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_determine_hole - determine hole around given block
2233  * @inode:      inode we lookup in
2234  * @path:       path in extent tree to @lblk
2235  * @lblk:       pointer to logical block around which we want to determine hole
2236  *
2237  * Determine hole length (and start if easily possible) around given logical
2238  * block. We don't try too hard to find the beginning of the hole but @path
2239  * actually points to extent before @lblk, we provide it.
2240  *
2241  * The function returns the length of a hole starting at @lblk. We update @lblk
2242  * to the beginning of the hole if we managed to find it.
2243  */
2244 static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2245                                            struct ext4_ext_path *path,
2246                                            ext4_lblk_t *lblk)
2247 {
2248         int depth = ext_depth(inode);
2249         struct ext4_extent *ex;
2250         ext4_lblk_t len;
2251
2252         ex = path[depth].p_ext;
2253         if (ex == NULL) {
2254                 /* there is no extent yet, so gap is [0;-] */
2255                 *lblk = 0;
2256                 len = EXT_MAX_BLOCKS;
2257         } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2258                 len = le32_to_cpu(ex->ee_block) - *lblk;
2259         } else if (*lblk >= le32_to_cpu(ex->ee_block)
2260                         + ext4_ext_get_actual_len(ex)) {
2261                 ext4_lblk_t next;
2262
2263                 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2264                 next = ext4_ext_next_allocated_block(path);
2265                 BUG_ON(next == *lblk);
2266                 len = next - *lblk;
2267         } else {
2268                 BUG();
2269         }
2270         return len;
2271 }
2272
2273 /*
2274  * ext4_ext_put_gap_in_cache:
2275  * calculate boundaries of the gap that the requested block fits into
2276  * and cache this gap
2277  */
2278 static void
2279 ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2280                           ext4_lblk_t hole_len)
2281 {
2282         struct extent_status es;
2283
2284         ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
2285                                   hole_start + hole_len - 1, &es);
2286         if (es.es_len) {
2287                 /* There's delayed extent containing lblock? */
2288                 if (es.es_lblk <= hole_start)
2289                         return;
2290                 hole_len = min(es.es_lblk - hole_start, hole_len);
2291         }
2292         ext_debug(inode, " -> %u:%u\n", hole_start, hole_len);
2293         ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2294                               EXTENT_STATUS_HOLE);
2295 }
2296
2297 /*
2298  * ext4_ext_rm_idx:
2299  * removes index from the index block.
2300  */
2301 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2302                         struct ext4_ext_path *path, int depth)
2303 {
2304         int err;
2305         ext4_fsblk_t leaf;
2306
2307         /* free index block */
2308         depth--;
2309         path = path + depth;
2310         leaf = ext4_idx_pblock(path->p_idx);
2311         if (unlikely(path->p_hdr->eh_entries == 0)) {
2312                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2313                 return -EFSCORRUPTED;
2314         }
2315         err = ext4_ext_get_access(handle, inode, path);
2316         if (err)
2317                 return err;
2318
2319         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2320                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2321                 len *= sizeof(struct ext4_extent_idx);
2322                 memmove(path->p_idx, path->p_idx + 1, len);
2323         }
2324
2325         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2326         err = ext4_ext_dirty(handle, inode, path);
2327         if (err)
2328                 return err;
2329         ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
2330         trace_ext4_ext_rm_idx(inode, leaf);
2331
2332         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2333                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2334
2335         while (--depth >= 0) {
2336                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2337                         break;
2338                 path--;
2339                 err = ext4_ext_get_access(handle, inode, path);
2340                 if (err)
2341                         break;
2342                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2343                 err = ext4_ext_dirty(handle, inode, path);
2344                 if (err)
2345                         break;
2346         }
2347         return err;
2348 }
2349
2350 /*
2351  * ext4_ext_calc_credits_for_single_extent:
2352  * This routine returns max. credits that needed to insert an extent
2353  * to the extent tree.
2354  * When pass the actual path, the caller should calculate credits
2355  * under i_data_sem.
2356  */
2357 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2358                                                 struct ext4_ext_path *path)
2359 {
2360         if (path) {
2361                 int depth = ext_depth(inode);
2362                 int ret = 0;
2363
2364                 /* probably there is space in leaf? */
2365                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2366                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2367
2368                         /*
2369                          *  There are some space in the leaf tree, no
2370                          *  need to account for leaf block credit
2371                          *
2372                          *  bitmaps and block group descriptor blocks
2373                          *  and other metadata blocks still need to be
2374                          *  accounted.
2375                          */
2376                         /* 1 bitmap, 1 block group descriptor */
2377                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2378                         return ret;
2379                 }
2380         }
2381
2382         return ext4_chunk_trans_blocks(inode, nrblocks);
2383 }
2384
2385 /*
2386  * How many index/leaf blocks need to change/allocate to add @extents extents?
2387  *
2388  * If we add a single extent, then in the worse case, each tree level
2389  * index/leaf need to be changed in case of the tree split.
2390  *
2391  * If more extents are inserted, they could cause the whole tree split more
2392  * than once, but this is really rare.
2393  */
2394 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2395 {
2396         int index;
2397         int depth;
2398
2399         /* If we are converting the inline data, only one is needed here. */
2400         if (ext4_has_inline_data(inode))
2401                 return 1;
2402
2403         depth = ext_depth(inode);
2404
2405         if (extents <= 1)
2406                 index = depth * 2;
2407         else
2408                 index = depth * 3;
2409
2410         return index;
2411 }
2412
2413 static inline int get_default_free_blocks_flags(struct inode *inode)
2414 {
2415         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2416             ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2417                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2418         else if (ext4_should_journal_data(inode))
2419                 return EXT4_FREE_BLOCKS_FORGET;
2420         return 0;
2421 }
2422
2423 /*
2424  * ext4_rereserve_cluster - increment the reserved cluster count when
2425  *                          freeing a cluster with a pending reservation
2426  *
2427  * @inode - file containing the cluster
2428  * @lblk - logical block in cluster to be reserved
2429  *
2430  * Increments the reserved cluster count and adjusts quota in a bigalloc
2431  * file system when freeing a partial cluster containing at least one
2432  * delayed and unwritten block.  A partial cluster meeting that
2433  * requirement will have a pending reservation.  If so, the
2434  * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2435  * defer reserved and allocated space accounting to a subsequent call
2436  * to this function.
2437  */
2438 static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2439 {
2440         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2441         struct ext4_inode_info *ei = EXT4_I(inode);
2442
2443         dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2444
2445         spin_lock(&ei->i_block_reservation_lock);
2446         ei->i_reserved_data_blocks++;
2447         percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2448         spin_unlock(&ei->i_block_reservation_lock);
2449
2450         percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2451         ext4_remove_pending(inode, lblk);
2452 }
2453
2454 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2455                               struct ext4_extent *ex,
2456                               struct partial_cluster *partial,
2457                               ext4_lblk_t from, ext4_lblk_t to)
2458 {
2459         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2460         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2461         ext4_fsblk_t last_pblk, pblk;
2462         ext4_lblk_t num;
2463         int flags;
2464
2465         /* only extent tail removal is allowed */
2466         if (from < le32_to_cpu(ex->ee_block) ||
2467             to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2468                 ext4_error(sbi->s_sb,
2469                            "strange request: removal(2) %u-%u from %u:%u",
2470                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2471                 return 0;
2472         }
2473
2474 #ifdef EXTENTS_STATS
2475         spin_lock(&sbi->s_ext_stats_lock);
2476         sbi->s_ext_blocks += ee_len;
2477         sbi->s_ext_extents++;
2478         if (ee_len < sbi->s_ext_min)
2479                 sbi->s_ext_min = ee_len;
2480         if (ee_len > sbi->s_ext_max)
2481                 sbi->s_ext_max = ee_len;
2482         if (ext_depth(inode) > sbi->s_depth_max)
2483                 sbi->s_depth_max = ext_depth(inode);
2484         spin_unlock(&sbi->s_ext_stats_lock);
2485 #endif
2486
2487         trace_ext4_remove_blocks(inode, ex, from, to, partial);
2488
2489         /*
2490          * if we have a partial cluster, and it's different from the
2491          * cluster of the last block in the extent, we free it
2492          */
2493         last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2494
2495         if (partial->state != initial &&
2496             partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2497                 if (partial->state == tofree) {
2498                         flags = get_default_free_blocks_flags(inode);
2499                         if (ext4_is_pending(inode, partial->lblk))
2500                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2501                         ext4_free_blocks(handle, inode, NULL,
2502                                          EXT4_C2B(sbi, partial->pclu),
2503                                          sbi->s_cluster_ratio, flags);
2504                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2505                                 ext4_rereserve_cluster(inode, partial->lblk);
2506                 }
2507                 partial->state = initial;
2508         }
2509
2510         num = le32_to_cpu(ex->ee_block) + ee_len - from;
2511         pblk = ext4_ext_pblock(ex) + ee_len - num;
2512
2513         /*
2514          * We free the partial cluster at the end of the extent (if any),
2515          * unless the cluster is used by another extent (partial_cluster
2516          * state is nofree).  If a partial cluster exists here, it must be
2517          * shared with the last block in the extent.
2518          */
2519         flags = get_default_free_blocks_flags(inode);
2520
2521         /* partial, left end cluster aligned, right end unaligned */
2522         if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2523             (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2524             (partial->state != nofree)) {
2525                 if (ext4_is_pending(inode, to))
2526                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2527                 ext4_free_blocks(handle, inode, NULL,
2528                                  EXT4_PBLK_CMASK(sbi, last_pblk),
2529                                  sbi->s_cluster_ratio, flags);
2530                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2531                         ext4_rereserve_cluster(inode, to);
2532                 partial->state = initial;
2533                 flags = get_default_free_blocks_flags(inode);
2534         }
2535
2536         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2537
2538         /*
2539          * For bigalloc file systems, we never free a partial cluster
2540          * at the beginning of the extent.  Instead, we check to see if we
2541          * need to free it on a subsequent call to ext4_remove_blocks,
2542          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2543          */
2544         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2545         ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2546
2547         /* reset the partial cluster if we've freed past it */
2548         if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2549                 partial->state = initial;
2550
2551         /*
2552          * If we've freed the entire extent but the beginning is not left
2553          * cluster aligned and is not marked as ineligible for freeing we
2554          * record the partial cluster at the beginning of the extent.  It
2555          * wasn't freed by the preceding ext4_free_blocks() call, and we
2556          * need to look farther to the left to determine if it's to be freed
2557          * (not shared with another extent). Else, reset the partial
2558          * cluster - we're either  done freeing or the beginning of the
2559          * extent is left cluster aligned.
2560          */
2561         if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2562                 if (partial->state == initial) {
2563                         partial->pclu = EXT4_B2C(sbi, pblk);
2564                         partial->lblk = from;
2565                         partial->state = tofree;
2566                 }
2567         } else {
2568                 partial->state = initial;
2569         }
2570
2571         return 0;
2572 }
2573
2574 /*
2575  * ext4_ext_rm_leaf() Removes the extents associated with the
2576  * blocks appearing between "start" and "end".  Both "start"
2577  * and "end" must appear in the same extent or EIO is returned.
2578  *
2579  * @handle: The journal handle
2580  * @inode:  The files inode
2581  * @path:   The path to the leaf
2582  * @partial_cluster: The cluster which we'll have to free if all extents
2583  *                   has been released from it.  However, if this value is
2584  *                   negative, it's a cluster just to the right of the
2585  *                   punched region and it must not be freed.
2586  * @start:  The first block to remove
2587  * @end:   The last block to remove
2588  */
2589 static int
2590 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2591                  struct ext4_ext_path *path,
2592                  struct partial_cluster *partial,
2593                  ext4_lblk_t start, ext4_lblk_t end)
2594 {
2595         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2596         int err = 0, correct_index = 0;
2597         int depth = ext_depth(inode), credits, revoke_credits;
2598         struct ext4_extent_header *eh;
2599         ext4_lblk_t a, b;
2600         unsigned num;
2601         ext4_lblk_t ex_ee_block;
2602         unsigned short ex_ee_len;
2603         unsigned unwritten = 0;
2604         struct ext4_extent *ex;
2605         ext4_fsblk_t pblk;
2606
2607         /* the header must be checked already in ext4_ext_remove_space() */
2608         ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
2609         if (!path[depth].p_hdr)
2610                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2611         eh = path[depth].p_hdr;
2612         if (unlikely(path[depth].p_hdr == NULL)) {
2613                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2614                 return -EFSCORRUPTED;
2615         }
2616         /* find where to start removing */
2617         ex = path[depth].p_ext;
2618         if (!ex)
2619                 ex = EXT_LAST_EXTENT(eh);
2620
2621         ex_ee_block = le32_to_cpu(ex->ee_block);
2622         ex_ee_len = ext4_ext_get_actual_len(ex);
2623
2624         trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2625
2626         while (ex >= EXT_FIRST_EXTENT(eh) &&
2627                         ex_ee_block + ex_ee_len > start) {
2628
2629                 if (ext4_ext_is_unwritten(ex))
2630                         unwritten = 1;
2631                 else
2632                         unwritten = 0;
2633
2634                 ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
2635                           unwritten, ex_ee_len);
2636                 path[depth].p_ext = ex;
2637
2638                 a = max(ex_ee_block, start);
2639                 b = min(ex_ee_block + ex_ee_len - 1, end);
2640
2641                 ext_debug(inode, "  border %u:%u\n", a, b);
2642
2643                 /* If this extent is beyond the end of the hole, skip it */
2644                 if (end < ex_ee_block) {
2645                         /*
2646                          * We're going to skip this extent and move to another,
2647                          * so note that its first cluster is in use to avoid
2648                          * freeing it when removing blocks.  Eventually, the
2649                          * right edge of the truncated/punched region will
2650                          * be just to the left.
2651                          */
2652                         if (sbi->s_cluster_ratio > 1) {
2653                                 pblk = ext4_ext_pblock(ex);
2654                                 partial->pclu = EXT4_B2C(sbi, pblk);
2655                                 partial->state = nofree;
2656                         }
2657                         ex--;
2658                         ex_ee_block = le32_to_cpu(ex->ee_block);
2659                         ex_ee_len = ext4_ext_get_actual_len(ex);
2660                         continue;
2661                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2662                         EXT4_ERROR_INODE(inode,
2663                                          "can not handle truncate %u:%u "
2664                                          "on extent %u:%u",
2665                                          start, end, ex_ee_block,
2666                                          ex_ee_block + ex_ee_len - 1);
2667                         err = -EFSCORRUPTED;
2668                         goto out;
2669                 } else if (a != ex_ee_block) {
2670                         /* remove tail of the extent */
2671                         num = a - ex_ee_block;
2672                 } else {
2673                         /* remove whole extent: excellent! */
2674                         num = 0;
2675                 }
2676                 /*
2677                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2678                  * descriptor) for each block group; assume two block
2679                  * groups plus ex_ee_len/blocks_per_block_group for
2680                  * the worst case
2681                  */
2682                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2683                 if (ex == EXT_FIRST_EXTENT(eh)) {
2684                         correct_index = 1;
2685                         credits += (ext_depth(inode)) + 1;
2686                 }
2687                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2688                 /*
2689                  * We may end up freeing some index blocks and data from the
2690                  * punched range. Note that partial clusters are accounted for
2691                  * by ext4_free_data_revoke_credits().
2692                  */
2693                 revoke_credits =
2694                         ext4_free_metadata_revoke_credits(inode->i_sb,
2695                                                           ext_depth(inode)) +
2696                         ext4_free_data_revoke_credits(inode, b - a + 1);
2697
2698                 err = ext4_datasem_ensure_credits(handle, inode, credits,
2699                                                   credits, revoke_credits);
2700                 if (err) {
2701                         if (err > 0)
2702                                 err = -EAGAIN;
2703                         goto out;
2704                 }
2705
2706                 err = ext4_ext_get_access(handle, inode, path + depth);
2707                 if (err)
2708                         goto out;
2709
2710                 err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2711                 if (err)
2712                         goto out;
2713
2714                 if (num == 0)
2715                         /* this extent is removed; mark slot entirely unused */
2716                         ext4_ext_store_pblock(ex, 0);
2717
2718                 ex->ee_len = cpu_to_le16(num);
2719                 /*
2720                  * Do not mark unwritten if all the blocks in the
2721                  * extent have been removed.
