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         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
1014                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1015                 return -EFSCORRUPTED;
1016         }
1017
1018         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
1019         BUG_ON(len < 0);
1020         if (len > 0) {
1021                 ext_debug(inode, "insert new index %d: "
1022                                 "move %d indices from 0x%p to 0x%p\n",
1023                                 logical, len, ix, ix + 1);
1024                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
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_find_hole - find hole around given block according to the given path
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_find_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_rm_idx:
2275  * removes index from the index block.
2276  */
2277 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2278                         struct ext4_ext_path *path, int depth)
2279 {
2280         int err;
2281         ext4_fsblk_t leaf;
2282
2283         /* free index block */
2284         depth--;
2285         path = path + depth;
2286         leaf = ext4_idx_pblock(path->p_idx);
2287         if (unlikely(path->p_hdr->eh_entries == 0)) {
2288                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2289                 return -EFSCORRUPTED;
2290         }
2291         err = ext4_ext_get_access(handle, inode, path);
2292         if (err)
2293                 return err;
2294
2295         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2296                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2297                 len *= sizeof(struct ext4_extent_idx);
2298                 memmove(path->p_idx, path->p_idx + 1, len);
2299         }
2300
2301         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2302         err = ext4_ext_dirty(handle, inode, path);
2303         if (err)
2304                 return err;
2305         ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
2306         trace_ext4_ext_rm_idx(inode, leaf);
2307
2308         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2309                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2310
2311         while (--depth >= 0) {
2312                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2313                         break;
2314                 path--;
2315                 err = ext4_ext_get_access(handle, inode, path);
2316                 if (err)
2317                         break;
2318                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2319                 err = ext4_ext_dirty(handle, inode, path);
2320                 if (err)
2321                         break;
2322         }
2323         return err;
2324 }
2325
2326 /*
2327  * ext4_ext_calc_credits_for_single_extent:
2328  * This routine returns max. credits that needed to insert an extent
2329  * to the extent tree.
2330  * When pass the actual path, the caller should calculate credits
2331  * under i_data_sem.
2332  */
2333 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2334                                                 struct ext4_ext_path *path)
2335 {
2336         if (path) {
2337                 int depth = ext_depth(inode);
2338                 int ret = 0;
2339
2340                 /* probably there is space in leaf? */
2341                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2342                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2343
2344                         /*
2345                          *  There are some space in the leaf tree, no
2346                          *  need to account for leaf block credit
2347                          *
2348                          *  bitmaps and block group descriptor blocks
2349                          *  and other metadata blocks still need to be
2350                          *  accounted.
2351                          */
2352                         /* 1 bitmap, 1 block group descriptor */
2353                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2354                         return ret;
2355                 }
2356         }
2357
2358         return ext4_chunk_trans_blocks(inode, nrblocks);
2359 }
2360
2361 /*
2362  * How many index/leaf blocks need to change/allocate to add @extents extents?
2363  *
2364  * If we add a single extent, then in the worse case, each tree level
2365  * index/leaf need to be changed in case of the tree split.
2366  *
2367  * If more extents are inserted, they could cause the whole tree split more
2368  * than once, but this is really rare.
2369  */
2370 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2371 {
2372         int index;
2373         int depth;
2374
2375         /* If we are converting the inline data, only one is needed here. */
2376         if (ext4_has_inline_data(inode))
2377                 return 1;
2378
2379         depth = ext_depth(inode);
2380
2381         if (extents <= 1)
2382                 index = depth * 2;
2383         else
2384                 index = depth * 3;
2385
2386         return index;
2387 }
2388
2389 static inline int get_default_free_blocks_flags(struct inode *inode)
2390 {
2391         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2392             ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2393                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2394         else if (ext4_should_journal_data(inode))
2395                 return EXT4_FREE_BLOCKS_FORGET;
2396         return 0;
2397 }
2398
2399 /*
2400  * ext4_rereserve_cluster - increment the reserved cluster count when
2401  *                          freeing a cluster with a pending reservation
2402  *
2403  * @inode - file containing the cluster
2404  * @lblk - logical block in cluster to be reserved
2405  *
2406  * Increments the reserved cluster count and adjusts quota in a bigalloc
2407  * file system when freeing a partial cluster containing at least one
2408  * delayed and unwritten block.  A partial cluster meeting that
2409  * requirement will have a pending reservation.  If so, the
2410  * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2411  * defer reserved and allocated space accounting to a subsequent call
2412  * to this function.
2413  */
2414 static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2415 {
2416         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2417         struct ext4_inode_info *ei = EXT4_I(inode);
2418
2419         dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2420
2421         spin_lock(&ei->i_block_reservation_lock);
2422         ei->i_reserved_data_blocks++;
2423         percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2424         spin_unlock(&ei->i_block_reservation_lock);
2425
2426         percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2427         ext4_remove_pending(inode, lblk);
2428 }
2429
2430 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2431                               struct ext4_extent *ex,
2432                               struct partial_cluster *partial,
2433                               ext4_lblk_t from, ext4_lblk_t to)
2434 {
2435         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2436         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2437         ext4_fsblk_t last_pblk, pblk;
2438         ext4_lblk_t num;
2439         int flags;
2440
2441         /* only extent tail removal is allowed */
2442         if (from < le32_to_cpu(ex->ee_block) ||
2443             to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2444                 ext4_error(sbi->s_sb,
2445                            "strange request: removal(2) %u-%u from %u:%u",
2446                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2447                 return 0;
2448         }
2449
2450 #ifdef EXTENTS_STATS
2451         spin_lock(&sbi->s_ext_stats_lock);
2452         sbi->s_ext_blocks += ee_len;
2453         sbi->s_ext_extents++;
2454         if (ee_len < sbi->s_ext_min)
2455                 sbi->s_ext_min = ee_len;
2456         if (ee_len > sbi->s_ext_max)
2457                 sbi->s_ext_max = ee_len;
2458         if (ext_depth(inode) > sbi->s_depth_max)
2459                 sbi->s_depth_max = ext_depth(inode);
2460         spin_unlock(&sbi->s_ext_stats_lock);
2461 #endif
2462
2463         trace_ext4_remove_blocks(inode, ex, from, to, partial);
2464
2465         /*
2466          * if we have a partial cluster, and it's different from the
2467          * cluster of the last block in the extent, we free it
2468          */
2469         last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2470
2471         if (partial->state != initial &&
2472             partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2473                 if (partial->state == tofree) {
2474                         flags = get_default_free_blocks_flags(inode);
2475                         if (ext4_is_pending(inode, partial->lblk))
2476                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2477                         ext4_free_blocks(handle, inode, NULL,
2478                                          EXT4_C2B(sbi, partial->pclu),
2479                                          sbi->s_cluster_ratio, flags);
2480                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2481                                 ext4_rereserve_cluster(inode, partial->lblk);
2482                 }
2483                 partial->state = initial;
2484         }
2485
2486         num = le32_to_cpu(ex->ee_block) + ee_len - from;
2487         pblk = ext4_ext_pblock(ex) + ee_len - num;
2488
2489         /*
2490          * We free the partial cluster at the end of the extent (if any),
2491          * unless the cluster is used by another extent (partial_cluster
2492          * state is nofree).  If a partial cluster exists here, it must be
2493          * shared with the last block in the extent.
2494          */
2495         flags = get_default_free_blocks_flags(inode);
2496
2497         /* partial, left end cluster aligned, right end unaligned */
2498         if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2499             (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2500             (partial->state != nofree)) {
2501                 if (ext4_is_pending(inode, to))
2502                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2503                 ext4_free_blocks(handle, inode, NULL,
2504                                  EXT4_PBLK_CMASK(sbi, last_pblk),
2505                                  sbi->s_cluster_ratio, flags);
2506                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2507                         ext4_rereserve_cluster(inode, to);
2508                 partial->state = initial;
2509                 flags = get_default_free_blocks_flags(inode);
2510         }
2511
2512         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2513
2514         /*
2515          * For bigalloc file systems, we never free a partial cluster
2516          * at the beginning of the extent.  Instead, we check to see if we
2517          * need to free it on a subsequent call to ext4_remove_blocks,
2518          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2519          */
2520         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2521         ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2522
2523         /* reset the partial cluster if we've freed past it */
2524         if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2525                 partial->state = initial;
2526
2527         /*
2528          * If we've freed the entire extent but the beginning is not left
2529          * cluster aligned and is not marked as ineligible for freeing we
2530          * record the partial cluster at the beginning of the extent.  It
2531          * wasn't freed by the preceding ext4_free_blocks() call, and we
2532          * need to look farther to the left to determine if it's to be freed
2533          * (not shared with another extent). Else, reset the partial
2534          * cluster - we're either  done freeing or the beginning of the
2535          * extent is left cluster aligned.
2536          */
2537         if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2538                 if (partial->state == initial) {
2539                         partial->pclu = EXT4_B2C(sbi, pblk);
2540                         partial->lblk = from;
2541                         partial->state = tofree;
2542                 }
2543         } else {
2544                 partial->state = initial;
2545         }
2546
2547         return 0;
2548 }
2549
2550 /*
2551  * ext4_ext_rm_leaf() Removes the extents associated with the
2552  * blocks appearing between "start" and "end".  Both "start"
2553  * and "end" must appear in the same extent or EIO is returned.
2554  *
2555  * @handle: The journal handle
2556  * @inode:  The files inode
2557  * @path:   The path to the leaf
2558  * @partial_cluster: The cluster which we'll have to free if all extents
2559  *                   has been released from it.  However, if this value is
2560  *                   negative, it's a cluster just to the right of the
2561  *                   punched region and it must not be freed.
2562  * @start:  The first block to remove
2563  * @end:   The last block to remove
2564  */
2565 static int
2566 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2567                  struct ext4_ext_path *path,
2568                  struct partial_cluster *partial,
2569                  ext4_lblk_t start, ext4_lblk_t end)
2570 {
2571         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2572         int err = 0, correct_index = 0;
2573         int depth = ext_depth(inode), credits, revoke_credits;
2574         struct ext4_extent_header *eh;
2575         ext4_lblk_t a, b;
2576         unsigned num;
2577         ext4_lblk_t ex_ee_block;
2578         unsigned short ex_ee_len;
2579         unsigned unwritten = 0;
2580         struct ext4_extent *ex;
2581         ext4_fsblk_t pblk;
2582
2583         /* the header must be checked already in ext4_ext_remove_space() */
2584         ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
2585         if (!path[depth].p_hdr)
2586                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2587         eh = path[depth].p_hdr;
2588         if (unlikely(path[depth].p_hdr == NULL)) {
2589                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2590                 return -EFSCORRUPTED;
2591         }
2592         /* find where to start removing */
2593         ex = path[depth].p_ext;
2594         if (!ex)
2595                 ex = EXT_LAST_EXTENT(eh);
2596
2597         ex_ee_block = le32_to_cpu(ex->ee_block);
2598         ex_ee_len = ext4_ext_get_actual_len(ex);
2599
2600         trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2601
2602         while (ex >= EXT_FIRST_EXTENT(eh) &&
2603                         ex_ee_block + ex_ee_len > start) {
2604
2605                 if (ext4_ext_is_unwritten(ex))
2606                         unwritten = 1;
2607                 else
2608                         unwritten = 0;
2609
2610                 ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
2611                           unwritten, ex_ee_len);
2612                 path[depth].p_ext = ex;
2613
2614                 a = ex_ee_block > start ? ex_ee_block : start;
2615                 b = ex_ee_block+ex_ee_len - 1 < end ?
2616                         ex_ee_block+ex_ee_len - 1 : end;
2617
2618                 ext_debug(inode, "  border %u:%u\n", a, b);
2619
2620                 /* If this extent is beyond the end of the hole, skip it */
2621                 if (end < ex_ee_block) {
2622                         /*
2623                          * We're going to skip this extent and move to another,
2624                          * so note that its first cluster is in use to avoid
2625                          * freeing it when removing blocks.  Eventually, the
2626                          * right edge of the truncated/punched region will
2627                          * be just to the left.
2628                          */
2629                         if (sbi->s_cluster_ratio > 1) {
2630                                 pblk = ext4_ext_pblock(ex);
2631                                 partial->pclu = EXT4_B2C(sbi, pblk);
2632                                 partial->state = nofree;
2633                         }
2634                         ex--;
2635                         ex_ee_block = le32_to_cpu(ex->ee_block);
2636                         ex_ee_len = ext4_ext_get_actual_len(ex);
2637                         continue;
2638                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2639                         EXT4_ERROR_INODE(inode,
2640                                          "can not handle truncate %u:%u "
2641                                          "on extent %u:%u",
2642                                          start, end, ex_ee_block,
2643                                          ex_ee_block + ex_ee_len - 1);
2644                         err = -EFSCORRUPTED;
2645                         goto out;
2646                 } else if (a != ex_ee_block) {
2647                         /* remove tail of the extent */
2648                         num = a - ex_ee_block;
2649                 } else {
2650                         /* remove whole extent: excellent! */
2651                         num = 0;
2652                 }
2653                 /*
2654                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2655                  * descriptor) for each block group; assume two block
2656                  * groups plus ex_ee_len/blocks_per_block_group for
2657                  * the worst case
2658                  */
2659                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2660                 if (ex == EXT_FIRST_EXTENT(eh)) {
2661                         correct_index = 1;
2662                         credits += (ext_depth(inode)) + 1;
2663                 }
2664                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2665                 /*
2666                  * We may end up freeing some index blocks and data from the
2667                  * punched range. Note that partial clusters are accounted for
2668                  * by ext4_free_data_revoke_credits().
2669                  */
2670                 revoke_credits =
2671                         ext4_free_metadata_revoke_credits(inode->i_sb,
2672                                                           ext_depth(inode)) +
2673                         ext4_free_data_revoke_credits(inode, b - a + 1);
2674
2675                 err = ext4_datasem_ensure_credits(handle, inode, credits,
2676                                                   credits, revoke_credits);
2677                 if (err) {
2678                         if (err > 0)
2679                                 err = -EAGAIN;
2680                         goto out;
2681                 }
2682
2683                 err = ext4_ext_get_access(handle, inode, path + depth);
2684                 if (err)
2685                         goto out;
2686
2687                 err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2688                 if (err)
2689                         goto out;
2690
2691                 if (num == 0)
2692                         /* this extent is removed; mark slot entirely unused */
2693                         ext4_ext_store_pblock(ex, 0);
2694
2695                 ex->ee_len = cpu_to_le16(num);
2696                 /*
2697                  * Do not mark unwritten if all the blocks in the
2698                  * extent have been removed.
2699                  */
2700                 if (unwritten && num)
2701                         ext4_ext_mark_unwritten(ex);
2702                 /*
2703                  * If the extent was completely released,
2704                  * we need to remove it from the leaf
2705                  */
2706                 if (num == 0) {
2707                         if (end != EXT_MAX_BLOCKS - 1) {
2708                                 /*
2709                                  * For hole punching, we need to scoot all the
2710                                  * extents up when an extent is removed so that
2711                                  * we dont have blank extents in the middle
2712                                  */
2713                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2714                                         sizeof(struct ext4_extent));
2715
2716                                 /* Now get rid of the one at the end */
2717                                 memset(EXT_LAST_EXTENT(eh), 0,
2718                                         sizeof(struct ext4_extent));
2719                         }
2720                         le16_add_cpu(&eh->eh_entries, -1);
2721                 }
2722
2723                 err = ext4_ext_dirty(handle, inode, path + depth);
2724                 if (err)
2725                         goto out;
2726
2727                 ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
2728                                 ext4_ext_pblock(ex));
2729                 ex--;
2730                 ex_ee_block = le32_to_cpu(ex->ee_block);
2731                 ex_ee_len = ext4_ext_get_actual_len(ex);
2732         }
2733
2734         if (correct_index && eh->eh_entries)
2735                 err = ext4_ext_correct_indexes(handle, inode, path);
2736
2737         /*
2738          * If there's a partial cluster and at least one extent remains in
2739          * the leaf, free the partial cluster if it isn't shared with the
2740          * current extent.  If it is shared with the current extent
2741          * we reset the partial cluster because we've reached the start of the
2742          * truncated/punched region and we're done removing blocks.
