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/backing-dev.h>
  31 #include <linux/iomap.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_mutex. 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, path->p_bh);
 145                 /*
 146                  * The extent buffer's verified bit will be set again in
 147                  * __ext4_ext_dirty(). We could leave an inconsistent
 148                  * buffer if the extents updating procudure break off du
 149                  * to some error happens, force to check it again.
 150                  */
 151                 if (!err)
 152                         clear_buffer_verified(path->p_bh);
 153         }
 154         /* path points to leaf/index in inode body */
 155         /* we use in-core data, no need to protect them */
 156         return err;
 157 }
 158
 159 /*
 160  * could return:
 161  *  - EROFS
 162  *  - ENOMEM
 163  *  - EIO
 164  */
 165 static int __ext4_ext_dirty(const char *where, unsigned int line,
 166                             handle_t *handle, struct inode *inode,
 167                             struct ext4_ext_path *path)
 168 {
 169         int err;
 170
 171         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 172         if (path->p_bh) {
 173                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 174                 /* path points to block */
 175                 err = __ext4_handle_dirty_metadata(where, line, handle,
 176                                                    inode, path->p_bh);
 177                 /* Extents updating done, re-set verified flag */
 178                 if (!err)
 179                         set_buffer_verified(path->p_bh);
 180         } else {
 181                 /* path points to leaf/index in inode body */
 182                 err = ext4_mark_inode_dirty(handle, inode);
 183         }
 184         return err;
 185 }
 186
 187 #define ext4_ext_dirty(handle, inode, path) \
 188                 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
 189
 190 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 191                               struct ext4_ext_path *path,
 192                               ext4_lblk_t block)
 193 {
 194         if (path) {
 195                 int depth = path->p_depth;
 196                 struct ext4_extent *ex;
 197
 198                 /*
 199                  * Try to predict block placement assuming that we are
 200                  * filling in a file which will eventually be
 201                  * non-sparse --- i.e., in the case of libbfd writing
 202                  * an ELF object sections out-of-order but in a way
 203                  * the eventually results in a contiguous object or
 204                  * executable file, or some database extending a table
 205                  * space file.  However, this is actually somewhat
 206                  * non-ideal if we are writing a sparse file such as
 207                  * qemu or KVM writing a raw image file that is going
 208                  * to stay fairly sparse, since it will end up
 209                  * fragmenting the file system's free space.  Maybe we
 210                  * should have some hueristics or some way to allow
 211                  * userspace to pass a hint to file system,
 212                  * especially if the latter case turns out to be
 213                  * common.
 214                  */
 215                 ex = path[depth].p_ext;
 216                 if (ex) {
 217                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 218                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 219
 220                         if (block > ext_block)
 221                                 return ext_pblk + (block - ext_block);
 222                         else
 223                                 return ext_pblk - (ext_block - block);
 224                 }
 225
 226                 /* it looks like index is empty;
 227                  * try to find starting block from index itself */
 228                 if (path[depth].p_bh)
 229                         return path[depth].p_bh->b_blocknr;
 230         }
 231
 232         /* OK. use inode's group */
 233         return ext4_inode_to_goal_block(inode);
 234 }
 235
 236 /*
 237  * Allocation for a meta data block
 238  */
 239 static ext4_fsblk_t
 240 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 241                         struct ext4_ext_path *path,
 242                         struct ext4_extent *ex, int *err, unsigned int flags)
 243 {
 244         ext4_fsblk_t goal, newblock;
 245
 246         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 247         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 248                                         NULL, err);
 249         return newblock;
 250 }
 251
 252 static inline int ext4_ext_space_block(struct inode *inode, int check)
 253 {
 254         int size;
 255
 256         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 257                         / sizeof(struct ext4_extent);
 258 #ifdef AGGRESSIVE_TEST
 259         if (!check && size > 6)
 260                 size = 6;
 261 #endif
 262         return size;
 263 }
 264
 265 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 266 {
 267         int size;
 268
 269         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 270                         / sizeof(struct ext4_extent_idx);
 271 #ifdef AGGRESSIVE_TEST
 272         if (!check && size > 5)
 273                 size = 5;
 274 #endif
 275         return size;
 276 }
 277
 278 static inline int ext4_ext_space_root(struct inode *inode, int check)
 279 {
 280         int size;
 281
 282         size = sizeof(EXT4_I(inode)->i_data);
 283         size -= sizeof(struct ext4_extent_header);
 284         size /= sizeof(struct ext4_extent);
 285 #ifdef AGGRESSIVE_TEST
 286         if (!check && size > 3)
 287                 size = 3;
 288 #endif
 289         return size;
 290 }
 291
 292 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 293 {
 294         int size;
 295
 296         size = sizeof(EXT4_I(inode)->i_data);
 297         size -= sizeof(struct ext4_extent_header);
 298         size /= sizeof(struct ext4_extent_idx);
 299 #ifdef AGGRESSIVE_TEST
 300         if (!check && size > 4)
 301                 size = 4;
 302 #endif
 303         return size;
 304 }
 305
 306 static inline int
 307 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 308                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 309                            int nofail)
 310 {
 311         struct ext4_ext_path *path = *ppath;
 312         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 313         int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO;
 314
 315         if (nofail)
 316                 flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL;
 317
 318         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 319                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 320                         flags);
 321 }
 322
 323 static int
 324 ext4_ext_max_entries(struct inode *inode, int depth)
 325 {
 326         int max;
 327
 328         if (depth == ext_depth(inode)) {
 329                 if (depth == 0)
 330                         max = ext4_ext_space_root(inode, 1);
 331                 else
 332                         max = ext4_ext_space_root_idx(inode, 1);
 333         } else {
 334                 if (depth == 0)
 335                         max = ext4_ext_space_block(inode, 1);
 336                 else
 337                         max = ext4_ext_space_block_idx(inode, 1);
 338         }
 339
 340         return max;
 341 }
 342
 343 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 344 {
 345         ext4_fsblk_t block = ext4_ext_pblock(ext);
 346         int len = ext4_ext_get_actual_len(ext);
 347         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 348
 349         /*
 350          * We allow neither:
 351          *  - zero length
 352          *  - overflow/wrap-around
 353          */
 354         if (lblock + len <= lblock)
 355                 return 0;
 356         return ext4_inode_block_valid(inode, block, len);
 357 }
 358
 359 static int ext4_valid_extent_idx(struct inode *inode,
 360                                 struct ext4_extent_idx *ext_idx)
 361 {
 362         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 363
 364         return ext4_inode_block_valid(inode, block, 1);
 365 }
 366
 367 static int ext4_valid_extent_entries(struct inode *inode,
 368                                      struct ext4_extent_header *eh,
 369                                      ext4_lblk_t lblk, ext4_fsblk_t *pblk,
 370                                      int depth)
 371 {
 372         unsigned short entries;
 373         ext4_lblk_t lblock = 0;
 374         ext4_lblk_t cur = 0;
 375
 376         if (eh->eh_entries == 0)
 377                 return 1;
 378
 379         entries = le16_to_cpu(eh->eh_entries);
 380
 381         if (depth == 0) {
 382                 /* leaf entries */
 383                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 384
 385                 /*
 386                  * The logical block in the first entry should equal to
 387                  * the number in the index block.
 388                  */
 389                 if (depth != ext_depth(inode) &&
 390                     lblk != le32_to_cpu(ext->ee_block))
 391                         return 0;
 392                 while (entries) {
 393                         if (!ext4_valid_extent(inode, ext))
 394                                 return 0;
 395
 396                         /* Check for overlapping extents */
 397                         lblock = le32_to_cpu(ext->ee_block);
 398                         if (lblock < cur) {
 399                                 *pblk = ext4_ext_pblock(ext);
 400                                 return 0;
 401                         }
 402                         cur = lblock + ext4_ext_get_actual_len(ext);
 403                         ext++;
 404                         entries--;
 405                 }
 406         } else {
 407                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 408
 409                 /*
 410                  * The logical block in the first entry should equal to
 411                  * the number in the parent index block.
 412                  */
 413                 if (depth != ext_depth(inode) &&
 414                     lblk != le32_to_cpu(ext_idx->ei_block))
 415                         return 0;
 416                 while (entries) {
 417                         if (!ext4_valid_extent_idx(inode, ext_idx))
 418                                 return 0;
 419
 420                         /* Check for overlapping index extents */
 421                         lblock = le32_to_cpu(ext_idx->ei_block);
 422                         if (lblock < cur) {
 423                                 *pblk = ext4_idx_pblock(ext_idx);
 424                                 return 0;
 425                         }
 426                         ext_idx++;
 427                         entries--;
 428                         cur = lblock + 1;
 429                 }
 430         }
 431         return 1;
 432 }
 433
 434 static int __ext4_ext_check(const char *function, unsigned int line,
 435                             struct inode *inode, struct ext4_extent_header *eh,
 436                             int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk)
 437 {
 438         const char *error_msg;
 439         int max = 0, err = -EFSCORRUPTED;
 440
 441         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 442                 error_msg = "invalid magic";
 443                 goto corrupted;
 444         }
 445         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 446                 error_msg = "unexpected eh_depth";
 447                 goto corrupted;
 448         }
 449         if (unlikely(eh->eh_max == 0)) {
 450                 error_msg = "invalid eh_max";
 451                 goto corrupted;
 452         }
 453         max = ext4_ext_max_entries(inode, depth);
 454         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 455                 error_msg = "too large eh_max";
 456                 goto corrupted;
 457         }
 458         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 459                 error_msg = "invalid eh_entries";
 460                 goto corrupted;
 461         }
 462         if (unlikely((eh->eh_entries == 0) && (depth > 0))) {
 463                 error_msg = "eh_entries is 0 but eh_depth is > 0";
 464                 goto corrupted;
 465         }
 466         if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) {
 467                 error_msg = "invalid extent entries";
 468                 goto corrupted;
 469         }
 470         if (unlikely(depth > 32)) {
 471                 error_msg = "too large eh_depth";
 472                 goto corrupted;
 473         }
 474         /* Verify checksum on non-root extent tree nodes */
 475         if (ext_depth(inode) != depth &&
 476             !ext4_extent_block_csum_verify(inode, eh)) {
 477                 error_msg = "extent tree corrupted";
 478                 err = -EFSBADCRC;
 479                 goto corrupted;
 480         }
 481         return 0;
 482
 483 corrupted:
 484         ext4_error_inode_err(inode, function, line, 0, -err,
 485                              "pblk %llu bad header/extent: %s - magic %x, "
 486                              "entries %u, max %u(%u), depth %u(%u)",
 487                              (unsigned long long) pblk, error_msg,
 488                              le16_to_cpu(eh->eh_magic),
 489                              le16_to_cpu(eh->eh_entries),
 490                              le16_to_cpu(eh->eh_max),
 491                              max, le16_to_cpu(eh->eh_depth), depth);
 492         return err;
 493 }
 494
 495 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 496         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)
 497
 498 int ext4_ext_check_inode(struct inode *inode)
 499 {
 500         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 501 }
 502
 503 static void ext4_cache_extents(struct inode *inode,
 504                                struct ext4_extent_header *eh)
 505 {
 506         struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 507         ext4_lblk_t prev = 0;
 508         int i;
 509
 510         for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 511                 unsigned int status = EXTENT_STATUS_WRITTEN;
 512                 ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 513                 int len = ext4_ext_get_actual_len(ex);
 514
 515                 if (prev && (prev != lblk))
 516                         ext4_es_cache_extent(inode, prev, lblk - prev, ~0,
 517                                              EXTENT_STATUS_HOLE);
 518
 519                 if (ext4_ext_is_unwritten(ex))
 520                         status = EXTENT_STATUS_UNWRITTEN;
 521                 ext4_es_cache_extent(inode, lblk, len,
 522                                      ext4_ext_pblock(ex), status);
 523                 prev = lblk + len;
 524         }
 525 }
 526
 527 static struct buffer_head *
 528 __read_extent_tree_block(const char *function, unsigned int line,
 529                          struct inode *inode, struct ext4_extent_idx *idx,
 530                          int depth, int flags)
 531 {
 532         struct buffer_head              *bh;
 533         int                             err;
 534         gfp_t                           gfp_flags = __GFP_MOVABLE | GFP_NOFS;
 535         ext4_fsblk_t                    pblk;
 536
 537         if (flags & EXT4_EX_NOFAIL)
 538                 gfp_flags |= __GFP_NOFAIL;
 539
 540         pblk = ext4_idx_pblock(idx);
 541         bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);
 542         if (unlikely(!bh))
 543                 return ERR_PTR(-ENOMEM);
 544
 545         if (!bh_uptodate_or_lock(bh)) {
 546                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 547                 err = ext4_read_bh(bh, 0, NULL);
 548                 if (err < 0)
 549                         goto errout;
 550         }
 551         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 552                 return bh;
 553         err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh),
 554                                depth, pblk, le32_to_cpu(idx->ei_block));
 555         if (err)
 556                 goto errout;
 557         set_buffer_verified(bh);
 558         /*
 559          * If this is a leaf block, cache all of its entries
 560          */
 561         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 562                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 563                 ext4_cache_extents(inode, eh);
 564         }
 565         return bh;
 566 errout:
 567         put_bh(bh);
 568         return ERR_PTR(err);
 569
 570 }
 571
 572 #define read_extent_tree_block(inode, idx, depth, flags)                \
 573         __read_extent_tree_block(__func__, __LINE__, (inode), (idx),    \
 574                                  (depth), (flags))
 575
 576 /*
 577  * This function is called to cache a file's extent information in the
 578  * extent status tree
 579  */
 580 int ext4_ext_precache(struct inode *inode)
 581 {
 582         struct ext4_inode_info *ei = EXT4_I(inode);
 583         struct ext4_ext_path *path = NULL;
 584         struct buffer_head *bh;
 585         int i = 0, depth, ret = 0;
 586
 587         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 588                 return 0;       /* not an extent-mapped inode */
 589
 590         down_read(&ei->i_data_sem);
 591         depth = ext_depth(inode);
 592
 593         /* Don't cache anything if there are no external extent blocks */
 594         if (!depth) {
 595                 up_read(&ei->i_data_sem);
 596                 return ret;
 597         }
 598
 599         path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
 600                        GFP_NOFS);
 601         if (path == NULL) {
 602                 up_read(&ei->i_data_sem);
 603                 return -ENOMEM;
 604         }
 605
 606         path[0].p_hdr = ext_inode_hdr(inode);
 607         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 608         if (ret)
 609                 goto out;
 610         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 611         while (i >= 0) {
 612                 /*
 613                  * If this is a leaf block or we've reached the end of
 614                  * the index block, go up
 615                  */
 616                 if ((i == depth) ||
 617                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 618                         brelse(path[i].p_bh);
 619                         path[i].p_bh = NULL;
 620                         i--;
 621                         continue;
 622                 }
 623                 bh = read_extent_tree_block(inode, path[i].p_idx++,
 624                                             depth - i - 1,
 625                                             EXT4_EX_FORCE_CACHE);
 626                 if (IS_ERR(bh)) {
 627                         ret = PTR_ERR(bh);
 628                         break;
 629                 }
 630                 i++;
 631                 path[i].p_bh = bh;
 632                 path[i].p_hdr = ext_block_hdr(bh);
 633                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 634         }
 635         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 636 out:
 637         up_read(&ei->i_data_sem);
 638         ext4_ext_drop_refs(path);
 639         kfree(path);
 640         return ret;
 641 }
 642
 643 #ifdef EXT_DEBUG
 644 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 645 {
 646         int k, l = path->p_depth;
 647
 648         ext_debug(inode, "path:");
 649         for (k = 0; k <= l; k++, path++) {
 650                 if (path->p_idx) {
 651                         ext_debug(inode, "  %d->%llu",
 652                                   le32_to_cpu(path->p_idx->ei_block),
 653                                   ext4_idx_pblock(path->p_idx));
 654                 } else if (path->p_ext) {
 655                         ext_debug(inode, "  %d:[%d]%d:%llu ",
 656                                   le32_to_cpu(path->p_ext->ee_block),
 657                                   ext4_ext_is_unwritten(path->p_ext),
 658                                   ext4_ext_get_actual_len(path->p_ext),
 659                                   ext4_ext_pblock(path->p_ext));
 660                 } else
 661                         ext_debug(inode, "  []");
 662         }
 663         ext_debug(inode, "\n");
 664 }
 665
 666 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 667 {
 668         int depth = ext_depth(inode);
 669         struct ext4_extent_header *eh;
 670         struct ext4_extent *ex;
 671         int i;
 672
 673         if (!path)
 674                 return;
 675
 676         eh = path[depth].p_hdr;
 677         ex = EXT_FIRST_EXTENT(eh);
 678
 679         ext_debug(inode, "Displaying leaf extents\n");
 680
 681         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 682                 ext_debug(inode, "%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 683                           ext4_ext_is_unwritten(ex),
 684                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 685         }
 686         ext_debug(inode, "\n");
 687 }
 688
 689 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 690                         ext4_fsblk_t newblock, int level)
 691 {
 692         int depth = ext_depth(inode);
 693         struct ext4_extent *ex;
 694
 695         if (depth != level) {
 696                 struct ext4_extent_idx *idx;
 697                 idx = path[level].p_idx;
 698                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 699                         ext_debug(inode, "%d: move %d:%llu in new index %llu\n",
 700                                   level, le32_to_cpu(idx->ei_block),
 701                                   ext4_idx_pblock(idx), newblock);
 702                         idx++;
 703                 }
 704
 705                 return;
 706         }
 707
 708         ex = path[depth].p_ext;
 709         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 710                 ext_debug(inode, "move %d:%llu:[%d]%d in new leaf %llu\n",
 711                                 le32_to_cpu(ex->ee_block),
 712                                 ext4_ext_pblock(ex),
 713                                 ext4_ext_is_unwritten(ex),
 714                                 ext4_ext_get_actual_len(ex),
 715                                 newblock);
 716                 ex++;
 717         }
 718 }
 719
 720 #else
 721 #define ext4_ext_show_path(inode, path)
 722 #define ext4_ext_show_leaf(inode, path)
 723 #define ext4_ext_show_move(inode, path, newblock, level)
 724 #endif
 725
 726 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 727 {
 728         int depth, i;
 729
 730         if (!path)
 731                 return;
 732         depth = path->p_depth;
 733         for (i = 0; i <= depth; i++, path++) {
 734                 brelse(path->p_bh);
 735                 path->p_bh = NULL;
 736         }
 737 }
 738
 739 /*
 740  * ext4_ext_binsearch_idx:
 741  * binary search for the closest index of the given block
 742  * the header must be checked before calling this
 743  */
 744 static void
 745 ext4_ext_binsearch_idx(struct inode *inode,
 746                         struct ext4_ext_path *path, ext4_lblk_t block)
 747 {
 748         struct ext4_extent_header *eh = path->p_hdr;
 749         struct ext4_extent_idx *r, *l, *m;
 750
 751
 752         ext_debug(inode, "binsearch for %u(idx):  ", block);
 753
 754         l = EXT_FIRST_INDEX(eh) + 1;
 755         r = EXT_LAST_INDEX(eh);
 756         while (l <= r) {
 757                 m = l + (r - l) / 2;
 758                 if (block < le32_to_cpu(m->ei_block))
 759                         r = m - 1;
 760                 else
 761                         l = m + 1;
 762                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 763                           le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block),
 764                           r, le32_to_cpu(r->ei_block));
 765         }
 766
 767         path->p_idx = l - 1;
 768         ext_debug(inode, "  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 769                   ext4_idx_pblock(path->p_idx));
 770
 771 #ifdef CHECK_BINSEARCH
 772         {
 773                 struct ext4_extent_idx *chix, *ix;
 774                 int k;
 775
 776                 chix = ix = EXT_FIRST_INDEX(eh);
 777                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 778                         if (k != 0 && le32_to_cpu(ix->ei_block) <=
 779                             le32_to_cpu(ix[-1].ei_block)) {
 780                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 781                                        "first=0x%p\n", k,
 782                                        ix, EXT_FIRST_INDEX(eh));
 783                                 printk(KERN_DEBUG "%u <= %u\n",
 784                                        le32_to_cpu(ix->ei_block),
 785                                        le32_to_cpu(ix[-1].ei_block));
 786                         }
 787                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 788                                            <= le32_to_cpu(ix[-1].ei_block));
 789                         if (block < le32_to_cpu(ix->ei_block))
 790                                 break;
 791                         chix = ix;
 792                 }
 793                 BUG_ON(chix != path->p_idx);
 794         }
 795 #endif
 796
 797 }
 798
 799 /*
 800  * ext4_ext_binsearch:
 801  * binary search for closest extent of the given block
 802  * the header must be checked before calling this
 803  */
 804 static void
 805 ext4_ext_binsearch(struct inode *inode,
 806                 struct ext4_ext_path *path, ext4_lblk_t block)
 807 {
 808         struct ext4_extent_header *eh = path->p_hdr;
 809         struct ext4_extent *r, *l, *m;
 810
 811         if (eh->eh_entries == 0) {
 812                 /*
 813                  * this leaf is empty:
 814                  * we get such a leaf in split/add case
 815                  */
 816                 return;
 817         }
 818
 819         ext_debug(inode, "binsearch for %u:  ", block);
 820
 821         l = EXT_FIRST_EXTENT(eh) + 1;
 822         r = EXT_LAST_EXTENT(eh);
 823
 824         while (l <= r) {
 825                 m = l + (r - l) / 2;
 826                 if (block < le32_to_cpu(m->ee_block))
 827                         r = m - 1;
 828                 else
 829                         l = m + 1;
 830                 ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 831                           le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block),
 832                           r, le32_to_cpu(r->ee_block));
 833         }
 834
 835         path->p_ext = l - 1;
 836         ext_debug(inode, "  -> %d:%llu:[%d]%d ",
 837                         le32_to_cpu(path->p_ext->ee_block),
 838                         ext4_ext_pblock(path->p_ext),
 839                         ext4_ext_is_unwritten(path->p_ext),
 840                         ext4_ext_get_actual_len(path->p_ext));
 841
 842 #ifdef CHECK_BINSEARCH
 843         {
 844                 struct ext4_extent *chex, *ex;
 845                 int k;
 846
 847                 chex = ex = EXT_FIRST_EXTENT(eh);
 848                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 849                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 850                                           <= le32_to_cpu(ex[-1].ee_block));
 851                         if (block < le32_to_cpu(ex->ee_block))
 852                                 break;
 853                         chex = ex;
 854                 }
 855                 BUG_ON(chex != path->p_ext);
 856         }
 857 #endif
 858
 859 }
 860
 861 void ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 862 {
 863         struct ext4_extent_header *eh;
 864
 865         eh = ext_inode_hdr(inode);
 866         eh->eh_depth = 0;
 867         eh->eh_entries = 0;
 868         eh->eh_magic = EXT4_EXT_MAGIC;
 869         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 870         eh->eh_generation = 0;
 871         ext4_mark_inode_dirty(handle, inode);
 872 }
 873
 874 struct ext4_ext_path *
 875 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 876                  struct ext4_ext_path **orig_path, int flags)
 877 {
 878         struct ext4_extent_header *eh;
 879         struct buffer_head *bh;
 880         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 881         short int depth, i, ppos = 0;
 882         int ret;
 883         gfp_t gfp_flags = GFP_NOFS;
 884
 885         if (flags & EXT4_EX_NOFAIL)
 886                 gfp_flags |= __GFP_NOFAIL;
 887
 888         eh = ext_inode_hdr(inode);
 889         depth = ext_depth(inode);
 890         if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
 891                 EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
 892                                  depth);
 893                 ret = -EFSCORRUPTED;
 894                 goto err;
 895         }
 896
 897         if (path) {
 898                 ext4_ext_drop_refs(path);
 899                 if (depth > path[0].p_maxdepth) {
 900                         kfree(path);
 901                         *orig_path = path = NULL;
 902                 }
 903         }
 904         if (!path) {
 905                 /* account possible depth increase */
 906                 path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
 907                                 gfp_flags);
 908                 if (unlikely(!path))
 909                         return ERR_PTR(-ENOMEM);
 910                 path[0].p_maxdepth = depth + 1;
 911         }
 912         path[0].p_hdr = eh;
 913         path[0].p_bh = NULL;
 914
 915         i = depth;
 916         if (!(flags & EXT4_EX_NOCACHE) && depth == 0)
 917                 ext4_cache_extents(inode, eh);
 918         /* walk through the tree */
 919         while (i) {
 920                 ext_debug(inode, "depth %d: num %d, max %d\n",
 921                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 922
 923                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 924                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 925                 path[ppos].p_depth = i;
 926                 path[ppos].p_ext = NULL;
 927
 928                 bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);
 929                 if (IS_ERR(bh)) {
 930                         ret = PTR_ERR(bh);
 931                         goto err;
 932                 }
 933
 934                 eh = ext_block_hdr(bh);
 935                 ppos++;
 936                 path[ppos].p_bh = bh;
 937                 path[ppos].p_hdr = eh;
 938         }
 939
 940         path[ppos].p_depth = i;
 941         path[ppos].p_ext = NULL;
 942         path[ppos].p_idx = NULL;
 943
 944         /* find extent */
 945         ext4_ext_binsearch(inode, path + ppos, block);
 946         /* if not an empty leaf */
 947         if (path[ppos].p_ext)
 948                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 949
 950         ext4_ext_show_path(inode, path);
 951
 952         return path;
 953
 954 err:
 955         ext4_ext_drop_refs(path);
 956         kfree(path);
 957         if (orig_path)
 958                 *orig_path = NULL;
 959         return ERR_PTR(ret);
 960 }
 961
 962 /*
 963  * ext4_ext_insert_index:
 964  * insert new index [@logical;@ptr] into the block at @curp;
 965  * check where to insert: before @curp or after @curp
 966  */
 967 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 968                                  struct ext4_ext_path *curp,
 969                                  int logical, ext4_fsblk_t ptr)
 970 {
 971         struct ext4_extent_idx *ix;
 972         int len, err;
 973
 974         err = ext4_ext_get_access(handle, inode, curp);
 975         if (err)
 976                 return err;
 977
 978         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 979                 EXT4_ERROR_INODE(inode,
 980                                  "logical %d == ei_block %d!",
 981                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 982                 return -EFSCORRUPTED;
 983         }
 984
 985         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 986                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 987                 EXT4_ERROR_INODE(inode,
 988                                  "eh_entries %d >= eh_max %d!",
 989                                  le16_to_cpu(curp->p_hdr->eh_entries),
 990                                  le16_to_cpu(curp->p_hdr->eh_max));
 991                 return -EFSCORRUPTED;
 992         }
 993
 994         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 995                 /* insert after */
 996                 ext_debug(inode, "insert new index %d after: %llu\n",
 997                           logical, ptr);
 998                 ix = curp->p_idx + 1;
 999         } else {
1000                 /* insert before */
1001                 ext_debug(inode, "insert new index %d before: %llu\n",
1002                           logical, ptr);
1003                 ix = curp->p_idx;
1004         }
1005
1006         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
1007                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1008                 return -EFSCORRUPTED;
1009         }
1010
1011         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
1012         BUG_ON(len < 0);
1013         if (len > 0) {
1014                 ext_debug(inode, "insert new index %d: "
1015                                 "move %d indices from 0x%p to 0x%p\n",
1016                                 logical, len, ix, ix + 1);
1017                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
1018         }
1019
1020         ix->ei_block = cpu_to_le32(logical);
1021         ext4_idx_store_pblock(ix, ptr);
1022         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1023
1024         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1025                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1026                 return -EFSCORRUPTED;
1027         }
1028
1029         err = ext4_ext_dirty(handle, inode, curp);
1030         ext4_std_error(inode->i_sb, err);
1031
1032         return err;
1033 }
1034
1035 /*
1036  * ext4_ext_split:
1037  * inserts new subtree into the path, using free index entry
1038  * at depth @at:
1039  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1040  * - makes decision where to split
1041  * - moves remaining extents and index entries (right to the split point)
1042  *   into the newly allocated blocks
1043  * - initializes subtree
1044  */
1045 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1046                           unsigned int flags,
1047                           struct ext4_ext_path *path,
1048                           struct ext4_extent *newext, int at)
1049 {
1050         struct buffer_head *bh = NULL;
1051         int depth = ext_depth(inode);
1052         struct ext4_extent_header *neh;
1053         struct ext4_extent_idx *fidx;
1054         int i = at, k, m, a;
1055         ext4_fsblk_t newblock, oldblock;
1056         __le32 border;
1057         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1058         gfp_t gfp_flags = GFP_NOFS;
1059         int err = 0;
1060         size_t ext_size = 0;
1061
1062         if (flags & EXT4_EX_NOFAIL)
1063                 gfp_flags |= __GFP_NOFAIL;
1064
1065         /* make decision: where to split? */
1066         /* FIXME: now decision is simplest: at current extent */
1067
1068         /* if current leaf will be split, then we should use
1069          * border from split point */
1070         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1071                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1072                 return -EFSCORRUPTED;
1073         }
1074         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1075                 border = path[depth].p_ext[1].ee_block;
1076                 ext_debug(inode, "leaf will be split."
