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 Licens
  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 "ext4_jbd2.h"
  43 #include "ext4_extents.h"
  44 #include "xattr.h"
  45
  46 #include <trace/events/ext4.h>
  47
  48 /*
  49  * used by extent splitting.
  50  */
  51 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  52                                         due to ENOSPC */
  53 #define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  54 #define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  55
  56 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  57 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  58
  59 static __le32 ext4_extent_block_csum(struct inode *inode,
  60                                      struct ext4_extent_header *eh)
  61 {
  62         struct ext4_inode_info *ei = EXT4_I(inode);
  63         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  64         __u32 csum;
  65
  66         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  67                            EXT4_EXTENT_TAIL_OFFSET(eh));
  68         return cpu_to_le32(csum);
  69 }
  70
  71 static int ext4_extent_block_csum_verify(struct inode *inode,
  72                                          struct ext4_extent_header *eh)
  73 {
  74         struct ext4_extent_tail *et;
  75
  76         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  77                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  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_RO_COMPAT_FEATURE(inode->i_sb,
  92                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  93                 return;
  94
  95         et = find_ext4_extent_tail(eh);
  96         et->et_checksum = ext4_extent_block_csum(inode, eh);
  97 }
  98
  99 static int ext4_split_extent(handle_t *handle,
 100                                 struct inode *inode,
 101                                 struct ext4_ext_path **ppath,
 102                                 struct ext4_map_blocks *map,
 103                                 int split_flag,
 104                                 int flags);
 105
 106 static int ext4_split_extent_at(handle_t *handle,
 107                              struct inode *inode,
 108                              struct ext4_ext_path **ppath,
 109                              ext4_lblk_t split,
 110                              int split_flag,
 111                              int flags);
 112
 113 static int ext4_find_delayed_extent(struct inode *inode,
 114                                     struct extent_status *newes);
 115
 116 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 117                                             struct inode *inode,
 118                                             int needed)
 119 {
 120         int err;
 121
 122         if (!ext4_handle_valid(handle))
 123                 return 0;
 124         if (handle->h_buffer_credits > needed)
 125                 return 0;
 126         err = ext4_journal_extend(handle, needed);
 127         if (err <= 0)
 128                 return err;
 129         err = ext4_truncate_restart_trans(handle, inode, needed);
 130         if (err == 0)
 131                 err = -EAGAIN;
 132
 133         return err;
 134 }
 135
 136 /*
 137  * could return:
 138  *  - EROFS
 139  *  - ENOMEM
 140  */
 141 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 142                                 struct ext4_ext_path *path)
 143 {
 144         if (path->p_bh) {
 145                 /* path points to block */
 146                 BUFFER_TRACE(path->p_bh, "get_write_access");
 147                 return ext4_journal_get_write_access(handle, path->p_bh);
 148         }
 149         /* path points to leaf/index in inode body */
 150         /* we use in-core data, no need to protect them */
 151         return 0;
 152 }
 153
 154 /*
 155  * could return:
 156  *  - EROFS
 157  *  - ENOMEM
 158  *  - EIO
 159  */
 160 int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 161                      struct inode *inode, struct ext4_ext_path *path)
 162 {
 163         int err;
 164
 165         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 166         if (path->p_bh) {
 167                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 168                 /* path points to block */
 169                 err = __ext4_handle_dirty_metadata(where, line, handle,
 170                                                    inode, path->p_bh);
 171         } else {
 172                 /* path points to leaf/index in inode body */
 173                 err = ext4_mark_inode_dirty(handle, inode);
 174         }
 175         return err;
 176 }
 177
 178 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 179                               struct ext4_ext_path *path,
 180                               ext4_lblk_t block)
 181 {
 182         if (path) {
 183                 int depth = path->p_depth;
 184                 struct ext4_extent *ex;
 185
 186                 /*
 187                  * Try to predict block placement assuming that we are
 188                  * filling in a file which will eventually be
 189                  * non-sparse --- i.e., in the case of libbfd writing
 190                  * an ELF object sections out-of-order but in a way
 191                  * the eventually results in a contiguous object or
 192                  * executable file, or some database extending a table
 193                  * space file.  However, this is actually somewhat
 194                  * non-ideal if we are writing a sparse file such as
 195                  * qemu or KVM writing a raw image file that is going
 196                  * to stay fairly sparse, since it will end up
 197                  * fragmenting the file system's free space.  Maybe we
 198                  * should have some hueristics or some way to allow
 199                  * userspace to pass a hint to file system,
 200                  * especially if the latter case turns out to be
 201                  * common.
 202                  */
 203                 ex = path[depth].p_ext;
 204                 if (ex) {
 205                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 206                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 207
 208                         if (block > ext_block)
 209                                 return ext_pblk + (block - ext_block);
 210                         else
 211                                 return ext_pblk - (ext_block - block);
 212                 }
 213
 214                 /* it looks like index is empty;
 215                  * try to find starting block from index itself */
 216                 if (path[depth].p_bh)
 217                         return path[depth].p_bh->b_blocknr;
 218         }
 219
 220         /* OK. use inode's group */
 221         return ext4_inode_to_goal_block(inode);
 222 }
 223
 224 /*
 225  * Allocation for a meta data block
 226  */
 227 static ext4_fsblk_t
 228 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 229                         struct ext4_ext_path *path,
 230                         struct ext4_extent *ex, int *err, unsigned int flags)
 231 {
 232         ext4_fsblk_t goal, newblock;
 233
 234         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 235         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 236                                         NULL, err);
 237         return newblock;
 238 }
 239
 240 static inline int ext4_ext_space_block(struct inode *inode, int check)
 241 {
 242         int size;
 243
 244         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 245                         / sizeof(struct ext4_extent);
 246 #ifdef AGGRESSIVE_TEST
 247         if (!check && size > 6)
 248                 size = 6;
 249 #endif
 250         return size;
 251 }
 252
 253 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 254 {
 255         int size;
 256
 257         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 258                         / sizeof(struct ext4_extent_idx);
 259 #ifdef AGGRESSIVE_TEST
 260         if (!check && size > 5)
 261                 size = 5;
 262 #endif
 263         return size;
 264 }
 265
 266 static inline int ext4_ext_space_root(struct inode *inode, int check)
 267 {
 268         int size;
 269
 270         size = sizeof(EXT4_I(inode)->i_data);
 271         size -= sizeof(struct ext4_extent_header);
 272         size /= sizeof(struct ext4_extent);
 273 #ifdef AGGRESSIVE_TEST
 274         if (!check && size > 3)
 275                 size = 3;
 276 #endif
 277         return size;
 278 }
 279
 280 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 281 {
 282         int size;
 283
 284         size = sizeof(EXT4_I(inode)->i_data);
 285         size -= sizeof(struct ext4_extent_header);
 286         size /= sizeof(struct ext4_extent_idx);
 287 #ifdef AGGRESSIVE_TEST
 288         if (!check && size > 4)
 289                 size = 4;
 290 #endif
 291         return size;
 292 }
 293
 294 static inline int
 295 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 296                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 297                            int nofail)
 298 {
 299         struct ext4_ext_path *path = *ppath;
 300         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 301
 302         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 303                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 304                         EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
 305                         (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
 306 }
 307
 308 /*
 309  * Calculate the number of metadata blocks needed
 310  * to allocate @blocks
 311  * Worse case is one block per extent
 312  */
 313 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 314 {
 315         struct ext4_inode_info *ei = EXT4_I(inode);
 316         int idxs;
 317
 318         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 319                 / sizeof(struct ext4_extent_idx));
 320
 321         /*
 322          * If the new delayed allocation block is contiguous with the
 323          * previous da block, it can share index blocks with the
 324          * previous block, so we only need to allocate a new index
 325          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 326          * an additional index block, and at ldxs**3 blocks, yet
 327          * another index blocks.
 328          */
 329         if (ei->i_da_metadata_calc_len &&
 330             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 331                 int num = 0;
 332
 333                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 334                         num++;
 335                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 336                         num++;
 337                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 338                         num++;
 339                         ei->i_da_metadata_calc_len = 0;
 340                 } else
 341                         ei->i_da_metadata_calc_len++;
 342                 ei->i_da_metadata_calc_last_lblock++;
 343                 return num;
 344         }
 345
 346         /*
 347          * In the worst case we need a new set of index blocks at
 348          * every level of the inode's extent tree.
 349          */
 350         ei->i_da_metadata_calc_len = 1;
 351         ei->i_da_metadata_calc_last_lblock = lblock;
 352         return ext_depth(inode) + 1;
 353 }
 354
 355 static int
 356 ext4_ext_max_entries(struct inode *inode, int depth)
 357 {
 358         int max;
 359
 360         if (depth == ext_depth(inode)) {
 361                 if (depth == 0)
 362                         max = ext4_ext_space_root(inode, 1);
 363                 else
 364                         max = ext4_ext_space_root_idx(inode, 1);
 365         } else {
 366                 if (depth == 0)
 367                         max = ext4_ext_space_block(inode, 1);
 368                 else
 369                         max = ext4_ext_space_block_idx(inode, 1);
 370         }
 371
 372         return max;
 373 }
 374
 375 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 376 {
 377         ext4_fsblk_t block = ext4_ext_pblock(ext);
 378         int len = ext4_ext_get_actual_len(ext);
 379         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 380         ext4_lblk_t last = lblock + len - 1;
 381
 382         if (lblock > last)
 383                 return 0;
 384         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 385 }
 386
 387 static int ext4_valid_extent_idx(struct inode *inode,
 388                                 struct ext4_extent_idx *ext_idx)
 389 {
 390         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 391
 392         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 393 }
 394
 395 static int ext4_valid_extent_entries(struct inode *inode,
 396                                 struct ext4_extent_header *eh,
 397                                 int depth)
 398 {
 399         unsigned short entries;
 400         if (eh->eh_entries == 0)
 401                 return 1;
 402
 403         entries = le16_to_cpu(eh->eh_entries);
 404
 405         if (depth == 0) {
 406                 /* leaf entries */
 407                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 408                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 409                 ext4_fsblk_t pblock = 0;
 410                 ext4_lblk_t lblock = 0;
 411                 ext4_lblk_t prev = 0;
 412                 int len = 0;
 413                 while (entries) {
 414                         if (!ext4_valid_extent(inode, ext))
 415                                 return 0;
 416
 417                         /* Check for overlapping extents */
 418                         lblock = le32_to_cpu(ext->ee_block);
 419                         len = ext4_ext_get_actual_len(ext);
 420                         if ((lblock <= prev) && prev) {
 421                                 pblock = ext4_ext_pblock(ext);
 422                                 es->s_last_error_block = cpu_to_le64(pblock);
 423                                 return 0;
 424                         }
 425                         ext++;
 426                         entries--;
 427                         prev = lblock + len - 1;
 428                 }
 429         } else {
 430                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 431                 while (entries) {
 432                         if (!ext4_valid_extent_idx(inode, ext_idx))
 433                                 return 0;
 434                         ext_idx++;
 435                         entries--;
 436                 }
 437         }
 438         return 1;
 439 }
 440
 441 static int __ext4_ext_check(const char *function, unsigned int line,
 442                             struct inode *inode, struct ext4_extent_header *eh,
 443                             int depth, ext4_fsblk_t pblk)
 444 {
 445         const char *error_msg;
 446         int max = 0;
 447
 448         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 449                 error_msg = "invalid magic";
 450                 goto corrupted;
 451         }
 452         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 453                 error_msg = "unexpected eh_depth";
 454                 goto corrupted;
 455         }
 456         if (unlikely(eh->eh_max == 0)) {
 457                 error_msg = "invalid eh_max";
 458                 goto corrupted;
 459         }
 460         max = ext4_ext_max_entries(inode, depth);
 461         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 462                 error_msg = "too large eh_max";
 463                 goto corrupted;
 464         }
 465         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 466                 error_msg = "invalid eh_entries";
 467                 goto corrupted;
 468         }
 469         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 470                 error_msg = "invalid extent entries";
 471                 goto corrupted;
 472         }
 473         /* Verify checksum on non-root extent tree nodes */
 474         if (ext_depth(inode) != depth &&
 475             !ext4_extent_block_csum_verify(inode, eh)) {
 476                 error_msg = "extent tree corrupted";
 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 -EIO;
 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(inode->i_sb, pblk);
 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 = path->p_depth;
 713         int i;
 714
 715         for (i = 0; i <= depth; i++, path++)
 716                 if (path->p_bh) {
 717                         brelse(path->p_bh);
 718                         path->p_bh = NULL;
 719                 }
 720 }
 721
 722 /*
 723  * ext4_ext_binsearch_idx:
 724  * binary search for the closest index of the given block
 725  * the header must be checked before calling this
 726  */
 727 static void
 728 ext4_ext_binsearch_idx(struct inode *inode,
 729                         struct ext4_ext_path *path, ext4_lblk_t block)
 730 {
 731         struct ext4_extent_header *eh = path->p_hdr;
 732         struct ext4_extent_idx *r, *l, *m;
 733
 734
 735         ext_debug("binsearch for %u(idx):  ", block);
 736
 737         l = EXT_FIRST_INDEX(eh) + 1;
 738         r = EXT_LAST_INDEX(eh);
 739         while (l <= r) {
 740                 m = l + (r - l) / 2;
 741                 if (block < le32_to_cpu(m->ei_block))
 742                         r = m - 1;
 743                 else
 744                         l = m + 1;
 745                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 746                                 m, le32_to_cpu(m->ei_block),
 747                                 r, le32_to_cpu(r->ei_block));
 748         }
 749
 750         path->p_idx = l - 1;
 751         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 752                   ext4_idx_pblock(path->p_idx));
 753
 754 #ifdef CHECK_BINSEARCH
 755         {
 756                 struct ext4_extent_idx *chix, *ix;
 757                 int k;
 758
 759                 chix = ix = EXT_FIRST_INDEX(eh);
 760                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 761                   if (k != 0 &&
 762                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 763                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 764                                        "first=0x%p\n", k,
 765                                        ix, EXT_FIRST_INDEX(eh));
 766                                 printk(KERN_DEBUG "%u <= %u\n",
 767                                        le32_to_cpu(ix->ei_block),
 768                                        le32_to_cpu(ix[-1].ei_block));
 769                         }
 770                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 771                                            <= le32_to_cpu(ix[-1].ei_block));
 772                         if (block < le32_to_cpu(ix->ei_block))
 773                                 break;
 774                         chix = ix;
 775                 }
 776                 BUG_ON(chix != path->p_idx);
 777         }
 778 #endif
 779
 780 }
 781
 782 /*
 783  * ext4_ext_binsearch:
 784  * binary search for closest extent of the given block
 785  * the header must be checked before calling this
 786  */
 787 static void
 788 ext4_ext_binsearch(struct inode *inode,
 789                 struct ext4_ext_path *path, ext4_lblk_t block)
 790 {
 791         struct ext4_extent_header *eh = path->p_hdr;
 792         struct ext4_extent *r, *l, *m;
 793
 794         if (eh->eh_entries == 0) {
 795                 /*
 796                  * this leaf is empty:
 797                  * we get such a leaf in split/add case
 798                  */
 799                 return;
 800         }
 801
 802         ext_debug("binsearch for %u:  ", block);
 803
 804         l = EXT_FIRST_EXTENT(eh) + 1;
 805         r = EXT_LAST_EXTENT(eh);
 806
 807         while (l <= r) {
 808                 m = l + (r - l) / 2;
 809                 if (block < le32_to_cpu(m->ee_block))
 810                         r = m - 1;
 811                 else
 812                         l = m + 1;
 813                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 814                                 m, le32_to_cpu(m->ee_block),
 815                                 r, le32_to_cpu(r->ee_block));
 816         }
 817
 818         path->p_ext = l - 1;
 819         ext_debug("  -> %d:%llu:[%d]%d ",
 820                         le32_to_cpu(path->p_ext->ee_block),
 821                         ext4_ext_pblock(path->p_ext),
 822                         ext4_ext_is_unwritten(path->p_ext),
 823                         ext4_ext_get_actual_len(path->p_ext));
 824
 825 #ifdef CHECK_BINSEARCH
 826         {
 827                 struct ext4_extent *chex, *ex;
 828                 int k;
 829
 830                 chex = ex = EXT_FIRST_EXTENT(eh);
 831                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 832                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 833                                           <= le32_to_cpu(ex[-1].ee_block));
 834                         if (block < le32_to_cpu(ex->ee_block))
 835                                 break;
 836                         chex = ex;
 837                 }
 838                 BUG_ON(chex != path->p_ext);
 839         }
 840 #endif
 841
 842 }
 843
 844 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 845 {
 846         struct ext4_extent_header *eh;
 847
 848         eh = ext_inode_hdr(inode);
 849         eh->eh_depth = 0;
 850         eh->eh_entries = 0;
 851         eh->eh_magic = EXT4_EXT_MAGIC;
 852         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 853         ext4_mark_inode_dirty(handle, inode);
 854         return 0;
 855 }
 856
 857 struct ext4_ext_path *
 858 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 859                      struct ext4_ext_path **orig_path, int flags)
 860 {
 861         struct ext4_extent_header *eh;
 862         struct buffer_head *bh;
 863         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 864         short int depth, i, ppos = 0;
 865         int ret;
 866
 867         eh = ext_inode_hdr(inode);
 868         depth = ext_depth(inode);
 869
 870         /* account possible depth increase */
 871         if (!path) {
 872                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 873                                 GFP_NOFS);
 874                 if (unlikely(!path))
 875                         return ERR_PTR(-ENOMEM);
 876         }
 877         path[0].p_hdr = eh;
 878         path[0].p_bh = NULL;
 879
 880         i = depth;
 881         /* walk through the tree */
 882         while (i) {
 883                 ext_debug("depth %d: num %d, max %d\n",
 884                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 885
 886                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 887                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 888                 path[ppos].p_depth = i;
 889                 path[ppos].p_ext = NULL;
 890
 891                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 892                                             flags);
 893                 if (unlikely(IS_ERR(bh))) {
 894                         ret = PTR_ERR(bh);
 895                         goto err;
 896                 }
 897
 898                 eh = ext_block_hdr(bh);
 899                 ppos++;
 900                 if (unlikely(ppos > depth)) {
 901                         put_bh(bh);
 902                         EXT4_ERROR_INODE(inode,
 903                                          "ppos %d > depth %d", ppos, depth);
 904                         ret = -EIO;
 905                         goto err;
 906                 }
 907                 path[ppos].p_bh = bh;
 908                 path[ppos].p_hdr = eh;
 909         }
 910
 911         path[ppos].p_depth = i;
 912         path[ppos].p_ext = NULL;
 913         path[ppos].p_idx = NULL;
 914
 915         /* find extent */
 916         ext4_ext_binsearch(inode, path + ppos, block);
 917         /* if not an empty leaf */
 918         if (path[ppos].p_ext)
 919                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 920
 921         ext4_ext_show_path(inode, path);
 922
 923         return path;
 924
 925 err:
 926         ext4_ext_drop_refs(path);
 927         kfree(path);
 928         if (orig_path)
 929                 *orig_path = NULL;
 930         return ERR_PTR(ret);
 931 }
 932
 933 /*
 934  * ext4_ext_insert_index:
 935  * insert new index [@logical;@ptr] into the block at @curp;
 936  * check where to insert: before @curp or after @curp
 937  */
 938 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 939                                  struct ext4_ext_path *curp,
 940                                  int logical, ext4_fsblk_t ptr)
 941 {
 942         struct ext4_extent_idx *ix;
 943         int len, err;
 944
 945         err = ext4_ext_get_access(handle, inode, curp);
 946         if (err)
 947                 return err;
 948
 949         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 950                 EXT4_ERROR_INODE(inode,
 951                                  "logical %d == ei_block %d!",
 952                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 953                 return -EIO;
 954         }
 955
 956         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 957                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 958                 EXT4_ERROR_INODE(inode,
 959                                  "eh_entries %d >= eh_max %d!",
 960                                  le16_to_cpu(curp->p_hdr->eh_entries),
 961                                  le16_to_cpu(curp->p_hdr->eh_max));
 962                 return -EIO;
 963         }
 964
 965         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 966                 /* insert after */
 967                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 968                 ix = curp->p_idx + 1;
 969         } else {
 970                 /* insert before */
 971                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 972                 ix = curp->p_idx;
 973         }
 974
 975         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 976         BUG_ON(len < 0);
 977         if (len > 0) {
 978                 ext_debug("insert new index %d: "
 979                                 "move %d indices from 0x%p to 0x%p\n",
 980                                 logical, len, ix, ix + 1);
 981                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 982         }
 983
 984         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 985                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 986                 return -EIO;
 987         }
 988
 989         ix->ei_block = cpu_to_le32(logical);
 990         ext4_idx_store_pblock(ix, ptr);
 991         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 992
 993         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 994                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 995                 return -EIO;
 996         }
 997
 998         err = ext4_ext_dirty(handle, inode, curp);
 999         ext4_std_error(inode->i_sb, err);
1000
1001         return err;
1002 }
1003
1004 /*
1005  * ext4_ext_split:
1006  * inserts new subtree into the path, using free index entry
1007  * at depth @at:
1008  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1009  * - makes decision where to split
1010  * - moves remaining extents and index entries (right to the split point)
1011  *   into the newly allocated blocks
1012  * - initializes subtree
1013  */
1014 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1015                           unsigned int flags,
1016                           struct ext4_ext_path *path,
1017                           struct ext4_extent *newext, int at)
1018 {
1019         struct buffer_head *bh = NULL;
1020         int depth = ext_depth(inode);
1021         struct ext4_extent_header *neh;
1022         struct ext4_extent_idx *fidx;
1023         int i = at, k, m, a;
1024         ext4_fsblk_t newblock, oldblock;
1025         __le32 border;
1026         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1027         int err = 0;
1028
1029         /* make decision: where to split? */
1030         /* FIXME: now decision is simplest: at current extent */
1031
1032         /* if current leaf will be split, then we should use
1033          * border from split point */
1034         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1035                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1036                 return -EIO;
1037         }
1038         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1039                 border = path[depth].p_ext[1].ee_block;
1040                 ext_debug("leaf will be split."