2743          */
2744         if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2745                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2746                 if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2747                         int flags = get_default_free_blocks_flags(inode);
2748
2749                         if (ext4_is_pending(inode, partial->lblk))
2750                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2751                         ext4_free_blocks(handle, inode, NULL,
2752                                          EXT4_C2B(sbi, partial->pclu),
2753                                          sbi->s_cluster_ratio, flags);
2754                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2755                                 ext4_rereserve_cluster(inode, partial->lblk);
2756                 }
2757                 partial->state = initial;
2758         }
2759
2760         /* if this leaf is free, then we should
2761          * remove it from index block above */
2762         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2763                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2764
2765 out:
2766         return err;
2767 }
2768
2769 /*
2770  * ext4_ext_more_to_rm:
2771  * returns 1 if current index has to be freed (even partial)
2772  */
2773 static int
2774 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2775 {
2776         BUG_ON(path->p_idx == NULL);
2777
2778         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2779                 return 0;
2780
2781         /*
2782          * if truncate on deeper level happened, it wasn't partial,
2783          * so we have to consider current index for truncation
2784          */
2785         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2786                 return 0;
2787         return 1;
2788 }
2789
2790 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2791                           ext4_lblk_t end)
2792 {
2793         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2794         int depth = ext_depth(inode);
2795         struct ext4_ext_path *path = NULL;
2796         struct partial_cluster partial;
2797         handle_t *handle;
2798         int i = 0, err = 0;
2799
2800         partial.pclu = 0;
2801         partial.lblk = 0;
2802         partial.state = initial;
2803
2804         ext_debug(inode, "truncate since %u to %u\n", start, end);
2805
2806         /* probably first extent we're gonna free will be last in block */
2807         handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2808                         depth + 1,
2809                         ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2810         if (IS_ERR(handle))
2811                 return PTR_ERR(handle);
2812
2813 again:
2814         trace_ext4_ext_remove_space(inode, start, end, depth);
2815
2816         /*
2817          * Check if we are removing extents inside the extent tree. If that
2818          * is the case, we are going to punch a hole inside the extent tree
2819          * so we have to check whether we need to split the extent covering
2820          * the last block to remove so we can easily remove the part of it
2821          * in ext4_ext_rm_leaf().
2822          */
2823         if (end < EXT_MAX_BLOCKS - 1) {
2824                 struct ext4_extent *ex;
2825                 ext4_lblk_t ee_block, ex_end, lblk;
2826                 ext4_fsblk_t pblk;
2827
2828                 /* find extent for or closest extent to this block */
2829                 path = ext4_find_extent(inode, end, NULL,
2830                                         EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
2831                 if (IS_ERR(path)) {
2832                         ext4_journal_stop(handle);
2833                         return PTR_ERR(path);
2834                 }
2835                 depth = ext_depth(inode);
2836                 /* Leaf not may not exist only if inode has no blocks at all */
2837                 ex = path[depth].p_ext;
2838                 if (!ex) {
2839                         if (depth) {
2840                                 EXT4_ERROR_INODE(inode,
2841                                                  "path[%d].p_hdr == NULL",
2842                                                  depth);
2843                                 err = -EFSCORRUPTED;
2844                         }
2845                         goto out;
2846                 }
2847
2848                 ee_block = le32_to_cpu(ex->ee_block);
2849                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2850
2851                 /*
2852                  * See if the last block is inside the extent, if so split
2853                  * the extent at 'end' block so we can easily remove the
2854                  * tail of the first part of the split extent in
2855                  * ext4_ext_rm_leaf().
2856                  */
2857                 if (end >= ee_block && end < ex_end) {
2858
2859                         /*
2860                          * If we're going to split the extent, note that
2861                          * the cluster containing the block after 'end' is
2862                          * in use to avoid freeing it when removing blocks.
2863                          */
2864                         if (sbi->s_cluster_ratio > 1) {
2865                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
2866                                 partial.pclu = EXT4_B2C(sbi, pblk);
2867                                 partial.state = nofree;
2868                         }
2869
2870                         /*
2871                          * Split the extent in two so that 'end' is the last
2872                          * block in the first new extent. Also we should not
2873                          * fail removing space due to ENOSPC so try to use
2874                          * reserved block if that happens.
2875                          */
2876                         err = ext4_force_split_extent_at(handle, inode, &path,
2877                                                          end + 1, 1);
2878                         if (err < 0)
2879                                 goto out;
2880
2881                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
2882                            partial.state == initial) {
2883                         /*
2884                          * If we're punching, there's an extent to the right.
2885                          * If the partial cluster hasn't been set, set it to
2886                          * that extent's first cluster and its state to nofree
2887                          * so it won't be freed should it contain blocks to be
2888                          * removed. If it's already set (tofree/nofree), we're
2889                          * retrying and keep the original partial cluster info
2890                          * so a cluster marked tofree as a result of earlier
2891                          * extent removal is not lost.
2892                          */
2893                         lblk = ex_end + 1;
2894                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2895                                                     NULL);
2896                         if (err < 0)
2897                                 goto out;
2898                         if (pblk) {
2899                                 partial.pclu = EXT4_B2C(sbi, pblk);
2900                                 partial.state = nofree;
2901                         }
2902                 }
2903         }
2904         /*
2905          * We start scanning from right side, freeing all the blocks
2906          * after i_size and walking into the tree depth-wise.
2907          */
2908         depth = ext_depth(inode);
2909         if (path) {
2910                 int k = i = depth;
2911                 while (--k > 0)
2912                         path[k].p_block =
2913                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2914         } else {
2915                 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
2916                                GFP_NOFS | __GFP_NOFAIL);
2917                 if (path == NULL) {
2918                         ext4_journal_stop(handle);
2919                         return -ENOMEM;
2920                 }
2921                 path[0].p_maxdepth = path[0].p_depth = depth;
2922                 path[0].p_hdr = ext_inode_hdr(inode);
2923                 i = 0;
2924
2925                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2926                         err = -EFSCORRUPTED;
2927                         goto out;
2928                 }
2929         }
2930         err = 0;
2931
2932         while (i >= 0 && err == 0) {
2933                 if (i == depth) {
2934                         /* this is leaf block */
2935                         err = ext4_ext_rm_leaf(handle, inode, path,
2936                                                &partial, start, end);
2937                         /* root level has p_bh == NULL, brelse() eats this */
2938                         brelse(path[i].p_bh);
2939                         path[i].p_bh = NULL;
2940                         i--;
2941                         continue;
2942                 }
2943
2944                 /* this is index block */
2945                 if (!path[i].p_hdr) {
2946                         ext_debug(inode, "initialize header\n");
2947                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2948                 }
2949
2950                 if (!path[i].p_idx) {
2951                         /* this level hasn't been touched yet */
2952                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2953                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2954                         ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
2955                                   path[i].p_hdr,
2956                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2957                 } else {
2958                         /* we were already here, see at next index */
2959                         path[i].p_idx--;
2960                 }
2961
2962                 ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
2963                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2964                                 path[i].p_idx);
2965                 if (ext4_ext_more_to_rm(path + i)) {
2966                         struct buffer_head *bh;
2967                         /* go to the next level */
2968                         ext_debug(inode, "move to level %d (block %llu)\n",
2969                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2970                         memset(path + i + 1, 0, sizeof(*path));
2971                         bh = read_extent_tree_block(inode, path[i].p_idx,
2972                                                     depth - i - 1,
2973                                                     EXT4_EX_NOCACHE);
2974                         if (IS_ERR(bh)) {
2975                                 /* should we reset i_size? */
2976                                 err = PTR_ERR(bh);
2977                                 break;
2978                         }
2979                         /* Yield here to deal with large extent trees.
2980                          * Should be a no-op if we did IO above. */
2981                         cond_resched();
2982                         if (WARN_ON(i + 1 > depth)) {
2983                                 err = -EFSCORRUPTED;
2984                                 break;
2985                         }
2986                         path[i + 1].p_bh = bh;
2987
2988                         /* save actual number of indexes since this
2989                          * number is changed at the next iteration */
2990                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2991                         i++;
2992                 } else {
2993                         /* we finished processing this index, go up */
2994                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2995                                 /* index is empty, remove it;
2996                                  * handle must be already prepared by the
2997                                  * truncatei_leaf() */
2998                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2999                         }
3000                         /* root level has p_bh == NULL, brelse() eats this */
3001                         brelse(path[i].p_bh);
3002                         path[i].p_bh = NULL;
3003                         i--;
3004                         ext_debug(inode, "return to level %d\n", i);
3005                 }
3006         }
3007
3008         trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3009                                          path->p_hdr->eh_entries);
3010
3011         /*
3012          * if there's a partial cluster and we have removed the first extent
3013          * in the file, then we also free the partial cluster, if any
3014          */
3015         if (partial.state == tofree && err == 0) {
3016                 int flags = get_default_free_blocks_flags(inode);
3017
3018                 if (ext4_is_pending(inode, partial.lblk))
3019                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3020                 ext4_free_blocks(handle, inode, NULL,
3021                                  EXT4_C2B(sbi, partial.pclu),
3022                                  sbi->s_cluster_ratio, flags);
3023                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3024                         ext4_rereserve_cluster(inode, partial.lblk);
3025                 partial.state = initial;
3026         }
3027
3028         /* TODO: flexible tree reduction should be here */
3029         if (path->p_hdr->eh_entries == 0) {
3030                 /*
3031                  * truncate to zero freed all the tree,
3032                  * so we need to correct eh_depth
3033                  */
3034                 err = ext4_ext_get_access(handle, inode, path);
3035                 if (err == 0) {
3036                         ext_inode_hdr(inode)->eh_depth = 0;
3037                         ext_inode_hdr(inode)->eh_max =
3038                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3039                         err = ext4_ext_dirty(handle, inode, path);
3040                 }
3041         }
3042 out:
3043         ext4_free_ext_path(path);
3044         path = NULL;
3045         if (err == -EAGAIN)
3046                 goto again;
3047         ext4_journal_stop(handle);
3048
3049         return err;
3050 }
3051
3052 /*
3053  * called at mount time
3054  */
3055 void ext4_ext_init(struct super_block *sb)
3056 {
3057         /*
3058          * possible initialization would be here
3059          */
3060
3061         if (ext4_has_feature_extents(sb)) {
3062 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3063                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3064 #ifdef AGGRESSIVE_TEST
3065                        ", aggressive tests"
3066 #endif
3067 #ifdef CHECK_BINSEARCH
3068                        ", check binsearch"
3069 #endif
3070 #ifdef EXTENTS_STATS
3071                        ", stats"
3072 #endif
3073                        "\n");
3074 #endif
3075 #ifdef EXTENTS_STATS
3076                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3077                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3078                 EXT4_SB(sb)->s_ext_max = 0;
3079 #endif
3080         }
3081 }
3082
3083 /*
3084  * called at umount time
3085  */
3086 void ext4_ext_release(struct super_block *sb)
3087 {
3088         if (!ext4_has_feature_extents(sb))
3089                 return;
3090
3091 #ifdef EXTENTS_STATS
3092         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3093                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3094                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3095                         sbi->s_ext_blocks, sbi->s_ext_extents,
3096                         sbi->s_ext_blocks / sbi->s_ext_extents);
3097                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3098                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3099         }
3100 #endif
3101 }
3102
3103 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3104 {
3105         ext4_lblk_t  ee_block;
3106         ext4_fsblk_t ee_pblock;
3107         unsigned int ee_len;
3108
3109         ee_block  = le32_to_cpu(ex->ee_block);
3110         ee_len    = ext4_ext_get_actual_len(ex);
3111         ee_pblock = ext4_ext_pblock(ex);
3112
3113         if (ee_len == 0)
3114                 return 0;
3115
3116         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3117                                      EXTENT_STATUS_WRITTEN);
3118 }
3119
3120 /* FIXME!! we need to try to merge to left or right after zero-out  */
3121 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3122 {
3123         ext4_fsblk_t ee_pblock;
3124         unsigned int ee_len;
3125
3126         ee_len    = ext4_ext_get_actual_len(ex);
3127         ee_pblock = ext4_ext_pblock(ex);
3128         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3129                                   ee_len);
3130 }
3131
3132 /*
3133  * ext4_split_extent_at() splits an extent at given block.
3134  *
3135  * @handle: the journal handle
3136  * @inode: the file inode
3137  * @path: the path to the extent
3138  * @split: the logical block where the extent is splitted.
3139  * @split_flags: indicates if the extent could be zeroout if split fails, and
3140  *               the states(init or unwritten) of new extents.
3141  * @flags: flags used to insert new extent to extent tree.
3142  *
3143  *
3144  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3145  * of which are determined by split_flag.
3146  *
3147  * There are two cases:
3148  *  a> the extent are splitted into two extent.
3149  *  b> split is not needed, and just mark the extent.
3150  *
3151  * return 0 on success.
3152  */
3153 static int ext4_split_extent_at(handle_t *handle,
3154                              struct inode *inode,
3155                              struct ext4_ext_path **ppath,
3156                              ext4_lblk_t split,
3157                              int split_flag,
3158                              int flags)
3159 {
3160         struct ext4_ext_path *path = *ppath;
3161         ext4_fsblk_t newblock;
3162         ext4_lblk_t ee_block;
3163         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3164         struct ext4_extent *ex2 = NULL;
3165         unsigned int ee_len, depth;
3166         int err = 0;
3167
3168         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3169                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3170
3171         ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
3172
3173         ext4_ext_show_leaf(inode, path);
3174
3175         depth = ext_depth(inode);
3176         ex = path[depth].p_ext;
3177         ee_block = le32_to_cpu(ex->ee_block);
3178         ee_len = ext4_ext_get_actual_len(ex);
3179         newblock = split - ee_block + ext4_ext_pblock(ex);
3180
3181         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3182         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3183                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3184                              EXT4_EXT_MARK_UNWRIT1 |
3185                              EXT4_EXT_MARK_UNWRIT2));
3186
3187         err = ext4_ext_get_access(handle, inode, path + depth);
3188         if (err)
3189                 goto out;
3190
3191         if (split == ee_block) {
3192                 /*
3193                  * case b: block @split is the block that the extent begins with
3194                  * then we just change the state of the extent, and splitting
3195                  * is not needed.
3196                  */
3197                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3198                         ext4_ext_mark_unwritten(ex);
3199                 else
3200                         ext4_ext_mark_initialized(ex);
3201
3202                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3203                         ext4_ext_try_to_merge(handle, inode, path, ex);
3204
3205                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3206                 goto out;
3207         }
3208
3209         /* case a */
3210         memcpy(&orig_ex, ex, sizeof(orig_ex));
3211         ex->ee_len = cpu_to_le16(split - ee_block);
3212         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3213                 ext4_ext_mark_unwritten(ex);
3214
3215         /*
3216          * path may lead to new leaf, not to original leaf any more
3217          * after ext4_ext_insert_extent() returns,
3218          */
3219         err = ext4_ext_dirty(handle, inode, path + depth);
3220         if (err)
3221                 goto fix_extent_len;
3222
3223         ex2 = &newex;
3224         ex2->ee_block = cpu_to_le32(split);
3225         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3226         ext4_ext_store_pblock(ex2, newblock);
3227         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3228                 ext4_ext_mark_unwritten(ex2);
3229
3230         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3231         if (err != -ENOSPC && err != -EDQUOT)
3232                 goto out;
3233
3234         if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
3235                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3236                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3237                                 err = ext4_ext_zeroout(inode, ex2);
3238                                 zero_ex.ee_block = ex2->ee_block;
3239                                 zero_ex.ee_len = cpu_to_le16(
3240                                                 ext4_ext_get_actual_len(ex2));
3241                                 ext4_ext_store_pblock(&zero_ex,
3242                                                       ext4_ext_pblock(ex2));
3243                         } else {
3244                                 err = ext4_ext_zeroout(inode, ex);
3245                                 zero_ex.ee_block = ex->ee_block;
3246                                 zero_ex.ee_len = cpu_to_le16(
3247                                                 ext4_ext_get_actual_len(ex));
3248                                 ext4_ext_store_pblock(&zero_ex,
3249                                                       ext4_ext_pblock(ex));
3250                         }
3251                 } else {
3252                         err = ext4_ext_zeroout(inode, &orig_ex);
3253                         zero_ex.ee_block = orig_ex.ee_block;
3254                         zero_ex.ee_len = cpu_to_le16(
3255                                                 ext4_ext_get_actual_len(&orig_ex));
3256                         ext4_ext_store_pblock(&zero_ex,
3257                                               ext4_ext_pblock(&orig_ex));
3258                 }
3259
3260                 if (!err) {
3261                         /* update the extent length and mark as initialized */
3262                         ex->ee_len = cpu_to_le16(ee_len);
3263                         ext4_ext_try_to_merge(handle, inode, path, ex);
3264                         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3265                         if (!err)
3266                                 /* update extent status tree */
3267                                 err = ext4_zeroout_es(inode, &zero_ex);
3268                         /* If we failed at this point, we don't know in which
3269                          * state the extent tree exactly is so don't try to fix
3270                          * length of the original extent as it may do even more
3271                          * damage.
