fs/ext4/extents.c

   1 /*
   2  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3  * Written by Alex Tomas <alex@clusterfs.com>
   4  *
   5  * Architecture independence:
   6  *   Copyright (c) 2005, Bull S.A.
   7  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21  */
  22
  23 /*
  24  * Extents support for EXT4
  25  *
  26  * TODO:
  27  *   - ext4*_error() should be used in some situations
  28  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29  *   - smart tree reduction
  30  */
  31
  32 #include <linux/fs.h>
  33 #include <linux/time.h>
  34 #include <linux/jbd2.h>
  35 #include <linux/highuid.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/quotaops.h>
  38 #include <linux/string.h>
  39 #include <linux/slab.h>
  40 #include <asm/uaccess.h>
  41 #include <linux/fiemap.h>
  42 #include <linux/backing-dev.h>
  43 #include "ext4_jbd2.h"
  44 #include "ext4_extents.h"
  45 #include "xattr.h"
  46
  47 #include <trace/events/ext4.h>
  48
  49 /*
  50  * used by extent splitting.
  51  */
  52 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  53                                         due to ENOSPC */
  54 #define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  55 #define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  56
  57 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  58 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  59
  60 static __le32 ext4_extent_block_csum(struct inode *inode,
  61                                      struct ext4_extent_header *eh)
  62 {
  63         struct ext4_inode_info *ei = EXT4_I(inode);
  64         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  65         __u32 csum;
  66
  67         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  68                            EXT4_EXTENT_TAIL_OFFSET(eh));
  69         return cpu_to_le32(csum);
  70 }
  71
  72 static int ext4_extent_block_csum_verify(struct inode *inode,
  73                                          struct ext4_extent_header *eh)
  74 {
  75         struct ext4_extent_tail *et;
  76
  77         if (!ext4_has_metadata_csum(inode->i_sb))
  78                 return 1;
  79
  80         et = find_ext4_extent_tail(eh);
  81         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  82                 return 0;
  83         return 1;
  84 }
  85
  86 static void ext4_extent_block_csum_set(struct inode *inode,
  87                                        struct ext4_extent_header *eh)
  88 {
  89         struct ext4_extent_tail *et;
  90
  91         if (!ext4_has_metadata_csum(inode->i_sb))
  92                 return;
  93
  94         et = find_ext4_extent_tail(eh);
  95         et->et_checksum = ext4_extent_block_csum(inode, eh);
  96 }
  97
  98 static int ext4_split_extent(handle_t *handle,
  99                                 struct inode *inode,
 100                                 struct ext4_ext_path **ppath,
 101                                 struct ext4_map_blocks *map,
 102                                 int split_flag,
 103                                 int flags);
 104
 105 static int ext4_split_extent_at(handle_t *handle,
 106                              struct inode *inode,
 107                              struct ext4_ext_path **ppath,
 108                              ext4_lblk_t split,
 109                              int split_flag,
 110                              int flags);
 111
 112 static int ext4_find_delayed_extent(struct inode *inode,
 113                                     struct extent_status *newes);
 114
 115 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 116                                             struct inode *inode,
 117                                             int needed)
 118 {
 119         int err;
 120
 121         if (!ext4_handle_valid(handle))
 122                 return 0;
 123         if (handle->h_buffer_credits > needed)
 124                 return 0;
 125         err = ext4_journal_extend(handle, needed);
 126         if (err <= 0)
 127                 return err;
 128         err = ext4_truncate_restart_trans(handle, inode, needed);
 129         if (err == 0)
 130                 err = -EAGAIN;
 131
 132         return err;
 133 }
 134
 135 /*
 136  * could return:
 137  *  - EROFS
 138  *  - ENOMEM
 139  */
 140 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 141                                 struct ext4_ext_path *path)
 142 {
 143         if (path->p_bh) {
 144                 /* path points to block */
 145                 BUFFER_TRACE(path->p_bh, "get_write_access");
 146                 return ext4_journal_get_write_access(handle, path->p_bh);
 147         }
 148         /* path points to leaf/index in inode body */
 149         /* we use in-core data, no need to protect them */
 150         return 0;
 151 }
 152
 153 /*
 154  * could return:
 155  *  - EROFS
 156  *  - ENOMEM
 157  *  - EIO
 158  */
 159 int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 160                      struct inode *inode, struct ext4_ext_path *path)
 161 {
 162         int err;
 163
 164         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 165         if (path->p_bh) {
 166                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 167                 /* path points to block */
 168                 err = __ext4_handle_dirty_metadata(where, line, handle,
 169                                                    inode, path->p_bh);
 170         } else {
 171                 /* path points to leaf/index in inode body */
 172                 err = ext4_mark_inode_dirty(handle, inode);
 173         }
 174         return err;
 175 }
 176
 177 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 178                               struct ext4_ext_path *path,
 179                               ext4_lblk_t block)
 180 {
 181         if (path) {
 182                 int depth = path->p_depth;
 183                 struct ext4_extent *ex;
 184
 185                 /*
 186                  * Try to predict block placement assuming that we are
 187                  * filling in a file which will eventually be
 188                  * non-sparse --- i.e., in the case of libbfd writing
 189                  * an ELF object sections out-of-order but in a way
 190                  * the eventually results in a contiguous object or
 191                  * executable file, or some database extending a table
 192                  * space file.  However, this is actually somewhat
 193                  * non-ideal if we are writing a sparse file such as
 194                  * qemu or KVM writing a raw image file that is going
 195                  * to stay fairly sparse, since it will end up
 196                  * fragmenting the file system's free space.  Maybe we
 197                  * should have some hueristics or some way to allow
 198                  * userspace to pass a hint to file system,
 199                  * especially if the latter case turns out to be
 200                  * common.
 201                  */
 202                 ex = path[depth].p_ext;
 203                 if (ex) {
 204                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 205                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 206
 207                         if (block > ext_block)
 208                                 return ext_pblk + (block - ext_block);
 209                         else
 210                                 return ext_pblk - (ext_block - block);
 211                 }
 212
 213                 /* it looks like index is empty;
 214                  * try to find starting block from index itself */
 215                 if (path[depth].p_bh)
 216                         return path[depth].p_bh->b_blocknr;
 217         }
 218
 219         /* OK. use inode's group */
 220         return ext4_inode_to_goal_block(inode);
 221 }
 222
 223 /*
 224  * Allocation for a meta data block
 225  */
 226 static ext4_fsblk_t
 227 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 228                         struct ext4_ext_path *path,
 229                         struct ext4_extent *ex, int *err, unsigned int flags)
 230 {
 231         ext4_fsblk_t goal, newblock;
 232
 233         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 234         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 235                                         NULL, err);
 236         return newblock;
 237 }
 238
 239 static inline int ext4_ext_space_block(struct inode *inode, int check)
 240 {
 241         int size;
 242
 243         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 244                         / sizeof(struct ext4_extent);
 245 #ifdef AGGRESSIVE_TEST
 246         if (!check && size > 6)
 247                 size = 6;
 248 #endif
 249         return size;
 250 }
 251
 252 static inline int ext4_ext_space_block_idx(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_idx);
 258 #ifdef AGGRESSIVE_TEST
 259         if (!check && size > 5)
 260                 size = 5;
 261 #endif
 262         return size;
 263 }
 264
 265 static inline int ext4_ext_space_root(struct inode *inode, int check)
 266 {
 267         int size;
 268
 269         size = sizeof(EXT4_I(inode)->i_data);
 270         size -= sizeof(struct ext4_extent_header);
 271         size /= sizeof(struct ext4_extent);
 272 #ifdef AGGRESSIVE_TEST
 273         if (!check && size > 3)
 274                 size = 3;
 275 #endif
 276         return size;
 277 }
 278
 279 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 280 {
 281         int size;
 282
 283         size = sizeof(EXT4_I(inode)->i_data);
 284         size -= sizeof(struct ext4_extent_header);
 285         size /= sizeof(struct ext4_extent_idx);
 286 #ifdef AGGRESSIVE_TEST
 287         if (!check && size > 4)
 288                 size = 4;
 289 #endif
 290         return size;
 291 }
 292
 293 static inline int
 294 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 295                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 296                            int nofail)
 297 {
 298         struct ext4_ext_path *path = *ppath;
 299         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 300
 301         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 302                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 303                         EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
 304                         (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
 305 }
 306
 307 /*
 308  * Calculate the number of metadata blocks needed
 309  * to allocate @blocks
 310  * Worse case is one block per extent
 311  */
 312 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 313 {
 314         struct ext4_inode_info *ei = EXT4_I(inode);
 315         int idxs;
 316
 317         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 318                 / sizeof(struct ext4_extent_idx));
 319
 320         /*
 321          * If the new delayed allocation block is contiguous with the
 322          * previous da block, it can share index blocks with the
 323          * previous block, so we only need to allocate a new index
 324          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 325          * an additional index block, and at ldxs**3 blocks, yet
 326          * another index blocks.
 327          */
 328         if (ei->i_da_metadata_calc_len &&
 329             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 330                 int num = 0;
 331
 332                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 333                         num++;
 334                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 335                         num++;
 336                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 337                         num++;
 338                         ei->i_da_metadata_calc_len = 0;
 339                 } else
 340                         ei->i_da_metadata_calc_len++;
 341                 ei->i_da_metadata_calc_last_lblock++;
 342                 return num;
 343         }
 344
 345         /*
 346          * In the worst case we need a new set of index blocks at
 347          * every level of the inode's extent tree.
 348          */
 349         ei->i_da_metadata_calc_len = 1;
 350         ei->i_da_metadata_calc_last_lblock = lblock;
 351         return ext_depth(inode) + 1;
 352 }
 353
 354 static int
 355 ext4_ext_max_entries(struct inode *inode, int depth)
 356 {
 357         int max;
 358
 359         if (depth == ext_depth(inode)) {
 360                 if (depth == 0)
 361                         max = ext4_ext_space_root(inode, 1);
 362                 else
 363                         max = ext4_ext_space_root_idx(inode, 1);
 364         } else {
 365                 if (depth == 0)
 366                         max = ext4_ext_space_block(inode, 1);
 367                 else
 368                         max = ext4_ext_space_block_idx(inode, 1);
 369         }
 370
 371         return max;
 372 }
 373
 374 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 375 {
 376         ext4_fsblk_t block = ext4_ext_pblock(ext);
 377         int len = ext4_ext_get_actual_len(ext);
 378         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 379         ext4_lblk_t last = lblock + len - 1;
 380
 381         if (len == 0 || lblock > last)
 382                 return 0;
 383         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 384 }
 385
 386 static int ext4_valid_extent_idx(struct inode *inode,
 387                                 struct ext4_extent_idx *ext_idx)
 388 {
 389         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 390
 391         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 392 }
 393
 394 static int ext4_valid_extent_entries(struct inode *inode,
 395                                 struct ext4_extent_header *eh,
 396                                 int depth)
 397 {
 398         unsigned short entries;
 399         if (eh->eh_entries == 0)
 400                 return 1;
 401
 402         entries = le16_to_cpu(eh->eh_entries);
 403
 404         if (depth == 0) {
 405                 /* leaf entries */
 406                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 407                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 408                 ext4_fsblk_t pblock = 0;
 409                 ext4_lblk_t lblock = 0;
 410                 ext4_lblk_t prev = 0;
 411                 int len = 0;
 412                 while (entries) {
 413                         if (!ext4_valid_extent(inode, ext))
 414                                 return 0;
 415
 416                         /* Check for overlapping extents */
 417                         lblock = le32_to_cpu(ext->ee_block);
 418                         len = ext4_ext_get_actual_len(ext);
 419                         if ((lblock <= prev) && prev) {
 420                                 pblock = ext4_ext_pblock(ext);
 421                                 es->s_last_error_block = cpu_to_le64(pblock);
 422                                 return 0;
 423                         }
 424                         ext++;
 425                         entries--;
 426                         prev = lblock + len - 1;
 427                 }
 428         } else {
 429                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 430                 while (entries) {
 431                         if (!ext4_valid_extent_idx(inode, ext_idx))
 432                                 return 0;
 433                         ext_idx++;
 434                         entries--;
 435                 }
 436         }
 437         return 1;
 438 }
 439
 440 static int __ext4_ext_check(const char *function, unsigned int line,
 441                             struct inode *inode, struct ext4_extent_header *eh,
 442                             int depth, ext4_fsblk_t pblk)
 443 {
 444         const char *error_msg;
 445         int max = 0, err = -EFSCORRUPTED;
 446
 447         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 448                 error_msg = "invalid magic";
 449                 goto corrupted;
 450         }
 451         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 452                 error_msg = "unexpected eh_depth";
 453                 goto corrupted;
 454         }
 455         if (unlikely(eh->eh_max == 0)) {
 456                 error_msg = "invalid eh_max";
 457                 goto corrupted;
 458         }
 459         max = ext4_ext_max_entries(inode, depth);
 460         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 461                 error_msg = "too large eh_max";
 462                 goto corrupted;
 463         }
 464         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 465                 error_msg = "invalid eh_entries";
 466                 goto corrupted;
 467         }
 468         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 469                 error_msg = "invalid extent entries";
 470                 goto corrupted;
 471         }
 472         /* Verify checksum on non-root extent tree nodes */
 473         if (ext_depth(inode) != depth &&
 474             !ext4_extent_block_csum_verify(inode, eh)) {
 475                 error_msg = "extent tree corrupted";
 476                 err = -EFSBADCRC;
 477                 goto corrupted;
 478         }
 479         return 0;
 480
 481 corrupted:
 482         ext4_error_inode(inode, function, line, 0,
 483                          "pblk %llu bad header/extent: %s - magic %x, "
 484                          "entries %u, max %u(%u), depth %u(%u)",
 485                          (unsigned long long) pblk, error_msg,
 486                          le16_to_cpu(eh->eh_magic),
 487                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 488                          max, le16_to_cpu(eh->eh_depth), depth);
 489         return err;
 490 }
 491
 492 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 493         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 494
 495 int ext4_ext_check_inode(struct inode *inode)
 496 {
 497         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 498 }
 499
 500 static struct buffer_head *
 501 __read_extent_tree_block(const char *function, unsigned int line,
 502                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 503                          int flags)
 504 {
 505         struct buffer_head              *bh;
 506         int                             err;
 507
 508         bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
 509         if (unlikely(!bh))
 510                 return ERR_PTR(-ENOMEM);
 511
 512         if (!bh_uptodate_or_lock(bh)) {
 513                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 514                 err = bh_submit_read(bh);
 515                 if (err < 0)
 516                         goto errout;
 517         }
 518         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 519                 return bh;
 520         err = __ext4_ext_check(function, line, inode,
 521                                ext_block_hdr(bh), depth, pblk);
 522         if (err)
 523                 goto errout;
 524         set_buffer_verified(bh);
 525         /*
 526          * If this is a leaf block, cache all of its entries
 527          */
 528         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 529                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 530                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 531                 ext4_lblk_t prev = 0;
 532                 int i;
 533
 534                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 535                         unsigned int status = EXTENT_STATUS_WRITTEN;
 536                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 537                         int len = ext4_ext_get_actual_len(ex);
 538
 539                         if (prev && (prev != lblk))
 540                                 ext4_es_cache_extent(inode, prev,
 541                                                      lblk - prev, ~0,
 542                                                      EXTENT_STATUS_HOLE);
 543
 544                         if (ext4_ext_is_unwritten(ex))
 545                                 status = EXTENT_STATUS_UNWRITTEN;
 546                         ext4_es_cache_extent(inode, lblk, len,
 547                                              ext4_ext_pblock(ex), status);
 548                         prev = lblk + len;
 549                 }
 550         }
 551         return bh;
 552 errout:
 553         put_bh(bh);
 554         return ERR_PTR(err);
 555
 556 }
 557
 558 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 559         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 560                                  (depth), (flags))
 561
 562 /*
 563  * This function is called to cache a file's extent information in the
 564  * extent status tree
 565  */
 566 int ext4_ext_precache(struct inode *inode)
 567 {
 568         struct ext4_inode_info *ei = EXT4_I(inode);
 569         struct ext4_ext_path *path = NULL;
 570         struct buffer_head *bh;
 571         int i = 0, depth, ret = 0;
 572
 573         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 574                 return 0;       /* not an extent-mapped inode */
 575
 576         down_read(&ei->i_data_sem);
 577         depth = ext_depth(inode);
 578
 579         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 580                        GFP_NOFS);
 581         if (path == NULL) {
 582                 up_read(&ei->i_data_sem);
 583                 return -ENOMEM;
 584         }
 585
 586         /* Don't cache anything if there are no external extent blocks */
 587         if (depth == 0)
 588                 goto out;
 589         path[0].p_hdr = ext_inode_hdr(inode);
 590         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 591         if (ret)
 592                 goto out;
 593         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 594         while (i >= 0) {
 595                 /*
 596                  * If this is a leaf block or we've reached the end of
 597                  * the index block, go up
 598                  */
 599                 if ((i == depth) ||
 600                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 601                         brelse(path[i].p_bh);
 602                         path[i].p_bh = NULL;
 603                         i--;
 604                         continue;
 605                 }
 606                 bh = read_extent_tree_block(inode,
 607                                             ext4_idx_pblock(path[i].p_idx++),
 608                                             depth - i - 1,
 609                                             EXT4_EX_FORCE_CACHE);
 610                 if (IS_ERR(bh)) {
 611                         ret = PTR_ERR(bh);
 612                         break;
 613                 }
 614                 i++;
 615                 path[i].p_bh = bh;
 616                 path[i].p_hdr = ext_block_hdr(bh);
 617                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 618         }
 619         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 620 out:
 621         up_read(&ei->i_data_sem);
 622         ext4_ext_drop_refs(path);
 623         kfree(path);
 624         return ret;
 625 }
 626
 627 #ifdef EXT_DEBUG
 628 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 629 {
 630         int k, l = path->p_depth;
 631
 632         ext_debug("path:");
 633         for (k = 0; k <= l; k++, path++) {
 634                 if (path->p_idx) {
 635                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 636                             ext4_idx_pblock(path->p_idx));
 637                 } else if (path->p_ext) {
 638                         ext_debug("  %d:[%d]%d:%llu ",
 639                                   le32_to_cpu(path->p_ext->ee_block),
 640                                   ext4_ext_is_unwritten(path->p_ext),
 641                                   ext4_ext_get_actual_len(path->p_ext),
 642                                   ext4_ext_pblock(path->p_ext));
 643                 } else
 644                         ext_debug("  []");
 645         }
 646         ext_debug("\n");
 647 }
 648
 649 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 650 {
 651         int depth = ext_depth(inode);
 652         struct ext4_extent_header *eh;
 653         struct ext4_extent *ex;
 654         int i;
 655
 656         if (!path)
 657                 return;
 658
 659         eh = path[depth].p_hdr;
 660         ex = EXT_FIRST_EXTENT(eh);
 661
 662         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 663
 664         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 665                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 666                           ext4_ext_is_unwritten(ex),
 667                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 668         }
 669         ext_debug("\n");
 670 }
 671
 672 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 673                         ext4_fsblk_t newblock, int level)
 674 {
 675         int depth = ext_depth(inode);
 676         struct ext4_extent *ex;
 677
 678         if (depth != level) {
 679                 struct ext4_extent_idx *idx;
 680                 idx = path[level].p_idx;
 681                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 682                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 683                                         le32_to_cpu(idx->ei_block),
 684                                         ext4_idx_pblock(idx),
 685                                         newblock);
 686                         idx++;
 687                 }
 688
 689                 return;
 690         }
 691
 692         ex = path[depth].p_ext;
 693         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 694                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 695                                 le32_to_cpu(ex->ee_block),
 696                                 ext4_ext_pblock(ex),
 697                                 ext4_ext_is_unwritten(ex),
 698                                 ext4_ext_get_actual_len(ex),
 699                                 newblock);
 700                 ex++;
 701         }
 702 }
 703
 704 #else
 705 #define ext4_ext_show_path(inode, path)
 706 #define ext4_ext_show_leaf(inode, path)
 707 #define ext4_ext_show_move(inode, path, newblock, level)
 708 #endif
 709
 710 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 711 {
 712         int depth, i;
 713
 714         if (!path)
 715                 return;
 716         depth = path->p_depth;
 717         for (i = 0; i <= depth; i++, path++)
 718                 if (path->p_bh) {
 719                         brelse(path->p_bh);
 720                         path->p_bh = NULL;
 721                 }
 722 }
 723
 724 /*
 725  * ext4_ext_binsearch_idx:
 726  * binary search for the closest index of the given block
 727  * the header must be checked before calling this
 728  */
 729 static void
 730 ext4_ext_binsearch_idx(struct inode *inode,
 731                         struct ext4_ext_path *path, ext4_lblk_t block)
 732 {
 733         struct ext4_extent_header *eh = path->p_hdr;
 734         struct ext4_extent_idx *r, *l, *m;
 735
 736
 737         ext_debug("binsearch for %u(idx):  ", block);
 738
 739         l = EXT_FIRST_INDEX(eh) + 1;
 740         r = EXT_LAST_INDEX(eh);
 741         while (l <= r) {
 742                 m = l + (r - l) / 2;
 743                 if (block < le32_to_cpu(m->ei_block))
 744                         r = m - 1;
 745                 else
 746                         l = m + 1;
 747                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 748                                 m, le32_to_cpu(m->ei_block),
 749                                 r, le32_to_cpu(r->ei_block));
 750         }
 751
 752         path->p_idx = l - 1;
 753         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 754                   ext4_idx_pblock(path->p_idx));
 755
 756 #ifdef CHECK_BINSEARCH
 757         {
 758                 struct ext4_extent_idx *chix, *ix;
 759                 int k;
 760
 761                 chix = ix = EXT_FIRST_INDEX(eh);
 762                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 763                   if (k != 0 &&
 764                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 765                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 766                                        "first=0x%p\n", k,
 767                                        ix, EXT_FIRST_INDEX(eh));
 768                                 printk(KERN_DEBUG "%u <= %u\n",
 769                                        le32_to_cpu(ix->ei_block),
 770                                        le32_to_cpu(ix[-1].ei_block));
 771                         }
 772                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 773                                            <= le32_to_cpu(ix[-1].ei_block));
 774                         if (block < le32_to_cpu(ix->ei_block))
 775                                 break;
 776                         chix = ix;
 777                 }
 778                 BUG_ON(chix != path->p_idx);
 779         }
 780 #endif
 781
 782 }
 783
 784 /*
 785  * ext4_ext_binsearch:
 786  * binary search for closest extent of the given block
 787  * the header must be checked before calling this
 788  */
 789 static void
 790 ext4_ext_binsearch(struct inode *inode,
 791                 struct ext4_ext_path *path, ext4_lblk_t block)
 792 {
 793         struct ext4_extent_header *eh = path->p_hdr;
 794         struct ext4_extent *r, *l, *m;
 795
 796         if (eh->eh_entries == 0) {
 797                 /*
 798                  * this leaf is empty:
 799                  * we get such a leaf in split/add case
 800                  */
 801                 return;
 802         }
 803
 804         ext_debug("binsearch for %u:  ", block);
 805
 806         l = EXT_FIRST_EXTENT(eh) + 1;
 807         r = EXT_LAST_EXTENT(eh);
 808
 809         while (l <= r) {
 810                 m = l + (r - l) / 2;
 811                 if (block < le32_to_cpu(m->ee_block))
 812                         r = m - 1;
 813                 else
 814                         l = m + 1;
 815                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 816                                 m, le32_to_cpu(m->ee_block),
 817                                 r, le32_to_cpu(r->ee_block));
 818         }
 819
 820         path->p_ext = l - 1;
 821         ext_debug("  -> %d:%llu:[%d]%d ",
 822                         le32_to_cpu(path->p_ext->ee_block),
 823                         ext4_ext_pblock(path->p_ext),
 824                         ext4_ext_is_unwritten(path->p_ext),
 825                         ext4_ext_get_actual_len(path->p_ext));
 826
 827 #ifdef CHECK_BINSEARCH
 828         {
 829                 struct ext4_extent *chex, *ex;
 830                 int k;
 831
 832                 chex = ex = EXT_FIRST_EXTENT(eh);
 833                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 834                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 835                                           <= le32_to_cpu(ex[-1].ee_block));
 836                         if (block < le32_to_cpu(ex->ee_block))
 837                                 break;
 838                         chex = ex;
 839                 }
 840                 BUG_ON(chex != path->p_ext);
 841         }
 842 #endif
 843
 844 }
 845
 846 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 847 {
 848         struct ext4_extent_header *eh;
 849
 850         eh = ext_inode_hdr(inode);
 851         eh->eh_depth = 0;
 852         eh->eh_entries = 0;
 853         eh->eh_magic = EXT4_EXT_MAGIC;
 854         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 855         ext4_mark_inode_dirty(handle, inode);
 856         return 0;
 857 }
 858
 859 struct ext4_ext_path *
 860 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 861                  struct ext4_ext_path **orig_path, int flags)
 862 {
 863         struct ext4_extent_header *eh;
 864         struct buffer_head *bh;
 865         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 866         short int depth, i, ppos = 0;
 867         int ret;
 868
 869         eh = ext_inode_hdr(inode);
 870         depth = ext_depth(inode);
 871
 872         if (path) {
 873                 ext4_ext_drop_refs(path);
 874                 if (depth > path[0].p_maxdepth) {
 875                         kfree(path);
 876                         *orig_path = path = NULL;
 877                 }
 878         }
 879         if (!path) {
 880                 /* account possible depth increase */
 881                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 882                                 GFP_NOFS);
 883                 if (unlikely(!path))
 884                         return ERR_PTR(-ENOMEM);
 885                 path[0].p_maxdepth = depth + 1;
 886         }
 887         path[0].p_hdr = eh;
 888         path[0].p_bh = NULL;
 889
 890         i = depth;
 891         /* walk through the tree */
 892         while (i) {
 893                 ext_debug("depth %d: num %d, max %d\n",
 894                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 895
 896                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 897                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 898                 path[ppos].p_depth = i;
 899                 path[ppos].p_ext = NULL;
 900
 901                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 902                                             flags);
 903                 if (IS_ERR(bh)) {
 904                         ret = PTR_ERR(bh);
 905                         goto err;
 906                 }
 907
 908                 eh = ext_block_hdr(bh);
 909                 ppos++;
 910                 if (unlikely(ppos > depth)) {
 911                         put_bh(bh);
 912                         EXT4_ERROR_INODE(inode,
 913                                          "ppos %d > depth %d", ppos, depth);
 914                         ret = -EFSCORRUPTED;
 915                         goto err;
 916                 }
 917                 path[ppos].p_bh = bh;
 918                 path[ppos].p_hdr = eh;
 919         }
 920
 921         path[ppos].p_depth = i;
 922         path[ppos].p_ext = NULL;
 923         path[ppos].p_idx = NULL;
 924
 925         /* find extent */
 926         ext4_ext_binsearch(inode, path + ppos, block);
 927         /* if not an empty leaf */
 928         if (path[ppos].p_ext)
 929                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 930
 931         ext4_ext_show_path(inode, path);
 932
 933         return path;
 934
 935 err:
 936         ext4_ext_drop_refs(path);
 937         kfree(path);
 938         if (orig_path)
 939                 *orig_path = NULL;
 940         return ERR_PTR(ret);
 941 }
 942
 943 /*
 944  * ext4_ext_insert_index:
 945  * insert new index [@logical;@ptr] into the block at @curp;
 946  * check where to insert: before @curp or after @curp
 947  */
 948 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 949                                  struct ext4_ext_path *curp,
 950                                  int logical, ext4_fsblk_t ptr)
 951 {
 952         struct ext4_extent_idx *ix;
 953         int len, err;
 954
 955         err = ext4_ext_get_access(handle, inode, curp);
 956         if (err)
 957                 return err;
 958
 959         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 960                 EXT4_ERROR_INODE(inode,
 961                                  "logical %d == ei_block %d!",
 962                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 963                 return -EFSCORRUPTED;
 964         }
 965
 966         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 967                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 968                 EXT4_ERROR_INODE(inode,
 969                                  "eh_entries %d >= eh_max %d!",
 970                                  le16_to_cpu(curp->p_hdr->eh_entries),
 971                                  le16_to_cpu(curp->p_hdr->eh_max));
 972                 return -EFSCORRUPTED;
 973         }
 974
 975         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 976                 /* insert after */
 977                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 978                 ix = curp->p_idx + 1;
 979         } else {
 980                 /* insert before */
 981                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 982                 ix = curp->p_idx;
 983         }
 984
 985         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 986         BUG_ON(len < 0);
 987         if (len > 0) {
 988                 ext_debug("insert new index %d: "
 989                                 "move %d indices from 0x%p to 0x%p\n",
 990                                 logical, len, ix, ix + 1);
 991                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 992         }
 993
 994         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 995                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 996                 return -EFSCORRUPTED;
 997         }
 998
 999         ix->ei_block = cpu_to_le32(logical);
1000         ext4_idx_store_pblock(ix, ptr);
1001         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1002
1003         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1004                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1005                 return -EFSCORRUPTED;
1006         }
1007
1008         err = ext4_ext_dirty(handle, inode, curp);
1009         ext4_std_error(inode->i_sb, err);
1010
1011         return err;
1012 }
1013
1014 /*
1015  * ext4_ext_split:
1016  * inserts new subtree into the path, using free index entry
1017  * at depth @at:
1018  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1019  * - makes decision where to split
1020  * - moves remaining extents and index entries (right to the split point)
1021  *   into the newly allocated blocks
1022  * - initializes subtree
1023  */
1024 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1025                           unsigned int flags,
1026                           struct ext4_ext_path *path,
1027                           struct ext4_extent *newext, int at)
1028 {
1029         struct buffer_head *bh = NULL;
1030         int depth = ext_depth(inode);
1031         struct ext4_extent_header *neh;
1032         struct ext4_extent_idx *fidx;
1033         int i = at, k, m, a;
1034         ext4_fsblk_t newblock, oldblock;
1035         __le32 border;
1036         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1037         int err = 0;
1038
1039         /* make decision: where to split? */
1040         /* FIXME: now decision is simplest: at current extent */
1041
1042         /* if current leaf will be split, then we should use
1043          * border from split point */
1044         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1045                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1046                 return -EFSCORRUPTED;
1047         }
1048         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1049                 border = path[depth].p_ext[1].ee_block;
1050                 ext_debug("leaf will be split."