2722                  */
2723                 if (unwritten && num)
2724                         ext4_ext_mark_unwritten(ex);
2725                 /*
2726                  * If the extent was completely released,
2727                  * we need to remove it from the leaf
2728                  */
2729                 if (num == 0) {
2730                         if (end != EXT_MAX_BLOCKS - 1) {
2731                                 /*
2732                                  * For hole punching, we need to scoot all the
2733                                  * extents up when an extent is removed so that
2734                                  * we dont have blank extents in the middle
2735                                  */
2736                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2737                                         sizeof(struct ext4_extent));
2738
2739                                 /* Now get rid of the one at the end */
2740                                 memset(EXT_LAST_EXTENT(eh), 0,
2741                                         sizeof(struct ext4_extent));
2742                         }
2743                         le16_add_cpu(&eh->eh_entries, -1);
2744                 }
2745
2746                 err = ext4_ext_dirty(handle, inode, path + depth);
2747                 if (err)
2748                         goto out;
2749
2750                 ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
2751                                 ext4_ext_pblock(ex));
2752                 ex--;
2753                 ex_ee_block = le32_to_cpu(ex->ee_block);
2754                 ex_ee_len = ext4_ext_get_actual_len(ex);
2755         }
2756
2757         if (correct_index && eh->eh_entries)
2758                 err = ext4_ext_correct_indexes(handle, inode, path);
2759
2760         /*
2761          * If there's a partial cluster and at least one extent remains in
2762          * the leaf, free the partial cluster if it isn't shared with the
2763          * current extent.  If it is shared with the current extent
2764          * we reset the partial cluster because we've reached the start of the
2765          * truncated/punched region and we're done removing blocks.
2766          */
2767         if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2768                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2769                 if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2770                         int flags = get_default_free_blocks_flags(inode);
2771
2772                         if (ext4_is_pending(inode, partial->lblk))
2773                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2774                         ext4_free_blocks(handle, inode, NULL,
2775                                          EXT4_C2B(sbi, partial->pclu),
2776                                          sbi->s_cluster_ratio, flags);
2777                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2778                                 ext4_rereserve_cluster(inode, partial->lblk);
2779                 }
2780                 partial->state = initial;
2781         }
2782
2783         /* if this leaf is free, then we should
2784          * remove it from index block above */
2785         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2786                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2787
2788 out:
2789         return err;
2790 }
2791
2792 /*
2793  * ext4_ext_more_to_rm:
2794  * returns 1 if current index has to be freed (even partial)
2795  */
2796 static int
2797 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2798 {
2799         BUG_ON(path->p_idx == NULL);
2800
2801         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2802                 return 0;
2803
2804         /*
2805          * if truncate on deeper level happened, it wasn't partial,
2806          * so we have to consider current index for truncation
2807          */
2808         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2809                 return 0;
2810         return 1;
2811 }
2812
2813 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2814                           ext4_lblk_t end)
2815 {
2816         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2817         int depth = ext_depth(inode);
2818         struct ext4_ext_path *path = NULL;
2819         struct partial_cluster partial;
2820         handle_t *handle;
2821         int i = 0, err = 0;
2822
2823         partial.pclu = 0;
2824         partial.lblk = 0;
2825         partial.state = initial;
2826
2827         ext_debug(inode, "truncate since %u to %u\n", start, end);
2828
2829         /* probably first extent we're gonna free will be last in block */
2830         handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2831                         depth + 1,
2832                         ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2833         if (IS_ERR(handle))
2834                 return PTR_ERR(handle);
2835
2836 again:
2837         trace_ext4_ext_remove_space(inode, start, end, depth);
2838
2839         /*
2840          * Check if we are removing extents inside the extent tree. If that
2841          * is the case, we are going to punch a hole inside the extent tree
2842          * so we have to check whether we need to split the extent covering
2843          * the last block to remove so we can easily remove the part of it
2844          * in ext4_ext_rm_leaf().
2845          */
2846         if (end < EXT_MAX_BLOCKS - 1) {
2847                 struct ext4_extent *ex;
2848                 ext4_lblk_t ee_block, ex_end, lblk;
2849                 ext4_fsblk_t pblk;
2850
2851                 /* find extent for or closest extent to this block */
2852                 path = ext4_find_extent(inode, end, NULL,
2853                                         EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
2854                 if (IS_ERR(path)) {
2855                         ext4_journal_stop(handle);
2856                         return PTR_ERR(path);
2857                 }
2858                 depth = ext_depth(inode);
2859                 /* Leaf not may not exist only if inode has no blocks at all */
2860                 ex = path[depth].p_ext;
2861                 if (!ex) {
2862                         if (depth) {
2863                                 EXT4_ERROR_INODE(inode,
2864                                                  "path[%d].p_hdr == NULL",
2865                                                  depth);
2866                                 err = -EFSCORRUPTED;
2867                         }
2868                         goto out;
2869                 }
2870
2871                 ee_block = le32_to_cpu(ex->ee_block);
2872                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2873
2874                 /*
2875                  * See if the last block is inside the extent, if so split
2876                  * the extent at 'end' block so we can easily remove the
2877                  * tail of the first part of the split extent in
2878                  * ext4_ext_rm_leaf().
2879                  */
2880                 if (end >= ee_block && end < ex_end) {
2881
2882                         /*
2883                          * If we're going to split the extent, note that
2884                          * the cluster containing the block after 'end' is
2885                          * in use to avoid freeing it when removing blocks.
2886                          */
2887                         if (sbi->s_cluster_ratio > 1) {
2888                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
2889                                 partial.pclu = EXT4_B2C(sbi, pblk);
2890                                 partial.state = nofree;
2891                         }
2892
2893                         /*
2894                          * Split the extent in two so that 'end' is the last
2895                          * block in the first new extent. Also we should not
2896                          * fail removing space due to ENOSPC so try to use
2897                          * reserved block if that happens.
2898                          */
2899                         err = ext4_force_split_extent_at(handle, inode, &path,
2900                                                          end + 1, 1);
2901                         if (err < 0)
2902                                 goto out;
2903
2904                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
2905                            partial.state == initial) {
2906                         /*
2907                          * If we're punching, there's an extent to the right.
2908                          * If the partial cluster hasn't been set, set it to
2909                          * that extent's first cluster and its state to nofree
2910                          * so it won't be freed should it contain blocks to be
2911                          * removed. If it's already set (tofree/nofree), we're
2912                          * retrying and keep the original partial cluster info
2913                          * so a cluster marked tofree as a result of earlier
2914                          * extent removal is not lost.
2915                          */
2916                         lblk = ex_end + 1;
2917                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2918                                                     NULL);
2919                         if (err < 0)
2920                                 goto out;
2921                         if (pblk) {
2922                                 partial.pclu = EXT4_B2C(sbi, pblk);
2923                                 partial.state = nofree;
2924                         }
2925                 }
2926         }
2927         /*
2928          * We start scanning from right side, freeing all the blocks
2929          * after i_size and walking into the tree depth-wise.
2930          */
2931         depth = ext_depth(inode);
2932         if (path) {
2933                 int k = i = depth;
2934                 while (--k > 0)
2935                         path[k].p_block =
2936                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2937         } else {
2938                 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
2939                                GFP_NOFS | __GFP_NOFAIL);
2940                 if (path == NULL) {
2941                         ext4_journal_stop(handle);
2942                         return -ENOMEM;
2943                 }
2944                 path[0].p_maxdepth = path[0].p_depth = depth;
2945                 path[0].p_hdr = ext_inode_hdr(inode);
2946                 i = 0;
2947
2948                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2949                         err = -EFSCORRUPTED;
2950                         goto out;
2951                 }
2952         }
2953         err = 0;
2954
2955         while (i >= 0 && err == 0) {
2956                 if (i == depth) {
2957                         /* this is leaf block */
2958                         err = ext4_ext_rm_leaf(handle, inode, path,
2959                                                &partial, start, end);
2960                         /* root level has p_bh == NULL, brelse() eats this */
2961                         brelse(path[i].p_bh);
2962                         path[i].p_bh = NULL;
2963                         i--;
2964                         continue;
2965                 }
2966
2967                 /* this is index block */
2968                 if (!path[i].p_hdr) {
2969                         ext_debug(inode, "initialize header\n");
2970                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2971                 }
2972
2973                 if (!path[i].p_idx) {
2974                         /* this level hasn't been touched yet */
2975                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2976                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2977                         ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
2978                                   path[i].p_hdr,
2979                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2980                 } else {
2981                         /* we were already here, see at next index */
2982                         path[i].p_idx--;
2983                 }
2984
2985                 ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
2986                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2987                                 path[i].p_idx);
2988                 if (ext4_ext_more_to_rm(path + i)) {
2989                         struct buffer_head *bh;
2990                         /* go to the next level */
2991                         ext_debug(inode, "move to level %d (block %llu)\n",
2992                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2993                         memset(path + i + 1, 0, sizeof(*path));
2994                         bh = read_extent_tree_block(inode, path[i].p_idx,
2995                                                     depth - i - 1,
2996                                                     EXT4_EX_NOCACHE);
2997                         if (IS_ERR(bh)) {
2998                                 /* should we reset i_size? */
2999                                 err = PTR_ERR(bh);
3000                                 break;
3001                         }
3002                         /* Yield here to deal with large extent trees.
3003                          * Should be a no-op if we did IO above. */
3004                         cond_resched();
3005                         if (WARN_ON(i + 1 > depth)) {
3006                                 err = -EFSCORRUPTED;
3007                                 break;
3008                         }
3009                         path[i + 1].p_bh = bh;
3010
3011                         /* save actual number of indexes since this
3012                          * number is changed at the next iteration */
3013                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3014                         i++;
3015                 } else {
3016                         /* we finished processing this index, go up */
3017                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3018                                 /* index is empty, remove it;
3019                                  * handle must be already prepared by the
3020                                  * truncatei_leaf() */
3021                                 err = ext4_ext_rm_idx(handle, inode, path, i);
3022                         }
3023                         /* root level has p_bh == NULL, brelse() eats this */
3024                         brelse(path[i].p_bh);
3025                         path[i].p_bh = NULL;
3026                         i--;
3027                         ext_debug(inode, "return to level %d\n", i);
3028                 }
3029         }
3030
3031         trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3032                                          path->p_hdr->eh_entries);
3033
3034         /*
3035          * if there's a partial cluster and we have removed the first extent
3036          * in the file, then we also free the partial cluster, if any
3037          */
3038         if (partial.state == tofree && err == 0) {
3039                 int flags = get_default_free_blocks_flags(inode);
3040
3041                 if (ext4_is_pending(inode, partial.lblk))
3042                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3043                 ext4_free_blocks(handle, inode, NULL,
3044                                  EXT4_C2B(sbi, partial.pclu),
3045                                  sbi->s_cluster_ratio, flags);
3046                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3047                         ext4_rereserve_cluster(inode, partial.lblk);
3048                 partial.state = initial;
3049         }
3050
3051         /* TODO: flexible tree reduction should be here */
3052         if (path->p_hdr->eh_entries == 0) {
3053                 /*
3054                  * truncate to zero freed all the tree,
3055                  * so we need to correct eh_depth
3056                  */
3057                 err = ext4_ext_get_access(handle, inode, path);
3058                 if (err == 0) {
3059                         ext_inode_hdr(inode)->eh_depth = 0;
3060                         ext_inode_hdr(inode)->eh_max =
3061                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3062                         err = ext4_ext_dirty(handle, inode, path);
3063                 }
3064         }
3065 out:
3066         ext4_free_ext_path(path);
3067         path = NULL;
3068         if (err == -EAGAIN)
3069                 goto again;
3070         ext4_journal_stop(handle);
3071
3072         return err;
3073 }
3074
3075 /*
3076  * called at mount time
3077  */
3078 void ext4_ext_init(struct super_block *sb)
3079 {
3080         /*
3081          * possible initialization would be here
3082          */
3083
3084         if (ext4_has_feature_extents(sb)) {
3085 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3086                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3087 #ifdef AGGRESSIVE_TEST
3088                        ", aggressive tests"
3089 #endif
3090 #ifdef CHECK_BINSEARCH
3091                        ", check binsearch"
3092 #endif
3093 #ifdef EXTENTS_STATS
3094                        ", stats"
3095 #endif
3096                        "\n");
3097 #endif
3098 #ifdef EXTENTS_STATS
3099                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3100                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3101                 EXT4_SB(sb)->s_ext_max = 0;
3102 #endif
3103         }
3104 }
3105
3106 /*
3107  * called at umount time
3108  */
3109 void ext4_ext_release(struct super_block *sb)
3110 {
3111         if (!ext4_has_feature_extents(sb))
3112                 return;
3113
3114 #ifdef EXTENTS_STATS
3115         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3116                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3117                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3118                         sbi->s_ext_blocks, sbi->s_ext_extents,
3119                         sbi->s_ext_blocks / sbi->s_ext_extents);
3120                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3121                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3122         }
3123 #endif
3124 }
3125
3126 static void ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3127 {
3128         ext4_lblk_t  ee_block;
3129         ext4_fsblk_t ee_pblock;
3130         unsigned int ee_len;
3131
3132         ee_block  = le32_to_cpu(ex->ee_block);
3133         ee_len    = ext4_ext_get_actual_len(ex);
3134         ee_pblock = ext4_ext_pblock(ex);
3135
3136         if (ee_len == 0)
3137                 return;
3138
3139         ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3140                               EXTENT_STATUS_WRITTEN);
3141 }
3142
3143 /* FIXME!! we need to try to merge to left or right after zero-out  */
3144 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3145 {
3146         ext4_fsblk_t ee_pblock;
3147         unsigned int ee_len;
3148
3149         ee_len    = ext4_ext_get_actual_len(ex);
3150         ee_pblock = ext4_ext_pblock(ex);
3151         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3152                                   ee_len);
3153 }
3154
3155 /*
3156  * ext4_split_extent_at() splits an extent at given block.
3157  *
3158  * @handle: the journal handle
3159  * @inode: the file inode
3160  * @path: the path to the extent
3161  * @split: the logical block where the extent is splitted.
3162  * @split_flags: indicates if the extent could be zeroout if split fails, and
3163  *               the states(init or unwritten) of new extents.
3164  * @flags: flags used to insert new extent to extent tree.
3165  *
3166  *
3167  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3168  * of which are determined by split_flag.
3169  *
3170  * There are two cases:
3171  *  a> the extent are splitted into two extent.
3172  *  b> split is not needed, and just mark the extent.
3173  *
3174  * return 0 on success.
3175  */
3176 static int ext4_split_extent_at(handle_t *handle,
3177                              struct inode *inode,
3178                              struct ext4_ext_path **ppath,
3179                              ext4_lblk_t split,
3180                              int split_flag,
3181                              int flags)
3182 {
3183         struct ext4_ext_path *path = *ppath;
3184         ext4_fsblk_t newblock;
3185         ext4_lblk_t ee_block;
3186         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3187         struct ext4_extent *ex2 = NULL;
3188         unsigned int ee_len, depth;
3189         int err = 0;
3190
3191         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3192                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3193
3194         ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
3195
3196         ext4_ext_show_leaf(inode, path);
3197
3198         depth = ext_depth(inode);
3199         ex = path[depth].p_ext;
3200         ee_block = le32_to_cpu(ex->ee_block);
3201         ee_len = ext4_ext_get_actual_len(ex);
3202         newblock = split - ee_block + ext4_ext_pblock(ex);
3203
3204         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3205         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3206                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3207                              EXT4_EXT_MARK_UNWRIT1 |
3208                              EXT4_EXT_MARK_UNWRIT2));
3209
3210         err = ext4_ext_get_access(handle, inode, path + depth);
3211         if (err)
3212                 goto out;
3213
3214         if (split == ee_block) {
3215                 /*
3216                  * case b: block @split is the block that the extent begins with
3217                  * then we just change the state of the extent, and splitting
3218                  * is not needed.
