fs/ext4/extents.c

   1 /*
   2  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3  * Written by Alex Tomas <alex@clusterfs.com>
   4  *
   5  * Architecture independence:
   6  *   Copyright (c) 2005, Bull S.A.
   7  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public Licens
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21  */
  22
  23 /*
  24  * Extents support for EXT4
  25  *
  26  * TODO:
  27  *   - ext4*_error() should be used in some situations
  28  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29  *   - smart tree reduction
  30  */
  31
  32 #include <linux/fs.h>
  33 #include <linux/time.h>
  34 #include <linux/jbd2.h>
  35 #include <linux/highuid.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/quotaops.h>
  38 #include <linux/string.h>
  39 #include <linux/slab.h>
  40 #include <linux/falloc.h>
  41 #include <asm/uaccess.h>
  42 #include <linux/fiemap.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_UNINIT1   0x2  /* mark first half uninitialized */
  55 #define EXT4_EXT_MARK_UNINIT2   0x4  /* mark second half uninitialized */
  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 *path,
 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 *path,
 108                              ext4_lblk_t split,
 109                              int split_flag,
 110                              int flags);
 111
 112 static int ext4_find_delayed_extent(struct inode *inode,
 113                                     struct extent_status *newes);
 114
 115 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 116                                             struct inode *inode,
 117                                             int needed)
 118 {
 119         int err;
 120
 121         if (!ext4_handle_valid(handle))
 122                 return 0;
 123         if (handle->h_buffer_credits > needed)
 124                 return 0;
 125         err = ext4_journal_extend(handle, needed);
 126         if (err <= 0)
 127                 return err;
 128         err = ext4_truncate_restart_trans(handle, inode, needed);
 129         if (err == 0)
 130                 err = -EAGAIN;
 131
 132         return err;
 133 }
 134
 135 /*
 136  * could return:
 137  *  - EROFS
 138  *  - ENOMEM
 139  */
 140 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 141                                 struct ext4_ext_path *path)
 142 {
 143         if (path->p_bh) {
 144                 /* path points to block */
 145                 return ext4_journal_get_write_access(handle, path->p_bh);
 146         }
 147         /* path points to leaf/index in inode body */
 148         /* we use in-core data, no need to protect them */
 149         return 0;
 150 }
 151
 152 /*
 153  * could return:
 154  *  - EROFS
 155  *  - ENOMEM
 156  *  - EIO
 157  */
 158 int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 159                      struct inode *inode, struct ext4_ext_path *path)
 160 {
 161         int err;
 162         if (path->p_bh) {
 163                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 164                 /* path points to block */
 165                 err = __ext4_handle_dirty_metadata(where, line, handle,
 166                                                    inode, path->p_bh);
 167         } else {
 168                 /* path points to leaf/index in inode body */
 169                 err = ext4_mark_inode_dirty(handle, inode);
 170         }
 171         return err;
 172 }
 173
 174 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 175                               struct ext4_ext_path *path,
 176                               ext4_lblk_t block)
 177 {
 178         if (path) {
 179                 int depth = path->p_depth;
 180                 struct ext4_extent *ex;
 181
 182                 /*
 183                  * Try to predict block placement assuming that we are
 184                  * filling in a file which will eventually be
 185                  * non-sparse --- i.e., in the case of libbfd writing
 186                  * an ELF object sections out-of-order but in a way
 187                  * the eventually results in a contiguous object or
 188                  * executable file, or some database extending a table
 189                  * space file.  However, this is actually somewhat
 190                  * non-ideal if we are writing a sparse file such as
 191                  * qemu or KVM writing a raw image file that is going
 192                  * to stay fairly sparse, since it will end up
 193                  * fragmenting the file system's free space.  Maybe we
 194                  * should have some hueristics or some way to allow
 195                  * userspace to pass a hint to file system,
 196                  * especially if the latter case turns out to be
 197                  * common.
 198                  */
 199                 ex = path[depth].p_ext;
 200                 if (ex) {
 201                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 202                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 203
 204                         if (block > ext_block)
 205                                 return ext_pblk + (block - ext_block);
 206                         else
 207                                 return ext_pblk - (ext_block - block);
 208                 }
 209
 210                 /* it looks like index is empty;
 211                  * try to find starting block from index itself */
 212                 if (path[depth].p_bh)
 213                         return path[depth].p_bh->b_blocknr;
 214         }
 215
 216         /* OK. use inode's group */
 217         return ext4_inode_to_goal_block(inode);
 218 }
 219
 220 /*
 221  * Allocation for a meta data block
 222  */
 223 static ext4_fsblk_t
 224 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 225                         struct ext4_ext_path *path,
 226                         struct ext4_extent *ex, int *err, unsigned int flags)
 227 {
 228         ext4_fsblk_t goal, newblock;
 229
 230         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 231         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 232                                         NULL, err);
 233         return newblock;
 234 }
 235
 236 static inline int ext4_ext_space_block(struct inode *inode, int check)
 237 {
 238         int size;
 239
 240         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 241                         / sizeof(struct ext4_extent);
 242 #ifdef AGGRESSIVE_TEST
 243         if (!check && size > 6)
 244                 size = 6;
 245 #endif
 246         return size;
 247 }
 248
 249 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 250 {
 251         int size;
 252
 253         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 254                         / sizeof(struct ext4_extent_idx);
 255 #ifdef AGGRESSIVE_TEST
 256         if (!check && size > 5)
 257                 size = 5;
 258 #endif
 259         return size;
 260 }
 261
 262 static inline int ext4_ext_space_root(struct inode *inode, int check)
 263 {
 264         int size;
 265
 266         size = sizeof(EXT4_I(inode)->i_data);
 267         size -= sizeof(struct ext4_extent_header);
 268         size /= sizeof(struct ext4_extent);
 269 #ifdef AGGRESSIVE_TEST
 270         if (!check && size > 3)
 271                 size = 3;
 272 #endif
 273         return size;
 274 }
 275
 276 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 277 {
 278         int size;
 279
 280         size = sizeof(EXT4_I(inode)->i_data);
 281         size -= sizeof(struct ext4_extent_header);
 282         size /= sizeof(struct ext4_extent_idx);
 283 #ifdef AGGRESSIVE_TEST
 284         if (!check && size > 4)
 285                 size = 4;
 286 #endif
 287         return size;
 288 }
 289
 290 /*
 291  * Calculate the number of metadata blocks needed
 292  * to allocate @blocks
 293  * Worse case is one block per extent
 294  */
 295 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 296 {
 297         struct ext4_inode_info *ei = EXT4_I(inode);
 298         int idxs;
 299
 300         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 301                 / sizeof(struct ext4_extent_idx));
 302
 303         /*
 304          * If the new delayed allocation block is contiguous with the
 305          * previous da block, it can share index blocks with the
 306          * previous block, so we only need to allocate a new index
 307          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 308          * an additional index block, and at ldxs**3 blocks, yet
 309          * another index blocks.
 310          */
 311         if (ei->i_da_metadata_calc_len &&
 312             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 313                 int num = 0;
 314
 315                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 316                         num++;
 317                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 318                         num++;
 319                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 320                         num++;
 321                         ei->i_da_metadata_calc_len = 0;
 322                 } else
 323                         ei->i_da_metadata_calc_len++;
 324                 ei->i_da_metadata_calc_last_lblock++;
 325                 return num;
 326         }
 327
 328         /*
 329          * In the worst case we need a new set of index blocks at
 330          * every level of the inode's extent tree.
