_len is 0 (bug) or extent has been corrupted
3942          */
3943         if (unlikely(ret == 0)) {
3944                 EXT4_ERROR_INODE(inode, "unexpected ret == 0, m_len = %u",
3945                                  map->m_len);
3946                 err = -EFSCORRUPTED;
3947                 goto out2;
3948         }
3949
3950 out:
3951         allocated = ret;
3952         map->m_flags |= EXT4_MAP_NEW;
3953 map_out:
3954         map->m_flags |= EXT4_MAP_MAPPED;
3955 out1:
3956         map->m_pblk = newblock;
3957         if (allocated > map->m_len)
3958                 allocated = map->m_len;
3959         map->m_len = allocated;
3960         ext4_ext_show_leaf(inode, path);
3961 out2:
3962         return err ? err : allocated;
3963 }
3964
3965 /*
3966  * get_implied_cluster_alloc - check to see if the requested
3967  * allocation (in the map structure) overlaps with a cluster already
3968  * allocated in an extent.
3969  *      @sb     The filesystem superblock structure
3970  *      @map    The requested lblk->pblk mapping
3971  *      @ex     The extent structure which might contain an implied
3972  *                      cluster allocation
3973  *
3974  * This function is called by ext4_ext_map_blocks() after we failed to
3975  * find blocks that were already in the inode's extent tree.  Hence,
3976  * we know that the beginning of the requested region cannot overlap
3977  * the extent from the inode's extent tree.  There are three cases we
3978  * want to catch.  The first is this case:
3979  *
3980  *               |--- cluster # N--|
3981  *    |--- extent ---|  |---- requested region ---|
3982  *                      |==========|
3983  *
3984  * The second case that we need to test for is this one:
3985  *
3986  *   |--------- cluster # N ----------------|
3987  *         |--- requested region --|   |------- extent ----|
3988  *         |=======================|
3989  *
3990  * The third case is when the requested region lies between two extents
3991  * within the same cluster:
3992  *          |------------- cluster # N-------------|
3993  * |----- ex -----|                  |---- ex_right ----|
3994  *                  |------ requested region ------|
3995  *                  |================|
3996  *
3997  * In each of the above cases, we need to set the map->m_pblk and
3998  * map->m_len so it corresponds to the return the extent labelled as
3999  * "|====|" from cluster #N, since it is already in use for data in
4000  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4001  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4002  * as a new "allocated" block region.  Otherwise, we will return 0 and
4003  * ext4_ext_map_blocks() will then allocate one or more new clusters
4004  * by calling ext4_mb_new_blocks().
4005  */
4006 static int get_implied_cluster_alloc(struct super_block *sb,
4007                                      struct ext4_map_blocks *map,
4008                                      struct ext4_extent *ex,
4009                                      struct ext4_ext_path *path)
4010 {
4011         struct ext4_sb_info *sbi = EXT4_SB(sb);
4012         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4013         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4014         ext4_lblk_t rr_cluster_start;
4015         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4016         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4017         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4018
4019         /* The extent passed in that we are trying to match */
4020         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4021         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4022
4023         /* The requested region passed into ext4_map_blocks() */
4024         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4025
4026         if ((rr_cluster_start == ex_cluster_end) ||
4027             (rr_cluster_start == ex_cluster_start)) {
4028                 if (rr_cluster_start == ex_cluster_end)
4029                         ee_start += ee_len - 1;
4030                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4031                 map->m_len = min(map->m_len,
4032                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4033                 /*
4034                  * Check for and handle this case:
4035                  *
4036                  *   |--------- cluster # N-------------|
4037                  *                     |------- extent ----|
4038                  *         |--- requested region ---|
4039                  *         |===========|
4040                  */
4041
4042                 if (map->m_lblk < ee_block)
4043                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4044
4045                 /*
4046                  * Check for the case where there is already another allocated
4047                  * block to the right of 'ex' but before the end of the cluster.
4048                  *
4049                  *          |------------- cluster # N-------------|
4050                  * |----- ex -----|                  |---- ex_right ----|
4051                  *                  |------ requested region ------|
4052                  *                  |================|
4053                  */
4054                 if (map->m_lblk > ee_block) {
4055                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4056                         map->m_len = min(map->m_len, next - map->m_lblk);
4057                 }
4058
4059                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4060                 return 1;
4061         }
4062
4063         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4064         return 0;
4065 }
4066
4067
4068 /*
4069  * Block allocation/map/preallocation routine for extents based files
4070  *
4071  *
4072  * Need to be called with
4073  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4074  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4075  *
4076  * return > 0, number of blocks already mapped/allocated
4077  *          if create == 0 and these are pre-allocated blocks
4078  *              buffer head is unmapped
4079  *          otherwise blocks are mapped
4080  *
4081  * return = 0, if plain look up failed (blocks have not been allocated)
4082  *          buffer head is unmapped
4083  *
4084  * return < 0, error case.
4085  */
4086 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4087                         struct ext4_map_blocks *map, int flags)
4088 {
4089         struct ext4_ext_path *path = NULL;
4090         struct ext4_extent newex, *ex, ex2;
4091         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4092         ext4_fsblk_t newblock = 0, pblk;
4093         int err = 0, depth, ret;
4094         unsigned int allocated = 0, offset = 0;
4095         unsigned int allocated_clusters = 0;
4096         struct ext4_allocation_request ar;
4097         ext4_lblk_t cluster_offset;
4098
4099         ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
4100         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4101
4102         /* find extent for this block */
4103         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4104         if (IS_ERR(path)) {
4105                 err = PTR_ERR(path);
4106                 path = NULL;
4107                 goto out;
4108         }
4109
4110         depth = ext_depth(inode);
4111
4112         /*
4113          * consistent leaf must not be empty;
4114          * this situation is possible, though, _during_ tree modification;
4115          * this is why assert can't be put in ext4_find_extent()
4116          */
4117         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4118                 EXT4_ERROR_INODE(inode, "bad extent address "
4119                                  "lblock: %lu, depth: %d pblock %lld",
4120                                  (unsigned long) map->m_lblk, depth,
4121                                  path[depth].p_block);
4122                 err = -EFSCORRUPTED;
4123                 goto out;
4124         }
4125
4126         ex = path[depth].p_ext;
4127         if (ex) {
4128                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4129                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4130                 unsigned short ee_len;
4131
4132
4133                 /*
4134                  * unwritten extents are treated as holes, except that
4135                  * we split out initialized portions during a write.
4136                  */
4137                 ee_len = ext4_ext_get_actual_len(ex);
4138
4139                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4140
4141                 /* if found extent covers block, simply return it */
4142                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4143                         newblock = map->m_lblk - ee_block + ee_start;
4144                         /* number of remaining blocks in the extent */
4145                         allocated = ee_len - (map->m_lblk - ee_block);
4146                         ext_debug(inode, "%u fit into %u:%d -> %llu\n",
4147                                   map->m_lblk, ee_block, ee_len, newblock);
4148
4149                         /*
4150                          * If the extent is initialized check whether the
4151                          * caller wants to convert it to unwritten.
4152                          */
4153                         if ((!ext4_ext_is_unwritten(ex)) &&
4154                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4155                                 err = convert_initialized_extent(handle,
4156                                         inode, map, &path, &allocated);
4157                                 goto out;
4158                         } else if (!ext4_ext_is_unwritten(ex)) {
4159                                 map->m_flags |= EXT4_MAP_MAPPED;
4160                                 map->m_pblk = newblock;
4161                                 if (allocated > map->m_len)
4162                                         allocated = map->m_len;
4163                                 map->m_len = allocated;
4164                                 ext4_ext_show_leaf(inode, path);
4165                                 goto out;
4166                         }
4167
4168                         ret = ext4_ext_handle_unwritten_extents(
4169                                 handle, inode, map, &path, flags,
4170                                 allocated, newblock);
4171                         if (ret < 0)
4172                                 err = ret;
4173                         else
4174                                 allocated = ret;
4175                         goto out;
4176                 }
4177         }
4178
4179         /*
4180          * requested block isn't allocated yet;
4181          * we couldn't try to create block if create flag is zero
4182          */
4183         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4184                 ext4_lblk_t hole_start, hole_len;
4185
4186                 hole_start = map->m_lblk;
4187                 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4188                 /*
4189                  * put just found gap into cache to speed up
4190                  * subsequent requests
4191                  */
4192                 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4193
4194                 /* Update hole_len to reflect hole size after map->m_lblk */
4195                 if (hole_start != map->m_lblk)
4196                         hole_len -= map->m_lblk - hole_start;
4197                 map->m_pblk = 0;
4198                 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4199
4200                 goto out;
4201         }
4202
4203         /*
4204          * Okay, we need to do block allocation.
4205          */
4206         newex.ee_block = cpu_to_le32(map->m_lblk);
4207         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4208
4209         /*
4210          * If we are doing bigalloc, check to see if the extent returned
4211          * by ext4_find_extent() implies a cluster we can use.
