git.itanic.dy.fi Git - linux-stable/blob - fs/ext4/extents.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   4  * Written by Alex Tomas <alex@clusterfs.com>
   5  *
   6  * Architecture independence:
   7  *   Copyright (c) 2005, Bull S.A.
   8  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   9  */
  10
  11 /*
  12  * Extents support for EXT4
  13  *
  14  * TODO:
  15  *   - ext4*_error() should be used in some situations
  16  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  17  *   - smart tree reduction
  18  */
  19
  20 #include <linux/fs.h>
  21 #include <linux/time.h>
  22 #include <linux/jbd2.h>
  23 #include <linux/highuid.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/quotaops.h>
  26 #include <linux/string.h>
  27 #include <linux/slab.h>
  28 #include <linux/uaccess.h>
  29 #include <linux/fiemap.h>
  30 #include <linux/iomap.h>
  31 #include <linux/sched/mm.h>
  32 #include "ext4_jbd2.h"
  33 #include "ext4_extents.h"
  34 #include "xattr.h"
  35
  36 #include <trace/events/ext4.h>
  37
  38 /*
  39  * used by extent splitting.
  40  */
  41 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  42                                         due to ENOSPC */
  43 #define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  44 #define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  45
  46 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  47 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  48
  49 static __le32 ext4_extent_block_csum(struct inode *inode,
  50                                      struct ext4_extent_header *eh)
  51 {
  52         struct ext4_inode_info *ei = EXT4_I(inode);
  53         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  54         __u32 csum;
  55
  56         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  57                            EXT4_EXTENT_TAIL_OFFSET(eh));
  58         return cpu_to_le32(csum);
  59 }
  60
  61 static int ext4_extent_block_csum_verify(struct inode *inode,
  62                                          struct ext4_extent_header *eh)
  63 {
  64         struct ext4_extent_tail *et;
  65
  66         if (!ext4_has_metadata_csum(inode->i_sb))
  67                 return 1;
  68
  69         et = find_ext4_extent_tail(eh);
  70         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  71                 return 0;
  72         return 1;
  73 }
  74
  75 static void ext4_extent_block_csum_set(struct inode *inode,
  76                                        struct ext4_extent_header *eh)
  77 {
  78         struct ext4_extent_tail *et;
  79
  80         if (!ext4_has_metadata_csum(inode->i_sb))
  81                 return;
  82
  83         et = find_ext4_extent_tail(eh);
  84         et->et_checksum = ext4_extent_block_csum(inode, eh);
  85 }
  86
  87 static int ext4_split_extent_at(handle_t *handle,
  88                              struct inode *inode,
  89                              struct ext4_ext_path **ppath,
  90                              ext4_lblk_t split,
  91                              int split_flag,
  92                              int flags);
  93
  94 static int ext4_ext_trunc_restart_fn(struct inode *inode, int *dropped)
  95 {
  96         /*
  97          * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
  98          * moment, get_block can be called only for blocks inside i_size since
  99          * page cache has been already dropped and writes are blocked by
 100          * i_rwsem. So we can safely drop the i_data_sem here.
 101          */
 102         BUG_ON(EXT4_JOURNAL(inode) == NULL);
 103         ext4_discard_preallocations(inode, 0);
 104         up_write(&EXT4_I(inode)->i_data_sem);
 105         *dropped = 1;
 106         return 0;
 107 }
 108
 109 /*
 110  * Make sure 'handle' has at least 'check_cred' credits. If not, restart
 111  * transaction with 'restart_cred' credits. The function drops i_data_sem
 112  * when restarting transaction and gets it after transaction is restarted.
 113  *
 114  * The function returns 0 on success, 1 if transaction had to be restarted,
 115  * and < 0 in case of fatal error.
 116  */
 117 int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,
 118                                 int check_cred, int restart_cred,
 119                                 int revoke_cred)
 120 {
 121         int ret;
 122         int dropped = 0;
 123
 124         ret = ext4_journal_ensure_credits_fn(handle, check_cred, restart_cred,
 125                 revoke_cred, ext4_ext_trunc_restart_fn(inode, &dropped));
 126         if (dropped)
 127                 down_write(&EXT4_I(inode)->i_data_sem);
 128         return ret;
 129 }
 130
 131 /*
 132  * could return:
 133  *  - EROFS
 134  *  - ENOMEM
 135  */
 136 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 137                                 struct ext4_ext_path *path)
 138 {
 139         int err = 0;
 140
 141         if (path->p_bh) {
 142                 /* path points to block */
 143                 BUFFER_TRACE(path->p_bh, "get_write_access");
 144                 err = ext4_journal_get_write_access(handle, inode->i_sb,
 145                                                     path->p_bh, EXT4_JTR_NONE);
 146                 /*
 147                  * The extent buffer's verified bit will be set again in
 148                  * __ext4_ext_dirty(). We could leave an inconsistent
 149                  * buffer if the extents updating procudure break off du
 150                  * to some error happens, force to check it again.
 151                  */
 152                 if (!err)
 153                         clear_buffer_verified(path->p_bh);
 154         }
 155         /* path points to leaf/index in inode body */
 156         /* we use in-core data, no need to protect them */
 157         return err;
 158 }
 159
 160 /*
 161  * could return:
 162  *  - EROFS
 163  *  - ENOMEM
 164  *  - EIO
 165  */
 166 static int __ext4_ext_dirty(const char *where, unsigned int line,
 167                             handle_t *handle, struct inode *inode,
 168                             struct ext4_ext_path *path)
 169 {
 170         int err;
 171
 172         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 173         if (path->p_bh) {
 174                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 175                 /* path points to block */
 176                 err = __ext4_handle_dirty_metadata(where, line, handle,
 177                                                    inode, path->p_bh);
 178                 /* Extents updating done, re-set verified flag */
 179                 if (!err)
 180                         set_buffer_verified(path->p_bh);
 181         } else {
 182                 /* path points to leaf/index in inode body */
 183                 err = ext4_mark_inode_dirty(handle, inode);
 184         }
 185         return err;
 186 }
 187
 188 #define ext4_ext_dirty(handle, inode, path) \
 189                 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
 190
 191 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 192                               struct ext4_ext_path *path,
 193                               ext4_lblk_t block)
 194 {
 195         if (path) {
 196                 int depth = path->p_depth;
 197                 struct ext4_extent *ex;
 198
 199                 /*
 200                  * Try to predict block placement assuming that we are
 201                  * filling in a file which will eventually be
 202                  * non-sparse --- i.e., in the case of libbfd writing
 203                  * an ELF object sections out-of-order but in a way
 204                  * the eventually results in a contiguous object or
 205                  * executable file, or some database extending a table
 206                  * space file.  However, this is actually somewhat
 207                  * non-ideal if we are writing a sparse file such as
 208                  * qemu or KVM writing a raw image file that is going
 209                  * to stay fairly sparse, since it will end up
 210                  * fragmenting the file system's free space.  Maybe we
 211                  * should have some hueristics or some way to allow
 212                  * userspace to pass a hint to file system,
 213                  * especially if the latter case turns out to be
 214                  * common.
 215                  */
 216                 ex = path[depth].p_ext;
 217                 if (ex) {
 218                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 219                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 220
 221                         if (block > ext_block)
 222                                 return ext_pblk + (block - ext_block);
 223                         else
 224                                 return ext_pblk - (ext_block - block);
 225                 }
 226
 227                 /* it looks like index is empty;
 228                  * try to find starting block from index itself */
 229                 if (path[depth].p_bh)
 230                         return path[depth].p_bh->b_blocknr;
 231         }
 232
 233         /* OK. use inode's group */
 234         return ext4_inode_to_goal_block(inode);
 235 }
 236
 237 /*
 238  * Allocation for a meta data block
 239  */
 240 static ext4_fsblk_t
 241 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 242                         struct ext4_ext_path *path,
 243                         struct ext4_extent *ex, int *err, unsigned int flags)
 244 {
 245         ext4_fsblk_t goal, newblock;
 246
 247         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 248         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 249                                         NULL, err);
 250         return newblock;
 251 }
 252
 253 static inline int ext4_ext_space_block(struct inode *inode, int check)
 254 {
 255         int size;
 256
 257         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 258                         / sizeof(struct ext4_extent);
 259 #ifdef AGGRESSIVE_TEST
 260         if (!check && size > 6)
 261                 size = 6;
 262 #endif
 263         return size;
 264 }
 265
 266 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 267 {
 268         int size;
 269
 270         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 271                         / sizeof(struct ext4_extent_idx);
 272 #ifdef AGGRESSIVE_TEST
 273         if (!check && size > 5)
 274                 size = 5;
 275 #endif
 276         return size;
 277 }
 278
 279 static inline int ext4_ext_space_root(struct inode *inode, int check)
 280 {
 281         int size;
 282
 283         size = sizeof(EXT4_I(inode)->i_data);
 284         size -= sizeof(struct ext4_extent_header);
 285         size /= sizeof(struct ext4_extent);
 286 #ifdef AGGRESSIVE_TEST
 287         if (!check && size > 3)
 288                 size = 3;
 289 #endif
 290         return size;
 291 }
 292
 293 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 294 {
 295         int size;
 296
 297         size = sizeof(EXT4_I(inode)->i_data);
 298         size -= sizeof(struct ext4_extent_header);
 299         size /= sizeof(struct ext4_extent_idx);
 300 #ifdef AGGRESSIVE_TEST
 301         if (!check && size > 4)
 302                 size = 4;
 303 #endif
 304         return size;
 305 }
 306
 307 static inline int
 308 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 309                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 310                            int nofail)
 311 {
 312         struct ext4_ext_path *path = *ppath;
 313         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 314         int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO;
 315
 316         if (nofail)
 317                 flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL;
 318
 319         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 320                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 321                         flags);
 322 }
 323
 324 static int
 325 ext4_ext_max_entries(struct inode *inode, int depth)
 326 {
 327         int max;
 328
 329         if (depth == ext_depth(inode)) {
 330                 if (depth == 0)
 331                         max = ext4_ext_space_root(inode, 1);
 332                 else
 333                         max = ext4_ext_space_root_idx(inode, 1);
 334         } else {
 335                 if (depth == 0)
 336                         max = ext4_ext_space_block(inode, 1);
 337                 else
 338                         max = ext4_ext_space_block_idx(inode, 1);
 339         }
 340
 341         return max;
 342 }
 343
 344 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 345 {
 346         ext4_fsblk_t block = ext4_ext_pblock(ext);
 347         int len = ext4_ext_get_actual_len(ext);
 348         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 349
 350         /*
 351          * We allow neither:
 352          *  - zero length
 353          *  - overflow/wrap-around
 354          */
 355         if (lblock + len <= lblock)
 356                 return 0;
 357         return ext4_inode_block_valid(inode, block, len);
 358 }
 359
 360 static int ext4_valid_extent_idx(struct inode *inode,
 361                                 struct ext4_extent_idx *ext_idx)
 362 {
 363         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 364
 365         return ext4_inode_block_valid(inode, block, 1);
 366 }
 367
 368 static int ext4_valid_extent_entries(struct inode *inode,
 369                                      struct ext4_extent_header *eh,
 370                                      ext4_lblk_t lblk, ext4_fsblk_t *pblk,
 371                                      int depth)
 372 {
 373         unsigned short entries;
 374         ext4_lblk_t lblock = 0;
 375         ext4_lblk_t cur = 0;
 376
 377         if (eh->eh_entries == 0)
 378                 return 1;
 379
 380         entries = le16_to_cpu(eh->eh_entries);
 381
 382         if (depth == 0) {
 383                 /* leaf entries */
 384                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 385
 386                 /*
 387                  * The logical block in the first entry should equal to
 388                  * the number in the index block.
 389                  */
 390                 if (depth != ext_depth(inode) &&
 391                     lblk != le32_to_cpu(ext->ee_block))
 392                         return 0;
 393                 while (entries) {
 394                         if (!ext4_valid_extent(inode, ext))
 395                                 return 0;
 396
 397                         /* Check for overlapping extents */
 398                         lblock = le32_to_cpu(ext->ee_block);
 399                         if (lblock < cur) {
 400                                 *pblk = ext4_ext_pblock(ext);
 401                                 return 0;
 402                         }
 403                         cur = lblock + ext4_ext_get_actual_len(ext);
 404                         ext++;
 405                         entries--;
 406                 }
 407         } else {
 408                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 409
 410                 /*
 411                  * The logical block in the first entry should equal to
 412                  * the number in the parent index block.
 413                  */
 414                 if (depth != ext_depth(inode) &&
 415                     lblk != le32_to_cpu(ext_idx->ei_block))
 416                         return 0;
 417                 while (entries) {
 418                         if (!ext4_valid_extent_idx(inode, ext_idx))
 419                                 return 0;
 420
 421                         /* Check for overlapping index extents */
 422                         lblock = le32_to_cpu(ext_idx->ei_block);
 423                         if (lblock < cur) {
 424                                 *pblk = ext4_idx_pblock(ext_idx);
 425                                 return 0;
 426                         }
 427                         ext_idx++;
 428                         entries--;
 429                         cur = lblock + 1;
 430                 }
 431         }
 432         return 1;
 433 }
 434
 435 static int __ext4_ext_check(const char *function, unsigned int line,
 436                             struct inode *inode, struct ext4_extent_header *eh,
 437                             int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk)
 438 {
 439         const char *error_msg;
 440         int max = 0, err = -EFSCORRUPTED;
 441
 442         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 443                 error_msg = "invalid magic";
 444                 goto corrupted;
 445         }
 446         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 447                 error_msg = "unexpected eh_depth";
 448                 goto corrupted;
 449         }
 450         if (unlikely(eh->eh_max == 0)) {
 451                 error_msg = "invalid eh_max";
 452                 goto corrupted;
 453         }
 454         max = ext4_ext_max_entries(inode, depth);
 455         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 456                 error_msg = "too large eh_max";
 457                 goto corrupted;
 458         }
 459         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 460                 error_msg = "invalid eh_entries";
 461                 goto corrupted;
 462         }
 463         if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) {
 464                 error_msg = "invalid extent entries";
 465                 goto corrupted;
 466         }
 467         if (unlikely(depth > 32)) {
 468                 error_msg = "too large eh_depth";
 469                 goto corrupted;
 470         }
 471         /* Verify checksum on non-root extent tree nodes */
 472         if (ext_depth(inode) != depth &&
 473             !ext4_extent_block_csum_verify(inode, eh)) {
 474                 error_msg = "extent tree corrupted";
 475                 err = -EFSBADCRC;
 476                 goto corrupted;
 477         }
 478         return 0;
 479
 480 corrupted:
 481         ext4_error_inode_err(inode, function, line, 0, -err,
 482                              "pblk %llu bad header/extent: %s - magic %x, "
 483                              "entries %u, max %u(%u), depth %u(%u)",
 484                              (unsigned long long) pblk, error_msg,
 485                              le16_to_cpu(eh->eh_magic),
 486                              le16_to_cpu(eh->eh_entries),
 487                              le16_to_cpu(eh->eh_max),
 488                              max, le16_to_cpu(eh->eh_depth), depth);
 489         return err;
 490 }
 491
 492 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 493         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)
 494
 495 int ext4_ext_check_inode(struct inode *inode)
 496 {
 497         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 498 }
 499
 500 static void ext4_cache_extents(struct inode *inode,
 501                                struct ext4_extent_header *eh)
 502 {
 503         struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 504         ext4_lblk_t prev = 0;
 505         int i;
 506
 507         for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 508                 unsigned int status = EXTENT_STATUS_WRITTEN;
 509                 ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 510                 int len = ext4_ext_get_actual_len(ex);
 511
 512                 if (prev && (prev != lblk))
 513                         ext4_es_cache_extent(inode, prev, lblk - prev, ~0,
 514                                              EXTENT_STATUS_HOLE);
 515
 516                 if (ext4_ext_is_unwritten(ex))
 517                         status = EXTENT_STATUS_UNWRITTEN;
 518                 ext4_es_cache_extent(inode, lblk, len,
 519                                      ext4_ext_pblock(ex), status);
 520                 prev = lblk + len;
 521         }
 522 }
 523
 524 static struct buffer_head *
 525 __read_extent_tree_block(const char *function, unsigned int line,
 526                          struct inode *inode, struct ext4_extent_idx *idx,
 527                          int depth, int flags)
 528 {
 529         struct buffer_head              *bh;
 530         int                             err;
 531         gfp_t                           gfp_flags = __GFP_MOVABLE | GFP_NOFS;
 532         ext4_fsblk_t                    pblk;
 533
 534         if (flags & EXT4_EX_NOFAIL)
 535                 gfp_flags |= __GFP_NOFAIL;
 536
 537         pblk = ext4_idx_pblock(idx);
 538         bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);
 539         if (unlikely(!bh))
 540                 return ERR_PTR(-ENOMEM);
 541
 542         if (!bh_uptodate_or_lock(bh)) {
 543                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 544                 err = ext4_read_bh(bh, 0, NULL);
 545                 if (err < 0)
 546                         goto errout;
 547         }
 548         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 549                 return bh;
 550         err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh),
 551                                depth, pblk, le32_to_cpu(idx->ei_block));
 552         if (err)
 553                 goto errout;
 554         set_buffer_verified(bh);
 555         /*
 556          * If this is a leaf block, cache all of its entries
 557          */
 558         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 559                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 560                 ext4_cache_extents(inode, eh);
 561         }
 562         return bh;
 563 errout:
 564         put_bh(bh);
 565         return ERR_PTR(err);
 566
 567 }
 568
 569 #define read_extent_tree_block(inode, idx, depth, flags)                \
 570         __read_extent_tree_block(__func__, __LINE__, (inode), (idx),    \
 571                                  (depth), (flags))
 572
 573 /*
 574  * This function is called to cache a file's extent information in the
 575  * extent status tree
 576  */
 577 int ext4_ext_precache(struct inode *inode)
 578 {
 579         struct ext4_inode_info *ei = EXT4_I(inode);
 580         struct ext4_ext_path *path = NULL;
 581         struct buffer_head *bh;
 582         int i = 0, depth, ret = 0;
 583
 584         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 585                 return 0;       /* not an extent-mapped inode */
 586
 587         down_read(&ei->i_data_sem);
 588         depth = ext_depth(inode);
 589
 590         /* Don't cache anything if there are no external extent blocks */
 591         if (!depth) {
 592                 up_read(&ei->i_data_sem);
 593                 return ret;
 594         }
 595
 596         path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
 597                        GFP_NOFS);
 598         if (path == NULL) {
 599                 up_read(&ei->i_data_sem);
 600                 return -ENOMEM;
 601         }
 602
 603         path[0].p_hdr = ext_inode_hdr(inode);
 604         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 605         if (ret)
 606                 goto out;
 607         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 608         while (i >= 0) {
 609                 /*
 610                  * If this is a leaf block or we've reached the end of
 611                  * the index block, go up
 612                  */
 613                 if ((i == depth) ||
 614                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 615                         brelse(path[i].p_bh);
 616                         path[i].p_bh = NULL;
 617                         i--;
 618                         continue;
 619                 }
 620                 bh = read_extent_tree_block(inode, path[i].p_idx++,
 621                                             depth - i - 1,
 622                                             EXT4_EX_FORCE_CACHE);
 623                 if (IS_ERR(bh)) {
 624                         ret = PTR_ERR(bh);
 625                         break;
 626                 }
 627                 i++;
 628                 path[i].p_bh = bh;
 629                 path[i].p_hdr = ext_block_hdr(bh);
 630                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 631         }
 632         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 633 out:
 634         up_read(&ei->i_data_sem);
 635         ext4_ext_drop_refs(path);
 636         kfree(path);
 637         return ret;
 638 }
 639
 640 #ifdef EXT_DEBUG
 641 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 642 {
 643         int k, l = path->p_depth;
 644
 645         ext_debug(inode, "path:");
 646         for (k = 0; k <= l; k++, path++) {
 647                 if (path->p_idx) {
 648                         ext_debug(inode, "  %d->%llu",
 649                                   le32_to_cpu(path->p_idx->ei_block),
 650                                   ext4_idx_pblock(path->p_idx));
 651                 } else if (path->p_ext) {
 652                         ext_debug(inode, "  %d:[%d]%d:%llu ",
 653                                   le32_to_cpu(path->p_ext->ee_block),
 654                                   ext4_ext_is_unwritten(path->p_ext),
 655                                   ext4_ext_get_actual_len(path->p_ext),
 656                                   ext4_ext_pblock(path->p_ext));
 657                 } else
 658                         ext_debug(inode, "  []");
 659         }
 660         ext_debug(inode, "\n");
 661 }
 662
 663 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 664 {
 665         int depth = ext_depth(inode);
 666         struct ext4_extent_header *eh;
 667         struct ext4_extent *ex;
 668         int i;
 669
 670         if (!path)
 671                 return;
 672
 673         eh = path[depth].p_hdr;
 674         ex = EXT_FIRST_EXTENT(eh);
 675
 676         ext_debug(inode, "Displaying leaf extents\n");
 677
 678         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 679                 ext_debug(inode, "%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 680                           ext4_ext_is_unwritten(ex),
 681                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 682         }
 683         ext_debug(inode, "\n");
 684 }
 685
 686 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 687                         ext4_fsblk_t newblock, int level)
 688 {
 689         int depth = ext_depth(inode);
 690         struct ext4_extent *ex;
 691
 692         if (depth != level) {
 693                 struct ext4_extent_idx *idx;
 694                 idx = path[level].p_idx;
 695                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 696                         ext_debug(inode, "%d: move %d:%llu in new index %llu\n",
 697                                   level, le32_to_cpu(idx->ei_block),
 698                                   ext4_idx_pblock(idx), newblock);
 699                         idx++;
 700                 }
 701
 702                 return;
 703         }
 704
 705         ex = path[depth].p_ext;
 706         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 707                 ext_debug(inode, "move %d:%llu:[%d]%d in new leaf %llu\n",
 708                                 le32_to_cpu(ex->ee_block),
 709                                 ext4_ext_pblock(ex),
 710                                 ext4_ext_is_unwritten(ex),
 711                                 ext4_ext_get_actual_len(ex),
 712                                 newblock);
 713                 ex++;
 714         }
 715 }
 716
 717 #else
 718 #define ext4_ext_show_path(inode, path)
 719 #define ext4_ext_show_leaf(inode, path)
 720 #define ext4_ext_show_move(inode, path, newblock, level)
 721 #endif
 722
 723 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 724 {
 725         int depth, i;
 726
 727         if (!path)
 728                 return;
 729         depth = path->p_depth;
 730         for (i = 0; i <= depth; i++, path++) {
 731                 brelse(path->p_bh);
 732                 path->p_bh = NULL;
 733         }
 734 }
 735
 736 /*
 737  * ext4_ext_binsearch_idx:
 738  * binary search for the closest index of the given block
 739  * the header must be checked before calling this
 740  */
 741 static void
 742 ext4_ext_binsearch_idx(struct inode *inode,
 743                         struct ext4_ext_path *path, ext4_lblk_t block)
 744 {
 745         struct ext4_extent_header *eh = path->p_hdr;
 746         struct ext4_extent_idx *r, *l, *m;
 747
 748
 749         ext_debug(inode, "binsearch for %u(idx):  ", block);
 750
 751         l = EXT_FIRST_INDEX(eh) + 1;
 752         r = EXT_LAST_INDEX(eh);
 753         while (l <= r) {
 754                 m = l + (r - l) / 2;
 755                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 756                           le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block),
 757                           r, le32_to_cpu(r->ei_block));
 758
 759                 if (block < le32_to_cpu(m->ei_block))
 760                         r = m - 1;
 761                 else
 762                         l = m + 1;
 763         }
 764
 765         path->p_idx = l - 1;
 766         ext_debug(inode, "  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 767                   ext4_idx_pblock(path->p_idx));
 768
 769 #ifdef CHECK_BINSEARCH
 770         {
 771                 struct ext4_extent_idx *chix, *ix;
 772                 int k;
 773
 774                 chix = ix = EXT_FIRST_INDEX(eh);
 775                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 776                         if (k != 0 && le32_to_cpu(ix->ei_block) <=
 777                             le32_to_cpu(ix[-1].ei_block)) {
 778                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 779                                        "first=0x%p\n", k,
 780                                        ix, EXT_FIRST_INDEX(eh));
 781                                 printk(KERN_DEBUG "%u <= %u\n",
 782                                        le32_to_cpu(ix->ei_block),
 783                                        le32_to_cpu(ix[-1].ei_block));
 784                         }
 785                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 786                                            <= le32_to_cpu(ix[-1].ei_block));
 787                         if (block < le32_to_cpu(ix->ei_block))
 788                                 break;
 789                         chix = ix;
 790                 }
 791                 BUG_ON(chix != path->p_idx);
 792         }
 793 #endif
 794
 795 }
 796
 797 /*
 798  * ext4_ext_binsearch:
 799  * binary search for closest extent of the given block
 800  * the header must be checked before calling this
 801  */
 802 static void
 803 ext4_ext_binsearch(struct inode *inode,
 804                 struct ext4_ext_path *path, ext4_lblk_t block)
 805 {
 806         struct ext4_extent_header *eh = path->p_hdr;
 807         struct ext4_extent *r, *l, *m;
 808
 809         if (eh->eh_entries == 0) {
 810                 /*
 811                  * this leaf is empty:
 812                  * we get such a leaf in split/add case
 813                  */
 814                 return;
 815         }
 816
 817         ext_debug(inode, "binsearch for %u:  ", block);
 818
 819         l = EXT_FIRST_EXTENT(eh) + 1;
 820         r = EXT_LAST_EXTENT(eh);
 821
 822         while (l <= r) {
 823                 m = l + (r - l) / 2;
 824                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 825                           le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block),
 826                           r, le32_to_cpu(r->ee_block));
 827
 828                 if (block < le32_to_cpu(m->ee_block))
 829                         r = m - 1;
 830                 else
 831                         l = m + 1;
 832         }
 833
 834         path->p_ext = l - 1;
 835         ext_debug(inode, "  -> %d:%llu:[%d]%d ",
 836                         le32_to_cpu(path->p_ext->ee_block),
 837                         ext4_ext_pblock(path->p_ext),
 838                         ext4_ext_is_unwritten(path->p_ext),