 331          */
 332         ei->i_da_metadata_calc_len = 1;
 333         ei->i_da_metadata_calc_last_lblock = lblock;
 334         return ext_depth(inode) + 1;
 335 }
 336
 337 static int
 338 ext4_ext_max_entries(struct inode *inode, int depth)
 339 {
 340         int max;
 341
 342         if (depth == ext_depth(inode)) {
 343                 if (depth == 0)
 344                         max = ext4_ext_space_root(inode, 1);
 345                 else
 346                         max = ext4_ext_space_root_idx(inode, 1);
 347         } else {
 348                 if (depth == 0)
 349                         max = ext4_ext_space_block(inode, 1);
 350                 else
 351                         max = ext4_ext_space_block_idx(inode, 1);
 352         }
 353
 354         return max;
 355 }
 356
 357 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 358 {
 359         ext4_fsblk_t block = ext4_ext_pblock(ext);
 360         int len = ext4_ext_get_actual_len(ext);
 361         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 362         ext4_lblk_t last = lblock + len - 1;
 363
 364         if (lblock > last)
 365                 return 0;
 366         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 367 }
 368
 369 static int ext4_valid_extent_idx(struct inode *inode,
 370                                 struct ext4_extent_idx *ext_idx)
 371 {
 372         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 373
 374         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 375 }
 376
 377 static int ext4_valid_extent_entries(struct inode *inode,
 378                                 struct ext4_extent_header *eh,
 379                                 int depth)
 380 {
 381         unsigned short entries;
 382         if (eh->eh_entries == 0)
 383                 return 1;
 384
 385         entries = le16_to_cpu(eh->eh_entries);
 386
 387         if (depth == 0) {
 388                 /* leaf entries */
 389                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 390                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 391                 ext4_fsblk_t pblock = 0;
 392                 ext4_lblk_t lblock = 0;
 393                 ext4_lblk_t prev = 0;
 394                 int len = 0;
 395                 while (entries) {
 396                         if (!ext4_valid_extent(inode, ext))
 397                                 return 0;
 398
 399                         /* Check for overlapping extents */
 400                         lblock = le32_to_cpu(ext->ee_block);
 401                         len = ext4_ext_get_actual_len(ext);
 402                         if ((lblock <= prev) && prev) {
 403                                 pblock = ext4_ext_pblock(ext);
 404                                 es->s_last_error_block = cpu_to_le64(pblock);
 405                                 return 0;
 406                         }
 407                         ext++;
 408                         entries--;
 409                         prev = lblock + len - 1;
 410                 }
 411         } else {
 412                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 413                 while (entries) {
 414                         if (!ext4_valid_extent_idx(inode, ext_idx))
 415                                 return 0;
 416                         ext_idx++;
 417                         entries--;
 418                 }
 419         }
 420         return 1;
 421 }
 422
 423 static int __ext4_ext_check(const char *function, unsigned int line,
 424                             struct inode *inode, struct ext4_extent_header *eh,
 425                             int depth, ext4_fsblk_t pblk)
 426 {
 427         const char *error_msg;
 428         int max = 0;
 429
 430         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 431                 error_msg = "invalid magic";
 432                 goto corrupted;
 433         }
 434         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 435                 error_msg = "unexpected eh_depth";
 436                 goto corrupted;
 437         }
 438         if (unlikely(eh->eh_max == 0)) {
 439                 error_msg = "invalid eh_max";
 440                 goto corrupted;
 441         }
 442         max = ext4_ext_max_entries(inode, depth);
 443         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 444                 error_msg = "too large eh_max";
 445                 goto corrupted;
 446         }
 447         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 448                 error_msg = "invalid eh_entries";
 449                 goto corrupted;
 450         }
 451         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 452                 error_msg = "invalid extent entries";
 453                 goto corrupted;
 454         }
 455         /* Verify checksum on non-root extent tree nodes */
 456         if (ext_depth(inode) != depth &&
 457             !ext4_extent_block_csum_verify(inode, eh)) {
 458                 error_msg = "extent tree corrupted";
 459                 goto corrupted;
 460         }
 461         return 0;
 462
 463 corrupted:
 464         ext4_error_inode(inode, function, line, 0,
 465                          "pblk %llu bad header/extent: %s - magic %x, "
 466                          "entries %u, max %u(%u), depth %u(%u)",
 467                          (unsigned long long) pblk, error_msg,
 468                          le16_to_cpu(eh->eh_magic),
 469                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 470                          max, le16_to_cpu(eh->eh_depth), depth);
 471         return -EIO;
 472 }
 473
 474 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 475         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 476
 477 int ext4_ext_check_inode(struct inode *inode)
 478 {
 479         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 480 }
 481
 482 static struct buffer_head *
 483 __read_extent_tree_block(const char *function, unsigned int line,
 484                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 485                          int flags)
 486 {
 487         struct buffer_head              *bh;
 488         int                             err;
 489
 490         bh = sb_getblk(inode->i_sb, pblk);
 491         if (unlikely(!bh))
 492                 return ERR_PTR(-ENOMEM);
 493
 494         if (!bh_uptodate_or_lock(bh)) {
 495                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 496                 err = bh_submit_read(bh);
 497                 if (err < 0)
 498                         goto errout;
 499         }
 500         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 501                 return bh;
 502         err = __ext4_ext_check(function, line, inode,
 503                                ext_block_hdr(bh), depth, pblk);
 504         if (err)
 505                 goto errout;
 506         set_buffer_verified(bh);
 507         /*
 508          * If this is a leaf block, cache all of its entries
 509          */
 510         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 511                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 512                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 513                 ext4_lblk_t prev = 0;
 514                 int i;
 515
 516                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 517                         unsigned int status = EXTENT_STATUS_WRITTEN;
 518                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 519                         int len = ext4_ext_get_actual_len(ex);
 520
 521                         if (prev && (prev != lblk))
 522                                 ext4_es_cache_extent(inode, prev,
 523                                                      lblk - prev, ~0,
 524                                                      EXTENT_STATUS_HOLE);
 525
 526                         if (ext4_ext_is_uninitialized(ex))
 527                                 status = EXTENT_STATUS_UNWRITTEN;
 528                         ext4_es_cache_extent(inode, lblk, len,
 529                                              ext4_ext_pblock(ex), status);
 530                         prev = lblk + len;
 531                 }
 532         }
 533         return bh;
 534 errout:
 535         put_bh(bh);
 536         return ERR_PTR(err);
 537
 538 }
 539
 540 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 541         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 542                                  (depth), (flags))
 543
 544 /*
 545  * This function is called to cache a file's extent information in the
 546  * extent status tree
 547  */
 548 int ext4_ext_precache(struct inode *inode)
 549 {
 550         struct ext4_inode_info *ei = EXT4_I(inode);
 551         struct ext4_ext_path *path = NULL;
 552         struct buffer_head *bh;
 553         int i = 0, depth, ret = 0;
 554
 555         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 556                 return 0;       /* not an extent-mapped inode */
 557
 558         down_read(&ei->i_data_sem);
 559         depth = ext_depth(inode);
 560
 561         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 562                        GFP_NOFS);