4212          */
4213         if (cluster_offset && ex &&
4214             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4215                 ar.len = allocated = map->m_len;
4216                 newblock = map->m_pblk;
4217                 goto got_allocated_blocks;
4218         }
4219
4220         /* find neighbour allocated blocks */
4221         ar.lleft = map->m_lblk;
4222         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4223         if (err)
4224                 goto out;
4225         ar.lright = map->m_lblk;
4226         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4227         if (err < 0)
4228                 goto out;
4229
4230         /* Check if the extent after searching to the right implies a
4231          * cluster we can use. */
4232         if ((sbi->s_cluster_ratio > 1) && err &&
4233             get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
4234                 ar.len = allocated = map->m_len;
4235                 newblock = map->m_pblk;
4236                 goto got_allocated_blocks;
4237         }
4238
4239         /*
4240          * See if request is beyond maximum number of blocks we can have in
4241          * a single extent. For an initialized extent this limit is
4242          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4243          * EXT_UNWRITTEN_MAX_LEN.
4244          */
4245         if (map->m_len > EXT_INIT_MAX_LEN &&
4246             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4247                 map->m_len = EXT_INIT_MAX_LEN;
4248         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4249                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4250                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4251
4252         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4253         newex.ee_len = cpu_to_le16(map->m_len);
4254         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4255         if (err)
4256                 allocated = ext4_ext_get_actual_len(&newex);
4257         else
4258                 allocated = map->m_len;
4259
4260         /* allocate new block */
4261         ar.inode = inode;
4262         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4263         ar.logical = map->m_lblk;
4264         /*
4265          * We calculate the offset from the beginning of the cluster
4266          * for the logical block number, since when we allocate a
4267          * physical cluster, the physical block should start at the
4268          * same offset from the beginning of the cluster.  This is
4269          * needed so that future calls to get_implied_cluster_alloc()
4270          * work correctly.
4271          */
4272         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4273         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4274         ar.goal -= offset;
4275         ar.logical -= offset;
4276         if (S_ISREG(inode->i_mode))
4277                 ar.flags = EXT4_MB_HINT_DATA;
4278         else
4279                 /* disable in-core preallocation for non-regular files */
4280                 ar.flags = 0;
4281         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4282                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4283         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4284                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4285         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4286                 ar.flags |= EXT4_MB_USE_RESERVED;
4287         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4288         if (!newblock)
4289                 goto out;
4290         allocated_clusters = ar.len;
4291         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4292         ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
4293                   ar.goal, newblock, ar.len, allocated);
4294         if (ar.len > allocated)
4295                 ar.len = allocated;
4296
4297 got_allocated_blocks:
4298         /* try to insert new extent into found leaf and return */
4299         pblk = newblock + offset;
4300         ext4_ext_store_pblock(&newex, pblk);
4301         newex.ee_len = cpu_to_le16(ar.len);
4302         /* Mark unwritten */
4303         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4304                 ext4_ext_mark_unwritten(&newex);
4305                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4306         }
4307
4308         err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags);
4309         if (err) {
4310                 if (allocated_clusters) {
4311                         int fb_flags = 0;
4312
4313                         /*
4314                          * free data blocks we just allocated.
4315                          * not a good idea to call discard here directly,
4316                          * but otherwise we'd need to call it every free().
4317                          */
4318                         ext4_discard_preallocations(inode, 0);
4319                         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4320                                 fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
4321                         ext4_free_blocks(handle, inode, NULL, newblock,
4322                                          EXT4_C2B(sbi, allocated_clusters),
4323                                          fb_flags);
4324                 }
4325                 goto out;
4326         }
4327
4328         /*
4329          * Reduce the reserved cluster count to reflect successful deferred
4330          * allocation of delayed allocated clusters or direct allocation of
4331          * clusters discovered to be delayed allocated.  Once allocated, a
4332          * cluster is not included in the reserved count.
4333          */
4334         if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
4335                 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4336                         /*
4337                          * When allocating delayed allocated clusters, simply
4338                          * reduce the reserved cluster count and claim quota
4339                          */
4340                         ext4_da_update_reserve_space(inode, allocated_clusters,
4341                                                         1);
4342                 } else {
4343                         ext4_lblk_t lblk, len;
4344                         unsigned int n;
4345
4346                         /*
4347                          * When allocating non-delayed allocated clusters
4348                          * (from fallocate, filemap, DIO, or clusters
4349                          * allocated when delalloc has been disabled by
4350                          * ext4_nonda_switch), reduce the reserved cluster
4351                          * count by the number of allocated clusters that
4352                          * have previously been delayed allocated.  Quota
4353                          * has been claimed by ext4_mb_new_blocks() above,
4354                          * so release the quota reservations made for any
4355                          * previously delayed allocated clusters.
4356                          */
4357                         lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4358                         len = allocated_clusters << sbi->s_cluster_bits;
4359                         n = ext4_es_delayed_clu(inode, lblk, len);
4360                         if (n > 0)
4361                                 ext4_da_update_reserve_space(inode, (int) n, 0);
4362                 }
4363         }
4364
4365         /*
4366          * Cache the extent and update transaction to commit on fdatasync only
4367          * when it is _not_ an unwritten extent.
4368          */
4369         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4370                 ext4_update_inode_fsync_trans(handle, inode, 1);
4371         else
4372                 ext4_update_inode_fsync_trans(handle, inode, 0);
4373
4374         map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
4375         map->m_pblk = pblk;
4376         map->m_len = ar.len;
4377         allocated = map->m_len;
4378         ext4_ext_show_leaf(inode, path);
4379 out:
4380         ext4_free_ext_path(path);
4381
4382         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4383                                        err ? err : allocated);
4384         return err ? err : allocated;
4385 }
4386
4387 int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4388 {
4389         struct super_block *sb = inode->i_sb;
4390         ext4_lblk_t last_block;
4391         int err = 0;
4392
4393         /*
4394          * TODO: optimization is possible here.
4395          * Probably we need not scan at all,
4396          * because page truncation is enough.
4397          */
4398
4399         /* we have to know where to truncate from in crash case */
4400         EXT4_I(inode)->i_disksize = inode->i_size;
4401         err = ext4_mark_inode_dirty(handle, inode);
4402         if (err)
4403                 return err;
4404
4405         last_block = (inode->i_size + sb->s_blocksize - 1)
4406                         >> EXT4_BLOCK_SIZE_BITS(sb);
4407 retry:
4408         err = ext4_es_remove_extent(inode, last_block,
4409                                     EXT_MAX_BLOCKS - last_block);
4410         if (err == -ENOMEM) {
4411                 memalloc_retry_wait(GFP_ATOMIC);
4412                 goto retry;
4413         }
4414         if (err)
4415                 return err;
4416 retry_remove_space:
4417         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4418         if (err == -ENOMEM) {
4419                 memalloc_retry_wait(GFP_ATOMIC);
4420                 goto retry_remove_space;
4421         }
4422         return err;
4423 }
4424
4425 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4426                                   ext4_lblk_t len, loff_t new_size,
4427                                   int flags)
4428 {
4429         struct inode *inode = file_inode(file);
4430         handle_t *handle;
4431         int ret = 0, ret2 = 0, ret3 = 0;
4432         int retries = 0;
4433         int depth = 0;
4434         struct ext4_map_blocks map;
4435         unsigned int credits;
4436         loff_t epos;
4437
4438         BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4439         map.m_lblk = offset;
4440         map.m_len = len;
4441         /*
4442          * Don't normalize the request if it can fit in one extent so
4443          * that it doesn't get unnecessarily split into multiple
4444          * extents.
4445          */
4446         if (len <= EXT_UNWRITTEN_MAX_LEN)
4447                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4448
4449         /*
4450          * credits to insert 1 extent into extent tree
4451          */
4452         credits = ext4_chunk_trans_blocks(inode, len);
4453         depth = ext_depth(inode);
4454
4455 retry:
4456         while (len) {
4457                 /*
4458                  * Recalculate credits when extent tree depth changes.