3272                          */
3273                         goto out;
3274                 }
3275         }
3276
3277 fix_extent_len:
3278         ex->ee_len = orig_ex.ee_len;
3279         /*
3280          * Ignore ext4_ext_dirty return value since we are already in error path
3281          * and err is a non-zero error code.
3282          */
3283         ext4_ext_dirty(handle, inode, path + path->p_depth);
3284         return err;
3285 out:
3286         ext4_ext_show_leaf(inode, path);
3287         return err;
3288 }
3289
3290 /*
3291  * ext4_split_extents() splits an extent and mark extent which is covered
3292  * by @map as split_flags indicates
3293  *
3294  * It may result in splitting the extent into multiple extents (up to three)
3295  * There are three possibilities:
3296  *   a> There is no split required
3297  *   b> Splits in two extents: Split is happening at either end of the extent
3298  *   c> Splits in three extents: Somone is splitting in middle of the extent
3299  *
3300  */
3301 static int ext4_split_extent(handle_t *handle,
3302                               struct inode *inode,
3303                               struct ext4_ext_path **ppath,
3304                               struct ext4_map_blocks *map,
3305                               int split_flag,
3306                               int flags)
3307 {
3308         struct ext4_ext_path *path = *ppath;
3309         ext4_lblk_t ee_block;
3310         struct ext4_extent *ex;
3311         unsigned int ee_len, depth;
3312         int err = 0;
3313         int unwritten;
3314         int split_flag1, flags1;
3315         int allocated = map->m_len;
3316
3317         depth = ext_depth(inode);
3318         ex = path[depth].p_ext;
3319         ee_block = le32_to_cpu(ex->ee_block);
3320         ee_len = ext4_ext_get_actual_len(ex);
3321         unwritten = ext4_ext_is_unwritten(ex);
3322
3323         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3324                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3325                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3326                 if (unwritten)
3327                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3328                                        EXT4_EXT_MARK_UNWRIT2;
3329                 if (split_flag & EXT4_EXT_DATA_VALID2)
3330                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3331                 err = ext4_split_extent_at(handle, inode, ppath,
3332                                 map->m_lblk + map->m_len, split_flag1, flags1);
3333                 if (err)
3334                         goto out;
3335         } else {
3336                 allocated = ee_len - (map->m_lblk - ee_block);
3337         }
3338         /*
3339          * Update path is required because previous ext4_split_extent_at() may
3340          * result in split of original leaf or extent zeroout.
3341          */
3342         path = ext4_find_extent(inode, map->m_lblk, ppath, flags);
3343         if (IS_ERR(path))
3344                 return PTR_ERR(path);
3345         depth = ext_depth(inode);
3346         ex = path[depth].p_ext;
3347         if (!ex) {
3348                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3349                                  (unsigned long) map->m_lblk);
3350                 return -EFSCORRUPTED;
3351         }
3352         unwritten = ext4_ext_is_unwritten(ex);
3353
3354         if (map->m_lblk >= ee_block) {
3355                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3356                 if (unwritten) {
3357                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3358                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3359                                                      EXT4_EXT_MARK_UNWRIT2);
3360                 }
3361                 err = ext4_split_extent_at(handle, inode, ppath,
3362                                 map->m_lblk, split_flag1, flags);
3363                 if (err)
3364                         goto out;
3365         }
3366
3367         ext4_ext_show_leaf(inode, path);
3368 out:
3369         return err ? err : allocated;
3370 }
3371
3372 /*
3373  * This function is called by ext4_ext_map_blocks() if someone tries to write
3374  * to an unwritten extent. It may result in splitting the unwritten
3375  * extent into multiple extents (up to three - one initialized and two
3376  * unwritten).
3377  * There are three possibilities:
3378  *   a> There is no split required: Entire extent should be initialized
3379  *   b> Splits in two extents: Write is happening at either end of the extent
3380  *   c> Splits in three extents: Somone is writing in middle of the extent
3381  *
3382  * Pre-conditions:
3383  *  - The extent pointed to by 'path' is unwritten.
3384  *  - The extent pointed to by 'path' contains a superset
3385  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3386  *
3387  * Post-conditions on success:
3388  *  - the returned value is the number of blocks beyond map->l_lblk
3389  *    that are allocated and initialized.
3390  *    It is guaranteed to be >= map->m_len.
3391  */
3392 static int ext4_ext_convert_to_initialized(handle_t *handle,
3393                                            struct inode *inode,
3394                                            struct ext4_map_blocks *map,
3395                                            struct ext4_ext_path **ppath,
3396                                            int flags)
3397 {
3398         struct ext4_ext_path *path = *ppath;
3399         struct ext4_sb_info *sbi;
3400         struct ext4_extent_header *eh;
3401         struct ext4_map_blocks split_map;
3402         struct ext4_extent zero_ex1, zero_ex2;
3403         struct ext4_extent *ex, *abut_ex;
3404         ext4_lblk_t ee_block, eof_block;
3405         unsigned int ee_len, depth, map_len = map->m_len;
3406         int allocated = 0, max_zeroout = 0;
3407         int err = 0;
3408         int split_flag = EXT4_EXT_DATA_VALID2;
3409
3410         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3411                   (unsigned long long)map->m_lblk, map_len);
3412
3413         sbi = EXT4_SB(inode->i_sb);
3414         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3415                         >> inode->i_sb->s_blocksize_bits;
3416         if (eof_block < map->m_lblk + map_len)
3417                 eof_block = map->m_lblk + map_len;
3418
3419         depth = ext_depth(inode);
3420         eh = path[depth].p_hdr;
3421         ex = path[depth].p_ext;
3422         ee_block = le32_to_cpu(ex->ee_block);
3423         ee_len = ext4_ext_get_actual_len(ex);
3424         zero_ex1.ee_len = 0;
3425         zero_ex2.ee_len = 0;
3426
3427         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3428
3429         /* Pre-conditions */
3430         BUG_ON(!ext4_ext_is_unwritten(ex));
3431         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3432
3433         /*
3434          * Attempt to transfer newly initialized blocks from the currently
3435          * unwritten extent to its neighbor. This is much cheaper
3436          * than an insertion followed by a merge as those involve costly
3437          * memmove() calls. Transferring to the left is the common case in
3438          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3439          * followed by append writes.
3440          *
3441          * Limitations of the current logic:
3442          *  - L1: we do not deal with writes covering the whole extent.
3443          *    This would require removing the extent if the transfer
3444          *    is possible.
3445          *  - L2: we only attempt to merge with an extent stored in the
3446          *    same extent tree node.
3447          */
3448         if ((map->m_lblk == ee_block) &&
3449                 /* See if we can merge left */
3450                 (map_len < ee_len) &&           /*L1*/
3451                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3452                 ext4_lblk_t prev_lblk;
3453                 ext4_fsblk_t prev_pblk, ee_pblk;
3454                 unsigned int prev_len;
3455
3456                 abut_ex = ex - 1;
3457                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3458                 prev_len = ext4_ext_get_actual_len(abut_ex);
3459                 prev_pblk = ext4_ext_pblock(abut_ex);
3460                 ee_pblk = ext4_ext_pblock(ex);
3461
3462                 /*
3463                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3464                  * upon those conditions:
3465                  * - C1: abut_ex is initialized,
3466                  * - C2: abut_ex is logically abutting ex,
3467                  * - C3: abut_ex is physically abutting ex,
3468                  * - C4: abut_ex can receive the additional blocks without
3469                  *   overflowing the (initialized) length limit.
3470                  */
3471                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3472                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3473                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3474                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3475                         err = ext4_ext_get_access(handle, inode, path + depth);
3476                         if (err)
3477                                 goto out;
3478
3479                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3480                                 map, ex, abut_ex);
3481
3482                         /* Shift the start of ex by 'map_len' blocks */
3483                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3484                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3485                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3486                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3487
3488                         /* Extend abut_ex by 'map_len' blocks */
3489                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3490
3491                         /* Result: number of initialized blocks past m_lblk */
3492                         allocated = map_len;
3493                 }
3494         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3495                    (map_len < ee_len) &&        /*L1*/
3496                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3497                 /* See if we can merge right */
3498                 ext4_lblk_t next_lblk;
3499                 ext4_fsblk_t next_pblk, ee_pblk;
3500                 unsigned int next_len;
3501
3502                 abut_ex = ex + 1;
3503                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3504                 next_len = ext4_ext_get_actual_len(abut_ex);
3505                 next_pblk = ext4_ext_pblock(abut_ex);
3506                 ee_pblk = ext4_ext_pblock(ex);
3507
3508                 /*
3509                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3510                  * upon those conditions:
3511                  * - C1: abut_ex is initialized,
3512                  * - C2: abut_ex is logically abutting ex,
3513                  * - C3: abut_ex is physically abutting ex,
3514                  * - C4: abut_ex can receive the additional blocks without
3515                  *   overflowing the (initialized) length limit.
3516                  */
3517                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3518                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3519                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3520                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3521                         err = ext4_ext_get_access(handle, inode, path + depth);
3522                         if (err)
3523                                 goto out;
3524
3525                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3526                                 map, ex, abut_ex);
3527
3528                         /* Shift the start of abut_ex by 'map_len' blocks */
3529                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3530                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3531                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3532                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3533
3534                         /* Extend abut_ex by 'map_len' blocks */
3535                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3536
3537                         /* Result: number of initialized blocks past m_lblk */
3538                         allocated = map_len;
3539                 }
3540         }
3541         if (allocated) {
3542                 /* Mark the block containing both extents as dirty */
3543                 err = ext4_ext_dirty(handle, inode, path + depth);
3544
3545                 /* Update path to point to the right extent */
3546                 path[depth].p_ext = abut_ex;
3547                 goto out;
3548         } else
3549                 allocated = ee_len - (map->m_lblk - ee_block);
3550
3551         WARN_ON(map->m_lblk < ee_block);
3552         /*
3553          * It is safe to convert extent to initialized via explicit
3554          * zeroout only if extent is fully inside i_size or new_size.
3555          */
3556         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3557
3558         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3559                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3560                         (inode->i_sb->s_blocksize_bits - 10);
3561
3562         /*
3563          * five cases:
3564          * 1. split the extent into three extents.
3565          * 2. split the extent into two extents, zeroout the head of the first
3566          *    extent.
3567          * 3. split the extent into two extents, zeroout the tail of the second
3568          *    extent.
3569          * 4. split the extent into two extents with out zeroout.
3570          * 5. no splitting needed, just possibly zeroout the head and / or the
3571          *    tail of the extent.
3572          */
3573         split_map.m_lblk = map->m_lblk;
3574         split_map.m_len = map->m_len;
3575
3576         if (max_zeroout && (allocated > split_map.m_len)) {
3577                 if (allocated <= max_zeroout) {
3578                         /* case 3 or 5 */
3579                         zero_ex1.ee_block =
3580                                  cpu_to_le32(split_map.m_lblk +
3581                                              split_map.m_len);
3582                         zero_ex1.ee_len =
3583                                 cpu_to_le16(allocated - split_map.m_len);
3584                         ext4_ext_store_pblock(&zero_ex1,
3585                                 ext4_ext_pblock(ex) + split_map.m_lblk +
3586                                 split_map.m_len - ee_block);
3587                         err = ext4_ext_zeroout(inode, &zero_ex1);
3588                         if (err)
3589                                 goto fallback;
3590                         split_map.m_len = allocated;
3591                 }
3592                 if (split_map.m_lblk - ee_block + split_map.m_len <
3593                                                                 max_zeroout) {
3594                         /* case 2 or 5 */
3595                         if (split_map.m_lblk != ee_block) {
3596                                 zero_ex2.ee_block = ex->ee_block;
3597                                 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3598                                                         ee_block);
3599                                 ext4_ext_store_pblock(&zero_ex2,
3600                                                       ext4_ext_pblock(ex));
3601                                 err = ext4_ext_zeroout(inode, &zero_ex2);
3602                                 if (err)
3603                                         goto fallback;
3604                         }
3605
3606                         split_map.m_len += split_map.m_lblk - ee_block;
3607                         split_map.m_lblk = ee_block;
3608                         allocated = map->m_len;
3609                 }
3610         }
3611
3612 fallback:
3613         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3614                                 flags);
3615         if (err > 0)
3616                 err = 0;
3617 out:
3618         /* If we have gotten a failure, don't zero out status tree */
3619         if (!err) {
3620                 err = ext4_zeroout_es(inode, &zero_ex1);
3621                 if (!err)
3622                         err = ext4_zeroout_es(inode, &zero_ex2);
3623         }
3624         return err ? err : allocated;
3625 }
3626
3627 /*
3628  * This function is called by ext4_ext_map_blocks() from
3629  * ext4_get_blocks_dio_write() when DIO to write
3630  * to an unwritten extent.
3631  *
3632  * Writing to an unwritten extent may result in splitting the unwritten
3633  * extent into multiple initialized/unwritten extents (up to three)
3634  * There are three possibilities:
3635  *   a> There is no split required: Entire extent should be unwritten
3636  *   b> Splits in two extents: Write is happening at either end of the extent
3637  *   c> Splits in three extents: Somone is writing in middle of the extent
3638  *
3639  * This works the same way in the case of initialized -> unwritten conversion.
3640  *
3641  * One of more index blocks maybe needed if the extent tree grow after
3642  * the unwritten extent split. To prevent ENOSPC occur at the IO
3643  * complete, we need to split the unwritten extent before DIO submit
3644  * the IO. The unwritten extent called at this time will be split
3645  * into three unwritten extent(at most). After IO complete, the part
3646  * being filled will be convert to initialized by the end_io callback function
3647  * via ext4_convert_unwritten_extents().
3648  *
3649  * Returns the size of unwritten extent to be written on success.
3650  */
3651 static int ext4_split_convert_extents(handle_t *handle,
3652                                         struct inode *inode,
3653                                         struct ext4_map_blocks *map,
3654                                         struct ext4_ext_path **ppath,
3655                                         int flags)
3656 {
3657         struct ext4_ext_path *path = *ppath;
3658         ext4_lblk_t eof_block;
3659         ext4_lblk_t ee_block;
3660         struct ext4_extent *ex;
3661         unsigned int ee_len;
3662         int split_flag = 0, depth;
3663
3664         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3665                   (unsigned long long)map->m_lblk, map->m_len);
3666
3667         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3668                         >> inode->i_sb->s_blocksize_bits;
3669         if (eof_block < map->m_lblk + map->m_len)
3670                 eof_block = map->m_lblk + map->m_len;
3671         /*
3672          * It is safe to convert extent to initialized via explicit
3673          * zeroout only if extent is fully inside i_size or new_size.
3674          */
3675         depth = ext_depth(inode);
3676         ex = path[depth].p_ext;
3677         ee_block = le32_to_cpu(ex->ee_block);
3678         ee_len = ext4_ext_get_actual_len(ex);
3679
3680         /* Convert to unwritten */
3681         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3682                 split_flag |= EXT4_EXT_DATA_VALID1;
3683         /* Convert to initialized */
3684         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3685                 split_flag |= ee_block + ee_len <= eof_block ?