 563         if (path == NULL) {
 564                 up_read(&ei->i_data_sem);
 565                 return -ENOMEM;
 566         }
 567
 568         /* Don't cache anything if there are no external extent blocks */
 569         if (depth == 0)
 570                 goto out;
 571         path[0].p_hdr = ext_inode_hdr(inode);
 572         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 573         if (ret)
 574                 goto out;
 575         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 576         while (i >= 0) {
 577                 /*
 578                  * If this is a leaf block or we've reached the end of
 579                  * the index block, go up
 580                  */
 581                 if ((i == depth) ||
 582                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 583                         brelse(path[i].p_bh);
 584                         path[i].p_bh = NULL;
 585                         i--;
 586                         continue;
 587                 }
 588                 bh = read_extent_tree_block(inode,
 589                                             ext4_idx_pblock(path[i].p_idx++),
 590                                             depth - i - 1,
 591                                             EXT4_EX_FORCE_CACHE);
 592                 if (IS_ERR(bh)) {
 593                         ret = PTR_ERR(bh);
 594                         break;
 595                 }
 596                 i++;
 597                 path[i].p_bh = bh;
 598                 path[i].p_hdr = ext_block_hdr(bh);
 599                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 600         }
 601         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 602 out:
 603         up_read(&ei->i_data_sem);
 604         ext4_ext_drop_refs(path);
 605         kfree(path);
 606         return ret;
 607 }
 608
 609 #ifdef EXT_DEBUG
 610 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 611 {
 612         int k, l = path->p_depth;
 613
 614         ext_debug("path:");
 615         for (k = 0; k <= l; k++, path++) {
 616                 if (path->p_idx) {
 617                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 618                             ext4_idx_pblock(path->p_idx));
 619                 } else if (path->p_ext) {
 620                         ext_debug("  %d:[%d]%d:%llu ",
 621                                   le32_to_cpu(path->p_ext->ee_block),
 622                                   ext4_ext_is_uninitialized(path->p_ext),
 623                                   ext4_ext_get_actual_len(path->p_ext),
 624                                   ext4_ext_pblock(path->p_ext));
 625                 } else
 626                         ext_debug("  []");
 627         }
 628         ext_debug("\n");
 629 }
 630
 631 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 632 {
 633         int depth = ext_depth(inode);
 634         struct ext4_extent_header *eh;
 635         struct ext4_extent *ex;
 636         int i;
 637
 638         if (!path)
 639                 return;
 640
 641         eh = path[depth].p_hdr;
 642         ex = EXT_FIRST_EXTENT(eh);
 643
 644         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 645
 646         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 647                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 648                           ext4_ext_is_uninitialized(ex),
 649                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 650         }
 651         ext_debug("\n");
 652 }
 653
 654 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 655                         ext4_fsblk_t newblock, int level)
 656 {
 657         int depth = ext_depth(inode);
 658         struct ext4_extent *ex;
 659
 660         if (depth != level) {
 661                 struct ext4_extent_idx *idx;
 662                 idx = path[level].p_idx;
 663                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 664                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 665                                         le32_to_cpu(idx->ei_block),
 666                                         ext4_idx_pblock(idx),
 667                                         newblock);
 668                         idx++;
 669                 }
 670
 671                 return;
 672         }
 673
 674         ex = path[depth].p_ext;
 675         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 676                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 677                                 le32_to_cpu(ex->ee_block),
 678                                 ext4_ext_pblock(ex),
 679                                 ext4_ext_is_uninitialized(ex),
 680                                 ext4_ext_get_actual_len(ex),
 681                                 newblock);
 682                 ex++;
 683         }
 684 }
 685
 686 #else
 687 #define ext4_ext_show_path(inode, path)
 688 #define ext4_ext_show_leaf(inode, path)
 689 #define ext4_ext_show_move(inode, path, newblock, level)
 690 #endif
 691
 692 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 693 {
 694         int depth = path->p_depth;
 695         int i;
 696
 697         for (i = 0; i <= depth; i++, path++)
 698                 if (path->p_bh) {
 699                         brelse(path->p_bh);
 700                         path->p_bh = NULL;
 701                 }
 702 }
 703
 704 /*
 705  * ext4_ext_binsearch_idx:
 706  * binary search for the closest index of the given block
 707  * the header must be checked before calling this
 708  */
 709 static void
 710 ext4_ext_binsearch_idx(struct inode *inode,
 711                         struct ext4_ext_path *path, ext4_lblk_t block)
 712 {
 713         struct ext4_extent_header *eh = path->p_hdr;
 714         struct ext4_extent_idx *r, *l, *m;
 715
 716
 717         ext_debug("binsearch for %u(idx):  ", block);
 718
 719         l = EXT_FIRST_INDEX(eh) + 1;
 720         r = EXT_LAST_INDEX(eh);
 721         while (l <= r) {
 722                 m = l + (r - l) / 2;
 723                 if (block < le32_to_cpu(m->ei_block))
 724                         r = m - 1;
 725                 else
 726                         l = m + 1;
 727                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 728                                 m, le32_to_cpu(m->ei_block),
 729                                 r, le32_to_cpu(r->ei_block));
 730         }
 731
 732         path->p_idx = l - 1;
 733         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 734                   ext4_idx_pblock(path->p_idx));
 735
 736 #ifdef CHECK_BINSEARCH
 737         {
 738                 struct ext4_extent_idx *chix, *ix;
 739                 int k;
 740
 741                 chix = ix = EXT_FIRST_INDEX(eh);
 742                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 743                   if (k != 0 &&
 744                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 745                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 746                                        "first=0x%p\n", k,
 747                                        ix, EXT_FIRST_INDEX(eh));
 748                                 printk(KERN_DEBUG "%u <= %u\n",
 749                                        le32_to_cpu(ix->ei_block),
 750                                        le32_to_cpu(ix[-1].ei_block));
 751                         }
 752                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 753                                            <= le32_to_cpu(ix[-1].ei_block));
 754                         if (block < le32_to_cpu(ix->ei_block))
 755                                 break;
 756                         chix = ix;
 757                 }
 758                 BUG_ON(chix != path->p_idx);
 759         }
 760 #endif
 761
 762 }
 763
 764 /*
 765  * ext4_ext_binsearch:
 766  * binary search for closest extent of the given block
 767  * the header must be checked before calling this
 768  */
 769 static void
 770 ext4_ext_binsearch(struct inode *inode,
 771                 struct ext4_ext_path *path, ext4_lblk_t block)
 772 {
 773         struct ext4_extent_header *eh = path->p_hdr;
 774         struct ext4_extent *r, *l, *m;
 775
 776         if (eh->eh_entries == 0) {
 777                 /*
 778                  * this leaf is empty:
 779                  * we get such a leaf in split/add case
 780                  */
 781                 return;
 782         }
 783
 784         ext_debug("binsearch for %u:  ", block);
 785
 786         l = EXT_FIRST_EXTENT(eh) + 1;
 787         r = EXT_LAST_EXTENT(eh);
 788
 789         while (l <= r) {
 790                 m = l + (r - l) / 2;
 791                 if (block < le32_to_cpu(m->ee_block))
 792                         r = m - 1;
 793                 else
 794                         l = m + 1;
 795                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 796                                 m, le32_to_cpu(m->ee_block),
 797                                 r, le32_to_cpu(r->ee_block));
 798         }
 799
 800         path->p_ext = l - 1;
 801         ext_debug("  -> %d:%llu:[%d]%d ",