1051                                 " next leaf starts at %d\n",
1052                                   le32_to_cpu(border));
1053         } else {
1054                 border = newext->ee_block;
1055                 ext_debug("leaf will be added."
1056                                 " next leaf starts at %d\n",
1057                                 le32_to_cpu(border));
1058         }
1059
1060         /*
1061          * If error occurs, then we break processing
1062          * and mark filesystem read-only. index won't
1063          * be inserted and tree will be in consistent
1064          * state. Next mount will repair buffers too.
1065          */
1066
1067         /*
1068          * Get array to track all allocated blocks.
1069          * We need this to handle errors and free blocks
1070          * upon them.
1071          */
1072         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1073         if (!ablocks)
1074                 return -ENOMEM;
1075
1076         /* allocate all needed blocks */
1077         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1078         for (a = 0; a < depth - at; a++) {
1079                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1080                                                    newext, &err, flags);
1081                 if (newblock == 0)
1082                         goto cleanup;
1083                 ablocks[a] = newblock;
1084         }
1085
1086         /* initialize new leaf */
1087         newblock = ablocks[--a];
1088         if (unlikely(newblock == 0)) {
1089                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1090                 err = -EFSCORRUPTED;
1091                 goto cleanup;
1092         }
1093         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1094         if (unlikely(!bh)) {
1095                 err = -ENOMEM;
1096                 goto cleanup;
1097         }
1098         lock_buffer(bh);
1099
1100         err = ext4_journal_get_create_access(handle, bh);
1101         if (err)
1102                 goto cleanup;
1103
1104         neh = ext_block_hdr(bh);
1105         neh->eh_entries = 0;
1106         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1107         neh->eh_magic = EXT4_EXT_MAGIC;
1108         neh->eh_depth = 0;
1109
1110         /* move remainder of path[depth] to the new leaf */
1111         if (unlikely(path[depth].p_hdr->eh_entries !=
1112                      path[depth].p_hdr->eh_max)) {
1113                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1114                                  path[depth].p_hdr->eh_entries,
1115                                  path[depth].p_hdr->eh_max);
1116                 err = -EFSCORRUPTED;
1117                 goto cleanup;
1118         }
1119         /* start copy from next extent */
1120         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1121         ext4_ext_show_move(inode, path, newblock, depth);
1122         if (m) {
1123                 struct ext4_extent *ex;
1124                 ex = EXT_FIRST_EXTENT(neh);
1125                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1126                 le16_add_cpu(&neh->eh_entries, m);
1127         }
1128
1129         ext4_extent_block_csum_set(inode, neh);
1130         set_buffer_uptodate(bh);
1131         unlock_buffer(bh);
1132
1133         err = ext4_handle_dirty_metadata(handle, inode, bh);
1134         if (err)
1135                 goto cleanup;
1136         brelse(bh);
1137         bh = NULL;
1138
1139         /* correct old leaf */
1140         if (m) {
1141                 err = ext4_ext_get_access(handle, inode, path + depth);
1142                 if (err)
1143                         goto cleanup;
1144                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1145                 err = ext4_ext_dirty(handle, inode, path + depth);
1146                 if (err)
1147                         goto cleanup;
1148
1149         }
1150
1151         /* create intermediate indexes */
1152         k = depth - at - 1;
1153         if (unlikely(k < 0)) {
1154                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1155                 err = -EFSCORRUPTED;
1156                 goto cleanup;
1157         }
1158         if (k)
1159                 ext_debug("create %d intermediate indices\n", k);
1160         /* insert new index into current index block */
1161         /* current depth stored in i var */
1162         i = depth - 1;
1163         while (k--) {
1164                 oldblock = newblock;
1165                 newblock = ablocks[--a];
1166                 bh = sb_getblk(inode->i_sb, newblock);
1167                 if (unlikely(!bh)) {
1168                         err = -ENOMEM;
1169                         goto cleanup;
1170                 }
1171                 lock_buffer(bh);
1172
1173                 err = ext4_journal_get_create_access(handle, bh);
1174                 if (err)
1175                         goto cleanup;
1176
1177                 neh = ext_block_hdr(bh);
1178                 neh->eh_entries = cpu_to_le16(1);
1179                 neh->eh_magic = EXT4_EXT_MAGIC;
1180                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1181                 neh->eh_depth = cpu_to_le16(depth - i);
1182                 fidx = EXT_FIRST_INDEX(neh);
1183                 fidx->ei_block = border;
1184                 ext4_idx_store_pblock(fidx, oldblock);
1185
1186                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1187                                 i, newblock, le32_to_cpu(border), oldblock);
1188
1189                 /* move remainder of path[i] to the new index block */
1190                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1191                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1192                         EXT4_ERROR_INODE(inode,
1193                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1194                                          le32_to_cpu(path[i].p_ext->ee_block));
1195                         err = -EFSCORRUPTED;
1196                         goto cleanup;
1197                 }
1198                 /* start copy indexes */
1199                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1200                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1201                                 EXT_MAX_INDEX(path[i].p_hdr));
1202                 ext4_ext_show_move(inode, path, newblock, i);
1203                 if (m) {
1204                         memmove(++fidx, path[i].p_idx,
1205                                 sizeof(struct ext4_extent_idx) * m);
1206                         le16_add_cpu(&neh->eh_entries, m);
1207                 }
1208                 ext4_extent_block_csum_set(inode, neh);
1209                 set_buffer_uptodate(bh);
1210                 unlock_buffer(bh);
1211
1212                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1213                 if (err)
1214                         goto cleanup;
1215                 brelse(bh);
1216                 bh = NULL;
1217
1218                 /* correct old index */
1219                 if (m) {
1220                         err = ext4_ext_get_access(handle, inode, path + i);
1221                         if (err)
1222                                 goto cleanup;
1223                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1224                         err = ext4_ext_dirty(handle, inode, path + i);
1225                         if (err)
1226                                 goto cleanup;
1227                 }
1228
1229                 i--;
1230         }
1231
1232         /* insert new index */
1233         err = ext4_ext_insert_index(handle, inode, path + at,
1234                                     le32_to_cpu(border), newblock);
1235
1236 cleanup:
1237         if (bh) {
1238                 if (buffer_locked(bh))
1239                         unlock_buffer(bh);
1240                 brelse(bh);
1241         }
1242
1243         if (err) {
1244                 /* free all allocated blocks in error case */
1245                 for (i = 0; i < depth; i++) {
1246                         if (!ablocks[i])
1247                                 continue;
1248                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1249                                          EXT4_FREE_BLOCKS_METADATA);
1250                 }
1251         }
1252         kfree(ablocks);
1253
1254         return err;
1255 }
1256
1257 /*
1258  * ext4_ext_grow_indepth:
1259  * implements tree growing procedure:
1260  * - allocates new block
1261  * - moves top-level data (index block or leaf) into the new block
1262  * - initializes new top-level, creating index that points to the
1263  *   just created block
1264  */
1265 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1266                                  unsigned int flags)
1267 {
1268         struct ext4_extent_header *neh;
1269         struct buffer_head *bh;
1270         ext4_fsblk_t newblock, goal = 0;
1271         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1272         int err = 0;
1273
1274         /* Try to prepend new index to old one */
1275         if (ext_depth(inode))
1276                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1277         if (goal > le32_to_cpu(es->s_first_data_block)) {
1278                 flags |= EXT4_MB_HINT_TRY_GOAL;
1279                 goal--;
1280         } else
1281                 goal = ext4_inode_to_goal_block(inode);
1282         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1283                                         NULL, &err);
1284         if (newblock == 0)
1285                 return err;
1286
1287         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1288         if (unlikely(!bh))
1289                 return -ENOMEM;
1290         lock_buffer(bh);
1291
1292         err = ext4_journal_get_create_access(handle, bh);
1293         if (err) {
1294                 unlock_buffer(bh);
1295                 goto out;
1296         }
1297
1298         /* move top-level index/leaf into new block */
1299         memmove(bh->b_data, EXT4_I(inode)->i_data,
1300                 sizeof(EXT4_I(inode)->i_data));
1301
1302         /* set size of new block */
1303         neh = ext_block_hdr(bh);
1304         /* old root could have indexes or leaves
1305          * so calculate e_max right way */
1306         if (ext_depth(inode))
1307                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1308         else
1309                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1310         neh->eh_magic = EXT4_EXT_MAGIC;
1311         ext4_extent_block_csum_set(inode, neh);
1312         set_buffer_uptodate(bh);
1313         unlock_buffer(bh);
1314
1315         err = ext4_handle_dirty_metadata(handle, inode, bh);
1316         if (err)
1317                 goto out;
1318
1319         /* Update top-level index: num,max,pointer */
1320         neh = ext_inode_hdr(inode);
1321         neh->eh_entries = cpu_to_le16(1);
1322         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1323         if (neh->eh_depth == 0) {
1324                 /* Root extent block becomes index block */
1325                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1326                 EXT_FIRST_INDEX(neh)->ei_block =
1327                         EXT_FIRST_EXTENT(neh)->ee_block;
1328         }
1329         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1330                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1331                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1332                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1333
1334         le16_add_cpu(&neh->eh_depth, 1);
1335         ext4_mark_inode_dirty(handle, inode);
1336 out:
1337         brelse(bh);
1338
1339         return err;
1340 }
1341
1342 /*
1343  * ext4_ext_create_new_leaf:
1344  * finds empty index and adds new leaf.
1345  * if no free index is found, then it requests in-depth growing.
1346  */
1347 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1348                                     unsigned int mb_flags,
1349                                     unsigned int gb_flags,
1350                                     struct ext4_ext_path **ppath,
1351                                     struct ext4_extent *newext)
1352 {
1353         struct ext4_ext_path *path = *ppath;
1354         struct ext4_ext_path *curp;
1355         int depth, i, err = 0;
1356
1357 repeat:
1358         i = depth = ext_depth(inode);
1359
1360         /* walk up to the tree and look for free index entry */
1361         curp = path + depth;
1362         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1363                 i--;
1364                 curp--;
1365         }
1366
1367         /* we use already allocated block for index block,
1368          * so subsequent data blocks should be contiguous */
1369         if (EXT_HAS_FREE_INDEX(curp)) {
1370                 /* if we found index with free entry, then use that
1371                  * entry: create all needed subtree and add new leaf */
1372                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1373                 if (err)
1374                         goto out;
1375
1376                 /* refill path */
1377                 path = ext4_find_extent(inode,
1378                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1379                                     ppath, gb_flags);
1380                 if (IS_ERR(path))
1381                         err = PTR_ERR(path);
1382         } else {
1383                 /* tree is full, time to grow in depth */
1384                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1385                 if (err)
1386                         goto out;
1387
1388                 /* refill path */
1389                 path = ext4_find_extent(inode,
1390                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1391                                     ppath, gb_flags);
1392                 if (IS_ERR(path)) {
1393                         err = PTR_ERR(path);
1394                         goto out;
1395                 }
1396
1397                 /*
1398                  * only first (depth 0 -> 1) produces free space;
1399                  * in all other cases we have to split the grown tree
1400                  */
1401                 depth = ext_depth(inode);
1402                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1403                         /* now we need to split */
1404                         goto repeat;
1405                 }
1406         }
1407
1408 out:
1409         return err;
1410 }
1411
1412 /*
1413  * search the closest allocated block to the left for *logical
1414  * and returns it at @logical + it's physical address at @phys
1415  * if *logical is the smallest allocated block, the function
1416  * returns 0 at @phys
1417  * return value contains 0 (success) or error code
1418  */
1419 static int ext4_ext_search_left(struct inode *inode,
1420                                 struct ext4_ext_path *path,
1421                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1422 {
1423         struct ext4_extent_idx *ix;
1424         struct ext4_extent *ex;
1425         int depth, ee_len;
1426
1427         if (unlikely(path == NULL)) {
1428                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1429                 return -EFSCORRUPTED;
1430         }
1431         depth = path->p_depth;
1432         *phys = 0;
1433
1434         if (depth == 0 && path->p_ext == NULL)
1435                 return 0;
1436
1437         /* usually extent in the path covers blocks smaller
1438          * then *logical, but it can be that extent is the
1439          * first one in the file */
1440
1441         ex = path[depth].p_ext;
1442         ee_len = ext4_ext_get_actual_len(ex);
1443         if (*logical < le32_to_cpu(ex->ee_block)) {
1444                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1445                         EXT4_ERROR_INODE(inode,
1446                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1447                                          *logical, le32_to_cpu(ex->ee_block));
1448                         return -EFSCORRUPTED;
1449                 }
1450                 while (--depth >= 0) {
1451                         ix = path[depth].p_idx;
1452                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1453                                 EXT4_ERROR_INODE(inode,
1454                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1455                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1456                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1457                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1458                                   depth);
1459                                 return -EFSCORRUPTED;
1460                         }
1461                 }
1462                 return 0;
1463         }
1464
1465         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1466                 EXT4_ERROR_INODE(inode,
1467                                  "logical %d < ee_block %d + ee_len %d!",
1468                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1469                 return -EFSCORRUPTED;
1470         }
1471
1472         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1473         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1474         return 0;
1475 }
1476
1477 /*
1478  * search the closest allocated block to the right for *logical
1479  * and returns it at @logical + it's physical address at @phys
1480  * if *logical is the largest allocated block, the function
1481  * returns 0 at @phys
1482  * return value contains 0 (success) or error code
1483  */
1484 static int ext4_ext_search_right(struct inode *inode,
1485                                  struct ext4_ext_path *path,
1486                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1487                                  struct ext4_extent **ret_ex)
1488 {
1489         struct buffer_head *bh = NULL;
1490         struct ext4_extent_header *eh;
1491         struct ext4_extent_idx *ix;
1492         struct ext4_extent *ex;
1493         ext4_fsblk_t block;
1494         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1495         int ee_len;
1496
1497         if (unlikely(path == NULL)) {
1498                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1499                 return -EFSCORRUPTED;
1500         }
1501         depth = path->p_depth;
1502         *phys = 0;
1503
1504         if (depth == 0 && path->p_ext == NULL)
1505                 return 0;
1506
1507         /* usually extent in the path covers blocks smaller
1508          * then *logical, but it can be that extent is the
1509          * first one in the file */
1510
1511         ex = path[depth].p_ext;
1512         ee_len = ext4_ext_get_actual_len(ex);
1513         if (*logical < le32_to_cpu(ex->ee_block)) {
1514                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1515                         EXT4_ERROR_INODE(inode,
1516                                          "first_extent(path[%d].p_hdr) != ex",
1517                                          depth);
1518                         return -EFSCORRUPTED;
1519                 }
1520                 while (--depth >= 0) {
1521                         ix = path[depth].p_idx;
1522                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1523                                 EXT4_ERROR_INODE(inode,
1524                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1525                                                  *logical);
1526                                 return -EFSCORRUPTED;
1527                         }
1528                 }
1529                 goto found_extent;
1530         }
1531
1532         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1533                 EXT4_ERROR_INODE(inode,
1534                                  "logical %d < ee_block %d + ee_len %d!",
1535                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1536                 return -EFSCORRUPTED;
1537         }
1538
1539         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1540                 /* next allocated block in this leaf */
1541                 ex++;
1542                 goto found_extent;
1543         }
1544
1545         /* go up and search for index to the right */
1546         while (--depth >= 0) {
1547                 ix = path[depth].p_idx;
1548                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1549                         goto got_index;
1550         }
1551
1552         /* we've gone up to the root and found no index to the right */
1553         return 0;
1554
1555 got_index:
1556         /* we've found index to the right, let's
1557          * follow it and find the closest allocated
1558          * block to the right */
1559         ix++;
1560         block = ext4_idx_pblock(ix);
1561         while (++depth < path->p_depth) {
1562                 /* subtract from p_depth to get proper eh_depth */
1563                 bh = read_extent_tree_block(inode, block,
1564                                             path->p_depth - depth, 0);
1565                 if (IS_ERR(bh))
1566                         return PTR_ERR(bh);
1567                 eh = ext_block_hdr(bh);
1568                 ix = EXT_FIRST_INDEX(eh);
1569                 block = ext4_idx_pblock(ix);
1570                 put_bh(bh);
1571         }
1572
1573         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1574         if (IS_ERR(bh))
1575                 return PTR_ERR(bh);
1576         eh = ext_block_hdr(bh);
1577         ex = EXT_FIRST_EXTENT(eh);
1578 found_extent:
1579         *logical = le32_to_cpu(ex->ee_block);
1580         *phys = ext4_ext_pblock(ex);
1581         *ret_ex = ex;
1582         if (bh)
1583                 put_bh(bh);
1584         return 0;
1585 }
1586
1587 /*
1588  * ext4_ext_next_allocated_block:
1589  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1590  * NOTE: it considers block number from index entry as
1591  * allocated block. Thus, index entries have to be consistent
1592  * with leaves.
