fs/ext4/extents.c

   1 /*
   2  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3  * Written by Alex Tomas <alex@clusterfs.com>
   4  *
   5  * Architecture independence:
   6  *   Copyright (c) 2005, Bull S.A.
   7  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21  */
  22
  23 /*
  24  * Extents support for EXT4
  25  *
  26  * TODO:
  27  *   - ext4*_error() should be used in some situations
  28  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29  *   - smart tree reduction
  30  */
  31
  32 #include <linux/fs.h>
  33 #include <linux/time.h>
  34 #include <linux/jbd2.h>
  35 #include <linux/highuid.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/quotaops.h>
  38 #include <linux/string.h>
  39 #include <linux/slab.h>
  40 #include <asm/uaccess.h>
  41 #include <linux/fiemap.h>
  42 #include <linux/backing-dev.h>
  43 #include "ext4_jbd2.h"
  44 #include "ext4_extents.h"
  45 #include "xattr.h"
  46
  47 #include <trace/events/ext4.h>
  48
  49 /*
  50  * used by extent splitting.
  51  */
  52 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  53                                         due to ENOSPC */
  54 #define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  55 #define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  56
  57 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  58 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  59
  60 static __le32 ext4_extent_block_csum(struct inode *inode,
  61                                      struct ext4_extent_header *eh)
  62 {
  63         struct ext4_inode_info *ei = EXT4_I(inode);
  64         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  65         __u32 csum;
  66
  67         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  68                            EXT4_EXTENT_TAIL_OFFSET(eh));
  69         return cpu_to_le32(csum);
  70 }
  71
  72 static int ext4_extent_block_csum_verify(struct inode *inode,
  73                                          struct ext4_extent_header *eh)
  74 {
  75         struct ext4_extent_tail *et;
  76
  77         if (!ext4_has_metadata_csum(inode->i_sb))
  78                 return 1;
  79
  80         et = find_ext4_extent_tail(eh);
  81         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  82                 return 0;
  83         return 1;
  84 }
  85
  86 static void ext4_extent_block_csum_set(struct inode *inode,
  87                                        struct ext4_extent_header *eh)
  88 {
  89         struct ext4_extent_tail *et;
  90
  91         if (!ext4_has_metadata_csum(inode->i_sb))
  92                 return;
  93
  94         et = find_ext4_extent_tail(eh);
  95         et->et_checksum = ext4_extent_block_csum(inode, eh);
  96 }
  97
  98 static int ext4_split_extent(handle_t *handle,
  99                                 struct inode *inode,
 100                                 struct ext4_ext_path **ppath,
 101                                 struct ext4_map_blocks *map,
 102                                 int split_flag,
 103                                 int flags);
 104
 105 static int ext4_split_extent_at(handle_t *handle,
 106                              struct inode *inode,
 107                              struct ext4_ext_path **ppath,
 108                              ext4_lblk_t split,
 109                              int split_flag,
 110                              int flags);
 111
 112 static int ext4_find_delayed_extent(struct inode *inode,
 113                                     struct extent_status *newes);
 114
 115 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 116                                             struct inode *inode,
 117                                             int needed)
 118 {
 119         int err;
 120
 121         if (!ext4_handle_valid(handle))
 122                 return 0;
 123         if (handle->h_buffer_credits >= needed)
 124                 return 0;
 125         /*
 126          * If we need to extend the journal get a few extra blocks
 127          * while we're at it for efficiency's sake.
 128          */
 129         needed += 3;
 130         err = ext4_journal_extend(handle, needed - handle->h_buffer_credits);
 131         if (err <= 0)
 132                 return err;
 133         err = ext4_truncate_restart_trans(handle, inode, needed);
 134         if (err == 0)
 135                 err = -EAGAIN;
 136
 137         return err;
 138 }
 139
 140 /*
 141  * could return:
 142  *  - EROFS
 143  *  - ENOMEM
 144  */
 145 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 146                                 struct ext4_ext_path *path)
 147 {
 148         if (path->p_bh) {
 149                 /* path points to block */
 150                 BUFFER_TRACE(path->p_bh, "get_write_access");
 151                 return ext4_journal_get_write_access(handle, path->p_bh);
 152         }
 153         /* path points to leaf/index in inode body */
 154         /* we use in-core data, no need to protect them */
 155         return 0;
 156 }
 157
 158 /*
 159  * could return:
 160  *  - EROFS
 161  *  - ENOMEM
 162  *  - EIO
 163  */
 164 int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 165                      struct inode *inode, struct ext4_ext_path *path)
 166 {
 167         int err;
 168
 169         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 170         if (path->p_bh) {
 171                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 172                 /* path points to block */
 173                 err = __ext4_handle_dirty_metadata(where, line, handle,
 174                                                    inode, path->p_bh);
 175         } else {
 176                 /* path points to leaf/index in inode body */
 177                 err = ext4_mark_inode_dirty(handle, inode);
 178         }
 179         return err;
 180 }
 181
 182 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 183                               struct ext4_ext_path *path,
 184                               ext4_lblk_t block)
 185 {
 186         if (path) {
 187                 int depth = path->p_depth;
 188                 struct ext4_extent *ex;
 189
 190                 /*
 191                  * Try to predict block placement assuming that we are
 192                  * filling in a file which will eventually be
 193                  * non-sparse --- i.e., in the case of libbfd writing
 194                  * an ELF object sections out-of-order but in a way
 195                  * the eventually results in a contiguous object or
 196                  * executable file, or some database extending a table
 197                  * space file.  However, this is actually somewhat
 198                  * non-ideal if we are writing a sparse file such as
 199                  * qemu or KVM writing a raw image file that is going
 200                  * to stay fairly sparse, since it will end up
 201                  * fragmenting the file system's free space.  Maybe we
 202                  * should have some hueristics or some way to allow
 203                  * userspace to pass a hint to file system,
 204                  * especially if the latter case turns out to be
 205                  * common.
 206                  */
 207                 ex = path[depth].p_ext;
 208                 if (ex) {
 209                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 210                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 211
 212                         if (block > ext_block)
 213                                 return ext_pblk + (block - ext_block);
 214                         else
 215                                 return ext_pblk - (ext_block - block);
 216                 }
 217
 218                 /* it looks like index is empty;
 219                  * try to find starting block from index itself */
 220                 if (path[depth].p_bh)
 221                         return path[depth].p_bh->b_blocknr;
 222         }
 223
 224         /* OK. use inode's group */
 225         return ext4_inode_to_goal_block(inode);
 226 }
 227
 228 /*
 229  * Allocation for a meta data block
 230  */
 231 static ext4_fsblk_t
 232 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 233                         struct ext4_ext_path *path,
 234                         struct ext4_extent *ex, int *err, unsigned int flags)
 235 {
 236         ext4_fsblk_t goal, newblock;
 237
 238         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 239         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 240                                         NULL, err);
 241         return newblock;
 242 }
 243
 244 static inline int ext4_ext_space_block(struct inode *inode, int check)
 245 {
 246         int size;
 247
 248         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 249                         / sizeof(struct ext4_extent);
 250 #ifdef AGGRESSIVE_TEST
 251         if (!check && size > 6)
 252                 size = 6;
 253 #endif
 254         return size;
 255 }
 256
 257 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 258 {
 259         int size;
 260
 261         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 262                         / sizeof(struct ext4_extent_idx);
 263 #ifdef AGGRESSIVE_TEST
 264         if (!check && size > 5)
 265                 size = 5;
 266 #endif
 267         return size;
 268 }
 269
 270 static inline int ext4_ext_space_root(struct inode *inode, int check)
 271 {
 272         int size;
 273
 274         size = sizeof(EXT4_I(inode)->i_data);
 275         size -= sizeof(struct ext4_extent_header);
 276         size /= sizeof(struct ext4_extent);
 277 #ifdef AGGRESSIVE_TEST
 278         if (!check && size > 3)
 279                 size = 3;
 280 #endif
 281         return size;
 282 }
 283
 284 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 285 {
 286         int size;
 287
 288         size = sizeof(EXT4_I(inode)->i_data);
 289         size -= sizeof(struct ext4_extent_header);
 290         size /= sizeof(struct ext4_extent_idx);
 291 #ifdef AGGRESSIVE_TEST
 292         if (!check && size > 4)
 293                 size = 4;
 294 #endif
 295         return size;
 296 }
 297
 298 static inline int
 299 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 300                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 301                            int nofail)
 302 {
 303         struct ext4_ext_path *path = *ppath;
 304         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 305
 306         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 307                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 308                         EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
 309                         (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
 310 }
 311
 312 /*
 313  * Calculate the number of metadata blocks needed
 314  * to allocate @blocks
 315  * Worse case is one block per extent
 316  */
 317 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 318 {
 319         struct ext4_inode_info *ei = EXT4_I(inode);
 320         int idxs;
 321
 322         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 323                 / sizeof(struct ext4_extent_idx));
 324
 325         /*
 326          * If the new delayed allocation block is contiguous with the
 327          * previous da block, it can share index blocks with the
 328          * previous block, so we only need to allocate a new index
 329          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 330          * an additional index block, and at ldxs**3 blocks, yet
 331          * another index blocks.
 332          */
 333         if (ei->i_da_metadata_calc_len &&
 334             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 335                 int num = 0;
 336
 337                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 338                         num++;
 339                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 340                         num++;
 341                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 342                         num++;
 343                         ei->i_da_metadata_calc_len = 0;
 344                 } else
 345                         ei->i_da_metadata_calc_len++;
 346                 ei->i_da_metadata_calc_last_lblock++;
 347                 return num;
 348         }
 349
 350         /*
 351          * In the worst case we need a new set of index blocks at
 352          * every level of the inode's extent tree.
 353          */
 354         ei->i_da_metadata_calc_len = 1;
 355         ei->i_da_metadata_calc_last_lblock = lblock;
 356         return ext_depth(inode) + 1;
 357 }
 358
 359 static int
 360 ext4_ext_max_entries(struct inode *inode, int depth)
 361 {
 362         int max;
 363
 364         if (depth == ext_depth(inode)) {
 365                 if (depth == 0)
 366                         max = ext4_ext_space_root(inode, 1);
 367                 else
 368                         max = ext4_ext_space_root_idx(inode, 1);
 369         } else {
 370                 if (depth == 0)
 371                         max = ext4_ext_space_block(inode, 1);
 372                 else
 373                         max = ext4_ext_space_block_idx(inode, 1);
 374         }
 375
 376         return max;
 377 }
 378
 379 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 380 {
 381         ext4_fsblk_t block = ext4_ext_pblock(ext);
 382         int len = ext4_ext_get_actual_len(ext);
 383         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 384
 385         /*
 386          * We allow neither:
 387          *  - zero length
 388          *  - overflow/wrap-around
 389          */
 390         if (lblock + len <= lblock)
 391                 return 0;
 392         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 393 }
 394
 395 static int ext4_valid_extent_idx(struct inode *inode,
 396                                 struct ext4_extent_idx *ext_idx)
 397 {
 398         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 399
 400         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 401 }
 402
 403 static int ext4_valid_extent_entries(struct inode *inode,
 404                                 struct ext4_extent_header *eh,
 405                                 int depth)
 406 {
 407         unsigned short entries;
 408         if (eh->eh_entries == 0)
 409                 return 1;
 410
 411         entries = le16_to_cpu(eh->eh_entries);
 412
 413         if (depth == 0) {
 414                 /* leaf entries */
 415                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 416                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 417                 ext4_fsblk_t pblock = 0;
 418                 ext4_lblk_t lblock = 0;
 419                 ext4_lblk_t prev = 0;
 420                 int len = 0;
 421                 while (entries) {
 422                         if (!ext4_valid_extent(inode, ext))
 423                                 return 0;
 424
 425                         /* Check for overlapping extents */
 426                         lblock = le32_to_cpu(ext->ee_block);
 427                         len = ext4_ext_get_actual_len(ext);
 428                         if ((lblock <= prev) && prev) {
 429                                 pblock = ext4_ext_pblock(ext);
 430                                 es->s_last_error_block = cpu_to_le64(pblock);
 431                                 return 0;
 432                         }
 433                         ext++;
 434                         entries--;
 435                         prev = lblock + len - 1;
 436                 }
 437         } else {
 438                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 439                 while (entries) {
 440                         if (!ext4_valid_extent_idx(inode, ext_idx))
 441                                 return 0;
 442                         ext_idx++;
 443                         entries--;
 444                 }
 445         }
 446         return 1;
 447 }
 448
 449 static int __ext4_ext_check(const char *function, unsigned int line,
 450                             struct inode *inode, struct ext4_extent_header *eh,
 451                             int depth, ext4_fsblk_t pblk)
 452 {
 453         const char *error_msg;
 454         int max = 0, err = -EFSCORRUPTED;
 455
 456         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 457                 error_msg = "invalid magic";
 458                 goto corrupted;
 459         }
 460         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 461                 error_msg = "unexpected eh_depth";
 462                 goto corrupted;
 463         }
 464         if (unlikely(eh->eh_max == 0)) {
 465                 error_msg = "invalid eh_max";
 466                 goto corrupted;
 467         }
 468         max = ext4_ext_max_entries(inode, depth);
 469         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 470                 error_msg = "too large eh_max";
 471                 goto corrupted;
 472         }
 473         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 474                 error_msg = "invalid eh_entries";
 475                 goto corrupted;
 476         }
 477         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 478                 error_msg = "invalid extent entries";
 479                 goto corrupted;
 480         }
 481         /* Verify checksum on non-root extent tree nodes */
 482         if (ext_depth(inode) != depth &&
 483             !ext4_extent_block_csum_verify(inode, eh)) {
 484                 error_msg = "extent tree corrupted";
 485                 err = -EFSBADCRC;
 486                 goto corrupted;
 487         }
 488         return 0;
 489
 490 corrupted:
 491         ext4_error_inode(inode, function, line, 0,
 492                          "pblk %llu bad header/extent: %s - magic %x, "
 493                          "entries %u, max %u(%u), depth %u(%u)",
 494                          (unsigned long long) pblk, error_msg,
 495                          le16_to_cpu(eh->eh_magic),
 496                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 497                          max, le16_to_cpu(eh->eh_depth), depth);
 498         return err;
 499 }
 500
 501 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 502         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 503
 504 int ext4_ext_check_inode(struct inode *inode)
 505 {
 506         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 507 }
 508
 509 static struct buffer_head *
 510 __read_extent_tree_block(const char *function, unsigned int line,
 511                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 512                          int flags)
 513 {
 514         struct buffer_head              *bh;
 515         int                             err;
 516
 517         bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
 518         if (unlikely(!bh))
 519                 return ERR_PTR(-ENOMEM);
 520
 521         if (!bh_uptodate_or_lock(bh)) {
 522                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 523                 err = bh_submit_read(bh);
 524                 if (err < 0)
 525                         goto errout;
 526         }
 527         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 528                 return bh;
 529         err = __ext4_ext_check(function, line, inode,
 530                                ext_block_hdr(bh), depth, pblk);
 531         if (err)
 532                 goto errout;
 533         set_buffer_verified(bh);
 534         /*
 535          * If this is a leaf block, cache all of its entries
 536          */
 537         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 538                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 539                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 540                 ext4_lblk_t prev = 0;
 541                 int i;
 542
 543                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 544                         unsigned int status = EXTENT_STATUS_WRITTEN;
 545                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 546                         int len = ext4_ext_get_actual_len(ex);
 547
 548                         if (prev && (prev != lblk))
 549                                 ext4_es_cache_extent(inode, prev,
 550                                                      lblk - prev, ~0,
 551                                                      EXTENT_STATUS_HOLE);
 552
 553                         if (ext4_ext_is_unwritten(ex))
 554                                 status = EXTENT_STATUS_UNWRITTEN;
 555                         ext4_es_cache_extent(inode, lblk, len,
 556                                              ext4_ext_pblock(ex), status);
 557                         prev = lblk + len;
 558                 }
 559         }
 560         return bh;
 561 errout:
 562         put_bh(bh);
 563         return ERR_PTR(err);
 564
 565 }
 566
 567 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 568         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 569                                  (depth), (flags))
 570
 571 /*
 572  * This function is called to cache a file's extent information in the
 573  * extent status tree
 574  */
 575 int ext4_ext_precache(struct inode *inode)
 576 {
 577         struct ext4_inode_info *ei = EXT4_I(inode);
 578         struct ext4_ext_path *path = NULL;
 579         struct buffer_head *bh;
 580         int i = 0, depth, ret = 0;
 581
 582         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 583                 return 0;       /* not an extent-mapped inode */
 584
 585         down_read(&ei->i_data_sem);
 586         depth = ext_depth(inode);
 587
 588         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 589                        GFP_NOFS);
 590         if (path == NULL) {
 591                 up_read(&ei->i_data_sem);
 592                 return -ENOMEM;
 593         }
 594
 595         /* Don't cache anything if there are no external extent blocks */
 596         if (depth == 0)
 597                 goto out;
 598         path[0].p_hdr = ext_inode_hdr(inode);
 599         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 600         if (ret)
 601                 goto out;
 602         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 603         while (i >= 0) {
 604                 /*
 605                  * If this is a leaf block or we've reached the end of
 606                  * the index block, go up
 607                  */
 608                 if ((i == depth) ||
 609                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 610                         brelse(path[i].p_bh);
 611                         path[i].p_bh = NULL;
 612                         i--;
 613                         continue;
 614                 }
 615                 bh = read_extent_tree_block(inode,
 616                                             ext4_idx_pblock(path[i].p_idx++),
 617                                             depth - i - 1,
 618                                             EXT4_EX_FORCE_CACHE);
 619                 if (IS_ERR(bh)) {
 620                         ret = PTR_ERR(bh);
 621                         break;
 622                 }
 623                 i++;
 624                 path[i].p_bh = bh;
 625                 path[i].p_hdr = ext_block_hdr(bh);
 626                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 627         }
 628         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 629 out:
 630         up_read(&ei->i_data_sem);
 631         ext4_ext_drop_refs(path);
 632         kfree(path);
 633         return ret;
 634 }
 635
 636 #ifdef EXT_DEBUG
 637 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 638 {
 639         int k, l = path->p_depth;
 640
 641         ext_debug("path:");
 642         for (k = 0; k <= l; k++, path++) {
 643                 if (path->p_idx) {
 644                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 645                             ext4_idx_pblock(path->p_idx));
 646                 } else if (path->p_ext) {
 647                         ext_debug("  %d:[%d]%d:%llu ",
 648                                   le32_to_cpu(path->p_ext->ee_block),
 649                                   ext4_ext_is_unwritten(path->p_ext),
 650                                   ext4_ext_get_actual_len(path->p_ext),
 651                                   ext4_ext_pblock(path->p_ext));
 652                 } else
 653                         ext_debug("  []");
 654         }
 655         ext_debug("\n");
 656 }
 657
 658 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 659 {
 660         int depth = ext_depth(inode);
 661         struct ext4_extent_header *eh;
 662         struct ext4_extent *ex;
 663         int i;
 664
 665         if (!path)
 666                 return;
 667
 668         eh = path[depth].p_hdr;
 669         ex = EXT_FIRST_EXTENT(eh);
 670
 671         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 672
 673         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 674                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 675                           ext4_ext_is_unwritten(ex),
 676                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 677         }
 678         ext_debug("\n");
 679 }
 680
 681 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 682                         ext4_fsblk_t newblock, int level)
 683 {
 684         int depth = ext_depth(inode);
 685         struct ext4_extent *ex;
 686
 687         if (depth != level) {
 688                 struct ext4_extent_idx *idx;
 689                 idx = path[level].p_idx;
 690                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 691                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 692                                         le32_to_cpu(idx->ei_block),
 693                                         ext4_idx_pblock(idx),
 694                                         newblock);
 695                         idx++;
 696                 }
 697
 698                 return;
 699         }
 700
 701         ex = path[depth].p_ext;
 702         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 703                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 704                                 le32_to_cpu(ex->ee_block),
 705                                 ext4_ext_pblock(ex),
 706                                 ext4_ext_is_unwritten(ex),
 707                                 ext4_ext_get_actual_len(ex),
 708                                 newblock);
 709                 ex++;
 710         }
 711 }
 712
 713 #else
 714 #define ext4_ext_show_path(inode, path)
 715 #define ext4_ext_show_leaf(inode, path)
 716 #define ext4_ext_show_move(inode, path, newblock, level)
 717 #endif
 718
 719 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 720 {
 721         int depth, i;
 722
 723         if (!path)
 724                 return;
 725         depth = path->p_depth;
 726         for (i = 0; i <= depth; i++, path++)
 727                 if (path->p_bh) {
 728                         brelse(path->p_bh);
 729                         path->p_bh = NULL;
 730                 }
 731 }
 732
 733 /*
 734  * ext4_ext_binsearch_idx:
 735  * binary search for the closest index of the given block
 736  * the header must be checked before calling this
 737  */
 738 static void
 739 ext4_ext_binsearch_idx(struct inode *inode,
 740                         struct ext4_ext_path *path, ext4_lblk_t block)
 741 {
 742         struct ext4_extent_header *eh = path->p_hdr;
 743         struct ext4_extent_idx *r, *l, *m;
 744
 745
 746         ext_debug("binsearch for %u(idx):  ", block);
 747
 748         l = EXT_FIRST_INDEX(eh) + 1;
 749         r = EXT_LAST_INDEX(eh);
 750         while (l <= r) {
 751                 m = l + (r - l) / 2;
 752                 if (block < le32_to_cpu(m->ei_block))
 753                         r = m - 1;
 754                 else
 755                         l = m + 1;
 756                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 757                                 m, le32_to_cpu(m->ei_block),
 758                                 r, le32_to_cpu(r->ei_block));
 759         }
 760
 761         path->p_idx = l - 1;
 762         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 763                   ext4_idx_pblock(path->p_idx));
 764
 765 #ifdef CHECK_BINSEARCH
 766         {
 767                 struct ext4_extent_idx *chix, *ix;
 768                 int k;
 769
 770                 chix = ix = EXT_FIRST_INDEX(eh);
 771                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 772                   if (k != 0 &&
 773                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 774                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 775                                        "first=0x%p\n", k,
 776                                        ix, EXT_FIRST_INDEX(eh));
 777                                 printk(KERN_DEBUG "%u <= %u\n",
 778                                        le32_to_cpu(ix->ei_block),
 779                                        le32_to_cpu(ix[-1].ei_block));
 780                         }
 781                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 782                                            <= le32_to_cpu(ix[-1].ei_block));
 783                         if (block < le32_to_cpu(ix->ei_block))
 784                                 break;
 785                         chix = ix;
 786                 }
 787                 BUG_ON(chix != path->p_idx);
 788         }
 789 #endif
 790
 791 }
 792
 793 /*
 794  * ext4_ext_binsearch:
 795  * binary search for closest extent of the given block
 796  * the header must be checked before calling this
 797  */
 798 static void
 799 ext4_ext_binsearch(struct inode *inode,
 800                 struct ext4_ext_path *path, ext4_lblk_t block)
 801 {
 802         struct ext4_extent_header *eh = path->p_hdr;
 803         struct ext4_extent *r, *l, *m;
 804
 805         if (eh->eh_entries == 0) {
 806                 /*
 807                  * this leaf is empty:
 808                  * we get such a leaf in split/add case
 809                  */
 810                 return;
 811         }
 812
 813         ext_debug("binsearch for %u:  ", block);
 814
 815         l = EXT_FIRST_EXTENT(eh) + 1;
 816         r = EXT_LAST_EXTENT(eh);
 817
 818         while (l <= r) {
 819                 m = l + (r - l) / 2;
 820                 if (block < le32_to_cpu(m->ee_block))
 821                         r = m - 1;
 822                 else
 823                         l = m + 1;
 824                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 825                                 m, le32_to_cpu(m->ee_block),
 826                                 r, le32_to_cpu(r->ee_block));
 827         }
 828
 829         path->p_ext = l - 1;
 830         ext_debug("  -> %d:%llu:[%d]%d ",
 831                         le32_to_cpu(path->p_ext->ee_block),
 832                         ext4_ext_pblock(path->p_ext),
 833                         ext4_ext_is_unwritten(path->p_ext),
 834                         ext4_ext_get_actual_len(path->p_ext));
 835
 836 #ifdef CHECK_BINSEARCH
 837         {
 838                 struct ext4_extent *chex, *ex;
 839                 int k;
 840
 841                 chex = ex = EXT_FIRST_EXTENT(eh);
 842                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 843                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 844                                           <= le32_to_cpu(ex[-1].ee_block));
 845                         if (block < le32_to_cpu(ex->ee_block))
 846                                 break;
 847                         chex = ex;
 848                 }
 849                 BUG_ON(chex != path->p_ext);
 850         }
 851 #endif
 852
 853 }
 854
 855 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 856 {
 857         struct ext4_extent_header *eh;
 858
 859         eh = ext_inode_hdr(inode);
 860         eh->eh_depth = 0;
 861         eh->eh_entries = 0;
 862         eh->eh_magic = EXT4_EXT_MAGIC;
 863         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 864         ext4_mark_inode_dirty(handle, inode);
 865         return 0;
 866 }
 867
 868 struct ext4_ext_path *
 869 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 870                  struct ext4_ext_path **orig_path, int flags)
 871 {
 872         struct ext4_extent_header *eh;
 873         struct buffer_head *bh;
 874         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 875         short int depth, i, ppos = 0;
 876         int ret;
 877
 878         eh = ext_inode_hdr(inode);
 879         depth = ext_depth(inode);
 880
 881         if (path) {
 882                 ext4_ext_drop_refs(path);
 883                 if (depth > path[0].p_maxdepth) {
 884                         kfree(path);
 885                         *orig_path = path = NULL;
 886                 }
 887         }
 888         if (!path) {
 889                 /* account possible depth increase */
 890                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 891                                 GFP_NOFS);
 892                 if (unlikely(!path))
 893                         return ERR_PTR(-ENOMEM);
 894                 path[0].p_maxdepth = depth + 1;
 895         }
 896         path[0].p_hdr = eh;
 897         path[0].p_bh = NULL;
 898
 899         i = depth;
 900         /* walk through the tree */
 901         while (i) {
 902                 ext_debug("depth %d: num %d, max %d\n",
 903                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 904
 905                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 906                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 907                 path[ppos].p_depth = i;
 908                 path[ppos].p_ext = NULL;
 909
 910                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 911                                             flags);
 912                 if (IS_ERR(bh)) {
 913                         ret = PTR_ERR(bh);
 914                         goto err;
 915                 }
 916
 917                 eh = ext_block_hdr(bh);
 918                 ppos++;
 919                 path[ppos].p_bh = bh;
 920                 path[ppos].p_hdr = eh;
 921         }
 922
 923         path[ppos].p_depth = i;
 924         path[ppos].p_ext = NULL;
 925         path[ppos].p_idx = NULL;
 926
 927         /* find extent */
 928         ext4_ext_binsearch(inode, path + ppos, block);
 929         /* if not an empty leaf */
 930         if (path[ppos].p_ext)
 931                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 932
 933         ext4_ext_show_path(inode, path);
 934
 935         return path;
 936
 937 err:
 938         ext4_ext_drop_refs(path);
 939         kfree(path);
 940         if (orig_path)
 941                 *orig_path = NULL;
 942         return ERR_PTR(ret);
 943 }
 944
 945 /*
 946  * ext4_ext_insert_index:
 947  * insert new index [@logical;@ptr] into the block at @curp;
 948  * check where to insert: before @curp or after @curp
 949  */
 950 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 951                                  struct ext4_ext_path *curp,
 952                                  int logical, ext4_fsblk_t ptr)
 953 {
 954         struct ext4_extent_idx *ix;
 955         int len, err;
 956
 957         err = ext4_ext_get_access(handle, inode, curp);
 958         if (err)
 959                 return err;
 960
 961         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 962                 EXT4_ERROR_INODE(inode,
 963                                  "logical %d == ei_block %d!",
 964                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 965                 return -EFSCORRUPTED;
 966         }
 967
 968         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 969                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 970                 EXT4_ERROR_INODE(inode,
 971                                  "eh_entries %d >= eh_max %d!",
 972                                  le16_to_cpu(curp->p_hdr->eh_entries),
 973                                  le16_to_cpu(curp->p_hdr->eh_max));
 974                 return -EFSCORRUPTED;
 975         }
 976
 977         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 978                 /* insert after */
 979                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 980                 ix = curp->p_idx + 1;
 981         } else {
 982                 /* insert before */
 983                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 984                 ix = curp->p_idx;
 985         }
 986
 987         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 988         BUG_ON(len < 0);
 989         if (len > 0) {
 990                 ext_debug("insert new index %d: "
 991                                 "move %d indices from 0x%p to 0x%p\n",
 992                                 logical, len, ix, ix + 1);
 993                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 994         }
 995
 996         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 997                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 998                 return -EFSCORRUPTED;
 999         }
1000
1001         ix->ei_block = cpu_to_le32(logical);
1002         ext4_idx_store_pblock(ix, ptr);
1003         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1004
1005         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1006                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1007                 return -EFSCORRUPTED;
1008         }
1009
1010         err = ext4_ext_dirty(handle, inode, curp);
1011         ext4_std_error(inode->i_sb, err);
1012
1013         return err;
1014 }
1015
1016 /*
1017  * ext4_ext_split:
1018  * inserts new subtree into the path, using free index entry
1019  * at depth @at:
1020  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1021  * - makes decision where to split
1022  * - moves remaining extents and index entries (right to the split point)
1023  *   into the newly allocated blocks
1024  * - initializes subtree
1025  */
1026 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1027                           unsigned int flags,
1028                           struct ext4_ext_path *path,
1029                           struct ext4_extent *newext, int at)
1030 {
1031         struct buffer_head *bh = NULL;
1032         int depth = ext_depth(inode);
1033         struct ext4_extent_header *neh;
1034         struct ext4_extent_idx *fidx;
1035         int i = at, k, m, a;
1036         ext4_fsblk_t newblock, oldblock;
1037         __le32 border;
1038         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1039         int err = 0;
1040
1041         /* make decision: where to split? */
1042         /* FIXME: now decision is simplest: at current extent */
1043
1044         /* if current leaf will be split, then we should use
1045          * border from split point */
1046         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1047                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1048                 return -EFSCORRUPTED;
1049         }
1050         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1051                 border = path[depth].p_ext[1].ee_block;
1052                 ext_debug("leaf will be split."