3219                  */
3220                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3221                         ext4_ext_mark_unwritten(ex);
3222                 else
3223                         ext4_ext_mark_initialized(ex);
3224
3225                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3226                         ext4_ext_try_to_merge(handle, inode, path, ex);
3227
3228                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3229                 goto out;
3230         }
3231
3232         /* case a */
3233         memcpy(&orig_ex, ex, sizeof(orig_ex));
3234         ex->ee_len = cpu_to_le16(split - ee_block);
3235         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3236                 ext4_ext_mark_unwritten(ex);
3237
3238         /*
3239          * path may lead to new leaf, not to original leaf any more
3240          * after ext4_ext_insert_extent() returns,
3241          */
3242         err = ext4_ext_dirty(handle, inode, path + depth);
3243         if (err)
3244                 goto fix_extent_len;
3245
3246         ex2 = &newex;
3247         ex2->ee_block = cpu_to_le32(split);
3248         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3249         ext4_ext_store_pblock(ex2, newblock);
3250         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3251                 ext4_ext_mark_unwritten(ex2);
3252
3253         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3254         if (err != -ENOSPC && err != -EDQUOT && err != -ENOMEM)
3255                 goto out;
3256
3257         if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
3258                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3259                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3260                                 err = ext4_ext_zeroout(inode, ex2);
3261                                 zero_ex.ee_block = ex2->ee_block;
3262                                 zero_ex.ee_len = cpu_to_le16(
3263                                                 ext4_ext_get_actual_len(ex2));
3264                                 ext4_ext_store_pblock(&zero_ex,
3265                                                       ext4_ext_pblock(ex2));
3266                         } else {
3267                                 err = ext4_ext_zeroout(inode, ex);
3268                                 zero_ex.ee_block = ex->ee_block;
3269                                 zero_ex.ee_len = cpu_to_le16(
3270                                                 ext4_ext_get_actual_len(ex));
3271                                 ext4_ext_store_pblock(&zero_ex,
3272                                                       ext4_ext_pblock(ex));
3273                         }
3274                 } else {
3275                         err = ext4_ext_zeroout(inode, &orig_ex);
3276                         zero_ex.ee_block = orig_ex.ee_block;
3277                         zero_ex.ee_len = cpu_to_le16(
3278                                                 ext4_ext_get_actual_len(&orig_ex));
3279                         ext4_ext_store_pblock(&zero_ex,
3280                                               ext4_ext_pblock(&orig_ex));
3281                 }
3282
3283                 if (!err) {
3284                         /* update the extent length and mark as initialized */
3285                         ex->ee_len = cpu_to_le16(ee_len);
3286                         ext4_ext_try_to_merge(handle, inode, path, ex);
3287                         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3288                         if (!err)
3289                                 /* update extent status tree */
3290                                 ext4_zeroout_es(inode, &zero_ex);
3291                         /* If we failed at this point, we don't know in which
3292                          * state the extent tree exactly is so don't try to fix
3293                          * length of the original extent as it may do even more
3294                          * damage.
3295                          */
3296                         goto out;
3297                 }
3298         }
3299
3300 fix_extent_len:
3301         ex->ee_len = orig_ex.ee_len;
3302         /*
3303          * Ignore ext4_ext_dirty return value since we are already in error path
3304          * and err is a non-zero error code.
3305          */
3306         ext4_ext_dirty(handle, inode, path + path->p_depth);
3307         return err;
3308 out:
3309         ext4_ext_show_leaf(inode, path);
3310         return err;
3311 }
3312
3313 /*
3314  * ext4_split_extents() splits an extent and mark extent which is covered
3315  * by @map as split_flags indicates
3316  *
3317  * It may result in splitting the extent into multiple extents (up to three)
3318  * There are three possibilities:
3319  *   a> There is no split required
3320  *   b> Splits in two extents: Split is happening at either end of the extent
3321  *   c> Splits in three extents: Somone is splitting in middle of the extent
3322  *
3323  */
3324 static int ext4_split_extent(handle_t *handle,
3325                               struct inode *inode,
3326                               struct ext4_ext_path **ppath,
3327                               struct ext4_map_blocks *map,
3328                               int split_flag,
3329                               int flags)
3330 {
3331         struct ext4_ext_path *path = *ppath;
3332         ext4_lblk_t ee_block;
3333         struct ext4_extent *ex;
3334         unsigned int ee_len, depth;
3335         int err = 0;
3336         int unwritten;
3337         int split_flag1, flags1;
3338         int allocated = map->m_len;
3339
3340         depth = ext_depth(inode);
3341         ex = path[depth].p_ext;
3342         ee_block = le32_to_cpu(ex->ee_block);
3343         ee_len = ext4_ext_get_actual_len(ex);
3344         unwritten = ext4_ext_is_unwritten(ex);
3345
3346         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3347                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3348                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3349                 if (unwritten)
3350                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3351                                        EXT4_EXT_MARK_UNWRIT2;
3352                 if (split_flag & EXT4_EXT_DATA_VALID2)
3353                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3354                 err = ext4_split_extent_at(handle, inode, ppath,
3355                                 map->m_lblk + map->m_len, split_flag1, flags1);
3356                 if (err)
3357                         goto out;
3358         } else {
3359                 allocated = ee_len - (map->m_lblk - ee_block);
3360         }
3361         /*
3362          * Update path is required because previous ext4_split_extent_at() may
3363          * result in split of original leaf or extent zeroout.
3364          */
3365         path = ext4_find_extent(inode, map->m_lblk, ppath, flags);
3366         if (IS_ERR(path))
3367                 return PTR_ERR(path);
3368         depth = ext_depth(inode);
3369         ex = path[depth].p_ext;
3370         if (!ex) {
3371                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3372                                  (unsigned long) map->m_lblk);
3373                 return -EFSCORRUPTED;
3374         }
3375         unwritten = ext4_ext_is_unwritten(ex);
3376
3377         if (map->m_lblk >= ee_block) {
3378                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3379                 if (unwritten) {
3380                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3381                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3382                                                      EXT4_EXT_MARK_UNWRIT2);
3383                 }
3384                 err = ext4_split_extent_at(handle, inode, ppath,
3385                                 map->m_lblk, split_flag1, flags);
3386                 if (err)
3387                         goto out;
3388         }
3389
3390         ext4_ext_show_leaf(inode, path);
3391 out:
3392         return err ? err : allocated;
3393 }
3394
3395 /*
3396  * This function is called by ext4_ext_map_blocks() if someone tries to write
3397  * to an unwritten extent. It may result in splitting the unwritten
3398  * extent into multiple extents (up to three - one initialized and two
3399  * unwritten).
3400  * There are three possibilities:
3401  *   a> There is no split required: Entire extent should be initialized
3402  *   b> Splits in two extents: Write is happening at either end of the extent
3403  *   c> Splits in three extents: Somone is writing in middle of the extent
3404  *
3405  * Pre-conditions:
3406  *  - The extent pointed to by 'path' is unwritten.
3407  *  - The extent pointed to by 'path' contains a superset
3408  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3409  *
3410  * Post-conditions on success:
3411  *  - the returned value is the number of blocks beyond map->l_lblk
3412  *    that are allocated and initialized.
3413  *    It is guaranteed to be >= map->m_len.
3414  */
3415 static int ext4_ext_convert_to_initialized(handle_t *handle,
3416                                            struct inode *inode,
3417                                            struct ext4_map_blocks *map,
3418                                            struct ext4_ext_path **ppath,
3419                                            int flags)
3420 {
3421         struct ext4_ext_path *path = *ppath;
3422         struct ext4_sb_info *sbi;
3423         struct ext4_extent_header *eh;
3424         struct ext4_map_blocks split_map;
3425         struct ext4_extent zero_ex1, zero_ex2;
3426         struct ext4_extent *ex, *abut_ex;
3427         ext4_lblk_t ee_block, eof_block;
3428         unsigned int ee_len, depth, map_len = map->m_len;
3429         int allocated = 0, max_zeroout = 0;
3430         int err = 0;
3431         int split_flag = EXT4_EXT_DATA_VALID2;
3432
3433         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3434                   (unsigned long long)map->m_lblk, map_len);
3435
3436         sbi = EXT4_SB(inode->i_sb);
3437         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3438                         >> inode->i_sb->s_blocksize_bits;
3439         if (eof_block < map->m_lblk + map_len)
3440                 eof_block = map->m_lblk + map_len;
3441
3442         depth = ext_depth(inode);
3443         eh = path[depth].p_hdr;
3444         ex = path[depth].p_ext;
3445         ee_block = le32_to_cpu(ex->ee_block);
3446         ee_len = ext4_ext_get_actual_len(ex);
3447         zero_ex1.ee_len = 0;
3448         zero_ex2.ee_len = 0;
3449
3450         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3451
3452         /* Pre-conditions */
3453         BUG_ON(!ext4_ext_is_unwritten(ex));
3454         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3455
3456         /*
3457          * Attempt to transfer newly initialized blocks from the currently
3458          * unwritten extent to its neighbor. This is much cheaper
3459          * than an insertion followed by a merge as those involve costly
3460          * memmove() calls. Transferring to the left is the common case in
3461          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3462          * followed by append writes.
3463          *
3464          * Limitations of the current logic:
3465          *  - L1: we do not deal with writes covering the whole extent.
3466          *    This would require removing the extent if the transfer
3467          *    is possible.
3468          *  - L2: we only attempt to merge with an extent stored in the
3469          *    same extent tree node.
3470          */
3471         if ((map->m_lblk == ee_block) &&
3472                 /* See if we can merge left */
3473                 (map_len < ee_len) &&           /*L1*/
3474                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3475                 ext4_lblk_t prev_lblk;
3476                 ext4_fsblk_t prev_pblk, ee_pblk;
3477                 unsigned int prev_len;
3478
3479                 abut_ex = ex - 1;
3480                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3481                 prev_len = ext4_ext_get_actual_len(abut_ex);
3482                 prev_pblk = ext4_ext_pblock(abut_ex);
3483                 ee_pblk = ext4_ext_pblock(ex);
3484
3485                 /*
3486                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3487                  * upon those conditions:
3488                  * - C1: abut_ex is initialized,
3489                  * - C2: abut_ex is logically abutting ex,
3490                  * - C3: abut_ex is physically abutting ex,
3491                  * - C4: abut_ex can receive the additional blocks without
3492                  *   overflowing the (initialized) length limit.
3493                  */
3494                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3495                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3496                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3497                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3498                         err = ext4_ext_get_access(handle, inode, path + depth);
3499                         if (err)
3500                                 goto out;
3501
3502                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3503                                 map, ex, abut_ex);
3504
3505                         /* Shift the start of ex by 'map_len' blocks */
3506                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3507                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3508                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3509                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3510
3511                         /* Extend abut_ex by 'map_len' blocks */
3512                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3513
3514                         /* Result: number of initialized blocks past m_lblk */
3515                         allocated = map_len;
3516                 }
3517         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3518                    (map_len < ee_len) &&        /*L1*/
3519                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3520                 /* See if we can merge right */
3521                 ext4_lblk_t next_lblk;
3522                 ext4_fsblk_t next_pblk, ee_pblk;
3523                 unsigned int next_len;
3524
3525                 abut_ex = ex + 1;
3526                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3527                 next_len = ext4_ext_get_actual_len(abut_ex);
3528                 next_pblk = ext4_ext_pblock(abut_ex);
3529                 ee_pblk = ext4_ext_pblock(ex);
3530
3531                 /*
3532                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3533                  * upon those conditions:
3534                  * - C1: abut_ex is initialized,
3535                  * - C2: abut_ex is logically abutting ex,
3536                  * - C3: abut_ex is physically abutting ex,
3537                  * - C4: abut_ex can receive the additional blocks without
3538                  *   overflowing the (initialized) length limit.
3539                  */
3540                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3541                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3542                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3543                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3544                         err = ext4_ext_get_access(handle, inode, path + depth);
3545                         if (err)
3546                                 goto out;
3547
3548                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3549                                 map, ex, abut_ex);
3550
3551                         /* Shift the start of abut_ex by 'map_len' blocks */
3552                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3553                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3554                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3555                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3556
3557                         /* Extend abut_ex by 'map_len' blocks */
3558                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3559
3560                         /* Result: number of initialized blocks past m_lblk */
3561                         allocated = map_len;
3562                 }
3563         }
3564         if (allocated) {
3565                 /* Mark the block containing both extents as dirty */
3566                 err = ext4_ext_dirty(handle, inode, path + depth);
3567
3568                 /* Update path to point to the right extent */
3569                 path[depth].p_ext = abut_ex;
3570                 goto out;
3571         } else
3572                 allocated = ee_len - (map->m_lblk - ee_block);
3573
3574         WARN_ON(map->m_lblk < ee_block);
3575         /*
3576          * It is safe to convert extent to initialized via explicit
3577          * zeroout only if extent is fully inside i_size or new_size.
3578          */
3579         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3580
3581         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3582                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3583                         (inode->i_sb->s_blocksize_bits - 10);
3584
3585         /*
3586          * five cases:
3587          * 1. split the extent into three extents.
3588          * 2. split the extent into two extents, zeroout the head of the first
3589          *    extent.
3590          * 3. split the extent into two extents, zeroout the tail of the second
3591          *    extent.
3592          * 4. split the extent into two extents with out zeroout.
3593          * 5. no splitting needed, just possibly zeroout the head and / or the
3594          *    tail of the extent.
3595          */
3596         split_map.m_lblk = map->m_lblk;
3597         split_map.m_len = map->m_len;
3598
3599         if (max_zeroout && (allocated > split_map.m_len)) {
3600                 if (allocated <= max_zeroout) {
3601                         /* case 3 or 5 */
3602                         zero_ex1.ee_block =
3603                                  cpu_to_le32(split_map.m_lblk +
3604                                              split_map.m_len);
3605                         zero_ex1.ee_len =
3606                                 cpu_to_le16(allocated - split_map.m_len);
3607                         ext4_ext_store_pblock(&zero_ex1,
3608                                 ext4_ext_pblock(ex) + split_map.m_lblk +
3609                                 split_map.m_len - ee_block);
3610                         err = ext4_ext_zeroout(inode, &zero_ex1);
3611                         if (err)
3612                                 goto fallback;
3613                         split_map.m_len = allocated;
3614                 }
3615                 if (split_map.m_lblk - ee_block + split_map.m_len <
3616                                                                 max_zeroout) {
3617                         /* case 2 or 5 */
3618                         if (split_map.m_lblk != ee_block) {
3619                                 zero_ex2.ee_block = ex->ee_block;
3620                                 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3621                                                         ee_block);
3622                                 ext4_ext_store_pblock(&zero_ex2,
3623                                                       ext4_ext_pblock(ex));
3624                                 err = ext4_ext_zeroout(inode, &zero_ex2);
3625                                 if (err)
3626                                         goto fallback;
3627                         }
3628
3629                         split_map.m_len += split_map.m_lblk - ee_block;
3630                         split_map.m_lblk = ee_block;
3631                         allocated = map->m_len;
3632                 }
3633         }
3634
3635 fallback:
3636         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3637                                 flags);
3638         if (err > 0)
3639                 err = 0;
3640 out:
3641         /* If we have gotten a failure, don't zero out status tree */
3642         if (!err) {
3643                 ext4_zeroout_es(inode, &zero_ex1);
3644                 ext4_zeroout_es(inode, &zero_ex2);
3645         }
3646         return err ? err : allocated;
3647 }
3648
3649 /*
3650  * This function is called by ext4_ext_map_blocks() from
3651  * ext4_get_blocks_dio_write() when DIO to write
3652  * to an unwritten extent.
3653  *
3654  * Writing to an unwritten extent may result in splitting the unwritten
3655  * extent into multiple initialized/unwritten extents (up to three)
3656  * There are three possibilities:
3657  *   a> There is no split required: Entire extent should be unwritten
3658  *   b> Splits in two extents: Write is happening at either end of the extent
3659  *   c> Splits in three extents: Somone is writing in middle of the extent
3660  *
3661  * This works the same way in the case of initialized -> unwritten conversion.