1593  */
1594 ext4_lblk_t
1595 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1596 {
1597         int depth;
1598
1599         BUG_ON(path == NULL);
1600         depth = path->p_depth;
1601
1602         if (depth == 0 && path->p_ext == NULL)
1603                 return EXT_MAX_BLOCKS;
1604
1605         while (depth >= 0) {
1606                 if (depth == path->p_depth) {
1607                         /* leaf */
1608                         if (path[depth].p_ext &&
1609                                 path[depth].p_ext !=
1610                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1611                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1612                 } else {
1613                         /* index */
1614                         if (path[depth].p_idx !=
1615                                         EXT_LAST_INDEX(path[depth].p_hdr))
1616                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1617                 }
1618                 depth--;
1619         }
1620
1621         return EXT_MAX_BLOCKS;
1622 }
1623
1624 /*
1625  * ext4_ext_next_leaf_block:
1626  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1627  */
1628 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1629 {
1630         int depth;
1631
1632         BUG_ON(path == NULL);
1633         depth = path->p_depth;
1634
1635         /* zero-tree has no leaf blocks at all */
1636         if (depth == 0)
1637                 return EXT_MAX_BLOCKS;
1638
1639         /* go to index block */
1640         depth--;
1641
1642         while (depth >= 0) {
1643                 if (path[depth].p_idx !=
1644                                 EXT_LAST_INDEX(path[depth].p_hdr))
1645                         return (ext4_lblk_t)
1646                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1647                 depth--;
1648         }
1649
1650         return EXT_MAX_BLOCKS;
1651 }
1652
1653 /*
1654  * ext4_ext_correct_indexes:
1655  * if leaf gets modified and modified extent is first in the leaf,
1656  * then we have to correct all indexes above.
1657  * TODO: do we need to correct tree in all cases?
1658  */
1659 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1660                                 struct ext4_ext_path *path)
1661 {
1662         struct ext4_extent_header *eh;
1663         int depth = ext_depth(inode);
1664         struct ext4_extent *ex;
1665         __le32 border;
1666         int k, err = 0;
1667
1668         eh = path[depth].p_hdr;
1669         ex = path[depth].p_ext;
1670
1671         if (unlikely(ex == NULL || eh == NULL)) {
1672                 EXT4_ERROR_INODE(inode,
1673                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1674                 return -EFSCORRUPTED;
1675         }
1676
1677         if (depth == 0) {
1678                 /* there is no tree at all */
1679                 return 0;
1680         }
1681
1682         if (ex != EXT_FIRST_EXTENT(eh)) {
1683                 /* we correct tree if first leaf got modified only */
1684                 return 0;
1685         }
1686
1687         /*
1688          * TODO: we need correction if border is smaller than current one
1689          */
1690         k = depth - 1;
1691         border = path[depth].p_ext->ee_block;
1692         err = ext4_ext_get_access(handle, inode, path + k);
1693         if (err)
1694                 return err;
1695         path[k].p_idx->ei_block = border;
1696         err = ext4_ext_dirty(handle, inode, path + k);
1697         if (err)
1698                 return err;
1699
1700         while (k--) {
1701                 /* change all left-side indexes */
1702                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1703                         break;
1704                 err = ext4_ext_get_access(handle, inode, path + k);
1705                 if (err)
1706                         break;
1707                 path[k].p_idx->ei_block = border;
1708                 err = ext4_ext_dirty(handle, inode, path + k);
1709                 if (err)
1710                         break;
1711         }
1712
1713         return err;
1714 }
1715
1716 int
1717 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1718                                 struct ext4_extent *ex2)
1719 {
1720         unsigned short ext1_ee_len, ext2_ee_len;
1721
1722         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1723                 return 0;
1724
1725         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1726         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1727
1728         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1729                         le32_to_cpu(ex2->ee_block))
1730                 return 0;
1731
1732         /*
1733          * To allow future support for preallocated extents to be added
1734          * as an RO_COMPAT feature, refuse to merge to extents if
1735          * this can result in the top bit of ee_len being set.
1736          */
1737         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1738                 return 0;
1739         /*
1740          * The check for IO to unwritten extent is somewhat racy as we
1741          * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after
1742          * dropping i_data_sem. But reserved blocks should save us in that
1743          * case.
1744          */
1745         if (ext4_ext_is_unwritten(ex1) &&
1746             (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1747              atomic_read(&EXT4_I(inode)->i_unwritten) ||
1748              (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1749                 return 0;
1750 #ifdef AGGRESSIVE_TEST
1751         if (ext1_ee_len >= 4)
1752                 return 0;
1753 #endif
1754
1755         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1756                 return 1;
1757         return 0;
1758 }
1759
1760 /*
1761  * This function tries to merge the "ex" extent to the next extent in the tree.
1762  * It always tries to merge towards right. If you want to merge towards
1763  * left, pass "ex - 1" as argument instead of "ex".
1764  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1765  * 1 if they got merged.
1766  */
1767 static int ext4_ext_try_to_merge_right(struct inode *inode,
1768                                  struct ext4_ext_path *path,
1769                                  struct ext4_extent *ex)
1770 {
1771         struct ext4_extent_header *eh;
1772         unsigned int depth, len;
1773         int merge_done = 0, unwritten;
1774
1775         depth = ext_depth(inode);
1776         BUG_ON(path[depth].p_hdr == NULL);
1777         eh = path[depth].p_hdr;
1778
1779         while (ex < EXT_LAST_EXTENT(eh)) {
1780                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1781                         break;
1782                 /* merge with next extent! */
1783                 unwritten = ext4_ext_is_unwritten(ex);
1784                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1785                                 + ext4_ext_get_actual_len(ex + 1));
1786                 if (unwritten)
1787                         ext4_ext_mark_unwritten(ex);
1788
1789                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1790                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1791                                 * sizeof(struct ext4_extent);
1792                         memmove(ex + 1, ex + 2, len);
1793                 }
1794                 le16_add_cpu(&eh->eh_entries, -1);
1795                 merge_done = 1;
1796                 WARN_ON(eh->eh_entries == 0);
1797                 if (!eh->eh_entries)
1798                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1799         }
1800
1801         return merge_done;
1802 }
1803
1804 /*
1805  * This function does a very simple check to see if we can collapse
1806  * an extent tree with a single extent tree leaf block into the inode.
1807  */
1808 static void ext4_ext_try_to_merge_up(handle_t *handle,
1809                                      struct inode *inode,
1810                                      struct ext4_ext_path *path)
1811 {
1812         size_t s;
1813         unsigned max_root = ext4_ext_space_root(inode, 0);
1814         ext4_fsblk_t blk;
1815
1816         if ((path[0].p_depth != 1) ||
1817             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1818             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1819                 return;
1820
1821         /*
1822          * We need to modify the block allocation bitmap and the block
1823          * group descriptor to release the extent tree block.  If we
1824          * can't get the journal credits, give up.
1825          */
1826         if (ext4_journal_extend(handle, 2))
1827                 return;
1828
1829         /*
1830          * Copy the extent data up to the inode
1831          */
1832         blk = ext4_idx_pblock(path[0].p_idx);
1833         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1834                 sizeof(struct ext4_extent_idx);
1835         s += sizeof(struct ext4_extent_header);
1836
1837         path[1].p_maxdepth = path[0].p_maxdepth;
1838         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1839         path[0].p_depth = 0;
1840         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1841                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1842         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1843
1844         brelse(path[1].p_bh);
1845         ext4_free_blocks(handle, inode, NULL, blk, 1,
1846                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1847 }
1848
1849 /*
1850  * This function tries to merge the @ex extent to neighbours in the tree.
1851  * return 1 if merge left else 0.
1852  */
1853 static void ext4_ext_try_to_merge(handle_t *handle,
1854                                   struct inode *inode,
1855                                   struct ext4_ext_path *path,
1856                                   struct ext4_extent *ex) {
1857         struct ext4_extent_header *eh;
1858         unsigned int depth;
1859         int merge_done = 0;
1860
1861         depth = ext_depth(inode);
1862         BUG_ON(path[depth].p_hdr == NULL);
1863         eh = path[depth].p_hdr;
1864
1865         if (ex > EXT_FIRST_EXTENT(eh))
1866                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1867
1868         if (!merge_done)
1869                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1870
1871         ext4_ext_try_to_merge_up(handle, inode, path);
1872 }
1873
1874 /*
1875  * check if a portion of the "newext" extent overlaps with an
1876  * existing extent.
1877  *
1878  * If there is an overlap discovered, it updates the length of the newext
1879  * such that there will be no overlap, and then returns 1.
1880  * If there is no overlap found, it returns 0.
1881  */
1882 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1883                                            struct inode *inode,
1884                                            struct ext4_extent *newext,
1885                                            struct ext4_ext_path *path)
1886 {
1887         ext4_lblk_t b1, b2;
1888         unsigned int depth, len1;
1889         unsigned int ret = 0;
1890
1891         b1 = le32_to_cpu(newext->ee_block);
1892         len1 = ext4_ext_get_actual_len(newext);
1893         depth = ext_depth(inode);
1894         if (!path[depth].p_ext)
1895                 goto out;
1896         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1897
1898         /*
1899          * get the next allocated block if the extent in the path
1900          * is before the requested block(s)
1901          */
1902         if (b2 < b1) {
1903                 b2 = ext4_ext_next_allocated_block(path);
1904                 if (b2 == EXT_MAX_BLOCKS)
1905                         goto out;
1906                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1907         }
1908
1909         /* check for wrap through zero on extent logical start block*/
1910         if (b1 + len1 < b1) {
1911                 len1 = EXT_MAX_BLOCKS - b1;
1912                 newext->ee_len = cpu_to_le16(len1);
1913                 ret = 1;
1914         }
1915
1916         /* check for overlap */
1917         if (b1 + len1 > b2) {
1918                 newext->ee_len = cpu_to_le16(b2 - b1);
1919                 ret = 1;
1920         }
1921 out:
1922         return ret;
1923 }
1924
1925 /*
1926  * ext4_ext_insert_extent:
1927  * tries to merge requsted extent into the existing extent or
1928  * inserts requested extent as new one into the tree,
1929  * creating new leaf in the no-space case.
1930  */
1931 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1932                                 struct ext4_ext_path **ppath,
1933                                 struct ext4_extent *newext, int gb_flags)
1934 {
1935         struct ext4_ext_path *path = *ppath;
1936         struct ext4_extent_header *eh;
1937         struct ext4_extent *ex, *fex;
1938         struct ext4_extent *nearex; /* nearest extent */
1939         struct ext4_ext_path *npath = NULL;
1940         int depth, len, err;
1941         ext4_lblk_t next;
1942         int mb_flags = 0, unwritten;
1943
1944         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1945                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1946         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1947                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1948                 return -EFSCORRUPTED;
1949         }
1950         depth = ext_depth(inode);
1951         ex = path[depth].p_ext;
1952         eh = path[depth].p_hdr;
1953         if (unlikely(path[depth].p_hdr == NULL)) {
1954                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1955                 return -EFSCORRUPTED;
1956         }
1957
1958         /* try to insert block into found extent and return */
1959         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1960
1961                 /*
1962                  * Try to see whether we should rather test the extent on
1963                  * right from ex, or from the left of ex. This is because
1964                  * ext4_find_extent() can return either extent on the
1965                  * left, or on the right from the searched position. This
1966                  * will make merging more effective.
1967                  */
1968                 if (ex < EXT_LAST_EXTENT(eh) &&
1969                     (le32_to_cpu(ex->ee_block) +
1970                     ext4_ext_get_actual_len(ex) <
1971                     le32_to_cpu(newext->ee_block))) {
1972                         ex += 1;
1973                         goto prepend;
1974                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1975                            (le32_to_cpu(newext->ee_block) +
1976                            ext4_ext_get_actual_len(newext) <
1977                            le32_to_cpu(ex->ee_block)))
1978                         ex -= 1;
1979
1980                 /* Try to append newex to the ex */
1981                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1982                         ext_debug("append [%d]%d block to %u:[%d]%d"
1983                                   "(from %llu)\n",
1984                                   ext4_ext_is_unwritten(newext),
1985                                   ext4_ext_get_actual_len(newext),
1986                                   le32_to_cpu(ex->ee_block),
1987                                   ext4_ext_is_unwritten(ex),
1988                                   ext4_ext_get_actual_len(ex),
1989                                   ext4_ext_pblock(ex));
1990                         err = ext4_ext_get_access(handle, inode,
1991                                                   path + depth);
1992                         if (err)
1993                                 return err;
1994                         unwritten = ext4_ext_is_unwritten(ex);
1995                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1996                                         + ext4_ext_get_actual_len(newext));
1997                         if (unwritten)
1998                                 ext4_ext_mark_unwritten(ex);
1999                         eh = path[depth].p_hdr;
2000                         nearex = ex;
2001                         goto merge;
2002                 }
2003
2004 prepend:
2005                 /* Try to prepend newex to the ex */
2006                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2007                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2008                                   "(from %llu)\n",
2009                                   le32_to_cpu(newext->ee_block),
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
2021                         unwritten = ext4_ext_is_unwritten(ex);
2022                         ex->ee_block = newext->ee_block;
2023                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2024                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2025                                         + ext4_ext_get_actual_len(newext));
2026                         if (unwritten)
2027                                 ext4_ext_mark_unwritten(ex);
2028                         eh = path[depth].p_hdr;
2029                         nearex = ex;
2030                         goto merge;
2031                 }
2032         }
2033
2034         depth = ext_depth(inode);
2035         eh = path[depth].p_hdr;
2036         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2037                 goto has_space;
2038
2039         /* probably next leaf has space for us? */
2040         fex = EXT_LAST_EXTENT(eh);
2041         next = EXT_MAX_BLOCKS;
2042         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2043                 next = ext4_ext_next_leaf_block(path);
2044         if (next != EXT_MAX_BLOCKS) {
2045                 ext_debug("next leaf block - %u\n", next);
2046                 BUG_ON(npath != NULL);
2047                 npath = ext4_find_extent(inode, next, NULL, 0);
2048                 if (IS_ERR(npath))
2049                         return PTR_ERR(npath);
2050                 BUG_ON(npath->p_depth != path->p_depth);
2051                 eh = npath[depth].p_hdr;
2052                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2053                         ext_debug("next leaf isn't full(%d)\n",
2054                                   le16_to_cpu(eh->eh_entries));
2055                         path = npath;
2056                         goto has_space;
2057                 }
2058                 ext_debug("next leaf has no free space(%d,%d)\n",
2059                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2060         }
2061
2062         /*
2063          * There is no free space in the found leaf.
2064          * We're gonna add a new leaf in the tree.
2065          */
2066         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2067                 mb_flags |= EXT4_MB_USE_RESERVED;
2068         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2069                                        ppath, newext);
2070         if (err)
2071                 goto cleanup;
2072         depth = ext_depth(inode);
2073         eh = path[depth].p_hdr;
2074
2075 has_space:
2076         nearex = path[depth].p_ext;
2077
2078         err = ext4_ext_get_access(handle, inode, path + depth);
2079         if (err)
2080                 goto cleanup;
2081
2082         if (!nearex) {
2083                 /* there is no extent in this leaf, create first one */
2084                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2085                                 le32_to_cpu(newext->ee_block),
2086                                 ext4_ext_pblock(newext),
2087                                 ext4_ext_is_unwritten(newext),
2088                                 ext4_ext_get_actual_len(newext));
2089                 nearex = EXT_FIRST_EXTENT(eh);
2090         } else {
2091                 if (le32_to_cpu(newext->ee_block)
2092                            > le32_to_cpu(nearex->ee_block)) {
2093                         /* Insert after */
2094                         ext_debug("insert %u:%llu:[%d]%d before: "
2095                                         "nearest %p\n",
2096                                         le32_to_cpu(newext->ee_block),
2097                                         ext4_ext_pblock(newext),
2098                                         ext4_ext_is_unwritten(newext),
2099                                         ext4_ext_get_actual_len(newext),
2100                                         nearex);
2101                         nearex++;
2102                 } else {
2103                         /* Insert before */
2104                         BUG_ON(newext->ee_block == nearex->ee_block);
2105                         ext_debug("insert %u:%llu:[%d]%d after: "
2106                                         "nearest %p\n",
2107                                         le32_to_cpu(newext->ee_block),
2108                                         ext4_ext_pblock(newext),
2109                                         ext4_ext_is_unwritten(newext),
2110                                         ext4_ext_get_actual_len(newext),
2111                                         nearex);
2112                 }
2113                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2114                 if (len > 0) {
2115                         ext_debug("insert %u:%llu:[%d]%d: "
2116                                         "move %d extents from 0x%p to 0x%p\n",
2117                                         le32_to_cpu(newext->ee_block),
2118                                         ext4_ext_pblock(newext),
2119                                         ext4_ext_is_unwritten(newext),
2120                                         ext4_ext_get_actual_len(newext),
2121                                         len, nearex, nearex + 1);
2122                         memmove(nearex + 1, nearex,
2123                                 len * sizeof(struct ext4_extent));
2124                 }
2125         }
2126
2127         le16_add_cpu(&eh->eh_entries, 1);
2128         path[depth].p_ext = nearex;
2129         nearex->ee_block = newext->ee_block;
2130         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2131         nearex->ee_len = newext->ee_len;
2132
2133 merge:
2134         /* try to merge extents */
2135         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2136                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2137
2138
2139         /* time to correct all indexes above */
2140         err = ext4_ext_correct_indexes(handle, inode, path);
2141         if (err)
2142                 goto cleanup;
2143
2144         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2145
2146 cleanup:
2147         ext4_ext_drop_refs(npath);
2148         kfree(npath);
2149         return err;
2150 }
2151
2152 static int ext4_fill_fiemap_extents(struct inode *inode,
2153                                     ext4_lblk_t block, ext4_lblk_t num,
2154                                     struct fiemap_extent_info *fieinfo)
2155 {
2156         struct ext4_ext_path *path = NULL;
2157         struct ext4_extent *ex;
2158         struct extent_status es;
2159         ext4_lblk_t next, next_del, start = 0, end = 0;
2160         ext4_lblk_t last = block + num;
2161         int exists, depth = 0, err = 0;
2162         unsigned int flags = 0;
2163         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2164
2165         while (block < last && block != EXT_MAX_BLOCKS) {
2166                 num = last - block;
2167                 /* find extent for this block */
2168                 down_read(&EXT4_I(inode)->i_data_sem);
2169
2170                 path = ext4_find_extent(inode, block, &path, 0);
2171                 if (IS_ERR(path)) {
2172                         up_read(&EXT4_I(inode)->i_data_sem);
2173                         err = PTR_ERR(path);
2174                         path = NULL;
2175                         break;
2176                 }
2177
2178                 depth = ext_depth(inode);
2179                 if (unlikely(path[depth].p_hdr == NULL)) {
2180                         up_read(&EXT4_I(inode)->i_data_sem);
2181                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2182                         err = -EFSCORRUPTED;
2183                         break;
2184                 }
2185                 ex = path[depth].p_ext;
2186                 next = ext4_ext_next_allocated_block(path);
2187
2188                 flags = 0;
2189                 exists = 0;
2190                 if (!ex) {
2191                         /* there is no extent yet, so try to allocate
2192                          * all requested space */
2193                         start = block;
2194                         end = block + num;
2195                 } else if (le32_to_cpu(ex->ee_block) > block) {
2196                         /* need to allocate space before found extent */
2197                         start = block;
2198                         end = le32_to_cpu(ex->ee_block);
2199                         if (block + num < end)
2200                                 end = block + num;
2201                 } else if (block >= le32_to_cpu(ex->ee_block)
2202                                         + ext4_ext_get_actual_len(ex)) {
2203                         /* need to allocate space after found extent */
2204                         start = block;
2205                         end = block + num;
2206                         if (end >= next)
2207                                 end = next;
2208                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2209                         /*
2210                          * some part of requested space is covered
2211                          * by found extent
2212                          */
2213                         start = block;
2214                         end = le32_to_cpu(ex->ee_block)
2215                                 + ext4_ext_get_actual_len(ex);
2216                         if (block + num < end)
2217                                 end = block + num;
2218                         exists = 1;
2219                 } else {
2220                         BUG();
2221                 }
2222                 BUG_ON(end <= start);
2223
2224                 if (!exists) {
2225                         es.es_lblk = start;
2226                         es.es_len = end - start;
2227                         es.es_pblk = 0;
2228                 } else {
2229                         es.es_lblk = le32_to_cpu(ex->ee_block);
2230                         es.es_len = ext4_ext_get_actual_len(ex);
2231                         es.es_pblk = ext4_ext_pblock(ex);
2232                         if (ext4_ext_is_unwritten(ex))
2233                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2234                 }
2235
2236                 /*
2237                  * Find delayed extent and update es accordingly. We call
2238                  * it even in !exists case to find out whether es is the
2239                  * last existing extent or not.
2240                  */
2241                 next_del = ext4_find_delayed_extent(inode, &es);
2242                 if (!exists && next_del) {
2243                         exists = 1;
2244                         flags |= (FIEMAP_EXTENT_DELALLOC |
2245                                   FIEMAP_EXTENT_UNKNOWN);
2246                 }
2247                 up_read(&EXT4_I(inode)->i_data_sem);
2248
2249                 if (unlikely(es.es_len == 0)) {
2250                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2251                         err = -EFSCORRUPTED;
2252                         break;
2253                 }
2254
2255                 /*
2256                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2257                  * we need to check next == EXT_MAX_BLOCKS because it is
2258                  * possible that an extent is with unwritten and delayed
2259                  * status due to when an extent is delayed allocated and
2260                  * is allocated by fallocate status tree will track both of
2261                  * them in a extent.
2262                  *
2263                  * So we could return a unwritten and delayed extent, and
2264                  * its block is equal to 'next'.
2265                  */
2266                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2267                         flags |= FIEMAP_EXTENT_LAST;
2268                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2269                                      next != EXT_MAX_BLOCKS)) {
2270                                 EXT4_ERROR_INODE(inode,
2271                                                  "next extent == %u, next "
2272                                                  "delalloc extent = %u",
2273                                                  next, next_del);
2274                                 err = -EFSCORRUPTED;
2275                                 break;
2276                         }
2277                 }
2278
2279                 if (exists) {
2280                         err = fiemap_fill_next_extent(fieinfo,
2281                                 (__u64)es.es_lblk << blksize_bits,
2282                                 (__u64)es.es_pblk << blksize_bits,
2283                                 (__u64)es.es_len << blksize_bits,
2284                                 flags);
2285                         if (err < 0)
2286                                 break;
2287                         if (err == 1) {
2288                                 err = 0;
2289                                 break;
2290                         }
2291                 }
2292
2293                 block = es.es_lblk + es.es_len;
2294         }
2295
2296         ext4_ext_drop_refs(path);
2297         kfree(path);
2298         return err;
2299 }
2300
2301 /*
2302  * ext4_ext_determine_hole - determine hole around given block
2303  * @inode:      inode we lookup in
2304  * @path:       path in extent tree to @lblk
2305  * @lblk:       pointer to logical block around which we want to determine hole
2306  *
2307  * Determine hole length (and start if easily possible) around given logical
2308  * block. We don't try too hard to find the beginning of the hole but @path
2309  * actually points to extent before @lblk, we provide it.
2310  *
2311  * The function returns the length of a hole starting at @lblk. We update @lblk
2312  * to the beginning of the hole if we managed to find it.