 839                         ext4_ext_get_actual_len(path->p_ext));
 840
 841 #ifdef CHECK_BINSEARCH
 842         {
 843                 struct ext4_extent *chex, *ex;
 844                 int k;
 845
 846                 chex = ex = EXT_FIRST_EXTENT(eh);
 847                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 848                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 849                                           <= le32_to_cpu(ex[-1].ee_block));
 850                         if (block < le32_to_cpu(ex->ee_block))
 851                                 break;
 852                         chex = ex;
 853                 }
 854                 BUG_ON(chex != path->p_ext);
 855         }
 856 #endif
 857
 858 }
 859
 860 void ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 861 {
 862         struct ext4_extent_header *eh;
 863
 864         eh = ext_inode_hdr(inode);
 865         eh->eh_depth = 0;
 866         eh->eh_entries = 0;
 867         eh->eh_magic = EXT4_EXT_MAGIC;
 868         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 869         eh->eh_generation = 0;
 870         ext4_mark_inode_dirty(handle, inode);
 871 }
 872
 873 struct ext4_ext_path *
 874 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 875                  struct ext4_ext_path **orig_path, int flags)
 876 {
 877         struct ext4_extent_header *eh;
 878         struct buffer_head *bh;
 879         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 880         short int depth, i, ppos = 0;
 881         int ret;
 882         gfp_t gfp_flags = GFP_NOFS;
 883
 884         if (flags & EXT4_EX_NOFAIL)
 885                 gfp_flags |= __GFP_NOFAIL;
 886
 887         eh = ext_inode_hdr(inode);
 888         depth = ext_depth(inode);
 889         if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
 890                 EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
 891                                  depth);
 892                 ret = -EFSCORRUPTED;
 893                 goto err;
 894         }
 895
 896         if (path) {
 897                 ext4_ext_drop_refs(path);
 898                 if (depth > path[0].p_maxdepth) {
 899                         kfree(path);
 900                         *orig_path = path = NULL;
 901                 }
 902         }
 903         if (!path) {
 904                 /* account possible depth increase */
 905                 path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
 906                                 gfp_flags);
 907                 if (unlikely(!path))
 908                         return ERR_PTR(-ENOMEM);
 909                 path[0].p_maxdepth = depth + 1;
 910         }
 911         path[0].p_hdr = eh;
 912         path[0].p_bh = NULL;
 913
 914         i = depth;
 915         if (!(flags & EXT4_EX_NOCACHE) && depth == 0)
 916                 ext4_cache_extents(inode, eh);
 917         /* walk through the tree */
 918         while (i) {
 919                 ext_debug(inode, "depth %d: num %d, max %d\n",
 920                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 921
 922                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 923                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 924                 path[ppos].p_depth = i;
 925                 path[ppos].p_ext = NULL;
 926
 927                 bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);
 928                 if (IS_ERR(bh)) {
 929                         ret = PTR_ERR(bh);
 930                         goto err;
 931                 }
 932
 933                 eh = ext_block_hdr(bh);
 934                 ppos++;
 935                 path[ppos].p_bh = bh;
 936                 path[ppos].p_hdr = eh;
 937         }
 938
 939         path[ppos].p_depth = i;
 940         path[ppos].p_ext = NULL;
 941         path[ppos].p_idx = NULL;
 942
 943         /* find extent */
 944         ext4_ext_binsearch(inode, path + ppos, block);
 945         /* if not an empty leaf */
 946         if (path[ppos].p_ext)
 947                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 948
 949         ext4_ext_show_path(inode, path);
 950
 951         return path;
 952
 953 err:
 954         ext4_ext_drop_refs(path);
 955         kfree(path);
 956         if (orig_path)
 957                 *orig_path = NULL;
 958         return ERR_PTR(ret);
 959 }
 960
 961 /*
 962  * ext4_ext_insert_index:
 963  * insert new index [@logical;@ptr] into the block at @curp;
 964  * check where to insert: before @curp or after @curp
 965  */
 966 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 967                                  struct ext4_ext_path *curp,
 968                                  int logical, ext4_fsblk_t ptr)
 969 {
 970         struct ext4_extent_idx *ix;
 971         int len, err;
 972
 973         err = ext4_ext_get_access(handle, inode, curp);
 974         if (err)
 975                 return err;
 976
 977         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 978                 EXT4_ERROR_INODE(inode,
 979                                  "logical %d == ei_block %d!",
 980                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 981                 return -EFSCORRUPTED;
 982         }
 983
 984         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 985                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 986                 EXT4_ERROR_INODE(inode,
 987                                  "eh_entries %d >= eh_max %d!",
 988                                  le16_to_cpu(curp->p_hdr->eh_entries),
 989                                  le16_to_cpu(curp->p_hdr->eh_max));
 990                 return -EFSCORRUPTED;
 991         }
 992
 993         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 994                 /* insert after */
 995                 ext_debug(inode, "insert new index %d after: %llu\n",
 996                           logical, ptr);
 997                 ix = curp->p_idx + 1;
 998         } else {
 999                 /* insert before */
1000                 ext_debug(inode, "insert new index %d before: %llu\n",
1001                           logical, ptr);
1002                 ix = curp->p_idx;
1003         }
1004
1005         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
1006         BUG_ON(len < 0);
1007         if (len > 0) {
1008                 ext_debug(inode, "insert new index %d: "
1009                                 "move %d indices from 0x%p to 0x%p\n",
1010                                 logical, len, ix, ix + 1);
1011                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
1012         }
1013
1014         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
1015                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1016                 return -EFSCORRUPTED;
1017         }
1018
1019         ix->ei_block = cpu_to_le32(logical);
1020         ext4_idx_store_pblock(ix, ptr);
1021         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1022
1023         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1024                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1025                 return -EFSCORRUPTED;
1026         }
1027
1028         err = ext4_ext_dirty(handle, inode, curp);
1029         ext4_std_error(inode->i_sb, err);
1030
1031         return err;
1032 }
1033
1034 /*
1035  * ext4_ext_split:
1036  * inserts new subtree into the path, using free index entry
1037  * at depth @at:
1038  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1039  * - makes decision where to split
1040  * - moves remaining extents and index entries (right to the split point)
1041  *   into the newly allocated blocks
1042  * - initializes subtree
1043  */
1044 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1045                           unsigned int flags,
1046                           struct ext4_ext_path *path,
1047                           struct ext4_extent *newext, int at)
1048 {
1049         struct buffer_head *bh = NULL;
1050         int depth = ext_depth(inode);
1051         struct ext4_extent_header *neh;
1052         struct ext4_extent_idx *fidx;
1053         int i = at, k, m, a;
1054         ext4_fsblk_t newblock, oldblock;
1055         __le32 border;
1056         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1057         gfp_t gfp_flags = GFP_NOFS;
1058         int err = 0;
1059         size_t ext_size = 0;
1060
1061         if (flags & EXT4_EX_NOFAIL)
1062                 gfp_flags |= __GFP_NOFAIL;
1063
1064         /* make decision: where to split? */
1065         /* FIXME: now decision is simplest: at current extent */
1066
1067         /* if current leaf will be split, then we should use
1068          * border from split point */
1069         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1070                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1071                 return -EFSCORRUPTED;
1072         }
1073         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1074                 border = path[depth].p_ext[1].ee_block;
1075                 ext_debug(inode, "leaf will be split."
1076                                 " next leaf starts at %d\n",
1077                                   le32_to_cpu(border));
1078         } else {
1079                 border = newext->ee_block;
1080                 ext_debug(inode, "leaf will be added."
1081                                 " next leaf starts at %d\n",
1082                                 le32_to_cpu(border));
1083         }
1084
1085         /*
1086          * If error occurs, then we break processing
1087          * and mark filesystem read-only. index won't
1088          * be inserted and tree will be in consistent
1089          * state. Next mount will repair buffers too.
1090          */
1091
1092         /*
1093          * Get array to track all allocated blocks.
1094          * We need this to handle errors and free blocks
1095          * upon them.
1096          */
1097         ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), gfp_flags);
1098         if (!ablocks)
1099                 return -ENOMEM;
1100
1101         /* allocate all needed blocks */
1102         ext_debug(inode, "allocate %d blocks for indexes/leaf\n", depth - at);
1103         for (a = 0; a < depth - at; a++) {
1104                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1105                                                    newext, &err, flags);
1106                 if (newblock == 0)
1107                         goto cleanup;
1108                 ablocks[a] = newblock;
1109         }
1110
1111         /* initialize new leaf */
1112         newblock = ablocks[--a];
1113         if (unlikely(newblock == 0)) {
1114                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1115                 err = -EFSCORRUPTED;
1116                 goto cleanup;
1117         }
1118         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1119         if (unlikely(!bh)) {
1120                 err = -ENOMEM;
1121                 goto cleanup;
1122         }
1123         lock_buffer(bh);
1124
1125         err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1126                                              EXT4_JTR_NONE);
1127         if (err)
1128                 goto cleanup;
1129
1130         neh = ext_block_hdr(bh);
1131         neh->eh_entries = 0;
1132         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1133         neh->eh_magic = EXT4_EXT_MAGIC;
1134         neh->eh_depth = 0;
1135         neh->eh_generation = 0;
1136
1137         /* move remainder of path[depth] to the new leaf */
1138         if (unlikely(path[depth].p_hdr->eh_entries !=
1139                      path[depth].p_hdr->eh_max)) {
1140                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1141                                  path[depth].p_hdr->eh_entries,
1142                                  path[depth].p_hdr->eh_max);
1143                 err = -EFSCORRUPTED;
1144                 goto cleanup;
1145         }
1146         /* start copy from next extent */
1147         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1148         ext4_ext_show_move(inode, path, newblock, depth);
1149         if (m) {
1150                 struct ext4_extent *ex;
1151                 ex = EXT_FIRST_EXTENT(neh);
1152                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1153                 le16_add_cpu(&neh->eh_entries, m);
1154         }
1155
1156         /* zero out unused area in the extent block */
1157         ext_size = sizeof(struct ext4_extent_header) +
1158                 sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries);
1159         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1160         ext4_extent_block_csum_set(inode, neh);
1161         set_buffer_uptodate(bh);
1162         unlock_buffer(bh);
1163
1164         err = ext4_handle_dirty_metadata(handle, inode, bh);
1165         if (err)
1166                 goto cleanup;
1167         brelse(bh);
1168         bh = NULL;
1169
1170         /* correct old leaf */
1171         if (m) {
1172                 err = ext4_ext_get_access(handle, inode, path + depth);
1173                 if (err)
1174                         goto cleanup;
1175                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1176                 err = ext4_ext_dirty(handle, inode, path + depth);
1177                 if (err)
1178                         goto cleanup;
1179
1180         }
1181
1182         /* create intermediate indexes */
1183         k = depth - at - 1;
1184         if (unlikely(k < 0)) {
1185                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1186                 err = -EFSCORRUPTED;
1187                 goto cleanup;
1188         }
1189         if (k)
1190                 ext_debug(inode, "create %d intermediate indices\n", k);
1191         /* insert new index into current index block */
1192         /* current depth stored in i var */
1193         i = depth - 1;
1194         while (k--) {
1195                 oldblock = newblock;
1196                 newblock = ablocks[--a];
1197                 bh = sb_getblk(inode->i_sb, newblock);
1198                 if (unlikely(!bh)) {
1199                         err = -ENOMEM;
1200                         goto cleanup;
1201                 }
1202                 lock_buffer(bh);
1203
1204                 err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1205                                                      EXT4_JTR_NONE);
1206                 if (err)
1207                         goto cleanup;
1208
1209                 neh = ext_block_hdr(bh);
1210                 neh->eh_entries = cpu_to_le16(1);
1211                 neh->eh_magic = EXT4_EXT_MAGIC;
1212                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1213                 neh->eh_depth = cpu_to_le16(depth - i);
1214                 neh->eh_generation = 0;
1215                 fidx = EXT_FIRST_INDEX(neh);
1216                 fidx->ei_block = border;
1217                 ext4_idx_store_pblock(fidx, oldblock);
1218
1219                 ext_debug(inode, "int.index at %d (block %llu): %u -> %llu\n",
1220                                 i, newblock, le32_to_cpu(border), oldblock);
1221
1222                 /* move remainder of path[i] to the new index block */
1223                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1224                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1225                         EXT4_ERROR_INODE(inode,
1226                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1227                                          le32_to_cpu(path[i].p_ext->ee_block));
1228                         err = -EFSCORRUPTED;
1229                         goto cleanup;
1230                 }
1231                 /* start copy indexes */
1232                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1233                 ext_debug(inode, "cur 0x%p, last 0x%p\n", path[i].p_idx,
1234                                 EXT_MAX_INDEX(path[i].p_hdr));
1235                 ext4_ext_show_move(inode, path, newblock, i);
1236                 if (m) {
1237                         memmove(++fidx, path[i].p_idx,
1238                                 sizeof(struct ext4_extent_idx) * m);
1239                         le16_add_cpu(&neh->eh_entries, m);
1240                 }
1241                 /* zero out unused area in the extent block */
1242                 ext_size = sizeof(struct ext4_extent_header) +
1243                    (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));
1244                 memset(bh->b_data + ext_size, 0,
1245                         inode->i_sb->s_blocksize - ext_size);
1246                 ext4_extent_block_csum_set(inode, neh);
1247                 set_buffer_uptodate(bh);
1248                 unlock_buffer(bh);
1249
1250                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1251                 if (err)
1252                         goto cleanup;
1253                 brelse(bh);
1254                 bh = NULL;
1255
1256                 /* correct old index */
1257                 if (m) {
1258                         err = ext4_ext_get_access(handle, inode, path + i);
1259                         if (err)
1260                                 goto cleanup;
1261                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1262                         err = ext4_ext_dirty(handle, inode, path + i);
1263                         if (err)
1264                                 goto cleanup;
1265                 }
1266
1267                 i--;
1268         }
1269
1270         /* insert new index */
1271         err = ext4_ext_insert_index(handle, inode, path + at,
1272                                     le32_to_cpu(border), newblock);
1273
1274 cleanup:
1275         if (bh) {
1276                 if (buffer_locked(bh))
1277                         unlock_buffer(bh);
1278                 brelse(bh);
1279         }
1280
1281         if (err) {
1282                 /* free all allocated blocks in error case */
1283                 for (i = 0; i < depth; i++) {
1284                         if (!ablocks[i])
1285                                 continue;
1286                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1287                                          EXT4_FREE_BLOCKS_METADATA);
1288                 }
1289         }
1290         kfree(ablocks);
1291
1292         return err;
1293 }
1294
1295 /*
1296  * ext4_ext_grow_indepth:
1297  * implements tree growing procedure:
1298  * - allocates new block
1299  * - moves top-level data (index block or leaf) into the new block
1300  * - initializes new top-level, creating index that points to the
1301  *   just created block
1302  */
1303 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1304                                  unsigned int flags)
1305 {
1306         struct ext4_extent_header *neh;
1307         struct buffer_head *bh;
1308         ext4_fsblk_t newblock, goal = 0;
1309         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1310         int err = 0;
1311         size_t ext_size = 0;
1312
1313         /* Try to prepend new index to old one */
1314         if (ext_depth(inode))
1315                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1316         if (goal > le32_to_cpu(es->s_first_data_block)) {
1317                 flags |= EXT4_MB_HINT_TRY_GOAL;
1318                 goal--;
1319         } else
1320                 goal = ext4_inode_to_goal_block(inode);
1321         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1322                                         NULL, &err);
1323         if (newblock == 0)
1324                 return err;
1325
1326         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1327         if (unlikely(!bh))
1328                 return -ENOMEM;
1329         lock_buffer(bh);
1330
1331         err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1332                                              EXT4_JTR_NONE);
1333         if (err) {
1334                 unlock_buffer(bh);
1335                 goto out;
1336         }
1337
1338         ext_size = sizeof(EXT4_I(inode)->i_data);
1339         /* move top-level index/leaf into new block */
1340         memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);
1341         /* zero out unused area in the extent block */
1342         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1343
1344         /* set size of new block */
1345         neh = ext_block_hdr(bh);
1346         /* old root could have indexes or leaves
1347          * so calculate e_max right way */
1348         if (ext_depth(inode))
1349                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1350         else
1351                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1352         neh->eh_magic = EXT4_EXT_MAGIC;
1353         ext4_extent_block_csum_set(inode, neh);
1354         set_buffer_uptodate(bh);
1355         set_buffer_verified(bh);
1356         unlock_buffer(bh);
1357
1358         err = ext4_handle_dirty_metadata(handle, inode, bh);
1359         if (err)
1360                 goto out;
1361
1362         /* Update top-level index: num,max,pointer */
1363         neh = ext_inode_hdr(inode);
1364         neh->eh_entries = cpu_to_le16(1);
1365         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1366         if (neh->eh_depth == 0) {
1367                 /* Root extent block becomes index block */
1368                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1369                 EXT_FIRST_INDEX(neh)->ei_block =
1370                         EXT_FIRST_EXTENT(neh)->ee_block;
1371         }
1372         ext_debug(inode, "new root: num %d(%d), lblock %d, ptr %llu\n",
1373                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1374                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1375                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1376
1377         le16_add_cpu(&neh->eh_depth, 1);
1378         err = ext4_mark_inode_dirty(handle, inode);
1379 out:
1380         brelse(bh);
1381
1382         return err;
1383 }
1384
1385 /*
1386  * ext4_ext_create_new_leaf:
1387  * finds empty index and adds new leaf.
1388  * if no free index is found, then it requests in-depth growing.
1389  */
1390 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1391                                     unsigned int mb_flags,
1392                                     unsigned int gb_flags,
1393                                     struct ext4_ext_path **ppath,
1394                                     struct ext4_extent *newext)
1395 {
1396         struct ext4_ext_path *path = *ppath;
1397         struct ext4_ext_path *curp;
1398         int depth, i, err = 0;
1399
1400 repeat:
1401         i = depth = ext_depth(inode);
1402
1403         /* walk up to the tree and look for free index entry */
1404         curp = path + depth;
1405         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1406                 i--;
1407                 curp--;
1408         }
1409
1410         /* we use already allocated block for index block,
1411          * so subsequent data blocks should be contiguous */
1412         if (EXT_HAS_FREE_INDEX(curp)) {
1413                 /* if we found index with free entry, then use that
1414                  * entry: create all needed subtree and add new leaf */
1415                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1416                 if (err)
1417                         goto out;
1418
1419                 /* refill path */
1420                 path = ext4_find_extent(inode,
1421                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1422                                     ppath, gb_flags);
1423                 if (IS_ERR(path))
1424                         err = PTR_ERR(path);
1425         } else {
1426                 /* tree is full, time to grow in depth */
1427                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1428                 if (err)
1429                         goto out;
1430
1431                 /* refill path */
1432                 path = ext4_find_extent(inode,
1433                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1434                                     ppath, gb_flags);
1435                 if (IS_ERR(path)) {
1436                         err = PTR_ERR(path);
1437                         goto out;
1438                 }
1439
1440                 /*
1441                  * only first (depth 0 -> 1) produces free space;
1442                  * in all other cases we have to split the grown tree
1443                  */
1444                 depth = ext_depth(inode);
1445                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1446                         /* now we need to split */
1447                         goto repeat;
1448                 }
1449         }
1450
1451 out:
1452         return err;
1453 }
1454
1455 /*
1456  * search the closest allocated block to the left for *logical
1457  * and returns it at @logical + it's physical address at @phys
1458  * if *logical is the smallest allocated block, the function
1459  * returns 0 at @phys
1460  * return value contains 0 (success) or error code
1461  */
1462 static int ext4_ext_search_left(struct inode *inode,
1463                                 struct ext4_ext_path *path,
1464                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1465 {
1466         struct ext4_extent_idx *ix;
1467         struct ext4_extent *ex;
1468         int depth, ee_len;
1469
1470         if (unlikely(path == NULL)) {
1471                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1472                 return -EFSCORRUPTED;
1473         }
1474         depth = path->p_depth;
1475         *phys = 0;
1476
1477         if (depth == 0 && path->p_ext == NULL)
1478                 return 0;
1479
1480         /* usually extent in the path covers blocks smaller
1481          * then *logical, but it can be that extent is the
1482          * first one in the file */
1483
1484         ex = path[depth].p_ext;
1485         ee_len = ext4_ext_get_actual_len(ex);
1486         if (*logical < le32_to_cpu(ex->ee_block)) {
1487                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1488                         EXT4_ERROR_INODE(inode,
1489                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1490                                          *logical, le32_to_cpu(ex->ee_block));
1491                         return -EFSCORRUPTED;
1492                 }
1493                 while (--depth >= 0) {
1494                         ix = path[depth].p_idx;
1495                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1496                                 EXT4_ERROR_INODE(inode,
1497                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1498                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1499                                   le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block),
1500                                   depth);
1501                                 return -EFSCORRUPTED;
1502                         }
1503                 }
1504                 return 0;
1505         }
1506
1507         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1508                 EXT4_ERROR_INODE(inode,
1509                                  "logical %d < ee_block %d + ee_len %d!",
1510                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1511                 return -EFSCORRUPTED;
1512         }
1513
1514         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1515         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1516         return 0;
1517 }
1518
1519 /*
1520  * Search the closest allocated block to the right for *logical
1521  * and returns it at @logical + it's physical address at @phys.
1522  * If not exists, return 0 and @phys is set to 0. We will return
1523  * 1 which means we found an allocated block and ret_ex is valid.
1524  * Or return a (< 0) error code.
1525  */
1526 static int ext4_ext_search_right(struct inode *inode,
1527                                  struct ext4_ext_path *path,
1528                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1529                                  struct ext4_extent *ret_ex)
1530 {
1531         struct buffer_head *bh = NULL;
1532         struct ext4_extent_header *eh;
1533         struct ext4_extent_idx *ix;
1534         struct ext4_extent *ex;
1535         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1536         int ee_len;
1537
1538         if (unlikely(path == NULL)) {
1539                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1540                 return -EFSCORRUPTED;
1541         }
1542         depth = path->p_depth;
1543         *phys = 0;
1544
1545         if (depth == 0 && path->p_ext == NULL)
1546                 return 0;
1547
1548         /* usually extent in the path covers blocks smaller
1549          * then *logical, but it can be that extent is the
1550          * first one in the file */
1551
1552         ex = path[depth].p_ext;
1553         ee_len = ext4_ext_get_actual_len(ex);
1554         if (*logical < le32_to_cpu(ex->ee_block)) {
1555                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1556                         EXT4_ERROR_INODE(inode,
1557                                          "first_extent(path[%d].p_hdr) != ex",
1558                                          depth);
1559                         return -EFSCORRUPTED;
1560                 }
1561                 while (--depth >= 0) {
1562                         ix = path[depth].p_idx;
1563                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1564                                 EXT4_ERROR_INODE(inode,
1565                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1566                                                  *logical);
1567                                 return -EFSCORRUPTED;
1568                         }
1569                 }
1570                 goto found_extent;
1571         }
1572
1573         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1574                 EXT4_ERROR_INODE(inode,
1575                                  "logical %d < ee_block %d + ee_len %d!",
1576                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1577                 return -EFSCORRUPTED;
1578         }
1579
1580         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1581                 /* next allocated block in this leaf */
1582                 ex++;
1583                 goto found_extent;
1584         }
1585
1586         /* go up and search for index to the right */
1587         while (--depth >= 0) {
1588                 ix = path[depth].p_idx;
1589                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1590                         goto got_index;
1591         }
1592
1593         /* we've gone up to the root and found no index to the right */
1594         return 0;
1595
1596 got_index:
1597         /* we've found index to the right, let's
1598          * follow it and find the closest allocated
1599          * block to the right */
1600         ix++;
1601         while (++depth < path->p_depth) {
1602                 /* subtract from p_depth to get proper eh_depth */
1603                 bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
1604                 if (IS_ERR(bh))
1605                         return PTR_ERR(bh);
1606                 eh = ext_block_hdr(bh);
1607                 ix = EXT_FIRST_INDEX(eh);
1608                 put_bh(bh);
1609         }
1610
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         ex = EXT_FIRST_EXTENT(eh);
1616 found_extent:
1617         *logical = le32_to_cpu(ex->ee_block);
1618         *phys = ext4_ext_pblock(ex);
1619         if (ret_ex)
1620                 *ret_ex = *ex;
1621         if (bh)
1622                 put_bh(bh);
1623         return 1;
1624 }
1625
1626 /*
1627  * ext4_ext_next_allocated_block:
1628  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1629  * NOTE: it considers block number from index entry as
1630  * allocated block. Thus, index entries have to be consistent
1631  * with leaves.