3662  *
3663  * One of more index blocks maybe needed if the extent tree grow after
3664  * the unwritten extent split. To prevent ENOSPC occur at the IO
3665  * complete, we need to split the unwritten extent before DIO submit
3666  * the IO. The unwritten extent called at this time will be split
3667  * into three unwritten extent(at most). After IO complete, the part
3668  * being filled will be convert to initialized by the end_io callback function
3669  * via ext4_convert_unwritten_extents().
3670  *
3671  * Returns the size of unwritten extent to be written on success.
3672  */
3673 static int ext4_split_convert_extents(handle_t *handle,
3674                                         struct inode *inode,
3675                                         struct ext4_map_blocks *map,
3676                                         struct ext4_ext_path **ppath,
3677                                         int flags)
3678 {
3679         struct ext4_ext_path *path = *ppath;
3680         ext4_lblk_t eof_block;
3681         ext4_lblk_t ee_block;
3682         struct ext4_extent *ex;
3683         unsigned int ee_len;
3684         int split_flag = 0, depth;
3685
3686         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3687                   (unsigned long long)map->m_lblk, map->m_len);
3688
3689         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3690                         >> inode->i_sb->s_blocksize_bits;
3691         if (eof_block < map->m_lblk + map->m_len)
3692                 eof_block = map->m_lblk + map->m_len;
3693         /*
3694          * It is safe to convert extent to initialized via explicit
3695          * zeroout only if extent is fully inside i_size or new_size.
3696          */
3697         depth = ext_depth(inode);
3698         ex = path[depth].p_ext;
3699         ee_block = le32_to_cpu(ex->ee_block);
3700         ee_len = ext4_ext_get_actual_len(ex);
3701
3702         /* Convert to unwritten */
3703         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3704                 split_flag |= EXT4_EXT_DATA_VALID1;
3705         /* Convert to initialized */
3706         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3707                 split_flag |= ee_block + ee_len <= eof_block ?
3708                               EXT4_EXT_MAY_ZEROOUT : 0;
3709                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3710         }
3711         flags |= EXT4_GET_BLOCKS_PRE_IO;
3712         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3713 }
3714
3715 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3716                                                 struct inode *inode,
3717                                                 struct ext4_map_blocks *map,
3718                                                 struct ext4_ext_path **ppath)
3719 {
3720         struct ext4_ext_path *path = *ppath;
3721         struct ext4_extent *ex;
3722         ext4_lblk_t ee_block;
3723         unsigned int ee_len;
3724         int depth;
3725         int err = 0;
3726
3727         depth = ext_depth(inode);
3728         ex = path[depth].p_ext;
3729         ee_block = le32_to_cpu(ex->ee_block);
3730         ee_len = ext4_ext_get_actual_len(ex);
3731
3732         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3733                   (unsigned long long)ee_block, ee_len);
3734
3735         /* If extent is larger than requested it is a clear sign that we still
3736          * have some extent state machine issues left. So extent_split is still
3737          * required.
3738          * TODO: Once all related issues will be fixed this situation should be
3739          * illegal.
3740          */
3741         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3742 #ifdef CONFIG_EXT4_DEBUG
3743                 ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3744                              " len %u; IO logical block %llu, len %u",
3745                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3746                              (unsigned long long)map->m_lblk, map->m_len);
3747 #endif
3748                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3749                                                  EXT4_GET_BLOCKS_CONVERT);
3750                 if (err < 0)
3751                         return err;
3752                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3753                 if (IS_ERR(path))
3754                         return PTR_ERR(path);
3755                 depth = ext_depth(inode);
3756                 ex = path[depth].p_ext;
3757         }
3758
3759         err = ext4_ext_get_access(handle, inode, path + depth);
3760         if (err)
3761                 goto out;
3762         /* first mark the extent as initialized */
3763         ext4_ext_mark_initialized(ex);
3764
3765         /* note: ext4_ext_correct_indexes() isn't needed here because
3766          * borders are not changed
3767          */
3768         ext4_ext_try_to_merge(handle, inode, path, ex);
3769
3770         /* Mark modified extent as dirty */
3771         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3772 out:
3773         ext4_ext_show_leaf(inode, path);
3774         return err;
3775 }
3776
3777 static int
3778 convert_initialized_extent(handle_t *handle, struct inode *inode,
3779                            struct ext4_map_blocks *map,
3780                            struct ext4_ext_path **ppath,
3781                            unsigned int *allocated)
3782 {
3783         struct ext4_ext_path *path = *ppath;
3784         struct ext4_extent *ex;
3785         ext4_lblk_t ee_block;
3786         unsigned int ee_len;
3787         int depth;
3788         int err = 0;
3789
3790         /*
3791          * Make sure that the extent is no bigger than we support with
3792          * unwritten extent
3793          */
3794         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3795                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3796
3797         depth = ext_depth(inode);
3798         ex = path[depth].p_ext;
3799         ee_block = le32_to_cpu(ex->ee_block);
3800         ee_len = ext4_ext_get_actual_len(ex);
3801
3802         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3803                   (unsigned long long)ee_block, ee_len);
3804
3805         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3806                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3807                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3808                 if (err < 0)
3809                         return err;
3810                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3811                 if (IS_ERR(path))
3812                         return PTR_ERR(path);
3813                 depth = ext_depth(inode);
3814                 ex = path[depth].p_ext;
3815                 if (!ex) {
3816                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3817                                          (unsigned long) map->m_lblk);
3818                         return -EFSCORRUPTED;
3819                 }
3820         }
3821
3822         err = ext4_ext_get_access(handle, inode, path + depth);
3823         if (err)
3824                 return err;
3825         /* first mark the extent as unwritten */
3826         ext4_ext_mark_unwritten(ex);
3827
3828         /* note: ext4_ext_correct_indexes() isn't needed here because
3829          * borders are not changed
3830          */
3831         ext4_ext_try_to_merge(handle, inode, path, ex);
3832
3833         /* Mark modified extent as dirty */
3834         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3835         if (err)
3836                 return err;
3837         ext4_ext_show_leaf(inode, path);
3838
3839         ext4_update_inode_fsync_trans(handle, inode, 1);
3840
3841         map->m_flags |= EXT4_MAP_UNWRITTEN;
3842         if (*allocated > map->m_len)
3843                 *allocated = map->m_len;
3844         map->m_len = *allocated;
3845         return 0;
3846 }
3847
3848 static int
3849 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3850                         struct ext4_map_blocks *map,
3851                         struct ext4_ext_path **ppath, int flags,
3852                         unsigned int allocated, ext4_fsblk_t newblock)
3853 {
3854         struct ext4_ext_path __maybe_unused *path = *ppath;
3855         int ret = 0;
3856         int err = 0;
3857
3858         ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
3859                   (unsigned long long)map->m_lblk, map->m_len, flags,
3860                   allocated);
3861         ext4_ext_show_leaf(inode, path);
3862
3863         /*
3864          * When writing into unwritten space, we should not fail to
3865          * allocate metadata blocks for the new extent block if needed.
3866          */
3867         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3868
3869         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
3870                                                     allocated, newblock);
3871
3872         /* get_block() before submitting IO, split the extent */
3873         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
3874                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
3875                                          flags | EXT4_GET_BLOCKS_CONVERT);
3876                 if (ret < 0) {
3877                         err = ret;
3878                         goto out2;
3879                 }
3880                 /*
3881                  * shouldn't get a 0 return when splitting an extent unless
3882                  * m_len is 0 (bug) or extent has been corrupted
3883                  */
3884                 if (unlikely(ret == 0)) {
3885                         EXT4_ERROR_INODE(inode,
3886                                          "unexpected ret == 0, m_len = %u",
3887                                          map->m_len);
3888                         err = -EFSCORRUPTED;
3889                         goto out2;
3890                 }
3891                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3892                 goto out;
3893         }
3894         /* IO end_io complete, convert the filled extent to written */
3895         if (flags & EXT4_GET_BLOCKS_CONVERT) {
3896                 err = ext4_convert_unwritten_extents_endio(handle, inode, map,
3897                                                            ppath);
3898                 if (err < 0)
3899                         goto out2;
3900                 ext4_update_inode_fsync_trans(handle, inode, 1);
3901                 goto map_out;
3902         }
3903         /* buffered IO cases */
3904         /*
3905          * repeat fallocate creation request
3906          * we already have an unwritten extent
3907          */
3908         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
3909                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3910                 goto map_out;
3911         }
3912
3913         /* buffered READ or buffered write_begin() lookup */
3914         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3915                 /*
3916                  * We have blocks reserved already.  We
3917                  * return allocated blocks so that delalloc
3918                  * won't do block reservation for us.  But
3919                  * the buffer head will be unmapped so that
3920                  * a read from the block returns 0s.
3921                  */
3922                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3923                 goto out1;
3924         }
3925
3926         /*
3927          * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
3928          * For buffered writes, at writepage time, etc.  Convert a
3929          * discovered unwritten extent to written.
3930          */
3931         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
3932         if (ret < 0) {
3933                 err = ret;
3934                 goto out2;
3935         }
3936         ext4_update_inode_fsync_trans(handle, inode, 1);
3937         /*
3938          * shouldn't get a 0 return when converting an unwritten extent
3939          * unless m_len is 0 (bug) or extent has been corrupted
3940          */
3941         if (unlikely(ret == 0)) {
3942                 EXT4_ERROR_INODE(inode, "unexpected ret == 0, m_len = %u",
3943                                  map->m_len);
3944                 err = -EFSCORRUPTED;
3945                 goto out2;
3946         }
3947
3948 out:
3949         allocated = ret;
3950         map->m_flags |= EXT4_MAP_NEW;
3951 map_out:
3952         map->m_flags |= EXT4_MAP_MAPPED;
3953 out1:
3954         map->m_pblk = newblock;
3955         if (allocated > map->m_len)
3956                 allocated = map->m_len;
3957         map->m_len = allocated;
3958         ext4_ext_show_leaf(inode, path);
3959 out2:
3960         return err ? err : allocated;
3961 }
3962
3963 /*
3964  * get_implied_cluster_alloc - check to see if the requested
3965  * allocation (in the map structure) overlaps with a cluster already
3966  * allocated in an extent.
3967  *      @sb     The filesystem superblock structure
3968  *      @map    The requested lblk->pblk mapping
3969  *      @ex     The extent structure which might contain an implied
3970  *                      cluster allocation
3971  *
3972  * This function is called by ext4_ext_map_blocks() after we failed to
3973  * find blocks that were already in the inode's extent tree.  Hence,
3974  * we know that the beginning of the requested region cannot overlap
3975  * the extent from the inode's extent tree.  There are three cases we
3976  * want to catch.  The first is this case:
3977  *
3978  *               |--- cluster # N--|
3979  *    |--- extent ---|  |---- requested region ---|
3980  *                      |==========|
3981  *
3982  * The second case that we need to test for is this one:
3983  *
3984  *   |--------- cluster # N ----------------|
3985  *         |--- requested region --|   |------- extent ----|
3986  *         |=======================|
3987  *
3988  * The third case is when the requested region lies between two extents
3989  * within the same cluster:
3990  *          |------------- cluster # N-------------|
3991  * |----- ex -----|                  |---- ex_right ----|
3992  *                  |------ requested region ------|
3993  *                  |================|
3994  *
3995  * In each of the above cases, we need to set the map->m_pblk and
3996  * map->m_len so it corresponds to the return the extent labelled as
3997  * "|====|" from cluster #N, since it is already in use for data in
3998  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
3999  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4000  * as a new "allocated" block region.  Otherwise, we will return 0 and
4001  * ext4_ext_map_blocks() will then allocate one or more new clusters
4002  * by calling ext4_mb_new_blocks().
4003  */
4004 static int get_implied_cluster_alloc(struct super_block *sb,
4005                                      struct ext4_map_blocks *map,
4006                                      struct ext4_extent *ex,
4007                                      struct ext4_ext_path *path)
4008 {
4009         struct ext4_sb_info *sbi = EXT4_SB(sb);
4010         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4011         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4012         ext4_lblk_t rr_cluster_start;
4013         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4014         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4015         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4016
4017         /* The extent passed in that we are trying to match */
4018         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4019         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4020
4021         /* The requested region passed into ext4_map_blocks() */
4022         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4023
4024         if ((rr_cluster_start == ex_cluster_end) ||
4025             (rr_cluster_start == ex_cluster_start)) {
4026                 if (rr_cluster_start == ex_cluster_end)
4027                         ee_start += ee_len - 1;
4028                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4029                 map->m_len = min(map->m_len,
4030                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4031                 /*
4032                  * Check for and handle this case:
4033                  *
4034                  *   |--------- cluster # N-------------|
4035                  *                     |------- extent ----|
4036                  *         |--- requested region ---|
4037                  *         |===========|
4038                  */
4039
4040                 if (map->m_lblk < ee_block)
4041                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4042
4043                 /*
4044                  * Check for the case where there is already another allocated
4045                  * block to the right of 'ex' but before the end of the cluster.
4046                  *
4047                  *          |------------- cluster # N-------------|
4048                  * |----- ex -----|                  |---- ex_right ----|
4049                  *                  |------ requested region ------|
4050                  *                  |================|
4051                  */
4052                 if (map->m_lblk > ee_block) {
4053                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4054                         map->m_len = min(map->m_len, next - map->m_lblk);
4055                 }
4056
4057                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4058                 return 1;
4059         }
4060
4061         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4062         return 0;
4063 }
4064
4065
4066 /*
4067  * Block allocation/map/preallocation routine for extents based files
4068  *
4069  *
4070  * Need to be called with
4071  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4072  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4073  *
4074  * return > 0, number of blocks already mapped/allocated
4075  *          if create == 0 and these are pre-allocated blocks
4076  *              buffer head is unmapped
4077  *          otherwise blocks are mapped
4078  *
4079  * return = 0, if plain look up failed (blocks have not been allocated)
4080  *          buffer head is unmapped
4081  *
4082  * return < 0, error case.
4083  */
4084 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4085                         struct ext4_map_blocks *map, int flags)
4086 {
4087         struct ext4_ext_path *path = NULL;
4088         struct ext4_extent newex, *ex, ex2;
4089         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4090         ext4_fsblk_t newblock = 0, pblk;
4091         int err = 0, depth, ret;
4092         unsigned int allocated = 0, offset = 0;
4093         unsigned int allocated_clusters = 0;
4094         struct ext4_allocation_request ar;
4095         ext4_lblk_t cluster_offset;
4096
4097         ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
4098         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4099
4100         /* find extent for this block */
4101         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4102         if (IS_ERR(path)) {
4103                 err = PTR_ERR(path);
4104                 path = NULL;
4105                 goto out;
4106         }
4107
4108         depth = ext_depth(inode);
4109
4110         /*
4111          * consistent leaf must not be empty;
4112          * this situation is possible, though, _during_ tree modification;
4113          * this is why assert can't be put in ext4_find_extent()
4114          */
4115         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4116                 EXT4_ERROR_INODE(inode, "bad extent address "
4117                                  "lblock: %lu, depth: %d pblock %lld",
4118                                  (unsigned long) map->m_lblk, depth,
4119                                  path[depth].p_block);
4120                 err = -EFSCORRUPTED;
4121                 goto out;
4122         }
4123
4124         ex = path[depth].p_ext;
4125         if (ex) {
4126                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4127                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4128                 unsigned short ee_len;
4129
4130
4131                 /*
4132                  * unwritten extents are treated as holes, except that
4133                  * we split out initialized portions during a write.
4134                  */
4135                 ee_len = ext4_ext_get_actual_len(ex);
4136
4137                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4138
4139                 /* if found extent covers block, simply return it */
4140                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4141                         newblock = map->m_lblk - ee_block + ee_start;
4142                         /* number of remaining blocks in the extent */
4143                         allocated = ee_len - (map->m_lblk - ee_block);
4144                         ext_debug(inode, "%u fit into %u:%d -> %llu\n",
4145                                   map->m_lblk, ee_block, ee_len, newblock);
4146
4147                         /*
4148                          * If the extent is initialized check whether the
4149                          * caller wants to convert it to unwritten.