1053                                 " next leaf starts at %d\n",
1054                                   le32_to_cpu(border));
1055         } else {
1056                 border = newext->ee_block;
1057                 ext_debug("leaf will be added."
1058                                 " next leaf starts at %d\n",
1059                                 le32_to_cpu(border));
1060         }
1061
1062         /*
1063          * If error occurs, then we break processing
1064          * and mark filesystem read-only. index won't
1065          * be inserted and tree will be in consistent
1066          * state. Next mount will repair buffers too.
1067          */
1068
1069         /*
1070          * Get array to track all allocated blocks.
1071          * We need this to handle errors and free blocks
1072          * upon them.
1073          */
1074         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1075         if (!ablocks)
1076                 return -ENOMEM;
1077
1078         /* allocate all needed blocks */
1079         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1080         for (a = 0; a < depth - at; a++) {
1081                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1082                                                    newext, &err, flags);
1083                 if (newblock == 0)
1084                         goto cleanup;
1085                 ablocks[a] = newblock;
1086         }
1087
1088         /* initialize new leaf */
1089         newblock = ablocks[--a];
1090         if (unlikely(newblock == 0)) {
1091                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1092                 err = -EFSCORRUPTED;
1093                 goto cleanup;
1094         }
1095         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1096         if (unlikely(!bh)) {
1097                 err = -ENOMEM;
1098                 goto cleanup;
1099         }
1100         lock_buffer(bh);
1101
1102         err = ext4_journal_get_create_access(handle, bh);
1103         if (err)
1104                 goto cleanup;
1105
1106         neh = ext_block_hdr(bh);
1107         neh->eh_entries = 0;
1108         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1109         neh->eh_magic = EXT4_EXT_MAGIC;
1110         neh->eh_depth = 0;
1111
1112         /* move remainder of path[depth] to the new leaf */
1113         if (unlikely(path[depth].p_hdr->eh_entries !=
1114                      path[depth].p_hdr->eh_max)) {
1115                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1116                                  path[depth].p_hdr->eh_entries,
1117                                  path[depth].p_hdr->eh_max);
1118                 err = -EFSCORRUPTED;
1119                 goto cleanup;
1120         }
1121         /* start copy from next extent */
1122         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1123         ext4_ext_show_move(inode, path, newblock, depth);
1124         if (m) {
1125                 struct ext4_extent *ex;
1126                 ex = EXT_FIRST_EXTENT(neh);
1127                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1128                 le16_add_cpu(&neh->eh_entries, m);
1129         }
1130
1131         ext4_extent_block_csum_set(inode, neh);
1132         set_buffer_uptodate(bh);
1133         unlock_buffer(bh);
1134
1135         err = ext4_handle_dirty_metadata(handle, inode, bh);
1136         if (err)
1137                 goto cleanup;
1138         brelse(bh);
1139         bh = NULL;
1140
1141         /* correct old leaf */
1142         if (m) {
1143                 err = ext4_ext_get_access(handle, inode, path + depth);
1144                 if (err)
1145                         goto cleanup;
1146                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1147                 err = ext4_ext_dirty(handle, inode, path + depth);
1148                 if (err)
1149                         goto cleanup;
1150
1151         }
1152
1153         /* create intermediate indexes */
1154         k = depth - at - 1;
1155         if (unlikely(k < 0)) {
1156                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1157                 err = -EFSCORRUPTED;
1158                 goto cleanup;
1159         }
1160         if (k)
1161                 ext_debug("create %d intermediate indices\n", k);
1162         /* insert new index into current index block */
1163         /* current depth stored in i var */
1164         i = depth - 1;
1165         while (k--) {
1166                 oldblock = newblock;
1167                 newblock = ablocks[--a];
1168                 bh = sb_getblk(inode->i_sb, newblock);
1169                 if (unlikely(!bh)) {
1170                         err = -ENOMEM;
1171                         goto cleanup;
1172                 }
1173                 lock_buffer(bh);
1174
1175                 err = ext4_journal_get_create_access(handle, bh);
1176                 if (err)
1177                         goto cleanup;
1178
1179                 neh = ext_block_hdr(bh);
1180                 neh->eh_entries = cpu_to_le16(1);
1181                 neh->eh_magic = EXT4_EXT_MAGIC;
1182                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1183                 neh->eh_depth = cpu_to_le16(depth - i);
1184                 fidx = EXT_FIRST_INDEX(neh);
1185                 fidx->ei_block = border;
1186                 ext4_idx_store_pblock(fidx, oldblock);
1187
1188                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1189                                 i, newblock, le32_to_cpu(border), oldblock);
1190
1191                 /* move remainder of path[i] to the new index block */
1192                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1193                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1194                         EXT4_ERROR_INODE(inode,
1195                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1196                                          le32_to_cpu(path[i].p_ext->ee_block));
1197                         err = -EFSCORRUPTED;
1198                         goto cleanup;
1199                 }
1200                 /* start copy indexes */
1201                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1202                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1203                                 EXT_MAX_INDEX(path[i].p_hdr));
1204                 ext4_ext_show_move(inode, path, newblock, i);
1205                 if (m) {
1206                         memmove(++fidx, path[i].p_idx,
1207                                 sizeof(struct ext4_extent_idx) * m);
1208                         le16_add_cpu(&neh->eh_entries, m);
1209                 }
1210                 ext4_extent_block_csum_set(inode, neh);
1211                 set_buffer_uptodate(bh);
1212                 unlock_buffer(bh);
1213
1214                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1215                 if (err)
1216                         goto cleanup;
1217                 brelse(bh);
1218                 bh = NULL;
1219
1220                 /* correct old index */
1221                 if (m) {
1222                         err = ext4_ext_get_access(handle, inode, path + i);
1223                         if (err)
1224                                 goto cleanup;
1225                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1226                         err = ext4_ext_dirty(handle, inode, path + i);
1227                         if (err)
1228                                 goto cleanup;
1229                 }
1230
1231                 i--;
1232         }
1233
1234         /* insert new index */
1235         err = ext4_ext_insert_index(handle, inode, path + at,
1236                                     le32_to_cpu(border), newblock);
1237
1238 cleanup:
1239         if (bh) {
1240                 if (buffer_locked(bh))
1241                         unlock_buffer(bh);
1242                 brelse(bh);
1243         }
1244
1245         if (err) {
1246                 /* free all allocated blocks in error case */
1247                 for (i = 0; i < depth; i++) {
1248                         if (!ablocks[i])
1249                                 continue;
1250                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1251                                          EXT4_FREE_BLOCKS_METADATA);
1252                 }
1253         }
1254         kfree(ablocks);
1255
1256         return err;
1257 }
1258
1259 /*
1260  * ext4_ext_grow_indepth:
1261  * implements tree growing procedure:
1262  * - allocates new block
1263  * - moves top-level data (index block or leaf) into the new block
1264  * - initializes new top-level, creating index that points to the
1265  *   just created block
1266  */
1267 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1268                                  unsigned int flags)
1269 {
1270         struct ext4_extent_header *neh;
1271         struct buffer_head *bh;
1272         ext4_fsblk_t newblock, goal = 0;
1273         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1274         int err = 0;
1275
1276         /* Try to prepend new index to old one */
1277         if (ext_depth(inode))
1278                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1279         if (goal > le32_to_cpu(es->s_first_data_block)) {
1280                 flags |= EXT4_MB_HINT_TRY_GOAL;
1281                 goal--;
1282         } else
1283                 goal = ext4_inode_to_goal_block(inode);
1284         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1285                                         NULL, &err);
1286         if (newblock == 0)
1287                 return err;
1288
1289         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1290         if (unlikely(!bh))
1291                 return -ENOMEM;
1292         lock_buffer(bh);
1293
1294         err = ext4_journal_get_create_access(handle, bh);
1295         if (err) {
1296                 unlock_buffer(bh);
1297                 goto out;
1298         }
1299
1300         /* move top-level index/leaf into new block */
1301         memmove(bh->b_data, EXT4_I(inode)->i_data,
1302                 sizeof(EXT4_I(inode)->i_data));
1303
1304         /* set size of new block */
1305         neh = ext_block_hdr(bh);
1306         /* old root could have indexes or leaves
1307          * so calculate e_max right way */
1308         if (ext_depth(inode))
1309                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1310         else
1311                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1312         neh->eh_magic = EXT4_EXT_MAGIC;
1313         ext4_extent_block_csum_set(inode, neh);
1314         set_buffer_uptodate(bh);
1315         unlock_buffer(bh);
1316
1317         err = ext4_handle_dirty_metadata(handle, inode, bh);
1318         if (err)
1319                 goto out;
1320
1321         /* Update top-level index: num,max,pointer */
1322         neh = ext_inode_hdr(inode);
1323         neh->eh_entries = cpu_to_le16(1);
1324         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1325         if (neh->eh_depth == 0) {
1326                 /* Root extent block becomes index block */
1327                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1328                 EXT_FIRST_INDEX(neh)->ei_block =
1329                         EXT_FIRST_EXTENT(neh)->ee_block;
1330         }
1331         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1332                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1333                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1334                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1335
1336         le16_add_cpu(&neh->eh_depth, 1);
1337         ext4_mark_inode_dirty(handle, inode);
1338 out:
1339         brelse(bh);
1340
1341         return err;
1342 }
1343
1344 /*
1345  * ext4_ext_create_new_leaf:
1346  * finds empty index and adds new leaf.
1347  * if no free index is found, then it requests in-depth growing.
1348  */
1349 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1350                                     unsigned int mb_flags,
1351                                     unsigned int gb_flags,
1352                                     struct ext4_ext_path **ppath,
1353                                     struct ext4_extent *newext)
1354 {
1355         struct ext4_ext_path *path = *ppath;
1356         struct ext4_ext_path *curp;
1357         int depth, i, err = 0;
1358
1359 repeat:
1360         i = depth = ext_depth(inode);
1361
1362         /* walk up to the tree and look for free index entry */
1363         curp = path + depth;
1364         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1365                 i--;
1366                 curp--;
1367         }
1368
1369         /* we use already allocated block for index block,
1370          * so subsequent data blocks should be contiguous */
1371         if (EXT_HAS_FREE_INDEX(curp)) {
1372                 /* if we found index with free entry, then use that
1373                  * entry: create all needed subtree and add new leaf */
1374                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1375                 if (err)
1376                         goto out;
1377
1378                 /* refill path */
1379                 path = ext4_find_extent(inode,
1380                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1381                                     ppath, gb_flags);
1382                 if (IS_ERR(path))
1383                         err = PTR_ERR(path);
1384         } else {
1385                 /* tree is full, time to grow in depth */
1386                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1387                 if (err)
1388                         goto out;
1389
1390                 /* refill path */
1391                 path = ext4_find_extent(inode,
1392                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1393                                     ppath, gb_flags);
1394                 if (IS_ERR(path)) {
1395                         err = PTR_ERR(path);
1396                         goto out;
1397                 }
1398
1399                 /*
1400                  * only first (depth 0 -> 1) produces free space;
1401                  * in all other cases we have to split the grown tree
1402                  */
1403                 depth = ext_depth(inode);
1404                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1405                         /* now we need to split */
1406                         goto repeat;
1407                 }
1408         }
1409
1410 out:
1411         return err;
1412 }
1413
1414 /*
1415  * search the closest allocated block to the left for *logical
1416  * and returns it at @logical + it's physical address at @phys
1417  * if *logical is the smallest allocated block, the function
1418  * returns 0 at @phys
1419  * return value contains 0 (success) or error code
1420  */
1421 static int ext4_ext_search_left(struct inode *inode,
1422                                 struct ext4_ext_path *path,
1423                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1424 {
1425         struct ext4_extent_idx *ix;
1426         struct ext4_extent *ex;
1427         int depth, ee_len;
1428
1429         if (unlikely(path == NULL)) {
1430                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1431                 return -EFSCORRUPTED;
1432         }
1433         depth = path->p_depth;
1434         *phys = 0;
1435
1436         if (depth == 0 && path->p_ext == NULL)
1437                 return 0;
1438
1439         /* usually extent in the path covers blocks smaller
1440          * then *logical, but it can be that extent is the
1441          * first one in the file */
1442
1443         ex = path[depth].p_ext;
1444         ee_len = ext4_ext_get_actual_len(ex);
1445         if (*logical < le32_to_cpu(ex->ee_block)) {
1446                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1447                         EXT4_ERROR_INODE(inode,
1448                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1449                                          *logical, le32_to_cpu(ex->ee_block));
1450                         return -EFSCORRUPTED;
1451                 }
1452                 while (--depth >= 0) {
1453                         ix = path[depth].p_idx;
1454                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1455                                 EXT4_ERROR_INODE(inode,
1456                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1457                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1458                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1459                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1460                                   depth);
1461                                 return -EFSCORRUPTED;
1462                         }
1463                 }
1464                 return 0;
1465         }
1466
1467         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1468                 EXT4_ERROR_INODE(inode,
1469                                  "logical %d < ee_block %d + ee_len %d!",
1470                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1471                 return -EFSCORRUPTED;
1472         }
1473
1474         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1475         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1476         return 0;
1477 }
1478
1479 /*
1480  * search the closest allocated block to the right for *logical
1481  * and returns it at @logical + it's physical address at @phys
1482  * if *logical is the largest allocated block, the function
1483  * returns 0 at @phys
1484  * return value contains 0 (success) or error code
1485  */
1486 static int ext4_ext_search_right(struct inode *inode,
1487                                  struct ext4_ext_path *path,
1488                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1489                                  struct ext4_extent **ret_ex)
1490 {
1491         struct buffer_head *bh = NULL;
1492         struct ext4_extent_header *eh;
1493         struct ext4_extent_idx *ix;
1494         struct ext4_extent *ex;
1495         ext4_fsblk_t block;
1496         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1497         int ee_len;
1498
1499         if (unlikely(path == NULL)) {
1500                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1501                 return -EFSCORRUPTED;
1502         }
1503         depth = path->p_depth;
1504         *phys = 0;
1505
1506         if (depth == 0 && path->p_ext == NULL)
1507                 return 0;
1508
1509         /* usually extent in the path covers blocks smaller
1510          * then *logical, but it can be that extent is the
1511          * first one in the file */
1512
1513         ex = path[depth].p_ext;
1514         ee_len = ext4_ext_get_actual_len(ex);
1515         if (*logical < le32_to_cpu(ex->ee_block)) {
1516                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1517                         EXT4_ERROR_INODE(inode,
1518                                          "first_extent(path[%d].p_hdr) != ex",
1519                                          depth);
1520                         return -EFSCORRUPTED;
1521                 }
1522                 while (--depth >= 0) {
1523                         ix = path[depth].p_idx;
1524                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1525                                 EXT4_ERROR_INODE(inode,
1526                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1527                                                  *logical);
1528                                 return -EFSCORRUPTED;
1529                         }
1530                 }
1531                 goto found_extent;
1532         }
1533
1534         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1535                 EXT4_ERROR_INODE(inode,
1536                                  "logical %d < ee_block %d + ee_len %d!",
1537                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1538                 return -EFSCORRUPTED;
1539         }
1540
1541         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1542                 /* next allocated block in this leaf */
1543                 ex++;
1544                 goto found_extent;
1545         }
1546
1547         /* go up and search for index to the right */
1548         while (--depth >= 0) {
1549                 ix = path[depth].p_idx;
1550                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1551                         goto got_index;
1552         }
1553
1554         /* we've gone up to the root and found no index to the right */
1555         return 0;
1556
1557 got_index:
1558         /* we've found index to the right, let's
1559          * follow it and find the closest allocated
1560          * block to the right */
1561         ix++;
1562         block = ext4_idx_pblock(ix);
1563         while (++depth < path->p_depth) {
1564                 /* subtract from p_depth to get proper eh_depth */
1565                 bh = read_extent_tree_block(inode, block,
1566                                             path->p_depth - depth, 0);
1567                 if (IS_ERR(bh))
1568                         return PTR_ERR(bh);
1569                 eh = ext_block_hdr(bh);
1570                 ix = EXT_FIRST_INDEX(eh);
1571                 block = ext4_idx_pblock(ix);
1572                 put_bh(bh);
1573         }
1574
1575         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1576         if (IS_ERR(bh))
1577                 return PTR_ERR(bh);
1578         eh = ext_block_hdr(bh);
1579         ex = EXT_FIRST_EXTENT(eh);
1580 found_extent:
1581         *logical = le32_to_cpu(ex->ee_block);
1582         *phys = ext4_ext_pblock(ex);
1583         *ret_ex = ex;
1584         if (bh)
1585                 put_bh(bh);
1586         return 0;
1587 }
1588
1589 /*
1590  * ext4_ext_next_allocated_block:
1591  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1592  * NOTE: it considers block number from index entry as
1593  * allocated block. Thus, index entries have to be consistent
1594  * with leaves.