1041                                 " next leaf starts at %d\n",
1042                                   le32_to_cpu(border));
1043         } else {
1044                 border = newext->ee_block;
1045                 ext_debug("leaf will be added."
1046                                 " next leaf starts at %d\n",
1047                                 le32_to_cpu(border));
1048         }
1049
1050         /*
1051          * If error occurs, then we break processing
1052          * and mark filesystem read-only. index won't
1053          * be inserted and tree will be in consistent
1054          * state. Next mount will repair buffers too.
1055          */
1056
1057         /*
1058          * Get array to track all allocated blocks.
1059          * We need this to handle errors and free blocks
1060          * upon them.
1061          */
1062         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1063         if (!ablocks)
1064                 return -ENOMEM;
1065
1066         /* allocate all needed blocks */
1067         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1068         for (a = 0; a < depth - at; a++) {
1069                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1070                                                    newext, &err, flags);
1071                 if (newblock == 0)
1072                         goto cleanup;
1073                 ablocks[a] = newblock;
1074         }
1075
1076         /* initialize new leaf */
1077         newblock = ablocks[--a];
1078         if (unlikely(newblock == 0)) {
1079                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1080                 err = -EIO;
1081                 goto cleanup;
1082         }
1083         bh = sb_getblk(inode->i_sb, newblock);
1084         if (unlikely(!bh)) {
1085                 err = -ENOMEM;
1086                 goto cleanup;
1087         }
1088         lock_buffer(bh);
1089
1090         err = ext4_journal_get_create_access(handle, bh);
1091         if (err)
1092                 goto cleanup;
1093
1094         neh = ext_block_hdr(bh);
1095         neh->eh_entries = 0;
1096         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1097         neh->eh_magic = EXT4_EXT_MAGIC;
1098         neh->eh_depth = 0;
1099
1100         /* move remainder of path[depth] to the new leaf */
1101         if (unlikely(path[depth].p_hdr->eh_entries !=
1102                      path[depth].p_hdr->eh_max)) {
1103                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1104                                  path[depth].p_hdr->eh_entries,
1105                                  path[depth].p_hdr->eh_max);
1106                 err = -EIO;
1107                 goto cleanup;
1108         }
1109         /* start copy from next extent */
1110         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1111         ext4_ext_show_move(inode, path, newblock, depth);
1112         if (m) {
1113                 struct ext4_extent *ex;
1114                 ex = EXT_FIRST_EXTENT(neh);
1115                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1116                 le16_add_cpu(&neh->eh_entries, m);
1117         }
1118
1119         ext4_extent_block_csum_set(inode, neh);
1120         set_buffer_uptodate(bh);
1121         unlock_buffer(bh);
1122
1123         err = ext4_handle_dirty_metadata(handle, inode, bh);
1124         if (err)
1125                 goto cleanup;
1126         brelse(bh);
1127         bh = NULL;
1128
1129         /* correct old leaf */
1130         if (m) {
1131                 err = ext4_ext_get_access(handle, inode, path + depth);
1132                 if (err)
1133                         goto cleanup;
1134                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1135                 err = ext4_ext_dirty(handle, inode, path + depth);
1136                 if (err)
1137                         goto cleanup;
1138
1139         }
1140
1141         /* create intermediate indexes */
1142         k = depth - at - 1;
1143         if (unlikely(k < 0)) {
1144                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1145                 err = -EIO;
1146                 goto cleanup;
1147         }
1148         if (k)
1149                 ext_debug("create %d intermediate indices\n", k);
1150         /* insert new index into current index block */
1151         /* current depth stored in i var */
1152         i = depth - 1;
1153         while (k--) {
1154                 oldblock = newblock;
1155                 newblock = ablocks[--a];
1156                 bh = sb_getblk(inode->i_sb, newblock);
1157                 if (unlikely(!bh)) {
1158                         err = -ENOMEM;
1159                         goto cleanup;
1160                 }
1161                 lock_buffer(bh);
1162
1163                 err = ext4_journal_get_create_access(handle, bh);
1164                 if (err)
1165                         goto cleanup;
1166
1167                 neh = ext_block_hdr(bh);
1168                 neh->eh_entries = cpu_to_le16(1);
1169                 neh->eh_magic = EXT4_EXT_MAGIC;
1170                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1171                 neh->eh_depth = cpu_to_le16(depth - i);
1172                 fidx = EXT_FIRST_INDEX(neh);
1173                 fidx->ei_block = border;
1174                 ext4_idx_store_pblock(fidx, oldblock);
1175
1176                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1177                                 i, newblock, le32_to_cpu(border), oldblock);
1178
1179                 /* move remainder of path[i] to the new index block */
1180                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1181                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1182                         EXT4_ERROR_INODE(inode,
1183                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1184                                          le32_to_cpu(path[i].p_ext->ee_block));
1185                         err = -EIO;
1186                         goto cleanup;
1187                 }
1188                 /* start copy indexes */
1189                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1190                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1191                                 EXT_MAX_INDEX(path[i].p_hdr));
1192                 ext4_ext_show_move(inode, path, newblock, i);
1193                 if (m) {
1194                         memmove(++fidx, path[i].p_idx,
1195                                 sizeof(struct ext4_extent_idx) * m);
1196                         le16_add_cpu(&neh->eh_entries, m);
1197                 }
1198                 ext4_extent_block_csum_set(inode, neh);
1199                 set_buffer_uptodate(bh);
1200                 unlock_buffer(bh);
1201
1202                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1203                 if (err)
1204                         goto cleanup;
1205                 brelse(bh);
1206                 bh = NULL;
1207
1208                 /* correct old index */
1209                 if (m) {
1210                         err = ext4_ext_get_access(handle, inode, path + i);
1211                         if (err)
1212                                 goto cleanup;
1213                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1214                         err = ext4_ext_dirty(handle, inode, path + i);
1215                         if (err)
1216                                 goto cleanup;
1217                 }
1218
1219                 i--;
1220         }
1221
1222         /* insert new index */
1223         err = ext4_ext_insert_index(handle, inode, path + at,
1224                                     le32_to_cpu(border), newblock);
1225
1226 cleanup:
1227         if (bh) {
1228                 if (buffer_locked(bh))
1229                         unlock_buffer(bh);
1230                 brelse(bh);
1231         }
1232
1233         if (err) {
1234                 /* free all allocated blocks in error case */
1235                 for (i = 0; i < depth; i++) {
1236                         if (!ablocks[i])
1237                                 continue;
1238                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1239                                          EXT4_FREE_BLOCKS_METADATA);
1240                 }
1241         }
1242         kfree(ablocks);
1243
1244         return err;
1245 }
1246
1247 /*
1248  * ext4_ext_grow_indepth:
1249  * implements tree growing procedure:
1250  * - allocates new block
1251  * - moves top-level data (index block or leaf) into the new block
1252  * - initializes new top-level, creating index that points to the
1253  *   just created block
1254  */
1255 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1256                                  unsigned int flags,
1257                                  struct ext4_extent *newext)
1258 {
1259         struct ext4_extent_header *neh;
1260         struct buffer_head *bh;
1261         ext4_fsblk_t newblock;
1262         int err = 0;
1263
1264         newblock = ext4_ext_new_meta_block(handle, inode, NULL,
1265                 newext, &err, flags);
1266         if (newblock == 0)
1267                 return err;
1268
1269         bh = sb_getblk(inode->i_sb, newblock);
1270         if (unlikely(!bh))
1271                 return -ENOMEM;
1272         lock_buffer(bh);
1273
1274         err = ext4_journal_get_create_access(handle, bh);
1275         if (err) {
1276                 unlock_buffer(bh);
1277                 goto out;
1278         }
1279
1280         /* move top-level index/leaf into new block */
1281         memmove(bh->b_data, EXT4_I(inode)->i_data,
1282                 sizeof(EXT4_I(inode)->i_data));
1283
1284         /* set size of new block */
1285         neh = ext_block_hdr(bh);
1286         /* old root could have indexes or leaves
1287          * so calculate e_max right way */
1288         if (ext_depth(inode))
1289                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1290         else
1291                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1292         neh->eh_magic = EXT4_EXT_MAGIC;
1293         ext4_extent_block_csum_set(inode, neh);
1294         set_buffer_uptodate(bh);
1295         unlock_buffer(bh);
1296
1297         err = ext4_handle_dirty_metadata(handle, inode, bh);
1298         if (err)
1299                 goto out;
1300
1301         /* Update top-level index: num,max,pointer */
1302         neh = ext_inode_hdr(inode);
1303         neh->eh_entries = cpu_to_le16(1);
1304         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1305         if (neh->eh_depth == 0) {
1306                 /* Root extent block becomes index block */
1307                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1308                 EXT_FIRST_INDEX(neh)->ei_block =
1309                         EXT_FIRST_EXTENT(neh)->ee_block;
1310         }
1311         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1312                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1313                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1314                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1315
1316         le16_add_cpu(&neh->eh_depth, 1);
1317         ext4_mark_inode_dirty(handle, inode);
1318 out:
1319         brelse(bh);
1320
1321         return err;
1322 }
1323
1324 /*
1325  * ext4_ext_create_new_leaf:
1326  * finds empty index and adds new leaf.
1327  * if no free index is found, then it requests in-depth growing.
1328  */
1329 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1330                                     unsigned int mb_flags,
1331                                     unsigned int gb_flags,
1332                                     struct ext4_ext_path **ppath,
1333                                     struct ext4_extent *newext)
1334 {
1335         struct ext4_ext_path *path = *ppath;
1336         struct ext4_ext_path *curp;
1337         int depth, i, err = 0;
1338
1339 repeat:
1340         i = depth = ext_depth(inode);
1341
1342         /* walk up to the tree and look for free index entry */
1343         curp = path + depth;
1344         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1345                 i--;
1346                 curp--;
1347         }
1348
1349         /* we use already allocated block for index block,
1350          * so subsequent data blocks should be contiguous */
1351         if (EXT_HAS_FREE_INDEX(curp)) {
1352                 /* if we found index with free entry, then use that
1353                  * entry: create all needed subtree and add new leaf */
1354                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1355                 if (err)
1356                         goto out;
1357
1358                 /* refill path */
1359                 ext4_ext_drop_refs(path);
1360                 path = ext4_ext_find_extent(inode,
1361                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1362                                     ppath, gb_flags);
1363                 if (IS_ERR(path))
1364                         err = PTR_ERR(path);
1365         } else {
1366                 /* tree is full, time to grow in depth */
1367                 err = ext4_ext_grow_indepth(handle, inode, mb_flags, newext);
1368                 if (err)
1369                         goto out;
1370
1371                 /* refill path */
1372                 ext4_ext_drop_refs(path);
1373                 path = ext4_ext_find_extent(inode,
1374                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1375                                     ppath, gb_flags);
1376                 if (IS_ERR(path)) {
1377                         err = PTR_ERR(path);
1378                         goto out;
1379                 }
1380
1381                 /*
1382                  * only first (depth 0 -> 1) produces free space;
1383                  * in all other cases we have to split the grown tree
1384                  */
1385                 depth = ext_depth(inode);
1386                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1387                         /* now we need to split */
1388                         goto repeat;
1389                 }
1390         }
1391
1392 out:
1393         return err;
1394 }
1395
1396 /*
1397  * search the closest allocated block to the left for *logical
1398  * and returns it at @logical + it's physical address at @phys
1399  * if *logical is the smallest allocated block, the function
1400  * returns 0 at @phys
1401  * return value contains 0 (success) or error code
1402  */
1403 static int ext4_ext_search_left(struct inode *inode,
1404                                 struct ext4_ext_path *path,
1405                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1406 {
1407         struct ext4_extent_idx *ix;
1408         struct ext4_extent *ex;
1409         int depth, ee_len;
1410
1411         if (unlikely(path == NULL)) {
1412                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1413                 return -EIO;
1414         }
1415         depth = path->p_depth;
1416         *phys = 0;
1417
1418         if (depth == 0 && path->p_ext == NULL)
1419                 return 0;
1420
1421         /* usually extent in the path covers blocks smaller
1422          * then *logical, but it can be that extent is the
1423          * first one in the file */
1424
1425         ex = path[depth].p_ext;
1426         ee_len = ext4_ext_get_actual_len(ex);
1427         if (*logical < le32_to_cpu(ex->ee_block)) {
1428                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1429                         EXT4_ERROR_INODE(inode,
1430                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1431                                          *logical, le32_to_cpu(ex->ee_block));
1432                         return -EIO;
1433                 }
1434                 while (--depth >= 0) {
1435                         ix = path[depth].p_idx;
1436                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1437                                 EXT4_ERROR_INODE(inode,
1438                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1439                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1440                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1441                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1442                                   depth);
1443                                 return -EIO;
1444                         }
1445                 }
1446                 return 0;
1447         }
1448
1449         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1450                 EXT4_ERROR_INODE(inode,
1451                                  "logical %d < ee_block %d + ee_len %d!",
1452                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1453                 return -EIO;
1454         }
1455
1456         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1457         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1458         return 0;
1459 }
1460
1461 /*
1462  * search the closest allocated block to the right for *logical
1463  * and returns it at @logical + it's physical address at @phys
1464  * if *logical is the largest allocated block, the function
1465  * returns 0 at @phys
1466  * return value contains 0 (success) or error code
1467  */
1468 static int ext4_ext_search_right(struct inode *inode,
1469                                  struct ext4_ext_path *path,
1470                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1471                                  struct ext4_extent **ret_ex)
1472 {
1473         struct buffer_head *bh = NULL;
1474         struct ext4_extent_header *eh;
1475         struct ext4_extent_idx *ix;
1476         struct ext4_extent *ex;
1477         ext4_fsblk_t block;
1478         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1479         int ee_len;
1480
1481         if (unlikely(path == NULL)) {
1482                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1483                 return -EIO;
1484         }
1485         depth = path->p_depth;
1486         *phys = 0;
1487
1488         if (depth == 0 && path->p_ext == NULL)
1489                 return 0;
1490
1491         /* usually extent in the path covers blocks smaller
1492          * then *logical, but it can be that extent is the
1493          * first one in the file */
1494
1495         ex = path[depth].p_ext;
1496         ee_len = ext4_ext_get_actual_len(ex);
1497         if (*logical < le32_to_cpu(ex->ee_block)) {
1498                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1499                         EXT4_ERROR_INODE(inode,
1500                                          "first_extent(path[%d].p_hdr) != ex",
1501                                          depth);
1502                         return -EIO;
1503                 }
1504                 while (--depth >= 0) {
1505                         ix = path[depth].p_idx;
1506                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1507                                 EXT4_ERROR_INODE(inode,
1508                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1509                                                  *logical);
1510                                 return -EIO;
1511                         }
1512                 }
1513                 goto found_extent;
1514         }
1515
1516         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1517                 EXT4_ERROR_INODE(inode,
1518                                  "logical %d < ee_block %d + ee_len %d!",
1519                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1520                 return -EIO;
1521         }
1522
1523         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1524                 /* next allocated block in this leaf */
1525                 ex++;
1526                 goto found_extent;
1527         }
1528
1529         /* go up and search for index to the right */
1530         while (--depth >= 0) {
1531                 ix = path[depth].p_idx;
1532                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1533                         goto got_index;
1534         }
1535
1536         /* we've gone up to the root and found no index to the right */
1537         return 0;
1538
1539 got_index:
1540         /* we've found index to the right, let's
1541          * follow it and find the closest allocated
1542          * block to the right */
1543         ix++;
1544         block = ext4_idx_pblock(ix);
1545         while (++depth < path->p_depth) {
1546                 /* subtract from p_depth to get proper eh_depth */
1547                 bh = read_extent_tree_block(inode, block,
1548                                             path->p_depth - depth, 0);
1549                 if (IS_ERR(bh))
1550                         return PTR_ERR(bh);
1551                 eh = ext_block_hdr(bh);
1552                 ix = EXT_FIRST_INDEX(eh);
1553                 block = ext4_idx_pblock(ix);
1554                 put_bh(bh);
1555         }
1556
1557         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1558         if (IS_ERR(bh))
1559                 return PTR_ERR(bh);
1560         eh = ext_block_hdr(bh);
1561         ex = EXT_FIRST_EXTENT(eh);
1562 found_extent:
1563         *logical = le32_to_cpu(ex->ee_block);
1564         *phys = ext4_ext_pblock(ex);
1565         *ret_ex = ex;
1566         if (bh)
1567                 put_bh(bh);
1568         return 0;
1569 }
1570
1571 /*
1572  * ext4_ext_next_allocated_block:
1573  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1574  * NOTE: it considers block number from index entry as
1575  * allocated block. Thus, index entries have to be consistent
1576  * with leaves.
1577  */
1578 ext4_lblk_t
1579 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1580 {
1581         int depth;
1582
1583         BUG_ON(path == NULL);
1584         depth = path->p_depth;
1585
1586         if (depth == 0 && path->p_ext == NULL)
1587                 return EXT_MAX_BLOCKS;
1588
1589         while (depth >= 0) {
1590                 if (depth == path->p_depth) {
1591                         /* leaf */
1592                         if (path[depth].p_ext &&
1593                                 path[depth].p_ext !=
1594                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1595                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1596                 } else {
1597                         /* index */
1598                         if (path[depth].p_idx !=
1599                                         EXT_LAST_INDEX(path[depth].p_hdr))
1600                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1601                 }
1602                 depth--;
1603         }
1604
1605         return EXT_MAX_BLOCKS;
1606 }
1607
1608 /*
1609  * ext4_ext_next_leaf_block:
1610  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1611  */
1612 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1613 {
1614         int depth;
1615
1616         BUG_ON(path == NULL);
1617         depth = path->p_depth;
1618
1619         /* zero-tree has no leaf blocks at all */
1620         if (depth == 0)
1621                 return EXT_MAX_BLOCKS;
1622
1623         /* go to index block */
1624         depth--;
1625
1626         while (depth >= 0) {
1627                 if (path[depth].p_idx !=
1628                                 EXT_LAST_INDEX(path[depth].p_hdr))
1629                         return (ext4_lblk_t)
1630                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1631                 depth--;
1632         }
1633
1634         return EXT_MAX_BLOCKS;
1635 }
1636
1637 /*
1638  * ext4_ext_correct_indexes:
1639  * if leaf gets modified and modified extent is first in the leaf,
1640  * then we have to correct all indexes above.
1641  * TODO: do we need to correct tree in all cases?
1642  */
1643 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1644                                 struct ext4_ext_path *path)
1645 {
1646         struct ext4_extent_header *eh;
1647         int depth = ext_depth(inode);
1648         struct ext4_extent *ex;
1649         __le32 border;
1650         int k, err = 0;
1651
1652         eh = path[depth].p_hdr;
1653         ex = path[depth].p_ext;
1654
1655         if (unlikely(ex == NULL || eh == NULL)) {
1656                 EXT4_ERROR_INODE(inode,
1657                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1658                 return -EIO;
1659         }
1660
1661         if (depth == 0) {
1662                 /* there is no tree at all */
1663                 return 0;
1664         }
1665
1666         if (ex != EXT_FIRST_EXTENT(eh)) {
1667                 /* we correct tree if first leaf got modified only */
1668                 return 0;
1669         }
1670
1671         /*
1672          * TODO: we need correction if border is smaller than current one
1673          */
1674         k = depth - 1;
1675         border = path[depth].p_ext->ee_block;
1676         err = ext4_ext_get_access(handle, inode, path + k);
1677         if (err)
1678                 return err;
1679         path[k].p_idx->ei_block = border;
1680         err = ext4_ext_dirty(handle, inode, path + k);
1681         if (err)
1682                 return err;
1683
1684         while (k--) {
1685                 /* change all left-side indexes */
1686                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1687                         break;
1688                 err = ext4_ext_get_access(handle, inode, path + k);
1689                 if (err)
1690                         break;
1691                 path[k].p_idx->ei_block = border;
1692                 err = ext4_ext_dirty(handle, inode, path + k);
1693                 if (err)
1694                         break;
1695         }
1696
1697         return err;
1698 }
1699
1700 int
1701 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1702                                 struct ext4_extent *ex2)
1703 {
1704         unsigned short ext1_ee_len, ext2_ee_len;
1705
1706         /*
1707          * Make sure that both extents are initialized. We don't merge
1708          * unwritten extents so that we can be sure that end_io code has
1709          * the extent that was written properly split out and conversion to
1710          * initialized is trivial.
1711          */
1712         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1713                 return 0;
1714
1715         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1716         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1717
1718         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1719                         le32_to_cpu(ex2->ee_block))
1720                 return 0;
1721
1722         /*
1723          * To allow future support for preallocated extents to be added
1724          * as an RO_COMPAT feature, refuse to merge to extents if
1725          * this can result in the top bit of ee_len being set.
1726          */
1727         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1728                 return 0;
1729         if (ext4_ext_is_unwritten(ex1) &&
1730             (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1731              atomic_read(&EXT4_I(inode)->i_unwritten) ||
1732              (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1733                 return 0;
1734 #ifdef AGGRESSIVE_TEST
1735         if (ext1_ee_len >= 4)
1736                 return 0;
1737 #endif
1738
1739         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1740                 return 1;
1741         return 0;
1742 }
1743
1744 /*
1745  * This function tries to merge the "ex" extent to the next extent in the tree.
1746  * It always tries to merge towards right. If you want to merge towards
1747  * left, pass "ex - 1" as argument instead of "ex".