 802                         le32_to_cpu(path->p_ext->ee_block),
 803                         ext4_ext_pblock(path->p_ext),
 804                         ext4_ext_is_uninitialized(path->p_ext),
 805                         ext4_ext_get_actual_len(path->p_ext));
 806
 807 #ifdef CHECK_BINSEARCH
 808         {
 809                 struct ext4_extent *chex, *ex;
 810                 int k;
 811
 812                 chex = ex = EXT_FIRST_EXTENT(eh);
 813                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 814                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 815                                           <= le32_to_cpu(ex[-1].ee_block));
 816                         if (block < le32_to_cpu(ex->ee_block))
 817                                 break;
 818                         chex = ex;
 819                 }
 820                 BUG_ON(chex != path->p_ext);
 821         }
 822 #endif
 823
 824 }
 825
 826 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 827 {
 828         struct ext4_extent_header *eh;
 829
 830         eh = ext_inode_hdr(inode);
 831         eh->eh_depth = 0;
 832         eh->eh_entries = 0;
 833         eh->eh_magic = EXT4_EXT_MAGIC;
 834         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 835         ext4_mark_inode_dirty(handle, inode);
 836         return 0;
 837 }
 838
 839 struct ext4_ext_path *
 840 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 841                      struct ext4_ext_path *path, int flags)
 842 {
 843         struct ext4_extent_header *eh;
 844         struct buffer_head *bh;
 845         short int depth, i, ppos = 0, alloc = 0;
 846         int ret;
 847
 848         eh = ext_inode_hdr(inode);
 849         depth = ext_depth(inode);
 850
 851         /* account possible depth increase */
 852         if (!path) {
 853                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 854                                 GFP_NOFS);
 855                 if (!path)
 856                         return ERR_PTR(-ENOMEM);
 857                 alloc = 1;
 858         }
 859         path[0].p_hdr = eh;
 860         path[0].p_bh = NULL;
 861
 862         i = depth;
 863         /* walk through the tree */
 864         while (i) {
 865                 ext_debug("depth %d: num %d, max %d\n",
 866                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 867
 868                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 869                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 870                 path[ppos].p_depth = i;
 871                 path[ppos].p_ext = NULL;
 872
 873                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 874                                             flags);
 875                 if (IS_ERR(bh)) {
 876                         ret = PTR_ERR(bh);
 877                         goto err;
 878                 }
 879
 880                 eh = ext_block_hdr(bh);
 881                 ppos++;
 882                 if (unlikely(ppos > depth)) {
 883                         put_bh(bh);
 884                         EXT4_ERROR_INODE(inode,
 885                                          "ppos %d > depth %d", ppos, depth);
 886                         ret = -EIO;
 887                         goto err;
 888                 }
 889                 path[ppos].p_bh = bh;
 890                 path[ppos].p_hdr = eh;
 891         }
 892
 893         path[ppos].p_depth = i;
 894         path[ppos].p_ext = NULL;
 895         path[ppos].p_idx = NULL;
 896
 897         /* find extent */
 898         ext4_ext_binsearch(inode, path + ppos, block);
 899         /* if not an empty leaf */
 900         if (path[ppos].p_ext)
 901                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 902
 903         ext4_ext_show_path(inode, path);
 904
 905         return path;
 906
 907 err:
 908         ext4_ext_drop_refs(path);
 909         if (alloc)
 910                 kfree(path);
 911         return ERR_PTR(ret);
 912 }
 913
 914 /*
 915  * ext4_ext_insert_index:
 916  * insert new index [@logical;@ptr] into the block at @curp;
 917  * check where to insert: before @curp or after @curp
 918  */
 919 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 920                                  struct ext4_ext_path *curp,
 921                                  int logical, ext4_fsblk_t ptr)
 922 {
 923         struct ext4_extent_idx *ix;
 924         int len, err;
 925
 926         err = ext4_ext_get_access(handle, inode, curp);
 927         if (err)
 928                 return err;
 929
 930         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 931                 EXT4_ERROR_INODE(inode,
 932                                  "logical %d == ei_block %d!",
 933                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 934                 return -EIO;
 935         }
 936
 937         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 938                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 939                 EXT4_ERROR_INODE(inode,
 940                                  "eh_entries %d >= eh_max %d!",
 941                                  le16_to_cpu(curp->p_hdr->eh_entries),
 942                                  le16_to_cpu(curp->p_hdr->eh_max));
 943                 return -EIO;
 944         }
 945
 946         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 947                 /* insert after */
 948                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 949                 ix = curp->p_idx + 1;
 950         } else {
 951                 /* insert before */
 952                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 953                 ix = curp->p_idx;
 954         }
 955
 956         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 957         BUG_ON(len < 0);
 958         if (len > 0) {
 959                 ext_debug("insert new index %d: "
 960                                 "move %d indices from 0x%p to 0x%p\n",
 961                                 logical, len, ix, ix + 1);
 962                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 963         }
 964
 965         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 966                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 967                 return -EIO;
 968         }
 969
 970         ix->ei_block = cpu_to_le32(logical);
 971         ext4_idx_store_pblock(ix, ptr);
 972         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 973
 974         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 975                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 976                 return -EIO;
 977         }
 978
 979         err = ext4_ext_dirty(handle, inode, curp);
 980         ext4_std_error(inode->i_sb, err);
 981
 982         return err;
 983 }
 984
 985 /*
 986  * ext4_ext_split:
 987  * inserts new subtree into the path, using free index entry
 988  * at depth @at:
 989  * - allocates all needed blocks (new leaf and all intermediate index blocks)
 990  * - makes decision where to split
 991  * - moves remaining extents and index entries (right to the split point)
 992  *   into the newly allocated blocks
 993  * - initializes subtree
 994  */
 995 static int ext4_ext_split(handle_t *handle, struct inode *inode,
 996                           unsigned int flags,
 997                           struct ext4_ext_path *path,
 998                           struct ext4_extent *newext, int at)
 999 {
1000         struct buffer_head *bh = NULL;
1001         int depth = ext_depth(inode);
1002         struct ext4_extent_header *neh;
1003         struct ext4_extent_idx *fidx;
1004         int i = at, k, m, a;
1005         ext4_fsblk_t newblock, oldblock;
1006         __le32 border;
1007         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1008         int err = 0;
1009
1010         /* make decision: where to split? */
1011         /* FIXME: now decision is simplest: at current extent */
1012
1013         /* if current leaf will be split, then we should use
1014          * border from split point */
1015         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1016                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1017                 return -EIO;
1018         }
1019         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1020                 border = path[depth].p_ext[1].ee_block;
1021                 ext_debug("leaf will be split."
1022                                 " next leaf starts at %d\n",
1023                                   le32_to_cpu(border));
1024         } else {
1025                 border = newext->ee_block;
1026                 ext_debug("leaf will be added."
1027                                 " next leaf starts at %d\n",
1028                                 le32_to_cpu(border));
1029         }
1030
1031         /*
1032          * If error occurs, then we break processing
1033          * and mark filesystem read-only. index won't
1034          * be inserted and tree will be in consistent
1035          * state. Next mount will repair buffers too.
1036          */
1037
1038         /*
1039          * Get array to track all allocated blocks.