1077                                 " next leaf starts at %d\n",
1078                                   le32_to_cpu(border));
1079         } else {
1080                 border = newext->ee_block;
1081                 ext_debug(inode, "leaf will be added."
1082                                 " next leaf starts at %d\n",
1083                                 le32_to_cpu(border));
1084         }
1085
1086         /*
1087          * If error occurs, then we break processing
1088          * and mark filesystem read-only. index won't
1089          * be inserted and tree will be in consistent
1090          * state. Next mount will repair buffers too.
1091          */
1092
1093         /*
1094          * Get array to track all allocated blocks.
1095          * We need this to handle errors and free blocks
1096          * upon them.
1097          */
1098         ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), gfp_flags);
1099         if (!ablocks)
1100                 return -ENOMEM;
1101
1102         /* allocate all needed blocks */
1103         ext_debug(inode, "allocate %d blocks for indexes/leaf\n", depth - at);
1104         for (a = 0; a < depth - at; a++) {
1105                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1106                                                    newext, &err, flags);
1107                 if (newblock == 0)
1108                         goto cleanup;
1109                 ablocks[a] = newblock;
1110         }
1111
1112         /* initialize new leaf */
1113         newblock = ablocks[--a];
1114         if (unlikely(newblock == 0)) {
1115                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1116                 err = -EFSCORRUPTED;
1117                 goto cleanup;
1118         }
1119         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1120         if (unlikely(!bh)) {
1121                 err = -ENOMEM;
1122                 goto cleanup;
1123         }
1124         lock_buffer(bh);
1125
1126         err = ext4_journal_get_create_access(handle, bh);
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, bh);
1205                 if (err)
1206                         goto cleanup;
1207
1208                 neh = ext_block_hdr(bh);
1209                 neh->eh_entries = cpu_to_le16(1);
1210                 neh->eh_magic = EXT4_EXT_MAGIC;
1211                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1212                 neh->eh_depth = cpu_to_le16(depth - i);
1213                 neh->eh_generation = 0;
1214                 fidx = EXT_FIRST_INDEX(neh);
1215                 fidx->ei_block = border;
1216                 ext4_idx_store_pblock(fidx, oldblock);
1217
1218                 ext_debug(inode, "int.index at %d (block %llu): %u -> %llu\n",
1219                                 i, newblock, le32_to_cpu(border), oldblock);
1220
1221                 /* move remainder of path[i] to the new index block */
1222                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1223                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1224                         EXT4_ERROR_INODE(inode,
1225                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1226                                          le32_to_cpu(path[i].p_ext->ee_block));
1227                         err = -EFSCORRUPTED;
1228                         goto cleanup;
1229                 }
1230                 /* start copy indexes */
1231                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1232                 ext_debug(inode, "cur 0x%p, last 0x%p\n", path[i].p_idx,
1233                                 EXT_MAX_INDEX(path[i].p_hdr));
1234                 ext4_ext_show_move(inode, path, newblock, i);
1235                 if (m) {
1236                         memmove(++fidx, path[i].p_idx,
1237                                 sizeof(struct ext4_extent_idx) * m);
1238                         le16_add_cpu(&neh->eh_entries, m);
1239                 }
1240                 /* zero out unused area in the extent block */
1241                 ext_size = sizeof(struct ext4_extent_header) +
1242                    (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));
1243                 memset(bh->b_data + ext_size, 0,
1244                         inode->i_sb->s_blocksize - ext_size);
1245                 ext4_extent_block_csum_set(inode, neh);
1246                 set_buffer_uptodate(bh);
1247                 unlock_buffer(bh);
1248
1249                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1250                 if (err)
1251                         goto cleanup;
1252                 brelse(bh);
1253                 bh = NULL;
1254
1255                 /* correct old index */
1256                 if (m) {
1257                         err = ext4_ext_get_access(handle, inode, path + i);
1258                         if (err)
1259                                 goto cleanup;
1260                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1261                         err = ext4_ext_dirty(handle, inode, path + i);
1262                         if (err)
1263                                 goto cleanup;
1264                 }
1265
1266                 i--;
1267         }
1268
1269         /* insert new index */
1270         err = ext4_ext_insert_index(handle, inode, path + at,
1271                                     le32_to_cpu(border), newblock);
1272
1273 cleanup:
1274         if (bh) {
1275                 if (buffer_locked(bh))
1276                         unlock_buffer(bh);
1277                 brelse(bh);
1278         }
1279
1280         if (err) {
1281                 /* free all allocated blocks in error case */
1282                 for (i = 0; i < depth; i++) {
1283                         if (!ablocks[i])
1284                                 continue;
1285                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1286                                          EXT4_FREE_BLOCKS_METADATA);
1287                 }
1288         }
1289         kfree(ablocks);
1290
1291         return err;
1292 }
1293
1294 /*
1295  * ext4_ext_grow_indepth:
1296  * implements tree growing procedure:
1297  * - allocates new block
1298  * - moves top-level data (index block or leaf) into the new block
1299  * - initializes new top-level, creating index that points to the
1300  *   just created block
1301  */
1302 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1303                                  unsigned int flags)
1304 {
1305         struct ext4_extent_header *neh;
1306         struct buffer_head *bh;
1307         ext4_fsblk_t newblock, goal = 0;
1308         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1309         int err = 0;
1310         size_t ext_size = 0;
1311
1312         /* Try to prepend new index to old one */
1313         if (ext_depth(inode))
1314                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1315         if (goal > le32_to_cpu(es->s_first_data_block)) {
1316                 flags |= EXT4_MB_HINT_TRY_GOAL;
1317                 goal--;
1318         } else
1319                 goal = ext4_inode_to_goal_block(inode);
1320         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1321                                         NULL, &err);
1322         if (newblock == 0)
1323                 return err;
1324
1325         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1326         if (unlikely(!bh))
1327                 return -ENOMEM;
1328         lock_buffer(bh);
1329
1330         err = ext4_journal_get_create_access(handle, bh);
1331         if (err) {
1332                 unlock_buffer(bh);
1333                 goto out;
1334         }
1335
1336         ext_size = sizeof(EXT4_I(inode)->i_data);
1337         /* move top-level index/leaf into new block */
1338         memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);
1339         /* zero out unused area in the extent block */
1340         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1341
1342         /* set size of new block */
1343         neh = ext_block_hdr(bh);
1344         /* old root could have indexes or leaves
1345          * so calculate e_max right way */
1346         if (ext_depth(inode))
1347                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1348         else
1349                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1350         neh->eh_magic = EXT4_EXT_MAGIC;
1351         ext4_extent_block_csum_set(inode, neh);
1352         set_buffer_uptodate(bh);
1353         unlock_buffer(bh);
1354
1355         err = ext4_handle_dirty_metadata(handle, inode, bh);
1356         if (err)
1357                 goto out;
1358
1359         /* Update top-level index: num,max,pointer */
1360         neh = ext_inode_hdr(inode);
1361         neh->eh_entries = cpu_to_le16(1);
1362         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1363         if (neh->eh_depth == 0) {
1364                 /* Root extent block becomes index block */
1365                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1366                 EXT_FIRST_INDEX(neh)->ei_block =
1367                         EXT_FIRST_EXTENT(neh)->ee_block;
1368         }
1369         ext_debug(inode, "new root: num %d(%d), lblock %d, ptr %llu\n",
1370                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1371                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1372                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1373
1374         le16_add_cpu(&neh->eh_depth, 1);
1375         err = ext4_mark_inode_dirty(handle, inode);
1376 out:
1377         brelse(bh);
1378
1379         return err;
1380 }
1381
1382 /*
1383  * ext4_ext_create_new_leaf:
1384  * finds empty index and adds new leaf.
1385  * if no free index is found, then it requests in-depth growing.
1386  */
1387 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1388                                     unsigned int mb_flags,
1389                                     unsigned int gb_flags,
1390                                     struct ext4_ext_path **ppath,
1391                                     struct ext4_extent *newext)
1392 {
1393         struct ext4_ext_path *path = *ppath;
1394         struct ext4_ext_path *curp;
1395         int depth, i, err = 0;
1396
1397 repeat:
1398         i = depth = ext_depth(inode);
1399
1400         /* walk up to the tree and look for free index entry */
1401         curp = path + depth;
1402         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1403                 i--;
1404                 curp--;
1405         }
1406
1407         /* we use already allocated block for index block,
1408          * so subsequent data blocks should be contiguous */
1409         if (EXT_HAS_FREE_INDEX(curp)) {
1410                 /* if we found index with free entry, then use that
1411                  * entry: create all needed subtree and add new leaf */
1412                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1413                 if (err)
1414                         goto out;
1415
1416                 /* refill path */
1417                 path = ext4_find_extent(inode,
1418                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1419                                     ppath, gb_flags);
1420                 if (IS_ERR(path))
1421                         err = PTR_ERR(path);
1422         } else {
1423                 /* tree is full, time to grow in depth */
1424                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1425                 if (err)
1426                         goto out;
1427
1428                 /* refill path */
1429                 path = ext4_find_extent(inode,
1430                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1431                                     ppath, gb_flags);
1432                 if (IS_ERR(path)) {
1433                         err = PTR_ERR(path);
1434                         goto out;
1435                 }
1436
1437                 /*
1438                  * only first (depth 0 -> 1) produces free space;
1439                  * in all other cases we have to split the grown tree
1440                  */
1441                 depth = ext_depth(inode);
1442                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1443                         /* now we need to split */
1444                         goto repeat;
1445                 }
1446         }
1447
1448 out:
1449         return err;
1450 }
1451
1452 /*
1453  * search the closest allocated block to the left for *logical
1454  * and returns it at @logical + it's physical address at @phys
1455  * if *logical is the smallest allocated block, the function
1456  * returns 0 at @phys
1457  * return value contains 0 (success) or error code
1458  */
1459 static int ext4_ext_search_left(struct inode *inode,
1460                                 struct ext4_ext_path *path,
1461                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1462 {
1463         struct ext4_extent_idx *ix;
1464         struct ext4_extent *ex;
1465         int depth, ee_len;
1466
1467         if (unlikely(path == NULL)) {
1468                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1469                 return -EFSCORRUPTED;
1470         }
1471         depth = path->p_depth;
1472         *phys = 0;
1473
1474         if (depth == 0 && path->p_ext == NULL)
1475                 return 0;
1476
1477         /* usually extent in the path covers blocks smaller
1478          * then *logical, but it can be that extent is the
1479          * first one in the file */
1480
1481         ex = path[depth].p_ext;
1482         ee_len = ext4_ext_get_actual_len(ex);
1483         if (*logical < le32_to_cpu(ex->ee_block)) {
1484                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1485                         EXT4_ERROR_INODE(inode,
1486                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1487                                          *logical, le32_to_cpu(ex->ee_block));
1488                         return -EFSCORRUPTED;
1489                 }
1490                 while (--depth >= 0) {
1491                         ix = path[depth].p_idx;
1492                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1493                                 EXT4_ERROR_INODE(inode,
1494                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1495                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1496                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1497                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1498                                   depth);
1499                                 return -EFSCORRUPTED;
1500                         }
1501                 }
1502                 return 0;
1503         }
1504
1505         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1506                 EXT4_ERROR_INODE(inode,
1507                                  "logical %d < ee_block %d + ee_len %d!",
1508                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1509                 return -EFSCORRUPTED;
1510         }
1511
1512         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1513         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1514         return 0;
1515 }
1516
1517 /*
1518  * Search the closest allocated block to the right for *logical
1519  * and returns it at @logical + it's physical address at @phys.
1520  * If not exists, return 0 and @phys is set to 0. We will return
1521  * 1 which means we found an allocated block and ret_ex is valid.
1522  * Or return a (< 0) error code.
1523  */
1524 static int ext4_ext_search_right(struct inode *inode,
1525                                  struct ext4_ext_path *path,
1526                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1527                                  struct ext4_extent *ret_ex)
1528 {
1529         struct buffer_head *bh = NULL;
1530         struct ext4_extent_header *eh;
1531         struct ext4_extent_idx *ix;
1532         struct ext4_extent *ex;
1533         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1534         int ee_len;
1535
1536         if (unlikely(path == NULL)) {
1537                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1538                 return -EFSCORRUPTED;
1539         }
1540         depth = path->p_depth;
1541         *phys = 0;
1542
1543         if (depth == 0 && path->p_ext == NULL)
1544                 return 0;
1545
1546         /* usually extent in the path covers blocks smaller
1547          * then *logical, but it can be that extent is the
1548          * first one in the file */
1549
1550         ex = path[depth].p_ext;
1551         ee_len = ext4_ext_get_actual_len(ex);
1552         if (*logical < le32_to_cpu(ex->ee_block)) {
1553                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1554                         EXT4_ERROR_INODE(inode,
1555                                          "first_extent(path[%d].p_hdr) != ex",
1556                                          depth);
1557                         return -EFSCORRUPTED;
1558                 }
1559                 while (--depth >= 0) {
1560                         ix = path[depth].p_idx;
1561                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1562                                 EXT4_ERROR_INODE(inode,
1563                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1564                                                  *logical);
1565                                 return -EFSCORRUPTED;
1566                         }
1567                 }
1568                 goto found_extent;
1569         }
1570
1571         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1572                 EXT4_ERROR_INODE(inode,
1573                                  "logical %d < ee_block %d + ee_len %d!",
1574                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1575                 return -EFSCORRUPTED;
1576         }
1577
1578         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1579                 /* next allocated block in this leaf */
1580                 ex++;
1581                 goto found_extent;
1582         }
1583
1584         /* go up and search for index to the right */
1585         while (--depth >= 0) {
1586                 ix = path[depth].p_idx;
1587                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1588                         goto got_index;
1589         }
1590
1591         /* we've gone up to the root and found no index to the right */
1592         return 0;
1593
1594 got_index:
1595         /* we've found index to the right, let's
1596          * follow it and find the closest allocated
1597          * block to the right */
1598         ix++;
1599         while (++depth < path->p_depth) {
1600                 /* subtract from p_depth to get proper eh_depth */
1601                 bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
1602                 if (IS_ERR(bh))
1603                         return PTR_ERR(bh);
1604                 eh = ext_block_hdr(bh);
1605                 ix = EXT_FIRST_INDEX(eh);
1606                 put_bh(bh);
1607         }
1608
1609         bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
1610         if (IS_ERR(bh))
1611                 return PTR_ERR(bh);
1612         eh = ext_block_hdr(bh);
1613         ex = EXT_FIRST_EXTENT(eh);
1614 found_extent:
1615         *logical = le32_to_cpu(ex->ee_block);
1616         *phys = ext4_ext_pblock(ex);
1617         if (ret_ex)
1618                 *ret_ex = *ex;
1619         if (bh)
1620                 put_bh(bh);
1621         return 1;
1622 }
1623
1624 /*
1625  * ext4_ext_next_allocated_block:
1626  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1627  * NOTE: it considers block number from index entry as
1628  * allocated block. Thus, index entries have to be consistent
1629  * with leaves.
1630  */
1631 ext4_lblk_t
1632 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1633 {
1634         int depth;
1635
1636         BUG_ON(path == NULL);
1637         depth = path->p_depth;
1638
1639         if (depth == 0 && path->p_ext == NULL)
1640                 return EXT_MAX_BLOCKS;
1641
1642         while (depth >= 0) {
1643                 struct ext4_ext_path *p = &path[depth];
1644
1645                 if (depth == path->p_depth) {
1646                         /* leaf */
1647                         if (p->p_ext && p->p_ext != EXT_LAST_EXTENT(p->p_hdr))
1648                                 return le32_to_cpu(p->p_ext[1].ee_block);
1649                 } else {
1650                         /* index */
1651                         if (p->p_idx != EXT_LAST_INDEX(p->p_hdr))
1652                                 return le32_to_cpu(p->p_idx[1].ei_block);
1653                 }
1654                 depth--;
1655         }
1656
1657         return EXT_MAX_BLOCKS;
1658 }
1659
1660 /*
1661  * ext4_ext_next_leaf_block:
1662  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1663  */
1664 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1665 {
1666         int depth;
1667
1668         BUG_ON(path == NULL);
1669         depth = path->p_depth;
1670
1671         /* zero-tree has no leaf blocks at all */
1672         if (depth == 0)
1673                 return EXT_MAX_BLOCKS;
1674
1675         /* go to index block */
1676         depth--;
1677
1678         while (depth >= 0) {
1679                 if (path[depth].p_idx !=
1680                                 EXT_LAST_INDEX(path[depth].p_hdr))
1681                         return (ext4_lblk_t)
1682                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1683                 depth--;
1684         }
1685
1686         return EXT_MAX_BLOCKS;
1687 }
1688
1689 /*
1690  * ext4_ext_correct_indexes:
1691  * if leaf gets modified and modified extent is first in the leaf,
1692  * then we have to correct all indexes above.
1693  * TODO: do we need to correct tree in all cases?