1748  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1749  * 1 if they got merged.
1750  */
1751 static int ext4_ext_try_to_merge_right(struct inode *inode,
1752                                  struct ext4_ext_path *path,
1753                                  struct ext4_extent *ex)
1754 {
1755         struct ext4_extent_header *eh;
1756         unsigned int depth, len;
1757         int merge_done = 0, unwritten;
1758
1759         depth = ext_depth(inode);
1760         BUG_ON(path[depth].p_hdr == NULL);
1761         eh = path[depth].p_hdr;
1762
1763         while (ex < EXT_LAST_EXTENT(eh)) {
1764                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1765                         break;
1766                 /* merge with next extent! */
1767                 unwritten = ext4_ext_is_unwritten(ex);
1768                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1769                                 + ext4_ext_get_actual_len(ex + 1));
1770                 if (unwritten)
1771                         ext4_ext_mark_unwritten(ex);
1772
1773                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1774                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1775                                 * sizeof(struct ext4_extent);
1776                         memmove(ex + 1, ex + 2, len);
1777                 }
1778                 le16_add_cpu(&eh->eh_entries, -1);
1779                 merge_done = 1;
1780                 WARN_ON(eh->eh_entries == 0);
1781                 if (!eh->eh_entries)
1782                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1783         }
1784
1785         return merge_done;
1786 }
1787
1788 /*
1789  * This function does a very simple check to see if we can collapse
1790  * an extent tree with a single extent tree leaf block into the inode.
1791  */
1792 static void ext4_ext_try_to_merge_up(handle_t *handle,
1793                                      struct inode *inode,
1794                                      struct ext4_ext_path *path)
1795 {
1796         size_t s;
1797         unsigned max_root = ext4_ext_space_root(inode, 0);
1798         ext4_fsblk_t blk;
1799
1800         if ((path[0].p_depth != 1) ||
1801             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1802             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1803                 return;
1804
1805         /*
1806          * We need to modify the block allocation bitmap and the block
1807          * group descriptor to release the extent tree block.  If we
1808          * can't get the journal credits, give up.
1809          */
1810         if (ext4_journal_extend(handle, 2))
1811                 return;
1812
1813         /*
1814          * Copy the extent data up to the inode
1815          */
1816         blk = ext4_idx_pblock(path[0].p_idx);
1817         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1818                 sizeof(struct ext4_extent_idx);
1819         s += sizeof(struct ext4_extent_header);
1820
1821         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1822         path[0].p_depth = 0;
1823         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1824                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1825         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1826
1827         brelse(path[1].p_bh);
1828         ext4_free_blocks(handle, inode, NULL, blk, 1,
1829                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1830 }
1831
1832 /*
1833  * This function tries to merge the @ex extent to neighbours in the tree.
1834  * return 1 if merge left else 0.
1835  */
1836 static void ext4_ext_try_to_merge(handle_t *handle,
1837                                   struct inode *inode,
1838                                   struct ext4_ext_path *path,
1839                                   struct ext4_extent *ex) {
1840         struct ext4_extent_header *eh;
1841         unsigned int depth;
1842         int merge_done = 0;
1843
1844         depth = ext_depth(inode);
1845         BUG_ON(path[depth].p_hdr == NULL);
1846         eh = path[depth].p_hdr;
1847
1848         if (ex > EXT_FIRST_EXTENT(eh))
1849                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1850
1851         if (!merge_done)
1852                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1853
1854         ext4_ext_try_to_merge_up(handle, inode, path);
1855 }
1856
1857 /*
1858  * check if a portion of the "newext" extent overlaps with an
1859  * existing extent.
1860  *
1861  * If there is an overlap discovered, it updates the length of the newext
1862  * such that there will be no overlap, and then returns 1.
1863  * If there is no overlap found, it returns 0.
1864  */
1865 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1866                                            struct inode *inode,
1867                                            struct ext4_extent *newext,
1868                                            struct ext4_ext_path *path)
1869 {
1870         ext4_lblk_t b1, b2;
1871         unsigned int depth, len1;
1872         unsigned int ret = 0;
1873
1874         b1 = le32_to_cpu(newext->ee_block);
1875         len1 = ext4_ext_get_actual_len(newext);
1876         depth = ext_depth(inode);
1877         if (!path[depth].p_ext)
1878                 goto out;
1879         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1880
1881         /*
1882          * get the next allocated block if the extent in the path
1883          * is before the requested block(s)
1884          */
1885         if (b2 < b1) {
1886                 b2 = ext4_ext_next_allocated_block(path);
1887                 if (b2 == EXT_MAX_BLOCKS)
1888                         goto out;
1889                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1890         }
1891
1892         /* check for wrap through zero on extent logical start block*/
1893         if (b1 + len1 < b1) {
1894                 len1 = EXT_MAX_BLOCKS - b1;
1895                 newext->ee_len = cpu_to_le16(len1);
1896                 ret = 1;
1897         }
1898
1899         /* check for overlap */
1900         if (b1 + len1 > b2) {
1901                 newext->ee_len = cpu_to_le16(b2 - b1);
1902                 ret = 1;
1903         }
1904 out:
1905         return ret;
1906 }
1907
1908 /*
1909  * ext4_ext_insert_extent:
1910  * tries to merge requsted extent into the existing extent or
1911  * inserts requested extent as new one into the tree,
1912  * creating new leaf in the no-space case.
1913  */
1914 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1915                                 struct ext4_ext_path **ppath,
1916                                 struct ext4_extent *newext, int gb_flags)
1917 {
1918         struct ext4_ext_path *path = *ppath;
1919         struct ext4_extent_header *eh;
1920         struct ext4_extent *ex, *fex;
1921         struct ext4_extent *nearex; /* nearest extent */
1922         struct ext4_ext_path *npath = NULL;
1923         int depth, len, err;
1924         ext4_lblk_t next;
1925         int mb_flags = 0, unwritten;
1926
1927         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1928                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1929                 return -EIO;
1930         }
1931         depth = ext_depth(inode);
1932         ex = path[depth].p_ext;
1933         eh = path[depth].p_hdr;
1934         if (unlikely(path[depth].p_hdr == NULL)) {
1935                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1936                 return -EIO;
1937         }
1938
1939         /* try to insert block into found extent and return */
1940         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1941
1942                 /*
1943                  * Try to see whether we should rather test the extent on
1944                  * right from ex, or from the left of ex. This is because
1945                  * ext4_ext_find_extent() can return either extent on the
1946                  * left, or on the right from the searched position. This
1947                  * will make merging more effective.
1948                  */
1949                 if (ex < EXT_LAST_EXTENT(eh) &&
1950                     (le32_to_cpu(ex->ee_block) +
1951                     ext4_ext_get_actual_len(ex) <
1952                     le32_to_cpu(newext->ee_block))) {
1953                         ex += 1;
1954                         goto prepend;
1955                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1956                            (le32_to_cpu(newext->ee_block) +
1957                            ext4_ext_get_actual_len(newext) <
1958                            le32_to_cpu(ex->ee_block)))
1959                         ex -= 1;
1960
1961                 /* Try to append newex to the ex */
1962                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1963                         ext_debug("append [%d]%d block to %u:[%d]%d"
1964                                   "(from %llu)\n",
1965                                   ext4_ext_is_unwritten(newext),
1966                                   ext4_ext_get_actual_len(newext),
1967                                   le32_to_cpu(ex->ee_block),
1968                                   ext4_ext_is_unwritten(ex),
1969                                   ext4_ext_get_actual_len(ex),
1970                                   ext4_ext_pblock(ex));
1971                         err = ext4_ext_get_access(handle, inode,
1972                                                   path + depth);
1973                         if (err)
1974                                 return err;
1975                         unwritten = ext4_ext_is_unwritten(ex);
1976                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1977                                         + ext4_ext_get_actual_len(newext));
1978                         if (unwritten)
1979                                 ext4_ext_mark_unwritten(ex);
1980                         eh = path[depth].p_hdr;
1981                         nearex = ex;
1982                         goto merge;
1983                 }
1984
1985 prepend:
1986                 /* Try to prepend newex to the ex */
1987                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
1988                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
1989                                   "(from %llu)\n",
1990                                   le32_to_cpu(newext->ee_block),
1991                                   ext4_ext_is_unwritten(newext),
1992                                   ext4_ext_get_actual_len(newext),
1993                                   le32_to_cpu(ex->ee_block),
1994                                   ext4_ext_is_unwritten(ex),
1995                                   ext4_ext_get_actual_len(ex),
1996                                   ext4_ext_pblock(ex));
1997                         err = ext4_ext_get_access(handle, inode,
1998                                                   path + depth);
1999                         if (err)
2000                                 return err;
2001
2002                         unwritten = ext4_ext_is_unwritten(ex);
2003                         ex->ee_block = newext->ee_block;
2004                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2005                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2006                                         + ext4_ext_get_actual_len(newext));
2007                         if (unwritten)
2008                                 ext4_ext_mark_unwritten(ex);
2009                         eh = path[depth].p_hdr;
2010                         nearex = ex;
2011                         goto merge;
2012                 }
2013         }
2014
2015         depth = ext_depth(inode);
2016         eh = path[depth].p_hdr;
2017         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2018                 goto has_space;
2019
2020         /* probably next leaf has space for us? */
2021         fex = EXT_LAST_EXTENT(eh);
2022         next = EXT_MAX_BLOCKS;
2023         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2024                 next = ext4_ext_next_leaf_block(path);
2025         if (next != EXT_MAX_BLOCKS) {
2026                 ext_debug("next leaf block - %u\n", next);
2027                 BUG_ON(npath != NULL);
2028                 npath = ext4_ext_find_extent(inode, next, NULL, 0);
2029                 if (IS_ERR(npath))
2030                         return PTR_ERR(npath);
2031                 BUG_ON(npath->p_depth != path->p_depth);
2032                 eh = npath[depth].p_hdr;
2033                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2034                         ext_debug("next leaf isn't full(%d)\n",
2035                                   le16_to_cpu(eh->eh_entries));
2036                         path = npath;
2037                         goto has_space;
2038                 }
2039                 ext_debug("next leaf has no free space(%d,%d)\n",
2040                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2041         }
2042
2043         /*
2044          * There is no free space in the found leaf.
2045          * We're gonna add a new leaf in the tree.
2046          */
2047         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2048                 mb_flags = EXT4_MB_USE_RESERVED;
2049         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2050                                        ppath, newext);
2051         if (err)
2052                 goto cleanup;
2053         depth = ext_depth(inode);
2054         eh = path[depth].p_hdr;
2055
2056 has_space:
2057         nearex = path[depth].p_ext;
2058
2059         err = ext4_ext_get_access(handle, inode, path + depth);
2060         if (err)
2061                 goto cleanup;
2062
2063         if (!nearex) {
2064                 /* there is no extent in this leaf, create first one */
2065                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2066                                 le32_to_cpu(newext->ee_block),
2067                                 ext4_ext_pblock(newext),
2068                                 ext4_ext_is_unwritten(newext),
2069                                 ext4_ext_get_actual_len(newext));
2070                 nearex = EXT_FIRST_EXTENT(eh);
2071         } else {
2072                 if (le32_to_cpu(newext->ee_block)
2073                            > le32_to_cpu(nearex->ee_block)) {
2074                         /* Insert after */
2075                         ext_debug("insert %u:%llu:[%d]%d before: "
2076                                         "nearest %p\n",
2077                                         le32_to_cpu(newext->ee_block),
2078                                         ext4_ext_pblock(newext),
2079                                         ext4_ext_is_unwritten(newext),
2080                                         ext4_ext_get_actual_len(newext),
2081                                         nearex);
2082                         nearex++;
2083                 } else {
2084                         /* Insert before */
2085                         BUG_ON(newext->ee_block == nearex->ee_block);
2086                         ext_debug("insert %u:%llu:[%d]%d after: "
2087                                         "nearest %p\n",
2088                                         le32_to_cpu(newext->ee_block),
2089                                         ext4_ext_pblock(newext),
2090                                         ext4_ext_is_unwritten(newext),
2091                                         ext4_ext_get_actual_len(newext),
2092                                         nearex);
2093                 }
2094                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2095                 if (len > 0) {
2096                         ext_debug("insert %u:%llu:[%d]%d: "
2097                                         "move %d extents from 0x%p to 0x%p\n",
2098                                         le32_to_cpu(newext->ee_block),
2099                                         ext4_ext_pblock(newext),
2100                                         ext4_ext_is_unwritten(newext),
2101                                         ext4_ext_get_actual_len(newext),
2102                                         len, nearex, nearex + 1);
2103                         memmove(nearex + 1, nearex,
2104                                 len * sizeof(struct ext4_extent));
2105                 }
2106         }
2107
2108         le16_add_cpu(&eh->eh_entries, 1);
2109         path[depth].p_ext = nearex;
2110         nearex->ee_block = newext->ee_block;
2111         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2112         nearex->ee_len = newext->ee_len;
2113
2114 merge:
2115         /* try to merge extents */
2116         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2117                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2118
2119
2120         /* time to correct all indexes above */
2121         err = ext4_ext_correct_indexes(handle, inode, path);
2122         if (err)
2123                 goto cleanup;
2124
2125         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2126
2127 cleanup:
2128         if (npath) {
2129                 ext4_ext_drop_refs(npath);
2130                 kfree(npath);
2131         }
2132         return err;
2133 }
2134
2135 static int ext4_fill_fiemap_extents(struct inode *inode,
2136                                     ext4_lblk_t block, ext4_lblk_t num,
2137                                     struct fiemap_extent_info *fieinfo)
2138 {
2139         struct ext4_ext_path *path = NULL;
2140         struct ext4_extent *ex;
2141         struct extent_status es;
2142         ext4_lblk_t next, next_del, start = 0, end = 0;
2143         ext4_lblk_t last = block + num;
2144         int exists, depth = 0, err = 0;
2145         unsigned int flags = 0;
2146         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2147
2148         while (block < last && block != EXT_MAX_BLOCKS) {
2149                 num = last - block;
2150                 /* find extent for this block */
2151                 down_read(&EXT4_I(inode)->i_data_sem);
2152
2153                 if (path && ext_depth(inode) != depth) {
2154                         /* depth was changed. we have to realloc path */
2155                         kfree(path);
2156                         path = NULL;
2157                 }
2158
2159                 path = ext4_ext_find_extent(inode, block, &path, 0);
2160                 if (IS_ERR(path)) {
2161                         up_read(&EXT4_I(inode)->i_data_sem);
2162                         err = PTR_ERR(path);
2163                         path = NULL;
2164                         break;
2165                 }
2166
2167                 depth = ext_depth(inode);
2168                 if (unlikely(path[depth].p_hdr == NULL)) {
2169                         up_read(&EXT4_I(inode)->i_data_sem);
2170                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2171                         err = -EIO;
2172                         break;
2173                 }
2174                 ex = path[depth].p_ext;
2175                 next = ext4_ext_next_allocated_block(path);
2176                 ext4_ext_drop_refs(path);
2177
2178                 flags = 0;
2179                 exists = 0;
2180                 if (!ex) {
2181                         /* there is no extent yet, so try to allocate
2182                          * all requested space */
2183                         start = block;
2184                         end = block + num;
2185                 } else if (le32_to_cpu(ex->ee_block) > block) {
2186                         /* need to allocate space before found extent */
2187                         start = block;
2188                         end = le32_to_cpu(ex->ee_block);
2189                         if (block + num < end)
2190                                 end = block + num;
2191                 } else if (block >= le32_to_cpu(ex->ee_block)
2192                                         + ext4_ext_get_actual_len(ex)) {
2193                         /* need to allocate space after found extent */
2194                         start = block;
2195                         end = block + num;
2196                         if (end >= next)
2197                                 end = next;
2198                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2199                         /*
2200                          * some part of requested space is covered
2201                          * by found extent
2202                          */
2203                         start = block;
2204                         end = le32_to_cpu(ex->ee_block)
2205                                 + ext4_ext_get_actual_len(ex);
2206                         if (block + num < end)
2207                                 end = block + num;
2208                         exists = 1;
2209                 } else {
2210                         BUG();
2211                 }
2212                 BUG_ON(end <= start);
2213
2214                 if (!exists) {
2215                         es.es_lblk = start;
2216                         es.es_len = end - start;
2217                         es.es_pblk = 0;
2218                 } else {
2219                         es.es_lblk = le32_to_cpu(ex->ee_block);
2220                         es.es_len = ext4_ext_get_actual_len(ex);
2221                         es.es_pblk = ext4_ext_pblock(ex);
2222                         if (ext4_ext_is_unwritten(ex))
2223                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2224                 }
2225
2226                 /*
2227                  * Find delayed extent and update es accordingly. We call
2228                  * it even in !exists case to find out whether es is the
2229                  * last existing extent or not.
2230                  */
2231                 next_del = ext4_find_delayed_extent(inode, &es);
2232                 if (!exists && next_del) {
2233                         exists = 1;
2234                         flags |= (FIEMAP_EXTENT_DELALLOC |
2235                                   FIEMAP_EXTENT_UNKNOWN);
2236                 }
2237                 up_read(&EXT4_I(inode)->i_data_sem);
2238
2239                 if (unlikely(es.es_len == 0)) {
2240                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2241                         err = -EIO;
2242                         break;
2243                 }
2244
2245                 /*
2246                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2247                  * we need to check next == EXT_MAX_BLOCKS because it is
2248                  * possible that an extent is with unwritten and delayed
2249                  * status due to when an extent is delayed allocated and
2250                  * is allocated by fallocate status tree will track both of
2251                  * them in a extent.
2252                  *
2253                  * So we could return a unwritten and delayed extent, and
2254                  * its block is equal to 'next'.
2255                  */
2256                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2257                         flags |= FIEMAP_EXTENT_LAST;
2258                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2259                                      next != EXT_MAX_BLOCKS)) {
2260                                 EXT4_ERROR_INODE(inode,
2261                                                  "next extent == %u, next "
2262                                                  "delalloc extent = %u",
2263                                                  next, next_del);
2264                                 err = -EIO;
2265                                 break;
2266                         }
2267                 }
2268
2269                 if (exists) {
2270                         err = fiemap_fill_next_extent(fieinfo,
2271                                 (__u64)es.es_lblk << blksize_bits,
2272                                 (__u64)es.es_pblk << blksize_bits,
2273                                 (__u64)es.es_len << blksize_bits,
2274                                 flags);
2275                         if (err < 0)
2276                                 break;
2277                         if (err == 1) {
2278                                 err = 0;
2279                                 break;
2280                         }
2281                 }
2282
2283                 block = es.es_lblk + es.es_len;
2284         }
2285
2286         if (path) {
2287                 ext4_ext_drop_refs(path);
2288                 kfree(path);
2289         }
2290
2291         return err;
2292 }
2293
2294 /*
2295  * ext4_ext_put_gap_in_cache:
2296  * calculate boundaries of the gap that the requested block fits into
2297  * and cache this gap
2298  */
2299 static void
2300 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
2301                                 ext4_lblk_t block)
2302 {
2303         int depth = ext_depth(inode);
2304         unsigned long len = 0;
2305         ext4_lblk_t lblock = 0;
2306         struct ext4_extent *ex;
2307
2308         ex = path[depth].p_ext;
2309         if (ex == NULL) {
2310                 /*
2311                  * there is no extent yet, so gap is [0;-] and we
2312                  * don't cache it
2313                  */
2314                 ext_debug("cache gap(whole file):");
2315         } else if (block < le32_to_cpu(ex->ee_block)) {
2316                 lblock = block;
2317                 len = le32_to_cpu(ex->ee_block) - block;
2318                 ext_debug("cache gap(before): %u [%u:%u]",
2319                                 block,
2320                                 le32_to_cpu(ex->ee_block),
2321                                  ext4_ext_get_actual_len(ex));
2322                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2323                         ext4_es_insert_extent(inode, lblock, len, ~0,
2324                                               EXTENT_STATUS_HOLE);
2325         } else if (block >= le32_to_cpu(ex->ee_block)
2326                         + ext4_ext_get_actual_len(ex)) {
2327                 ext4_lblk_t next;
2328                 lblock = le32_to_cpu(ex->ee_block)
2329                         + ext4_ext_get_actual_len(ex);
2330
2331                 next = ext4_ext_next_allocated_block(path);
2332                 ext_debug("cache gap(after): [%u:%u] %u",
2333                                 le32_to_cpu(ex->ee_block),
2334                                 ext4_ext_get_actual_len(ex),
2335                                 block);
2336                 BUG_ON(next == lblock);
2337                 len = next - lblock;
2338                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2339                         ext4_es_insert_extent(inode, lblock, len, ~0,
2340                                               EXTENT_STATUS_HOLE);
2341         } else {
2342                 BUG();
2343         }
2344
2345         ext_debug(" -> %u:%lu\n", lblock, len);
2346 }
2347
2348 /*
2349  * ext4_ext_rm_idx:
2350  * removes index from the index block.
2351  */
2352 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2353                         struct ext4_ext_path *path, int depth)
2354 {
2355         int err;
2356         ext4_fsblk_t leaf;
2357
2358         /* free index block */
2359         depth--;
2360         path = path + depth;
2361         leaf = ext4_idx_pblock(path->p_idx);
2362         if (unlikely(path->p_hdr->eh_entries == 0)) {
2363                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2364                 return -EIO;
2365         }
2366         err = ext4_ext_get_access(handle, inode, path);
2367         if (err)
2368                 return err;
2369
2370         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2371                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2372                 len *= sizeof(struct ext4_extent_idx);
2373                 memmove(path->p_idx, path->p_idx + 1, len);
2374         }
2375
2376         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2377         err = ext4_ext_dirty(handle, inode, path);
2378         if (err)
2379                 return err;
2380         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2381         trace_ext4_ext_rm_idx(inode, leaf);
2382
2383         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2384                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2385
2386         while (--depth >= 0) {
2387                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2388                         break;
2389                 path--;
2390                 err = ext4_ext_get_access(handle, inode, path);
2391                 if (err)
2392                         break;
2393                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2394                 err = ext4_ext_dirty(handle, inode, path);
2395                 if (err)
2396                         break;
2397         }
2398         return err;
2399 }
2400
2401 /*
2402  * ext4_ext_calc_credits_for_single_extent:
2403  * This routine returns max. credits that needed to insert an extent
2404  * to the extent tree.