2313  */
2314 static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2315                                            struct ext4_ext_path *path,
2316                                            ext4_lblk_t *lblk)
2317 {
2318         int depth = ext_depth(inode);
2319         struct ext4_extent *ex;
2320         ext4_lblk_t len;
2321
2322         ex = path[depth].p_ext;
2323         if (ex == NULL) {
2324                 /* there is no extent yet, so gap is [0;-] */
2325                 *lblk = 0;
2326                 len = EXT_MAX_BLOCKS;
2327         } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2328                 len = le32_to_cpu(ex->ee_block) - *lblk;
2329         } else if (*lblk >= le32_to_cpu(ex->ee_block)
2330                         + ext4_ext_get_actual_len(ex)) {
2331                 ext4_lblk_t next;
2332
2333                 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2334                 next = ext4_ext_next_allocated_block(path);
2335                 BUG_ON(next == *lblk);
2336                 len = next - *lblk;
2337         } else {
2338                 BUG();
2339         }
2340         return len;
2341 }
2342
2343 /*
2344  * ext4_ext_put_gap_in_cache:
2345  * calculate boundaries of the gap that the requested block fits into
2346  * and cache this gap
2347  */
2348 static void
2349 ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2350                           ext4_lblk_t hole_len)
2351 {
2352         struct extent_status es;
2353
2354         ext4_es_find_delayed_extent_range(inode, hole_start,
2355                                           hole_start + hole_len - 1, &es);
2356         if (es.es_len) {
2357                 /* There's delayed extent containing lblock? */
2358                 if (es.es_lblk <= hole_start)
2359                         return;
2360                 hole_len = min(es.es_lblk - hole_start, hole_len);
2361         }
2362         ext_debug(" -> %u:%u\n", hole_start, hole_len);
2363         ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2364                               EXTENT_STATUS_HOLE);
2365 }
2366
2367 /*
2368  * ext4_ext_rm_idx:
2369  * removes index from the index block.
2370  */
2371 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2372                         struct ext4_ext_path *path, int depth)
2373 {
2374         int err;
2375         ext4_fsblk_t leaf;
2376
2377         /* free index block */
2378         depth--;
2379         path = path + depth;
2380         leaf = ext4_idx_pblock(path->p_idx);
2381         if (unlikely(path->p_hdr->eh_entries == 0)) {
2382                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2383                 return -EFSCORRUPTED;
2384         }
2385         err = ext4_ext_get_access(handle, inode, path);
2386         if (err)
2387                 return err;
2388
2389         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2390                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2391                 len *= sizeof(struct ext4_extent_idx);
2392                 memmove(path->p_idx, path->p_idx + 1, len);
2393         }
2394
2395         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2396         err = ext4_ext_dirty(handle, inode, path);
2397         if (err)
2398                 return err;
2399         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2400         trace_ext4_ext_rm_idx(inode, leaf);
2401
2402         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2403                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2404
2405         while (--depth >= 0) {
2406                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2407                         break;
2408                 path--;
2409                 err = ext4_ext_get_access(handle, inode, path);
2410                 if (err)
2411                         break;
2412                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2413                 err = ext4_ext_dirty(handle, inode, path);
2414                 if (err)
2415                         break;
2416         }
2417         return err;
2418 }
2419
2420 /*
2421  * ext4_ext_calc_credits_for_single_extent:
2422  * This routine returns max. credits that needed to insert an extent
2423  * to the extent tree.
2424  * When pass the actual path, the caller should calculate credits
2425  * under i_data_sem.
2426  */
2427 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2428                                                 struct ext4_ext_path *path)
2429 {
2430         if (path) {
2431                 int depth = ext_depth(inode);
2432                 int ret = 0;
2433
2434                 /* probably there is space in leaf? */
2435                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2436                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2437
2438                         /*
2439                          *  There are some space in the leaf tree, no
2440                          *  need to account for leaf block credit
2441                          *
2442                          *  bitmaps and block group descriptor blocks
2443                          *  and other metadata blocks still need to be
2444                          *  accounted.
2445                          */
2446                         /* 1 bitmap, 1 block group descriptor */
2447                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2448                         return ret;
2449                 }
2450         }
2451
2452         return ext4_chunk_trans_blocks(inode, nrblocks);
2453 }
2454
2455 /*
2456  * How many index/leaf blocks need to change/allocate to add @extents extents?
2457  *
2458  * If we add a single extent, then in the worse case, each tree level
2459  * index/leaf need to be changed in case of the tree split.
2460  *
2461  * If more extents are inserted, they could cause the whole tree split more
2462  * than once, but this is really rare.
2463  */
2464 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2465 {
2466         int index;
2467         int depth;
2468
2469         /* If we are converting the inline data, only one is needed here. */
2470         if (ext4_has_inline_data(inode))
2471                 return 1;
2472
2473         depth = ext_depth(inode);
2474
2475         if (extents <= 1)
2476                 index = depth * 2;
2477         else
2478                 index = depth * 3;
2479
2480         return index;
2481 }
2482
2483 static inline int get_default_free_blocks_flags(struct inode *inode)
2484 {
2485         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2486                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2487         else if (ext4_should_journal_data(inode))
2488                 return EXT4_FREE_BLOCKS_FORGET;
2489         return 0;
2490 }
2491
2492 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2493                               struct ext4_extent *ex,
2494                               long long *partial_cluster,
2495                               ext4_lblk_t from, ext4_lblk_t to)
2496 {
2497         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2498         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2499         ext4_fsblk_t pblk;
2500         int flags = get_default_free_blocks_flags(inode);
2501
2502         /*
2503          * For bigalloc file systems, we never free a partial cluster
2504          * at the beginning of the extent.  Instead, we make a note
2505          * that we tried freeing the cluster, and check to see if we
2506          * need to free it on a subsequent call to ext4_remove_blocks,
2507          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2508          */
2509         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2510
2511         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2512         /*
2513          * If we have a partial cluster, and it's different from the
2514          * cluster of the last block, we need to explicitly free the
2515          * partial cluster here.
2516          */
2517         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2518         if (*partial_cluster > 0 &&
2519             *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2520                 ext4_free_blocks(handle, inode, NULL,
2521                                  EXT4_C2B(sbi, *partial_cluster),
2522                                  sbi->s_cluster_ratio, flags);
2523                 *partial_cluster = 0;
2524         }
2525
2526 #ifdef EXTENTS_STATS
2527         {
2528                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2529                 spin_lock(&sbi->s_ext_stats_lock);
2530                 sbi->s_ext_blocks += ee_len;
2531                 sbi->s_ext_extents++;
2532                 if (ee_len < sbi->s_ext_min)
2533                         sbi->s_ext_min = ee_len;
2534                 if (ee_len > sbi->s_ext_max)
2535                         sbi->s_ext_max = ee_len;
2536                 if (ext_depth(inode) > sbi->s_depth_max)
2537                         sbi->s_depth_max = ext_depth(inode);
2538                 spin_unlock(&sbi->s_ext_stats_lock);
2539         }
2540 #endif
2541         if (from >= le32_to_cpu(ex->ee_block)
2542             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2543                 /* tail removal */
2544                 ext4_lblk_t num;
2545                 long long first_cluster;
2546
2547                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2548                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2549                 /*
2550                  * Usually we want to free partial cluster at the end of the
2551                  * extent, except for the situation when the cluster is still
2552                  * used by any other extent (partial_cluster is negative).
2553                  */
2554                 if (*partial_cluster < 0 &&
2555                     *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))
2556                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2557
2558                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2559                           num, pblk, *partial_cluster);
2560                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2561                 /*
2562                  * If the block range to be freed didn't start at the
2563                  * beginning of a cluster, and we removed the entire
2564                  * extent and the cluster is not used by any other extent,
2565                  * save the partial cluster here, since we might need to
2566                  * delete if we determine that the truncate or punch hole
2567                  * operation has removed all of the blocks in the cluster.
2568                  * If that cluster is used by another extent, preserve its
2569                  * negative value so it isn't freed later on.
2570                  *
2571                  * If the whole extent wasn't freed, we've reached the
2572                  * start of the truncated/punched region and have finished
2573                  * removing blocks.  If there's a partial cluster here it's
2574                  * shared with the remainder of the extent and is no longer
2575                  * a candidate for removal.
2576                  */
2577                 if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {
2578                         first_cluster = (long long) EXT4_B2C(sbi, pblk);
2579                         if (first_cluster != -*partial_cluster)
2580                                 *partial_cluster = first_cluster;
2581                 } else {
2582                         *partial_cluster = 0;
2583                 }
2584         } else
2585                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2586                            "%u-%u from %u:%u\n",
2587                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2588         return 0;
2589 }
2590
2591
2592 /*
2593  * ext4_ext_rm_leaf() Removes the extents associated with the
2594  * blocks appearing between "start" and "end".  Both "start"
2595  * and "end" must appear in the same extent or EIO is returned.
2596  *
2597  * @handle: The journal handle
2598  * @inode:  The files inode
2599  * @path:   The path to the leaf
2600  * @partial_cluster: The cluster which we'll have to free if all extents
2601  *                   has been released from it.  However, if this value is
2602  *                   negative, it's a cluster just to the right of the
2603  *                   punched region and it must not be freed.
2604  * @start:  The first block to remove
2605  * @end:   The last block to remove
2606  */
2607 static int
2608 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2609                  struct ext4_ext_path *path,
2610                  long long *partial_cluster,
2611                  ext4_lblk_t start, ext4_lblk_t end)
2612 {
2613         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2614         int err = 0, correct_index = 0;
2615         int depth = ext_depth(inode), credits;
2616         struct ext4_extent_header *eh;
2617         ext4_lblk_t a, b;
2618         unsigned num;
2619         ext4_lblk_t ex_ee_block;
2620         unsigned short ex_ee_len;
2621         unsigned unwritten = 0;
2622         struct ext4_extent *ex;
2623         ext4_fsblk_t pblk;
2624
2625         /* the header must be checked already in ext4_ext_remove_space() */
2626         ext_debug("truncate since %u in leaf to %u\n", start, end);
2627         if (!path[depth].p_hdr)
2628                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2629         eh = path[depth].p_hdr;
2630         if (unlikely(path[depth].p_hdr == NULL)) {
2631                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2632                 return -EFSCORRUPTED;
2633         }
2634         /* find where to start removing */
2635         ex = path[depth].p_ext;
2636         if (!ex)
2637                 ex = EXT_LAST_EXTENT(eh);
2638
2639         ex_ee_block = le32_to_cpu(ex->ee_block);
2640         ex_ee_len = ext4_ext_get_actual_len(ex);
2641
2642         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2643
2644         while (ex >= EXT_FIRST_EXTENT(eh) &&
2645                         ex_ee_block + ex_ee_len > start) {
2646
2647                 if (ext4_ext_is_unwritten(ex))
2648                         unwritten = 1;
2649                 else
2650                         unwritten = 0;
2651
2652                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2653                           unwritten, ex_ee_len);
2654                 path[depth].p_ext = ex;
2655
2656                 a = ex_ee_block > start ? ex_ee_block : start;
2657                 b = ex_ee_block+ex_ee_len - 1 < end ?
2658                         ex_ee_block+ex_ee_len - 1 : end;
2659
2660                 ext_debug("  border %u:%u\n", a, b);
2661
2662                 /* If this extent is beyond the end of the hole, skip it */
2663                 if (end < ex_ee_block) {
2664                         /*
2665                          * We're going to skip this extent and move to another,
2666                          * so note that its first cluster is in use to avoid
2667                          * freeing it when removing blocks.  Eventually, the
2668                          * right edge of the truncated/punched region will
2669                          * be just to the left.
2670                          */
2671                         if (sbi->s_cluster_ratio > 1) {
2672                                 pblk = ext4_ext_pblock(ex);
2673                                 *partial_cluster =
2674                                         -(long long) EXT4_B2C(sbi, pblk);
2675                         }
2676                         ex--;
2677                         ex_ee_block = le32_to_cpu(ex->ee_block);
2678                         ex_ee_len = ext4_ext_get_actual_len(ex);
2679                         continue;
2680                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2681                         EXT4_ERROR_INODE(inode,
2682                                          "can not handle truncate %u:%u "
2683                                          "on extent %u:%u",
2684                                          start, end, ex_ee_block,
2685                                          ex_ee_block + ex_ee_len - 1);
2686                         err = -EFSCORRUPTED;
2687                         goto out;
2688                 } else if (a != ex_ee_block) {
2689                         /* remove tail of the extent */
2690                         num = a - ex_ee_block;
2691                 } else {
2692                         /* remove whole extent: excellent! */
2693                         num = 0;
2694                 }
2695                 /*
2696                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2697                  * descriptor) for each block group; assume two block
2698                  * groups plus ex_ee_len/blocks_per_block_group for
2699                  * the worst case
2700                  */
2701                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2702                 if (ex == EXT_FIRST_EXTENT(eh)) {
2703                         correct_index = 1;
2704                         credits += (ext_depth(inode)) + 1;
2705                 }
2706                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2707
2708                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2709                 if (err)
2710                         goto out;
2711
2712                 err = ext4_ext_get_access(handle, inode, path + depth);
2713                 if (err)
2714                         goto out;
2715
2716                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2717                                          a, b);
2718                 if (err)
2719                         goto out;
2720
2721                 if (num == 0)
2722                         /* this extent is removed; mark slot entirely unused */
2723                         ext4_ext_store_pblock(ex, 0);
2724
2725                 ex->ee_len = cpu_to_le16(num);
2726                 /*
2727                  * Do not mark unwritten if all the blocks in the
2728                  * extent have been removed.
2729                  */
2730                 if (unwritten && num)
2731                         ext4_ext_mark_unwritten(ex);
2732                 /*
2733                  * If the extent was completely released,
2734                  * we need to remove it from the leaf
2735                  */
2736                 if (num == 0) {
2737                         if (end != EXT_MAX_BLOCKS - 1) {
2738                                 /*
2739                                  * For hole punching, we need to scoot all the
2740                                  * extents up when an extent is removed so that
2741                                  * we dont have blank extents in the middle
2742                                  */
2743                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2744                                         sizeof(struct ext4_extent));
2745
2746                                 /* Now get rid of the one at the end */
2747                                 memset(EXT_LAST_EXTENT(eh), 0,
2748                                         sizeof(struct ext4_extent));
2749                         }
2750                         le16_add_cpu(&eh->eh_entries, -1);
2751                 }
2752
2753                 err = ext4_ext_dirty(handle, inode, path + depth);
2754                 if (err)
2755                         goto out;
2756
2757                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2758                                 ext4_ext_pblock(ex));
2759                 ex--;
2760                 ex_ee_block = le32_to_cpu(ex->ee_block);
2761                 ex_ee_len = ext4_ext_get_actual_len(ex);
2762         }
2763
2764         if (correct_index && eh->eh_entries)
2765                 err = ext4_ext_correct_indexes(handle, inode, path);
2766
2767         /*
2768          * If there's a partial cluster and at least one extent remains in
2769          * the leaf, free the partial cluster if it isn't shared with the
2770          * current extent.  If it is shared with the current extent
2771          * we zero partial_cluster because we've reached the start of the
2772          * truncated/punched region and we're done removing blocks.
2773          */
2774         if (*partial_cluster > 0 && ex >= EXT_FIRST_EXTENT(eh)) {
2775                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2776                 if (*partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2777                         ext4_free_blocks(handle, inode, NULL,
2778                                          EXT4_C2B(sbi, *partial_cluster),
2779                                          sbi->s_cluster_ratio,
2780                                          get_default_free_blocks_flags(inode));
2781                 }
2782                 *partial_cluster = 0;
2783         }
2784
2785         /* if this leaf is free, then we should
2786          * remove it from index block above */
2787         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2788                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2789
2790 out:
2791         return err;
2792 }
2793
2794 /*
2795  * ext4_ext_more_to_rm:
2796  * returns 1 if current index has to be freed (even partial)
2797  */
2798 static int
2799 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2800 {
2801         BUG_ON(path->p_idx == NULL);
2802
2803         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2804                 return 0;
2805
2806         /*
2807          * if truncate on deeper level happened, it wasn't partial,
2808          * so we have to consider current index for truncation
2809          */
2810         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2811                 return 0;
2812         return 1;
2813 }
2814
2815 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2816                           ext4_lblk_t end)
2817 {
2818         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2819         int depth = ext_depth(inode);
2820         struct ext4_ext_path *path = NULL;
2821         long long partial_cluster = 0;
2822         handle_t *handle;
2823         int i = 0, err = 0;
2824
2825         ext_debug("truncate since %u to %u\n", start, end);
2826
2827         /* probably first extent we're gonna free will be last in block */
2828         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2829         if (IS_ERR(handle))
2830                 return PTR_ERR(handle);
2831
2832 again:
2833         trace_ext4_ext_remove_space(inode, start, end, depth);
2834
2835         /*
2836          * Check if we are removing extents inside the extent tree. If that
2837          * is the case, we are going to punch a hole inside the extent tree
2838          * so we have to check whether we need to split the extent covering
2839          * the last block to remove so we can easily remove the part of it
2840          * in ext4_ext_rm_leaf().
2841          */
2842         if (end < EXT_MAX_BLOCKS - 1) {
2843                 struct ext4_extent *ex;
2844                 ext4_lblk_t ee_block, ex_end, lblk;
2845                 ext4_fsblk_t pblk;
2846
2847                 /* find extent for or closest extent to this block */
2848                 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2849                 if (IS_ERR(path)) {
2850                         ext4_journal_stop(handle);
2851                         return PTR_ERR(path);
2852                 }
2853                 depth = ext_depth(inode);
2854                 /* Leaf not may not exist only if inode has no blocks at all */
2855                 ex = path[depth].p_ext;
2856                 if (!ex) {
2857                         if (depth) {
2858                                 EXT4_ERROR_INODE(inode,
2859                                                  "path[%d].p_hdr == NULL",
2860                                                  depth);
2861                                 err = -EFSCORRUPTED;
2862                         }
2863                         goto out;
2864                 }
2865
2866                 ee_block = le32_to_cpu(ex->ee_block);
2867                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2868
2869                 /*
2870                  * See if the last block is inside the extent, if so split
2871                  * the extent at 'end' block so we can easily remove the
2872                  * tail of the first part of the split extent in
2873                  * ext4_ext_rm_leaf().
2874                  */
2875                 if (end >= ee_block && end < ex_end) {
2876
2877                         /*
2878                          * If we're going to split the extent, note that
2879                          * the cluster containing the block after 'end' is
2880                          * in use to avoid freeing it when removing blocks.
2881                          */
2882                         if (sbi->s_cluster_ratio > 1) {
2883                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2884                                 partial_cluster =
2885                                         -(long long) EXT4_B2C(sbi, pblk);
2886                         }
2887
2888                         /*
2889                          * Split the extent in two so that 'end' is the last
2890                          * block in the first new extent. Also we should not
2891                          * fail removing space due to ENOSPC so try to use
2892                          * reserved block if that happens.
2893                          */
2894                         err = ext4_force_split_extent_at(handle, inode, &path,
2895                                                          end + 1, 1);
2896                         if (err < 0)
2897                                 goto out;
2898
2899                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end) {
2900                         /*
2901                          * If there's an extent to the right its first cluster
2902                          * contains the immediate right boundary of the
2903                          * truncated/punched region.  Set partial_cluster to
2904                          * its negative value so it won't be freed if shared
2905                          * with the current extent.  The end < ee_block case
2906                          * is handled in ext4_ext_rm_leaf().
2907                          */
2908                         lblk = ex_end + 1;
2909                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2910                                                     &ex);
2911                         if (err)
2912                                 goto out;
2913                         if (pblk)
2914                                 partial_cluster =
2915                                         -(long long) EXT4_B2C(sbi, pblk);
2916                 }
2917         }
2918         /*
2919          * We start scanning from right side, freeing all the blocks
2920          * after i_size and walking into the tree depth-wise.
2921          */
2922         depth = ext_depth(inode);
2923         if (path) {
2924                 int k = i = depth;
2925                 while (--k > 0)
2926                         path[k].p_block =
2927                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2928         } else {
2929                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2930                                GFP_NOFS);
2931                 if (path == NULL) {
2932                         ext4_journal_stop(handle);
2933                         return -ENOMEM;
2934                 }
2935                 path[0].p_maxdepth = path[0].p_depth = depth;
2936                 path[0].p_hdr = ext_inode_hdr(inode);
2937                 i = 0;
2938
2939                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2940                         err = -EFSCORRUPTED;
2941                         goto out;
2942                 }
2943         }
2944         err = 0;
2945
2946         while (i >= 0 && err == 0) {
2947                 if (i == depth) {
2948                         /* this is leaf block */
2949                         err = ext4_ext_rm_leaf(handle, inode, path,
2950                                                &partial_cluster, start,
2951                                                end);
2952                         /* root level has p_bh == NULL, brelse() eats this */
2953                         brelse(path[i].p_bh);
2954                         path[i].p_bh = NULL;
2955                         i--;
2956                         continue;
2957                 }
2958
2959                 /* this is index block */
2960                 if (!path[i].p_hdr) {
2961                         ext_debug("initialize header\n");
2962                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2963                 }
2964
2965                 if (!path[i].p_idx) {
2966                         /* this level hasn't been touched yet */
2967                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2968                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2969                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2970                                   path[i].p_hdr,
2971                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2972                 } else {
2973                         /* we were already here, see at next index */
2974                         path[i].p_idx--;
2975                 }
2976
2977                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2978                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2979                                 path[i].p_idx);
2980                 if (ext4_ext_more_to_rm(path + i)) {
2981                         struct buffer_head *bh;
2982                         /* go to the next level */
2983                         ext_debug("move to level %d (block %llu)\n",
2984                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2985                         memset(path + i + 1, 0, sizeof(*path));
2986                         bh = read_extent_tree_block(inode,
2987                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2988                                 EXT4_EX_NOCACHE);
2989                         if (IS_ERR(bh)) {
2990                                 /* should we reset i_size? */
2991                                 err = PTR_ERR(bh);
2992                                 break;
2993                         }
2994                         /* Yield here to deal with large extent trees.
2995                          * Should be a no-op if we did IO above. */
2996                         cond_resched();
2997                         if (WARN_ON(i + 1 > depth)) {
2998                                 err = -EFSCORRUPTED;
2999                                 break;
3000                         }
3001                         path[i + 1].p_bh = bh;
3002
3003                         /* save actual number of indexes since this
3004                          * number is changed at the next iteration */
3005                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3006                         i++;
3007                 } else {
3008                         /* we finished processing this index, go up */
3009                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3010                                 /* index is empty, remove it;
3011                                  * handle must be already prepared by the
3012                                  * truncatei_leaf() */
3013                                 err = ext4_ext_rm_idx(handle, inode, path, i);
3014                         }
3015                         /* root level has p_bh == NULL, brelse() eats this */
3016                         brelse(path[i].p_bh);
3017                         path[i].p_bh = NULL;
3018                         i--;
3019                         ext_debug("return to level %d\n", i);
3020                 }
3021         }
3022
3023         trace_ext4_ext_remove_space_done(inode, start, end, depth,
3024                         partial_cluster, path->p_hdr->eh_entries);
3025
3026         /*
3027          * If we still have something in the partial cluster and we have removed
3028          * even the first extent, then we should free the blocks in the partial
3029          * cluster as well.  (This code will only run when there are no leaves
3030          * to the immediate left of the truncated/punched region.)