4459                  */
4460                 if (depth != ext_depth(inode)) {
4461                         credits = ext4_chunk_trans_blocks(inode, len);
4462                         depth = ext_depth(inode);
4463                 }
4464
4465                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4466                                             credits);
4467                 if (IS_ERR(handle)) {
4468                         ret = PTR_ERR(handle);
4469                         break;
4470                 }
4471                 ret = ext4_map_blocks(handle, inode, &map, flags);
4472                 if (ret <= 0) {
4473                         ext4_debug("inode #%lu: block %u: len %u: "
4474                                    "ext4_ext_map_blocks returned %d",
4475                                    inode->i_ino, map.m_lblk,
4476                                    map.m_len, ret);
4477                         ext4_mark_inode_dirty(handle, inode);
4478                         ext4_journal_stop(handle);
4479                         break;
4480                 }
4481                 /*
4482                  * allow a full retry cycle for any remaining allocations
4483                  */
4484                 retries = 0;
4485                 map.m_lblk += ret;
4486                 map.m_len = len = len - ret;
4487                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4488                 inode->i_ctime = current_time(inode);
4489                 if (new_size) {
4490                         if (epos > new_size)
4491                                 epos = new_size;
4492                         if (ext4_update_inode_size(inode, epos) & 0x1)
4493                                 inode->i_mtime = inode->i_ctime;
4494                 }
4495                 ret2 = ext4_mark_inode_dirty(handle, inode);
4496                 ext4_update_inode_fsync_trans(handle, inode, 1);
4497                 ret3 = ext4_journal_stop(handle);
4498                 ret2 = ret3 ? ret3 : ret2;
4499                 if (unlikely(ret2))
4500                         break;
4501         }
4502         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
4503                 goto retry;
4504
4505         return ret > 0 ? ret2 : ret;
4506 }
4507
4508 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);
4509
4510 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
4511
4512 static long ext4_zero_range(struct file *file, loff_t offset,
4513                             loff_t len, int mode)
4514 {
4515         struct inode *inode = file_inode(file);
4516         struct address_space *mapping = file->f_mapping;
4517         handle_t *handle = NULL;
4518         unsigned int max_blocks;
4519         loff_t new_size = 0;
4520         int ret = 0;
4521         int flags;
4522         int credits;
4523         int partial_begin, partial_end;
4524         loff_t start, end;
4525         ext4_lblk_t lblk;
4526         unsigned int blkbits = inode->i_blkbits;
4527
4528         trace_ext4_zero_range(inode, offset, len, mode);
4529
4530         /* Call ext4_force_commit to flush all data in case of data=journal. */
4531         if (ext4_should_journal_data(inode)) {
4532                 ret = ext4_force_commit(inode->i_sb);
4533                 if (ret)
4534                         return ret;
4535         }
4536
4537         /*
4538          * Round up offset. This is not fallocate, we need to zero out
4539          * blocks, so convert interior block aligned part of the range to
4540          * unwritten and possibly manually zero out unaligned parts of the
4541          * range.
4542          */
4543         start = round_up(offset, 1 << blkbits);
4544         end = round_down((offset + len), 1 << blkbits);
4545
4546         if (start < offset || end > offset + len)
4547                 return -EINVAL;
4548         partial_begin = offset & ((1 << blkbits) - 1);
4549         partial_end = (offset + len) & ((1 << blkbits) - 1);
4550
4551         lblk = start >> blkbits;
4552         max_blocks = (end >> blkbits);
4553         if (max_blocks < lblk)
4554                 max_blocks = 0;
4555         else
4556                 max_blocks -= lblk;
4557
4558         inode_lock(inode);
4559
4560         /*
4561          * Indirect files do not support unwritten extents
4562          */
4563         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4564                 ret = -EOPNOTSUPP;
4565                 goto out_mutex;
4566         }
4567
4568         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4569             (offset + len > inode->i_size ||
4570              offset + len > EXT4_I(inode)->i_disksize)) {
4571                 new_size = offset + len;
4572                 ret = inode_newsize_ok(inode, new_size);
4573                 if (ret)
4574                         goto out_mutex;
4575         }
4576
4577         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4578
4579         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4580         inode_dio_wait(inode);
4581
4582         ret = file_modified(file);
4583         if (ret)
4584                 goto out_mutex;
4585
4586         /* Preallocate the range including the unaligned edges */
4587         if (partial_begin || partial_end) {
4588                 ret = ext4_alloc_file_blocks(file,
4589                                 round_down(offset, 1 << blkbits) >> blkbits,
4590                                 (round_up((offset + len), 1 << blkbits) -
4591                                  round_down(offset, 1 << blkbits)) >> blkbits,
4592                                 new_size, flags);
4593                 if (ret)
4594                         goto out_mutex;
4595
4596         }
4597
4598         /* Zero range excluding the unaligned edges */
4599         if (max_blocks > 0) {
4600                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4601                           EXT4_EX_NOCACHE);
4602
4603                 /*
4604                  * Prevent page faults from reinstantiating pages we have
4605                  * released from page cache.
4606                  */
4607                 filemap_invalidate_lock(mapping);
4608
4609                 ret = ext4_break_layouts(inode);
4610                 if (ret) {
4611                         filemap_invalidate_unlock(mapping);
4612                         goto out_mutex;
4613                 }
4614
4615                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4616                 if (ret) {
4617                         filemap_invalidate_unlock(mapping);
4618                         goto out_mutex;
4619                 }
4620                 /* Now release the pages and zero block aligned part of pages */
4621                 truncate_pagecache_range(inode, start, end - 1);
4622                 inode->i_mtime = inode->i_ctime = current_time(inode);
4623
4624                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4625                                              flags);
4626                 filemap_invalidate_unlock(mapping);
4627                 if (ret)
4628                         goto out_mutex;
4629         }
4630         if (!partial_begin && !partial_end)
4631                 goto out_mutex;
4632
4633         /*
4634          * In worst case we have to writeout two nonadjacent unwritten
4635          * blocks and update the inode
4636          */
4637         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4638         if (ext4_should_journal_data(inode))
4639                 credits += 2;
4640         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4641         if (IS_ERR(handle)) {
4642                 ret = PTR_ERR(handle);
4643                 ext4_std_error(inode->i_sb, ret);
4644                 goto out_mutex;
4645         }
4646
4647         inode->i_mtime = inode->i_ctime = current_time(inode);
4648         if (new_size)
4649                 ext4_update_inode_size(inode, new_size);
4650         ret = ext4_mark_inode_dirty(handle, inode);
4651         if (unlikely(ret))
4652                 goto out_handle;
4653         /* Zero out partial block at the edges of the range */
4654         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4655         if (ret >= 0)
4656                 ext4_update_inode_fsync_trans(handle, inode, 1);
4657
4658         if (file->f_flags & O_SYNC)
4659                 ext4_handle_sync(handle);
4660
4661 out_handle:
4662         ext4_journal_stop(handle);
4663 out_mutex:
4664         inode_unlock(inode);
4665         return ret;
4666 }
4667
4668 /*
4669  * preallocate space for a file. This implements ext4's fallocate file
4670  * operation, which gets called from sys_fallocate system call.
4671  * For block-mapped files, posix_fallocate should fall back to the method
4672  * of writing zeroes to the required new blocks (the same behavior which is
4673  * expected for file systems which do not support fallocate() system call).
4674  */
4675 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4676 {
4677         struct inode *inode = file_inode(file);
4678         loff_t new_size = 0;
4679         unsigned int max_blocks;
4680         int ret = 0;
4681         int flags;
4682         ext4_lblk_t lblk;
4683         unsigned int blkbits = inode->i_blkbits;
4684
4685         /*
4686          * Encrypted inodes can't handle collapse range or insert
4687          * range since we would need to re-encrypt blocks with a
4688          * different IV or XTS tweak (which are based on the logical
4689          * block number).
4690          */
4691         if (IS_ENCRYPTED(inode) &&
4692             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
4693                 return -EOPNOTSUPP;
4694
4695         /* Return error if mode is not supported */
4696         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4697                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4698                      FALLOC_FL_INSERT_RANGE))
4699                 return -EOPNOTSUPP;
4700
4701         inode_lock(inode);
4702         ret = ext4_convert_inline_data(inode);
4703         inode_unlock(inode);
4704         if (ret)
4705                 goto exit;
4706
4707         if (mode & FALLOC_FL_PUNCH_HOLE) {
4708                 ret = ext4_punch_hole(file, offset, len);
4709                 goto exit;
4710         }
4711
4712         if (mode & FALLOC_FL_COLLAPSE_RANGE) {
4713                 ret = ext4_collapse_range(file, offset, len);
4714                 goto exit;
4715         }
4716
4717         if (mode & FALLOC_FL_INSERT_RANGE) {
4718                 ret = ext4_insert_range(file, offset, len);
4719                 goto exit;
4720         }
4721
4722         if (mode & FALLOC_FL_ZERO_RANGE) {
4723                 ret = ext4_zero_range(file, offset, len, mode);
4724                 goto exit;
4725         }
4726         trace_ext4_fallocate_enter(inode, offset, len, mode);
4727         lblk = offset >> blkbits;
4728
4729         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4730         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4731
4732         inode_lock(inode);
4733
4734         /*
4735          * We only support preallocation for extent-based files only
4736          */
4737         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4738                 ret = -EOPNOTSUPP;
4739                 goto out;
4740         }
4741
4742         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4743             (offset + len > inode->i_size ||
4744              offset + len > EXT4_I(inode)->i_disksize)) {
4745                 new_size = offset + len;
4746                 ret = inode_newsize_ok(inode, new_size);
4747                 if (ret)
4748                         goto out;
4749         }
4750
4751         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4752         inode_dio_wait(inode);
4753
4754         ret = file_modified(file);
4755         if (ret)
4756                 goto out;
4757
4758         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4759         if (ret)
4760                 goto out;
4761
4762         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4763                 ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
4764                                         EXT4_I(inode)->i_sync_tid);
4765         }
4766 out:
4767         inode_unlock(inode);
4768         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4769 exit:
4770         return ret;
4771 }
4772
4773 /*
4774  * This function convert a range of blocks to written extents
4775  * The caller of this function will pass the start offset and the size.