2405  * When pass the actual path, the caller should calculate credits
2406  * under i_data_sem.
2407  */
2408 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2409                                                 struct ext4_ext_path *path)
2410 {
2411         if (path) {
2412                 int depth = ext_depth(inode);
2413                 int ret = 0;
2414
2415                 /* probably there is space in leaf? */
2416                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2417                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2418
2419                         /*
2420                          *  There are some space in the leaf tree, no
2421                          *  need to account for leaf block credit
2422                          *
2423                          *  bitmaps and block group descriptor blocks
2424                          *  and other metadata blocks still need to be
2425                          *  accounted.
2426                          */
2427                         /* 1 bitmap, 1 block group descriptor */
2428                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2429                         return ret;
2430                 }
2431         }
2432
2433         return ext4_chunk_trans_blocks(inode, nrblocks);
2434 }
2435
2436 /*
2437  * How many index/leaf blocks need to change/allocate to add @extents extents?
2438  *
2439  * If we add a single extent, then in the worse case, each tree level
2440  * index/leaf need to be changed in case of the tree split.
2441  *
2442  * If more extents are inserted, they could cause the whole tree split more
2443  * than once, but this is really rare.
2444  */
2445 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2446 {
2447         int index;
2448         int depth;
2449
2450         /* If we are converting the inline data, only one is needed here. */
2451         if (ext4_has_inline_data(inode))
2452                 return 1;
2453
2454         depth = ext_depth(inode);
2455
2456         if (extents <= 1)
2457                 index = depth * 2;
2458         else
2459                 index = depth * 3;
2460
2461         return index;
2462 }
2463
2464 static inline int get_default_free_blocks_flags(struct inode *inode)
2465 {
2466         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2467                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2468         else if (ext4_should_journal_data(inode))
2469                 return EXT4_FREE_BLOCKS_FORGET;
2470         return 0;
2471 }
2472
2473 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2474                               struct ext4_extent *ex,
2475                               long long *partial_cluster,
2476                               ext4_lblk_t from, ext4_lblk_t to)
2477 {
2478         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2479         unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2480         ext4_fsblk_t pblk;
2481         int flags = get_default_free_blocks_flags(inode);
2482
2483         /*
2484          * For bigalloc file systems, we never free a partial cluster
2485          * at the beginning of the extent.  Instead, we make a note
2486          * that we tried freeing the cluster, and check to see if we
2487          * need to free it on a subsequent call to ext4_remove_blocks,
2488          * or at the end of the ext4_truncate() operation.
2489          */
2490         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2491
2492         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2493         /*
2494          * If we have a partial cluster, and it's different from the
2495          * cluster of the last block, we need to explicitly free the
2496          * partial cluster here.
2497          */
2498         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2499         if ((*partial_cluster > 0) &&
2500             (EXT4_B2C(sbi, pblk) != *partial_cluster)) {
2501                 ext4_free_blocks(handle, inode, NULL,
2502                                  EXT4_C2B(sbi, *partial_cluster),
2503                                  sbi->s_cluster_ratio, flags);
2504                 *partial_cluster = 0;
2505         }
2506
2507 #ifdef EXTENTS_STATS
2508         {
2509                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2510                 spin_lock(&sbi->s_ext_stats_lock);
2511                 sbi->s_ext_blocks += ee_len;
2512                 sbi->s_ext_extents++;
2513                 if (ee_len < sbi->s_ext_min)
2514                         sbi->s_ext_min = ee_len;
2515                 if (ee_len > sbi->s_ext_max)
2516                         sbi->s_ext_max = ee_len;
2517                 if (ext_depth(inode) > sbi->s_depth_max)
2518                         sbi->s_depth_max = ext_depth(inode);
2519                 spin_unlock(&sbi->s_ext_stats_lock);
2520         }
2521 #endif
2522         if (from >= le32_to_cpu(ex->ee_block)
2523             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2524                 /* tail removal */
2525                 ext4_lblk_t num;
2526                 unsigned int unaligned;
2527
2528                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2529                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2530                 /*
2531                  * Usually we want to free partial cluster at the end of the
2532                  * extent, except for the situation when the cluster is still
2533                  * used by any other extent (partial_cluster is negative).
2534                  */
2535                 if (*partial_cluster < 0 &&
2536                     -(*partial_cluster) == EXT4_B2C(sbi, pblk + num - 1))
2537                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2538
2539                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2540                           num, pblk, *partial_cluster);
2541                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2542                 /*
2543                  * If the block range to be freed didn't start at the
2544                  * beginning of a cluster, and we removed the entire
2545                  * extent and the cluster is not used by any other extent,
2546                  * save the partial cluster here, since we might need to
2547                  * delete if we determine that the truncate operation has
2548                  * removed all of the blocks in the cluster.
2549                  *
2550                  * On the other hand, if we did not manage to free the whole
2551                  * extent, we have to mark the cluster as used (store negative
2552                  * cluster number in partial_cluster).
2553                  */
2554                 unaligned = EXT4_PBLK_COFF(sbi, pblk);
2555                 if (unaligned && (ee_len == num) &&
2556                     (*partial_cluster != -((long long)EXT4_B2C(sbi, pblk))))
2557                         *partial_cluster = EXT4_B2C(sbi, pblk);
2558                 else if (unaligned)
2559                         *partial_cluster = -((long long)EXT4_B2C(sbi, pblk));
2560                 else if (*partial_cluster > 0)
2561                         *partial_cluster = 0;
2562         } else
2563                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2564                            "%u-%u from %u:%u\n",
2565                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2566         return 0;
2567 }
2568
2569
2570 /*
2571  * ext4_ext_rm_leaf() Removes the extents associated with the
2572  * blocks appearing between "start" and "end", and splits the extents
2573  * if "start" and "end" appear in the same extent
2574  *
2575  * @handle: The journal handle
2576  * @inode:  The files inode
2577  * @path:   The path to the leaf
2578  * @partial_cluster: The cluster which we'll have to free if all extents
2579  *                   has been released from it. It gets negative in case
2580  *                   that the cluster is still used.
2581  * @start:  The first block to remove
2582  * @end:   The last block to remove
2583  */
2584 static int
2585 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2586                  struct ext4_ext_path *path,
2587                  long long *partial_cluster,
2588                  ext4_lblk_t start, ext4_lblk_t end)
2589 {
2590         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2591         int err = 0, correct_index = 0;
2592         int depth = ext_depth(inode), credits;
2593         struct ext4_extent_header *eh;
2594         ext4_lblk_t a, b;
2595         unsigned num;
2596         ext4_lblk_t ex_ee_block;
2597         unsigned short ex_ee_len;
2598         unsigned unwritten = 0;
2599         struct ext4_extent *ex;
2600         ext4_fsblk_t pblk;
2601
2602         /* the header must be checked already in ext4_ext_remove_space() */
2603         ext_debug("truncate since %u in leaf to %u\n", start, end);
2604         if (!path[depth].p_hdr)
2605                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2606         eh = path[depth].p_hdr;
2607         if (unlikely(path[depth].p_hdr == NULL)) {
2608                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2609                 return -EIO;
2610         }
2611         /* find where to start removing */
2612         ex = path[depth].p_ext;
2613         if (!ex)
2614                 ex = EXT_LAST_EXTENT(eh);
2615
2616         ex_ee_block = le32_to_cpu(ex->ee_block);
2617         ex_ee_len = ext4_ext_get_actual_len(ex);
2618
2619         /*
2620          * If we're starting with an extent other than the last one in the
2621          * node, we need to see if it shares a cluster with the extent to
2622          * the right (towards the end of the file). If its leftmost cluster
2623          * is this extent's rightmost cluster and it is not cluster aligned,
2624          * we'll mark it as a partial that is not to be deallocated.
2625          */
2626
2627         if (ex != EXT_LAST_EXTENT(eh)) {
2628                 ext4_fsblk_t current_pblk, right_pblk;
2629                 long long current_cluster, right_cluster;
2630
2631                 current_pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2632                 current_cluster = (long long)EXT4_B2C(sbi, current_pblk);
2633                 right_pblk = ext4_ext_pblock(ex + 1);
2634                 right_cluster = (long long)EXT4_B2C(sbi, right_pblk);
2635                 if (current_cluster == right_cluster &&
2636                         EXT4_PBLK_COFF(sbi, right_pblk))
2637                         *partial_cluster = -right_cluster;
2638         }
2639
2640         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2641
2642         while (ex >= EXT_FIRST_EXTENT(eh) &&
2643                         ex_ee_block + ex_ee_len > start) {
2644
2645                 if (ext4_ext_is_unwritten(ex))
2646                         unwritten = 1;
2647                 else
2648                         unwritten = 0;
2649
2650                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2651                           unwritten, ex_ee_len);
2652                 path[depth].p_ext = ex;
2653
2654                 a = ex_ee_block > start ? ex_ee_block : start;
2655                 b = ex_ee_block+ex_ee_len - 1 < end ?
2656                         ex_ee_block+ex_ee_len - 1 : end;
2657
2658                 ext_debug("  border %u:%u\n", a, b);
2659
2660                 /* If this extent is beyond the end of the hole, skip it */
2661                 if (end < ex_ee_block) {
2662                         /*
2663                          * We're going to skip this extent and move to another,
2664                          * so if this extent is not cluster aligned we have
2665                          * to mark the current cluster as used to avoid
2666                          * accidentally freeing it later on
2667                          */
2668                         pblk = ext4_ext_pblock(ex);
2669                         if (EXT4_PBLK_COFF(sbi, pblk))
2670                                 *partial_cluster =
2671                                         -((long long)EXT4_B2C(sbi, pblk));
2672                         ex--;
2673                         ex_ee_block = le32_to_cpu(ex->ee_block);
2674                         ex_ee_len = ext4_ext_get_actual_len(ex);
2675                         continue;
2676                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2677                         EXT4_ERROR_INODE(inode,
2678                                          "can not handle truncate %u:%u "
2679                                          "on extent %u:%u",
2680                                          start, end, ex_ee_block,
2681                                          ex_ee_block + ex_ee_len - 1);
2682                         err = -EIO;
2683                         goto out;
2684                 } else if (a != ex_ee_block) {
2685                         /* remove tail of the extent */
2686                         num = a - ex_ee_block;
2687                 } else {
2688                         /* remove whole extent: excellent! */
2689                         num = 0;
2690                 }
2691                 /*
2692                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2693                  * descriptor) for each block group; assume two block
2694                  * groups plus ex_ee_len/blocks_per_block_group for
2695                  * the worst case
2696                  */
2697                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2698                 if (ex == EXT_FIRST_EXTENT(eh)) {
2699                         correct_index = 1;
2700                         credits += (ext_depth(inode)) + 1;
2701                 }
2702                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2703
2704                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2705                 if (err)
2706                         goto out;
2707
2708                 err = ext4_ext_get_access(handle, inode, path + depth);
2709                 if (err)
2710                         goto out;
2711
2712                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2713                                          a, b);
2714                 if (err)
2715                         goto out;
2716
2717                 if (num == 0)
2718                         /* this extent is removed; mark slot entirely unused */
2719                         ext4_ext_store_pblock(ex, 0);
2720
2721                 ex->ee_len = cpu_to_le16(num);
2722                 /*
2723                  * Do not mark unwritten if all the blocks in the
2724                  * extent have been removed.
2725                  */
2726                 if (unwritten && num)
2727                         ext4_ext_mark_unwritten(ex);
2728                 /*
2729                  * If the extent was completely released,
2730                  * we need to remove it from the leaf
2731                  */
2732                 if (num == 0) {
2733                         if (end != EXT_MAX_BLOCKS - 1) {
2734                                 /*
2735                                  * For hole punching, we need to scoot all the
2736                                  * extents up when an extent is removed so that
2737                                  * we dont have blank extents in the middle
2738                                  */
2739                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2740                                         sizeof(struct ext4_extent));
2741
2742                                 /* Now get rid of the one at the end */
2743                                 memset(EXT_LAST_EXTENT(eh), 0,
2744                                         sizeof(struct ext4_extent));
2745                         }
2746                         le16_add_cpu(&eh->eh_entries, -1);
2747                 } else if (*partial_cluster > 0)
2748                         *partial_cluster = 0;
2749
2750                 err = ext4_ext_dirty(handle, inode, path + depth);
2751                 if (err)
2752                         goto out;
2753
2754                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2755                                 ext4_ext_pblock(ex));
2756                 ex--;
2757                 ex_ee_block = le32_to_cpu(ex->ee_block);
2758                 ex_ee_len = ext4_ext_get_actual_len(ex);
2759         }
2760
2761         if (correct_index && eh->eh_entries)
2762                 err = ext4_ext_correct_indexes(handle, inode, path);
2763
2764         /*
2765          * If there's a partial cluster and at least one extent remains in
2766          * the leaf, free the partial cluster if it isn't shared with the
2767          * current extent.  If there's a partial cluster and no extents
2768          * remain in the leaf, it can't be freed here.  It can only be
2769          * freed when it's possible to determine if it's not shared with
2770          * any other extent - when the next leaf is processed or when space
2771          * removal is complete.
2772          */
2773         if (*partial_cluster > 0 && eh->eh_entries &&
2774             (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) !=
2775              *partial_cluster)) {
2776                 int flags = get_default_free_blocks_flags(inode);
2777
2778                 ext4_free_blocks(handle, inode, NULL,
2779                                  EXT4_C2B(sbi, *partial_cluster),
2780                                  sbi->s_cluster_ratio, flags);
2781                 *partial_cluster = 0;
2782         }
2783
2784         /* if this leaf is free, then we should
2785          * remove it from index block above */
2786         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2787                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2788
2789 out:
2790         return err;
2791 }
2792
2793 /*
2794  * ext4_ext_more_to_rm:
2795  * returns 1 if current index has to be freed (even partial)
2796  */
2797 static int
2798 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2799 {
2800         BUG_ON(path->p_idx == NULL);
2801
2802         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2803                 return 0;
2804
2805         /*
2806          * if truncate on deeper level happened, it wasn't partial,
2807          * so we have to consider current index for truncation
2808          */
2809         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2810                 return 0;
2811         return 1;
2812 }
2813
2814 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2815                           ext4_lblk_t end)
2816 {
2817         struct super_block *sb = inode->i_sb;
2818         int depth = ext_depth(inode);
2819         struct ext4_ext_path *path = NULL;
2820         long long partial_cluster = 0;
2821         handle_t *handle;
2822         int i = 0, err = 0;
2823
2824         ext_debug("truncate since %u to %u\n", start, end);
2825
2826         /* probably first extent we're gonna free will be last in block */
2827         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2828         if (IS_ERR(handle))
2829                 return PTR_ERR(handle);
2830
2831 again:
2832         trace_ext4_ext_remove_space(inode, start, end, depth);
2833
2834         /*
2835          * Check if we are removing extents inside the extent tree. If that
2836          * is the case, we are going to punch a hole inside the extent tree
2837          * so we have to check whether we need to split the extent covering
2838          * the last block to remove so we can easily remove the part of it
2839          * in ext4_ext_rm_leaf().
2840          */
2841         if (end < EXT_MAX_BLOCKS - 1) {
2842                 struct ext4_extent *ex;
2843                 ext4_lblk_t ee_block;
2844
2845                 /* find extent for this block */
2846                 path = ext4_ext_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2847                 if (IS_ERR(path)) {
2848                         ext4_journal_stop(handle);
2849                         return PTR_ERR(path);
2850                 }
2851                 depth = ext_depth(inode);
2852                 /* Leaf not may not exist only if inode has no blocks at all */
2853                 ex = path[depth].p_ext;
2854                 if (!ex) {
2855                         if (depth) {
2856                                 EXT4_ERROR_INODE(inode,
2857                                                  "path[%d].p_hdr == NULL",
2858                                                  depth);
2859                                 err = -EIO;
2860                         }
2861                         goto out;
2862                 }
2863
2864                 ee_block = le32_to_cpu(ex->ee_block);
2865
2866                 /*
2867                  * See if the last block is inside the extent, if so split
2868                  * the extent at 'end' block so we can easily remove the
2869                  * tail of the first part of the split extent in
2870                  * ext4_ext_rm_leaf().
2871                  */
2872                 if (end >= ee_block &&
2873                     end < ee_block + ext4_ext_get_actual_len(ex) - 1) {
2874                         /*
2875                          * Split the extent in two so that 'end' is the last
2876                          * block in the first new extent. Also we should not
2877                          * fail removing space due to ENOSPC so try to use
2878                          * reserved block if that happens.
2879                          */
2880                         err = ext4_force_split_extent_at(handle, inode, &path,
2881                                                          end + 1, 1);
2882                         if (err < 0)
2883                                 goto out;
2884                 }
2885         }
2886         /*
2887          * We start scanning from right side, freeing all the blocks
2888          * after i_size and walking into the tree depth-wise.
2889          */
2890         depth = ext_depth(inode);
2891         if (path) {
2892                 int k = i = depth;
2893                 while (--k > 0)
2894                         path[k].p_block =
2895                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2896         } else {
2897                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2898                                GFP_NOFS);
2899                 if (path == NULL) {
2900                         ext4_journal_stop(handle);
2901                         return -ENOMEM;
2902                 }
2903                 path[0].p_depth = depth;
2904                 path[0].p_hdr = ext_inode_hdr(inode);
2905                 i = 0;
2906
2907                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2908                         err = -EIO;
2909                         goto out;
2910                 }
2911         }
2912         err = 0;
2913
2914         while (i >= 0 && err == 0) {
2915                 if (i == depth) {
2916                         /* this is leaf block */
2917                         err = ext4_ext_rm_leaf(handle, inode, path,
2918                                                &partial_cluster, start,
2919                                                end);
2920                         /* root level has p_bh == NULL, brelse() eats this */
2921                         brelse(path[i].p_bh);
2922                         path[i].p_bh = NULL;
2923                         i--;
2924                         continue;
2925                 }
2926
2927                 /* this is index block */
2928                 if (!path[i].p_hdr) {
2929                         ext_debug("initialize header\n");
2930                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2931                 }
2932
2933                 if (!path[i].p_idx) {
2934                         /* this level hasn't been touched yet */
2935                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2936                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2937                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2938                                   path[i].p_hdr,
2939                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2940                 } else {
2941                         /* we were already here, see at next index */
2942                         path[i].p_idx--;
2943                 }
2944
2945                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2946                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2947                                 path[i].p_idx);
2948                 if (ext4_ext_more_to_rm(path + i)) {
2949                         struct buffer_head *bh;
2950                         /* go to the next level */
2951                         ext_debug("move to level %d (block %llu)\n",
2952                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2953                         memset(path + i + 1, 0, sizeof(*path));
2954                         bh = read_extent_tree_block(inode,
2955                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2956                                 EXT4_EX_NOCACHE);
2957                         if (IS_ERR(bh)) {
2958                                 /* should we reset i_size? */
2959                                 err = PTR_ERR(bh);
2960                                 break;
2961                         }
2962                         /* Yield here to deal with large extent trees.