1595  */
1596 ext4_lblk_t
1597 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1598 {
1599         int depth;
1600
1601         BUG_ON(path == NULL);
1602         depth = path->p_depth;
1603
1604         if (depth == 0 && path->p_ext == NULL)
1605                 return EXT_MAX_BLOCKS;
1606
1607         while (depth >= 0) {
1608                 if (depth == path->p_depth) {
1609                         /* leaf */
1610                         if (path[depth].p_ext &&
1611                                 path[depth].p_ext !=
1612                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1613                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1614                 } else {
1615                         /* index */
1616                         if (path[depth].p_idx !=
1617                                         EXT_LAST_INDEX(path[depth].p_hdr))
1618                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1619                 }
1620                 depth--;
1621         }
1622
1623         return EXT_MAX_BLOCKS;
1624 }
1625
1626 /*
1627  * ext4_ext_next_leaf_block:
1628  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1629  */
1630 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1631 {
1632         int depth;
1633
1634         BUG_ON(path == NULL);
1635         depth = path->p_depth;
1636
1637         /* zero-tree has no leaf blocks at all */
1638         if (depth == 0)
1639                 return EXT_MAX_BLOCKS;
1640
1641         /* go to index block */
1642         depth--;
1643
1644         while (depth >= 0) {
1645                 if (path[depth].p_idx !=
1646                                 EXT_LAST_INDEX(path[depth].p_hdr))
1647                         return (ext4_lblk_t)
1648                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1649                 depth--;
1650         }
1651
1652         return EXT_MAX_BLOCKS;
1653 }
1654
1655 /*
1656  * ext4_ext_correct_indexes:
1657  * if leaf gets modified and modified extent is first in the leaf,
1658  * then we have to correct all indexes above.
1659  * TODO: do we need to correct tree in all cases?
1660  */
1661 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1662                                 struct ext4_ext_path *path)
1663 {
1664         struct ext4_extent_header *eh;
1665         int depth = ext_depth(inode);
1666         struct ext4_extent *ex;
1667         __le32 border;
1668         int k, err = 0;
1669
1670         eh = path[depth].p_hdr;
1671         ex = path[depth].p_ext;
1672
1673         if (unlikely(ex == NULL || eh == NULL)) {
1674                 EXT4_ERROR_INODE(inode,
1675                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1676                 return -EFSCORRUPTED;
1677         }
1678
1679         if (depth == 0) {
1680                 /* there is no tree at all */
1681                 return 0;
1682         }
1683
1684         if (ex != EXT_FIRST_EXTENT(eh)) {
1685                 /* we correct tree if first leaf got modified only */
1686                 return 0;
1687         }
1688
1689         /*
1690          * TODO: we need correction if border is smaller than current one
1691          */
1692         k = depth - 1;
1693         border = path[depth].p_ext->ee_block;
1694         err = ext4_ext_get_access(handle, inode, path + k);
1695         if (err)
1696                 return err;
1697         path[k].p_idx->ei_block = border;
1698         err = ext4_ext_dirty(handle, inode, path + k);
1699         if (err)
1700                 return err;
1701
1702         while (k--) {
1703                 /* change all left-side indexes */
1704                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1705                         break;
1706                 err = ext4_ext_get_access(handle, inode, path + k);
1707                 if (err)
1708                         break;
1709                 path[k].p_idx->ei_block = border;
1710                 err = ext4_ext_dirty(handle, inode, path + k);
1711                 if (err)
1712                         break;
1713         }
1714
1715         return err;
1716 }
1717
1718 int
1719 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1720                                 struct ext4_extent *ex2)
1721 {
1722         unsigned short ext1_ee_len, ext2_ee_len;
1723
1724         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1725                 return 0;
1726
1727         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1728         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1729
1730         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1731                         le32_to_cpu(ex2->ee_block))
1732                 return 0;
1733
1734         /*
1735          * To allow future support for preallocated extents to be added
1736          * as an RO_COMPAT feature, refuse to merge to extents if
1737          * this can result in the top bit of ee_len being set.
1738          */
1739         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1740                 return 0;
1741         /*
1742          * The check for IO to unwritten extent is somewhat racy as we
1743          * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after
1744          * dropping i_data_sem. But reserved blocks should save us in that
1745          * case.
1746          */
1747         if (ext4_ext_is_unwritten(ex1) &&
1748             (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1749              atomic_read(&EXT4_I(inode)->i_unwritten) ||
1750              (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1751                 return 0;
1752 #ifdef AGGRESSIVE_TEST
1753         if (ext1_ee_len >= 4)
1754                 return 0;
1755 #endif
1756
1757         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1758                 return 1;
1759         return 0;
1760 }
1761
1762 /*
1763  * This function tries to merge the "ex" extent to the next extent in the tree.
1764  * It always tries to merge towards right. If you want to merge towards
1765  * left, pass "ex - 1" as argument instead of "ex".
1766  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1767  * 1 if they got merged.
1768  */
1769 static int ext4_ext_try_to_merge_right(struct inode *inode,
1770                                  struct ext4_ext_path *path,
1771                                  struct ext4_extent *ex)
1772 {
1773         struct ext4_extent_header *eh;
1774         unsigned int depth, len;
1775         int merge_done = 0, unwritten;
1776
1777         depth = ext_depth(inode);
1778         BUG_ON(path[depth].p_hdr == NULL);
1779         eh = path[depth].p_hdr;
1780
1781         while (ex < EXT_LAST_EXTENT(eh)) {
1782                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1783                         break;
1784                 /* merge with next extent! */
1785                 unwritten = ext4_ext_is_unwritten(ex);
1786                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1787                                 + ext4_ext_get_actual_len(ex + 1));
1788                 if (unwritten)
1789                         ext4_ext_mark_unwritten(ex);
1790
1791                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1792                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1793                                 * sizeof(struct ext4_extent);
1794                         memmove(ex + 1, ex + 2, len);
1795                 }
1796                 le16_add_cpu(&eh->eh_entries, -1);
1797                 merge_done = 1;
1798                 WARN_ON(eh->eh_entries == 0);
1799                 if (!eh->eh_entries)
1800                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1801         }
1802
1803         return merge_done;
1804 }
1805
1806 /*
1807  * This function does a very simple check to see if we can collapse
1808  * an extent tree with a single extent tree leaf block into the inode.
1809  */
1810 static void ext4_ext_try_to_merge_up(handle_t *handle,
1811                                      struct inode *inode,
1812                                      struct ext4_ext_path *path)
1813 {
1814         size_t s;
1815         unsigned max_root = ext4_ext_space_root(inode, 0);
1816         ext4_fsblk_t blk;
1817
1818         if ((path[0].p_depth != 1) ||
1819             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1820             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1821                 return;
1822
1823         /*
1824          * We need to modify the block allocation bitmap and the block
1825          * group descriptor to release the extent tree block.  If we
1826          * can't get the journal credits, give up.
1827          */
1828         if (ext4_journal_extend(handle, 2))
1829                 return;
1830
1831         /*
1832          * Copy the extent data up to the inode
1833          */
1834         blk = ext4_idx_pblock(path[0].p_idx);
1835         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1836                 sizeof(struct ext4_extent_idx);
1837         s += sizeof(struct ext4_extent_header);
1838
1839         path[1].p_maxdepth = path[0].p_maxdepth;
1840         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1841         path[0].p_depth = 0;
1842         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1843                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1844         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1845
1846         brelse(path[1].p_bh);
1847         ext4_free_blocks(handle, inode, NULL, blk, 1,
1848                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1849 }
1850
1851 /*
1852  * This function tries to merge the @ex extent to neighbours in the tree.
1853  * return 1 if merge left else 0.
1854  */
1855 static void ext4_ext_try_to_merge(handle_t *handle,
1856                                   struct inode *inode,
1857                                   struct ext4_ext_path *path,
1858                                   struct ext4_extent *ex) {
1859         struct ext4_extent_header *eh;
1860         unsigned int depth;
1861         int merge_done = 0;
1862
1863         depth = ext_depth(inode);
1864         BUG_ON(path[depth].p_hdr == NULL);
1865         eh = path[depth].p_hdr;
1866
1867         if (ex > EXT_FIRST_EXTENT(eh))
1868                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1869
1870         if (!merge_done)
1871                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1872
1873         ext4_ext_try_to_merge_up(handle, inode, path);
1874 }
1875
1876 /*
1877  * check if a portion of the "newext" extent overlaps with an
1878  * existing extent.
1879  *
1880  * If there is an overlap discovered, it updates the length of the newext
1881  * such that there will be no overlap, and then returns 1.
1882  * If there is no overlap found, it returns 0.
1883  */
1884 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1885                                            struct inode *inode,
1886                                            struct ext4_extent *newext,
1887                                            struct ext4_ext_path *path)
1888 {
1889         ext4_lblk_t b1, b2;
1890         unsigned int depth, len1;
1891         unsigned int ret = 0;
1892
1893         b1 = le32_to_cpu(newext->ee_block);
1894         len1 = ext4_ext_get_actual_len(newext);
1895         depth = ext_depth(inode);
1896         if (!path[depth].p_ext)
1897                 goto out;
1898         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1899
1900         /*
1901          * get the next allocated block if the extent in the path
1902          * is before the requested block(s)
1903          */
1904         if (b2 < b1) {
1905                 b2 = ext4_ext_next_allocated_block(path);
1906                 if (b2 == EXT_MAX_BLOCKS)
1907                         goto out;
1908                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1909         }
1910
1911         /* check for wrap through zero on extent logical start block*/
1912         if (b1 + len1 < b1) {
1913                 len1 = EXT_MAX_BLOCKS - b1;
1914                 newext->ee_len = cpu_to_le16(len1);
1915                 ret = 1;
1916         }
1917
1918         /* check for overlap */
1919         if (b1 + len1 > b2) {
1920                 newext->ee_len = cpu_to_le16(b2 - b1);
1921                 ret = 1;
1922         }
1923 out:
1924         return ret;
1925 }
1926
1927 /*
1928  * ext4_ext_insert_extent:
1929  * tries to merge requsted extent into the existing extent or
1930  * inserts requested extent as new one into the tree,
1931  * creating new leaf in the no-space case.
1932  */
1933 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1934                                 struct ext4_ext_path **ppath,
1935                                 struct ext4_extent *newext, int gb_flags)
1936 {
1937         struct ext4_ext_path *path = *ppath;
1938         struct ext4_extent_header *eh;
1939         struct ext4_extent *ex, *fex;
1940         struct ext4_extent *nearex; /* nearest extent */
1941         struct ext4_ext_path *npath = NULL;
1942         int depth, len, err;
1943         ext4_lblk_t next;
1944         int mb_flags = 0, unwritten;
1945
1946         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1947                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1948         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1949                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1950                 return -EFSCORRUPTED;
1951         }
1952         depth = ext_depth(inode);
1953         ex = path[depth].p_ext;
1954         eh = path[depth].p_hdr;
1955         if (unlikely(path[depth].p_hdr == NULL)) {
1956                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1957                 return -EFSCORRUPTED;
1958         }
1959
1960         /* try to insert block into found extent and return */
1961         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1962
1963                 /*
1964                  * Try to see whether we should rather test the extent on
1965                  * right from ex, or from the left of ex. This is because
1966                  * ext4_find_extent() can return either extent on the
1967                  * left, or on the right from the searched position. This
1968                  * will make merging more effective.
1969                  */
1970                 if (ex < EXT_LAST_EXTENT(eh) &&
1971                     (le32_to_cpu(ex->ee_block) +
1972                     ext4_ext_get_actual_len(ex) <
1973                     le32_to_cpu(newext->ee_block))) {
1974                         ex += 1;
1975                         goto prepend;
1976                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1977                            (le32_to_cpu(newext->ee_block) +
1978                            ext4_ext_get_actual_len(newext) <
1979                            le32_to_cpu(ex->ee_block)))
1980                         ex -= 1;
1981
1982                 /* Try to append newex to the ex */
1983                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1984                         ext_debug("append [%d]%d block to %u:[%d]%d"
1985                                   "(from %llu)\n",
1986                                   ext4_ext_is_unwritten(newext),
1987                                   ext4_ext_get_actual_len(newext),
1988                                   le32_to_cpu(ex->ee_block),
1989                                   ext4_ext_is_unwritten(ex),
1990                                   ext4_ext_get_actual_len(ex),
1991                                   ext4_ext_pblock(ex));
1992                         err = ext4_ext_get_access(handle, inode,
1993                                                   path + depth);
1994                         if (err)
1995                                 return err;
1996                         unwritten = ext4_ext_is_unwritten(ex);
1997                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1998                                         + ext4_ext_get_actual_len(newext));
1999                         if (unwritten)
2000                                 ext4_ext_mark_unwritten(ex);
2001                         eh = path[depth].p_hdr;
2002                         nearex = ex;
2003                         goto merge;
2004                 }
2005
2006 prepend:
2007                 /* Try to prepend newex to the ex */
2008                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2009                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2010                                   "(from %llu)\n",
2011                                   le32_to_cpu(newext->ee_block),
2012                                   ext4_ext_is_unwritten(newext),
2013                                   ext4_ext_get_actual_len(newext),
2014                                   le32_to_cpu(ex->ee_block),
2015                                   ext4_ext_is_unwritten(ex),
2016                                   ext4_ext_get_actual_len(ex),
2017                                   ext4_ext_pblock(ex));
2018                         err = ext4_ext_get_access(handle, inode,
2019                                                   path + depth);
2020                         if (err)
2021                                 return err;
2022
2023                         unwritten = ext4_ext_is_unwritten(ex);
2024                         ex->ee_block = newext->ee_block;
2025                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2026                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2027                                         + ext4_ext_get_actual_len(newext));
2028                         if (unwritten)
2029                                 ext4_ext_mark_unwritten(ex);
2030                         eh = path[depth].p_hdr;
2031                         nearex = ex;
2032                         goto merge;
2033                 }
2034         }
2035
2036         depth = ext_depth(inode);
2037         eh = path[depth].p_hdr;
2038         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2039                 goto has_space;
2040
2041         /* probably next leaf has space for us? */
2042         fex = EXT_LAST_EXTENT(eh);
2043         next = EXT_MAX_BLOCKS;
2044         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2045                 next = ext4_ext_next_leaf_block(path);
2046         if (next != EXT_MAX_BLOCKS) {
2047                 ext_debug("next leaf block - %u\n", next);
2048                 BUG_ON(npath != NULL);
2049                 npath = ext4_find_extent(inode, next, NULL, 0);
2050                 if (IS_ERR(npath))
2051                         return PTR_ERR(npath);
2052                 BUG_ON(npath->p_depth != path->p_depth);
2053                 eh = npath[depth].p_hdr;
2054                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2055                         ext_debug("next leaf isn't full(%d)\n",
2056                                   le16_to_cpu(eh->eh_entries));
2057                         path = npath;
2058                         goto has_space;
2059                 }
2060                 ext_debug("next leaf has no free space(%d,%d)\n",
2061                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2062         }
2063
2064         /*
2065          * There is no free space in the found leaf.
2066          * We're gonna add a new leaf in the tree.
2067          */
2068         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2069                 mb_flags |= EXT4_MB_USE_RESERVED;
2070         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2071                                        ppath, newext);
2072         if (err)
2073                 goto cleanup;
2074         depth = ext_depth(inode);
2075         eh = path[depth].p_hdr;
2076
2077 has_space:
2078         nearex = path[depth].p_ext;
2079
2080         err = ext4_ext_get_access(handle, inode, path + depth);
2081         if (err)
2082                 goto cleanup;
2083
2084         if (!nearex) {
2085                 /* there is no extent in this leaf, create first one */
2086                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2087                                 le32_to_cpu(newext->ee_block),
2088                                 ext4_ext_pblock(newext),
2089                                 ext4_ext_is_unwritten(newext),
2090                                 ext4_ext_get_actual_len(newext));
2091                 nearex = EXT_FIRST_EXTENT(eh);
2092         } else {
2093                 if (le32_to_cpu(newext->ee_block)
2094                            > le32_to_cpu(nearex->ee_block)) {
2095                         /* Insert after */
2096                         ext_debug("insert %u:%llu:[%d]%d before: "
2097                                         "nearest %p\n",
2098                                         le32_to_cpu(newext->ee_block),
2099                                         ext4_ext_pblock(newext),
2100                                         ext4_ext_is_unwritten(newext),
2101                                         ext4_ext_get_actual_len(newext),
2102                                         nearex);
2103                         nearex++;
2104                 } else {
2105                         /* Insert before */
2106                         BUG_ON(newext->ee_block == nearex->ee_block);
2107                         ext_debug("insert %u:%llu:[%d]%d after: "
2108                                         "nearest %p\n",
2109                                         le32_to_cpu(newext->ee_block),
2110                                         ext4_ext_pblock(newext),
2111                                         ext4_ext_is_unwritten(newext),
2112                                         ext4_ext_get_actual_len(newext),
2113                                         nearex);
2114                 }
2115                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2116                 if (len > 0) {
2117                         ext_debug("insert %u:%llu:[%d]%d: "
2118                                         "move %d extents from 0x%p to 0x%p\n",
2119                                         le32_to_cpu(newext->ee_block),
2120                                         ext4_ext_pblock(newext),
2121                                         ext4_ext_is_unwritten(newext),
2122                                         ext4_ext_get_actual_len(newext),
2123                                         len, nearex, nearex + 1);
2124                         memmove(nearex + 1, nearex,
2125                                 len * sizeof(struct ext4_extent));
2126                 }
2127         }
2128
2129         le16_add_cpu(&eh->eh_entries, 1);
2130         path[depth].p_ext = nearex;
2131         nearex->ee_block = newext->ee_block;
2132         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2133         nearex->ee_len = newext->ee_len;
2134
2135 merge:
2136         /* try to merge extents */
2137         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2138                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2139
2140
2141         /* time to correct all indexes above */
2142         err = ext4_ext_correct_indexes(handle, inode, path);
2143         if (err)
2144                 goto cleanup;
2145
2146         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2147
2148 cleanup:
2149         ext4_ext_drop_refs(npath);
2150         kfree(npath);
2151         return err;
2152 }
2153
2154 static int ext4_fill_fiemap_extents(struct inode *inode,
2155                                     ext4_lblk_t block, ext4_lblk_t num,
2156                                     struct fiemap_extent_info *fieinfo)
2157 {
2158         struct ext4_ext_path *path = NULL;
2159         struct ext4_extent *ex;
2160         struct extent_status es;
2161         ext4_lblk_t next, next_del, start = 0, end = 0;
2162         ext4_lblk_t last = block + num;
2163         int exists, depth = 0, err = 0;
2164         unsigned int flags = 0;
2165         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2166
2167         while (block < last && block != EXT_MAX_BLOCKS) {
2168                 num = last - block;
2169                 /* find extent for this block */
2170                 down_read(&EXT4_I(inode)->i_data_sem);
2171
2172                 path = ext4_find_extent(inode, block, &path, 0);
2173                 if (IS_ERR(path)) {
2174                         up_read(&EXT4_I(inode)->i_data_sem);
2175                         err = PTR_ERR(path);
2176                         path = NULL;
2177                         break;
2178                 }
2179
2180                 depth = ext_depth(inode);
2181                 if (unlikely(path[depth].p_hdr == NULL)) {
2182                         up_read(&EXT4_I(inode)->i_data_sem);
2183                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2184                         err = -EFSCORRUPTED;
2185                         break;
2186                 }
2187                 ex = path[depth].p_ext;
2188                 next = ext4_ext_next_allocated_block(path);
2189
2190                 flags = 0;
2191                 exists = 0;
2192                 if (!ex) {
2193                         /* there is no extent yet, so try to allocate
2194                          * all requested space */
2195                         start = block;
2196                         end = block + num;
2197                 } else if (le32_to_cpu(ex->ee_block) > block) {
2198                         /* need to allocate space before found extent */
2199                         start = block;
2200                         end = le32_to_cpu(ex->ee_block);
2201                         if (block + num < end)
2202                                 end = block + num;
2203                 } else if (block >= le32_to_cpu(ex->ee_block)
2204                                         + ext4_ext_get_actual_len(ex)) {
2205                         /* need to allocate space after found extent */
2206                         start = block;
2207                         end = block + num;
2208                         if (end >= next)
2209                                 end = next;
2210                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2211                         /*
2212                          * some part of requested space is covered
2213                          * by found extent
2214                          */
2215                         start = block;
2216                         end = le32_to_cpu(ex->ee_block)
2217                                 + ext4_ext_get_actual_len(ex);
2218                         if (block + num < end)
2219                                 end = block + num;
2220                         exists = 1;
2221                 } else {
2222                         BUG();
2223                 }
2224                 BUG_ON(end <= start);
2225
2226                 if (!exists) {
2227                         es.es_lblk = start;
2228                         es.es_len = end - start;
2229                         es.es_pblk = 0;
2230                 } else {
2231                         es.es_lblk = le32_to_cpu(ex->ee_block);
2232                         es.es_len = ext4_ext_get_actual_len(ex);
2233                         es.es_pblk = ext4_ext_pblock(ex);
2234                         if (ext4_ext_is_unwritten(ex))
2235                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2236                 }
2237
2238                 /*
2239                  * Find delayed extent and update es accordingly. We call
2240                  * it even in !exists case to find out whether es is the
2241                  * last existing extent or not.
2242                  */
2243                 next_del = ext4_find_delayed_extent(inode, &es);
2244                 if (!exists && next_del) {
2245                         exists = 1;
2246                         flags |= (FIEMAP_EXTENT_DELALLOC |
2247                                   FIEMAP_EXTENT_UNKNOWN);
2248                 }
2249                 up_read(&EXT4_I(inode)->i_data_sem);
2250
2251                 if (unlikely(es.es_len == 0)) {
2252                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2253                         err = -EFSCORRUPTED;
2254                         break;
2255                 }
2256
2257                 /*
2258                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2259                  * we need to check next == EXT_MAX_BLOCKS because it is
2260                  * possible that an extent is with unwritten and delayed
2261                  * status due to when an extent is delayed allocated and
2262                  * is allocated by fallocate status tree will track both of
2263                  * them in a extent.
2264                  *
2265                  * So we could return a unwritten and delayed extent, and
2266                  * its block is equal to 'next'.
2267                  */
2268                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2269                         flags |= FIEMAP_EXTENT_LAST;
2270                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2271                                      next != EXT_MAX_BLOCKS)) {
2272                                 EXT4_ERROR_INODE(inode,
2273                                                  "next extent == %u, next "
2274                                                  "delalloc extent = %u",
2275                                                  next, next_del);
2276                                 err = -EFSCORRUPTED;
2277                                 break;
2278                         }
2279                 }
2280
2281                 if (exists) {
2282                         err = fiemap_fill_next_extent(fieinfo,
2283                                 (__u64)es.es_lblk << blksize_bits,
2284                                 (__u64)es.es_pblk << blksize_bits,
2285                                 (__u64)es.es_len << blksize_bits,
2286                                 flags);
2287                         if (err < 0)
2288                                 break;
2289                         if (err == 1) {
2290                                 err = 0;
2291                                 break;
2292                         }
2293                 }
2294
2295                 block = es.es_lblk + es.es_len;
2296         }
2297
2298         ext4_ext_drop_refs(path);
2299         kfree(path);
2300         return err;
2301 }
2302
2303 /*
2304  * ext4_ext_determine_hole - determine hole around given block
2305  * @inode:      inode we lookup in
2306  * @path:       path in extent tree to @lblk
2307  * @lblk:       pointer to logical block around which we want to determine hole
2308  *
2309  * Determine hole length (and start if easily possible) around given logical
2310  * block. We don't try too hard to find the beginning of the hole but @path
2311  * actually points to extent before @lblk, we provide it.
2312  *
2313  * The function returns the length of a hole starting at @lblk. We update @lblk
2314  * to the beginning of the hole if we managed to find it.