1632  */
1633 ext4_lblk_t
1634 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1635 {
1636         int depth;
1637
1638         BUG_ON(path == NULL);
1639         depth = path->p_depth;
1640
1641         if (depth == 0 && path->p_ext == NULL)
1642                 return EXT_MAX_BLOCKS;
1643
1644         while (depth >= 0) {
1645                 struct ext4_ext_path *p = &path[depth];
1646
1647                 if (depth == path->p_depth) {
1648                         /* leaf */
1649                         if (p->p_ext && p->p_ext != EXT_LAST_EXTENT(p->p_hdr))
1650                                 return le32_to_cpu(p->p_ext[1].ee_block);
1651                 } else {
1652                         /* index */
1653                         if (p->p_idx != EXT_LAST_INDEX(p->p_hdr))
1654                                 return le32_to_cpu(p->p_idx[1].ei_block);
1655                 }
1656                 depth--;
1657         }
1658
1659         return EXT_MAX_BLOCKS;
1660 }
1661
1662 /*
1663  * ext4_ext_next_leaf_block:
1664  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1665  */
1666 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1667 {
1668         int depth;
1669
1670         BUG_ON(path == NULL);
1671         depth = path->p_depth;
1672
1673         /* zero-tree has no leaf blocks at all */
1674         if (depth == 0)
1675                 return EXT_MAX_BLOCKS;
1676
1677         /* go to index block */
1678         depth--;
1679
1680         while (depth >= 0) {
1681                 if (path[depth].p_idx !=
1682                                 EXT_LAST_INDEX(path[depth].p_hdr))
1683                         return (ext4_lblk_t)
1684                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1685                 depth--;
1686         }
1687
1688         return EXT_MAX_BLOCKS;
1689 }
1690
1691 /*
1692  * ext4_ext_correct_indexes:
1693  * if leaf gets modified and modified extent is first in the leaf,
1694  * then we have to correct all indexes above.
1695  * TODO: do we need to correct tree in all cases?
1696  */
1697 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1698                                 struct ext4_ext_path *path)
1699 {
1700         struct ext4_extent_header *eh;
1701         int depth = ext_depth(inode);
1702         struct ext4_extent *ex;
1703         __le32 border;
1704         int k, err = 0;
1705
1706         eh = path[depth].p_hdr;
1707         ex = path[depth].p_ext;
1708
1709         if (unlikely(ex == NULL || eh == NULL)) {
1710                 EXT4_ERROR_INODE(inode,
1711                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1712                 return -EFSCORRUPTED;
1713         }
1714
1715         if (depth == 0) {
1716                 /* there is no tree at all */
1717                 return 0;
1718         }
1719
1720         if (ex != EXT_FIRST_EXTENT(eh)) {
1721                 /* we correct tree if first leaf got modified only */
1722                 return 0;
1723         }
1724
1725         /*
1726          * TODO: we need correction if border is smaller than current one
1727          */
1728         k = depth - 1;
1729         border = path[depth].p_ext->ee_block;
1730         err = ext4_ext_get_access(handle, inode, path + k);
1731         if (err)
1732                 return err;
1733         path[k].p_idx->ei_block = border;
1734         err = ext4_ext_dirty(handle, inode, path + k);
1735         if (err)
1736                 return err;
1737
1738         while (k--) {
1739                 /* change all left-side indexes */
1740                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1741                         break;
1742                 err = ext4_ext_get_access(handle, inode, path + k);
1743                 if (err)
1744                         break;
1745                 path[k].p_idx->ei_block = border;
1746                 err = ext4_ext_dirty(handle, inode, path + k);
1747                 if (err)
1748                         break;
1749         }
1750
1751         return err;
1752 }
1753
1754 static int ext4_can_extents_be_merged(struct inode *inode,
1755                                       struct ext4_extent *ex1,
1756                                       struct ext4_extent *ex2)
1757 {
1758         unsigned short ext1_ee_len, ext2_ee_len;
1759
1760         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1761                 return 0;
1762
1763         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1764         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1765
1766         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1767                         le32_to_cpu(ex2->ee_block))
1768                 return 0;
1769
1770         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1771                 return 0;
1772
1773         if (ext4_ext_is_unwritten(ex1) &&
1774             ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)
1775                 return 0;
1776 #ifdef AGGRESSIVE_TEST
1777         if (ext1_ee_len >= 4)
1778                 return 0;
1779 #endif
1780
1781         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1782                 return 1;
1783         return 0;
1784 }
1785
1786 /*
1787  * This function tries to merge the "ex" extent to the next extent in the tree.
1788  * It always tries to merge towards right. If you want to merge towards
1789  * left, pass "ex - 1" as argument instead of "ex".
1790  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1791  * 1 if they got merged.
1792  */
1793 static int ext4_ext_try_to_merge_right(struct inode *inode,
1794                                  struct ext4_ext_path *path,
1795                                  struct ext4_extent *ex)
1796 {
1797         struct ext4_extent_header *eh;
1798         unsigned int depth, len;
1799         int merge_done = 0, unwritten;
1800
1801         depth = ext_depth(inode);
1802         BUG_ON(path[depth].p_hdr == NULL);
1803         eh = path[depth].p_hdr;
1804
1805         while (ex < EXT_LAST_EXTENT(eh)) {
1806                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1807                         break;
1808                 /* merge with next extent! */
1809                 unwritten = ext4_ext_is_unwritten(ex);
1810                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1811                                 + ext4_ext_get_actual_len(ex + 1));
1812                 if (unwritten)
1813                         ext4_ext_mark_unwritten(ex);
1814
1815                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1816                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1817                                 * sizeof(struct ext4_extent);
1818                         memmove(ex + 1, ex + 2, len);
1819                 }
1820                 le16_add_cpu(&eh->eh_entries, -1);
1821                 merge_done = 1;
1822                 WARN_ON(eh->eh_entries == 0);
1823                 if (!eh->eh_entries)
1824                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1825         }
1826
1827         return merge_done;
1828 }
1829
1830 /*
1831  * This function does a very simple check to see if we can collapse
1832  * an extent tree with a single extent tree leaf block into the inode.
1833  */
1834 static void ext4_ext_try_to_merge_up(handle_t *handle,
1835                                      struct inode *inode,
1836                                      struct ext4_ext_path *path)
1837 {
1838         size_t s;
1839         unsigned max_root = ext4_ext_space_root(inode, 0);
1840         ext4_fsblk_t blk;
1841
1842         if ((path[0].p_depth != 1) ||
1843             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1844             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1845                 return;
1846
1847         /*
1848          * We need to modify the block allocation bitmap and the block
1849          * group descriptor to release the extent tree block.  If we
1850          * can't get the journal credits, give up.
1851          */
1852         if (ext4_journal_extend(handle, 2,
1853                         ext4_free_metadata_revoke_credits(inode->i_sb, 1)))
1854                 return;
1855
1856         /*
1857          * Copy the extent data up to the inode
1858          */
1859         blk = ext4_idx_pblock(path[0].p_idx);
1860         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1861                 sizeof(struct ext4_extent_idx);
1862         s += sizeof(struct ext4_extent_header);
1863
1864         path[1].p_maxdepth = path[0].p_maxdepth;
1865         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1866         path[0].p_depth = 0;
1867         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1868                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1869         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1870
1871         brelse(path[1].p_bh);
1872         ext4_free_blocks(handle, inode, NULL, blk, 1,
1873                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1874 }
1875
1876 /*
1877  * This function tries to merge the @ex extent to neighbours in the tree, then
1878  * tries to collapse the extent tree into the inode.
1879  */
1880 static void ext4_ext_try_to_merge(handle_t *handle,
1881                                   struct inode *inode,
1882                                   struct ext4_ext_path *path,
1883                                   struct ext4_extent *ex)
1884 {
1885         struct ext4_extent_header *eh;
1886         unsigned int depth;
1887         int merge_done = 0;
1888
1889         depth = ext_depth(inode);
1890         BUG_ON(path[depth].p_hdr == NULL);
1891         eh = path[depth].p_hdr;
1892
1893         if (ex > EXT_FIRST_EXTENT(eh))
1894                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1895
1896         if (!merge_done)
1897                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1898
1899         ext4_ext_try_to_merge_up(handle, inode, path);
1900 }
1901
1902 /*
1903  * check if a portion of the "newext" extent overlaps with an
1904  * existing extent.
1905  *
1906  * If there is an overlap discovered, it updates the length of the newext
1907  * such that there will be no overlap, and then returns 1.
1908  * If there is no overlap found, it returns 0.
1909  */
1910 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1911                                            struct inode *inode,
1912                                            struct ext4_extent *newext,
1913                                            struct ext4_ext_path *path)
1914 {
1915         ext4_lblk_t b1, b2;
1916         unsigned int depth, len1;
1917         unsigned int ret = 0;
1918
1919         b1 = le32_to_cpu(newext->ee_block);
1920         len1 = ext4_ext_get_actual_len(newext);
1921         depth = ext_depth(inode);
1922         if (!path[depth].p_ext)
1923                 goto out;
1924         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1925
1926         /*
1927          * get the next allocated block if the extent in the path
1928          * is before the requested block(s)
1929          */
1930         if (b2 < b1) {
1931                 b2 = ext4_ext_next_allocated_block(path);
1932                 if (b2 == EXT_MAX_BLOCKS)
1933                         goto out;
1934                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1935         }
1936
1937         /* check for wrap through zero on extent logical start block*/
1938         if (b1 + len1 < b1) {
1939                 len1 = EXT_MAX_BLOCKS - b1;
1940                 newext->ee_len = cpu_to_le16(len1);
1941                 ret = 1;
1942         }
1943
1944         /* check for overlap */
1945         if (b1 + len1 > b2) {
1946                 newext->ee_len = cpu_to_le16(b2 - b1);
1947                 ret = 1;
1948         }
1949 out:
1950         return ret;
1951 }
1952
1953 /*
1954  * ext4_ext_insert_extent:
1955  * tries to merge requested extent into the existing extent or
1956  * inserts requested extent as new one into the tree,
1957  * creating new leaf in the no-space case.
1958  */
1959 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1960                                 struct ext4_ext_path **ppath,
1961                                 struct ext4_extent *newext, int gb_flags)
1962 {
1963         struct ext4_ext_path *path = *ppath;
1964         struct ext4_extent_header *eh;
1965         struct ext4_extent *ex, *fex;
1966         struct ext4_extent *nearex; /* nearest extent */
1967         struct ext4_ext_path *npath = NULL;
1968         int depth, len, err;
1969         ext4_lblk_t next;
1970         int mb_flags = 0, unwritten;
1971
1972         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1973                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1974         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1975                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1976                 return -EFSCORRUPTED;
1977         }
1978         depth = ext_depth(inode);
1979         ex = path[depth].p_ext;
1980         eh = path[depth].p_hdr;
1981         if (unlikely(path[depth].p_hdr == NULL)) {
1982                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1983                 return -EFSCORRUPTED;
1984         }
1985
1986         /* try to insert block into found extent and return */
1987         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1988
1989                 /*
1990                  * Try to see whether we should rather test the extent on
1991                  * right from ex, or from the left of ex. This is because
1992                  * ext4_find_extent() can return either extent on the
1993                  * left, or on the right from the searched position. This
1994                  * will make merging more effective.
1995                  */
1996                 if (ex < EXT_LAST_EXTENT(eh) &&
1997                     (le32_to_cpu(ex->ee_block) +
1998                     ext4_ext_get_actual_len(ex) <
1999                     le32_to_cpu(newext->ee_block))) {
2000                         ex += 1;
2001                         goto prepend;
2002                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
2003                            (le32_to_cpu(newext->ee_block) +
2004                            ext4_ext_get_actual_len(newext) <
2005                            le32_to_cpu(ex->ee_block)))
2006                         ex -= 1;
2007
2008                 /* Try to append newex to the ex */
2009                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
2010                         ext_debug(inode, "append [%d]%d block to %u:[%d]%d"
2011                                   "(from %llu)\n",
2012                                   ext4_ext_is_unwritten(newext),
2013                                   ext4_ext_get_actual_len(newext),
2014                                   le32_to_cpu(ex->ee_block),
2015                                   ext4_ext_is_unwritten(ex),
2016                                   ext4_ext_get_actual_len(ex),
2017                                   ext4_ext_pblock(ex));
2018                         err = ext4_ext_get_access(handle, inode,
2019                                                   path + depth);
2020                         if (err)
2021                                 return err;
2022                         unwritten = ext4_ext_is_unwritten(ex);
2023                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2024                                         + ext4_ext_get_actual_len(newext));
2025                         if (unwritten)
2026                                 ext4_ext_mark_unwritten(ex);
2027                         nearex = ex;
2028                         goto merge;
2029                 }
2030
2031 prepend:
2032                 /* Try to prepend newex to the ex */
2033                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2034                         ext_debug(inode, "prepend %u[%d]%d block to %u:[%d]%d"
2035                                   "(from %llu)\n",
2036                                   le32_to_cpu(newext->ee_block),
2037                                   ext4_ext_is_unwritten(newext),
2038                                   ext4_ext_get_actual_len(newext),
2039                                   le32_to_cpu(ex->ee_block),
2040                                   ext4_ext_is_unwritten(ex),
2041                                   ext4_ext_get_actual_len(ex),
2042                                   ext4_ext_pblock(ex));
2043                         err = ext4_ext_get_access(handle, inode,
2044                                                   path + depth);
2045                         if (err)
2046                                 return err;
2047
2048                         unwritten = ext4_ext_is_unwritten(ex);
2049                         ex->ee_block = newext->ee_block;
2050                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2051                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2052                                         + ext4_ext_get_actual_len(newext));
2053                         if (unwritten)
2054                                 ext4_ext_mark_unwritten(ex);
2055                         nearex = ex;
2056                         goto merge;
2057                 }
2058         }
2059
2060         depth = ext_depth(inode);
2061         eh = path[depth].p_hdr;
2062         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2063                 goto has_space;
2064
2065         /* probably next leaf has space for us? */
2066         fex = EXT_LAST_EXTENT(eh);
2067         next = EXT_MAX_BLOCKS;
2068         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2069                 next = ext4_ext_next_leaf_block(path);
2070         if (next != EXT_MAX_BLOCKS) {
2071                 ext_debug(inode, "next leaf block - %u\n", next);
2072                 BUG_ON(npath != NULL);
2073                 npath = ext4_find_extent(inode, next, NULL, gb_flags);
2074                 if (IS_ERR(npath))
2075                         return PTR_ERR(npath);
2076                 BUG_ON(npath->p_depth != path->p_depth);
2077                 eh = npath[depth].p_hdr;
2078                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2079                         ext_debug(inode, "next leaf isn't full(%d)\n",
2080                                   le16_to_cpu(eh->eh_entries));
2081                         path = npath;
2082                         goto has_space;
2083                 }
2084                 ext_debug(inode, "next leaf has no free space(%d,%d)\n",
2085                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2086         }
2087
2088         /*
2089          * There is no free space in the found leaf.
2090          * We're gonna add a new leaf in the tree.
2091          */
2092         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2093                 mb_flags |= EXT4_MB_USE_RESERVED;
2094         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2095                                        ppath, newext);
2096         if (err)
2097                 goto cleanup;
2098         depth = ext_depth(inode);
2099         eh = path[depth].p_hdr;
2100
2101 has_space:
2102         nearex = path[depth].p_ext;
2103
2104         err = ext4_ext_get_access(handle, inode, path + depth);
2105         if (err)
2106                 goto cleanup;
2107
2108         if (!nearex) {
2109                 /* there is no extent in this leaf, create first one */
2110                 ext_debug(inode, "first extent in the leaf: %u:%llu:[%d]%d\n",
2111                                 le32_to_cpu(newext->ee_block),
2112                                 ext4_ext_pblock(newext),
2113                                 ext4_ext_is_unwritten(newext),
2114                                 ext4_ext_get_actual_len(newext));
2115                 nearex = EXT_FIRST_EXTENT(eh);
2116         } else {
2117                 if (le32_to_cpu(newext->ee_block)
2118                            > le32_to_cpu(nearex->ee_block)) {
2119                         /* Insert after */
2120                         ext_debug(inode, "insert %u:%llu:[%d]%d before: "
2121                                         "nearest %p\n",
2122                                         le32_to_cpu(newext->ee_block),
2123                                         ext4_ext_pblock(newext),
2124                                         ext4_ext_is_unwritten(newext),
2125                                         ext4_ext_get_actual_len(newext),
2126                                         nearex);
2127                         nearex++;
2128                 } else {
2129                         /* Insert before */
2130                         BUG_ON(newext->ee_block == nearex->ee_block);
2131                         ext_debug(inode, "insert %u:%llu:[%d]%d after: "
2132                                         "nearest %p\n",
2133                                         le32_to_cpu(newext->ee_block),
2134                                         ext4_ext_pblock(newext),
2135                                         ext4_ext_is_unwritten(newext),
2136                                         ext4_ext_get_actual_len(newext),
2137                                         nearex);
2138                 }
2139                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2140                 if (len > 0) {
2141                         ext_debug(inode, "insert %u:%llu:[%d]%d: "
2142                                         "move %d extents from 0x%p to 0x%p\n",
2143                                         le32_to_cpu(newext->ee_block),
2144                                         ext4_ext_pblock(newext),
2145                                         ext4_ext_is_unwritten(newext),
2146                                         ext4_ext_get_actual_len(newext),
2147                                         len, nearex, nearex + 1);
2148                         memmove(nearex + 1, nearex,
2149                                 len * sizeof(struct ext4_extent));
2150                 }
2151         }
2152
2153         le16_add_cpu(&eh->eh_entries, 1);
2154         path[depth].p_ext = nearex;
2155         nearex->ee_block = newext->ee_block;
2156         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2157         nearex->ee_len = newext->ee_len;
2158
2159 merge:
2160         /* try to merge extents */
2161         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2162                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2163
2164
2165         /* time to correct all indexes above */
2166         err = ext4_ext_correct_indexes(handle, inode, path);
2167         if (err)
2168                 goto cleanup;
2169
2170         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2171
2172 cleanup:
2173         ext4_ext_drop_refs(npath);
2174         kfree(npath);
2175         return err;
2176 }
2177
2178 static int ext4_fill_es_cache_info(struct inode *inode,
2179                                    ext4_lblk_t block, ext4_lblk_t num,
2180                                    struct fiemap_extent_info *fieinfo)
2181 {
2182         ext4_lblk_t next, end = block + num - 1;
2183         struct extent_status es;
2184         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2185         unsigned int flags;
2186         int err;
2187
2188         while (block <= end) {
2189                 next = 0;
2190                 flags = 0;
2191                 if (!ext4_es_lookup_extent(inode, block, &next, &es))
2192                         break;
2193                 if (ext4_es_is_unwritten(&es))
2194                         flags |= FIEMAP_EXTENT_UNWRITTEN;
2195                 if (ext4_es_is_delayed(&es))
2196                         flags |= (FIEMAP_EXTENT_DELALLOC |
2197                                   FIEMAP_EXTENT_UNKNOWN);
2198                 if (ext4_es_is_hole(&es))
2199                         flags |= EXT4_FIEMAP_EXTENT_HOLE;
2200                 if (next == 0)
2201                         flags |= FIEMAP_EXTENT_LAST;
2202                 if (flags & (FIEMAP_EXTENT_DELALLOC|
2203                              EXT4_FIEMAP_EXTENT_HOLE))
2204                         es.es_pblk = 0;
2205                 else
2206                         es.es_pblk = ext4_es_pblock(&es);
2207                 err = fiemap_fill_next_extent(fieinfo,
2208                                 (__u64)es.es_lblk << blksize_bits,
2209                                 (__u64)es.es_pblk << blksize_bits,
2210                                 (__u64)es.es_len << blksize_bits,
2211                                 flags);
2212                 if (next == 0)
2213                         break;
2214                 block = next;
2215                 if (err < 0)
2216                         return err;
2217                 if (err == 1)
2218                         return 0;
2219         }
2220         return 0;
2221 }
2222
2223
2224 /*
2225  * ext4_ext_determine_hole - determine hole around given block
2226  * @inode:      inode we lookup in
2227  * @path:       path in extent tree to @lblk
2228  * @lblk:       pointer to logical block around which we want to determine hole
2229  *
2230  * Determine hole length (and start if easily possible) around given logical
2231  * block. We don't try too hard to find the beginning of the hole but @path
2232  * actually points to extent before @lblk, we provide it.
2233  *
2234  * The function returns the length of a hole starting at @lblk. We update @lblk
2235  * to the beginning of the hole if we managed to find it.
2236  */
2237 static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2238                                            struct ext4_ext_path *path,
2239                                            ext4_lblk_t *lblk)
2240 {
2241         int depth = ext_depth(inode);
2242         struct ext4_extent *ex;
2243         ext4_lblk_t len;
2244
2245         ex = path[depth].p_ext;
2246         if (ex == NULL) {
2247                 /* there is no extent yet, so gap is [0;-] */
2248                 *lblk = 0;
2249                 len = EXT_MAX_BLOCKS;
2250         } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2251                 len = le32_to_cpu(ex->ee_block) - *lblk;
2252         } else if (*lblk >= le32_to_cpu(ex->ee_block)
2253                         + ext4_ext_get_actual_len(ex)) {
2254                 ext4_lblk_t next;
2255
2256                 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2257                 next = ext4_ext_next_allocated_block(path);
2258                 BUG_ON(next == *lblk);
2259                 len = next - *lblk;
2260         } else {
2261                 BUG();
2262         }
2263         return len;
2264 }
2265
2266 /*
2267  * ext4_ext_put_gap_in_cache:
2268  * calculate boundaries of the gap that the requested block fits into
2269  * and cache this gap
2270  */
2271 static void
2272 ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2273                           ext4_lblk_t hole_len)
2274 {
2275         struct extent_status es;
2276
2277         ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
2278                                   hole_start + hole_len - 1, &es);
2279         if (es.es_len) {
2280                 /* There's delayed extent containing lblock? */
2281                 if (es.es_lblk <= hole_start)
2282                         return;
2283                 hole_len = min(es.es_lblk - hole_start, hole_len);
2284         }
2285         ext_debug(inode, " -> %u:%u\n", hole_start, hole_len);
2286         ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2287                               EXTENT_STATUS_HOLE);
2288 }
2289
2290 /*
2291  * ext4_ext_rm_idx:
2292  * removes index from the index block.
2293  */
2294 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2295                         struct ext4_ext_path *path, int depth)
2296 {
2297         int err;
2298         ext4_fsblk_t leaf;
2299
2300         /* free index block */
2301         depth--;
2302         path = path + depth;
2303         leaf = ext4_idx_pblock(path->p_idx);
2304         if (unlikely(path->p_hdr->eh_entries == 0)) {
2305                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2306                 return -EFSCORRUPTED;
2307         }
2308         err = ext4_ext_get_access(handle, inode, path);
2309         if (err)
2310                 return err;
2311
2312         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2313                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2314                 len *= sizeof(struct ext4_extent_idx);
2315                 memmove(path->p_idx, path->p_idx + 1, len);
2316         }
2317
2318         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2319         err = ext4_ext_dirty(handle, inode, path);
2320         if (err)
2321                 return err;
2322         ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
2323         trace_ext4_ext_rm_idx(inode, leaf);
2324
2325         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2326                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2327
2328         while (--depth >= 0) {
2329                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2330                         break;
2331                 path--;
2332                 err = ext4_ext_get_access(handle, inode, path);
2333                 if (err)
2334                         break;
2335                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2336                 err = ext4_ext_dirty(handle, inode, path);
2337                 if (err)
2338                         break;
2339         }
2340         return err;
2341 }
2342
2343 /*
2344  * ext4_ext_calc_credits_for_single_extent:
2345  * This routine returns max. credits that needed to insert an extent
2346  * to the extent tree.
2347  * When pass the actual path, the caller should calculate credits
2348  * under i_data_sem.