2963                          * Should be a no-op if we did IO above. */
2964                         cond_resched();
2965                         if (WARN_ON(i + 1 > depth)) {
2966                                 err = -EIO;
2967                                 break;
2968                         }
2969                         path[i + 1].p_bh = bh;
2970
2971                         /* save actual number of indexes since this
2972                          * number is changed at the next iteration */
2973                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2974                         i++;
2975                 } else {
2976                         /* we finished processing this index, go up */
2977                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2978                                 /* index is empty, remove it;
2979                                  * handle must be already prepared by the
2980                                  * truncatei_leaf() */
2981                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2982                         }
2983                         /* root level has p_bh == NULL, brelse() eats this */
2984                         brelse(path[i].p_bh);
2985                         path[i].p_bh = NULL;
2986                         i--;
2987                         ext_debug("return to level %d\n", i);
2988                 }
2989         }
2990
2991         trace_ext4_ext_remove_space_done(inode, start, end, depth,
2992                         partial_cluster, path->p_hdr->eh_entries);
2993
2994         /* If we still have something in the partial cluster and we have removed
2995          * even the first extent, then we should free the blocks in the partial
2996          * cluster as well. */
2997         if (partial_cluster > 0 && path->p_hdr->eh_entries == 0) {
2998                 int flags = get_default_free_blocks_flags(inode);
2999
3000                 ext4_free_blocks(handle, inode, NULL,
3001                                  EXT4_C2B(EXT4_SB(sb), partial_cluster),
3002                                  EXT4_SB(sb)->s_cluster_ratio, flags);
3003                 partial_cluster = 0;
3004         }
3005
3006         /* TODO: flexible tree reduction should be here */
3007         if (path->p_hdr->eh_entries == 0) {
3008                 /*
3009                  * truncate to zero freed all the tree,
3010                  * so we need to correct eh_depth
3011                  */
3012                 err = ext4_ext_get_access(handle, inode, path);
3013                 if (err == 0) {
3014                         ext_inode_hdr(inode)->eh_depth = 0;
3015                         ext_inode_hdr(inode)->eh_max =
3016                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3017                         err = ext4_ext_dirty(handle, inode, path);
3018                 }
3019         }
3020 out:
3021         if (path) {
3022                 ext4_ext_drop_refs(path);
3023                 kfree(path);
3024                 path = NULL;
3025         }
3026         if (err == -EAGAIN)
3027                 goto again;
3028         ext4_journal_stop(handle);
3029
3030         return err;
3031 }
3032
3033 /*
3034  * called at mount time
3035  */
3036 void ext4_ext_init(struct super_block *sb)
3037 {
3038         /*
3039          * possible initialization would be here
3040          */
3041
3042         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
3043 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3044                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3045 #ifdef AGGRESSIVE_TEST
3046                        ", aggressive tests"
3047 #endif
3048 #ifdef CHECK_BINSEARCH
3049                        ", check binsearch"
3050 #endif
3051 #ifdef EXTENTS_STATS
3052                        ", stats"
3053 #endif
3054                        "\n");
3055 #endif
3056 #ifdef EXTENTS_STATS
3057                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3058                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3059                 EXT4_SB(sb)->s_ext_max = 0;
3060 #endif
3061         }
3062 }
3063
3064 /*
3065  * called at umount time
3066  */
3067 void ext4_ext_release(struct super_block *sb)
3068 {
3069         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
3070                 return;
3071
3072 #ifdef EXTENTS_STATS
3073         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3074                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3075                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3076                         sbi->s_ext_blocks, sbi->s_ext_extents,
3077                         sbi->s_ext_blocks / sbi->s_ext_extents);
3078                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3079                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3080         }
3081 #endif
3082 }
3083
3084 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3085 {
3086         ext4_lblk_t  ee_block;
3087         ext4_fsblk_t ee_pblock;
3088         unsigned int ee_len;
3089
3090         ee_block  = le32_to_cpu(ex->ee_block);
3091         ee_len    = ext4_ext_get_actual_len(ex);
3092         ee_pblock = ext4_ext_pblock(ex);
3093
3094         if (ee_len == 0)
3095                 return 0;
3096
3097         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3098                                      EXTENT_STATUS_WRITTEN);
3099 }
3100
3101 /* FIXME!! we need to try to merge to left or right after zero-out  */
3102 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3103 {
3104         ext4_fsblk_t ee_pblock;
3105         unsigned int ee_len;
3106         int ret;
3107
3108         ee_len    = ext4_ext_get_actual_len(ex);
3109         ee_pblock = ext4_ext_pblock(ex);
3110
3111         ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
3112         if (ret > 0)
3113                 ret = 0;
3114
3115         return ret;
3116 }
3117
3118 /*
3119  * ext4_split_extent_at() splits an extent at given block.
3120  *
3121  * @handle: the journal handle
3122  * @inode: the file inode
3123  * @path: the path to the extent
3124  * @split: the logical block where the extent is splitted.
3125  * @split_flags: indicates if the extent could be zeroout if split fails, and
3126  *               the states(init or unwritten) of new extents.
3127  * @flags: flags used to insert new extent to extent tree.
3128  *
3129  *
3130  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3131  * of which are deterimined by split_flag.
3132  *
3133  * There are two cases:
3134  *  a> the extent are splitted into two extent.
3135  *  b> split is not needed, and just mark the extent.
3136  *
3137  * return 0 on success.
3138  */
3139 static int ext4_split_extent_at(handle_t *handle,
3140                              struct inode *inode,
3141                              struct ext4_ext_path **ppath,
3142                              ext4_lblk_t split,
3143                              int split_flag,
3144                              int flags)
3145 {
3146         struct ext4_ext_path *path = *ppath;
3147         ext4_fsblk_t newblock;
3148         ext4_lblk_t ee_block;
3149         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3150         struct ext4_extent *ex2 = NULL;
3151         unsigned int ee_len, depth;
3152         int err = 0;
3153
3154         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3155                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3156
3157         ext_debug("ext4_split_extents_at: inode %lu, logical"
3158                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3159
3160         ext4_ext_show_leaf(inode, path);
3161
3162         depth = ext_depth(inode);
3163         ex = path[depth].p_ext;
3164         ee_block = le32_to_cpu(ex->ee_block);
3165         ee_len = ext4_ext_get_actual_len(ex);
3166         newblock = split - ee_block + ext4_ext_pblock(ex);
3167
3168         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3169         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3170                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3171                              EXT4_EXT_MARK_UNWRIT1 |
3172                              EXT4_EXT_MARK_UNWRIT2));
3173
3174         err = ext4_ext_get_access(handle, inode, path + depth);
3175         if (err)
3176                 goto out;
3177
3178         if (split == ee_block) {
3179                 /*
3180                  * case b: block @split is the block that the extent begins with
3181                  * then we just change the state of the extent, and splitting
3182                  * is not needed.
3183                  */
3184                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3185                         ext4_ext_mark_unwritten(ex);
3186                 else
3187                         ext4_ext_mark_initialized(ex);
3188
3189                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3190                         ext4_ext_try_to_merge(handle, inode, path, ex);
3191
3192                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3193                 goto out;
3194         }
3195
3196         /* case a */
3197         memcpy(&orig_ex, ex, sizeof(orig_ex));
3198         ex->ee_len = cpu_to_le16(split - ee_block);
3199         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3200                 ext4_ext_mark_unwritten(ex);
3201
3202         /*
3203          * path may lead to new leaf, not to original leaf any more
3204          * after ext4_ext_insert_extent() returns,
3205          */
3206         err = ext4_ext_dirty(handle, inode, path + depth);
3207         if (err)
3208                 goto fix_extent_len;
3209
3210         ex2 = &newex;
3211         ex2->ee_block = cpu_to_le32(split);
3212         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3213         ext4_ext_store_pblock(ex2, newblock);
3214         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3215                 ext4_ext_mark_unwritten(ex2);
3216
3217         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3218         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3219                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3220                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3221                                 err = ext4_ext_zeroout(inode, ex2);
3222                                 zero_ex.ee_block = ex2->ee_block;
3223                                 zero_ex.ee_len = cpu_to_le16(
3224                                                 ext4_ext_get_actual_len(ex2));
3225                                 ext4_ext_store_pblock(&zero_ex,
3226                                                       ext4_ext_pblock(ex2));
3227                         } else {
3228                                 err = ext4_ext_zeroout(inode, ex);
3229                                 zero_ex.ee_block = ex->ee_block;
3230                                 zero_ex.ee_len = cpu_to_le16(
3231                                                 ext4_ext_get_actual_len(ex));
3232                                 ext4_ext_store_pblock(&zero_ex,
3233                                                       ext4_ext_pblock(ex));
3234                         }
3235                 } else {
3236                         err = ext4_ext_zeroout(inode, &orig_ex);
3237                         zero_ex.ee_block = orig_ex.ee_block;
3238                         zero_ex.ee_len = cpu_to_le16(
3239                                                 ext4_ext_get_actual_len(&orig_ex));
3240                         ext4_ext_store_pblock(&zero_ex,
3241                                               ext4_ext_pblock(&orig_ex));
3242                 }
3243
3244                 if (err)
3245                         goto fix_extent_len;
3246                 /* update the extent length and mark as initialized */
3247                 ex->ee_len = cpu_to_le16(ee_len);
3248                 ext4_ext_try_to_merge(handle, inode, path, ex);
3249                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3250                 if (err)
3251                         goto fix_extent_len;
3252
3253                 /* update extent status tree */
3254                 err = ext4_zeroout_es(inode, &zero_ex);
3255
3256                 goto out;
3257         } else if (err)
3258                 goto fix_extent_len;
3259
3260 out:
3261         ext4_ext_show_leaf(inode, path);
3262         return err;
3263
3264 fix_extent_len:
3265         ex->ee_len = orig_ex.ee_len;
3266         ext4_ext_dirty(handle, inode, path + path->p_depth);
3267         return err;
3268 }
3269
3270 /*
3271  * ext4_split_extents() splits an extent and mark extent which is covered
3272  * by @map as split_flags indicates
3273  *
3274  * It may result in splitting the extent into multiple extents (up to three)
3275  * There are three possibilities:
3276  *   a> There is no split required
3277  *   b> Splits in two extents: Split is happening at either end of the extent
3278  *   c> Splits in three extents: Somone is splitting in middle of the extent
3279  *
3280  */
3281 static int ext4_split_extent(handle_t *handle,
3282                               struct inode *inode,
3283                               struct ext4_ext_path **ppath,
3284                               struct ext4_map_blocks *map,
3285                               int split_flag,
3286                               int flags)
3287 {
3288         struct ext4_ext_path *path = *ppath;
3289         ext4_lblk_t ee_block;
3290         struct ext4_extent *ex;
3291         unsigned int ee_len, depth;
3292         int err = 0;
3293         int unwritten;
3294         int split_flag1, flags1;
3295         int allocated = map->m_len;
3296
3297         depth = ext_depth(inode);
3298         ex = path[depth].p_ext;
3299         ee_block = le32_to_cpu(ex->ee_block);
3300         ee_len = ext4_ext_get_actual_len(ex);
3301         unwritten = ext4_ext_is_unwritten(ex);
3302
3303         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3304                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3305                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3306                 if (unwritten)
3307                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3308                                        EXT4_EXT_MARK_UNWRIT2;
3309                 if (split_flag & EXT4_EXT_DATA_VALID2)
3310                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3311                 err = ext4_split_extent_at(handle, inode, ppath,
3312                                 map->m_lblk + map->m_len, split_flag1, flags1);
3313                 if (err)
3314                         goto out;
3315         } else {
3316                 allocated = ee_len - (map->m_lblk - ee_block);
3317         }
3318         /*
3319          * Update path is required because previous ext4_split_extent_at() may
3320          * result in split of original leaf or extent zeroout.
3321          */
3322         ext4_ext_drop_refs(path);
3323         path = ext4_ext_find_extent(inode, map->m_lblk, ppath, 0);
3324         if (IS_ERR(path))
3325                 return PTR_ERR(path);
3326         depth = ext_depth(inode);
3327         ex = path[depth].p_ext;
3328         if (!ex) {
3329                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3330                                  (unsigned long) map->m_lblk);
3331                 return -EIO;
3332         }
3333         unwritten = ext4_ext_is_unwritten(ex);
3334         split_flag1 = 0;
3335
3336         if (map->m_lblk >= ee_block) {
3337                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3338                 if (unwritten) {
3339                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3340                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3341                                                      EXT4_EXT_MARK_UNWRIT2);
3342                 }
3343                 err = ext4_split_extent_at(handle, inode, ppath,
3344                                 map->m_lblk, split_flag1, flags);
3345                 if (err)
3346                         goto out;
3347         }
3348
3349         ext4_ext_show_leaf(inode, path);
3350 out:
3351         return err ? err : allocated;
3352 }
3353
3354 /*
3355  * This function is called by ext4_ext_map_blocks() if someone tries to write
3356  * to an unwritten extent. It may result in splitting the unwritten
3357  * extent into multiple extents (up to three - one initialized and two
3358  * unwritten).
3359  * There are three possibilities:
3360  *   a> There is no split required: Entire extent should be initialized
3361  *   b> Splits in two extents: Write is happening at either end of the extent
3362  *   c> Splits in three extents: Somone is writing in middle of the extent
3363  *
3364  * Pre-conditions:
3365  *  - The extent pointed to by 'path' is unwritten.
3366  *  - The extent pointed to by 'path' contains a superset
3367  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3368  *
3369  * Post-conditions on success:
3370  *  - the returned value is the number of blocks beyond map->l_lblk
3371  *    that are allocated and initialized.
3372  *    It is guaranteed to be >= map->m_len.
3373  */
3374 static int ext4_ext_convert_to_initialized(handle_t *handle,
3375                                            struct inode *inode,
3376                                            struct ext4_map_blocks *map,
3377                                            struct ext4_ext_path **ppath,
3378                                            int flags)
3379 {
3380         struct ext4_ext_path *path = *ppath;
3381         struct ext4_sb_info *sbi;
3382         struct ext4_extent_header *eh;
3383         struct ext4_map_blocks split_map;
3384         struct ext4_extent zero_ex;
3385         struct ext4_extent *ex, *abut_ex;
3386         ext4_lblk_t ee_block, eof_block;
3387         unsigned int ee_len, depth, map_len = map->m_len;
3388         int allocated = 0, max_zeroout = 0;
3389         int err = 0;
3390         int split_flag = 0;
3391
3392         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3393                 "block %llu, max_blocks %u\n", inode->i_ino,
3394                 (unsigned long long)map->m_lblk, map_len);
3395
3396         sbi = EXT4_SB(inode->i_sb);
3397         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3398                 inode->i_sb->s_blocksize_bits;
3399         if (eof_block < map->m_lblk + map_len)
3400                 eof_block = map->m_lblk + map_len;
3401
3402         depth = ext_depth(inode);
3403         eh = path[depth].p_hdr;
3404         ex = path[depth].p_ext;
3405         ee_block = le32_to_cpu(ex->ee_block);
3406         ee_len = ext4_ext_get_actual_len(ex);
3407         zero_ex.ee_len = 0;
3408
3409         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3410
3411         /* Pre-conditions */
3412         BUG_ON(!ext4_ext_is_unwritten(ex));
3413         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3414
3415         /*
3416          * Attempt to transfer newly initialized blocks from the currently
3417          * unwritten extent to its neighbor. This is much cheaper
3418          * than an insertion followed by a merge as those involve costly
3419          * memmove() calls. Transferring to the left is the common case in
3420          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3421          * followed by append writes.
3422          *
3423          * Limitations of the current logic:
3424          *  - L1: we do not deal with writes covering the whole extent.
3425          *    This would require removing the extent if the transfer
3426          *    is possible.
3427          *  - L2: we only attempt to merge with an extent stored in the
3428          *    same extent tree node.
3429          */
3430         if ((map->m_lblk == ee_block) &&
3431                 /* See if we can merge left */
3432                 (map_len < ee_len) &&           /*L1*/
3433                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3434                 ext4_lblk_t prev_lblk;
3435                 ext4_fsblk_t prev_pblk, ee_pblk;
3436                 unsigned int prev_len;
3437
3438                 abut_ex = ex - 1;
3439                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3440                 prev_len = ext4_ext_get_actual_len(abut_ex);
3441                 prev_pblk = ext4_ext_pblock(abut_ex);
3442                 ee_pblk = ext4_ext_pblock(ex);
3443
3444                 /*
3445                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3446                  * upon those conditions:
3447                  * - C1: abut_ex is initialized,
3448                  * - C2: abut_ex is logically abutting ex,
3449                  * - C3: abut_ex is physically abutting ex,
3450                  * - C4: abut_ex can receive the additional blocks without
3451                  *   overflowing the (initialized) length limit.
3452                  */
3453                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3454                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3455                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3456                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3457                         err = ext4_ext_get_access(handle, inode, path + depth);
3458                         if (err)
3459                                 goto out;
3460
3461                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3462                                 map, ex, abut_ex);
3463
3464                         /* Shift the start of ex by 'map_len' blocks */
3465                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3466                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3467                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3468                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3469
3470                         /* Extend abut_ex by 'map_len' blocks */
3471                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3472
3473                         /* Result: number of initialized blocks past m_lblk */
3474                         allocated = map_len;
3475                 }
3476         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3477                    (map_len < ee_len) &&        /*L1*/
3478                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3479                 /* See if we can merge right */
3480                 ext4_lblk_t next_lblk;
3481                 ext4_fsblk_t next_pblk, ee_pblk;
3482                 unsigned int next_len;
3483
3484                 abut_ex = ex + 1;
3485                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3486                 next_len = ext4_ext_get_actual_len(abut_ex);
3487                 next_pblk = ext4_ext_pblock(abut_ex);
3488                 ee_pblk = ext4_ext_pblock(ex);
3489
3490                 /*
3491                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3492                  * upon those conditions:
3493                  * - C1: abut_ex is initialized,
3494                  * - C2: abut_ex is logically abutting ex,
3495                  * - C3: abut_ex is physically abutting ex,
3496                  * - C4: abut_ex can receive the additional blocks without
3497                  *   overflowing the (initialized) length limit.
3498                  */
3499                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3500                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3501                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3502                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3503                         err = ext4_ext_get_access(handle, inode, path + depth);
3504                         if (err)
3505                                 goto out;
3506
3507                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3508                                 map, ex, abut_ex);
3509
3510                         /* Shift the start of abut_ex by 'map_len' blocks */
3511                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3512                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3513                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3514                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3515
3516                         /* Extend abut_ex by 'map_len' blocks */
3517                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3518
3519                         /* Result: number of initialized blocks past m_lblk */
3520                         allocated = map_len;
3521                 }
3522         }
3523         if (allocated) {
3524                 /* Mark the block containing both extents as dirty */
3525                 ext4_ext_dirty(handle, inode, path + depth);
3526
3527                 /* Update path to point to the right extent */
3528                 path[depth].p_ext = abut_ex;
3529                 goto out;
3530         } else
3531                 allocated = ee_len - (map->m_lblk - ee_block);
3532
3533         WARN_ON(map->m_lblk < ee_block);
3534         /*
3535          * It is safe to convert extent to initialized via explicit
3536          * zeroout only if extent is fully inside i_size or new_size.
3537          */
3538         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3539
3540         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3541                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3542                         (inode->i_sb->s_blocksize_bits - 10);
3543
3544         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3545         if (max_zeroout && (ee_len <= max_zeroout)) {
3546                 err = ext4_ext_zeroout(inode, ex);
3547                 if (err)
3548                         goto out;
3549                 zero_ex.ee_block = ex->ee_block;
3550                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3551                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3552
3553                 err = ext4_ext_get_access(handle, inode, path + depth);
3554                 if (err)
3555                         goto out;
3556                 ext4_ext_mark_initialized(ex);
3557                 ext4_ext_try_to_merge(handle, inode, path, ex);
3558                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3559                 goto out;
3560         }
3561
3562         /*
3563          * four cases:
3564          * 1. split the extent into three extents.
3565          * 2. split the extent into two extents, zeroout the first half.
3566          * 3. split the extent into two extents, zeroout the second half.
3567          * 4. split the extent into two extents with out zeroout.
3568          */
3569         split_map.m_lblk = map->m_lblk;
3570         split_map.m_len = map->m_len;
3571
3572         if (max_zeroout && (allocated > map->m_len)) {
3573                 if (allocated <= max_zeroout) {
3574                         /* case 3 */
3575                         zero_ex.ee_block =
3576                                          cpu_to_le32(map->m_lblk);
3577                         zero_ex.ee_len = cpu_to_le16(allocated);
3578                         ext4_ext_store_pblock(&zero_ex,
3579                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3580                         err = ext4_ext_zeroout(inode, &zero_ex);
3581                         if (err)
3582                                 goto out;
3583                         split_map.m_lblk = map->m_lblk;
3584                         split_map.m_len = allocated;
3585                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3586                         /* case 2 */
3587                         if (map->m_lblk != ee_block) {
3588                                 zero_ex.ee_block = ex->ee_block;
3589                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3590                                                         ee_block);
3591                                 ext4_ext_store_pblock(&zero_ex,
3592                                                       ext4_ext_pblock(ex));
3593                                 err = ext4_ext_zeroout(inode, &zero_ex);
3594                                 if (err)
3595                                         goto out;
3596                         }
3597
3598                         split_map.m_lblk = ee_block;
3599                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3600                         allocated = map->m_len;
3601                 }
3602         }
3603
3604         allocated = ext4_split_extent(handle, inode, ppath,
3605                                       &split_map, split_flag, flags);
3606         if (allocated < 0)
3607                 err = allocated;
3608
3609 out:
3610         /* If we have gotten a failure, don't zero out status tree */
3611         if (!err)
3612                 err = ext4_zeroout_es(inode, &zero_ex);
3613         return err ? err : allocated;
3614 }
3615
3616 /*
3617  * This function is called by ext4_ext_map_blocks() from
3618  * ext4_get_blocks_dio_write() when DIO to write
3619  * to an unwritten extent.
3620  *
3621  * Writing to an unwritten extent may result in splitting the unwritten
3622  * extent into multiple initialized/unwritten extents (up to three)
3623  * There are three possibilities:
3624  *   a> There is no split required: Entire extent should be unwritten
3625  *   b> Splits in two extents: Write is happening at either end of the extent
3626  *   c> Splits in three extents: Somone is writing in middle of the extent
3627  *
3628  * This works the same way in the case of initialized -> unwritten conversion.
3629  *
3630  * One of more index blocks maybe needed if the extent tree grow after
3631  * the unwritten extent split. To prevent ENOSPC occur at the IO
3632  * complete, we need to split the unwritten extent before DIO submit
3633  * the IO. The unwritten extent called at this time will be split
3634  * into three unwritten extent(at most). After IO complete, the part
3635  * being filled will be convert to initialized by the end_io callback function
3636  * via ext4_convert_unwritten_extents().
3637  *
3638  * Returns the size of unwritten extent to be written on success.
3639  */
3640 static int ext4_split_convert_extents(handle_t *handle,
3641                                         struct inode *inode,
3642                                         struct ext4_map_blocks *map,
3643                                         struct ext4_ext_path **ppath,
3644                                         int flags)
3645 {
3646         struct ext4_ext_path *path = *ppath;
3647         ext4_lblk_t eof_block;
3648         ext4_lblk_t ee_block;
3649         struct ext4_extent *ex;
3650         unsigned int ee_len;
3651         int split_flag = 0, depth;
3652
3653         ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3654                   __func__, inode->i_ino,
3655                   (unsigned long long)map->m_lblk, map->m_len);
3656
3657         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3658                 inode->i_sb->s_blocksize_bits;
3659         if (eof_block < map->m_lblk + map->m_len)
3660                 eof_block = map->m_lblk + map->m_len;
3661         /*
3662          * It is safe to convert extent to initialized via explicit
3663          * zeroout only if extent is fully insde i_size or new_size.