1694  */
1695 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1696                                 struct ext4_ext_path *path)
1697 {
1698         struct ext4_extent_header *eh;
1699         int depth = ext_depth(inode);
1700         struct ext4_extent *ex;
1701         __le32 border;
1702         int k, err = 0;
1703
1704         eh = path[depth].p_hdr;
1705         ex = path[depth].p_ext;
1706
1707         if (unlikely(ex == NULL || eh == NULL)) {
1708                 EXT4_ERROR_INODE(inode,
1709                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1710                 return -EFSCORRUPTED;
1711         }
1712
1713         if (depth == 0) {
1714                 /* there is no tree at all */
1715                 return 0;
1716         }
1717
1718         if (ex != EXT_FIRST_EXTENT(eh)) {
1719                 /* we correct tree if first leaf got modified only */
1720                 return 0;
1721         }
1722
1723         /*
1724          * TODO: we need correction if border is smaller than current one
1725          */
1726         k = depth - 1;
1727         border = path[depth].p_ext->ee_block;
1728         err = ext4_ext_get_access(handle, inode, path + k);
1729         if (err)
1730                 return err;
1731         path[k].p_idx->ei_block = border;
1732         err = ext4_ext_dirty(handle, inode, path + k);
1733         if (err)
1734                 return err;
1735
1736         while (k--) {
1737                 /* change all left-side indexes */
1738                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1739                         break;
1740                 err = ext4_ext_get_access(handle, inode, path + k);
1741                 if (err)
1742                         break;
1743                 path[k].p_idx->ei_block = border;
1744                 err = ext4_ext_dirty(handle, inode, path + k);
1745                 if (err)
1746                         break;
1747         }
1748
1749         return err;
1750 }
1751
1752 static int ext4_can_extents_be_merged(struct inode *inode,
1753                                       struct ext4_extent *ex1,
1754                                       struct ext4_extent *ex2)
1755 {
1756         unsigned short ext1_ee_len, ext2_ee_len;
1757
1758         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1759                 return 0;
1760
1761         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1762         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1763
1764         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1765                         le32_to_cpu(ex2->ee_block))
1766                 return 0;
1767
1768         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1769                 return 0;
1770
1771         if (ext4_ext_is_unwritten(ex1) &&
1772             ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)
1773                 return 0;
1774 #ifdef AGGRESSIVE_TEST
1775         if (ext1_ee_len >= 4)
1776                 return 0;
1777 #endif
1778
1779         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1780                 return 1;
1781         return 0;
1782 }
1783
1784 /*
1785  * This function tries to merge the "ex" extent to the next extent in the tree.
1786  * It always tries to merge towards right. If you want to merge towards
1787  * left, pass "ex - 1" as argument instead of "ex".
1788  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1789  * 1 if they got merged.
1790  */
1791 static int ext4_ext_try_to_merge_right(struct inode *inode,
1792                                  struct ext4_ext_path *path,
1793                                  struct ext4_extent *ex)
1794 {
1795         struct ext4_extent_header *eh;
1796         unsigned int depth, len;
1797         int merge_done = 0, unwritten;
1798
1799         depth = ext_depth(inode);
1800         BUG_ON(path[depth].p_hdr == NULL);
1801         eh = path[depth].p_hdr;
1802
1803         while (ex < EXT_LAST_EXTENT(eh)) {
1804                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1805                         break;
1806                 /* merge with next extent! */
1807                 unwritten = ext4_ext_is_unwritten(ex);
1808                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1809                                 + ext4_ext_get_actual_len(ex + 1));
1810                 if (unwritten)
1811                         ext4_ext_mark_unwritten(ex);
1812
1813                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1814                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1815                                 * sizeof(struct ext4_extent);
1816                         memmove(ex + 1, ex + 2, len);
1817                 }
1818                 le16_add_cpu(&eh->eh_entries, -1);
1819                 merge_done = 1;
1820                 WARN_ON(eh->eh_entries == 0);
1821                 if (!eh->eh_entries)
1822                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1823         }
1824
1825         return merge_done;
1826 }
1827
1828 /*
1829  * This function does a very simple check to see if we can collapse
1830  * an extent tree with a single extent tree leaf block into the inode.
1831  */
1832 static void ext4_ext_try_to_merge_up(handle_t *handle,
1833                                      struct inode *inode,
1834                                      struct ext4_ext_path *path)
1835 {
1836         size_t s;
1837         unsigned max_root = ext4_ext_space_root(inode, 0);
1838         ext4_fsblk_t blk;
1839
1840         if ((path[0].p_depth != 1) ||
1841             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1842             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1843                 return;
1844
1845         /*
1846          * We need to modify the block allocation bitmap and the block
1847          * group descriptor to release the extent tree block.  If we
1848          * can't get the journal credits, give up.
1849          */
1850         if (ext4_journal_extend(handle, 2,
1851                         ext4_free_metadata_revoke_credits(inode->i_sb, 1)))
1852                 return;
1853
1854         /*
1855          * Copy the extent data up to the inode
1856          */
1857         blk = ext4_idx_pblock(path[0].p_idx);
1858         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1859                 sizeof(struct ext4_extent_idx);
1860         s += sizeof(struct ext4_extent_header);
1861
1862         path[1].p_maxdepth = path[0].p_maxdepth;
1863         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1864         path[0].p_depth = 0;
1865         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1866                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1867         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1868
1869         brelse(path[1].p_bh);
1870         ext4_free_blocks(handle, inode, NULL, blk, 1,
1871                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1872 }
1873
1874 /*
1875  * This function tries to merge the @ex extent to neighbours in the tree, then
1876  * tries to collapse the extent tree into the inode.
1877  */
1878 static void ext4_ext_try_to_merge(handle_t *handle,
1879                                   struct inode *inode,
1880                                   struct ext4_ext_path *path,
1881                                   struct ext4_extent *ex)
1882 {
1883         struct ext4_extent_header *eh;
1884         unsigned int depth;
1885         int merge_done = 0;
1886
1887         depth = ext_depth(inode);
1888         BUG_ON(path[depth].p_hdr == NULL);
1889         eh = path[depth].p_hdr;
1890
1891         if (ex > EXT_FIRST_EXTENT(eh))
1892                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1893
1894         if (!merge_done)
1895                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1896
1897         ext4_ext_try_to_merge_up(handle, inode, path);
1898 }
1899
1900 /*
1901  * check if a portion of the "newext" extent overlaps with an
1902  * existing extent.
1903  *
1904  * If there is an overlap discovered, it updates the length of the newext
1905  * such that there will be no overlap, and then returns 1.
1906  * If there is no overlap found, it returns 0.
1907  */
1908 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1909                                            struct inode *inode,
1910                                            struct ext4_extent *newext,
1911                                            struct ext4_ext_path *path)
1912 {
1913         ext4_lblk_t b1, b2;
1914         unsigned int depth, len1;
1915         unsigned int ret = 0;
1916
1917         b1 = le32_to_cpu(newext->ee_block);
1918         len1 = ext4_ext_get_actual_len(newext);
1919         depth = ext_depth(inode);
1920         if (!path[depth].p_ext)
1921                 goto out;
1922         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1923
1924         /*
1925          * get the next allocated block if the extent in the path
1926          * is before the requested block(s)
1927          */
1928         if (b2 < b1) {
1929                 b2 = ext4_ext_next_allocated_block(path);
1930                 if (b2 == EXT_MAX_BLOCKS)
1931                         goto out;
1932                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1933         }
1934
1935         /* check for wrap through zero on extent logical start block*/
1936         if (b1 + len1 < b1) {
1937                 len1 = EXT_MAX_BLOCKS - b1;
1938                 newext->ee_len = cpu_to_le16(len1);
1939                 ret = 1;
1940         }
1941
1942         /* check for overlap */
1943         if (b1 + len1 > b2) {
1944                 newext->ee_len = cpu_to_le16(b2 - b1);
1945                 ret = 1;
1946         }
1947 out:
1948         return ret;
1949 }
1950
1951 /*
1952  * ext4_ext_insert_extent:
1953  * tries to merge requested extent into the existing extent or
1954  * inserts requested extent as new one into the tree,
1955  * creating new leaf in the no-space case.
1956  */
1957 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1958                                 struct ext4_ext_path **ppath,
1959                                 struct ext4_extent *newext, int gb_flags)
1960 {
1961         struct ext4_ext_path *path = *ppath;
1962         struct ext4_extent_header *eh;
1963         struct ext4_extent *ex, *fex;
1964         struct ext4_extent *nearex; /* nearest extent */
1965         struct ext4_ext_path *npath = NULL;
1966         int depth, len, err;
1967         ext4_lblk_t next;
1968         int mb_flags = 0, unwritten;
1969
1970         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1971                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1972         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1973                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1974                 return -EFSCORRUPTED;
1975         }
1976         depth = ext_depth(inode);
1977         ex = path[depth].p_ext;
1978         eh = path[depth].p_hdr;
1979         if (unlikely(path[depth].p_hdr == NULL)) {
1980                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1981                 return -EFSCORRUPTED;
1982         }
1983
1984         /* try to insert block into found extent and return */
1985         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1986
1987                 /*
1988                  * Try to see whether we should rather test the extent on
1989                  * right from ex, or from the left of ex. This is because
1990                  * ext4_find_extent() can return either extent on the
1991                  * left, or on the right from the searched position. This
1992                  * will make merging more effective.
1993                  */
1994                 if (ex < EXT_LAST_EXTENT(eh) &&
1995                     (le32_to_cpu(ex->ee_block) +
1996                     ext4_ext_get_actual_len(ex) <
1997                     le32_to_cpu(newext->ee_block))) {
1998                         ex += 1;
1999                         goto prepend;
2000                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
2001                            (le32_to_cpu(newext->ee_block) +
2002                            ext4_ext_get_actual_len(newext) <
2003                            le32_to_cpu(ex->ee_block)))
2004                         ex -= 1;
2005
2006                 /* Try to append newex to the ex */
2007                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
2008                         ext_debug(inode, "append [%d]%d block to %u:[%d]%d"
2009                                   "(from %llu)\n",
2010                                   ext4_ext_is_unwritten(newext),
2011                                   ext4_ext_get_actual_len(newext),
2012                                   le32_to_cpu(ex->ee_block),
2013                                   ext4_ext_is_unwritten(ex),
2014                                   ext4_ext_get_actual_len(ex),
2015                                   ext4_ext_pblock(ex));
2016                         err = ext4_ext_get_access(handle, inode,
2017                                                   path + depth);
2018                         if (err)
2019                                 return err;
2020                         unwritten = ext4_ext_is_unwritten(ex);
2021                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2022                                         + ext4_ext_get_actual_len(newext));
2023                         if (unwritten)
2024                                 ext4_ext_mark_unwritten(ex);
2025                         eh = path[depth].p_hdr;
2026                         nearex = ex;
2027                         goto merge;
2028                 }
2029
2030 prepend:
2031                 /* Try to prepend newex to the ex */
2032                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2033                         ext_debug(inode, "prepend %u[%d]%d block to %u:[%d]%d"
2034                                   "(from %llu)\n",
2035                                   le32_to_cpu(newext->ee_block),
2036                                   ext4_ext_is_unwritten(newext),
2037                                   ext4_ext_get_actual_len(newext),
2038                                   le32_to_cpu(ex->ee_block),
2039                                   ext4_ext_is_unwritten(ex),
2040                                   ext4_ext_get_actual_len(ex),
2041                                   ext4_ext_pblock(ex));
2042                         err = ext4_ext_get_access(handle, inode,
2043                                                   path + depth);
2044                         if (err)
2045                                 return err;
2046
2047                         unwritten = ext4_ext_is_unwritten(ex);
2048                         ex->ee_block = newext->ee_block;
2049                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2050                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2051                                         + ext4_ext_get_actual_len(newext));
2052                         if (unwritten)
2053                                 ext4_ext_mark_unwritten(ex);
2054                         eh = path[depth].p_hdr;
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_find_hole - find hole around given block according to the given path
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_find_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_rm_idx:
2268  * removes index from the index block.
2269  */
2270 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2271                         struct ext4_ext_path *path, int depth)
2272 {
2273         int err;
2274         ext4_fsblk_t leaf;
2275
2276         /* free index block */
2277         depth--;
2278         path = path + depth;
2279         leaf = ext4_idx_pblock(path->p_idx);
2280         if (unlikely(path->p_hdr->eh_entries == 0)) {
2281                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2282                 return -EFSCORRUPTED;
2283         }
2284         err = ext4_ext_get_access(handle, inode, path);
2285         if (err)
2286                 return err;
2287
2288         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2289                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2290                 len *= sizeof(struct ext4_extent_idx);
2291                 memmove(path->p_idx, path->p_idx + 1, len);
2292         }
2293
2294         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2295         err = ext4_ext_dirty(handle, inode, path);
2296         if (err)
2297                 return err;
2298         ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
2299         trace_ext4_ext_rm_idx(inode, leaf);
2300
2301         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2302                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2303
2304         while (--depth >= 0) {
2305                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2306                         break;
2307                 path--;
2308                 err = ext4_ext_get_access(handle, inode, path);
2309                 if (err)
2310                         break;
2311                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2312                 err = ext4_ext_dirty(handle, inode, path);
2313                 if (err)
2314                         break;
2315         }
2316         return err;
2317 }
2318
2319 /*
2320  * ext4_ext_calc_credits_for_single_extent:
2321  * This routine returns max. credits that needed to insert an extent
2322  * to the extent tree.
2323  * When pass the actual path, the caller should calculate credits
2324  * under i_data_sem.
2325  */
2326 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2327                                                 struct ext4_ext_path *path)
2328 {
2329         if (path) {
2330                 int depth = ext_depth(inode);
2331                 int ret = 0;
2332
2333                 /* probably there is space in leaf? */
2334                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2335                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2336
2337                         /*
2338                          *  There are some space in the leaf tree, no
2339                          *  need to account for leaf block credit
2340                          *
2341                          *  bitmaps and block group descriptor blocks
2342                          *  and other metadata blocks still need to be
2343                          *  accounted.
2344                          */
2345                         /* 1 bitmap, 1 block group descriptor */
2346                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2347                         return ret;
2348                 }
2349         }
2350
2351         return ext4_chunk_trans_blocks(inode, nrblocks);
2352 }
2353
2354 /*
2355  * How many index/leaf blocks need to change/allocate to add @extents extents?
2356  *
2357  * If we add a single extent, then in the worse case, each tree level
2358  * index/leaf need to be changed in case of the tree split.
2359  *
2360  * If more extents are inserted, they could cause the whole tree split more
2361  * than once, but this is really rare.
2362  */
2363 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2364 {
2365         int index;
2366         int depth;
2367
2368         /* If we are converting the inline data, only one is needed here. */
2369         if (ext4_has_inline_data(inode))
2370                 return 1;
2371
2372         depth = ext_depth(inode);
2373
2374         if (extents <= 1)
2375                 index = depth * 2;
2376         else
2377                 index = depth * 3;
2378
2379         return index;
2380 }
2381
2382 static inline int get_default_free_blocks_flags(struct inode *inode)
2383 {
2384         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2385             ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2386                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2387         else if (ext4_should_journal_data(inode))
2388                 return EXT4_FREE_BLOCKS_FORGET;
2389         return 0;
2390 }
2391
2392 /*
2393  * ext4_rereserve_cluster - increment the reserved cluster count when
2394  *                          freeing a cluster with a pending reservation
2395  *
2396  * @inode - file containing the cluster
2397  * @lblk - logical block in cluster to be reserved
2398  *
2399  * Increments the reserved cluster count and adjusts quota in a bigalloc
2400  * file system when freeing a partial cluster containing at least one
2401  * delayed and unwritten block.  A partial cluster meeting that
2402  * requirement will have a pending reservation.  If so, the
2403  * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2404  * defer reserved and allocated space accounting to a subsequent call
2405  * to this function.
2406  */
2407 static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2408 {
2409         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2410         struct ext4_inode_info *ei = EXT4_I(inode);
2411
2412         dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2413
2414         spin_lock(&ei->i_block_reservation_lock);
2415         ei->i_reserved_data_blocks++;
2416         percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2417         spin_unlock(&ei->i_block_reservation_lock);
2418
2419         percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2420         ext4_remove_pending(inode, lblk);
2421 }
2422
2423 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2424                               struct ext4_extent *ex,
2425                               struct partial_cluster *partial,
2426                               ext4_lblk_t from, ext4_lblk_t to)
2427 {
2428         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2429         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2430         ext4_fsblk_t last_pblk, pblk;
2431         ext4_lblk_t num;
2432         int flags;
2433
2434         /* only extent tail removal is allowed */
2435         if (from < le32_to_cpu(ex->ee_block) ||
2436             to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2437                 ext4_error(sbi->s_sb,
2438                            "strange request: removal(2) %u-%u from %u:%u",
2439                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2440                 return 0;
2441         }
2442
2443 #ifdef EXTENTS_STATS
2444         spin_lock(&sbi->s_ext_stats_lock);
2445         sbi->s_ext_blocks += ee_len;
2446         sbi->s_ext_extents++;
2447         if (ee_len < sbi->s_ext_min)
2448                 sbi->s_ext_min = ee_len;
2449         if (ee_len > sbi->s_ext_max)
2450                 sbi->s_ext_max = ee_len;
2451         if (ext_depth(inode) > sbi->s_depth_max)
2452                 sbi->s_depth_max = ext_depth(inode);
2453         spin_unlock(&sbi->s_ext_stats_lock);
2454 #endif
2455
2456         trace_ext4_remove_blocks(inode, ex, from, to, partial);
2457
2458         /*
2459          * if we have a partial cluster, and it's different from the
2460          * cluster of the last block in the extent, we free it
2461          */
2462         last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2463
2464         if (partial->state != initial &&
2465             partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2466                 if (partial->state == tofree) {
2467                         flags = get_default_free_blocks_flags(inode);
2468                         if (ext4_is_pending(inode, partial->lblk))
2469                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2470                         ext4_free_blocks(handle, inode, NULL,
2471                                          EXT4_C2B(sbi, partial->pclu),
2472                                          sbi->s_cluster_ratio, flags);
2473                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2474                                 ext4_rereserve_cluster(inode, partial->lblk);
2475                 }
2476                 partial->state = initial;
2477         }
2478
2479         num = le32_to_cpu(ex->ee_block) + ee_len - from;
2480         pblk = ext4_ext_pblock(ex) + ee_len - num;
2481
2482         /*
2483          * We free the partial cluster at the end of the extent (if any),
2484          * unless the cluster is used by another extent (partial_cluster
2485          * state is nofree).  If a partial cluster exists here, it must be
2486          * shared with the last block in the extent.
2487          */
2488         flags = get_default_free_blocks_flags(inode);
2489
2490         /* partial, left end cluster aligned, right end unaligned */
2491         if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2492             (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2493             (partial->state != nofree)) {
2494                 if (ext4_is_pending(inode, to))
2495                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2496                 ext4_free_blocks(handle, inode, NULL,
2497                                  EXT4_PBLK_CMASK(sbi, last_pblk),
2498                                  sbi->s_cluster_ratio, flags);
2499                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2500                         ext4_rereserve_cluster(inode, to);
2501                 partial->state = initial;
2502                 flags = get_default_free_blocks_flags(inode);
2503         }
2504
2505         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2506
2507         /*
2508          * For bigalloc file systems, we never free a partial cluster
2509          * at the beginning of the extent.  Instead, we check to see if we
2510          * need to free it on a subsequent call to ext4_remove_blocks,
2511          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2512          */
2513         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2514         ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2515
2516         /* reset the partial cluster if we've freed past it */
2517         if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2518                 partial->state = initial;
2519
2520         /*
2521          * If we've freed the entire extent but the beginning is not left
2522          * cluster aligned and is not marked as ineligible for freeing we
2523          * record the partial cluster at the beginning of the extent.  It
2524          * wasn't freed by the preceding ext4_free_blocks() call, and we
2525          * need to look farther to the left to determine if it's to be freed
2526          * (not shared with another extent). Else, reset the partial
2527          * cluster - we're either  done freeing or the beginning of the
2528          * extent is left cluster aligned.
2529          */
2530         if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2531                 if (partial->state == initial) {
2532                         partial->pclu = EXT4_B2C(sbi, pblk);
2533                         partial->lblk = from;
2534                         partial->state = tofree;
2535                 }
2536         } else {
2537                 partial->state = initial;
2538         }
2539
2540         return 0;
2541 }
2542
2543 /*
2544  * ext4_ext_rm_leaf() Removes the extents associated with the
2545  * blocks appearing between "start" and "end".  Both "start"
2546  * and "end" must appear in the same extent or EIO is returned.
2547  *
2548  * @handle: The journal handle
2549  * @inode:  The files inode
2550  * @path:   The path to the leaf
2551  * @partial_cluster: The cluster which we'll have to free if all extents
2552  *                   has been released from it.  However, if this value is
2553  *                   negative, it's a cluster just to the right of the
2554  *                   punched region and it must not be freed.
2555  * @start:  The first block to remove
2556  * @end:   The last block to remove
2557  */
2558 static int
2559 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2560                  struct ext4_ext_path *path,
2561                  struct partial_cluster *partial,
2562                  ext4_lblk_t start, ext4_lblk_t end)
2563 {
2564         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2565         int err = 0, correct_index = 0;
2566         int depth = ext_depth(inode), credits, revoke_credits;
2567         struct ext4_extent_header *eh;
2568         ext4_lblk_t a, b;
2569         unsigned num;
2570         ext4_lblk_t ex_ee_block;
2571         unsigned short ex_ee_len;
2572         unsigned unwritten = 0;
2573         struct ext4_extent *ex;
2574         ext4_fsblk_t pblk;
2575
2576         /* the header must be checked already in ext4_ext_remove_space() */
2577         ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
2578         if (!path[depth].p_hdr)
2579                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2580         eh = path[depth].p_hdr;
2581         if (unlikely(path[depth].p_hdr == NULL)) {
2582                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2583                 return -EFSCORRUPTED;
2584         }
2585         /* find where to start removing */
2586         ex = path[depth].p_ext;
2587         if (!ex)
2588                 ex = EXT_LAST_EXTENT(eh);
2589
2590         ex_ee_block = le32_to_cpu(ex->ee_block);
2591         ex_ee_len = ext4_ext_get_actual_len(ex);
2592
2593         trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2594
2595         while (ex >= EXT_FIRST_EXTENT(eh) &&
2596                         ex_ee_block + ex_ee_len > start) {
2597
2598                 if (ext4_ext_is_unwritten(ex))
2599                         unwritten = 1;
2600                 else
2601                         unwritten = 0;
2602
2603                 ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
2604                           unwritten, ex_ee_len);
2605                 path[depth].p_ext = ex;
2606
2607                 a = ex_ee_block > start ? ex_ee_block : start;
2608                 b = ex_ee_block+ex_ee_len - 1 < end ?
2609                         ex_ee_block+ex_ee_len - 1 : end;
2610
2611                 ext_debug(inode, "  border %u:%u\n", a, b);
2612
2613                 /* If this extent is beyond the end of the hole, skip it */
2614                 if (end < ex_ee_block) {
2615                         /*
2616                          * We're going to skip this extent and move to another,
2617                          * so note that its first cluster is in use to avoid
2618                          * freeing it when removing blocks.  Eventually, the
2619                          * right edge of the truncated/punched region will
2620                          * be just to the left.
2621                          */
2622                         if (sbi->s_cluster_ratio > 1) {
2623                                 pblk = ext4_ext_pblock(ex);
2624                                 partial->pclu = EXT4_B2C(sbi, pblk);
2625                                 partial->state = nofree;
2626                         }
2627                         ex--;
2628                         ex_ee_block = le32_to_cpu(ex->ee_block);
2629                         ex_ee_len = ext4_ext_get_actual_len(ex);
2630                         continue;
2631                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2632                         EXT4_ERROR_INODE(inode,
2633                                          "can not handle truncate %u:%u "
2634                                          "on extent %u:%u",
2635                                          start, end, ex_ee_block,
2636                                          ex_ee_block + ex_ee_len - 1);
2637                         err = -EFSCORRUPTED;
2638                         goto out;
2639                 } else if (a != ex_ee_block) {
2640                         /* remove tail of the extent */
2641                         num = a - ex_ee_block;
2642                 } else {
2643                         /* remove whole extent: excellent! */
2644                         num = 0;
2645                 }
2646                 /*
2647                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2648                  * descriptor) for each block group; assume two block
2649                  * groups plus ex_ee_len/blocks_per_block_group for
2650                  * the worst case
2651                  */
2652                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2653                 if (ex == EXT_FIRST_EXTENT(eh)) {
2654                         correct_index = 1;
2655                         credits += (ext_depth(inode)) + 1;
2656                 }
2657                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2658                 /*
2659                  * We may end up freeing some index blocks and data from the
2660                  * punched range. Note that partial clusters are accounted for
2661                  * by ext4_free_data_revoke_credits().