2349  */
2350 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2351                                                 struct ext4_ext_path *path)
2352 {
2353         if (path) {
2354                 int depth = ext_depth(inode);
2355                 int ret = 0;
2356
2357                 /* probably there is space in leaf? */
2358                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2359                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2360
2361                         /*
2362                          *  There are some space in the leaf tree, no
2363                          *  need to account for leaf block credit
2364                          *
2365                          *  bitmaps and block group descriptor blocks
2366                          *  and other metadata blocks still need to be
2367                          *  accounted.
2368                          */
2369                         /* 1 bitmap, 1 block group descriptor */
2370                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2371                         return ret;
2372                 }
2373         }
2374
2375         return ext4_chunk_trans_blocks(inode, nrblocks);
2376 }
2377
2378 /*
2379  * How many index/leaf blocks need to change/allocate to add @extents extents?
2380  *
2381  * If we add a single extent, then in the worse case, each tree level
2382  * index/leaf need to be changed in case of the tree split.
2383  *
2384  * If more extents are inserted, they could cause the whole tree split more
2385  * than once, but this is really rare.
2386  */
2387 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2388 {
2389         int index;
2390         int depth;
2391
2392         /* If we are converting the inline data, only one is needed here. */
2393         if (ext4_has_inline_data(inode))
2394                 return 1;
2395
2396         depth = ext_depth(inode);
2397
2398         if (extents <= 1)
2399                 index = depth * 2;
2400         else
2401                 index = depth * 3;
2402
2403         return index;
2404 }
2405
2406 static inline int get_default_free_blocks_flags(struct inode *inode)
2407 {
2408         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2409             ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2410                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2411         else if (ext4_should_journal_data(inode))
2412                 return EXT4_FREE_BLOCKS_FORGET;
2413         return 0;
2414 }
2415
2416 /*
2417  * ext4_rereserve_cluster - increment the reserved cluster count when
2418  *                          freeing a cluster with a pending reservation
2419  *
2420  * @inode - file containing the cluster
2421  * @lblk - logical block in cluster to be reserved
2422  *
2423  * Increments the reserved cluster count and adjusts quota in a bigalloc
2424  * file system when freeing a partial cluster containing at least one
2425  * delayed and unwritten block.  A partial cluster meeting that
2426  * requirement will have a pending reservation.  If so, the
2427  * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2428  * defer reserved and allocated space accounting to a subsequent call
2429  * to this function.
2430  */
2431 static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2432 {
2433         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2434         struct ext4_inode_info *ei = EXT4_I(inode);
2435
2436         dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2437
2438         spin_lock(&ei->i_block_reservation_lock);
2439         ei->i_reserved_data_blocks++;
2440         percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2441         spin_unlock(&ei->i_block_reservation_lock);
2442
2443         percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2444         ext4_remove_pending(inode, lblk);
2445 }
2446
2447 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2448                               struct ext4_extent *ex,
2449                               struct partial_cluster *partial,
2450                               ext4_lblk_t from, ext4_lblk_t to)
2451 {
2452         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2453         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2454         ext4_fsblk_t last_pblk, pblk;
2455         ext4_lblk_t num;
2456         int flags;
2457
2458         /* only extent tail removal is allowed */
2459         if (from < le32_to_cpu(ex->ee_block) ||
2460             to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2461                 ext4_error(sbi->s_sb,
2462                            "strange request: removal(2) %u-%u from %u:%u",
2463                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2464                 return 0;
2465         }
2466
2467 #ifdef EXTENTS_STATS
2468         spin_lock(&sbi->s_ext_stats_lock);
2469         sbi->s_ext_blocks += ee_len;
2470         sbi->s_ext_extents++;
2471         if (ee_len < sbi->s_ext_min)
2472                 sbi->s_ext_min = ee_len;
2473         if (ee_len > sbi->s_ext_max)
2474                 sbi->s_ext_max = ee_len;
2475         if (ext_depth(inode) > sbi->s_depth_max)
2476                 sbi->s_depth_max = ext_depth(inode);
2477         spin_unlock(&sbi->s_ext_stats_lock);
2478 #endif
2479
2480         trace_ext4_remove_blocks(inode, ex, from, to, partial);
2481
2482         /*
2483          * if we have a partial cluster, and it's different from the
2484          * cluster of the last block in the extent, we free it
2485          */
2486         last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2487
2488         if (partial->state != initial &&
2489             partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2490                 if (partial->state == tofree) {
2491                         flags = get_default_free_blocks_flags(inode);
2492                         if (ext4_is_pending(inode, partial->lblk))
2493                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2494                         ext4_free_blocks(handle, inode, NULL,
2495                                          EXT4_C2B(sbi, partial->pclu),
2496                                          sbi->s_cluster_ratio, flags);
2497                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2498                                 ext4_rereserve_cluster(inode, partial->lblk);
2499                 }
2500                 partial->state = initial;
2501         }
2502
2503         num = le32_to_cpu(ex->ee_block) + ee_len - from;
2504         pblk = ext4_ext_pblock(ex) + ee_len - num;
2505
2506         /*
2507          * We free the partial cluster at the end of the extent (if any),
2508          * unless the cluster is used by another extent (partial_cluster
2509          * state is nofree).  If a partial cluster exists here, it must be
2510          * shared with the last block in the extent.
2511          */
2512         flags = get_default_free_blocks_flags(inode);
2513
2514         /* partial, left end cluster aligned, right end unaligned */
2515         if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2516             (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2517             (partial->state != nofree)) {
2518                 if (ext4_is_pending(inode, to))
2519                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2520                 ext4_free_blocks(handle, inode, NULL,
2521                                  EXT4_PBLK_CMASK(sbi, last_pblk),
2522                                  sbi->s_cluster_ratio, flags);
2523                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2524                         ext4_rereserve_cluster(inode, to);
2525                 partial->state = initial;
2526                 flags = get_default_free_blocks_flags(inode);
2527         }
2528
2529         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2530
2531         /*
2532          * For bigalloc file systems, we never free a partial cluster
2533          * at the beginning of the extent.  Instead, we check to see if we
2534          * need to free it on a subsequent call to ext4_remove_blocks,
2535          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2536          */
2537         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2538         ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2539
2540         /* reset the partial cluster if we've freed past it */
2541         if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2542                 partial->state = initial;
2543
2544         /*
2545          * If we've freed the entire extent but the beginning is not left
2546          * cluster aligned and is not marked as ineligible for freeing we
2547          * record the partial cluster at the beginning of the extent.  It
2548          * wasn't freed by the preceding ext4_free_blocks() call, and we
2549          * need to look farther to the left to determine if it's to be freed
2550          * (not shared with another extent). Else, reset the partial
2551          * cluster - we're either  done freeing or the beginning of the
2552          * extent is left cluster aligned.
2553          */
2554         if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2555                 if (partial->state == initial) {
2556                         partial->pclu = EXT4_B2C(sbi, pblk);
2557                         partial->lblk = from;
2558                         partial->state = tofree;
2559                 }
2560         } else {
2561                 partial->state = initial;
2562         }
2563
2564         return 0;
2565 }
2566
2567 /*
2568  * ext4_ext_rm_leaf() Removes the extents associated with the
2569  * blocks appearing between "start" and "end".  Both "start"
2570  * and "end" must appear in the same extent or EIO is returned.
2571  *
2572  * @handle: The journal handle
2573  * @inode:  The files inode
2574  * @path:   The path to the leaf
2575  * @partial_cluster: The cluster which we'll have to free if all extents
2576  *                   has been released from it.  However, if this value is
2577  *                   negative, it's a cluster just to the right of the
2578  *                   punched region and it must not be freed.
2579  * @start:  The first block to remove
2580  * @end:   The last block to remove
2581  */
2582 static int
2583 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2584                  struct ext4_ext_path *path,
2585                  struct partial_cluster *partial,
2586                  ext4_lblk_t start, ext4_lblk_t end)
2587 {
2588         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2589         int err = 0, correct_index = 0;
2590         int depth = ext_depth(inode), credits, revoke_credits;
2591         struct ext4_extent_header *eh;
2592         ext4_lblk_t a, b;
2593         unsigned num;
2594         ext4_lblk_t ex_ee_block;
2595         unsigned short ex_ee_len;
2596         unsigned unwritten = 0;
2597         struct ext4_extent *ex;
2598         ext4_fsblk_t pblk;
2599
2600         /* the header must be checked already in ext4_ext_remove_space() */
2601         ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
2602         if (!path[depth].p_hdr)
2603                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2604         eh = path[depth].p_hdr;
2605         if (unlikely(path[depth].p_hdr == NULL)) {
2606                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2607                 return -EFSCORRUPTED;
2608         }
2609         /* find where to start removing */
2610         ex = path[depth].p_ext;
2611         if (!ex)
2612                 ex = EXT_LAST_EXTENT(eh);
2613
2614         ex_ee_block = le32_to_cpu(ex->ee_block);
2615         ex_ee_len = ext4_ext_get_actual_len(ex);
2616
2617         trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2618
2619         while (ex >= EXT_FIRST_EXTENT(eh) &&
2620                         ex_ee_block + ex_ee_len > start) {
2621
2622                 if (ext4_ext_is_unwritten(ex))
2623                         unwritten = 1;
2624                 else
2625                         unwritten = 0;
2626
2627                 ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
2628                           unwritten, ex_ee_len);
2629                 path[depth].p_ext = ex;
2630
2631                 a = ex_ee_block > start ? ex_ee_block : start;
2632                 b = ex_ee_block+ex_ee_len - 1 < end ?
2633                         ex_ee_block+ex_ee_len - 1 : end;
2634
2635                 ext_debug(inode, "  border %u:%u\n", a, b);
2636
2637                 /* If this extent is beyond the end of the hole, skip it */
2638                 if (end < ex_ee_block) {
2639                         /*
2640                          * We're going to skip this extent and move to another,
2641                          * so note that its first cluster is in use to avoid
2642                          * freeing it when removing blocks.  Eventually, the
2643                          * right edge of the truncated/punched region will
2644                          * be just to the left.
2645                          */
2646                         if (sbi->s_cluster_ratio > 1) {
2647                                 pblk = ext4_ext_pblock(ex);
2648                                 partial->pclu = EXT4_B2C(sbi, pblk);
2649                                 partial->state = nofree;
2650                         }
2651                         ex--;
2652                         ex_ee_block = le32_to_cpu(ex->ee_block);
2653                         ex_ee_len = ext4_ext_get_actual_len(ex);
2654                         continue;
2655                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2656                         EXT4_ERROR_INODE(inode,
2657                                          "can not handle truncate %u:%u "
2658                                          "on extent %u:%u",
2659                                          start, end, ex_ee_block,
2660                                          ex_ee_block + ex_ee_len - 1);
2661                         err = -EFSCORRUPTED;
2662                         goto out;
2663                 } else if (a != ex_ee_block) {
2664                         /* remove tail of the extent */
2665                         num = a - ex_ee_block;
2666                 } else {
2667                         /* remove whole extent: excellent! */
2668                         num = 0;
2669                 }
2670                 /*
2671                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2672                  * descriptor) for each block group; assume two block
2673                  * groups plus ex_ee_len/blocks_per_block_group for
2674                  * the worst case
2675                  */
2676                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2677                 if (ex == EXT_FIRST_EXTENT(eh)) {
2678                         correct_index = 1;
2679                         credits += (ext_depth(inode)) + 1;
2680                 }
2681                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2682                 /*
2683                  * We may end up freeing some index blocks and data from the
2684                  * punched range. Note that partial clusters are accounted for
2685                  * by ext4_free_data_revoke_credits().
2686                  */
2687                 revoke_credits =
2688                         ext4_free_metadata_revoke_credits(inode->i_sb,
2689                                                           ext_depth(inode)) +
2690                         ext4_free_data_revoke_credits(inode, b - a + 1);
2691
2692                 err = ext4_datasem_ensure_credits(handle, inode, credits,
2693                                                   credits, revoke_credits);
2694                 if (err) {
2695                         if (err > 0)
2696                                 err = -EAGAIN;
2697                         goto out;
2698                 }
2699
2700                 err = ext4_ext_get_access(handle, inode, path + depth);
2701                 if (err)
2702                         goto out;
2703
2704                 err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2705                 if (err)
2706                         goto out;
2707
2708                 if (num == 0)
2709                         /* this extent is removed; mark slot entirely unused */
2710                         ext4_ext_store_pblock(ex, 0);
2711
2712                 ex->ee_len = cpu_to_le16(num);
2713                 /*
2714                  * Do not mark unwritten if all the blocks in the
2715                  * extent have been removed.
2716                  */
2717                 if (unwritten && num)
2718                         ext4_ext_mark_unwritten(ex);
2719                 /*
2720                  * If the extent was completely released,
2721                  * we need to remove it from the leaf
2722                  */
2723                 if (num == 0) {
2724                         if (end != EXT_MAX_BLOCKS - 1) {
2725                                 /*
2726                                  * For hole punching, we need to scoot all the
2727                                  * extents up when an extent is removed so that
2728                                  * we dont have blank extents in the middle
2729                                  */
2730                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2731                                         sizeof(struct ext4_extent));
2732
2733                                 /* Now get rid of the one at the end */
2734                                 memset(EXT_LAST_EXTENT(eh), 0,
2735                                         sizeof(struct ext4_extent));
2736                         }
2737                         le16_add_cpu(&eh->eh_entries, -1);
2738                 }
2739
2740                 err = ext4_ext_dirty(handle, inode, path + depth);
2741                 if (err)
2742                         goto out;
2743
2744                 ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
2745                                 ext4_ext_pblock(ex));
2746                 ex--;
2747                 ex_ee_block = le32_to_cpu(ex->ee_block);
2748                 ex_ee_len = ext4_ext_get_actual_len(ex);
2749         }
2750
2751         if (correct_index && eh->eh_entries)
2752                 err = ext4_ext_correct_indexes(handle, inode, path);
2753
2754         /*
2755          * If there's a partial cluster and at least one extent remains in
2756          * the leaf, free the partial cluster if it isn't shared with the
2757          * current extent.  If it is shared with the current extent
2758          * we reset the partial cluster because we've reached the start of the
2759          * truncated/punched region and we're done removing blocks.
2760          */
2761         if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2762                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2763                 if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2764                         int flags = get_default_free_blocks_flags(inode);
2765
2766                         if (ext4_is_pending(inode, partial->lblk))
2767                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2768                         ext4_free_blocks(handle, inode, NULL,
2769                                          EXT4_C2B(sbi, partial->pclu),
2770                                          sbi->s_cluster_ratio, flags);
2771                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2772                                 ext4_rereserve_cluster(inode, partial->lblk);
2773                 }
2774                 partial->state = initial;
2775         }
2776
2777         /* if this leaf is free, then we should
2778          * remove it from index block above */
2779         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2780                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2781
2782 out:
2783         return err;
2784 }
2785
2786 /*
2787  * ext4_ext_more_to_rm:
2788  * returns 1 if current index has to be freed (even partial)
2789  */
2790 static int
2791 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2792 {
2793         BUG_ON(path->p_idx == NULL);
2794
2795         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2796                 return 0;
2797
2798         /*
2799          * if truncate on deeper level happened, it wasn't partial,
2800          * so we have to consider current index for truncation
2801          */
2802         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2803                 return 0;
2804         return 1;
2805 }
2806
2807 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2808                           ext4_lblk_t end)
2809 {
2810         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2811         int depth = ext_depth(inode);
2812         struct ext4_ext_path *path = NULL;
2813         struct partial_cluster partial;
2814         handle_t *handle;
2815         int i = 0, err = 0;
2816
2817         partial.pclu = 0;
2818         partial.lblk = 0;
2819         partial.state = initial;
2820
2821         ext_debug(inode, "truncate since %u to %u\n", start, end);
2822
2823         /* probably first extent we're gonna free will be last in block */
2824         handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2825                         depth + 1,
2826                         ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2827         if (IS_ERR(handle))
2828                 return PTR_ERR(handle);
2829
2830 again:
2831         trace_ext4_ext_remove_space(inode, start, end, depth);
2832
2833         /*
2834          * Check if we are removing extents inside the extent tree. If that
2835          * is the case, we are going to punch a hole inside the extent tree
2836          * so we have to check whether we need to split the extent covering
2837          * the last block to remove so we can easily remove the part of it
2838          * in ext4_ext_rm_leaf().
2839          */
2840         if (end < EXT_MAX_BLOCKS - 1) {
2841                 struct ext4_extent *ex;
2842                 ext4_lblk_t ee_block, ex_end, lblk;
2843                 ext4_fsblk_t pblk;
2844
2845                 /* find extent for or closest extent to this block */
2846                 path = ext4_find_extent(inode, end, NULL,
2847                                         EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
2848                 if (IS_ERR(path)) {
2849                         ext4_journal_stop(handle);
2850                         return PTR_ERR(path);
2851                 }
2852                 depth = ext_depth(inode);
2853                 /* Leaf not may not exist only if inode has no blocks at all */
2854                 ex = path[depth].p_ext;
2855                 if (!ex) {
2856                         if (depth) {
2857                                 EXT4_ERROR_INODE(inode,
2858                                                  "path[%d].p_hdr == NULL",
2859                                                  depth);
2860                                 err = -EFSCORRUPTED;
2861                         }
2862                         goto out;
2863                 }
2864
2865                 ee_block = le32_to_cpu(ex->ee_block);
2866                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2867
2868                 /*
2869                  * See if the last block is inside the extent, if so split
2870                  * the extent at 'end' block so we can easily remove the
2871                  * tail of the first part of the split extent in
2872                  * ext4_ext_rm_leaf().
2873                  */
2874                 if (end >= ee_block && end < ex_end) {
2875
2876                         /*
2877                          * If we're going to split the extent, note that
2878                          * the cluster containing the block after 'end' is
2879                          * in use to avoid freeing it when removing blocks.
2880                          */
2881                         if (sbi->s_cluster_ratio > 1) {
2882                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
2883                                 partial.pclu = EXT4_B2C(sbi, pblk);
2884                                 partial.state = nofree;
2885                         }
2886
2887                         /*
2888                          * Split the extent in two so that 'end' is the last
2889                          * block in the first new extent. Also we should not
2890                          * fail removing space due to ENOSPC so try to use
2891                          * reserved block if that happens.
2892                          */
2893                         err = ext4_force_split_extent_at(handle, inode, &path,
2894                                                          end + 1, 1);
2895                         if (err < 0)
2896                                 goto out;
2897
2898                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
2899                            partial.state == initial) {
2900                         /*
2901                          * If we're punching, there's an extent to the right.
2902                          * If the partial cluster hasn't been set, set it to
2903                          * that extent's first cluster and its state to nofree
2904                          * so it won't be freed should it contain blocks to be
2905                          * removed. If it's already set (tofree/nofree), we're
2906                          * retrying and keep the original partial cluster info
2907                          * so a cluster marked tofree as a result of earlier
2908                          * extent removal is not lost.
2909                          */
2910                         lblk = ex_end + 1;
2911                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2912                                                     NULL);
2913                         if (err < 0)
2914                                 goto out;
2915                         if (pblk) {
2916                                 partial.pclu = EXT4_B2C(sbi, pblk);
2917                                 partial.state = nofree;
2918                         }
2919                 }
2920         }
2921         /*
2922          * We start scanning from right side, freeing all the blocks
2923          * after i_size and walking into the tree depth-wise.
2924          */
2925         depth = ext_depth(inode);
2926         if (path) {
2927                 int k = i = depth;
2928                 while (--k > 0)
2929                         path[k].p_block =
2930                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2931         } else {
2932                 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
2933                                GFP_NOFS | __GFP_NOFAIL);
2934                 if (path == NULL) {
2935                         ext4_journal_stop(handle);
2936                         return -ENOMEM;
2937                 }
2938                 path[0].p_maxdepth = path[0].p_depth = depth;
2939                 path[0].p_hdr = ext_inode_hdr(inode);
2940                 i = 0;
2941
2942                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2943                         err = -EFSCORRUPTED;
2944                         goto out;
2945                 }
2946         }
2947         err = 0;
2948
2949         while (i >= 0 && err == 0) {
2950                 if (i == depth) {
2951                         /* this is leaf block */
2952                         err = ext4_ext_rm_leaf(handle, inode, path,
2953                                                &partial, start, end);
2954                         /* root level has p_bh == NULL, brelse() eats this */
2955                         brelse(path[i].p_bh);
2956                         path[i].p_bh = NULL;
2957                         i--;
2958                         continue;
2959                 }
2960
2961                 /* this is index block */
2962                 if (!path[i].p_hdr) {
2963                         ext_debug(inode, "initialize header\n");
2964                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2965                 }
2966
2967                 if (!path[i].p_idx) {
2968                         /* this level hasn't been touched yet */
2969                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2970                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2971                         ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
2972                                   path[i].p_hdr,
2973                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2974                 } else {
2975                         /* we were already here, see at next index */
2976                         path[i].p_idx--;
2977                 }
2978
2979                 ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
2980                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2981                                 path[i].p_idx);
2982                 if (ext4_ext_more_to_rm(path + i)) {
2983                         struct buffer_head *bh;
2984                         /* go to the next level */
2985                         ext_debug(inode, "move to level %d (block %llu)\n",
2986                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2987                         memset(path + i + 1, 0, sizeof(*path));
2988                         bh = read_extent_tree_block(inode, path[i].p_idx,
2989                                                     depth - i - 1,
2990                                                     EXT4_EX_NOCACHE);
2991                         if (IS_ERR(bh)) {
2992                                 /* should we reset i_size? */
2993                                 err = PTR_ERR(bh);
2994                                 break;
2995                         }
2996                         /* Yield here to deal with large extent trees.
2997                          * Should be a no-op if we did IO above. */
2998                         cond_resched();
2999                         if (WARN_ON(i + 1 > depth)) {
3000                                 err = -EFSCORRUPTED;
3001                                 break;
3002                         }
3003                         path[i + 1].p_bh = bh;
3004
3005                         /* save actual number of indexes since this
3006                          * number is changed at the next iteration */
3007                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3008                         i++;
3009                 } else {
3010                         /* we finished processing this index, go up */
3011                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3012                                 /* index is empty, remove it;
3013                                  * handle must be already prepared by the
3014                                  * truncatei_leaf() */
3015                                 err = ext4_ext_rm_idx(handle, inode, path, i);
3016                         }
3017                         /* root level has p_bh == NULL, brelse() eats this */
3018                         brelse(path[i].p_bh);
3019                         path[i].p_bh = NULL;
3020                         i--;
3021                         ext_debug(inode, "return to level %d\n", i);
3022                 }
3023         }
3024
3025         trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3026                                          path->p_hdr->eh_entries);
3027
3028         /*
3029          * if there's a partial cluster and we have removed the first extent
3030          * in the file, then we also free the partial cluster, if any
3031          */
3032         if (partial.state == tofree && err == 0) {
3033                 int flags = get_default_free_blocks_flags(inode);
3034
3035                 if (ext4_is_pending(inode, partial.lblk))
3036                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3037                 ext4_free_blocks(handle, inode, NULL,
3038                                  EXT4_C2B(sbi, partial.pclu),
3039                                  sbi->s_cluster_ratio, flags);
3040                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3041                         ext4_rereserve_cluster(inode, partial.lblk);
3042                 partial.state = initial;
3043         }
3044
3045         /* TODO: flexible tree reduction should be here */
3046         if (path->p_hdr->eh_entries == 0) {
3047                 /*
3048                  * truncate to zero freed all the tree,
3049                  * so we need to correct eh_depth
3050                  */
3051                 err = ext4_ext_get_access(handle, inode, path);
3052                 if (err == 0) {
3053                         ext_inode_hdr(inode)->eh_depth = 0;
3054                         ext_inode_hdr(inode)->eh_max =
3055                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3056                         err = ext4_ext_dirty(handle, inode, path);
3057                 }
3058         }
3059 out:
3060         ext4_ext_drop_refs(path);
3061         kfree(path);
3062         path = NULL;
3063         if (err == -EAGAIN)
3064                 goto again;
3065         ext4_journal_stop(handle);
3066
3067         return err;
3068 }
3069
3070 /*
3071  * called at mount time
3072  */
3073 void ext4_ext_init(struct super_block *sb)
3074 {
3075         /*
3076          * possible initialization would be here
3077          */
3078
3079         if (ext4_has_feature_extents(sb)) {
3080 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3081                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3082 #ifdef AGGRESSIVE_TEST
3083                        ", aggressive tests"
3084 #endif
3085 #ifdef CHECK_BINSEARCH
3086                        ", check binsearch"
3087 #endif
3088 #ifdef EXTENTS_STATS
3089                        ", stats"
3090 #endif
3091                        "\n");
3092 #endif
3093 #ifdef EXTENTS_STATS
3094                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3095                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3096                 EXT4_SB(sb)->s_ext_max = 0;
3097 #endif
3098         }
3099 }
3100
3101 /*
3102  * called at umount time
3103  */
3104 void ext4_ext_release(struct super_block *sb)
3105 {
3106         if (!ext4_has_feature_extents(sb))
3107                 return;
3108
3109 #ifdef EXTENTS_STATS
3110         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3111                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3112                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3113                         sbi->s_ext_blocks, sbi->s_ext_extents,
3114                         sbi->s_ext_blocks / sbi->s_ext_extents);
3115                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3116                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3117         }
3118 #endif
3119 }
3120
3121 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3122 {
3123         ext4_lblk_t  ee_block;
3124         ext4_fsblk_t ee_pblock;
3125         unsigned int ee_len;
3126
3127         ee_block  = le32_to_cpu(ex->ee_block);
3128         ee_len    = ext4_ext_get_actual_len(ex);
3129         ee_pblock = ext4_ext_pblock(ex);
3130
3131         if (ee_len == 0)
3132                 return 0;
3133
3134         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3135                                      EXTENT_STATUS_WRITTEN);
3136 }
3137
3138 /* FIXME!! we need to try to merge to left or right after zero-out  */
3139 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3140 {
3141         ext4_fsblk_t ee_pblock;
3142         unsigned int ee_len;
3143
3144         ee_len    = ext4_ext_get_actual_len(ex);
3145         ee_pblock = ext4_ext_pblock(ex);
3146         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3147                                   ee_len);
3148 }
3149
3150 /*
3151  * ext4_split_extent_at() splits an extent at given block.