3664          */
3665         depth = ext_depth(inode);
3666         ex = path[depth].p_ext;
3667         ee_block = le32_to_cpu(ex->ee_block);
3668         ee_len = ext4_ext_get_actual_len(ex);
3669
3670         /* Convert to unwritten */
3671         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3672                 split_flag |= EXT4_EXT_DATA_VALID1;
3673         /* Convert to initialized */
3674         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3675                 split_flag |= ee_block + ee_len <= eof_block ?
3676                               EXT4_EXT_MAY_ZEROOUT : 0;
3677                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3678         }
3679         flags |= EXT4_GET_BLOCKS_PRE_IO;
3680         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3681 }
3682
3683 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3684                                                 struct inode *inode,
3685                                                 struct ext4_map_blocks *map,
3686                                                 struct ext4_ext_path **ppath)
3687 {
3688         struct ext4_ext_path *path = *ppath;
3689         struct ext4_extent *ex;
3690         ext4_lblk_t ee_block;
3691         unsigned int ee_len;
3692         int depth;
3693         int err = 0;
3694
3695         depth = ext_depth(inode);
3696         ex = path[depth].p_ext;
3697         ee_block = le32_to_cpu(ex->ee_block);
3698         ee_len = ext4_ext_get_actual_len(ex);
3699
3700         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3701                 "block %llu, max_blocks %u\n", inode->i_ino,
3702                   (unsigned long long)ee_block, ee_len);
3703
3704         /* If extent is larger than requested it is a clear sign that we still
3705          * have some extent state machine issues left. So extent_split is still
3706          * required.
3707          * TODO: Once all related issues will be fixed this situation should be
3708          * illegal.
3709          */
3710         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3711 #ifdef EXT4_DEBUG
3712                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3713                              " len %u; IO logical block %llu, len %u\n",
3714                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3715                              (unsigned long long)map->m_lblk, map->m_len);
3716 #endif
3717                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3718                                                  EXT4_GET_BLOCKS_CONVERT);
3719                 if (err < 0)
3720                         return err;
3721                 ext4_ext_drop_refs(path);
3722                 path = ext4_ext_find_extent(inode, map->m_lblk, ppath, 0);
3723                 if (IS_ERR(path))
3724                         return PTR_ERR(path);
3725                 depth = ext_depth(inode);
3726                 ex = path[depth].p_ext;
3727         }
3728
3729         err = ext4_ext_get_access(handle, inode, path + depth);
3730         if (err)
3731                 goto out;
3732         /* first mark the extent as initialized */
3733         ext4_ext_mark_initialized(ex);
3734
3735         /* note: ext4_ext_correct_indexes() isn't needed here because
3736          * borders are not changed
3737          */
3738         ext4_ext_try_to_merge(handle, inode, path, ex);
3739
3740         /* Mark modified extent as dirty */
3741         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3742 out:
3743         ext4_ext_show_leaf(inode, path);
3744         return err;
3745 }
3746
3747 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3748                         sector_t block, int count)
3749 {
3750         int i;
3751         for (i = 0; i < count; i++)
3752                 unmap_underlying_metadata(bdev, block + i);
3753 }
3754
3755 /*
3756  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3757  */
3758 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3759                               ext4_lblk_t lblk,
3760                               struct ext4_ext_path *path,
3761                               unsigned int len)
3762 {
3763         int i, depth;
3764         struct ext4_extent_header *eh;
3765         struct ext4_extent *last_ex;
3766
3767         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3768                 return 0;
3769
3770         depth = ext_depth(inode);
3771         eh = path[depth].p_hdr;
3772
3773         /*
3774          * We're going to remove EOFBLOCKS_FL entirely in future so we
3775          * do not care for this case anymore. Simply remove the flag
3776          * if there are no extents.
3777          */
3778         if (unlikely(!eh->eh_entries))
3779                 goto out;
3780         last_ex = EXT_LAST_EXTENT(eh);
3781         /*
3782          * We should clear the EOFBLOCKS_FL flag if we are writing the
3783          * last block in the last extent in the file.  We test this by
3784          * first checking to see if the caller to
3785          * ext4_ext_get_blocks() was interested in the last block (or
3786          * a block beyond the last block) in the current extent.  If
3787          * this turns out to be false, we can bail out from this
3788          * function immediately.
3789          */
3790         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3791             ext4_ext_get_actual_len(last_ex))
3792                 return 0;
3793         /*
3794          * If the caller does appear to be planning to write at or
3795          * beyond the end of the current extent, we then test to see
3796          * if the current extent is the last extent in the file, by
3797          * checking to make sure it was reached via the rightmost node
3798          * at each level of the tree.
3799          */
3800         for (i = depth-1; i >= 0; i--)
3801                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3802                         return 0;
3803 out:
3804         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3805         return ext4_mark_inode_dirty(handle, inode);
3806 }
3807
3808 /**
3809  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3810  *
3811  * Return 1 if there is a delalloc block in the range, otherwise 0.
3812  */
3813 int ext4_find_delalloc_range(struct inode *inode,
3814                              ext4_lblk_t lblk_start,
3815                              ext4_lblk_t lblk_end)
3816 {
3817         struct extent_status es;
3818
3819         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3820         if (es.es_len == 0)
3821                 return 0; /* there is no delay extent in this tree */
3822         else if (es.es_lblk <= lblk_start &&
3823                  lblk_start < es.es_lblk + es.es_len)
3824                 return 1;
3825         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3826                 return 1;
3827         else
3828                 return 0;
3829 }
3830
3831 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3832 {
3833         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3834         ext4_lblk_t lblk_start, lblk_end;
3835         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3836         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3837
3838         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3839 }
3840
3841 /**
3842  * Determines how many complete clusters (out of those specified by the 'map')
3843  * are under delalloc and were reserved quota for.
3844  * This function is called when we are writing out the blocks that were
3845  * originally written with their allocation delayed, but then the space was
3846  * allocated using fallocate() before the delayed allocation could be resolved.
3847  * The cases to look for are:
3848  * ('=' indicated delayed allocated blocks
3849  *  '-' indicates non-delayed allocated blocks)
3850  * (a) partial clusters towards beginning and/or end outside of allocated range
3851  *     are not delalloc'ed.
3852  *      Ex:
3853  *      |----c---=|====c====|====c====|===-c----|
3854  *               |++++++ allocated ++++++|
3855  *      ==> 4 complete clusters in above example
3856  *
3857  * (b) partial cluster (outside of allocated range) towards either end is
3858  *     marked for delayed allocation. In this case, we will exclude that
3859  *     cluster.
3860  *      Ex:
3861  *      |----====c========|========c========|
3862  *           |++++++ allocated ++++++|
3863  *      ==> 1 complete clusters in above example
3864  *
3865  *      Ex:
3866  *      |================c================|
3867  *            |++++++ allocated ++++++|
3868  *      ==> 0 complete clusters in above example
3869  *
3870  * The ext4_da_update_reserve_space will be called only if we
3871  * determine here that there were some "entire" clusters that span
3872  * this 'allocated' range.
3873  * In the non-bigalloc case, this function will just end up returning num_blks
3874  * without ever calling ext4_find_delalloc_range.
3875  */
3876 static unsigned int
3877 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3878                            unsigned int num_blks)
3879 {
3880         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3881         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3882         ext4_lblk_t lblk_from, lblk_to, c_offset;
3883         unsigned int allocated_clusters = 0;
3884
3885         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3886         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3887
3888         /* max possible clusters for this allocation */
3889         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3890
3891         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3892
3893         /* Check towards left side */
3894         c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3895         if (c_offset) {
3896                 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3897                 lblk_to = lblk_from + c_offset - 1;
3898
3899                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3900                         allocated_clusters--;
3901         }
3902
3903         /* Now check towards right. */
3904         c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3905         if (allocated_clusters && c_offset) {
3906                 lblk_from = lblk_start + num_blks;
3907                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3908
3909                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3910                         allocated_clusters--;
3911         }
3912
3913         return allocated_clusters;
3914 }
3915
3916 static int
3917 convert_initialized_extent(handle_t *handle, struct inode *inode,
3918                            struct ext4_map_blocks *map,
3919                            struct ext4_ext_path **ppath, int flags,
3920                            unsigned int allocated, ext4_fsblk_t newblock)
3921 {
3922         struct ext4_ext_path *path = *ppath;
3923         struct ext4_extent *ex;
3924         ext4_lblk_t ee_block;
3925         unsigned int ee_len;
3926         int depth;
3927         int err = 0;
3928
3929         /*
3930          * Make sure that the extent is no bigger than we support with
3931          * unwritten extent
3932          */
3933         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3934                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3935
3936         depth = ext_depth(inode);
3937         ex = path[depth].p_ext;
3938         ee_block = le32_to_cpu(ex->ee_block);
3939         ee_len = ext4_ext_get_actual_len(ex);
3940
3941         ext_debug("%s: inode %lu, logical"
3942                 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3943                   (unsigned long long)ee_block, ee_len);
3944
3945         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3946                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3947                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3948                 if (err < 0)
3949                         return err;
3950                 ext4_ext_drop_refs(path);
3951                 path = ext4_ext_find_extent(inode, map->m_lblk, ppath, 0);
3952                 if (IS_ERR(path))
3953                         return PTR_ERR(path);
3954                 depth = ext_depth(inode);
3955                 ex = path[depth].p_ext;
3956                 if (!ex) {
3957                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3958                                          (unsigned long) map->m_lblk);
3959                         return -EIO;
3960                 }
3961         }
3962
3963         err = ext4_ext_get_access(handle, inode, path + depth);
3964         if (err)
3965                 return err;
3966         /* first mark the extent as unwritten */
3967         ext4_ext_mark_unwritten(ex);
3968
3969         /* note: ext4_ext_correct_indexes() isn't needed here because
3970          * borders are not changed
3971          */
3972         ext4_ext_try_to_merge(handle, inode, path, ex);
3973
3974         /* Mark modified extent as dirty */
3975         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3976         if (err)
3977                 return err;
3978         ext4_ext_show_leaf(inode, path);
3979
3980         ext4_update_inode_fsync_trans(handle, inode, 1);
3981         err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
3982         if (err)
3983                 return err;
3984         map->m_flags |= EXT4_MAP_UNWRITTEN;
3985         if (allocated > map->m_len)
3986                 allocated = map->m_len;
3987         map->m_len = allocated;
3988         return allocated;
3989 }
3990
3991 static int
3992 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3993                         struct ext4_map_blocks *map,
3994                         struct ext4_ext_path **ppath, int flags,
3995                         unsigned int allocated, ext4_fsblk_t newblock)
3996 {
3997         struct ext4_ext_path *path = *ppath;
3998         int ret = 0;
3999         int err = 0;
4000         ext4_io_end_t *io = ext4_inode_aio(inode);
4001
4002         ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4003                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
4004                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4005                   flags, allocated);
4006         ext4_ext_show_leaf(inode, path);
4007
4008         /*
4009          * When writing into unwritten space, we should not fail to
4010          * allocate metadata blocks for the new extent block if needed.
4011          */
4012         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4013
4014         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4015                                                     allocated, newblock);
4016
4017         /* get_block() before submit the IO, split the extent */
4018         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4019                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4020                                          flags | EXT4_GET_BLOCKS_CONVERT);
4021                 if (ret <= 0)
4022                         goto out;
4023                 /*
4024                  * Flag the inode(non aio case) or end_io struct (aio case)
4025                  * that this IO needs to conversion to written when IO is
4026                  * completed
4027                  */
4028                 if (io)
4029                         ext4_set_io_unwritten_flag(inode, io);
4030                 else
4031                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
4032                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4033                 goto out;
4034         }
4035         /* IO end_io complete, convert the filled extent to written */
4036         if (flags & EXT4_GET_BLOCKS_CONVERT) {
4037                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4038                                                            ppath);
4039                 if (ret >= 0) {
4040                         ext4_update_inode_fsync_trans(handle, inode, 1);
4041                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
4042                                                  path, map->m_len);
4043                 } else
4044                         err = ret;
4045                 map->m_flags |= EXT4_MAP_MAPPED;
4046                 map->m_pblk = newblock;
4047                 if (allocated > map->m_len)
4048                         allocated = map->m_len;
4049                 map->m_len = allocated;
4050                 goto out2;
4051         }
4052         /* buffered IO case */
4053         /*
4054          * repeat fallocate creation request
4055          * we already have an unwritten extent
4056          */
4057         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4058                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4059                 goto map_out;
4060         }
4061
4062         /* buffered READ or buffered write_begin() lookup */
4063         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4064                 /*
4065                  * We have blocks reserved already.  We
4066                  * return allocated blocks so that delalloc
4067                  * won't do block reservation for us.  But
4068                  * the buffer head will be unmapped so that
4069                  * a read from the block returns 0s.
4070                  */
4071                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4072                 goto out1;
4073         }
4074
4075         /* buffered write, writepage time, convert*/
4076         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4077         if (ret >= 0)
4078                 ext4_update_inode_fsync_trans(handle, inode, 1);
4079 out:
4080         if (ret <= 0) {
4081                 err = ret;
4082                 goto out2;
4083         } else
4084                 allocated = ret;
4085         map->m_flags |= EXT4_MAP_NEW;
4086         /*
4087          * if we allocated more blocks than requested
4088          * we need to make sure we unmap the extra block
4089          * allocated. The actual needed block will get
4090          * unmapped later when we find the buffer_head marked
4091          * new.
4092          */
4093         if (allocated > map->m_len) {
4094                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4095                                         newblock + map->m_len,
4096                                         allocated - map->m_len);
4097                 allocated = map->m_len;
4098         }
4099         map->m_len = allocated;
4100
4101         /*
4102          * If we have done fallocate with the offset that is already
4103          * delayed allocated, we would have block reservation
4104          * and quota reservation done in the delayed write path.
4105          * But fallocate would have already updated quota and block
4106          * count for this offset. So cancel these reservation
4107          */
4108         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4109                 unsigned int reserved_clusters;
4110                 reserved_clusters = get_reserved_cluster_alloc(inode,
4111                                 map->m_lblk, map->m_len);
4112                 if (reserved_clusters)
4113                         ext4_da_update_reserve_space(inode,
4114                                                      reserved_clusters,
4115                                                      0);
4116         }
4117
4118 map_out:
4119         map->m_flags |= EXT4_MAP_MAPPED;
4120         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4121                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4122                                          map->m_len);
4123                 if (err < 0)
4124                         goto out2;
4125         }
4126 out1:
4127         if (allocated > map->m_len)
4128                 allocated = map->m_len;
4129         ext4_ext_show_leaf(inode, path);
4130         map->m_pblk = newblock;
4131         map->m_len = allocated;
4132 out2:
4133         return err ? err : allocated;
4134 }
4135
4136 /*
4137  * get_implied_cluster_alloc - check to see if the requested
4138  * allocation (in the map structure) overlaps with a cluster already
4139  * allocated in an extent.
4140  *      @sb     The filesystem superblock structure
4141  *      @map    The requested lblk->pblk mapping
4142  *      @ex     The extent structure which might contain an implied
4143  *                      cluster allocation
4144  *
4145  * This function is called by ext4_ext_map_blocks() after we failed to
4146  * find blocks that were already in the inode's extent tree.  Hence,
4147  * we know that the beginning of the requested region cannot overlap
4148  * the extent from the inode's extent tree.  There are three cases we
4149  * want to catch.  The first is this case:
4150  *
4151  *               |--- cluster # N--|
4152  *    |--- extent ---|  |---- requested region ---|
4153  *                      |==========|
4154  *
4155  * The second case that we need to test for is this one:
4156  *
4157  *   |--------- cluster # N ----------------|
4158  *         |--- requested region --|   |------- extent ----|
4159  *         |=======================|
4160  *
4161  * The third case is when the requested region lies between two extents
4162  * within the same cluster:
4163  *          |------------- cluster # N-------------|
4164  * |----- ex -----|                  |---- ex_right ----|
4165  *                  |------ requested region ------|
4166  *                  |================|
4167  *
4168  * In each of the above cases, we need to set the map->m_pblk and
4169  * map->m_len so it corresponds to the return the extent labelled as
4170  * "|====|" from cluster #N, since it is already in use for data in
4171  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4172  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4173  * as a new "allocated" block region.  Otherwise, we will return 0 and
4174  * ext4_ext_map_blocks() will then allocate one or more new clusters
4175  * by calling ext4_mb_new_blocks().
4176  */
4177 static int get_implied_cluster_alloc(struct super_block *sb,
4178                                      struct ext4_map_blocks *map,
4179                                      struct ext4_extent *ex,
4180                                      struct ext4_ext_path *path)
4181 {
4182         struct ext4_sb_info *sbi = EXT4_SB(sb);
4183         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4184         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4185         ext4_lblk_t rr_cluster_start;
4186         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4187         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4188         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4189
4190         /* The extent passed in that we are trying to match */
4191         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4192         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4193
4194         /* The requested region passed into ext4_map_blocks() */
4195         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4196
4197         if ((rr_cluster_start == ex_cluster_end) ||
4198             (rr_cluster_start == ex_cluster_start)) {
4199                 if (rr_cluster_start == ex_cluster_end)
4200                         ee_start += ee_len - 1;
4201                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4202                 map->m_len = min(map->m_len,
4203                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4204                 /*
4205                  * Check for and handle this case:
4206                  *
4207                  *   |--------- cluster # N-------------|
4208                  *                     |------- extent ----|
4209                  *         |--- requested region ---|
4210                  *         |===========|
4211                  */
4212
4213                 if (map->m_lblk < ee_block)
4214                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4215
4216                 /*
4217                  * Check for the case where there is already another allocated
4218                  * block to the right of 'ex' but before the end of the cluster.
4219                  *
4220                  *          |------------- cluster # N-------------|
4221                  * |----- ex -----|                  |---- ex_right ----|
4222                  *                  |------ requested region ------|
4223                  *                  |================|
4224                  */
4225                 if (map->m_lblk > ee_block) {
4226                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4227                         map->m_len = min(map->m_len, next - map->m_lblk);
4228                 }
4229
4230                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4231                 return 1;
4232         }
4233
4234         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4235         return 0;
4236 }
4237
4238
4239 /*
4240  * Block allocation/map/preallocation routine for extents based files
4241  *
4242  *
4243  * Need to be called with
4244  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4245  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4246  *
4247  * return > 0, number of of blocks already mapped/allocated
4248  *          if create == 0 and these are pre-allocated blocks
4249  *              buffer head is unmapped
4250  *          otherwise blocks are mapped
4251  *
4252  * return = 0, if plain look up failed (blocks have not been allocated)
4253  *          buffer head is unmapped
4254  *
4255  * return < 0, error case.
4256  */
4257 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4258                         struct ext4_map_blocks *map, int flags)
4259 {
4260         struct ext4_ext_path *path = NULL;
4261         struct ext4_extent newex, *ex, *ex2;
4262         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4263         ext4_fsblk_t newblock = 0;
4264         int free_on_err = 0, err = 0, depth, ret;
4265         unsigned int allocated = 0, offset = 0;
4266         unsigned int allocated_clusters = 0;
4267         struct ext4_allocation_request ar;
4268         ext4_io_end_t *io = ext4_inode_aio(inode);
4269         ext4_lblk_t cluster_offset;
4270         int set_unwritten = 0;
4271
4272         ext_debug("blocks %u/%u requested for inode %lu\n",
4273                   map->m_lblk, map->m_len, inode->i_ino);
4274         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4275
4276         /* find extent for this block */
4277         path = ext4_ext_find_extent(inode, map->m_lblk, NULL, 0);
4278         if (IS_ERR(path)) {
4279                 err = PTR_ERR(path);
4280                 path = NULL;
4281                 goto out2;
4282         }
4283
4284         depth = ext_depth(inode);
4285
4286         /*
4287          * consistent leaf must not be empty;
4288          * this situation is possible, though, _during_ tree modification;
4289          * this is why assert can't be put in ext4_ext_find_extent()
4290          */
4291         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4292                 EXT4_ERROR_INODE(inode, "bad extent address "
4293                                  "lblock: %lu, depth: %d pblock %lld",
4294                                  (unsigned long) map->m_lblk, depth,
4295                                  path[depth].p_block);
4296                 err = -EIO;
4297                 goto out2;
4298         }
4299
4300         ex = path[depth].p_ext;
4301         if (ex) {
4302                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4303                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4304                 unsigned short ee_len;
4305
4306
4307                 /*
4308                  * unwritten extents are treated as holes, except that
4309                  * we split out initialized portions during a write.
4310                  */
4311                 ee_len = ext4_ext_get_actual_len(ex);
4312
4313                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4314
4315                 /* if found extent covers block, simply return it */
4316                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4317                         newblock = map->m_lblk - ee_block + ee_start;
4318                         /* number of remaining blocks in the extent */
4319                         allocated = ee_len - (map->m_lblk - ee_block);
4320                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4321                                   ee_block, ee_len, newblock);
4322
4323                         /*
4324                          * If the extent is initialized check whether the
4325                          * caller wants to convert it to unwritten.
4326                          */
4327                         if ((!ext4_ext_is_unwritten(ex)) &&
4328                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4329                                 allocated = convert_initialized_extent(
4330                                                 handle, inode, map, &path,
4331                                                 flags, allocated, newblock);
4332                                 goto out2;
4333                         } else if (!ext4_ext_is_unwritten(ex))
4334                                 goto out;
4335
4336                         ret = ext4_ext_handle_unwritten_extents(
4337                                 handle, inode, map, &path, flags,
4338                                 allocated, newblock);
4339                         if (ret < 0)
4340                                 err = ret;
4341                         else
4342                                 allocated = ret;
4343                         goto out2;
4344                 }
4345         }
4346
4347         if ((sbi->s_cluster_ratio > 1) &&
4348             ext4_find_delalloc_cluster(inode, map->m_lblk))
4349                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4350
4351         /*
4352          * requested block isn't allocated yet;
4353          * we couldn't try to create block if create flag is zero
4354          */
4355         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4356                 /*
4357                  * put just found gap into cache to speed up
4358                  * subsequent requests
4359                  */
4360                 if ((flags & EXT4_GET_BLOCKS_NO_PUT_HOLE) == 0)
4361                         ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
4362                 goto out2;
4363         }
4364
4365         /*
4366          * Okay, we need to do block allocation.