3686                               EXT4_EXT_MAY_ZEROOUT : 0;
3687                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3688         }
3689         flags |= EXT4_GET_BLOCKS_PRE_IO;
3690         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3691 }
3692
3693 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3694                                                 struct inode *inode,
3695                                                 struct ext4_map_blocks *map,
3696                                                 struct ext4_ext_path **ppath)
3697 {
3698         struct ext4_ext_path *path = *ppath;
3699         struct ext4_extent *ex;
3700         ext4_lblk_t ee_block;
3701         unsigned int ee_len;
3702         int depth;
3703         int err = 0;
3704
3705         depth = ext_depth(inode);
3706         ex = path[depth].p_ext;
3707         ee_block = le32_to_cpu(ex->ee_block);
3708         ee_len = ext4_ext_get_actual_len(ex);
3709
3710         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3711                   (unsigned long long)ee_block, ee_len);
3712
3713         /* If extent is larger than requested it is a clear sign that we still
3714          * have some extent state machine issues left. So extent_split is still
3715          * required.
3716          * TODO: Once all related issues will be fixed this situation should be
3717          * illegal.
3718          */
3719         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3720 #ifdef CONFIG_EXT4_DEBUG
3721                 ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3722                              " len %u; IO logical block %llu, len %u",
3723                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3724                              (unsigned long long)map->m_lblk, map->m_len);
3725 #endif
3726                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3727                                                  EXT4_GET_BLOCKS_CONVERT);
3728                 if (err < 0)
3729                         return err;
3730                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3731                 if (IS_ERR(path))
3732                         return PTR_ERR(path);
3733                 depth = ext_depth(inode);
3734                 ex = path[depth].p_ext;
3735         }
3736
3737         err = ext4_ext_get_access(handle, inode, path + depth);
3738         if (err)
3739                 goto out;
3740         /* first mark the extent as initialized */
3741         ext4_ext_mark_initialized(ex);
3742
3743         /* note: ext4_ext_correct_indexes() isn't needed here because
3744          * borders are not changed
3745          */
3746         ext4_ext_try_to_merge(handle, inode, path, ex);
3747
3748         /* Mark modified extent as dirty */
3749         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3750 out:
3751         ext4_ext_show_leaf(inode, path);
3752         return err;
3753 }
3754
3755 static int
3756 convert_initialized_extent(handle_t *handle, struct inode *inode,
3757                            struct ext4_map_blocks *map,
3758                            struct ext4_ext_path **ppath,
3759                            unsigned int *allocated)
3760 {
3761         struct ext4_ext_path *path = *ppath;
3762         struct ext4_extent *ex;
3763         ext4_lblk_t ee_block;
3764         unsigned int ee_len;
3765         int depth;
3766         int err = 0;
3767
3768         /*
3769          * Make sure that the extent is no bigger than we support with
3770          * unwritten extent
3771          */
3772         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3773                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3774
3775         depth = ext_depth(inode);
3776         ex = path[depth].p_ext;
3777         ee_block = le32_to_cpu(ex->ee_block);
3778         ee_len = ext4_ext_get_actual_len(ex);
3779
3780         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3781                   (unsigned long long)ee_block, ee_len);
3782
3783         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3784                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3785                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3786                 if (err < 0)
3787                         return err;
3788                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3789                 if (IS_ERR(path))
3790                         return PTR_ERR(path);
3791                 depth = ext_depth(inode);
3792                 ex = path[depth].p_ext;
3793                 if (!ex) {
3794                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3795                                          (unsigned long) map->m_lblk);
3796                         return -EFSCORRUPTED;
3797                 }
3798         }
3799
3800         err = ext4_ext_get_access(handle, inode, path + depth);
3801         if (err)
3802                 return err;
3803         /* first mark the extent as unwritten */
3804         ext4_ext_mark_unwritten(ex);
3805
3806         /* note: ext4_ext_correct_indexes() isn't needed here because
3807          * borders are not changed
3808          */
3809         ext4_ext_try_to_merge(handle, inode, path, ex);
3810
3811         /* Mark modified extent as dirty */
3812         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3813         if (err)
3814                 return err;
3815         ext4_ext_show_leaf(inode, path);
3816
3817         ext4_update_inode_fsync_trans(handle, inode, 1);
3818
3819         map->m_flags |= EXT4_MAP_UNWRITTEN;
3820         if (*allocated > map->m_len)
3821                 *allocated = map->m_len;
3822         map->m_len = *allocated;
3823         return 0;
3824 }
3825
3826 static int
3827 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3828                         struct ext4_map_blocks *map,
3829                         struct ext4_ext_path **ppath, int flags,
3830                         unsigned int allocated, ext4_fsblk_t newblock)
3831 {
3832         struct ext4_ext_path __maybe_unused *path = *ppath;
3833         int ret = 0;
3834         int err = 0;
3835
3836         ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
3837                   (unsigned long long)map->m_lblk, map->m_len, flags,
3838                   allocated);
3839         ext4_ext_show_leaf(inode, path);
3840
3841         /*
3842          * When writing into unwritten space, we should not fail to
3843          * allocate metadata blocks for the new extent block if needed.
3844          */
3845         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3846
3847         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
3848                                                     allocated, newblock);
3849
3850         /* get_block() before submitting IO, split the extent */
3851         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
3852                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
3853                                          flags | EXT4_GET_BLOCKS_CONVERT);
3854                 if (ret < 0) {
3855                         err = ret;
3856                         goto out2;
3857                 }
3858                 /*
3859                  * shouldn't get a 0 return when splitting an extent unless
3860                  * m_len is 0 (bug) or extent has been corrupted
3861                  */
3862                 if (unlikely(ret == 0)) {
3863                         EXT4_ERROR_INODE(inode,
3864                                          "unexpected ret == 0, m_len = %u",
3865                                          map->m_len);
3866                         err = -EFSCORRUPTED;
3867                         goto out2;
3868                 }
3869                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3870                 goto out;
3871         }
3872         /* IO end_io complete, convert the filled extent to written */
3873         if (flags & EXT4_GET_BLOCKS_CONVERT) {
3874                 err = ext4_convert_unwritten_extents_endio(handle, inode, map,
3875                                                            ppath);
3876                 if (err < 0)
3877                         goto out2;
3878                 ext4_update_inode_fsync_trans(handle, inode, 1);
3879                 goto map_out;
3880         }
3881         /* buffered IO cases */
3882         /*
3883          * repeat fallocate creation request
3884          * we already have an unwritten extent
3885          */
3886         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
3887                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3888                 goto map_out;
3889         }
3890
3891         /* buffered READ or buffered write_begin() lookup */
3892         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3893                 /*
3894                  * We have blocks reserved already.  We
3895                  * return allocated blocks so that delalloc
3896                  * won't do block reservation for us.  But
3897                  * the buffer head will be unmapped so that
3898                  * a read from the block returns 0s.
3899                  */
3900                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3901                 goto out1;
3902         }
3903
3904         /*
3905          * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
3906          * For buffered writes, at writepage time, etc.  Convert a
3907          * discovered unwritten extent to written.
3908          */
3909         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
3910         if (ret < 0) {
3911                 err = ret;
3912                 goto out2;
3913         }
3914         ext4_update_inode_fsync_trans(handle, inode, 1);
3915         /*
3916          * shouldn't get a 0 return when converting an unwritten extent
3917          * unless m_len is 0 (bug) or extent has been corrupted
3918          */
3919         if (unlikely(ret == 0)) {
3920                 EXT4_ERROR_INODE(inode, "unexpected ret == 0, m_len = %u",
3921                                  map->m_len);
3922                 err = -EFSCORRUPTED;
3923                 goto out2;
3924         }
3925
3926 out:
3927         allocated = ret;
3928         map->m_flags |= EXT4_MAP_NEW;
3929 map_out:
3930         map->m_flags |= EXT4_MAP_MAPPED;
3931 out1:
3932         map->m_pblk = newblock;
3933         if (allocated > map->m_len)
3934                 allocated = map->m_len;
3935         map->m_len = allocated;
3936         ext4_ext_show_leaf(inode, path);
3937 out2:
3938         return err ? err : allocated;
3939 }
3940
3941 /*
3942  * get_implied_cluster_alloc - check to see if the requested
3943  * allocation (in the map structure) overlaps with a cluster already
3944  * allocated in an extent.
3945  *      @sb     The filesystem superblock structure
3946  *      @map    The requested lblk->pblk mapping
3947  *      @ex     The extent structure which might contain an implied
3948  *                      cluster allocation
3949  *
3950  * This function is called by ext4_ext_map_blocks() after we failed to
3951  * find blocks that were already in the inode's extent tree.  Hence,
3952  * we know that the beginning of the requested region cannot overlap
3953  * the extent from the inode's extent tree.  There are three cases we
3954  * want to catch.  The first is this case:
3955  *
3956  *               |--- cluster # N--|
3957  *    |--- extent ---|  |---- requested region ---|
3958  *                      |==========|
3959  *
3960  * The second case that we need to test for is this one:
3961  *
3962  *   |--------- cluster # N ----------------|
3963  *         |--- requested region --|   |------- extent ----|
3964  *         |=======================|
3965  *
3966  * The third case is when the requested region lies between two extents
3967  * within the same cluster:
3968  *          |------------- cluster # N-------------|
3969  * |----- ex -----|                  |---- ex_right ----|
3970  *                  |------ requested region ------|
3971  *                  |================|
3972  *
3973  * In each of the above cases, we need to set the map->m_pblk and
3974  * map->m_len so it corresponds to the return the extent labelled as
3975  * "|====|" from cluster #N, since it is already in use for data in
3976  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
3977  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
3978  * as a new "allocated" block region.  Otherwise, we will return 0 and
3979  * ext4_ext_map_blocks() will then allocate one or more new clusters
3980  * by calling ext4_mb_new_blocks().
3981  */
3982 static int get_implied_cluster_alloc(struct super_block *sb,
3983                                      struct ext4_map_blocks *map,
3984                                      struct ext4_extent *ex,
3985                                      struct ext4_ext_path *path)
3986 {
3987         struct ext4_sb_info *sbi = EXT4_SB(sb);
3988         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
3989         ext4_lblk_t ex_cluster_start, ex_cluster_end;
3990         ext4_lblk_t rr_cluster_start;
3991         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3992         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3993         unsigned short ee_len = ext4_ext_get_actual_len(ex);
3994
3995         /* The extent passed in that we are trying to match */
3996         ex_cluster_start = EXT4_B2C(sbi, ee_block);
3997         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
3998
3999         /* The requested region passed into ext4_map_blocks() */
4000         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4001
4002         if ((rr_cluster_start == ex_cluster_end) ||
4003             (rr_cluster_start == ex_cluster_start)) {
4004                 if (rr_cluster_start == ex_cluster_end)
4005                         ee_start += ee_len - 1;
4006                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4007                 map->m_len = min(map->m_len,
4008                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4009                 /*
4010                  * Check for and handle this case:
4011                  *
4012                  *   |--------- cluster # N-------------|
4013                  *                     |------- extent ----|
4014                  *         |--- requested region ---|
4015                  *         |===========|
4016                  */
4017
4018                 if (map->m_lblk < ee_block)
4019                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4020
4021                 /*
4022                  * Check for the case where there is already another allocated
4023                  * block to the right of 'ex' but before the end of the cluster.
4024                  *
4025                  *          |------------- cluster # N-------------|
4026                  * |----- ex -----|                  |---- ex_right ----|
4027                  *                  |------ requested region ------|
4028                  *                  |================|
4029                  */
4030                 if (map->m_lblk > ee_block) {
4031                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4032                         map->m_len = min(map->m_len, next - map->m_lblk);
4033                 }
4034
4035                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4036                 return 1;
4037         }
4038
4039         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4040         return 0;
4041 }
4042
4043 /*
4044  * Determine hole length around the given logical block, first try to
4045  * locate and expand the hole from the given @path, and then adjust it
4046  * if it's partially or completely converted to delayed extents, insert
4047  * it into the extent cache tree if it's indeed a hole, finally return
4048  * the length of the determined extent.
4049  */
4050 static ext4_lblk_t ext4_ext_determine_insert_hole(struct inode *inode,
4051                                                   struct ext4_ext_path *path,
4052                                                   ext4_lblk_t lblk)
4053 {
4054         ext4_lblk_t hole_start, len;
4055         struct extent_status es;
4056
4057         hole_start = lblk;
4058         len = ext4_ext_find_hole(inode, path, &hole_start);
4059 again:
4060         ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
4061                                   hole_start + len - 1, &es);
4062         if (!es.es_len)
4063                 goto insert_hole;
4064
4065         /*
4066          * There's a delalloc extent in the hole, handle it if the delalloc
4067          * extent is in front of, behind and straddle the queried range.
4068          */
4069         if (lblk >= es.es_lblk + es.es_len) {
4070                 /*
4071                  * The delalloc extent is in front of the queried range,
4072                  * find again from the queried start block.
4073                  */
4074                 len -= lblk - hole_start;
4075                 hole_start = lblk;
4076                 goto again;
4077         } else if (in_range(lblk, es.es_lblk, es.es_len)) {
4078                 /*
4079                  * The delalloc extent containing lblk, it must have been
4080                  * added after ext4_map_blocks() checked the extent status
4081                  * tree, adjust the length to the delalloc extent's after
4082                  * lblk.
4083                  */
4084                 len = es.es_lblk + es.es_len - lblk;
4085                 return len;
4086         } else {
4087                 /*
4088                  * The delalloc extent is partially or completely behind
4089                  * the queried range, update hole length until the
4090                  * beginning of the delalloc extent.
4091                  */
4092                 len = min(es.es_lblk - hole_start, len);
4093         }
4094
4095 insert_hole:
4096         /* Put just found gap into cache to speed up subsequent requests */
4097         ext_debug(inode, " -> %u:%u\n", hole_start, len);
4098         ext4_es_insert_extent(inode, hole_start, len, ~0, EXTENT_STATUS_HOLE);
4099
4100         /* Update hole_len to reflect hole size after lblk */
4101         if (hole_start != lblk)
4102                 len -= lblk - hole_start;
4103
4104         return len;
4105 }
4106
4107 /*
4108  * Block allocation/map/preallocation routine for extents based files
4109  *
4110  *
4111  * Need to be called with
4112  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4113  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4114  *
4115  * return > 0, number of blocks already mapped/allocated
4116  *          if create == 0 and these are pre-allocated blocks
4117  *              buffer head is unmapped
4118  *          otherwise blocks are mapped
4119  *
4120  * return = 0, if plain look up failed (blocks have not been allocated)
4121  *          buffer head is unmapped
4122  *
4123  * return < 0, error case.
4124  */
4125 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4126                         struct ext4_map_blocks *map, int flags)
4127 {
4128         struct ext4_ext_path *path = NULL;
4129         struct ext4_extent newex, *ex, ex2;
4130         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4131         ext4_fsblk_t newblock = 0, pblk;
4132         int err = 0, depth, ret;
4133         unsigned int allocated = 0, offset = 0;
4134         unsigned int allocated_clusters = 0;
4135         struct ext4_allocation_request ar;
4136         ext4_lblk_t cluster_offset;
4137
4138         ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
4139         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4140
4141         /* find extent for this block */
4142         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4143         if (IS_ERR(path)) {
4144                 err = PTR_ERR(path);
4145                 path = NULL;
4146                 goto out;
4147         }
4148
4149         depth = ext_depth(inode);
4150
4151         /*
4152          * consistent leaf must not be empty;
4153          * this situation is possible, though, _during_ tree modification;
4154          * this is why assert can't be put in ext4_find_extent()
4155          */
4156         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4157                 EXT4_ERROR_INODE(inode, "bad extent address "
4158                                  "lblock: %lu, depth: %d pblock %lld",
4159                                  (unsigned long) map->m_lblk, depth,
4160                                  path[depth].p_block);
4161                 err = -EFSCORRUPTED;
4162                 goto out;
4163         }
4164
4165         ex = path[depth].p_ext;
4166         if (ex) {
4167                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4168                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4169                 unsigned short ee_len;
4170
4171
4172                 /*
4173                  * unwritten extents are treated as holes, except that
4174                  * we split out initialized portions during a write.