4776  * all unwritten extents within this range will be converted to
4777  * written extents.
4778  *
4779  * This function is called from the direct IO end io call back
4780  * function, to convert the fallocated extents after IO is completed.
4781  * Returns 0 on success.
4782  */
4783 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4784                                    loff_t offset, ssize_t len)
4785 {
4786         unsigned int max_blocks;
4787         int ret = 0, ret2 = 0, ret3 = 0;
4788         struct ext4_map_blocks map;
4789         unsigned int blkbits = inode->i_blkbits;
4790         unsigned int credits = 0;
4791
4792         map.m_lblk = offset >> blkbits;
4793         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4794
4795         if (!handle) {
4796                 /*
4797                  * credits to insert 1 extent into extent tree
4798                  */
4799                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4800         }
4801         while (ret >= 0 && ret < max_blocks) {
4802                 map.m_lblk += ret;
4803                 map.m_len = (max_blocks -= ret);
4804                 if (credits) {
4805                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4806                                                     credits);
4807                         if (IS_ERR(handle)) {
4808                                 ret = PTR_ERR(handle);
4809                                 break;
4810                         }
4811                 }
4812                 ret = ext4_map_blocks(handle, inode, &map,
4813                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4814                 if (ret <= 0)
4815                         ext4_warning(inode->i_sb,
4816                                      "inode #%lu: block %u: len %u: "
4817                                      "ext4_ext_map_blocks returned %d",
4818                                      inode->i_ino, map.m_lblk,
4819                                      map.m_len, ret);
4820                 ret2 = ext4_mark_inode_dirty(handle, inode);
4821                 if (credits) {
4822                         ret3 = ext4_journal_stop(handle);
4823                         if (unlikely(ret3))
4824                                 ret2 = ret3;
4825                 }
4826
4827                 if (ret <= 0 || ret2)
4828                         break;
4829         }
4830         return ret > 0 ? ret2 : ret;
4831 }
4832
4833 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
4834 {
4835         int ret = 0, err = 0;
4836         struct ext4_io_end_vec *io_end_vec;
4837
4838         /*
4839          * This is somewhat ugly but the idea is clear: When transaction is
4840          * reserved, everything goes into it. Otherwise we rather start several
4841          * smaller transactions for conversion of each extent separately.
4842          */
4843         if (handle) {
4844                 handle = ext4_journal_start_reserved(handle,
4845                                                      EXT4_HT_EXT_CONVERT);
4846                 if (IS_ERR(handle))
4847                         return PTR_ERR(handle);
4848         }
4849
4850         list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4851                 ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4852                                                      io_end_vec->offset,
4853                                                      io_end_vec->size);
4854                 if (ret)
4855                         break;
4856         }
4857
4858         if (handle)
4859                 err = ext4_journal_stop(handle);
4860
4861         return ret < 0 ? ret : err;
4862 }
4863
4864 static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
4865 {
4866         __u64 physical = 0;
4867         __u64 length = 0;
4868         int blockbits = inode->i_sb->s_blocksize_bits;
4869         int error = 0;
4870         u16 iomap_type;
4871
4872         /* in-inode? */
4873         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4874                 struct ext4_iloc iloc;
4875                 int offset;     /* offset of xattr in inode */
4876
4877                 error = ext4_get_inode_loc(inode, &iloc);
4878                 if (error)
4879                         return error;
4880                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
4881                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4882                                 EXT4_I(inode)->i_extra_isize;
4883                 physical += offset;
4884                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4885                 brelse(iloc.bh);
4886                 iomap_type = IOMAP_INLINE;
4887         } else if (EXT4_I(inode)->i_file_acl) { /* external block */
4888                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4889                 length = inode->i_sb->s_blocksize;
4890                 iomap_type = IOMAP_MAPPED;
4891         } else {
4892                 /* no in-inode or external block for xattr, so return -ENOENT */
4893                 error = -ENOENT;
4894                 goto out;
4895         }
4896
4897         iomap->addr = physical;
4898         iomap->offset = 0;
4899         iomap->length = length;
4900         iomap->type = iomap_type;
4901         iomap->flags = 0;
4902 out:
4903         return error;
4904 }
4905
4906 static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
4907                                   loff_t length, unsigned flags,
4908                                   struct iomap *iomap, struct iomap *srcmap)
4909 {
4910         int error;
4911
4912         error = ext4_iomap_xattr_fiemap(inode, iomap);
4913         if (error == 0 && (offset >= iomap->length))
4914                 error = -ENOENT;
4915         return error;
4916 }
4917
4918 static const struct iomap_ops ext4_iomap_xattr_ops = {
4919         .iomap_begin            = ext4_iomap_xattr_begin,
4920 };
4921
4922 static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
4923 {
4924         u64 maxbytes;
4925
4926         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4927                 maxbytes = inode->i_sb->s_maxbytes;
4928         else
4929                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
4930
4931         if (*len == 0)
4932                 return -EINVAL;
4933         if (start > maxbytes)
4934                 return -EFBIG;
4935
4936         /*
4937          * Shrink request scope to what the fs can actually handle.
4938          */
4939         if (*len > maxbytes || (maxbytes - *len) < start)
4940                 *len = maxbytes - start;
4941         return 0;
4942 }
4943
4944 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4945                 u64 start, u64 len)
4946 {
4947         int error = 0;
4948
4949         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4950                 error = ext4_ext_precache(inode);
4951                 if (error)
4952                         return error;
4953                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4954         }
4955
4956         /*
4957          * For bitmap files the maximum size limit could be smaller than
4958          * s_maxbytes, so check len here manually instead of just relying on the
4959          * generic check.
4960          */
4961         error = ext4_fiemap_check_ranges(inode, start, &len);
4962         if (error)
4963                 return error;
4964
4965         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4966                 fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
4967                 return iomap_fiemap(inode, fieinfo, start, len,
4968                                     &ext4_iomap_xattr_ops);
4969         }
4970
4971         return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
4972 }
4973
4974 int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
4975                       __u64 start, __u64 len)
4976 {
4977         ext4_lblk_t start_blk, len_blks;
4978         __u64 last_blk;
4979         int error = 0;
4980
4981         if (ext4_has_inline_data(inode)) {
4982                 int has_inline;
4983
4984                 down_read(&EXT4_I(inode)->xattr_sem);
4985                 has_inline = ext4_has_inline_data(inode);
4986                 up_read(&EXT4_I(inode)->xattr_sem);
4987                 if (has_inline)
4988                         return 0;
4989         }
4990
4991         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4992                 error = ext4_ext_precache(inode);
4993                 if (error)
4994                         return error;
4995                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4996         }
4997
4998         error = fiemap_prep(inode, fieinfo, start, &len, 0);
4999         if (error)
5000                 return error;
5001
5002         error = ext4_fiemap_check_ranges(inode, start, &len);
5003         if (error)
5004                 return error;
5005
5006         start_blk = start >> inode->i_sb->s_blocksize_bits;
5007         last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5008         if (last_blk >= EXT_MAX_BLOCKS)
5009                 last_blk = EXT_MAX_BLOCKS-1;
5010         len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5011
5012         /*
5013          * Walk the extent tree gathering extent information
5014          * and pushing extents back to the user.
5015          */
5016         return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
5017 }
5018
5019 /*
5020  * ext4_ext_shift_path_extents:
5021  * Shift the extents of a path structure lying between path[depth].p_ext
5022  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5023  * if it is right shift or left shift operation.
