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 *path,
 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 *path,
 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         if (path->p_bh) {
 165                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 166                 /* path points to block */
 167                 err = __ext4_handle_dirty_metadata(where, line, handle,
 168                                                    inode, path->p_bh);
 169         } else {
 170                 /* path points to leaf/index in inode body */
 171                 err = ext4_mark_inode_dirty(handle, inode);
 172         }
 173         return err;
 174 }
 175
 176 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 177                               struct ext4_ext_path *path,
 178                               ext4_lblk_t block)
 179 {
 180         if (path) {
 181                 int depth = path->p_depth;
 182                 struct ext4_extent *ex;
 183
 184                 /*
 185                  * Try to predict block placement assuming that we are
 186                  * filling in a file which will eventually be
 187                  * non-sparse --- i.e., in the case of libbfd writing
 188                  * an ELF object sections out-of-order but in a way
 189                  * the eventually results in a contiguous object or
 190                  * executable file, or some database extending a table
 191                  * space file.  However, this is actually somewhat
 192                  * non-ideal if we are writing a sparse file such as
 193                  * qemu or KVM writing a raw image file that is going
 194                  * to stay fairly sparse, since it will end up
 195                  * fragmenting the file system's free space.  Maybe we
 196                  * should have some hueristics or some way to allow
 197                  * userspace to pass a hint to file system,
 198                  * especially if the latter case turns out to be
 199                  * common.
 200                  */
 201                 ex = path[depth].p_ext;
 202                 if (ex) {
 203                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 204                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 205
 206                         if (block > ext_block)
 207                                 return ext_pblk + (block - ext_block);
 208                         else
 209                                 return ext_pblk - (ext_block - block);
 210                 }
 211
 212                 /* it looks like index is empty;
 213                  * try to find starting block from index itself */
 214                 if (path[depth].p_bh)
 215                         return path[depth].p_bh->b_blocknr;
 216         }
 217
 218         /* OK. use inode's group */
 219         return ext4_inode_to_goal_block(inode);
 220 }
 221
 222 /*
 223  * Allocation for a meta data block
 224  */
 225 static ext4_fsblk_t
 226 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 227                         struct ext4_ext_path *path,
 228                         struct ext4_extent *ex, int *err, unsigned int flags)
 229 {
 230         ext4_fsblk_t goal, newblock;
 231
 232         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 233         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 234                                         NULL, err);
 235         return newblock;
 236 }
 237
 238 static inline int ext4_ext_space_block(struct inode *inode, int check)
 239 {
 240         int size;
 241
 242         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 243                         / sizeof(struct ext4_extent);
 244 #ifdef AGGRESSIVE_TEST
 245         if (!check && size > 6)
 246                 size = 6;
 247 #endif
 248         return size;
 249 }
 250
 251 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 252 {
 253         int size;
 254
 255         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 256                         / sizeof(struct ext4_extent_idx);
 257 #ifdef AGGRESSIVE_TEST
 258         if (!check && size > 5)
 259                 size = 5;
 260 #endif
 261         return size;
 262 }
 263
 264 static inline int ext4_ext_space_root(struct inode *inode, int check)
 265 {
 266         int size;
 267
 268         size = sizeof(EXT4_I(inode)->i_data);
 269         size -= sizeof(struct ext4_extent_header);
 270         size /= sizeof(struct ext4_extent);
 271 #ifdef AGGRESSIVE_TEST
 272         if (!check && size > 3)
 273                 size = 3;
 274 #endif
 275         return size;
 276 }
 277
 278 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 279 {
 280         int size;
 281
 282         size = sizeof(EXT4_I(inode)->i_data);
 283         size -= sizeof(struct ext4_extent_header);
 284         size /= sizeof(struct ext4_extent_idx);
 285 #ifdef AGGRESSIVE_TEST
 286         if (!check && size > 4)
 287                 size = 4;
 288 #endif
 289         return size;
 290 }
 291
 292 /*
 293  * Calculate the number of metadata blocks needed
 294  * to allocate @blocks
 295  * Worse case is one block per extent
 296  */
 297 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 298 {
 299         struct ext4_inode_info *ei = EXT4_I(inode);
 300         int idxs;
 301
 302         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 303                 / sizeof(struct ext4_extent_idx));
 304
 305         /*
 306          * If the new delayed allocation block is contiguous with the
 307          * previous da block, it can share index blocks with the
 308          * previous block, so we only need to allocate a new index
 309          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 310          * an additional index block, and at ldxs**3 blocks, yet
 311          * another index blocks.
 312          */
 313         if (ei->i_da_metadata_calc_len &&
 314             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 315                 int num = 0;
 316
 317                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 318                         num++;
 319                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 320                         num++;
 321                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 322                         num++;
 323                         ei->i_da_metadata_calc_len = 0;
 324                 } else
 325                         ei->i_da_metadata_calc_len++;
 326                 ei->i_da_metadata_calc_last_lblock++;
 327                 return num;
 328         }
 329
 330         /*
 331          * In the worst case we need a new set of index blocks at
 332          * every level of the inode's extent tree.
 333          */
 334         ei->i_da_metadata_calc_len = 1;
 335         ei->i_da_metadata_calc_last_lblock = lblock;
 336         return ext_depth(inode) + 1;
 337 }
 338
 339 static int
 340 ext4_ext_max_entries(struct inode *inode, int depth)
 341 {
 342         int max;
 343
 344         if (depth == ext_depth(inode)) {
 345                 if (depth == 0)
 346                         max = ext4_ext_space_root(inode, 1);
 347                 else
 348                         max = ext4_ext_space_root_idx(inode, 1);
 349         } else {
 350                 if (depth == 0)
 351                         max = ext4_ext_space_block(inode, 1);
 352                 else
 353                         max = ext4_ext_space_block_idx(inode, 1);
 354         }
 355
 356         return max;
 357 }
 358
 359 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 360 {
 361         ext4_fsblk_t block = ext4_ext_pblock(ext);
 362         int len = ext4_ext_get_actual_len(ext);
 363         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 364         ext4_lblk_t last = lblock + len - 1;
 365
 366         if (lblock > last)
 367                 return 0;
 368         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 369 }
 370
 371 static int ext4_valid_extent_idx(struct inode *inode,
 372                                 struct ext4_extent_idx *ext_idx)
 373 {
 374         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 375
 376         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 377 }
 378
 379 static int ext4_valid_extent_entries(struct inode *inode,
 380                                 struct ext4_extent_header *eh,
 381                                 int depth)
 382 {
 383         unsigned short entries;
 384         if (eh->eh_entries == 0)
 385                 return 1;
 386
 387         entries = le16_to_cpu(eh->eh_entries);
 388
 389         if (depth == 0) {
 390                 /* leaf entries */
 391                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 392                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 393                 ext4_fsblk_t pblock = 0;
 394                 ext4_lblk_t lblock = 0;
 395                 ext4_lblk_t prev = 0;
 396                 int len = 0;
 397                 while (entries) {
 398                         if (!ext4_valid_extent(inode, ext))
 399                                 return 0;
 400
 401                         /* Check for overlapping extents */
 402                         lblock = le32_to_cpu(ext->ee_block);
 403                         len = ext4_ext_get_actual_len(ext);
 404                         if ((lblock <= prev) && prev) {
 405                                 pblock = ext4_ext_pblock(ext);
 406                                 es->s_last_error_block = cpu_to_le64(pblock);
 407                                 return 0;
 408                         }
 409                         ext++;
 410                         entries--;
 411                         prev = lblock + len - 1;
 412                 }
 413         } else {
 414                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 415                 while (entries) {
 416                         if (!ext4_valid_extent_idx(inode, ext_idx))
 417                                 return 0;
 418                         ext_idx++;
 419                         entries--;
 420                 }
 421         }
 422         return 1;
 423 }
 424
 425 static int __ext4_ext_check(const char *function, unsigned int line,
 426                             struct inode *inode, struct ext4_extent_header *eh,
 427                             int depth, ext4_fsblk_t pblk)
 428 {
 429         const char *error_msg;
 430         int max = 0;
 431
 432         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 433                 error_msg = "invalid magic";
 434                 goto corrupted;
 435         }
 436         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 437                 error_msg = "unexpected eh_depth";
 438                 goto corrupted;
 439         }
 440         if (unlikely(eh->eh_max == 0)) {
 441                 error_msg = "invalid eh_max";
 442                 goto corrupted;
 443         }
 444         max = ext4_ext_max_entries(inode, depth);
 445         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 446                 error_msg = "too large eh_max";
 447                 goto corrupted;
 448         }
 449         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 450                 error_msg = "invalid eh_entries";
 451                 goto corrupted;
 452         }
 453         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 454                 error_msg = "invalid extent entries";
 455                 goto corrupted;
 456         }
 457         /* Verify checksum on non-root extent tree nodes */
 458         if (ext_depth(inode) != depth &&
 459             !ext4_extent_block_csum_verify(inode, eh)) {
 460                 error_msg = "extent tree corrupted";
 461                 goto corrupted;
 462         }
 463         return 0;
 464
 465 corrupted:
 466         ext4_error_inode(inode, function, line, 0,
 467                          "pblk %llu bad header/extent: %s - magic %x, "
 468                          "entries %u, max %u(%u), depth %u(%u)",
 469                          (unsigned long long) pblk, error_msg,
 470                          le16_to_cpu(eh->eh_magic),
 471                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 472                          max, le16_to_cpu(eh->eh_depth), depth);
 473         return -EIO;
 474 }
 475
 476 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 477         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 478
 479 int ext4_ext_check_inode(struct inode *inode)
 480 {
 481         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 482 }
 483
 484 static struct buffer_head *
 485 __read_extent_tree_block(const char *function, unsigned int line,
 486                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 487                          int flags)
 488 {
 489         struct buffer_head              *bh;
 490         int                             err;
 491
 492         bh = sb_getblk(inode->i_sb, pblk);
 493         if (unlikely(!bh))
 494                 return ERR_PTR(-ENOMEM);
 495
 496         if (!bh_uptodate_or_lock(bh)) {
 497                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 498                 err = bh_submit_read(bh);
 499                 if (err < 0)
 500                         goto errout;
 501         }
 502         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 503                 return bh;
 504         err = __ext4_ext_check(function, line, inode,
 505                                ext_block_hdr(bh), depth, pblk);
 506         if (err)
 507                 goto errout;
 508         set_buffer_verified(bh);
 509         /*
 510          * If this is a leaf block, cache all of its entries
 511          */
 512         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 513                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 514                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 515                 ext4_lblk_t prev = 0;
 516                 int i;
 517
 518                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 519                         unsigned int status = EXTENT_STATUS_WRITTEN;
 520                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 521                         int len = ext4_ext_get_actual_len(ex);
 522
 523                         if (prev && (prev != lblk))
 524                                 ext4_es_cache_extent(inode, prev,
 525                                                      lblk - prev, ~0,
 526                                                      EXTENT_STATUS_HOLE);
 527
 528                         if (ext4_ext_is_unwritten(ex))
 529                                 status = EXTENT_STATUS_UNWRITTEN;
 530                         ext4_es_cache_extent(inode, lblk, len,
 531                                              ext4_ext_pblock(ex), status);
 532                         prev = lblk + len;
 533                 }
 534         }
 535         return bh;
 536 errout:
 537         put_bh(bh);
 538         return ERR_PTR(err);
 539
 540 }
 541
 542 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 543         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 544                                  (depth), (flags))
 545
 546 /*
 547  * This function is called to cache a file's extent information in the
 548  * extent status tree
 549  */
 550 int ext4_ext_precache(struct inode *inode)
 551 {
 552         struct ext4_inode_info *ei = EXT4_I(inode);
 553         struct ext4_ext_path *path = NULL;
 554         struct buffer_head *bh;
 555         int i = 0, depth, ret = 0;
 556
 557         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 558                 return 0;       /* not an extent-mapped inode */
 559
 560         down_read(&ei->i_data_sem);
 561         depth = ext_depth(inode);
 562
 563         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 564                        GFP_NOFS);
 565         if (path == NULL) {
 566                 up_read(&ei->i_data_sem);
 567                 return -ENOMEM;
 568         }
 569
 570         /* Don't cache anything if there are no external extent blocks */
 571         if (depth == 0)
 572                 goto out;
 573         path[0].p_hdr = ext_inode_hdr(inode);
 574         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 575         if (ret)
 576                 goto out;
 577         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 578         while (i >= 0) {
 579                 /*
 580                  * If this is a leaf block or we've reached the end of
 581                  * the index block, go up
 582                  */
 583                 if ((i == depth) ||
 584                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 585                         brelse(path[i].p_bh);
 586                         path[i].p_bh = NULL;
 587                         i--;
 588                         continue;
 589                 }
 590                 bh = read_extent_tree_block(inode,
 591                                             ext4_idx_pblock(path[i].p_idx++),
 592                                             depth - i - 1,
 593                                             EXT4_EX_FORCE_CACHE);
 594                 if (IS_ERR(bh)) {
 595                         ret = PTR_ERR(bh);
 596                         break;
 597                 }
 598                 i++;
 599                 path[i].p_bh = bh;
 600                 path[i].p_hdr = ext_block_hdr(bh);
 601                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 602         }
 603         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 604 out:
 605         up_read(&ei->i_data_sem);
 606         ext4_ext_drop_refs(path);
 607         kfree(path);
 608         return ret;
 609 }
 610
 611 #ifdef EXT_DEBUG
 612 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 613 {
 614         int k, l = path->p_depth;
 615
 616         ext_debug("path:");
 617         for (k = 0; k <= l; k++, path++) {
 618                 if (path->p_idx) {
 619                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 620                             ext4_idx_pblock(path->p_idx));
 621                 } else if (path->p_ext) {
 622                         ext_debug("  %d:[%d]%d:%llu ",
 623                                   le32_to_cpu(path->p_ext->ee_block),
 624                                   ext4_ext_is_unwritten(path->p_ext),
 625                                   ext4_ext_get_actual_len(path->p_ext),
 626                                   ext4_ext_pblock(path->p_ext));
 627                 } else
 628                         ext_debug("  []");
 629         }
 630         ext_debug("\n");
 631 }
 632
 633 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 634 {
 635         int depth = ext_depth(inode);
 636         struct ext4_extent_header *eh;
 637         struct ext4_extent *ex;
 638         int i;
 639
 640         if (!path)
 641                 return;
 642
 643         eh = path[depth].p_hdr;
 644         ex = EXT_FIRST_EXTENT(eh);
 645
 646         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 647
 648         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 649                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 650                           ext4_ext_is_unwritten(ex),
 651                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 652         }
 653         ext_debug("\n");
 654 }
 655
 656 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 657                         ext4_fsblk_t newblock, int level)
 658 {
 659         int depth = ext_depth(inode);
 660         struct ext4_extent *ex;
 661
 662         if (depth != level) {
 663                 struct ext4_extent_idx *idx;
 664                 idx = path[level].p_idx;
 665                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 666                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 667                                         le32_to_cpu(idx->ei_block),
 668                                         ext4_idx_pblock(idx),
 669                                         newblock);
 670                         idx++;
 671                 }
 672
 673                 return;
 674         }
 675
 676         ex = path[depth].p_ext;
 677         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 678                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 679                                 le32_to_cpu(ex->ee_block),
 680                                 ext4_ext_pblock(ex),
 681                                 ext4_ext_is_unwritten(ex),
 682                                 ext4_ext_get_actual_len(ex),
 683                                 newblock);
 684                 ex++;
 685         }
 686 }
 687
 688 #else
 689 #define ext4_ext_show_path(inode, path)
 690 #define ext4_ext_show_leaf(inode, path)
 691 #define ext4_ext_show_move(inode, path, newblock, level)
 692 #endif
 693
 694 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 695 {
 696         int depth = path->p_depth;
 697         int i;
 698
 699         for (i = 0; i <= depth; i++, path++)
 700                 if (path->p_bh) {
 701                         brelse(path->p_bh);
 702                         path->p_bh = NULL;
 703                 }
 704 }
 705
 706 /*
 707  * ext4_ext_binsearch_idx:
 708  * binary search for the closest index of the given block
 709  * the header must be checked before calling this
 710  */
 711 static void
 712 ext4_ext_binsearch_idx(struct inode *inode,
 713                         struct ext4_ext_path *path, ext4_lblk_t block)
 714 {
 715         struct ext4_extent_header *eh = path->p_hdr;
 716         struct ext4_extent_idx *r, *l, *m;
 717
 718
 719         ext_debug("binsearch for %u(idx):  ", block);
 720
 721         l = EXT_FIRST_INDEX(eh) + 1;
 722         r = EXT_LAST_INDEX(eh);
 723         while (l <= r) {
 724                 m = l + (r - l) / 2;
 725                 if (block < le32_to_cpu(m->ei_block))
 726                         r = m - 1;
 727                 else
 728                         l = m + 1;
 729                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 730                                 m, le32_to_cpu(m->ei_block),
 731                                 r, le32_to_cpu(r->ei_block));
 732         }
 733
 734         path->p_idx = l - 1;
 735         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 736                   ext4_idx_pblock(path->p_idx));
 737
 738 #ifdef CHECK_BINSEARCH
 739         {
 740                 struct ext4_extent_idx *chix, *ix;
 741                 int k;
 742
 743                 chix = ix = EXT_FIRST_INDEX(eh);
 744                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 745                   if (k != 0 &&
 746                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 747                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 748                                        "first=0x%p\n", k,
 749                                        ix, EXT_FIRST_INDEX(eh));
 750                                 printk(KERN_DEBUG "%u <= %u\n",
 751                                        le32_to_cpu(ix->ei_block),
 752                                        le32_to_cpu(ix[-1].ei_block));
 753                         }
 754                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 755                                            <= le32_to_cpu(ix[-1].ei_block));
 756                         if (block < le32_to_cpu(ix->ei_block))
 757                                 break;
 758                         chix = ix;
 759                 }
 760                 BUG_ON(chix != path->p_idx);
 761         }
 762 #endif
 763
 764 }
 765
 766 /*
 767  * ext4_ext_binsearch:
 768  * binary search for closest extent of the given block
 769  * the header must be checked before calling this
 770  */
 771 static void
 772 ext4_ext_binsearch(struct inode *inode,
 773                 struct ext4_ext_path *path, ext4_lblk_t block)
 774 {
 775         struct ext4_extent_header *eh = path->p_hdr;
 776         struct ext4_extent *r, *l, *m;
 777
 778         if (eh->eh_entries == 0) {
 779                 /*
 780                  * this leaf is empty:
 781                  * we get such a leaf in split/add case
 782                  */
 783                 return;
 784         }
 785
 786         ext_debug("binsearch for %u:  ", block);
 787
 788         l = EXT_FIRST_EXTENT(eh) + 1;
 789         r = EXT_LAST_EXTENT(eh);
 790
 791         while (l <= r) {
 792                 m = l + (r - l) / 2;
 793                 if (block < le32_to_cpu(m->ee_block))
 794                         r = m - 1;
 795                 else
 796                         l = m + 1;
 797                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 798                                 m, le32_to_cpu(m->ee_block),
 799                                 r, le32_to_cpu(r->ee_block));
 800         }
 801
 802         path->p_ext = l - 1;
 803         ext_debug("  -> %d:%llu:[%d]%d ",
 804                         le32_to_cpu(path->p_ext->ee_block),
 805                         ext4_ext_pblock(path->p_ext),
 806                         ext4_ext_is_unwritten(path->p_ext),
 807                         ext4_ext_get_actual_len(path->p_ext));
 808
 809 #ifdef CHECK_BINSEARCH
 810         {
 811                 struct ext4_extent *chex, *ex;
 812                 int k;
 813
 814                 chex = ex = EXT_FIRST_EXTENT(eh);
 815                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 816                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 817                                           <= le32_to_cpu(ex[-1].ee_block));
 818                         if (block < le32_to_cpu(ex->ee_block))
 819                                 break;
 820                         chex = ex;
 821                 }
 822                 BUG_ON(chex != path->p_ext);
 823         }
 824 #endif
 825
 826 }
 827
 828 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 829 {
 830         struct ext4_extent_header *eh;
 831
 832         eh = ext_inode_hdr(inode);
 833         eh->eh_depth = 0;
 834         eh->eh_entries = 0;
 835         eh->eh_magic = EXT4_EXT_MAGIC;
 836         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 837         ext4_mark_inode_dirty(handle, inode);
 838         return 0;
 839 }
 840
 841 struct ext4_ext_path *
 842 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 843                      struct ext4_ext_path *path, int flags)
 844 {
 845         struct ext4_extent_header *eh;
 846         struct buffer_head *bh;
 847         short int depth, i, ppos = 0, alloc = 0;
 848         int ret;
 849
 850         eh = ext_inode_hdr(inode);
 851         depth = ext_depth(inode);
 852
 853         /* account possible depth increase */
 854         if (!path) {
 855                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 856                                 GFP_NOFS);
 857                 if (!path)
 858                         return ERR_PTR(-ENOMEM);
 859                 alloc = 1;
 860         }
 861         path[0].p_hdr = eh;
 862         path[0].p_bh = NULL;
 863
 864         i = depth;
 865         /* walk through the tree */
 866         while (i) {
 867                 ext_debug("depth %d: num %d, max %d\n",
 868                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 869
 870                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 871                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 872                 path[ppos].p_depth = i;
 873                 path[ppos].p_ext = NULL;
 874
 875                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 876                                             flags);
 877                 if (IS_ERR(bh)) {
 878                         ret = PTR_ERR(bh);
 879                         goto err;
 880                 }
 881
 882                 eh = ext_block_hdr(bh);
 883                 ppos++;
 884                 if (unlikely(ppos > depth)) {
 885                         put_bh(bh);
 886                         EXT4_ERROR_INODE(inode,
 887                                          "ppos %d > depth %d", ppos, depth);
 888                         ret = -EIO;
 889                         goto err;
 890                 }
 891                 path[ppos].p_bh = bh;
 892                 path[ppos].p_hdr = eh;
 893         }
 894
 895         path[ppos].p_depth = i;
 896         path[ppos].p_ext = NULL;
 897         path[ppos].p_idx = NULL;
 898
 899         /* find extent */
 900         ext4_ext_binsearch(inode, path + ppos, block);
 901         /* if not an empty leaf */
 902         if (path[ppos].p_ext)
 903                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 904
 905         ext4_ext_show_path(inode, path);
 906
 907         return path;
 908
 909 err:
 910         ext4_ext_drop_refs(path);
 911         if (alloc)
 912                 kfree(path);
 913         return ERR_PTR(ret);
 914 }
 915
 916 /*
 917  * ext4_ext_insert_index:
 918  * insert new index [@logical;@ptr] into the block at @curp;
 919  * check where to insert: before @curp or after @curp
 920  */
 921 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 922                                  struct ext4_ext_path *curp,
 923                                  int logical, ext4_fsblk_t ptr)
 924 {
 925         struct ext4_extent_idx *ix;
 926         int len, err;
 927
 928         err = ext4_ext_get_access(handle, inode, curp);
 929         if (err)
 930                 return err;
 931
 932         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 933                 EXT4_ERROR_INODE(inode,
 934                                  "logical %d == ei_block %d!",
 935                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 936                 return -EIO;
 937         }
 938
 939         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 940                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 941                 EXT4_ERROR_INODE(inode,
 942                                  "eh_entries %d >= eh_max %d!",
 943                                  le16_to_cpu(curp->p_hdr->eh_entries),
 944                                  le16_to_cpu(curp->p_hdr->eh_max));
 945                 return -EIO;
 946         }
 947
 948         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 949                 /* insert after */
 950                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 951                 ix = curp->p_idx + 1;
 952         } else {
 953                 /* insert before */
 954                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 955                 ix = curp->p_idx;
 956         }
 957
 958         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 959         BUG_ON(len < 0);
 960         if (len > 0) {
 961                 ext_debug("insert new index %d: "
 962                                 "move %d indices from 0x%p to 0x%p\n",
 963                                 logical, len, ix, ix + 1);
 964                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 965         }
 966
 967         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 968                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 969                 return -EIO;
 970         }
 971
 972         ix->ei_block = cpu_to_le32(logical);
 973         ext4_idx_store_pblock(ix, ptr);
 974         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 975
 976         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 977                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 978                 return -EIO;
 979         }
 980
 981         err = ext4_ext_dirty(handle, inode, curp);
 982         ext4_std_error(inode->i_sb, err);
 983
 984         return err;
 985 }
 986
 987 /*
 988  * ext4_ext_split:
 989  * inserts new subtree into the path, using free index entry
 990  * at depth @at:
 991  * - allocates all needed blocks (new leaf and all intermediate index blocks)
 992  * - makes decision where to split
 993  * - moves remaining extents and index entries (right to the split point)
 994  *   into the newly allocated blocks
 995  * - initializes subtree
 996  */
 997 static int ext4_ext_split(handle_t *handle, struct inode *inode,
 998                           unsigned int flags,
 999                           struct ext4_ext_path *path,
1000                           struct ext4_extent *newext, int at)
1001 {
1002         struct buffer_head *bh = NULL;
1003         int depth = ext_depth(inode);
1004         struct ext4_extent_header *neh;
1005         struct ext4_extent_idx *fidx;
1006         int i = at, k, m, a;
1007         ext4_fsblk_t newblock, oldblock;
1008         __le32 border;
1009         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1010         int err = 0;
1011
1012         /* make decision: where to split? */
1013         /* FIXME: now decision is simplest: at current extent */
1014
1015         /* if current leaf will be split, then we should use
1016          * border from split point */
1017         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1018                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1019                 return -EIO;
1020         }
1021         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1022                 border = path[depth].p_ext[1].ee_block;
1023                 ext_debug("leaf will be split."