4175                  */
4176                 ee_len = ext4_ext_get_actual_len(ex);
4177
4178                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4179
4180                 /* if found extent covers block, simply return it */
4181                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4182                         newblock = map->m_lblk - ee_block + ee_start;
4183                         /* number of remaining blocks in the extent */
4184                         allocated = ee_len - (map->m_lblk - ee_block);
4185                         ext_debug(inode, "%u fit into %u:%d -> %llu\n",
4186                                   map->m_lblk, ee_block, ee_len, newblock);
4187
4188                         /*
4189                          * If the extent is initialized check whether the
4190                          * caller wants to convert it to unwritten.
4191                          */
4192                         if ((!ext4_ext_is_unwritten(ex)) &&
4193                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4194                                 err = convert_initialized_extent(handle,
4195                                         inode, map, &path, &allocated);
4196                                 goto out;
4197                         } else if (!ext4_ext_is_unwritten(ex)) {
4198                                 map->m_flags |= EXT4_MAP_MAPPED;
4199                                 map->m_pblk = newblock;
4200                                 if (allocated > map->m_len)
4201                                         allocated = map->m_len;
4202                                 map->m_len = allocated;
4203                                 ext4_ext_show_leaf(inode, path);
4204                                 goto out;
4205                         }
4206
4207                         ret = ext4_ext_handle_unwritten_extents(
4208                                 handle, inode, map, &path, flags,
4209                                 allocated, newblock);
4210                         if (ret < 0)
4211                                 err = ret;
4212                         else
4213                                 allocated = ret;
4214                         goto out;
4215                 }
4216         }
4217
4218         /*
4219          * requested block isn't allocated yet;
4220          * we couldn't try to create block if create flag is zero
4221          */
4222         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4223                 ext4_lblk_t len;
4224
4225                 len = ext4_ext_determine_insert_hole(inode, path, map->m_lblk);
4226
4227                 map->m_pblk = 0;
4228                 map->m_len = min_t(unsigned int, map->m_len, len);
4229                 goto out;
4230         }
4231
4232         /*
4233          * Okay, we need to do block allocation.
4234          */
4235         newex.ee_block = cpu_to_le32(map->m_lblk);
4236         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4237
4238         /*
4239          * If we are doing bigalloc, check to see if the extent returned
4240          * by ext4_find_extent() implies a cluster we can use.
4241          */
4242         if (cluster_offset && ex &&
4243             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4244                 ar.len = allocated = map->m_len;
4245                 newblock = map->m_pblk;
4246                 goto got_allocated_blocks;
4247         }
4248
4249         /* find neighbour allocated blocks */
4250         ar.lleft = map->m_lblk;
4251         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4252         if (err)
4253                 goto out;
4254         ar.lright = map->m_lblk;
4255         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4256         if (err < 0)
4257                 goto out;
4258
4259         /* Check if the extent after searching to the right implies a
4260          * cluster we can use. */
4261         if ((sbi->s_cluster_ratio > 1) && err &&
4262             get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
4263                 ar.len = allocated = map->m_len;
4264                 newblock = map->m_pblk;
4265                 goto got_allocated_blocks;
4266         }
4267
4268         /*
4269          * See if request is beyond maximum number of blocks we can have in
4270          * a single extent. For an initialized extent this limit is
4271          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4272          * EXT_UNWRITTEN_MAX_LEN.
4273          */
4274         if (map->m_len > EXT_INIT_MAX_LEN &&
4275             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4276                 map->m_len = EXT_INIT_MAX_LEN;
4277         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4278                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4279                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4280
4281         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4282         newex.ee_len = cpu_to_le16(map->m_len);
4283         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4284         if (err)
4285                 allocated = ext4_ext_get_actual_len(&newex);
4286         else
4287                 allocated = map->m_len;
4288
4289         /* allocate new block */
4290         ar.inode = inode;
4291         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4292         ar.logical = map->m_lblk;
4293         /*
4294          * We calculate the offset from the beginning of the cluster
4295          * for the logical block number, since when we allocate a
4296          * physical cluster, the physical block should start at the
4297          * same offset from the beginning of the cluster.  This is
4298          * needed so that future calls to get_implied_cluster_alloc()
4299          * work correctly.
4300          */
4301         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4302         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4303         ar.goal -= offset;
4304         ar.logical -= offset;
4305         if (S_ISREG(inode->i_mode))
4306                 ar.flags = EXT4_MB_HINT_DATA;
4307         else
4308                 /* disable in-core preallocation for non-regular files */
4309                 ar.flags = 0;
4310         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4311                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4312         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4313                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4314         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4315                 ar.flags |= EXT4_MB_USE_RESERVED;
4316         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4317         if (!newblock)
4318                 goto out;
4319         allocated_clusters = ar.len;
4320         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4321         ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
4322                   ar.goal, newblock, ar.len, allocated);
4323         if (ar.len > allocated)
4324                 ar.len = allocated;
4325
4326 got_allocated_blocks:
4327         /* try to insert new extent into found leaf and return */
4328         pblk = newblock + offset;
4329         ext4_ext_store_pblock(&newex, pblk);
4330         newex.ee_len = cpu_to_le16(ar.len);
4331         /* Mark unwritten */
4332         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4333                 ext4_ext_mark_unwritten(&newex);
4334                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4335         }
4336
4337         err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags);
4338         if (err) {
4339                 if (allocated_clusters) {
4340                         int fb_flags = 0;
4341
4342                         /*
4343                          * free data blocks we just allocated.
4344                          * not a good idea to call discard here directly,
4345                          * but otherwise we'd need to call it every free().
4346                          */
4347                         ext4_discard_preallocations(inode, 0);
4348                         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4349                                 fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
4350                         ext4_free_blocks(handle, inode, NULL, newblock,
4351                                          EXT4_C2B(sbi, allocated_clusters),
4352                                          fb_flags);
4353                 }
4354                 goto out;
4355         }
4356
4357         /*
4358          * Reduce the reserved cluster count to reflect successful deferred
4359          * allocation of delayed allocated clusters or direct allocation of
4360          * clusters discovered to be delayed allocated.  Once allocated, a
4361          * cluster is not included in the reserved count.
4362          */
4363         if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
4364                 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4365                         /*
4366                          * When allocating delayed allocated clusters, simply
4367                          * reduce the reserved cluster count and claim quota
4368                          */
4369                         ext4_da_update_reserve_space(inode, allocated_clusters,
4370                                                         1);
4371                 } else {
4372                         ext4_lblk_t lblk, len;
4373                         unsigned int n;
4374
4375                         /*
4376                          * When allocating non-delayed allocated clusters
4377                          * (from fallocate, filemap, DIO, or clusters
4378                          * allocated when delalloc has been disabled by
4379                          * ext4_nonda_switch), reduce the reserved cluster
4380                          * count by the number of allocated clusters that
4381                          * have previously been delayed allocated.  Quota
4382                          * has been claimed by ext4_mb_new_blocks() above,
4383                          * so release the quota reservations made for any
4384                          * previously delayed allocated clusters.
4385                          */
4386                         lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4387                         len = allocated_clusters << sbi->s_cluster_bits;
4388                         n = ext4_es_delayed_clu(inode, lblk, len);
4389                         if (n > 0)
4390                                 ext4_da_update_reserve_space(inode, (int) n, 0);
4391                 }
4392         }
4393
4394         /*
4395          * Cache the extent and update transaction to commit on fdatasync only
4396          * when it is _not_ an unwritten extent.
4397          */
4398         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4399                 ext4_update_inode_fsync_trans(handle, inode, 1);
4400         else
4401                 ext4_update_inode_fsync_trans(handle, inode, 0);
4402
4403         map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
4404         map->m_pblk = pblk;
4405         map->m_len = ar.len;
4406         allocated = map->m_len;
4407         ext4_ext_show_leaf(inode, path);
4408 out:
4409         ext4_free_ext_path(path);
4410
4411         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4412                                        err ? err : allocated);
4413         return err ? err : allocated;
4414 }
4415
4416 int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4417 {
4418         struct super_block *sb = inode->i_sb;
4419         ext4_lblk_t last_block;
4420         int err = 0;
4421
4422         /*
4423          * TODO: optimization is possible here.
4424          * Probably we need not scan at all,
4425          * because page truncation is enough.
4426          */
4427
4428         /* we have to know where to truncate from in crash case */
4429         EXT4_I(inode)->i_disksize = inode->i_size;
4430         err = ext4_mark_inode_dirty(handle, inode);
4431         if (err)
4432                 return err;
4433
4434         last_block = (inode->i_size + sb->s_blocksize - 1)
4435                         >> EXT4_BLOCK_SIZE_BITS(sb);
4436 retry:
4437         err = ext4_es_remove_extent(inode, last_block,
4438                                     EXT_MAX_BLOCKS - last_block);
4439         if (err == -ENOMEM) {
4440                 memalloc_retry_wait(GFP_ATOMIC);
4441                 goto retry;
4442         }
4443         if (err)
4444                 return err;
4445 retry_remove_space:
4446         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4447         if (err == -ENOMEM) {
4448                 memalloc_retry_wait(GFP_ATOMIC);
4449                 goto retry_remove_space;
4450         }
4451         return err;
4452 }
4453
4454 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4455                                   ext4_lblk_t len, loff_t new_size,
4456                                   int flags)
4457 {
4458         struct inode *inode = file_inode(file);
4459         handle_t *handle;
4460         int ret = 0, ret2 = 0, ret3 = 0;
4461         int retries = 0;
4462         int depth = 0;
4463         struct ext4_map_blocks map;
4464         unsigned int credits;
4465         loff_t epos;
4466
4467         BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4468         map.m_lblk = offset;
4469         map.m_len = len;
4470         /*
4471          * Don't normalize the request if it can fit in one extent so
4472          * that it doesn't get unnecessarily split into multiple
4473          * extents.
4474          */
4475         if (len <= EXT_UNWRITTEN_MAX_LEN)
4476                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4477
4478         /*
4479          * credits to insert 1 extent into extent tree
4480          */
4481         credits = ext4_chunk_trans_blocks(inode, len);
4482         depth = ext_depth(inode);
4483
4484 retry:
4485         while (len) {
4486                 /*
4487                  * Recalculate credits when extent tree depth changes.
4488                  */
4489                 if (depth != ext_depth(inode)) {
4490                         credits = ext4_chunk_trans_blocks(inode, len);
4491                         depth = ext_depth(inode);
4492                 }
4493
4494                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4495                                             credits);
4496                 if (IS_ERR(handle)) {
4497                         ret = PTR_ERR(handle);
4498                         break;
4499                 }
4500                 ret = ext4_map_blocks(handle, inode, &map, flags);
4501                 if (ret <= 0) {
4502                         ext4_debug("inode #%lu: block %u: len %u: "
4503                                    "ext4_ext_map_blocks returned %d",
4504                                    inode->i_ino, map.m_lblk,
4505                                    map.m_len, ret);
4506                         ext4_mark_inode_dirty(handle, inode);
4507                         ext4_journal_stop(handle);
4508                         break;
4509                 }
4510                 /*
4511                  * allow a full retry cycle for any remaining allocations
4512                  */
4513                 retries = 0;
4514                 map.m_lblk += ret;
4515                 map.m_len = len = len - ret;
4516                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4517                 inode->i_ctime = current_time(inode);
4518                 if (new_size) {
4519                         if (epos > new_size)
4520                                 epos = new_size;
4521                         if (ext4_update_inode_size(inode, epos) & 0x1)
4522                                 inode->i_mtime = inode->i_ctime;
4523                 }
4524                 ret2 = ext4_mark_inode_dirty(handle, inode);
4525                 ext4_update_inode_fsync_trans(handle, inode, 1);
4526                 ret3 = ext4_journal_stop(handle);
4527                 ret2 = ret3 ? ret3 : ret2;
4528                 if (unlikely(ret2))
4529                         break;
4530         }
4531         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
4532                 goto retry;
4533
4534         return ret > 0 ? ret2 : ret;
4535 }
4536
4537 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);
4538
4539 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
4540
4541 static long ext4_zero_range(struct file *file, loff_t offset,
4542                             loff_t len, int mode)
4543 {
4544         struct inode *inode = file_inode(file);
4545         struct address_space *mapping = file->f_mapping;
4546         handle_t *handle = NULL;
4547         unsigned int max_blocks;
4548         loff_t new_size = 0;
4549         int ret = 0;
4550         int flags;
4551         int credits;
4552         int partial_begin, partial_end;
4553         loff_t start, end;
4554         ext4_lblk_t lblk;
4555         unsigned int blkbits = inode->i_blkbits;
4556
4557         trace_ext4_zero_range(inode, offset, len, mode);
4558
4559         /* Call ext4_force_commit to flush all data in case of data=journal. */
4560         if (ext4_should_journal_data(inode)) {
4561                 ret = ext4_force_commit(inode->i_sb);
4562                 if (ret)
4563                         return ret;
4564         }
4565
4566         /*
4567          * Round up offset. This is not fallocate, we need to zero out
4568          * blocks, so convert interior block aligned part of the range to
4569          * unwritten and possibly manually zero out unaligned parts of the
4570          * range.
4571          */
4572         start = round_up(offset, 1 << blkbits);
4573         end = round_down((offset + len), 1 << blkbits);
4574
4575         if (start < offset || end > offset + len)
4576                 return -EINVAL;
4577         partial_begin = offset & ((1 << blkbits) - 1);
4578         partial_end = (offset + len) & ((1 << blkbits) - 1);
4579
4580         lblk = start >> blkbits;
4581         max_blocks = (end >> blkbits);
4582         if (max_blocks < lblk)
4583                 max_blocks = 0;
4584         else
4585                 max_blocks -= lblk;
4586
4587         inode_lock(inode);
4588
4589         /*
4590          * Indirect files do not support unwritten extents
4591          */
4592         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4593                 ret = -EOPNOTSUPP;
4594                 goto out_mutex;
4595         }
4596
4597         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4598             (offset + len > inode->i_size ||
4599              offset + len > EXT4_I(inode)->i_disksize)) {
4600                 new_size = offset + len;
4601                 ret = inode_newsize_ok(inode, new_size);
4602                 if (ret)
4603                         goto out_mutex;
4604         }
4605
4606         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4607
4608         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4609         inode_dio_wait(inode);
4610
4611         ret = file_modified(file);
4612         if (ret)
4613                 goto out_mutex;
4614
4615         /* Preallocate the range including the unaligned edges */
4616         if (partial_begin || partial_end) {
4617                 ret = ext4_alloc_file_blocks(file,
4618                                 round_down(offset, 1 << blkbits) >> blkbits,
4619                                 (round_up((offset + len), 1 << blkbits) -
4620                                  round_down(offset, 1 << blkbits)) >> blkbits,
4621                                 new_size, flags);
4622                 if (ret)
4623                         goto out_mutex;
4624
4625         }
4626
4627         /* Zero range excluding the unaligned edges */
4628         if (max_blocks > 0) {
4629                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4630                           EXT4_EX_NOCACHE);
4631
4632                 /*
4633                  * Prevent page faults from reinstantiating pages we have
4634                  * released from page cache.
4635                  */
4636                 filemap_invalidate_lock(mapping);
4637
4638                 ret = ext4_break_layouts(inode);
4639                 if (ret) {
4640                         filemap_invalidate_unlock(mapping);
4641                         goto out_mutex;
4642                 }
4643
4644                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4645                 if (ret) {
4646                         filemap_invalidate_unlock(mapping);
4647                         goto out_mutex;
4648                 }
4649                 /* Now release the pages and zero block aligned part of pages */
4650                 truncate_pagecache_range(inode, start, end - 1);
4651                 inode->i_mtime = inode->i_ctime = current_time(inode);
4652
4653                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4654                                              flags);
4655                 filemap_invalidate_unlock(mapping);
4656                 if (ret)
4657                         goto out_mutex;
4658         }
4659         if (!partial_begin && !partial_end)
4660                 goto out_mutex;
4661
4662         /*
4663          * In worst case we have to writeout two nonadjacent unwritten
4664          * blocks and update the inode
4665          */
4666         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4667         if (ext4_should_journal_data(inode))
4668                 credits += 2;
4669         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4670         if (IS_ERR(handle)) {
4671                 ret = PTR_ERR(handle);
4672                 ext4_std_error(inode->i_sb, ret);
4673                 goto out_mutex;
4674         }
4675
4676         inode->i_mtime = inode->i_ctime = current_time(inode);
4677         if (new_size)
4678                 ext4_update_inode_size(inode, new_size);
4679         ret = ext4_mark_inode_dirty(handle, inode);
4680         if (unlikely(ret))
4681                 goto out_handle;
4682         /* Zero out partial block at the edges of the range */
4683         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4684         if (ret >= 0)
4685                 ext4_update_inode_fsync_trans(handle, inode, 1);
4686
4687         if (file->f_flags & O_SYNC)
4688                 ext4_handle_sync(handle);
4689
4690 out_handle:
4691         ext4_journal_stop(handle);
4692 out_mutex:
4693         inode_unlock(inode);
4694         return ret;
4695 }
4696
4697 /*
4698  * preallocate space for a file. This implements ext4's fallocate file
4699  * operation, which gets called from sys_fallocate system call.