5024  */
5025 static int
5026 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5027                             struct inode *inode, handle_t *handle,
5028                             enum SHIFT_DIRECTION SHIFT)
5029 {
5030         int depth, err = 0;
5031         struct ext4_extent *ex_start, *ex_last;
5032         bool update = false;
5033         int credits, restart_credits;
5034         depth = path->p_depth;
5035
5036         while (depth >= 0) {
5037                 if (depth == path->p_depth) {
5038                         ex_start = path[depth].p_ext;
5039                         if (!ex_start)
5040                                 return -EFSCORRUPTED;
5041
5042                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5043                         /* leaf + sb + inode */
5044                         credits = 3;
5045                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
5046                                 update = true;
5047                                 /* extent tree + sb + inode */
5048                                 credits = depth + 2;
5049                         }
5050
5051                         restart_credits = ext4_writepage_trans_blocks(inode);
5052                         err = ext4_datasem_ensure_credits(handle, inode, credits,
5053                                         restart_credits, 0);
5054                         if (err) {
5055                                 if (err > 0)
5056                                         err = -EAGAIN;
5057                                 goto out;
5058                         }
5059
5060                         err = ext4_ext_get_access(handle, inode, path + depth);
5061                         if (err)
5062                                 goto out;
5063
5064                         while (ex_start <= ex_last) {
5065                                 if (SHIFT == SHIFT_LEFT) {
5066                                         le32_add_cpu(&ex_start->ee_block,
5067                                                 -shift);
5068                                         /* Try to merge to the left. */
5069                                         if ((ex_start >
5070                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5071                                             &&
5072                                             ext4_ext_try_to_merge_right(inode,
5073                                             path, ex_start - 1))
5074                                                 ex_last--;
5075                                         else
5076                                                 ex_start++;
5077                                 } else {
5078                                         le32_add_cpu(&ex_last->ee_block, shift);
5079                                         ext4_ext_try_to_merge_right(inode, path,
5080                                                 ex_last);
5081                                         ex_last--;
5082                                 }
5083                         }
5084                         err = ext4_ext_dirty(handle, inode, path + depth);
5085                         if (err)
5086                                 goto out;
5087
5088                         if (--depth < 0 || !update)
5089                                 break;
5090                 }
5091
5092                 /* Update index too */
5093                 err = ext4_ext_get_access(handle, inode, path + depth);
5094                 if (err)
5095                         goto out;
5096
5097                 if (SHIFT == SHIFT_LEFT)
5098                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5099                 else
5100                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5101                 err = ext4_ext_dirty(handle, inode, path + depth);
5102                 if (err)
5103                         goto out;
5104
5105                 /* we are done if current index is not a starting index */
5106                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5107                         break;
5108
5109                 depth--;
5110         }
5111
5112 out:
5113         return err;
5114 }
5115
5116 /*
5117  * ext4_ext_shift_extents:
5118  * All the extents which lies in the range from @start to the last allocated
5119  * block for the @inode are shifted either towards left or right (depending
5120  * upon @SHIFT) by @shift blocks.
5121  * On success, 0 is returned, error otherwise.
5122  */
5123 static int
5124 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5125                        ext4_lblk_t start, ext4_lblk_t shift,
5126                        enum SHIFT_DIRECTION SHIFT)
5127 {
5128         struct ext4_ext_path *path;
5129         int ret = 0, depth;
5130         struct ext4_extent *extent;
5131         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5132         ext4_lblk_t tmp = EXT_MAX_BLOCKS;
5133
5134         /* Let path point to the last extent */
5135         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5136                                 EXT4_EX_NOCACHE);
5137         if (IS_ERR(path))
5138                 return PTR_ERR(path);
5139
5140         depth = path->p_depth;
5141         extent = path[depth].p_ext;
5142         if (!extent)
5143                 goto out;
5144
5145         stop = le32_to_cpu(extent->ee_block);
5146
5147        /*
5148         * For left shifts, make sure the hole on the left is big enough to
5149         * accommodate the shift.  For right shifts, make sure the last extent
5150         * won't be shifted beyond EXT_MAX_BLOCKS.
5151         */
5152         if (SHIFT == SHIFT_LEFT) {
5153                 path = ext4_find_extent(inode, start - 1, &path,
5154                                         EXT4_EX_NOCACHE);
5155                 if (IS_ERR(path))
5156                         return PTR_ERR(path);
5157                 depth = path->p_depth;
5158                 extent =  path[depth].p_ext;
5159                 if (extent) {
5160                         ex_start = le32_to_cpu(extent->ee_block);
5161                         ex_end = le32_to_cpu(extent->ee_block) +
5162                                 ext4_ext_get_actual_len(extent);
5163                 } else {
5164                         ex_start = 0;
5165                         ex_end = 0;
5166                 }
5167
5168                 if ((start == ex_start && shift > ex_start) ||
5169                     (shift > start - ex_end)) {
5170                         ret = -EINVAL;
5171                         goto out;
5172                 }
5173         } else {
5174                 if (shift > EXT_MAX_BLOCKS -
5175                     (stop + ext4_ext_get_actual_len(extent))) {
5176                         ret = -EINVAL;
5177                         goto out;
5178                 }
5179         }
5180
5181         /*
5182          * In case of left shift, iterator points to start and it is increased
5183          * till we reach stop. In case of right shift, iterator points to stop
5184          * and it is decreased till we reach start.
5185          */
5186 again:
5187         ret = 0;
5188         if (SHIFT == SHIFT_LEFT)
5189                 iterator = &start;
5190         else
5191                 iterator = &stop;
5192
5193         if (tmp != EXT_MAX_BLOCKS)
5194                 *iterator = tmp;
5195
5196         /*
5197          * Its safe to start updating extents.  Start and stop are unsigned, so
5198          * in case of right shift if extent with 0 block is reached, iterator
5199          * becomes NULL to indicate the end of the loop.
5200          */
5201         while (iterator && start <= stop) {
5202                 path = ext4_find_extent(inode, *iterator, &path,
5203                                         EXT4_EX_NOCACHE);
5204                 if (IS_ERR(path))
5205                         return PTR_ERR(path);
5206                 depth = path->p_depth;
5207                 extent = path[depth].p_ext;
5208                 if (!extent) {
5209                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5210                                          (unsigned long) *iterator);
5211                         return -EFSCORRUPTED;
5212                 }
5213                 if (SHIFT == SHIFT_LEFT && *iterator >
5214                     le32_to_cpu(extent->ee_block)) {
5215                         /* Hole, move to the next extent */
5216                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5217                                 path[depth].p_ext++;
5218                         } else {
5219                                 *iterator = ext4_ext_next_allocated_block(path);
5220                                 continue;
5221                         }
5222                 }
5223
5224                 tmp = *iterator;
5225                 if (SHIFT == SHIFT_LEFT) {
5226                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5227                         *iterator = le32_to_cpu(extent->ee_block) +
5228                                         ext4_ext_get_actual_len(extent);
5229                 } else {
5230                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5231                         if (le32_to_cpu(extent->ee_block) > start)
5232                                 *iterator = le32_to_cpu(extent->ee_block) - 1;
5233                         else if (le32_to_cpu(extent->ee_block) == start)
5234                                 iterator = NULL;
5235                         else {
5236                                 extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5237                                 while (le32_to_cpu(extent->ee_block) >= start)
5238                                         extent--;
5239
5240                                 if (extent == EXT_LAST_EXTENT(path[depth].p_hdr))
5241                                         break;
5242
5243                                 extent++;
5244                                 iterator = NULL;
5245                         }
5246                         path[depth].p_ext = extent;
5247                 }
5248                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5249                                 handle, SHIFT);
5250                 /* iterator can be NULL which means we should break */
5251                 if (ret == -EAGAIN)
5252                         goto again;
5253                 if (ret)
5254                         break;
5255         }
5256 out:
5257         ext4_free_ext_path(path);
5258         return ret;
5259 }
5260
5261 /*
5262  * ext4_collapse_range:
5263  * This implements the fallocate's collapse range functionality for ext4
5264  * Returns: 0 and non-zero on error.
5265  */
5266 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)
5267 {
5268         struct inode *inode = file_inode(file);
5269         struct super_block *sb = inode->i_sb;
5270         struct address_space *mapping = inode->i_mapping;
5271         ext4_lblk_t punch_start, punch_stop;
5272         handle_t *handle;
5273         unsigned int credits;
5274         loff_t new_size, ioffset;
5275         int ret;
5276
5277         /*
5278          * We need to test this early because xfstests assumes that a
5279          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5280          * system does not support collapse range.
5281          */
5282         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5283                 return -EOPNOTSUPP;
5284
5285         /* Collapse range works only on fs cluster size aligned regions. */
5286         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5287                 return -EINVAL;
5288
5289         trace_ext4_collapse_range(inode, offset, len);
5290
5291         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5292         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5293
5294         /* Call ext4_force_commit to flush all data in case of data=journal. */
5295         if (ext4_should_journal_data(inode)) {
5296                 ret = ext4_force_commit(inode->i_sb);
5297                 if (ret)
5298                         return ret;
5299         }
5300
5301         inode_lock(inode);
5302         /*
5303          * There is no need to overlap collapse range with EOF, in which case
5304          * it is effectively a truncate operation
5305          */
5306         if (offset + len >= inode->i_size) {
5307                 ret = -EINVAL;
5308                 goto out_mutex;
5309         }
5310
5311         /* Currently just for extent based files */
5312         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5313                 ret = -EOPNOTSUPP;
5314                 goto out_mutex;
5315         }
5316
5317         /* Wait for existing dio to complete */
5318         inode_dio_wait(inode);
5319
5320         ret = file_modified(file);
5321         if (ret)
5322                 goto out_mutex;
5323
5324         /*
5325          * Prevent page faults from reinstantiating pages we have released from
5326          * page cache.
5327          */
5328         filemap_invalidate_lock(mapping);
5329
5330         ret = ext4_break_layouts(inode);
5331         if (ret)
5332                 goto out_mmap;
5333
5334         /*
5335          * Need to round down offset to be aligned with page size boundary
5336          * for page size > block size.