1024                                 " next leaf starts at %d\n",
1025                                   le32_to_cpu(border));
1026         } else {
1027                 border = newext->ee_block;
1028                 ext_debug("leaf will be added."
1029                                 " next leaf starts at %d\n",
1030                                 le32_to_cpu(border));
1031         }
1032
1033         /*
1034          * If error occurs, then we break processing
1035          * and mark filesystem read-only. index won't
1036          * be inserted and tree will be in consistent
1037          * state. Next mount will repair buffers too.
1038          */
1039
1040         /*
1041          * Get array to track all allocated blocks.
1042          * We need this to handle errors and free blocks
1043          * upon them.
1044          */
1045         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1046         if (!ablocks)
1047                 return -ENOMEM;
1048
1049         /* allocate all needed blocks */
1050         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1051         for (a = 0; a < depth - at; a++) {
1052                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1053                                                    newext, &err, flags);
1054                 if (newblock == 0)
1055                         goto cleanup;
1056                 ablocks[a] = newblock;
1057         }
1058
1059         /* initialize new leaf */
1060         newblock = ablocks[--a];
1061         if (unlikely(newblock == 0)) {
1062                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1063                 err = -EIO;
1064                 goto cleanup;
1065         }
1066         bh = sb_getblk(inode->i_sb, newblock);
1067         if (unlikely(!bh)) {
1068                 err = -ENOMEM;
1069                 goto cleanup;
1070         }
1071         lock_buffer(bh);
1072
1073         err = ext4_journal_get_create_access(handle, bh);
1074         if (err)
1075                 goto cleanup;
1076
1077         neh = ext_block_hdr(bh);
1078         neh->eh_entries = 0;
1079         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1080         neh->eh_magic = EXT4_EXT_MAGIC;
1081         neh->eh_depth = 0;
1082
1083         /* move remainder of path[depth] to the new leaf */
1084         if (unlikely(path[depth].p_hdr->eh_entries !=
1085                      path[depth].p_hdr->eh_max)) {
1086                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1087                                  path[depth].p_hdr->eh_entries,
1088                                  path[depth].p_hdr->eh_max);
1089                 err = -EIO;
1090                 goto cleanup;
1091         }
1092         /* start copy from next extent */
1093         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1094         ext4_ext_show_move(inode, path, newblock, depth);
1095         if (m) {
1096                 struct ext4_extent *ex;
1097                 ex = EXT_FIRST_EXTENT(neh);
1098                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1099                 le16_add_cpu(&neh->eh_entries, m);
1100         }
1101
1102         ext4_extent_block_csum_set(inode, neh);
1103         set_buffer_uptodate(bh);
1104         unlock_buffer(bh);
1105
1106         err = ext4_handle_dirty_metadata(handle, inode, bh);
1107         if (err)
1108                 goto cleanup;
1109         brelse(bh);
1110         bh = NULL;
1111
1112         /* correct old leaf */
1113         if (m) {
1114                 err = ext4_ext_get_access(handle, inode, path + depth);
1115                 if (err)
1116                         goto cleanup;
1117                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1118                 err = ext4_ext_dirty(handle, inode, path + depth);
1119                 if (err)
1120                         goto cleanup;
1121
1122         }
1123
1124         /* create intermediate indexes */
1125         k = depth - at - 1;
1126         if (unlikely(k < 0)) {
1127                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1128                 err = -EIO;
1129                 goto cleanup;
1130         }
1131         if (k)
1132                 ext_debug("create %d intermediate indices\n", k);
1133         /* insert new index into current index block */
1134         /* current depth stored in i var */
1135         i = depth - 1;
1136         while (k--) {
1137                 oldblock = newblock;
1138                 newblock = ablocks[--a];
1139                 bh = sb_getblk(inode->i_sb, newblock);
1140                 if (unlikely(!bh)) {
1141                         err = -ENOMEM;
1142                         goto cleanup;
1143                 }
1144                 lock_buffer(bh);
1145
1146                 err = ext4_journal_get_create_access(handle, bh);
1147                 if (err)
1148                         goto cleanup;
1149
1150                 neh = ext_block_hdr(bh);
1151                 neh->eh_entries = cpu_to_le16(1);
1152                 neh->eh_magic = EXT4_EXT_MAGIC;
1153                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1154                 neh->eh_depth = cpu_to_le16(depth - i);
1155                 fidx = EXT_FIRST_INDEX(neh);
1156                 fidx->ei_block = border;
1157                 ext4_idx_store_pblock(fidx, oldblock);
1158
1159                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1160                                 i, newblock, le32_to_cpu(border), oldblock);
1161
1162                 /* move remainder of path[i] to the new index block */
1163                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1164                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1165                         EXT4_ERROR_INODE(inode,
1166                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1167                                          le32_to_cpu(path[i].p_ext->ee_block));
1168                         err = -EIO;
1169                         goto cleanup;
1170                 }
1171                 /* start copy indexes */
1172                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1173                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1174                                 EXT_MAX_INDEX(path[i].p_hdr));
1175                 ext4_ext_show_move(inode, path, newblock, i);
1176                 if (m) {
1177                         memmove(++fidx, path[i].p_idx,
1178                                 sizeof(struct ext4_extent_idx) * m);
1179                         le16_add_cpu(&neh->eh_entries, m);
1180                 }
1181                 ext4_extent_block_csum_set(inode, neh);
1182                 set_buffer_uptodate(bh);
1183                 unlock_buffer(bh);
1184
1185                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1186                 if (err)
1187                         goto cleanup;
1188                 brelse(bh);
1189                 bh = NULL;
1190
1191                 /* correct old index */
1192                 if (m) {
1193                         err = ext4_ext_get_access(handle, inode, path + i);
1194                         if (err)
1195                                 goto cleanup;
1196                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1197                         err = ext4_ext_dirty(handle, inode, path + i);
1198                         if (err)
1199                                 goto cleanup;
1200                 }
1201
1202                 i--;
1203         }
1204
1205         /* insert new index */
1206         err = ext4_ext_insert_index(handle, inode, path + at,
1207                                     le32_to_cpu(border), newblock);
1208
1209 cleanup:
1210         if (bh) {
1211                 if (buffer_locked(bh))
1212                         unlock_buffer(bh);
1213                 brelse(bh);
1214         }
1215
1216         if (err) {
1217                 /* free all allocated blocks in error case */
1218                 for (i = 0; i < depth; i++) {
1219                         if (!ablocks[i])
1220                                 continue;
1221                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1222                                          EXT4_FREE_BLOCKS_METADATA);
1223                 }
1224         }
1225         kfree(ablocks);
1226
1227         return err;
1228 }
1229
1230 /*
1231  * ext4_ext_grow_indepth:
1232  * implements tree growing procedure:
1233  * - allocates new block
1234  * - moves top-level data (index block or leaf) into the new block
1235  * - initializes new top-level, creating index that points to the
1236  *   just created block
1237  */
1238 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1239                                  unsigned int flags,
1240                                  struct ext4_extent *newext)
1241 {
1242         struct ext4_extent_header *neh;
1243         struct buffer_head *bh;
1244         ext4_fsblk_t newblock;
1245         int err = 0;
1246
1247         newblock = ext4_ext_new_meta_block(handle, inode, NULL,
1248                 newext, &err, flags);
1249         if (newblock == 0)
1250                 return err;
1251
1252         bh = sb_getblk(inode->i_sb, newblock);
1253         if (unlikely(!bh))
1254                 return -ENOMEM;
1255         lock_buffer(bh);
1256
1257         err = ext4_journal_get_create_access(handle, bh);
1258         if (err) {
1259                 unlock_buffer(bh);
1260                 goto out;
1261         }
1262
1263         /* move top-level index/leaf into new block */
1264         memmove(bh->b_data, EXT4_I(inode)->i_data,
1265                 sizeof(EXT4_I(inode)->i_data));
1266
1267         /* set size of new block */
1268         neh = ext_block_hdr(bh);
1269         /* old root could have indexes or leaves
1270          * so calculate e_max right way */
1271         if (ext_depth(inode))
1272                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1273         else
1274                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1275         neh->eh_magic = EXT4_EXT_MAGIC;
1276         ext4_extent_block_csum_set(inode, neh);
1277         set_buffer_uptodate(bh);
1278         unlock_buffer(bh);
1279
1280         err = ext4_handle_dirty_metadata(handle, inode, bh);
1281         if (err)
1282                 goto out;
1283
1284         /* Update top-level index: num,max,pointer */
1285         neh = ext_inode_hdr(inode);
1286         neh->eh_entries = cpu_to_le16(1);
1287         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1288         if (neh->eh_depth == 0) {
1289                 /* Root extent block becomes index block */
1290                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1291                 EXT_FIRST_INDEX(neh)->ei_block =
1292                         EXT_FIRST_EXTENT(neh)->ee_block;
1293         }
1294         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1295                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1296                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1297                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1298
1299         le16_add_cpu(&neh->eh_depth, 1);
1300         ext4_mark_inode_dirty(handle, inode);
1301 out:
1302         brelse(bh);
1303
1304         return err;
1305 }
1306
1307 /*
1308  * ext4_ext_create_new_leaf:
1309  * finds empty index and adds new leaf.
1310  * if no free index is found, then it requests in-depth growing.
1311  */
1312 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1313                                     unsigned int mb_flags,
1314                                     unsigned int gb_flags,
1315                                     struct ext4_ext_path *path,
1316                                     struct ext4_extent *newext)
1317 {
1318         struct ext4_ext_path *curp;
1319         int depth, i, err = 0;
1320
1321 repeat:
1322         i = depth = ext_depth(inode);
1323
1324         /* walk up to the tree and look for free index entry */
1325         curp = path + depth;
1326         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1327                 i--;
1328                 curp--;
1329         }
1330
1331         /* we use already allocated block for index block,
1332          * so subsequent data blocks should be contiguous */
1333         if (EXT_HAS_FREE_INDEX(curp)) {
1334                 /* if we found index with free entry, then use that
1335                  * entry: create all needed subtree and add new leaf */
1336                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1337                 if (err)
1338                         goto out;
1339
1340                 /* refill path */
1341                 ext4_ext_drop_refs(path);
1342                 path = ext4_ext_find_extent(inode,
1343                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1344                                     path, gb_flags);
1345                 if (IS_ERR(path))
1346                         err = PTR_ERR(path);
1347         } else {
1348                 /* tree is full, time to grow in depth */
1349                 err = ext4_ext_grow_indepth(handle, inode, mb_flags, newext);
1350                 if (err)
1351                         goto out;
1352
1353                 /* refill path */
1354                 ext4_ext_drop_refs(path);
1355                 path = ext4_ext_find_extent(inode,
1356                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1357                                     path, gb_flags);
1358                 if (IS_ERR(path)) {
1359                         err = PTR_ERR(path);
1360                         goto out;
1361                 }
1362
1363                 /*
1364                  * only first (depth 0 -> 1) produces free space;
1365                  * in all other cases we have to split the grown tree
1366                  */
1367                 depth = ext_depth(inode);
1368                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1369                         /* now we need to split */
1370                         goto repeat;
1371                 }
1372         }
1373
1374 out:
1375         return err;
1376 }
1377
1378 /*
1379  * search the closest allocated block to the left for *logical
1380  * and returns it at @logical + it's physical address at @phys
1381  * if *logical is the smallest allocated block, the function
1382  * returns 0 at @phys
1383  * return value contains 0 (success) or error code
1384  */
1385 static int ext4_ext_search_left(struct inode *inode,
1386                                 struct ext4_ext_path *path,
1387                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1388 {
1389         struct ext4_extent_idx *ix;
1390         struct ext4_extent *ex;
1391         int depth, ee_len;
1392
1393         if (unlikely(path == NULL)) {
1394                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1395                 return -EIO;
1396         }
1397         depth = path->p_depth;
1398         *phys = 0;
1399
1400         if (depth == 0 && path->p_ext == NULL)
1401                 return 0;
1402
1403         /* usually extent in the path covers blocks smaller
1404          * then *logical, but it can be that extent is the
1405          * first one in the file */
1406
1407         ex = path[depth].p_ext;
1408         ee_len = ext4_ext_get_actual_len(ex);
1409         if (*logical < le32_to_cpu(ex->ee_block)) {
1410                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1411                         EXT4_ERROR_INODE(inode,
1412                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1413                                          *logical, le32_to_cpu(ex->ee_block));
1414                         return -EIO;
1415                 }
1416                 while (--depth >= 0) {
1417                         ix = path[depth].p_idx;
1418                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1419                                 EXT4_ERROR_INODE(inode,
1420                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1421                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1422                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1423                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1424                                   depth);
1425                                 return -EIO;
1426                         }
1427                 }
1428                 return 0;
1429         }
1430
1431         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1432                 EXT4_ERROR_INODE(inode,
1433                                  "logical %d < ee_block %d + ee_len %d!",
1434                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1435                 return -EIO;
1436         }
1437
1438         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1439         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1440         return 0;
1441 }
1442
1443 /*
1444  * search the closest allocated block to the right for *logical
1445  * and returns it at @logical + it's physical address at @phys
1446  * if *logical is the largest allocated block, the function
1447  * returns 0 at @phys
1448  * return value contains 0 (success) or error code
1449  */
1450 static int ext4_ext_search_right(struct inode *inode,
1451                                  struct ext4_ext_path *path,
1452                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1453                                  struct ext4_extent **ret_ex)
1454 {
1455         struct buffer_head *bh = NULL;
1456         struct ext4_extent_header *eh;
1457         struct ext4_extent_idx *ix;
1458         struct ext4_extent *ex;
1459         ext4_fsblk_t block;
1460         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1461         int ee_len;
1462
1463         if (unlikely(path == NULL)) {
1464                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1465                 return -EIO;
1466         }
1467         depth = path->p_depth;
1468         *phys = 0;
1469
1470         if (depth == 0 && path->p_ext == NULL)
1471                 return 0;
1472
1473         /* usually extent in the path covers blocks smaller
1474          * then *logical, but it can be that extent is the
1475          * first one in the file */
1476
1477         ex = path[depth].p_ext;
1478         ee_len = ext4_ext_get_actual_len(ex);
1479         if (*logical < le32_to_cpu(ex->ee_block)) {
1480                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1481                         EXT4_ERROR_INODE(inode,
1482                                          "first_extent(path[%d].p_hdr) != ex",
1483                                          depth);
1484                         return -EIO;
1485                 }
1486                 while (--depth >= 0) {
1487                         ix = path[depth].p_idx;
1488                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1489                                 EXT4_ERROR_INODE(inode,
1490                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1491                                                  *logical);
1492                                 return -EIO;
1493                         }
1494                 }
1495                 goto found_extent;
1496         }
1497
1498         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1499                 EXT4_ERROR_INODE(inode,
1500                                  "logical %d < ee_block %d + ee_len %d!",
1501                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1502                 return -EIO;
1503         }
1504
1505         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1506                 /* next allocated block in this leaf */
1507                 ex++;
1508                 goto found_extent;
1509         }
1510
1511         /* go up and search for index to the right */
1512         while (--depth >= 0) {
1513                 ix = path[depth].p_idx;
1514                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1515                         goto got_index;
1516         }
1517
1518         /* we've gone up to the root and found no index to the right */
1519         return 0;
1520
1521 got_index:
1522         /* we've found index to the right, let's
1523          * follow it and find the closest allocated
1524          * block to the right */
1525         ix++;
1526         block = ext4_idx_pblock(ix);
1527         while (++depth < path->p_depth) {
1528                 /* subtract from p_depth to get proper eh_depth */
1529                 bh = read_extent_tree_block(inode, block,
1530                                             path->p_depth - depth, 0);
1531                 if (IS_ERR(bh))
1532                         return PTR_ERR(bh);
1533                 eh = ext_block_hdr(bh);
1534                 ix = EXT_FIRST_INDEX(eh);
1535                 block = ext4_idx_pblock(ix);
1536                 put_bh(bh);
1537         }
1538
1539         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1540         if (IS_ERR(bh))
1541                 return PTR_ERR(bh);
1542         eh = ext_block_hdr(bh);
1543         ex = EXT_FIRST_EXTENT(eh);
1544 found_extent:
1545         *logical = le32_to_cpu(ex->ee_block);
1546         *phys = ext4_ext_pblock(ex);
1547         *ret_ex = ex;
1548         if (bh)
1549                 put_bh(bh);
1550         return 0;
1551 }
1552
1553 /*
1554  * ext4_ext_next_allocated_block:
1555  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1556  * NOTE: it considers block number from index entry as
1557  * allocated block. Thus, index entries have to be consistent
1558  * with leaves.