1040          * We need this to handle errors and free blocks
1041          * upon them.
1042          */
1043         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1044         if (!ablocks)
1045                 return -ENOMEM;
1046
1047         /* allocate all needed blocks */
1048         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1049         for (a = 0; a < depth - at; a++) {
1050                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1051                                                    newext, &err, flags);
1052                 if (newblock == 0)
1053                         goto cleanup;
1054                 ablocks[a] = newblock;
1055         }
1056
1057         /* initialize new leaf */
1058         newblock = ablocks[--a];
1059         if (unlikely(newblock == 0)) {
1060                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1061                 err = -EIO;
1062                 goto cleanup;
1063         }
1064         bh = sb_getblk(inode->i_sb, newblock);
1065         if (unlikely(!bh)) {
1066                 err = -ENOMEM;
1067                 goto cleanup;
1068         }
1069         lock_buffer(bh);
1070
1071         err = ext4_journal_get_create_access(handle, bh);
1072         if (err)
1073                 goto cleanup;
1074
1075         neh = ext_block_hdr(bh);
1076         neh->eh_entries = 0;
1077         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1078         neh->eh_magic = EXT4_EXT_MAGIC;
1079         neh->eh_depth = 0;
1080
1081         /* move remainder of path[depth] to the new leaf */
1082         if (unlikely(path[depth].p_hdr->eh_entries !=
1083                      path[depth].p_hdr->eh_max)) {
1084                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1085                                  path[depth].p_hdr->eh_entries,
1086                                  path[depth].p_hdr->eh_max);
1087                 err = -EIO;
1088                 goto cleanup;
1089         }
1090         /* start copy from next extent */
1091         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1092         ext4_ext_show_move(inode, path, newblock, depth);
1093         if (m) {
1094                 struct ext4_extent *ex;
1095                 ex = EXT_FIRST_EXTENT(neh);
1096                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1097                 le16_add_cpu(&neh->eh_entries, m);
1098         }
1099
1100         ext4_extent_block_csum_set(inode, neh);
1101         set_buffer_uptodate(bh);
1102         unlock_buffer(bh);
1103
1104         err = ext4_handle_dirty_metadata(handle, inode, bh);
1105         if (err)
1106                 goto cleanup;
1107         brelse(bh);
1108         bh = NULL;
1109
1110         /* correct old leaf */
1111         if (m) {
1112                 err = ext4_ext_get_access(handle, inode, path + depth);
1113                 if (err)
1114                         goto cleanup;
1115                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1116                 err = ext4_ext_dirty(handle, inode, path + depth);
1117                 if (err)
1118                         goto cleanup;
1119
1120         }
1121
1122         /* create intermediate indexes */
1123         k = depth - at - 1;
1124         if (unlikely(k < 0)) {
1125                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1126                 err = -EIO;
1127                 goto cleanup;
1128         }
1129         if (k)
1130                 ext_debug("create %d intermediate indices\n", k);
1131         /* insert new index into current index block */
1132         /* current depth stored in i var */
1133         i = depth - 1;
1134         while (k--) {
1135                 oldblock = newblock;
1136                 newblock = ablocks[--a];
1137                 bh = sb_getblk(inode->i_sb, newblock);
1138                 if (unlikely(!bh)) {
1139                         err = -ENOMEM;
1140                         goto cleanup;
1141                 }
1142                 lock_buffer(bh);
1143
1144                 err = ext4_journal_get_create_access(handle, bh);
1145                 if (err)
1146                         goto cleanup;
1147
1148                 neh = ext_block_hdr(bh);
1149                 neh->eh_entries = cpu_to_le16(1);
1150                 neh->eh_magic = EXT4_EXT_MAGIC;
1151                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1152                 neh->eh_depth = cpu_to_le16(depth - i);
1153                 fidx = EXT_FIRST_INDEX(neh);
1154                 fidx->ei_block = border;
1155                 ext4_idx_store_pblock(fidx, oldblock);
1156
1157                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1158                                 i, newblock, le32_to_cpu(border), oldblock);
1159
1160                 /* move remainder of path[i] to the new index block */
1161                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1162                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1163                         EXT4_ERROR_INODE(inode,
1164                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1165                                          le32_to_cpu(path[i].p_ext->ee_block));
1166                         err = -EIO;
1167                         goto cleanup;
1168                 }
1169                 /* start copy indexes */
1170                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1171                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1172                                 EXT_MAX_INDEX(path[i].p_hdr));
1173                 ext4_ext_show_move(inode, path, newblock, i);
1174                 if (m) {
1175                         memmove(++fidx, path[i].p_idx,
1176                                 sizeof(struct ext4_extent_idx) * m);
1177                         le16_add_cpu(&neh->eh_entries, m);
1178                 }
1179                 ext4_extent_block_csum_set(inode, neh);
1180                 set_buffer_uptodate(bh);
1181                 unlock_buffer(bh);
1182
1183                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1184                 if (err)
1185                         goto cleanup;
1186                 brelse(bh);
1187                 bh = NULL;
1188
1189                 /* correct old index */
1190                 if (m) {
1191                         err = ext4_ext_get_access(handle, inode, path + i);
1192                         if (err)
1193                                 goto cleanup;
1194                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1195                         err = ext4_ext_dirty(handle, inode, path + i);
1196                         if (err)
1197                                 goto cleanup;
1198                 }
1199
1200                 i--;
1201         }
1202
1203         /* insert new index */
1204         err = ext4_ext_insert_index(handle, inode, path + at,
1205                                     le32_to_cpu(border), newblock);
1206
1207 cleanup:
1208         if (bh) {
1209                 if (buffer_locked(bh))
1210                         unlock_buffer(bh);
1211                 brelse(bh);
1212         }
1213
1214         if (err) {
1215                 /* free all allocated blocks in error case */
1216                 for (i = 0; i < depth; i++) {
1217                         if (!ablocks[i])
1218                                 continue;
1219                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1220                                          EXT4_FREE_BLOCKS_METADATA);
1221                 }
1222         }
1223         kfree(ablocks);
1224
1225         return err;
1226 }
1227
1228 /*
1229  * ext4_ext_grow_indepth:
1230  * implements tree growing procedure:
1231  * - allocates new block
1232  * - moves top-level data (index block or leaf) into the new block
1233  * - initializes new top-level, creating index that points to the
1234  *   just created block
1235  */
1236 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1237                                  unsigned int flags,
1238                                  struct ext4_extent *newext)
1239 {
1240         struct ext4_extent_header *neh;
1241         struct buffer_head *bh;
1242         ext4_fsblk_t newblock;
1243         int err = 0;
1244
1245         newblock = ext4_ext_new_meta_block(handle, inode, NULL,
1246                 newext, &err, flags);
1247         if (newblock == 0)
1248                 return err;
1249
1250         bh = sb_getblk(inode->i_sb, newblock);
1251         if (unlikely(!bh))
1252                 return -ENOMEM;
1253         lock_buffer(bh);
1254
1255         err = ext4_journal_get_create_access(handle, bh);
1256         if (err) {
1257                 unlock_buffer(bh);
1258                 goto out;
1259         }
1260
1261         /* move top-level index/leaf into new block */
1262         memmove(bh->b_data, EXT4_I(inode)->i_data,
1263                 sizeof(EXT4_I(inode)->i_data));
1264
1265         /* set size of new block */
1266         neh = ext_block_hdr(bh);
1267         /* old root could have indexes or leaves
1268          * so calculate e_max right way */
1269         if (ext_depth(inode))
1270                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1271         else
1272                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1273         neh->eh_magic = EXT4_EXT_MAGIC;
1274         ext4_extent_block_csum_set(inode, neh);
1275         set_buffer_uptodate(bh);
1276         unlock_buffer(bh);
1277
1278         err = ext4_handle_dirty_metadata(handle, inode, bh);
1279         if (err)
1280                 goto out;
1281
1282         /* Update top-level index: num,max,pointer */
1283         neh = ext_inode_hdr(inode);
1284         neh->eh_entries = cpu_to_le16(1);
1285         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1286         if (neh->eh_depth == 0) {
1287                 /* Root extent block becomes index block */
1288                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1289                 EXT_FIRST_INDEX(neh)->ei_block =
1290                         EXT_FIRST_EXTENT(neh)->ee_block;
1291         }
1292         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1293                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1294                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1295                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1296
1297         le16_add_cpu(&neh->eh_depth, 1);
1298         ext4_mark_inode_dirty(handle, inode);
1299 out:
1300         brelse(bh);
1301
1302         return err;
1303 }
1304
1305 /*
1306  * ext4_ext_create_new_leaf:
1307  * finds empty index and adds new leaf.