5337          */
5338         ioffset = round_down(offset, PAGE_SIZE);
5339         /*
5340          * Write tail of the last page before removed range since it will get
5341          * removed from the page cache below.
5342          */
5343         ret = filemap_write_and_wait_range(mapping, ioffset, offset);
5344         if (ret)
5345                 goto out_mmap;
5346         /*
5347          * Write data that will be shifted to preserve them when discarding
5348          * page cache below. We are also protected from pages becoming dirty
5349          * by i_rwsem and invalidate_lock.
5350          */
5351         ret = filemap_write_and_wait_range(mapping, offset + len,
5352                                            LLONG_MAX);
5353         if (ret)
5354                 goto out_mmap;
5355         truncate_pagecache(inode, ioffset);
5356
5357         credits = ext4_writepage_trans_blocks(inode);
5358         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5359         if (IS_ERR(handle)) {
5360                 ret = PTR_ERR(handle);
5361                 goto out_mmap;
5362         }
5363         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5364
5365         down_write(&EXT4_I(inode)->i_data_sem);
5366         ext4_discard_preallocations(inode, 0);
5367
5368         ret = ext4_es_remove_extent(inode, punch_start,
5369                                     EXT_MAX_BLOCKS - punch_start);
5370         if (ret) {
5371                 up_write(&EXT4_I(inode)->i_data_sem);
5372                 goto out_stop;
5373         }
5374
5375         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5376         if (ret) {
5377                 up_write(&EXT4_I(inode)->i_data_sem);
5378                 goto out_stop;
5379         }
5380         ext4_discard_preallocations(inode, 0);
5381
5382         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5383                                      punch_stop - punch_start, SHIFT_LEFT);
5384         if (ret) {
5385                 up_write(&EXT4_I(inode)->i_data_sem);
5386                 goto out_stop;
5387         }
5388
5389         new_size = inode->i_size - len;
5390         i_size_write(inode, new_size);
5391         EXT4_I(inode)->i_disksize = new_size;
5392
5393         up_write(&EXT4_I(inode)->i_data_sem);
5394         if (IS_SYNC(inode))
5395                 ext4_handle_sync(handle);
5396         inode->i_mtime = inode->i_ctime = current_time(inode);
5397         ret = ext4_mark_inode_dirty(handle, inode);
5398         ext4_update_inode_fsync_trans(handle, inode, 1);
5399
5400 out_stop:
5401         ext4_journal_stop(handle);
5402 out_mmap:
5403         filemap_invalidate_unlock(mapping);
5404 out_mutex:
5405         inode_unlock(inode);
5406         return ret;
5407 }
5408
5409 /*
5410  * ext4_insert_range:
5411  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5412  * The data blocks starting from @offset to the EOF are shifted by @len
5413  * towards right to create a hole in the @inode. Inode size is increased
5414  * by len bytes.
5415  * Returns 0 on success, error otherwise.
5416  */
5417 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
5418 {
5419         struct inode *inode = file_inode(file);
5420         struct super_block *sb = inode->i_sb;
5421         struct address_space *mapping = inode->i_mapping;
5422         handle_t *handle;
5423         struct ext4_ext_path *path;
5424         struct ext4_extent *extent;
5425         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5426         unsigned int credits, ee_len;
5427         int ret = 0, depth, split_flag = 0;
5428         loff_t ioffset;
5429
5430         /*
5431          * We need to test this early because xfstests assumes that an
5432          * insert range of (0, 1) will return EOPNOTSUPP if the file
5433          * system does not support insert range.
5434          */
5435         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5436                 return -EOPNOTSUPP;
5437
5438         /* Insert range works only on fs cluster size aligned regions. */
5439         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5440                 return -EINVAL;
5441
5442         trace_ext4_insert_range(inode, offset, len);
5443
5444         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5445         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5446
5447         /* Call ext4_force_commit to flush all data in case of data=journal */
5448         if (ext4_should_journal_data(inode)) {
5449                 ret = ext4_force_commit(inode->i_sb);
5450                 if (ret)
5451                         return ret;
5452         }
5453
5454         inode_lock(inode);
5455         /* Currently just for extent based files */
5456         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5457                 ret = -EOPNOTSUPP;
5458                 goto out_mutex;
5459         }
5460
5461         /* Check whether the maximum file size would be exceeded */
5462         if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5463                 ret = -EFBIG;
5464                 goto out_mutex;
5465         }
5466
5467         /* Offset must be less than i_size */
5468         if (offset >= inode->i_size) {
5469                 ret = -EINVAL;
5470                 goto out_mutex;
5471         }
5472
5473         /* Wait for existing dio to complete */
5474         inode_dio_wait(inode);
5475
5476         ret = file_modified(file);
5477         if (ret)
5478                 goto out_mutex;
5479
5480         /*
5481          * Prevent page faults from reinstantiating pages we have released from
5482          * page cache.
5483          */
5484         filemap_invalidate_lock(mapping);
5485
5486         ret = ext4_break_layouts(inode);
5487         if (ret)
5488                 goto out_mmap;
5489
5490         /*
5491          * Need to round down to align start offset to page size boundary
5492          * for page size > block size.
5493          */
5494         ioffset = round_down(offset, PAGE_SIZE);
5495         /* Write out all dirty pages */
5496         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5497                         LLONG_MAX);
5498         if (ret)
5499                 goto out_mmap;
5500         truncate_pagecache(inode, ioffset);
5501
5502         credits = ext4_writepage_trans_blocks(inode);
5503         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5504         if (IS_ERR(handle)) {
5505                 ret = PTR_ERR(handle);
5506                 goto out_mmap;
5507         }
5508         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5509
5510         /* Expand file to avoid data loss if there is error while shifting */
5511         inode->i_size += len;
5512         EXT4_I(inode)->i_disksize += len;
5513         inode->i_mtime = inode->i_ctime = current_time(inode);
5514         ret = ext4_mark_inode_dirty(handle, inode);
5515         if (ret)
5516                 goto out_stop;
5517
5518         down_write(&EXT4_I(inode)->i_data_sem);
5519         ext4_discard_preallocations(inode, 0);
5520
5521         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5522         if (IS_ERR(path)) {
5523                 up_write(&EXT4_I(inode)->i_data_sem);
5524                 goto out_stop;
5525         }
5526
5527         depth = ext_depth(inode);
5528         extent = path[depth].p_ext;
5529         if (extent) {
5530                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5531                 ee_len = ext4_ext_get_actual_len(extent);
5532
5533                 /*
5534                  * If offset_lblk is not the starting block of extent, split
5535                  * the extent @offset_lblk
5536                  */
5537                 if ((offset_lblk > ee_start_lblk) &&
5538                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5539                         if (ext4_ext_is_unwritten(extent))
5540                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5541                                         EXT4_EXT_MARK_UNWRIT2;
5542                         ret = ext4_split_extent_at(handle, inode, &path,
5543                                         offset_lblk, split_flag,
5544                                         EXT4_EX_NOCACHE |
5545                                         EXT4_GET_BLOCKS_PRE_IO |
5546                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5547                 }
5548
5549                 ext4_free_ext_path(path);
5550                 if (ret < 0) {
5551                         up_write(&EXT4_I(inode)->i_data_sem);
5552                         goto out_stop;
5553                 }
5554         } else {
5555                 ext4_free_ext_path(path);
5556         }
5557
5558         ret = ext4_es_remove_extent(inode, offset_lblk,
5559                         EXT_MAX_BLOCKS - offset_lblk);
5560         if (ret) {
5561                 up_write(&EXT4_I(inode)->i_data_sem);
5562                 goto out_stop;
5563         }
5564
5565         /*
5566          * if offset_lblk lies in a hole which is at start of file, use
5567          * ee_start_lblk to shift extents
5568          */
5569         ret = ext4_ext_shift_extents(inode, handle,
5570                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5571                 len_lblk, SHIFT_RIGHT);
5572
5573         up_write(&EXT4_I(inode)->i_data_sem);
5574         if (IS_SYNC(inode))
5575                 ext4_handle_sync(handle);
5576         if (ret >= 0)
5577                 ext4_update_inode_fsync_trans(handle, inode, 1);
5578
5579 out_stop:
5580         ext4_journal_stop(handle);
5581 out_mmap:
5582         filemap_invalidate_unlock(mapping);
5583 out_mutex:
5584         inode_unlock(inode);
5585         return ret;
5586 }
5587
5588 /**
5589  * ext4_swap_extents() - Swap extents between two inodes
5590  * @handle: handle for this transaction
5591  * @inode1:     First inode
5592  * @inode2:     Second inode
5593  * @lblk1:      Start block for first inode
5594  * @lblk2:      Start block for second inode
5595  * @count:      Number of blocks to swap
5596  * @unwritten: Mark second inode's extents as unwritten after swap
5597  * @erp:        Pointer to save error value
5598  *
5599  * This helper routine does exactly what is promise "swap extents". All other
5600  * stuff such as page-cache locking consistency, bh mapping consistency or
5601  * extent's data copying must be performed by caller.