4700  * For block-mapped files, posix_fallocate should fall back to the method
4701  * of writing zeroes to the required new blocks (the same behavior which is
4702  * expected for file systems which do not support fallocate() system call).
4703  */
4704 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4705 {
4706         struct inode *inode = file_inode(file);
4707         loff_t new_size = 0;
4708         unsigned int max_blocks;
4709         int ret = 0;
4710         int flags;
4711         ext4_lblk_t lblk;
4712         unsigned int blkbits = inode->i_blkbits;
4713
4714         /*
4715          * Encrypted inodes can't handle collapse range or insert
4716          * range since we would need to re-encrypt blocks with a
4717          * different IV or XTS tweak (which are based on the logical
4718          * block number).
4719          */
4720         if (IS_ENCRYPTED(inode) &&
4721             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
4722                 return -EOPNOTSUPP;
4723
4724         /* Return error if mode is not supported */
4725         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4726                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4727                      FALLOC_FL_INSERT_RANGE))
4728                 return -EOPNOTSUPP;
4729
4730         inode_lock(inode);
4731         ret = ext4_convert_inline_data(inode);
4732         inode_unlock(inode);
4733         if (ret)
4734                 goto exit;
4735
4736         if (mode & FALLOC_FL_PUNCH_HOLE) {
4737                 ret = ext4_punch_hole(file, offset, len);
4738                 goto exit;
4739         }
4740
4741         if (mode & FALLOC_FL_COLLAPSE_RANGE) {
4742                 ret = ext4_collapse_range(file, offset, len);
4743                 goto exit;
4744         }
4745
4746         if (mode & FALLOC_FL_INSERT_RANGE) {
4747                 ret = ext4_insert_range(file, offset, len);
4748                 goto exit;
4749         }
4750
4751         if (mode & FALLOC_FL_ZERO_RANGE) {
4752                 ret = ext4_zero_range(file, offset, len, mode);
4753                 goto exit;
4754         }
4755         trace_ext4_fallocate_enter(inode, offset, len, mode);
4756         lblk = offset >> blkbits;
4757
4758         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4759         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4760
4761         inode_lock(inode);
4762
4763         /*
4764          * We only support preallocation for extent-based files only
4765          */
4766         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4767                 ret = -EOPNOTSUPP;
4768                 goto out;
4769         }
4770
4771         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4772             (offset + len > inode->i_size ||
4773              offset + len > EXT4_I(inode)->i_disksize)) {
4774                 new_size = offset + len;
4775                 ret = inode_newsize_ok(inode, new_size);
4776                 if (ret)
4777                         goto out;
4778         }
4779
4780         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4781         inode_dio_wait(inode);
4782
4783         ret = file_modified(file);
4784         if (ret)
4785                 goto out;
4786
4787         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4788         if (ret)
4789                 goto out;
4790
4791         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4792                 ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
4793                                         EXT4_I(inode)->i_sync_tid);
4794         }
4795 out:
4796         inode_unlock(inode);
4797         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4798 exit:
4799         return ret;
4800 }
4801
4802 /*
4803  * This function convert a range of blocks to written extents
4804  * The caller of this function will pass the start offset and the size.
4805  * all unwritten extents within this range will be converted to
4806  * written extents.
4807  *
4808  * This function is called from the direct IO end io call back
4809  * function, to convert the fallocated extents after IO is completed.
4810  * Returns 0 on success.
4811  */
4812 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4813                                    loff_t offset, ssize_t len)
4814 {
4815         unsigned int max_blocks;
4816         int ret = 0, ret2 = 0, ret3 = 0;
4817         struct ext4_map_blocks map;
4818         unsigned int blkbits = inode->i_blkbits;
4819         unsigned int credits = 0;
4820
4821         map.m_lblk = offset >> blkbits;
4822         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4823
4824         if (!handle) {
4825                 /*
4826                  * credits to insert 1 extent into extent tree
4827                  */
4828                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4829         }
4830         while (ret >= 0 && ret < max_blocks) {
4831                 map.m_lblk += ret;
4832                 map.m_len = (max_blocks -= ret);
4833                 if (credits) {
4834                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4835                                                     credits);
4836                         if (IS_ERR(handle)) {
4837                                 ret = PTR_ERR(handle);
4838                                 break;
4839                         }
4840                 }
4841                 ret = ext4_map_blocks(handle, inode, &map,
4842                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4843                 if (ret <= 0)
4844                         ext4_warning(inode->i_sb,
4845                                      "inode #%lu: block %u: len %u: "
4846                                      "ext4_ext_map_blocks returned %d",
4847                                      inode->i_ino, map.m_lblk,
4848                                      map.m_len, ret);
4849                 ret2 = ext4_mark_inode_dirty(handle, inode);
4850                 if (credits) {
4851                         ret3 = ext4_journal_stop(handle);
4852                         if (unlikely(ret3))
4853                                 ret2 = ret3;
4854                 }
4855
4856                 if (ret <= 0 || ret2)
4857                         break;
4858         }
4859         return ret > 0 ? ret2 : ret;
4860 }
4861
4862 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
4863 {
4864         int ret = 0, err = 0;
4865         struct ext4_io_end_vec *io_end_vec;
4866
4867         /*
4868          * This is somewhat ugly but the idea is clear: When transaction is
4869          * reserved, everything goes into it. Otherwise we rather start several
4870          * smaller transactions for conversion of each extent separately.
4871          */
4872         if (handle) {
4873                 handle = ext4_journal_start_reserved(handle,
4874                                                      EXT4_HT_EXT_CONVERT);
4875                 if (IS_ERR(handle))
4876                         return PTR_ERR(handle);
4877         }
4878
4879         list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4880                 ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4881                                                      io_end_vec->offset,
4882                                                      io_end_vec->size);
4883                 if (ret)
4884                         break;
4885         }
4886
4887         if (handle)
4888                 err = ext4_journal_stop(handle);
4889
4890         return ret < 0 ? ret : err;
4891 }
4892
4893 static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
4894 {
4895         __u64 physical = 0;
4896         __u64 length = 0;
4897         int blockbits = inode->i_sb->s_blocksize_bits;
4898         int error = 0;
4899         u16 iomap_type;
4900
4901         /* in-inode? */
4902         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4903                 struct ext4_iloc iloc;
4904                 int offset;     /* offset of xattr in inode */
4905
4906                 error = ext4_get_inode_loc(inode, &iloc);
4907                 if (error)
4908                         return error;
4909                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
4910                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4911                                 EXT4_I(inode)->i_extra_isize;
4912                 physical += offset;
4913                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4914                 brelse(iloc.bh);
4915                 iomap_type = IOMAP_INLINE;
4916         } else if (EXT4_I(inode)->i_file_acl) { /* external block */
4917                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4918                 length = inode->i_sb->s_blocksize;
4919                 iomap_type = IOMAP_MAPPED;
4920         } else {
4921                 /* no in-inode or external block for xattr, so return -ENOENT */
4922                 error = -ENOENT;
4923                 goto out;
4924         }
4925
4926         iomap->addr = physical;
4927         iomap->offset = 0;
4928         iomap->length = length;
4929         iomap->type = iomap_type;
4930         iomap->flags = 0;
4931 out:
4932         return error;
4933 }
4934
4935 static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
4936                                   loff_t length, unsigned flags,
4937                                   struct iomap *iomap, struct iomap *srcmap)
4938 {
4939         int error;
4940
4941         error = ext4_iomap_xattr_fiemap(inode, iomap);
4942         if (error == 0 && (offset >= iomap->length))
4943                 error = -ENOENT;
4944         return error;
4945 }
4946
4947 static const struct iomap_ops ext4_iomap_xattr_ops = {
4948         .iomap_begin            = ext4_iomap_xattr_begin,
4949 };
4950
4951 static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
4952 {
4953         u64 maxbytes;
4954
4955         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4956                 maxbytes = inode->i_sb->s_maxbytes;
4957         else
4958                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
4959
4960         if (*len == 0)
4961                 return -EINVAL;
4962         if (start > maxbytes)
4963                 return -EFBIG;
4964
4965         /*
4966          * Shrink request scope to what the fs can actually handle.
4967          */
4968         if (*len > maxbytes || (maxbytes - *len) < start)
4969                 *len = maxbytes - start;
4970         return 0;
4971 }
4972
4973 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4974                 u64 start, u64 len)
4975 {
4976         int error = 0;
4977
4978         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4979                 error = ext4_ext_precache(inode);
4980                 if (error)
4981                         return error;
4982                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4983         }
4984
4985         /*
4986          * For bitmap files the maximum size limit could be smaller than
4987          * s_maxbytes, so check len here manually instead of just relying on the
4988          * generic check.
4989          */
4990         error = ext4_fiemap_check_ranges(inode, start, &len);
4991         if (error)
4992                 return error;
4993
4994         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4995                 fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
4996                 return iomap_fiemap(inode, fieinfo, start, len,
4997                                     &ext4_iomap_xattr_ops);
4998         }
4999
5000         return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
5001 }
5002
5003 int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
5004                       __u64 start, __u64 len)
5005 {
5006         ext4_lblk_t start_blk, len_blks;
5007         __u64 last_blk;
5008         int error = 0;
5009
5010         if (ext4_has_inline_data(inode)) {
5011                 int has_inline;
5012
5013                 down_read(&EXT4_I(inode)->xattr_sem);
5014                 has_inline = ext4_has_inline_data(inode);
5015                 up_read(&EXT4_I(inode)->xattr_sem);
5016                 if (has_inline)
5017                         return 0;
5018         }
5019
5020         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5021                 error = ext4_ext_precache(inode);
5022                 if (error)
5023                         return error;
5024                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
5025         }
5026
5027         error = fiemap_prep(inode, fieinfo, start, &len, 0);
5028         if (error)
5029                 return error;
5030
5031         error = ext4_fiemap_check_ranges(inode, start, &len);
5032         if (error)
5033                 return error;
5034
5035         start_blk = start >> inode->i_sb->s_blocksize_bits;
5036         last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5037         if (last_blk >= EXT_MAX_BLOCKS)
5038                 last_blk = EXT_MAX_BLOCKS-1;
5039         len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5040
5041         /*
5042          * Walk the extent tree gathering extent information
5043          * and pushing extents back to the user.
5044          */
5045         return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
5046 }
5047
5048 /*
5049  * ext4_ext_shift_path_extents:
5050  * Shift the extents of a path structure lying between path[depth].p_ext
5051  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5052  * if it is right shift or left shift operation.
5053  */
5054 static int
5055 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5056                             struct inode *inode, handle_t *handle,
5057                             enum SHIFT_DIRECTION SHIFT)
5058 {
5059         int depth, err = 0;
5060         struct ext4_extent *ex_start, *ex_last;
5061         bool update = false;
5062         int credits, restart_credits;
5063         depth = path->p_depth;
5064
5065         while (depth >= 0) {
5066                 if (depth == path->p_depth) {
5067                         ex_start = path[depth].p_ext;
5068                         if (!ex_start)
5069                                 return -EFSCORRUPTED;
5070
5071                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5072                         /* leaf + sb + inode */
5073                         credits = 3;
5074                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
5075                                 update = true;
5076                                 /* extent tree + sb + inode */
5077                                 credits = depth + 2;
5078                         }
5079
5080                         restart_credits = ext4_writepage_trans_blocks(inode);
5081                         err = ext4_datasem_ensure_credits(handle, inode, credits,
5082                                         restart_credits, 0);
5083                         if (err) {
5084                                 if (err > 0)
5085                                         err = -EAGAIN;
5086                                 goto out;
5087                         }
5088
5089                         err = ext4_ext_get_access(handle, inode, path + depth);
5090                         if (err)
5091                                 goto out;
5092
5093                         while (ex_start <= ex_last) {
5094                                 if (SHIFT == SHIFT_LEFT) {
5095                                         le32_add_cpu(&ex_start->ee_block,
5096                                                 -shift);
5097                                         /* Try to merge to the left. */
5098                                         if ((ex_start >
5099                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5100                                             &&
5101                                             ext4_ext_try_to_merge_right(inode,
5102                                             path, ex_start - 1))
5103                                                 ex_last--;
5104                                         else
5105                                                 ex_start++;
5106                                 } else {
5107                                         le32_add_cpu(&ex_last->ee_block, shift);
5108                                         ext4_ext_try_to_merge_right(inode, path,
5109                                                 ex_last);
5110                                         ex_last--;
5111                                 }
5112                         }
5113                         err = ext4_ext_dirty(handle, inode, path + depth);
5114                         if (err)
5115                                 goto out;
5116
5117                         if (--depth < 0 || !update)
5118                                 break;
5119                 }
5120
5121                 /* Update index too */
5122                 err = ext4_ext_get_access(handle, inode, path + depth);
5123                 if (err)
5124                         goto out;
5125
5126                 if (SHIFT == SHIFT_LEFT)
5127                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5128                 else
5129                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5130                 err = ext4_ext_dirty(handle, inode, path + depth);
5131                 if (err)
5132                         goto out;
5133
5134                 /* we are done if current index is not a starting index */
5135                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5136                         break;
5137
5138                 depth--;
5139         }
5140
5141 out:
5142         return err;
5143 }
5144
5145 /*
5146  * ext4_ext_shift_extents:
5147  * All the extents which lies in the range from @start to the last allocated
5148  * block for the @inode are shifted either towards left or right (depending
5149  * upon @SHIFT) by @shift blocks.
5150  * On success, 0 is returned, error otherwise.
5151  */
5152 static int
5153 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5154                        ext4_lblk_t start, ext4_lblk_t shift,
5155                        enum SHIFT_DIRECTION SHIFT)
5156 {
5157         struct ext4_ext_path *path;
5158         int ret = 0, depth;
5159         struct ext4_extent *extent;
5160         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5161         ext4_lblk_t tmp = EXT_MAX_BLOCKS;
5162
5163         /* Let path point to the last extent */
5164         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5165                                 EXT4_EX_NOCACHE);
5166         if (IS_ERR(path))
5167                 return PTR_ERR(path);
5168
5169         depth = path->p_depth;
5170         extent = path[depth].p_ext;
5171         if (!extent)
5172                 goto out;
5173
5174         stop = le32_to_cpu(extent->ee_block);
5175
5176        /*
5177         * For left shifts, make sure the hole on the left is big enough to
5178         * accommodate the shift.  For right shifts, make sure the last extent
5179         * won't be shifted beyond EXT_MAX_BLOCKS.
5180         */
5181         if (SHIFT == SHIFT_LEFT) {
5182                 path = ext4_find_extent(inode, start - 1, &path,
5183                                         EXT4_EX_NOCACHE);
5184                 if (IS_ERR(path))
5185                         return PTR_ERR(path);
5186                 depth = path->p_depth;
5187                 extent =  path[depth].p_ext;
5188                 if (extent) {
5189                         ex_start = le32_to_cpu(extent->ee_block);
5190                         ex_end = le32_to_cpu(extent->ee_block) +
5191                                 ext4_ext_get_actual_len(extent);
5192                 } else {
5193                         ex_start = 0;
5194                         ex_end = 0;
5195                 }
5196
5197                 if ((start == ex_start && shift > ex_start) ||
5198                     (shift > start - ex_end)) {
5199                         ret = -EINVAL;
5200                         goto out;
5201                 }
5202         } else {
5203                 if (shift > EXT_MAX_BLOCKS -
5204                     (stop + ext4_ext_get_actual_len(extent))) {
5205                         ret = -EINVAL;
5206                         goto out;
5207                 }
5208         }
5209
5210         /*
5211          * In case of left shift, iterator points to start and it is increased
5212          * till we reach stop. In case of right shift, iterator points to stop
5213          * and it is decreased till we reach start.