4367          */
4368         map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
4369         newex.ee_block = cpu_to_le32(map->m_lblk);
4370         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4371
4372         /*
4373          * If we are doing bigalloc, check to see if the extent returned
4374          * by ext4_ext_find_extent() implies a cluster we can use.
4375          */
4376         if (cluster_offset && ex &&
4377             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4378                 ar.len = allocated = map->m_len;
4379                 newblock = map->m_pblk;
4380                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4381                 goto got_allocated_blocks;
4382         }
4383
4384         /* find neighbour allocated blocks */
4385         ar.lleft = map->m_lblk;
4386         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4387         if (err)
4388                 goto out2;
4389         ar.lright = map->m_lblk;
4390         ex2 = NULL;
4391         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4392         if (err)
4393                 goto out2;
4394
4395         /* Check if the extent after searching to the right implies a
4396          * cluster we can use. */
4397         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4398             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4399                 ar.len = allocated = map->m_len;
4400                 newblock = map->m_pblk;
4401                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4402                 goto got_allocated_blocks;
4403         }
4404
4405         /*
4406          * See if request is beyond maximum number of blocks we can have in
4407          * a single extent. For an initialized extent this limit is
4408          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4409          * EXT_UNWRITTEN_MAX_LEN.
4410          */
4411         if (map->m_len > EXT_INIT_MAX_LEN &&
4412             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4413                 map->m_len = EXT_INIT_MAX_LEN;
4414         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4415                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4416                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4417
4418         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4419         newex.ee_len = cpu_to_le16(map->m_len);
4420         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4421         if (err)
4422                 allocated = ext4_ext_get_actual_len(&newex);
4423         else
4424                 allocated = map->m_len;
4425
4426         /* allocate new block */
4427         ar.inode = inode;
4428         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4429         ar.logical = map->m_lblk;
4430         /*
4431          * We calculate the offset from the beginning of the cluster
4432          * for the logical block number, since when we allocate a
4433          * physical cluster, the physical block should start at the
4434          * same offset from the beginning of the cluster.  This is
4435          * needed so that future calls to get_implied_cluster_alloc()
4436          * work correctly.
4437          */
4438         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4439         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4440         ar.goal -= offset;
4441         ar.logical -= offset;
4442         if (S_ISREG(inode->i_mode))
4443                 ar.flags = EXT4_MB_HINT_DATA;
4444         else
4445                 /* disable in-core preallocation for non-regular files */
4446                 ar.flags = 0;
4447         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4448                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4449         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4450         if (!newblock)
4451                 goto out2;
4452         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4453                   ar.goal, newblock, allocated);
4454         free_on_err = 1;
4455         allocated_clusters = ar.len;
4456         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4457         if (ar.len > allocated)
4458                 ar.len = allocated;
4459
4460 got_allocated_blocks:
4461         /* try to insert new extent into found leaf and return */
4462         ext4_ext_store_pblock(&newex, newblock + offset);
4463         newex.ee_len = cpu_to_le16(ar.len);
4464         /* Mark unwritten */
4465         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4466                 ext4_ext_mark_unwritten(&newex);
4467                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4468                 /*
4469                  * io_end structure was created for every IO write to an
4470                  * unwritten extent. To avoid unnecessary conversion,
4471                  * here we flag the IO that really needs the conversion.
4472                  * For non asycn direct IO case, flag the inode state
4473                  * that we need to perform conversion when IO is done.
4474                  */
4475                 if (flags & EXT4_GET_BLOCKS_PRE_IO)
4476                         set_unwritten = 1;
4477         }
4478
4479         err = 0;
4480         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4481                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4482                                          path, ar.len);
4483         if (!err)
4484                 err = ext4_ext_insert_extent(handle, inode, &path,
4485                                              &newex, flags);
4486
4487         if (!err && set_unwritten) {
4488                 if (io)
4489                         ext4_set_io_unwritten_flag(inode, io);
4490                 else
4491                         ext4_set_inode_state(inode,
4492                                              EXT4_STATE_DIO_UNWRITTEN);
4493         }
4494
4495         if (err && free_on_err) {
4496                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4497                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4498                 /* free data blocks we just allocated */
4499                 /* not a good idea to call discard here directly,
4500                  * but otherwise we'd need to call it every free() */
4501                 ext4_discard_preallocations(inode);
4502                 ext4_free_blocks(handle, inode, NULL, newblock,
4503                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4504                 goto out2;
4505         }
4506
4507         /* previous routine could use block we allocated */
4508         newblock = ext4_ext_pblock(&newex);
4509         allocated = ext4_ext_get_actual_len(&newex);
4510         if (allocated > map->m_len)
4511                 allocated = map->m_len;
4512         map->m_flags |= EXT4_MAP_NEW;
4513
4514         /*
4515          * Update reserved blocks/metadata blocks after successful
4516          * block allocation which had been deferred till now.
4517          */
4518         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4519                 unsigned int reserved_clusters;
4520                 /*
4521                  * Check how many clusters we had reserved this allocated range
4522                  */
4523                 reserved_clusters = get_reserved_cluster_alloc(inode,
4524                                                 map->m_lblk, allocated);
4525                 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) {
4526                         if (reserved_clusters) {
4527                                 /*
4528                                  * We have clusters reserved for this range.
4529                                  * But since we are not doing actual allocation
4530                                  * and are simply using blocks from previously
4531                                  * allocated cluster, we should release the
4532                                  * reservation and not claim quota.
4533                                  */
4534                                 ext4_da_update_reserve_space(inode,
4535                                                 reserved_clusters, 0);
4536                         }
4537                 } else {
4538                         BUG_ON(allocated_clusters < reserved_clusters);
4539                         if (reserved_clusters < allocated_clusters) {
4540                                 struct ext4_inode_info *ei = EXT4_I(inode);
4541                                 int reservation = allocated_clusters -
4542                                                   reserved_clusters;
4543                                 /*
4544                                  * It seems we claimed few clusters outside of
4545                                  * the range of this allocation. We should give
4546                                  * it back to the reservation pool. This can
4547                                  * happen in the following case:
4548                                  *
4549                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4550                                  *   cluster has 4 blocks. Thus, the clusters
4551                                  *   are [0-3],[4-7],[8-11]...
4552                                  * * First comes delayed allocation write for
4553                                  *   logical blocks 10 & 11. Since there were no
4554                                  *   previous delayed allocated blocks in the
4555                                  *   range [8-11], we would reserve 1 cluster
4556                                  *   for this write.
4557                                  * * Next comes write for logical blocks 3 to 8.
4558                                  *   In this case, we will reserve 2 clusters
4559                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4560                                  *   that range has a delayed allocated blocks.
4561                                  *   Thus total reserved clusters now becomes 3.
4562                                  * * Now, during the delayed allocation writeout
4563                                  *   time, we will first write blocks [3-8] and
4564                                  *   allocate 3 clusters for writing these
4565                                  *   blocks. Also, we would claim all these
4566                                  *   three clusters above.
4567                                  * * Now when we come here to writeout the
4568                                  *   blocks [10-11], we would expect to claim
4569                                  *   the reservation of 1 cluster we had made
4570                                  *   (and we would claim it since there are no
4571                                  *   more delayed allocated blocks in the range
4572                                  *   [8-11]. But our reserved cluster count had
4573                                  *   already gone to 0.
4574                                  *
4575                                  *   Thus, at the step 4 above when we determine
4576                                  *   that there are still some unwritten delayed
4577                                  *   allocated blocks outside of our current
4578                                  *   block range, we should increment the
4579                                  *   reserved clusters count so that when the
4580                                  *   remaining blocks finally gets written, we
4581                                  *   could claim them.
4582                                  */
4583                                 dquot_reserve_block(inode,
4584                                                 EXT4_C2B(sbi, reservation));
4585                                 spin_lock(&ei->i_block_reservation_lock);
4586                                 ei->i_reserved_data_blocks += reservation;
4587                                 spin_unlock(&ei->i_block_reservation_lock);
4588                         }
4589                         /*
4590                          * We will claim quota for all newly allocated blocks.
4591                          * We're updating the reserved space *after* the
4592                          * correction above so we do not accidentally free
4593                          * all the metadata reservation because we might
4594                          * actually need it later on.
4595                          */
4596                         ext4_da_update_reserve_space(inode, allocated_clusters,
4597                                                         1);
4598                 }
4599         }
4600
4601         /*
4602          * Cache the extent and update transaction to commit on fdatasync only
4603          * when it is _not_ an unwritten extent.
4604          */
4605         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4606                 ext4_update_inode_fsync_trans(handle, inode, 1);
4607         else
4608                 ext4_update_inode_fsync_trans(handle, inode, 0);
4609 out:
4610         if (allocated > map->m_len)
4611                 allocated = map->m_len;
4612         ext4_ext_show_leaf(inode, path);
4613         map->m_flags |= EXT4_MAP_MAPPED;
4614         map->m_pblk = newblock;
4615         map->m_len = allocated;
4616 out2:
4617         if (path) {
4618                 ext4_ext_drop_refs(path);
4619                 kfree(path);
4620         }
4621
4622         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4623                                        err ? err : allocated);
4624         ext4_es_lru_add(inode);
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         struct ext4_map_blocks map;
4672         unsigned int credits;
4673         loff_t epos;
4674
4675         map.m_lblk = offset;
4676         map.m_len = len;
4677         /*
4678          * Don't normalize the request if it can fit in one extent so
4679          * that it doesn't get unnecessarily split into multiple
4680          * extents.
4681          */
4682         if (len <= EXT_UNWRITTEN_MAX_LEN)
4683                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4684
4685         /*
4686          * credits to insert 1 extent into extent tree
4687          */
4688         credits = ext4_chunk_trans_blocks(inode, len);
4689
4690 retry:
4691         while (ret >= 0 && len) {
4692                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4693                                             credits);
4694                 if (IS_ERR(handle)) {
4695                         ret = PTR_ERR(handle);
4696                         break;
4697                 }
4698                 ret = ext4_map_blocks(handle, inode, &map, flags);
4699                 if (ret <= 0) {
4700                         ext4_debug("inode #%lu: block %u: len %u: "
4701                                    "ext4_ext_map_blocks returned %d",
4702                                    inode->i_ino, map.m_lblk,
4703                                    map.m_len, ret);
4704                         ext4_mark_inode_dirty(handle, inode);
4705                         ret2 = ext4_journal_stop(handle);
4706                         break;
4707                 }
4708                 map.m_lblk += ret;
4709                 map.m_len = len = len - ret;
4710                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4711                 inode->i_ctime = ext4_current_time(inode);
4712                 if (new_size) {
4713                         if (epos > new_size)
4714                                 epos = new_size;
4715                         if (ext4_update_inode_size(inode, epos) & 0x1)
4716                                 inode->i_mtime = inode->i_ctime;
4717                 } else {
4718                         if (epos > inode->i_size)
4719                                 ext4_set_inode_flag(inode,
4720                                                     EXT4_INODE_EOFBLOCKS);
4721                 }
4722                 ext4_mark_inode_dirty(handle, inode);
4723                 ret2 = ext4_journal_stop(handle);
4724                 if (ret2)
4725                         break;
4726         }
4727         if (ret == -ENOSPC &&
4728                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4729                 ret = 0;
4730                 goto retry;
4731         }
4732
4733         return ret > 0 ? ret2 : ret;
4734 }
4735
4736 static long ext4_zero_range(struct file *file, loff_t offset,
4737                             loff_t len, int mode)
4738 {
4739         struct inode *inode = file_inode(file);
4740         handle_t *handle = NULL;
4741         unsigned int max_blocks;
4742         loff_t new_size = 0;
4743         int ret = 0;
4744         int flags;
4745         int credits;
4746         int partial_begin, partial_end;
4747         loff_t start, end;
4748         ext4_lblk_t lblk;
4749         struct address_space *mapping = inode->i_mapping;
4750         unsigned int blkbits = inode->i_blkbits;
4751
4752         trace_ext4_zero_range(inode, offset, len, mode);
4753
4754         if (!S_ISREG(inode->i_mode))
4755                 return -EINVAL;
4756
4757         /* Call ext4_force_commit to flush all data in case of data=journal. */
4758         if (ext4_should_journal_data(inode)) {
4759                 ret = ext4_force_commit(inode->i_sb);
4760                 if (ret)
4761                         return ret;
4762         }
4763
4764         /*
4765          * Write out all dirty pages to avoid race conditions
4766          * Then release them.
4767          */
4768         if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4769                 ret = filemap_write_and_wait_range(mapping, offset,
4770                                                    offset + len - 1);
4771                 if (ret)
4772                         return ret;
4773         }
4774
4775         /*
4776          * Round up offset. This is not fallocate, we neet to zero out
4777          * blocks, so convert interior block aligned part of the range to
4778          * unwritten and possibly manually zero out unaligned parts of the
4779          * range.
4780          */
4781         start = round_up(offset, 1 << blkbits);
4782         end = round_down((offset + len), 1 << blkbits);
4783
4784         if (start < offset || end > offset + len)
4785                 return -EINVAL;
4786         partial_begin = offset & ((1 << blkbits) - 1);
4787         partial_end = (offset + len) & ((1 << blkbits) - 1);
4788
4789         lblk = start >> blkbits;
4790         max_blocks = (end >> blkbits);
4791         if (max_blocks < lblk)
4792                 max_blocks = 0;
4793         else
4794                 max_blocks -= lblk;
4795
4796         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT |
4797                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4798                 EXT4_EX_NOCACHE;
4799         if (mode & FALLOC_FL_KEEP_SIZE)
4800                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4801
4802         mutex_lock(&inode->i_mutex);
4803
4804         /*
4805          * Indirect files do not support unwritten extnets
4806          */
4807         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4808                 ret = -EOPNOTSUPP;
4809                 goto out_mutex;
4810         }
4811
4812         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4813              offset + len > i_size_read(inode)) {
4814                 new_size = offset + len;
4815                 ret = inode_newsize_ok(inode, new_size);
4816                 if (ret)
4817                         goto out_mutex;
4818                 /*
4819                  * If we have a partial block after EOF we have to allocate
4820                  * the entire block.
4821                  */
4822                 if (partial_end)
4823                         max_blocks += 1;
4824         }
4825
4826         if (max_blocks > 0) {
4827
4828                 /* Now release the pages and zero block aligned part of pages*/
4829                 truncate_pagecache_range(inode, start, end - 1);
4830                 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4831
4832                 /* Wait all existing dio workers, newcomers will block on i_mutex */
4833                 ext4_inode_block_unlocked_dio(inode);
4834                 inode_dio_wait(inode);
4835
4836                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4837                                              flags, mode);
4838                 if (ret)
4839                         goto out_dio;
4840                 /*
4841                  * Remove entire range from the extent status tree.
4842                  *
4843                  * ext4_es_remove_extent(inode, lblk, max_blocks) is
4844                  * NOT sufficient.  I'm not sure why this is the case,
4845                  * but let's be conservative and remove the extent
4846                  * status tree for the entire inode.  There should be
4847                  * no outstanding delalloc extents thanks to the
4848                  * filemap_write_and_wait_range() call above.
4849                  */
4850                 ret = ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
4851                 if (ret)
4852                         goto out_dio;
4853         }
4854         if (!partial_begin && !partial_end)
4855                 goto out_dio;
4856
4857         /*
4858          * In worst case we have to writeout two nonadjacent unwritten
4859          * blocks and update the inode
4860          */
4861         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4862         if (ext4_should_journal_data(inode))
4863                 credits += 2;
4864         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4865         if (IS_ERR(handle)) {
4866                 ret = PTR_ERR(handle);
4867                 ext4_std_error(inode->i_sb, ret);
4868                 goto out_dio;
4869         }
4870
4871         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4872         if (new_size) {
4873                 ext4_update_inode_size(inode, new_size);
4874         } else {
4875                 /*
4876                 * Mark that we allocate beyond EOF so the subsequent truncate
4877                 * can proceed even if the new size is the same as i_size.
4878                 */
4879                 if ((offset + len) > i_size_read(inode))
4880                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4881         }
4882         ext4_mark_inode_dirty(handle, inode);
4883
4884         /* Zero out partial block at the edges of the range */
4885         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4886
4887         if (file->f_flags & O_SYNC)
4888                 ext4_handle_sync(handle);
4889
4890         ext4_journal_stop(handle);
4891 out_dio:
4892         ext4_inode_resume_unlocked_dio(inode);
4893 out_mutex:
4894         mutex_unlock(&inode->i_mutex);
4895         return ret;
4896 }
4897
4898 /*
4899  * preallocate space for a file. This implements ext4's fallocate file
4900  * operation, which gets called from sys_fallocate system call.
4901  * For block-mapped files, posix_fallocate should fall back to the method
4902  * of writing zeroes to the required new blocks (the same behavior which is
4903  * expected for file systems which do not support fallocate() system call).
4904  */
4905 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4906 {
4907         struct inode *inode = file_inode(file);
4908         loff_t new_size = 0;
4909         unsigned int max_blocks;
4910         int ret = 0;
4911         int flags;
4912         ext4_lblk_t lblk;
4913         unsigned int blkbits = inode->i_blkbits;
4914
4915         /* Return error if mode is not supported */
4916         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4917                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
4918                 return -EOPNOTSUPP;
4919
4920         if (mode & FALLOC_FL_PUNCH_HOLE)
4921                 return ext4_punch_hole(inode, offset, len);
4922
4923         ret = ext4_convert_inline_data(inode);
4924         if (ret)
4925                 return ret;
4926
4927         /*
4928          * currently supporting (pre)allocate mode for extent-based
4929          * files _only_
4930          */
4931         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4932                 return -EOPNOTSUPP;
4933
4934         if (mode & FALLOC_FL_COLLAPSE_RANGE)
4935                 return ext4_collapse_range(inode, offset, len);
4936
4937         if (mode & FALLOC_FL_ZERO_RANGE)
4938                 return ext4_zero_range(file, offset, len, mode);
4939
4940         trace_ext4_fallocate_enter(inode, offset, len, mode);
4941         lblk = offset >> blkbits;
4942         /*
4943          * We can't just convert len to max_blocks because
4944          * If blocksize = 4096 offset = 3072 and len = 2048
4945          */
4946         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4947                 - lblk;
4948
4949         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4950         if (mode & FALLOC_FL_KEEP_SIZE)
4951                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4952
4953         mutex_lock(&inode->i_mutex);
4954
4955         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4956              offset + len > i_size_read(inode)) {
4957                 new_size = offset + len;
4958                 ret = inode_newsize_ok(inode, new_size);
4959                 if (ret)
4960                         goto out;
4961         }
4962
4963         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4964                                      flags, mode);
4965         if (ret)
4966                 goto out;
4967
4968         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4969                 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
4970                                                 EXT4_I(inode)->i_sync_tid);
4971         }
4972 out:
4973         mutex_unlock(&inode->i_mutex);
4974         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4975         return ret;
4976 }
4977
4978 /*
4979  * This function convert a range of blocks to written extents
4980  * The caller of this function will pass the start offset and the size.
4981  * all unwritten extents within this range will be converted to
4982  * written extents.
4983  *
4984  * This function is called from the direct IO end io call back
4985  * function, to convert the fallocated extents after IO is completed.
4986  * Returns 0 on success.
4987  */
4988 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4989                                    loff_t offset, ssize_t len)
4990 {
4991         unsigned int max_blocks;
4992         int ret = 0;
4993         int ret2 = 0;
4994         struct ext4_map_blocks map;
4995         unsigned int credits, blkbits = inode->i_blkbits;
4996
4997         map.m_lblk = offset >> blkbits;
4998         /*
4999          * We can't just convert len to max_blocks because
5000          * If blocksize = 4096 offset = 3072 and len = 2048
5001          */
5002         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
5003                       map.m_lblk);
5004         /*
5005          * This is somewhat ugly but the idea is clear: When transaction is
5006          * reserved, everything goes into it. Otherwise we rather start several
5007          * smaller transactions for conversion of each extent separately.
5008          */
5009         if (handle) {
5010                 handle = ext4_journal_start_reserved(handle,
5011                                                      EXT4_HT_EXT_CONVERT);
5012                 if (IS_ERR(handle))
5013                         return PTR_ERR(handle);
5014                 credits = 0;
5015         } else {
5016                 /*
5017                  * credits to insert 1 extent into extent tree
5018                  */
5019                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5020         }
5021         while (ret >= 0 && ret < max_blocks) {
5022                 map.m_lblk += ret;
5023                 map.m_len = (max_blocks -= ret);
5024                 if (credits) {
5025                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5026                                                     credits);
5027                         if (IS_ERR(handle)) {
5028                                 ret = PTR_ERR(handle);
5029                                 break;
5030                         }
5031                 }
5032                 ret = ext4_map_blocks(handle, inode, &map,
5033                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5034                 if (ret <= 0)
5035                         ext4_warning(inode->i_sb,
5036                                      "inode #%lu: block %u: len %u: "
5037                                      "ext4_ext_map_blocks returned %d",
5038                                      inode->i_ino, map.m_lblk,
5039                                      map.m_len, ret);
5040                 ext4_mark_inode_dirty(handle, inode);
5041                 if (credits)
5042                         ret2 = ext4_journal_stop(handle);
5043                 if (ret <= 0 || ret2)
5044                         break;
5045         }
5046         if (!credits)
5047                 ret2 = ext4_journal_stop(handle);
5048         return ret > 0 ? ret2 : ret;
5049 }
5050
5051 /*
5052  * If newes is not existing extent (newes->ec_pblk equals zero) find
5053  * delayed extent at start of newes and update newes accordingly and
5054  * return start of the next delayed extent.