5602  * Locking:
5603  *              i_rwsem is held for both inodes
5604  *              i_data_sem is locked for write for both inodes
5605  * Assumptions:
5606  *              All pages from requested range are locked for both inodes
5607  */
5608 int
5609 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5610                   struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5611                   ext4_lblk_t count, int unwritten, int *erp)
5612 {
5613         struct ext4_ext_path *path1 = NULL;
5614         struct ext4_ext_path *path2 = NULL;
5615         int replaced_count = 0;
5616
5617         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5618         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5619         BUG_ON(!inode_is_locked(inode1));
5620         BUG_ON(!inode_is_locked(inode2));
5621
5622         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5623         if (unlikely(*erp))
5624                 return 0;
5625         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5626         if (unlikely(*erp))
5627                 return 0;
5628
5629         while (count) {
5630                 struct ext4_extent *ex1, *ex2, tmp_ex;
5631                 ext4_lblk_t e1_blk, e2_blk;
5632                 int e1_len, e2_len, len;
5633                 int split = 0;
5634
5635                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5636                 if (IS_ERR(path1)) {
5637                         *erp = PTR_ERR(path1);
5638                         path1 = NULL;
5639                 finish:
5640                         count = 0;
5641                         goto repeat;
5642                 }
5643                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5644                 if (IS_ERR(path2)) {
5645                         *erp = PTR_ERR(path2);
5646                         path2 = NULL;
5647                         goto finish;
5648                 }
5649                 ex1 = path1[path1->p_depth].p_ext;
5650                 ex2 = path2[path2->p_depth].p_ext;
5651                 /* Do we have something to swap ? */
5652                 if (unlikely(!ex2 || !ex1))
5653                         goto finish;
5654
5655                 e1_blk = le32_to_cpu(ex1->ee_block);
5656                 e2_blk = le32_to_cpu(ex2->ee_block);
5657                 e1_len = ext4_ext_get_actual_len(ex1);
5658                 e2_len = ext4_ext_get_actual_len(ex2);
5659
5660                 /* Hole handling */
5661                 if (!in_range(lblk1, e1_blk, e1_len) ||
5662                     !in_range(lblk2, e2_blk, e2_len)) {
5663                         ext4_lblk_t next1, next2;
5664
5665                         /* if hole after extent, then go to next extent */
5666                         next1 = ext4_ext_next_allocated_block(path1);
5667                         next2 = ext4_ext_next_allocated_block(path2);
5668                         /* If hole before extent, then shift to that extent */
5669                         if (e1_blk > lblk1)
5670                                 next1 = e1_blk;
5671                         if (e2_blk > lblk2)
5672                                 next2 = e2_blk;
5673                         /* Do we have something to swap */
5674                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5675                                 goto finish;
5676                         /* Move to the rightest boundary */
5677                         len = next1 - lblk1;
5678                         if (len < next2 - lblk2)
5679                                 len = next2 - lblk2;
5680                         if (len > count)
5681                                 len = count;
5682                         lblk1 += len;
5683                         lblk2 += len;
5684                         count -= len;
5685                         goto repeat;
5686                 }
5687
5688                 /* Prepare left boundary */
5689                 if (e1_blk < lblk1) {
5690                         split = 1;
5691                         *erp = ext4_force_split_extent_at(handle, inode1,
5692                                                 &path1, lblk1, 0);
5693                         if (unlikely(*erp))
5694                                 goto finish;
5695                 }
5696                 if (e2_blk < lblk2) {
5697                         split = 1;
5698                         *erp = ext4_force_split_extent_at(handle, inode2,
5699                                                 &path2,  lblk2, 0);
5700                         if (unlikely(*erp))
5701                                 goto finish;
5702                 }
5703                 /* ext4_split_extent_at() may result in leaf extent split,
5704                  * path must to be revalidated. */
5705                 if (split)
5706                         goto repeat;
5707
5708                 /* Prepare right boundary */
5709                 len = count;
5710                 if (len > e1_blk + e1_len - lblk1)
5711                         len = e1_blk + e1_len - lblk1;
5712                 if (len > e2_blk + e2_len - lblk2)
5713                         len = e2_blk + e2_len - lblk2;
5714
5715                 if (len != e1_len) {
5716                         split = 1;
5717                         *erp = ext4_force_split_extent_at(handle, inode1,
5718                                                 &path1, lblk1 + len, 0);
5719                         if (unlikely(*erp))
5720                                 goto finish;
5721                 }
5722                 if (len != e2_len) {
5723                         split = 1;
5724                         *erp = ext4_force_split_extent_at(handle, inode2,
5725                                                 &path2, lblk2 + len, 0);
5726                         if (*erp)
5727                                 goto finish;
5728                 }
5729                 /* ext4_split_extent_at() may result in leaf extent split,
5730                  * path must to be revalidated. */
5731                 if (split)
5732                         goto repeat;
5733
5734                 BUG_ON(e2_len != e1_len);
5735                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5736                 if (unlikely(*erp))
5737                         goto finish;
5738                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5739                 if (unlikely(*erp))
5740                         goto finish;
5741
5742                 /* Both extents are fully inside boundaries. Swap it now */
5743                 tmp_ex = *ex1;
5744                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5745                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5746                 ex1->ee_len = cpu_to_le16(e2_len);
5747                 ex2->ee_len = cpu_to_le16(e1_len);
5748                 if (unwritten)
5749                         ext4_ext_mark_unwritten(ex2);
5750                 if (ext4_ext_is_unwritten(&tmp_ex))
5751                         ext4_ext_mark_unwritten(ex1);
5752
5753                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5754                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5755                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5756                                       path2->p_depth);
5757                 if (unlikely(*erp))
5758                         goto finish;
5759                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5760                                       path1->p_depth);
5761                 /*
5762                  * Looks scarry ah..? second inode already points to new blocks,
5763                  * and it was successfully dirtied. But luckily error may happen
5764                  * only due to journal error, so full transaction will be
5765                  * aborted anyway.
5766                  */
5767                 if (unlikely(*erp))
5768                         goto finish;
5769                 lblk1 += len;
5770                 lblk2 += len;
5771                 replaced_count += len;
5772                 count -= len;
5773
5774         repeat:
5775                 ext4_free_ext_path(path1);
5776                 ext4_free_ext_path(path2);
5777                 path1 = path2 = NULL;
5778         }
5779         return replaced_count;
5780 }
5781
5782 /*
5783  * ext4_clu_mapped - determine whether any block in a logical cluster has
5784  *                   been mapped to a physical cluster
5785  *
5786  * @inode - file containing the logical cluster
5787  * @lclu - logical cluster of interest
5788  *
5789  * Returns 1 if any block in the logical cluster is mapped, signifying
5790  * that a physical cluster has been allocated for it.  Otherwise,
5791  * returns 0.  Can also return negative error codes.  Derived from
5792  * ext4_ext_map_blocks().
5793  */
5794 int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5795 {
5796         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5797         struct ext4_ext_path *path;
5798         int depth, mapped = 0, err = 0;
5799         struct ext4_extent *extent;
5800         ext4_lblk_t first_lblk, first_lclu, last_lclu;
5801
5802         /*
5803          * if data can be stored inline, the logical cluster isn't
5804          * mapped - no physical clusters have been allocated, and the
5805          * file has no extents
5806          */
5807         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))
5808                 return 0;
5809
5810         /* search for the extent closest to the first block in the cluster */
5811         path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5812         if (IS_ERR(path)) {
5813                 err = PTR_ERR(path);
5814                 path = NULL;
5815                 goto out;
5816         }
5817
5818         depth = ext_depth(inode);
5819
5820         /*
5821          * A consistent leaf must not be empty.  This situation is possible,
5822          * though, _during_ tree modification, and it's why an assert can't
5823          * be put in ext4_find_extent().
5824          */
5825         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5826                 EXT4_ERROR_INODE(inode,
5827                     "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5828                                  (unsigned long) EXT4_C2B(sbi, lclu),
5829                                  depth, path[depth].p_block);
5830                 err = -EFSCORRUPTED;
5831                 goto out;
5832         }
5833
5834         extent = path[depth].p_ext;
5835
5836         /* can't be mapped if the extent tree is empty */
5837         if (extent == NULL)
5838                 goto out;
5839
5840         first_lblk = le32_to_cpu(extent->ee_block);
5841         first_lclu = EXT4_B2C(sbi, first_lblk);
5842
5843         /*
5844          * Three possible outcomes at this point - found extent spanning
5845          * the target cluster, to the left of the target cluster, or to the
5846          * right of the target cluster.  The first two cases are handled here.
5847          * The last case indicates the target cluster is not mapped.