1308  * if no free index is found, then it requests in-depth growing.
1309  */
1310 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1311                                     unsigned int mb_flags,
1312                                     unsigned int gb_flags,
1313                                     struct ext4_ext_path *path,
1314                                     struct ext4_extent *newext)
1315 {
1316         struct ext4_ext_path *curp;
1317         int depth, i, err = 0;
1318
1319 repeat:
1320         i = depth = ext_depth(inode);
1321
1322         /* walk up to the tree and look for free index entry */
1323         curp = path + depth;
1324         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1325                 i--;
1326                 curp--;
1327         }
1328
1329         /* we use already allocated block for index block,
1330          * so subsequent data blocks should be contiguous */
1331         if (EXT_HAS_FREE_INDEX(curp)) {
1332                 /* if we found index with free entry, then use that
1333                  * entry: create all needed subtree and add new leaf */
1334                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1335                 if (err)
1336                         goto out;
1337
1338                 /* refill path */
1339                 ext4_ext_drop_refs(path);
1340                 path = ext4_ext_find_extent(inode,
1341                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1342                                     path, gb_flags);
1343                 if (IS_ERR(path))
1344                         err = PTR_ERR(path);
1345         } else {
1346                 /* tree is full, time to grow in depth */
1347                 err = ext4_ext_grow_indepth(handle, inode, mb_flags, newext);
1348                 if (err)
1349                         goto out;
1350
1351                 /* refill path */
1352                 ext4_ext_drop_refs(path);
1353                 path = ext4_ext_find_extent(inode,
1354                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1355                                     path, gb_flags);
1356                 if (IS_ERR(path)) {
1357                         err = PTR_ERR(path);
1358                         goto out;
1359                 }
1360
1361                 /*
1362                  * only first (depth 0 -> 1) produces free space;
1363                  * in all other cases we have to split the grown tree
1364                  */
1365                 depth = ext_depth(inode);
1366                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1367                         /* now we need to split */
1368                         goto repeat;
1369                 }
1370         }
1371
1372 out:
1373         return err;
1374 }
1375
1376 /*
1377  * search the closest allocated block to the left for *logical
1378  * and returns it at @logical + it's physical address at @phys
1379  * if *logical is the smallest allocated block, the function
1380  * returns 0 at @phys
1381  * return value contains 0 (success) or error code
1382  */
1383 static int ext4_ext_search_left(struct inode *inode,
1384                                 struct ext4_ext_path *path,
1385                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1386 {
1387         struct ext4_extent_idx *ix;
1388         struct ext4_extent *ex;
1389         int depth, ee_len;
1390
1391         if (unlikely(path == NULL)) {
1392                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1393                 return -EIO;
1394         }
1395         depth = path->p_depth;
1396         *phys = 0;
1397
1398         if (depth == 0 && path->p_ext == NULL)
1399                 return 0;
1400
1401         /* usually extent in the path covers blocks smaller
1402          * then *logical, but it can be that extent is the
1403          * first one in the file */
1404
1405         ex = path[depth].p_ext;
1406         ee_len = ext4_ext_get_actual_len(ex);
1407         if (*logical < le32_to_cpu(ex->ee_block)) {
1408                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1409                         EXT4_ERROR_INODE(inode,
1410                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1411                                          *logical, le32_to_cpu(ex->ee_block));
1412                         return -EIO;
1413                 }
1414                 while (--depth >= 0) {
1415                         ix = path[depth].p_idx;
1416                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1417                                 EXT4_ERROR_INODE(inode,
1418                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1419                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1420                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1421                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1422                                   depth);
1423                                 return -EIO;
1424                         }
1425                 }
1426                 return 0;
1427         }
1428
1429         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1430                 EXT4_ERROR_INODE(inode,
1431                                  "logical %d < ee_block %d + ee_len %d!",
1432                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1433                 return -EIO;
1434         }
1435
1436         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1437         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1438         return 0;
1439 }
1440
1441 /*
1442  * search the closest allocated block to the right for *logical
1443  * and returns it at @logical + it's physical address at @phys
1444  * if *logical is the largest allocated block, the function
1445  * returns 0 at @phys
1446  * return value contains 0 (success) or error code
1447  */
1448 static int ext4_ext_search_right(struct inode *inode,
1449                                  struct ext4_ext_path *path,
1450                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1451                                  struct ext4_extent **ret_ex)
1452 {
1453         struct buffer_head *bh = NULL;
1454         struct ext4_extent_header *eh;
1455         struct ext4_extent_idx *ix;
1456         struct ext4_extent *ex;
1457         ext4_fsblk_t block;
1458         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1459         int ee_len;
1460
1461         if (unlikely(path == NULL)) {
1462                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1463                 return -EIO;
1464         }
1465         depth = path->p_depth;
1466         *phys = 0;
1467
1468         if (depth == 0 && path->p_ext == NULL)
1469                 return 0;
1470
1471         /* usually extent in the path covers blocks smaller
1472          * then *logical, but it can be that extent is the
1473          * first one in the file */
1474
1475         ex = path[depth].p_ext;
1476         ee_len = ext4_ext_get_actual_len(ex);
1477         if (*logical < le32_to_cpu(ex->ee_block)) {
1478                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1479                         EXT4_ERROR_INODE(inode,
1480                                          "first_extent(path[%d].p_hdr) != ex",
1481                                          depth);
1482                         return -EIO;
1483                 }
1484                 while (--depth >= 0) {
1485                         ix = path[depth].p_idx;
1486                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1487                                 EXT4_ERROR_INODE(inode,
1488                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1489                                                  *logical);
1490                                 return -EIO;
1491                         }
1492                 }
1493                 goto found_extent;
1494         }
1495
1496         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1497                 EXT4_ERROR_INODE(inode,
1498                                  "logical %d < ee_block %d + ee_len %d!",
1499                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1500                 return -EIO;
1501         }
1502
1503         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1504                 /* next allocated block in this leaf */
1505                 ex++;
1506                 goto found_extent;
1507         }
1508
1509         /* go up and search for index to the right */
1510         while (--depth >= 0) {
1511                 ix = path[depth].p_idx;
1512                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1513                         goto got_index;
1514         }
1515
1516         /* we've gone up to the root and found no index to the right */
1517         return 0;
1518
1519 got_index:
1520         /* we've found index to the right, let's
1521          * follow it and find the closest allocated
1522          * block to the right */
1523         ix++;
1524         block = ext4_idx_pblock(ix);
1525         while (++depth < path->p_depth) {
1526                 /* subtract from p_depth to get proper eh_depth */
1527                 bh = read_extent_tree_block(inode, block,
1528                                             path->p_depth - depth, 0);
1529                 if (IS_ERR(bh))
1530                         return PTR_ERR(bh);
1531                 eh = ext_block_hdr(bh);
1532                 ix = EXT_FIRST_INDEX(eh);
1533                 block = ext4_idx_pblock(ix);
1534                 put_bh(bh);
1535         }
1536
1537         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1538         if (IS_ERR(bh))
1539                 return PTR_ERR(bh);
1540         eh = ext_block_hdr(bh);
1541         ex = EXT_FIRST_EXTENT(eh);
1542 found_extent:
1543         *logical = le32_to_cpu(ex->ee_block);
1544         *phys = ext4_ext_pblock(ex);
1545         *ret_ex = ex;
1546         if (bh)
1547                 put_bh(bh);
1548         return 0;
1549 }
1550
1551 /*
1552  * ext4_ext_next_allocated_block:
1553  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1554  * NOTE: it considers block number from index entry as
1555  * allocated block. Thus, index entries have to be consistent
1556  * with leaves.