2662                  */
2663                 revoke_credits =
2664                         ext4_free_metadata_revoke_credits(inode->i_sb,
2665                                                           ext_depth(inode)) +
2666                         ext4_free_data_revoke_credits(inode, b - a + 1);
2667
2668                 err = ext4_datasem_ensure_credits(handle, inode, credits,
2669                                                   credits, revoke_credits);
2670                 if (err) {
2671                         if (err > 0)
2672                                 err = -EAGAIN;
2673                         goto out;
2674                 }
2675
2676                 err = ext4_ext_get_access(handle, inode, path + depth);
2677                 if (err)
2678                         goto out;
2679
2680                 err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2681                 if (err)
2682                         goto out;
2683
2684                 if (num == 0)
2685                         /* this extent is removed; mark slot entirely unused */
2686                         ext4_ext_store_pblock(ex, 0);
2687
2688                 ex->ee_len = cpu_to_le16(num);
2689                 /*
2690                  * Do not mark unwritten if all the blocks in the
2691                  * extent have been removed.
2692                  */
2693                 if (unwritten && num)
2694                         ext4_ext_mark_unwritten(ex);
2695                 /*
2696                  * If the extent was completely released,
2697                  * we need to remove it from the leaf
2698                  */
2699                 if (num == 0) {
2700                         if (end != EXT_MAX_BLOCKS - 1) {
2701                                 /*
2702                                  * For hole punching, we need to scoot all the
2703                                  * extents up when an extent is removed so that
2704                                  * we dont have blank extents in the middle
2705                                  */
2706                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2707                                         sizeof(struct ext4_extent));
2708
2709                                 /* Now get rid of the one at the end */
2710                                 memset(EXT_LAST_EXTENT(eh), 0,
2711                                         sizeof(struct ext4_extent));
2712                         }
2713                         le16_add_cpu(&eh->eh_entries, -1);
2714                 }
2715
2716                 err = ext4_ext_dirty(handle, inode, path + depth);
2717                 if (err)
2718                         goto out;
2719
2720                 ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
2721                                 ext4_ext_pblock(ex));
2722                 ex--;
2723                 ex_ee_block = le32_to_cpu(ex->ee_block);
2724                 ex_ee_len = ext4_ext_get_actual_len(ex);
2725         }
2726
2727         if (correct_index && eh->eh_entries)
2728                 err = ext4_ext_correct_indexes(handle, inode, path);
2729
2730         /*
2731          * If there's a partial cluster and at least one extent remains in
2732          * the leaf, free the partial cluster if it isn't shared with the
2733          * current extent.  If it is shared with the current extent
2734          * we reset the partial cluster because we've reached the start of the
2735          * truncated/punched region and we're done removing blocks.
2736          */
2737         if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2738                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2739                 if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2740                         int flags = get_default_free_blocks_flags(inode);
2741
2742                         if (ext4_is_pending(inode, partial->lblk))
2743                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2744                         ext4_free_blocks(handle, inode, NULL,
2745                                          EXT4_C2B(sbi, partial->pclu),
2746                                          sbi->s_cluster_ratio, flags);
2747                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2748                                 ext4_rereserve_cluster(inode, partial->lblk);
2749                 }
2750                 partial->state = initial;
2751         }
2752
2753         /* if this leaf is free, then we should
2754          * remove it from index block above */
2755         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2756                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2757
2758 out:
2759         return err;
2760 }
2761
2762 /*
2763  * ext4_ext_more_to_rm:
2764  * returns 1 if current index has to be freed (even partial)
2765  */
2766 static int
2767 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2768 {
2769         BUG_ON(path->p_idx == NULL);
2770
2771         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2772                 return 0;
2773
2774         /*
2775          * if truncate on deeper level happened, it wasn't partial,
2776          * so we have to consider current index for truncation
2777          */
2778         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2779                 return 0;
2780         return 1;
2781 }
2782
2783 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2784                           ext4_lblk_t end)
2785 {
2786         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2787         int depth = ext_depth(inode);
2788         struct ext4_ext_path *path = NULL;
2789         struct partial_cluster partial;
2790         handle_t *handle;
2791         int i = 0, err = 0;
2792
2793         partial.pclu = 0;
2794         partial.lblk = 0;
2795         partial.state = initial;
2796
2797         ext_debug(inode, "truncate since %u to %u\n", start, end);
2798
2799         /* probably first extent we're gonna free will be last in block */
2800         handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2801                         depth + 1,
2802                         ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2803         if (IS_ERR(handle))
2804                 return PTR_ERR(handle);
2805
2806 again:
2807         trace_ext4_ext_remove_space(inode, start, end, depth);
2808
2809         /*
2810          * Check if we are removing extents inside the extent tree. If that
2811          * is the case, we are going to punch a hole inside the extent tree
2812          * so we have to check whether we need to split the extent covering
2813          * the last block to remove so we can easily remove the part of it
2814          * in ext4_ext_rm_leaf().
2815          */
2816         if (end < EXT_MAX_BLOCKS - 1) {
2817                 struct ext4_extent *ex;
2818                 ext4_lblk_t ee_block, ex_end, lblk;
2819                 ext4_fsblk_t pblk;
2820
2821                 /* find extent for or closest extent to this block */
2822                 path = ext4_find_extent(inode, end, NULL,
2823                                         EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
2824                 if (IS_ERR(path)) {
2825                         ext4_journal_stop(handle);
2826                         return PTR_ERR(path);
2827                 }
2828                 depth = ext_depth(inode);
2829                 /* Leaf not may not exist only if inode has no blocks at all */
2830                 ex = path[depth].p_ext;
2831                 if (!ex) {
2832                         if (depth) {
2833                                 EXT4_ERROR_INODE(inode,
2834                                                  "path[%d].p_hdr == NULL",
2835                                                  depth);
2836                                 err = -EFSCORRUPTED;
2837                         }
2838                         goto out;
2839                 }
2840
2841                 ee_block = le32_to_cpu(ex->ee_block);
2842                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2843
2844                 /*
2845                  * See if the last block is inside the extent, if so split
2846                  * the extent at 'end' block so we can easily remove the
2847                  * tail of the first part of the split extent in
2848                  * ext4_ext_rm_leaf().
2849                  */
2850                 if (end >= ee_block && end < ex_end) {
2851
2852                         /*
2853                          * If we're going to split the extent, note that
2854                          * the cluster containing the block after 'end' is
2855                          * in use to avoid freeing it when removing blocks.
2856                          */
2857                         if (sbi->s_cluster_ratio > 1) {
2858                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
2859                                 partial.pclu = EXT4_B2C(sbi, pblk);
2860                                 partial.state = nofree;
2861                         }
2862
2863                         /*
2864                          * Split the extent in two so that 'end' is the last
2865                          * block in the first new extent. Also we should not
2866                          * fail removing space due to ENOSPC so try to use
2867                          * reserved block if that happens.
2868                          */
2869                         err = ext4_force_split_extent_at(handle, inode, &path,
2870                                                          end + 1, 1);
2871                         if (err < 0)
2872                                 goto out;
2873
2874                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
2875                            partial.state == initial) {
2876                         /*
2877                          * If we're punching, there's an extent to the right.
2878                          * If the partial cluster hasn't been set, set it to
2879                          * that extent's first cluster and its state to nofree
2880                          * so it won't be freed should it contain blocks to be
2881                          * removed. If it's already set (tofree/nofree), we're
2882                          * retrying and keep the original partial cluster info
2883                          * so a cluster marked tofree as a result of earlier
2884                          * extent removal is not lost.
2885                          */
2886                         lblk = ex_end + 1;
2887                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2888                                                     NULL);
2889                         if (err < 0)
2890                                 goto out;
2891                         if (pblk) {
2892                                 partial.pclu = EXT4_B2C(sbi, pblk);
2893                                 partial.state = nofree;
2894                         }
2895                 }
2896         }
2897         /*
2898          * We start scanning from right side, freeing all the blocks
2899          * after i_size and walking into the tree depth-wise.
2900          */
2901         depth = ext_depth(inode);
2902         if (path) {
2903                 int k = i = depth;
2904                 while (--k > 0)
2905                         path[k].p_block =
2906                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2907         } else {
2908                 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
2909                                GFP_NOFS | __GFP_NOFAIL);
2910                 if (path == NULL) {
2911                         ext4_journal_stop(handle);
2912                         return -ENOMEM;
2913                 }
2914                 path[0].p_maxdepth = path[0].p_depth = depth;
2915                 path[0].p_hdr = ext_inode_hdr(inode);
2916                 i = 0;
2917
2918                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2919                         err = -EFSCORRUPTED;
2920                         goto out;
2921                 }
2922         }
2923         err = 0;
2924
2925         while (i >= 0 && err == 0) {
2926                 if (i == depth) {
2927                         /* this is leaf block */
2928                         err = ext4_ext_rm_leaf(handle, inode, path,
2929                                                &partial, start, end);
2930                         /* root level has p_bh == NULL, brelse() eats this */
2931                         brelse(path[i].p_bh);
2932                         path[i].p_bh = NULL;
2933                         i--;
2934                         continue;
2935                 }
2936
2937                 /* this is index block */
2938                 if (!path[i].p_hdr) {
2939                         ext_debug(inode, "initialize header\n");
2940                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2941                 }
2942
2943                 if (!path[i].p_idx) {
2944                         /* this level hasn't been touched yet */
2945                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2946                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2947                         ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
2948                                   path[i].p_hdr,
2949                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2950                 } else {
2951                         /* we were already here, see at next index */
2952                         path[i].p_idx--;
2953                 }
2954
2955                 ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
2956                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2957                                 path[i].p_idx);
2958                 if (ext4_ext_more_to_rm(path + i)) {
2959                         struct buffer_head *bh;
2960                         /* go to the next level */
2961                         ext_debug(inode, "move to level %d (block %llu)\n",
2962                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2963                         memset(path + i + 1, 0, sizeof(*path));
2964                         bh = read_extent_tree_block(inode, path[i].p_idx,
2965                                                     depth - i - 1,
2966                                                     EXT4_EX_NOCACHE);
2967                         if (IS_ERR(bh)) {
2968                                 /* should we reset i_size? */
2969                                 err = PTR_ERR(bh);
2970                                 break;
2971                         }
2972                         /* Yield here to deal with large extent trees.
2973                          * Should be a no-op if we did IO above. */
2974                         cond_resched();
2975                         if (WARN_ON(i + 1 > depth)) {
2976                                 err = -EFSCORRUPTED;
2977                                 break;
2978                         }
2979                         path[i + 1].p_bh = bh;
2980
2981                         /* save actual number of indexes since this
2982                          * number is changed at the next iteration */
2983                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2984                         i++;
2985                 } else {
2986                         /* we finished processing this index, go up */
2987                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2988                                 /* index is empty, remove it;
2989                                  * handle must be already prepared by the
2990                                  * truncatei_leaf() */
2991                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2992                         }
2993                         /* root level has p_bh == NULL, brelse() eats this */
2994                         brelse(path[i].p_bh);
2995                         path[i].p_bh = NULL;
2996                         i--;
2997                         ext_debug(inode, "return to level %d\n", i);
2998                 }
2999         }
3000
3001         trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3002                                          path->p_hdr->eh_entries);
3003
3004         /*
3005          * if there's a partial cluster and we have removed the first extent
3006          * in the file, then we also free the partial cluster, if any
3007          */
3008         if (partial.state == tofree && err == 0) {
3009                 int flags = get_default_free_blocks_flags(inode);
3010
3011                 if (ext4_is_pending(inode, partial.lblk))
3012                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3013                 ext4_free_blocks(handle, inode, NULL,
3014                                  EXT4_C2B(sbi, partial.pclu),
3015                                  sbi->s_cluster_ratio, flags);
3016                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3017                         ext4_rereserve_cluster(inode, partial.lblk);
3018                 partial.state = initial;
3019         }
3020
3021         /* TODO: flexible tree reduction should be here */
3022         if (path->p_hdr->eh_entries == 0) {
3023                 /*
3024                  * truncate to zero freed all the tree,
3025                  * so we need to correct eh_depth
3026                  */
3027                 err = ext4_ext_get_access(handle, inode, path);
3028                 if (err == 0) {
3029                         ext_inode_hdr(inode)->eh_depth = 0;
3030                         ext_inode_hdr(inode)->eh_max =
3031                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3032                         err = ext4_ext_dirty(handle, inode, path);
3033                 }
3034         }
3035 out:
3036         ext4_ext_drop_refs(path);
3037         kfree(path);
3038         path = NULL;
3039         if (err == -EAGAIN)
3040                 goto again;
3041         ext4_journal_stop(handle);
3042
3043         return err;
3044 }
3045
3046 /*
3047  * called at mount time
3048  */
3049 void ext4_ext_init(struct super_block *sb)
3050 {
3051         /*
3052          * possible initialization would be here
3053          */
3054
3055         if (ext4_has_feature_extents(sb)) {
3056 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3057                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3058 #ifdef AGGRESSIVE_TEST
3059                        ", aggressive tests"
3060 #endif
3061 #ifdef CHECK_BINSEARCH
3062                        ", check binsearch"
3063 #endif
3064 #ifdef EXTENTS_STATS
3065                        ", stats"
3066 #endif
3067                        "\n");
3068 #endif
3069 #ifdef EXTENTS_STATS
3070                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3071                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3072                 EXT4_SB(sb)->s_ext_max = 0;
3073 #endif
3074         }
3075 }
3076
3077 /*
3078  * called at umount time
3079  */
3080 void ext4_ext_release(struct super_block *sb)
3081 {
3082         if (!ext4_has_feature_extents(sb))
3083                 return;
3084
3085 #ifdef EXTENTS_STATS
3086         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3087                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3088                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3089                         sbi->s_ext_blocks, sbi->s_ext_extents,
3090                         sbi->s_ext_blocks / sbi->s_ext_extents);
3091                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3092                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3093         }
3094 #endif
3095 }
3096
3097 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3098 {
3099         ext4_lblk_t  ee_block;
3100         ext4_fsblk_t ee_pblock;
3101         unsigned int ee_len;
3102
3103         ee_block  = le32_to_cpu(ex->ee_block);
3104         ee_len    = ext4_ext_get_actual_len(ex);
3105         ee_pblock = ext4_ext_pblock(ex);
3106
3107         if (ee_len == 0)
3108                 return 0;
3109
3110         ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3111                               EXTENT_STATUS_WRITTEN);
3112         return 0;
3113 }
3114
3115 /* FIXME!! we need to try to merge to left or right after zero-out  */
3116 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3117 {
3118         ext4_fsblk_t ee_pblock;
3119         unsigned int ee_len;
3120
3121         ee_len    = ext4_ext_get_actual_len(ex);
3122         ee_pblock = ext4_ext_pblock(ex);
3123         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3124                                   ee_len);
3125 }
3126
3127 /*
3128  * ext4_split_extent_at() splits an extent at given block.
3129  *
3130  * @handle: the journal handle
3131  * @inode: the file inode
3132  * @path: the path to the extent
3133  * @split: the logical block where the extent is splitted.
3134  * @split_flags: indicates if the extent could be zeroout if split fails, and
3135  *               the states(init or unwritten) of new extents.
3136  * @flags: flags used to insert new extent to extent tree.
3137  *
3138  *
3139  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3140  * of which are determined by split_flag.
3141  *
3142  * There are two cases:
3143  *  a> the extent are splitted into two extent.
3144  *  b> split is not needed, and just mark the extent.
3145  *
3146  * return 0 on success.
3147  */
3148 static int ext4_split_extent_at(handle_t *handle,
3149                              struct inode *inode,
3150                              struct ext4_ext_path **ppath,
3151                              ext4_lblk_t split,
3152                              int split_flag,
3153                              int flags)
3154 {
3155         struct ext4_ext_path *path = *ppath;
3156         ext4_fsblk_t newblock;
3157         ext4_lblk_t ee_block;
3158         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3159         struct ext4_extent *ex2 = NULL;
3160         unsigned int ee_len, depth;
3161         int err = 0;
3162
3163         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3164                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3165
3166         ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
3167
3168         ext4_ext_show_leaf(inode, path);
3169
3170         depth = ext_depth(inode);
3171         ex = path[depth].p_ext;
3172         ee_block = le32_to_cpu(ex->ee_block);
3173         ee_len = ext4_ext_get_actual_len(ex);
3174         newblock = split - ee_block + ext4_ext_pblock(ex);
3175
3176         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3177         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3178                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3179                              EXT4_EXT_MARK_UNWRIT1 |
3180                              EXT4_EXT_MARK_UNWRIT2));
3181
3182         err = ext4_ext_get_access(handle, inode, path + depth);
3183         if (err)
3184                 goto out;
3185
3186         if (split == ee_block) {
3187                 /*
3188                  * case b: block @split is the block that the extent begins with
3189                  * then we just change the state of the extent, and splitting
3190                  * is not needed.
3191                  */
3192                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3193                         ext4_ext_mark_unwritten(ex);
3194                 else
3195                         ext4_ext_mark_initialized(ex);
3196
3197                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3198                         ext4_ext_try_to_merge(handle, inode, path, ex);
3199
3200                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3201                 goto out;
3202         }
3203
3204         /* case a */
3205         memcpy(&orig_ex, ex, sizeof(orig_ex));
3206         ex->ee_len = cpu_to_le16(split - ee_block);
3207         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3208                 ext4_ext_mark_unwritten(ex);
3209
3210         /*
3211          * path may lead to new leaf, not to original leaf any more
3212          * after ext4_ext_insert_extent() returns,
3213          */
3214         err = ext4_ext_dirty(handle, inode, path + depth);
3215         if (err)
3216                 goto fix_extent_len;
3217
3218         ex2 = &newex;
3219         ex2->ee_block = cpu_to_le32(split);
3220         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3221         ext4_ext_store_pblock(ex2, newblock);
3222         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3223                 ext4_ext_mark_unwritten(ex2);
3224
3225         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3226         if (err != -ENOSPC && err != -EDQUOT)
3227                 goto out;
3228
3229         if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
3230                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3231                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3232                                 err = ext4_ext_zeroout(inode, ex2);
3233                                 zero_ex.ee_block = ex2->ee_block;
3234                                 zero_ex.ee_len = cpu_to_le16(
3235                                                 ext4_ext_get_actual_len(ex2));
3236                                 ext4_ext_store_pblock(&zero_ex,
3237                                                       ext4_ext_pblock(ex2));
3238                         } else {
3239                                 err = ext4_ext_zeroout(inode, ex);
3240                                 zero_ex.ee_block = ex->ee_block;
3241                                 zero_ex.ee_len = cpu_to_le16(
3242                                                 ext4_ext_get_actual_len(ex));
3243                                 ext4_ext_store_pblock(&zero_ex,
3244                                                       ext4_ext_pblock(ex));
3245                         }
3246                 } else {
3247                         err = ext4_ext_zeroout(inode, &orig_ex);
3248                         zero_ex.ee_block = orig_ex.ee_block;
3249                         zero_ex.ee_len = cpu_to_le16(
3250                                                 ext4_ext_get_actual_len(&orig_ex));
3251                         ext4_ext_store_pblock(&zero_ex,
3252                                               ext4_ext_pblock(&orig_ex));
3253                 }
3254
3255                 if (!err) {
3256                         /* update the extent length and mark as initialized */
3257                         ex->ee_len = cpu_to_le16(ee_len);
3258                         ext4_ext_try_to_merge(handle, inode, path, ex);
3259                         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3260                         if (!err)
3261                                 /* update extent status tree */
3262                                 err = ext4_zeroout_es(inode, &zero_ex);
3263                         /* If we failed at this point, we don't know in which
3264                          * state the extent tree exactly is so don't try to fix
3265                          * length of the original extent as it may do even more
3266                          * damage.
3267                          */
3268                         goto out;
3269                 }
3270         }
3271
3272 fix_extent_len:
3273         ex->ee_len = orig_ex.ee_len;
3274         /*
3275          * Ignore ext4_ext_dirty return value since we are already in error path
3276          * and err is a non-zero error code.
3277          */
3278         ext4_ext_dirty(handle, inode, path + path->p_depth);
3279         return err;
3280 out:
3281         ext4_ext_show_leaf(inode, path);
3282         return err;
3283 }
3284
3285 /*
3286  * ext4_split_extents() splits an extent and mark extent which is covered
3287  * by @map as split_flags indicates
3288  *
3289  * It may result in splitting the extent into multiple extents (up to three)
3290  * There are three possibilities:
3291  *   a> There is no split required
3292  *   b> Splits in two extents: Split is happening at either end of the extent
3293  *   c> Splits in three extents: Somone is splitting in middle of the extent
3294  *
3295  */
3296 static int ext4_split_extent(handle_t *handle,
3297                               struct inode *inode,
3298                               struct ext4_ext_path **ppath,
3299                               struct ext4_map_blocks *map,
3300                               int split_flag,
3301                               int flags)
3302 {
3303         struct ext4_ext_path *path = *ppath;
3304         ext4_lblk_t ee_block;
3305         struct ext4_extent *ex;
3306         unsigned int ee_len, depth;
3307         int err = 0;
3308         int unwritten;
3309         int split_flag1, flags1;
3310         int allocated = map->m_len;
3311
3312         depth = ext_depth(inode);
3313         ex = path[depth].p_ext;
3314         ee_block = le32_to_cpu(ex->ee_block);
3315         ee_len = ext4_ext_get_actual_len(ex);
3316         unwritten = ext4_ext_is_unwritten(ex);
3317
3318         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3319                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3320                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3321                 if (unwritten)
3322                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3323                                        EXT4_EXT_MARK_UNWRIT2;
3324                 if (split_flag & EXT4_EXT_DATA_VALID2)
3325                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3326                 err = ext4_split_extent_at(handle, inode, ppath,
3327                                 map->m_lblk + map->m_len, split_flag1, flags1);
3328                 if (err)
3329                         goto out;
3330         } else {
3331                 allocated = ee_len - (map->m_lblk - ee_block);
3332         }
3333         /*
3334          * Update path is required because previous ext4_split_extent_at() may
3335          * result in split of original leaf or extent zeroout.
3336          */
3337         path = ext4_find_extent(inode, map->m_lblk, ppath, flags);
3338         if (IS_ERR(path))
3339                 return PTR_ERR(path);
3340         depth = ext_depth(inode);
3341         ex = path[depth].p_ext;
3342         if (!ex) {
3343                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3344                                  (unsigned long) map->m_lblk);
3345                 return -EFSCORRUPTED;
3346         }
3347         unwritten = ext4_ext_is_unwritten(ex);
3348         split_flag1 = 0;
3349
3350         if (map->m_lblk >= ee_block) {
3351                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3352                 if (unwritten) {
3353                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3354                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3355                                                      EXT4_EXT_MARK_UNWRIT2);
3356                 }
3357                 err = ext4_split_extent_at(handle, inode, ppath,
3358                                 map->m_lblk, split_flag1, flags);
3359                 if (err)
3360                         goto out;
3361         }
3362
3363         ext4_ext_show_leaf(inode, path);
3364 out:
3365         return err ? err : allocated;
3366 }
3367
3368 /*
3369  * This function is called by ext4_ext_map_blocks() if someone tries to write
3370  * to an unwritten extent. It may result in splitting the unwritten
3371  * extent into multiple extents (up to three - one initialized and two
3372  * unwritten).