1559  */
1560 static ext4_lblk_t
1561 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1562 {
1563         int depth;
1564
1565         BUG_ON(path == NULL);
1566         depth = path->p_depth;
1567
1568         if (depth == 0 && path->p_ext == NULL)
1569                 return EXT_MAX_BLOCKS;
1570
1571         while (depth >= 0) {
1572                 if (depth == path->p_depth) {
1573                         /* leaf */
1574                         if (path[depth].p_ext &&
1575                                 path[depth].p_ext !=
1576                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1577                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1578                 } else {
1579                         /* index */
1580                         if (path[depth].p_idx !=
1581                                         EXT_LAST_INDEX(path[depth].p_hdr))
1582                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1583                 }
1584                 depth--;
1585         }
1586
1587         return EXT_MAX_BLOCKS;
1588 }
1589
1590 /*
1591  * ext4_ext_next_leaf_block:
1592  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1593  */
1594 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1595 {
1596         int depth;
1597
1598         BUG_ON(path == NULL);
1599         depth = path->p_depth;
1600
1601         /* zero-tree has no leaf blocks at all */
1602         if (depth == 0)
1603                 return EXT_MAX_BLOCKS;
1604
1605         /* go to index block */
1606         depth--;
1607
1608         while (depth >= 0) {
1609                 if (path[depth].p_idx !=
1610                                 EXT_LAST_INDEX(path[depth].p_hdr))
1611                         return (ext4_lblk_t)
1612                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1613                 depth--;
1614         }
1615
1616         return EXT_MAX_BLOCKS;
1617 }
1618
1619 /*
1620  * ext4_ext_correct_indexes:
1621  * if leaf gets modified and modified extent is first in the leaf,
1622  * then we have to correct all indexes above.
1623  * TODO: do we need to correct tree in all cases?
1624  */
1625 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1626                                 struct ext4_ext_path *path)
1627 {
1628         struct ext4_extent_header *eh;
1629         int depth = ext_depth(inode);
1630         struct ext4_extent *ex;
1631         __le32 border;
1632         int k, err = 0;
1633
1634         eh = path[depth].p_hdr;
1635         ex = path[depth].p_ext;
1636
1637         if (unlikely(ex == NULL || eh == NULL)) {
1638                 EXT4_ERROR_INODE(inode,
1639                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1640                 return -EIO;
1641         }
1642
1643         if (depth == 0) {
1644                 /* there is no tree at all */
1645                 return 0;
1646         }
1647
1648         if (ex != EXT_FIRST_EXTENT(eh)) {
1649                 /* we correct tree if first leaf got modified only */
1650                 return 0;
1651         }
1652
1653         /*
1654          * TODO: we need correction if border is smaller than current one
1655          */
1656         k = depth - 1;
1657         border = path[depth].p_ext->ee_block;
1658         err = ext4_ext_get_access(handle, inode, path + k);
1659         if (err)
1660                 return err;
1661         path[k].p_idx->ei_block = border;
1662         err = ext4_ext_dirty(handle, inode, path + k);
1663         if (err)
1664                 return err;
1665
1666         while (k--) {
1667                 /* change all left-side indexes */
1668                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1669                         break;
1670                 err = ext4_ext_get_access(handle, inode, path + k);
1671                 if (err)
1672                         break;
1673                 path[k].p_idx->ei_block = border;
1674                 err = ext4_ext_dirty(handle, inode, path + k);
1675                 if (err)
1676                         break;
1677         }
1678
1679         return err;
1680 }
1681
1682 int
1683 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1684                                 struct ext4_extent *ex2)
1685 {
1686         unsigned short ext1_ee_len, ext2_ee_len;
1687
1688         /*
1689          * Make sure that both extents are initialized. We don't merge
1690          * unwritten extents so that we can be sure that end_io code has
1691          * the extent that was written properly split out and conversion to
1692          * initialized is trivial.
1693          */
1694         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1695                 return 0;
1696
1697         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1698         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1699
1700         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1701                         le32_to_cpu(ex2->ee_block))
1702                 return 0;
1703
1704         /*
1705          * To allow future support for preallocated extents to be added
1706          * as an RO_COMPAT feature, refuse to merge to extents if
1707          * this can result in the top bit of ee_len being set.
1708          */
1709         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1710                 return 0;
1711         if (ext4_ext_is_unwritten(ex1) &&
1712             (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1713              atomic_read(&EXT4_I(inode)->i_unwritten) ||
1714              (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1715                 return 0;
1716 #ifdef AGGRESSIVE_TEST
1717         if (ext1_ee_len >= 4)
1718                 return 0;
1719 #endif
1720
1721         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1722                 return 1;
1723         return 0;
1724 }
1725
1726 /*
1727  * This function tries to merge the "ex" extent to the next extent in the tree.
1728  * It always tries to merge towards right. If you want to merge towards
1729  * left, pass "ex - 1" as argument instead of "ex".
1730  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1731  * 1 if they got merged.
1732  */
1733 static int ext4_ext_try_to_merge_right(struct inode *inode,
1734                                  struct ext4_ext_path *path,
1735                                  struct ext4_extent *ex)
1736 {
1737         struct ext4_extent_header *eh;
1738         unsigned int depth, len;
1739         int merge_done = 0, unwritten;
1740
1741         depth = ext_depth(inode);
1742         BUG_ON(path[depth].p_hdr == NULL);
1743         eh = path[depth].p_hdr;
1744
1745         while (ex < EXT_LAST_EXTENT(eh)) {
1746                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1747                         break;
1748                 /* merge with next extent! */
1749                 unwritten = ext4_ext_is_unwritten(ex);
1750                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1751                                 + ext4_ext_get_actual_len(ex + 1));
1752                 if (unwritten)
1753                         ext4_ext_mark_unwritten(ex);
1754
1755                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1756                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1757                                 * sizeof(struct ext4_extent);
1758                         memmove(ex + 1, ex + 2, len);
1759                 }
1760                 le16_add_cpu(&eh->eh_entries, -1);
1761                 merge_done = 1;
1762                 WARN_ON(eh->eh_entries == 0);
1763                 if (!eh->eh_entries)
1764                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1765         }
1766
1767         return merge_done;
1768 }
1769
1770 /*
1771  * This function does a very simple check to see if we can collapse
1772  * an extent tree with a single extent tree leaf block into the inode.
1773  */
1774 static void ext4_ext_try_to_merge_up(handle_t *handle,
1775                                      struct inode *inode,
1776                                      struct ext4_ext_path *path)
1777 {
1778         size_t s;
1779         unsigned max_root = ext4_ext_space_root(inode, 0);
1780         ext4_fsblk_t blk;
1781
1782         if ((path[0].p_depth != 1) ||
1783             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1784             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1785                 return;
1786
1787         /*
1788          * We need to modify the block allocation bitmap and the block
1789          * group descriptor to release the extent tree block.  If we
1790          * can't get the journal credits, give up.
1791          */
1792         if (ext4_journal_extend(handle, 2))
1793                 return;
1794
1795         /*
1796          * Copy the extent data up to the inode
1797          */
1798         blk = ext4_idx_pblock(path[0].p_idx);
1799         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1800                 sizeof(struct ext4_extent_idx);
1801         s += sizeof(struct ext4_extent_header);
1802
1803         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1804         path[0].p_depth = 0;
1805         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1806                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1807         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1808
1809         brelse(path[1].p_bh);
1810         ext4_free_blocks(handle, inode, NULL, blk, 1,
1811                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET |
1812                          EXT4_FREE_BLOCKS_RESERVE);
1813 }
1814
1815 /*
1816  * This function tries to merge the @ex extent to neighbours in the tree.
1817  * return 1 if merge left else 0.
1818  */
1819 static void ext4_ext_try_to_merge(handle_t *handle,
1820                                   struct inode *inode,
1821                                   struct ext4_ext_path *path,
1822                                   struct ext4_extent *ex) {
1823         struct ext4_extent_header *eh;
1824         unsigned int depth;
1825         int merge_done = 0;
1826
1827         depth = ext_depth(inode);
1828         BUG_ON(path[depth].p_hdr == NULL);
1829         eh = path[depth].p_hdr;
1830
1831         if (ex > EXT_FIRST_EXTENT(eh))
1832                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1833
1834         if (!merge_done)
1835                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1836
1837         ext4_ext_try_to_merge_up(handle, inode, path);
1838 }
1839
1840 /*
1841  * check if a portion of the "newext" extent overlaps with an
1842  * existing extent.
1843  *
1844  * If there is an overlap discovered, it updates the length of the newext
1845  * such that there will be no overlap, and then returns 1.
1846  * If there is no overlap found, it returns 0.
1847  */
1848 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1849                                            struct inode *inode,
1850                                            struct ext4_extent *newext,
1851                                            struct ext4_ext_path *path)
1852 {
1853         ext4_lblk_t b1, b2;
1854         unsigned int depth, len1;
1855         unsigned int ret = 0;
1856
1857         b1 = le32_to_cpu(newext->ee_block);
1858         len1 = ext4_ext_get_actual_len(newext);
1859         depth = ext_depth(inode);
1860         if (!path[depth].p_ext)
1861                 goto out;
1862         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1863
1864         /*
1865          * get the next allocated block if the extent in the path
1866          * is before the requested block(s)
1867          */
1868         if (b2 < b1) {
1869                 b2 = ext4_ext_next_allocated_block(path);
1870                 if (b2 == EXT_MAX_BLOCKS)
1871                         goto out;
1872                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1873         }
1874
1875         /* check for wrap through zero on extent logical start block*/
1876         if (b1 + len1 < b1) {
1877                 len1 = EXT_MAX_BLOCKS - b1;
1878                 newext->ee_len = cpu_to_le16(len1);
1879                 ret = 1;
1880         }
1881
1882         /* check for overlap */
1883         if (b1 + len1 > b2) {
1884                 newext->ee_len = cpu_to_le16(b2 - b1);
1885                 ret = 1;
1886         }
1887 out:
1888         return ret;
1889 }
1890
1891 /*
1892  * ext4_ext_insert_extent:
1893  * tries to merge requsted extent into the existing extent or
1894  * inserts requested extent as new one into the tree,
1895  * creating new leaf in the no-space case.
1896  */
1897 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1898                                 struct ext4_ext_path *path,
1899                                 struct ext4_extent *newext, int gb_flags)
1900 {
1901         struct ext4_extent_header *eh;
1902         struct ext4_extent *ex, *fex;
1903         struct ext4_extent *nearex; /* nearest extent */
1904         struct ext4_ext_path *npath = NULL;
1905         int depth, len, err;
1906         ext4_lblk_t next;
1907         int mb_flags = 0, unwritten;
1908
1909         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1910                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1911                 return -EIO;
1912         }
1913         depth = ext_depth(inode);
1914         ex = path[depth].p_ext;
1915         eh = path[depth].p_hdr;
1916         if (unlikely(path[depth].p_hdr == NULL)) {
1917                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1918                 return -EIO;
1919         }
1920
1921         /* try to insert block into found extent and return */
1922         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1923
1924                 /*
1925                  * Try to see whether we should rather test the extent on
1926                  * right from ex, or from the left of ex. This is because
1927                  * ext4_ext_find_extent() can return either extent on the
1928                  * left, or on the right from the searched position. This
1929                  * will make merging more effective.
1930                  */
1931                 if (ex < EXT_LAST_EXTENT(eh) &&
1932                     (le32_to_cpu(ex->ee_block) +
1933                     ext4_ext_get_actual_len(ex) <
1934                     le32_to_cpu(newext->ee_block))) {
1935                         ex += 1;
1936                         goto prepend;
1937                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1938                            (le32_to_cpu(newext->ee_block) +
1939                            ext4_ext_get_actual_len(newext) <
1940                            le32_to_cpu(ex->ee_block)))
1941                         ex -= 1;
1942
1943                 /* Try to append newex to the ex */
1944                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1945                         ext_debug("append [%d]%d block to %u:[%d]%d"
1946                                   "(from %llu)\n",
1947                                   ext4_ext_is_unwritten(newext),
1948                                   ext4_ext_get_actual_len(newext),
1949                                   le32_to_cpu(ex->ee_block),
1950                                   ext4_ext_is_unwritten(ex),
1951                                   ext4_ext_get_actual_len(ex),
1952                                   ext4_ext_pblock(ex));
1953                         err = ext4_ext_get_access(handle, inode,
1954                                                   path + depth);
1955                         if (err)
1956                                 return err;
1957                         unwritten = ext4_ext_is_unwritten(ex);
1958                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1959                                         + ext4_ext_get_actual_len(newext));
1960                         if (unwritten)
1961                                 ext4_ext_mark_unwritten(ex);
1962                         eh = path[depth].p_hdr;
1963                         nearex = ex;
1964                         goto merge;
1965                 }
1966
1967 prepend:
1968                 /* Try to prepend newex to the ex */
1969                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
1970                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
1971                                   "(from %llu)\n",
1972                                   le32_to_cpu(newext->ee_block),
1973                                   ext4_ext_is_unwritten(newext),
1974                                   ext4_ext_get_actual_len(newext),
1975                                   le32_to_cpu(ex->ee_block),
1976                                   ext4_ext_is_unwritten(ex),
1977                                   ext4_ext_get_actual_len(ex),
1978                                   ext4_ext_pblock(ex));
1979                         err = ext4_ext_get_access(handle, inode,
1980                                                   path + depth);
1981                         if (err)
1982                                 return err;
1983
1984                         unwritten = ext4_ext_is_unwritten(ex);
1985                         ex->ee_block = newext->ee_block;
1986                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
1987                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1988                                         + ext4_ext_get_actual_len(newext));
1989                         if (unwritten)
1990                                 ext4_ext_mark_unwritten(ex);
1991                         eh = path[depth].p_hdr;
1992                         nearex = ex;
1993                         goto merge;
1994                 }
1995         }
1996
1997         depth = ext_depth(inode);
1998         eh = path[depth].p_hdr;
1999         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2000                 goto has_space;
2001
2002         /* probably next leaf has space for us? */
2003         fex = EXT_LAST_EXTENT(eh);
2004         next = EXT_MAX_BLOCKS;
2005         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2006                 next = ext4_ext_next_leaf_block(path);
2007         if (next != EXT_MAX_BLOCKS) {
2008                 ext_debug("next leaf block - %u\n", next);
2009                 BUG_ON(npath != NULL);
2010                 npath = ext4_ext_find_extent(inode, next, NULL, 0);
2011                 if (IS_ERR(npath))
2012                         return PTR_ERR(npath);
2013                 BUG_ON(npath->p_depth != path->p_depth);
2014                 eh = npath[depth].p_hdr;
2015                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2016                         ext_debug("next leaf isn't full(%d)\n",
2017                                   le16_to_cpu(eh->eh_entries));
2018                         path = npath;
2019                         goto has_space;
2020                 }
2021                 ext_debug("next leaf has no free space(%d,%d)\n",
2022                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2023         }
2024
2025         /*
2026          * There is no free space in the found leaf.
2027          * We're gonna add a new leaf in the tree.
2028          */
2029         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2030                 mb_flags = EXT4_MB_USE_RESERVED;
2031         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2032                                        path, newext);
2033         if (err)
2034                 goto cleanup;
2035         depth = ext_depth(inode);
2036         eh = path[depth].p_hdr;
2037
2038 has_space:
2039         nearex = path[depth].p_ext;
2040
2041         err = ext4_ext_get_access(handle, inode, path + depth);
2042         if (err)
2043                 goto cleanup;
2044
2045         if (!nearex) {
2046                 /* there is no extent in this leaf, create first one */
2047                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2048                                 le32_to_cpu(newext->ee_block),
2049                                 ext4_ext_pblock(newext),
2050                                 ext4_ext_is_unwritten(newext),
2051                                 ext4_ext_get_actual_len(newext));
2052                 nearex = EXT_FIRST_EXTENT(eh);
2053         } else {
2054                 if (le32_to_cpu(newext->ee_block)
2055                            > le32_to_cpu(nearex->ee_block)) {
2056                         /* Insert after */
2057                         ext_debug("insert %u:%llu:[%d]%d before: "
2058                                         "nearest %p\n",
2059                                         le32_to_cpu(newext->ee_block),
2060                                         ext4_ext_pblock(newext),
2061                                         ext4_ext_is_unwritten(newext),
2062                                         ext4_ext_get_actual_len(newext),
2063                                         nearex);
2064                         nearex++;
2065                 } else {
2066                         /* Insert before */
2067                         BUG_ON(newext->ee_block == nearex->ee_block);
2068                         ext_debug("insert %u:%llu:[%d]%d after: "
2069                                         "nearest %p\n",
2070                                         le32_to_cpu(newext->ee_block),
2071                                         ext4_ext_pblock(newext),
2072                                         ext4_ext_is_unwritten(newext),
2073                                         ext4_ext_get_actual_len(newext),
2074                                         nearex);
2075                 }
2076                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2077                 if (len > 0) {
2078                         ext_debug("insert %u:%llu:[%d]%d: "
2079                                         "move %d extents from 0x%p to 0x%p\n",
2080                                         le32_to_cpu(newext->ee_block),
2081                                         ext4_ext_pblock(newext),
2082                                         ext4_ext_is_unwritten(newext),
2083                                         ext4_ext_get_actual_len(newext),
2084                                         len, nearex, nearex + 1);
2085                         memmove(nearex + 1, nearex,
2086                                 len * sizeof(struct ext4_extent));
2087                 }
2088         }
2089
2090         le16_add_cpu(&eh->eh_entries, 1);
2091         path[depth].p_ext = nearex;
2092         nearex->ee_block = newext->ee_block;
2093         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2094         nearex->ee_len = newext->ee_len;
2095
2096 merge:
2097         /* try to merge extents */
2098         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2099                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2100
2101
2102         /* time to correct all indexes above */
2103         err = ext4_ext_correct_indexes(handle, inode, path);
2104         if (err)
2105                 goto cleanup;
2106
2107         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2108
2109 cleanup:
2110         if (npath) {
2111                 ext4_ext_drop_refs(npath);
2112                 kfree(npath);
2113         }
2114         return err;
2115 }
2116
2117 static int ext4_fill_fiemap_extents(struct inode *inode,
2118                                     ext4_lblk_t block, ext4_lblk_t num,
2119                                     struct fiemap_extent_info *fieinfo)
2120 {
2121         struct ext4_ext_path *path = NULL;
2122         struct ext4_extent *ex;
2123         struct extent_status es;
2124         ext4_lblk_t next, next_del, start = 0, end = 0;
2125         ext4_lblk_t last = block + num;
2126         int exists, depth = 0, err = 0;
2127         unsigned int flags = 0;
2128         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2129
2130         while (block < last && block != EXT_MAX_BLOCKS) {
2131                 num = last - block;
2132                 /* find extent for this block */
2133                 down_read(&EXT4_I(inode)->i_data_sem);
2134
2135                 if (path && ext_depth(inode) != depth) {
2136                         /* depth was changed. we have to realloc path */
2137                         kfree(path);
2138                         path = NULL;
2139                 }
2140
2141                 path = ext4_ext_find_extent(inode, block, path, 0);
2142                 if (IS_ERR(path)) {
2143                         up_read(&EXT4_I(inode)->i_data_sem);
2144                         err = PTR_ERR(path);
2145                         path = NULL;
2146                         break;
2147                 }
2148
2149                 depth = ext_depth(inode);
2150                 if (unlikely(path[depth].p_hdr == NULL)) {
2151                         up_read(&EXT4_I(inode)->i_data_sem);
2152                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2153                         err = -EIO;
2154                         break;
2155                 }
2156                 ex = path[depth].p_ext;
2157                 next = ext4_ext_next_allocated_block(path);
2158                 ext4_ext_drop_refs(path);
2159
2160                 flags = 0;
2161                 exists = 0;
2162                 if (!ex) {
2163                         /* there is no extent yet, so try to allocate
2164                          * all requested space */
2165                         start = block;
2166                         end = block + num;
2167                 } else if (le32_to_cpu(ex->ee_block) > block) {
2168                         /* need to allocate space before found extent */
2169                         start = block;
2170                         end = le32_to_cpu(ex->ee_block);
2171                         if (block + num < end)
2172                                 end = block + num;
2173                 } else if (block >= le32_to_cpu(ex->ee_block)
2174                                         + ext4_ext_get_actual_len(ex)) {
2175                         /* need to allocate space after found extent */
2176                         start = block;
2177                         end = block + num;
2178                         if (end >= next)
2179                                 end = next;
2180                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2181                         /*
2182                          * some part of requested space is covered
2183                          * by found extent
2184                          */
2185                         start = block;
2186                         end = le32_to_cpu(ex->ee_block)
2187                                 + ext4_ext_get_actual_len(ex);
2188                         if (block + num < end)
2189                                 end = block + num;
2190                         exists = 1;
2191                 } else {
2192                         BUG();
2193                 }
2194                 BUG_ON(end <= start);
2195
2196                 if (!exists) {
2197                         es.es_lblk = start;
2198                         es.es_len = end - start;
2199                         es.es_pblk = 0;
2200                 } else {
2201                         es.es_lblk = le32_to_cpu(ex->ee_block);
2202                         es.es_len = ext4_ext_get_actual_len(ex);
2203                         es.es_pblk = ext4_ext_pblock(ex);
2204                         if (ext4_ext_is_unwritten(ex))
2205                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2206                 }
2207
2208                 /*
2209                  * Find delayed extent and update es accordingly. We call
2210                  * it even in !exists case to find out whether es is the
2211                  * last existing extent or not.
2212                  */
2213                 next_del = ext4_find_delayed_extent(inode, &es);
2214                 if (!exists && next_del) {
2215                         exists = 1;
2216                         flags |= (FIEMAP_EXTENT_DELALLOC |
2217                                   FIEMAP_EXTENT_UNKNOWN);
2218                 }
2219                 up_read(&EXT4_I(inode)->i_data_sem);
2220
2221                 if (unlikely(es.es_len == 0)) {
2222                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2223                         err = -EIO;
2224                         break;
2225                 }
2226
2227                 /*
2228                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2229                  * we need to check next == EXT_MAX_BLOCKS because it is
2230                  * possible that an extent is with unwritten and delayed
2231                  * status due to when an extent is delayed allocated and
2232                  * is allocated by fallocate status tree will track both of
2233                  * them in a extent.