1557  */
1558 static ext4_lblk_t
1559 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1560 {
1561         int depth;
1562
1563         BUG_ON(path == NULL);
1564         depth = path->p_depth;
1565
1566         if (depth == 0 && path->p_ext == NULL)
1567                 return EXT_MAX_BLOCKS;
1568
1569         while (depth >= 0) {
1570                 if (depth == path->p_depth) {
1571                         /* leaf */
1572                         if (path[depth].p_ext &&
1573                                 path[depth].p_ext !=
1574                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1575                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1576                 } else {
1577                         /* index */
1578                         if (path[depth].p_idx !=
1579                                         EXT_LAST_INDEX(path[depth].p_hdr))
1580                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1581                 }
1582                 depth--;
1583         }
1584
1585         return EXT_MAX_BLOCKS;
1586 }
1587
1588 /*
1589  * ext4_ext_next_leaf_block:
1590  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1591  */
1592 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1593 {
1594         int depth;
1595
1596         BUG_ON(path == NULL);
1597         depth = path->p_depth;
1598
1599         /* zero-tree has no leaf blocks at all */
1600         if (depth == 0)
1601                 return EXT_MAX_BLOCKS;
1602
1603         /* go to index block */
1604         depth--;
1605
1606         while (depth >= 0) {
1607                 if (path[depth].p_idx !=
1608                                 EXT_LAST_INDEX(path[depth].p_hdr))
1609                         return (ext4_lblk_t)
1610                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1611                 depth--;
1612         }
1613
1614         return EXT_MAX_BLOCKS;
1615 }
1616
1617 /*
1618  * ext4_ext_correct_indexes:
1619  * if leaf gets modified and modified extent is first in the leaf,
1620  * then we have to correct all indexes above.
1621  * TODO: do we need to correct tree in all cases?
1622  */
1623 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1624                                 struct ext4_ext_path *path)
1625 {
1626         struct ext4_extent_header *eh;
1627         int depth = ext_depth(inode);
1628         struct ext4_extent *ex;
1629         __le32 border;
1630         int k, err = 0;
1631
1632         eh = path[depth].p_hdr;
1633         ex = path[depth].p_ext;
1634
1635         if (unlikely(ex == NULL || eh == NULL)) {
1636                 EXT4_ERROR_INODE(inode,
1637                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1638                 return -EIO;
1639         }
1640
1641         if (depth == 0) {
1642                 /* there is no tree at all */
1643                 return 0;
1644         }
1645
1646         if (ex != EXT_FIRST_EXTENT(eh)) {
1647                 /* we correct tree if first leaf got modified only */
1648                 return 0;
1649         }
1650
1651         /*
1652          * TODO: we need correction if border is smaller than current one
1653          */
1654         k = depth - 1;
1655         border = path[depth].p_ext->ee_block;
1656         err = ext4_ext_get_access(handle, inode, path + k);
1657         if (err)
1658                 return err;
1659         path[k].p_idx->ei_block = border;
1660         err = ext4_ext_dirty(handle, inode, path + k);
1661         if (err)
1662                 return err;
1663
1664         while (k--) {
1665                 /* change all left-side indexes */
1666                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1667                         break;
1668                 err = ext4_ext_get_access(handle, inode, path + k);
1669                 if (err)
1670                         break;
1671                 path[k].p_idx->ei_block = border;
1672                 err = ext4_ext_dirty(handle, inode, path + k);
1673                 if (err)
1674                         break;
1675         }
1676
1677         return err;
1678 }
1679
1680 int
1681 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1682                                 struct ext4_extent *ex2)
1683 {
1684         unsigned short ext1_ee_len, ext2_ee_len;
1685
1686         /*
1687          * Make sure that both extents are initialized. We don't merge
1688          * uninitialized extents so that we can be sure that end_io code has
1689          * the extent that was written properly split out and conversion to
1690          * initialized is trivial.
1691          */
1692         if (ext4_ext_is_uninitialized(ex1) || ext4_ext_is_uninitialized(ex2))
1693                 return 0;
1694
1695         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1696         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1697
1698         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1699                         le32_to_cpu(ex2->ee_block))
1700                 return 0;
1701
1702         /*
1703          * To allow future support for preallocated extents to be added
1704          * as an RO_COMPAT feature, refuse to merge to extents if
1705          * this can result in the top bit of ee_len being set.
1706          */
1707         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1708                 return 0;
1709 #ifdef AGGRESSIVE_TEST
1710         if (ext1_ee_len >= 4)
1711                 return 0;
1712 #endif
1713
1714         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1715                 return 1;
1716         return 0;
1717 }
1718
1719 /*
1720  * This function tries to merge the "ex" extent to the next extent in the tree.
1721  * It always tries to merge towards right. If you want to merge towards
1722  * left, pass "ex - 1" as argument instead of "ex".
1723  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1724  * 1 if they got merged.
1725  */
1726 static int ext4_ext_try_to_merge_right(struct inode *inode,
1727                                  struct ext4_ext_path *path,
1728                                  struct ext4_extent *ex)
1729 {
1730         struct ext4_extent_header *eh;
1731         unsigned int depth, len;
1732         int merge_done = 0;
1733
1734         depth = ext_depth(inode);
1735         BUG_ON(path[depth].p_hdr == NULL);
1736         eh = path[depth].p_hdr;
1737
1738         while (ex < EXT_LAST_EXTENT(eh)) {
1739                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1740                         break;
1741                 /* merge with next extent! */
1742                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1743                                 + ext4_ext_get_actual_len(ex + 1));
1744
1745                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1746                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1747                                 * sizeof(struct ext4_extent);
1748                         memmove(ex + 1, ex + 2, len);
1749                 }
1750                 le16_add_cpu(&eh->eh_entries, -1);
1751                 merge_done = 1;
1752                 WARN_ON(eh->eh_entries == 0);
1753                 if (!eh->eh_entries)
1754                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1755         }
1756
1757         return merge_done;
1758 }
1759
1760 /*
1761  * This function does a very simple check to see if we can collapse
1762  * an extent tree with a single extent tree leaf block into the inode.