3152  *
3153  * @handle: the journal handle
3154  * @inode: the file inode
3155  * @path: the path to the extent
3156  * @split: the logical block where the extent is splitted.
3157  * @split_flags: indicates if the extent could be zeroout if split fails, and
3158  *               the states(init or unwritten) of new extents.
3159  * @flags: flags used to insert new extent to extent tree.
3160  *
3161  *
3162  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3163  * of which are determined by split_flag.
3164  *
3165  * There are two cases:
3166  *  a> the extent are splitted into two extent.
3167  *  b> split is not needed, and just mark the extent.
3168  *
3169  * return 0 on success.
3170  */
3171 static int ext4_split_extent_at(handle_t *handle,
3172                              struct inode *inode,
3173                              struct ext4_ext_path **ppath,
3174                              ext4_lblk_t split,
3175                              int split_flag,
3176                              int flags)
3177 {
3178         struct ext4_ext_path *path = *ppath;
3179         ext4_fsblk_t newblock;
3180         ext4_lblk_t ee_block;
3181         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3182         struct ext4_extent *ex2 = NULL;
3183         unsigned int ee_len, depth;
3184         int err = 0;
3185
3186         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3187                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3188
3189         ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
3190
3191         ext4_ext_show_leaf(inode, path);
3192
3193         depth = ext_depth(inode);
3194         ex = path[depth].p_ext;
3195         ee_block = le32_to_cpu(ex->ee_block);
3196         ee_len = ext4_ext_get_actual_len(ex);
3197         newblock = split - ee_block + ext4_ext_pblock(ex);
3198
3199         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3200         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3201                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3202                              EXT4_EXT_MARK_UNWRIT1 |
3203                              EXT4_EXT_MARK_UNWRIT2));
3204
3205         err = ext4_ext_get_access(handle, inode, path + depth);
3206         if (err)
3207                 goto out;
3208
3209         if (split == ee_block) {
3210                 /*
3211                  * case b: block @split is the block that the extent begins with
3212                  * then we just change the state of the extent, and splitting
3213                  * is not needed.
3214                  */
3215                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3216                         ext4_ext_mark_unwritten(ex);
3217                 else
3218                         ext4_ext_mark_initialized(ex);
3219
3220                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3221                         ext4_ext_try_to_merge(handle, inode, path, ex);
3222
3223                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3224                 goto out;
3225         }
3226
3227         /* case a */
3228         memcpy(&orig_ex, ex, sizeof(orig_ex));
3229         ex->ee_len = cpu_to_le16(split - ee_block);
3230         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3231                 ext4_ext_mark_unwritten(ex);
3232
3233         /*
3234          * path may lead to new leaf, not to original leaf any more
3235          * after ext4_ext_insert_extent() returns,
3236          */
3237         err = ext4_ext_dirty(handle, inode, path + depth);
3238         if (err)
3239                 goto fix_extent_len;
3240
3241         ex2 = &newex;
3242         ex2->ee_block = cpu_to_le32(split);
3243         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3244         ext4_ext_store_pblock(ex2, newblock);
3245         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3246                 ext4_ext_mark_unwritten(ex2);
3247
3248         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3249         if (err != -ENOSPC && err != -EDQUOT)
3250                 goto out;
3251
3252         if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
3253                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3254                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3255                                 err = ext4_ext_zeroout(inode, ex2);
3256                                 zero_ex.ee_block = ex2->ee_block;
3257                                 zero_ex.ee_len = cpu_to_le16(
3258                                                 ext4_ext_get_actual_len(ex2));
3259                                 ext4_ext_store_pblock(&zero_ex,
3260                                                       ext4_ext_pblock(ex2));
3261                         } else {
3262                                 err = ext4_ext_zeroout(inode, ex);
3263                                 zero_ex.ee_block = ex->ee_block;
3264                                 zero_ex.ee_len = cpu_to_le16(
3265                                                 ext4_ext_get_actual_len(ex));
3266                                 ext4_ext_store_pblock(&zero_ex,
3267                                                       ext4_ext_pblock(ex));
3268                         }
3269                 } else {
3270                         err = ext4_ext_zeroout(inode, &orig_ex);
3271                         zero_ex.ee_block = orig_ex.ee_block;
3272                         zero_ex.ee_len = cpu_to_le16(
3273                                                 ext4_ext_get_actual_len(&orig_ex));
3274                         ext4_ext_store_pblock(&zero_ex,
3275                                               ext4_ext_pblock(&orig_ex));
3276                 }
3277
3278                 if (!err) {
3279                         /* update the extent length and mark as initialized */
3280                         ex->ee_len = cpu_to_le16(ee_len);
3281                         ext4_ext_try_to_merge(handle, inode, path, ex);
3282                         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3283                         if (!err)
3284                                 /* update extent status tree */
3285                                 err = ext4_zeroout_es(inode, &zero_ex);
3286                         /* If we failed at this point, we don't know in which
3287                          * state the extent tree exactly is so don't try to fix
3288                          * length of the original extent as it may do even more
3289                          * damage.
3290                          */
3291                         goto out;
3292                 }
3293         }
3294
3295 fix_extent_len:
3296         ex->ee_len = orig_ex.ee_len;
3297         /*
3298          * Ignore ext4_ext_dirty return value since we are already in error path
3299          * and err is a non-zero error code.
3300          */
3301         ext4_ext_dirty(handle, inode, path + path->p_depth);
3302         return err;
3303 out:
3304         ext4_ext_show_leaf(inode, path);
3305         return err;
3306 }
3307
3308 /*
3309  * ext4_split_extents() splits an extent and mark extent which is covered
3310  * by @map as split_flags indicates
3311  *
3312  * It may result in splitting the extent into multiple extents (up to three)
3313  * There are three possibilities:
3314  *   a> There is no split required
3315  *   b> Splits in two extents: Split is happening at either end of the extent
3316  *   c> Splits in three extents: Somone is splitting in middle of the extent
3317  *
3318  */
3319 static int ext4_split_extent(handle_t *handle,
3320                               struct inode *inode,
3321                               struct ext4_ext_path **ppath,
3322                               struct ext4_map_blocks *map,
3323                               int split_flag,
3324                               int flags)
3325 {
3326         struct ext4_ext_path *path = *ppath;
3327         ext4_lblk_t ee_block;
3328         struct ext4_extent *ex;
3329         unsigned int ee_len, depth;
3330         int err = 0;
3331         int unwritten;
3332         int split_flag1, flags1;
3333         int allocated = map->m_len;
3334
3335         depth = ext_depth(inode);
3336         ex = path[depth].p_ext;
3337         ee_block = le32_to_cpu(ex->ee_block);
3338         ee_len = ext4_ext_get_actual_len(ex);
3339         unwritten = ext4_ext_is_unwritten(ex);
3340
3341         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3342                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3343                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3344                 if (unwritten)
3345                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3346                                        EXT4_EXT_MARK_UNWRIT2;
3347                 if (split_flag & EXT4_EXT_DATA_VALID2)
3348                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3349                 err = ext4_split_extent_at(handle, inode, ppath,
3350                                 map->m_lblk + map->m_len, split_flag1, flags1);
3351                 if (err)
3352                         goto out;
3353         } else {
3354                 allocated = ee_len - (map->m_lblk - ee_block);
3355         }
3356         /*
3357          * Update path is required because previous ext4_split_extent_at() may
3358          * result in split of original leaf or extent zeroout.
3359          */
3360         path = ext4_find_extent(inode, map->m_lblk, ppath, flags);
3361         if (IS_ERR(path))
3362                 return PTR_ERR(path);
3363         depth = ext_depth(inode);
3364         ex = path[depth].p_ext;
3365         if (!ex) {
3366                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3367                                  (unsigned long) map->m_lblk);
3368                 return -EFSCORRUPTED;
3369         }
3370         unwritten = ext4_ext_is_unwritten(ex);
3371
3372         if (map->m_lblk >= ee_block) {
3373                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3374                 if (unwritten) {
3375                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3376                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3377                                                      EXT4_EXT_MARK_UNWRIT2);
3378                 }
3379                 err = ext4_split_extent_at(handle, inode, ppath,
3380                                 map->m_lblk, split_flag1, flags);
3381                 if (err)
3382                         goto out;
3383         }
3384
3385         ext4_ext_show_leaf(inode, path);
3386 out:
3387         return err ? err : allocated;
3388 }
3389
3390 /*
3391  * This function is called by ext4_ext_map_blocks() if someone tries to write
3392  * to an unwritten extent. It may result in splitting the unwritten
3393  * extent into multiple extents (up to three - one initialized and two
3394  * unwritten).
3395  * There are three possibilities:
3396  *   a> There is no split required: Entire extent should be initialized
3397  *   b> Splits in two extents: Write is happening at either end of the extent
3398  *   c> Splits in three extents: Somone is writing in middle of the extent
3399  *
3400  * Pre-conditions:
3401  *  - The extent pointed to by 'path' is unwritten.
3402  *  - The extent pointed to by 'path' contains a superset
3403  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3404  *
3405  * Post-conditions on success:
3406  *  - the returned value is the number of blocks beyond map->l_lblk
3407  *    that are allocated and initialized.
3408  *    It is guaranteed to be >= map->m_len.
3409  */
3410 static int ext4_ext_convert_to_initialized(handle_t *handle,
3411                                            struct inode *inode,
3412                                            struct ext4_map_blocks *map,
3413                                            struct ext4_ext_path **ppath,
3414                                            int flags)
3415 {
3416         struct ext4_ext_path *path = *ppath;
3417         struct ext4_sb_info *sbi;
3418         struct ext4_extent_header *eh;
3419         struct ext4_map_blocks split_map;
3420         struct ext4_extent zero_ex1, zero_ex2;
3421         struct ext4_extent *ex, *abut_ex;
3422         ext4_lblk_t ee_block, eof_block;
3423         unsigned int ee_len, depth, map_len = map->m_len;
3424         int allocated = 0, max_zeroout = 0;
3425         int err = 0;
3426         int split_flag = EXT4_EXT_DATA_VALID2;
3427
3428         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3429                   (unsigned long long)map->m_lblk, map_len);
3430
3431         sbi = EXT4_SB(inode->i_sb);
3432         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3433                         >> inode->i_sb->s_blocksize_bits;
3434         if (eof_block < map->m_lblk + map_len)
3435                 eof_block = map->m_lblk + map_len;
3436
3437         depth = ext_depth(inode);
3438         eh = path[depth].p_hdr;
3439         ex = path[depth].p_ext;
3440         ee_block = le32_to_cpu(ex->ee_block);
3441         ee_len = ext4_ext_get_actual_len(ex);
3442         zero_ex1.ee_len = 0;
3443         zero_ex2.ee_len = 0;
3444
3445         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3446
3447         /* Pre-conditions */
3448         BUG_ON(!ext4_ext_is_unwritten(ex));
3449         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3450
3451         /*
3452          * Attempt to transfer newly initialized blocks from the currently
3453          * unwritten extent to its neighbor. This is much cheaper
3454          * than an insertion followed by a merge as those involve costly
3455          * memmove() calls. Transferring to the left is the common case in
3456          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3457          * followed by append writes.
3458          *
3459          * Limitations of the current logic:
3460          *  - L1: we do not deal with writes covering the whole extent.
3461          *    This would require removing the extent if the transfer
3462          *    is possible.
3463          *  - L2: we only attempt to merge with an extent stored in the
3464          *    same extent tree node.
3465          */
3466         if ((map->m_lblk == ee_block) &&
3467                 /* See if we can merge left */
3468                 (map_len < ee_len) &&           /*L1*/
3469                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3470                 ext4_lblk_t prev_lblk;
3471                 ext4_fsblk_t prev_pblk, ee_pblk;
3472                 unsigned int prev_len;
3473
3474                 abut_ex = ex - 1;
3475                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3476                 prev_len = ext4_ext_get_actual_len(abut_ex);
3477                 prev_pblk = ext4_ext_pblock(abut_ex);
3478                 ee_pblk = ext4_ext_pblock(ex);
3479
3480                 /*
3481                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3482                  * upon those conditions:
3483                  * - C1: abut_ex is initialized,
3484                  * - C2: abut_ex is logically abutting ex,
3485                  * - C3: abut_ex is physically abutting ex,
3486                  * - C4: abut_ex can receive the additional blocks without
3487                  *   overflowing the (initialized) length limit.
3488                  */
3489                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3490                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3491                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3492                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3493                         err = ext4_ext_get_access(handle, inode, path + depth);
3494                         if (err)
3495                                 goto out;
3496
3497                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3498                                 map, ex, abut_ex);
3499
3500                         /* Shift the start of ex by 'map_len' blocks */
3501                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3502                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3503                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3504                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3505
3506                         /* Extend abut_ex by 'map_len' blocks */
3507                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3508
3509                         /* Result: number of initialized blocks past m_lblk */
3510                         allocated = map_len;
3511                 }
3512         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3513                    (map_len < ee_len) &&        /*L1*/
3514                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3515                 /* See if we can merge right */
3516                 ext4_lblk_t next_lblk;
3517                 ext4_fsblk_t next_pblk, ee_pblk;
3518                 unsigned int next_len;
3519
3520                 abut_ex = ex + 1;
3521                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3522                 next_len = ext4_ext_get_actual_len(abut_ex);
3523                 next_pblk = ext4_ext_pblock(abut_ex);
3524                 ee_pblk = ext4_ext_pblock(ex);
3525
3526                 /*
3527                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3528                  * upon those conditions:
3529                  * - C1: abut_ex is initialized,
3530                  * - C2: abut_ex is logically abutting ex,
3531                  * - C3: abut_ex is physically abutting ex,
3532                  * - C4: abut_ex can receive the additional blocks without
3533                  *   overflowing the (initialized) length limit.
3534                  */
3535                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3536                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3537                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3538                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3539                         err = ext4_ext_get_access(handle, inode, path + depth);
3540                         if (err)
3541                                 goto out;
3542
3543                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3544                                 map, ex, abut_ex);
3545
3546                         /* Shift the start of abut_ex by 'map_len' blocks */
3547                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3548                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3549                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3550                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3551
3552                         /* Extend abut_ex by 'map_len' blocks */
3553                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3554
3555                         /* Result: number of initialized blocks past m_lblk */
3556                         allocated = map_len;
3557                 }
3558         }
3559         if (allocated) {
3560                 /* Mark the block containing both extents as dirty */
3561                 err = ext4_ext_dirty(handle, inode, path + depth);
3562
3563                 /* Update path to point to the right extent */
3564                 path[depth].p_ext = abut_ex;
3565                 goto out;
3566         } else
3567                 allocated = ee_len - (map->m_lblk - ee_block);
3568
3569         WARN_ON(map->m_lblk < ee_block);
3570         /*
3571          * It is safe to convert extent to initialized via explicit
3572          * zeroout only if extent is fully inside i_size or new_size.
3573          */
3574         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3575
3576         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3577                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3578                         (inode->i_sb->s_blocksize_bits - 10);
3579
3580         /*
3581          * five cases:
3582          * 1. split the extent into three extents.
3583          * 2. split the extent into two extents, zeroout the head of the first
3584          *    extent.
3585          * 3. split the extent into two extents, zeroout the tail of the second
3586          *    extent.
3587          * 4. split the extent into two extents with out zeroout.
3588          * 5. no splitting needed, just possibly zeroout the head and / or the
3589          *    tail of the extent.
3590          */
3591         split_map.m_lblk = map->m_lblk;
3592         split_map.m_len = map->m_len;
3593
3594         if (max_zeroout && (allocated > split_map.m_len)) {
3595                 if (allocated <= max_zeroout) {
3596                         /* case 3 or 5 */
3597                         zero_ex1.ee_block =
3598                                  cpu_to_le32(split_map.m_lblk +
3599                                              split_map.m_len);
3600                         zero_ex1.ee_len =
3601                                 cpu_to_le16(allocated - split_map.m_len);
3602                         ext4_ext_store_pblock(&zero_ex1,
3603                                 ext4_ext_pblock(ex) + split_map.m_lblk +
3604                                 split_map.m_len - ee_block);
3605                         err = ext4_ext_zeroout(inode, &zero_ex1);
3606                         if (err)
3607                                 goto fallback;
3608                         split_map.m_len = allocated;
3609                 }
3610                 if (split_map.m_lblk - ee_block + split_map.m_len <
3611                                                                 max_zeroout) {
3612                         /* case 2 or 5 */
3613                         if (split_map.m_lblk != ee_block) {
3614                                 zero_ex2.ee_block = ex->ee_block;
3615                                 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3616                                                         ee_block);
3617                                 ext4_ext_store_pblock(&zero_ex2,
3618                                                       ext4_ext_pblock(ex));
3619                                 err = ext4_ext_zeroout(inode, &zero_ex2);
3620                                 if (err)
3621                                         goto fallback;
3622                         }
3623
3624                         split_map.m_len += split_map.m_lblk - ee_block;
3625                         split_map.m_lblk = ee_block;
3626                         allocated = map->m_len;
3627                 }
3628         }
3629
3630 fallback:
3631         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3632                                 flags);
3633         if (err > 0)
3634                 err = 0;
3635 out:
3636         /* If we have gotten a failure, don't zero out status tree */
3637         if (!err) {
3638                 err = ext4_zeroout_es(inode, &zero_ex1);
3639                 if (!err)
3640                         err = ext4_zeroout_es(inode, &zero_ex2);
3641         }
3642         return err ? err : allocated;
3643 }
3644
3645 /*
3646  * This function is called by ext4_ext_map_blocks() from
3647  * ext4_get_blocks_dio_write() when DIO to write
3648  * to an unwritten extent.
3649  *
3650  * Writing to an unwritten extent may result in splitting the unwritten
3651  * extent into multiple initialized/unwritten extents (up to three)
3652  * There are three possibilities:
3653  *   a> There is no split required: Entire extent should be unwritten
3654  *   b> Splits in two extents: Write is happening at either end of the extent
3655  *   c> Splits in three extents: Somone is writing in middle of the extent
3656  *
3657  * This works the same way in the case of initialized -> unwritten conversion.
3658  *
3659  * One of more index blocks maybe needed if the extent tree grow after
3660  * the unwritten extent split. To prevent ENOSPC occur at the IO
3661  * complete, we need to split the unwritten extent before DIO submit
3662  * the IO. The unwritten extent called at this time will be split
3663  * into three unwritten extent(at most). After IO complete, the part
3664  * being filled will be convert to initialized by the end_io callback function
3665  * via ext4_convert_unwritten_extents().
3666  *
3667  * Returns the size of unwritten extent to be written on success.
3668  */
3669 static int ext4_split_convert_extents(handle_t *handle,
3670                                         struct inode *inode,
3671                                         struct ext4_map_blocks *map,
3672                                         struct ext4_ext_path **ppath,
3673                                         int flags)
3674 {
3675         struct ext4_ext_path *path = *ppath;
3676         ext4_lblk_t eof_block;
3677         ext4_lblk_t ee_block;
3678         struct ext4_extent *ex;
3679         unsigned int ee_len;
3680         int split_flag = 0, depth;
3681
3682         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3683                   (unsigned long long)map->m_lblk, map->m_len);
3684
3685         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3686                         >> inode->i_sb->s_blocksize_bits;
3687         if (eof_block < map->m_lblk + map->m_len)
3688                 eof_block = map->m_lblk + map->m_len;
3689         /*
3690          * It is safe to convert extent to initialized via explicit
3691          * zeroout only if extent is fully inside i_size or new_size.
3692          */
3693         depth = ext_depth(inode);
3694         ex = path[depth].p_ext;
3695         ee_block = le32_to_cpu(ex->ee_block);
3696         ee_len = ext4_ext_get_actual_len(ex);
3697
3698         /* Convert to unwritten */
3699         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3700                 split_flag |= EXT4_EXT_DATA_VALID1;
3701         /* Convert to initialized */
3702         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3703                 split_flag |= ee_block + ee_len <= eof_block ?
3704                               EXT4_EXT_MAY_ZEROOUT : 0;
3705                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3706         }
3707         flags |= EXT4_GET_BLOCKS_PRE_IO;
3708         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3709 }
3710
3711 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3712                                                 struct inode *inode,
3713                                                 struct ext4_map_blocks *map,
3714                                                 struct ext4_ext_path **ppath)
3715 {
3716         struct ext4_ext_path *path = *ppath;
3717         struct ext4_extent *ex;
3718         ext4_lblk_t ee_block;
3719         unsigned int ee_len;
3720         int depth;
3721         int err = 0;
3722
3723         depth = ext_depth(inode);
3724         ex = path[depth].p_ext;
3725         ee_block = le32_to_cpu(ex->ee_block);
3726         ee_len = ext4_ext_get_actual_len(ex);
3727
3728         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3729                   (unsigned long long)ee_block, ee_len);
3730
3731         /* If extent is larger than requested it is a clear sign that we still
3732          * have some extent state machine issues left. So extent_split is still
3733          * required.
3734          * TODO: Once all related issues will be fixed this situation should be
3735          * illegal.
3736          */
3737         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3738 #ifdef CONFIG_EXT4_DEBUG
3739                 ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3740                              " len %u; IO logical block %llu, len %u",
3741                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3742                              (unsigned long long)map->m_lblk, map->m_len);
3743 #endif
3744                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3745                                                  EXT4_GET_BLOCKS_CONVERT);
3746                 if (err < 0)
3747                         return err;
3748                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3749                 if (IS_ERR(path))
3750                         return PTR_ERR(path);
3751                 depth = ext_depth(inode);
3752                 ex = path[depth].p_ext;
3753         }
3754
3755         err = ext4_ext_get_access(handle, inode, path + depth);
3756         if (err)
3757                 goto out;
3758         /* first mark the extent as initialized */
3759         ext4_ext_mark_initialized(ex);
3760
3761         /* note: ext4_ext_correct_indexes() isn't needed here because
3762          * borders are not changed
3763          */
3764         ext4_ext_try_to_merge(handle, inode, path, ex);
3765
3766         /* Mark modified extent as dirty */
3767         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3768 out:
3769         ext4_ext_show_leaf(inode, path);
3770         return err;
3771 }
3772
3773 static int
3774 convert_initialized_extent(handle_t *handle, struct inode *inode,
3775                            struct ext4_map_blocks *map,
3776                            struct ext4_ext_path **ppath,
3777                            unsigned int *allocated)
3778 {
3779         struct ext4_ext_path *path = *ppath;
3780         struct ext4_extent *ex;
3781         ext4_lblk_t ee_block;
3782         unsigned int ee_len;
3783         int depth;
3784         int err = 0;
3785
3786         /*
3787          * Make sure that the extent is no bigger than we support with
3788          * unwritten extent
3789          */
3790         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3791                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3792
3793         depth = ext_depth(inode);
3794         ex = path[depth].p_ext;
3795         ee_block = le32_to_cpu(ex->ee_block);
3796         ee_len = ext4_ext_get_actual_len(ex);
3797
3798         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3799                   (unsigned long long)ee_block, ee_len);
3800
3801         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3802                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3803                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3804                 if (err < 0)
3805                         return err;
3806                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3807                 if (IS_ERR(path))
3808                         return PTR_ERR(path);
3809                 depth = ext_depth(inode);
3810                 ex = path[depth].p_ext;
3811                 if (!ex) {
3812                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3813                                          (unsigned long) map->m_lblk);
3814                         return -EFSCORRUPTED;
3815                 }
3816         }
3817
3818         err = ext4_ext_get_access(handle, inode, path + depth);
3819         if (err)
3820                 return err;
3821         /* first mark the extent as unwritten */
3822         ext4_ext_mark_unwritten(ex);
3823
3824         /* note: ext4_ext_correct_indexes() isn't needed here because
3825          * borders are not changed
3826          */
3827         ext4_ext_try_to_merge(handle, inode, path, ex);
3828
3829         /* Mark modified extent as dirty */
3830         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3831         if (err)
3832                 return err;
3833         ext4_ext_show_leaf(inode, path);
3834
3835         ext4_update_inode_fsync_trans(handle, inode, 1);
3836
3837         map->m_flags |= EXT4_MAP_UNWRITTEN;
3838         if (*allocated > map->m_len)
3839                 *allocated = map->m_len;
3840         map->m_len = *allocated;
3841         return 0;
3842 }
3843
3844 static int
3845 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3846                         struct ext4_map_blocks *map,
3847                         struct ext4_ext_path **ppath, int flags,
3848                         unsigned int allocated, ext4_fsblk_t newblock)
3849 {
3850         struct ext4_ext_path __maybe_unused *path = *ppath;
3851         int ret = 0;
3852         int err = 0;
3853
3854         ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
3855                   (unsigned long long)map->m_lblk, map->m_len, flags,
3856                   allocated);
3857         ext4_ext_show_leaf(inode, path);
3858
3859         /*
3860          * When writing into unwritten space, we should not fail to
3861          * allocate metadata blocks for the new extent block if needed.