2234                  *
2235                  * So we could return a unwritten and delayed extent, and
2236                  * its block is equal to 'next'.
2237                  */
2238                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2239                         flags |= FIEMAP_EXTENT_LAST;
2240                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2241                                      next != EXT_MAX_BLOCKS)) {
2242                                 EXT4_ERROR_INODE(inode,
2243                                                  "next extent == %u, next "
2244                                                  "delalloc extent = %u",
2245                                                  next, next_del);
2246                                 err = -EIO;
2247                                 break;
2248                         }
2249                 }
2250
2251                 if (exists) {
2252                         err = fiemap_fill_next_extent(fieinfo,
2253                                 (__u64)es.es_lblk << blksize_bits,
2254                                 (__u64)es.es_pblk << blksize_bits,
2255                                 (__u64)es.es_len << blksize_bits,
2256                                 flags);
2257                         if (err < 0)
2258                                 break;
2259                         if (err == 1) {
2260                                 err = 0;
2261                                 break;
2262                         }
2263                 }
2264
2265                 block = es.es_lblk + es.es_len;
2266         }
2267
2268         if (path) {
2269                 ext4_ext_drop_refs(path);
2270                 kfree(path);
2271         }
2272
2273         return err;
2274 }
2275
2276 /*
2277  * ext4_ext_put_gap_in_cache:
2278  * calculate boundaries of the gap that the requested block fits into
2279  * and cache this gap
2280  */
2281 static void
2282 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
2283                                 ext4_lblk_t block)
2284 {
2285         int depth = ext_depth(inode);
2286         unsigned long len = 0;
2287         ext4_lblk_t lblock = 0;
2288         struct ext4_extent *ex;
2289
2290         ex = path[depth].p_ext;
2291         if (ex == NULL) {
2292                 /*
2293                  * there is no extent yet, so gap is [0;-] and we
2294                  * don't cache it
2295                  */
2296                 ext_debug("cache gap(whole file):");
2297         } else if (block < le32_to_cpu(ex->ee_block)) {
2298                 lblock = block;
2299                 len = le32_to_cpu(ex->ee_block) - block;
2300                 ext_debug("cache gap(before): %u [%u:%u]",
2301                                 block,
2302                                 le32_to_cpu(ex->ee_block),
2303                                  ext4_ext_get_actual_len(ex));
2304                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2305                         ext4_es_insert_extent(inode, lblock, len, ~0,
2306                                               EXTENT_STATUS_HOLE);
2307         } else if (block >= le32_to_cpu(ex->ee_block)
2308                         + ext4_ext_get_actual_len(ex)) {
2309                 ext4_lblk_t next;
2310                 lblock = le32_to_cpu(ex->ee_block)
2311                         + ext4_ext_get_actual_len(ex);
2312
2313                 next = ext4_ext_next_allocated_block(path);
2314                 ext_debug("cache gap(after): [%u:%u] %u",
2315                                 le32_to_cpu(ex->ee_block),
2316                                 ext4_ext_get_actual_len(ex),
2317                                 block);
2318                 BUG_ON(next == lblock);
2319                 len = next - lblock;
2320                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2321                         ext4_es_insert_extent(inode, lblock, len, ~0,
2322                                               EXTENT_STATUS_HOLE);
2323         } else {
2324                 BUG();
2325         }
2326
2327         ext_debug(" -> %u:%lu\n", lblock, len);
2328 }
2329
2330 /*
2331  * ext4_ext_rm_idx:
2332  * removes index from the index block.
2333  */
2334 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2335                         struct ext4_ext_path *path, int depth)
2336 {
2337         int err;
2338         ext4_fsblk_t leaf;
2339
2340         /* free index block */
2341         depth--;
2342         path = path + depth;
2343         leaf = ext4_idx_pblock(path->p_idx);
2344         if (unlikely(path->p_hdr->eh_entries == 0)) {
2345                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2346                 return -EIO;
2347         }
2348         err = ext4_ext_get_access(handle, inode, path);
2349         if (err)
2350                 return err;
2351
2352         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2353                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2354                 len *= sizeof(struct ext4_extent_idx);
2355                 memmove(path->p_idx, path->p_idx + 1, len);
2356         }
2357
2358         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2359         err = ext4_ext_dirty(handle, inode, path);
2360         if (err)
2361                 return err;
2362         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2363         trace_ext4_ext_rm_idx(inode, leaf);
2364
2365         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2366                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2367
2368         while (--depth >= 0) {
2369                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2370                         break;
2371                 path--;
2372                 err = ext4_ext_get_access(handle, inode, path);
2373                 if (err)
2374                         break;
2375                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2376                 err = ext4_ext_dirty(handle, inode, path);
2377                 if (err)
2378                         break;
2379         }
2380         return err;
2381 }
2382
2383 /*
2384  * ext4_ext_calc_credits_for_single_extent:
2385  * This routine returns max. credits that needed to insert an extent
2386  * to the extent tree.
2387  * When pass the actual path, the caller should calculate credits
2388  * under i_data_sem.
2389  */
2390 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2391                                                 struct ext4_ext_path *path)
2392 {
2393         if (path) {
2394                 int depth = ext_depth(inode);
2395                 int ret = 0;
2396
2397                 /* probably there is space in leaf? */
2398                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2399                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2400
2401                         /*
2402                          *  There are some space in the leaf tree, no
2403                          *  need to account for leaf block credit
2404                          *
2405                          *  bitmaps and block group descriptor blocks
2406                          *  and other metadata blocks still need to be
2407                          *  accounted.
2408                          */
2409                         /* 1 bitmap, 1 block group descriptor */
2410                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2411                         return ret;
2412                 }
2413         }
2414
2415         return ext4_chunk_trans_blocks(inode, nrblocks);
2416 }
2417
2418 /*
2419  * How many index/leaf blocks need to change/allocate to add @extents extents?
2420  *
2421  * If we add a single extent, then in the worse case, each tree level
2422  * index/leaf need to be changed in case of the tree split.
2423  *
2424  * If more extents are inserted, they could cause the whole tree split more
2425  * than once, but this is really rare.
2426  */
2427 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2428 {
2429         int index;
2430         int depth;
2431
2432         /* If we are converting the inline data, only one is needed here. */
2433         if (ext4_has_inline_data(inode))
2434                 return 1;
2435
2436         depth = ext_depth(inode);
2437
2438         if (extents <= 1)
2439                 index = depth * 2;
2440         else
2441                 index = depth * 3;
2442
2443         return index;
2444 }
2445
2446 static inline int get_default_free_blocks_flags(struct inode *inode)
2447 {
2448         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2449                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2450         else if (ext4_should_journal_data(inode))
2451                 return EXT4_FREE_BLOCKS_FORGET;
2452         return 0;
2453 }
2454
2455 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2456                               struct ext4_extent *ex,
2457                               long long *partial_cluster,
2458                               ext4_lblk_t from, ext4_lblk_t to)
2459 {
2460         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2461         unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2462         ext4_fsblk_t pblk;
2463         int flags = get_default_free_blocks_flags(inode);
2464
2465         /*
2466          * For bigalloc file systems, we never free a partial cluster
2467          * at the beginning of the extent.  Instead, we make a note
2468          * that we tried freeing the cluster, and check to see if we
2469          * need to free it on a subsequent call to ext4_remove_blocks,
2470          * or at the end of the ext4_truncate() operation.
2471          */
2472         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2473
2474         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2475         /*
2476          * If we have a partial cluster, and it's different from the
2477          * cluster of the last block, we need to explicitly free the
2478          * partial cluster here.
2479          */
2480         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2481         if ((*partial_cluster > 0) &&
2482             (EXT4_B2C(sbi, pblk) != *partial_cluster)) {
2483                 ext4_free_blocks(handle, inode, NULL,
2484                                  EXT4_C2B(sbi, *partial_cluster),
2485                                  sbi->s_cluster_ratio, flags);
2486                 *partial_cluster = 0;
2487         }
2488
2489 #ifdef EXTENTS_STATS
2490         {
2491                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2492                 spin_lock(&sbi->s_ext_stats_lock);
2493                 sbi->s_ext_blocks += ee_len;
2494                 sbi->s_ext_extents++;
2495                 if (ee_len < sbi->s_ext_min)
2496                         sbi->s_ext_min = ee_len;
2497                 if (ee_len > sbi->s_ext_max)
2498                         sbi->s_ext_max = ee_len;
2499                 if (ext_depth(inode) > sbi->s_depth_max)
2500                         sbi->s_depth_max = ext_depth(inode);
2501                 spin_unlock(&sbi->s_ext_stats_lock);
2502         }
2503 #endif
2504         if (from >= le32_to_cpu(ex->ee_block)
2505             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2506                 /* tail removal */
2507                 ext4_lblk_t num;
2508                 unsigned int unaligned;
2509
2510                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2511                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2512                 /*
2513                  * Usually we want to free partial cluster at the end of the
2514                  * extent, except for the situation when the cluster is still
2515                  * used by any other extent (partial_cluster is negative).
2516                  */
2517                 if (*partial_cluster < 0 &&
2518                     -(*partial_cluster) == EXT4_B2C(sbi, pblk + num - 1))
2519                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2520
2521                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2522                           num, pblk, *partial_cluster);
2523                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2524                 /*
2525                  * If the block range to be freed didn't start at the
2526                  * beginning of a cluster, and we removed the entire
2527                  * extent and the cluster is not used by any other extent,
2528                  * save the partial cluster here, since we might need to
2529                  * delete if we determine that the truncate operation has
2530                  * removed all of the blocks in the cluster.
2531                  *
2532                  * On the other hand, if we did not manage to free the whole
2533                  * extent, we have to mark the cluster as used (store negative
2534                  * cluster number in partial_cluster).
2535                  */
2536                 unaligned = EXT4_PBLK_COFF(sbi, pblk);
2537                 if (unaligned && (ee_len == num) &&
2538                     (*partial_cluster != -((long long)EXT4_B2C(sbi, pblk))))
2539                         *partial_cluster = EXT4_B2C(sbi, pblk);
2540                 else if (unaligned)
2541                         *partial_cluster = -((long long)EXT4_B2C(sbi, pblk));
2542                 else if (*partial_cluster > 0)
2543                         *partial_cluster = 0;
2544         } else
2545                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2546                            "%u-%u from %u:%u\n",
2547                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2548         return 0;
2549 }
2550
2551
2552 /*
2553  * ext4_ext_rm_leaf() Removes the extents associated with the
2554  * blocks appearing between "start" and "end", and splits the extents
2555  * if "start" and "end" appear in the same extent
2556  *
2557  * @handle: The journal handle
2558  * @inode:  The files inode
2559  * @path:   The path to the leaf
2560  * @partial_cluster: The cluster which we'll have to free if all extents
2561  *                   has been released from it. It gets negative in case
2562  *                   that the cluster is still used.
2563  * @start:  The first block to remove
2564  * @end:   The last block to remove
2565  */
2566 static int
2567 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2568                  struct ext4_ext_path *path,
2569                  long long *partial_cluster,
2570                  ext4_lblk_t start, ext4_lblk_t end)
2571 {
2572         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2573         int err = 0, correct_index = 0;
2574         int depth = ext_depth(inode), credits;
2575         struct ext4_extent_header *eh;
2576         ext4_lblk_t a, b;
2577         unsigned num;
2578         ext4_lblk_t ex_ee_block;
2579         unsigned short ex_ee_len;
2580         unsigned unwritten = 0;
2581         struct ext4_extent *ex;
2582         ext4_fsblk_t pblk;
2583
2584         /* the header must be checked already in ext4_ext_remove_space() */
2585         ext_debug("truncate since %u in leaf to %u\n", start, end);
2586         if (!path[depth].p_hdr)
2587                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2588         eh = path[depth].p_hdr;
2589         if (unlikely(path[depth].p_hdr == NULL)) {
2590                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2591                 return -EIO;
2592         }
2593         /* find where to start removing */
2594         ex = path[depth].p_ext;
2595         if (!ex)
2596                 ex = EXT_LAST_EXTENT(eh);
2597
2598         ex_ee_block = le32_to_cpu(ex->ee_block);
2599         ex_ee_len = ext4_ext_get_actual_len(ex);
2600
2601         /*
2602          * If we're starting with an extent other than the last one in the
2603          * node, we need to see if it shares a cluster with the extent to
2604          * the right (towards the end of the file). If its leftmost cluster
2605          * is this extent's rightmost cluster and it is not cluster aligned,
2606          * we'll mark it as a partial that is not to be deallocated.
2607          */
2608
2609         if (ex != EXT_LAST_EXTENT(eh)) {
2610                 ext4_fsblk_t current_pblk, right_pblk;
2611                 long long current_cluster, right_cluster;
2612
2613                 current_pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2614                 current_cluster = (long long)EXT4_B2C(sbi, current_pblk);
2615                 right_pblk = ext4_ext_pblock(ex + 1);
2616                 right_cluster = (long long)EXT4_B2C(sbi, right_pblk);
2617                 if (current_cluster == right_cluster &&
2618                         EXT4_PBLK_COFF(sbi, right_pblk))
2619                         *partial_cluster = -right_cluster;
2620         }
2621
2622         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2623
2624         while (ex >= EXT_FIRST_EXTENT(eh) &&
2625                         ex_ee_block + ex_ee_len > start) {
2626
2627                 if (ext4_ext_is_unwritten(ex))
2628                         unwritten = 1;
2629                 else
2630                         unwritten = 0;
2631
2632                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2633                           unwritten, ex_ee_len);
2634                 path[depth].p_ext = ex;
2635
2636                 a = ex_ee_block > start ? ex_ee_block : start;
2637                 b = ex_ee_block+ex_ee_len - 1 < end ?
2638                         ex_ee_block+ex_ee_len - 1 : end;
2639
2640                 ext_debug("  border %u:%u\n", a, b);
2641
2642                 /* If this extent is beyond the end of the hole, skip it */
2643                 if (end < ex_ee_block) {
2644                         /*
2645                          * We're going to skip this extent and move to another,
2646                          * so if this extent is not cluster aligned we have
2647                          * to mark the current cluster as used to avoid
2648                          * accidentally freeing it later on
2649                          */
2650                         pblk = ext4_ext_pblock(ex);
2651                         if (EXT4_PBLK_COFF(sbi, pblk))
2652                                 *partial_cluster =
2653                                         -((long long)EXT4_B2C(sbi, pblk));
2654                         ex--;
2655                         ex_ee_block = le32_to_cpu(ex->ee_block);
2656                         ex_ee_len = ext4_ext_get_actual_len(ex);
2657                         continue;
2658                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2659                         EXT4_ERROR_INODE(inode,
2660                                          "can not handle truncate %u:%u "
2661                                          "on extent %u:%u",
2662                                          start, end, ex_ee_block,
2663                                          ex_ee_block + ex_ee_len - 1);
2664                         err = -EIO;
2665                         goto out;
2666                 } else if (a != ex_ee_block) {
2667                         /* remove tail of the extent */
2668                         num = a - ex_ee_block;
2669                 } else {
2670                         /* remove whole extent: excellent! */
2671                         num = 0;
2672                 }
2673                 /*
2674                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2675                  * descriptor) for each block group; assume two block
2676                  * groups plus ex_ee_len/blocks_per_block_group for
2677                  * the worst case
2678                  */
2679                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2680                 if (ex == EXT_FIRST_EXTENT(eh)) {
2681                         correct_index = 1;
2682                         credits += (ext_depth(inode)) + 1;
2683                 }
2684                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2685
2686                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2687                 if (err)
2688                         goto out;
2689
2690                 err = ext4_ext_get_access(handle, inode, path + depth);
2691                 if (err)
2692                         goto out;
2693
2694                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2695                                          a, b);
2696                 if (err)
2697                         goto out;
2698
2699                 if (num == 0)
2700                         /* this extent is removed; mark slot entirely unused */
2701                         ext4_ext_store_pblock(ex, 0);
2702
2703                 ex->ee_len = cpu_to_le16(num);
2704                 /*
2705                  * Do not mark unwritten if all the blocks in the
2706                  * extent have been removed.
2707                  */
2708                 if (unwritten && num)
2709                         ext4_ext_mark_unwritten(ex);
2710                 /*
2711                  * If the extent was completely released,
2712                  * we need to remove it from the leaf
2713                  */
2714                 if (num == 0) {
2715                         if (end != EXT_MAX_BLOCKS - 1) {
2716                                 /*
2717                                  * For hole punching, we need to scoot all the
2718                                  * extents up when an extent is removed so that
2719                                  * we dont have blank extents in the middle
2720                                  */
2721                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2722                                         sizeof(struct ext4_extent));
2723
2724                                 /* Now get rid of the one at the end */
2725                                 memset(EXT_LAST_EXTENT(eh), 0,
2726                                         sizeof(struct ext4_extent));
2727                         }
2728                         le16_add_cpu(&eh->eh_entries, -1);
2729                 } else if (*partial_cluster > 0)
2730                         *partial_cluster = 0;
2731
2732                 err = ext4_ext_dirty(handle, inode, path + depth);
2733                 if (err)
2734                         goto out;
2735
2736                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2737                                 ext4_ext_pblock(ex));
2738                 ex--;
2739                 ex_ee_block = le32_to_cpu(ex->ee_block);
2740                 ex_ee_len = ext4_ext_get_actual_len(ex);
2741         }
2742
2743         if (correct_index && eh->eh_entries)
2744                 err = ext4_ext_correct_indexes(handle, inode, path);
2745
2746         /*
2747          * If there's a partial cluster and at least one extent remains in
2748          * the leaf, free the partial cluster if it isn't shared with the
2749          * current extent.  If there's a partial cluster and no extents
2750          * remain in the leaf, it can't be freed here.  It can only be
2751          * freed when it's possible to determine if it's not shared with
2752          * any other extent - when the next leaf is processed or when space
2753          * removal is complete.
2754          */
2755         if (*partial_cluster > 0 && eh->eh_entries &&
2756             (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) !=
2757              *partial_cluster)) {
2758                 int flags = get_default_free_blocks_flags(inode);
2759
2760                 ext4_free_blocks(handle, inode, NULL,
2761                                  EXT4_C2B(sbi, *partial_cluster),
2762                                  sbi->s_cluster_ratio, flags);
2763                 *partial_cluster = 0;
2764         }
2765
2766         /* if this leaf is free, then we should
2767          * remove it from index block above */
2768         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2769                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2770
2771 out:
2772         return err;
2773 }
2774
2775 /*
2776  * ext4_ext_more_to_rm:
2777  * returns 1 if current index has to be freed (even partial)
2778  */
2779 static int
2780 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2781 {
2782         BUG_ON(path->p_idx == NULL);
2783
2784         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2785                 return 0;
2786
2787         /*
2788          * if truncate on deeper level happened, it wasn't partial,
2789          * so we have to consider current index for truncation
2790          */
2791         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2792                 return 0;
2793         return 1;
2794 }
2795
2796 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2797                           ext4_lblk_t end)
2798 {
2799         struct super_block *sb = inode->i_sb;
2800         int depth = ext_depth(inode);
2801         struct ext4_ext_path *path = NULL;
2802         long long partial_cluster = 0;
2803         handle_t *handle;
2804         int i = 0, err = 0;
2805
2806         ext_debug("truncate since %u to %u\n", start, end);
2807
2808         /* probably first extent we're gonna free will be last in block */
2809         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2810         if (IS_ERR(handle))
2811                 return PTR_ERR(handle);
2812
2813 again:
2814         trace_ext4_ext_remove_space(inode, start, end, depth);
2815
2816         /*
2817          * Check if we are removing extents inside the extent tree. If that
2818          * is the case, we are going to punch a hole inside the extent tree
2819          * so we have to check whether we need to split the extent covering
2820          * the last block to remove so we can easily remove the part of it
2821          * in ext4_ext_rm_leaf().
2822          */
2823         if (end < EXT_MAX_BLOCKS - 1) {
2824                 struct ext4_extent *ex;
2825                 ext4_lblk_t ee_block;
2826
2827                 /* find extent for this block */
2828                 path = ext4_ext_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2829                 if (IS_ERR(path)) {
2830                         ext4_journal_stop(handle);
2831                         return PTR_ERR(path);
2832                 }
2833                 depth = ext_depth(inode);
2834                 /* Leaf not may not exist only if inode has no blocks at all */
2835                 ex = path[depth].p_ext;
2836                 if (!ex) {
2837                         if (depth) {
2838                                 EXT4_ERROR_INODE(inode,
2839                                                  "path[%d].p_hdr == NULL",
2840                                                  depth);
2841                                 err = -EIO;
2842                         }
2843                         goto out;
2844                 }
2845
2846                 ee_block = le32_to_cpu(ex->ee_block);
2847
2848                 /*
2849                  * See if the last block is inside the extent, if so split
2850                  * the extent at 'end' block so we can easily remove the
2851                  * tail of the first part of the split extent in
2852                  * ext4_ext_rm_leaf().
2853                  */
2854                 if (end >= ee_block &&
2855                     end < ee_block + ext4_ext_get_actual_len(ex) - 1) {
2856                         int split_flag = 0;
2857
2858                         if (ext4_ext_is_unwritten(ex))
2859                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
2860                                              EXT4_EXT_MARK_UNWRIT2;
2861
2862                         /*
2863                          * Split the extent in two so that 'end' is the last
2864                          * block in the first new extent. Also we should not
2865                          * fail removing space due to ENOSPC so try to use
2866                          * reserved block if that happens.