2315  */
2316 static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2317                                            struct ext4_ext_path *path,
2318                                            ext4_lblk_t *lblk)
2319 {
2320         int depth = ext_depth(inode);
2321         struct ext4_extent *ex;
2322         ext4_lblk_t len;
2323
2324         ex = path[depth].p_ext;
2325         if (ex == NULL) {
2326                 /* there is no extent yet, so gap is [0;-] */
2327                 *lblk = 0;
2328                 len = EXT_MAX_BLOCKS;
2329         } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2330                 len = le32_to_cpu(ex->ee_block) - *lblk;
2331         } else if (*lblk >= le32_to_cpu(ex->ee_block)
2332                         + ext4_ext_get_actual_len(ex)) {
2333                 ext4_lblk_t next;
2334
2335                 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2336                 next = ext4_ext_next_allocated_block(path);
2337                 BUG_ON(next == *lblk);
2338                 len = next - *lblk;
2339         } else {
2340                 BUG();
2341         }
2342         return len;
2343 }
2344
2345 /*
2346  * ext4_ext_put_gap_in_cache:
2347  * calculate boundaries of the gap that the requested block fits into
2348  * and cache this gap
2349  */
2350 static void
2351 ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2352                           ext4_lblk_t hole_len)
2353 {
2354         struct extent_status es;
2355
2356         ext4_es_find_delayed_extent_range(inode, hole_start,
2357                                           hole_start + hole_len - 1, &es);
2358         if (es.es_len) {
2359                 /* There's delayed extent containing lblock? */
2360                 if (es.es_lblk <= hole_start)
2361                         return;
2362                 hole_len = min(es.es_lblk - hole_start, hole_len);
2363         }
2364         ext_debug(" -> %u:%u\n", hole_start, hole_len);
2365         ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2366                               EXTENT_STATUS_HOLE);
2367 }
2368
2369 /*
2370  * ext4_ext_rm_idx:
2371  * removes index from the index block.
2372  */
2373 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2374                         struct ext4_ext_path *path, int depth)
2375 {
2376         int err;
2377         ext4_fsblk_t leaf;
2378
2379         /* free index block */
2380         depth--;
2381         path = path + depth;
2382         leaf = ext4_idx_pblock(path->p_idx);
2383         if (unlikely(path->p_hdr->eh_entries == 0)) {
2384                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2385                 return -EFSCORRUPTED;
2386         }
2387         err = ext4_ext_get_access(handle, inode, path);
2388         if (err)
2389                 return err;
2390
2391         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2392                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2393                 len *= sizeof(struct ext4_extent_idx);
2394                 memmove(path->p_idx, path->p_idx + 1, len);
2395         }
2396
2397         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2398         err = ext4_ext_dirty(handle, inode, path);
2399         if (err)
2400                 return err;
2401         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2402         trace_ext4_ext_rm_idx(inode, leaf);
2403
2404         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2405                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2406
2407         while (--depth >= 0) {
2408                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2409                         break;
2410                 path--;
2411                 err = ext4_ext_get_access(handle, inode, path);
2412                 if (err)
2413                         break;
2414                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2415                 err = ext4_ext_dirty(handle, inode, path);
2416                 if (err)
2417                         break;
2418         }
2419         return err;
2420 }
2421
2422 /*
2423  * ext4_ext_calc_credits_for_single_extent:
2424  * This routine returns max. credits that needed to insert an extent
2425  * to the extent tree.
2426  * When pass the actual path, the caller should calculate credits
2427  * under i_data_sem.
2428  */
2429 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2430                                                 struct ext4_ext_path *path)
2431 {
2432         if (path) {
2433                 int depth = ext_depth(inode);
2434                 int ret = 0;
2435
2436                 /* probably there is space in leaf? */
2437                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2438                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2439
2440                         /*
2441                          *  There are some space in the leaf tree, no
2442                          *  need to account for leaf block credit
2443                          *
2444                          *  bitmaps and block group descriptor blocks
2445                          *  and other metadata blocks still need to be
2446                          *  accounted.
2447                          */
2448                         /* 1 bitmap, 1 block group descriptor */
2449                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2450                         return ret;
2451                 }
2452         }
2453
2454         return ext4_chunk_trans_blocks(inode, nrblocks);
2455 }
2456
2457 /*
2458  * How many index/leaf blocks need to change/allocate to add @extents extents?
2459  *
2460  * If we add a single extent, then in the worse case, each tree level
2461  * index/leaf need to be changed in case of the tree split.
2462  *
2463  * If more extents are inserted, they could cause the whole tree split more
2464  * than once, but this is really rare.
2465  */
2466 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2467 {
2468         int index;
2469         int depth;
2470
2471         /* If we are converting the inline data, only one is needed here. */
2472         if (ext4_has_inline_data(inode))
2473                 return 1;
2474
2475         depth = ext_depth(inode);
2476
2477         if (extents <= 1)
2478                 index = depth * 2;
2479         else
2480                 index = depth * 3;
2481
2482         return index;
2483 }
2484
2485 static inline int get_default_free_blocks_flags(struct inode *inode)
2486 {
2487         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2488                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2489         else if (ext4_should_journal_data(inode))
2490                 return EXT4_FREE_BLOCKS_FORGET;
2491         return 0;
2492 }
2493
2494 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2495                               struct ext4_extent *ex,
2496                               long long *partial_cluster,
2497                               ext4_lblk_t from, ext4_lblk_t to)
2498 {
2499         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2500         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2501         ext4_fsblk_t pblk;
2502         int flags = get_default_free_blocks_flags(inode);
2503
2504         /*
2505          * For bigalloc file systems, we never free a partial cluster
2506          * at the beginning of the extent.  Instead, we make a note
2507          * that we tried freeing the cluster, and check to see if we
2508          * need to free it on a subsequent call to ext4_remove_blocks,
2509          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2510          */
2511         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2512
2513         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2514         /*
2515          * If we have a partial cluster, and it's different from the
2516          * cluster of the last block, we need to explicitly free the
2517          * partial cluster here.
2518          */
2519         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2520         if (*partial_cluster > 0 &&
2521             *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2522                 ext4_free_blocks(handle, inode, NULL,
2523                                  EXT4_C2B(sbi, *partial_cluster),
2524                                  sbi->s_cluster_ratio, flags);
2525                 *partial_cluster = 0;
2526         }
2527
2528 #ifdef EXTENTS_STATS
2529         {
2530                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2531                 spin_lock(&sbi->s_ext_stats_lock);
2532                 sbi->s_ext_blocks += ee_len;
2533                 sbi->s_ext_extents++;
2534                 if (ee_len < sbi->s_ext_min)
2535                         sbi->s_ext_min = ee_len;
2536                 if (ee_len > sbi->s_ext_max)
2537                         sbi->s_ext_max = ee_len;
2538                 if (ext_depth(inode) > sbi->s_depth_max)
2539                         sbi->s_depth_max = ext_depth(inode);
2540                 spin_unlock(&sbi->s_ext_stats_lock);
2541         }
2542 #endif
2543         if (from >= le32_to_cpu(ex->ee_block)
2544             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2545                 /* tail removal */
2546                 ext4_lblk_t num;
2547                 long long first_cluster;
2548
2549                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2550                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2551                 /*
2552                  * Usually we want to free partial cluster at the end of the
2553                  * extent, except for the situation when the cluster is still
2554                  * used by any other extent (partial_cluster is negative).
2555                  */
2556                 if (*partial_cluster < 0 &&
2557                     *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))
2558                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2559
2560                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2561                           num, pblk, *partial_cluster);
2562                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2563                 /*
2564                  * If the block range to be freed didn't start at the
2565                  * beginning of a cluster, and we removed the entire
2566                  * extent and the cluster is not used by any other extent,
2567                  * save the partial cluster here, since we might need to
2568                  * delete if we determine that the truncate or punch hole
2569                  * operation has removed all of the blocks in the cluster.
2570                  * If that cluster is used by another extent, preserve its
2571                  * negative value so it isn't freed later on.
2572                  *
2573                  * If the whole extent wasn't freed, we've reached the
2574                  * start of the truncated/punched region and have finished
2575                  * removing blocks.  If there's a partial cluster here it's
2576                  * shared with the remainder of the extent and is no longer
2577                  * a candidate for removal.
2578                  */
2579                 if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {
2580                         first_cluster = (long long) EXT4_B2C(sbi, pblk);
2581                         if (first_cluster != -*partial_cluster)
2582                                 *partial_cluster = first_cluster;
2583                 } else {
2584                         *partial_cluster = 0;
2585                 }
2586         } else
2587                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2588                            "%u-%u from %u:%u",
2589                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2590         return 0;
2591 }
2592
2593
2594 /*
2595  * ext4_ext_rm_leaf() Removes the extents associated with the
2596  * blocks appearing between "start" and "end".  Both "start"
2597  * and "end" must appear in the same extent or EIO is returned.
2598  *
2599  * @handle: The journal handle
2600  * @inode:  The files inode
2601  * @path:   The path to the leaf
2602  * @partial_cluster: The cluster which we'll have to free if all extents
2603  *                   has been released from it.  However, if this value is
2604  *                   negative, it's a cluster just to the right of the
2605  *                   punched region and it must not be freed.
2606  * @start:  The first block to remove
2607  * @end:   The last block to remove
2608  */
2609 static int
2610 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2611                  struct ext4_ext_path *path,
2612                  long long *partial_cluster,
2613                  ext4_lblk_t start, ext4_lblk_t end)
2614 {
2615         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2616         int err = 0, correct_index = 0;
2617         int depth = ext_depth(inode), credits;
2618         struct ext4_extent_header *eh;
2619         ext4_lblk_t a, b;
2620         unsigned num;
2621         ext4_lblk_t ex_ee_block;
2622         unsigned short ex_ee_len;
2623         unsigned unwritten = 0;
2624         struct ext4_extent *ex;
2625         ext4_fsblk_t pblk;
2626
2627         /* the header must be checked already in ext4_ext_remove_space() */
2628         ext_debug("truncate since %u in leaf to %u\n", start, end);
2629         if (!path[depth].p_hdr)
2630                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2631         eh = path[depth].p_hdr;
2632         if (unlikely(path[depth].p_hdr == NULL)) {
2633                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2634                 return -EFSCORRUPTED;
2635         }
2636         /* find where to start removing */
2637         ex = path[depth].p_ext;
2638         if (!ex)
2639                 ex = EXT_LAST_EXTENT(eh);
2640
2641         ex_ee_block = le32_to_cpu(ex->ee_block);
2642         ex_ee_len = ext4_ext_get_actual_len(ex);
2643
2644         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2645
2646         while (ex >= EXT_FIRST_EXTENT(eh) &&
2647                         ex_ee_block + ex_ee_len > start) {
2648
2649                 if (ext4_ext_is_unwritten(ex))
2650                         unwritten = 1;
2651                 else
2652                         unwritten = 0;
2653
2654                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2655                           unwritten, ex_ee_len);
2656                 path[depth].p_ext = ex;
2657
2658                 a = ex_ee_block > start ? ex_ee_block : start;
2659                 b = ex_ee_block+ex_ee_len - 1 < end ?
2660                         ex_ee_block+ex_ee_len - 1 : end;
2661
2662                 ext_debug("  border %u:%u\n", a, b);
2663
2664                 /* If this extent is beyond the end of the hole, skip it */
2665                 if (end < ex_ee_block) {
2666                         /*
2667                          * We're going to skip this extent and move to another,
2668                          * so note that its first cluster is in use to avoid
2669                          * freeing it when removing blocks.  Eventually, the
2670                          * right edge of the truncated/punched region will
2671                          * be just to the left.
2672                          */
2673                         if (sbi->s_cluster_ratio > 1) {
2674                                 pblk = ext4_ext_pblock(ex);
2675                                 *partial_cluster =
2676                                         -(long long) EXT4_B2C(sbi, pblk);
2677                         }
2678                         ex--;
2679                         ex_ee_block = le32_to_cpu(ex->ee_block);
2680                         ex_ee_len = ext4_ext_get_actual_len(ex);
2681                         continue;
2682                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2683                         EXT4_ERROR_INODE(inode,
2684                                          "can not handle truncate %u:%u "
2685                                          "on extent %u:%u",
2686                                          start, end, ex_ee_block,
2687                                          ex_ee_block + ex_ee_len - 1);
2688                         err = -EFSCORRUPTED;
2689                         goto out;
2690                 } else if (a != ex_ee_block) {
2691                         /* remove tail of the extent */
2692                         num = a - ex_ee_block;
2693                 } else {
2694                         /* remove whole extent: excellent! */
2695                         num = 0;
2696                 }
2697                 /*
2698                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2699                  * descriptor) for each block group; assume two block
2700                  * groups plus ex_ee_len/blocks_per_block_group for
2701                  * the worst case
2702                  */
2703                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2704                 if (ex == EXT_FIRST_EXTENT(eh)) {
2705                         correct_index = 1;
2706                         credits += (ext_depth(inode)) + 1;
2707                 }
2708                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2709
2710                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2711                 if (err)
2712                         goto out;
2713
2714                 err = ext4_ext_get_access(handle, inode, path + depth);
2715                 if (err)
2716                         goto out;
2717
2718                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2719                                          a, b);
2720                 if (err)
2721                         goto out;
2722
2723                 if (num == 0)
2724                         /* this extent is removed; mark slot entirely unused */
2725                         ext4_ext_store_pblock(ex, 0);
2726
2727                 ex->ee_len = cpu_to_le16(num);
2728                 /*
2729                  * Do not mark unwritten if all the blocks in the
2730                  * extent have been removed.
2731                  */
2732                 if (unwritten && num)
2733                         ext4_ext_mark_unwritten(ex);
2734                 /*
2735                  * If the extent was completely released,
2736                  * we need to remove it from the leaf
2737                  */
2738                 if (num == 0) {
2739                         if (end != EXT_MAX_BLOCKS - 1) {
2740                                 /*
2741                                  * For hole punching, we need to scoot all the
2742                                  * extents up when an extent is removed so that
2743                                  * we dont have blank extents in the middle
2744                                  */
2745                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2746                                         sizeof(struct ext4_extent));
2747
2748                                 /* Now get rid of the one at the end */
2749                                 memset(EXT_LAST_EXTENT(eh), 0,
2750                                         sizeof(struct ext4_extent));
2751                         }
2752                         le16_add_cpu(&eh->eh_entries, -1);
2753                 }
2754
2755                 err = ext4_ext_dirty(handle, inode, path + depth);
2756                 if (err)
2757                         goto out;
2758
2759                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2760                                 ext4_ext_pblock(ex));
2761                 ex--;
2762                 ex_ee_block = le32_to_cpu(ex->ee_block);
2763                 ex_ee_len = ext4_ext_get_actual_len(ex);
2764         }
2765
2766         if (correct_index && eh->eh_entries)
2767                 err = ext4_ext_correct_indexes(handle, inode, path);
2768
2769         /*
2770          * If there's a partial cluster and at least one extent remains in
2771          * the leaf, free the partial cluster if it isn't shared with the
2772          * current extent.  If it is shared with the current extent
2773          * we zero partial_cluster because we've reached the start of the
2774          * truncated/punched region and we're done removing blocks.
2775          */
2776         if (*partial_cluster > 0 && ex >= EXT_FIRST_EXTENT(eh)) {
2777                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2778                 if (*partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2779                         ext4_free_blocks(handle, inode, NULL,
2780                                          EXT4_C2B(sbi, *partial_cluster),
2781                                          sbi->s_cluster_ratio,
2782                                          get_default_free_blocks_flags(inode));
2783                 }
2784                 *partial_cluster = 0;
2785         }
2786
2787         /* if this leaf is free, then we should
2788          * remove it from index block above */
2789         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2790                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2791
2792 out:
2793         return err;
2794 }
2795
2796 /*
2797  * ext4_ext_more_to_rm:
2798  * returns 1 if current index has to be freed (even partial)
2799  */
2800 static int
2801 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2802 {
2803         BUG_ON(path->p_idx == NULL);
2804
2805         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2806                 return 0;
2807
2808         /*
2809          * if truncate on deeper level happened, it wasn't partial,
2810          * so we have to consider current index for truncation
2811          */
2812         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2813                 return 0;
2814         return 1;
2815 }
2816
2817 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2818                           ext4_lblk_t end)
2819 {
2820         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2821         int depth = ext_depth(inode);
2822         struct ext4_ext_path *path = NULL;
2823         long long partial_cluster = 0;
2824         handle_t *handle;
2825         int i = 0, err = 0;
2826
2827         ext_debug("truncate since %u to %u\n", start, end);
2828
2829         /* probably first extent we're gonna free will be last in block */
2830         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2831         if (IS_ERR(handle))
2832                 return PTR_ERR(handle);
2833
2834 again:
2835         trace_ext4_ext_remove_space(inode, start, end, depth);
2836
2837         /*
2838          * Check if we are removing extents inside the extent tree. If that
2839          * is the case, we are going to punch a hole inside the extent tree
2840          * so we have to check whether we need to split the extent covering
2841          * the last block to remove so we can easily remove the part of it
2842          * in ext4_ext_rm_leaf().
2843          */
2844         if (end < EXT_MAX_BLOCKS - 1) {
2845                 struct ext4_extent *ex;
2846                 ext4_lblk_t ee_block, ex_end, lblk;
2847                 ext4_fsblk_t pblk;
2848
2849                 /* find extent for or closest extent to this block */
2850                 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2851                 if (IS_ERR(path)) {
2852                         ext4_journal_stop(handle);
2853                         return PTR_ERR(path);
2854                 }
2855                 depth = ext_depth(inode);
2856                 /* Leaf not may not exist only if inode has no blocks at all */
2857                 ex = path[depth].p_ext;
2858                 if (!ex) {
2859                         if (depth) {
2860                                 EXT4_ERROR_INODE(inode,
2861                                                  "path[%d].p_hdr == NULL",
2862                                                  depth);
2863                                 err = -EFSCORRUPTED;
2864                         }
2865                         goto out;
2866                 }
2867
2868                 ee_block = le32_to_cpu(ex->ee_block);
2869                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2870
2871                 /*
2872                  * See if the last block is inside the extent, if so split
2873                  * the extent at 'end' block so we can easily remove the
2874                  * tail of the first part of the split extent in
2875                  * ext4_ext_rm_leaf().
2876                  */
2877                 if (end >= ee_block && end < ex_end) {
2878
2879                         /*
2880                          * If we're going to split the extent, note that
2881                          * the cluster containing the block after 'end' is
2882                          * in use to avoid freeing it when removing blocks.
2883                          */
2884                         if (sbi->s_cluster_ratio > 1) {
2885                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2886                                 partial_cluster =
2887                                         -(long long) EXT4_B2C(sbi, pblk);
2888                         }
2889
2890                         /*
2891                          * Split the extent in two so that 'end' is the last
2892                          * block in the first new extent. Also we should not
2893                          * fail removing space due to ENOSPC so try to use
2894                          * reserved block if that happens.
2895                          */
2896                         err = ext4_force_split_extent_at(handle, inode, &path,
2897                                                          end + 1, 1);
2898                         if (err < 0)
2899                                 goto out;
2900
2901                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end) {
2902                         /*
2903                          * If there's an extent to the right its first cluster
2904                          * contains the immediate right boundary of the
2905                          * truncated/punched region.  Set partial_cluster to
2906                          * its negative value so it won't be freed if shared
2907                          * with the current extent.  The end < ee_block case
2908                          * is handled in ext4_ext_rm_leaf().
2909                          */
2910                         lblk = ex_end + 1;
2911                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2912                                                     &ex);
2913                         if (err)
2914                                 goto out;
2915                         if (pblk)
2916                                 partial_cluster =
2917                                         -(long long) EXT4_B2C(sbi, pblk);
2918                 }
2919         }
2920         /*
2921          * We start scanning from right side, freeing all the blocks
2922          * after i_size and walking into the tree depth-wise.
2923          */
2924         depth = ext_depth(inode);
2925         if (path) {
2926                 int k = i = depth;
2927                 while (--k > 0)
2928                         path[k].p_block =
2929                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2930         } else {
2931                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2932                                GFP_NOFS);
2933                 if (path == NULL) {
2934                         ext4_journal_stop(handle);
2935                         return -ENOMEM;
2936                 }
2937                 path[0].p_maxdepth = path[0].p_depth = depth;
2938                 path[0].p_hdr = ext_inode_hdr(inode);
2939                 i = 0;
2940
2941                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2942                         err = -EFSCORRUPTED;
2943                         goto out;
2944                 }
2945         }
2946         err = 0;
2947
2948         while (i >= 0 && err == 0) {
2949                 if (i == depth) {
2950                         /* this is leaf block */
2951                         err = ext4_ext_rm_leaf(handle, inode, path,
2952                                                &partial_cluster, start,
2953                                                end);
2954                         /* root level has p_bh == NULL, brelse() eats this */
2955                         brelse(path[i].p_bh);
2956                         path[i].p_bh = NULL;
2957                         i--;
2958                         continue;
2959                 }
2960
2961                 /* this is index block */
2962                 if (!path[i].p_hdr) {
2963                         ext_debug("initialize header\n");
2964                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2965                 }
2966
2967                 if (!path[i].p_idx) {
2968                         /* this level hasn't been touched yet */
2969                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2970                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2971                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2972                                   path[i].p_hdr,
2973                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2974                 } else {
2975                         /* we were already here, see at next index */
2976                         path[i].p_idx--;
2977                 }
2978
2979                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2980                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2981                                 path[i].p_idx);
2982                 if (ext4_ext_more_to_rm(path + i)) {
2983                         struct buffer_head *bh;
2984                         /* go to the next level */
2985                         ext_debug("move to level %d (block %llu)\n",
2986                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2987                         memset(path + i + 1, 0, sizeof(*path));
2988                         bh = read_extent_tree_block(inode,
2989                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2990                                 EXT4_EX_NOCACHE);
2991                         if (IS_ERR(bh)) {
2992                                 /* should we reset i_size? */
2993                                 err = PTR_ERR(bh);
2994                                 break;
2995                         }
2996                         /* Yield here to deal with large extent trees.
2997                          * Should be a no-op if we did IO above. */
2998                         cond_resched();
2999                         if (WARN_ON(i + 1 > depth)) {
3000                                 err = -EFSCORRUPTED;
3001                                 break;
3002                         }
3003                         path[i + 1].p_bh = bh;
3004
3005                         /* save actual number of indexes since this
3006                          * number is changed at the next iteration */
3007                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3008                         i++;
3009                 } else {
3010                         /* we finished processing this index, go up */
3011                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3012                                 /* index is empty, remove it;
3013                                  * handle must be already prepared by the
3014                                  * truncatei_leaf() */
3015                                 err = ext4_ext_rm_idx(handle, inode, path, i);
3016                         }
3017                         /* root level has p_bh == NULL, brelse() eats this */
3018                         brelse(path[i].p_bh);
3019                         path[i].p_bh = NULL;
3020                         i--;
3021                         ext_debug("return to level %d\n", i);
3022                 }
3023         }
3024
3025         trace_ext4_ext_remove_space_done(inode, start, end, depth,
3026                         partial_cluster, path->p_hdr->eh_entries);
3027
3028         /*
3029          * If we still have something in the partial cluster and we have removed
3030          * even the first extent, then we should free the blocks in the partial
3031          * cluster as well.  (This code will only run when there are no leaves
3032          * to the immediate left of the truncated/punched region.)