3373  * There are three possibilities:
3374  *   a> There is no split required: Entire extent should be initialized
3375  *   b> Splits in two extents: Write is happening at either end of the extent
3376  *   c> Splits in three extents: Somone is writing in middle of the extent
3377  *
3378  * Pre-conditions:
3379  *  - The extent pointed to by 'path' is unwritten.
3380  *  - The extent pointed to by 'path' contains a superset
3381  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3382  *
3383  * Post-conditions on success:
3384  *  - the returned value is the number of blocks beyond map->l_lblk
3385  *    that are allocated and initialized.
3386  *    It is guaranteed to be >= map->m_len.
3387  */
3388 static int ext4_ext_convert_to_initialized(handle_t *handle,
3389                                            struct inode *inode,
3390                                            struct ext4_map_blocks *map,
3391                                            struct ext4_ext_path **ppath,
3392                                            int flags)
3393 {
3394         struct ext4_ext_path *path = *ppath;
3395         struct ext4_sb_info *sbi;
3396         struct ext4_extent_header *eh;
3397         struct ext4_map_blocks split_map;
3398         struct ext4_extent zero_ex1, zero_ex2;
3399         struct ext4_extent *ex, *abut_ex;
3400         ext4_lblk_t ee_block, eof_block;
3401         unsigned int ee_len, depth, map_len = map->m_len;
3402         int allocated = 0, max_zeroout = 0;
3403         int err = 0;
3404         int split_flag = EXT4_EXT_DATA_VALID2;
3405
3406         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3407                   (unsigned long long)map->m_lblk, map_len);
3408
3409         sbi = EXT4_SB(inode->i_sb);
3410         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3411                         >> inode->i_sb->s_blocksize_bits;
3412         if (eof_block < map->m_lblk + map_len)
3413                 eof_block = map->m_lblk + map_len;
3414
3415         depth = ext_depth(inode);
3416         eh = path[depth].p_hdr;
3417         ex = path[depth].p_ext;
3418         ee_block = le32_to_cpu(ex->ee_block);
3419         ee_len = ext4_ext_get_actual_len(ex);
3420         zero_ex1.ee_len = 0;
3421         zero_ex2.ee_len = 0;
3422
3423         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3424
3425         /* Pre-conditions */
3426         BUG_ON(!ext4_ext_is_unwritten(ex));
3427         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3428
3429         /*
3430          * Attempt to transfer newly initialized blocks from the currently
3431          * unwritten extent to its neighbor. This is much cheaper
3432          * than an insertion followed by a merge as those involve costly
3433          * memmove() calls. Transferring to the left is the common case in
3434          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3435          * followed by append writes.
3436          *
3437          * Limitations of the current logic:
3438          *  - L1: we do not deal with writes covering the whole extent.
3439          *    This would require removing the extent if the transfer
3440          *    is possible.
3441          *  - L2: we only attempt to merge with an extent stored in the
3442          *    same extent tree node.
3443          */
3444         if ((map->m_lblk == ee_block) &&
3445                 /* See if we can merge left */
3446                 (map_len < ee_len) &&           /*L1*/
3447                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3448                 ext4_lblk_t prev_lblk;
3449                 ext4_fsblk_t prev_pblk, ee_pblk;
3450                 unsigned int prev_len;
3451
3452                 abut_ex = ex - 1;
3453                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3454                 prev_len = ext4_ext_get_actual_len(abut_ex);
3455                 prev_pblk = ext4_ext_pblock(abut_ex);
3456                 ee_pblk = ext4_ext_pblock(ex);
3457
3458                 /*
3459                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3460                  * upon those conditions:
3461                  * - C1: abut_ex is initialized,
3462                  * - C2: abut_ex is logically abutting ex,
3463                  * - C3: abut_ex is physically abutting ex,
3464                  * - C4: abut_ex can receive the additional blocks without
3465                  *   overflowing the (initialized) length limit.
3466                  */
3467                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3468                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3469                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3470                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3471                         err = ext4_ext_get_access(handle, inode, path + depth);
3472                         if (err)
3473                                 goto out;
3474
3475                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3476                                 map, ex, abut_ex);
3477
3478                         /* Shift the start of ex by 'map_len' blocks */
3479                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3480                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3481                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3482                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3483
3484                         /* Extend abut_ex by 'map_len' blocks */
3485                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3486
3487                         /* Result: number of initialized blocks past m_lblk */
3488                         allocated = map_len;
3489                 }
3490         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3491                    (map_len < ee_len) &&        /*L1*/
3492                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3493                 /* See if we can merge right */
3494                 ext4_lblk_t next_lblk;
3495                 ext4_fsblk_t next_pblk, ee_pblk;
3496                 unsigned int next_len;
3497
3498                 abut_ex = ex + 1;
3499                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3500                 next_len = ext4_ext_get_actual_len(abut_ex);
3501                 next_pblk = ext4_ext_pblock(abut_ex);
3502                 ee_pblk = ext4_ext_pblock(ex);
3503
3504                 /*
3505                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3506                  * upon those conditions:
3507                  * - C1: abut_ex is initialized,
3508                  * - C2: abut_ex is logically abutting ex,
3509                  * - C3: abut_ex is physically abutting ex,
3510                  * - C4: abut_ex can receive the additional blocks without
3511                  *   overflowing the (initialized) length limit.
3512                  */
3513                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3514                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3515                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3516                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3517                         err = ext4_ext_get_access(handle, inode, path + depth);
3518                         if (err)
3519                                 goto out;
3520
3521                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3522                                 map, ex, abut_ex);
3523
3524                         /* Shift the start of abut_ex by 'map_len' blocks */
3525                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3526                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3527                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3528                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3529
3530                         /* Extend abut_ex by 'map_len' blocks */
3531                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3532
3533                         /* Result: number of initialized blocks past m_lblk */
3534                         allocated = map_len;
3535                 }
3536         }
3537         if (allocated) {
3538                 /* Mark the block containing both extents as dirty */
3539                 err = ext4_ext_dirty(handle, inode, path + depth);
3540
3541                 /* Update path to point to the right extent */
3542                 path[depth].p_ext = abut_ex;
3543                 goto out;
3544         } else
3545                 allocated = ee_len - (map->m_lblk - ee_block);
3546
3547         WARN_ON(map->m_lblk < ee_block);
3548         /*
3549          * It is safe to convert extent to initialized via explicit
3550          * zeroout only if extent is fully inside i_size or new_size.
3551          */
3552         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3553
3554         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3555                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3556                         (inode->i_sb->s_blocksize_bits - 10);
3557
3558         /*
3559          * five cases:
3560          * 1. split the extent into three extents.
3561          * 2. split the extent into two extents, zeroout the head of the first
3562          *    extent.
3563          * 3. split the extent into two extents, zeroout the tail of the second
3564          *    extent.
3565          * 4. split the extent into two extents with out zeroout.
3566          * 5. no splitting needed, just possibly zeroout the head and / or the
3567          *    tail of the extent.
3568          */
3569         split_map.m_lblk = map->m_lblk;
3570         split_map.m_len = map->m_len;
3571
3572         if (max_zeroout && (allocated > split_map.m_len)) {
3573                 if (allocated <= max_zeroout) {
3574                         /* case 3 or 5 */
3575                         zero_ex1.ee_block =
3576                                  cpu_to_le32(split_map.m_lblk +
3577                                              split_map.m_len);
3578                         zero_ex1.ee_len =
3579                                 cpu_to_le16(allocated - split_map.m_len);
3580                         ext4_ext_store_pblock(&zero_ex1,
3581                                 ext4_ext_pblock(ex) + split_map.m_lblk +
3582                                 split_map.m_len - ee_block);
3583                         err = ext4_ext_zeroout(inode, &zero_ex1);
3584                         if (err)
3585                                 goto out;
3586                         split_map.m_len = allocated;
3587                 }
3588                 if (split_map.m_lblk - ee_block + split_map.m_len <
3589                                                                 max_zeroout) {
3590                         /* case 2 or 5 */
3591                         if (split_map.m_lblk != ee_block) {
3592                                 zero_ex2.ee_block = ex->ee_block;
3593                                 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3594                                                         ee_block);
3595                                 ext4_ext_store_pblock(&zero_ex2,
3596                                                       ext4_ext_pblock(ex));
3597                                 err = ext4_ext_zeroout(inode, &zero_ex2);
3598                                 if (err)
3599                                         goto out;
3600                         }
3601
3602                         split_map.m_len += split_map.m_lblk - ee_block;
3603                         split_map.m_lblk = ee_block;
3604                         allocated = map->m_len;
3605                 }
3606         }
3607
3608         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3609                                 flags);
3610         if (err > 0)
3611                 err = 0;
3612 out:
3613         /* If we have gotten a failure, don't zero out status tree */
3614         if (!err) {
3615                 err = ext4_zeroout_es(inode, &zero_ex1);
3616                 if (!err)
3617                         err = ext4_zeroout_es(inode, &zero_ex2);
3618         }
3619         return err ? err : allocated;
3620 }
3621
3622 /*
3623  * This function is called by ext4_ext_map_blocks() from
3624  * ext4_get_blocks_dio_write() when DIO to write
3625  * to an unwritten extent.
3626  *
3627  * Writing to an unwritten extent may result in splitting the unwritten
3628  * extent into multiple initialized/unwritten extents (up to three)
3629  * There are three possibilities:
3630  *   a> There is no split required: Entire extent should be unwritten
3631  *   b> Splits in two extents: Write is happening at either end of the extent
3632  *   c> Splits in three extents: Somone is writing in middle of the extent
3633  *
3634  * This works the same way in the case of initialized -> unwritten conversion.
3635  *
3636  * One of more index blocks maybe needed if the extent tree grow after
3637  * the unwritten extent split. To prevent ENOSPC occur at the IO
3638  * complete, we need to split the unwritten extent before DIO submit
3639  * the IO. The unwritten extent called at this time will be split
3640  * into three unwritten extent(at most). After IO complete, the part
3641  * being filled will be convert to initialized by the end_io callback function
3642  * via ext4_convert_unwritten_extents().
3643  *
3644  * Returns the size of unwritten extent to be written on success.
3645  */
3646 static int ext4_split_convert_extents(handle_t *handle,
3647                                         struct inode *inode,
3648                                         struct ext4_map_blocks *map,
3649                                         struct ext4_ext_path **ppath,
3650                                         int flags)
3651 {
3652         struct ext4_ext_path *path = *ppath;
3653         ext4_lblk_t eof_block;
3654         ext4_lblk_t ee_block;
3655         struct ext4_extent *ex;
3656         unsigned int ee_len;
3657         int split_flag = 0, depth;
3658
3659         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3660                   (unsigned long long)map->m_lblk, map->m_len);
3661
3662         eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3663                         >> inode->i_sb->s_blocksize_bits;
3664         if (eof_block < map->m_lblk + map->m_len)
3665                 eof_block = map->m_lblk + map->m_len;
3666         /*
3667          * It is safe to convert extent to initialized via explicit
3668          * zeroout only if extent is fully inside i_size or new_size.
3669          */
3670         depth = ext_depth(inode);
3671         ex = path[depth].p_ext;
3672         ee_block = le32_to_cpu(ex->ee_block);
3673         ee_len = ext4_ext_get_actual_len(ex);
3674
3675         /* Convert to unwritten */
3676         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3677                 split_flag |= EXT4_EXT_DATA_VALID1;
3678         /* Convert to initialized */
3679         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3680                 split_flag |= ee_block + ee_len <= eof_block ?
3681                               EXT4_EXT_MAY_ZEROOUT : 0;
3682                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3683         }
3684         flags |= EXT4_GET_BLOCKS_PRE_IO;
3685         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3686 }
3687
3688 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3689                                                 struct inode *inode,
3690                                                 struct ext4_map_blocks *map,
3691                                                 struct ext4_ext_path **ppath)
3692 {
3693         struct ext4_ext_path *path = *ppath;
3694         struct ext4_extent *ex;
3695         ext4_lblk_t ee_block;
3696         unsigned int ee_len;
3697         int depth;
3698         int err = 0;
3699
3700         depth = ext_depth(inode);
3701         ex = path[depth].p_ext;
3702         ee_block = le32_to_cpu(ex->ee_block);
3703         ee_len = ext4_ext_get_actual_len(ex);
3704
3705         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3706                   (unsigned long long)ee_block, ee_len);
3707
3708         /* If extent is larger than requested it is a clear sign that we still
3709          * have some extent state machine issues left. So extent_split is still
3710          * required.
3711          * TODO: Once all related issues will be fixed this situation should be
3712          * illegal.
3713          */
3714         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3715 #ifdef CONFIG_EXT4_DEBUG
3716                 ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3717                              " len %u; IO logical block %llu, len %u",
3718                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3719                              (unsigned long long)map->m_lblk, map->m_len);
3720 #endif
3721                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3722                                                  EXT4_GET_BLOCKS_CONVERT);
3723                 if (err < 0)
3724                         return err;
3725                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3726                 if (IS_ERR(path))
3727                         return PTR_ERR(path);
3728                 depth = ext_depth(inode);
3729                 ex = path[depth].p_ext;
3730         }
3731
3732         err = ext4_ext_get_access(handle, inode, path + depth);
3733         if (err)
3734                 goto out;
3735         /* first mark the extent as initialized */
3736         ext4_ext_mark_initialized(ex);
3737
3738         /* note: ext4_ext_correct_indexes() isn't needed here because
3739          * borders are not changed
3740          */
3741         ext4_ext_try_to_merge(handle, inode, path, ex);
3742
3743         /* Mark modified extent as dirty */
3744         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3745 out:
3746         ext4_ext_show_leaf(inode, path);
3747         return err;
3748 }
3749
3750 static int
3751 convert_initialized_extent(handle_t *handle, struct inode *inode,
3752                            struct ext4_map_blocks *map,
3753                            struct ext4_ext_path **ppath,
3754                            unsigned int *allocated)
3755 {
3756         struct ext4_ext_path *path = *ppath;
3757         struct ext4_extent *ex;
3758         ext4_lblk_t ee_block;
3759         unsigned int ee_len;
3760         int depth;
3761         int err = 0;
3762
3763         /*
3764          * Make sure that the extent is no bigger than we support with
3765          * unwritten extent
3766          */
3767         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3768                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3769
3770         depth = ext_depth(inode);
3771         ex = path[depth].p_ext;
3772         ee_block = le32_to_cpu(ex->ee_block);
3773         ee_len = ext4_ext_get_actual_len(ex);
3774
3775         ext_debug(inode, "logical block %llu, max_blocks %u\n",
3776                   (unsigned long long)ee_block, ee_len);
3777
3778         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3779                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3780                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3781                 if (err < 0)
3782                         return err;
3783                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3784                 if (IS_ERR(path))
3785                         return PTR_ERR(path);
3786                 depth = ext_depth(inode);
3787                 ex = path[depth].p_ext;
3788                 if (!ex) {
3789                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3790                                          (unsigned long) map->m_lblk);
3791                         return -EFSCORRUPTED;
3792                 }
3793         }
3794
3795         err = ext4_ext_get_access(handle, inode, path + depth);
3796         if (err)
3797                 return err;
3798         /* first mark the extent as unwritten */
3799         ext4_ext_mark_unwritten(ex);
3800
3801         /* note: ext4_ext_correct_indexes() isn't needed here because
3802          * borders are not changed
3803          */
3804         ext4_ext_try_to_merge(handle, inode, path, ex);
3805
3806         /* Mark modified extent as dirty */
3807         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3808         if (err)
3809                 return err;
3810         ext4_ext_show_leaf(inode, path);
3811
3812         ext4_update_inode_fsync_trans(handle, inode, 1);
3813
3814         map->m_flags |= EXT4_MAP_UNWRITTEN;
3815         if (*allocated > map->m_len)
3816                 *allocated = map->m_len;
3817         map->m_len = *allocated;
3818         return 0;
3819 }
3820
3821 static int
3822 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3823                         struct ext4_map_blocks *map,
3824                         struct ext4_ext_path **ppath, int flags,
3825                         unsigned int allocated, ext4_fsblk_t newblock)
3826 {
3827         struct ext4_ext_path __maybe_unused *path = *ppath;
3828         int ret = 0;
3829         int err = 0;
3830
3831         ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
3832                   (unsigned long long)map->m_lblk, map->m_len, flags,
3833                   allocated);
3834         ext4_ext_show_leaf(inode, path);
3835
3836         /*
3837          * When writing into unwritten space, we should not fail to
3838          * allocate metadata blocks for the new extent block if needed.
3839          */
3840         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3841
3842         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
3843                                                     allocated, newblock);
3844
3845         /* get_block() before submitting IO, split the extent */
3846         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
3847                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
3848                                          flags | EXT4_GET_BLOCKS_CONVERT);
3849                 if (ret < 0) {
3850                         err = ret;
3851                         goto out2;
3852                 }
3853                 /*
3854                  * shouldn't get a 0 return when splitting an extent unless
3855                  * m_len is 0 (bug) or extent has been corrupted
3856                  */
3857                 if (unlikely(ret == 0)) {
3858                         EXT4_ERROR_INODE(inode,
3859                                          "unexpected ret == 0, m_len = %u",
3860                                          map->m_len);
3861                         err = -EFSCORRUPTED;
3862                         goto out2;
3863                 }
3864                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3865                 goto out;
3866         }
3867         /* IO end_io complete, convert the filled extent to written */
3868         if (flags & EXT4_GET_BLOCKS_CONVERT) {
3869                 err = ext4_convert_unwritten_extents_endio(handle, inode, map,
3870                                                            ppath);
3871                 if (err < 0)
3872                         goto out2;
3873                 ext4_update_inode_fsync_trans(handle, inode, 1);
3874                 goto map_out;
3875         }
3876         /* buffered IO cases */
3877         /*
3878          * repeat fallocate creation request
3879          * we already have an unwritten extent
3880          */
3881         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
3882                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3883                 goto map_out;
3884         }
3885
3886         /* buffered READ or buffered write_begin() lookup */
3887         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3888                 /*
3889                  * We have blocks reserved already.  We
3890                  * return allocated blocks so that delalloc
3891                  * won't do block reservation for us.  But
3892                  * the buffer head will be unmapped so that
3893                  * a read from the block returns 0s.
3894                  */
3895                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3896                 goto out1;
3897         }
3898
3899         /*
3900          * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
3901          * For buffered writes, at writepage time, etc.  Convert a
3902          * discovered unwritten extent to written.
3903          */
3904         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
3905         if (ret < 0) {
3906                 err = ret;
3907                 goto out2;
3908         }
3909         ext4_update_inode_fsync_trans(handle, inode, 1);
3910         /*
3911          * shouldn't get a 0 return when converting an unwritten extent
3912          * unless m_len is 0 (bug) or extent has been corrupted
3913          */
3914         if (unlikely(ret == 0)) {
3915                 EXT4_ERROR_INODE(inode, "unexpected ret == 0, m_len = %u",
3916                                  map->m_len);
3917                 err = -EFSCORRUPTED;
3918                 goto out2;
3919         }
3920
3921 out:
3922         allocated = ret;
3923         map->m_flags |= EXT4_MAP_NEW;
3924 map_out:
3925         map->m_flags |= EXT4_MAP_MAPPED;
3926 out1:
3927         map->m_pblk = newblock;
3928         if (allocated > map->m_len)
3929                 allocated = map->m_len;
3930         map->m_len = allocated;
3931         ext4_ext_show_leaf(inode, path);
3932 out2:
3933         return err ? err : allocated;
3934 }
3935
3936 /*
3937  * get_implied_cluster_alloc - check to see if the requested
3938  * allocation (in the map structure) overlaps with a cluster already
3939  * allocated in an extent.
3940  *      @sb     The filesystem superblock structure
3941  *      @map    The requested lblk->pblk mapping
3942  *      @ex     The extent structure which might contain an implied
3943  *                      cluster allocation
3944  *
3945  * This function is called by ext4_ext_map_blocks() after we failed to
3946  * find blocks that were already in the inode's extent tree.  Hence,
3947  * we know that the beginning of the requested region cannot overlap
3948  * the extent from the inode's extent tree.  There are three cases we
3949  * want to catch.  The first is this case:
3950  *
3951  *               |--- cluster # N--|
3952  *    |--- extent ---|  |---- requested region ---|
3953  *                      |==========|
3954  *
3955  * The second case that we need to test for is this one:
3956  *
3957  *   |--------- cluster # N ----------------|
3958  *         |--- requested region --|   |------- extent ----|
3959  *         |=======================|
3960  *
3961  * The third case is when the requested region lies between two extents
3962  * within the same cluster:
3963  *          |------------- cluster # N-------------|
3964  * |----- ex -----|                  |---- ex_right ----|
3965  *                  |------ requested region ------|
3966  *                  |================|
3967  *
3968  * In each of the above cases, we need to set the map->m_pblk and
3969  * map->m_len so it corresponds to the return the extent labelled as
3970  * "|====|" from cluster #N, since it is already in use for data in
3971  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
3972  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
3973  * as a new "allocated" block region.  Otherwise, we will return 0 and
3974  * ext4_ext_map_blocks() will then allocate one or more new clusters
3975  * by calling ext4_mb_new_blocks().
3976  */
3977 static int get_implied_cluster_alloc(struct super_block *sb,
3978                                      struct ext4_map_blocks *map,
3979                                      struct ext4_extent *ex,
3980                                      struct ext4_ext_path *path)
3981 {
3982         struct ext4_sb_info *sbi = EXT4_SB(sb);
3983         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
3984         ext4_lblk_t ex_cluster_start, ex_cluster_end;
3985         ext4_lblk_t rr_cluster_start;
3986         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3987         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3988         unsigned short ee_len = ext4_ext_get_actual_len(ex);
3989
3990         /* The extent passed in that we are trying to match */
3991         ex_cluster_start = EXT4_B2C(sbi, ee_block);
3992         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
3993
3994         /* The requested region passed into ext4_map_blocks() */
3995         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
3996
3997         if ((rr_cluster_start == ex_cluster_end) ||
3998             (rr_cluster_start == ex_cluster_start)) {
3999                 if (rr_cluster_start == ex_cluster_end)
4000                         ee_start += ee_len - 1;
4001                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4002                 map->m_len = min(map->m_len,
4003                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4004                 /*
4005                  * Check for and handle this case:
4006                  *
4007                  *   |--------- cluster # N-------------|
4008                  *                     |------- extent ----|
4009                  *         |--- requested region ---|
4010                  *         |===========|
4011                  */
4012
4013                 if (map->m_lblk < ee_block)
4014                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4015
4016                 /*
4017                  * Check for the case where there is already another allocated
4018                  * block to the right of 'ex' but before the end of the cluster.