2867                          */
2868                         err = ext4_split_extent_at(handle, inode, path,
2869                                         end + 1, split_flag,
2870                                         EXT4_EX_NOCACHE |
2871                                         EXT4_GET_BLOCKS_PRE_IO |
2872                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
2873
2874                         if (err < 0)
2875                                 goto out;
2876                 }
2877         }
2878         /*
2879          * We start scanning from right side, freeing all the blocks
2880          * after i_size and walking into the tree depth-wise.
2881          */
2882         depth = ext_depth(inode);
2883         if (path) {
2884                 int k = i = depth;
2885                 while (--k > 0)
2886                         path[k].p_block =
2887                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2888         } else {
2889                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2890                                GFP_NOFS);
2891                 if (path == NULL) {
2892                         ext4_journal_stop(handle);
2893                         return -ENOMEM;
2894                 }
2895                 path[0].p_depth = depth;
2896                 path[0].p_hdr = ext_inode_hdr(inode);
2897                 i = 0;
2898
2899                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2900                         err = -EIO;
2901                         goto out;
2902                 }
2903         }
2904         err = 0;
2905
2906         while (i >= 0 && err == 0) {
2907                 if (i == depth) {
2908                         /* this is leaf block */
2909                         err = ext4_ext_rm_leaf(handle, inode, path,
2910                                                &partial_cluster, start,
2911                                                end);
2912                         /* root level has p_bh == NULL, brelse() eats this */
2913                         brelse(path[i].p_bh);
2914                         path[i].p_bh = NULL;
2915                         i--;
2916                         continue;
2917                 }
2918
2919                 /* this is index block */
2920                 if (!path[i].p_hdr) {
2921                         ext_debug("initialize header\n");
2922                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2923                 }
2924
2925                 if (!path[i].p_idx) {
2926                         /* this level hasn't been touched yet */
2927                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2928                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2929                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2930                                   path[i].p_hdr,
2931                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2932                 } else {
2933                         /* we were already here, see at next index */
2934                         path[i].p_idx--;
2935                 }
2936
2937                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2938                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2939                                 path[i].p_idx);
2940                 if (ext4_ext_more_to_rm(path + i)) {
2941                         struct buffer_head *bh;
2942                         /* go to the next level */
2943                         ext_debug("move to level %d (block %llu)\n",
2944                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2945                         memset(path + i + 1, 0, sizeof(*path));
2946                         bh = read_extent_tree_block(inode,
2947                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2948                                 EXT4_EX_NOCACHE);
2949                         if (IS_ERR(bh)) {
2950                                 /* should we reset i_size? */
2951                                 err = PTR_ERR(bh);
2952                                 break;
2953                         }
2954                         /* Yield here to deal with large extent trees.
2955                          * Should be a no-op if we did IO above. */
2956                         cond_resched();
2957                         if (WARN_ON(i + 1 > depth)) {
2958                                 err = -EIO;
2959                                 break;
2960                         }
2961                         path[i + 1].p_bh = bh;
2962
2963                         /* save actual number of indexes since this
2964                          * number is changed at the next iteration */
2965                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2966                         i++;
2967                 } else {
2968                         /* we finished processing this index, go up */
2969                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2970                                 /* index is empty, remove it;
2971                                  * handle must be already prepared by the
2972                                  * truncatei_leaf() */
2973                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2974                         }
2975                         /* root level has p_bh == NULL, brelse() eats this */
2976                         brelse(path[i].p_bh);
2977                         path[i].p_bh = NULL;
2978                         i--;
2979                         ext_debug("return to level %d\n", i);
2980                 }
2981         }
2982
2983         trace_ext4_ext_remove_space_done(inode, start, end, depth,
2984                         partial_cluster, path->p_hdr->eh_entries);
2985
2986         /* If we still have something in the partial cluster and we have removed
2987          * even the first extent, then we should free the blocks in the partial
2988          * cluster as well. */
2989         if (partial_cluster > 0 && path->p_hdr->eh_entries == 0) {
2990                 int flags = get_default_free_blocks_flags(inode);
2991
2992                 ext4_free_blocks(handle, inode, NULL,
2993                                  EXT4_C2B(EXT4_SB(sb), partial_cluster),
2994                                  EXT4_SB(sb)->s_cluster_ratio, flags);
2995                 partial_cluster = 0;
2996         }
2997
2998         /* TODO: flexible tree reduction should be here */
2999         if (path->p_hdr->eh_entries == 0) {
3000                 /*
3001                  * truncate to zero freed all the tree,
3002                  * so we need to correct eh_depth
3003                  */
3004                 err = ext4_ext_get_access(handle, inode, path);
3005                 if (err == 0) {
3006                         ext_inode_hdr(inode)->eh_depth = 0;
3007                         ext_inode_hdr(inode)->eh_max =
3008                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3009                         err = ext4_ext_dirty(handle, inode, path);
3010                 }
3011         }
3012 out:
3013         ext4_ext_drop_refs(path);
3014         kfree(path);
3015         if (err == -EAGAIN) {
3016                 path = NULL;
3017                 goto again;
3018         }
3019         ext4_journal_stop(handle);
3020
3021         return err;
3022 }
3023
3024 /*
3025  * called at mount time
3026  */
3027 void ext4_ext_init(struct super_block *sb)
3028 {
3029         /*
3030          * possible initialization would be here
3031          */
3032
3033         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
3034 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3035                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3036 #ifdef AGGRESSIVE_TEST
3037                        ", aggressive tests"
3038 #endif
3039 #ifdef CHECK_BINSEARCH
3040                        ", check binsearch"
3041 #endif
3042 #ifdef EXTENTS_STATS
3043                        ", stats"
3044 #endif
3045                        "\n");
3046 #endif
3047 #ifdef EXTENTS_STATS
3048                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3049                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3050                 EXT4_SB(sb)->s_ext_max = 0;
3051 #endif
3052         }
3053 }
3054
3055 /*
3056  * called at umount time
3057  */
3058 void ext4_ext_release(struct super_block *sb)
3059 {
3060         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
3061                 return;
3062
3063 #ifdef EXTENTS_STATS
3064         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3065                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3066                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3067                         sbi->s_ext_blocks, sbi->s_ext_extents,
3068                         sbi->s_ext_blocks / sbi->s_ext_extents);
3069                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3070                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3071         }
3072 #endif
3073 }
3074
3075 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3076 {
3077         ext4_lblk_t  ee_block;
3078         ext4_fsblk_t ee_pblock;
3079         unsigned int ee_len;
3080
3081         ee_block  = le32_to_cpu(ex->ee_block);
3082         ee_len    = ext4_ext_get_actual_len(ex);
3083         ee_pblock = ext4_ext_pblock(ex);
3084
3085         if (ee_len == 0)
3086                 return 0;
3087
3088         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3089                                      EXTENT_STATUS_WRITTEN);
3090 }
3091
3092 /* FIXME!! we need to try to merge to left or right after zero-out  */
3093 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3094 {
3095         ext4_fsblk_t ee_pblock;
3096         unsigned int ee_len;
3097         int ret;
3098
3099         ee_len    = ext4_ext_get_actual_len(ex);
3100         ee_pblock = ext4_ext_pblock(ex);
3101
3102         ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
3103         if (ret > 0)
3104                 ret = 0;
3105
3106         return ret;
3107 }
3108
3109 /*
3110  * ext4_split_extent_at() splits an extent at given block.
3111  *
3112  * @handle: the journal handle
3113  * @inode: the file inode
3114  * @path: the path to the extent
3115  * @split: the logical block where the extent is splitted.
3116  * @split_flags: indicates if the extent could be zeroout if split fails, and
3117  *               the states(init or unwritten) of new extents.
3118  * @flags: flags used to insert new extent to extent tree.
3119  *
3120  *
3121  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3122  * of which are deterimined by split_flag.
3123  *
3124  * There are two cases:
3125  *  a> the extent are splitted into two extent.
3126  *  b> split is not needed, and just mark the extent.
3127  *
3128  * return 0 on success.
3129  */
3130 static int ext4_split_extent_at(handle_t *handle,
3131                              struct inode *inode,
3132                              struct ext4_ext_path *path,
3133                              ext4_lblk_t split,
3134                              int split_flag,
3135                              int flags)
3136 {
3137         ext4_fsblk_t newblock;
3138         ext4_lblk_t ee_block;
3139         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3140         struct ext4_extent *ex2 = NULL;
3141         unsigned int ee_len, depth;
3142         int err = 0;
3143
3144         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3145                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3146
3147         ext_debug("ext4_split_extents_at: inode %lu, logical"
3148                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3149
3150         ext4_ext_show_leaf(inode, path);
3151
3152         depth = ext_depth(inode);
3153         ex = path[depth].p_ext;
3154         ee_block = le32_to_cpu(ex->ee_block);
3155         ee_len = ext4_ext_get_actual_len(ex);
3156         newblock = split - ee_block + ext4_ext_pblock(ex);
3157
3158         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3159         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3160                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3161                              EXT4_EXT_MARK_UNWRIT1 |
3162                              EXT4_EXT_MARK_UNWRIT2));
3163
3164         err = ext4_ext_get_access(handle, inode, path + depth);
3165         if (err)
3166                 goto out;
3167
3168         if (split == ee_block) {
3169                 /*
3170                  * case b: block @split is the block that the extent begins with
3171                  * then we just change the state of the extent, and splitting
3172                  * is not needed.
3173                  */
3174                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3175                         ext4_ext_mark_unwritten(ex);
3176                 else
3177                         ext4_ext_mark_initialized(ex);
3178
3179                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3180                         ext4_ext_try_to_merge(handle, inode, path, ex);
3181
3182                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3183                 goto out;
3184         }
3185
3186         /* case a */
3187         memcpy(&orig_ex, ex, sizeof(orig_ex));
3188         ex->ee_len = cpu_to_le16(split - ee_block);
3189         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3190                 ext4_ext_mark_unwritten(ex);
3191
3192         /*
3193          * path may lead to new leaf, not to original leaf any more
3194          * after ext4_ext_insert_extent() returns,
3195          */
3196         err = ext4_ext_dirty(handle, inode, path + depth);
3197         if (err)
3198                 goto fix_extent_len;
3199
3200         ex2 = &newex;
3201         ex2->ee_block = cpu_to_le32(split);
3202         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3203         ext4_ext_store_pblock(ex2, newblock);
3204         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3205                 ext4_ext_mark_unwritten(ex2);
3206
3207         err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
3208         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3209                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3210                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3211                                 err = ext4_ext_zeroout(inode, ex2);
3212                                 zero_ex.ee_block = ex2->ee_block;
3213                                 zero_ex.ee_len = cpu_to_le16(
3214                                                 ext4_ext_get_actual_len(ex2));
3215                                 ext4_ext_store_pblock(&zero_ex,
3216                                                       ext4_ext_pblock(ex2));
3217                         } else {
3218                                 err = ext4_ext_zeroout(inode, ex);
3219                                 zero_ex.ee_block = ex->ee_block;
3220                                 zero_ex.ee_len = cpu_to_le16(
3221                                                 ext4_ext_get_actual_len(ex));
3222                                 ext4_ext_store_pblock(&zero_ex,
3223                                                       ext4_ext_pblock(ex));
3224                         }
3225                 } else {
3226                         err = ext4_ext_zeroout(inode, &orig_ex);
3227                         zero_ex.ee_block = orig_ex.ee_block;
3228                         zero_ex.ee_len = cpu_to_le16(
3229                                                 ext4_ext_get_actual_len(&orig_ex));
3230                         ext4_ext_store_pblock(&zero_ex,
3231                                               ext4_ext_pblock(&orig_ex));
3232                 }
3233
3234                 if (err)
3235                         goto fix_extent_len;
3236                 /* update the extent length and mark as initialized */
3237                 ex->ee_len = cpu_to_le16(ee_len);
3238                 ext4_ext_try_to_merge(handle, inode, path, ex);
3239                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3240                 if (err)
3241                         goto fix_extent_len;
3242
3243                 /* update extent status tree */
3244                 err = ext4_zeroout_es(inode, &zero_ex);
3245
3246                 goto out;
3247         } else if (err)
3248                 goto fix_extent_len;
3249
3250 out:
3251         ext4_ext_show_leaf(inode, path);
3252         return err;
3253
3254 fix_extent_len:
3255         ex->ee_len = orig_ex.ee_len;
3256         ext4_ext_dirty(handle, inode, path + depth);
3257         return err;
3258 }
3259
3260 /*
3261  * ext4_split_extents() splits an extent and mark extent which is covered
3262  * by @map as split_flags indicates
3263  *
3264  * It may result in splitting the extent into multiple extents (up to three)
3265  * There are three possibilities:
3266  *   a> There is no split required
3267  *   b> Splits in two extents: Split is happening at either end of the extent
3268  *   c> Splits in three extents: Somone is splitting in middle of the extent
3269  *
3270  */
3271 static int ext4_split_extent(handle_t *handle,
3272                               struct inode *inode,
3273                               struct ext4_ext_path *path,
3274                               struct ext4_map_blocks *map,
3275                               int split_flag,
3276                               int flags)
3277 {
3278         ext4_lblk_t ee_block;
3279         struct ext4_extent *ex;
3280         unsigned int ee_len, depth;
3281         int err = 0;
3282         int unwritten;
3283         int split_flag1, flags1;
3284         int allocated = map->m_len;
3285
3286         depth = ext_depth(inode);
3287         ex = path[depth].p_ext;
3288         ee_block = le32_to_cpu(ex->ee_block);
3289         ee_len = ext4_ext_get_actual_len(ex);
3290         unwritten = ext4_ext_is_unwritten(ex);
3291
3292         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3293                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3294                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3295                 if (unwritten)
3296                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3297                                        EXT4_EXT_MARK_UNWRIT2;
3298                 if (split_flag & EXT4_EXT_DATA_VALID2)
3299                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3300                 err = ext4_split_extent_at(handle, inode, path,
3301                                 map->m_lblk + map->m_len, split_flag1, flags1);
3302                 if (err)
3303                         goto out;
3304         } else {
3305                 allocated = ee_len - (map->m_lblk - ee_block);
3306         }
3307         /*
3308          * Update path is required because previous ext4_split_extent_at() may
3309          * result in split of original leaf or extent zeroout.
3310          */
3311         ext4_ext_drop_refs(path);
3312         path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3313         if (IS_ERR(path))
3314                 return PTR_ERR(path);
3315         depth = ext_depth(inode);
3316         ex = path[depth].p_ext;
3317         if (!ex) {
3318                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3319                                  (unsigned long) map->m_lblk);
3320                 return -EIO;
3321         }
3322         unwritten = ext4_ext_is_unwritten(ex);
3323         split_flag1 = 0;
3324
3325         if (map->m_lblk >= ee_block) {
3326                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3327                 if (unwritten) {
3328                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3329                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3330                                                      EXT4_EXT_MARK_UNWRIT2);
3331                 }
3332                 err = ext4_split_extent_at(handle, inode, path,
3333                                 map->m_lblk, split_flag1, flags);
3334                 if (err)
3335                         goto out;
3336         }
3337
3338         ext4_ext_show_leaf(inode, path);
3339 out:
3340         return err ? err : allocated;
3341 }
3342
3343 /*
3344  * This function is called by ext4_ext_map_blocks() if someone tries to write
3345  * to an unwritten extent. It may result in splitting the unwritten
3346  * extent into multiple extents (up to three - one initialized and two
3347  * unwritten).
3348  * There are three possibilities:
3349  *   a> There is no split required: Entire extent should be initialized
3350  *   b> Splits in two extents: Write is happening at either end of the extent
3351  *   c> Splits in three extents: Somone is writing in middle of the extent
3352  *
3353  * Pre-conditions:
3354  *  - The extent pointed to by 'path' is unwritten.
3355  *  - The extent pointed to by 'path' contains a superset
3356  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3357  *
3358  * Post-conditions on success:
3359  *  - the returned value is the number of blocks beyond map->l_lblk
3360  *    that are allocated and initialized.
3361  *    It is guaranteed to be >= map->m_len.
3362  */
3363 static int ext4_ext_convert_to_initialized(handle_t *handle,
3364                                            struct inode *inode,
3365                                            struct ext4_map_blocks *map,
3366                                            struct ext4_ext_path *path,
3367                                            int flags)
3368 {
3369         struct ext4_sb_info *sbi;
3370         struct ext4_extent_header *eh;
3371         struct ext4_map_blocks split_map;
3372         struct ext4_extent zero_ex;
3373         struct ext4_extent *ex, *abut_ex;
3374         ext4_lblk_t ee_block, eof_block;
3375         unsigned int ee_len, depth, map_len = map->m_len;
3376         int allocated = 0, max_zeroout = 0;
3377         int err = 0;
3378         int split_flag = 0;
3379
3380         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3381                 "block %llu, max_blocks %u\n", inode->i_ino,
3382                 (unsigned long long)map->m_lblk, map_len);
3383
3384         sbi = EXT4_SB(inode->i_sb);
3385         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3386                 inode->i_sb->s_blocksize_bits;
3387         if (eof_block < map->m_lblk + map_len)
3388                 eof_block = map->m_lblk + map_len;
3389
3390         depth = ext_depth(inode);
3391         eh = path[depth].p_hdr;
3392         ex = path[depth].p_ext;
3393         ee_block = le32_to_cpu(ex->ee_block);
3394         ee_len = ext4_ext_get_actual_len(ex);
3395         zero_ex.ee_len = 0;
3396
3397         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3398
3399         /* Pre-conditions */
3400         BUG_ON(!ext4_ext_is_unwritten(ex));
3401         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3402
3403         /*
3404          * Attempt to transfer newly initialized blocks from the currently
3405          * unwritten extent to its neighbor. This is much cheaper
3406          * than an insertion followed by a merge as those involve costly
3407          * memmove() calls. Transferring to the left is the common case in
3408          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3409          * followed by append writes.
3410          *
3411          * Limitations of the current logic:
3412          *  - L1: we do not deal with writes covering the whole extent.
3413          *    This would require removing the extent if the transfer
3414          *    is possible.
3415          *  - L2: we only attempt to merge with an extent stored in the
3416          *    same extent tree node.
3417          */
3418         if ((map->m_lblk == ee_block) &&
3419                 /* See if we can merge left */
3420                 (map_len < ee_len) &&           /*L1*/
3421                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3422                 ext4_lblk_t prev_lblk;
3423                 ext4_fsblk_t prev_pblk, ee_pblk;
3424                 unsigned int prev_len;
3425
3426                 abut_ex = ex - 1;
3427                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3428                 prev_len = ext4_ext_get_actual_len(abut_ex);
3429                 prev_pblk = ext4_ext_pblock(abut_ex);
3430                 ee_pblk = ext4_ext_pblock(ex);
3431
3432                 /*
3433                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3434                  * upon those conditions:
3435                  * - C1: abut_ex is initialized,
3436                  * - C2: abut_ex is logically abutting ex,
3437                  * - C3: abut_ex is physically abutting ex,
3438                  * - C4: abut_ex can receive the additional blocks without
3439                  *   overflowing the (initialized) length limit.
3440                  */
3441                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3442                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3443                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3444                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3445                         err = ext4_ext_get_access(handle, inode, path + depth);
3446                         if (err)
3447                                 goto out;
3448
3449                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3450                                 map, ex, abut_ex);
3451
3452                         /* Shift the start of ex by 'map_len' blocks */
3453                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3454                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3455                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3456                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3457
3458                         /* Extend abut_ex by 'map_len' blocks */
3459                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3460
3461                         /* Result: number of initialized blocks past m_lblk */
3462                         allocated = map_len;
3463                 }
3464         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3465                    (map_len < ee_len) &&        /*L1*/
3466                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3467                 /* See if we can merge right */
3468                 ext4_lblk_t next_lblk;
3469                 ext4_fsblk_t next_pblk, ee_pblk;
3470                 unsigned int next_len;
3471
3472                 abut_ex = ex + 1;
3473                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3474                 next_len = ext4_ext_get_actual_len(abut_ex);
3475                 next_pblk = ext4_ext_pblock(abut_ex);
3476                 ee_pblk = ext4_ext_pblock(ex);
3477
3478                 /*
3479                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3480                  * upon those conditions:
3481                  * - C1: abut_ex is initialized,
3482                  * - C2: abut_ex is logically abutting ex,
3483                  * - C3: abut_ex is physically abutting ex,
3484                  * - C4: abut_ex can receive the additional blocks without
3485                  *   overflowing the (initialized) length limit.
3486                  */
3487                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3488                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3489                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3490                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3491                         err = ext4_ext_get_access(handle, inode, path + depth);
3492                         if (err)
3493                                 goto out;
3494
3495                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3496                                 map, ex, abut_ex);
3497
3498                         /* Shift the start of abut_ex by 'map_len' blocks */
3499                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3500                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3501                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3502                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3503
3504                         /* Extend abut_ex by 'map_len' blocks */
3505                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3506
3507                         /* Result: number of initialized blocks past m_lblk */
3508                         allocated = map_len;
3509                 }
3510         }
3511         if (allocated) {
3512                 /* Mark the block containing both extents as dirty */
3513                 ext4_ext_dirty(handle, inode, path + depth);
3514
3515                 /* Update path to point to the right extent */
3516                 path[depth].p_ext = abut_ex;
3517                 goto out;
3518         } else
3519                 allocated = ee_len - (map->m_lblk - ee_block);
3520
3521         WARN_ON(map->m_lblk < ee_block);
3522         /*
3523          * It is safe to convert extent to initialized via explicit
3524          * zeroout only if extent is fully inside i_size or new_size.