3033          */
3034         if (partial_cluster > 0 && err == 0) {
3035                 /* don't zero partial_cluster since it's not used afterwards */
3036                 ext4_free_blocks(handle, inode, NULL,
3037                                  EXT4_C2B(sbi, partial_cluster),
3038                                  sbi->s_cluster_ratio,
3039                                  get_default_free_blocks_flags(inode));
3040         }
3041
3042         /* TODO: flexible tree reduction should be here */
3043         if (path->p_hdr->eh_entries == 0) {
3044                 /*
3045                  * truncate to zero freed all the tree,
3046                  * so we need to correct eh_depth
3047                  */
3048                 err = ext4_ext_get_access(handle, inode, path);
3049                 if (err == 0) {
3050                         ext_inode_hdr(inode)->eh_depth = 0;
3051                         ext_inode_hdr(inode)->eh_max =
3052                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3053                         err = ext4_ext_dirty(handle, inode, path);
3054                 }
3055         }
3056 out:
3057         ext4_ext_drop_refs(path);
3058         kfree(path);
3059         path = NULL;
3060         if (err == -EAGAIN)
3061                 goto again;
3062         ext4_journal_stop(handle);
3063
3064         return err;
3065 }
3066
3067 /*
3068  * called at mount time
3069  */
3070 void ext4_ext_init(struct super_block *sb)
3071 {
3072         /*
3073          * possible initialization would be here
3074          */
3075
3076         if (ext4_has_feature_extents(sb)) {
3077 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3078                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3079 #ifdef AGGRESSIVE_TEST
3080                        ", aggressive tests"
3081 #endif
3082 #ifdef CHECK_BINSEARCH
3083                        ", check binsearch"
3084 #endif
3085 #ifdef EXTENTS_STATS
3086                        ", stats"
3087 #endif
3088                        "\n");
3089 #endif
3090 #ifdef EXTENTS_STATS
3091                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3092                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3093                 EXT4_SB(sb)->s_ext_max = 0;
3094 #endif
3095         }
3096 }
3097
3098 /*
3099  * called at umount time
3100  */
3101 void ext4_ext_release(struct super_block *sb)
3102 {
3103         if (!ext4_has_feature_extents(sb))
3104                 return;
3105
3106 #ifdef EXTENTS_STATS
3107         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3108                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3109                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3110                         sbi->s_ext_blocks, sbi->s_ext_extents,
3111                         sbi->s_ext_blocks / sbi->s_ext_extents);
3112                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3113                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3114         }
3115 #endif
3116 }
3117
3118 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3119 {
3120         ext4_lblk_t  ee_block;
3121         ext4_fsblk_t ee_pblock;
3122         unsigned int ee_len;
3123
3124         ee_block  = le32_to_cpu(ex->ee_block);
3125         ee_len    = ext4_ext_get_actual_len(ex);
3126         ee_pblock = ext4_ext_pblock(ex);
3127
3128         if (ee_len == 0)
3129                 return 0;
3130
3131         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3132                                      EXTENT_STATUS_WRITTEN);
3133 }
3134
3135 /* FIXME!! we need to try to merge to left or right after zero-out  */
3136 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3137 {
3138         ext4_fsblk_t ee_pblock;
3139         unsigned int ee_len;
3140
3141         ee_len    = ext4_ext_get_actual_len(ex);
3142         ee_pblock = ext4_ext_pblock(ex);
3143         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3144                                   ee_len);
3145 }
3146
3147 /*
3148  * ext4_split_extent_at() splits an extent at given block.
3149  *
3150  * @handle: the journal handle
3151  * @inode: the file inode
3152  * @path: the path to the extent
3153  * @split: the logical block where the extent is splitted.
3154  * @split_flags: indicates if the extent could be zeroout if split fails, and
3155  *               the states(init or unwritten) of new extents.
3156  * @flags: flags used to insert new extent to extent tree.
3157  *
3158  *
3159  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3160  * of which are deterimined by split_flag.
3161  *
3162  * There are two cases:
3163  *  a> the extent are splitted into two extent.
3164  *  b> split is not needed, and just mark the extent.
3165  *
3166  * return 0 on success.
3167  */
3168 static int ext4_split_extent_at(handle_t *handle,
3169                              struct inode *inode,
3170                              struct ext4_ext_path **ppath,
3171                              ext4_lblk_t split,
3172                              int split_flag,
3173                              int flags)
3174 {
3175         struct ext4_ext_path *path = *ppath;
3176         ext4_fsblk_t newblock;
3177         ext4_lblk_t ee_block;
3178         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3179         struct ext4_extent *ex2 = NULL;
3180         unsigned int ee_len, depth;
3181         int err = 0;
3182
3183         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3184                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3185
3186         ext_debug("ext4_split_extents_at: inode %lu, logical"
3187                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3188
3189         ext4_ext_show_leaf(inode, path);
3190
3191         depth = ext_depth(inode);
3192         ex = path[depth].p_ext;
3193         ee_block = le32_to_cpu(ex->ee_block);
3194         ee_len = ext4_ext_get_actual_len(ex);
3195         newblock = split - ee_block + ext4_ext_pblock(ex);
3196
3197         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3198         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3199                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3200                              EXT4_EXT_MARK_UNWRIT1 |
3201                              EXT4_EXT_MARK_UNWRIT2));
3202
3203         err = ext4_ext_get_access(handle, inode, path + depth);
3204         if (err)
3205                 goto out;
3206
3207         if (split == ee_block) {
3208                 /*
3209                  * case b: block @split is the block that the extent begins with
3210                  * then we just change the state of the extent, and splitting
3211                  * is not needed.
3212                  */
3213                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3214                         ext4_ext_mark_unwritten(ex);
3215                 else
3216                         ext4_ext_mark_initialized(ex);
3217
3218                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3219                         ext4_ext_try_to_merge(handle, inode, path, ex);
3220
3221                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3222                 goto out;
3223         }
3224
3225         /* case a */
3226         memcpy(&orig_ex, ex, sizeof(orig_ex));
3227         ex->ee_len = cpu_to_le16(split - ee_block);
3228         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3229                 ext4_ext_mark_unwritten(ex);
3230
3231         /*
3232          * path may lead to new leaf, not to original leaf any more
3233          * after ext4_ext_insert_extent() returns,
3234          */
3235         err = ext4_ext_dirty(handle, inode, path + depth);
3236         if (err)
3237                 goto fix_extent_len;
3238
3239         ex2 = &newex;
3240         ex2->ee_block = cpu_to_le32(split);
3241         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3242         ext4_ext_store_pblock(ex2, newblock);
3243         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3244                 ext4_ext_mark_unwritten(ex2);
3245
3246         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3247         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3248                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3249                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3250                                 err = ext4_ext_zeroout(inode, ex2);
3251                                 zero_ex.ee_block = ex2->ee_block;
3252                                 zero_ex.ee_len = cpu_to_le16(
3253                                                 ext4_ext_get_actual_len(ex2));
3254                                 ext4_ext_store_pblock(&zero_ex,
3255                                                       ext4_ext_pblock(ex2));
3256                         } else {
3257                                 err = ext4_ext_zeroout(inode, ex);
3258                                 zero_ex.ee_block = ex->ee_block;
3259                                 zero_ex.ee_len = cpu_to_le16(
3260                                                 ext4_ext_get_actual_len(ex));
3261                                 ext4_ext_store_pblock(&zero_ex,
3262                                                       ext4_ext_pblock(ex));
3263                         }
3264                 } else {
3265                         err = ext4_ext_zeroout(inode, &orig_ex);
3266                         zero_ex.ee_block = orig_ex.ee_block;
3267                         zero_ex.ee_len = cpu_to_le16(
3268                                                 ext4_ext_get_actual_len(&orig_ex));
3269                         ext4_ext_store_pblock(&zero_ex,
3270                                               ext4_ext_pblock(&orig_ex));
3271                 }
3272
3273                 if (err)
3274                         goto fix_extent_len;
3275                 /* update the extent length and mark as initialized */
3276                 ex->ee_len = cpu_to_le16(ee_len);
3277                 ext4_ext_try_to_merge(handle, inode, path, ex);
3278                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3279                 if (err)
3280                         goto fix_extent_len;
3281
3282                 /* update extent status tree */
3283                 err = ext4_zeroout_es(inode, &zero_ex);
3284
3285                 goto out;
3286         } else if (err)
3287                 goto fix_extent_len;
3288
3289 out:
3290         ext4_ext_show_leaf(inode, path);
3291         return err;
3292
3293 fix_extent_len:
3294         ex->ee_len = orig_ex.ee_len;
3295         ext4_ext_dirty(handle, inode, path + path->p_depth);
3296         return err;
3297 }
3298
3299 /*
3300  * ext4_split_extents() splits an extent and mark extent which is covered
3301  * by @map as split_flags indicates
3302  *
3303  * It may result in splitting the extent into multiple extents (up to three)
3304  * There are three possibilities:
3305  *   a> There is no split required
3306  *   b> Splits in two extents: Split is happening at either end of the extent
3307  *   c> Splits in three extents: Somone is splitting in middle of the extent
3308  *
3309  */
3310 static int ext4_split_extent(handle_t *handle,
3311                               struct inode *inode,
3312                               struct ext4_ext_path **ppath,
3313                               struct ext4_map_blocks *map,
3314                               int split_flag,
3315                               int flags)
3316 {
3317         struct ext4_ext_path *path = *ppath;
3318         ext4_lblk_t ee_block;
3319         struct ext4_extent *ex;
3320         unsigned int ee_len, depth;
3321         int err = 0;
3322         int unwritten;
3323         int split_flag1, flags1;
3324         int allocated = map->m_len;
3325
3326         depth = ext_depth(inode);
3327         ex = path[depth].p_ext;
3328         ee_block = le32_to_cpu(ex->ee_block);
3329         ee_len = ext4_ext_get_actual_len(ex);
3330         unwritten = ext4_ext_is_unwritten(ex);
3331
3332         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3333                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3334                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3335                 if (unwritten)
3336                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3337                                        EXT4_EXT_MARK_UNWRIT2;
3338                 if (split_flag & EXT4_EXT_DATA_VALID2)
3339                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3340                 err = ext4_split_extent_at(handle, inode, ppath,
3341                                 map->m_lblk + map->m_len, split_flag1, flags1);
3342                 if (err)
3343                         goto out;
3344         } else {
3345                 allocated = ee_len - (map->m_lblk - ee_block);
3346         }
3347         /*
3348          * Update path is required because previous ext4_split_extent_at() may
3349          * result in split of original leaf or extent zeroout.
3350          */
3351         path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3352         if (IS_ERR(path))
3353                 return PTR_ERR(path);
3354         depth = ext_depth(inode);
3355         ex = path[depth].p_ext;
3356         if (!ex) {
3357                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3358                                  (unsigned long) map->m_lblk);
3359                 return -EFSCORRUPTED;
3360         }
3361         unwritten = ext4_ext_is_unwritten(ex);
3362         split_flag1 = 0;
3363
3364         if (map->m_lblk >= ee_block) {
3365                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3366                 if (unwritten) {
3367                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3368                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3369                                                      EXT4_EXT_MARK_UNWRIT2);
3370                 }
3371                 err = ext4_split_extent_at(handle, inode, ppath,
3372                                 map->m_lblk, split_flag1, flags);
3373                 if (err)
3374                         goto out;
3375         }
3376
3377         ext4_ext_show_leaf(inode, path);
3378 out:
3379         return err ? err : allocated;
3380 }
3381
3382 /*
3383  * This function is called by ext4_ext_map_blocks() if someone tries to write
3384  * to an unwritten extent. It may result in splitting the unwritten
3385  * extent into multiple extents (up to three - one initialized and two
3386  * unwritten).
3387  * There are three possibilities:
3388  *   a> There is no split required: Entire extent should be initialized
3389  *   b> Splits in two extents: Write is happening at either end of the extent
3390  *   c> Splits in three extents: Somone is writing in middle of the extent
3391  *
3392  * Pre-conditions:
3393  *  - The extent pointed to by 'path' is unwritten.
3394  *  - The extent pointed to by 'path' contains a superset
3395  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3396  *
3397  * Post-conditions on success:
3398  *  - the returned value is the number of blocks beyond map->l_lblk
3399  *    that are allocated and initialized.
3400  *    It is guaranteed to be >= map->m_len.
3401  */
3402 static int ext4_ext_convert_to_initialized(handle_t *handle,
3403                                            struct inode *inode,
3404                                            struct ext4_map_blocks *map,
3405                                            struct ext4_ext_path **ppath,
3406                                            int flags)
3407 {
3408         struct ext4_ext_path *path = *ppath;
3409         struct ext4_sb_info *sbi;
3410         struct ext4_extent_header *eh;
3411         struct ext4_map_blocks split_map;
3412         struct ext4_extent zero_ex;
3413         struct ext4_extent *ex, *abut_ex;
3414         ext4_lblk_t ee_block, eof_block;
3415         unsigned int ee_len, depth, map_len = map->m_len;
3416         int allocated = 0, max_zeroout = 0;
3417         int err = 0;
3418         int split_flag = 0;
3419
3420         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3421                 "block %llu, max_blocks %u\n", inode->i_ino,
3422                 (unsigned long long)map->m_lblk, map_len);
3423
3424         sbi = EXT4_SB(inode->i_sb);
3425         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3426                 inode->i_sb->s_blocksize_bits;
3427         if (eof_block < map->m_lblk + map_len)
3428                 eof_block = map->m_lblk + map_len;
3429
3430         depth = ext_depth(inode);
3431         eh = path[depth].p_hdr;
3432         ex = path[depth].p_ext;
3433         ee_block = le32_to_cpu(ex->ee_block);
3434         ee_len = ext4_ext_get_actual_len(ex);
3435         zero_ex.ee_len = 0;
3436
3437         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3438
3439         /* Pre-conditions */
3440         BUG_ON(!ext4_ext_is_unwritten(ex));
3441         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3442
3443         /*
3444          * Attempt to transfer newly initialized blocks from the currently
3445          * unwritten extent to its neighbor. This is much cheaper
3446          * than an insertion followed by a merge as those involve costly
3447          * memmove() calls. Transferring to the left is the common case in
3448          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3449          * followed by append writes.
3450          *
3451          * Limitations of the current logic:
3452          *  - L1: we do not deal with writes covering the whole extent.
3453          *    This would require removing the extent if the transfer
3454          *    is possible.
3455          *  - L2: we only attempt to merge with an extent stored in the
3456          *    same extent tree node.
3457          */
3458         if ((map->m_lblk == ee_block) &&
3459                 /* See if we can merge left */
3460                 (map_len < ee_len) &&           /*L1*/
3461                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3462                 ext4_lblk_t prev_lblk;
3463                 ext4_fsblk_t prev_pblk, ee_pblk;
3464                 unsigned int prev_len;
3465
3466                 abut_ex = ex - 1;
3467                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3468                 prev_len = ext4_ext_get_actual_len(abut_ex);
3469                 prev_pblk = ext4_ext_pblock(abut_ex);
3470                 ee_pblk = ext4_ext_pblock(ex);
3471
3472                 /*
3473                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3474                  * upon those conditions:
3475                  * - C1: abut_ex is initialized,
3476                  * - C2: abut_ex is logically abutting ex,
3477                  * - C3: abut_ex is physically abutting ex,
3478                  * - C4: abut_ex can receive the additional blocks without
3479                  *   overflowing the (initialized) length limit.
3480                  */
3481                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3482                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3483                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3484                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3485                         err = ext4_ext_get_access(handle, inode, path + depth);
3486                         if (err)
3487                                 goto out;
3488
3489                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3490                                 map, ex, abut_ex);
3491
3492                         /* Shift the start of ex by 'map_len' blocks */
3493                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3494                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3495                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3496                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3497
3498                         /* Extend abut_ex by 'map_len' blocks */
3499                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3500
3501                         /* Result: number of initialized blocks past m_lblk */
3502                         allocated = map_len;
3503                 }
3504         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3505                    (map_len < ee_len) &&        /*L1*/
3506                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3507                 /* See if we can merge right */
3508                 ext4_lblk_t next_lblk;
3509                 ext4_fsblk_t next_pblk, ee_pblk;
3510                 unsigned int next_len;
3511
3512                 abut_ex = ex + 1;
3513                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3514                 next_len = ext4_ext_get_actual_len(abut_ex);
3515                 next_pblk = ext4_ext_pblock(abut_ex);
3516                 ee_pblk = ext4_ext_pblock(ex);
3517
3518                 /*
3519                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3520                  * upon those conditions:
3521                  * - C1: abut_ex is initialized,
3522                  * - C2: abut_ex is logically abutting ex,
3523                  * - C3: abut_ex is physically abutting ex,
3524                  * - C4: abut_ex can receive the additional blocks without
3525                  *   overflowing the (initialized) length limit.
3526                  */
3527                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3528                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3529                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3530                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3531                         err = ext4_ext_get_access(handle, inode, path + depth);
3532                         if (err)
3533                                 goto out;
3534
3535                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3536                                 map, ex, abut_ex);
3537
3538                         /* Shift the start of abut_ex by 'map_len' blocks */
3539                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3540                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3541                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3542                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3543
3544                         /* Extend abut_ex by 'map_len' blocks */
3545                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3546
3547                         /* Result: number of initialized blocks past m_lblk */
3548                         allocated = map_len;
3549                 }
3550         }
3551         if (allocated) {
3552                 /* Mark the block containing both extents as dirty */
3553                 ext4_ext_dirty(handle, inode, path + depth);
3554
3555                 /* Update path to point to the right extent */
3556                 path[depth].p_ext = abut_ex;
3557                 goto out;
3558         } else
3559                 allocated = ee_len - (map->m_lblk - ee_block);
3560
3561         WARN_ON(map->m_lblk < ee_block);
3562         /*
3563          * It is safe to convert extent to initialized via explicit
3564          * zeroout only if extent is fully inside i_size or new_size.
3565          */
3566         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3567
3568         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3569                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3570                         (inode->i_sb->s_blocksize_bits - 10);
3571
3572         if (ext4_encrypted_inode(inode))
3573                 max_zeroout = 0;
3574
3575         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3576         if (max_zeroout && (ee_len <= max_zeroout)) {
3577                 err = ext4_ext_zeroout(inode, ex);
3578                 if (err)
3579                         goto out;
3580                 zero_ex.ee_block = ex->ee_block;
3581                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3582                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3583
3584                 err = ext4_ext_get_access(handle, inode, path + depth);
3585                 if (err)
3586                         goto out;
3587                 ext4_ext_mark_initialized(ex);
3588                 ext4_ext_try_to_merge(handle, inode, path, ex);
3589                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3590                 goto out;
3591         }
3592
3593         /*
3594          * four cases:
3595          * 1. split the extent into three extents.
3596          * 2. split the extent into two extents, zeroout the first half.
3597          * 3. split the extent into two extents, zeroout the second half.
3598          * 4. split the extent into two extents with out zeroout.
3599          */
3600         split_map.m_lblk = map->m_lblk;
3601         split_map.m_len = map->m_len;
3602
3603         if (max_zeroout && (allocated > map->m_len)) {
3604                 if (allocated <= max_zeroout) {
3605                         /* case 3 */
3606                         zero_ex.ee_block =
3607                                          cpu_to_le32(map->m_lblk);
3608                         zero_ex.ee_len = cpu_to_le16(allocated);
3609                         ext4_ext_store_pblock(&zero_ex,
3610                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3611                         err = ext4_ext_zeroout(inode, &zero_ex);
3612                         if (err)
3613                                 goto out;
3614                         split_map.m_lblk = map->m_lblk;
3615                         split_map.m_len = allocated;
3616                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3617                         /* case 2 */
3618                         if (map->m_lblk != ee_block) {
3619                                 zero_ex.ee_block = ex->ee_block;
3620                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3621                                                         ee_block);
3622                                 ext4_ext_store_pblock(&zero_ex,
3623                                                       ext4_ext_pblock(ex));
3624                                 err = ext4_ext_zeroout(inode, &zero_ex);
3625                                 if (err)
3626                                         goto out;
3627                         }
3628
3629                         split_map.m_lblk = ee_block;
3630                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3631                         allocated = map->m_len;
3632                 }
3633         }
3634
3635         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3636                                 flags);
3637         if (err > 0)
3638                 err = 0;
3639 out:
3640         /* If we have gotten a failure, don't zero out status tree */
3641         if (!err)
3642                 err = ext4_zeroout_es(inode, &zero_ex);
3643         return err ? err : allocated;
3644 }
3645
3646 /*
3647  * This function is called by ext4_ext_map_blocks() from
3648  * ext4_get_blocks_dio_write() when DIO to write
3649  * to an unwritten extent.
3650  *
3651  * Writing to an unwritten extent may result in splitting the unwritten
3652  * extent into multiple initialized/unwritten extents (up to three)
3653  * There are three possibilities:
3654  *   a> There is no split required: Entire extent should be unwritten
3655  *   b> Splits in two extents: Write is happening at either end of the extent
3656  *   c> Splits in three extents: Somone is writing in middle of the extent
3657  *
3658  * This works the same way in the case of initialized -> unwritten conversion.
3659  *
3660  * One of more index blocks maybe needed if the extent tree grow after
3661  * the unwritten extent split. To prevent ENOSPC occur at the IO
3662  * complete, we need to split the unwritten extent before DIO submit
3663  * the IO. The unwritten extent called at this time will be split
3664  * into three unwritten extent(at most). After IO complete, the part
3665  * being filled will be convert to initialized by the end_io callback function
3666  * via ext4_convert_unwritten_extents().
3667  *
3668  * Returns the size of unwritten extent to be written on success.
3669  */
3670 static int ext4_split_convert_extents(handle_t *handle,
3671                                         struct inode *inode,
3672                                         struct ext4_map_blocks *map,
3673                                         struct ext4_ext_path **ppath,
3674                                         int flags)
3675 {
3676         struct ext4_ext_path *path = *ppath;
3677         ext4_lblk_t eof_block;
3678         ext4_lblk_t ee_block;
3679         struct ext4_extent *ex;
3680         unsigned int ee_len;
3681         int split_flag = 0, depth;
3682
3683         ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3684                   __func__, inode->i_ino,
3685                   (unsigned long long)map->m_lblk, map->m_len);
3686
3687         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3688                 inode->i_sb->s_blocksize_bits;
3689         if (eof_block < map->m_lblk + map->m_len)
3690                 eof_block = map->m_lblk + map->m_len;
3691         /*
3692          * It is safe to convert extent to initialized via explicit
3693          * zeroout only if extent is fully insde i_size or new_size.
3694          */
3695         depth = ext_depth(inode);
3696         ex = path[depth].p_ext;
3697         ee_block = le32_to_cpu(ex->ee_block);
3698         ee_len = ext4_ext_get_actual_len(ex);
3699
3700         /* Convert to unwritten */
3701         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3702                 split_flag |= EXT4_EXT_DATA_VALID1;
3703         /* Convert to initialized */
3704         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3705                 split_flag |= ee_block + ee_len <= eof_block ?
3706                               EXT4_EXT_MAY_ZEROOUT : 0;
3707                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3708         }
3709         flags |= EXT4_GET_BLOCKS_PRE_IO;
3710         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3711 }
3712
3713 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3714                                                 struct inode *inode,
3715                                                 struct ext4_map_blocks *map,
3716                                                 struct ext4_ext_path **ppath)
3717 {
3718         struct ext4_ext_path *path = *ppath;
3719         struct ext4_extent *ex;
3720         ext4_lblk_t ee_block;
3721         unsigned int ee_len;
3722         int depth;
3723         int err = 0;
3724
3725         depth = ext_depth(inode);
3726         ex = path[depth].p_ext;
3727         ee_block = le32_to_cpu(ex->ee_block);
3728         ee_len = ext4_ext_get_actual_len(ex);
3729
3730         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3731                 "block %llu, max_blocks %u\n", inode->i_ino,
3732                   (unsigned long long)ee_block, ee_len);
3733
3734         /* If extent is larger than requested it is a clear sign that we still
3735          * have some extent state machine issues left. So extent_split is still
3736          * required.
3737          * TODO: Once all related issues will be fixed this situation should be
3738          * illegal.