4019                  *
4020                  *          |------------- cluster # N-------------|
4021                  * |----- ex -----|                  |---- ex_right ----|
4022                  *                  |------ requested region ------|
4023                  *                  |================|
4024                  */
4025                 if (map->m_lblk > ee_block) {
4026                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4027                         map->m_len = min(map->m_len, next - map->m_lblk);
4028                 }
4029
4030                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4031                 return 1;
4032         }
4033
4034         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4035         return 0;
4036 }
4037
4038 /*
4039  * Determine hole length around the given logical block, first try to
4040  * locate and expand the hole from the given @path, and then adjust it
4041  * if it's partially or completely converted to delayed extents, insert
4042  * it into the extent cache tree if it's indeed a hole, finally return
4043  * the length of the determined extent.
4044  */
4045 static ext4_lblk_t ext4_ext_determine_insert_hole(struct inode *inode,
4046                                                   struct ext4_ext_path *path,
4047                                                   ext4_lblk_t lblk)
4048 {
4049         ext4_lblk_t hole_start, len;
4050         struct extent_status es;
4051
4052         hole_start = lblk;
4053         len = ext4_ext_find_hole(inode, path, &hole_start);
4054 again:
4055         ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
4056                                   hole_start + len - 1, &es);
4057         if (!es.es_len)
4058                 goto insert_hole;
4059
4060         /*
4061          * There's a delalloc extent in the hole, handle it if the delalloc
4062          * extent is in front of, behind and straddle the queried range.
4063          */
4064         if (lblk >= es.es_lblk + es.es_len) {
4065                 /*
4066                  * The delalloc extent is in front of the queried range,
4067                  * find again from the queried start block.
4068                  */
4069                 len -= lblk - hole_start;
4070                 hole_start = lblk;
4071                 goto again;
4072         } else if (in_range(lblk, es.es_lblk, es.es_len)) {
4073                 /*
4074                  * The delalloc extent containing lblk, it must have been
4075                  * added after ext4_map_blocks() checked the extent status
4076                  * tree, adjust the length to the delalloc extent's after
4077                  * lblk.
4078                  */
4079                 len = es.es_lblk + es.es_len - lblk;
4080                 return len;
4081         } else {
4082                 /*
4083                  * The delalloc extent is partially or completely behind
4084                  * the queried range, update hole length until the
4085                  * beginning of the delalloc extent.
4086                  */
4087                 len = min(es.es_lblk - hole_start, len);
4088         }
4089
4090 insert_hole:
4091         /* Put just found gap into cache to speed up subsequent requests */
4092         ext_debug(inode, " -> %u:%u\n", hole_start, len);
4093         ext4_es_insert_extent(inode, hole_start, len, ~0, EXTENT_STATUS_HOLE);
4094
4095         /* Update hole_len to reflect hole size after lblk */
4096         if (hole_start != lblk)
4097                 len -= lblk - hole_start;
4098
4099         return len;
4100 }
4101
4102 /*
4103  * Block allocation/map/preallocation routine for extents based files
4104  *
4105  *
4106  * Need to be called with
4107  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4108  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4109  *
4110  * return > 0, number of blocks already mapped/allocated
4111  *          if create == 0 and these are pre-allocated blocks
4112  *              buffer head is unmapped
4113  *          otherwise blocks are mapped
4114  *
4115  * return = 0, if plain look up failed (blocks have not been allocated)
4116  *          buffer head is unmapped
4117  *
4118  * return < 0, error case.
4119  */
4120 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4121                         struct ext4_map_blocks *map, int flags)
4122 {
4123         struct ext4_ext_path *path = NULL;
4124         struct ext4_extent newex, *ex, ex2;
4125         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4126         ext4_fsblk_t newblock = 0, pblk;
4127         int err = 0, depth, ret;
4128         unsigned int allocated = 0, offset = 0;
4129         unsigned int allocated_clusters = 0;
4130         struct ext4_allocation_request ar;
4131         ext4_lblk_t cluster_offset;
4132
4133         ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
4134         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4135
4136         /* find extent for this block */
4137         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4138         if (IS_ERR(path)) {
4139                 err = PTR_ERR(path);
4140                 path = NULL;
4141                 goto out;
4142         }
4143
4144         depth = ext_depth(inode);
4145
4146         /*
4147          * consistent leaf must not be empty;
4148          * this situation is possible, though, _during_ tree modification;
4149          * this is why assert can't be put in ext4_find_extent()
4150          */
4151         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4152                 EXT4_ERROR_INODE(inode, "bad extent address "
4153                                  "lblock: %lu, depth: %d pblock %lld",
4154                                  (unsigned long) map->m_lblk, depth,
4155                                  path[depth].p_block);
4156                 err = -EFSCORRUPTED;
4157                 goto out;
4158         }
4159
4160         ex = path[depth].p_ext;
4161         if (ex) {
4162                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4163                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4164                 unsigned short ee_len;
4165
4166
4167                 /*
4168                  * unwritten extents are treated as holes, except that
4169                  * we split out initialized portions during a write.
4170                  */
4171                 ee_len = ext4_ext_get_actual_len(ex);
4172
4173                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4174
4175                 /* if found extent covers block, simply return it */
4176                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4177                         newblock = map->m_lblk - ee_block + ee_start;
4178                         /* number of remaining blocks in the extent */
4179                         allocated = ee_len - (map->m_lblk - ee_block);
4180                         ext_debug(inode, "%u fit into %u:%d -> %llu\n",
4181                                   map->m_lblk, ee_block, ee_len, newblock);
4182
4183                         /*
4184                          * If the extent is initialized check whether the
4185                          * caller wants to convert it to unwritten.
4186                          */
4187                         if ((!ext4_ext_is_unwritten(ex)) &&
4188                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4189                                 err = convert_initialized_extent(handle,
4190                                         inode, map, &path, &allocated);
4191                                 goto out;
4192                         } else if (!ext4_ext_is_unwritten(ex)) {
4193                                 map->m_flags |= EXT4_MAP_MAPPED;
4194                                 map->m_pblk = newblock;
4195                                 if (allocated > map->m_len)
4196                                         allocated = map->m_len;
4197                                 map->m_len = allocated;
4198                                 ext4_ext_show_leaf(inode, path);
4199                                 goto out;
4200                         }
4201
4202                         ret = ext4_ext_handle_unwritten_extents(
4203                                 handle, inode, map, &path, flags,
4204                                 allocated, newblock);
4205                         if (ret < 0)
4206                                 err = ret;
4207                         else
4208                                 allocated = ret;
4209                         goto out;
4210                 }
4211         }
4212
4213         /*
4214          * requested block isn't allocated yet;
4215          * we couldn't try to create block if create flag is zero
4216          */
4217         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4218                 ext4_lblk_t len;
4219
4220                 len = ext4_ext_determine_insert_hole(inode, path, map->m_lblk);
4221
4222                 map->m_pblk = 0;
4223                 map->m_len = min_t(unsigned int, map->m_len, len);
4224                 goto out;
4225         }
4226
4227         /*
4228          * Okay, we need to do block allocation.
4229          */
4230         newex.ee_block = cpu_to_le32(map->m_lblk);
4231         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4232
4233         /*
4234          * If we are doing bigalloc, check to see if the extent returned
4235          * by ext4_find_extent() implies a cluster we can use.
4236          */
4237         if (cluster_offset && ex &&
4238             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4239                 ar.len = allocated = map->m_len;
4240                 newblock = map->m_pblk;
4241                 goto got_allocated_blocks;
4242         }
4243
4244         /* find neighbour allocated blocks */
4245         ar.lleft = map->m_lblk;
4246         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4247         if (err)
4248                 goto out;
4249         ar.lright = map->m_lblk;
4250         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4251         if (err < 0)
4252                 goto out;
4253
4254         /* Check if the extent after searching to the right implies a
4255          * cluster we can use. */
4256         if ((sbi->s_cluster_ratio > 1) && err &&
4257             get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
4258                 ar.len = allocated = map->m_len;
4259                 newblock = map->m_pblk;
4260                 goto got_allocated_blocks;
4261         }
4262
4263         /*
4264          * See if request is beyond maximum number of blocks we can have in
4265          * a single extent. For an initialized extent this limit is
4266          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4267          * EXT_UNWRITTEN_MAX_LEN.
4268          */
4269         if (map->m_len > EXT_INIT_MAX_LEN &&
4270             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4271                 map->m_len = EXT_INIT_MAX_LEN;
4272         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4273                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4274                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4275
4276         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4277         newex.ee_len = cpu_to_le16(map->m_len);
4278         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4279         if (err)
4280                 allocated = ext4_ext_get_actual_len(&newex);
4281         else
4282                 allocated = map->m_len;
4283
4284         /* allocate new block */
4285         ar.inode = inode;
4286         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4287         ar.logical = map->m_lblk;
4288         /*
4289          * We calculate the offset from the beginning of the cluster
4290          * for the logical block number, since when we allocate a
4291          * physical cluster, the physical block should start at the
4292          * same offset from the beginning of the cluster.  This is
4293          * needed so that future calls to get_implied_cluster_alloc()
4294          * work correctly.
4295          */
4296         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4297         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4298         ar.goal -= offset;
4299         ar.logical -= offset;
4300         if (S_ISREG(inode->i_mode))
4301                 ar.flags = EXT4_MB_HINT_DATA;
4302         else
4303                 /* disable in-core preallocation for non-regular files */
4304                 ar.flags = 0;
4305         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4306                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4307         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4308                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4309         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4310                 ar.flags |= EXT4_MB_USE_RESERVED;
4311         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4312         if (!newblock)
4313                 goto out;
4314         allocated_clusters = ar.len;
4315         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4316         ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
4317                   ar.goal, newblock, ar.len, allocated);
4318         if (ar.len > allocated)
4319                 ar.len = allocated;
4320
4321 got_allocated_blocks:
4322         /* try to insert new extent into found leaf and return */
4323         pblk = newblock + offset;
4324         ext4_ext_store_pblock(&newex, pblk);
4325         newex.ee_len = cpu_to_le16(ar.len);
4326         /* Mark unwritten */
4327         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4328                 ext4_ext_mark_unwritten(&newex);
4329                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4330         }
4331
4332         err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags);
4333         if (err) {
4334                 if (allocated_clusters) {
4335                         int fb_flags = 0;
4336
4337                         /*
4338                          * free data blocks we just allocated.
4339                          * not a good idea to call discard here directly,
4340                          * but otherwise we'd need to call it every free().
4341                          */
4342                         ext4_discard_preallocations(inode, 0);
4343                         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4344                                 fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
4345                         ext4_free_blocks(handle, inode, NULL, newblock,
4346                                          EXT4_C2B(sbi, allocated_clusters),
4347                                          fb_flags);
4348                 }
4349                 goto out;
4350         }
4351
4352         /*
4353          * Reduce the reserved cluster count to reflect successful deferred
4354          * allocation of delayed allocated clusters or direct allocation of
4355          * clusters discovered to be delayed allocated.  Once allocated, a
4356          * cluster is not included in the reserved count.
4357          */
4358         if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
4359                 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4360                         /*
4361                          * When allocating delayed allocated clusters, simply
4362                          * reduce the reserved cluster count and claim quota
4363                          */
4364                         ext4_da_update_reserve_space(inode, allocated_clusters,
4365                                                         1);
4366                 } else {
4367                         ext4_lblk_t lblk, len;
4368                         unsigned int n;
4369
4370                         /*
4371                          * When allocating non-delayed allocated clusters
4372                          * (from fallocate, filemap, DIO, or clusters
4373                          * allocated when delalloc has been disabled by
4374                          * ext4_nonda_switch), reduce the reserved cluster
4375                          * count by the number of allocated clusters that
4376                          * have previously been delayed allocated.  Quota
4377                          * has been claimed by ext4_mb_new_blocks() above,
4378                          * so release the quota reservations made for any
4379                          * previously delayed allocated clusters.
4380                          */
4381                         lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4382                         len = allocated_clusters << sbi->s_cluster_bits;
4383                         n = ext4_es_delayed_clu(inode, lblk, len);
4384                         if (n > 0)
4385                                 ext4_da_update_reserve_space(inode, (int) n, 0);
4386                 }
4387         }
4388
4389         /*
4390          * Cache the extent and update transaction to commit on fdatasync only
4391          * when it is _not_ an unwritten extent.
4392          */
4393         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4394                 ext4_update_inode_fsync_trans(handle, inode, 1);
4395         else
4396                 ext4_update_inode_fsync_trans(handle, inode, 0);
4397
4398         map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
4399         map->m_pblk = pblk;
4400         map->m_len = ar.len;
4401         allocated = map->m_len;
4402         ext4_ext_show_leaf(inode, path);
4403 out:
4404         ext4_ext_drop_refs(path);
4405         kfree(path);
4406
4407         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4408                                        err ? err : allocated);
4409         return err ? err : allocated;
4410 }
4411
4412 int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4413 {
4414         struct super_block *sb = inode->i_sb;
4415         ext4_lblk_t last_block;
4416         int err = 0;
4417
4418         /*
4419          * TODO: optimization is possible here.
4420          * Probably we need not scan at all,
4421          * because page truncation is enough.
4422          */
4423
4424         /* we have to know where to truncate from in crash case */
4425         EXT4_I(inode)->i_disksize = inode->i_size;
4426         err = ext4_mark_inode_dirty(handle, inode);
4427         if (err)
4428                 return err;
4429
4430         last_block = (inode->i_size + sb->s_blocksize - 1)
4431                         >> EXT4_BLOCK_SIZE_BITS(sb);
4432 retry:
4433         err = ext4_es_remove_extent(inode, last_block,
4434                                     EXT_MAX_BLOCKS - last_block);
4435         if (err == -ENOMEM) {
4436                 cond_resched();
4437                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4438                 goto retry;
4439         }
4440         if (err)
4441                 return err;
4442 retry_remove_space:
4443         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4444         if (err == -ENOMEM) {
4445                 cond_resched();
4446                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4447                 goto retry_remove_space;
4448         }
4449         return err;
4450 }
4451
4452 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4453                                   ext4_lblk_t len, loff_t new_size,
4454                                   int flags)
4455 {
4456         struct inode *inode = file_inode(file);
4457         handle_t *handle;
4458         int ret = 0;
4459         int ret2 = 0, ret3 = 0;
4460         int retries = 0;
4461         int depth = 0;
4462         struct ext4_map_blocks map;
4463         unsigned int credits;
4464         loff_t epos;
4465
4466         BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4467         map.m_lblk = offset;
4468         map.m_len = len;
4469         /*
4470          * Don't normalize the request if it can fit in one extent so
4471          * that it doesn't get unnecessarily split into multiple
4472          * extents.
4473          */
4474         if (len <= EXT_UNWRITTEN_MAX_LEN)
4475                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4476
4477         /*
4478          * credits to insert 1 extent into extent tree
4479          */
4480         credits = ext4_chunk_trans_blocks(inode, len);
4481         depth = ext_depth(inode);
4482
4483 retry:
4484         while (ret >= 0 && len) {
4485                 /*
4486                  * Recalculate credits when extent tree depth changes.
4487                  */
4488                 if (depth != ext_depth(inode)) {
4489                         credits = ext4_chunk_trans_blocks(inode, len);
4490                         depth = ext_depth(inode);
4491                 }
4492
4493                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4494                                             credits);
4495                 if (IS_ERR(handle)) {
4496                         ret = PTR_ERR(handle);
4497                         break;
4498                 }
4499                 ret = ext4_map_blocks(handle, inode, &map, flags);
4500                 if (ret <= 0) {
4501                         ext4_debug("inode #%lu: block %u: len %u: "
4502                                    "ext4_ext_map_blocks returned %d",
4503                                    inode->i_ino, map.m_lblk,
4504                                    map.m_len, ret);
4505                         ext4_mark_inode_dirty(handle, inode);
4506                         ret2 = ext4_journal_stop(handle);
4507                         break;
4508                 }
4509                 map.m_lblk += ret;
4510                 map.m_len = len = len - ret;
4511                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4512                 inode->i_ctime = current_time(inode);
4513                 if (new_size) {
4514                         if (epos > new_size)
4515                                 epos = new_size;
4516                         if (ext4_update_inode_size(inode, epos) & 0x1)
4517                                 inode->i_mtime = inode->i_ctime;
4518                 }
4519                 ret2 = ext4_mark_inode_dirty(handle, inode);
4520                 ext4_update_inode_fsync_trans(handle, inode, 1);
4521                 ret3 = ext4_journal_stop(handle);
4522                 ret2 = ret3 ? ret3 : ret2;
4523                 if (unlikely(ret2))
4524                         break;
4525         }
4526         if (ret == -ENOSPC &&
4527                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4528                 ret = 0;
4529                 goto retry;
4530         }
4531
4532         return ret > 0 ? ret2 : ret;
4533 }
4534
4535 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);
4536
4537 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
4538
4539 static long ext4_zero_range(struct file *file, loff_t offset,
4540                             loff_t len, int mode)
4541 {
4542         struct inode *inode = file_inode(file);
4543         handle_t *handle = NULL;
4544         unsigned int max_blocks;
4545         loff_t new_size = 0;
4546         int ret = 0;
4547         int flags;
4548         int credits;
4549         int partial_begin, partial_end;
4550         loff_t start, end;
4551         ext4_lblk_t lblk;
4552         unsigned int blkbits = inode->i_blkbits;
4553
4554         trace_ext4_zero_range(inode, offset, len, mode);
4555
4556         /* Call ext4_force_commit to flush all data in case of data=journal. */
4557         if (ext4_should_journal_data(inode)) {
4558                 ret = ext4_force_commit(inode->i_sb);
4559                 if (ret)
4560                         return ret;
4561         }
4562
4563         /*
4564          * Round up offset. This is not fallocate, we need to zero out
4565          * blocks, so convert interior block aligned part of the range to
4566          * unwritten and possibly manually zero out unaligned parts of the
4567          * range.
4568          */
4569         start = round_up(offset, 1 << blkbits);
4570         end = round_down((offset + len), 1 << blkbits);
4571
4572         if (start < offset || end > offset + len)
4573                 return -EINVAL;
4574         partial_begin = offset & ((1 << blkbits) - 1);
4575         partial_end = (offset + len) & ((1 << blkbits) - 1);
4576
4577         lblk = start >> blkbits;
4578         max_blocks = (end >> blkbits);
4579         if (max_blocks < lblk)
4580                 max_blocks = 0;
4581         else
4582                 max_blocks -= lblk;
4583
4584         inode_lock(inode);
4585
4586         /*
4587          * Indirect files do not support unwritten extents
4588          */
4589         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4590                 ret = -EOPNOTSUPP;
4591                 goto out_mutex;
4592         }
4593
4594         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4595             (offset + len > inode->i_size ||
4596              offset + len > EXT4_I(inode)->i_disksize)) {
4597                 new_size = offset + len;
4598                 ret = inode_newsize_ok(inode, new_size);
4599                 if (ret)
4600                         goto out_mutex;
4601         }
4602
4603         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4604
4605         /* Wait all existing dio workers, newcomers will block on i_mutex */
4606         inode_dio_wait(inode);
4607
4608         ret = file_modified(file);
4609         if (ret)
4610                 goto out_mutex;
4611
4612         /* Preallocate the range including the unaligned edges */
4613         if (partial_begin || partial_end) {
4614                 ret = ext4_alloc_file_blocks(file,
4615                                 round_down(offset, 1 << blkbits) >> blkbits,
4616                                 (round_up((offset + len), 1 << blkbits) -
4617                                  round_down(offset, 1 << blkbits)) >> blkbits,
4618                                 new_size, flags);
4619                 if (ret)
4620                         goto out_mutex;
4621
4622         }
4623
4624         /* Zero range excluding the unaligned edges */
4625         if (max_blocks > 0) {
4626                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4627                           EXT4_EX_NOCACHE);
4628
4629                 /*
4630                  * Prevent page faults from reinstantiating pages we have
4631                  * released from page cache.
4632                  */
4633                 down_write(&EXT4_I(inode)->i_mmap_sem);
4634
4635                 ret = ext4_break_layouts(inode);
4636                 if (ret) {
4637                         up_write(&EXT4_I(inode)->i_mmap_sem);
4638                         goto out_mutex;
4639                 }
4640
4641                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4642                 if (ret) {
4643                         up_write(&EXT4_I(inode)->i_mmap_sem);
4644                         goto out_mutex;
4645                 }
4646                 /* Now release the pages and zero block aligned part of pages */
4647                 truncate_pagecache_range(inode, start, end - 1);
4648                 inode->i_mtime = inode->i_ctime = current_time(inode);
4649
4650                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4651                                              flags);
4652                 up_write(&EXT4_I(inode)->i_mmap_sem);
4653                 if (ret)
4654                         goto out_mutex;
4655         }
4656         if (!partial_begin && !partial_end)
4657                 goto out_mutex;
4658
4659         /*
4660          * In worst case we have to writeout two nonadjacent unwritten
4661          * blocks and update the inode
4662          */
4663         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4664         if (ext4_should_journal_data(inode))
4665                 credits += 2;
4666         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4667         if (IS_ERR(handle)) {
4668                 ret = PTR_ERR(handle);
4669                 ext4_std_error(inode->i_sb, ret);
4670                 goto out_mutex;
4671         }
4672
4673         inode->i_mtime = inode->i_ctime = current_time(inode);
4674         if (new_size)
4675                 ext4_update_inode_size(inode, new_size);
4676         ret = ext4_mark_inode_dirty(handle, inode);
4677         if (unlikely(ret))
4678                 goto out_handle;
4679         /* Zero out partial block at the edges of the range */
4680         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4681         if (ret >= 0)
4682                 ext4_update_inode_fsync_trans(handle, inode, 1);
4683
4684         if (file->f_flags & O_SYNC)
4685                 ext4_handle_sync(handle);
4686
4687 out_handle:
4688         ext4_journal_stop(handle);
4689 out_mutex:
4690         inode_unlock(inode);
4691         return ret;
4692 }
4693
4694 /*
4695  * preallocate space for a file. This implements ext4's fallocate file
4696  * operation, which gets called from sys_fallocate system call.
4697  * For block-mapped files, posix_fallocate should fall back to the method
4698  * of writing zeroes to the required new blocks (the same behavior which is
4699  * expected for file systems which do not support fallocate() system call).
4700  */
4701 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4702 {
4703         struct inode *inode = file_inode(file);
4704         loff_t new_size = 0;
4705         unsigned int max_blocks;
4706         int ret = 0;
4707         int flags;
4708         ext4_lblk_t lblk;
4709         unsigned int blkbits = inode->i_blkbits;
4710
4711         /*
4712          * Encrypted inodes can't handle collapse range or insert
4713          * range since we would need to re-encrypt blocks with a
4714          * different IV or XTS tweak (which are based on the logical
4715          * block number).