3031          */
3032         if (partial_cluster > 0 && err == 0) {
3033                 /* don't zero partial_cluster since it's not used afterwards */
3034                 ext4_free_blocks(handle, inode, NULL,
3035                                  EXT4_C2B(sbi, partial_cluster),
3036                                  sbi->s_cluster_ratio,
3037                                  get_default_free_blocks_flags(inode));
3038         }
3039
3040         /* TODO: flexible tree reduction should be here */
3041         if (path->p_hdr->eh_entries == 0) {
3042                 /*
3043                  * truncate to zero freed all the tree,
3044                  * so we need to correct eh_depth
3045                  */
3046                 err = ext4_ext_get_access(handle, inode, path);
3047                 if (err == 0) {
3048                         ext_inode_hdr(inode)->eh_depth = 0;
3049                         ext_inode_hdr(inode)->eh_max =
3050                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3051                         err = ext4_ext_dirty(handle, inode, path);
3052                 }
3053         }
3054 out:
3055         ext4_ext_drop_refs(path);
3056         kfree(path);
3057         path = NULL;
3058         if (err == -EAGAIN)
3059                 goto again;
3060         ext4_journal_stop(handle);
3061
3062         return err;
3063 }
3064
3065 /*
3066  * called at mount time
3067  */
3068 void ext4_ext_init(struct super_block *sb)
3069 {
3070         /*
3071          * possible initialization would be here
3072          */
3073
3074         if (ext4_has_feature_extents(sb)) {
3075 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3076                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3077 #ifdef AGGRESSIVE_TEST
3078                        ", aggressive tests"
3079 #endif
3080 #ifdef CHECK_BINSEARCH
3081                        ", check binsearch"
3082 #endif
3083 #ifdef EXTENTS_STATS
3084                        ", stats"
3085 #endif
3086                        "\n");
3087 #endif
3088 #ifdef EXTENTS_STATS
3089                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3090                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3091                 EXT4_SB(sb)->s_ext_max = 0;
3092 #endif
3093         }
3094 }
3095
3096 /*
3097  * called at umount time
3098  */
3099 void ext4_ext_release(struct super_block *sb)
3100 {
3101         if (!ext4_has_feature_extents(sb))
3102                 return;
3103
3104 #ifdef EXTENTS_STATS
3105         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3106                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3107                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3108                         sbi->s_ext_blocks, sbi->s_ext_extents,
3109                         sbi->s_ext_blocks / sbi->s_ext_extents);
3110                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3111                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3112         }
3113 #endif
3114 }
3115
3116 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3117 {
3118         ext4_lblk_t  ee_block;
3119         ext4_fsblk_t ee_pblock;
3120         unsigned int ee_len;
3121
3122         ee_block  = le32_to_cpu(ex->ee_block);
3123         ee_len    = ext4_ext_get_actual_len(ex);
3124         ee_pblock = ext4_ext_pblock(ex);
3125
3126         if (ee_len == 0)
3127                 return 0;
3128
3129         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3130                                      EXTENT_STATUS_WRITTEN);
3131 }
3132
3133 /* FIXME!! we need to try to merge to left or right after zero-out  */
3134 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3135 {
3136         ext4_fsblk_t ee_pblock;
3137         unsigned int ee_len;
3138
3139         ee_len    = ext4_ext_get_actual_len(ex);
3140         ee_pblock = ext4_ext_pblock(ex);
3141         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3142                                   ee_len);
3143 }
3144
3145 /*
3146  * ext4_split_extent_at() splits an extent at given block.
3147  *
3148  * @handle: the journal handle
3149  * @inode: the file inode
3150  * @path: the path to the extent
3151  * @split: the logical block where the extent is splitted.
3152  * @split_flags: indicates if the extent could be zeroout if split fails, and
3153  *               the states(init or unwritten) of new extents.
3154  * @flags: flags used to insert new extent to extent tree.
3155  *
3156  *
3157  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3158  * of which are deterimined by split_flag.
3159  *
3160  * There are two cases:
3161  *  a> the extent are splitted into two extent.
3162  *  b> split is not needed, and just mark the extent.
3163  *
3164  * return 0 on success.
3165  */
3166 static int ext4_split_extent_at(handle_t *handle,
3167                              struct inode *inode,
3168                              struct ext4_ext_path **ppath,
3169                              ext4_lblk_t split,
3170                              int split_flag,
3171                              int flags)
3172 {
3173         struct ext4_ext_path *path = *ppath;
3174         ext4_fsblk_t newblock;
3175         ext4_lblk_t ee_block;
3176         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3177         struct ext4_extent *ex2 = NULL;
3178         unsigned int ee_len, depth;
3179         int err = 0;
3180
3181         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3182                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3183
3184         ext_debug("ext4_split_extents_at: inode %lu, logical"
3185                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3186
3187         ext4_ext_show_leaf(inode, path);
3188
3189         depth = ext_depth(inode);
3190         ex = path[depth].p_ext;
3191         ee_block = le32_to_cpu(ex->ee_block);
3192         ee_len = ext4_ext_get_actual_len(ex);
3193         newblock = split - ee_block + ext4_ext_pblock(ex);
3194
3195         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3196         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3197                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3198                              EXT4_EXT_MARK_UNWRIT1 |
3199                              EXT4_EXT_MARK_UNWRIT2));
3200
3201         err = ext4_ext_get_access(handle, inode, path + depth);
3202         if (err)
3203                 goto out;
3204
3205         if (split == ee_block) {
3206                 /*
3207                  * case b: block @split is the block that the extent begins with
3208                  * then we just change the state of the extent, and splitting
3209                  * is not needed.
3210                  */
3211                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3212                         ext4_ext_mark_unwritten(ex);
3213                 else
3214                         ext4_ext_mark_initialized(ex);
3215
3216                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3217                         ext4_ext_try_to_merge(handle, inode, path, ex);
3218
3219                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3220                 goto out;
3221         }
3222
3223         /* case a */
3224         memcpy(&orig_ex, ex, sizeof(orig_ex));
3225         ex->ee_len = cpu_to_le16(split - ee_block);
3226         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3227                 ext4_ext_mark_unwritten(ex);
3228
3229         /*
3230          * path may lead to new leaf, not to original leaf any more
3231          * after ext4_ext_insert_extent() returns,
3232          */
3233         err = ext4_ext_dirty(handle, inode, path + depth);
3234         if (err)
3235                 goto fix_extent_len;
3236
3237         ex2 = &newex;
3238         ex2->ee_block = cpu_to_le32(split);
3239         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3240         ext4_ext_store_pblock(ex2, newblock);
3241         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3242                 ext4_ext_mark_unwritten(ex2);
3243
3244         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3245         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3246                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3247                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3248                                 err = ext4_ext_zeroout(inode, ex2);
3249                                 zero_ex.ee_block = ex2->ee_block;
3250                                 zero_ex.ee_len = cpu_to_le16(
3251                                                 ext4_ext_get_actual_len(ex2));
3252                                 ext4_ext_store_pblock(&zero_ex,
3253                                                       ext4_ext_pblock(ex2));
3254                         } else {
3255                                 err = ext4_ext_zeroout(inode, ex);
3256                                 zero_ex.ee_block = ex->ee_block;
3257                                 zero_ex.ee_len = cpu_to_le16(
3258                                                 ext4_ext_get_actual_len(ex));
3259                                 ext4_ext_store_pblock(&zero_ex,
3260                                                       ext4_ext_pblock(ex));
3261                         }
3262                 } else {
3263                         err = ext4_ext_zeroout(inode, &orig_ex);
3264                         zero_ex.ee_block = orig_ex.ee_block;
3265                         zero_ex.ee_len = cpu_to_le16(
3266                                                 ext4_ext_get_actual_len(&orig_ex));
3267                         ext4_ext_store_pblock(&zero_ex,
3268                                               ext4_ext_pblock(&orig_ex));
3269                 }
3270
3271                 if (err)
3272                         goto fix_extent_len;
3273                 /* update the extent length and mark as initialized */
3274                 ex->ee_len = cpu_to_le16(ee_len);
3275                 ext4_ext_try_to_merge(handle, inode, path, ex);
3276                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3277                 if (err)
3278                         goto fix_extent_len;
3279
3280                 /* update extent status tree */
3281                 err = ext4_zeroout_es(inode, &zero_ex);
3282
3283                 goto out;
3284         } else if (err)
3285                 goto fix_extent_len;
3286
3287 out:
3288         ext4_ext_show_leaf(inode, path);
3289         return err;
3290
3291 fix_extent_len:
3292         ex->ee_len = orig_ex.ee_len;
3293         ext4_ext_dirty(handle, inode, path + path->p_depth);
3294         return err;
3295 }
3296
3297 /*
3298  * ext4_split_extents() splits an extent and mark extent which is covered
3299  * by @map as split_flags indicates
3300  *
3301  * It may result in splitting the extent into multiple extents (up to three)
3302  * There are three possibilities:
3303  *   a> There is no split required
3304  *   b> Splits in two extents: Split is happening at either end of the extent
3305  *   c> Splits in three extents: Somone is splitting in middle of the extent
3306  *
3307  */
3308 static int ext4_split_extent(handle_t *handle,
3309                               struct inode *inode,
3310                               struct ext4_ext_path **ppath,
3311                               struct ext4_map_blocks *map,
3312                               int split_flag,
3313                               int flags)
3314 {
3315         struct ext4_ext_path *path = *ppath;
3316         ext4_lblk_t ee_block;
3317         struct ext4_extent *ex;
3318         unsigned int ee_len, depth;
3319         int err = 0;
3320         int unwritten;
3321         int split_flag1, flags1;
3322         int allocated = map->m_len;
3323
3324         depth = ext_depth(inode);
3325         ex = path[depth].p_ext;
3326         ee_block = le32_to_cpu(ex->ee_block);
3327         ee_len = ext4_ext_get_actual_len(ex);
3328         unwritten = ext4_ext_is_unwritten(ex);
3329
3330         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3331                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3332                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3333                 if (unwritten)
3334                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3335                                        EXT4_EXT_MARK_UNWRIT2;
3336                 if (split_flag & EXT4_EXT_DATA_VALID2)
3337                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3338                 err = ext4_split_extent_at(handle, inode, ppath,
3339                                 map->m_lblk + map->m_len, split_flag1, flags1);
3340                 if (err)
3341                         goto out;
3342         } else {
3343                 allocated = ee_len - (map->m_lblk - ee_block);
3344         }
3345         /*
3346          * Update path is required because previous ext4_split_extent_at() may
3347          * result in split of original leaf or extent zeroout.
3348          */
3349         path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3350         if (IS_ERR(path))
3351                 return PTR_ERR(path);
3352         depth = ext_depth(inode);
3353         ex = path[depth].p_ext;
3354         if (!ex) {
3355                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3356                                  (unsigned long) map->m_lblk);
3357                 return -EFSCORRUPTED;
3358         }
3359         unwritten = ext4_ext_is_unwritten(ex);
3360         split_flag1 = 0;
3361
3362         if (map->m_lblk >= ee_block) {
3363                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3364                 if (unwritten) {
3365                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3366                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3367                                                      EXT4_EXT_MARK_UNWRIT2);
3368                 }
3369                 err = ext4_split_extent_at(handle, inode, ppath,
3370                                 map->m_lblk, split_flag1, flags);
3371                 if (err)
3372                         goto out;
3373         }
3374
3375         ext4_ext_show_leaf(inode, path);
3376 out:
3377         return err ? err : allocated;
3378 }
3379
3380 /*
3381  * This function is called by ext4_ext_map_blocks() if someone tries to write
3382  * to an unwritten extent. It may result in splitting the unwritten
3383  * extent into multiple extents (up to three - one initialized and two
3384  * unwritten).
3385  * There are three possibilities:
3386  *   a> There is no split required: Entire extent should be initialized
3387  *   b> Splits in two extents: Write is happening at either end of the extent
3388  *   c> Splits in three extents: Somone is writing in middle of the extent
3389  *
3390  * Pre-conditions:
3391  *  - The extent pointed to by 'path' is unwritten.
3392  *  - The extent pointed to by 'path' contains a superset
3393  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3394  *
3395  * Post-conditions on success:
3396  *  - the returned value is the number of blocks beyond map->l_lblk
3397  *    that are allocated and initialized.
3398  *    It is guaranteed to be >= map->m_len.
3399  */
3400 static int ext4_ext_convert_to_initialized(handle_t *handle,
3401                                            struct inode *inode,
3402                                            struct ext4_map_blocks *map,
3403                                            struct ext4_ext_path **ppath,
3404                                            int flags)
3405 {
3406         struct ext4_ext_path *path = *ppath;
3407         struct ext4_sb_info *sbi;
3408         struct ext4_extent_header *eh;
3409         struct ext4_map_blocks split_map;
3410         struct ext4_extent zero_ex;
3411         struct ext4_extent *ex, *abut_ex;
3412         ext4_lblk_t ee_block, eof_block;
3413         unsigned int ee_len, depth, map_len = map->m_len;
3414         int allocated = 0, max_zeroout = 0;
3415         int err = 0;
3416         int split_flag = 0;
3417
3418         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3419                 "block %llu, max_blocks %u\n", inode->i_ino,
3420                 (unsigned long long)map->m_lblk, map_len);
3421
3422         sbi = EXT4_SB(inode->i_sb);
3423         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3424                 inode->i_sb->s_blocksize_bits;
3425         if (eof_block < map->m_lblk + map_len)
3426                 eof_block = map->m_lblk + map_len;
3427
3428         depth = ext_depth(inode);
3429         eh = path[depth].p_hdr;
3430         ex = path[depth].p_ext;
3431         ee_block = le32_to_cpu(ex->ee_block);
3432         ee_len = ext4_ext_get_actual_len(ex);
3433         zero_ex.ee_len = 0;
3434
3435         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3436
3437         /* Pre-conditions */
3438         BUG_ON(!ext4_ext_is_unwritten(ex));
3439         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3440
3441         /*
3442          * Attempt to transfer newly initialized blocks from the currently
3443          * unwritten extent to its neighbor. This is much cheaper
3444          * than an insertion followed by a merge as those involve costly
3445          * memmove() calls. Transferring to the left is the common case in
3446          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3447          * followed by append writes.
3448          *
3449          * Limitations of the current logic:
3450          *  - L1: we do not deal with writes covering the whole extent.
3451          *    This would require removing the extent if the transfer
3452          *    is possible.
3453          *  - L2: we only attempt to merge with an extent stored in the
3454          *    same extent tree node.
3455          */
3456         if ((map->m_lblk == ee_block) &&
3457                 /* See if we can merge left */
3458                 (map_len < ee_len) &&           /*L1*/
3459                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3460                 ext4_lblk_t prev_lblk;
3461                 ext4_fsblk_t prev_pblk, ee_pblk;
3462                 unsigned int prev_len;
3463
3464                 abut_ex = ex - 1;
3465                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3466                 prev_len = ext4_ext_get_actual_len(abut_ex);
3467                 prev_pblk = ext4_ext_pblock(abut_ex);
3468                 ee_pblk = ext4_ext_pblock(ex);
3469
3470                 /*
3471                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3472                  * upon those conditions:
3473                  * - C1: abut_ex is initialized,
3474                  * - C2: abut_ex is logically abutting ex,
3475                  * - C3: abut_ex is physically abutting ex,
3476                  * - C4: abut_ex can receive the additional blocks without
3477                  *   overflowing the (initialized) length limit.
3478                  */
3479                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3480                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3481                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3482                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3483                         err = ext4_ext_get_access(handle, inode, path + depth);
3484                         if (err)
3485                                 goto out;
3486
3487                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3488                                 map, ex, abut_ex);
3489
3490                         /* Shift the start of ex by 'map_len' blocks */
3491                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3492                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3493                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3494                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3495
3496                         /* Extend abut_ex by 'map_len' blocks */
3497                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3498
3499                         /* Result: number of initialized blocks past m_lblk */
3500                         allocated = map_len;
3501                 }
3502         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3503                    (map_len < ee_len) &&        /*L1*/
3504                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3505                 /* See if we can merge right */
3506                 ext4_lblk_t next_lblk;
3507                 ext4_fsblk_t next_pblk, ee_pblk;
3508                 unsigned int next_len;
3509
3510                 abut_ex = ex + 1;
3511                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3512                 next_len = ext4_ext_get_actual_len(abut_ex);
3513                 next_pblk = ext4_ext_pblock(abut_ex);
3514                 ee_pblk = ext4_ext_pblock(ex);
3515
3516                 /*
3517                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3518                  * upon those conditions:
3519                  * - C1: abut_ex is initialized,
3520                  * - C2: abut_ex is logically abutting ex,
3521                  * - C3: abut_ex is physically abutting ex,
3522                  * - C4: abut_ex can receive the additional blocks without
3523                  *   overflowing the (initialized) length limit.
3524                  */
3525                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3526                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3527                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3528                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3529                         err = ext4_ext_get_access(handle, inode, path + depth);
3530                         if (err)
3531                                 goto out;
3532
3533                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3534                                 map, ex, abut_ex);
3535
3536                         /* Shift the start of abut_ex by 'map_len' blocks */
3537                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3538                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3539                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3540                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3541
3542                         /* Extend abut_ex by 'map_len' blocks */
3543                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3544
3545                         /* Result: number of initialized blocks past m_lblk */
3546                         allocated = map_len;
3547                 }
3548         }
3549         if (allocated) {
3550                 /* Mark the block containing both extents as dirty */
3551                 ext4_ext_dirty(handle, inode, path + depth);
3552
3553                 /* Update path to point to the right extent */
3554                 path[depth].p_ext = abut_ex;
3555                 goto out;
3556         } else
3557                 allocated = ee_len - (map->m_lblk - ee_block);
3558
3559         WARN_ON(map->m_lblk < ee_block);
3560         /*
3561          * It is safe to convert extent to initialized via explicit
3562          * zeroout only if extent is fully inside i_size or new_size.
3563          */
3564         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3565
3566         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3567                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3568                         (inode->i_sb->s_blocksize_bits - 10);
3569
3570         if (ext4_encrypted_inode(inode))
3571                 max_zeroout = 0;
3572
3573         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3574         if (max_zeroout && (ee_len <= max_zeroout)) {
3575                 err = ext4_ext_zeroout(inode, ex);
3576                 if (err)
3577                         goto out;
3578                 zero_ex.ee_block = ex->ee_block;
3579                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3580                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3581
3582                 err = ext4_ext_get_access(handle, inode, path + depth);
3583                 if (err)
3584                         goto out;
3585                 ext4_ext_mark_initialized(ex);
3586                 ext4_ext_try_to_merge(handle, inode, path, ex);
3587                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3588                 goto out;
3589         }
3590
3591         /*
3592          * four cases:
3593          * 1. split the extent into three extents.
3594          * 2. split the extent into two extents, zeroout the first half.
3595          * 3. split the extent into two extents, zeroout the second half.
3596          * 4. split the extent into two extents with out zeroout.
3597          */
3598         split_map.m_lblk = map->m_lblk;
3599         split_map.m_len = map->m_len;
3600
3601         if (max_zeroout && (allocated > map->m_len)) {
3602                 if (allocated <= max_zeroout) {
3603                         /* case 3 */
3604                         zero_ex.ee_block =
3605                                          cpu_to_le32(map->m_lblk);
3606                         zero_ex.ee_len = cpu_to_le16(allocated);
3607                         ext4_ext_store_pblock(&zero_ex,
3608                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3609                         err = ext4_ext_zeroout(inode, &zero_ex);
3610                         if (err)
3611                                 goto out;
3612                         split_map.m_lblk = map->m_lblk;
3613                         split_map.m_len = allocated;
3614                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3615                         /* case 2 */
3616                         if (map->m_lblk != ee_block) {
3617                                 zero_ex.ee_block = ex->ee_block;
3618                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3619                                                         ee_block);
3620                                 ext4_ext_store_pblock(&zero_ex,
3621                                                       ext4_ext_pblock(ex));
3622                                 err = ext4_ext_zeroout(inode, &zero_ex);
3623                                 if (err)
3624                                         goto out;
3625                         }
3626
3627                         split_map.m_lblk = ee_block;
3628                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3629                         allocated = map->m_len;
3630                 }
3631         }
3632
3633         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3634                                 flags);
3635         if (err > 0)
3636                 err = 0;
3637 out:
3638         /* If we have gotten a failure, don't zero out status tree */
3639         if (!err)
3640                 err = ext4_zeroout_es(inode, &zero_ex);
3641         return err ? err : allocated;
3642 }
3643
3644 /*
3645  * This function is called by ext4_ext_map_blocks() from
3646  * ext4_get_blocks_dio_write() when DIO to write
3647  * to an unwritten extent.
3648  *
3649  * Writing to an unwritten extent may result in splitting the unwritten
3650  * extent into multiple initialized/unwritten extents (up to three)
3651  * There are three possibilities:
3652  *   a> There is no split required: Entire extent should be unwritten
3653  *   b> Splits in two extents: Write is happening at either end of the extent
3654  *   c> Splits in three extents: Somone is writing in middle of the extent
3655  *
3656  * This works the same way in the case of initialized -> unwritten conversion.
3657  *
3658  * One of more index blocks maybe needed if the extent tree grow after
3659  * the unwritten extent split. To prevent ENOSPC occur at the IO
3660  * complete, we need to split the unwritten extent before DIO submit
3661  * the IO. The unwritten extent called at this time will be split
3662  * into three unwritten extent(at most). After IO complete, the part
3663  * being filled will be convert to initialized by the end_io callback function
3664  * via ext4_convert_unwritten_extents().
3665  *
3666  * Returns the size of unwritten extent to be written on success.
3667  */
3668 static int ext4_split_convert_extents(handle_t *handle,
3669                                         struct inode *inode,
3670                                         struct ext4_map_blocks *map,
3671                                         struct ext4_ext_path **ppath,
3672                                         int flags)
3673 {
3674         struct ext4_ext_path *path = *ppath;
3675         ext4_lblk_t eof_block;
3676         ext4_lblk_t ee_block;
3677         struct ext4_extent *ex;
3678         unsigned int ee_len;
3679         int split_flag = 0, depth;
3680
3681         ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3682                   __func__, inode->i_ino,
3683                   (unsigned long long)map->m_lblk, map->m_len);
3684
3685         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3686                 inode->i_sb->s_blocksize_bits;
3687         if (eof_block < map->m_lblk + map->m_len)
3688                 eof_block = map->m_lblk + map->m_len;
3689         /*
3690          * It is safe to convert extent to initialized via explicit
3691          * zeroout only if extent is fully insde i_size or new_size.
3692          */
3693         depth = ext_depth(inode);
3694         ex = path[depth].p_ext;
3695         ee_block = le32_to_cpu(ex->ee_block);
3696         ee_len = ext4_ext_get_actual_len(ex);
3697
3698         /* Convert to unwritten */
3699         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3700                 split_flag |= EXT4_EXT_DATA_VALID1;
3701         /* Convert to initialized */
3702         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3703                 split_flag |= ee_block + ee_len <= eof_block ?
3704                               EXT4_EXT_MAY_ZEROOUT : 0;
3705                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3706         }
3707         flags |= EXT4_GET_BLOCKS_PRE_IO;
3708         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3709 }
3710
3711 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3712                                                 struct inode *inode,
3713                                                 struct ext4_map_blocks *map,
3714                                                 struct ext4_ext_path **ppath)
3715 {
3716         struct ext4_ext_path *path = *ppath;
3717         struct ext4_extent *ex;
3718         ext4_lblk_t ee_block;
3719         unsigned int ee_len;
3720         int depth;
3721         int err = 0;
3722
3723         depth = ext_depth(inode);
3724         ex = path[depth].p_ext;
3725         ee_block = le32_to_cpu(ex->ee_block);
3726         ee_len = ext4_ext_get_actual_len(ex);
3727
3728         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3729                 "block %llu, max_blocks %u\n", inode->i_ino,
3730                   (unsigned long long)ee_block, ee_len);
3731
3732         /* If extent is larger than requested it is a clear sign that we still
3733          * have some extent state machine issues left. So extent_split is still
3734          * required.
3735          * TODO: Once all related issues will be fixed this situation should be
3736          * illegal.