3739          */
3740         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3741 #ifdef EXT4_DEBUG
3742                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3743                              " len %u; IO logical block %llu, len %u",
3744                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3745                              (unsigned long long)map->m_lblk, map->m_len);
3746 #endif
3747                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3748                                                  EXT4_GET_BLOCKS_CONVERT);
3749                 if (err < 0)
3750                         return err;
3751                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3752                 if (IS_ERR(path))
3753                         return PTR_ERR(path);
3754                 depth = ext_depth(inode);
3755                 ex = path[depth].p_ext;
3756         }
3757
3758         err = ext4_ext_get_access(handle, inode, path + depth);
3759         if (err)
3760                 goto out;
3761         /* first mark the extent as initialized */
3762         ext4_ext_mark_initialized(ex);
3763
3764         /* note: ext4_ext_correct_indexes() isn't needed here because
3765          * borders are not changed
3766          */
3767         ext4_ext_try_to_merge(handle, inode, path, ex);
3768
3769         /* Mark modified extent as dirty */
3770         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3771 out:
3772         ext4_ext_show_leaf(inode, path);
3773         return err;
3774 }
3775
3776 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3777                         sector_t block, int count)
3778 {
3779         int i;
3780         for (i = 0; i < count; i++)
3781                 unmap_underlying_metadata(bdev, block + i);
3782 }
3783
3784 /*
3785  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3786  */
3787 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3788                               ext4_lblk_t lblk,
3789                               struct ext4_ext_path *path,
3790                               unsigned int len)
3791 {
3792         int i, depth;
3793         struct ext4_extent_header *eh;
3794         struct ext4_extent *last_ex;
3795
3796         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3797                 return 0;
3798
3799         depth = ext_depth(inode);
3800         eh = path[depth].p_hdr;
3801
3802         /*
3803          * We're going to remove EOFBLOCKS_FL entirely in future so we
3804          * do not care for this case anymore. Simply remove the flag
3805          * if there are no extents.
3806          */
3807         if (unlikely(!eh->eh_entries))
3808                 goto out;
3809         last_ex = EXT_LAST_EXTENT(eh);
3810         /*
3811          * We should clear the EOFBLOCKS_FL flag if we are writing the
3812          * last block in the last extent in the file.  We test this by
3813          * first checking to see if the caller to
3814          * ext4_ext_get_blocks() was interested in the last block (or
3815          * a block beyond the last block) in the current extent.  If
3816          * this turns out to be false, we can bail out from this
3817          * function immediately.
3818          */
3819         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3820             ext4_ext_get_actual_len(last_ex))
3821                 return 0;
3822         /*
3823          * If the caller does appear to be planning to write at or
3824          * beyond the end of the current extent, we then test to see
3825          * if the current extent is the last extent in the file, by
3826          * checking to make sure it was reached via the rightmost node
3827          * at each level of the tree.
3828          */
3829         for (i = depth-1; i >= 0; i--)
3830                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3831                         return 0;
3832 out:
3833         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3834         return ext4_mark_inode_dirty(handle, inode);
3835 }
3836
3837 /**
3838  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3839  *
3840  * Return 1 if there is a delalloc block in the range, otherwise 0.
3841  */
3842 int ext4_find_delalloc_range(struct inode *inode,
3843                              ext4_lblk_t lblk_start,
3844                              ext4_lblk_t lblk_end)
3845 {
3846         struct extent_status es;
3847
3848         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3849         if (es.es_len == 0)
3850                 return 0; /* there is no delay extent in this tree */
3851         else if (es.es_lblk <= lblk_start &&
3852                  lblk_start < es.es_lblk + es.es_len)
3853                 return 1;
3854         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3855                 return 1;
3856         else
3857                 return 0;
3858 }
3859
3860 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3861 {
3862         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3863         ext4_lblk_t lblk_start, lblk_end;
3864         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3865         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3866
3867         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3868 }
3869
3870 /**
3871  * Determines how many complete clusters (out of those specified by the 'map')
3872  * are under delalloc and were reserved quota for.
3873  * This function is called when we are writing out the blocks that were
3874  * originally written with their allocation delayed, but then the space was
3875  * allocated using fallocate() before the delayed allocation could be resolved.
3876  * The cases to look for are:
3877  * ('=' indicated delayed allocated blocks
3878  *  '-' indicates non-delayed allocated blocks)
3879  * (a) partial clusters towards beginning and/or end outside of allocated range
3880  *     are not delalloc'ed.
3881  *      Ex:
3882  *      |----c---=|====c====|====c====|===-c----|
3883  *               |++++++ allocated ++++++|
3884  *      ==> 4 complete clusters in above example
3885  *
3886  * (b) partial cluster (outside of allocated range) towards either end is
3887  *     marked for delayed allocation. In this case, we will exclude that
3888  *     cluster.
3889  *      Ex:
3890  *      |----====c========|========c========|
3891  *           |++++++ allocated ++++++|
3892  *      ==> 1 complete clusters in above example
3893  *
3894  *      Ex:
3895  *      |================c================|
3896  *            |++++++ allocated ++++++|
3897  *      ==> 0 complete clusters in above example
3898  *
3899  * The ext4_da_update_reserve_space will be called only if we
3900  * determine here that there were some "entire" clusters that span
3901  * this 'allocated' range.
3902  * In the non-bigalloc case, this function will just end up returning num_blks
3903  * without ever calling ext4_find_delalloc_range.
3904  */
3905 static unsigned int
3906 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3907                            unsigned int num_blks)
3908 {
3909         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3910         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3911         ext4_lblk_t lblk_from, lblk_to, c_offset;
3912         unsigned int allocated_clusters = 0;
3913
3914         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3915         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3916
3917         /* max possible clusters for this allocation */
3918         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3919
3920         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3921
3922         /* Check towards left side */
3923         c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3924         if (c_offset) {
3925                 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3926                 lblk_to = lblk_from + c_offset - 1;
3927
3928                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3929                         allocated_clusters--;
3930         }
3931
3932         /* Now check towards right. */
3933         c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3934         if (allocated_clusters && c_offset) {
3935                 lblk_from = lblk_start + num_blks;
3936                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3937
3938                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3939                         allocated_clusters--;
3940         }
3941
3942         return allocated_clusters;
3943 }
3944
3945 static int
3946 convert_initialized_extent(handle_t *handle, struct inode *inode,
3947                            struct ext4_map_blocks *map,
3948                            struct ext4_ext_path **ppath,
3949                            unsigned int allocated)
3950 {
3951         struct ext4_ext_path *path = *ppath;
3952         struct ext4_extent *ex;
3953         ext4_lblk_t ee_block;
3954         unsigned int ee_len;
3955         int depth;
3956         int err = 0;
3957
3958         /*
3959          * Make sure that the extent is no bigger than we support with
3960          * unwritten extent
3961          */
3962         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3963                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3964
3965         depth = ext_depth(inode);
3966         ex = path[depth].p_ext;
3967         ee_block = le32_to_cpu(ex->ee_block);
3968         ee_len = ext4_ext_get_actual_len(ex);
3969
3970         ext_debug("%s: inode %lu, logical"
3971                 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3972                   (unsigned long long)ee_block, ee_len);
3973
3974         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3975                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3976                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3977                 if (err < 0)
3978                         return err;
3979                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3980                 if (IS_ERR(path))
3981                         return PTR_ERR(path);
3982                 depth = ext_depth(inode);
3983                 ex = path[depth].p_ext;
3984                 if (!ex) {
3985                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3986                                          (unsigned long) map->m_lblk);
3987                         return -EFSCORRUPTED;
3988                 }
3989         }
3990
3991         err = ext4_ext_get_access(handle, inode, path + depth);
3992         if (err)
3993                 return err;
3994         /* first mark the extent as unwritten */
3995         ext4_ext_mark_unwritten(ex);
3996
3997         /* note: ext4_ext_correct_indexes() isn't needed here because
3998          * borders are not changed
3999          */
4000         ext4_ext_try_to_merge(handle, inode, path, ex);
4001
4002         /* Mark modified extent as dirty */
4003         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
4004         if (err)
4005                 return err;
4006         ext4_ext_show_leaf(inode, path);
4007
4008         ext4_update_inode_fsync_trans(handle, inode, 1);
4009         err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
4010         if (err)
4011                 return err;
4012         map->m_flags |= EXT4_MAP_UNWRITTEN;
4013         if (allocated > map->m_len)
4014                 allocated = map->m_len;
4015         map->m_len = allocated;
4016         return allocated;
4017 }
4018
4019 static int
4020 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4021                         struct ext4_map_blocks *map,
4022                         struct ext4_ext_path **ppath, int flags,
4023                         unsigned int allocated, ext4_fsblk_t newblock)
4024 {
4025         struct ext4_ext_path *path = *ppath;
4026         int ret = 0;
4027         int err = 0;
4028
4029         ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4030                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
4031                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4032                   flags, allocated);
4033         ext4_ext_show_leaf(inode, path);
4034
4035         /*
4036          * When writing into unwritten space, we should not fail to
4037          * allocate metadata blocks for the new extent block if needed.
4038          */
4039         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4040
4041         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4042                                                     allocated, newblock);
4043
4044         /* get_block() before submit the IO, split the extent */
4045         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4046                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4047                                          flags | EXT4_GET_BLOCKS_CONVERT);
4048                 if (ret <= 0)
4049                         goto out;
4050                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4051                 goto out;
4052         }
4053         /* IO end_io complete, convert the filled extent to written */
4054         if (flags & EXT4_GET_BLOCKS_CONVERT) {
4055                 if (flags & EXT4_GET_BLOCKS_ZERO) {
4056                         if (allocated > map->m_len)
4057                                 allocated = map->m_len;
4058                         err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4059                                                  allocated);
4060                         if (err < 0)
4061                                 goto out2;
4062                 }
4063                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4064                                                            ppath);
4065                 if (ret >= 0) {
4066                         ext4_update_inode_fsync_trans(handle, inode, 1);
4067                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
4068                                                  path, map->m_len);
4069                 } else
4070                         err = ret;
4071                 map->m_flags |= EXT4_MAP_MAPPED;
4072                 map->m_pblk = newblock;
4073                 if (allocated > map->m_len)
4074                         allocated = map->m_len;
4075                 map->m_len = allocated;
4076                 goto out2;
4077         }
4078         /* buffered IO case */
4079         /*
4080          * repeat fallocate creation request
4081          * we already have an unwritten extent
4082          */
4083         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4084                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4085                 goto map_out;
4086         }
4087
4088         /* buffered READ or buffered write_begin() lookup */
4089         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4090                 /*
4091                  * We have blocks reserved already.  We
4092                  * return allocated blocks so that delalloc
4093                  * won't do block reservation for us.  But
4094                  * the buffer head will be unmapped so that
4095                  * a read from the block returns 0s.
4096                  */
4097                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4098                 goto out1;
4099         }
4100
4101         /* buffered write, writepage time, convert*/
4102         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4103         if (ret >= 0)
4104                 ext4_update_inode_fsync_trans(handle, inode, 1);
4105 out:
4106         if (ret <= 0) {
4107                 err = ret;
4108                 goto out2;
4109         } else
4110                 allocated = ret;
4111         map->m_flags |= EXT4_MAP_NEW;
4112         /*
4113          * if we allocated more blocks than requested
4114          * we need to make sure we unmap the extra block
4115          * allocated. The actual needed block will get
4116          * unmapped later when we find the buffer_head marked
4117          * new.
4118          */
4119         if (allocated > map->m_len) {
4120                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4121                                         newblock + map->m_len,
4122                                         allocated - map->m_len);
4123                 allocated = map->m_len;
4124         }
4125         map->m_len = allocated;
4126
4127         /*
4128          * If we have done fallocate with the offset that is already
4129          * delayed allocated, we would have block reservation
4130          * and quota reservation done in the delayed write path.
4131          * But fallocate would have already updated quota and block
4132          * count for this offset. So cancel these reservation
4133          */
4134         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4135                 unsigned int reserved_clusters;
4136                 reserved_clusters = get_reserved_cluster_alloc(inode,
4137                                 map->m_lblk, map->m_len);
4138                 if (reserved_clusters)
4139                         ext4_da_update_reserve_space(inode,
4140                                                      reserved_clusters,
4141                                                      0);
4142         }
4143
4144 map_out:
4145         map->m_flags |= EXT4_MAP_MAPPED;
4146         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4147                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4148                                          map->m_len);
4149                 if (err < 0)
4150                         goto out2;
4151         }
4152 out1:
4153         if (allocated > map->m_len)
4154                 allocated = map->m_len;
4155         ext4_ext_show_leaf(inode, path);
4156         map->m_pblk = newblock;
4157         map->m_len = allocated;
4158 out2:
4159         return err ? err : allocated;
4160 }
4161
4162 /*
4163  * get_implied_cluster_alloc - check to see if the requested
4164  * allocation (in the map structure) overlaps with a cluster already
4165  * allocated in an extent.
4166  *      @sb     The filesystem superblock structure
4167  *      @map    The requested lblk->pblk mapping
4168  *      @ex     The extent structure which might contain an implied
4169  *                      cluster allocation
4170  *
4171  * This function is called by ext4_ext_map_blocks() after we failed to
4172  * find blocks that were already in the inode's extent tree.  Hence,
4173  * we know that the beginning of the requested region cannot overlap
4174  * the extent from the inode's extent tree.  There are three cases we
4175  * want to catch.  The first is this case:
4176  *
4177  *               |--- cluster # N--|
4178  *    |--- extent ---|  |---- requested region ---|
4179  *                      |==========|
4180  *
4181  * The second case that we need to test for is this one:
4182  *
4183  *   |--------- cluster # N ----------------|
4184  *         |--- requested region --|   |------- extent ----|
4185  *         |=======================|
4186  *
4187  * The third case is when the requested region lies between two extents
4188  * within the same cluster:
4189  *          |------------- cluster # N-------------|
4190  * |----- ex -----|                  |---- ex_right ----|
4191  *                  |------ requested region ------|
4192  *                  |================|
4193  *
4194  * In each of the above cases, we need to set the map->m_pblk and
4195  * map->m_len so it corresponds to the return the extent labelled as
4196  * "|====|" from cluster #N, since it is already in use for data in
4197  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4198  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4199  * as a new "allocated" block region.  Otherwise, we will return 0 and
4200  * ext4_ext_map_blocks() will then allocate one or more new clusters
4201  * by calling ext4_mb_new_blocks().
4202  */
4203 static int get_implied_cluster_alloc(struct super_block *sb,
4204                                      struct ext4_map_blocks *map,
4205                                      struct ext4_extent *ex,
4206                                      struct ext4_ext_path *path)
4207 {
4208         struct ext4_sb_info *sbi = EXT4_SB(sb);
4209         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4210         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4211         ext4_lblk_t rr_cluster_start;
4212         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4213         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4214         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4215
4216         /* The extent passed in that we are trying to match */
4217         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4218         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4219
4220         /* The requested region passed into ext4_map_blocks() */
4221         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4222
4223         if ((rr_cluster_start == ex_cluster_end) ||
4224             (rr_cluster_start == ex_cluster_start)) {
4225                 if (rr_cluster_start == ex_cluster_end)
4226                         ee_start += ee_len - 1;
4227                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4228                 map->m_len = min(map->m_len,
4229                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4230                 /*
4231                  * Check for and handle this case:
4232                  *
4233                  *   |--------- cluster # N-------------|
4234                  *                     |------- extent ----|
4235                  *         |--- requested region ---|
4236                  *         |===========|
4237                  */
4238
4239                 if (map->m_lblk < ee_block)
4240                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4241
4242                 /*
4243                  * Check for the case where there is already another allocated
4244                  * block to the right of 'ex' but before the end of the cluster.
4245                  *
4246                  *          |------------- cluster # N-------------|
4247                  * |----- ex -----|                  |---- ex_right ----|
4248                  *                  |------ requested region ------|
4249                  *                  |================|
4250                  */
4251                 if (map->m_lblk > ee_block) {
4252                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4253                         map->m_len = min(map->m_len, next - map->m_lblk);
4254                 }
4255
4256                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4257                 return 1;
4258         }
4259
4260         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4261         return 0;
4262 }
4263
4264
4265 /*
4266  * Block allocation/map/preallocation routine for extents based files
4267  *
4268  *
4269  * Need to be called with
4270  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4271  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4272  *
4273  * return > 0, number of of blocks already mapped/allocated
4274  *          if create == 0 and these are pre-allocated blocks
4275  *              buffer head is unmapped
4276  *          otherwise blocks are mapped
4277  *
4278  * return = 0, if plain look up failed (blocks have not been allocated)
4279  *          buffer head is unmapped
4280  *
4281  * return < 0, error case.
4282  */
4283 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4284                         struct ext4_map_blocks *map, int flags)
4285 {
4286         struct ext4_ext_path *path = NULL;
4287         struct ext4_extent newex, *ex, *ex2;
4288         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4289         ext4_fsblk_t newblock = 0;
4290         int free_on_err = 0, err = 0, depth, ret;
4291         unsigned int allocated = 0, offset = 0;
4292         unsigned int allocated_clusters = 0;
4293         struct ext4_allocation_request ar;
4294         ext4_lblk_t cluster_offset;
4295         bool map_from_cluster = false;
4296
4297         ext_debug("blocks %u/%u requested for inode %lu\n",
4298                   map->m_lblk, map->m_len, inode->i_ino);
4299         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4300
4301         /* find extent for this block */
4302         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4303         if (IS_ERR(path)) {
4304                 err = PTR_ERR(path);
4305                 path = NULL;
4306                 goto out2;
4307         }
4308
4309         depth = ext_depth(inode);
4310
4311         /*
4312          * consistent leaf must not be empty;
4313          * this situation is possible, though, _during_ tree modification;
4314          * this is why assert can't be put in ext4_find_extent()
4315          */
4316         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4317                 EXT4_ERROR_INODE(inode, "bad extent address "
4318                                  "lblock: %lu, depth: %d pblock %lld",
4319                                  (unsigned long) map->m_lblk, depth,
4320                                  path[depth].p_block);
4321                 err = -EFSCORRUPTED;
4322                 goto out2;
4323         }
4324
4325         ex = path[depth].p_ext;
4326         if (ex) {
4327                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4328                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4329                 unsigned short ee_len;
4330
4331
4332                 /*
4333                  * unwritten extents are treated as holes, except that
4334                  * we split out initialized portions during a write.
4335                  */
4336                 ee_len = ext4_ext_get_actual_len(ex);
4337
4338                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4339
4340                 /* if found extent covers block, simply return it */
4341                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4342                         newblock = map->m_lblk - ee_block + ee_start;
4343                         /* number of remaining blocks in the extent */
4344                         allocated = ee_len - (map->m_lblk - ee_block);
4345                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4346                                   ee_block, ee_len, newblock);
4347
4348                         /*
4349                          * If the extent is initialized check whether the
4350                          * caller wants to convert it to unwritten.
4351                          */
4352                         if ((!ext4_ext_is_unwritten(ex)) &&
4353                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4354                                 allocated = convert_initialized_extent(
4355                                                 handle, inode, map, &path,
4356                                                 allocated);
4357                                 goto out2;
4358                         } else if (!ext4_ext_is_unwritten(ex))
4359                                 goto out;
4360
4361                         ret = ext4_ext_handle_unwritten_extents(
4362                                 handle, inode, map, &path, flags,
4363                                 allocated, newblock);
4364                         if (ret < 0)
4365                                 err = ret;
4366                         else
4367                                 allocated = ret;
4368                         goto out2;
4369                 }
4370         }
4371
4372         /*
4373          * requested block isn't allocated yet;
4374          * we couldn't try to create block if create flag is zero
4375          */
4376         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4377                 ext4_lblk_t hole_start, hole_len;
4378
4379                 hole_start = map->m_lblk;
4380                 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4381                 /*
4382                  * put just found gap into cache to speed up
4383                  * subsequent requests
4384                  */
4385                 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4386
4387                 /* Update hole_len to reflect hole size after map->m_lblk */
4388                 if (hole_start != map->m_lblk)
4389                         hole_len -= map->m_lblk - hole_start;
4390                 map->m_pblk = 0;
4391                 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4392
4393                 goto out2;
4394         }
4395
4396         /*
4397          * Okay, we need to do block allocation.
4398          */
4399         newex.ee_block = cpu_to_le32(map->m_lblk);
4400         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4401
4402         /*
4403          * If we are doing bigalloc, check to see if the extent returned
4404          * by ext4_find_extent() implies a cluster we can use.
4405          */
4406         if (cluster_offset && ex &&
4407             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4408                 ar.len = allocated = map->m_len;
4409                 newblock = map->m_pblk;
4410                 map_from_cluster = true;
4411                 goto got_allocated_blocks;
4412         }
4413
4414         /* find neighbour allocated blocks */
4415         ar.lleft = map->m_lblk;
4416         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4417         if (err)
4418                 goto out2;
4419         ar.lright = map->m_lblk;
4420         ex2 = NULL;
4421         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4422         if (err)
4423                 goto out2;
4424
4425         /* Check if the extent after searching to the right implies a
4426          * cluster we can use. */
4427         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4428             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4429                 ar.len = allocated = map->m_len;
4430                 newblock = map->m_pblk;
4431                 map_from_cluster = true;
4432                 goto got_allocated_blocks;
4433         }
4434
4435         /*
4436          * See if request is beyond maximum number of blocks we can have in
4437          * a single extent. For an initialized extent this limit is
4438          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4439          * EXT_UNWRITTEN_MAX_LEN.
4440          */
4441         if (map->m_len > EXT_INIT_MAX_LEN &&
4442             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4443                 map->m_len = EXT_INIT_MAX_LEN;
4444         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4445                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4446                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4447
4448         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4449         newex.ee_len = cpu_to_le16(map->m_len);
4450         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4451         if (err)
4452                 allocated = ext4_ext_get_actual_len(&newex);
4453         else
4454                 allocated = map->m_len;
4455
4456         /* allocate new block */
4457         ar.inode = inode;
4458         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4459         ar.logical = map->m_lblk;
4460         /*
4461          * We calculate the offset from the beginning of the cluster
4462          * for the logical block number, since when we allocate a
4463          * physical cluster, the physical block should start at the
4464          * same offset from the beginning of the cluster.  This is
4465          * needed so that future calls to get_implied_cluster_alloc()
4466          * work correctly.
4467          */
4468         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4469         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4470         ar.goal -= offset;
4471         ar.logical -= offset;
4472         if (S_ISREG(inode->i_mode))
4473                 ar.flags = EXT4_MB_HINT_DATA;
4474         else
4475                 /* disable in-core preallocation for non-regular files */
4476                 ar.flags = 0;
4477         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4478                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4479         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4480                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4481         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4482                 ar.flags |= EXT4_MB_USE_RESERVED;
4483         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4484         if (!newblock)
4485                 goto out2;
4486         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4487                   ar.goal, newblock, allocated);
4488         free_on_err = 1;
4489         allocated_clusters = ar.len;
4490         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4491         if (ar.len > allocated)
4492                 ar.len = allocated;
4493
4494 got_allocated_blocks:
4495         /* try to insert new extent into found leaf and return */
4496         ext4_ext_store_pblock(&newex, newblock + offset);
4497         newex.ee_len = cpu_to_le16(ar.len);
4498         /* Mark unwritten */
4499         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4500                 ext4_ext_mark_unwritten(&newex);
4501                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4502         }
4503
4504         err = 0;
4505         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4506                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4507                                          path, ar.len);
4508         if (!err)
4509                 err = ext4_ext_insert_extent(handle, inode, &path,
4510                                              &newex, flags);
4511
4512         if (err && free_on_err) {
4513                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4514                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4515                 /* free data blocks we just allocated */
4516                 /* not a good idea to call discard here directly,
4517                  * but otherwise we'd need to call it every free() */
4518                 ext4_discard_preallocations(inode);
4519                 ext4_free_blocks(handle, inode, NULL, newblock,
4520                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4521                 goto out2;
4522         }
4523
4524         /* previous routine could use block we allocated */
4525         newblock = ext4_ext_pblock(&newex);
4526         allocated = ext4_ext_get_actual_len(&newex);
4527         if (allocated > map->m_len)
4528                 allocated = map->m_len;
4529         map->m_flags |= EXT4_MAP_NEW;
4530
4531         /*
4532          * Update reserved blocks/metadata blocks after successful
4533          * block allocation which had been deferred till now.