4716          */
4717         if (IS_ENCRYPTED(inode) &&
4718             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
4719                 return -EOPNOTSUPP;
4720
4721         /* Return error if mode is not supported */
4722         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4723                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4724                      FALLOC_FL_INSERT_RANGE))
4725                 return -EOPNOTSUPP;
4726
4727         inode_lock(inode);
4728         ret = ext4_convert_inline_data(inode);
4729         inode_unlock(inode);
4730         if (ret)
4731                 goto exit;
4732
4733         if (mode & FALLOC_FL_PUNCH_HOLE) {
4734                 ret = ext4_punch_hole(file, offset, len);
4735                 goto exit;
4736         }
4737
4738         if (mode & FALLOC_FL_COLLAPSE_RANGE) {
4739                 ret = ext4_collapse_range(file, offset, len);
4740                 goto exit;
4741         }
4742
4743         if (mode & FALLOC_FL_INSERT_RANGE) {
4744                 ret = ext4_insert_range(file, offset, len);
4745                 goto exit;
4746         }
4747
4748         if (mode & FALLOC_FL_ZERO_RANGE) {
4749                 ret = ext4_zero_range(file, offset, len, mode);
4750                 goto exit;
4751         }
4752         trace_ext4_fallocate_enter(inode, offset, len, mode);
4753         lblk = offset >> blkbits;
4754
4755         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4756         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4757
4758         inode_lock(inode);
4759
4760         /*
4761          * We only support preallocation for extent-based files only
4762          */
4763         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4764                 ret = -EOPNOTSUPP;
4765                 goto out;
4766         }
4767
4768         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4769             (offset + len > inode->i_size ||
4770              offset + len > EXT4_I(inode)->i_disksize)) {
4771                 new_size = offset + len;
4772                 ret = inode_newsize_ok(inode, new_size);
4773                 if (ret)
4774                         goto out;
4775         }
4776
4777         /* Wait all existing dio workers, newcomers will block on i_mutex */
4778         inode_dio_wait(inode);
4779
4780         ret = file_modified(file);
4781         if (ret)
4782                 goto out;
4783
4784         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4785         if (ret)
4786                 goto out;
4787
4788         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4789                 ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
4790                                         EXT4_I(inode)->i_sync_tid);
4791         }
4792 out:
4793         inode_unlock(inode);
4794         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4795 exit:
4796         return ret;
4797 }
4798
4799 /*
4800  * This function convert a range of blocks to written extents
4801  * The caller of this function will pass the start offset and the size.
4802  * all unwritten extents within this range will be converted to
4803  * written extents.
4804  *
4805  * This function is called from the direct IO end io call back
4806  * function, to convert the fallocated extents after IO is completed.
4807  * Returns 0 on success.
4808  */
4809 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4810                                    loff_t offset, ssize_t len)
4811 {
4812         unsigned int max_blocks;
4813         int ret = 0, ret2 = 0, ret3 = 0;
4814         struct ext4_map_blocks map;
4815         unsigned int blkbits = inode->i_blkbits;
4816         unsigned int credits = 0;
4817
4818         map.m_lblk = offset >> blkbits;
4819         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4820
4821         if (!handle) {
4822                 /*
4823                  * credits to insert 1 extent into extent tree
4824                  */
4825                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4826         }
4827         while (ret >= 0 && ret < max_blocks) {
4828                 map.m_lblk += ret;
4829                 map.m_len = (max_blocks -= ret);
4830                 if (credits) {
4831                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4832                                                     credits);
4833                         if (IS_ERR(handle)) {
4834                                 ret = PTR_ERR(handle);
4835                                 break;
4836                         }
4837                 }
4838                 ret = ext4_map_blocks(handle, inode, &map,
4839                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4840                 if (ret <= 0)
4841                         ext4_warning(inode->i_sb,
4842                                      "inode #%lu: block %u: len %u: "
4843                                      "ext4_ext_map_blocks returned %d",
4844                                      inode->i_ino, map.m_lblk,
4845                                      map.m_len, ret);
4846                 ret2 = ext4_mark_inode_dirty(handle, inode);
4847                 if (credits) {
4848                         ret3 = ext4_journal_stop(handle);
4849                         if (unlikely(ret3))
4850                                 ret2 = ret3;
4851                 }
4852
4853                 if (ret <= 0 || ret2)
4854                         break;
4855         }
4856         return ret > 0 ? ret2 : ret;
4857 }
4858
4859 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
4860 {
4861         int ret = 0, err = 0;
4862         struct ext4_io_end_vec *io_end_vec;
4863
4864         /*
4865          * This is somewhat ugly but the idea is clear: When transaction is
4866          * reserved, everything goes into it. Otherwise we rather start several
4867          * smaller transactions for conversion of each extent separately.
4868          */
4869         if (handle) {
4870                 handle = ext4_journal_start_reserved(handle,
4871                                                      EXT4_HT_EXT_CONVERT);
4872                 if (IS_ERR(handle))
4873                         return PTR_ERR(handle);
4874         }
4875
4876         list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4877                 ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4878                                                      io_end_vec->offset,
4879                                                      io_end_vec->size);
4880                 if (ret)
4881                         break;
4882         }
4883
4884         if (handle)
4885                 err = ext4_journal_stop(handle);
4886
4887         return ret < 0 ? ret : err;
4888 }
4889
4890 static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
4891 {
4892         __u64 physical = 0;
4893         __u64 length = 0;
4894         int blockbits = inode->i_sb->s_blocksize_bits;
4895         int error = 0;
4896         u16 iomap_type;
4897
4898         /* in-inode? */
4899         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4900                 struct ext4_iloc iloc;
4901                 int offset;     /* offset of xattr in inode */
4902
4903                 error = ext4_get_inode_loc(inode, &iloc);
4904                 if (error)
4905                         return error;
4906                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
4907                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4908                                 EXT4_I(inode)->i_extra_isize;
4909                 physical += offset;
4910                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4911                 brelse(iloc.bh);
4912                 iomap_type = IOMAP_INLINE;
4913         } else if (EXT4_I(inode)->i_file_acl) { /* external block */
4914                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4915                 length = inode->i_sb->s_blocksize;
4916                 iomap_type = IOMAP_MAPPED;
4917         } else {
4918                 /* no in-inode or external block for xattr, so return -ENOENT */
4919                 error = -ENOENT;
4920                 goto out;
4921         }
4922
4923         iomap->addr = physical;
4924         iomap->offset = 0;
4925         iomap->length = length;
4926         iomap->type = iomap_type;
4927         iomap->flags = 0;
4928 out:
4929         return error;
4930 }
4931
4932 static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
4933                                   loff_t length, unsigned flags,
4934                                   struct iomap *iomap, struct iomap *srcmap)
4935 {
4936         int error;
4937
4938         error = ext4_iomap_xattr_fiemap(inode, iomap);
4939         if (error == 0 && (offset >= iomap->length))
4940                 error = -ENOENT;
4941         return error;
4942 }
4943
4944 static const struct iomap_ops ext4_iomap_xattr_ops = {
4945         .iomap_begin            = ext4_iomap_xattr_begin,
4946 };
4947
4948 static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
4949 {
4950         u64 maxbytes;
4951
4952         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4953                 maxbytes = inode->i_sb->s_maxbytes;
4954         else
4955                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
4956
4957         if (*len == 0)
4958                 return -EINVAL;
4959         if (start > maxbytes)
4960                 return -EFBIG;
4961
4962         /*
4963          * Shrink request scope to what the fs can actually handle.
4964          */
4965         if (*len > maxbytes || (maxbytes - *len) < start)
4966                 *len = maxbytes - start;
4967         return 0;
4968 }
4969
4970 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4971                 u64 start, u64 len)
4972 {
4973         int error = 0;
4974
4975         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4976                 error = ext4_ext_precache(inode);
4977                 if (error)
4978                         return error;
4979                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4980         }
4981
4982         /*
4983          * For bitmap files the maximum size limit could be smaller than
4984          * s_maxbytes, so check len here manually instead of just relying on the
4985          * generic check.
4986          */
4987         error = ext4_fiemap_check_ranges(inode, start, &len);
4988         if (error)
4989                 return error;
4990
4991         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4992                 fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
4993                 return iomap_fiemap(inode, fieinfo, start, len,
4994                                     &ext4_iomap_xattr_ops);
4995         }
4996
4997         return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
4998 }
4999
5000 int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
5001                       __u64 start, __u64 len)
5002 {
5003         ext4_lblk_t start_blk, len_blks;
5004         __u64 last_blk;
5005         int error = 0;
5006
5007         if (ext4_has_inline_data(inode)) {
5008                 int has_inline;
5009
5010                 down_read(&EXT4_I(inode)->xattr_sem);
5011                 has_inline = ext4_has_inline_data(inode);
5012                 up_read(&EXT4_I(inode)->xattr_sem);
5013                 if (has_inline)
5014                         return 0;
5015         }
5016
5017         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5018                 error = ext4_ext_precache(inode);
5019                 if (error)
5020                         return error;
5021                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
5022         }
5023
5024         error = fiemap_prep(inode, fieinfo, start, &len, 0);
5025         if (error)
5026                 return error;
5027
5028         error = ext4_fiemap_check_ranges(inode, start, &len);
5029         if (error)
5030                 return error;
5031
5032         start_blk = start >> inode->i_sb->s_blocksize_bits;
5033         last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5034         if (last_blk >= EXT_MAX_BLOCKS)
5035                 last_blk = EXT_MAX_BLOCKS-1;
5036         len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5037
5038         /*
5039          * Walk the extent tree gathering extent information
5040          * and pushing extents back to the user.
5041          */
5042         return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
5043 }
5044
5045 /*
5046  * ext4_ext_shift_path_extents:
5047  * Shift the extents of a path structure lying between path[depth].p_ext
5048  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5049  * if it is right shift or left shift operation.
5050  */
5051 static int
5052 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5053                             struct inode *inode, handle_t *handle,
5054                             enum SHIFT_DIRECTION SHIFT)
5055 {
5056         int depth, err = 0;
5057         struct ext4_extent *ex_start, *ex_last;
5058         bool update = false;
5059         int credits, restart_credits;
5060         depth = path->p_depth;
5061
5062         while (depth >= 0) {
5063                 if (depth == path->p_depth) {
5064                         ex_start = path[depth].p_ext;
5065                         if (!ex_start)
5066                                 return -EFSCORRUPTED;
5067
5068                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5069                         /* leaf + sb + inode */
5070                         credits = 3;
5071                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
5072                                 update = true;
5073                                 /* extent tree + sb + inode */
5074                                 credits = depth + 2;
5075                         }
5076
5077                         restart_credits = ext4_writepage_trans_blocks(inode);
5078                         err = ext4_datasem_ensure_credits(handle, inode, credits,
5079                                         restart_credits, 0);
5080                         if (err) {
5081                                 if (err > 0)
5082                                         err = -EAGAIN;
5083                                 goto out;
5084                         }
5085
5086                         err = ext4_ext_get_access(handle, inode, path + depth);
5087                         if (err)
5088                                 goto out;
5089
5090                         while (ex_start <= ex_last) {
5091                                 if (SHIFT == SHIFT_LEFT) {
5092                                         le32_add_cpu(&ex_start->ee_block,
5093                                                 -shift);
5094                                         /* Try to merge to the left. */
5095                                         if ((ex_start >
5096                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5097                                             &&
5098                                             ext4_ext_try_to_merge_right(inode,
5099                                             path, ex_start - 1))
5100                                                 ex_last--;
5101                                         else
5102                                                 ex_start++;
5103                                 } else {
5104                                         le32_add_cpu(&ex_last->ee_block, shift);
5105                                         ext4_ext_try_to_merge_right(inode, path,
5106                                                 ex_last);
5107                                         ex_last--;
5108                                 }
5109                         }
5110                         err = ext4_ext_dirty(handle, inode, path + depth);
5111                         if (err)
5112                                 goto out;
5113
5114                         if (--depth < 0 || !update)
5115                                 break;
5116                 }
5117
5118                 /* Update index too */
5119                 err = ext4_ext_get_access(handle, inode, path + depth);
5120                 if (err)
5121                         goto out;
5122
5123                 if (SHIFT == SHIFT_LEFT)
5124                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5125                 else
5126                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5127                 err = ext4_ext_dirty(handle, inode, path + depth);
5128                 if (err)
5129                         goto out;
5130
5131                 /* we are done if current index is not a starting index */
5132                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5133                         break;
5134
5135                 depth--;
5136         }
5137
5138 out:
5139         return err;
5140 }
5141
5142 /*
5143  * ext4_ext_shift_extents:
5144  * All the extents which lies in the range from @start to the last allocated
5145  * block for the @inode are shifted either towards left or right (depending
5146  * upon @SHIFT) by @shift blocks.
5147  * On success, 0 is returned, error otherwise.
5148  */
5149 static int
5150 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5151                        ext4_lblk_t start, ext4_lblk_t shift,
5152                        enum SHIFT_DIRECTION SHIFT)
5153 {
5154         struct ext4_ext_path *path;
5155         int ret = 0, depth;
5156         struct ext4_extent *extent;
5157         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5158         ext4_lblk_t tmp = EXT_MAX_BLOCKS;
5159
5160         /* Let path point to the last extent */
5161         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5162                                 EXT4_EX_NOCACHE);
5163         if (IS_ERR(path))
5164                 return PTR_ERR(path);
5165
5166         depth = path->p_depth;
5167         extent = path[depth].p_ext;
5168         if (!extent)
5169                 goto out;
5170
5171         stop = le32_to_cpu(extent->ee_block);
5172
5173        /*
5174         * For left shifts, make sure the hole on the left is big enough to
5175         * accommodate the shift.  For right shifts, make sure the last extent
5176         * won't be shifted beyond EXT_MAX_BLOCKS.
5177         */
5178         if (SHIFT == SHIFT_LEFT) {
5179                 path = ext4_find_extent(inode, start - 1, &path,
5180                                         EXT4_EX_NOCACHE);
5181                 if (IS_ERR(path))
5182                         return PTR_ERR(path);
5183                 depth = path->p_depth;
5184                 extent =  path[depth].p_ext;
5185                 if (extent) {
5186                         ex_start = le32_to_cpu(extent->ee_block);
5187                         ex_end = le32_to_cpu(extent->ee_block) +
5188                                 ext4_ext_get_actual_len(extent);
5189                 } else {
5190                         ex_start = 0;
5191                         ex_end = 0;
5192                 }
5193
5194                 if ((start == ex_start && shift > ex_start) ||
5195                     (shift > start - ex_end)) {
5196                         ret = -EINVAL;
5197                         goto out;
5198                 }
5199         } else {
5200                 if (shift > EXT_MAX_BLOCKS -
5201                     (stop + ext4_ext_get_actual_len(extent))) {
5202                         ret = -EINVAL;
5203                         goto out;
5204                 }
5205         }
5206
5207         /*
5208          * In case of left shift, iterator points to start and it is increased
5209          * till we reach stop. In case of right shift, iterator points to stop
5210          * and it is decreased till we reach start.
5211          */
5212 again:
5213         ret = 0;
5214         if (SHIFT == SHIFT_LEFT)
5215                 iterator = &start;
5216         else
5217                 iterator = &stop;
5218
5219         if (tmp != EXT_MAX_BLOCKS)
5220                 *iterator = tmp;
5221
5222         /*
5223          * Its safe to start updating extents.  Start and stop are unsigned, so
5224          * in case of right shift if extent with 0 block is reached, iterator
5225          * becomes NULL to indicate the end of the loop.
5226          */
5227         while (iterator && start <= stop) {
5228                 path = ext4_find_extent(inode, *iterator, &path,
5229                                         EXT4_EX_NOCACHE);
5230                 if (IS_ERR(path))
5231                         return PTR_ERR(path);
5232                 depth = path->p_depth;
5233                 extent = path[depth].p_ext;
5234                 if (!extent) {
5235                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5236                                          (unsigned long) *iterator);
5237                         return -EFSCORRUPTED;
5238                 }
5239                 if (SHIFT == SHIFT_LEFT && *iterator >
5240                     le32_to_cpu(extent->ee_block)) {
5241                         /* Hole, move to the next extent */
5242                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5243                                 path[depth].p_ext++;
5244                         } else {
5245                                 *iterator = ext4_ext_next_allocated_block(path);
5246                                 continue;
5247                         }
5248                 }
5249
5250                 tmp = *iterator;
5251                 if (SHIFT == SHIFT_LEFT) {
5252                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5253                         *iterator = le32_to_cpu(extent->ee_block) +
5254                                         ext4_ext_get_actual_len(extent);
5255                 } else {
5256                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5257                         if (le32_to_cpu(extent->ee_block) > start)
5258                                 *iterator = le32_to_cpu(extent->ee_block) - 1;
5259                         else if (le32_to_cpu(extent->ee_block) == start)
5260                                 iterator = NULL;
5261                         else {
5262                                 extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5263                                 while (le32_to_cpu(extent->ee_block) >= start)
5264                                         extent--;
5265
5266                                 if (extent == EXT_LAST_EXTENT(path[depth].p_hdr))
5267                                         break;
5268
5269                                 extent++;
5270                                 iterator = NULL;
5271                         }
5272                         path[depth].p_ext = extent;
5273                 }
5274                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5275                                 handle, SHIFT);
5276                 /* iterator can be NULL which means we should break */
5277                 if (ret == -EAGAIN)
5278                         goto again;
5279                 if (ret)
5280                         break;
5281         }
5282 out:
5283         ext4_ext_drop_refs(path);
5284         kfree(path);
5285         return ret;
5286 }
5287
5288 /*
5289  * ext4_collapse_range:
5290  * This implements the fallocate's collapse range functionality for ext4
5291  * Returns: 0 and non-zero on error.
5292  */
5293 static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)
5294 {
5295         struct inode *inode = file_inode(file);
5296         struct super_block *sb = inode->i_sb;
5297         ext4_lblk_t punch_start, punch_stop;
5298         handle_t *handle;
5299         unsigned int credits;
5300         loff_t new_size, ioffset;
5301         int ret;
5302
5303         /*
5304          * We need to test this early because xfstests assumes that a
5305          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5306          * system does not support collapse range.
5307          */
5308         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5309                 return -EOPNOTSUPP;
5310
5311         /* Collapse range works only on fs cluster size aligned regions. */
5312         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5313                 return -EINVAL;
5314
5315         trace_ext4_collapse_range(inode, offset, len);
5316
5317         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5318         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5319
5320         /* Call ext4_force_commit to flush all data in case of data=journal. */
5321         if (ext4_should_journal_data(inode)) {
5322                 ret = ext4_force_commit(inode->i_sb);
5323                 if (ret)
5324                         return ret;
5325         }
5326
5327         inode_lock(inode);
5328         /*
5329          * There is no need to overlap collapse range with EOF, in which case
5330          * it is effectively a truncate operation
5331          */
5332         if (offset + len >= inode->i_size) {
5333                 ret = -EINVAL;
5334                 goto out_mutex;
5335         }
5336
5337         /* Currently just for extent based files */
5338         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5339                 ret = -EOPNOTSUPP;
5340                 goto out_mutex;
5341         }
5342
5343         /* Wait for existing dio to complete */
5344         inode_dio_wait(inode);
5345
5346         ret = file_modified(file);
5347         if (ret)
5348                 goto out_mutex;
5349
5350         /*
5351          * Prevent page faults from reinstantiating pages we have released from
5352          * page cache.
5353          */
5354         down_write(&EXT4_I(inode)->i_mmap_sem);
5355
5356         ret = ext4_break_layouts(inode);
5357         if (ret)
5358                 goto out_mmap;
5359
5360         /*
5361          * Need to round down offset to be aligned with page size boundary
5362          * for page size > block size.
5363          */
5364         ioffset = round_down(offset, PAGE_SIZE);
5365         /*
5366          * Write tail of the last page before removed range since it will get
5367          * removed from the page cache below.
5368          */
5369         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5370         if (ret)
5371                 goto out_mmap;
5372         /*
5373          * Write data that will be shifted to preserve them when discarding
5374          * page cache below. We are also protected from pages becoming dirty
5375          * by i_mmap_sem.
5376          */
5377         ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5378                                            LLONG_MAX);
5379         if (ret)
5380                 goto out_mmap;
5381         truncate_pagecache(inode, ioffset);
5382
5383         credits = ext4_writepage_trans_blocks(inode);
5384         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5385         if (IS_ERR(handle)) {
5386                 ret = PTR_ERR(handle);
5387                 goto out_mmap;
5388         }
5389         ext4_fc_start_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE);
5390
5391         down_write(&EXT4_I(inode)->i_data_sem);
5392         ext4_discard_preallocations(inode, 0);
5393
5394         ret = ext4_es_remove_extent(inode, punch_start,
5395                                     EXT_MAX_BLOCKS - punch_start);
5396         if (ret) {
5397                 up_write(&EXT4_I(inode)->i_data_sem);
5398                 goto out_stop;
5399         }
5400
5401         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5402         if (ret) {
5403                 up_write(&EXT4_I(inode)->i_data_sem);
5404                 goto out_stop;
5405         }
5406         ext4_discard_preallocations(inode, 0);
5407
5408         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5409                                      punch_stop - punch_start, SHIFT_LEFT);
5410         if (ret) {
5411                 up_write(&EXT4_I(inode)->i_data_sem);
5412                 goto out_stop;
5413         }
5414
5415         new_size = inode->i_size - len;
5416         i_size_write(inode, new_size);
5417         EXT4_I(inode)->i_disksize = new_size;
5418
5419         up_write(&EXT4_I(inode)->i_data_sem);
5420         if (IS_SYNC(inode))
5421                 ext4_handle_sync(handle);
5422         inode->i_mtime = inode->i_ctime = current_time(inode);
5423         ret = ext4_mark_inode_dirty(handle, inode);
5424         ext4_update_inode_fsync_trans(handle, inode, 1);
5425
5426 out_stop:
5427         ext4_journal_stop(handle);
5428         ext4_fc_stop_ineligible(sb);
5429 out_mmap:
5430         up_write(&EXT4_I(inode)->i_mmap_sem);
5431 out_mutex:
5432         inode_unlock(inode);
5433         return ret;
5434 }
5435
5436 /*
5437  * ext4_insert_range:
5438  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5439  * The data blocks starting from @offset to the EOF are shifted by @len
5440  * towards right to create a hole in the @inode. Inode size is increased
5441  * by len bytes.
5442  * Returns 0 on success, error otherwise.
5443  */
5444 static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
5445 {
5446         struct inode *inode = file_inode(file);
5447         struct super_block *sb = inode->i_sb;
5448         handle_t *handle;
5449         struct ext4_ext_path *path;
5450         struct ext4_extent *extent;
5451         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5452         unsigned int credits, ee_len;
5453         int ret = 0, depth, split_flag = 0;
5454         loff_t ioffset;
5455
5456         /*
5457          * We need to test this early because xfstests assumes that an
5458          * insert range of (0, 1) will return EOPNOTSUPP if the file
5459          * system does not support insert range.
5460          */
5461         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5462                 return -EOPNOTSUPP;
5463
5464         /* Insert range works only on fs cluster size aligned regions. */
5465         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5466                 return -EINVAL;
5467
5468         trace_ext4_insert_range(inode, offset, len);
5469
5470         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5471         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5472
5473         /* Call ext4_force_commit to flush all data in case of data=journal */
5474         if (ext4_should_journal_data(inode)) {
5475                 ret = ext4_force_commit(inode->i_sb);
5476                 if (ret)
5477                         return ret;
5478         }
5479
5480         inode_lock(inode);
5481         /* Currently just for extent based files */
5482         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5483                 ret = -EOPNOTSUPP;
5484                 goto out_mutex;
5485         }
5486
5487         /* Check whether the maximum file size would be exceeded */
5488         if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5489                 ret = -EFBIG;
5490                 goto out_mutex;
5491         }
5492
5493         /* Offset must be less than i_size */
5494         if (offset >= inode->i_size) {
5495                 ret = -EINVAL;
5496                 goto out_mutex;
5497         }
5498
5499         /* Wait for existing dio to complete */
5500         inode_dio_wait(inode);
5501
5502         ret = file_modified(file);
5503         if (ret)
5504                 goto out_mutex;
5505
5506         /*
5507          * Prevent page faults from reinstantiating pages we have released from
5508          * page cache.