4150                          */
4151                         if ((!ext4_ext_is_unwritten(ex)) &&
4152                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4153                                 err = convert_initialized_extent(handle,
4154                                         inode, map, &path, &allocated);
4155                                 goto out;
4156                         } else if (!ext4_ext_is_unwritten(ex)) {
4157                                 map->m_flags |= EXT4_MAP_MAPPED;
4158                                 map->m_pblk = newblock;
4159                                 if (allocated > map->m_len)
4160                                         allocated = map->m_len;
4161                                 map->m_len = allocated;
4162                                 ext4_ext_show_leaf(inode, path);
4163                                 goto out;
4164                         }
4165
4166                         ret = ext4_ext_handle_unwritten_extents(
4167                                 handle, inode, map, &path, flags,
4168                                 allocated, newblock);
4169                         if (ret < 0)
4170                                 err = ret;
4171                         else
4172                                 allocated = ret;
4173                         goto out;
4174                 }
4175         }
4176
4177         /*
4178          * requested block isn't allocated yet;
4179          * we couldn't try to create block if create flag is zero
4180          */
4181         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4182                 ext4_lblk_t hole_start, hole_len;
4183
4184                 hole_start = map->m_lblk;
4185                 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4186                 /*
4187                  * put just found gap into cache to speed up
4188                  * subsequent requests
4189                  */
4190                 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4191
4192                 /* Update hole_len to reflect hole size after map->m_lblk */
4193                 if (hole_start != map->m_lblk)
4194                         hole_len -= map->m_lblk - hole_start;
4195                 map->m_pblk = 0;
4196                 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4197
4198                 goto out;
4199         }
4200
4201         /*
4202          * Okay, we need to do block allocation.
4203          */
4204         newex.ee_block = cpu_to_le32(map->m_lblk);
4205         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4206
4207         /*
4208          * If we are doing bigalloc, check to see if the extent returned
4209          * by ext4_find_extent() implies a cluster we can use.
4210          */
4211         if (cluster_offset && ex &&
4212             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4213                 ar.len = allocated = map->m_len;
4214                 newblock = map->m_pblk;
4215                 goto got_allocated_blocks;
4216         }
4217
4218         /* find neighbour allocated blocks */
4219         ar.lleft = map->m_lblk;
4220         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4221         if (err)
4222                 goto out;
4223         ar.lright = map->m_lblk;
4224         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4225         if (err < 0)
4226                 goto out;
4227
4228         /* Check if the extent after searching to the right implies a
4229          * cluster we can use. */
4230         if ((sbi->s_cluster_ratio > 1) && err &&
4231             get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
4232                 ar.len = allocated = map->m_len;
4233                 newblock = map->m_pblk;
4234                 goto got_allocated_blocks;
4235         }
4236
4237         /*
4238          * See if request is beyond maximum number of blocks we can have in
4239          * a single extent. For an initialized extent this limit is
4240          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4241          * EXT_UNWRITTEN_MAX_LEN.
4242          */
4243         if (map->m_len > EXT_INIT_MAX_LEN &&
4244             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4245                 map->m_len = EXT_INIT_MAX_LEN;
4246         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4247                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4248                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4249
4250         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4251         newex.ee_len = cpu_to_le16(map->m_len);
4252         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4253         if (err)
4254                 allocated = ext4_ext_get_actual_len(&newex);
4255         else
4256                 allocated = map->m_len;
4257
4258         /* allocate new block */
4259         ar.inode = inode;
4260         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4261         ar.logical = map->m_lblk;
4262         /*
4263          * We calculate the offset from the beginning of the cluster
4264          * for the logical block number, since when we allocate a
4265          * physical cluster, the physical block should start at the
4266          * same offset from the beginning of the cluster.  This is
4267          * needed so that future calls to get_implied_cluster_alloc()
4268          * work correctly.
4269          */
4270         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4271         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4272         ar.goal -= offset;
4273         ar.logical -= offset;
4274         if (S_ISREG(inode->i_mode))
4275                 ar.flags = EXT4_MB_HINT_DATA;
4276         else
4277                 /* disable in-core preallocation for non-regular files */
4278                 ar.flags = 0;
4279         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4280                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4281         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4282                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4283         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4284                 ar.flags |= EXT4_MB_USE_RESERVED;
4285         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4286         if (!newblock)
4287                 goto out;
4288         allocated_clusters = ar.len;
4289         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4290         ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
4291                   ar.goal, newblock, ar.len, allocated);
4292         if (ar.len > allocated)
4293                 ar.len = allocated;
4294
4295 got_allocated_blocks:
4296         /* try to insert new extent into found leaf and return */
4297         pblk = newblock + offset;
4298         ext4_ext_store_pblock(&newex, pblk);
4299         newex.ee_len = cpu_to_le16(ar.len);
4300         /* Mark unwritten */
4301         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4302                 ext4_ext_mark_unwritten(&newex);
4303                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4304         }
4305
4306         err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags);
4307         if (err) {
4308                 if (allocated_clusters) {
4309                         int fb_flags = 0;
4310
4311                         /*
4312                          * free data blocks we just allocated.
4313                          * not a good idea to call discard here directly,
4314                          * but otherwise we'd need to call it every free().
4315                          */
4316                         ext4_discard_preallocations(inode, 0);
4317                         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4318                                 fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
4319                         ext4_free_blocks(handle, inode, NULL, newblock,
4320                                          EXT4_C2B(sbi, allocated_clusters),
4321                                          fb_flags);
4322                 }
4323                 goto out;
4324         }
4325
4326         /*
4327          * Reduce the reserved cluster count to reflect successful deferred
4328          * allocation of delayed allocated clusters or direct allocation of
4329          * clusters discovered to be delayed allocated.  Once allocated, a
4330          * cluster is not included in the reserved count.
4331          */
4332         if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
4333                 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4334                         /*
4335                          * When allocating delayed allocated clusters, simply
4336                          * reduce the reserved cluster count and claim quota
4337                          */
4338                         ext4_da_update_reserve_space(inode, allocated_clusters,
4339                                                         1);
4340                 } else {
4341                         ext4_lblk_t lblk, len;
4342                         unsigned int n;
4343
4344                         /*
4345                          * When allocating non-delayed allocated clusters
4346                          * (from fallocate, filemap, DIO, or clusters
4347                          * allocated when delalloc has been disabled by
4348                          * ext4_nonda_switch), reduce the reserved cluster
4349                          * count by the number of allocated clusters that
4350                          * have previously been delayed allocated.  Quota
4351                          * has been claimed by ext4_mb_new_blocks() above,
4352                          * so release the quota reservations made for any
4353                          * previously delayed allocated clusters.
4354                          */
4355                         lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4356                         len = allocated_clusters << sbi->s_cluster_bits;
4357                         n = ext4_es_delayed_clu(inode, lblk, len);
4358                         if (n > 0)
4359                                 ext4_da_update_reserve_space(inode, (int) n, 0);
4360                 }
4361         }
4362
4363         /*
4364          * Cache the extent and update transaction to commit on fdatasync only
4365          * when it is _not_ an unwritten extent.
4366          */
4367         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4368                 ext4_update_inode_fsync_trans(handle, inode, 1);
4369         else
4370                 ext4_update_inode_fsync_trans(handle, inode, 0);
4371
4372         map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
4373         map->m_pblk = pblk;
4374         map->m_len = ar.len;
4375         allocated = map->m_len;
4376         ext4_ext_show_leaf(inode, path);
4377 out:
4378         ext4_free_ext_path(path);
4379
4380         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4381                                        err ? err : allocated);
4382         return err ? err : allocated;
4383 }
4384
4385 int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4386 {
4387         struct super_block *sb = inode->i_sb;
4388         ext4_lblk_t last_block;
4389         int err = 0;
4390
4391         /*
4392          * TODO: optimization is possible here.
4393          * Probably we need not scan at all,
4394          * because page truncation is enough.
4395          */
4396
4397         /* we have to know where to truncate from in crash case */
4398         EXT4_I(inode)->i_disksize = inode->i_size;
4399         err = ext4_mark_inode_dirty(handle, inode);
4400         if (err)
4401                 return err;
4402
4403         last_block = (inode->i_size + sb->s_blocksize - 1)
4404                         >> EXT4_BLOCK_SIZE_BITS(sb);
4405         ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);
4406
4407 retry_remove_space:
4408         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4409         if (err == -ENOMEM) {
4410                 memalloc_retry_wait(GFP_ATOMIC);
4411                 goto retry_remove_space;
4412         }
4413         return err;
4414 }
4415
4416 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4417                                   ext4_lblk_t len, loff_t new_size,
4418                                   int flags)
4419 {
4420         struct inode *inode = file_inode(file);
4421         handle_t *handle;
4422         int ret = 0, ret2 = 0, ret3 = 0;
4423         int retries = 0;
4424         int depth = 0;
4425         struct ext4_map_blocks map;
4426         unsigned int credits;
4427         loff_t epos;
4428
4429         BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4430         map.m_lblk = offset;
4431         map.m_len = len;
4432         /*
4433          * Don't normalize the request if it can fit in one extent so
4434          * that it doesn't get unnecessarily split into multiple
4435          * extents.
4436          */
4437         if (len <= EXT_UNWRITTEN_MAX_LEN)
4438                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4439
4440         /*
4441          * credits to insert 1 extent into extent tree
4442          */
4443         credits = ext4_chunk_trans_blocks(inode, len);
4444         depth = ext_depth(inode);
4445
4446 retry:
4447         while (len) {
4448                 /*
4449                  * Recalculate credits when extent tree depth changes.
4450                  */
4451                 if (depth != ext_depth(inode)) {
4452                         credits = ext4_chunk_trans_blocks(inode, len);
4453                         depth = ext_depth(inode);
4454                 }
4455
4456                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4457                                             credits);
4458                 if (IS_ERR(handle)) {
4459                         ret = PTR_ERR(handle);
4460                         break;
4461                 }
4462                 ret = ext4_map_blocks(handle, inode, &map, flags);
4463                 if (ret <= 0) {
4464                         ext4_debug("inode #%lu: block %u: len %u: "
4465                                    "ext4_ext_map_blocks returned %d",
4466                                    inode->i_ino, map.m_lblk,
4467                                    map.m_len, ret);
4468                         ext4_mark_inode_dirty(handle, inode);
4469                         ext4_journal_stop(handle);
4470                         break;
4471                 }
4472                 /*
4473                  * allow a full retry cycle for any remaining allocations
4474                  */
4475                 retries = 0;
4476                 map.m_lblk += ret;
4477                 map.m_len = len = len - ret;
4478                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4479                 inode_set_ctime_current(inode);
4480                 if (new_size) {
4481                         if (epos > new_size)
4482                                 epos = new_size;
4483                         if (ext4_update_inode_size(inode, epos) & 0x1)
4484                                 inode->i_mtime = inode_get_ctime(inode);
4485                 }
4486                 ret2 = ext4_mark_inode_dirty(handle, inode);
4487                 ext4_update_inode_fsync_trans(handle, inode, 1);
4488                 ret3 = ext4_journal_stop(handle);
4489                 ret2 = ret3 ? ret3 : ret2;
4490                 if (unlikely(ret2))
4491                         break;
4492         }
4493         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
4494                 goto retry;
4495
4496         return ret > 0 ? ret2 : ret;
4497 }
4498
4499 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);
4500
4501 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
4502
4503 static long ext4_zero_range(struct file *file, loff_t offset,
4504                             loff_t len, int mode)
4505 {
4506         struct inode *inode = file_inode(file);
4507         struct address_space *mapping = file->f_mapping;
4508         handle_t *handle = NULL;
4509         unsigned int max_blocks;
4510         loff_t new_size = 0;
4511         int ret = 0;
4512         int flags;
4513         int credits;
4514         int partial_begin, partial_end;
4515         loff_t start, end;
4516         ext4_lblk_t lblk;
4517         unsigned int blkbits = inode->i_blkbits;
4518
4519         trace_ext4_zero_range(inode, offset, len, mode);
4520
4521         /*
4522          * Round up offset. This is not fallocate, we need to zero out
4523          * blocks, so convert interior block aligned part of the range to
4524          * unwritten and possibly manually zero out unaligned parts of the
4525          * range.
4526          */
4527         start = round_up(offset, 1 << blkbits);
4528         end = round_down((offset + len), 1 << blkbits);
4529
4530         if (start < offset || end > offset + len)
4531                 return -EINVAL;
4532         partial_begin = offset & ((1 << blkbits) - 1);
4533         partial_end = (offset + len) & ((1 << blkbits) - 1);
4534
4535         lblk = start >> blkbits;
4536         max_blocks = (end >> blkbits);
4537         if (max_blocks < lblk)
4538                 max_blocks = 0;
4539         else
4540                 max_blocks -= lblk;
4541
4542         inode_lock(inode);
4543
4544         /*
4545          * Indirect files do not support unwritten extents
4546          */
4547         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4548                 ret = -EOPNOTSUPP;
4549                 goto out_mutex;
4550         }
4551
4552         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4553             (offset + len > inode->i_size ||
4554              offset + len > EXT4_I(inode)->i_disksize)) {
4555                 new_size = offset + len;
4556                 ret = inode_newsize_ok(inode, new_size);
4557                 if (ret)
4558                         goto out_mutex;
4559         }
4560
4561         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4562
4563         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4564         inode_dio_wait(inode);
4565
4566         ret = file_modified(file);
4567         if (ret)
4568                 goto out_mutex;
4569
4570         /* Preallocate the range including the unaligned edges */
4571         if (partial_begin || partial_end) {
4572                 ret = ext4_alloc_file_blocks(file,
4573                                 round_down(offset, 1 << blkbits) >> blkbits,
4574                                 (round_up((offset + len), 1 << blkbits) -
4575                                  round_down(offset, 1 << blkbits)) >> blkbits,
4576                                 new_size, flags);
4577                 if (ret)
4578                         goto out_mutex;
4579
4580         }
4581
4582         /* Zero range excluding the unaligned edges */
4583         if (max_blocks > 0) {
4584                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4585                           EXT4_EX_NOCACHE);
4586
4587                 /*
4588                  * Prevent page faults from reinstantiating pages we have
4589                  * released from page cache.
4590                  */
4591                 filemap_invalidate_lock(mapping);
4592
4593                 ret = ext4_break_layouts(inode);
4594                 if (ret) {
4595                         filemap_invalidate_unlock(mapping);
4596                         goto out_mutex;
4597                 }
4598
4599                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4600                 if (ret) {
4601                         filemap_invalidate_unlock(mapping);
4602                         goto out_mutex;
4603                 }
4604
4605                 /*
4606                  * For journalled data we need to write (and checkpoint) pages
4607                  * before discarding page cache to avoid inconsitent data on
4608                  * disk in case of crash before zeroing trans is committed.