3737          */
3738         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3739 #ifdef EXT4_DEBUG
3740                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3741                              " len %u; IO logical block %llu, len %u\n",
3742                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3743                              (unsigned long long)map->m_lblk, map->m_len);
3744 #endif
3745                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3746                                                  EXT4_GET_BLOCKS_CONVERT);
3747                 if (err < 0)
3748                         return err;
3749                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3750                 if (IS_ERR(path))
3751                         return PTR_ERR(path);
3752                 depth = ext_depth(inode);
3753                 ex = path[depth].p_ext;
3754         }
3755
3756         err = ext4_ext_get_access(handle, inode, path + depth);
3757         if (err)
3758                 goto out;
3759         /* first mark the extent as initialized */
3760         ext4_ext_mark_initialized(ex);
3761
3762         /* note: ext4_ext_correct_indexes() isn't needed here because
3763          * borders are not changed
3764          */
3765         ext4_ext_try_to_merge(handle, inode, path, ex);
3766
3767         /* Mark modified extent as dirty */
3768         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3769 out:
3770         ext4_ext_show_leaf(inode, path);
3771         return err;
3772 }
3773
3774 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3775                         sector_t block, int count)
3776 {
3777         int i;
3778         for (i = 0; i < count; i++)
3779                 unmap_underlying_metadata(bdev, block + i);
3780 }
3781
3782 /*
3783  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3784  */
3785 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3786                               ext4_lblk_t lblk,
3787                               struct ext4_ext_path *path,
3788                               unsigned int len)
3789 {
3790         int i, depth;
3791         struct ext4_extent_header *eh;
3792         struct ext4_extent *last_ex;
3793
3794         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3795                 return 0;
3796
3797         depth = ext_depth(inode);
3798         eh = path[depth].p_hdr;
3799
3800         /*
3801          * We're going to remove EOFBLOCKS_FL entirely in future so we
3802          * do not care for this case anymore. Simply remove the flag
3803          * if there are no extents.
3804          */
3805         if (unlikely(!eh->eh_entries))
3806                 goto out;
3807         last_ex = EXT_LAST_EXTENT(eh);
3808         /*
3809          * We should clear the EOFBLOCKS_FL flag if we are writing the
3810          * last block in the last extent in the file.  We test this by
3811          * first checking to see if the caller to
3812          * ext4_ext_get_blocks() was interested in the last block (or
3813          * a block beyond the last block) in the current extent.  If
3814          * this turns out to be false, we can bail out from this
3815          * function immediately.
3816          */
3817         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3818             ext4_ext_get_actual_len(last_ex))
3819                 return 0;
3820         /*
3821          * If the caller does appear to be planning to write at or
3822          * beyond the end of the current extent, we then test to see
3823          * if the current extent is the last extent in the file, by
3824          * checking to make sure it was reached via the rightmost node
3825          * at each level of the tree.
3826          */
3827         for (i = depth-1; i >= 0; i--)
3828                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3829                         return 0;
3830 out:
3831         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3832         return ext4_mark_inode_dirty(handle, inode);
3833 }
3834
3835 /**
3836  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3837  *
3838  * Return 1 if there is a delalloc block in the range, otherwise 0.
3839  */
3840 int ext4_find_delalloc_range(struct inode *inode,
3841                              ext4_lblk_t lblk_start,
3842                              ext4_lblk_t lblk_end)
3843 {
3844         struct extent_status es;
3845
3846         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3847         if (es.es_len == 0)
3848                 return 0; /* there is no delay extent in this tree */
3849         else if (es.es_lblk <= lblk_start &&
3850                  lblk_start < es.es_lblk + es.es_len)
3851                 return 1;
3852         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3853                 return 1;
3854         else
3855                 return 0;
3856 }
3857
3858 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3859 {
3860         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3861         ext4_lblk_t lblk_start, lblk_end;
3862         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3863         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3864
3865         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3866 }
3867
3868 /**
3869  * Determines how many complete clusters (out of those specified by the 'map')
3870  * are under delalloc and were reserved quota for.
3871  * This function is called when we are writing out the blocks that were
3872  * originally written with their allocation delayed, but then the space was
3873  * allocated using fallocate() before the delayed allocation could be resolved.
3874  * The cases to look for are:
3875  * ('=' indicated delayed allocated blocks
3876  *  '-' indicates non-delayed allocated blocks)
3877  * (a) partial clusters towards beginning and/or end outside of allocated range
3878  *     are not delalloc'ed.
3879  *      Ex:
3880  *      |----c---=|====c====|====c====|===-c----|
3881  *               |++++++ allocated ++++++|
3882  *      ==> 4 complete clusters in above example
3883  *
3884  * (b) partial cluster (outside of allocated range) towards either end is
3885  *     marked for delayed allocation. In this case, we will exclude that
3886  *     cluster.
3887  *      Ex:
3888  *      |----====c========|========c========|
3889  *           |++++++ allocated ++++++|
3890  *      ==> 1 complete clusters in above example
3891  *
3892  *      Ex:
3893  *      |================c================|
3894  *            |++++++ allocated ++++++|
3895  *      ==> 0 complete clusters in above example
3896  *
3897  * The ext4_da_update_reserve_space will be called only if we
3898  * determine here that there were some "entire" clusters that span
3899  * this 'allocated' range.
3900  * In the non-bigalloc case, this function will just end up returning num_blks
3901  * without ever calling ext4_find_delalloc_range.
3902  */
3903 static unsigned int
3904 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3905                            unsigned int num_blks)
3906 {
3907         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3908         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3909         ext4_lblk_t lblk_from, lblk_to, c_offset;
3910         unsigned int allocated_clusters = 0;
3911
3912         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3913         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3914
3915         /* max possible clusters for this allocation */
3916         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3917
3918         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3919
3920         /* Check towards left side */
3921         c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3922         if (c_offset) {
3923                 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3924                 lblk_to = lblk_from + c_offset - 1;
3925
3926                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3927                         allocated_clusters--;
3928         }
3929
3930         /* Now check towards right. */
3931         c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3932         if (allocated_clusters && c_offset) {
3933                 lblk_from = lblk_start + num_blks;
3934                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3935
3936                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3937                         allocated_clusters--;
3938         }
3939
3940         return allocated_clusters;
3941 }
3942
3943 static int
3944 convert_initialized_extent(handle_t *handle, struct inode *inode,
3945                            struct ext4_map_blocks *map,
3946                            struct ext4_ext_path **ppath,
3947                            unsigned int allocated)
3948 {
3949         struct ext4_ext_path *path = *ppath;
3950         struct ext4_extent *ex;
3951         ext4_lblk_t ee_block;
3952         unsigned int ee_len;
3953         int depth;
3954         int err = 0;
3955
3956         /*
3957          * Make sure that the extent is no bigger than we support with
3958          * unwritten extent
3959          */
3960         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3961                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3962
3963         depth = ext_depth(inode);
3964         ex = path[depth].p_ext;
3965         ee_block = le32_to_cpu(ex->ee_block);
3966         ee_len = ext4_ext_get_actual_len(ex);
3967
3968         ext_debug("%s: inode %lu, logical"
3969                 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3970                   (unsigned long long)ee_block, ee_len);
3971
3972         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3973                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3974                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3975                 if (err < 0)
3976                         return err;
3977                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3978                 if (IS_ERR(path))
3979                         return PTR_ERR(path);
3980                 depth = ext_depth(inode);
3981                 ex = path[depth].p_ext;
3982                 if (!ex) {
3983                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3984                                          (unsigned long) map->m_lblk);
3985                         return -EFSCORRUPTED;
3986                 }
3987         }
3988
3989         err = ext4_ext_get_access(handle, inode, path + depth);
3990         if (err)
3991                 return err;
3992         /* first mark the extent as unwritten */
3993         ext4_ext_mark_unwritten(ex);
3994
3995         /* note: ext4_ext_correct_indexes() isn't needed here because
3996          * borders are not changed
3997          */
3998         ext4_ext_try_to_merge(handle, inode, path, ex);
3999
4000         /* Mark modified extent as dirty */
4001         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
4002         if (err)
4003                 return err;
4004         ext4_ext_show_leaf(inode, path);
4005
4006         ext4_update_inode_fsync_trans(handle, inode, 1);
4007         err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
4008         if (err)
4009                 return err;
4010         map->m_flags |= EXT4_MAP_UNWRITTEN;
4011         if (allocated > map->m_len)
4012                 allocated = map->m_len;
4013         map->m_len = allocated;
4014         return allocated;
4015 }
4016
4017 static int
4018 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4019                         struct ext4_map_blocks *map,
4020                         struct ext4_ext_path **ppath, int flags,
4021                         unsigned int allocated, ext4_fsblk_t newblock)
4022 {
4023         struct ext4_ext_path *path = *ppath;
4024         int ret = 0;
4025         int err = 0;
4026
4027         ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4028                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
4029                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4030                   flags, allocated);
4031         ext4_ext_show_leaf(inode, path);
4032
4033         /*
4034          * When writing into unwritten space, we should not fail to
4035          * allocate metadata blocks for the new extent block if needed.
4036          */
4037         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4038
4039         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4040                                                     allocated, newblock);
4041
4042         /* get_block() before submit the IO, split the extent */
4043         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4044                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4045                                          flags | EXT4_GET_BLOCKS_CONVERT);
4046                 if (ret <= 0)
4047                         goto out;
4048                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4049                 goto out;
4050         }
4051         /* IO end_io complete, convert the filled extent to written */
4052         if (flags & EXT4_GET_BLOCKS_CONVERT) {
4053                 if (flags & EXT4_GET_BLOCKS_ZERO) {
4054                         if (allocated > map->m_len)
4055                                 allocated = map->m_len;
4056                         err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4057                                                  allocated);
4058                         if (err < 0)
4059                                 goto out2;
4060                 }
4061                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4062                                                            ppath);
4063                 if (ret >= 0) {
4064                         ext4_update_inode_fsync_trans(handle, inode, 1);
4065                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
4066                                                  path, map->m_len);
4067                 } else
4068                         err = ret;
4069                 map->m_flags |= EXT4_MAP_MAPPED;
4070                 map->m_pblk = newblock;
4071                 if (allocated > map->m_len)
4072                         allocated = map->m_len;
4073                 map->m_len = allocated;
4074                 goto out2;
4075         }
4076         /* buffered IO case */
4077         /*
4078          * repeat fallocate creation request
4079          * we already have an unwritten extent
4080          */
4081         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4082                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4083                 goto map_out;
4084         }
4085
4086         /* buffered READ or buffered write_begin() lookup */
4087         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4088                 /*
4089                  * We have blocks reserved already.  We
4090                  * return allocated blocks so that delalloc
4091                  * won't do block reservation for us.  But
4092                  * the buffer head will be unmapped so that
4093                  * a read from the block returns 0s.
4094                  */
4095                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4096                 goto out1;
4097         }
4098
4099         /* buffered write, writepage time, convert*/
4100         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4101         if (ret >= 0)
4102                 ext4_update_inode_fsync_trans(handle, inode, 1);
4103 out:
4104         if (ret <= 0) {
4105                 err = ret;
4106                 goto out2;
4107         } else
4108                 allocated = ret;
4109         map->m_flags |= EXT4_MAP_NEW;
4110         /*
4111          * if we allocated more blocks than requested
4112          * we need to make sure we unmap the extra block
4113          * allocated. The actual needed block will get
4114          * unmapped later when we find the buffer_head marked
4115          * new.
4116          */
4117         if (allocated > map->m_len) {
4118                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4119                                         newblock + map->m_len,
4120                                         allocated - map->m_len);
4121                 allocated = map->m_len;
4122         }
4123         map->m_len = allocated;
4124
4125         /*
4126          * If we have done fallocate with the offset that is already
4127          * delayed allocated, we would have block reservation
4128          * and quota reservation done in the delayed write path.
4129          * But fallocate would have already updated quota and block
4130          * count for this offset. So cancel these reservation
4131          */
4132         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4133                 unsigned int reserved_clusters;
4134                 reserved_clusters = get_reserved_cluster_alloc(inode,
4135                                 map->m_lblk, map->m_len);
4136                 if (reserved_clusters)
4137                         ext4_da_update_reserve_space(inode,
4138                                                      reserved_clusters,
4139                                                      0);
4140         }
4141
4142 map_out:
4143         map->m_flags |= EXT4_MAP_MAPPED;
4144         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4145                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4146                                          map->m_len);
4147                 if (err < 0)
4148                         goto out2;
4149         }
4150 out1:
4151         if (allocated > map->m_len)
4152                 allocated = map->m_len;
4153         ext4_ext_show_leaf(inode, path);
4154         map->m_pblk = newblock;
4155         map->m_len = allocated;
4156 out2:
4157         return err ? err : allocated;
4158 }
4159
4160 /*
4161  * get_implied_cluster_alloc - check to see if the requested
4162  * allocation (in the map structure) overlaps with a cluster already
4163  * allocated in an extent.
4164  *      @sb     The filesystem superblock structure
4165  *      @map    The requested lblk->pblk mapping
4166  *      @ex     The extent structure which might contain an implied
4167  *                      cluster allocation
4168  *
4169  * This function is called by ext4_ext_map_blocks() after we failed to
4170  * find blocks that were already in the inode's extent tree.  Hence,
4171  * we know that the beginning of the requested region cannot overlap
4172  * the extent from the inode's extent tree.  There are three cases we
4173  * want to catch.  The first is this case:
4174  *
4175  *               |--- cluster # N--|
4176  *    |--- extent ---|  |---- requested region ---|
4177  *                      |==========|
4178  *
4179  * The second case that we need to test for is this one:
4180  *
4181  *   |--------- cluster # N ----------------|
4182  *         |--- requested region --|   |------- extent ----|
4183  *         |=======================|
4184  *
4185  * The third case is when the requested region lies between two extents
4186  * within the same cluster:
4187  *          |------------- cluster # N-------------|
4188  * |----- ex -----|                  |---- ex_right ----|
4189  *                  |------ requested region ------|
4190  *                  |================|
4191  *
4192  * In each of the above cases, we need to set the map->m_pblk and
4193  * map->m_len so it corresponds to the return the extent labelled as
4194  * "|====|" from cluster #N, since it is already in use for data in
4195  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4196  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4197  * as a new "allocated" block region.  Otherwise, we will return 0 and
4198  * ext4_ext_map_blocks() will then allocate one or more new clusters
4199  * by calling ext4_mb_new_blocks().
4200  */
4201 static int get_implied_cluster_alloc(struct super_block *sb,
4202                                      struct ext4_map_blocks *map,
4203                                      struct ext4_extent *ex,
4204                                      struct ext4_ext_path *path)
4205 {
4206         struct ext4_sb_info *sbi = EXT4_SB(sb);
4207         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4208         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4209         ext4_lblk_t rr_cluster_start;
4210         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4211         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4212         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4213
4214         /* The extent passed in that we are trying to match */
4215         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4216         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4217
4218         /* The requested region passed into ext4_map_blocks() */
4219         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4220
4221         if ((rr_cluster_start == ex_cluster_end) ||
4222             (rr_cluster_start == ex_cluster_start)) {
4223                 if (rr_cluster_start == ex_cluster_end)
4224                         ee_start += ee_len - 1;
4225                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4226                 map->m_len = min(map->m_len,
4227                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4228                 /*
4229                  * Check for and handle this case:
4230                  *
4231                  *   |--------- cluster # N-------------|
4232                  *                     |------- extent ----|
4233                  *         |--- requested region ---|
4234                  *         |===========|
4235                  */
4236
4237                 if (map->m_lblk < ee_block)
4238                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4239
4240                 /*
4241                  * Check for the case where there is already another allocated
4242                  * block to the right of 'ex' but before the end of the cluster.
4243                  *
4244                  *          |------------- cluster # N-------------|
4245                  * |----- ex -----|                  |---- ex_right ----|
4246                  *                  |------ requested region ------|
4247                  *                  |================|
4248                  */
4249                 if (map->m_lblk > ee_block) {
4250                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4251                         map->m_len = min(map->m_len, next - map->m_lblk);
4252                 }
4253
4254                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4255                 return 1;
4256         }
4257
4258         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4259         return 0;
4260 }
4261
4262
4263 /*
4264  * Block allocation/map/preallocation routine for extents based files
4265  *
4266  *
4267  * Need to be called with
4268  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4269  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4270  *
4271  * return > 0, number of of blocks already mapped/allocated
4272  *          if create == 0 and these are pre-allocated blocks
4273  *              buffer head is unmapped
4274  *          otherwise blocks are mapped
4275  *
4276  * return = 0, if plain look up failed (blocks have not been allocated)
4277  *          buffer head is unmapped
4278  *
4279  * return < 0, error case.
4280  */
4281 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4282                         struct ext4_map_blocks *map, int flags)
4283 {
4284         struct ext4_ext_path *path = NULL;
4285         struct ext4_extent newex, *ex, *ex2;
4286         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4287         ext4_fsblk_t newblock = 0;
4288         int free_on_err = 0, err = 0, depth, ret;
4289         unsigned int allocated = 0, offset = 0;
4290         unsigned int allocated_clusters = 0;
4291         struct ext4_allocation_request ar;
4292         ext4_lblk_t cluster_offset;
4293         bool map_from_cluster = false;
4294
4295         ext_debug("blocks %u/%u requested for inode %lu\n",
4296                   map->m_lblk, map->m_len, inode->i_ino);
4297         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4298
4299         /* find extent for this block */
4300         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4301         if (IS_ERR(path)) {
4302                 err = PTR_ERR(path);
4303                 path = NULL;
4304                 goto out2;
4305         }
4306
4307         depth = ext_depth(inode);
4308
4309         /*
4310          * consistent leaf must not be empty;
4311          * this situation is possible, though, _during_ tree modification;
4312          * this is why assert can't be put in ext4_find_extent()
4313          */
4314         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4315                 EXT4_ERROR_INODE(inode, "bad extent address "
4316                                  "lblock: %lu, depth: %d pblock %lld",
4317                                  (unsigned long) map->m_lblk, depth,
4318                                  path[depth].p_block);
4319                 err = -EFSCORRUPTED;
4320                 goto out2;
4321         }
4322
4323         ex = path[depth].p_ext;
4324         if (ex) {
4325                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4326                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4327                 unsigned short ee_len;
4328
4329
4330                 /*
4331                  * unwritten extents are treated as holes, except that
4332                  * we split out initialized portions during a write.
4333                  */
4334                 ee_len = ext4_ext_get_actual_len(ex);
4335
4336                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4337
4338                 /* if found extent covers block, simply return it */
4339                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4340                         newblock = map->m_lblk - ee_block + ee_start;
4341                         /* number of remaining blocks in the extent */
4342                         allocated = ee_len - (map->m_lblk - ee_block);
4343                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4344                                   ee_block, ee_len, newblock);
4345
4346                         /*
4347                          * If the extent is initialized check whether the
4348                          * caller wants to convert it to unwritten.
4349                          */
4350                         if ((!ext4_ext_is_unwritten(ex)) &&
4351                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4352                                 allocated = convert_initialized_extent(
4353                                                 handle, inode, map, &path,
4354                                                 allocated);
4355                                 goto out2;
4356                         } else if (!ext4_ext_is_unwritten(ex))
4357                                 goto out;
4358
4359                         ret = ext4_ext_handle_unwritten_extents(
4360                                 handle, inode, map, &path, flags,
4361                                 allocated, newblock);
4362                         if (ret < 0)
4363                                 err = ret;
4364                         else
4365                                 allocated = ret;
4366                         goto out2;
4367                 }
4368         }
4369
4370         /*
4371          * requested block isn't allocated yet;
4372          * we couldn't try to create block if create flag is zero
4373          */
4374         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4375                 ext4_lblk_t hole_start, hole_len;
4376
4377                 hole_start = map->m_lblk;
4378                 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4379                 /*
4380                  * put just found gap into cache to speed up
4381                  * subsequent requests
4382                  */
4383                 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4384
4385                 /* Update hole_len to reflect hole size after map->m_lblk */
4386                 if (hole_start != map->m_lblk)
4387                         hole_len -= map->m_lblk - hole_start;
4388                 map->m_pblk = 0;
4389                 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4390
4391                 goto out2;
4392         }
4393
4394         /*
4395          * Okay, we need to do block allocation.
4396          */
4397         newex.ee_block = cpu_to_le32(map->m_lblk);
4398         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4399
4400         /*
4401          * If we are doing bigalloc, check to see if the extent returned
4402          * by ext4_find_extent() implies a cluster we can use.
4403          */
4404         if (cluster_offset && ex &&
4405             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4406                 ar.len = allocated = map->m_len;
4407                 newblock = map->m_pblk;
4408                 map_from_cluster = true;
4409                 goto got_allocated_blocks;
4410         }
4411
4412         /* find neighbour allocated blocks */
4413         ar.lleft = map->m_lblk;
4414         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4415         if (err)
4416                 goto out2;
4417         ar.lright = map->m_lblk;
4418         ex2 = NULL;
4419         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4420         if (err)
4421                 goto out2;
4422
4423         /* Check if the extent after searching to the right implies a
4424          * cluster we can use. */
4425         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4426             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4427                 ar.len = allocated = map->m_len;
4428                 newblock = map->m_pblk;
4429                 map_from_cluster = true;
4430                 goto got_allocated_blocks;
4431         }
4432
4433         /*
4434          * See if request is beyond maximum number of blocks we can have in
4435          * a single extent. For an initialized extent this limit is
4436          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4437          * EXT_UNWRITTEN_MAX_LEN.
4438          */
4439         if (map->m_len > EXT_INIT_MAX_LEN &&
4440             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4441                 map->m_len = EXT_INIT_MAX_LEN;
4442         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4443                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4444                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4445
4446         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4447         newex.ee_len = cpu_to_le16(map->m_len);
4448         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4449         if (err)
4450                 allocated = ext4_ext_get_actual_len(&newex);
4451         else
4452                 allocated = map->m_len;
4453
4454         /* allocate new block */
4455         ar.inode = inode;
4456         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4457         ar.logical = map->m_lblk;
4458         /*
4459          * We calculate the offset from the beginning of the cluster
4460          * for the logical block number, since when we allocate a
4461          * physical cluster, the physical block should start at the
4462          * same offset from the beginning of the cluster.  This is
4463          * needed so that future calls to get_implied_cluster_alloc()
4464          * work correctly.
4465          */
4466         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4467         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4468         ar.goal -= offset;
4469         ar.logical -= offset;
4470         if (S_ISREG(inode->i_mode))
4471                 ar.flags = EXT4_MB_HINT_DATA;
4472         else
4473                 /* disable in-core preallocation for non-regular files */
4474                 ar.flags = 0;
4475         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4476                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4477         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4478                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4479         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4480                 ar.flags |= EXT4_MB_USE_RESERVED;
4481         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4482         if (!newblock)
4483                 goto out2;
4484         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4485                   ar.goal, newblock, allocated);
4486         free_on_err = 1;
4487         allocated_clusters = ar.len;
4488         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4489         if (ar.len > allocated)
4490                 ar.len = allocated;
4491
4492 got_allocated_blocks:
4493         /* try to insert new extent into found leaf and return */
4494         ext4_ext_store_pblock(&newex, newblock + offset);
4495         newex.ee_len = cpu_to_le16(ar.len);
4496         /* Mark unwritten */
4497         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4498                 ext4_ext_mark_unwritten(&newex);
4499                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4500         }
4501
4502         err = 0;
4503         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4504                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4505                                          path, ar.len);
4506         if (!err)
4507                 err = ext4_ext_insert_extent(handle, inode, &path,
4508                                              &newex, flags);
4509
4510         if (err && free_on_err) {
4511                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4512                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4513                 /* free data blocks we just allocated */
4514                 /* not a good idea to call discard here directly,
4515                  * but otherwise we'd need to call it every free() */
4516                 ext4_discard_preallocations(inode);
4517                 ext4_free_blocks(handle, inode, NULL, newblock,
4518                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4519                 goto out2;
4520         }
4521
4522         /* previous routine could use block we allocated */
4523         newblock = ext4_ext_pblock(&newex);
4524         allocated = ext4_ext_get_actual_len(&newex);
4525         if (allocated > map->m_len)
4526                 allocated = map->m_len;
4527         map->m_flags |= EXT4_MAP_NEW;
4528
4529         /*
4530          * Update reserved blocks/metadata blocks after successful
4531          * block allocation which had been deferred till now.