3862          */
3863         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3864
3865         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
3866                                                     allocated, newblock);
3867
3868         /* get_block() before submitting IO, split the extent */
3869         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
3870                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
3871                                          flags | EXT4_GET_BLOCKS_CONVERT);
3872                 if (ret < 0) {
3873                         err = ret;
3874                         goto out2;
3875                 }
3876                 /*
3877                  * shouldn't get a 0 return when splitting an extent unless
3878                  * m_len is 0 (bug) or extent has been corrupted
3879                  */
3880                 if (unlikely(ret == 0)) {
3881                         EXT4_ERROR_INODE(inode,
3882                                          "unexpected ret == 0, m_len = %u",
3883                                          map->m_len);
3884                         err = -EFSCORRUPTED;
3885                         goto out2;
3886                 }
3887                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3888                 goto out;
3889         }
3890         /* IO end_io complete, convert the filled extent to written */
3891         if (flags & EXT4_GET_BLOCKS_CONVERT) {
3892                 err = ext4_convert_unwritten_extents_endio(handle, inode, map,
3893                                                            ppath);
3894                 if (err < 0)
3895                         goto out2;
3896                 ext4_update_inode_fsync_trans(handle, inode, 1);
3897                 goto map_out;
3898         }
3899         /* buffered IO cases */
3900         /*
3901          * repeat fallocate creation request
3902          * we already have an unwritten extent
3903          */
3904         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
3905                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3906                 goto map_out;
3907         }
3908
3909         /* buffered READ or buffered write_begin() lookup */
3910         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3911                 /*
3912                  * We have blocks reserved already.  We
3913                  * return allocated blocks so that delalloc
3914                  * won't do block reservation for us.  But
3915                  * the buffer head will be unmapped so that
3916                  * a read from the block returns 0s.
3917                  */
3918                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3919                 goto out1;
3920         }
3921
3922         /*
3923          * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
3924          * For buffered writes, at writepage time, etc.  Convert a
3925          * discovered unwritten extent to written.
3926          */
3927         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
3928         if (ret < 0) {
3929                 err = ret;
3930                 goto out2;
3931         }
3932         ext4_update_inode_fsync_trans(handle, inode, 1);
3933         /*
3934          * shouldn't get a 0 return when converting an unwritten extent
3935          * unless m_len is 0 (bug) or extent has been corrupted
3936          */
3937         if (unlikely(ret == 0)) {
3938                 EXT4_ERROR_INODE(inode, "unexpected ret == 0, m_len = %u",
3939                                  map->m_len);
3940                 err = -EFSCORRUPTED;
3941                 goto out2;
3942         }
3943
3944 out:
3945         allocated = ret;
3946         map->m_flags |= EXT4_MAP_NEW;
3947 map_out:
3948         map->m_flags |= EXT4_MAP_MAPPED;
3949 out1:
3950         map->m_pblk = newblock;
3951         if (allocated > map->m_len)
3952                 allocated = map->m_len;
3953         map->m_len = allocated;
3954         ext4_ext_show_leaf(inode, path);
3955 out2:
3956         return err ? err : allocated;
3957 }
3958
3959 /*
3960  * get_implied_cluster_alloc - check to see if the requested
3961  * allocation (in the map structure) overlaps with a cluster already
3962  * allocated in an extent.
3963  *      @sb     The filesystem superblock structure
3964  *      @map    The requested lblk->pblk mapping
3965  *      @ex     The extent structure which might contain an implied
3966  *                      cluster allocation
3967  *
3968  * This function is called by ext4_ext_map_blocks() after we failed to
3969  * find blocks that were already in the inode's extent tree.  Hence,
3970  * we know that the beginning of the requested region cannot overlap
3971  * the extent from the inode's extent tree.  There are three cases we
3972  * want to catch.  The first is this case:
3973  *
3974  *               |--- cluster # N--|
3975  *    |--- extent ---|  |---- requested region ---|
3976  *                      |==========|
3977  *
3978  * The second case that we need to test for is this one:
3979  *
3980  *   |--------- cluster # N ----------------|
3981  *         |--- requested region --|   |------- extent ----|
3982  *         |=======================|
3983  *
3984  * The third case is when the requested region lies between two extents
3985  * within the same cluster:
3986  *          |------------- cluster # N-------------|
3987  * |----- ex -----|                  |---- ex_right ----|
3988  *                  |------ requested region ------|
3989  *                  |================|
3990  *
3991  * In each of the above cases, we need to set the map->m_pblk and
3992  * map->m_len so it corresponds to the return the extent labelled as
3993  * "|====|" from cluster #N, since it is already in use for data in
3994  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
3995  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
3996  * as a new "allocated" block region.  Otherwise, we will return 0 and
3997  * ext4_ext_map_blocks() will then allocate one or more new clusters
3998  * by calling ext4_mb_new_blocks().
3999  */
4000 static int get_implied_cluster_alloc(struct super_block *sb,
4001                                      struct ext4_map_blocks *map,
4002                                      struct ext4_extent *ex,
4003                                      struct ext4_ext_path *path)
4004 {
4005         struct ext4_sb_info *sbi = EXT4_SB(sb);
4006         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4007         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4008         ext4_lblk_t rr_cluster_start;
4009         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4010         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4011         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4012
4013         /* The extent passed in that we are trying to match */
4014         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4015         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4016
4017         /* The requested region passed into ext4_map_blocks() */
4018         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4019
4020         if ((rr_cluster_start == ex_cluster_end) ||
4021             (rr_cluster_start == ex_cluster_start)) {
4022                 if (rr_cluster_start == ex_cluster_end)
4023                         ee_start += ee_len - 1;
4024                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4025                 map->m_len = min(map->m_len,
4026                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4027                 /*
4028                  * Check for and handle this case:
4029                  *
4030                  *   |--------- cluster # N-------------|
4031                  *                     |------- extent ----|
4032                  *         |--- requested region ---|
4033                  *         |===========|
4034                  */
4035
4036                 if (map->m_lblk < ee_block)
4037                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4038
4039                 /*
4040                  * Check for the case where there is already another allocated
4041                  * block to the right of 'ex' but before the end of the cluster.
4042                  *
4043                  *          |------------- cluster # N-------------|
4044                  * |----- ex -----|                  |---- ex_right ----|
4045                  *                  |------ requested region ------|
4046                  *                  |================|
4047                  */
4048                 if (map->m_lblk > ee_block) {
4049                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4050                         map->m_len = min(map->m_len, next - map->m_lblk);
4051                 }
4052
4053                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4054                 return 1;
4055         }
4056
4057         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4058         return 0;
4059 }
4060
4061
4062 /*
4063  * Block allocation/map/preallocation routine for extents based files
4064  *
4065  *
4066  * Need to be called with
4067  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4068  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4069  *
4070  * return > 0, number of blocks already mapped/allocated
4071  *          if create == 0 and these are pre-allocated blocks
4072  *              buffer head is unmapped
4073  *          otherwise blocks are mapped
4074  *
4075  * return = 0, if plain look up failed (blocks have not been allocated)
4076  *          buffer head is unmapped
4077  *
4078  * return < 0, error case.
4079  */
4080 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4081                         struct ext4_map_blocks *map, int flags)
4082 {
4083         struct ext4_ext_path *path = NULL;
4084         struct ext4_extent newex, *ex, ex2;
4085         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4086         ext4_fsblk_t newblock = 0, pblk;
4087         int err = 0, depth, ret;
4088         unsigned int allocated = 0, offset = 0;
4089         unsigned int allocated_clusters = 0;
4090         struct ext4_allocation_request ar;
4091         ext4_lblk_t cluster_offset;
4092
4093         ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
4094         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4095
4096         /* find extent for this block */
4097         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4098         if (IS_ERR(path)) {
4099                 err = PTR_ERR(path);
4100                 path = NULL;
4101                 goto out;
4102         }
4103
4104         depth = ext_depth(inode);
4105
4106         /*
4107          * consistent leaf must not be empty;
4108          * this situation is possible, though, _during_ tree modification;
4109          * this is why assert can't be put in ext4_find_extent()
4110          */
4111         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4112                 EXT4_ERROR_INODE(inode, "bad extent address "
4113                                  "lblock: %lu, depth: %d pblock %lld",
4114                                  (unsigned long) map->m_lblk, depth,
4115                                  path[depth].p_block);
4116                 err = -EFSCORRUPTED;
4117                 goto out;
4118         }
4119
4120         ex = path[depth].p_ext;
4121         if (ex) {
4122                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4123                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4124                 unsigned short ee_len;
4125
4126
4127                 /*
4128                  * unwritten extents are treated as holes, except that
4129                  * we split out initialized portions during a write.
4130                  */
4131                 ee_len = ext4_ext_get_actual_len(ex);
4132
4133                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4134
4135                 /* if found extent covers block, simply return it */
4136                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4137                         newblock = map->m_lblk - ee_block + ee_start;
4138                         /* number of remaining blocks in the extent */
4139                         allocated = ee_len - (map->m_lblk - ee_block);
4140                         ext_debug(inode, "%u fit into %u:%d -> %llu\n",
4141                                   map->m_lblk, ee_block, ee_len, newblock);
4142
4143                         /*
4144                          * If the extent is initialized check whether the
4145                          * caller wants to convert it to unwritten.
4146                          */
4147                         if ((!ext4_ext_is_unwritten(ex)) &&
4148                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4149                                 err = convert_initialized_extent(handle,
4150                                         inode, map, &path, &allocated);
4151                                 goto out;
4152                         } else if (!ext4_ext_is_unwritten(ex)) {
4153                                 map->m_flags |= EXT4_MAP_MAPPED;
4154                                 map->m_pblk = newblock;
4155                                 if (allocated > map->m_len)
4156                                         allocated = map->m_len;
4157                                 map->m_len = allocated;
4158                                 ext4_ext_show_leaf(inode, path);
4159                                 goto out;
4160                         }
4161
4162                         ret = ext4_ext_handle_unwritten_extents(
4163                                 handle, inode, map, &path, flags,
4164                                 allocated, newblock);
4165                         if (ret < 0)
4166                                 err = ret;
4167                         else
4168                                 allocated = ret;
4169                         goto out;
4170                 }
4171         }
4172
4173         /*
4174          * requested block isn't allocated yet;
4175          * we couldn't try to create block if create flag is zero
4176          */
4177         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4178                 ext4_lblk_t hole_start, hole_len;
4179
4180                 hole_start = map->m_lblk;
4181                 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4182                 /*
4183                  * put just found gap into cache to speed up
4184                  * subsequent requests
4185                  */
4186                 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4187
4188                 /* Update hole_len to reflect hole size after map->m_lblk */
4189                 if (hole_start != map->m_lblk)
4190                         hole_len -= map->m_lblk - hole_start;
4191                 map->m_pblk = 0;
4192                 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4193
4194                 goto out;
4195         }
4196
4197         /*
4198          * Okay, we need to do block allocation.
4199          */
4200         newex.ee_block = cpu_to_le32(map->m_lblk);
4201         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4202
4203         /*
4204          * If we are doing bigalloc, check to see if the extent returned
4205          * by ext4_find_extent() implies a cluster we can use.
4206          */
4207         if (cluster_offset && ex &&
4208             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4209                 ar.len = allocated = map->m_len;
4210                 newblock = map->m_pblk;
4211                 goto got_allocated_blocks;
4212         }
4213
4214         /* find neighbour allocated blocks */
4215         ar.lleft = map->m_lblk;
4216         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4217         if (err)
4218                 goto out;
4219         ar.lright = map->m_lblk;
4220         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4221         if (err < 0)
4222                 goto out;
4223
4224         /* Check if the extent after searching to the right implies a
4225          * cluster we can use. */
4226         if ((sbi->s_cluster_ratio > 1) && err &&
4227             get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
4228                 ar.len = allocated = map->m_len;
4229                 newblock = map->m_pblk;
4230                 goto got_allocated_blocks;
4231         }
4232
4233         /*
4234          * See if request is beyond maximum number of blocks we can have in
4235          * a single extent. For an initialized extent this limit is
4236          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4237          * EXT_UNWRITTEN_MAX_LEN.
4238          */
4239         if (map->m_len > EXT_INIT_MAX_LEN &&
4240             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4241                 map->m_len = EXT_INIT_MAX_LEN;
4242         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4243                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4244                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4245
4246         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4247         newex.ee_len = cpu_to_le16(map->m_len);
4248         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4249         if (err)
4250                 allocated = ext4_ext_get_actual_len(&newex);
4251         else
4252                 allocated = map->m_len;
4253
4254         /* allocate new block */
4255         ar.inode = inode;
4256         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4257         ar.logical = map->m_lblk;
4258         /*
4259          * We calculate the offset from the beginning of the cluster
4260          * for the logical block number, since when we allocate a
4261          * physical cluster, the physical block should start at the
4262          * same offset from the beginning of the cluster.  This is
4263          * needed so that future calls to get_implied_cluster_alloc()
4264          * work correctly.
4265          */
4266         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4267         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4268         ar.goal -= offset;
4269         ar.logical -= offset;
4270         if (S_ISREG(inode->i_mode))
4271                 ar.flags = EXT4_MB_HINT_DATA;
4272         else
4273                 /* disable in-core preallocation for non-regular files */
4274                 ar.flags = 0;
4275         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4276                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4277         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4278                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4279         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4280                 ar.flags |= EXT4_MB_USE_RESERVED;
4281         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4282         if (!newblock)
4283                 goto out;
4284         allocated_clusters = ar.len;
4285         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4286         ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
4287                   ar.goal, newblock, ar.len, allocated);
4288         if (ar.len > allocated)
4289                 ar.len = allocated;
4290
4291 got_allocated_blocks:
4292         /* try to insert new extent into found leaf and return */
4293         pblk = newblock + offset;
4294         ext4_ext_store_pblock(&newex, pblk);
4295         newex.ee_len = cpu_to_le16(ar.len);
4296         /* Mark unwritten */
4297         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4298                 ext4_ext_mark_unwritten(&newex);
4299                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4300         }
4301
4302         err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags);
4303         if (err) {
4304                 if (allocated_clusters) {
4305                         int fb_flags = 0;
4306
4307                         /*
4308                          * free data blocks we just allocated.
4309                          * not a good idea to call discard here directly,
4310                          * but otherwise we'd need to call it every free().
4311                          */
4312                         ext4_discard_preallocations(inode, 0);
4313                         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4314                                 fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
4315                         ext4_free_blocks(handle, inode, NULL, newblock,
4316                                          EXT4_C2B(sbi, allocated_clusters),
4317                                          fb_flags);
4318                 }
4319                 goto out;
4320         }
4321
4322         /*
4323          * Reduce the reserved cluster count to reflect successful deferred
4324          * allocation of delayed allocated clusters or direct allocation of
4325          * clusters discovered to be delayed allocated.  Once allocated, a
4326          * cluster is not included in the reserved count.
4327          */
4328         if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
4329                 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4330                         /*
4331                          * When allocating delayed allocated clusters, simply
4332                          * reduce the reserved cluster count and claim quota
4333                          */
4334                         ext4_da_update_reserve_space(inode, allocated_clusters,
4335                                                         1);
4336                 } else {
4337                         ext4_lblk_t lblk, len;
4338                         unsigned int n;
4339
4340                         /*
4341                          * When allocating non-delayed allocated clusters
4342                          * (from fallocate, filemap, DIO, or clusters
4343                          * allocated when delalloc has been disabled by
4344                          * ext4_nonda_switch), reduce the reserved cluster
4345                          * count by the number of allocated clusters that
4346                          * have previously been delayed allocated.  Quota
4347                          * has been claimed by ext4_mb_new_blocks() above,
4348                          * so release the quota reservations made for any
4349                          * previously delayed allocated clusters.
4350                          */
4351                         lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4352                         len = allocated_clusters << sbi->s_cluster_bits;
4353                         n = ext4_es_delayed_clu(inode, lblk, len);
4354                         if (n > 0)
4355                                 ext4_da_update_reserve_space(inode, (int) n, 0);
4356                 }
4357         }
4358
4359         /*
4360          * Cache the extent and update transaction to commit on fdatasync only
4361          * when it is _not_ an unwritten extent.
4362          */
4363         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4364                 ext4_update_inode_fsync_trans(handle, inode, 1);
4365         else
4366                 ext4_update_inode_fsync_trans(handle, inode, 0);
4367
4368         map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
4369         map->m_pblk = pblk;
4370         map->m_len = ar.len;
4371         allocated = map->m_len;
4372         ext4_ext_show_leaf(inode, path);
4373 out:
4374         ext4_ext_drop_refs(path);
4375         kfree(path);
4376
4377         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4378                                        err ? err : allocated);
4379         return err ? err : allocated;
4380 }
4381
4382 int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4383 {
4384         struct super_block *sb = inode->i_sb;
4385         ext4_lblk_t last_block;
4386         int err = 0;
4387
4388         /*
4389          * TODO: optimization is possible here.
4390          * Probably we need not scan at all,
4391          * because page truncation is enough.
4392          */
4393
4394         /* we have to know where to truncate from in crash case */
4395         EXT4_I(inode)->i_disksize = inode->i_size;
4396         err = ext4_mark_inode_dirty(handle, inode);
4397         if (err)
4398                 return err;
4399
4400         last_block = (inode->i_size + sb->s_blocksize - 1)
4401                         >> EXT4_BLOCK_SIZE_BITS(sb);
4402 retry:
4403         err = ext4_es_remove_extent(inode, last_block,
4404                                     EXT_MAX_BLOCKS - last_block);
4405         if (err == -ENOMEM) {
4406                 memalloc_retry_wait(GFP_ATOMIC);
4407                 goto retry;
4408         }
4409         if (err)
4410                 return err;
4411 retry_remove_space:
4412         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4413         if (err == -ENOMEM) {
4414                 memalloc_retry_wait(GFP_ATOMIC);
4415                 goto retry_remove_space;
4416         }
4417         return err;
4418 }
4419
4420 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4421                                   ext4_lblk_t len, loff_t new_size,
4422                                   int flags)
4423 {
4424         struct inode *inode = file_inode(file);
4425         handle_t *handle;
4426         int ret = 0, ret2 = 0, ret3 = 0;
4427         int retries = 0;
4428         int depth = 0;
4429         struct ext4_map_blocks map;
4430         unsigned int credits;
4431         loff_t epos;
4432
4433         BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4434         map.m_lblk = offset;
4435         map.m_len = len;
4436         /*
4437          * Don't normalize the request if it can fit in one extent so
4438          * that it doesn't get unnecessarily split into multiple
4439          * extents.
4440          */
4441         if (len <= EXT_UNWRITTEN_MAX_LEN)
4442                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4443
4444         /*
4445          * credits to insert 1 extent into extent tree
4446          */
4447         credits = ext4_chunk_trans_blocks(inode, len);
4448         depth = ext_depth(inode);
4449
4450 retry:
4451         while (len) {
4452                 /*
4453                  * Recalculate credits when extent tree depth changes.
4454                  */
4455                 if (depth != ext_depth(inode)) {
4456                         credits = ext4_chunk_trans_blocks(inode, len);
4457                         depth = ext_depth(inode);
4458                 }
4459
4460                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4461                                             credits);
4462                 if (IS_ERR(handle)) {
4463                         ret = PTR_ERR(handle);
4464                         break;
4465                 }
4466                 ret = ext4_map_blocks(handle, inode, &map, flags);
4467                 if (ret <= 0) {
4468                         ext4_debug("inode #%lu: block %u: len %u: "
4469                                    "ext4_ext_map_blocks returned %d",
4470                                    inode->i_ino, map.m_lblk,
4471                                    map.m_len, ret);
4472                         ext4_mark_inode_dirty(handle, inode);
4473                         ext4_journal_stop(handle);
4474                         break;
4475                 }
4476                 /*
4477                  * allow a full retry cycle for any remaining allocations
4478                  */
4479                 retries = 0;
4480                 map.m_lblk += ret;
4481                 map.m_len = len = len - ret;
4482                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4483                 inode->i_ctime = current_time(inode);
4484                 if (new_size) {
4485                         if (epos > new_size)
4486                                 epos = new_size;
4487                         if (ext4_update_inode_size(inode, epos) & 0x1)
4488                                 inode->i_mtime = inode->i_ctime;
4489                 }
4490                 ret2 = ext4_mark_inode_dirty(handle, inode);
4491                 ext4_update_inode_fsync_trans(handle, inode, 1);
4492                 ret3 = ext4_journal_stop(handle);
4493                 ret2 = ret3 ? ret3 : ret2;
4494                 if (unlikely(ret2))
4495                         break;
4496         }
4497         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
4498                 goto retry;
4499
4500         return ret > 0 ? ret2 : ret;
4501 }
4502
4503 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);
4504
4505 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
4506
4507 static long ext4_zero_range(struct file *file, loff_t offset,
4508                             loff_t len, int mode)
4509 {
4510         struct inode *inode = file_inode(file);
4511         struct address_space *mapping = file->f_mapping;
4512         handle_t *handle = NULL;
4513         unsigned int max_blocks;
4514         loff_t new_size = 0;
4515         int ret = 0;
4516         int flags;
4517         int credits;
4518         int partial_begin, partial_end;
4519         loff_t start, end;
4520         ext4_lblk_t lblk;
4521         unsigned int blkbits = inode->i_blkbits;
4522
4523         trace_ext4_zero_range(inode, offset, len, mode);
4524
4525         /* Call ext4_force_commit to flush all data in case of data=journal. */
4526         if (ext4_should_journal_data(inode)) {
4527                 ret = ext4_force_commit(inode->i_sb);
4528                 if (ret)
4529                         return ret;
4530         }
4531
4532         /*
4533          * Round up offset. This is not fallocate, we need to zero out
4534          * blocks, so convert interior block aligned part of the range to
4535          * unwritten and possibly manually zero out unaligned parts of the
4536          * range.
4537          */
4538         start = round_up(offset, 1 << blkbits);
4539         end = round_down((offset + len), 1 << blkbits);
4540
4541         if (start < offset || end > offset + len)
4542                 return -EINVAL;
4543         partial_begin = offset & ((1 << blkbits) - 1);
4544         partial_end = (offset + len) & ((1 << blkbits) - 1);
4545
4546         lblk = start >> blkbits;
4547         max_blocks = (end >> blkbits);
4548         if (max_blocks < lblk)
4549                 max_blocks = 0;
4550         else
4551                 max_blocks -= lblk;
4552
4553         inode_lock(inode);
4554
4555         /*
4556          * Indirect files do not support unwritten extents
4557          */
4558         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4559                 ret = -EOPNOTSUPP;
4560                 goto out_mutex;
4561         }
4562
4563         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4564             (offset + len > inode->i_size ||
4565              offset + len > EXT4_I(inode)->i_disksize)) {
4566                 new_size = offset + len;
4567                 ret = inode_newsize_ok(inode, new_size);
4568                 if (ret)
4569                         goto out_mutex;
4570         }
4571
4572         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4573
4574         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4575         inode_dio_wait(inode);
4576
4577         ret = file_modified(file);
4578         if (ret)
4579                 goto out_mutex;
4580
4581         /* Preallocate the range including the unaligned edges */
4582         if (partial_begin || partial_end) {
4583                 ret = ext4_alloc_file_blocks(file,
4584                                 round_down(offset, 1 << blkbits) >> blkbits,
4585                                 (round_up((offset + len), 1 << blkbits) -
4586                                  round_down(offset, 1 << blkbits)) >> blkbits,
4587                                 new_size, flags);
4588                 if (ret)
4589                         goto out_mutex;
4590
4591         }
4592
4593         /* Zero range excluding the unaligned edges */
4594         if (max_blocks > 0) {
4595                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4596                           EXT4_EX_NOCACHE);
4597
4598                 /*
4599                  * Prevent page faults from reinstantiating pages we have
4600                  * released from page cache.