3525          */
3526         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3527
3528         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3529                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3530                         (inode->i_sb->s_blocksize_bits - 10);
3531
3532         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3533         if (max_zeroout && (ee_len <= max_zeroout)) {
3534                 err = ext4_ext_zeroout(inode, ex);
3535                 if (err)
3536                         goto out;
3537                 zero_ex.ee_block = ex->ee_block;
3538                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3539                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3540
3541                 err = ext4_ext_get_access(handle, inode, path + depth);
3542                 if (err)
3543                         goto out;
3544                 ext4_ext_mark_initialized(ex);
3545                 ext4_ext_try_to_merge(handle, inode, path, ex);
3546                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3547                 goto out;
3548         }
3549
3550         /*
3551          * four cases:
3552          * 1. split the extent into three extents.
3553          * 2. split the extent into two extents, zeroout the first half.
3554          * 3. split the extent into two extents, zeroout the second half.
3555          * 4. split the extent into two extents with out zeroout.
3556          */
3557         split_map.m_lblk = map->m_lblk;
3558         split_map.m_len = map->m_len;
3559
3560         if (max_zeroout && (allocated > map->m_len)) {
3561                 if (allocated <= max_zeroout) {
3562                         /* case 3 */
3563                         zero_ex.ee_block =
3564                                          cpu_to_le32(map->m_lblk);
3565                         zero_ex.ee_len = cpu_to_le16(allocated);
3566                         ext4_ext_store_pblock(&zero_ex,
3567                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3568                         err = ext4_ext_zeroout(inode, &zero_ex);
3569                         if (err)
3570                                 goto out;
3571                         split_map.m_lblk = map->m_lblk;
3572                         split_map.m_len = allocated;
3573                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3574                         /* case 2 */
3575                         if (map->m_lblk != ee_block) {
3576                                 zero_ex.ee_block = ex->ee_block;
3577                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3578                                                         ee_block);
3579                                 ext4_ext_store_pblock(&zero_ex,
3580                                                       ext4_ext_pblock(ex));
3581                                 err = ext4_ext_zeroout(inode, &zero_ex);
3582                                 if (err)
3583                                         goto out;
3584                         }
3585
3586                         split_map.m_lblk = ee_block;
3587                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3588                         allocated = map->m_len;
3589                 }
3590         }
3591
3592         allocated = ext4_split_extent(handle, inode, path,
3593                                       &split_map, split_flag, flags);
3594         if (allocated < 0)
3595                 err = allocated;
3596
3597 out:
3598         /* If we have gotten a failure, don't zero out status tree */
3599         if (!err)
3600                 err = ext4_zeroout_es(inode, &zero_ex);
3601         return err ? err : allocated;
3602 }
3603
3604 /*
3605  * This function is called by ext4_ext_map_blocks() from
3606  * ext4_get_blocks_dio_write() when DIO to write
3607  * to an unwritten extent.
3608  *
3609  * Writing to an unwritten extent may result in splitting the unwritten
3610  * extent into multiple initialized/unwritten extents (up to three)
3611  * There are three possibilities:
3612  *   a> There is no split required: Entire extent should be unwritten
3613  *   b> Splits in two extents: Write is happening at either end of the extent
3614  *   c> Splits in three extents: Somone is writing in middle of the extent
3615  *
3616  * This works the same way in the case of initialized -> unwritten conversion.
3617  *
3618  * One of more index blocks maybe needed if the extent tree grow after
3619  * the unwritten extent split. To prevent ENOSPC occur at the IO
3620  * complete, we need to split the unwritten extent before DIO submit
3621  * the IO. The unwritten extent called at this time will be split
3622  * into three unwritten extent(at most). After IO complete, the part
3623  * being filled will be convert to initialized by the end_io callback function
3624  * via ext4_convert_unwritten_extents().
3625  *
3626  * Returns the size of unwritten extent to be written on success.
3627  */
3628 static int ext4_split_convert_extents(handle_t *handle,
3629                                         struct inode *inode,
3630                                         struct ext4_map_blocks *map,
3631                                         struct ext4_ext_path *path,
3632                                         int flags)
3633 {
3634         ext4_lblk_t eof_block;
3635         ext4_lblk_t ee_block;
3636         struct ext4_extent *ex;
3637         unsigned int ee_len;
3638         int split_flag = 0, depth;
3639
3640         ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3641                   __func__, inode->i_ino,
3642                   (unsigned long long)map->m_lblk, map->m_len);
3643
3644         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3645                 inode->i_sb->s_blocksize_bits;
3646         if (eof_block < map->m_lblk + map->m_len)
3647                 eof_block = map->m_lblk + map->m_len;
3648         /*
3649          * It is safe to convert extent to initialized via explicit
3650          * zeroout only if extent is fully insde i_size or new_size.
3651          */
3652         depth = ext_depth(inode);
3653         ex = path[depth].p_ext;
3654         ee_block = le32_to_cpu(ex->ee_block);
3655         ee_len = ext4_ext_get_actual_len(ex);
3656
3657         /* Convert to unwritten */
3658         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3659                 split_flag |= EXT4_EXT_DATA_VALID1;
3660         /* Convert to initialized */
3661         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3662                 split_flag |= ee_block + ee_len <= eof_block ?
3663                               EXT4_EXT_MAY_ZEROOUT : 0;
3664                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3665         }
3666         flags |= EXT4_GET_BLOCKS_PRE_IO;
3667         return ext4_split_extent(handle, inode, path, map, split_flag, flags);
3668 }
3669
3670 static int ext4_convert_initialized_extents(handle_t *handle,
3671                                             struct inode *inode,
3672                                             struct ext4_map_blocks *map,
3673                                             struct ext4_ext_path *path)
3674 {
3675         struct ext4_extent *ex;
3676         ext4_lblk_t ee_block;
3677         unsigned int ee_len;
3678         int depth;
3679         int err = 0;
3680
3681         depth = ext_depth(inode);
3682         ex = path[depth].p_ext;
3683         ee_block = le32_to_cpu(ex->ee_block);
3684         ee_len = ext4_ext_get_actual_len(ex);
3685
3686         ext_debug("%s: inode %lu, logical"
3687                 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3688                   (unsigned long long)ee_block, ee_len);
3689
3690         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3691                 err = ext4_split_convert_extents(handle, inode, map, path,
3692                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3693                 if (err < 0)
3694                         goto out;
3695                 ext4_ext_drop_refs(path);
3696                 path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3697                 if (IS_ERR(path)) {
3698                         err = PTR_ERR(path);
3699                         goto out;
3700                 }
3701                 depth = ext_depth(inode);
3702                 ex = path[depth].p_ext;
3703                 if (!ex) {
3704                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3705                                          (unsigned long) map->m_lblk);
3706                         err = -EIO;
3707                         goto out;
3708                 }
3709         }
3710
3711         err = ext4_ext_get_access(handle, inode, path + depth);
3712         if (err)
3713                 goto out;
3714         /* first mark the extent as unwritten */
3715         ext4_ext_mark_unwritten(ex);
3716
3717         /* note: ext4_ext_correct_indexes() isn't needed here because
3718          * borders are not changed
3719          */
3720         ext4_ext_try_to_merge(handle, inode, path, ex);
3721
3722         /* Mark modified extent as dirty */
3723         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3724 out:
3725         ext4_ext_show_leaf(inode, path);
3726         return err;
3727 }
3728
3729
3730 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3731                                                 struct inode *inode,
3732                                                 struct ext4_map_blocks *map,
3733                                                 struct ext4_ext_path *path)
3734 {
3735         struct ext4_extent *ex;
3736         ext4_lblk_t ee_block;
3737         unsigned int ee_len;
3738         int depth;
3739         int err = 0;
3740
3741         depth = ext_depth(inode);
3742         ex = path[depth].p_ext;
3743         ee_block = le32_to_cpu(ex->ee_block);
3744         ee_len = ext4_ext_get_actual_len(ex);
3745
3746         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3747                 "block %llu, max_blocks %u\n", inode->i_ino,
3748                   (unsigned long long)ee_block, ee_len);
3749
3750         /* If extent is larger than requested it is a clear sign that we still
3751          * have some extent state machine issues left. So extent_split is still
3752          * required.
3753          * TODO: Once all related issues will be fixed this situation should be
3754          * illegal.
3755          */
3756         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3757 #ifdef EXT4_DEBUG
3758                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3759                              " len %u; IO logical block %llu, len %u\n",
3760                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3761                              (unsigned long long)map->m_lblk, map->m_len);
3762 #endif
3763                 err = ext4_split_convert_extents(handle, inode, map, path,
3764                                                  EXT4_GET_BLOCKS_CONVERT);
3765                 if (err < 0)
3766                         goto out;
3767                 ext4_ext_drop_refs(path);
3768                 path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3769                 if (IS_ERR(path)) {
3770                         err = PTR_ERR(path);
3771                         goto out;
3772                 }
3773                 depth = ext_depth(inode);
3774                 ex = path[depth].p_ext;
3775         }
3776
3777         err = ext4_ext_get_access(handle, inode, path + depth);
3778         if (err)
3779                 goto out;
3780         /* first mark the extent as initialized */
3781         ext4_ext_mark_initialized(ex);
3782
3783         /* note: ext4_ext_correct_indexes() isn't needed here because
3784          * borders are not changed
3785          */
3786         ext4_ext_try_to_merge(handle, inode, path, ex);
3787
3788         /* Mark modified extent as dirty */
3789         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3790 out:
3791         ext4_ext_show_leaf(inode, path);
3792         return err;
3793 }
3794
3795 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3796                         sector_t block, int count)
3797 {
3798         int i;
3799         for (i = 0; i < count; i++)
3800                 unmap_underlying_metadata(bdev, block + i);
3801 }
3802
3803 /*
3804  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3805  */
3806 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3807                               ext4_lblk_t lblk,
3808                               struct ext4_ext_path *path,
3809                               unsigned int len)
3810 {
3811         int i, depth;
3812         struct ext4_extent_header *eh;
3813         struct ext4_extent *last_ex;
3814
3815         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3816                 return 0;
3817
3818         depth = ext_depth(inode);
3819         eh = path[depth].p_hdr;
3820
3821         /*
3822          * We're going to remove EOFBLOCKS_FL entirely in future so we
3823          * do not care for this case anymore. Simply remove the flag
3824          * if there are no extents.
3825          */
3826         if (unlikely(!eh->eh_entries))
3827                 goto out;
3828         last_ex = EXT_LAST_EXTENT(eh);
3829         /*
3830          * We should clear the EOFBLOCKS_FL flag if we are writing the
3831          * last block in the last extent in the file.  We test this by
3832          * first checking to see if the caller to
3833          * ext4_ext_get_blocks() was interested in the last block (or
3834          * a block beyond the last block) in the current extent.  If
3835          * this turns out to be false, we can bail out from this
3836          * function immediately.
3837          */
3838         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3839             ext4_ext_get_actual_len(last_ex))
3840                 return 0;
3841         /*
3842          * If the caller does appear to be planning to write at or
3843          * beyond the end of the current extent, we then test to see
3844          * if the current extent is the last extent in the file, by
3845          * checking to make sure it was reached via the rightmost node
3846          * at each level of the tree.
3847          */
3848         for (i = depth-1; i >= 0; i--)
3849                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3850                         return 0;
3851 out:
3852         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3853         return ext4_mark_inode_dirty(handle, inode);
3854 }
3855
3856 /**
3857  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3858  *
3859  * Return 1 if there is a delalloc block in the range, otherwise 0.
3860  */
3861 int ext4_find_delalloc_range(struct inode *inode,
3862                              ext4_lblk_t lblk_start,
3863                              ext4_lblk_t lblk_end)
3864 {
3865         struct extent_status es;
3866
3867         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3868         if (es.es_len == 0)
3869                 return 0; /* there is no delay extent in this tree */
3870         else if (es.es_lblk <= lblk_start &&
3871                  lblk_start < es.es_lblk + es.es_len)
3872                 return 1;
3873         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3874                 return 1;
3875         else
3876                 return 0;
3877 }
3878
3879 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3880 {
3881         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3882         ext4_lblk_t lblk_start, lblk_end;
3883         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3884         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3885
3886         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3887 }
3888
3889 /**
3890  * Determines how many complete clusters (out of those specified by the 'map')
3891  * are under delalloc and were reserved quota for.
3892  * This function is called when we are writing out the blocks that were
3893  * originally written with their allocation delayed, but then the space was
3894  * allocated using fallocate() before the delayed allocation could be resolved.
3895  * The cases to look for are:
3896  * ('=' indicated delayed allocated blocks
3897  *  '-' indicates non-delayed allocated blocks)
3898  * (a) partial clusters towards beginning and/or end outside of allocated range
3899  *     are not delalloc'ed.
3900  *      Ex:
3901  *      |----c---=|====c====|====c====|===-c----|
3902  *               |++++++ allocated ++++++|
3903  *      ==> 4 complete clusters in above example
3904  *
3905  * (b) partial cluster (outside of allocated range) towards either end is
3906  *     marked for delayed allocation. In this case, we will exclude that
3907  *     cluster.
3908  *      Ex:
3909  *      |----====c========|========c========|
3910  *           |++++++ allocated ++++++|
3911  *      ==> 1 complete clusters in above example
3912  *
3913  *      Ex:
3914  *      |================c================|
3915  *            |++++++ allocated ++++++|
3916  *      ==> 0 complete clusters in above example
3917  *
3918  * The ext4_da_update_reserve_space will be called only if we
3919  * determine here that there were some "entire" clusters that span
3920  * this 'allocated' range.
3921  * In the non-bigalloc case, this function will just end up returning num_blks
3922  * without ever calling ext4_find_delalloc_range.
3923  */
3924 static unsigned int
3925 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3926                            unsigned int num_blks)
3927 {
3928         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3929         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3930         ext4_lblk_t lblk_from, lblk_to, c_offset;
3931         unsigned int allocated_clusters = 0;
3932
3933         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3934         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3935
3936         /* max possible clusters for this allocation */
3937         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3938
3939         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3940
3941         /* Check towards left side */
3942         c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3943         if (c_offset) {
3944                 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3945                 lblk_to = lblk_from + c_offset - 1;
3946
3947                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3948                         allocated_clusters--;
3949         }
3950
3951         /* Now check towards right. */
3952         c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3953         if (allocated_clusters && c_offset) {
3954                 lblk_from = lblk_start + num_blks;
3955                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3956
3957                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3958                         allocated_clusters--;
3959         }
3960
3961         return allocated_clusters;
3962 }
3963
3964 static int
3965 ext4_ext_convert_initialized_extent(handle_t *handle, struct inode *inode,
3966                         struct ext4_map_blocks *map,
3967                         struct ext4_ext_path *path, int flags,
3968                         unsigned int allocated, ext4_fsblk_t newblock)
3969 {
3970         int ret = 0;
3971         int err = 0;
3972
3973         /*
3974          * Make sure that the extent is no bigger than we support with
3975          * unwritten extent
3976          */
3977         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3978                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3979
3980         ret = ext4_convert_initialized_extents(handle, inode, map,
3981                                                 path);
3982         if (ret >= 0) {
3983                 ext4_update_inode_fsync_trans(handle, inode, 1);
3984                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
3985                                          path, map->m_len);
3986         } else
3987                 err = ret;
3988         map->m_flags |= EXT4_MAP_UNWRITTEN;
3989         if (allocated > map->m_len)
3990                 allocated = map->m_len;
3991         map->m_len = allocated;
3992
3993         return err ? err : allocated;
3994 }
3995
3996 static int
3997 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3998                         struct ext4_map_blocks *map,
3999                         struct ext4_ext_path *path, int flags,
4000                         unsigned int allocated, ext4_fsblk_t newblock)
4001 {
4002         int ret = 0;
4003         int err = 0;
4004         ext4_io_end_t *io = ext4_inode_aio(inode);
4005
4006         ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4007                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
4008                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4009                   flags, allocated);
4010         ext4_ext_show_leaf(inode, path);
4011
4012         /*
4013          * When writing into unwritten space, we should not fail to
4014          * allocate metadata blocks for the new extent block if needed.
4015          */
4016         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4017
4018         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4019                                                     allocated, newblock);
4020
4021         /* get_block() before submit the IO, split the extent */
4022         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4023                 ret = ext4_split_convert_extents(handle, inode, map,
4024                                          path, flags | EXT4_GET_BLOCKS_CONVERT);
4025                 if (ret <= 0)
4026                         goto out;
4027                 /*
4028                  * Flag the inode(non aio case) or end_io struct (aio case)
4029                  * that this IO needs to conversion to written when IO is
4030                  * completed
4031                  */
4032                 if (io)
4033                         ext4_set_io_unwritten_flag(inode, io);
4034                 else
4035                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
4036                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4037                 goto out;
4038         }
4039         /* IO end_io complete, convert the filled extent to written */
4040         if (flags & EXT4_GET_BLOCKS_CONVERT) {
4041                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4042                                                         path);
4043                 if (ret >= 0) {
4044                         ext4_update_inode_fsync_trans(handle, inode, 1);
4045                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
4046                                                  path, map->m_len);
4047                 } else
4048                         err = ret;
4049                 map->m_flags |= EXT4_MAP_MAPPED;
4050                 map->m_pblk = newblock;
4051                 if (allocated > map->m_len)
4052                         allocated = map->m_len;
4053                 map->m_len = allocated;
4054                 goto out2;
4055         }
4056         /* buffered IO case */
4057         /*
4058          * repeat fallocate creation request
4059          * we already have an unwritten extent
4060          */
4061         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4062                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4063                 goto map_out;
4064         }
4065
4066         /* buffered READ or buffered write_begin() lookup */
4067         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4068                 /*
4069                  * We have blocks reserved already.  We
4070                  * return allocated blocks so that delalloc
4071                  * won't do block reservation for us.  But
4072                  * the buffer head will be unmapped so that
4073                  * a read from the block returns 0s.
4074                  */
4075                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4076                 goto out1;
4077         }
4078
4079         /* buffered write, writepage time, convert*/
4080         ret = ext4_ext_convert_to_initialized(handle, inode, map, path, flags);
4081         if (ret >= 0)
4082                 ext4_update_inode_fsync_trans(handle, inode, 1);
4083 out:
4084         if (ret <= 0) {
4085                 err = ret;
4086                 goto out2;
4087         } else
4088                 allocated = ret;
4089         map->m_flags |= EXT4_MAP_NEW;
4090         /*
4091          * if we allocated more blocks than requested
4092          * we need to make sure we unmap the extra block
4093          * allocated. The actual needed block will get
4094          * unmapped later when we find the buffer_head marked
4095          * new.
4096          */
4097         if (allocated > map->m_len) {
4098                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4099                                         newblock + map->m_len,
4100                                         allocated - map->m_len);
4101                 allocated = map->m_len;
4102         }
4103         map->m_len = allocated;
4104
4105         /*
4106          * If we have done fallocate with the offset that is already
4107          * delayed allocated, we would have block reservation
4108          * and quota reservation done in the delayed write path.
4109          * But fallocate would have already updated quota and block
4110          * count for this offset. So cancel these reservation
4111          */
4112         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4113                 unsigned int reserved_clusters;
4114                 reserved_clusters = get_reserved_cluster_alloc(inode,
4115                                 map->m_lblk, map->m_len);
4116                 if (reserved_clusters)
4117                         ext4_da_update_reserve_space(inode,
4118                                                      reserved_clusters,
4119                                                      0);
4120         }
4121
4122 map_out:
4123         map->m_flags |= EXT4_MAP_MAPPED;
4124         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4125                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4126                                          map->m_len);
4127                 if (err < 0)
4128                         goto out2;
4129         }
4130 out1:
4131         if (allocated > map->m_len)
4132                 allocated = map->m_len;
4133         ext4_ext_show_leaf(inode, path);
4134         map->m_pblk = newblock;
4135         map->m_len = allocated;
4136 out2:
4137         return err ? err : allocated;
4138 }
4139
4140 /*
4141  * get_implied_cluster_alloc - check to see if the requested
4142  * allocation (in the map structure) overlaps with a cluster already
4143  * allocated in an extent.
4144  *      @sb     The filesystem superblock structure
4145  *      @map    The requested lblk->pblk mapping
4146  *      @ex     The extent structure which might contain an implied
4147  *                      cluster allocation
4148  *
4149  * This function is called by ext4_ext_map_blocks() after we failed to
4150  * find blocks that were already in the inode's extent tree.  Hence,
4151  * we know that the beginning of the requested region cannot overlap
4152  * the extent from the inode's extent tree.  There are three cases we
4153  * want to catch.  The first is this case:
4154  *
4155  *               |--- cluster # N--|
4156  *    |--- extent ---|  |---- requested region ---|
4157  *                      |==========|
4158  *
4159  * The second case that we need to test for is this one:
4160  *
4161  *   |--------- cluster # N ----------------|
4162  *         |--- requested region --|   |------- extent ----|
4163  *         |=======================|
4164  *
4165  * The third case is when the requested region lies between two extents
4166  * within the same cluster:
4167  *          |------------- cluster # N-------------|
4168  * |----- ex -----|                  |---- ex_right ----|
4169  *                  |------ requested region ------|
4170  *                  |================|
4171  *
4172  * In each of the above cases, we need to set the map->m_pblk and
4173  * map->m_len so it corresponds to the return the extent labelled as
4174  * "|====|" from cluster #N, since it is already in use for data in
4175  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4176  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4177  * as a new "allocated" block region.  Otherwise, we will return 0 and
4178  * ext4_ext_map_blocks() will then allocate one or more new clusters
4179  * by calling ext4_mb_new_blocks().