4532          */
4533         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4534                 unsigned int reserved_clusters;
4535                 /*
4536                  * Check how many clusters we had reserved this allocated range
4537                  */
4538                 reserved_clusters = get_reserved_cluster_alloc(inode,
4539                                                 map->m_lblk, allocated);
4540                 if (!map_from_cluster) {
4541                         BUG_ON(allocated_clusters < reserved_clusters);
4542                         if (reserved_clusters < allocated_clusters) {
4543                                 struct ext4_inode_info *ei = EXT4_I(inode);
4544                                 int reservation = allocated_clusters -
4545                                                   reserved_clusters;
4546                                 /*
4547                                  * It seems we claimed few clusters outside of
4548                                  * the range of this allocation. We should give
4549                                  * it back to the reservation pool. This can
4550                                  * happen in the following case:
4551                                  *
4552                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4553                                  *   cluster has 4 blocks. Thus, the clusters
4554                                  *   are [0-3],[4-7],[8-11]...
4555                                  * * First comes delayed allocation write for
4556                                  *   logical blocks 10 & 11. Since there were no
4557                                  *   previous delayed allocated blocks in the
4558                                  *   range [8-11], we would reserve 1 cluster
4559                                  *   for this write.
4560                                  * * Next comes write for logical blocks 3 to 8.
4561                                  *   In this case, we will reserve 2 clusters
4562                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4563                                  *   that range has a delayed allocated blocks.
4564                                  *   Thus total reserved clusters now becomes 3.
4565                                  * * Now, during the delayed allocation writeout
4566                                  *   time, we will first write blocks [3-8] and
4567                                  *   allocate 3 clusters for writing these
4568                                  *   blocks. Also, we would claim all these
4569                                  *   three clusters above.
4570                                  * * Now when we come here to writeout the
4571                                  *   blocks [10-11], we would expect to claim
4572                                  *   the reservation of 1 cluster we had made
4573                                  *   (and we would claim it since there are no
4574                                  *   more delayed allocated blocks in the range
4575                                  *   [8-11]. But our reserved cluster count had
4576                                  *   already gone to 0.
4577                                  *
4578                                  *   Thus, at the step 4 above when we determine
4579                                  *   that there are still some unwritten delayed
4580                                  *   allocated blocks outside of our current
4581                                  *   block range, we should increment the
4582                                  *   reserved clusters count so that when the
4583                                  *   remaining blocks finally gets written, we
4584                                  *   could claim them.
4585                                  */
4586                                 dquot_reserve_block(inode,
4587                                                 EXT4_C2B(sbi, reservation));
4588                                 spin_lock(&ei->i_block_reservation_lock);
4589                                 ei->i_reserved_data_blocks += reservation;
4590                                 spin_unlock(&ei->i_block_reservation_lock);
4591                         }
4592                         /*
4593                          * We will claim quota for all newly allocated blocks.
4594                          * We're updating the reserved space *after* the
4595                          * correction above so we do not accidentally free
4596                          * all the metadata reservation because we might
4597                          * actually need it later on.
4598                          */
4599                         ext4_da_update_reserve_space(inode, allocated_clusters,
4600                                                         1);
4601                 }
4602         }
4603
4604         /*
4605          * Cache the extent and update transaction to commit on fdatasync only
4606          * when it is _not_ an unwritten extent.
4607          */
4608         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4609                 ext4_update_inode_fsync_trans(handle, inode, 1);
4610         else
4611                 ext4_update_inode_fsync_trans(handle, inode, 0);
4612 out:
4613         if (allocated > map->m_len)
4614                 allocated = map->m_len;
4615         ext4_ext_show_leaf(inode, path);
4616         map->m_flags |= EXT4_MAP_MAPPED;
4617         map->m_pblk = newblock;
4618         map->m_len = allocated;
4619 out2:
4620         ext4_ext_drop_refs(path);
4621         kfree(path);
4622
4623         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4624                                        err ? err : allocated);
4625         return err ? err : allocated;
4626 }
4627
4628 void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4629 {
4630         struct super_block *sb = inode->i_sb;
4631         ext4_lblk_t last_block;
4632         int err = 0;
4633
4634         /*
4635          * TODO: optimization is possible here.
4636          * Probably we need not scan at all,
4637          * because page truncation is enough.
4638          */
4639
4640         /* we have to know where to truncate from in crash case */
4641         EXT4_I(inode)->i_disksize = inode->i_size;
4642         ext4_mark_inode_dirty(handle, inode);
4643
4644         last_block = (inode->i_size + sb->s_blocksize - 1)
4645                         >> EXT4_BLOCK_SIZE_BITS(sb);
4646 retry:
4647         err = ext4_es_remove_extent(inode, last_block,
4648                                     EXT_MAX_BLOCKS - last_block);
4649         if (err == -ENOMEM) {
4650                 cond_resched();
4651                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4652                 goto retry;
4653         }
4654         if (err) {
4655                 ext4_std_error(inode->i_sb, err);
4656                 return;
4657         }
4658         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4659         ext4_std_error(inode->i_sb, err);
4660 }
4661
4662 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4663                                   ext4_lblk_t len, loff_t new_size,
4664                                   int flags, int mode)
4665 {
4666         struct inode *inode = file_inode(file);
4667         handle_t *handle;
4668         int ret = 0;
4669         int ret2 = 0;
4670         int retries = 0;
4671         int depth = 0;
4672         struct ext4_map_blocks map;
4673         unsigned int credits;
4674         loff_t epos;
4675
4676         map.m_lblk = offset;
4677         map.m_len = len;
4678         /*
4679          * Don't normalize the request if it can fit in one extent so
4680          * that it doesn't get unnecessarily split into multiple
4681          * extents.
4682          */
4683         if (len <= EXT_UNWRITTEN_MAX_LEN)
4684                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4685
4686         /*
4687          * credits to insert 1 extent into extent tree
4688          */
4689         credits = ext4_chunk_trans_blocks(inode, len);
4690         /*
4691          * We can only call ext_depth() on extent based inodes
4692          */
4693         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4694                 depth = ext_depth(inode);
4695         else
4696                 depth = -1;
4697
4698 retry:
4699         while (ret >= 0 && len) {
4700                 /*
4701                  * Recalculate credits when extent tree depth changes.
4702                  */
4703                 if (depth >= 0 && depth != ext_depth(inode)) {
4704                         credits = ext4_chunk_trans_blocks(inode, len);
4705                         depth = ext_depth(inode);
4706                 }
4707
4708                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4709                                             credits);
4710                 if (IS_ERR(handle)) {
4711                         ret = PTR_ERR(handle);
4712                         break;
4713                 }
4714                 ret = ext4_map_blocks(handle, inode, &map, flags);
4715                 if (ret <= 0) {
4716                         ext4_debug("inode #%lu: block %u: len %u: "
4717                                    "ext4_ext_map_blocks returned %d",
4718                                    inode->i_ino, map.m_lblk,
4719                                    map.m_len, ret);
4720                         ext4_mark_inode_dirty(handle, inode);
4721                         ret2 = ext4_journal_stop(handle);
4722                         break;
4723                 }
4724                 map.m_lblk += ret;
4725                 map.m_len = len = len - ret;
4726                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4727                 inode->i_ctime = ext4_current_time(inode);
4728                 if (new_size) {
4729                         if (epos > new_size)
4730                                 epos = new_size;
4731                         if (ext4_update_inode_size(inode, epos) & 0x1)
4732                                 inode->i_mtime = inode->i_ctime;
4733                 } else {
4734                         if (epos > inode->i_size)
4735                                 ext4_set_inode_flag(inode,
4736                                                     EXT4_INODE_EOFBLOCKS);
4737                 }
4738                 ext4_mark_inode_dirty(handle, inode);
4739                 ret2 = ext4_journal_stop(handle);
4740                 if (ret2)
4741                         break;
4742         }
4743         if (ret == -ENOSPC &&
4744                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4745                 ret = 0;
4746                 goto retry;
4747         }
4748
4749         return ret > 0 ? ret2 : ret;
4750 }
4751
4752 static long ext4_zero_range(struct file *file, loff_t offset,
4753                             loff_t len, int mode)
4754 {
4755         struct inode *inode = file_inode(file);
4756         handle_t *handle = NULL;
4757         unsigned int max_blocks;
4758         loff_t new_size = 0;
4759         int ret = 0;
4760         int flags;
4761         int credits;
4762         int partial_begin, partial_end;
4763         loff_t start, end;
4764         ext4_lblk_t lblk;
4765         unsigned int blkbits = inode->i_blkbits;
4766
4767         trace_ext4_zero_range(inode, offset, len, mode);
4768
4769         if (!S_ISREG(inode->i_mode))
4770                 return -EINVAL;
4771
4772         /* Call ext4_force_commit to flush all data in case of data=journal. */
4773         if (ext4_should_journal_data(inode)) {
4774                 ret = ext4_force_commit(inode->i_sb);
4775                 if (ret)
4776                         return ret;
4777         }
4778
4779         /*
4780          * Round up offset. This is not fallocate, we neet to zero out
4781          * blocks, so convert interior block aligned part of the range to
4782          * unwritten and possibly manually zero out unaligned parts of the
4783          * range.
4784          */
4785         start = round_up(offset, 1 << blkbits);
4786         end = round_down((offset + len), 1 << blkbits);
4787
4788         if (start < offset || end > offset + len)
4789                 return -EINVAL;
4790         partial_begin = offset & ((1 << blkbits) - 1);
4791         partial_end = (offset + len) & ((1 << blkbits) - 1);
4792
4793         lblk = start >> blkbits;
4794         max_blocks = (end >> blkbits);
4795         if (max_blocks < lblk)
4796                 max_blocks = 0;
4797         else
4798                 max_blocks -= lblk;
4799
4800         inode_lock(inode);
4801
4802         /*
4803          * Indirect files do not support unwritten extnets
4804          */
4805         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4806                 ret = -EOPNOTSUPP;
4807                 goto out_mutex;
4808         }
4809
4810         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4811              offset + len > i_size_read(inode)) {
4812                 new_size = offset + len;
4813                 ret = inode_newsize_ok(inode, new_size);
4814                 if (ret)
4815                         goto out_mutex;
4816         }
4817
4818         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4819         if (mode & FALLOC_FL_KEEP_SIZE)
4820                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4821
4822         /* Wait all existing dio workers, newcomers will block on i_mutex */
4823         ext4_inode_block_unlocked_dio(inode);
4824         inode_dio_wait(inode);
4825
4826         /* Preallocate the range including the unaligned edges */
4827         if (partial_begin || partial_end) {
4828                 ret = ext4_alloc_file_blocks(file,
4829                                 round_down(offset, 1 << blkbits) >> blkbits,
4830                                 (round_up((offset + len), 1 << blkbits) -
4831                                  round_down(offset, 1 << blkbits)) >> blkbits,
4832                                 new_size, flags, mode);
4833                 if (ret)
4834                         goto out_dio;
4835
4836         }
4837
4838         /* Zero range excluding the unaligned edges */
4839         if (max_blocks > 0) {
4840                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4841                           EXT4_EX_NOCACHE);
4842
4843                 /*
4844                  * Prevent page faults from reinstantiating pages we have
4845                  * released from page cache.
4846                  */
4847                 down_write(&EXT4_I(inode)->i_mmap_sem);
4848                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4849                 if (ret) {
4850                         up_write(&EXT4_I(inode)->i_mmap_sem);
4851                         goto out_dio;
4852                 }
4853                 /* Now release the pages and zero block aligned part of pages */
4854                 truncate_pagecache_range(inode, start, end - 1);
4855                 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4856
4857                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4858                                              flags, mode);
4859                 up_write(&EXT4_I(inode)->i_mmap_sem);
4860                 if (ret)
4861                         goto out_dio;
4862         }
4863         if (!partial_begin && !partial_end)
4864                 goto out_dio;
4865
4866         /*
4867          * In worst case we have to writeout two nonadjacent unwritten
4868          * blocks and update the inode
4869          */
4870         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4871         if (ext4_should_journal_data(inode))
4872                 credits += 2;
4873         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4874         if (IS_ERR(handle)) {
4875                 ret = PTR_ERR(handle);
4876                 ext4_std_error(inode->i_sb, ret);
4877                 goto out_dio;
4878         }
4879
4880         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4881         if (new_size) {
4882                 ext4_update_inode_size(inode, new_size);
4883         } else {
4884                 /*
4885                 * Mark that we allocate beyond EOF so the subsequent truncate
4886                 * can proceed even if the new size is the same as i_size.
4887                 */
4888                 if ((offset + len) > i_size_read(inode))
4889                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4890         }
4891         ext4_mark_inode_dirty(handle, inode);
4892
4893         /* Zero out partial block at the edges of the range */
4894         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4895
4896         if (file->f_flags & O_SYNC)
4897                 ext4_handle_sync(handle);
4898
4899         ext4_journal_stop(handle);
4900 out_dio:
4901         ext4_inode_resume_unlocked_dio(inode);
4902 out_mutex:
4903         inode_unlock(inode);
4904         return ret;
4905 }
4906
4907 /*
4908  * preallocate space for a file. This implements ext4's fallocate file
4909  * operation, which gets called from sys_fallocate system call.
4910  * For block-mapped files, posix_fallocate should fall back to the method
4911  * of writing zeroes to the required new blocks (the same behavior which is
4912  * expected for file systems which do not support fallocate() system call).
4913  */
4914 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4915 {
4916         struct inode *inode = file_inode(file);
4917         loff_t new_size = 0;
4918         unsigned int max_blocks;
4919         int ret = 0;
4920         int flags;
4921         ext4_lblk_t lblk;
4922         unsigned int blkbits = inode->i_blkbits;
4923
4924         /*
4925          * Encrypted inodes can't handle collapse range or insert
4926          * range since we would need to re-encrypt blocks with a
4927          * different IV or XTS tweak (which are based on the logical
4928          * block number).
4929          *
4930          * XXX It's not clear why zero range isn't working, but we'll
4931          * leave it disabled for encrypted inodes for now.  This is a
4932          * bug we should fix....
4933          */
4934         if (ext4_encrypted_inode(inode) &&
4935             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4936                      FALLOC_FL_ZERO_RANGE)))
4937                 return -EOPNOTSUPP;
4938
4939         /* Return error if mode is not supported */
4940         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4941                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4942                      FALLOC_FL_INSERT_RANGE))
4943                 return -EOPNOTSUPP;
4944
4945         if (mode & FALLOC_FL_PUNCH_HOLE)
4946                 return ext4_punch_hole(inode, offset, len);
4947
4948         ret = ext4_convert_inline_data(inode);
4949         if (ret)
4950                 return ret;
4951
4952         if (mode & FALLOC_FL_COLLAPSE_RANGE)
4953                 return ext4_collapse_range(inode, offset, len);
4954
4955         if (mode & FALLOC_FL_INSERT_RANGE)
4956                 return ext4_insert_range(inode, offset, len);
4957
4958         if (mode & FALLOC_FL_ZERO_RANGE)
4959                 return ext4_zero_range(file, offset, len, mode);
4960
4961         trace_ext4_fallocate_enter(inode, offset, len, mode);
4962         lblk = offset >> blkbits;
4963         /*
4964          * We can't just convert len to max_blocks because
4965          * If blocksize = 4096 offset = 3072 and len = 2048
4966          */
4967         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4968                 - lblk;
4969
4970         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4971         if (mode & FALLOC_FL_KEEP_SIZE)
4972                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4973
4974         inode_lock(inode);
4975
4976         /*
4977          * We only support preallocation for extent-based files only
4978          */
4979         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4980                 ret = -EOPNOTSUPP;
4981                 goto out;
4982         }
4983
4984         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4985              offset + len > i_size_read(inode)) {
4986                 new_size = offset + len;
4987                 ret = inode_newsize_ok(inode, new_size);
4988                 if (ret)
4989                         goto out;
4990         }
4991
4992         /* Wait all existing dio workers, newcomers will block on i_mutex */
4993         ext4_inode_block_unlocked_dio(inode);
4994         inode_dio_wait(inode);
4995
4996         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4997                                      flags, mode);
4998         ext4_inode_resume_unlocked_dio(inode);
4999         if (ret)
5000                 goto out;
5001
5002         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
5003                 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
5004                                                 EXT4_I(inode)->i_sync_tid);
5005         }
5006 out:
5007         inode_unlock(inode);
5008         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
5009         return ret;
5010 }
5011
5012 /*
5013  * This function convert a range of blocks to written extents
5014  * The caller of this function will pass the start offset and the size.
5015  * all unwritten extents within this range will be converted to
5016  * written extents.
5017  *
5018  * This function is called from the direct IO end io call back
5019  * function, to convert the fallocated extents after IO is completed.
5020  * Returns 0 on success.
5021  */
5022 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
5023                                    loff_t offset, ssize_t len)
5024 {
5025         unsigned int max_blocks;
5026         int ret = 0;
5027         int ret2 = 0;
5028         struct ext4_map_blocks map;
5029         unsigned int credits, blkbits = inode->i_blkbits;
5030
5031         map.m_lblk = offset >> blkbits;
5032         /*
5033          * We can't just convert len to max_blocks because
5034          * If blocksize = 4096 offset = 3072 and len = 2048
5035          */
5036         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
5037                       map.m_lblk);
5038         /*
5039          * This is somewhat ugly but the idea is clear: When transaction is
5040          * reserved, everything goes into it. Otherwise we rather start several
5041          * smaller transactions for conversion of each extent separately.
5042          */
5043         if (handle) {
5044                 handle = ext4_journal_start_reserved(handle,
5045                                                      EXT4_HT_EXT_CONVERT);
5046                 if (IS_ERR(handle))
5047                         return PTR_ERR(handle);
5048                 credits = 0;
5049         } else {
5050                 /*
5051                  * credits to insert 1 extent into extent tree
5052                  */
5053                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5054         }
5055         while (ret >= 0 && ret < max_blocks) {
5056                 map.m_lblk += ret;
5057                 map.m_len = (max_blocks -= ret);
5058                 if (credits) {
5059                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5060                                                     credits);
5061                         if (IS_ERR(handle)) {
5062                                 ret = PTR_ERR(handle);
5063                                 break;
5064                         }
5065                 }
5066                 ret = ext4_map_blocks(handle, inode, &map,
5067                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5068                 if (ret <= 0)
5069                         ext4_warning(inode->i_sb,
5070                                      "inode #%lu: block %u: len %u: "
5071                                      "ext4_ext_map_blocks returned %d",
5072                                      inode->i_ino, map.m_lblk,
5073                                      map.m_len, ret);
5074                 ext4_mark_inode_dirty(handle, inode);
5075                 if (credits)
5076                         ret2 = ext4_journal_stop(handle);
5077                 if (ret <= 0 || ret2)
5078                         break;
5079         }
5080         if (!credits)
5081                 ret2 = ext4_journal_stop(handle);
5082         return ret > 0 ? ret2 : ret;
5083 }
5084
5085 /*
5086  * If newes is not existing extent (newes->ec_pblk equals zero) find
5087  * delayed extent at start of newes and update newes accordingly and
5088  * return start of the next delayed extent.
5089  *
5090  * If newes is existing extent (newes->ec_pblk is not equal zero)
5091  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5092  * extent found. Leave newes unmodified.
5093  */
5094 static int ext4_find_delayed_extent(struct inode *inode,
5095                                     struct extent_status *newes)
5096 {
5097         struct extent_status es;
5098         ext4_lblk_t block, next_del;
5099
5100         if (newes->es_pblk == 0) {
5101                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5102                                 newes->es_lblk + newes->es_len - 1, &es);
5103
5104                 /*
5105                  * No extent in extent-tree contains block @newes->es_pblk,
5106                  * then the block may stay in 1)a hole or 2)delayed-extent.
5107                  */
5108                 if (es.es_len == 0)
5109                         /* A hole found. */
5110                         return 0;
5111
5112                 if (es.es_lblk > newes->es_lblk) {
5113                         /* A hole found. */
5114                         newes->es_len = min(es.es_lblk - newes->es_lblk,
5115                                             newes->es_len);
5116                         return 0;
5117                 }
5118
5119                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5120         }
5121
5122         block = newes->es_lblk + newes->es_len;
5123         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5124         if (es.es_len == 0)
5125                 next_del = EXT_MAX_BLOCKS;
5126         else
5127                 next_del = es.es_lblk;
5128
5129         return next_del;
5130 }
5131 /* fiemap flags we can handle specified here */
5132 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5133
5134 static int ext4_xattr_fiemap(struct inode *inode,
5135                                 struct fiemap_extent_info *fieinfo)
5136 {
5137         __u64 physical = 0;
5138         __u64 length;
5139         __u32 flags = FIEMAP_EXTENT_LAST;
5140         int blockbits = inode->i_sb->s_blocksize_bits;
5141         int error = 0;
5142
5143         /* in-inode? */
5144         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5145                 struct ext4_iloc iloc;
5146                 int offset;     /* offset of xattr in inode */
5147
5148                 error = ext4_get_inode_loc(inode, &iloc);
5149                 if (error)
5150                         return error;
5151                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5152                 offset = EXT4_GOOD_OLD_INODE_SIZE +
5153                                 EXT4_I(inode)->i_extra_isize;
5154                 physical += offset;
5155                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5156                 flags |= FIEMAP_EXTENT_DATA_INLINE;
5157                 brelse(iloc.bh);
5158         } else { /* external block */
5159                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5160                 length = inode->i_sb->s_blocksize;
5161         }
5162
5163         if (physical)
5164                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5165                                                 length, flags);
5166         return (error < 0 ? error : 0);
5167 }
5168
5169 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5170                 __u64 start, __u64 len)
5171 {
5172         ext4_lblk_t start_blk;
5173         int error = 0;
5174
5175         if (ext4_has_inline_data(inode)) {
5176                 int has_inline = 1;
5177
5178                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5179                                                 start, len);
5180
5181                 if (has_inline)
5182                         return error;
5183         }
5184
5185         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5186                 error = ext4_ext_precache(inode);
5187                 if (error)
5188                         return error;
5189         }
5190
5191         /* fallback to generic here if not in extents fmt */
5192         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5193                 return generic_block_fiemap(inode, fieinfo, start, len,
5194                         ext4_get_block);
5195
5196         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5197                 return -EBADR;
5198
5199         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5200                 error = ext4_xattr_fiemap(inode, fieinfo);
5201         } else {
5202                 ext4_lblk_t len_blks;
5203                 __u64 last_blk;
5204
5205                 start_blk = start >> inode->i_sb->s_blocksize_bits;
5206                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5207                 if (last_blk >= EXT_MAX_BLOCKS)
5208                         last_blk = EXT_MAX_BLOCKS-1;
5209                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5210
5211                 /*
5212                  * Walk the extent tree gathering extent information
5213                  * and pushing extents back to the user.
5214                  */
5215                 error = ext4_fill_fiemap_extents(inode, start_blk,
5216                                                  len_blks, fieinfo);
5217         }
5218         return error;
5219 }
5220
5221 /*
5222  * ext4_access_path:
5223  * Function to access the path buffer for marking it dirty.
5224  * It also checks if there are sufficient credits left in the journal handle
5225  * to update path.