4534          */
4535         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4536                 unsigned int reserved_clusters;
4537                 /*
4538                  * Check how many clusters we had reserved this allocated range
4539                  */
4540                 reserved_clusters = get_reserved_cluster_alloc(inode,
4541                                                 map->m_lblk, allocated);
4542                 if (!map_from_cluster) {
4543                         BUG_ON(allocated_clusters < reserved_clusters);
4544                         if (reserved_clusters < allocated_clusters) {
4545                                 struct ext4_inode_info *ei = EXT4_I(inode);
4546                                 int reservation = allocated_clusters -
4547                                                   reserved_clusters;
4548                                 /*
4549                                  * It seems we claimed few clusters outside of
4550                                  * the range of this allocation. We should give
4551                                  * it back to the reservation pool. This can
4552                                  * happen in the following case:
4553                                  *
4554                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4555                                  *   cluster has 4 blocks. Thus, the clusters
4556                                  *   are [0-3],[4-7],[8-11]...
4557                                  * * First comes delayed allocation write for
4558                                  *   logical blocks 10 & 11. Since there were no
4559                                  *   previous delayed allocated blocks in the
4560                                  *   range [8-11], we would reserve 1 cluster
4561                                  *   for this write.
4562                                  * * Next comes write for logical blocks 3 to 8.
4563                                  *   In this case, we will reserve 2 clusters
4564                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4565                                  *   that range has a delayed allocated blocks.
4566                                  *   Thus total reserved clusters now becomes 3.
4567                                  * * Now, during the delayed allocation writeout
4568                                  *   time, we will first write blocks [3-8] and
4569                                  *   allocate 3 clusters for writing these
4570                                  *   blocks. Also, we would claim all these
4571                                  *   three clusters above.
4572                                  * * Now when we come here to writeout the
4573                                  *   blocks [10-11], we would expect to claim
4574                                  *   the reservation of 1 cluster we had made
4575                                  *   (and we would claim it since there are no
4576                                  *   more delayed allocated blocks in the range
4577                                  *   [8-11]. But our reserved cluster count had
4578                                  *   already gone to 0.
4579                                  *
4580                                  *   Thus, at the step 4 above when we determine
4581                                  *   that there are still some unwritten delayed
4582                                  *   allocated blocks outside of our current
4583                                  *   block range, we should increment the
4584                                  *   reserved clusters count so that when the
4585                                  *   remaining blocks finally gets written, we
4586                                  *   could claim them.
4587                                  */
4588                                 dquot_reserve_block(inode,
4589                                                 EXT4_C2B(sbi, reservation));
4590                                 spin_lock(&ei->i_block_reservation_lock);
4591                                 ei->i_reserved_data_blocks += reservation;
4592                                 spin_unlock(&ei->i_block_reservation_lock);
4593                         }
4594                         /*
4595                          * We will claim quota for all newly allocated blocks.
4596                          * We're updating the reserved space *after* the
4597                          * correction above so we do not accidentally free
4598                          * all the metadata reservation because we might
4599                          * actually need it later on.
4600                          */
4601                         ext4_da_update_reserve_space(inode, allocated_clusters,
4602                                                         1);
4603                 }
4604         }
4605
4606         /*
4607          * Cache the extent and update transaction to commit on fdatasync only
4608          * when it is _not_ an unwritten extent.
4609          */
4610         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4611                 ext4_update_inode_fsync_trans(handle, inode, 1);
4612         else
4613                 ext4_update_inode_fsync_trans(handle, inode, 0);
4614 out:
4615         if (allocated > map->m_len)
4616                 allocated = map->m_len;
4617         ext4_ext_show_leaf(inode, path);
4618         map->m_flags |= EXT4_MAP_MAPPED;
4619         map->m_pblk = newblock;
4620         map->m_len = allocated;
4621 out2:
4622         ext4_ext_drop_refs(path);
4623         kfree(path);
4624
4625         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4626                                        err ? err : allocated);
4627         return err ? err : allocated;
4628 }
4629
4630 void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4631 {
4632         struct super_block *sb = inode->i_sb;
4633         ext4_lblk_t last_block;
4634         int err = 0;
4635
4636         /*
4637          * TODO: optimization is possible here.
4638          * Probably we need not scan at all,
4639          * because page truncation is enough.
4640          */
4641
4642         /* we have to know where to truncate from in crash case */
4643         EXT4_I(inode)->i_disksize = inode->i_size;
4644         ext4_mark_inode_dirty(handle, inode);
4645
4646         last_block = (inode->i_size + sb->s_blocksize - 1)
4647                         >> EXT4_BLOCK_SIZE_BITS(sb);
4648 retry:
4649         err = ext4_es_remove_extent(inode, last_block,
4650                                     EXT_MAX_BLOCKS - last_block);
4651         if (err == -ENOMEM) {
4652                 cond_resched();
4653                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4654                 goto retry;
4655         }
4656         if (err) {
4657                 ext4_std_error(inode->i_sb, err);
4658                 return;
4659         }
4660         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4661         ext4_std_error(inode->i_sb, err);
4662 }
4663
4664 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4665                                   ext4_lblk_t len, loff_t new_size,
4666                                   int flags, int mode)
4667 {
4668         struct inode *inode = file_inode(file);
4669         handle_t *handle;
4670         int ret = 0;
4671         int ret2 = 0;
4672         int retries = 0;
4673         int depth = 0;
4674         struct ext4_map_blocks map;
4675         unsigned int credits;
4676         loff_t epos;
4677
4678         map.m_lblk = offset;
4679         map.m_len = len;
4680         /*
4681          * Don't normalize the request if it can fit in one extent so
4682          * that it doesn't get unnecessarily split into multiple
4683          * extents.
4684          */
4685         if (len <= EXT_UNWRITTEN_MAX_LEN)
4686                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4687
4688         /*
4689          * credits to insert 1 extent into extent tree
4690          */
4691         credits = ext4_chunk_trans_blocks(inode, len);
4692         /*
4693          * We can only call ext_depth() on extent based inodes
4694          */
4695         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4696                 depth = ext_depth(inode);
4697         else
4698                 depth = -1;
4699
4700 retry:
4701         while (ret >= 0 && len) {
4702                 /*
4703                  * Recalculate credits when extent tree depth changes.
4704                  */
4705                 if (depth >= 0 && depth != ext_depth(inode)) {
4706                         credits = ext4_chunk_trans_blocks(inode, len);
4707                         depth = ext_depth(inode);
4708                 }
4709
4710                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4711                                             credits);
4712                 if (IS_ERR(handle)) {
4713                         ret = PTR_ERR(handle);
4714                         break;
4715                 }
4716                 ret = ext4_map_blocks(handle, inode, &map, flags);
4717                 if (ret <= 0) {
4718                         ext4_debug("inode #%lu: block %u: len %u: "
4719                                    "ext4_ext_map_blocks returned %d",
4720                                    inode->i_ino, map.m_lblk,
4721                                    map.m_len, ret);
4722                         ext4_mark_inode_dirty(handle, inode);
4723                         ret2 = ext4_journal_stop(handle);
4724                         break;
4725                 }
4726                 map.m_lblk += ret;
4727                 map.m_len = len = len - ret;
4728                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4729                 inode->i_ctime = ext4_current_time(inode);
4730                 if (new_size) {
4731                         if (epos > new_size)
4732                                 epos = new_size;
4733                         if (ext4_update_inode_size(inode, epos) & 0x1)
4734                                 inode->i_mtime = inode->i_ctime;
4735                 } else {
4736                         if (epos > inode->i_size)
4737                                 ext4_set_inode_flag(inode,
4738                                                     EXT4_INODE_EOFBLOCKS);
4739                 }
4740                 ext4_mark_inode_dirty(handle, inode);
4741                 ret2 = ext4_journal_stop(handle);
4742                 if (ret2)
4743                         break;
4744         }
4745         if (ret == -ENOSPC &&
4746                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4747                 ret = 0;
4748                 goto retry;
4749         }
4750
4751         return ret > 0 ? ret2 : ret;
4752 }
4753
4754 static long ext4_zero_range(struct file *file, loff_t offset,
4755                             loff_t len, int mode)
4756 {
4757         struct inode *inode = file_inode(file);
4758         handle_t *handle = NULL;
4759         unsigned int max_blocks;
4760         loff_t new_size = 0;
4761         int ret = 0;
4762         int flags;
4763         int credits;
4764         int partial_begin, partial_end;
4765         loff_t start, end;
4766         ext4_lblk_t lblk;
4767         unsigned int blkbits = inode->i_blkbits;
4768
4769         trace_ext4_zero_range(inode, offset, len, mode);
4770
4771         if (!S_ISREG(inode->i_mode))
4772                 return -EINVAL;
4773
4774         /* Call ext4_force_commit to flush all data in case of data=journal. */
4775         if (ext4_should_journal_data(inode)) {
4776                 ret = ext4_force_commit(inode->i_sb);
4777                 if (ret)
4778                         return ret;
4779         }
4780
4781         /*
4782          * Round up offset. This is not fallocate, we neet to zero out
4783          * blocks, so convert interior block aligned part of the range to
4784          * unwritten and possibly manually zero out unaligned parts of the
4785          * range.
4786          */
4787         start = round_up(offset, 1 << blkbits);
4788         end = round_down((offset + len), 1 << blkbits);
4789
4790         if (start < offset || end > offset + len)
4791                 return -EINVAL;
4792         partial_begin = offset & ((1 << blkbits) - 1);
4793         partial_end = (offset + len) & ((1 << blkbits) - 1);
4794
4795         lblk = start >> blkbits;
4796         max_blocks = (end >> blkbits);
4797         if (max_blocks < lblk)
4798                 max_blocks = 0;
4799         else
4800                 max_blocks -= lblk;
4801
4802         inode_lock(inode);
4803
4804         /*
4805          * Indirect files do not support unwritten extnets
4806          */
4807         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4808                 ret = -EOPNOTSUPP;
4809                 goto out_mutex;
4810         }
4811
4812         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4813              offset + len > i_size_read(inode)) {
4814                 new_size = offset + len;
4815                 ret = inode_newsize_ok(inode, new_size);
4816                 if (ret)
4817                         goto out_mutex;
4818         }
4819
4820         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4821         if (mode & FALLOC_FL_KEEP_SIZE)
4822                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4823
4824         /* Wait all existing dio workers, newcomers will block on i_mutex */
4825         ext4_inode_block_unlocked_dio(inode);
4826         inode_dio_wait(inode);
4827
4828         /* Preallocate the range including the unaligned edges */
4829         if (partial_begin || partial_end) {
4830                 ret = ext4_alloc_file_blocks(file,
4831                                 round_down(offset, 1 << blkbits) >> blkbits,
4832                                 (round_up((offset + len), 1 << blkbits) -
4833                                  round_down(offset, 1 << blkbits)) >> blkbits,
4834                                 new_size, flags, mode);
4835                 if (ret)
4836                         goto out_dio;
4837
4838         }
4839
4840         /* Zero range excluding the unaligned edges */
4841         if (max_blocks > 0) {
4842                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4843                           EXT4_EX_NOCACHE);
4844
4845                 /*
4846                  * Prevent page faults from reinstantiating pages we have
4847                  * released from page cache.
4848                  */
4849                 down_write(&EXT4_I(inode)->i_mmap_sem);
4850                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4851                 if (ret) {
4852                         up_write(&EXT4_I(inode)->i_mmap_sem);
4853                         goto out_dio;
4854                 }
4855                 /* Now release the pages and zero block aligned part of pages */
4856                 truncate_pagecache_range(inode, start, end - 1);
4857                 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4858
4859                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4860                                              flags, mode);
4861                 up_write(&EXT4_I(inode)->i_mmap_sem);
4862                 if (ret)
4863                         goto out_dio;
4864         }
4865         if (!partial_begin && !partial_end)
4866                 goto out_dio;
4867
4868         /*
4869          * In worst case we have to writeout two nonadjacent unwritten
4870          * blocks and update the inode
4871          */
4872         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4873         if (ext4_should_journal_data(inode))
4874                 credits += 2;
4875         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4876         if (IS_ERR(handle)) {
4877                 ret = PTR_ERR(handle);
4878                 ext4_std_error(inode->i_sb, ret);
4879                 goto out_dio;
4880         }
4881
4882         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4883         if (new_size) {
4884                 ext4_update_inode_size(inode, new_size);
4885         } else {
4886                 /*
4887                 * Mark that we allocate beyond EOF so the subsequent truncate
4888                 * can proceed even if the new size is the same as i_size.
4889                 */
4890                 if ((offset + len) > i_size_read(inode))
4891                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4892         }
4893         ext4_mark_inode_dirty(handle, inode);
4894
4895         /* Zero out partial block at the edges of the range */
4896         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4897
4898         if (file->f_flags & O_SYNC)
4899                 ext4_handle_sync(handle);
4900
4901         ext4_journal_stop(handle);
4902 out_dio:
4903         ext4_inode_resume_unlocked_dio(inode);
4904 out_mutex:
4905         inode_unlock(inode);
4906         return ret;
4907 }
4908
4909 /*
4910  * preallocate space for a file. This implements ext4's fallocate file
4911  * operation, which gets called from sys_fallocate system call.
4912  * For block-mapped files, posix_fallocate should fall back to the method
4913  * of writing zeroes to the required new blocks (the same behavior which is
4914  * expected for file systems which do not support fallocate() system call).
4915  */
4916 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4917 {
4918         struct inode *inode = file_inode(file);
4919         loff_t new_size = 0;
4920         unsigned int max_blocks;
4921         int ret = 0;
4922         int flags;
4923         ext4_lblk_t lblk;
4924         unsigned int blkbits = inode->i_blkbits;
4925
4926         /*
4927          * Encrypted inodes can't handle collapse range or insert
4928          * range since we would need to re-encrypt blocks with a
4929          * different IV or XTS tweak (which are based on the logical
4930          * block number).
4931          *
4932          * XXX It's not clear why zero range isn't working, but we'll
4933          * leave it disabled for encrypted inodes for now.  This is a
4934          * bug we should fix....
4935          */
4936         if (ext4_encrypted_inode(inode) &&
4937             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4938                      FALLOC_FL_ZERO_RANGE)))
4939                 return -EOPNOTSUPP;
4940
4941         /* Return error if mode is not supported */
4942         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4943                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4944                      FALLOC_FL_INSERT_RANGE))
4945                 return -EOPNOTSUPP;
4946
4947         if (mode & FALLOC_FL_PUNCH_HOLE)
4948                 return ext4_punch_hole(inode, offset, len);
4949
4950         ret = ext4_convert_inline_data(inode);
4951         if (ret)
4952                 return ret;
4953
4954         if (mode & FALLOC_FL_COLLAPSE_RANGE)
4955                 return ext4_collapse_range(inode, offset, len);
4956
4957         if (mode & FALLOC_FL_INSERT_RANGE)
4958                 return ext4_insert_range(inode, offset, len);
4959
4960         if (mode & FALLOC_FL_ZERO_RANGE)
4961                 return ext4_zero_range(file, offset, len, mode);
4962
4963         trace_ext4_fallocate_enter(inode, offset, len, mode);
4964         lblk = offset >> blkbits;
4965         /*
4966          * We can't just convert len to max_blocks because
4967          * If blocksize = 4096 offset = 3072 and len = 2048
4968          */
4969         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4970                 - lblk;
4971
4972         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4973         if (mode & FALLOC_FL_KEEP_SIZE)
4974                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4975
4976         inode_lock(inode);
4977
4978         /*
4979          * We only support preallocation for extent-based files only
4980          */
4981         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4982                 ret = -EOPNOTSUPP;
4983                 goto out;
4984         }
4985
4986         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4987              offset + len > i_size_read(inode)) {
4988                 new_size = offset + len;
4989                 ret = inode_newsize_ok(inode, new_size);
4990                 if (ret)
4991                         goto out;
4992         }
4993
4994         /* Wait all existing dio workers, newcomers will block on i_mutex */
4995         ext4_inode_block_unlocked_dio(inode);
4996         inode_dio_wait(inode);
4997
4998         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4999                                      flags, mode);
5000         ext4_inode_resume_unlocked_dio(inode);
5001         if (ret)
5002                 goto out;
5003
5004         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
5005                 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
5006                                                 EXT4_I(inode)->i_sync_tid);
5007         }
5008 out:
5009         inode_unlock(inode);
5010         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
5011         return ret;
5012 }
5013
5014 /*
5015  * This function convert a range of blocks to written extents
5016  * The caller of this function will pass the start offset and the size.
5017  * all unwritten extents within this range will be converted to
5018  * written extents.
5019  *
5020  * This function is called from the direct IO end io call back
5021  * function, to convert the fallocated extents after IO is completed.
5022  * Returns 0 on success.
5023  */
5024 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
5025                                    loff_t offset, ssize_t len)
5026 {
5027         unsigned int max_blocks;
5028         int ret = 0;
5029         int ret2 = 0;
5030         struct ext4_map_blocks map;
5031         unsigned int credits, blkbits = inode->i_blkbits;
5032
5033         map.m_lblk = offset >> blkbits;
5034         /*
5035          * We can't just convert len to max_blocks because
5036          * If blocksize = 4096 offset = 3072 and len = 2048
5037          */
5038         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
5039                       map.m_lblk);
5040         /*
5041          * This is somewhat ugly but the idea is clear: When transaction is
5042          * reserved, everything goes into it. Otherwise we rather start several
5043          * smaller transactions for conversion of each extent separately.
5044          */
5045         if (handle) {
5046                 handle = ext4_journal_start_reserved(handle,
5047                                                      EXT4_HT_EXT_CONVERT);
5048                 if (IS_ERR(handle))
5049                         return PTR_ERR(handle);
5050                 credits = 0;
5051         } else {
5052                 /*
5053                  * credits to insert 1 extent into extent tree
5054                  */
5055                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5056         }
5057         while (ret >= 0 && ret < max_blocks) {
5058                 map.m_lblk += ret;
5059                 map.m_len = (max_blocks -= ret);
5060                 if (credits) {
5061                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5062                                                     credits);
5063                         if (IS_ERR(handle)) {
5064                                 ret = PTR_ERR(handle);
5065                                 break;
5066                         }
5067                 }
5068                 ret = ext4_map_blocks(handle, inode, &map,
5069                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5070                 if (ret <= 0)
5071                         ext4_warning(inode->i_sb,
5072                                      "inode #%lu: block %u: len %u: "
5073                                      "ext4_ext_map_blocks returned %d",
5074                                      inode->i_ino, map.m_lblk,
5075                                      map.m_len, ret);
5076                 ext4_mark_inode_dirty(handle, inode);
5077                 if (credits)
5078                         ret2 = ext4_journal_stop(handle);
5079                 if (ret <= 0 || ret2)
5080                         break;
5081         }
5082         if (!credits)
5083                 ret2 = ext4_journal_stop(handle);
5084         return ret > 0 ? ret2 : ret;
5085 }
5086
5087 /*
5088  * If newes is not existing extent (newes->ec_pblk equals zero) find
5089  * delayed extent at start of newes and update newes accordingly and
5090  * return start of the next delayed extent.
5091  *
5092  * If newes is existing extent (newes->ec_pblk is not equal zero)
5093  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5094  * extent found. Leave newes unmodified.
5095  */
5096 static int ext4_find_delayed_extent(struct inode *inode,
5097                                     struct extent_status *newes)
5098 {
5099         struct extent_status es;
5100         ext4_lblk_t block, next_del;
5101
5102         if (newes->es_pblk == 0) {
5103                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5104                                 newes->es_lblk + newes->es_len - 1, &es);
5105
5106                 /*
5107                  * No extent in extent-tree contains block @newes->es_pblk,
5108                  * then the block may stay in 1)a hole or 2)delayed-extent.
5109                  */
5110                 if (es.es_len == 0)
5111                         /* A hole found. */
5112                         return 0;
5113
5114                 if (es.es_lblk > newes->es_lblk) {
5115                         /* A hole found. */
5116                         newes->es_len = min(es.es_lblk - newes->es_lblk,
5117                                             newes->es_len);
5118                         return 0;
5119                 }
5120
5121                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5122         }
5123
5124         block = newes->es_lblk + newes->es_len;
5125         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5126         if (es.es_len == 0)
5127                 next_del = EXT_MAX_BLOCKS;
5128         else
5129                 next_del = es.es_lblk;
5130
5131         return next_del;
5132 }
5133 /* fiemap flags we can handle specified here */
5134 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5135
5136 static int ext4_xattr_fiemap(struct inode *inode,
5137                                 struct fiemap_extent_info *fieinfo)
5138 {
5139         __u64 physical = 0;
5140         __u64 length;
5141         __u32 flags = FIEMAP_EXTENT_LAST;
5142         int blockbits = inode->i_sb->s_blocksize_bits;
5143         int error = 0;
5144
5145         /* in-inode? */
5146         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5147                 struct ext4_iloc iloc;
5148                 int offset;     /* offset of xattr in inode */
5149
5150                 error = ext4_get_inode_loc(inode, &iloc);
5151                 if (error)
5152                         return error;
5153                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5154                 offset = EXT4_GOOD_OLD_INODE_SIZE +
5155                                 EXT4_I(inode)->i_extra_isize;
5156                 physical += offset;
5157                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5158                 flags |= FIEMAP_EXTENT_DATA_INLINE;
5159                 brelse(iloc.bh);
5160         } else { /* external block */
5161                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5162                 length = inode->i_sb->s_blocksize;
5163         }
5164
5165         if (physical)
5166                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5167                                                 length, flags);
5168         return (error < 0 ? error : 0);
5169 }
5170
5171 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5172                 __u64 start, __u64 len)
5173 {
5174         ext4_lblk_t start_blk;
5175         int error = 0;
5176
5177         if (ext4_has_inline_data(inode)) {
5178                 int has_inline = 1;
5179
5180                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5181                                                 start, len);
5182
5183                 if (has_inline)
5184                         return error;
5185         }
5186
5187         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5188                 error = ext4_ext_precache(inode);
5189                 if (error)
5190                         return error;
5191         }
5192
5193         /* fallback to generic here if not in extents fmt */
5194         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5195                 return generic_block_fiemap(inode, fieinfo, start, len,
5196                         ext4_get_block);
5197
5198         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5199                 return -EBADR;
5200
5201         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5202                 error = ext4_xattr_fiemap(inode, fieinfo);
5203         } else {
5204                 ext4_lblk_t len_blks;
5205                 __u64 last_blk;
5206
5207                 start_blk = start >> inode->i_sb->s_blocksize_bits;
5208                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5209                 if (last_blk >= EXT_MAX_BLOCKS)
5210                         last_blk = EXT_MAX_BLOCKS-1;
5211                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5212
5213                 /*
5214                  * Walk the extent tree gathering extent information
5215                  * and pushing extents back to the user.
5216                  */
5217                 error = ext4_fill_fiemap_extents(inode, start_blk,
5218                                                  len_blks, fieinfo);
5219         }
5220         return error;
5221 }
5222
5223 /*
5224  * ext4_access_path:
5225  * Function to access the path buffer for marking it dirty.
5226  * It also checks if there are sufficient credits left in the journal handle
5227  * to update path.