4180  */
4181 static int get_implied_cluster_alloc(struct super_block *sb,
4182                                      struct ext4_map_blocks *map,
4183                                      struct ext4_extent *ex,
4184                                      struct ext4_ext_path *path)
4185 {
4186         struct ext4_sb_info *sbi = EXT4_SB(sb);
4187         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4188         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4189         ext4_lblk_t rr_cluster_start;
4190         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4191         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4192         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4193
4194         /* The extent passed in that we are trying to match */
4195         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4196         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4197
4198         /* The requested region passed into ext4_map_blocks() */
4199         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4200
4201         if ((rr_cluster_start == ex_cluster_end) ||
4202             (rr_cluster_start == ex_cluster_start)) {
4203                 if (rr_cluster_start == ex_cluster_end)
4204                         ee_start += ee_len - 1;
4205                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4206                 map->m_len = min(map->m_len,
4207                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4208                 /*
4209                  * Check for and handle this case:
4210                  *
4211                  *   |--------- cluster # N-------------|
4212                  *                     |------- extent ----|
4213                  *         |--- requested region ---|
4214                  *         |===========|
4215                  */
4216
4217                 if (map->m_lblk < ee_block)
4218                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4219
4220                 /*
4221                  * Check for the case where there is already another allocated
4222                  * block to the right of 'ex' but before the end of the cluster.
4223                  *
4224                  *          |------------- cluster # N-------------|
4225                  * |----- ex -----|                  |---- ex_right ----|
4226                  *                  |------ requested region ------|
4227                  *                  |================|
4228                  */
4229                 if (map->m_lblk > ee_block) {
4230                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4231                         map->m_len = min(map->m_len, next - map->m_lblk);
4232                 }
4233
4234                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4235                 return 1;
4236         }
4237
4238         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4239         return 0;
4240 }
4241
4242
4243 /*
4244  * Block allocation/map/preallocation routine for extents based files
4245  *
4246  *
4247  * Need to be called with
4248  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4249  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4250  *
4251  * return > 0, number of of blocks already mapped/allocated
4252  *          if create == 0 and these are pre-allocated blocks
4253  *              buffer head is unmapped
4254  *          otherwise blocks are mapped
4255  *
4256  * return = 0, if plain look up failed (blocks have not been allocated)
4257  *          buffer head is unmapped
4258  *
4259  * return < 0, error case.
4260  */
4261 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4262                         struct ext4_map_blocks *map, int flags)
4263 {
4264         struct ext4_ext_path *path = NULL;
4265         struct ext4_extent newex, *ex, *ex2;
4266         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4267         ext4_fsblk_t newblock = 0;
4268         int free_on_err = 0, err = 0, depth, ret;
4269         unsigned int allocated = 0, offset = 0;
4270         unsigned int allocated_clusters = 0;
4271         struct ext4_allocation_request ar;
4272         ext4_io_end_t *io = ext4_inode_aio(inode);
4273         ext4_lblk_t cluster_offset;
4274         int set_unwritten = 0;
4275
4276         ext_debug("blocks %u/%u requested for inode %lu\n",
4277                   map->m_lblk, map->m_len, inode->i_ino);
4278         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4279
4280         /* find extent for this block */
4281         path = ext4_ext_find_extent(inode, map->m_lblk, NULL, 0);
4282         if (IS_ERR(path)) {
4283                 err = PTR_ERR(path);
4284                 path = NULL;
4285                 goto out2;
4286         }
4287
4288         depth = ext_depth(inode);
4289
4290         /*
4291          * consistent leaf must not be empty;
4292          * this situation is possible, though, _during_ tree modification;
4293          * this is why assert can't be put in ext4_ext_find_extent()
4294          */
4295         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4296                 EXT4_ERROR_INODE(inode, "bad extent address "
4297                                  "lblock: %lu, depth: %d pblock %lld",
4298                                  (unsigned long) map->m_lblk, depth,
4299                                  path[depth].p_block);
4300                 err = -EIO;
4301                 goto out2;
4302         }
4303
4304         ex = path[depth].p_ext;
4305         if (ex) {
4306                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4307                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4308                 unsigned short ee_len;
4309
4310
4311                 /*
4312                  * unwritten extents are treated as holes, except that
4313                  * we split out initialized portions during a write.
4314                  */
4315                 ee_len = ext4_ext_get_actual_len(ex);
4316
4317                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4318
4319                 /* if found extent covers block, simply return it */
4320                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4321                         newblock = map->m_lblk - ee_block + ee_start;
4322                         /* number of remaining blocks in the extent */
4323                         allocated = ee_len - (map->m_lblk - ee_block);
4324                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4325                                   ee_block, ee_len, newblock);
4326
4327                         /*
4328                          * If the extent is initialized check whether the
4329                          * caller wants to convert it to unwritten.
4330                          */
4331                         if ((!ext4_ext_is_unwritten(ex)) &&
4332                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4333                                 allocated = ext4_ext_convert_initialized_extent(
4334                                                 handle, inode, map, path, flags,
4335                                                 allocated, newblock);
4336                                 goto out2;
4337                         } else if (!ext4_ext_is_unwritten(ex))
4338                                 goto out;
4339
4340                         ret = ext4_ext_handle_unwritten_extents(
4341                                 handle, inode, map, path, flags,
4342                                 allocated, newblock);
4343                         if (ret < 0)
4344                                 err = ret;
4345                         else
4346                                 allocated = ret;
4347                         goto out2;
4348                 }
4349         }
4350
4351         if ((sbi->s_cluster_ratio > 1) &&
4352             ext4_find_delalloc_cluster(inode, map->m_lblk))
4353                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4354
4355         /*
4356          * requested block isn't allocated yet;
4357          * we couldn't try to create block if create flag is zero
4358          */
4359         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4360                 /*
4361                  * put just found gap into cache to speed up
4362                  * subsequent requests
4363                  */
4364                 if ((flags & EXT4_GET_BLOCKS_NO_PUT_HOLE) == 0)
4365                         ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
4366                 goto out2;
4367         }
4368
4369         /*
4370          * Okay, we need to do block allocation.
4371          */
4372         map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
4373         newex.ee_block = cpu_to_le32(map->m_lblk);
4374         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4375
4376         /*
4377          * If we are doing bigalloc, check to see if the extent returned
4378          * by ext4_ext_find_extent() implies a cluster we can use.
4379          */
4380         if (cluster_offset && ex &&
4381             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4382                 ar.len = allocated = map->m_len;
4383                 newblock = map->m_pblk;
4384                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4385                 goto got_allocated_blocks;
4386         }
4387
4388         /* find neighbour allocated blocks */
4389         ar.lleft = map->m_lblk;
4390         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4391         if (err)
4392                 goto out2;
4393         ar.lright = map->m_lblk;
4394         ex2 = NULL;
4395         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4396         if (err)
4397                 goto out2;
4398
4399         /* Check if the extent after searching to the right implies a
4400          * cluster we can use. */
4401         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4402             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4403                 ar.len = allocated = map->m_len;
4404                 newblock = map->m_pblk;
4405                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4406                 goto got_allocated_blocks;
4407         }
4408
4409         /*
4410          * See if request is beyond maximum number of blocks we can have in
4411          * a single extent. For an initialized extent this limit is
4412          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4413          * EXT_UNWRITTEN_MAX_LEN.
4414          */
4415         if (map->m_len > EXT_INIT_MAX_LEN &&
4416             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4417                 map->m_len = EXT_INIT_MAX_LEN;
4418         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4419                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4420                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4421
4422         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4423         newex.ee_len = cpu_to_le16(map->m_len);
4424         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4425         if (err)
4426                 allocated = ext4_ext_get_actual_len(&newex);
4427         else
4428                 allocated = map->m_len;
4429
4430         /* allocate new block */
4431         ar.inode = inode;
4432         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4433         ar.logical = map->m_lblk;
4434         /*
4435          * We calculate the offset from the beginning of the cluster
4436          * for the logical block number, since when we allocate a
4437          * physical cluster, the physical block should start at the
4438          * same offset from the beginning of the cluster.  This is
4439          * needed so that future calls to get_implied_cluster_alloc()
4440          * work correctly.
4441          */
4442         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4443         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4444         ar.goal -= offset;
4445         ar.logical -= offset;
4446         if (S_ISREG(inode->i_mode))
4447                 ar.flags = EXT4_MB_HINT_DATA;
4448         else
4449                 /* disable in-core preallocation for non-regular files */
4450                 ar.flags = 0;
4451         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4452                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4453         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4454         if (!newblock)
4455                 goto out2;
4456         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4457                   ar.goal, newblock, allocated);
4458         free_on_err = 1;
4459         allocated_clusters = ar.len;
4460         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4461         if (ar.len > allocated)
4462                 ar.len = allocated;
4463
4464 got_allocated_blocks:
4465         /* try to insert new extent into found leaf and return */
4466         ext4_ext_store_pblock(&newex, newblock + offset);
4467         newex.ee_len = cpu_to_le16(ar.len);
4468         /* Mark unwritten */
4469         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4470                 ext4_ext_mark_unwritten(&newex);
4471                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4472                 /*
4473                  * io_end structure was created for every IO write to an
4474                  * unwritten extent. To avoid unnecessary conversion,
4475                  * here we flag the IO that really needs the conversion.
4476                  * For non asycn direct IO case, flag the inode state
4477                  * that we need to perform conversion when IO is done.
4478                  */
4479                 if (flags & EXT4_GET_BLOCKS_PRE_IO)
4480                         set_unwritten = 1;
4481         }
4482
4483         err = 0;
4484         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4485                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4486                                          path, ar.len);
4487         if (!err)
4488                 err = ext4_ext_insert_extent(handle, inode, path,
4489                                              &newex, flags);
4490
4491         if (!err && set_unwritten) {
4492                 if (io)
4493                         ext4_set_io_unwritten_flag(inode, io);
4494                 else
4495                         ext4_set_inode_state(inode,
4496                                              EXT4_STATE_DIO_UNWRITTEN);
4497         }
4498
4499         if (err && free_on_err) {
4500                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4501                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4502                 /* free data blocks we just allocated */
4503                 /* not a good idea to call discard here directly,
4504                  * but otherwise we'd need to call it every free() */
4505                 ext4_discard_preallocations(inode);
4506                 ext4_free_blocks(handle, inode, NULL, newblock,
4507                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4508                 goto out2;
4509         }
4510
4511         /* previous routine could use block we allocated */
4512         newblock = ext4_ext_pblock(&newex);
4513         allocated = ext4_ext_get_actual_len(&newex);
4514         if (allocated > map->m_len)
4515                 allocated = map->m_len;
4516         map->m_flags |= EXT4_MAP_NEW;
4517
4518         /*
4519          * Update reserved blocks/metadata blocks after successful
4520          * block allocation which had been deferred till now.
4521          */
4522         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4523                 unsigned int reserved_clusters;
4524                 /*
4525                  * Check how many clusters we had reserved this allocated range
4526                  */
4527                 reserved_clusters = get_reserved_cluster_alloc(inode,
4528                                                 map->m_lblk, allocated);
4529                 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) {
4530                         if (reserved_clusters) {
4531                                 /*
4532                                  * We have clusters reserved for this range.
4533                                  * But since we are not doing actual allocation
4534                                  * and are simply using blocks from previously
4535                                  * allocated cluster, we should release the
4536                                  * reservation and not claim quota.
4537                                  */
4538                                 ext4_da_update_reserve_space(inode,
4539                                                 reserved_clusters, 0);
4540                         }
4541                 } else {
4542                         BUG_ON(allocated_clusters < reserved_clusters);
4543                         if (reserved_clusters < allocated_clusters) {
4544                                 struct ext4_inode_info *ei = EXT4_I(inode);
4545                                 int reservation = allocated_clusters -
4546                                                   reserved_clusters;
4547                                 /*
4548                                  * It seems we claimed few clusters outside of
4549                                  * the range of this allocation. We should give
4550                                  * it back to the reservation pool. This can
4551                                  * happen in the following case:
4552                                  *
4553                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4554                                  *   cluster has 4 blocks. Thus, the clusters
4555                                  *   are [0-3],[4-7],[8-11]...
4556                                  * * First comes delayed allocation write for
4557                                  *   logical blocks 10 & 11. Since there were no
4558                                  *   previous delayed allocated blocks in the
4559                                  *   range [8-11], we would reserve 1 cluster
4560                                  *   for this write.
4561                                  * * Next comes write for logical blocks 3 to 8.
4562                                  *   In this case, we will reserve 2 clusters
4563                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4564                                  *   that range has a delayed allocated blocks.
4565                                  *   Thus total reserved clusters now becomes 3.
4566                                  * * Now, during the delayed allocation writeout
4567                                  *   time, we will first write blocks [3-8] and
4568                                  *   allocate 3 clusters for writing these
4569                                  *   blocks. Also, we would claim all these
4570                                  *   three clusters above.
4571                                  * * Now when we come here to writeout the
4572                                  *   blocks [10-11], we would expect to claim
4573                                  *   the reservation of 1 cluster we had made
4574                                  *   (and we would claim it since there are no
4575                                  *   more delayed allocated blocks in the range
4576                                  *   [8-11]. But our reserved cluster count had
4577                                  *   already gone to 0.
4578                                  *
4579                                  *   Thus, at the step 4 above when we determine
4580                                  *   that there are still some unwritten delayed
4581                                  *   allocated blocks outside of our current
4582                                  *   block range, we should increment the
4583                                  *   reserved clusters count so that when the
4584                                  *   remaining blocks finally gets written, we
4585                                  *   could claim them.
4586                                  */
4587                                 dquot_reserve_block(inode,
4588                                                 EXT4_C2B(sbi, reservation));
4589                                 spin_lock(&ei->i_block_reservation_lock);
4590                                 ei->i_reserved_data_blocks += reservation;
4591                                 spin_unlock(&ei->i_block_reservation_lock);
4592                         }
4593                         /*
4594                          * We will claim quota for all newly allocated blocks.
4595                          * We're updating the reserved space *after* the
4596                          * correction above so we do not accidentally free
4597                          * all the metadata reservation because we might
4598                          * actually need it later on.
4599                          */
4600                         ext4_da_update_reserve_space(inode, allocated_clusters,
4601                                                         1);
4602                 }
4603         }
4604
4605         /*
4606          * Cache the extent and update transaction to commit on fdatasync only
4607          * when it is _not_ an unwritten extent.
4608          */
4609         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4610                 ext4_update_inode_fsync_trans(handle, inode, 1);
4611         else
4612                 ext4_update_inode_fsync_trans(handle, inode, 0);
4613 out:
4614         if (allocated > map->m_len)
4615                 allocated = map->m_len;
4616         ext4_ext_show_leaf(inode, path);
4617         map->m_flags |= EXT4_MAP_MAPPED;
4618         map->m_pblk = newblock;
4619         map->m_len = allocated;
4620 out2:
4621         if (path) {
4622                 ext4_ext_drop_refs(path);
4623                 kfree(path);
4624         }
4625
4626         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4627                                        err ? err : allocated);
4628         ext4_es_lru_add(inode);
4629         return err ? err : allocated;
4630 }
4631
4632 void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4633 {
4634         struct super_block *sb = inode->i_sb;
4635         ext4_lblk_t last_block;
4636         int err = 0;
4637
4638         /*
4639          * TODO: optimization is possible here.
4640          * Probably we need not scan at all,
4641          * because page truncation is enough.
4642          */
4643
4644         /* we have to know where to truncate from in crash case */
4645         EXT4_I(inode)->i_disksize = inode->i_size;
4646         ext4_mark_inode_dirty(handle, inode);
4647
4648         last_block = (inode->i_size + sb->s_blocksize - 1)
4649                         >> EXT4_BLOCK_SIZE_BITS(sb);
4650 retry:
4651         err = ext4_es_remove_extent(inode, last_block,
4652                                     EXT_MAX_BLOCKS - last_block);
4653         if (err == -ENOMEM) {
4654                 cond_resched();
4655                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4656                 goto retry;
4657         }
4658         if (err) {
4659                 ext4_std_error(inode->i_sb, err);
4660                 return;
4661         }
4662         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4663         ext4_std_error(inode->i_sb, err);
4664 }
4665
4666 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4667                                   ext4_lblk_t len, int flags, int mode)
4668 {
4669         struct inode *inode = file_inode(file);
4670         handle_t *handle;
4671         int ret = 0;
4672         int ret2 = 0;
4673         int retries = 0;
4674         struct ext4_map_blocks map;
4675         unsigned int credits;
4676
4677         map.m_lblk = offset;
4678         /*
4679          * Don't normalize the request if it can fit in one extent so
4680          * that it doesn't get unnecessarily split into multiple
4681          * extents.
4682          */
4683         if (len <= EXT_UNWRITTEN_MAX_LEN)
4684                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4685
4686         /*
4687          * credits to insert 1 extent into extent tree
4688          */
4689         credits = ext4_chunk_trans_blocks(inode, len);
4690
4691 retry:
4692         while (ret >= 0 && ret < len) {
4693                 map.m_lblk = map.m_lblk + ret;
4694                 map.m_len = len = len - ret;
4695                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4696                                             credits);
4697                 if (IS_ERR(handle)) {
4698                         ret = PTR_ERR(handle);
4699                         break;
4700                 }
4701                 ret = ext4_map_blocks(handle, inode, &map, flags);
4702                 if (ret <= 0) {
4703                         ext4_debug("inode #%lu: block %u: len %u: "
4704                                    "ext4_ext_map_blocks returned %d",
4705                                    inode->i_ino, map.m_lblk,
4706                                    map.m_len, ret);
4707                         ext4_mark_inode_dirty(handle, inode);
4708                         ret2 = ext4_journal_stop(handle);
4709                         break;
4710                 }
4711                 ret2 = ext4_journal_stop(handle);
4712                 if (ret2)
4713                         break;
4714         }
4715         if (ret == -ENOSPC &&
4716                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4717                 ret = 0;
4718                 goto retry;
4719         }
4720
4721         return ret > 0 ? ret2 : ret;
4722 }
4723
4724 static long ext4_zero_range(struct file *file, loff_t offset,
4725                             loff_t len, int mode)
4726 {
4727         struct inode *inode = file_inode(file);
4728         handle_t *handle = NULL;
4729         unsigned int max_blocks;
4730         loff_t new_size = 0;
4731         int ret = 0;
4732         int flags;
4733         int partial;
4734         loff_t start, end;
4735         ext4_lblk_t lblk;
4736         struct address_space *mapping = inode->i_mapping;
4737         unsigned int blkbits = inode->i_blkbits;
4738
4739         trace_ext4_zero_range(inode, offset, len, mode);
4740
4741         if (!S_ISREG(inode->i_mode))
4742                 return -EINVAL;
4743
4744         /* Call ext4_force_commit to flush all data in case of data=journal. */
4745         if (ext4_should_journal_data(inode)) {
4746                 ret = ext4_force_commit(inode->i_sb);
4747                 if (ret)
4748                         return ret;
4749         }
4750
4751         /*
4752          * Write out all dirty pages to avoid race conditions
4753          * Then release them.
4754          */
4755         if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4756                 ret = filemap_write_and_wait_range(mapping, offset,
4757                                                    offset + len - 1);
4758                 if (ret)
4759                         return ret;
4760         }
4761
4762         /*
4763          * Round up offset. This is not fallocate, we neet to zero out
4764          * blocks, so convert interior block aligned part of the range to
4765          * unwritten and possibly manually zero out unaligned parts of the
4766          * range.
4767          */
4768         start = round_up(offset, 1 << blkbits);
4769         end = round_down((offset + len), 1 << blkbits);
4770
4771         if (start < offset || end > offset + len)
4772                 return -EINVAL;
4773         partial = (offset + len) & ((1 << blkbits) - 1);
4774
4775         lblk = start >> blkbits;
4776         max_blocks = (end >> blkbits);
4777         if (max_blocks < lblk)
4778                 max_blocks = 0;
4779         else
4780                 max_blocks -= lblk;
4781
4782         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT |
4783                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN;
4784         if (mode & FALLOC_FL_KEEP_SIZE)
4785                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4786
4787         mutex_lock(&inode->i_mutex);
4788
4789         /*
4790          * Indirect files do not support unwritten extnets
4791          */
4792         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4793                 ret = -EOPNOTSUPP;
4794                 goto out_mutex;
4795         }
4796
4797         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4798              offset + len > i_size_read(inode)) {
4799                 new_size = offset + len;
4800                 ret = inode_newsize_ok(inode, new_size);
4801                 if (ret)
4802                         goto out_mutex;
4803                 /*
4804                  * If we have a partial block after EOF we have to allocate
4805                  * the entire block.
4806                  */
4807                 if (partial)
4808                         max_blocks += 1;
4809         }
4810
4811         if (max_blocks > 0) {
4812
4813                 /* Now release the pages and zero block aligned part of pages*/
4814                 truncate_pagecache_range(inode, start, end - 1);
4815
4816                 /* Wait all existing dio workers, newcomers will block on i_mutex */
4817                 ext4_inode_block_unlocked_dio(inode);
4818                 inode_dio_wait(inode);
4819
4820                 /*
4821                  * Remove entire range from the extent status tree.