4601                  */
4602                 filemap_invalidate_lock(mapping);
4603
4604                 ret = ext4_break_layouts(inode);
4605                 if (ret) {
4606                         filemap_invalidate_unlock(mapping);
4607                         goto out_mutex;
4608                 }
4609
4610                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4611                 if (ret) {
4612                         filemap_invalidate_unlock(mapping);
4613                         goto out_mutex;
4614                 }
4615                 /* Now release the pages and zero block aligned part of pages */
4616                 truncate_pagecache_range(inode, start, end - 1);
4617                 inode->i_mtime = inode->i_ctime = current_time(inode);
4618
4619                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4620                                              flags);
4621                 filemap_invalidate_unlock(mapping);
4622                 if (ret)
4623                         goto out_mutex;
4624         }
4625         if (!partial_begin && !partial_end)
4626                 goto out_mutex;
4627
4628         /*
4629          * In worst case we have to writeout two nonadjacent unwritten
4630          * blocks and update the inode
4631          */
4632         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4633         if (ext4_should_journal_data(inode))
4634                 credits += 2;
4635         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4636         if (IS_ERR(handle)) {
4637                 ret = PTR_ERR(handle);
4638                 ext4_std_error(inode->i_sb, ret);
4639                 goto out_mutex;
4640         }
4641
4642         inode->i_mtime = inode->i_ctime = current_time(inode);
4643         if (new_size)
4644                 ext4_update_inode_size(inode, new_size);
4645         ret = ext4_mark_inode_dirty(handle, inode);
4646         if (unlikely(ret))
4647                 goto out_handle;
4648         /* Zero out partial block at the edges of the range */
4649         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4650         if (ret >= 0)
4651                 ext4_update_inode_fsync_trans(handle, inode, 1);
4652
4653         if (file->f_flags & O_SYNC)
4654                 ext4_handle_sync(handle);
4655
4656 out_handle:
4657         ext4_journal_stop(handle);
4658 out_mutex:
4659         inode_unlock(inode);
4660         return ret;
4661 }
4662
4663 /*
4664  * preallocate space for a file. This implements ext4's fallocate file
4665  * operation, which gets called from sys_fallocate system call.
4666  * For block-mapped files, posix_fallocate should fall back to the method
4667  * of writing zeroes to the required new blocks (the same behavior which is
4668  * expected for file systems which do not support fallocate() system call).
4669  */
4670 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4671 {
4672         struct inode *inode = file_inode(file);
4673         loff_t new_size = 0;
4674         unsigned int max_blocks;
4675         int ret = 0;
4676         int flags;
4677         ext4_lblk_t lblk;
4678         unsigned int blkbits = inode->i_blkbits;
4679
4680         /*
4681          * Encrypted inodes can't handle collapse range or insert
4682          * range since we would need to re-encrypt blocks with a
4683          * different IV or XTS tweak (which are based on the logical
4684          * block number).
4685          */
4686         if (IS_ENCRYPTED(inode) &&
4687             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
4688                 return -EOPNOTSUPP;
4689
4690         /* Return error if mode is not supported */
4691         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4692                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4693                      FALLOC_FL_INSERT_RANGE))
4694                 return -EOPNOTSUPP;
4695
4696         inode_lock(inode);
4697         ret = ext4_convert_inline_data(inode);
4698         inode_unlock(inode);
4699         if (ret)
4700                 goto exit;
4701
4702         if (mode & FALLOC_FL_PUNCH_HOLE) {
4703                 ret = ext4_punch_hole(file, offset, len);
4704                 goto exit;
4705         }
4706
4707         if (mode & FALLOC_FL_COLLAPSE_RANGE) {
4708                 ret = ext4_collapse_range(file, offset, len);
4709                 goto exit;
4710         }
4711
4712         if (mode & FALLOC_FL_INSERT_RANGE) {
4713                 ret = ext4_insert_range(file, offset, len);
4714                 goto exit;
4715         }
4716
4717         if (mode & FALLOC_FL_ZERO_RANGE) {
4718                 ret = ext4_zero_range(file, offset, len, mode);
4719                 goto exit;
4720         }
4721         trace_ext4_fallocate_enter(inode, offset, len, mode);
4722         lblk = offset >> blkbits;
4723
4724         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4725         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4726
4727         inode_lock(inode);
4728
4729         /*
4730          * We only support preallocation for extent-based files only
4731          */
4732         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4733                 ret = -EOPNOTSUPP;
4734                 goto out;
4735         }
4736
4737         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4738             (offset + len > inode->i_size ||
4739              offset + len > EXT4_I(inode)->i_disksize)) {
4740                 new_size = offset + len;
4741                 ret = inode_newsize_ok(inode, new_size);
4742                 if (ret)
4743                         goto out;
4744         }
4745
4746         /* Wait all existing dio workers, newcomers will block on i_rwsem */
4747         inode_dio_wait(inode);
4748
4749         ret = file_modified(file);
4750         if (ret)
4751                 goto out;
4752
4753         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4754         if (ret)
4755                 goto out;
4756
4757         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4758                 ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
4759                                         EXT4_I(inode)->i_sync_tid);
4760         }
4761 out:
4762         inode_unlock(inode);
4763         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4764 exit:
4765         return ret;
4766 }
4767
4768 /*
4769  * This function convert a range of blocks to written extents
4770  * The caller of this function will pass the start offset and the size.
4771  * all unwritten extents within this range will be converted to
4772  * written extents.
4773  *
4774  * This function is called from the direct IO end io call back
4775  * function, to convert the fallocated extents after IO is completed.
4776  * Returns 0 on success.
4777  */
4778 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4779                                    loff_t offset, ssize_t len)
4780 {
4781         unsigned int max_blocks;
4782         int ret = 0, ret2 = 0, ret3 = 0;
4783         struct ext4_map_blocks map;
4784         unsigned int blkbits = inode->i_blkbits;
4785         unsigned int credits = 0;
4786
4787         map.m_lblk = offset >> blkbits;
4788         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4789
4790         if (!handle) {
4791                 /*
4792                  * credits to insert 1 extent into extent tree
4793                  */
4794                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4795         }
4796         while (ret >= 0 && ret < max_blocks) {
4797                 map.m_lblk += ret;
4798                 map.m_len = (max_blocks -= ret);
4799                 if (credits) {
4800                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4801                                                     credits);
4802                         if (IS_ERR(handle)) {
4803                                 ret = PTR_ERR(handle);
4804                                 break;
4805                         }
4806                 }
4807                 ret = ext4_map_blocks(handle, inode, &map,
4808                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4809                 if (ret <= 0)
4810                         ext4_warning(inode->i_sb,
4811                                      "inode #%lu: block %u: len %u: "
4812                                      "ext4_ext_map_blocks returned %d",
4813                                      inode->i_ino, map.m_lblk,
4814                                      map.m_len, ret);
4815                 ret2 = ext4_mark_inode_dirty(handle, inode);
4816                 if (credits) {
4817                         ret3 = ext4_journal_stop(handle);
4818                         if (unlikely(ret3))
4819                                 ret2 = ret3;
4820                 }
4821
4822                 if (ret <= 0 || ret2)
4823                         break;
4824         }
4825         return ret > 0 ? ret2 : ret;
4826 }
4827
4828 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
4829 {
4830         int ret = 0, err = 0;
4831         struct ext4_io_end_vec *io_end_vec;
4832
4833         /*
4834          * This is somewhat ugly but the idea is clear: When transaction is
4835          * reserved, everything goes into it. Otherwise we rather start several
4836          * smaller transactions for conversion of each extent separately.
4837          */
4838         if (handle) {
4839                 handle = ext4_journal_start_reserved(handle,
4840                                                      EXT4_HT_EXT_CONVERT);
4841                 if (IS_ERR(handle))
4842                         return PTR_ERR(handle);
4843         }
4844
4845         list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4846                 ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4847                                                      io_end_vec->offset,
4848                                                      io_end_vec->size);
4849                 if (ret)
4850                         break;
4851         }
4852
4853         if (handle)
4854                 err = ext4_journal_stop(handle);
4855
4856         return ret < 0 ? ret : err;
4857 }
4858
4859 static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
4860 {
4861         __u64 physical = 0;
4862         __u64 length = 0;
4863         int blockbits = inode->i_sb->s_blocksize_bits;
4864         int error = 0;
4865         u16 iomap_type;
4866
4867         /* in-inode? */
4868         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4869                 struct ext4_iloc iloc;
4870                 int offset;     /* offset of xattr in inode */
4871
4872                 error = ext4_get_inode_loc(inode, &iloc);
4873                 if (error)
4874                         return error;
4875                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
4876                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4877                                 EXT4_I(inode)->i_extra_isize;
4878                 physical += offset;
4879                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4880                 brelse(iloc.bh);
4881                 iomap_type = IOMAP_INLINE;
4882         } else if (EXT4_I(inode)->i_file_acl) { /* external block */
4883                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4884                 length = inode->i_sb->s_blocksize;
4885                 iomap_type = IOMAP_MAPPED;
4886         } else {
4887                 /* no in-inode or external block for xattr, so return -ENOENT */
4888                 error = -ENOENT;
4889                 goto out;
4890         }
4891
4892         iomap->addr = physical;
4893         iomap->offset = 0;
4894         iomap->length = length;
4895         iomap->type = iomap_type;
4896         iomap->flags = 0;
4897 out:
4898         return error;
4899 }
4900
4901 static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
4902                                   loff_t length, unsigned flags,
4903                                   struct iomap *iomap, struct iomap *srcmap)
4904 {
4905         int error;
4906
4907         error = ext4_iomap_xattr_fiemap(inode, iomap);
4908         if (error == 0 && (offset >= iomap->length))
4909                 error = -ENOENT;
4910         return error;
4911 }
4912
4913 static const struct iomap_ops ext4_iomap_xattr_ops = {
4914         .iomap_begin            = ext4_iomap_xattr_begin,
4915 };
4916
4917 static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
4918 {
4919         u64 maxbytes;
4920
4921         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4922                 maxbytes = inode->i_sb->s_maxbytes;
4923         else
4924                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
4925
4926         if (*len == 0)
4927                 return -EINVAL;
4928         if (start > maxbytes)
4929                 return -EFBIG;
4930
4931         /*
4932          * Shrink request scope to what the fs can actually handle.
4933          */
4934         if (*len > maxbytes || (maxbytes - *len) < start)
4935                 *len = maxbytes - start;
4936         return 0;
4937 }
4938
4939 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4940                 u64 start, u64 len)
4941 {
4942         int error = 0;
4943
4944         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4945                 error = ext4_ext_precache(inode);
4946                 if (error)
4947                         return error;
4948                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4949         }
4950
4951         /*
4952          * For bitmap files the maximum size limit could be smaller than
4953          * s_maxbytes, so check len here manually instead of just relying on the
4954          * generic check.
4955          */
4956         error = ext4_fiemap_check_ranges(inode, start, &len);
4957         if (error)
4958                 return error;
4959
4960         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4961                 fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
4962                 return iomap_fiemap(inode, fieinfo, start, len,
4963                                     &ext4_iomap_xattr_ops);
4964         }
4965
4966         return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
4967 }
4968
4969 int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
4970                       __u64 start, __u64 len)
4971 {
4972         ext4_lblk_t start_blk, len_blks;
4973         __u64 last_blk;
4974         int error = 0;
4975
4976         if (ext4_has_inline_data(inode)) {
4977                 int has_inline;
4978
4979                 down_read(&EXT4_I(inode)->xattr_sem);
4980                 has_inline = ext4_has_inline_data(inode);
4981                 up_read(&EXT4_I(inode)->xattr_sem);
4982                 if (has_inline)
4983                         return 0;
4984         }
4985
4986         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4987                 error = ext4_ext_precache(inode);
4988                 if (error)
4989                         return error;
4990                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4991         }
4992
4993         error = fiemap_prep(inode, fieinfo, start, &len, 0);
4994         if (error)
4995                 return error;
4996
4997         error = ext4_fiemap_check_ranges(inode, start, &len);
4998         if (error)
4999                 return error;
5000
5001         start_blk = start >> inode->i_sb->s_blocksize_bits;
5002         last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5003         if (last_blk >= EXT_MAX_BLOCKS)
5004                 last_blk = EXT_MAX_BLOCKS-1;
5005         len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5006
5007         /*
5008          * Walk the extent tree gathering extent information
5009          * and pushing extents back to the user.
5010          */
5011         return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
5012 }
5013
5014 /*
5015  * ext4_ext_shift_path_extents:
5016  * Shift the extents of a path structure lying between path[depth].p_ext
5017  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5018  * if it is right shift or left shift operation.
5019  */
5020 static int
5021 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5022                             struct inode *inode, handle_t *handle,
5023                             enum SHIFT_DIRECTION SHIFT)
5024 {
5025         int depth, err = 0;
5026         struct ext4_extent *ex_start, *ex_last;
5027         bool update = false;
5028         int credits, restart_credits;
5029         depth = path->p_depth;
5030
5031         while (depth >= 0) {
5032                 if (depth == path->p_depth) {
5033                         ex_start = path[depth].p_ext;
5034                         if (!ex_start)
5035                                 return -EFSCORRUPTED;
5036
5037                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5038                         /* leaf + sb + inode */
5039                         credits = 3;
5040                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
5041                                 update = true;
5042                                 /* extent tree + sb + inode */
5043                                 credits = depth + 2;
5044                         }
5045
5046                         restart_credits = ext4_writepage_trans_blocks(inode);
5047                         err = ext4_datasem_ensure_credits(handle, inode, credits,
5048                                         restart_credits, 0);
5049                         if (err) {
5050                                 if (err > 0)
5051                                         err = -EAGAIN;
5052                                 goto out;
5053                         }
5054
5055                         err = ext4_ext_get_access(handle, inode, path + depth);
5056                         if (err)
5057                                 goto out;
5058
5059                         while (ex_start <= ex_last) {
5060                                 if (SHIFT == SHIFT_LEFT) {
5061                                         le32_add_cpu(&ex_start->ee_block,
5062                                                 -shift);
5063                                         /* Try to merge to the left. */
5064                                         if ((ex_start >
5065                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5066                                             &&
5067                                             ext4_ext_try_to_merge_right(inode,
5068                                             path, ex_start - 1))
5069                                                 ex_last--;
5070                                         else
5071                                                 ex_start++;
5072                                 } else {
5073                                         le32_add_cpu(&ex_last->ee_block, shift);
5074                                         ext4_ext_try_to_merge_right(inode, path,
5075                                                 ex_last);
5076                                         ex_last--;
5077                                 }
5078                         }
5079                         err = ext4_ext_dirty(handle, inode, path + depth);
5080                         if (err)
5081                                 goto out;
5082
5083                         if (--depth < 0 || !update)
5084                                 break;
5085                 }
5086
5087                 /* Update index too */
5088                 err = ext4_ext_get_access(handle, inode, path + depth);
5089                 if (err)
5090                         goto out;
5091
5092                 if (SHIFT == SHIFT_LEFT)
5093                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5094                 else
5095                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5096                 err = ext4_ext_dirty(handle, inode, path + depth);
5097                 if (err)
5098                         goto out;
5099
5100                 /* we are done if current index is not a starting index */
5101                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5102                         break;
5103
5104                 depth--;
5105         }
5106
5107 out:
5108         return err;
5109 }
5110
5111 /*
5112  * ext4_ext_shift_extents:
5113  * All the extents which lies in the range from @start to the last allocated
5114  * block for the @inode are shifted either towards left or right (depending
5115  * upon @SHIFT) by @shift blocks.
5116  * On success, 0 is returned, error otherwise.
5117  */
5118 static int
5119 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5120                        ext4_lblk_t start, ext4_lblk_t shift,
5121                        enum SHIFT_DIRECTION SHIFT)
5122 {
5123         struct ext4_ext_path *path;
5124         int ret = 0, depth;
5125         struct ext4_extent *extent;
5126         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5127         ext4_lblk_t tmp = EXT_MAX_BLOCKS;
5128
5129         /* Let path point to the last extent */
5130         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5131                                 EXT4_EX_NOCACHE);
5132         if (IS_ERR(path))
5133                 return PTR_ERR(path);
5134
5135         depth = path->p_depth;
5136         extent = path[depth].p_ext;
5137         if (!extent)
5138                 goto out;
5139
5140         stop = le32_to_cpu(extent->ee_block);
5141
5142        /*
5143         * For left shifts, make sure the hole on the left is big enough to
5144         * accommodate the shift.  For right shifts, make sure the last extent
5145         * won't be shifted beyond EXT_MAX_BLOCKS.
5146         */
5147         if (SHIFT == SHIFT_LEFT) {
5148                 path = ext4_find_extent(inode, start - 1, &path,
5149                                         EXT4_EX_NOCACHE);
5150                 if (IS_ERR(path))
5151                         return PTR_ERR(path);
5152                 depth = path->p_depth;
5153                 extent =  path[depth].p_ext;
5154                 if (extent) {
5155                         ex_start = le32_to_cpu(extent->ee_block);
5156                         ex_end = le32_to_cpu(extent->ee_block) +
5157                                 ext4_ext_get_actual_len(extent);
5158                 } else {
5159                         ex_start = 0;
5160                         ex_end = 0;
5161                 }
5162
5163                 if ((start == ex_start && shift > ex_start) ||
5164                     (shift > start - ex_end)) {
5165                         ret = -EINVAL;
5166                         goto out;
5167                 }
5168         } else {
5169                 if (shift > EXT_MAX_BLOCKS -
5170                     (stop + ext4_ext_get_actual_len(extent))) {
5171                         ret = -EINVAL;
5172                         goto out;
5173                 }
5174         }
5175
5176         /*
5177          * In case of left shift, iterator points to start and it is increased
5178          * till we reach stop. In case of right shift, iterator points to stop
5179          * and it is decreased till we reach start.
5180          */
5181 again:
5182         if (SHIFT == SHIFT_LEFT)
5183                 iterator = &start;
5184         else
5185                 iterator = &stop;
5186
5187         if (tmp != EXT_MAX_BLOCKS)
5188                 *iterator = tmp;
5189
5190         /*
5191          * Its safe to start updating extents.  Start and stop are unsigned, so
5192          * in case of right shift if extent with 0 block is reached, iterator
5193          * becomes NULL to indicate the end of the loop.
5194          */
5195         while (iterator && start <= stop) {
5196                 path = ext4_find_extent(inode, *iterator, &path,
5197                                         EXT4_EX_NOCACHE);
5198                 if (IS_ERR(path))
5199                         return PTR_ERR(path);
5200                 depth = path->p_depth;
5201                 extent = path[depth].p_ext;
5202                 if (!extent) {
5203                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5204                                          (unsigned long) *iterator);
5205                         return -EFSCORRUPTED;
5206                 }
5207                 if (SHIFT == SHIFT_LEFT && *iterator >
5208                     le32_to_cpu(extent->ee_block)) {
5209                         /* Hole, move to the next extent */
5210                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5211                                 path[depth].p_ext++;
5212                         } else {
5213                                 *iterator = ext4_ext_next_allocated_block(path);
5214                                 continue;
5215                         }
5216                 }
5217
5218                 tmp = *iterator;
5219                 if (SHIFT == SHIFT_LEFT) {
5220                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5221                         *iterator = le32_to_cpu(extent->ee_block) +
5222                                         ext4_ext_get_actual_len(extent);
5223                 } else {
5224                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5225                         if (le32_to_cpu(extent->ee_block) > 0)
5226                                 *iterator = le32_to_cpu(extent->ee_block) - 1;
5227                         else
5228                                 /* Beginning is reached, end of the loop */
5229                                 iterator = NULL;
5230                         /* Update path extent in case we need to stop */
5231                         while (le32_to_cpu(extent->ee_block) < start)
5232                                 extent++;
5233                         path[depth].p_ext = extent;
5234                 }
5235                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5236                                 handle, SHIFT);
5237                 /* iterator can be NULL which means we should break */
5238                 if (ret == -EAGAIN)
5239                         goto again;
5240                 if (ret)
5241                         break;
5242         }
5243 out:
5244         ext4_ext_drop_refs(path);
5245         kfree(path);
5246         return ret;
5247 }
5248
5249 /*
5250  * ext4_collapse_range:
5251  * This implements the fallocate's collapse range functionality for ext4
5252  * Returns: 0 and non-zero on error.
5253  */
5254 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)
5255 {
5256         struct inode *inode = file_inode(file);
5257         struct super_block *sb = inode->i_sb;
5258         struct address_space *mapping = inode->i_mapping;
5259         ext4_lblk_t punch_start, punch_stop;
5260         handle_t *handle;
5261         unsigned int credits;
5262         loff_t new_size, ioffset;
5263         int ret;
5264
5265         /*
5266          * We need to test this early because xfstests assumes that a
5267          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5268          * system does not support collapse range.
5269          */
5270         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5271                 return -EOPNOTSUPP;
5272
5273         /* Collapse range works only on fs cluster size aligned regions. */
5274         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5275                 return -EINVAL;
5276
5277         trace_ext4_collapse_range(inode, offset, len);
5278
5279         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5280         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5281
5282         /* Call ext4_force_commit to flush all data in case of data=journal. */
5283         if (ext4_should_journal_data(inode)) {
5284                 ret = ext4_force_commit(inode->i_sb);
5285                 if (ret)
5286                         return ret;
5287         }
5288
5289         inode_lock(inode);
5290         /*
5291          * There is no need to overlap collapse range with EOF, in which case
5292          * it is effectively a truncate operation
5293          */
5294         if (offset + len >= inode->i_size) {
5295                 ret = -EINVAL;
5296                 goto out_mutex;
5297         }
5298
5299         /* Currently just for extent based files */
5300         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5301                 ret = -EOPNOTSUPP;
5302                 goto out_mutex;
5303         }
5304
5305         /* Wait for existing dio to complete */
5306         inode_dio_wait(inode);
5307
5308         ret = file_modified(file);
5309         if (ret)
5310                 goto out_mutex;
5311
5312         /*
5313          * Prevent page faults from reinstantiating pages we have released from
5314          * page cache.
5315          */
5316         filemap_invalidate_lock(mapping);
5317
5318         ret = ext4_break_layouts(inode);
5319         if (ret)
5320                 goto out_mmap;
5321
5322         /*
5323          * Need to round down offset to be aligned with page size boundary
5324          * for page size > block size.
5325          */
5326         ioffset = round_down(offset, PAGE_SIZE);
5327         /*
5328          * Write tail of the last page before removed range since it will get
5329          * removed from the page cache below.
5330          */
5331         ret = filemap_write_and_wait_range(mapping, ioffset, offset);
5332         if (ret)
5333                 goto out_mmap;
5334         /*
5335          * Write data that will be shifted to preserve them when discarding
5336          * page cache below. We are also protected from pages becoming dirty
5337          * by i_rwsem and invalidate_lock.
5338          */
5339         ret = filemap_write_and_wait_range(mapping, offset + len,
5340                                            LLONG_MAX);
5341         if (ret)
5342                 goto out_mmap;
5343         truncate_pagecache(inode, ioffset);
5344
5345         credits = ext4_writepage_trans_blocks(inode);
5346         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5347         if (IS_ERR(handle)) {
5348                 ret = PTR_ERR(handle);
5349                 goto out_mmap;
5350         }
5351         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5352
5353         down_write(&EXT4_I(inode)->i_data_sem);
5354         ext4_discard_preallocations(inode, 0);
5355
5356         ret = ext4_es_remove_extent(inode, punch_start,
5357                                     EXT_MAX_BLOCKS - punch_start);
5358         if (ret) {
5359                 up_write(&EXT4_I(inode)->i_data_sem);
5360                 goto out_stop;
5361         }
5362
5363         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5364         if (ret) {
5365                 up_write(&EXT4_I(inode)->i_data_sem);
5366                 goto out_stop;
5367         }
5368         ext4_discard_preallocations(inode, 0);
5369
5370         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5371                                      punch_stop - punch_start, SHIFT_LEFT);
5372         if (ret) {
5373                 up_write(&EXT4_I(inode)->i_data_sem);
5374                 goto out_stop;
5375         }
5376
5377         new_size = inode->i_size - len;
5378         i_size_write(inode, new_size);
5379         EXT4_I(inode)->i_disksize = new_size;
5380
5381         up_write(&EXT4_I(inode)->i_data_sem);
5382         if (IS_SYNC(inode))
5383                 ext4_handle_sync(handle);
5384         inode->i_mtime = inode->i_ctime = current_time(inode);
5385         ret = ext4_mark_inode_dirty(handle, inode);
5386         ext4_update_inode_fsync_trans(handle, inode, 1);
5387
5388 out_stop:
5389         ext4_journal_stop(handle);
5390 out_mmap:
5391         filemap_invalidate_unlock(mapping);
5392 out_mutex:
5393         inode_unlock(inode);
5394         return ret;
5395 }
5396
5397 /*
5398  * ext4_insert_range:
5399  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5400  * The data blocks starting from @offset to the EOF are shifted by @len
5401  * towards right to create a hole in the @inode. Inode size is increased
5402  * by len bytes.