5055  *
5056  * If newes is existing extent (newes->ec_pblk is not equal zero)
5057  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5058  * extent found. Leave newes unmodified.
5059  */
5060 static int ext4_find_delayed_extent(struct inode *inode,
5061                                     struct extent_status *newes)
5062 {
5063         struct extent_status es;
5064         ext4_lblk_t block, next_del;
5065
5066         if (newes->es_pblk == 0) {
5067                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5068                                 newes->es_lblk + newes->es_len - 1, &es);
5069
5070                 /*
5071                  * No extent in extent-tree contains block @newes->es_pblk,
5072                  * then the block may stay in 1)a hole or 2)delayed-extent.
5073                  */
5074                 if (es.es_len == 0)
5075                         /* A hole found. */
5076                         return 0;
5077
5078                 if (es.es_lblk > newes->es_lblk) {
5079                         /* A hole found. */
5080                         newes->es_len = min(es.es_lblk - newes->es_lblk,
5081                                             newes->es_len);
5082                         return 0;
5083                 }
5084
5085                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5086         }
5087
5088         block = newes->es_lblk + newes->es_len;
5089         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5090         if (es.es_len == 0)
5091                 next_del = EXT_MAX_BLOCKS;
5092         else
5093                 next_del = es.es_lblk;
5094
5095         return next_del;
5096 }
5097 /* fiemap flags we can handle specified here */
5098 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5099
5100 static int ext4_xattr_fiemap(struct inode *inode,
5101                                 struct fiemap_extent_info *fieinfo)
5102 {
5103         __u64 physical = 0;
5104         __u64 length;
5105         __u32 flags = FIEMAP_EXTENT_LAST;
5106         int blockbits = inode->i_sb->s_blocksize_bits;
5107         int error = 0;
5108
5109         /* in-inode? */
5110         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5111                 struct ext4_iloc iloc;
5112                 int offset;     /* offset of xattr in inode */
5113
5114                 error = ext4_get_inode_loc(inode, &iloc);
5115                 if (error)
5116                         return error;
5117                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5118                 offset = EXT4_GOOD_OLD_INODE_SIZE +
5119                                 EXT4_I(inode)->i_extra_isize;
5120                 physical += offset;
5121                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5122                 flags |= FIEMAP_EXTENT_DATA_INLINE;
5123                 brelse(iloc.bh);
5124         } else { /* external block */
5125                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5126                 length = inode->i_sb->s_blocksize;
5127         }
5128
5129         if (physical)
5130                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5131                                                 length, flags);
5132         return (error < 0 ? error : 0);
5133 }
5134
5135 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5136                 __u64 start, __u64 len)
5137 {
5138         ext4_lblk_t start_blk;
5139         int error = 0;
5140
5141         if (ext4_has_inline_data(inode)) {
5142                 int has_inline = 1;
5143
5144                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline);
5145
5146                 if (has_inline)
5147                         return error;
5148         }
5149
5150         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5151                 error = ext4_ext_precache(inode);
5152                 if (error)
5153                         return error;
5154         }
5155
5156         /* fallback to generic here if not in extents fmt */
5157         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5158                 return generic_block_fiemap(inode, fieinfo, start, len,
5159                         ext4_get_block);
5160
5161         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5162                 return -EBADR;
5163
5164         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5165                 error = ext4_xattr_fiemap(inode, fieinfo);
5166         } else {
5167                 ext4_lblk_t len_blks;
5168                 __u64 last_blk;
5169
5170                 start_blk = start >> inode->i_sb->s_blocksize_bits;
5171                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5172                 if (last_blk >= EXT_MAX_BLOCKS)
5173                         last_blk = EXT_MAX_BLOCKS-1;
5174                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5175
5176                 /*
5177                  * Walk the extent tree gathering extent information
5178                  * and pushing extents back to the user.
5179                  */
5180                 error = ext4_fill_fiemap_extents(inode, start_blk,
5181                                                  len_blks, fieinfo);
5182         }
5183         ext4_es_lru_add(inode);
5184         return error;
5185 }
5186
5187 /*
5188  * ext4_access_path:
5189  * Function to access the path buffer for marking it dirty.
5190  * It also checks if there are sufficient credits left in the journal handle
5191  * to update path.
5192  */
5193 static int
5194 ext4_access_path(handle_t *handle, struct inode *inode,
5195                 struct ext4_ext_path *path)
5196 {
5197         int credits, err;
5198
5199         if (!ext4_handle_valid(handle))
5200                 return 0;
5201
5202         /*
5203          * Check if need to extend journal credits
5204          * 3 for leaf, sb, and inode plus 2 (bmap and group
5205          * descriptor) for each block group; assume two block
5206          * groups
5207          */
5208         if (handle->h_buffer_credits < 7) {
5209                 credits = ext4_writepage_trans_blocks(inode);
5210                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5211                 /* EAGAIN is success */
5212                 if (err && err != -EAGAIN)
5213                         return err;
5214         }
5215
5216         err = ext4_ext_get_access(handle, inode, path);
5217         return err;
5218 }
5219
5220 /*
5221  * ext4_ext_shift_path_extents:
5222  * Shift the extents of a path structure lying between path[depth].p_ext
5223  * and EXT_LAST_EXTENT(path[depth].p_hdr) downwards, by subtracting shift
5224  * from starting block for each extent.
5225  */
5226 static int
5227 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5228                             struct inode *inode, handle_t *handle,
5229                             ext4_lblk_t *start)
5230 {
5231         int depth, err = 0;
5232         struct ext4_extent *ex_start, *ex_last;
5233         bool update = 0;
5234         depth = path->p_depth;
5235
5236         while (depth >= 0) {
5237                 if (depth == path->p_depth) {
5238                         ex_start = path[depth].p_ext;
5239                         if (!ex_start)
5240                                 return -EIO;
5241
5242                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5243                         if (!ex_last)
5244                                 return -EIO;
5245
5246                         err = ext4_access_path(handle, inode, path + depth);
5247                         if (err)
5248                                 goto out;
5249
5250                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5251                                 update = 1;
5252
5253                         *start = le32_to_cpu(ex_last->ee_block) +
5254                                 ext4_ext_get_actual_len(ex_last);
5255
5256                         while (ex_start <= ex_last) {
5257                                 le32_add_cpu(&ex_start->ee_block, -shift);
5258                                 /* Try to merge to the left. */
5259                                 if ((ex_start >
5260                                      EXT_FIRST_EXTENT(path[depth].p_hdr)) &&
5261                                     ext4_ext_try_to_merge_right(inode,
5262                                                         path, ex_start - 1))
5263                                         ex_last--;
5264                                 else
5265                                         ex_start++;
5266                         }
5267                         err = ext4_ext_dirty(handle, inode, path + depth);
5268                         if (err)
5269                                 goto out;
5270
5271                         if (--depth < 0 || !update)
5272                                 break;
5273                 }
5274
5275                 /* Update index too */
5276                 err = ext4_access_path(handle, inode, path + depth);
5277                 if (err)
5278                         goto out;
5279
5280                 le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5281                 err = ext4_ext_dirty(handle, inode, path + depth);
5282                 if (err)
5283                         goto out;
5284
5285                 /* we are done if current index is not a starting index */
5286                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5287                         break;
5288
5289                 depth--;
5290         }
5291
5292 out:
5293         return err;
5294 }
5295
5296 /*
5297  * ext4_ext_shift_extents:
5298  * All the extents which lies in the range from start to the last allocated
5299  * block for the file are shifted downwards by shift blocks.
5300  * On success, 0 is returned, error otherwise.
5301  */
5302 static int
5303 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5304                        ext4_lblk_t start, ext4_lblk_t shift)
5305 {
5306         struct ext4_ext_path *path;
5307         int ret = 0, depth;
5308         struct ext4_extent *extent;
5309         ext4_lblk_t stop_block;
5310         ext4_lblk_t ex_start, ex_end;
5311
5312         /* Let path point to the last extent */
5313         path = ext4_ext_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
5314         if (IS_ERR(path))
5315                 return PTR_ERR(path);
5316
5317         depth = path->p_depth;
5318         extent = path[depth].p_ext;
5319         if (!extent) {
5320                 ext4_ext_drop_refs(path);
5321                 kfree(path);
5322                 return ret;
5323         }
5324
5325         stop_block = le32_to_cpu(extent->ee_block) +
5326                         ext4_ext_get_actual_len(extent);
5327         ext4_ext_drop_refs(path);
5328         kfree(path);
5329
5330         /* Nothing to shift, if hole is at the end of file */
5331         if (start >= stop_block)
5332                 return ret;
5333
5334         /*
5335          * Don't start shifting extents until we make sure the hole is big
5336          * enough to accomodate the shift.
5337          */
5338         path = ext4_ext_find_extent(inode, start - 1, NULL, 0);
5339         if (IS_ERR(path))
5340                 return PTR_ERR(path);
5341         depth = path->p_depth;
5342         extent =  path[depth].p_ext;
5343         if (extent) {
5344                 ex_start = le32_to_cpu(extent->ee_block);
5345                 ex_end = le32_to_cpu(extent->ee_block) +
5346                         ext4_ext_get_actual_len(extent);
5347         } else {
5348                 ex_start = 0;
5349                 ex_end = 0;
5350         }
5351         ext4_ext_drop_refs(path);
5352         kfree(path);
5353
5354         if ((start == ex_start && shift > ex_start) ||
5355             (shift > start - ex_end))
5356                 return -EINVAL;
5357
5358         /* Its safe to start updating extents */
5359         while (start < stop_block) {
5360                 path = ext4_ext_find_extent(inode, start, NULL, 0);
5361                 if (IS_ERR(path))
5362                         return PTR_ERR(path);
5363                 depth = path->p_depth;
5364                 extent = path[depth].p_ext;
5365                 if (!extent) {
5366                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5367                                          (unsigned long) start);
5368                         return -EIO;
5369                 }
5370                 if (start > le32_to_cpu(extent->ee_block)) {
5371                         /* Hole, move to the next extent */
5372                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5373                                 path[depth].p_ext++;
5374                         } else {
5375                                 start = ext4_ext_next_allocated_block(path);
5376                                 ext4_ext_drop_refs(path);
5377                                 kfree(path);
5378                                 continue;
5379                         }
5380                 }
5381                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5382                                 handle, &start);
5383                 ext4_ext_drop_refs(path);
5384                 kfree(path);
5385                 if (ret)
5386                         break;
5387         }
5388
5389         return ret;
5390 }
5391
5392 /*
5393  * ext4_collapse_range:
5394  * This implements the fallocate's collapse range functionality for ext4
5395  * Returns: 0 and non-zero on error.
5396  */
5397 int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5398 {
5399         struct super_block *sb = inode->i_sb;
5400         ext4_lblk_t punch_start, punch_stop;
5401         handle_t *handle;
5402         unsigned int credits;
5403         loff_t new_size, ioffset;
5404         int ret;
5405
5406         /* Collapse range works only on fs block size aligned offsets. */
5407         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5408             len & (EXT4_CLUSTER_SIZE(sb) - 1))
5409                 return -EINVAL;
5410
5411         if (!S_ISREG(inode->i_mode))
5412                 return -EINVAL;
5413
5414         trace_ext4_collapse_range(inode, offset, len);
5415
5416         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5417         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5418
5419         /* Call ext4_force_commit to flush all data in case of data=journal. */
5420         if (ext4_should_journal_data(inode)) {
5421                 ret = ext4_force_commit(inode->i_sb);
5422                 if (ret)
5423                         return ret;
5424         }
5425
5426         /*
5427          * Need to round down offset to be aligned with page size boundary
5428          * for page size > block size.
5429          */
5430         ioffset = round_down(offset, PAGE_SIZE);
5431
5432         /* Write out all dirty pages */
5433         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5434                                            LLONG_MAX);
5435         if (ret)
5436                 return ret;
5437
5438         /* Take mutex lock */
5439         mutex_lock(&inode->i_mutex);
5440
5441         /*
5442          * There is no need to overlap collapse range with EOF, in which case
5443          * it is effectively a truncate operation
5444          */
5445         if (offset + len >= i_size_read(inode)) {
5446                 ret = -EINVAL;
5447                 goto out_mutex;
5448         }
5449
5450         /* Currently just for extent based files */
5451         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5452                 ret = -EOPNOTSUPP;
5453                 goto out_mutex;
5454         }
5455
5456         truncate_pagecache(inode, ioffset);
5457
5458         /* Wait for existing dio to complete */
5459         ext4_inode_block_unlocked_dio(inode);
5460         inode_dio_wait(inode);
5461
5462         credits = ext4_writepage_trans_blocks(inode);
5463         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5464         if (IS_ERR(handle)) {
5465                 ret = PTR_ERR(handle);
5466                 goto out_dio;
5467         }
5468
5469         down_write(&EXT4_I(inode)->i_data_sem);
5470         ext4_discard_preallocations(inode);
5471
5472         ret = ext4_es_remove_extent(inode, punch_start,
5473                                     EXT_MAX_BLOCKS - punch_start);
5474         if (ret) {
5475                 up_write(&EXT4_I(inode)->i_data_sem);
5476                 goto out_stop;
5477         }
5478
5479         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5480         if (ret) {
5481                 up_write(&EXT4_I(inode)->i_data_sem);
5482                 goto out_stop;
5483         }
5484         ext4_discard_preallocations(inode);
5485
5486         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5487                                      punch_stop - punch_start);
5488         if (ret) {
5489                 up_write(&EXT4_I(inode)->i_data_sem);
5490                 goto out_stop;
5491         }
5492
5493         new_size = i_size_read(inode) - len;
5494         i_size_write(inode, new_size);
5495         EXT4_I(inode)->i_disksize = new_size;
5496
5497         up_write(&EXT4_I(inode)->i_data_sem);
5498         if (IS_SYNC(inode))
5499                 ext4_handle_sync(handle);
5500         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5501         ext4_mark_inode_dirty(handle, inode);
5502
5503 out_stop:
5504         ext4_journal_stop(handle);
5505 out_dio:
5506         ext4_inode_resume_unlocked_dio(inode);
5507 out_mutex:
5508         mutex_unlock(&inode->i_mutex);
5509         return ret;
5510 }
5511
5512 /**
5513  * ext4_swap_extents - Swap extents between two inodes
5514  *
5515  * @inode1:     First inode
5516  * @inode2:     Second inode
5517  * @lblk1:      Start block for first inode
5518  * @lblk2:      Start block for second inode
5519  * @count:      Number of blocks to swap
5520  * @mark_unwritten: Mark second inode's extents as unwritten after swap
5521  * @erp:        Pointer to save error value
5522  *
5523  * This helper routine does exactly what is promise "swap extents". All other
5524  * stuff such as page-cache locking consistency, bh mapping consistency or
5525  * extent's data copying must be performed by caller.
5526  * Locking:
5527  *              i_mutex is held for both inodes
5528  *              i_data_sem is locked for write for both inodes
5529  * Assumptions:
5530  *              All pages from requested range are locked for both inodes
5531  */
5532 int
5533 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5534                      struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5535                   ext4_lblk_t count, int unwritten, int *erp)
5536 {
5537         struct ext4_ext_path *path1 = NULL;
5538         struct ext4_ext_path *path2 = NULL;
5539         int replaced_count = 0;
5540
5541         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5542         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5543         BUG_ON(!mutex_is_locked(&inode1->i_mutex));
5544         BUG_ON(!mutex_is_locked(&inode1->i_mutex));
5545
5546         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5547         if (unlikely(*erp))
5548                 return 0;
5549         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5550         if (unlikely(*erp))
5551                 return 0;
5552
5553         while (count) {
5554                 struct ext4_extent *ex1, *ex2, tmp_ex;
5555                 ext4_lblk_t e1_blk, e2_blk;
5556                 int e1_len, e2_len, len;
5557                 int split = 0;
5558
5559                 path1 = ext4_ext_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5560                 if (unlikely(IS_ERR(path1))) {
5561                         *erp = PTR_ERR(path1);
5562                         path1 = NULL;
5563                 finish:
5564                         count = 0;
5565                         goto repeat;
5566                 }
5567                 path2 = ext4_ext_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5568                 if (unlikely(IS_ERR(path2))) {
5569                         *erp = PTR_ERR(path2);
5570                         path2 = NULL;
5571                         goto finish;
5572                 }
5573                 ex1 = path1[path1->p_depth].p_ext;
5574                 ex2 = path2[path2->p_depth].p_ext;
5575                 /* Do we have somthing to swap ? */
5576                 if (unlikely(!ex2 || !ex1))
5577                         goto finish;
5578
5579                 e1_blk = le32_to_cpu(ex1->ee_block);
5580                 e2_blk = le32_to_cpu(ex2->ee_block);
5581                 e1_len = ext4_ext_get_actual_len(ex1);
5582                 e2_len = ext4_ext_get_actual_len(ex2);
5583
5584                 /* Hole handling */
5585                 if (!in_range(lblk1, e1_blk, e1_len) ||
5586                     !in_range(lblk2, e2_blk, e2_len)) {
5587                         ext4_lblk_t next1, next2;
5588
5589                         /* if hole after extent, then go to next extent */
5590                         next1 = ext4_ext_next_allocated_block(path1);
5591                         next2 = ext4_ext_next_allocated_block(path2);
5592                         /* If hole before extent, then shift to that extent */
5593                         if (e1_blk > lblk1)
5594                                 next1 = e1_blk;
5595                         if (e2_blk > lblk2)
5596                                 next2 = e1_blk;
5597                         /* Do we have something to swap */
5598                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5599                                 goto finish;
5600                         /* Move to the rightest boundary */
5601                         len = next1 - lblk1;
5602                         if (len < next2 - lblk2)
5603                                 len = next2 - lblk2;
5604                         if (len > count)
5605                                 len = count;
5606                         lblk1 += len;
5607                         lblk2 += len;
5608                         count -= len;
5609                         goto repeat;
5610                 }
5611
5612                 /* Prepare left boundary */
5613                 if (e1_blk < lblk1) {
5614                         split = 1;
5615                         *erp = ext4_force_split_extent_at(handle, inode1,
5616                                                 &path1, lblk1, 0);
5617                         if (unlikely(*erp))
5618                                 goto finish;
5619                 }
5620                 if (e2_blk < lblk2) {
5621                         split = 1;
5622                         *erp = ext4_force_split_extent_at(handle, inode2,
5623                                                 &path2,  lblk2, 0);
5624                         if (unlikely(*erp))
5625                                 goto finish;
5626                 }
5627                 /* ext4_split_extent_at() may result in leaf extent split,
5628                  * path must to be revalidated. */
5629                 if (split)
5630                         goto repeat;
5631
5632                 /* Prepare right boundary */
5633                 len = count;
5634                 if (len > e1_blk + e1_len - lblk1)
5635                         len = e1_blk + e1_len - lblk1;
5636                 if (len > e2_blk + e2_len - lblk2)
5637                         len = e2_blk + e2_len - lblk2;
5638
5639                 if (len != e1_len) {
5640                         split = 1;
5641                         *erp = ext4_force_split_extent_at(handle, inode1,
5642                                                 &path1, lblk1 + len, 0);
5643                         if (unlikely(*erp))
5644                                 goto finish;
5645                 }
5646                 if (len != e2_len) {
5647                         split = 1;
5648                         *erp = ext4_force_split_extent_at(handle, inode2,
5649                                                 &path2, lblk2 + len, 0);
5650                         if (*erp)
5651                                 goto finish;
5652                 }
5653                 /* ext4_split_extent_at() may result in leaf extent split,
5654                  * path must to be revalidated. */
5655                 if (split)
5656                         goto repeat;
5657
5658                 BUG_ON(e2_len != e1_len);
5659                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5660                 if (unlikely(*erp))
5661                         goto finish;
5662                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5663                 if (unlikely(*erp))
5664                         goto finish;
5665
5666                 /* Both extents are fully inside boundaries. Swap it now */
5667                 tmp_ex = *ex1;
5668                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5669                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5670                 ex1->ee_len = cpu_to_le16(e2_len);
5671                 ex2->ee_len = cpu_to_le16(e1_len);
5672                 if (unwritten)
5673                         ext4_ext_mark_unwritten(ex2);
5674                 if (ext4_ext_is_unwritten(&tmp_ex))
5675                         ext4_ext_mark_unwritten(ex1);
5676
5677                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5678                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5679                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5680                                       path2->p_depth);
5681                 if (unlikely(*erp))
5682                         goto finish;
5683                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5684                                       path1->p_depth);
5685                 /*
5686                  * Looks scarry ah..? second inode already points to new blocks,
5687                  * and it was successfully dirtied. But luckily error may happen
5688                  * only due to journal error, so full transaction will be
5689                  * aborted anyway.
5690                  */
5691                 if (unlikely(*erp))
5692                         goto finish;
5693                 lblk1 += len;
5694                 lblk2 += len;
5695                 replaced_count += len;
5696                 count -= len;
5697
5698         repeat:
5699                 if (path1) {
5700                         ext4_ext_drop_refs(path1);
5701                         kfree(path1);
5702                         path1 = NULL;
5703                 }
5704                 if (path2) {
5705                         ext4_ext_drop_refs(path2);
5706                         kfree(path2);
5707                         path2 = NULL;
5708                 }
5709         }
5710         return replaced_count;
5711 }