4822                  */
4823                 ret = ext4_es_remove_extent(inode, lblk, max_blocks);
4824                 if (ret)
4825                         goto out_dio;
4826
4827                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, flags,
4828                                              mode);
4829                 if (ret)
4830                         goto out_dio;
4831         }
4832
4833         handle = ext4_journal_start(inode, EXT4_HT_MISC, 4);
4834         if (IS_ERR(handle)) {
4835                 ret = PTR_ERR(handle);
4836                 ext4_std_error(inode->i_sb, ret);
4837                 goto out_dio;
4838         }
4839
4840         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4841
4842         if (new_size) {
4843                 if (new_size > i_size_read(inode))
4844                         i_size_write(inode, new_size);
4845                 if (new_size > EXT4_I(inode)->i_disksize)
4846                         ext4_update_i_disksize(inode, new_size);
4847         } else {
4848                 /*
4849                 * Mark that we allocate beyond EOF so the subsequent truncate
4850                 * can proceed even if the new size is the same as i_size.
4851                 */
4852                 if ((offset + len) > i_size_read(inode))
4853                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4854         }
4855
4856         ext4_mark_inode_dirty(handle, inode);
4857
4858         /* Zero out partial block at the edges of the range */
4859         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4860
4861         if (file->f_flags & O_SYNC)
4862                 ext4_handle_sync(handle);
4863
4864         ext4_journal_stop(handle);
4865 out_dio:
4866         ext4_inode_resume_unlocked_dio(inode);
4867 out_mutex:
4868         mutex_unlock(&inode->i_mutex);
4869         return ret;
4870 }
4871
4872 /*
4873  * preallocate space for a file. This implements ext4's fallocate file
4874  * operation, which gets called from sys_fallocate system call.
4875  * For block-mapped files, posix_fallocate should fall back to the method
4876  * of writing zeroes to the required new blocks (the same behavior which is
4877  * expected for file systems which do not support fallocate() system call).
4878  */
4879 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4880 {
4881         struct inode *inode = file_inode(file);
4882         handle_t *handle;
4883         loff_t new_size = 0;
4884         unsigned int max_blocks;
4885         int ret = 0;
4886         int flags;
4887         ext4_lblk_t lblk;
4888         struct timespec tv;
4889         unsigned int blkbits = inode->i_blkbits;
4890
4891         /* Return error if mode is not supported */
4892         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4893                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
4894                 return -EOPNOTSUPP;
4895
4896         if (mode & FALLOC_FL_PUNCH_HOLE)
4897                 return ext4_punch_hole(inode, offset, len);
4898
4899         ret = ext4_convert_inline_data(inode);
4900         if (ret)
4901                 return ret;
4902
4903         /*
4904          * currently supporting (pre)allocate mode for extent-based
4905          * files _only_
4906          */
4907         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4908                 return -EOPNOTSUPP;
4909
4910         if (mode & FALLOC_FL_COLLAPSE_RANGE)
4911                 return ext4_collapse_range(inode, offset, len);
4912
4913         if (mode & FALLOC_FL_ZERO_RANGE)
4914                 return ext4_zero_range(file, offset, len, mode);
4915
4916         trace_ext4_fallocate_enter(inode, offset, len, mode);
4917         lblk = offset >> blkbits;
4918         /*
4919          * We can't just convert len to max_blocks because
4920          * If blocksize = 4096 offset = 3072 and len = 2048
4921          */
4922         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4923                 - lblk;
4924
4925         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4926         if (mode & FALLOC_FL_KEEP_SIZE)
4927                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4928
4929         mutex_lock(&inode->i_mutex);
4930
4931         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4932              offset + len > i_size_read(inode)) {
4933                 new_size = offset + len;
4934                 ret = inode_newsize_ok(inode, new_size);
4935                 if (ret)
4936                         goto out;
4937         }
4938
4939         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, flags, mode);
4940         if (ret)
4941                 goto out;
4942
4943         handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
4944         if (IS_ERR(handle))
4945                 goto out;
4946
4947         tv = inode->i_ctime = ext4_current_time(inode);
4948
4949         if (new_size) {
4950                 if (new_size > i_size_read(inode)) {
4951                         i_size_write(inode, new_size);
4952                         inode->i_mtime = tv;
4953                 }
4954                 if (new_size > EXT4_I(inode)->i_disksize)
4955                         ext4_update_i_disksize(inode, new_size);
4956         } else {
4957                 /*
4958                 * Mark that we allocate beyond EOF so the subsequent truncate
4959                 * can proceed even if the new size is the same as i_size.
4960                 */
4961                 if ((offset + len) > i_size_read(inode))
4962                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4963         }
4964         ext4_mark_inode_dirty(handle, inode);
4965         if (file->f_flags & O_SYNC)
4966                 ext4_handle_sync(handle);
4967
4968         ext4_journal_stop(handle);
4969 out:
4970         mutex_unlock(&inode->i_mutex);
4971         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4972         return ret;
4973 }
4974
4975 /*
4976  * This function convert a range of blocks to written extents
4977  * The caller of this function will pass the start offset and the size.
4978  * all unwritten extents within this range will be converted to
4979  * written extents.
4980  *
4981  * This function is called from the direct IO end io call back
4982  * function, to convert the fallocated extents after IO is completed.
4983  * Returns 0 on success.
4984  */
4985 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4986                                    loff_t offset, ssize_t len)
4987 {
4988         unsigned int max_blocks;
4989         int ret = 0;
4990         int ret2 = 0;
4991         struct ext4_map_blocks map;
4992         unsigned int credits, blkbits = inode->i_blkbits;
4993
4994         map.m_lblk = offset >> blkbits;
4995         /*
4996          * We can't just convert len to max_blocks because
4997          * If blocksize = 4096 offset = 3072 and len = 2048
4998          */
4999         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
5000                       map.m_lblk);
5001         /*
5002          * This is somewhat ugly but the idea is clear: When transaction is
5003          * reserved, everything goes into it. Otherwise we rather start several
5004          * smaller transactions for conversion of each extent separately.
5005          */
5006         if (handle) {
5007                 handle = ext4_journal_start_reserved(handle,
5008                                                      EXT4_HT_EXT_CONVERT);
5009                 if (IS_ERR(handle))
5010                         return PTR_ERR(handle);
5011                 credits = 0;
5012         } else {
5013                 /*
5014                  * credits to insert 1 extent into extent tree
5015                  */
5016                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5017         }
5018         while (ret >= 0 && ret < max_blocks) {
5019                 map.m_lblk += ret;
5020                 map.m_len = (max_blocks -= ret);
5021                 if (credits) {
5022                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5023                                                     credits);
5024                         if (IS_ERR(handle)) {
5025                                 ret = PTR_ERR(handle);
5026                                 break;
5027                         }
5028                 }
5029                 ret = ext4_map_blocks(handle, inode, &map,
5030                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5031                 if (ret <= 0)
5032                         ext4_warning(inode->i_sb,
5033                                      "inode #%lu: block %u: len %u: "
5034                                      "ext4_ext_map_blocks returned %d",
5035                                      inode->i_ino, map.m_lblk,
5036                                      map.m_len, ret);
5037                 ext4_mark_inode_dirty(handle, inode);
5038                 if (credits)
5039                         ret2 = ext4_journal_stop(handle);
5040                 if (ret <= 0 || ret2)
5041                         break;
5042         }
5043         if (!credits)
5044                 ret2 = ext4_journal_stop(handle);
5045         return ret > 0 ? ret2 : ret;
5046 }
5047
5048 /*
5049  * If newes is not existing extent (newes->ec_pblk equals zero) find
5050  * delayed extent at start of newes and update newes accordingly and
5051  * return start of the next delayed extent.
5052  *
5053  * If newes is existing extent (newes->ec_pblk is not equal zero)
5054  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5055  * extent found. Leave newes unmodified.
5056  */
5057 static int ext4_find_delayed_extent(struct inode *inode,
5058                                     struct extent_status *newes)
5059 {
5060         struct extent_status es;
5061         ext4_lblk_t block, next_del;
5062
5063         if (newes->es_pblk == 0) {
5064                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5065                                 newes->es_lblk + newes->es_len - 1, &es);
5066
5067                 /*
5068                  * No extent in extent-tree contains block @newes->es_pblk,
5069                  * then the block may stay in 1)a hole or 2)delayed-extent.
5070                  */
5071                 if (es.es_len == 0)
5072                         /* A hole found. */
5073                         return 0;
5074
5075                 if (es.es_lblk > newes->es_lblk) {
5076                         /* A hole found. */
5077                         newes->es_len = min(es.es_lblk - newes->es_lblk,
5078                                             newes->es_len);
5079                         return 0;
5080                 }
5081
5082                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5083         }
5084
5085         block = newes->es_lblk + newes->es_len;
5086         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5087         if (es.es_len == 0)
5088                 next_del = EXT_MAX_BLOCKS;
5089         else
5090                 next_del = es.es_lblk;
5091
5092         return next_del;
5093 }
5094 /* fiemap flags we can handle specified here */
5095 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5096
5097 static int ext4_xattr_fiemap(struct inode *inode,
5098                                 struct fiemap_extent_info *fieinfo)
5099 {
5100         __u64 physical = 0;
5101         __u64 length;
5102         __u32 flags = FIEMAP_EXTENT_LAST;
5103         int blockbits = inode->i_sb->s_blocksize_bits;
5104         int error = 0;
5105
5106         /* in-inode? */
5107         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5108                 struct ext4_iloc iloc;
5109                 int offset;     /* offset of xattr in inode */
5110
5111                 error = ext4_get_inode_loc(inode, &iloc);
5112                 if (error)
5113                         return error;
5114                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5115                 offset = EXT4_GOOD_OLD_INODE_SIZE +
5116                                 EXT4_I(inode)->i_extra_isize;
5117                 physical += offset;
5118                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5119                 flags |= FIEMAP_EXTENT_DATA_INLINE;
5120                 brelse(iloc.bh);
5121         } else { /* external block */
5122                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5123                 length = inode->i_sb->s_blocksize;
5124         }
5125
5126         if (physical)
5127                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5128                                                 length, flags);
5129         return (error < 0 ? error : 0);
5130 }
5131
5132 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5133                 __u64 start, __u64 len)
5134 {
5135         ext4_lblk_t start_blk;
5136         int error = 0;
5137
5138         if (ext4_has_inline_data(inode)) {
5139                 int has_inline = 1;
5140
5141                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline);
5142
5143                 if (has_inline)
5144                         return error;
5145         }
5146
5147         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5148                 error = ext4_ext_precache(inode);
5149                 if (error)
5150                         return error;
5151         }
5152
5153         /* fallback to generic here if not in extents fmt */
5154         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5155                 return generic_block_fiemap(inode, fieinfo, start, len,
5156                         ext4_get_block);
5157
5158         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5159                 return -EBADR;
5160
5161         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5162                 error = ext4_xattr_fiemap(inode, fieinfo);
5163         } else {
5164                 ext4_lblk_t len_blks;
5165                 __u64 last_blk;
5166
5167                 start_blk = start >> inode->i_sb->s_blocksize_bits;
5168                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5169                 if (last_blk >= EXT_MAX_BLOCKS)
5170                         last_blk = EXT_MAX_BLOCKS-1;
5171                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5172
5173                 /*
5174                  * Walk the extent tree gathering extent information
5175                  * and pushing extents back to the user.
5176                  */
5177                 error = ext4_fill_fiemap_extents(inode, start_blk,
5178                                                  len_blks, fieinfo);
5179         }
5180         ext4_es_lru_add(inode);
5181         return error;
5182 }
5183
5184 /*
5185  * ext4_access_path:
5186  * Function to access the path buffer for marking it dirty.
5187  * It also checks if there are sufficient credits left in the journal handle
5188  * to update path.
5189  */
5190 static int
5191 ext4_access_path(handle_t *handle, struct inode *inode,
5192                 struct ext4_ext_path *path)
5193 {
5194         int credits, err;
5195
5196         if (!ext4_handle_valid(handle))
5197                 return 0;
5198
5199         /*
5200          * Check if need to extend journal credits
5201          * 3 for leaf, sb, and inode plus 2 (bmap and group
5202          * descriptor) for each block group; assume two block
5203          * groups
5204          */
5205         if (handle->h_buffer_credits < 7) {
5206                 credits = ext4_writepage_trans_blocks(inode);
5207                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5208                 /* EAGAIN is success */
5209                 if (err && err != -EAGAIN)
5210                         return err;
5211         }
5212
5213         err = ext4_ext_get_access(handle, inode, path);
5214         return err;
5215 }
5216
5217 /*
5218  * ext4_ext_shift_path_extents:
5219  * Shift the extents of a path structure lying between path[depth].p_ext
5220  * and EXT_LAST_EXTENT(path[depth].p_hdr) downwards, by subtracting shift
5221  * from starting block for each extent.
5222  */
5223 static int
5224 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5225                             struct inode *inode, handle_t *handle,
5226                             ext4_lblk_t *start)
5227 {
5228         int depth, err = 0;
5229         struct ext4_extent *ex_start, *ex_last;
5230         bool update = 0;
5231         depth = path->p_depth;
5232
5233         while (depth >= 0) {
5234                 if (depth == path->p_depth) {
5235                         ex_start = path[depth].p_ext;
5236                         if (!ex_start)
5237                                 return -EIO;
5238
5239                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5240                         if (!ex_last)
5241                                 return -EIO;
5242
5243                         err = ext4_access_path(handle, inode, path + depth);
5244                         if (err)
5245                                 goto out;
5246
5247                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5248                                 update = 1;
5249
5250                         *start = le32_to_cpu(ex_last->ee_block) +
5251                                 ext4_ext_get_actual_len(ex_last);
5252
5253                         while (ex_start <= ex_last) {
5254                                 le32_add_cpu(&ex_start->ee_block, -shift);
5255                                 /* Try to merge to the left. */
5256                                 if ((ex_start >
5257                                      EXT_FIRST_EXTENT(path[depth].p_hdr)) &&
5258                                     ext4_ext_try_to_merge_right(inode,
5259                                                         path, ex_start - 1))
5260                                         ex_last--;
5261                                 else
5262                                         ex_start++;
5263                         }
5264                         err = ext4_ext_dirty(handle, inode, path + depth);
5265                         if (err)
5266                                 goto out;
5267
5268                         if (--depth < 0 || !update)
5269                                 break;
5270                 }
5271
5272                 /* Update index too */
5273                 err = ext4_access_path(handle, inode, path + depth);
5274                 if (err)
5275                         goto out;
5276
5277                 le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5278                 err = ext4_ext_dirty(handle, inode, path + depth);
5279                 if (err)
5280                         goto out;
5281
5282                 /* we are done if current index is not a starting index */
5283                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5284                         break;
5285
5286                 depth--;
5287         }
5288
5289 out:
5290         return err;
5291 }
5292
5293 /*
5294  * ext4_ext_shift_extents:
5295  * All the extents which lies in the range from start to the last allocated
5296  * block for the file are shifted downwards by shift blocks.
5297  * On success, 0 is returned, error otherwise.
5298  */
5299 static int
5300 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5301                        ext4_lblk_t start, ext4_lblk_t shift)
5302 {
5303         struct ext4_ext_path *path;
5304         int ret = 0, depth;
5305         struct ext4_extent *extent;
5306         ext4_lblk_t stop_block, current_block;
5307         ext4_lblk_t ex_start, ex_end;
5308
5309         /* Let path point to the last extent */
5310         path = ext4_ext_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
5311         if (IS_ERR(path))
5312                 return PTR_ERR(path);
5313
5314         depth = path->p_depth;
5315         extent = path[depth].p_ext;
5316         if (!extent) {
5317                 ext4_ext_drop_refs(path);
5318                 kfree(path);
5319                 return ret;
5320         }
5321
5322         stop_block = le32_to_cpu(extent->ee_block) +
5323                         ext4_ext_get_actual_len(extent);
5324         ext4_ext_drop_refs(path);
5325         kfree(path);
5326
5327         /* Nothing to shift, if hole is at the end of file */
5328         if (start >= stop_block)
5329                 return ret;
5330
5331         /*
5332          * Don't start shifting extents until we make sure the hole is big
5333          * enough to accomodate the shift.
5334          */
5335         path = ext4_ext_find_extent(inode, start - 1, NULL, 0);
5336         if (IS_ERR(path))
5337                 return PTR_ERR(path);
5338         depth = path->p_depth;
5339         extent =  path[depth].p_ext;
5340         if (extent) {
5341                 ex_start = le32_to_cpu(extent->ee_block);
5342                 ex_end = le32_to_cpu(extent->ee_block) +
5343                         ext4_ext_get_actual_len(extent);
5344         } else {
5345                 ex_start = 0;
5346                 ex_end = 0;
5347         }
5348         ext4_ext_drop_refs(path);
5349         kfree(path);
5350
5351         if ((start == ex_start && shift > ex_start) ||
5352             (shift > start - ex_end))
5353                 return -EINVAL;
5354
5355         /* Its safe to start updating extents */
5356         while (start < stop_block) {
5357                 path = ext4_ext_find_extent(inode, start, NULL, 0);
5358                 if (IS_ERR(path))
5359                         return PTR_ERR(path);
5360                 depth = path->p_depth;
5361                 extent = path[depth].p_ext;
5362                 if (!extent) {
5363                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5364                                          (unsigned long) start);
5365                         return -EIO;
5366                 }
5367
5368                 current_block = le32_to_cpu(extent->ee_block);
5369                 if (start > current_block) {
5370                         /* Hole, move to the next extent */
5371                         ret = mext_next_extent(inode, path, &extent);
5372                         if (ret != 0) {
5373                                 ext4_ext_drop_refs(path);
5374                                 kfree(path);
5375                                 if (ret == 1)
5376                                         ret = 0;
5377                                 break;
5378                         }
5379                 }
5380                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5381                                 handle, &start);
5382                 ext4_ext_drop_refs(path);
5383                 kfree(path);
5384                 if (ret)
5385                         break;
5386         }
5387
5388         return ret;
5389 }
5390
5391 /*
5392  * ext4_collapse_range:
5393  * This implements the fallocate's collapse range functionality for ext4
5394  * Returns: 0 and non-zero on error.
5395  */
5396 int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5397 {
5398         struct super_block *sb = inode->i_sb;
5399         ext4_lblk_t punch_start, punch_stop;
5400         handle_t *handle;
5401         unsigned int credits;
5402         loff_t new_size, ioffset;
5403         int ret;
5404
5405         /* Collapse range works only on fs block size aligned offsets. */
5406         if (offset & (EXT4_BLOCK_SIZE(sb) - 1) ||
5407             len & (EXT4_BLOCK_SIZE(sb) - 1))
5408                 return -EINVAL;
5409
5410         if (!S_ISREG(inode->i_mode))
5411                 return -EINVAL;
5412
5413         if (EXT4_SB(inode->i_sb)->s_cluster_ratio > 1)
5414                 return -EOPNOTSUPP;
5415
5416         trace_ext4_collapse_range(inode, offset, len);
5417
5418         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5419         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5420
5421         /* Call ext4_force_commit to flush all data in case of data=journal. */
5422         if (ext4_should_journal_data(inode)) {
5423                 ret = ext4_force_commit(inode->i_sb);
5424                 if (ret)
5425                         return ret;
5426         }
5427
5428         /*
5429          * Need to round down offset to be aligned with page size boundary
5430          * for page size > block size.
5431          */
5432         ioffset = round_down(offset, PAGE_SIZE);
5433
5434         /* Write out all dirty pages */
5435         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5436                                            LLONG_MAX);
5437         if (ret)
5438                 return ret;
5439
5440         /* Take mutex lock */
5441         mutex_lock(&inode->i_mutex);
5442
5443         /*
5444          * There is no need to overlap collapse range with EOF, in which case
5445          * it is effectively a truncate operation
5446          */
5447         if (offset + len >= i_size_read(inode)) {
5448                 ret = -EINVAL;
5449                 goto out_mutex;
5450         }
5451
5452         /* Currently just for extent based files */
5453         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5454                 ret = -EOPNOTSUPP;
5455                 goto out_mutex;
5456         }
5457
5458         truncate_pagecache(inode, ioffset);
5459
5460         /* Wait for existing dio to complete */
5461         ext4_inode_block_unlocked_dio(inode);
5462         inode_dio_wait(inode);
5463
5464         credits = ext4_writepage_trans_blocks(inode);
5465         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5466         if (IS_ERR(handle)) {
5467                 ret = PTR_ERR(handle);
5468                 goto out_dio;
5469         }
5470
5471         down_write(&EXT4_I(inode)->i_data_sem);
5472         ext4_discard_preallocations(inode);
5473
5474         ret = ext4_es_remove_extent(inode, punch_start,
5475                                     EXT_MAX_BLOCKS - punch_start);
5476         if (ret) {
5477                 up_write(&EXT4_I(inode)->i_data_sem);
5478                 goto out_stop;
5479         }
5480
5481         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5482         if (ret) {
5483                 up_write(&EXT4_I(inode)->i_data_sem);
5484                 goto out_stop;
5485         }
5486         ext4_discard_preallocations(inode);
5487
5488         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5489                                      punch_stop - punch_start);
5490         if (ret) {
5491                 up_write(&EXT4_I(inode)->i_data_sem);
5492                 goto out_stop;
5493         }
5494
5495         new_size = i_size_read(inode) - len;
5496         i_size_write(inode, new_size);
5497         EXT4_I(inode)->i_disksize = new_size;
5498
5499         up_write(&EXT4_I(inode)->i_data_sem);
5500         if (IS_SYNC(inode))
5501                 ext4_handle_sync(handle);
5502         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5503         ext4_mark_inode_dirty(handle, inode);
5504
5505 out_stop:
5506         ext4_journal_stop(handle);
5507 out_dio:
5508         ext4_inode_resume_unlocked_dio(inode);
5509 out_mutex:
5510         mutex_unlock(&inode->i_mutex);
5511         return ret;
5512 }