4609                  */
4610                 if (ext4_should_journal_data(inode)) {
4611                         ret = filemap_write_and_wait_range(mapping, start, end);
4612                         if (ret) {
4613                                 filemap_invalidate_unlock(mapping);
4614                                 goto out_mutex;
4615                         }
4616                 }
4617
4618                 /* Now release the pages and zero block aligned part of pages */
4619                 truncate_pagecache_range(inode, start, end - 1);
4620                 inode->i_mtime = inode_set_ctime_current(inode);
4621
4622                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4623                                              flags);
4624                 filemap_invalidate_unlock(mapping);
4625                 if (ret)
4626                         goto out_mutex;
4627         }
4628         if (!partial_begin && !partial_end)
4629                 goto out_mutex;
4630
4631         /*
4632          * In worst case we have to writeout two nonadjacent unwritten
4633          * blocks and update the inode
4634          */
4635         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4636         if (ext4_should_journal_data(inode))
4637                 credits += 2;
4638         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4639         if (IS_ERR(handle)) {
4640                 ret = PTR_ERR(handle);
4641                 ext4_std_error(inode->i_sb, ret);
4642                 goto out_mutex;
4643         }
4644
4645         inode->i_mtime = inode_set_ctime_current(inode);
4646         if (new_size)
4647                 ext4_update_inode_size(inode, new_size);
4648         ret = ext4_mark_inode_dirty(handle, inode);
4649         if (unlikely(ret))
4650                 goto out_handle;
4651         /* Zero out partial block at the edges of the range */
4652         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4653         if (ret >= 0)
4654                 ext4_update_inode_fsync_trans(handle, inode, 1);
4655
4656         if (file->f_flags & O_SYNC)
4657                 ext4_handle_sync(handle);
4658
4659 out_handle:
4660         ext4_journal_stop(handle);
4661 out_mutex:
4662         inode_unlock(inode);
4663         return ret;
4664 }
4665
4666 /*
4667  * preallocate space for a file. This implements ext4's fallocate file
4668  * operation, which gets called from sys_fallocate system call.
4669  * For block-mapped files, posix_fallocate should fall back to the method
4670  * of writing zeroes to the required new blocks (the same behavior which is
4671  * expected for file systems which do not support fallocate() system call).
4672  */
4673 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4674 {
4675         struct inode *inode = file_inode(file);
4676         loff_t new_size = 0;
4677         unsigned int max_blocks;
4678         int ret = 0;
4679         int flags;
4680         ext4_lblk_t lblk;
4681         unsigned int blkbits = inode->i_blkbits;
4682
4683         /*
4684          * Encrypted inodes can't handle collapse range or insert
4685          * range since we would need to re-encrypt blocks with a
4686          * different IV or XTS tweak (which are based on the logical
4687          * block number).
4688          */
4689         if (IS_ENCRYPTED(inode) &&
4690             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
4691                 return -EOPNOTSUPP;
4692
4693         /* Return error if mode is not supported */
4694         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4695                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4696                      FALLOC_FL_INSERT_RANGE))
4697                 return -EOPNOTSUPP;
4698
4699         inode_lock(inode);
4700         ret = ext4_convert_inline_data(inode);
4701         inode_unlock(inode);
4702         if (ret)
4703                 goto exit;
4704
4705         if (mode & FALLOC_FL_PUNCH_HOLE) {
4706                 ret = ext4_punch_hole(file, offset, len);
4707                 goto exit;
4708         }
4709
4710         if (mode & FALLOC_FL_COLLAPSE_RANGE) {
4711                 ret = ext4_collapse_range(file, offset, len);
4712                 goto exit;
4713         }
4714
4715         if (mode & FALLOC_FL_INSERT_RANGE) {
4716                 ret = ext4_insert_range(file, offset, len);
4717                 goto exit;
4718         }
4719
4720         if (mode & FALLOC_FL_ZERO_RANGE) {
4721                 ret = ext4_zero_range(file, offset, len, mode);
4722                 goto exit;
4723         }
4724         trace_ext4_fallocate_enter(inode, offset, len, mode);
4725         lblk = offset >> blkbits;
4726
4727         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4728         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4729
4730         inode_lock(inode);
4731
4732         /*
4733          * We only support preallocation for extent-based files only
4734          */
4735         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4736                 ret = -EOPNOTSUPP;
4737                 goto out;
4738         }
4739
4740         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4741             (offset + len > inode->i_size ||
4742              offset + len > EXT4_I(inode)->i_disksize)) {
4743                 new_size = offset + len;
4744                 ret = inode_newsize_ok(inode, new_size);
4745                 if (ret)
4746                         goto out;
4747         }
4748
4749         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4750         inode_dio_wait(inode);
4751
4752         ret = file_modified(file);
4753         if (ret)
4754                 goto out;
4755
4756         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4757         if (ret)
4758                 goto out;
4759
4760         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4761                 ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
4762                                         EXT4_I(inode)->i_sync_tid);
4763         }
4764 out:
4765         inode_unlock(inode);
4766         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4767 exit:
4768         return ret;
4769 }
4770
4771 /*
4772  * This function convert a range of blocks to written extents
4773  * The caller of this function will pass the start offset and the size.
4774  * all unwritten extents within this range will be converted to
4775  * written extents.
4776  *
4777  * This function is called from the direct IO end io call back
4778  * function, to convert the fallocated extents after IO is completed.
4779  * Returns 0 on success.
4780  */
4781 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4782                                    loff_t offset, ssize_t len)
4783 {
4784         unsigned int max_blocks;
4785         int ret = 0, ret2 = 0, ret3 = 0;
4786         struct ext4_map_blocks map;
4787         unsigned int blkbits = inode->i_blkbits;
4788         unsigned int credits = 0;
4789
4790         map.m_lblk = offset >> blkbits;
4791         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4792
4793         if (!handle) {
4794                 /*
4795                  * credits to insert 1 extent into extent tree
4796                  */
4797                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4798         }
4799         while (ret >= 0 && ret < max_blocks) {
4800                 map.m_lblk += ret;
4801                 map.m_len = (max_blocks -= ret);
4802                 if (credits) {
4803                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4804                                                     credits);
4805                         if (IS_ERR(handle)) {
4806                                 ret = PTR_ERR(handle);
4807                                 break;
4808                         }
4809                 }
4810                 ret = ext4_map_blocks(handle, inode, &map,
4811                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4812                 if (ret <= 0)
4813                         ext4_warning(inode->i_sb,
4814                                      "inode #%lu: block %u: len %u: "
4815                                      "ext4_ext_map_blocks returned %d",
4816                                      inode->i_ino, map.m_lblk,
4817                                      map.m_len, ret);
4818                 ret2 = ext4_mark_inode_dirty(handle, inode);
4819                 if (credits) {
4820                         ret3 = ext4_journal_stop(handle);
4821                         if (unlikely(ret3))
4822                                 ret2 = ret3;
4823                 }
4824
4825                 if (ret <= 0 || ret2)
4826                         break;
4827         }
4828         return ret > 0 ? ret2 : ret;
4829 }
4830
4831 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
4832 {
4833         int ret = 0, err = 0;
4834         struct ext4_io_end_vec *io_end_vec;
4835
4836         /*
4837          * This is somewhat ugly but the idea is clear: When transaction is
4838          * reserved, everything goes into it. Otherwise we rather start several
4839          * smaller transactions for conversion of each extent separately.
4840          */
4841         if (handle) {
4842                 handle = ext4_journal_start_reserved(handle,
4843                                                      EXT4_HT_EXT_CONVERT);
4844                 if (IS_ERR(handle))
4845                         return PTR_ERR(handle);
4846         }
4847
4848         list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4849                 ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4850                                                      io_end_vec->offset,
4851                                                      io_end_vec->size);
4852                 if (ret)
4853                         break;
4854         }
4855
4856         if (handle)
4857                 err = ext4_journal_stop(handle);
4858
4859         return ret < 0 ? ret : err;
4860 }
4861
4862 static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
4863 {
4864         __u64 physical = 0;
4865         __u64 length = 0;
4866         int blockbits = inode->i_sb->s_blocksize_bits;
4867         int error = 0;
4868         u16 iomap_type;
4869
4870         /* in-inode? */
4871         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4872                 struct ext4_iloc iloc;
4873                 int offset;     /* offset of xattr in inode */
4874
4875                 error = ext4_get_inode_loc(inode, &iloc);
4876                 if (error)
4877                         return error;
4878                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
4879                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4880                                 EXT4_I(inode)->i_extra_isize;
4881                 physical += offset;
4882                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4883                 brelse(iloc.bh);
4884                 iomap_type = IOMAP_INLINE;
4885         } else if (EXT4_I(inode)->i_file_acl) { /* external block */
4886                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4887                 length = inode->i_sb->s_blocksize;
4888                 iomap_type = IOMAP_MAPPED;
4889         } else {
4890                 /* no in-inode or external block for xattr, so return -ENOENT */
4891                 error = -ENOENT;
4892                 goto out;
4893         }
4894
4895         iomap->addr = physical;
4896         iomap->offset = 0;
4897         iomap->length = length;
4898         iomap->type = iomap_type;
4899         iomap->flags = 0;
4900 out:
4901         return error;
4902 }
4903
4904 static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
4905                                   loff_t length, unsigned flags,
4906                                   struct iomap *iomap, struct iomap *srcmap)
4907 {
4908         int error;
4909
4910         error = ext4_iomap_xattr_fiemap(inode, iomap);
4911         if (error == 0 && (offset >= iomap->length))
4912                 error = -ENOENT;
4913         return error;
4914 }
4915
4916 static const struct iomap_ops ext4_iomap_xattr_ops = {
4917         .iomap_begin            = ext4_iomap_xattr_begin,
4918 };
4919
4920 static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
4921 {
4922         u64 maxbytes;
4923
4924         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4925                 maxbytes = inode->i_sb->s_maxbytes;
4926         else
4927                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
4928
4929         if (*len == 0)
4930                 return -EINVAL;
4931         if (start > maxbytes)
4932                 return -EFBIG;
4933
4934         /*
4935          * Shrink request scope to what the fs can actually handle.
4936          */
4937         if (*len > maxbytes || (maxbytes - *len) < start)
4938                 *len = maxbytes - start;
4939         return 0;
4940 }
4941
4942 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4943                 u64 start, u64 len)
4944 {
4945         int error = 0;
4946
4947         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4948                 error = ext4_ext_precache(inode);
4949                 if (error)
4950                         return error;
4951                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4952         }
4953
4954         /*
4955          * For bitmap files the maximum size limit could be smaller than
4956          * s_maxbytes, so check len here manually instead of just relying on the
4957          * generic check.
4958          */
4959         error = ext4_fiemap_check_ranges(inode, start, &len);
4960         if (error)
4961                 return error;
4962
4963         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4964                 fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
4965                 return iomap_fiemap(inode, fieinfo, start, len,
4966                                     &ext4_iomap_xattr_ops);
4967         }
4968
4969         return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
4970 }
4971
4972 int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
4973                       __u64 start, __u64 len)
4974 {
4975         ext4_lblk_t start_blk, len_blks;
4976         __u64 last_blk;
4977         int error = 0;
4978
4979         if (ext4_has_inline_data(inode)) {
4980                 int has_inline;
4981
4982                 down_read(&EXT4_I(inode)->xattr_sem);
4983                 has_inline = ext4_has_inline_data(inode);
4984                 up_read(&EXT4_I(inode)->xattr_sem);
4985                 if (has_inline)
4986                         return 0;
4987         }
4988
4989         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4990                 error = ext4_ext_precache(inode);
4991                 if (error)
4992                         return error;
4993                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4994         }
4995
4996         error = fiemap_prep(inode, fieinfo, start, &len, 0);
4997         if (error)
4998                 return error;
4999
5000         error = ext4_fiemap_check_ranges(inode, start, &len);
5001         if (error)
5002                 return error;
5003
5004         start_blk = start >> inode->i_sb->s_blocksize_bits;
5005         last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5006         if (last_blk >= EXT_MAX_BLOCKS)
5007                 last_blk = EXT_MAX_BLOCKS-1;
5008         len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5009
5010         /*
5011          * Walk the extent tree gathering extent information
5012          * and pushing extents back to the user.
5013          */
5014         return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
5015 }
5016
5017 /*
5018  * ext4_ext_shift_path_extents:
5019  * Shift the extents of a path structure lying between path[depth].p_ext
5020  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5021  * if it is right shift or left shift operation.
5022  */
5023 static int
5024 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5025                             struct inode *inode, handle_t *handle,
5026                             enum SHIFT_DIRECTION SHIFT)
5027 {
5028         int depth, err = 0;
5029         struct ext4_extent *ex_start, *ex_last;
5030         bool update = false;
5031         int credits, restart_credits;
5032         depth = path->p_depth;
5033
5034         while (depth >= 0) {
5035                 if (depth == path->p_depth) {
5036                         ex_start = path[depth].p_ext;
5037                         if (!ex_start)
5038                                 return -EFSCORRUPTED;
5039
5040                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5041                         /* leaf + sb + inode */
5042                         credits = 3;
5043                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
5044                                 update = true;
5045                                 /* extent tree + sb + inode */
5046                                 credits = depth + 2;
5047                         }
5048
5049                         restart_credits = ext4_writepage_trans_blocks(inode);
5050                         err = ext4_datasem_ensure_credits(handle, inode, credits,
5051                                         restart_credits, 0);
5052                         if (err) {
5053                                 if (err > 0)
5054                                         err = -EAGAIN;
5055                                 goto out;
5056                         }
5057
5058                         err = ext4_ext_get_access(handle, inode, path + depth);
5059                         if (err)
5060                                 goto out;
5061
5062                         while (ex_start <= ex_last) {
5063                                 if (SHIFT == SHIFT_LEFT) {
5064                                         le32_add_cpu(&ex_start->ee_block,
5065                                                 -shift);
5066                                         /* Try to merge to the left. */
5067                                         if ((ex_start >
5068                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5069                                             &&
5070                                             ext4_ext_try_to_merge_right(inode,
5071                                             path, ex_start - 1))
5072                                                 ex_last--;
5073                                         else
5074                                                 ex_start++;
5075                                 } else {
5076                                         le32_add_cpu(&ex_last->ee_block, shift);
5077                                         ext4_ext_try_to_merge_right(inode, path,
5078                                                 ex_last);
5079                                         ex_last--;
5080                                 }
5081                         }
5082                         err = ext4_ext_dirty(handle, inode, path + depth);
5083                         if (err)
5084                                 goto out;
5085
5086                         if (--depth < 0 || !update)
5087                                 break;
5088                 }
5089
5090                 /* Update index too */
5091                 err = ext4_ext_get_access(handle, inode, path + depth);
5092                 if (err)
5093                         goto out;
5094
5095                 if (SHIFT == SHIFT_LEFT)
5096                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5097                 else
5098                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5099                 err = ext4_ext_dirty(handle, inode, path + depth);
5100                 if (err)
5101                         goto out;
5102
5103                 /* we are done if current index is not a starting index */
5104                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5105                         break;
5106
5107                 depth--;
5108         }
5109
5110 out:
5111         return err;
5112 }
5113
5114 /*
5115  * ext4_ext_shift_extents:
5116  * All the extents which lies in the range from @start to the last allocated
5117  * block for the @inode are shifted either towards left or right (depending
5118  * upon @SHIFT) by @shift blocks.
5119  * On success, 0 is returned, error otherwise.
5120  */
5121 static int
5122 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5123                        ext4_lblk_t start, ext4_lblk_t shift,
5124                        enum SHIFT_DIRECTION SHIFT)
5125 {
5126         struct ext4_ext_path *path;
5127         int ret = 0, depth;
5128         struct ext4_extent *extent;
5129         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5130         ext4_lblk_t tmp = EXT_MAX_BLOCKS;
5131
5132         /* Let path point to the last extent */
5133         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5134                                 EXT4_EX_NOCACHE);
5135         if (IS_ERR(path))
5136                 return PTR_ERR(path);
5137
5138         depth = path->p_depth;
5139         extent = path[depth].p_ext;
5140         if (!extent)
5141                 goto out;
5142
5143         stop = le32_to_cpu(extent->ee_block);
5144
5145        /*
5146         * For left shifts, make sure the hole on the left is big enough to
5147         * accommodate the shift.  For right shifts, make sure the last extent
5148         * won't be shifted beyond EXT_MAX_BLOCKS.