5214          */
5215 again:
5216         ret = 0;
5217         if (SHIFT == SHIFT_LEFT)
5218                 iterator = &start;
5219         else
5220                 iterator = &stop;
5221
5222         if (tmp != EXT_MAX_BLOCKS)
5223                 *iterator = tmp;
5224
5225         /*
5226          * Its safe to start updating extents.  Start and stop are unsigned, so
5227          * in case of right shift if extent with 0 block is reached, iterator
5228          * becomes NULL to indicate the end of the loop.
5229          */
5230         while (iterator && start <= stop) {
5231                 path = ext4_find_extent(inode, *iterator, &path,
5232                                         EXT4_EX_NOCACHE);
5233                 if (IS_ERR(path))
5234                         return PTR_ERR(path);
5235                 depth = path->p_depth;
5236                 extent = path[depth].p_ext;
5237                 if (!extent) {
5238                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5239                                          (unsigned long) *iterator);
5240                         return -EFSCORRUPTED;
5241                 }
5242                 if (SHIFT == SHIFT_LEFT && *iterator >
5243                     le32_to_cpu(extent->ee_block)) {
5244                         /* Hole, move to the next extent */
5245                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5246                                 path[depth].p_ext++;
5247                         } else {
5248                                 *iterator = ext4_ext_next_allocated_block(path);
5249                                 continue;
5250                         }
5251                 }
5252
5253                 tmp = *iterator;
5254                 if (SHIFT == SHIFT_LEFT) {
5255                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5256                         *iterator = le32_to_cpu(extent->ee_block) +
5257                                         ext4_ext_get_actual_len(extent);
5258                 } else {
5259                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5260                         if (le32_to_cpu(extent->ee_block) > start)
5261                                 *iterator = le32_to_cpu(extent->ee_block) - 1;
5262                         else if (le32_to_cpu(extent->ee_block) == start)
5263                                 iterator = NULL;
5264                         else {
5265                                 extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5266                                 while (le32_to_cpu(extent->ee_block) >= start)
5267                                         extent--;
5268
5269                                 if (extent == EXT_LAST_EXTENT(path[depth].p_hdr))
5270                                         break;
5271
5272                                 extent++;
5273                                 iterator = NULL;
5274                         }
5275                         path[depth].p_ext = extent;
5276                 }
5277                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5278                                 handle, SHIFT);
5279                 /* iterator can be NULL which means we should break */
5280                 if (ret == -EAGAIN)
5281                         goto again;
5282                 if (ret)
5283                         break;
5284         }
5285 out:
5286         ext4_free_ext_path(path);
5287         return ret;
5288 }
5289
5290 /*
5291  * ext4_collapse_range:
5292  * This implements the fallocate's collapse range functionality for ext4
5293  * Returns: 0 and non-zero on error.
5294  */
5295 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)
5296 {
5297         struct inode *inode = file_inode(file);
5298         struct super_block *sb = inode->i_sb;
5299         struct address_space *mapping = inode->i_mapping;
5300         ext4_lblk_t punch_start, punch_stop;
5301         handle_t *handle;
5302         unsigned int credits;
5303         loff_t new_size, ioffset;
5304         int ret;
5305
5306         /*
5307          * We need to test this early because xfstests assumes that a
5308          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5309          * system does not support collapse range.
5310          */
5311         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5312                 return -EOPNOTSUPP;
5313
5314         /* Collapse range works only on fs cluster size aligned regions. */
5315         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5316                 return -EINVAL;
5317
5318         trace_ext4_collapse_range(inode, offset, len);
5319
5320         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5321         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5322
5323         /* Call ext4_force_commit to flush all data in case of data=journal. */
5324         if (ext4_should_journal_data(inode)) {
5325                 ret = ext4_force_commit(inode->i_sb);
5326                 if (ret)
5327                         return ret;
5328         }
5329
5330         inode_lock(inode);
5331         /*
5332          * There is no need to overlap collapse range with EOF, in which case
5333          * it is effectively a truncate operation
5334          */
5335         if (offset + len >= inode->i_size) {
5336                 ret = -EINVAL;
5337                 goto out_mutex;
5338         }
5339
5340         /* Currently just for extent based files */
5341         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5342                 ret = -EOPNOTSUPP;
5343                 goto out_mutex;
5344         }
5345
5346         /* Wait for existing dio to complete */
5347         inode_dio_wait(inode);
5348
5349         ret = file_modified(file);
5350         if (ret)
5351                 goto out_mutex;
5352
5353         /*
5354          * Prevent page faults from reinstantiating pages we have released from
5355          * page cache.
5356          */
5357         filemap_invalidate_lock(mapping);
5358
5359         ret = ext4_break_layouts(inode);
5360         if (ret)
5361                 goto out_mmap;
5362
5363         /*
5364          * Need to round down offset to be aligned with page size boundary
5365          * for page size > block size.
5366          */
5367         ioffset = round_down(offset, PAGE_SIZE);
5368         /*
5369          * Write tail of the last page before removed range since it will get
5370          * removed from the page cache below.
5371          */
5372         ret = filemap_write_and_wait_range(mapping, ioffset, offset);
5373         if (ret)
5374                 goto out_mmap;
5375         /*
5376          * Write data that will be shifted to preserve them when discarding
5377          * page cache below. We are also protected from pages becoming dirty
5378          * by i_rwsem and invalidate_lock.
5379          */
5380         ret = filemap_write_and_wait_range(mapping, offset + len,
5381                                            LLONG_MAX);
5382         if (ret)
5383                 goto out_mmap;
5384         truncate_pagecache(inode, ioffset);
5385
5386         credits = ext4_writepage_trans_blocks(inode);
5387         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5388         if (IS_ERR(handle)) {
5389                 ret = PTR_ERR(handle);
5390                 goto out_mmap;
5391         }
5392         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5393
5394         down_write(&EXT4_I(inode)->i_data_sem);
5395         ext4_discard_preallocations(inode, 0);
5396
5397         ret = ext4_es_remove_extent(inode, punch_start,
5398                                     EXT_MAX_BLOCKS - punch_start);
5399         if (ret) {
5400                 up_write(&EXT4_I(inode)->i_data_sem);
5401                 goto out_stop;
5402         }
5403
5404         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5405         if (ret) {
5406                 up_write(&EXT4_I(inode)->i_data_sem);
5407                 goto out_stop;
5408         }
5409         ext4_discard_preallocations(inode, 0);
5410
5411         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5412                                      punch_stop - punch_start, SHIFT_LEFT);
5413         if (ret) {
5414                 up_write(&EXT4_I(inode)->i_data_sem);
5415                 goto out_stop;
5416         }
5417
5418         new_size = inode->i_size - len;
5419         i_size_write(inode, new_size);
5420         EXT4_I(inode)->i_disksize = new_size;
5421
5422         up_write(&EXT4_I(inode)->i_data_sem);
5423         if (IS_SYNC(inode))
5424                 ext4_handle_sync(handle);
5425         inode->i_mtime = inode->i_ctime = current_time(inode);
5426         ret = ext4_mark_inode_dirty(handle, inode);
5427         ext4_update_inode_fsync_trans(handle, inode, 1);
5428
5429 out_stop:
5430         ext4_journal_stop(handle);
5431 out_mmap:
5432         filemap_invalidate_unlock(mapping);
5433 out_mutex:
5434         inode_unlock(inode);
5435         return ret;
5436 }
5437
5438 /*
5439  * ext4_insert_range:
5440  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5441  * The data blocks starting from @offset to the EOF are shifted by @len
5442  * towards right to create a hole in the @inode. Inode size is increased
5443  * by len bytes.
5444  * Returns 0 on success, error otherwise.
5445  */
5446 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
5447 {
5448         struct inode *inode = file_inode(file);
5449         struct super_block *sb = inode->i_sb;
5450         struct address_space *mapping = inode->i_mapping;
5451         handle_t *handle;
5452         struct ext4_ext_path *path;
5453         struct ext4_extent *extent;
5454         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5455         unsigned int credits, ee_len;
5456         int ret = 0, depth, split_flag = 0;
5457         loff_t ioffset;
5458
5459         /*
5460          * We need to test this early because xfstests assumes that an
5461          * insert range of (0, 1) will return EOPNOTSUPP if the file
5462          * system does not support insert range.
5463          */
5464         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5465                 return -EOPNOTSUPP;
5466
5467         /* Insert range works only on fs cluster size aligned regions. */
5468         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5469                 return -EINVAL;
5470
5471         trace_ext4_insert_range(inode, offset, len);
5472
5473         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5474         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5475
5476         /* Call ext4_force_commit to flush all data in case of data=journal */
5477         if (ext4_should_journal_data(inode)) {
5478                 ret = ext4_force_commit(inode->i_sb);
5479                 if (ret)
5480                         return ret;
5481         }
5482
5483         inode_lock(inode);
5484         /* Currently just for extent based files */
5485         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5486                 ret = -EOPNOTSUPP;
5487                 goto out_mutex;
5488         }
5489
5490         /* Check whether the maximum file size would be exceeded */
5491         if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5492                 ret = -EFBIG;
5493                 goto out_mutex;
5494         }
5495
5496         /* Offset must be less than i_size */
5497         if (offset >= inode->i_size) {
5498                 ret = -EINVAL;
5499                 goto out_mutex;
5500         }
5501
5502         /* Wait for existing dio to complete */
5503         inode_dio_wait(inode);
5504
5505         ret = file_modified(file);
5506         if (ret)
5507                 goto out_mutex;
5508
5509         /*
5510          * Prevent page faults from reinstantiating pages we have released from
5511          * page cache.
5512          */
5513         filemap_invalidate_lock(mapping);
5514
5515         ret = ext4_break_layouts(inode);
5516         if (ret)
5517                 goto out_mmap;
5518
5519         /*
5520          * Need to round down to align start offset to page size boundary
5521          * for page size > block size.
5522          */
5523         ioffset = round_down(offset, PAGE_SIZE);
5524         /* Write out all dirty pages */
5525         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5526                         LLONG_MAX);
5527         if (ret)
5528                 goto out_mmap;
5529         truncate_pagecache(inode, ioffset);
5530
5531         credits = ext4_writepage_trans_blocks(inode);
5532         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5533         if (IS_ERR(handle)) {
5534                 ret = PTR_ERR(handle);
5535                 goto out_mmap;
5536         }
5537         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5538
5539         /* Expand file to avoid data loss if there is error while shifting */
5540         inode->i_size += len;
5541         EXT4_I(inode)->i_disksize += len;
5542         inode->i_mtime = inode->i_ctime = current_time(inode);
5543         ret = ext4_mark_inode_dirty(handle, inode);
5544         if (ret)
5545                 goto out_stop;
5546
5547         down_write(&EXT4_I(inode)->i_data_sem);
5548         ext4_discard_preallocations(inode, 0);
5549
5550         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5551         if (IS_ERR(path)) {
5552                 up_write(&EXT4_I(inode)->i_data_sem);
5553                 goto out_stop;
5554         }
5555
5556         depth = ext_depth(inode);
5557         extent = path[depth].p_ext;
5558         if (extent) {
5559                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5560                 ee_len = ext4_ext_get_actual_len(extent);
5561
5562                 /*
5563                  * If offset_lblk is not the starting block of extent, split
5564                  * the extent @offset_lblk
5565                  */
5566                 if ((offset_lblk > ee_start_lblk) &&
5567                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5568                         if (ext4_ext_is_unwritten(extent))
5569                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5570                                         EXT4_EXT_MARK_UNWRIT2;
5571                         ret = ext4_split_extent_at(handle, inode, &path,
5572                                         offset_lblk, split_flag,
5573                                         EXT4_EX_NOCACHE |
5574                                         EXT4_GET_BLOCKS_PRE_IO |
5575                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5576                 }
5577
5578                 ext4_free_ext_path(path);
5579                 if (ret < 0) {
5580                         up_write(&EXT4_I(inode)->i_data_sem);
5581                         goto out_stop;
5582                 }
5583         } else {
5584                 ext4_free_ext_path(path);
5585         }
5586
5587         ret = ext4_es_remove_extent(inode, offset_lblk,
5588                         EXT_MAX_BLOCKS - offset_lblk);
5589         if (ret) {
5590                 up_write(&EXT4_I(inode)->i_data_sem);
5591                 goto out_stop;
5592         }
5593
5594         /*
5595          * if offset_lblk lies in a hole which is at start of file, use
5596          * ee_start_lblk to shift extents
5597          */
5598         ret = ext4_ext_shift_extents(inode, handle,
5599                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5600                 len_lblk, SHIFT_RIGHT);
5601
5602         up_write(&EXT4_I(inode)->i_data_sem);
5603         if (IS_SYNC(inode))
5604                 ext4_handle_sync(handle);
5605         if (ret >= 0)
5606                 ext4_update_inode_fsync_trans(handle, inode, 1);
5607
5608 out_stop:
5609         ext4_journal_stop(handle);
5610 out_mmap:
5611         filemap_invalidate_unlock(mapping);
5612 out_mutex:
5613         inode_unlock(inode);
5614         return ret;
5615 }
5616
5617 /**
5618  * ext4_swap_extents() - Swap extents between two inodes
5619  * @handle: handle for this transaction
5620  * @inode1:     First inode
5621  * @inode2:     Second inode
5622  * @lblk1:      Start block for first inode
5623  * @lblk2:      Start block for second inode
5624  * @count:      Number of blocks to swap
5625  * @unwritten: Mark second inode's extents as unwritten after swap
5626  * @erp:        Pointer to save error value
5627  *
5628  * This helper routine does exactly what is promise "swap extents". All other
5629  * stuff such as page-cache locking consistency, bh mapping consistency or
5630  * extent's data copying must be performed by caller.