5509          */
5510         down_write(&EXT4_I(inode)->i_mmap_sem);
5511
5512         ret = ext4_break_layouts(inode);
5513         if (ret)
5514                 goto out_mmap;
5515
5516         /*
5517          * Need to round down to align start offset to page size boundary
5518          * for page size > block size.
5519          */
5520         ioffset = round_down(offset, PAGE_SIZE);
5521         /* Write out all dirty pages */
5522         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5523                         LLONG_MAX);
5524         if (ret)
5525                 goto out_mmap;
5526         truncate_pagecache(inode, ioffset);
5527
5528         credits = ext4_writepage_trans_blocks(inode);
5529         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5530         if (IS_ERR(handle)) {
5531                 ret = PTR_ERR(handle);
5532                 goto out_mmap;
5533         }
5534         ext4_fc_start_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE);
5535
5536         /* Expand file to avoid data loss if there is error while shifting */
5537         inode->i_size += len;
5538         EXT4_I(inode)->i_disksize += len;
5539         inode->i_mtime = inode->i_ctime = current_time(inode);
5540         ret = ext4_mark_inode_dirty(handle, inode);
5541         if (ret)
5542                 goto out_stop;
5543
5544         down_write(&EXT4_I(inode)->i_data_sem);
5545         ext4_discard_preallocations(inode, 0);
5546
5547         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5548         if (IS_ERR(path)) {
5549                 up_write(&EXT4_I(inode)->i_data_sem);
5550                 goto out_stop;
5551         }
5552
5553         depth = ext_depth(inode);
5554         extent = path[depth].p_ext;
5555         if (extent) {
5556                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5557                 ee_len = ext4_ext_get_actual_len(extent);
5558
5559                 /*
5560                  * If offset_lblk is not the starting block of extent, split
5561                  * the extent @offset_lblk
5562                  */
5563                 if ((offset_lblk > ee_start_lblk) &&
5564                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5565                         if (ext4_ext_is_unwritten(extent))
5566                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5567                                         EXT4_EXT_MARK_UNWRIT2;
5568                         ret = ext4_split_extent_at(handle, inode, &path,
5569                                         offset_lblk, split_flag,
5570                                         EXT4_EX_NOCACHE |
5571                                         EXT4_GET_BLOCKS_PRE_IO |
5572                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5573                 }
5574
5575                 ext4_ext_drop_refs(path);
5576                 kfree(path);
5577                 if (ret < 0) {
5578                         up_write(&EXT4_I(inode)->i_data_sem);
5579                         goto out_stop;
5580                 }
5581         } else {
5582                 ext4_ext_drop_refs(path);
5583                 kfree(path);
5584         }
5585
5586         ret = ext4_es_remove_extent(inode, offset_lblk,
5587                         EXT_MAX_BLOCKS - offset_lblk);
5588         if (ret) {
5589                 up_write(&EXT4_I(inode)->i_data_sem);
5590                 goto out_stop;
5591         }
5592
5593         /*
5594          * if offset_lblk lies in a hole which is at start of file, use
5595          * ee_start_lblk to shift extents
5596          */
5597         ret = ext4_ext_shift_extents(inode, handle,
5598                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5599                 len_lblk, SHIFT_RIGHT);
5600
5601         up_write(&EXT4_I(inode)->i_data_sem);
5602         if (IS_SYNC(inode))
5603                 ext4_handle_sync(handle);
5604         if (ret >= 0)
5605                 ext4_update_inode_fsync_trans(handle, inode, 1);
5606
5607 out_stop:
5608         ext4_journal_stop(handle);
5609         ext4_fc_stop_ineligible(sb);
5610 out_mmap:
5611         up_write(&EXT4_I(inode)->i_mmap_sem);
5612 out_mutex:
5613         inode_unlock(inode);
5614         return ret;
5615 }
5616
5617 /**
5618  * ext4_swap_extents() - Swap extents between two inodes
5619  * @handle: handle for this transaction
5620  * @inode1:     First inode
5621  * @inode2:     Second inode
5622  * @lblk1:      Start block for first inode
5623  * @lblk2:      Start block for second inode
5624  * @count:      Number of blocks to swap
5625  * @unwritten: Mark second inode's extents as unwritten after swap
5626  * @erp:        Pointer to save error value
5627  *
5628  * This helper routine does exactly what is promise "swap extents". All other
5629  * stuff such as page-cache locking consistency, bh mapping consistency or
5630  * extent's data copying must be performed by caller.
5631  * Locking:
5632  *              i_mutex is held for both inodes
5633  *              i_data_sem is locked for write for both inodes
5634  * Assumptions:
5635  *              All pages from requested range are locked for both inodes
5636  */
5637 int
5638 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5639                   struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5640                   ext4_lblk_t count, int unwritten, int *erp)
5641 {
5642         struct ext4_ext_path *path1 = NULL;
5643         struct ext4_ext_path *path2 = NULL;
5644         int replaced_count = 0;
5645
5646         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5647         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5648         BUG_ON(!inode_is_locked(inode1));
5649         BUG_ON(!inode_is_locked(inode2));
5650
5651         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5652         if (unlikely(*erp))
5653                 return 0;
5654         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5655         if (unlikely(*erp))
5656                 return 0;
5657
5658         while (count) {
5659                 struct ext4_extent *ex1, *ex2, tmp_ex;
5660                 ext4_lblk_t e1_blk, e2_blk;
5661                 int e1_len, e2_len, len;
5662                 int split = 0;
5663
5664                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5665                 if (IS_ERR(path1)) {
5666                         *erp = PTR_ERR(path1);
5667                         path1 = NULL;
5668                 finish:
5669                         count = 0;
5670                         goto repeat;
5671                 }
5672                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5673                 if (IS_ERR(path2)) {
5674                         *erp = PTR_ERR(path2);
5675                         path2 = NULL;
5676                         goto finish;
5677                 }
5678                 ex1 = path1[path1->p_depth].p_ext;
5679                 ex2 = path2[path2->p_depth].p_ext;
5680                 /* Do we have something to swap ? */
5681                 if (unlikely(!ex2 || !ex1))
5682                         goto finish;
5683
5684                 e1_blk = le32_to_cpu(ex1->ee_block);
5685                 e2_blk = le32_to_cpu(ex2->ee_block);
5686                 e1_len = ext4_ext_get_actual_len(ex1);
5687                 e2_len = ext4_ext_get_actual_len(ex2);
5688
5689                 /* Hole handling */
5690                 if (!in_range(lblk1, e1_blk, e1_len) ||
5691                     !in_range(lblk2, e2_blk, e2_len)) {
5692                         ext4_lblk_t next1, next2;
5693
5694                         /* if hole after extent, then go to next extent */
5695                         next1 = ext4_ext_next_allocated_block(path1);
5696                         next2 = ext4_ext_next_allocated_block(path2);
5697                         /* If hole before extent, then shift to that extent */
5698                         if (e1_blk > lblk1)
5699                                 next1 = e1_blk;
5700                         if (e2_blk > lblk2)
5701                                 next2 = e2_blk;
5702                         /* Do we have something to swap */
5703                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5704                                 goto finish;
5705                         /* Move to the rightest boundary */
5706                         len = next1 - lblk1;
5707                         if (len < next2 - lblk2)
5708                                 len = next2 - lblk2;
5709                         if (len > count)
5710                                 len = count;
5711                         lblk1 += len;
5712                         lblk2 += len;
5713                         count -= len;
5714                         goto repeat;
5715                 }
5716
5717                 /* Prepare left boundary */
5718                 if (e1_blk < lblk1) {
5719                         split = 1;
5720                         *erp = ext4_force_split_extent_at(handle, inode1,
5721                                                 &path1, lblk1, 0);
5722                         if (unlikely(*erp))
5723                                 goto finish;
5724                 }
5725                 if (e2_blk < lblk2) {
5726                         split = 1;
5727                         *erp = ext4_force_split_extent_at(handle, inode2,
5728                                                 &path2,  lblk2, 0);
5729                         if (unlikely(*erp))
5730                                 goto finish;
5731                 }
5732                 /* ext4_split_extent_at() may result in leaf extent split,
5733                  * path must to be revalidated. */
5734                 if (split)
5735                         goto repeat;
5736
5737                 /* Prepare right boundary */
5738                 len = count;
5739                 if (len > e1_blk + e1_len - lblk1)
5740                         len = e1_blk + e1_len - lblk1;
5741                 if (len > e2_blk + e2_len - lblk2)
5742                         len = e2_blk + e2_len - lblk2;
5743
5744                 if (len != e1_len) {
5745                         split = 1;
5746                         *erp = ext4_force_split_extent_at(handle, inode1,
5747                                                 &path1, lblk1 + len, 0);
5748                         if (unlikely(*erp))
5749                                 goto finish;
5750                 }
5751                 if (len != e2_len) {
5752                         split = 1;
5753                         *erp = ext4_force_split_extent_at(handle, inode2,
5754                                                 &path2, lblk2 + len, 0);
5755                         if (*erp)
5756                                 goto finish;
5757                 }
5758                 /* ext4_split_extent_at() may result in leaf extent split,
5759                  * path must to be revalidated. */
5760                 if (split)
5761                         goto repeat;
5762
5763                 BUG_ON(e2_len != e1_len);
5764                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5765                 if (unlikely(*erp))
5766                         goto finish;
5767                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5768                 if (unlikely(*erp))
5769                         goto finish;
5770
5771                 /* Both extents are fully inside boundaries. Swap it now */
5772                 tmp_ex = *ex1;
5773                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5774                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5775                 ex1->ee_len = cpu_to_le16(e2_len);
5776                 ex2->ee_len = cpu_to_le16(e1_len);
5777                 if (unwritten)
5778                         ext4_ext_mark_unwritten(ex2);
5779                 if (ext4_ext_is_unwritten(&tmp_ex))
5780                         ext4_ext_mark_unwritten(ex1);
5781
5782                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5783                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5784                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5785                                       path2->p_depth);
5786                 if (unlikely(*erp))
5787                         goto finish;
5788                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5789                                       path1->p_depth);
5790                 /*
5791                  * Looks scarry ah..? second inode already points to new blocks,
5792                  * and it was successfully dirtied. But luckily error may happen
5793                  * only due to journal error, so full transaction will be
5794                  * aborted anyway.
5795                  */
5796                 if (unlikely(*erp))
5797                         goto finish;
5798                 lblk1 += len;
5799                 lblk2 += len;
5800                 replaced_count += len;
5801                 count -= len;
5802
5803         repeat:
5804                 ext4_ext_drop_refs(path1);
5805                 kfree(path1);
5806                 ext4_ext_drop_refs(path2);
5807                 kfree(path2);
5808                 path1 = path2 = NULL;
5809         }
5810         return replaced_count;
5811 }
5812
5813 /*
5814  * ext4_clu_mapped - determine whether any block in a logical cluster has
5815  *                   been mapped to a physical cluster
5816  *
5817  * @inode - file containing the logical cluster
5818  * @lclu - logical cluster of interest
5819  *
5820  * Returns 1 if any block in the logical cluster is mapped, signifying
5821  * that a physical cluster has been allocated for it.  Otherwise,
5822  * returns 0.  Can also return negative error codes.  Derived from
5823  * ext4_ext_map_blocks().
5824  */
5825 int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5826 {
5827         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5828         struct ext4_ext_path *path;
5829         int depth, mapped = 0, err = 0;
5830         struct ext4_extent *extent;
5831         ext4_lblk_t first_lblk, first_lclu, last_lclu;
5832
5833         /*
5834          * if data can be stored inline, the logical cluster isn't
5835          * mapped - no physical clusters have been allocated, and the
5836          * file has no extents
5837          */
5838         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) ||
5839             ext4_has_inline_data(inode))
5840                 return 0;
5841
5842         /* search for the extent closest to the first block in the cluster */
5843         path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5844         if (IS_ERR(path)) {
5845                 err = PTR_ERR(path);
5846                 path = NULL;
5847                 goto out;
5848         }
5849
5850         depth = ext_depth(inode);
5851
5852         /*
5853          * A consistent leaf must not be empty.  This situation is possible,
5854          * though, _during_ tree modification, and it's why an assert can't
5855          * be put in ext4_find_extent().
5856          */
5857         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5858                 EXT4_ERROR_INODE(inode,
5859                     "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5860                                  (unsigned long) EXT4_C2B(sbi, lclu),
5861                                  depth, path[depth].p_block);
5862                 err = -EFSCORRUPTED;
5863                 goto out;
5864         }
5865
5866         extent = path[depth].p_ext;
5867
5868         /* can't be mapped if the extent tree is empty */
5869         if (extent == NULL)
5870                 goto out;
5871
5872         first_lblk = le32_to_cpu(extent->ee_block);
5873         first_lclu = EXT4_B2C(sbi, first_lblk);
5874
5875         /*
5876          * Three possible outcomes at this point - found extent spanning
5877          * the target cluster, to the left of the target cluster, or to the
5878          * right of the target cluster.  The first two cases are handled here.
5879          * The last case indicates the target cluster is not mapped.
5880          */
5881         if (lclu >= first_lclu) {
5882                 last_lclu = EXT4_B2C(sbi, first_lblk +
5883                                      ext4_ext_get_actual_len(extent) - 1);
5884                 if (lclu <= last_lclu) {
5885                         mapped = 1;
5886                 } else {
5887                         first_lblk = ext4_ext_next_allocated_block(path);
5888                         first_lclu = EXT4_B2C(sbi, first_lblk);
5889                         if (lclu == first_lclu)
5890                                 mapped = 1;
5891                 }
5892         }
5893
5894 out:
5895         ext4_ext_drop_refs(path);
5896         kfree(path);
5897
5898         return err ? err : mapped;
5899 }
5900
5901 /*
5902  * Updates physical block address and unwritten status of extent
5903  * starting at lblk start and of len. If such an extent doesn't exist,
5904  * this function splits the extent tree appropriately to create an
5905  * extent like this.  This function is called in the fast commit
5906  * replay path.  Returns 0 on success and error on failure.
5907  */
5908 int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
5909                               int len, int unwritten, ext4_fsblk_t pblk)
5910 {
5911         struct ext4_ext_path *path = NULL, *ppath;
5912         struct ext4_extent *ex;
5913         int ret;
5914
5915         path = ext4_find_extent(inode, start, NULL, 0);
5916         if (IS_ERR(path))
5917                 return PTR_ERR(path);
5918         ex = path[path->p_depth].p_ext;
5919         if (!ex) {
5920                 ret = -EFSCORRUPTED;
5921                 goto out;
5922         }
5923
5924         if (le32_to_cpu(ex->ee_block) != start ||
5925                 ext4_ext_get_actual_len(ex) != len) {
5926                 /* We need to split this extent to match our extent first */
5927                 ppath = path;
5928                 down_write(&EXT4_I(inode)->i_data_sem);
5929                 ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
5930                 up_write(&EXT4_I(inode)->i_data_sem);
5931                 if (ret)
5932                         goto out;
5933                 kfree(path);
5934                 path = ext4_find_extent(inode, start, NULL, 0);
5935                 if (IS_ERR(path))
5936                         return -1;
5937                 ppath = path;
5938                 ex = path[path->p_depth].p_ext;
5939                 WARN_ON(le32_to_cpu(ex->ee_block) != start);
5940                 if (ext4_ext_get_actual_len(ex) != len) {
5941                         down_write(&EXT4_I(inode)->i_data_sem);
5942                         ret = ext4_force_split_extent_at(NULL, inode, &ppath,
5943                                                          start + len, 1);
5944                         up_write(&EXT4_I(inode)->i_data_sem);
5945                         if (ret)
5946                                 goto out;
5947                         kfree(path);
5948                         path = ext4_find_extent(inode, start, NULL, 0);
5949                         if (IS_ERR(path))
5950                                 return -EINVAL;
5951                         ex = path[path->p_depth].p_ext;
5952                 }
5953         }
5954         if (unwritten)
5955                 ext4_ext_mark_unwritten(ex);
5956         else
5957                 ext4_ext_mark_initialized(ex);
5958         ext4_ext_store_pblock(ex, pblk);
5959         down_write(&EXT4_I(inode)->i_data_sem);
5960         ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5961         up_write(&EXT4_I(inode)->i_data_sem);
5962 out:
5963         ext4_ext_drop_refs(path);
5964         kfree(path);
5965         ext4_mark_inode_dirty(NULL, inode);
5966         return ret;
5967 }
5968
5969 /* Try to shrink the extent tree */
5970 void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
5971 {
5972         struct ext4_ext_path *path = NULL;
5973         struct ext4_extent *ex;
5974         ext4_lblk_t old_cur, cur = 0;
5975
5976         while (cur < end) {
5977                 path = ext4_find_extent(inode, cur, NULL, 0);
5978                 if (IS_ERR(path))
5979                         return;
5980                 ex = path[path->p_depth].p_ext;
5981                 if (!ex) {
5982                         ext4_ext_drop_refs(path);
5983                         kfree(path);
5984                         ext4_mark_inode_dirty(NULL, inode);
5985                         return;
5986                 }
5987                 old_cur = cur;
5988                 cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5989                 if (cur <= old_cur)
5990                         cur = old_cur + 1;
5991                 ext4_ext_try_to_merge(NULL, inode, path, ex);
5992                 down_write(&EXT4_I(inode)->i_data_sem);
5993                 ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5994                 up_write(&EXT4_I(inode)->i_data_sem);
5995                 ext4_mark_inode_dirty(NULL, inode);
5996                 ext4_ext_drop_refs(path);
5997                 kfree(path);
5998         }
5999 }
6000
6001 /* Check if *cur is a hole and if it is, skip it */
6002 static int skip_hole(struct inode *inode, ext4_lblk_t *cur)
6003 {
6004         int ret;
6005         struct ext4_map_blocks map;
6006
6007         map.m_lblk = *cur;
6008         map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
6009
6010         ret = ext4_map_blocks(NULL, inode, &map, 0);
6011         if (ret < 0)
6012                 return ret;
6013         if (ret != 0)
6014                 return 0;
6015         *cur = *cur + map.m_len;
6016         return 0;
6017 }
6018
6019 /* Count number of blocks used by this inode and update i_blocks */
6020 int ext4_ext_replay_set_iblocks(struct inode *inode)
6021 {
6022         struct ext4_ext_path *path = NULL, *path2 = NULL;
6023         struct ext4_extent *ex;
6024         ext4_lblk_t cur = 0, end;
6025         int numblks = 0, i, ret = 0;
6026         ext4_fsblk_t cmp1, cmp2;
6027         struct ext4_map_blocks map;
6028
6029         /* Determin the size of the file first */
6030         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6031                                         EXT4_EX_NOCACHE);
6032         if (IS_ERR(path))
6033                 return PTR_ERR(path);
6034         ex = path[path->p_depth].p_ext;
6035         if (!ex) {
6036                 ext4_ext_drop_refs(path);
6037                 kfree(path);
6038                 goto out;
6039         }
6040         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6041         ext4_ext_drop_refs(path);
6042         kfree(path);
6043
6044         /* Count the number of data blocks */
6045         cur = 0;
6046         while (cur < end) {
6047                 map.m_lblk = cur;
6048                 map.m_len = end - cur;
6049                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6050                 if (ret < 0)
6051                         break;
6052                 if (ret > 0)
6053                         numblks += ret;
6054                 cur = cur + map.m_len;
6055         }
6056
6057         /*
6058          * Count the number of extent tree blocks. We do it by looking up
6059          * two successive extents and determining the difference between
6060          * their paths. When path is different for 2 successive extents
6061          * we compare the blocks in the path at each level and increment
6062          * iblocks by total number of differences found.
6063          */
6064         cur = 0;
6065         ret = skip_hole(inode, &cur);
6066         if (ret < 0)
6067                 goto out;
6068         path = ext4_find_extent(inode, cur, NULL, 0);
6069         if (IS_ERR(path))
6070                 goto out;
6071         numblks += path->p_depth;
6072         ext4_ext_drop_refs(path);
6073         kfree(path);
6074         while (cur < end) {
6075                 path = ext4_find_extent(inode, cur, NULL, 0);
6076                 if (IS_ERR(path))
6077                         break;
6078                 ex = path[path->p_depth].p_ext;
6079                 if (!ex) {
6080                         ext4_ext_drop_refs(path);
6081                         kfree(path);
6082                         return 0;
6083                 }
6084                 cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
6085                                         ext4_ext_get_actual_len(ex));
6086                 ret = skip_hole(inode, &cur);
6087                 if (ret < 0) {
6088                         ext4_ext_drop_refs(path);
6089                         kfree(path);
6090                         break;
6091                 }
6092                 path2 = ext4_find_extent(inode, cur, NULL, 0);
6093                 if (IS_ERR(path2)) {
6094                         ext4_ext_drop_refs(path);
6095                         kfree(path);
6096                         break;
6097                 }
6098                 ex = path2[path2->p_depth].p_ext;
6099                 for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
6100                         cmp1 = cmp2 = 0;
6101                         if (i <= path->p_depth)
6102                                 cmp1 = path[i].p_bh ?
6103                                         path[i].p_bh->b_blocknr : 0;
6104                         if (i <= path2->p_depth)
6105                                 cmp2 = path2[i].p_bh ?
6106                                         path2[i].p_bh->b_blocknr : 0;
6107                         if (cmp1 != cmp2 && cmp2 != 0)
6108                                 numblks++;
6109                 }
6110                 ext4_ext_drop_refs(path);
6111                 ext4_ext_drop_refs(path2);
6112                 kfree(path);
6113                 kfree(path2);
6114         }
6115
6116 out:
6117         inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
6118         ext4_mark_inode_dirty(NULL, inode);
6119         return 0;
6120 }
6121
6122 int ext4_ext_clear_bb(struct inode *inode)
6123 {
6124         struct ext4_ext_path *path = NULL;
6125         struct ext4_extent *ex;
6126         ext4_lblk_t cur = 0, end;
6127         int j, ret = 0;
6128         struct ext4_map_blocks map;
6129
6130         /* Determin the size of the file first */
6131         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6132                                         EXT4_EX_NOCACHE);
6133         if (IS_ERR(path))
6134                 return PTR_ERR(path);
6135         ex = path[path->p_depth].p_ext;
6136         if (!ex) {
6137                 ext4_ext_drop_refs(path);
6138                 kfree(path);
6139                 return 0;
6140         }
6141         end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6142         ext4_ext_drop_refs(path);
6143         kfree(path);
6144
6145         cur = 0;
6146         while (cur < end) {
6147                 map.m_lblk = cur;
6148                 map.m_len = end - cur;
6149                 ret = ext4_map_blocks(NULL, inode, &map, 0);
6150                 if (ret < 0)
6151                         break;
6152                 if (ret > 0) {
6153                         path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
6154                         if (!IS_ERR_OR_NULL(path)) {
6155                                 for (j = 0; j < path->p_depth; j++) {
6156
6157                                         ext4_mb_mark_bb(inode->i_sb,
6158                                                         path[j].p_block, 1, 0);
6159                                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6160                                                         0, path[j].p_block, 1, 1);
6161                                 }
6162                                 ext4_ext_drop_refs(path);
6163                                 kfree(path);
6164                         }
6165                         ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
6166                         ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6167                                         map.m_lblk, map.m_pblk, map.m_len, 1);
6168                 }
6169                 cur = cur + map.m_len;
6170         }
6171
6172         return 0;
6173 }