5149         */
5150         if (SHIFT == SHIFT_LEFT) {
5151                 path = ext4_find_extent(inode, start - 1, &path,
5152                                         EXT4_EX_NOCACHE);
5153                 if (IS_ERR(path))
5154                         return PTR_ERR(path);
5155                 depth = path->p_depth;
5156                 extent =  path[depth].p_ext;
5157                 if (extent) {
5158                         ex_start = le32_to_cpu(extent->ee_block);
5159                         ex_end = le32_to_cpu(extent->ee_block) +
5160                                 ext4_ext_get_actual_len(extent);
5161                 } else {
5162                         ex_start = 0;
5163                         ex_end = 0;
5164                 }
5165
5166                 if ((start == ex_start && shift > ex_start) ||
5167                     (shift > start - ex_end)) {
5168                         ret = -EINVAL;
5169                         goto out;
5170                 }
5171         } else {
5172                 if (shift > EXT_MAX_BLOCKS -
5173                     (stop + ext4_ext_get_actual_len(extent))) {
5174                         ret = -EINVAL;
5175                         goto out;
5176                 }
5177         }
5178
5179         /*
5180          * In case of left shift, iterator points to start and it is increased
5181          * till we reach stop. In case of right shift, iterator points to stop
5182          * and it is decreased till we reach start.
5183          */
5184 again:
5185         ret = 0;
5186         if (SHIFT == SHIFT_LEFT)
5187                 iterator = &start;
5188         else
5189                 iterator = &stop;
5190
5191         if (tmp != EXT_MAX_BLOCKS)
5192                 *iterator = tmp;
5193
5194         /*
5195          * Its safe to start updating extents.  Start and stop are unsigned, so
5196          * in case of right shift if extent with 0 block is reached, iterator
5197          * becomes NULL to indicate the end of the loop.
5198          */
5199         while (iterator && start <= stop) {
5200                 path = ext4_find_extent(inode, *iterator, &path,
5201                                         EXT4_EX_NOCACHE);
5202                 if (IS_ERR(path))
5203                         return PTR_ERR(path);
5204                 depth = path->p_depth;
5205                 extent = path[depth].p_ext;
5206                 if (!extent) {
5207                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5208                                          (unsigned long) *iterator);
5209                         return -EFSCORRUPTED;
5210                 }
5211                 if (SHIFT == SHIFT_LEFT && *iterator >
5212                     le32_to_cpu(extent->ee_block)) {
5213                         /* Hole, move to the next extent */
5214                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5215                                 path[depth].p_ext++;
5216                         } else {
5217                                 *iterator = ext4_ext_next_allocated_block(path);
5218                                 continue;
5219                         }
5220                 }
5221
5222                 tmp = *iterator;
5223                 if (SHIFT == SHIFT_LEFT) {
5224                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5225                         *iterator = le32_to_cpu(extent->ee_block) +
5226                                         ext4_ext_get_actual_len(extent);
5227                 } else {
5228                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5229                         if (le32_to_cpu(extent->ee_block) > start)
5230                                 *iterator = le32_to_cpu(extent->ee_block) - 1;
5231                         else if (le32_to_cpu(extent->ee_block) == start)
5232                                 iterator = NULL;
5233                         else {
5234                                 extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5235                                 while (le32_to_cpu(extent->ee_block) >= start)
5236                                         extent--;
5237
5238                                 if (extent == EXT_LAST_EXTENT(path[depth].p_hdr))
5239                                         break;
5240
5241                                 extent++;
5242                                 iterator = NULL;
5243                         }
5244                         path[depth].p_ext = extent;
5245                 }
5246                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5247                                 handle, SHIFT);
5248                 /* iterator can be NULL which means we should break */
5249                 if (ret == -EAGAIN)
5250                         goto again;
5251                 if (ret)
5252                         break;
5253         }
5254 out:
5255         ext4_free_ext_path(path);
5256         return ret;
5257 }
5258
5259 /*
5260  * ext4_collapse_range:
5261  * This implements the fallocate's collapse range functionality for ext4
5262  * Returns: 0 and non-zero on error.
5263  */
5264 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)
5265 {
5266         struct inode *inode = file_inode(file);
5267         struct super_block *sb = inode->i_sb;
5268         struct address_space *mapping = inode->i_mapping;
5269         ext4_lblk_t punch_start, punch_stop;
5270         handle_t *handle;
5271         unsigned int credits;
5272         loff_t new_size, ioffset;
5273         int ret;
5274
5275         /*
5276          * We need to test this early because xfstests assumes that a
5277          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5278          * system does not support collapse range.
5279          */
5280         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5281                 return -EOPNOTSUPP;
5282
5283         /* Collapse range works only on fs cluster size aligned regions. */
5284         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5285                 return -EINVAL;
5286
5287         trace_ext4_collapse_range(inode, offset, len);
5288
5289         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5290         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5291
5292         inode_lock(inode);
5293         /*
5294          * There is no need to overlap collapse range with EOF, in which case
5295          * it is effectively a truncate operation
5296          */
5297         if (offset + len >= inode->i_size) {
5298                 ret = -EINVAL;
5299                 goto out_mutex;
5300         }
5301
5302         /* Currently just for extent based files */
5303         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5304                 ret = -EOPNOTSUPP;
5305                 goto out_mutex;
5306         }
5307
5308         /* Wait for existing dio to complete */
5309         inode_dio_wait(inode);
5310
5311         ret = file_modified(file);
5312         if (ret)
5313                 goto out_mutex;
5314
5315         /*
5316          * Prevent page faults from reinstantiating pages we have released from
5317          * page cache.
5318          */
5319         filemap_invalidate_lock(mapping);
5320
5321         ret = ext4_break_layouts(inode);
5322         if (ret)
5323                 goto out_mmap;
5324
5325         /*
5326          * Need to round down offset to be aligned with page size boundary
5327          * for page size > block size.
5328          */
5329         ioffset = round_down(offset, PAGE_SIZE);
5330         /*
5331          * Write tail of the last page before removed range since it will get
5332          * removed from the page cache below.
5333          */
5334         ret = filemap_write_and_wait_range(mapping, ioffset, offset);
5335         if (ret)
5336                 goto out_mmap;
5337         /*
5338          * Write data that will be shifted to preserve them when discarding
5339          * page cache below. We are also protected from pages becoming dirty
5340          * by i_rwsem and invalidate_lock.
5341          */
5342         ret = filemap_write_and_wait_range(mapping, offset + len,
5343                                            LLONG_MAX);
5344         if (ret)
5345                 goto out_mmap;
5346         truncate_pagecache(inode, ioffset);
5347
5348         credits = ext4_writepage_trans_blocks(inode);
5349         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5350         if (IS_ERR(handle)) {
5351                 ret = PTR_ERR(handle);
5352                 goto out_mmap;
5353         }
5354         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5355
5356         down_write(&EXT4_I(inode)->i_data_sem);
5357         ext4_discard_preallocations(inode, 0);
5358         ext4_es_remove_extent(inode, punch_start, EXT_MAX_BLOCKS - punch_start);
5359
5360         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5361         if (ret) {
5362                 up_write(&EXT4_I(inode)->i_data_sem);
5363                 goto out_stop;
5364         }
5365         ext4_discard_preallocations(inode, 0);
5366
5367         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5368                                      punch_stop - punch_start, SHIFT_LEFT);
5369         if (ret) {
5370                 up_write(&EXT4_I(inode)->i_data_sem);
5371                 goto out_stop;
5372         }
5373
5374         new_size = inode->i_size - len;
5375         i_size_write(inode, new_size);
5376         EXT4_I(inode)->i_disksize = new_size;
5377
5378         up_write(&EXT4_I(inode)->i_data_sem);
5379         if (IS_SYNC(inode))
5380                 ext4_handle_sync(handle);
5381         inode->i_mtime = inode_set_ctime_current(inode);
5382         ret = ext4_mark_inode_dirty(handle, inode);
5383         ext4_update_inode_fsync_trans(handle, inode, 1);
5384
5385 out_stop:
5386         ext4_journal_stop(handle);
5387 out_mmap:
5388         filemap_invalidate_unlock(mapping);
5389 out_mutex:
5390         inode_unlock(inode);
5391         return ret;
5392 }
5393
5394 /*
5395  * ext4_insert_range:
5396  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5397  * The data blocks starting from @offset to the EOF are shifted by @len
5398  * towards right to create a hole in the @inode. Inode size is increased
5399  * by len bytes.
5400  * Returns 0 on success, error otherwise.
5401  */
5402 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
5403 {
5404         struct inode *inode = file_inode(file);
5405         struct super_block *sb = inode->i_sb;
5406         struct address_space *mapping = inode->i_mapping;
5407         handle_t *handle;
5408         struct ext4_ext_path *path;
5409         struct ext4_extent *extent;
5410         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5411         unsigned int credits, ee_len;
5412         int ret = 0, depth, split_flag = 0;
5413         loff_t ioffset;
5414
5415         /*
5416          * We need to test this early because xfstests assumes that an
5417          * insert range of (0, 1) will return EOPNOTSUPP if the file
5418          * system does not support insert range.
5419          */
5420         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5421                 return -EOPNOTSUPP;
5422
5423         /* Insert range works only on fs cluster size aligned regions. */
5424         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5425                 return -EINVAL;
5426
5427         trace_ext4_insert_range(inode, offset, len);
5428
5429         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5430         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5431
5432         inode_lock(inode);
5433         /* Currently just for extent based files */
5434         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5435                 ret = -EOPNOTSUPP;
5436                 goto out_mutex;
5437         }
5438
5439         /* Check whether the maximum file size would be exceeded */
5440         if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5441                 ret = -EFBIG;
5442                 goto out_mutex;
5443         }
5444
5445         /* Offset must be less than i_size */
5446         if (offset >= inode->i_size) {
5447                 ret = -EINVAL;
5448                 goto out_mutex;
5449         }
5450
5451         /* Wait for existing dio to complete */
5452         inode_dio_wait(inode);
5453
5454         ret = file_modified(file);
5455         if (ret)
5456                 goto out_mutex;
5457
5458         /*
5459          * Prevent page faults from reinstantiating pages we have released from
5460          * page cache.
5461          */
5462         filemap_invalidate_lock(mapping);
5463
5464         ret = ext4_break_layouts(inode);
5465         if (ret)
5466                 goto out_mmap;
5467
5468         /*
5469          * Need to round down to align start offset to page size boundary
5470          * for page size > block size.
5471          */
5472         ioffset = round_down(offset, PAGE_SIZE);
5473         /* Write out all dirty pages */
5474         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5475                         LLONG_MAX);
5476         if (ret)
5477                 goto out_mmap;
5478         truncate_pagecache(inode, ioffset);
5479
5480         credits = ext4_writepage_trans_blocks(inode);
5481         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5482         if (IS_ERR(handle)) {
5483                 ret = PTR_ERR(handle);
5484                 goto out_mmap;
5485         }
5486         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5487
5488         /* Expand file to avoid data loss if there is error while shifting */
5489         inode->i_size += len;
5490         EXT4_I(inode)->i_disksize += len;
5491         inode->i_mtime = inode_set_ctime_current(inode);
5492         ret = ext4_mark_inode_dirty(handle, inode);
5493         if (ret)
5494                 goto out_stop;
5495
5496         down_write(&EXT4_I(inode)->i_data_sem);
5497         ext4_discard_preallocations(inode, 0);
5498
5499         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5500         if (IS_ERR(path)) {
5501                 up_write(&EXT4_I(inode)->i_data_sem);
5502                 goto out_stop;
5503         }
5504
5505         depth = ext_depth(inode);
5506         extent = path[depth].p_ext;
5507         if (extent) {
5508                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5509                 ee_len = ext4_ext_get_actual_len(extent);
5510
5511                 /*
5512                  * If offset_lblk is not the starting block of extent, split
5513                  * the extent @offset_lblk
5514                  */
5515                 if ((offset_lblk > ee_start_lblk) &&
5516                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5517                         if (ext4_ext_is_unwritten(extent))
5518                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5519                                         EXT4_EXT_MARK_UNWRIT2;
5520                         ret = ext4_split_extent_at(handle, inode, &path,
5521                                         offset_lblk, split_flag,
5522                                         EXT4_EX_NOCACHE |
5523                                         EXT4_GET_BLOCKS_PRE_IO |
5524                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5525                 }
5526
5527                 ext4_free_ext_path(path);
5528                 if (ret < 0) {
5529                         up_write(&EXT4_I(inode)->i_data_sem);
5530                         goto out_stop;
5531                 }
5532         } else {
5533                 ext4_free_ext_path(path);
5534         }
5535
5536         ext4_es_remove_extent(inode, offset_lblk, EXT_MAX_BLOCKS - offset_lblk);
5537
5538         /*
5539          * if offset_lblk lies in a hole which is at start of file, use
5540          * ee_start_lblk to shift extents
5541          */
5542         ret = ext4_ext_shift_extents(inode, handle,
5543                 max(ee_start_lblk, offset_lblk), len_lblk, SHIFT_RIGHT);
5544
5545         up_write(&EXT4_I(inode)->i_data_sem);
5546         if (IS_SYNC(inode))
5547                 ext4_handle_sync(handle);
5548         if (ret >= 0)
5549                 ext4_update_inode_fsync_trans(handle, inode, 1);
5550
5551 out_stop:
5552         ext4_journal_stop(handle);
5553 out_mmap:
5554         filemap_invalidate_unlock(mapping);
5555 out_mutex:
5556         inode_unlock(inode);
5557         return ret;
5558 }
5559
5560 /**
5561  * ext4_swap_extents() - Swap extents between two inodes
5562  * @handle: handle for this transaction
5563  * @inode1:     First inode
5564  * @inode2:     Second inode
5565  * @lblk1:      Start block for first inode
5566  * @lblk2:      Start block for second inode
5567  * @count:      Number of blocks to swap
5568  * @unwritten: Mark second inode's extents as unwritten after swap
5569  * @erp:        Pointer to save error value
5570  *
5571  * This helper routine does exactly what is promise "swap extents". All other
5572  * stuff such as page-cache locking consistency, bh mapping consistency or
5573  * extent's data copying must be performed by caller.