5226  */
5227 static int
5228 ext4_access_path(handle_t *handle, struct inode *inode,
5229                 struct ext4_ext_path *path)
5230 {
5231         int credits, err;
5232
5233         if (!ext4_handle_valid(handle))
5234                 return 0;
5235
5236         /*
5237          * Check if need to extend journal credits
5238          * 3 for leaf, sb, and inode plus 2 (bmap and group
5239          * descriptor) for each block group; assume two block
5240          * groups
5241          */
5242         if (handle->h_buffer_credits < 7) {
5243                 credits = ext4_writepage_trans_blocks(inode);
5244                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5245                 /* EAGAIN is success */
5246                 if (err && err != -EAGAIN)
5247                         return err;
5248         }
5249
5250         err = ext4_ext_get_access(handle, inode, path);
5251         return err;
5252 }
5253
5254 /*
5255  * ext4_ext_shift_path_extents:
5256  * Shift the extents of a path structure lying between path[depth].p_ext
5257  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5258  * if it is right shift or left shift operation.
5259  */
5260 static int
5261 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5262                             struct inode *inode, handle_t *handle,
5263                             enum SHIFT_DIRECTION SHIFT)
5264 {
5265         int depth, err = 0;
5266         struct ext4_extent *ex_start, *ex_last;
5267         bool update = 0;
5268         depth = path->p_depth;
5269
5270         while (depth >= 0) {
5271                 if (depth == path->p_depth) {
5272                         ex_start = path[depth].p_ext;
5273                         if (!ex_start)
5274                                 return -EFSCORRUPTED;
5275
5276                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5277
5278                         err = ext4_access_path(handle, inode, path + depth);
5279                         if (err)
5280                                 goto out;
5281
5282                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5283                                 update = 1;
5284
5285                         while (ex_start <= ex_last) {
5286                                 if (SHIFT == SHIFT_LEFT) {
5287                                         le32_add_cpu(&ex_start->ee_block,
5288                                                 -shift);
5289                                         /* Try to merge to the left. */
5290                                         if ((ex_start >
5291                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5292                                             &&
5293                                             ext4_ext_try_to_merge_right(inode,
5294                                             path, ex_start - 1))
5295                                                 ex_last--;
5296                                         else
5297                                                 ex_start++;
5298                                 } else {
5299                                         le32_add_cpu(&ex_last->ee_block, shift);
5300                                         ext4_ext_try_to_merge_right(inode, path,
5301                                                 ex_last);
5302                                         ex_last--;
5303                                 }
5304                         }
5305                         err = ext4_ext_dirty(handle, inode, path + depth);
5306                         if (err)
5307                                 goto out;
5308
5309                         if (--depth < 0 || !update)
5310                                 break;
5311                 }
5312
5313                 /* Update index too */
5314                 err = ext4_access_path(handle, inode, path + depth);
5315                 if (err)
5316                         goto out;
5317
5318                 if (SHIFT == SHIFT_LEFT)
5319                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5320                 else
5321                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5322                 err = ext4_ext_dirty(handle, inode, path + depth);
5323                 if (err)
5324                         goto out;
5325
5326                 /* we are done if current index is not a starting index */
5327                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5328                         break;
5329
5330                 depth--;
5331         }
5332
5333 out:
5334         return err;
5335 }
5336
5337 /*
5338  * ext4_ext_shift_extents:
5339  * All the extents which lies in the range from @start to the last allocated
5340  * block for the @inode are shifted either towards left or right (depending
5341  * upon @SHIFT) by @shift blocks.
5342  * On success, 0 is returned, error otherwise.
5343  */
5344 static int
5345 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5346                        ext4_lblk_t start, ext4_lblk_t shift,
5347                        enum SHIFT_DIRECTION SHIFT)
5348 {
5349         struct ext4_ext_path *path;
5350         int ret = 0, depth;
5351         struct ext4_extent *extent;
5352         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5353
5354         /* Let path point to the last extent */
5355         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
5356         if (IS_ERR(path))
5357                 return PTR_ERR(path);
5358
5359         depth = path->p_depth;
5360         extent = path[depth].p_ext;
5361         if (!extent)
5362                 goto out;
5363
5364         stop = le32_to_cpu(extent->ee_block) +
5365                         ext4_ext_get_actual_len(extent);
5366
5367        /*
5368          * In case of left shift, Don't start shifting extents until we make
5369          * sure the hole is big enough to accommodate the shift.
5370         */
5371         if (SHIFT == SHIFT_LEFT) {
5372                 path = ext4_find_extent(inode, start - 1, &path, 0);
5373                 if (IS_ERR(path))
5374                         return PTR_ERR(path);
5375                 depth = path->p_depth;
5376                 extent =  path[depth].p_ext;
5377                 if (extent) {
5378                         ex_start = le32_to_cpu(extent->ee_block);
5379                         ex_end = le32_to_cpu(extent->ee_block) +
5380                                 ext4_ext_get_actual_len(extent);
5381                 } else {
5382                         ex_start = 0;
5383                         ex_end = 0;
5384                 }
5385
5386                 if ((start == ex_start && shift > ex_start) ||
5387                     (shift > start - ex_end)) {
5388                         ext4_ext_drop_refs(path);
5389                         kfree(path);
5390                         return -EINVAL;
5391                 }
5392         }
5393
5394         /*
5395          * In case of left shift, iterator points to start and it is increased
5396          * till we reach stop. In case of right shift, iterator points to stop
5397          * and it is decreased till we reach start.
5398          */
5399         if (SHIFT == SHIFT_LEFT)
5400                 iterator = &start;
5401         else
5402                 iterator = &stop;
5403
5404         /* Its safe to start updating extents */
5405         while (start < stop) {
5406                 path = ext4_find_extent(inode, *iterator, &path, 0);
5407                 if (IS_ERR(path))
5408                         return PTR_ERR(path);
5409                 depth = path->p_depth;
5410                 extent = path[depth].p_ext;
5411                 if (!extent) {
5412                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5413                                          (unsigned long) *iterator);
5414                         return -EFSCORRUPTED;
5415                 }
5416                 if (SHIFT == SHIFT_LEFT && *iterator >
5417                     le32_to_cpu(extent->ee_block)) {
5418                         /* Hole, move to the next extent */
5419                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5420                                 path[depth].p_ext++;
5421                         } else {
5422                                 *iterator = ext4_ext_next_allocated_block(path);
5423                                 continue;
5424                         }
5425                 }
5426
5427                 if (SHIFT == SHIFT_LEFT) {
5428                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5429                         *iterator = le32_to_cpu(extent->ee_block) +
5430                                         ext4_ext_get_actual_len(extent);
5431                 } else {
5432                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5433                         *iterator =  le32_to_cpu(extent->ee_block) > 0 ?
5434                                 le32_to_cpu(extent->ee_block) - 1 : 0;
5435                         /* Update path extent in case we need to stop */
5436                         while (le32_to_cpu(extent->ee_block) < start)
5437                                 extent++;
5438                         path[depth].p_ext = extent;
5439                 }
5440                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5441                                 handle, SHIFT);
5442                 if (ret)
5443                         break;
5444         }
5445 out:
5446         ext4_ext_drop_refs(path);
5447         kfree(path);
5448         return ret;
5449 }
5450
5451 /*
5452  * ext4_collapse_range:
5453  * This implements the fallocate's collapse range functionality for ext4
5454  * Returns: 0 and non-zero on error.
5455  */
5456 int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5457 {
5458         struct super_block *sb = inode->i_sb;
5459         ext4_lblk_t punch_start, punch_stop;
5460         handle_t *handle;
5461         unsigned int credits;
5462         loff_t new_size, ioffset;
5463         int ret;
5464
5465         /*
5466          * We need to test this early because xfstests assumes that a
5467          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5468          * system does not support collapse range.
5469          */
5470         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5471                 return -EOPNOTSUPP;
5472
5473         /* Collapse range works only on fs block size aligned offsets. */
5474         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5475             len & (EXT4_CLUSTER_SIZE(sb) - 1))
5476                 return -EINVAL;
5477
5478         if (!S_ISREG(inode->i_mode))
5479                 return -EINVAL;
5480
5481         trace_ext4_collapse_range(inode, offset, len);
5482
5483         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5484         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5485
5486         /* Call ext4_force_commit to flush all data in case of data=journal. */
5487         if (ext4_should_journal_data(inode)) {
5488                 ret = ext4_force_commit(inode->i_sb);
5489                 if (ret)
5490                         return ret;
5491         }
5492
5493         inode_lock(inode);
5494         /*
5495          * There is no need to overlap collapse range with EOF, in which case
5496          * it is effectively a truncate operation
5497          */
5498         if (offset + len >= i_size_read(inode)) {
5499                 ret = -EINVAL;
5500                 goto out_mutex;
5501         }
5502
5503         /* Currently just for extent based files */
5504         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5505                 ret = -EOPNOTSUPP;
5506                 goto out_mutex;
5507         }
5508
5509         /* Wait for existing dio to complete */
5510         ext4_inode_block_unlocked_dio(inode);
5511         inode_dio_wait(inode);
5512
5513         /*
5514          * Prevent page faults from reinstantiating pages we have released from
5515          * page cache.
5516          */
5517         down_write(&EXT4_I(inode)->i_mmap_sem);
5518         /*
5519          * Need to round down offset to be aligned with page size boundary
5520          * for page size > block size.
5521          */
5522         ioffset = round_down(offset, PAGE_SIZE);
5523         /*
5524          * Write tail of the last page before removed range since it will get
5525          * removed from the page cache below.
5526          */
5527         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5528         if (ret)
5529                 goto out_mmap;
5530         /*
5531          * Write data that will be shifted to preserve them when discarding
5532          * page cache below. We are also protected from pages becoming dirty
5533          * by i_mmap_sem.
5534          */
5535         ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5536                                            LLONG_MAX);
5537         if (ret)
5538                 goto out_mmap;
5539         truncate_pagecache(inode, ioffset);
5540
5541         credits = ext4_writepage_trans_blocks(inode);
5542         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5543         if (IS_ERR(handle)) {
5544                 ret = PTR_ERR(handle);
5545                 goto out_mmap;
5546         }
5547
5548         down_write(&EXT4_I(inode)->i_data_sem);
5549         ext4_discard_preallocations(inode);
5550
5551         ret = ext4_es_remove_extent(inode, punch_start,
5552                                     EXT_MAX_BLOCKS - punch_start);
5553         if (ret) {
5554                 up_write(&EXT4_I(inode)->i_data_sem);
5555                 goto out_stop;
5556         }
5557
5558         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5559         if (ret) {
5560                 up_write(&EXT4_I(inode)->i_data_sem);
5561                 goto out_stop;
5562         }
5563         ext4_discard_preallocations(inode);
5564
5565         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5566                                      punch_stop - punch_start, SHIFT_LEFT);
5567         if (ret) {
5568                 up_write(&EXT4_I(inode)->i_data_sem);
5569                 goto out_stop;
5570         }
5571
5572         new_size = i_size_read(inode) - len;
5573         i_size_write(inode, new_size);
5574         EXT4_I(inode)->i_disksize = new_size;
5575
5576         up_write(&EXT4_I(inode)->i_data_sem);
5577         if (IS_SYNC(inode))
5578                 ext4_handle_sync(handle);
5579         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5580         ext4_mark_inode_dirty(handle, inode);
5581
5582 out_stop:
5583         ext4_journal_stop(handle);
5584 out_mmap:
5585         up_write(&EXT4_I(inode)->i_mmap_sem);
5586         ext4_inode_resume_unlocked_dio(inode);
5587 out_mutex:
5588         inode_unlock(inode);
5589         return ret;
5590 }
5591
5592 /*
5593  * ext4_insert_range:
5594  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5595  * The data blocks starting from @offset to the EOF are shifted by @len
5596  * towards right to create a hole in the @inode. Inode size is increased
5597  * by len bytes.
5598  * Returns 0 on success, error otherwise.
5599  */
5600 int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5601 {
5602         struct super_block *sb = inode->i_sb;
5603         handle_t *handle;
5604         struct ext4_ext_path *path;
5605         struct ext4_extent *extent;
5606         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5607         unsigned int credits, ee_len;
5608         int ret = 0, depth, split_flag = 0;
5609         loff_t ioffset;
5610
5611         /*
5612          * We need to test this early because xfstests assumes that an
5613          * insert range of (0, 1) will return EOPNOTSUPP if the file
5614          * system does not support insert range.
5615          */
5616         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5617                 return -EOPNOTSUPP;
5618
5619         /* Insert range works only on fs block size aligned offsets. */
5620         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5621                         len & (EXT4_CLUSTER_SIZE(sb) - 1))
5622                 return -EINVAL;
5623
5624         if (!S_ISREG(inode->i_mode))
5625                 return -EOPNOTSUPP;
5626
5627         trace_ext4_insert_range(inode, offset, len);
5628
5629         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5630         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5631
5632         /* Call ext4_force_commit to flush all data in case of data=journal */
5633         if (ext4_should_journal_data(inode)) {
5634                 ret = ext4_force_commit(inode->i_sb);
5635                 if (ret)
5636                         return ret;
5637         }
5638
5639         inode_lock(inode);
5640         /* Currently just for extent based files */
5641         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5642                 ret = -EOPNOTSUPP;
5643                 goto out_mutex;
5644         }
5645
5646         /* Check for wrap through zero */
5647         if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5648                 ret = -EFBIG;
5649                 goto out_mutex;
5650         }
5651
5652         /* Offset should be less than i_size */
5653         if (offset >= i_size_read(inode)) {
5654                 ret = -EINVAL;
5655                 goto out_mutex;
5656         }
5657
5658         /* Wait for existing dio to complete */
5659         ext4_inode_block_unlocked_dio(inode);
5660         inode_dio_wait(inode);
5661
5662         /*
5663          * Prevent page faults from reinstantiating pages we have released from
5664          * page cache.
5665          */
5666         down_write(&EXT4_I(inode)->i_mmap_sem);
5667         /*
5668          * Need to round down to align start offset to page size boundary
5669          * for page size > block size.
5670          */
5671         ioffset = round_down(offset, PAGE_SIZE);
5672         /* Write out all dirty pages */
5673         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5674                         LLONG_MAX);
5675         if (ret)
5676                 goto out_mmap;
5677         truncate_pagecache(inode, ioffset);
5678
5679         credits = ext4_writepage_trans_blocks(inode);
5680         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5681         if (IS_ERR(handle)) {
5682                 ret = PTR_ERR(handle);
5683                 goto out_mmap;
5684         }
5685
5686         /* Expand file to avoid data loss if there is error while shifting */
5687         inode->i_size += len;
5688         EXT4_I(inode)->i_disksize += len;
5689         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5690         ret = ext4_mark_inode_dirty(handle, inode);
5691         if (ret)
5692                 goto out_stop;
5693
5694         down_write(&EXT4_I(inode)->i_data_sem);
5695         ext4_discard_preallocations(inode);
5696
5697         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5698         if (IS_ERR(path)) {
5699                 up_write(&EXT4_I(inode)->i_data_sem);
5700                 goto out_stop;
5701         }
5702
5703         depth = ext_depth(inode);
5704         extent = path[depth].p_ext;
5705         if (extent) {
5706                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5707                 ee_len = ext4_ext_get_actual_len(extent);
5708
5709                 /*
5710                  * If offset_lblk is not the starting block of extent, split
5711                  * the extent @offset_lblk
5712                  */
5713                 if ((offset_lblk > ee_start_lblk) &&
5714                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5715                         if (ext4_ext_is_unwritten(extent))
5716                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5717                                         EXT4_EXT_MARK_UNWRIT2;
5718                         ret = ext4_split_extent_at(handle, inode, &path,
5719                                         offset_lblk, split_flag,
5720                                         EXT4_EX_NOCACHE |
5721                                         EXT4_GET_BLOCKS_PRE_IO |
5722                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5723                 }
5724
5725                 ext4_ext_drop_refs(path);
5726                 kfree(path);
5727                 if (ret < 0) {
5728                         up_write(&EXT4_I(inode)->i_data_sem);
5729                         goto out_stop;
5730                 }
5731         }
5732
5733         ret = ext4_es_remove_extent(inode, offset_lblk,
5734                         EXT_MAX_BLOCKS - offset_lblk);
5735         if (ret) {
5736                 up_write(&EXT4_I(inode)->i_data_sem);
5737                 goto out_stop;
5738         }
5739
5740         /*
5741          * if offset_lblk lies in a hole which is at start of file, use
5742          * ee_start_lblk to shift extents
5743          */
5744         ret = ext4_ext_shift_extents(inode, handle,
5745                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5746                 len_lblk, SHIFT_RIGHT);
5747
5748         up_write(&EXT4_I(inode)->i_data_sem);
5749         if (IS_SYNC(inode))
5750                 ext4_handle_sync(handle);
5751
5752 out_stop:
5753         ext4_journal_stop(handle);
5754 out_mmap:
5755         up_write(&EXT4_I(inode)->i_mmap_sem);
5756         ext4_inode_resume_unlocked_dio(inode);
5757 out_mutex:
5758         inode_unlock(inode);
5759         return ret;
5760 }
5761
5762 /**
5763  * ext4_swap_extents - Swap extents between two inodes
5764  *
5765  * @inode1:     First inode
5766  * @inode2:     Second inode
5767  * @lblk1:      Start block for first inode
5768  * @lblk2:      Start block for second inode
5769  * @count:      Number of blocks to swap
5770  * @mark_unwritten: Mark second inode's extents as unwritten after swap
5771  * @erp:        Pointer to save error value
5772  *
5773  * This helper routine does exactly what is promise "swap extents". All other
5774  * stuff such as page-cache locking consistency, bh mapping consistency or
5775  * extent's data copying must be performed by caller.
5776  * Locking:
5777  *              i_mutex is held for both inodes
5778  *              i_data_sem is locked for write for both inodes
5779  * Assumptions:
5780  *              All pages from requested range are locked for both inodes
5781  */
5782 int
5783 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5784                      struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5785                   ext4_lblk_t count, int unwritten, int *erp)
5786 {
5787         struct ext4_ext_path *path1 = NULL;
5788         struct ext4_ext_path *path2 = NULL;
5789         int replaced_count = 0;
5790
5791         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5792         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5793         BUG_ON(!inode_is_locked(inode1));
5794         BUG_ON(!inode_is_locked(inode2));
5795
5796         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5797         if (unlikely(*erp))
5798                 return 0;
5799         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5800         if (unlikely(*erp))
5801                 return 0;
5802
5803         while (count) {
5804                 struct ext4_extent *ex1, *ex2, tmp_ex;
5805                 ext4_lblk_t e1_blk, e2_blk;
5806                 int e1_len, e2_len, len;
5807                 int split = 0;
5808
5809                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5810                 if (IS_ERR(path1)) {
5811                         *erp = PTR_ERR(path1);
5812                         path1 = NULL;
5813                 finish:
5814                         count = 0;
5815                         goto repeat;
5816                 }
5817                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5818                 if (IS_ERR(path2)) {
5819                         *erp = PTR_ERR(path2);
5820                         path2 = NULL;
5821                         goto finish;
5822                 }
5823                 ex1 = path1[path1->p_depth].p_ext;
5824                 ex2 = path2[path2->p_depth].p_ext;
5825                 /* Do we have somthing to swap ? */
5826                 if (unlikely(!ex2 || !ex1))
5827                         goto finish;
5828
5829                 e1_blk = le32_to_cpu(ex1->ee_block);
5830                 e2_blk = le32_to_cpu(ex2->ee_block);
5831                 e1_len = ext4_ext_get_actual_len(ex1);
5832                 e2_len = ext4_ext_get_actual_len(ex2);
5833
5834                 /* Hole handling */
5835                 if (!in_range(lblk1, e1_blk, e1_len) ||
5836                     !in_range(lblk2, e2_blk, e2_len)) {
5837                         ext4_lblk_t next1, next2;
5838
5839                         /* if hole after extent, then go to next extent */
5840                         next1 = ext4_ext_next_allocated_block(path1);
5841                         next2 = ext4_ext_next_allocated_block(path2);
5842                         /* If hole before extent, then shift to that extent */
5843                         if (e1_blk > lblk1)
5844                                 next1 = e1_blk;
5845                         if (e2_blk > lblk2)
5846                                 next2 = e1_blk;
5847                         /* Do we have something to swap */
5848                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5849                                 goto finish;
5850                         /* Move to the rightest boundary */
5851                         len = next1 - lblk1;
5852                         if (len < next2 - lblk2)
5853                                 len = next2 - lblk2;
5854                         if (len > count)
5855                                 len = count;
5856                         lblk1 += len;
5857                         lblk2 += len;
5858                         count -= len;
5859                         goto repeat;
5860                 }
5861
5862                 /* Prepare left boundary */
5863                 if (e1_blk < lblk1) {
5864                         split = 1;
5865                         *erp = ext4_force_split_extent_at(handle, inode1,
5866                                                 &path1, lblk1, 0);
5867                         if (unlikely(*erp))
5868                                 goto finish;
5869                 }
5870                 if (e2_blk < lblk2) {
5871                         split = 1;
5872                         *erp = ext4_force_split_extent_at(handle, inode2,
5873                                                 &path2,  lblk2, 0);
5874                         if (unlikely(*erp))
5875                                 goto finish;
5876                 }
5877                 /* ext4_split_extent_at() may result in leaf extent split,
5878                  * path must to be revalidated. */
5879                 if (split)
5880                         goto repeat;
5881
5882                 /* Prepare right boundary */
5883                 len = count;
5884                 if (len > e1_blk + e1_len - lblk1)
5885                         len = e1_blk + e1_len - lblk1;
5886                 if (len > e2_blk + e2_len - lblk2)
5887                         len = e2_blk + e2_len - lblk2;
5888
5889                 if (len != e1_len) {
5890                         split = 1;
5891                         *erp = ext4_force_split_extent_at(handle, inode1,
5892                                                 &path1, lblk1 + len, 0);
5893                         if (unlikely(*erp))
5894                                 goto finish;
5895                 }
5896                 if (len != e2_len) {
5897                         split = 1;
5898                         *erp = ext4_force_split_extent_at(handle, inode2,
5899                                                 &path2, lblk2 + len, 0);
5900                         if (*erp)
5901                                 goto finish;
5902                 }
5903                 /* ext4_split_extent_at() may result in leaf extent split,
5904                  * path must to be revalidated. */
5905                 if (split)
5906                         goto repeat;
5907
5908                 BUG_ON(e2_len != e1_len);
5909                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5910                 if (unlikely(*erp))
5911                         goto finish;
5912                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5913                 if (unlikely(*erp))
5914                         goto finish;
5915
5916                 /* Both extents are fully inside boundaries. Swap it now */
5917                 tmp_ex = *ex1;
5918                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5919                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5920                 ex1->ee_len = cpu_to_le16(e2_len);
5921                 ex2->ee_len = cpu_to_le16(e1_len);
5922                 if (unwritten)
5923                         ext4_ext_mark_unwritten(ex2);
5924                 if (ext4_ext_is_unwritten(&tmp_ex))
5925                         ext4_ext_mark_unwritten(ex1);
5926
5927                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5928                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5929                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5930                                       path2->p_depth);
5931                 if (unlikely(*erp))
5932                         goto finish;
5933                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5934                                       path1->p_depth);
5935                 /*
5936                  * Looks scarry ah..? second inode already points to new blocks,
5937                  * and it was successfully dirtied. But luckily error may happen
5938                  * only due to journal error, so full transaction will be
5939                  * aborted anyway.
5940                  */
5941                 if (unlikely(*erp))
5942                         goto finish;
5943                 lblk1 += len;
5944                 lblk2 += len;
5945                 replaced_count += len;
5946                 count -= len;
5947
5948         repeat:
5949                 ext4_ext_drop_refs(path1);
5950                 kfree(path1);
5951                 ext4_ext_drop_refs(path2);
5952                 kfree(path2);
5953                 path1 = path2 = NULL;
5954         }
5955         return replaced_count;
5956 }