5631  * Locking:
5632  *              i_rwsem is held for both inodes
5633  *              i_data_sem is locked for write for both inodes
5634  * Assumptions:
5635  *              All pages from requested range are locked for both inodes
5636  */
5637 int
5638 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5639                   struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5640                   ext4_lblk_t count, int unwritten, int *erp)
5641 {
5642         struct ext4_ext_path *path1 = NULL;
5643         struct ext4_ext_path *path2 = NULL;
5644         int replaced_count = 0;
5645
5646         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5647         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5648         BUG_ON(!inode_is_locked(inode1));
5649         BUG_ON(!inode_is_locked(inode2));
5650
5651         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5652         if (unlikely(*erp))
5653                 return 0;
5654         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5655         if (unlikely(*erp))
5656                 return 0;
5657
5658         while (count) {
5659                 struct ext4_extent *ex1, *ex2, tmp_ex;
5660                 ext4_lblk_t e1_blk, e2_blk;
5661                 int e1_len, e2_len, len;
5662                 int split = 0;
5663
5664                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5665                 if (IS_ERR(path1)) {
5666                         *erp = PTR_ERR(path1);
5667                         path1 = NULL;
5668                 finish:
5669                         count = 0;
5670                         goto repeat;
5671                 }
5672                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5673                 if (IS_ERR(path2)) {
5674                         *erp = PTR_ERR(path2);
5675                         path2 = NULL;
5676                         goto finish;
5677                 }
5678                 ex1 = path1[path1->p_depth].p_ext;
5679                 ex2 = path2[path2->p_depth].p_ext;
5680                 /* Do we have something to swap ? */
5681                 if (unlikely(!ex2 || !ex1))
5682                         goto finish;
5683
5684                 e1_blk = le32_to_cpu(ex1->ee_block);
5685                 e2_blk = le32_to_cpu(ex2->ee_block);
5686                 e1_len = ext4_ext_get_actual_len(ex1);
5687                 e2_len = ext4_ext_get_actual_len(ex2);
5688
5689                 /* Hole handling */
5690                 if (!in_range(lblk1, e1_blk, e1_len) ||
5691                     !in_range(lblk2, e2_blk, e2_len)) {
5692                         ext4_lblk_t next1, next2;
5693
5694                         /* if hole after extent, then go to next extent */
5695                         next1 = ext4_ext_next_allocated_block(path1);
5696                         next2 = ext4_ext_next_allocated_block(path2);
5697                         /* If hole before extent, then shift to that extent */
5698                         if (e1_blk > lblk1)
5699                                 next1 = e1_blk;
5700                         if (e2_blk > lblk2)
5701                                 next2 = e2_blk;
5702                         /* Do we have something to swap */
5703                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5704                                 goto finish;
5705                         /* Move to the rightest boundary */
5706                         len = next1 - lblk1;
5707                         if (len < next2 - lblk2)
5708                                 len = next2 - lblk2;
5709                         if (len > count)
5710                                 len = count;
5711                         lblk1 += len;
5712                         lblk2 += len;
5713                         count -= len;
5714                         goto repeat;
5715                 }
5716
5717                 /* Prepare left boundary */
5718                 if (e1_blk < lblk1) {
5719                         split = 1;
5720                         *erp = ext4_force_split_extent_at(handle, inode1,
5721                                                 &path1, lblk1, 0);
5722                         if (unlikely(*erp))
5723                                 goto finish;
5724                 }
5725                 if (e2_blk < lblk2) {
5726                         split = 1;
5727                         *erp = ext4_force_split_extent_at(handle, inode2,
5728                                                 &path2,  lblk2, 0);
5729                         if (unlikely(*erp))
5730                                 goto finish;
5731                 }
5732                 /* ext4_split_extent_at() may result in leaf extent split,
5733                  * path must to be revalidated. */
5734                 if (split)
5735                         goto repeat;
5736
5737                 /* Prepare right boundary */
5738                 len = count;
5739                 if (len > e1_blk + e1_len - lblk1)
5740                         len = e1_blk + e1_len - lblk1;
5741                 if (len > e2_blk + e2_len - lblk2)
5742                         len = e2_blk + e2_len - lblk2;
5743
5744                 if (len != e1_len) {
5745                         split = 1;
5746                         *erp = ext4_force_split_extent_at(handle, inode1,
5747                                                 &path1, lblk1 + len, 0);
5748                         if (unlikely(*erp))
5749                                 goto finish;
5750                 }
5751                 if (len != e2_len) {
5752                         split = 1;
5753                         *erp = ext4_force_split_extent_at(handle, inode2,
5754                                                 &path2, lblk2 + len, 0);
5755                         if (*erp)
5756                                 goto finish;
5757                 }
5758                 /* ext4_split_extent_at() may result in leaf extent split,
5759                  * path must to be revalidated. */
5760                 if (split)
5761                         goto repeat;
5762
5763                 BUG_ON(e2_len != e1_len);
5764                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5765                 if (unlikely(*erp))
5766                         goto finish;
5767                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5768                 if (unlikely(*erp))
5769                         goto finish;
5770
5771                 /* Both extents are fully inside boundaries. Swap it now */
5772                 tmp_ex = *ex1;
5773                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5774                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5775                 ex1->ee_len = cpu_to_le16(e2_len);
5776                 ex2->ee_len = cpu_to_le16(e1_len);
5777                 if (unwritten)
5778                         ext4_ext_mark_unwritten(ex2);
5779                 if (ext4_ext_is_unwritten(&tmp_ex))
5780                         ext4_ext_mark_unwritten(ex1);
5781
5782                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5783                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5784                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5785                                       path2->p_depth);
5786                 if (unlikely(*erp))
5787                         goto finish;
5788                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5789                                       path1->p_depth);
5790                 /*
5791                  * Looks scarry ah..? second inode already points to new blocks,
5792                  * and it was successfully dirtied. But luckily error may happen
5793                  * only due to journal error, so full transaction will be
5794                  * aborted anyway.
5795                  */
5796                 if (unlikely(*erp))
5797                         goto finish;
5798                 lblk1 += len;
5799                 lblk2 += len;
5800                 replaced_count += len;
5801                 count -= len;
5802
5803         repeat:
5804                 ext4_free_ext_path(path1);
5805                 ext4_free_ext_path(path2);
5806                 path1 = path2 = NULL;
5807         }
5808         return replaced_count;
5809 }
5810
5811 /*
5812  * ext4_clu_mapped - determine whether any block in a logical cluster has
5813  *                   been mapped to a physical cluster
5814  *
5815  * @inode - file containing the logical cluster
5816  * @lclu - logical cluster of interest
5817  *
5818  * Returns 1 if any block in the logical cluster is mapped, signifying
5819  * that a physical cluster has been allocated for it.  Otherwise,
5820  * returns 0.  Can also return negative error codes.  Derived from
5821  * ext4_ext_map_blocks().
5822  */
5823 int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5824 {
5825         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5826         struct ext4_ext_path *path;
5827         int depth, mapped = 0, err = 0;
5828         struct ext4_extent *extent;
5829         ext4_lblk_t first_lblk, first_lclu, last_lclu;
5830
5831         /*
5832          * if data can be stored inline, the logical cluster isn't
5833          * mapped - no physical clusters have been allocated, and the
5834          * file has no extents
5835          */
5836         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) ||
5837             ext4_has_inline_data(inode))
5838                 return 0;
5839
5840         /* search for the extent closest to the first block in the cluster */
5841         path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5842         if (IS_ERR(path)) {
5843                 err = PTR_ERR(path);
5844                 path = NULL;
5845                 goto out;
5846         }
5847
5848         depth = ext_depth(inode);
5849
5850         /*
5851          * A consistent leaf must not be empty.  This situation is possible,
5852          * though, _during_ tree modification, and it's why an assert can't
5853          * be put in ext4_find_extent().
5854          */
5855         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5856                 EXT4_ERROR_INODE(inode,
5857                     "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5858                                  (unsigned long) EXT4_C2B(sbi, lclu),
5859                                  depth, path[depth].p_block);
5860                 err = -EFSCORRUPTED;
5861                 goto out;
5862         }
5863
5864         extent = path[depth].p_ext;
5865
5866         /* can't be mapped if the extent tree is empty */
5867         if (extent == NULL)
5868                 goto out;
5869
5870         first_lblk = le32_to_cpu(extent->ee_block);
5871         first_lclu = EXT4_B2C(sbi, first_lblk);
5872
5873         /*
5874          * Three possible outcomes at this point - found extent spanning
5875          * the target cluster, to the left of the target cluster, or to the
5876          * right of the target cluster.  The first two cases are handled here.
5877          * The last case indicates the target cluster is not mapped.
5878          */
5879         if (lclu >= first_lclu) {
5880                 last_lclu = EXT4_B2C(sbi, first_lblk +
5881                                      ext4_ext_get_actual_len(extent) - 1);
5882                 if (lclu <= last_lclu) {
5883                         mapped = 1;
5884                 } else {
5885                         first_lblk = ext4_ext_next_allocated_block(path);
5886                         first_lclu = EXT4_B2C(sbi, first_lblk);
5887                         if (lclu == first_lclu)
5888                                 mapped = 1;
5889                 }
5890         }
5891
5892 out:
5893         ext4_free_ext_path(path);
5894
5895         return err ? err : mapped;
5896 }
5897
5898 /*
5899  * Updates physical block address and unwritten status of extent
5900  * starting at lblk start and of len. If such an extent doesn't exist,
5901  * this function splits the extent tree appropriately to create an
5902  * extent like this.  This function is called in the fast commit
5903  * replay path.  Returns 0 on success and error on failure.
5904  */
5905 int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
5906                               int len, int unwritten, ext4_fsblk_t pblk)
5907 {
5908         struct ext4_ext_path *path = NULL, *ppath;
5909         struct ext4_extent *ex;
5910         int ret;
5911
5912         path = ext4_find_extent(inode, start, NULL, 0);
5913         if (IS_ERR(path))
5914                 return PTR_ERR(path);
5915         ex = path[path->p_depth].p_ext;
5916         if (!ex) {
5917                 ret = -EFSCORRUPTED;
5918                 goto out;
5919         }
5920
5921         if (le32_to_cpu(ex->ee_block) != start ||
5922                 ext4_ext_get_actual_len(ex) != len) {
5923                 /* We need to split this extent to match our extent first */
5924                 ppath = path;
5925                 down_write(&EXT4_I(inode)->i_data_sem);
5926                 ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
5927                 up_write(&EXT4_I(inode)->i_data_sem);
5928                 if (ret)
5929                         goto out;
5930                 kfree(path);
5931                 path = ext4_find_extent(inode, start, NULL, 0);
5932                 if (IS_ERR(path))
5933                         return -1;
5934                 ppath = path;
5935                 ex = path[path->p_depth].p_ext;
5936                 WARN_ON(le32_to_cpu(ex->ee_block) != start);
5937                 if (ext4_ext_get_actual_len(ex) != len) {
5938                         down_write(&EXT4_I(inode)->i_data_sem);
5939                         ret = ext4_force_split_extent_at(NULL, inode, &ppath,
5940                                                          start + len, 1);
5941                         up_write(&EXT4_I(inode)->i_data_sem);
5942                         if (ret)
5943                                 goto out;
5944                         kfree(path);
5945                         path = ext4_find_extent(inode, start, NULL, 0);
5946                         if (IS_ERR(path))
5947                                 return -EINVAL;
5948                         ex = path[path->p_depth].p_ext;
5949                 }
5950         }
5951         if (unwritten)
5952                 ext4_ext_mark_unwritten(ex);
5953         else
5954                 ext4_ext_mark_initialized(ex);
5955         ext4_ext_store_pblock(ex, pblk);
5956         down_write(&EXT4_I(inode)->i_data_sem);
5957         ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5958         up_write(&EXT4_I(inode)->i_data_sem);
5959 out:
5960         ext4_free_ext_path(path);
5961         ext4_mark_inode_dirty(NULL, inode);
5962         return ret;
5963 }
5964
5965 /* Try to shrink the extent tree */
5966 void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
5967 {
5968         struct ext4_ext_path *path = NULL;
5969         struct ext4_extent *ex;
5970         ext4_lblk_t old_cur, cur = 0;
5971
5972         while (cur < end) {
5973                 path = ext4_find_extent(inode, cur, NULL, 0);
5974                 if (IS_ERR(path))
5975                         return;
5976                 ex = path[path->p_depth].p_ext;
5977                 if (!ex) {
5978                         ext4_free_ext_path(path);
5979                         ext4_mark_inode_dirty(NULL, inode);
5980                         return;
5981                 }
5982                 old_cur = cur;
5983                 cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5984                 if (cur <= old_cur)
5985                         cur = old_cur + 1;
5986                 ext4_ext_try_to_merge(NULL, inode, path, ex);
5987                 down_write(&EXT4_I(inode)->i_data_sem);
5988                 ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5989                 up_write(&EXT4_I(inode)->i_data_sem);
5990                 ext4_mark_inode_dirty(NULL, inode);
5991                 ext4_free_ext_path(path);
5992         }
5993 }
5994
5995 /* Check if *cur is a hole and if it is, skip it */
5996 static int skip_hole(struct inode *inode, ext4_lblk_t *cur)
5997 {
5998         int ret;
5999         struct ext4_map_blocks map;
6000
6001         map.m_lblk = *cur;
6002         map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
6003
6004         ret = ext4_map_blocks(NULL, inode, &map, 0);
6005         if (ret < 0)
6006                 return ret;
6007         if (ret != 0)
6008                 return 0;
6009         *cur = *cur + map.m_len;
6010         return 0;
6011 }
6012
6013 /* Count number of blocks used by this inode and update i_blocks */
6014 int ext4_ext_replay_set_iblocks(struct inode *inode)
6015 {
6016         struct ext4_ext_path *path = NULL, *path2 = NULL;
6017         struct ext4_extent *ex;
6018         ext4_lblk_t cur = 0, end;
6019         int numblks = 0, i, ret = 0;
6020         ext4_fsblk_t cmp1, cmp2;
6021         struct ext4_map_blocks map;
6022
6023         /* Determin the size of the file first */
6024         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6025                                         EXT4_EX_NOCACHE);
6026         if (IS_ERR(path))
6027                 return PTR_ERR(path);
6028         ex = path[path->p_depth].p_ext;
6029         if (!ex) {
6030                 ext4_free_ext_path(path);
6031                 goto out;
6032         }
6033         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6034         ext4_free_ext_path(path);
6035
6036         /* Count the number of data blocks */
6037         cur = 0;
6038         while (cur < end) {
6039                 map.m_lblk = cur;
6040                 map.m_len = end - cur;
6041                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6042                 if (ret < 0)
6043                         break;
6044                 if (ret > 0)
6045                         numblks += ret;
6046                 cur = cur + map.m_len;
6047         }
6048
6049         /*
6050          * Count the number of extent tree blocks. We do it by looking up
6051          * two successive extents and determining the difference between
6052          * their paths. When path is different for 2 successive extents
6053          * we compare the blocks in the path at each level and increment
6054          * iblocks by total number of differences found.
6055          */
6056         cur = 0;
6057         ret = skip_hole(inode, &cur);
6058         if (ret < 0)
6059                 goto out;
6060         path = ext4_find_extent(inode, cur, NULL, 0);
6061         if (IS_ERR(path))
6062                 goto out;
6063         numblks += path->p_depth;
6064         ext4_free_ext_path(path);
6065         while (cur < end) {
6066                 path = ext4_find_extent(inode, cur, NULL, 0);
6067                 if (IS_ERR(path))
6068                         break;
6069                 ex = path[path->p_depth].p_ext;
6070                 if (!ex) {
6071                         ext4_free_ext_path(path);
6072                         return 0;
6073                 }
6074                 cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
6075                                         ext4_ext_get_actual_len(ex));
6076                 ret = skip_hole(inode, &cur);
6077                 if (ret < 0) {
6078                         ext4_free_ext_path(path);
6079                         break;
6080                 }
6081                 path2 = ext4_find_extent(inode, cur, NULL, 0);
6082                 if (IS_ERR(path2)) {
6083                         ext4_free_ext_path(path);
6084                         break;
6085                 }
6086                 for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
6087                         cmp1 = cmp2 = 0;
6088                         if (i <= path->p_depth)
6089                                 cmp1 = path[i].p_bh ?
6090                                         path[i].p_bh->b_blocknr : 0;
6091                         if (i <= path2->p_depth)
6092                                 cmp2 = path2[i].p_bh ?
6093                                         path2[i].p_bh->b_blocknr : 0;
6094                         if (cmp1 != cmp2 && cmp2 != 0)
6095                                 numblks++;
6096                 }
6097                 ext4_free_ext_path(path);
6098                 ext4_free_ext_path(path2);
6099         }
6100
6101 out:
6102         inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
6103         ext4_mark_inode_dirty(NULL, inode);
6104         return 0;
6105 }
6106
6107 int ext4_ext_clear_bb(struct inode *inode)
6108 {
6109         struct ext4_ext_path *path = NULL;
6110         struct ext4_extent *ex;
6111         ext4_lblk_t cur = 0, end;
6112         int j, ret = 0;
6113         struct ext4_map_blocks map;
6114
6115         if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA))
6116                 return 0;
6117
6118         /* Determin the size of the file first */
6119         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6120                                         EXT4_EX_NOCACHE);
6121         if (IS_ERR(path))
6122                 return PTR_ERR(path);
6123         ex = path[path->p_depth].p_ext;
6124         if (!ex) {
6125                 ext4_free_ext_path(path);
6126                 return 0;
6127         }
6128         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6129         ext4_free_ext_path(path);
6130
6131         cur = 0;
6132         while (cur < end) {
6133                 map.m_lblk = cur;
6134                 map.m_len = end - cur;
6135                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6136                 if (ret < 0)
6137                         break;
6138                 if (ret > 0) {
6139                         path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
6140                         if (!IS_ERR_OR_NULL(path)) {
6141                                 for (j = 0; j < path->p_depth; j++) {
6142
6143                                         ext4_mb_mark_bb(inode->i_sb,
6144                                                         path[j].p_block, 1, 0);
6145                                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6146                                                         0, path[j].p_block, 1, 1);
6147                                 }
6148                                 ext4_free_ext_path(path);
6149                         }
6150                         ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
6151                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6152                                         map.m_lblk, map.m_pblk, map.m_len, 1);
6153                 }
6154                 cur = cur + map.m_len;
6155         }
6156
6157         return 0;
6158 }