5574  * Locking:
5575  *              i_rwsem is held for both inodes
5576  *              i_data_sem is locked for write for both inodes
5577  * Assumptions:
5578  *              All pages from requested range are locked for both inodes
5579  */
5580 int
5581 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5582                   struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5583                   ext4_lblk_t count, int unwritten, int *erp)
5584 {
5585         struct ext4_ext_path *path1 = NULL;
5586         struct ext4_ext_path *path2 = NULL;
5587         int replaced_count = 0;
5588
5589         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5590         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5591         BUG_ON(!inode_is_locked(inode1));
5592         BUG_ON(!inode_is_locked(inode2));
5593
5594         ext4_es_remove_extent(inode1, lblk1, count);
5595         ext4_es_remove_extent(inode2, lblk2, count);
5596
5597         while (count) {
5598                 struct ext4_extent *ex1, *ex2, tmp_ex;
5599                 ext4_lblk_t e1_blk, e2_blk;
5600                 int e1_len, e2_len, len;
5601                 int split = 0;
5602
5603                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5604                 if (IS_ERR(path1)) {
5605                         *erp = PTR_ERR(path1);
5606                         path1 = NULL;
5607                 finish:
5608                         count = 0;
5609                         goto repeat;
5610                 }
5611                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5612                 if (IS_ERR(path2)) {
5613                         *erp = PTR_ERR(path2);
5614                         path2 = NULL;
5615                         goto finish;
5616                 }
5617                 ex1 = path1[path1->p_depth].p_ext;
5618                 ex2 = path2[path2->p_depth].p_ext;
5619                 /* Do we have something to swap ? */
5620                 if (unlikely(!ex2 || !ex1))
5621                         goto finish;
5622
5623                 e1_blk = le32_to_cpu(ex1->ee_block);
5624                 e2_blk = le32_to_cpu(ex2->ee_block);
5625                 e1_len = ext4_ext_get_actual_len(ex1);
5626                 e2_len = ext4_ext_get_actual_len(ex2);
5627
5628                 /* Hole handling */
5629                 if (!in_range(lblk1, e1_blk, e1_len) ||
5630                     !in_range(lblk2, e2_blk, e2_len)) {
5631                         ext4_lblk_t next1, next2;
5632
5633                         /* if hole after extent, then go to next extent */
5634                         next1 = ext4_ext_next_allocated_block(path1);
5635                         next2 = ext4_ext_next_allocated_block(path2);
5636                         /* If hole before extent, then shift to that extent */
5637                         if (e1_blk > lblk1)
5638                                 next1 = e1_blk;
5639                         if (e2_blk > lblk2)
5640                                 next2 = e2_blk;
5641                         /* Do we have something to swap */
5642                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5643                                 goto finish;
5644                         /* Move to the rightest boundary */
5645                         len = next1 - lblk1;
5646                         if (len < next2 - lblk2)
5647                                 len = next2 - lblk2;
5648                         if (len > count)
5649                                 len = count;
5650                         lblk1 += len;
5651                         lblk2 += len;
5652                         count -= len;
5653                         goto repeat;
5654                 }
5655
5656                 /* Prepare left boundary */
5657                 if (e1_blk < lblk1) {
5658                         split = 1;
5659                         *erp = ext4_force_split_extent_at(handle, inode1,
5660                                                 &path1, lblk1, 0);
5661                         if (unlikely(*erp))
5662                                 goto finish;
5663                 }
5664                 if (e2_blk < lblk2) {
5665                         split = 1;
5666                         *erp = ext4_force_split_extent_at(handle, inode2,
5667                                                 &path2,  lblk2, 0);
5668                         if (unlikely(*erp))
5669                                 goto finish;
5670                 }
5671                 /* ext4_split_extent_at() may result in leaf extent split,
5672                  * path must to be revalidated. */
5673                 if (split)
5674                         goto repeat;
5675
5676                 /* Prepare right boundary */
5677                 len = count;
5678                 if (len > e1_blk + e1_len - lblk1)
5679                         len = e1_blk + e1_len - lblk1;
5680                 if (len > e2_blk + e2_len - lblk2)
5681                         len = e2_blk + e2_len - lblk2;
5682
5683                 if (len != e1_len) {
5684                         split = 1;
5685                         *erp = ext4_force_split_extent_at(handle, inode1,
5686                                                 &path1, lblk1 + len, 0);
5687                         if (unlikely(*erp))
5688                                 goto finish;
5689                 }
5690                 if (len != e2_len) {
5691                         split = 1;
5692                         *erp = ext4_force_split_extent_at(handle, inode2,
5693                                                 &path2, lblk2 + len, 0);
5694                         if (*erp)
5695                                 goto finish;
5696                 }
5697                 /* ext4_split_extent_at() may result in leaf extent split,
5698                  * path must to be revalidated. */
5699                 if (split)
5700                         goto repeat;
5701
5702                 BUG_ON(e2_len != e1_len);
5703                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5704                 if (unlikely(*erp))
5705                         goto finish;
5706                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5707                 if (unlikely(*erp))
5708                         goto finish;
5709
5710                 /* Both extents are fully inside boundaries. Swap it now */
5711                 tmp_ex = *ex1;
5712                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5713                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5714                 ex1->ee_len = cpu_to_le16(e2_len);
5715                 ex2->ee_len = cpu_to_le16(e1_len);
5716                 if (unwritten)
5717                         ext4_ext_mark_unwritten(ex2);
5718                 if (ext4_ext_is_unwritten(&tmp_ex))
5719                         ext4_ext_mark_unwritten(ex1);
5720
5721                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5722                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5723                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5724                                       path2->p_depth);
5725                 if (unlikely(*erp))
5726                         goto finish;
5727                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5728                                       path1->p_depth);
5729                 /*
5730                  * Looks scarry ah..? second inode already points to new blocks,
5731                  * and it was successfully dirtied. But luckily error may happen
5732                  * only due to journal error, so full transaction will be
5733                  * aborted anyway.
5734                  */
5735                 if (unlikely(*erp))
5736                         goto finish;
5737                 lblk1 += len;
5738                 lblk2 += len;
5739                 replaced_count += len;
5740                 count -= len;
5741
5742         repeat:
5743                 ext4_free_ext_path(path1);
5744                 ext4_free_ext_path(path2);
5745                 path1 = path2 = NULL;
5746         }
5747         return replaced_count;
5748 }
5749
5750 /*
5751  * ext4_clu_mapped - determine whether any block in a logical cluster has
5752  *                   been mapped to a physical cluster
5753  *
5754  * @inode - file containing the logical cluster
5755  * @lclu - logical cluster of interest
5756  *
5757  * Returns 1 if any block in the logical cluster is mapped, signifying
5758  * that a physical cluster has been allocated for it.  Otherwise,
5759  * returns 0.  Can also return negative error codes.  Derived from
5760  * ext4_ext_map_blocks().
5761  */
5762 int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5763 {
5764         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5765         struct ext4_ext_path *path;
5766         int depth, mapped = 0, err = 0;
5767         struct ext4_extent *extent;
5768         ext4_lblk_t first_lblk, first_lclu, last_lclu;
5769
5770         /*
5771          * if data can be stored inline, the logical cluster isn't
5772          * mapped - no physical clusters have been allocated, and the
5773          * file has no extents
5774          */
5775         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) ||
5776             ext4_has_inline_data(inode))
5777                 return 0;
5778
5779         /* search for the extent closest to the first block in the cluster */
5780         path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5781         if (IS_ERR(path)) {
5782                 err = PTR_ERR(path);
5783                 path = NULL;
5784                 goto out;
5785         }
5786
5787         depth = ext_depth(inode);
5788
5789         /*
5790          * A consistent leaf must not be empty.  This situation is possible,
5791          * though, _during_ tree modification, and it's why an assert can't
5792          * be put in ext4_find_extent().
5793          */
5794         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5795                 EXT4_ERROR_INODE(inode,
5796                     "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5797                                  (unsigned long) EXT4_C2B(sbi, lclu),
5798                                  depth, path[depth].p_block);
5799                 err = -EFSCORRUPTED;
5800                 goto out;
5801         }
5802
5803         extent = path[depth].p_ext;
5804
5805         /* can't be mapped if the extent tree is empty */
5806         if (extent == NULL)
5807                 goto out;
5808
5809         first_lblk = le32_to_cpu(extent->ee_block);
5810         first_lclu = EXT4_B2C(sbi, first_lblk);
5811
5812         /*
5813          * Three possible outcomes at this point - found extent spanning
5814          * the target cluster, to the left of the target cluster, or to the
5815          * right of the target cluster.  The first two cases are handled here.
5816          * The last case indicates the target cluster is not mapped.
5817          */
5818         if (lclu >= first_lclu) {
5819                 last_lclu = EXT4_B2C(sbi, first_lblk +
5820                                      ext4_ext_get_actual_len(extent) - 1);
5821                 if (lclu <= last_lclu) {
5822                         mapped = 1;
5823                 } else {
5824                         first_lblk = ext4_ext_next_allocated_block(path);
5825                         first_lclu = EXT4_B2C(sbi, first_lblk);
5826                         if (lclu == first_lclu)
5827                                 mapped = 1;
5828                 }
5829         }
5830
5831 out:
5832         ext4_free_ext_path(path);
5833
5834         return err ? err : mapped;
5835 }
5836
5837 /*
5838  * Updates physical block address and unwritten status of extent
5839  * starting at lblk start and of len. If such an extent doesn't exist,
5840  * this function splits the extent tree appropriately to create an
5841  * extent like this.  This function is called in the fast commit
5842  * replay path.  Returns 0 on success and error on failure.
5843  */
5844 int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
5845                               int len, int unwritten, ext4_fsblk_t pblk)
5846 {
5847         struct ext4_ext_path *path = NULL, *ppath;
5848         struct ext4_extent *ex;
5849         int ret;
5850
5851         path = ext4_find_extent(inode, start, NULL, 0);
5852         if (IS_ERR(path))
5853                 return PTR_ERR(path);
5854         ex = path[path->p_depth].p_ext;
5855         if (!ex) {
5856                 ret = -EFSCORRUPTED;
5857                 goto out;
5858         }
5859
5860         if (le32_to_cpu(ex->ee_block) != start ||
5861                 ext4_ext_get_actual_len(ex) != len) {
5862                 /* We need to split this extent to match our extent first */
5863                 ppath = path;
5864                 down_write(&EXT4_I(inode)->i_data_sem);
5865                 ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
5866                 up_write(&EXT4_I(inode)->i_data_sem);
5867                 if (ret)
5868                         goto out;
5869                 kfree(path);
5870                 path = ext4_find_extent(inode, start, NULL, 0);
5871                 if (IS_ERR(path))
5872                         return -1;
5873                 ppath = path;
5874                 ex = path[path->p_depth].p_ext;
5875                 WARN_ON(le32_to_cpu(ex->ee_block) != start);
5876                 if (ext4_ext_get_actual_len(ex) != len) {
5877                         down_write(&EXT4_I(inode)->i_data_sem);
5878                         ret = ext4_force_split_extent_at(NULL, inode, &ppath,
5879                                                          start + len, 1);
5880                         up_write(&EXT4_I(inode)->i_data_sem);
5881                         if (ret)
5882                                 goto out;
5883                         kfree(path);
5884                         path = ext4_find_extent(inode, start, NULL, 0);
5885                         if (IS_ERR(path))
5886                                 return -EINVAL;
5887                         ex = path[path->p_depth].p_ext;
5888                 }
5889         }
5890         if (unwritten)
5891                 ext4_ext_mark_unwritten(ex);
5892         else
5893                 ext4_ext_mark_initialized(ex);
5894         ext4_ext_store_pblock(ex, pblk);
5895         down_write(&EXT4_I(inode)->i_data_sem);
5896         ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5897         up_write(&EXT4_I(inode)->i_data_sem);
5898 out:
5899         ext4_free_ext_path(path);
5900         ext4_mark_inode_dirty(NULL, inode);
5901         return ret;
5902 }
5903
5904 /* Try to shrink the extent tree */
5905 void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
5906 {
5907         struct ext4_ext_path *path = NULL;
5908         struct ext4_extent *ex;
5909         ext4_lblk_t old_cur, cur = 0;
5910
5911         while (cur < end) {
5912                 path = ext4_find_extent(inode, cur, NULL, 0);
5913                 if (IS_ERR(path))
5914                         return;
5915                 ex = path[path->p_depth].p_ext;
5916                 if (!ex) {
5917                         ext4_free_ext_path(path);
5918                         ext4_mark_inode_dirty(NULL, inode);
5919                         return;
5920                 }
5921                 old_cur = cur;
5922                 cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5923                 if (cur <= old_cur)
5924                         cur = old_cur + 1;
5925                 ext4_ext_try_to_merge(NULL, inode, path, ex);
5926                 down_write(&EXT4_I(inode)->i_data_sem);
5927                 ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5928                 up_write(&EXT4_I(inode)->i_data_sem);
5929                 ext4_mark_inode_dirty(NULL, inode);
5930                 ext4_free_ext_path(path);
5931         }
5932 }
5933
5934 /* Check if *cur is a hole and if it is, skip it */
5935 static int skip_hole(struct inode *inode, ext4_lblk_t *cur)
5936 {
5937         int ret;
5938         struct ext4_map_blocks map;
5939
5940         map.m_lblk = *cur;
5941         map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
5942
5943         ret = ext4_map_blocks(NULL, inode, &map, 0);
5944         if (ret < 0)
5945                 return ret;
5946         if (ret != 0)
5947                 return 0;
5948         *cur = *cur + map.m_len;
5949         return 0;
5950 }
5951
5952 /* Count number of blocks used by this inode and update i_blocks */
5953 int ext4_ext_replay_set_iblocks(struct inode *inode)
5954 {
5955         struct ext4_ext_path *path = NULL, *path2 = NULL;
5956         struct ext4_extent *ex;
5957         ext4_lblk_t cur = 0, end;
5958         int numblks = 0, i, ret = 0;
5959         ext4_fsblk_t cmp1, cmp2;
5960         struct ext4_map_blocks map;
5961
5962         /* Determin the size of the file first */
5963         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5964                                         EXT4_EX_NOCACHE);
5965         if (IS_ERR(path))
5966                 return PTR_ERR(path);
5967         ex = path[path->p_depth].p_ext;
5968         if (!ex) {
5969                 ext4_free_ext_path(path);
5970                 goto out;
5971         }
5972         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5973         ext4_free_ext_path(path);
5974
5975         /* Count the number of data blocks */
5976         cur = 0;
5977         while (cur < end) {
5978                 map.m_lblk = cur;
5979                 map.m_len = end - cur;
5980                 ret = ext4_map_blocks(NULL, inode, &map, 0);
5981                 if (ret < 0)
5982                         break;
5983                 if (ret > 0)
5984                         numblks += ret;
5985                 cur = cur + map.m_len;
5986         }
5987
5988         /*
5989          * Count the number of extent tree blocks. We do it by looking up
5990          * two successive extents and determining the difference between
5991          * their paths. When path is different for 2 successive extents
5992          * we compare the blocks in the path at each level and increment
5993          * iblocks by total number of differences found.
5994          */
5995         cur = 0;
5996         ret = skip_hole(inode, &cur);
5997         if (ret < 0)
5998                 goto out;
5999         path = ext4_find_extent(inode, cur, NULL, 0);
6000         if (IS_ERR(path))
6001                 goto out;
6002         numblks += path->p_depth;
6003         ext4_free_ext_path(path);
6004         while (cur < end) {
6005                 path = ext4_find_extent(inode, cur, NULL, 0);
6006                 if (IS_ERR(path))
6007                         break;
6008                 ex = path[path->p_depth].p_ext;
6009                 if (!ex) {
6010                         ext4_free_ext_path(path);
6011                         return 0;
6012                 }
6013                 cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
6014                                         ext4_ext_get_actual_len(ex));
6015                 ret = skip_hole(inode, &cur);
6016                 if (ret < 0) {
6017                         ext4_free_ext_path(path);
6018                         break;
6019                 }
6020                 path2 = ext4_find_extent(inode, cur, NULL, 0);
6021                 if (IS_ERR(path2)) {
6022                         ext4_free_ext_path(path);
6023                         break;
6024                 }
6025                 for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
6026                         cmp1 = cmp2 = 0;
6027                         if (i <= path->p_depth)
6028                                 cmp1 = path[i].p_bh ?
6029                                         path[i].p_bh->b_blocknr : 0;
6030                         if (i <= path2->p_depth)
6031                                 cmp2 = path2[i].p_bh ?
6032                                         path2[i].p_bh->b_blocknr : 0;
6033                         if (cmp1 != cmp2 && cmp2 != 0)
6034                                 numblks++;
6035                 }
6036                 ext4_free_ext_path(path);
6037                 ext4_free_ext_path(path2);
6038         }
6039
6040 out:
6041         inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
6042         ext4_mark_inode_dirty(NULL, inode);
6043         return 0;
6044 }
6045
6046 int ext4_ext_clear_bb(struct inode *inode)
6047 {
6048         struct ext4_ext_path *path = NULL;
6049         struct ext4_extent *ex;
6050         ext4_lblk_t cur = 0, end;
6051         int j, ret = 0;
6052         struct ext4_map_blocks map;
6053
6054         if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA))
6055                 return 0;
6056
6057         /* Determin the size of the file first */
6058         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6059                                         EXT4_EX_NOCACHE);
6060         if (IS_ERR(path))
6061                 return PTR_ERR(path);
6062         ex = path[path->p_depth].p_ext;
6063         if (!ex) {
6064                 ext4_free_ext_path(path);
6065                 return 0;
6066         }
6067         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6068         ext4_free_ext_path(path);
6069
6070         cur = 0;
6071         while (cur < end) {
6072                 map.m_lblk = cur;
6073                 map.m_len = end - cur;
6074                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6075                 if (ret < 0)
6076                         break;
6077                 if (ret > 0) {
6078                         path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
6079                         if (!IS_ERR_OR_NULL(path)) {
6080                                 for (j = 0; j < path->p_depth; j++) {
6081
6082                                         ext4_mb_mark_bb(inode->i_sb,
6083                                                         path[j].p_block, 1, 0);
6084                                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6085                                                         0, path[j].p_block, 1, 1);
6086                                 }
6087                                 ext4_free_ext_path(path);
6088                         }
6089                         ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
6090                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6091                                         map.m_lblk, map.m_pblk, map.m_len, 1);
6092                 }
6093                 cur = cur + map.m_len;
6094         }
6095
6096         return 0;
6097 }