5403  * Returns 0 on success, error otherwise.
5404  */
5405 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
5406 {
5407         struct inode *inode = file_inode(file);
5408         struct super_block *sb = inode->i_sb;
5409         struct address_space *mapping = inode->i_mapping;
5410         handle_t *handle;
5411         struct ext4_ext_path *path;
5412         struct ext4_extent *extent;
5413         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5414         unsigned int credits, ee_len;
5415         int ret = 0, depth, split_flag = 0;
5416         loff_t ioffset;
5417
5418         /*
5419          * We need to test this early because xfstests assumes that an
5420          * insert range of (0, 1) will return EOPNOTSUPP if the file
5421          * system does not support insert range.
5422          */
5423         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5424                 return -EOPNOTSUPP;
5425
5426         /* Insert range works only on fs cluster size aligned regions. */
5427         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5428                 return -EINVAL;
5429
5430         trace_ext4_insert_range(inode, offset, len);
5431
5432         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5433         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5434
5435         /* Call ext4_force_commit to flush all data in case of data=journal */
5436         if (ext4_should_journal_data(inode)) {
5437                 ret = ext4_force_commit(inode->i_sb);
5438                 if (ret)
5439                         return ret;
5440         }
5441
5442         inode_lock(inode);
5443         /* Currently just for extent based files */
5444         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5445                 ret = -EOPNOTSUPP;
5446                 goto out_mutex;
5447         }
5448
5449         /* Check whether the maximum file size would be exceeded */
5450         if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5451                 ret = -EFBIG;
5452                 goto out_mutex;
5453         }
5454
5455         /* Offset must be less than i_size */
5456         if (offset >= inode->i_size) {
5457                 ret = -EINVAL;
5458                 goto out_mutex;
5459         }
5460
5461         /* Wait for existing dio to complete */
5462         inode_dio_wait(inode);
5463
5464         ret = file_modified(file);
5465         if (ret)
5466                 goto out_mutex;
5467
5468         /*
5469          * Prevent page faults from reinstantiating pages we have released from
5470          * page cache.
5471          */
5472         filemap_invalidate_lock(mapping);
5473
5474         ret = ext4_break_layouts(inode);
5475         if (ret)
5476                 goto out_mmap;
5477
5478         /*
5479          * Need to round down to align start offset to page size boundary
5480          * for page size > block size.
5481          */
5482         ioffset = round_down(offset, PAGE_SIZE);
5483         /* Write out all dirty pages */
5484         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5485                         LLONG_MAX);
5486         if (ret)
5487                 goto out_mmap;
5488         truncate_pagecache(inode, ioffset);
5489
5490         credits = ext4_writepage_trans_blocks(inode);
5491         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5492         if (IS_ERR(handle)) {
5493                 ret = PTR_ERR(handle);
5494                 goto out_mmap;
5495         }
5496         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5497
5498         /* Expand file to avoid data loss if there is error while shifting */
5499         inode->i_size += len;
5500         EXT4_I(inode)->i_disksize += len;
5501         inode->i_mtime = inode->i_ctime = current_time(inode);
5502         ret = ext4_mark_inode_dirty(handle, inode);
5503         if (ret)
5504                 goto out_stop;
5505
5506         down_write(&EXT4_I(inode)->i_data_sem);
5507         ext4_discard_preallocations(inode, 0);
5508
5509         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5510         if (IS_ERR(path)) {
5511                 up_write(&EXT4_I(inode)->i_data_sem);
5512                 goto out_stop;
5513         }
5514
5515         depth = ext_depth(inode);
5516         extent = path[depth].p_ext;
5517         if (extent) {
5518                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5519                 ee_len = ext4_ext_get_actual_len(extent);
5520
5521                 /*
5522                  * If offset_lblk is not the starting block of extent, split
5523                  * the extent @offset_lblk
5524                  */
5525                 if ((offset_lblk > ee_start_lblk) &&
5526                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5527                         if (ext4_ext_is_unwritten(extent))
5528                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5529                                         EXT4_EXT_MARK_UNWRIT2;
5530                         ret = ext4_split_extent_at(handle, inode, &path,
5531                                         offset_lblk, split_flag,
5532                                         EXT4_EX_NOCACHE |
5533                                         EXT4_GET_BLOCKS_PRE_IO |
5534                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5535                 }
5536
5537                 ext4_ext_drop_refs(path);
5538                 kfree(path);
5539                 if (ret < 0) {
5540                         up_write(&EXT4_I(inode)->i_data_sem);
5541                         goto out_stop;
5542                 }
5543         } else {
5544                 ext4_ext_drop_refs(path);
5545                 kfree(path);
5546         }
5547
5548         ret = ext4_es_remove_extent(inode, offset_lblk,
5549                         EXT_MAX_BLOCKS - offset_lblk);
5550         if (ret) {
5551                 up_write(&EXT4_I(inode)->i_data_sem);
5552                 goto out_stop;
5553         }
5554
5555         /*
5556          * if offset_lblk lies in a hole which is at start of file, use
5557          * ee_start_lblk to shift extents
5558          */
5559         ret = ext4_ext_shift_extents(inode, handle,
5560                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5561                 len_lblk, SHIFT_RIGHT);
5562
5563         up_write(&EXT4_I(inode)->i_data_sem);
5564         if (IS_SYNC(inode))
5565                 ext4_handle_sync(handle);
5566         if (ret >= 0)
5567                 ext4_update_inode_fsync_trans(handle, inode, 1);
5568
5569 out_stop:
5570         ext4_journal_stop(handle);
5571 out_mmap:
5572         filemap_invalidate_unlock(mapping);
5573 out_mutex:
5574         inode_unlock(inode);
5575         return ret;
5576 }
5577
5578 /**
5579  * ext4_swap_extents() - Swap extents between two inodes
5580  * @handle: handle for this transaction
5581  * @inode1:     First inode
5582  * @inode2:     Second inode
5583  * @lblk1:      Start block for first inode
5584  * @lblk2:      Start block for second inode
5585  * @count:      Number of blocks to swap
5586  * @unwritten: Mark second inode's extents as unwritten after swap
5587  * @erp:        Pointer to save error value
5588  *
5589  * This helper routine does exactly what is promise "swap extents". All other
5590  * stuff such as page-cache locking consistency, bh mapping consistency or
5591  * extent's data copying must be performed by caller.
5592  * Locking:
5593  *              i_rwsem is held for both inodes
5594  *              i_data_sem is locked for write for both inodes
5595  * Assumptions:
5596  *              All pages from requested range are locked for both inodes
5597  */
5598 int
5599 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5600                   struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5601                   ext4_lblk_t count, int unwritten, int *erp)
5602 {
5603         struct ext4_ext_path *path1 = NULL;
5604         struct ext4_ext_path *path2 = NULL;
5605         int replaced_count = 0;
5606
5607         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5608         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5609         BUG_ON(!inode_is_locked(inode1));
5610         BUG_ON(!inode_is_locked(inode2));
5611
5612         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5613         if (unlikely(*erp))
5614                 return 0;
5615         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5616         if (unlikely(*erp))
5617                 return 0;
5618
5619         while (count) {
5620                 struct ext4_extent *ex1, *ex2, tmp_ex;
5621                 ext4_lblk_t e1_blk, e2_blk;
5622                 int e1_len, e2_len, len;
5623                 int split = 0;
5624
5625                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5626                 if (IS_ERR(path1)) {
5627                         *erp = PTR_ERR(path1);
5628                         path1 = NULL;
5629                 finish:
5630                         count = 0;
5631                         goto repeat;
5632                 }
5633                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5634                 if (IS_ERR(path2)) {
5635                         *erp = PTR_ERR(path2);
5636                         path2 = NULL;
5637                         goto finish;
5638                 }
5639                 ex1 = path1[path1->p_depth].p_ext;
5640                 ex2 = path2[path2->p_depth].p_ext;
5641                 /* Do we have something to swap ? */
5642                 if (unlikely(!ex2 || !ex1))
5643                         goto finish;
5644
5645                 e1_blk = le32_to_cpu(ex1->ee_block);
5646                 e2_blk = le32_to_cpu(ex2->ee_block);
5647                 e1_len = ext4_ext_get_actual_len(ex1);
5648                 e2_len = ext4_ext_get_actual_len(ex2);
5649
5650                 /* Hole handling */
5651                 if (!in_range(lblk1, e1_blk, e1_len) ||
5652                     !in_range(lblk2, e2_blk, e2_len)) {
5653                         ext4_lblk_t next1, next2;
5654
5655                         /* if hole after extent, then go to next extent */
5656                         next1 = ext4_ext_next_allocated_block(path1);
5657                         next2 = ext4_ext_next_allocated_block(path2);
5658                         /* If hole before extent, then shift to that extent */
5659                         if (e1_blk > lblk1)
5660                                 next1 = e1_blk;
5661                         if (e2_blk > lblk2)
5662                                 next2 = e2_blk;
5663                         /* Do we have something to swap */
5664                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5665                                 goto finish;
5666                         /* Move to the rightest boundary */
5667                         len = next1 - lblk1;
5668                         if (len < next2 - lblk2)
5669                                 len = next2 - lblk2;
5670                         if (len > count)
5671                                 len = count;
5672                         lblk1 += len;
5673                         lblk2 += len;
5674                         count -= len;
5675                         goto repeat;
5676                 }
5677
5678                 /* Prepare left boundary */
5679                 if (e1_blk < lblk1) {
5680                         split = 1;
5681                         *erp = ext4_force_split_extent_at(handle, inode1,
5682                                                 &path1, lblk1, 0);
5683                         if (unlikely(*erp))
5684                                 goto finish;
5685                 }
5686                 if (e2_blk < lblk2) {
5687                         split = 1;
5688                         *erp = ext4_force_split_extent_at(handle, inode2,
5689                                                 &path2,  lblk2, 0);
5690                         if (unlikely(*erp))
5691                                 goto finish;
5692                 }
5693                 /* ext4_split_extent_at() may result in leaf extent split,
5694                  * path must to be revalidated. */
5695                 if (split)
5696                         goto repeat;
5697
5698                 /* Prepare right boundary */
5699                 len = count;
5700                 if (len > e1_blk + e1_len - lblk1)
5701                         len = e1_blk + e1_len - lblk1;
5702                 if (len > e2_blk + e2_len - lblk2)
5703                         len = e2_blk + e2_len - lblk2;
5704
5705                 if (len != e1_len) {
5706                         split = 1;
5707                         *erp = ext4_force_split_extent_at(handle, inode1,
5708                                                 &path1, lblk1 + len, 0);
5709                         if (unlikely(*erp))
5710                                 goto finish;
5711                 }
5712                 if (len != e2_len) {
5713                         split = 1;
5714                         *erp = ext4_force_split_extent_at(handle, inode2,
5715                                                 &path2, lblk2 + len, 0);
5716                         if (*erp)
5717                                 goto finish;
5718                 }
5719                 /* ext4_split_extent_at() may result in leaf extent split,
5720                  * path must to be revalidated. */
5721                 if (split)
5722                         goto repeat;
5723
5724                 BUG_ON(e2_len != e1_len);
5725                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5726                 if (unlikely(*erp))
5727                         goto finish;
5728                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5729                 if (unlikely(*erp))
5730                         goto finish;
5731
5732                 /* Both extents are fully inside boundaries. Swap it now */
5733                 tmp_ex = *ex1;
5734                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5735                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5736                 ex1->ee_len = cpu_to_le16(e2_len);
5737                 ex2->ee_len = cpu_to_le16(e1_len);
5738                 if (unwritten)
5739                         ext4_ext_mark_unwritten(ex2);
5740                 if (ext4_ext_is_unwritten(&tmp_ex))
5741                         ext4_ext_mark_unwritten(ex1);
5742
5743                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5744                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5745                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5746                                       path2->p_depth);
5747                 if (unlikely(*erp))
5748                         goto finish;
5749                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5750                                       path1->p_depth);
5751                 /*
5752                  * Looks scarry ah..? second inode already points to new blocks,
5753                  * and it was successfully dirtied. But luckily error may happen
5754                  * only due to journal error, so full transaction will be
5755                  * aborted anyway.
5756                  */
5757                 if (unlikely(*erp))
5758                         goto finish;
5759                 lblk1 += len;
5760                 lblk2 += len;
5761                 replaced_count += len;
5762                 count -= len;
5763
5764         repeat:
5765                 ext4_ext_drop_refs(path1);
5766                 kfree(path1);
5767                 ext4_ext_drop_refs(path2);
5768                 kfree(path2);
5769                 path1 = path2 = NULL;
5770         }
5771         return replaced_count;
5772 }
5773
5774 /*
5775  * ext4_clu_mapped - determine whether any block in a logical cluster has
5776  *                   been mapped to a physical cluster
5777  *
5778  * @inode - file containing the logical cluster
5779  * @lclu - logical cluster of interest
5780  *
5781  * Returns 1 if any block in the logical cluster is mapped, signifying
5782  * that a physical cluster has been allocated for it.  Otherwise,
5783  * returns 0.  Can also return negative error codes.  Derived from
5784  * ext4_ext_map_blocks().
5785  */
5786 int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5787 {
5788         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5789         struct ext4_ext_path *path;
5790         int depth, mapped = 0, err = 0;
5791         struct ext4_extent *extent;
5792         ext4_lblk_t first_lblk, first_lclu, last_lclu;
5793
5794         /* search for the extent closest to the first block in the cluster */
5795         path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5796         if (IS_ERR(path)) {
5797                 err = PTR_ERR(path);
5798                 path = NULL;
5799                 goto out;
5800         }
5801
5802         depth = ext_depth(inode);
5803
5804         /*
5805          * A consistent leaf must not be empty.  This situation is possible,
5806          * though, _during_ tree modification, and it's why an assert can't
5807          * be put in ext4_find_extent().
5808          */
5809         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5810                 EXT4_ERROR_INODE(inode,
5811                     "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5812                                  (unsigned long) EXT4_C2B(sbi, lclu),
5813                                  depth, path[depth].p_block);
5814                 err = -EFSCORRUPTED;
5815                 goto out;
5816         }
5817
5818         extent = path[depth].p_ext;
5819
5820         /* can't be mapped if the extent tree is empty */
5821         if (extent == NULL)
5822                 goto out;
5823
5824         first_lblk = le32_to_cpu(extent->ee_block);
5825         first_lclu = EXT4_B2C(sbi, first_lblk);
5826
5827         /*
5828          * Three possible outcomes at this point - found extent spanning
5829          * the target cluster, to the left of the target cluster, or to the
5830          * right of the target cluster.  The first two cases are handled here.
5831          * The last case indicates the target cluster is not mapped.
5832          */
5833         if (lclu >= first_lclu) {
5834                 last_lclu = EXT4_B2C(sbi, first_lblk +
5835                                      ext4_ext_get_actual_len(extent) - 1);
5836                 if (lclu <= last_lclu) {
5837                         mapped = 1;
5838                 } else {
5839                         first_lblk = ext4_ext_next_allocated_block(path);
5840                         first_lclu = EXT4_B2C(sbi, first_lblk);
5841                         if (lclu == first_lclu)
5842                                 mapped = 1;
5843                 }
5844         }
5845
5846 out:
5847         ext4_ext_drop_refs(path);
5848         kfree(path);
5849
5850         return err ? err : mapped;
5851 }
5852
5853 /*
5854  * Updates physical block address and unwritten status of extent
5855  * starting at lblk start and of len. If such an extent doesn't exist,
5856  * this function splits the extent tree appropriately to create an
5857  * extent like this.  This function is called in the fast commit
5858  * replay path.  Returns 0 on success and error on failure.
5859  */
5860 int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
5861                               int len, int unwritten, ext4_fsblk_t pblk)
5862 {
5863         struct ext4_ext_path *path = NULL, *ppath;
5864         struct ext4_extent *ex;
5865         int ret;
5866
5867         path = ext4_find_extent(inode, start, NULL, 0);
5868         if (IS_ERR(path))
5869                 return PTR_ERR(path);
5870         ex = path[path->p_depth].p_ext;
5871         if (!ex) {
5872                 ret = -EFSCORRUPTED;
5873                 goto out;
5874         }
5875
5876         if (le32_to_cpu(ex->ee_block) != start ||
5877                 ext4_ext_get_actual_len(ex) != len) {
5878                 /* We need to split this extent to match our extent first */
5879                 ppath = path;
5880                 down_write(&EXT4_I(inode)->i_data_sem);
5881                 ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
5882                 up_write(&EXT4_I(inode)->i_data_sem);
5883                 if (ret)
5884                         goto out;
5885                 kfree(path);
5886                 path = ext4_find_extent(inode, start, NULL, 0);
5887                 if (IS_ERR(path))
5888                         return -1;
5889                 ppath = path;
5890                 ex = path[path->p_depth].p_ext;
5891                 WARN_ON(le32_to_cpu(ex->ee_block) != start);
5892                 if (ext4_ext_get_actual_len(ex) != len) {
5893                         down_write(&EXT4_I(inode)->i_data_sem);
5894                         ret = ext4_force_split_extent_at(NULL, inode, &ppath,
5895                                                          start + len, 1);
5896                         up_write(&EXT4_I(inode)->i_data_sem);
5897                         if (ret)
5898                                 goto out;
5899                         kfree(path);
5900                         path = ext4_find_extent(inode, start, NULL, 0);
5901                         if (IS_ERR(path))
5902                                 return -EINVAL;
5903                         ex = path[path->p_depth].p_ext;
5904                 }
5905         }
5906         if (unwritten)
5907                 ext4_ext_mark_unwritten(ex);
5908         else
5909                 ext4_ext_mark_initialized(ex);
5910         ext4_ext_store_pblock(ex, pblk);
5911         down_write(&EXT4_I(inode)->i_data_sem);
5912         ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5913         up_write(&EXT4_I(inode)->i_data_sem);
5914 out:
5915         ext4_ext_drop_refs(path);
5916         kfree(path);
5917         ext4_mark_inode_dirty(NULL, inode);
5918         return ret;
5919 }
5920
5921 /* Try to shrink the extent tree */
5922 void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
5923 {
5924         struct ext4_ext_path *path = NULL;
5925         struct ext4_extent *ex;
5926         ext4_lblk_t old_cur, cur = 0;
5927
5928         while (cur < end) {
5929                 path = ext4_find_extent(inode, cur, NULL, 0);
5930                 if (IS_ERR(path))
5931                         return;
5932                 ex = path[path->p_depth].p_ext;
5933                 if (!ex) {
5934                         ext4_ext_drop_refs(path);
5935                         kfree(path);
5936                         ext4_mark_inode_dirty(NULL, inode);
5937                         return;
5938                 }
5939                 old_cur = cur;
5940                 cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5941                 if (cur <= old_cur)
5942                         cur = old_cur + 1;
5943                 ext4_ext_try_to_merge(NULL, inode, path, ex);
5944                 down_write(&EXT4_I(inode)->i_data_sem);
5945                 ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5946                 up_write(&EXT4_I(inode)->i_data_sem);
5947                 ext4_mark_inode_dirty(NULL, inode);
5948                 ext4_ext_drop_refs(path);
5949                 kfree(path);
5950         }
5951 }
5952
5953 /* Check if *cur is a hole and if it is, skip it */
5954 static int skip_hole(struct inode *inode, ext4_lblk_t *cur)
5955 {
5956         int ret;
5957         struct ext4_map_blocks map;
5958
5959         map.m_lblk = *cur;
5960         map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
5961
5962         ret = ext4_map_blocks(NULL, inode, &map, 0);
5963         if (ret < 0)
5964                 return ret;
5965         if (ret != 0)
5966                 return 0;
5967         *cur = *cur + map.m_len;
5968         return 0;
5969 }
5970
5971 /* Count number of blocks used by this inode and update i_blocks */
5972 int ext4_ext_replay_set_iblocks(struct inode *inode)
5973 {
5974         struct ext4_ext_path *path = NULL, *path2 = NULL;
5975         struct ext4_extent *ex;
5976         ext4_lblk_t cur = 0, end;
5977         int numblks = 0, i, ret = 0;
5978         ext4_fsblk_t cmp1, cmp2;
5979         struct ext4_map_blocks map;
5980
5981         /* Determin the size of the file first */
5982         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5983                                         EXT4_EX_NOCACHE);
5984         if (IS_ERR(path))
5985                 return PTR_ERR(path);
5986         ex = path[path->p_depth].p_ext;
5987         if (!ex) {
5988                 ext4_ext_drop_refs(path);
5989                 kfree(path);
5990                 goto out;
5991         }
5992         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5993         ext4_ext_drop_refs(path);
5994         kfree(path);
5995
5996         /* Count the number of data blocks */
5997         cur = 0;
5998         while (cur < end) {
5999                 map.m_lblk = cur;
6000                 map.m_len = end - cur;
6001                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6002                 if (ret < 0)
6003                         break;
6004                 if (ret > 0)
6005                         numblks += ret;
6006                 cur = cur + map.m_len;
6007         }
6008
6009         /*
6010          * Count the number of extent tree blocks. We do it by looking up
6011          * two successive extents and determining the difference between
6012          * their paths. When path is different for 2 successive extents
6013          * we compare the blocks in the path at each level and increment
6014          * iblocks by total number of differences found.
6015          */
6016         cur = 0;
6017         ret = skip_hole(inode, &cur);
6018         if (ret < 0)
6019                 goto out;
6020         path = ext4_find_extent(inode, cur, NULL, 0);
6021         if (IS_ERR(path))
6022                 goto out;
6023         numblks += path->p_depth;
6024         ext4_ext_drop_refs(path);
6025         kfree(path);
6026         while (cur < end) {
6027                 path = ext4_find_extent(inode, cur, NULL, 0);
6028                 if (IS_ERR(path))
6029                         break;
6030                 ex = path[path->p_depth].p_ext;
6031                 if (!ex) {
6032                         ext4_ext_drop_refs(path);
6033                         kfree(path);
6034                         return 0;
6035                 }
6036                 cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
6037                                         ext4_ext_get_actual_len(ex));
6038                 ret = skip_hole(inode, &cur);
6039                 if (ret < 0) {
6040                         ext4_ext_drop_refs(path);
6041                         kfree(path);
6042                         break;
6043                 }
6044                 path2 = ext4_find_extent(inode, cur, NULL, 0);
6045                 if (IS_ERR(path2)) {
6046                         ext4_ext_drop_refs(path);
6047                         kfree(path);
6048                         break;
6049                 }
6050                 for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
6051                         cmp1 = cmp2 = 0;
6052                         if (i <= path->p_depth)
6053                                 cmp1 = path[i].p_bh ?
6054                                         path[i].p_bh->b_blocknr : 0;
6055                         if (i <= path2->p_depth)
6056                                 cmp2 = path2[i].p_bh ?
6057                                         path2[i].p_bh->b_blocknr : 0;
6058                         if (cmp1 != cmp2 && cmp2 != 0)
6059                                 numblks++;
6060                 }
6061                 ext4_ext_drop_refs(path);
6062                 ext4_ext_drop_refs(path2);
6063                 kfree(path);
6064                 kfree(path2);
6065         }
6066
6067 out:
6068         inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
6069         ext4_mark_inode_dirty(NULL, inode);
6070         return 0;
6071 }
6072
6073 int ext4_ext_clear_bb(struct inode *inode)
6074 {
6075         struct ext4_ext_path *path = NULL;
6076         struct ext4_extent *ex;
6077         ext4_lblk_t cur = 0, end;
6078         int j, ret = 0;
6079         struct ext4_map_blocks map;
6080
6081         if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA))
6082                 return 0;
6083
6084         /* Determin the size of the file first */
6085         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6086                                         EXT4_EX_NOCACHE);
6087         if (IS_ERR(path))
6088                 return PTR_ERR(path);
6089         ex = path[path->p_depth].p_ext;
6090         if (!ex) {
6091                 ext4_ext_drop_refs(path);
6092                 kfree(path);
6093                 return 0;
6094         }
6095         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6096         ext4_ext_drop_refs(path);
6097         kfree(path);
6098
6099         cur = 0;
6100         while (cur < end) {
6101                 map.m_lblk = cur;
6102                 map.m_len = end - cur;
6103                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6104                 if (ret < 0)
6105                         break;
6106                 if (ret > 0) {
6107                         path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
6108                         if (!IS_ERR_OR_NULL(path)) {
6109                                 for (j = 0; j < path->p_depth; j++) {
6110
6111                                         ext4_mb_mark_bb(inode->i_sb,
6112                                                         path[j].p_block, 1, 0);
6113                                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6114                                                         0, path[j].p_block, 1, 1);
6115                                 }
6116                                 ext4_ext_drop_refs(path);
6117                                 kfree(path);
6118                         }
6119                         ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
6120                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6121                                         map.m_lblk, map.m_pblk, map.m_len, 1);
6122                 }
6123                 cur = cur + map.m_len;
6124         }
6125
6126         return 0;
6127 }