5228  */
5229 static int
5230 ext4_access_path(handle_t *handle, struct inode *inode,
5231                 struct ext4_ext_path *path)
5232 {
5233         int credits, err;
5234
5235         if (!ext4_handle_valid(handle))
5236                 return 0;
5237
5238         /*
5239          * Check if need to extend journal credits
5240          * 3 for leaf, sb, and inode plus 2 (bmap and group
5241          * descriptor) for each block group; assume two block
5242          * groups
5243          */
5244         if (handle->h_buffer_credits < 7) {
5245                 credits = ext4_writepage_trans_blocks(inode);
5246                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5247                 /* EAGAIN is success */
5248                 if (err && err != -EAGAIN)
5249                         return err;
5250         }
5251
5252         err = ext4_ext_get_access(handle, inode, path);
5253         return err;
5254 }
5255
5256 /*
5257  * ext4_ext_shift_path_extents:
5258  * Shift the extents of a path structure lying between path[depth].p_ext
5259  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5260  * if it is right shift or left shift operation.
5261  */
5262 static int
5263 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5264                             struct inode *inode, handle_t *handle,
5265                             enum SHIFT_DIRECTION SHIFT)
5266 {
5267         int depth, err = 0;
5268         struct ext4_extent *ex_start, *ex_last;
5269         bool update = 0;
5270         depth = path->p_depth;
5271
5272         while (depth >= 0) {
5273                 if (depth == path->p_depth) {
5274                         ex_start = path[depth].p_ext;
5275                         if (!ex_start)
5276                                 return -EFSCORRUPTED;
5277
5278                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5279
5280                         err = ext4_access_path(handle, inode, path + depth);
5281                         if (err)
5282                                 goto out;
5283
5284                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5285                                 update = 1;
5286
5287                         while (ex_start <= ex_last) {
5288                                 if (SHIFT == SHIFT_LEFT) {
5289                                         le32_add_cpu(&ex_start->ee_block,
5290                                                 -shift);
5291                                         /* Try to merge to the left. */
5292                                         if ((ex_start >
5293                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5294                                             &&
5295                                             ext4_ext_try_to_merge_right(inode,
5296                                             path, ex_start - 1))
5297                                                 ex_last--;
5298                                         else
5299                                                 ex_start++;
5300                                 } else {
5301                                         le32_add_cpu(&ex_last->ee_block, shift);
5302                                         ext4_ext_try_to_merge_right(inode, path,
5303                                                 ex_last);
5304                                         ex_last--;
5305                                 }
5306                         }
5307                         err = ext4_ext_dirty(handle, inode, path + depth);
5308                         if (err)
5309                                 goto out;
5310
5311                         if (--depth < 0 || !update)
5312                                 break;
5313                 }
5314
5315                 /* Update index too */
5316                 err = ext4_access_path(handle, inode, path + depth);
5317                 if (err)
5318                         goto out;
5319
5320                 if (SHIFT == SHIFT_LEFT)
5321                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5322                 else
5323                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5324                 err = ext4_ext_dirty(handle, inode, path + depth);
5325                 if (err)
5326                         goto out;
5327
5328                 /* we are done if current index is not a starting index */
5329                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5330                         break;
5331
5332                 depth--;
5333         }
5334
5335 out:
5336         return err;
5337 }
5338
5339 /*
5340  * ext4_ext_shift_extents:
5341  * All the extents which lies in the range from @start to the last allocated
5342  * block for the @inode are shifted either towards left or right (depending
5343  * upon @SHIFT) by @shift blocks.
5344  * On success, 0 is returned, error otherwise.
5345  */
5346 static int
5347 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5348                        ext4_lblk_t start, ext4_lblk_t shift,
5349                        enum SHIFT_DIRECTION SHIFT)
5350 {
5351         struct ext4_ext_path *path;
5352         int ret = 0, depth;
5353         struct ext4_extent *extent;
5354         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5355
5356         /* Let path point to the last extent */
5357         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
5358         if (IS_ERR(path))
5359                 return PTR_ERR(path);
5360
5361         depth = path->p_depth;
5362         extent = path[depth].p_ext;
5363         if (!extent)
5364                 goto out;
5365
5366         stop = le32_to_cpu(extent->ee_block) +
5367                         ext4_ext_get_actual_len(extent);
5368
5369        /*
5370          * In case of left shift, Don't start shifting extents until we make
5371          * sure the hole is big enough to accommodate the shift.
5372         */
5373         if (SHIFT == SHIFT_LEFT) {
5374                 path = ext4_find_extent(inode, start - 1, &path, 0);
5375                 if (IS_ERR(path))
5376                         return PTR_ERR(path);
5377                 depth = path->p_depth;
5378                 extent =  path[depth].p_ext;
5379                 if (extent) {
5380                         ex_start = le32_to_cpu(extent->ee_block);
5381                         ex_end = le32_to_cpu(extent->ee_block) +
5382                                 ext4_ext_get_actual_len(extent);
5383                 } else {
5384                         ex_start = 0;
5385                         ex_end = 0;
5386                 }
5387
5388                 if ((start == ex_start && shift > ex_start) ||
5389                     (shift > start - ex_end)) {
5390                         ext4_ext_drop_refs(path);
5391                         kfree(path);
5392                         return -EINVAL;
5393                 }
5394         }
5395
5396         /*
5397          * In case of left shift, iterator points to start and it is increased
5398          * till we reach stop. In case of right shift, iterator points to stop
5399          * and it is decreased till we reach start.
5400          */
5401         if (SHIFT == SHIFT_LEFT)
5402                 iterator = &start;
5403         else
5404                 iterator = &stop;
5405
5406         /* Its safe to start updating extents */
5407         while (start < stop) {
5408                 path = ext4_find_extent(inode, *iterator, &path, 0);
5409                 if (IS_ERR(path))
5410                         return PTR_ERR(path);
5411                 depth = path->p_depth;
5412                 extent = path[depth].p_ext;
5413                 if (!extent) {
5414                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5415                                          (unsigned long) *iterator);
5416                         return -EFSCORRUPTED;
5417                 }
5418                 if (SHIFT == SHIFT_LEFT && *iterator >
5419                     le32_to_cpu(extent->ee_block)) {
5420                         /* Hole, move to the next extent */
5421                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5422                                 path[depth].p_ext++;
5423                         } else {
5424                                 *iterator = ext4_ext_next_allocated_block(path);
5425                                 continue;
5426                         }
5427                 }
5428
5429                 if (SHIFT == SHIFT_LEFT) {
5430                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5431                         *iterator = le32_to_cpu(extent->ee_block) +
5432                                         ext4_ext_get_actual_len(extent);
5433                 } else {
5434                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5435                         *iterator =  le32_to_cpu(extent->ee_block) > 0 ?
5436                                 le32_to_cpu(extent->ee_block) - 1 : 0;
5437                         /* Update path extent in case we need to stop */
5438                         while (le32_to_cpu(extent->ee_block) < start)
5439                                 extent++;
5440                         path[depth].p_ext = extent;
5441                 }
5442                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5443                                 handle, SHIFT);
5444                 if (ret)
5445                         break;
5446         }
5447 out:
5448         ext4_ext_drop_refs(path);
5449         kfree(path);
5450         return ret;
5451 }
5452
5453 /*
5454  * ext4_collapse_range:
5455  * This implements the fallocate's collapse range functionality for ext4
5456  * Returns: 0 and non-zero on error.
5457  */
5458 int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5459 {
5460         struct super_block *sb = inode->i_sb;
5461         ext4_lblk_t punch_start, punch_stop;
5462         handle_t *handle;
5463         unsigned int credits;
5464         loff_t new_size, ioffset;
5465         int ret;
5466
5467         /*
5468          * We need to test this early because xfstests assumes that a
5469          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5470          * system does not support collapse range.
5471          */
5472         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5473                 return -EOPNOTSUPP;
5474
5475         /* Collapse range works only on fs block size aligned offsets. */
5476         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5477             len & (EXT4_CLUSTER_SIZE(sb) - 1))
5478                 return -EINVAL;
5479
5480         if (!S_ISREG(inode->i_mode))
5481                 return -EINVAL;
5482
5483         trace_ext4_collapse_range(inode, offset, len);
5484
5485         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5486         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5487
5488         /* Call ext4_force_commit to flush all data in case of data=journal. */
5489         if (ext4_should_journal_data(inode)) {
5490                 ret = ext4_force_commit(inode->i_sb);
5491                 if (ret)
5492                         return ret;
5493         }
5494
5495         inode_lock(inode);
5496         /*
5497          * There is no need to overlap collapse range with EOF, in which case
5498          * it is effectively a truncate operation
5499          */
5500         if (offset + len >= i_size_read(inode)) {
5501                 ret = -EINVAL;
5502                 goto out_mutex;
5503         }
5504
5505         /* Currently just for extent based files */
5506         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5507                 ret = -EOPNOTSUPP;
5508                 goto out_mutex;
5509         }
5510
5511         /* Wait for existing dio to complete */
5512         ext4_inode_block_unlocked_dio(inode);
5513         inode_dio_wait(inode);
5514
5515         /*
5516          * Prevent page faults from reinstantiating pages we have released from
5517          * page cache.
5518          */
5519         down_write(&EXT4_I(inode)->i_mmap_sem);
5520         /*
5521          * Need to round down offset to be aligned with page size boundary
5522          * for page size > block size.
5523          */
5524         ioffset = round_down(offset, PAGE_SIZE);
5525         /*
5526          * Write tail of the last page before removed range since it will get
5527          * removed from the page cache below.
5528          */
5529         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5530         if (ret)
5531                 goto out_mmap;
5532         /*
5533          * Write data that will be shifted to preserve them when discarding
5534          * page cache below. We are also protected from pages becoming dirty
5535          * by i_mmap_sem.
5536          */
5537         ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5538                                            LLONG_MAX);
5539         if (ret)
5540                 goto out_mmap;
5541         truncate_pagecache(inode, ioffset);
5542
5543         credits = ext4_writepage_trans_blocks(inode);
5544         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5545         if (IS_ERR(handle)) {
5546                 ret = PTR_ERR(handle);
5547                 goto out_mmap;
5548         }
5549
5550         down_write(&EXT4_I(inode)->i_data_sem);
5551         ext4_discard_preallocations(inode);
5552
5553         ret = ext4_es_remove_extent(inode, punch_start,
5554                                     EXT_MAX_BLOCKS - punch_start);
5555         if (ret) {
5556                 up_write(&EXT4_I(inode)->i_data_sem);
5557                 goto out_stop;
5558         }
5559
5560         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5561         if (ret) {
5562                 up_write(&EXT4_I(inode)->i_data_sem);
5563                 goto out_stop;
5564         }
5565         ext4_discard_preallocations(inode);
5566
5567         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5568                                      punch_stop - punch_start, SHIFT_LEFT);
5569         if (ret) {
5570                 up_write(&EXT4_I(inode)->i_data_sem);
5571                 goto out_stop;
5572         }
5573
5574         new_size = i_size_read(inode) - len;
5575         i_size_write(inode, new_size);
5576         EXT4_I(inode)->i_disksize = new_size;
5577
5578         up_write(&EXT4_I(inode)->i_data_sem);
5579         if (IS_SYNC(inode))
5580                 ext4_handle_sync(handle);
5581         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5582         ext4_mark_inode_dirty(handle, inode);
5583
5584 out_stop:
5585         ext4_journal_stop(handle);
5586 out_mmap:
5587         up_write(&EXT4_I(inode)->i_mmap_sem);
5588         ext4_inode_resume_unlocked_dio(inode);
5589 out_mutex:
5590         inode_unlock(inode);
5591         return ret;
5592 }
5593
5594 /*
5595  * ext4_insert_range:
5596  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5597  * The data blocks starting from @offset to the EOF are shifted by @len
5598  * towards right to create a hole in the @inode. Inode size is increased
5599  * by len bytes.
5600  * Returns 0 on success, error otherwise.
5601  */
5602 int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5603 {
5604         struct super_block *sb = inode->i_sb;
5605         handle_t *handle;
5606         struct ext4_ext_path *path;
5607         struct ext4_extent *extent;
5608         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5609         unsigned int credits, ee_len;
5610         int ret = 0, depth, split_flag = 0;
5611         loff_t ioffset;
5612
5613         /*
5614          * We need to test this early because xfstests assumes that an
5615          * insert range of (0, 1) will return EOPNOTSUPP if the file
5616          * system does not support insert range.
5617          */
5618         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5619                 return -EOPNOTSUPP;
5620
5621         /* Insert range works only on fs block size aligned offsets. */
5622         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5623                         len & (EXT4_CLUSTER_SIZE(sb) - 1))
5624                 return -EINVAL;
5625
5626         if (!S_ISREG(inode->i_mode))
5627                 return -EOPNOTSUPP;
5628
5629         trace_ext4_insert_range(inode, offset, len);
5630
5631         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5632         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5633
5634         /* Call ext4_force_commit to flush all data in case of data=journal */
5635         if (ext4_should_journal_data(inode)) {
5636                 ret = ext4_force_commit(inode->i_sb);
5637                 if (ret)
5638                         return ret;
5639         }
5640
5641         inode_lock(inode);
5642         /* Currently just for extent based files */
5643         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5644                 ret = -EOPNOTSUPP;
5645                 goto out_mutex;
5646         }
5647
5648         /* Check for wrap through zero */
5649         if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5650                 ret = -EFBIG;
5651                 goto out_mutex;
5652         }
5653
5654         /* Offset should be less than i_size */
5655         if (offset >= i_size_read(inode)) {
5656                 ret = -EINVAL;
5657                 goto out_mutex;
5658         }
5659
5660         /* Wait for existing dio to complete */
5661         ext4_inode_block_unlocked_dio(inode);
5662         inode_dio_wait(inode);
5663
5664         /*
5665          * Prevent page faults from reinstantiating pages we have released from
5666          * page cache.
5667          */
5668         down_write(&EXT4_I(inode)->i_mmap_sem);
5669         /*
5670          * Need to round down to align start offset to page size boundary
5671          * for page size > block size.
5672          */
5673         ioffset = round_down(offset, PAGE_SIZE);
5674         /* Write out all dirty pages */
5675         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5676                         LLONG_MAX);
5677         if (ret)
5678                 goto out_mmap;
5679         truncate_pagecache(inode, ioffset);
5680
5681         credits = ext4_writepage_trans_blocks(inode);
5682         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5683         if (IS_ERR(handle)) {
5684                 ret = PTR_ERR(handle);
5685                 goto out_mmap;
5686         }
5687
5688         /* Expand file to avoid data loss if there is error while shifting */
5689         inode->i_size += len;
5690         EXT4_I(inode)->i_disksize += len;
5691         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5692         ret = ext4_mark_inode_dirty(handle, inode);
5693         if (ret)
5694                 goto out_stop;
5695
5696         down_write(&EXT4_I(inode)->i_data_sem);
5697         ext4_discard_preallocations(inode);
5698
5699         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5700         if (IS_ERR(path)) {
5701                 up_write(&EXT4_I(inode)->i_data_sem);
5702                 goto out_stop;
5703         }
5704
5705         depth = ext_depth(inode);
5706         extent = path[depth].p_ext;
5707         if (extent) {
5708                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5709                 ee_len = ext4_ext_get_actual_len(extent);
5710
5711                 /*
5712                  * If offset_lblk is not the starting block of extent, split
5713                  * the extent @offset_lblk
5714                  */
5715                 if ((offset_lblk > ee_start_lblk) &&
5716                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5717                         if (ext4_ext_is_unwritten(extent))
5718                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5719                                         EXT4_EXT_MARK_UNWRIT2;
5720                         ret = ext4_split_extent_at(handle, inode, &path,
5721                                         offset_lblk, split_flag,
5722                                         EXT4_EX_NOCACHE |
5723                                         EXT4_GET_BLOCKS_PRE_IO |
5724                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5725                 }
5726
5727                 ext4_ext_drop_refs(path);
5728                 kfree(path);
5729                 if (ret < 0) {
5730                         up_write(&EXT4_I(inode)->i_data_sem);
5731                         goto out_stop;
5732                 }
5733         }
5734
5735         ret = ext4_es_remove_extent(inode, offset_lblk,
5736                         EXT_MAX_BLOCKS - offset_lblk);
5737         if (ret) {
5738                 up_write(&EXT4_I(inode)->i_data_sem);
5739                 goto out_stop;
5740         }
5741
5742         /*
5743          * if offset_lblk lies in a hole which is at start of file, use
5744          * ee_start_lblk to shift extents
5745          */
5746         ret = ext4_ext_shift_extents(inode, handle,
5747                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5748                 len_lblk, SHIFT_RIGHT);
5749
5750         up_write(&EXT4_I(inode)->i_data_sem);
5751         if (IS_SYNC(inode))
5752                 ext4_handle_sync(handle);
5753
5754 out_stop:
5755         ext4_journal_stop(handle);
5756 out_mmap:
5757         up_write(&EXT4_I(inode)->i_mmap_sem);
5758         ext4_inode_resume_unlocked_dio(inode);
5759 out_mutex:
5760         inode_unlock(inode);
5761         return ret;
5762 }
5763
5764 /**
5765  * ext4_swap_extents - Swap extents between two inodes
5766  *
5767  * @inode1:     First inode
5768  * @inode2:     Second inode
5769  * @lblk1:      Start block for first inode
5770  * @lblk2:      Start block for second inode
5771  * @count:      Number of blocks to swap
5772  * @mark_unwritten: Mark second inode's extents as unwritten after swap
5773  * @erp:        Pointer to save error value
5774  *
5775  * This helper routine does exactly what is promise "swap extents". All other
5776  * stuff such as page-cache locking consistency, bh mapping consistency or
5777  * extent's data copying must be performed by caller.
5778  * Locking:
5779  *              i_mutex is held for both inodes
5780  *              i_data_sem is locked for write for both inodes
5781  * Assumptions:
5782  *              All pages from requested range are locked for both inodes
5783  */
5784 int
5785 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5786                      struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5787                   ext4_lblk_t count, int unwritten, int *erp)
5788 {
5789         struct ext4_ext_path *path1 = NULL;
5790         struct ext4_ext_path *path2 = NULL;
5791         int replaced_count = 0;
5792
5793         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5794         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5795         BUG_ON(!inode_is_locked(inode1));
5796         BUG_ON(!inode_is_locked(inode2));
5797
5798         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5799         if (unlikely(*erp))
5800                 return 0;
5801         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5802         if (unlikely(*erp))
5803                 return 0;
5804
5805         while (count) {
5806                 struct ext4_extent *ex1, *ex2, tmp_ex;
5807                 ext4_lblk_t e1_blk, e2_blk;
5808                 int e1_len, e2_len, len;
5809                 int split = 0;
5810
5811                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5812                 if (IS_ERR(path1)) {
5813                         *erp = PTR_ERR(path1);
5814                         path1 = NULL;
5815                 finish:
5816                         count = 0;
5817                         goto repeat;
5818                 }
5819                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5820                 if (IS_ERR(path2)) {
5821                         *erp = PTR_ERR(path2);
5822                         path2 = NULL;
5823                         goto finish;
5824                 }
5825                 ex1 = path1[path1->p_depth].p_ext;
5826                 ex2 = path2[path2->p_depth].p_ext;
5827                 /* Do we have somthing to swap ? */
5828                 if (unlikely(!ex2 || !ex1))
5829                         goto finish;
5830
5831                 e1_blk = le32_to_cpu(ex1->ee_block);
5832                 e2_blk = le32_to_cpu(ex2->ee_block);
5833                 e1_len = ext4_ext_get_actual_len(ex1);
5834                 e2_len = ext4_ext_get_actual_len(ex2);
5835
5836                 /* Hole handling */
5837                 if (!in_range(lblk1, e1_blk, e1_len) ||
5838                     !in_range(lblk2, e2_blk, e2_len)) {
5839                         ext4_lblk_t next1, next2;
5840
5841                         /* if hole after extent, then go to next extent */
5842                         next1 = ext4_ext_next_allocated_block(path1);
5843                         next2 = ext4_ext_next_allocated_block(path2);
5844                         /* If hole before extent, then shift to that extent */
5845                         if (e1_blk > lblk1)
5846                                 next1 = e1_blk;
5847                         if (e2_blk > lblk2)
5848                                 next2 = e1_blk;
5849                         /* Do we have something to swap */
5850                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5851                                 goto finish;
5852                         /* Move to the rightest boundary */
5853                         len = next1 - lblk1;
5854                         if (len < next2 - lblk2)
5855                                 len = next2 - lblk2;
5856                         if (len > count)
5857                                 len = count;
5858                         lblk1 += len;
5859                         lblk2 += len;
5860                         count -= len;
5861                         goto repeat;
5862                 }
5863
5864                 /* Prepare left boundary */
5865                 if (e1_blk < lblk1) {
5866                         split = 1;
5867                         *erp = ext4_force_split_extent_at(handle, inode1,
5868                                                 &path1, lblk1, 0);
5869                         if (unlikely(*erp))
5870                                 goto finish;
5871                 }
5872                 if (e2_blk < lblk2) {
5873                         split = 1;
5874                         *erp = ext4_force_split_extent_at(handle, inode2,
5875                                                 &path2,  lblk2, 0);
5876                         if (unlikely(*erp))
5877                                 goto finish;
5878                 }
5879                 /* ext4_split_extent_at() may result in leaf extent split,
5880                  * path must to be revalidated. */
5881                 if (split)
5882                         goto repeat;
5883
5884                 /* Prepare right boundary */
5885                 len = count;
5886                 if (len > e1_blk + e1_len - lblk1)
5887                         len = e1_blk + e1_len - lblk1;
5888                 if (len > e2_blk + e2_len - lblk2)
5889                         len = e2_blk + e2_len - lblk2;
5890
5891                 if (len != e1_len) {
5892                         split = 1;
5893                         *erp = ext4_force_split_extent_at(handle, inode1,
5894                                                 &path1, lblk1 + len, 0);
5895                         if (unlikely(*erp))
5896                                 goto finish;
5897                 }
5898                 if (len != e2_len) {
5899                         split = 1;
5900                         *erp = ext4_force_split_extent_at(handle, inode2,
5901                                                 &path2, lblk2 + len, 0);
5902                         if (*erp)
5903                                 goto finish;
5904                 }
5905                 /* ext4_split_extent_at() may result in leaf extent split,
5906                  * path must to be revalidated. */
5907                 if (split)
5908                         goto repeat;
5909
5910                 BUG_ON(e2_len != e1_len);
5911                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5912                 if (unlikely(*erp))
5913                         goto finish;
5914                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5915                 if (unlikely(*erp))
5916                         goto finish;
5917
5918                 /* Both extents are fully inside boundaries. Swap it now */
5919                 tmp_ex = *ex1;
5920                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5921                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5922                 ex1->ee_len = cpu_to_le16(e2_len);
5923                 ex2->ee_len = cpu_to_le16(e1_len);
5924                 if (unwritten)
5925                         ext4_ext_mark_unwritten(ex2);
5926                 if (ext4_ext_is_unwritten(&tmp_ex))
5927                         ext4_ext_mark_unwritten(ex1);
5928
5929                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5930                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5931                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5932                                       path2->p_depth);
5933                 if (unlikely(*erp))
5934                         goto finish;
5935                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5936                                       path1->p_depth);
5937                 /*
5938                  * Looks scarry ah..? second inode already points to new blocks,
5939                  * and it was successfully dirtied. But luckily error may happen
5940                  * only due to journal error, so full transaction will be
5941                  * aborted anyway.
5942                  */
5943                 if (unlikely(*erp))
5944                         goto finish;
5945                 lblk1 += len;
5946                 lblk2 += len;
5947                 replaced_count += len;
5948                 count -= len;
5949
5950         repeat:
5951                 ext4_ext_drop_refs(path1);
5952                 kfree(path1);
5953                 ext4_ext_drop_refs(path2);
5954                 kfree(path2);
5955                 path1 = path2 = NULL;
5956         }
5957         return replaced_count;
5958 }