5848          */
5849         if (lclu >= first_lclu) {
5850                 last_lclu = EXT4_B2C(sbi, first_lblk +
5851                                      ext4_ext_get_actual_len(extent) - 1);
5852                 if (lclu <= last_lclu) {
5853                         mapped = 1;
5854                 } else {
5855                         first_lblk = ext4_ext_next_allocated_block(path);
5856                         first_lclu = EXT4_B2C(sbi, first_lblk);
5857                         if (lclu == first_lclu)
5858                                 mapped = 1;
5859                 }
5860         }
5861
5862 out:
5863         ext4_free_ext_path(path);
5864
5865         return err ? err : mapped;
5866 }
5867
5868 /*
5869  * Updates physical block address and unwritten status of extent
5870  * starting at lblk start and of len. If such an extent doesn't exist,
5871  * this function splits the extent tree appropriately to create an
5872  * extent like this.  This function is called in the fast commit
5873  * replay path.  Returns 0 on success and error on failure.
5874  */
5875 int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
5876                               int len, int unwritten, ext4_fsblk_t pblk)
5877 {
5878         struct ext4_ext_path *path = NULL, *ppath;
5879         struct ext4_extent *ex;
5880         int ret;
5881
5882         path = ext4_find_extent(inode, start, NULL, 0);
5883         if (IS_ERR(path))
5884                 return PTR_ERR(path);
5885         ex = path[path->p_depth].p_ext;
5886         if (!ex) {
5887                 ret = -EFSCORRUPTED;
5888                 goto out;
5889         }
5890
5891         if (le32_to_cpu(ex->ee_block) != start ||
5892                 ext4_ext_get_actual_len(ex) != len) {
5893                 /* We need to split this extent to match our extent first */
5894                 ppath = path;
5895                 down_write(&EXT4_I(inode)->i_data_sem);
5896                 ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
5897                 up_write(&EXT4_I(inode)->i_data_sem);
5898                 if (ret)
5899                         goto out;
5900                 kfree(path);
5901                 path = ext4_find_extent(inode, start, NULL, 0);
5902                 if (IS_ERR(path))
5903                         return -1;
5904                 ppath = path;
5905                 ex = path[path->p_depth].p_ext;
5906                 WARN_ON(le32_to_cpu(ex->ee_block) != start);
5907                 if (ext4_ext_get_actual_len(ex) != len) {
5908                         down_write(&EXT4_I(inode)->i_data_sem);
5909                         ret = ext4_force_split_extent_at(NULL, inode, &ppath,
5910                                                          start + len, 1);
5911                         up_write(&EXT4_I(inode)->i_data_sem);
5912                         if (ret)
5913                                 goto out;
5914                         kfree(path);
5915                         path = ext4_find_extent(inode, start, NULL, 0);
5916                         if (IS_ERR(path))
5917                                 return -EINVAL;
5918                         ex = path[path->p_depth].p_ext;
5919                 }
5920         }
5921         if (unwritten)
5922                 ext4_ext_mark_unwritten(ex);
5923         else
5924                 ext4_ext_mark_initialized(ex);
5925         ext4_ext_store_pblock(ex, pblk);
5926         down_write(&EXT4_I(inode)->i_data_sem);
5927         ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5928         up_write(&EXT4_I(inode)->i_data_sem);
5929 out:
5930         ext4_free_ext_path(path);
5931         ext4_mark_inode_dirty(NULL, inode);
5932         return ret;
5933 }
5934
5935 /* Try to shrink the extent tree */
5936 void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
5937 {
5938         struct ext4_ext_path *path = NULL;
5939         struct ext4_extent *ex;
5940         ext4_lblk_t old_cur, cur = 0;
5941
5942         while (cur < end) {
5943                 path = ext4_find_extent(inode, cur, NULL, 0);
5944                 if (IS_ERR(path))
5945                         return;
5946                 ex = path[path->p_depth].p_ext;
5947                 if (!ex) {
5948                         ext4_free_ext_path(path);
5949                         ext4_mark_inode_dirty(NULL, inode);
5950                         return;
5951                 }
5952                 old_cur = cur;
5953                 cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5954                 if (cur <= old_cur)
5955                         cur = old_cur + 1;
5956                 ext4_ext_try_to_merge(NULL, inode, path, ex);
5957                 down_write(&EXT4_I(inode)->i_data_sem);
5958                 ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5959                 up_write(&EXT4_I(inode)->i_data_sem);
5960                 ext4_mark_inode_dirty(NULL, inode);
5961                 ext4_free_ext_path(path);
5962         }
5963 }
5964
5965 /* Check if *cur is a hole and if it is, skip it */
5966 static int skip_hole(struct inode *inode, ext4_lblk_t *cur)
5967 {
5968         int ret;
5969         struct ext4_map_blocks map;
5970
5971         map.m_lblk = *cur;
5972         map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
5973
5974         ret = ext4_map_blocks(NULL, inode, &map, 0);
5975         if (ret < 0)
5976                 return ret;
5977         if (ret != 0)
5978                 return 0;
5979         *cur = *cur + map.m_len;
5980         return 0;
5981 }
5982
5983 /* Count number of blocks used by this inode and update i_blocks */
5984 int ext4_ext_replay_set_iblocks(struct inode *inode)
5985 {
5986         struct ext4_ext_path *path = NULL, *path2 = NULL;
5987         struct ext4_extent *ex;
5988         ext4_lblk_t cur = 0, end;
5989         int numblks = 0, i, ret = 0;
5990         ext4_fsblk_t cmp1, cmp2;
5991         struct ext4_map_blocks map;
5992
5993         /* Determin the size of the file first */
5994         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5995                                         EXT4_EX_NOCACHE);
5996         if (IS_ERR(path))
5997                 return PTR_ERR(path);
5998         ex = path[path->p_depth].p_ext;
5999         if (!ex) {
6000                 ext4_free_ext_path(path);
6001                 goto out;
6002         }
6003         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6004         ext4_free_ext_path(path);
6005
6006         /* Count the number of data blocks */
6007         cur = 0;
6008         while (cur < end) {
6009                 map.m_lblk = cur;
6010                 map.m_len = end - cur;
6011                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6012                 if (ret < 0)
6013                         break;
6014                 if (ret > 0)
6015                         numblks += ret;
6016                 cur = cur + map.m_len;
6017         }
6018
6019         /*
6020          * Count the number of extent tree blocks. We do it by looking up
6021          * two successive extents and determining the difference between
6022          * their paths. When path is different for 2 successive extents
6023          * we compare the blocks in the path at each level and increment
6024          * iblocks by total number of differences found.
6025          */
6026         cur = 0;
6027         ret = skip_hole(inode, &cur);
6028         if (ret < 0)
6029                 goto out;
6030         path = ext4_find_extent(inode, cur, NULL, 0);
6031         if (IS_ERR(path))
6032                 goto out;
6033         numblks += path->p_depth;
6034         ext4_free_ext_path(path);
6035         while (cur < end) {
6036                 path = ext4_find_extent(inode, cur, NULL, 0);
6037                 if (IS_ERR(path))
6038                         break;
6039                 ex = path[path->p_depth].p_ext;
6040                 if (!ex) {
6041                         ext4_free_ext_path(path);
6042                         return 0;
6043                 }
6044                 cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
6045                                         ext4_ext_get_actual_len(ex));
6046                 ret = skip_hole(inode, &cur);
6047                 if (ret < 0) {
6048                         ext4_free_ext_path(path);
6049                         break;
6050                 }
6051                 path2 = ext4_find_extent(inode, cur, NULL, 0);
6052                 if (IS_ERR(path2)) {
6053                         ext4_free_ext_path(path);
6054                         break;
6055                 }
6056                 for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
6057                         cmp1 = cmp2 = 0;
6058                         if (i <= path->p_depth)
6059                                 cmp1 = path[i].p_bh ?
6060                                         path[i].p_bh->b_blocknr : 0;
6061                         if (i <= path2->p_depth)
6062                                 cmp2 = path2[i].p_bh ?
6063                                         path2[i].p_bh->b_blocknr : 0;
6064                         if (cmp1 != cmp2 && cmp2 != 0)
6065                                 numblks++;
6066                 }
6067                 ext4_free_ext_path(path);
6068                 ext4_free_ext_path(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_free_ext_path(path);
6096                 return 0;
6097         }
6098         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6099         ext4_free_ext_path(path);
6100
6101         cur = 0;
6102         while (cur < end) {
6103                 map.m_lblk = cur;
6104                 map.m_len = end - cur;
6105                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6106                 if (ret < 0)
6107                         break;
6108                 if (ret > 0) {
6109                         path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
6110                         if (!IS_ERR_OR_NULL(path)) {
6111                                 for (j = 0; j < path->p_depth; j++) {
6112
6113                                         ext4_mb_mark_bb(inode->i_sb,
6114                                                         path[j].p_block, 1, 0);
6115                                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6116                                                         0, path[j].p_block, 1, 1);
6117                                 }
6118                                 ext4_free_ext_path(path);
6119                         }
6120                         ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
6121                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6122                                         map.m_lblk, map.m_pblk, map.m_len, 1);
6123                 }
6124                 cur = cur + map.m_len;
6125         }
6126
6127         return 0;
6128 }