1763  */
1764 static void ext4_ext_try_to_merge_up(handle_t *handle,
1765                                      struct inode *inode,
1766                                      struct ext4_ext_path *path)
1767 {
1768         size_t s;
1769         unsigned max_root = ext4_ext_space_root(inode, 0);
1770         ext4_fsblk_t blk;
1771
1772         if ((path[0].p_depth != 1) ||
1773             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1774             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1775                 return;
1776
1777         /*
1778          * We need to modify the block allocation bitmap and the block
1779          * group descriptor to release the extent tree block.  If we
1780          * can't get the journal credits, give up.
1781          */
1782         if (ext4_journal_extend(handle, 2))
1783                 return;
1784
1785         /*
1786          * Copy the extent data up to the inode
1787          */
1788         blk = ext4_idx_pblock(path[0].p_idx);
1789         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1790                 sizeof(struct ext4_extent_idx);
1791         s += sizeof(struct ext4_extent_header);
1792
1793         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1794         path[0].p_depth = 0;
1795         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1796                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1797         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1798
1799         brelse(path[1].p_bh);
1800         ext4_free_blocks(handle, inode, NULL, blk, 1,
1801                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET |
1802                          EXT4_FREE_BLOCKS_RESERVE);
1803 }
1804
1805 /*
1806  * This function tries to merge the @ex extent to neighbours in the tree.
1807  * return 1 if merge left else 0.
1808  */
1809 static void ext4_ext_try_to_merge(handle_t *handle,
1810                                   struct inode *inode,
1811                                   struct ext4_ext_path *path,
1812                                   struct ext4_extent *ex) {
1813         struct ext4_extent_header *eh;
1814         unsigned int depth;
1815         int merge_done = 0;
1816
1817         depth = ext_depth(inode);
1818         BUG_ON(path[depth].p_hdr == NULL);
1819         eh = path[depth].p_hdr;
1820
1821         if (ex > EXT_FIRST_EXTENT(eh))
1822                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1823
1824         if (!merge_done)
1825                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1826
1827         ext4_ext_try_to_merge_up(handle, inode, path);
1828 }
1829
1830 /*
1831  * check if a portion of the "newext" extent overlaps with an
1832  * existing extent.
1833  *
1834  * If there is an overlap discovered, it updates the length of the newext
1835  * such that there will be no overlap, and then returns 1.
1836  * If there is no overlap found, it returns 0.
1837  */
1838 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1839                                            struct inode *inode,
1840                                            struct ext4_extent *newext,
1841                                            struct ext4_ext_path *path)
1842 {
1843         ext4_lblk_t b1, b2;
1844         unsigned int depth, len1;
1845         unsigned int ret = 0;
1846
1847         b1 = le32_to_cpu(newext->ee_block);
1848         len1 = ext4_ext_get_actual_len(newext);
1849         depth = ext_depth(inode);
1850         if (!path[depth].p_ext)
1851                 goto out;
1852         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1853
1854         /*
1855          * get the next allocated block if the extent in the path
1856          * is before the requested block(s)
1857          */
1858         if (b2 < b1) {
1859                 b2 = ext4_ext_next_allocated_block(path);
1860                 if (b2 == EXT_MAX_BLOCKS)
1861                         goto out;
1862                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1863         }
1864
1865         /* check for wrap through zero on extent logical start block*/
1866         if (b1 + len1 < b1) {
1867                 len1 = EXT_MAX_BLOCKS - b1;
1868                 newext->ee_len = cpu_to_le16(len1);
1869                 ret = 1;
1870         }
1871
1872         /* check for overlap */
1873         if (b1 + len1 > b2) {
1874                 newext->ee_len = cpu_to_le16(b2 - b1);
1875                 ret = 1;
1876         }
1877 out:
1878         return ret;
1879 }
1880
1881 /*
1882  * ext4_ext_insert_extent:
1883  * tries to merge requsted extent into the existing extent or
1884  * inserts requested extent as new one into the tree,
1885  * creating new leaf in the no-space case.
1886  */
1887 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1888                                 struct ext4_ext_path *path,
1889                                 struct ext4_extent *newext, int gb_flags)
1890 {
1891         struct ext4_extent_header *eh;
1892         struct ext4_extent *ex, *fex;
1893         struct ext4_extent *nearex; /* nearest extent */
1894         struct ext4_ext_path *npath = NULL;
1895         int depth, len, err;
1896         ext4_lblk_t next;
1897         int mb_flags = 0;
1898
1899         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1900                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1901                 return -EIO;
1902         }
1903         depth = ext_depth(inode);
1904         ex = path[depth].p_ext;
1905         eh = path[depth].p_hdr;
1906         if (unlikely(path[depth].p_hdr == NULL)) {
1907                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1908                 return -EIO;
1909         }
1910
1911         /* try to insert block into found extent and return */
1912         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1913
1914                 /*
1915                  * Try to see whether we should rather test the extent on
1916                  * right from ex, or from the left of ex. This is because
1917                  * ext4_ext_find_extent() can return either extent on the
1918                  * left, or on the right from the searched position. This
1919                  * will make merging more effective.
1920                  */
1921                 if (ex < EXT_LAST_EXTENT(eh) &&
1922                     (le32_to_cpu(ex->ee_block) +
1923                     ext4_ext_get_actual_len(ex) <
1924                     le32_to_cpu(newext->ee_block))) {
1925                         ex += 1;
1926                         goto prepend;
1927                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1928                            (le32_to_cpu(newext->ee_block) +
1929                            ext4_ext_get_actual_len(newext) <
1930                            le32_to_cpu(ex->ee_block)))
1931                         ex -= 1;
1932
1933                 /* Try to append newex to the ex */
1934                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1935                         ext_debug("append [%d]%d block to %u:[%d]%d"
1936                                   "(from %llu)\n",
1937                                   ext4_ext_is_uninitialized(newext),
1938                                   ext4_ext_get_actual_len(newext),
1939                                   le32_to_cpu(ex->ee_block),
1940                                   ext4_ext_is_uninitialized(ex),
1941                                   ext4_ext_get_actual_len(ex),
1942                                   ext4_ext_pblock(ex));
1943                         err = ext4_ext_get_access(handle, inode,
1944                                                   path + depth);
1945                         if (err)
1946                                 return err;
1947
1948                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1949                                         + ext4_ext_get_actual_len(newext));
1950                         eh = path[depth].p_hdr;
1951                         nearex = ex;
1952                         goto merge;
1953                 }
1954
1955 prepend:
1956                 /* Try to prepend newex to the ex */
1957                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
1958                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
1959                                   "(from %llu)\n",
1960                                   le32_to_cpu(newext->ee_block),
1961                                   ext4_ext_is_uninitialized(newext),
1962                                   ext4_ext_get_actual_len(newext),
1963                                   le32_to_cpu(ex->ee_block),
1964                                   ext4_ext_is_uninitialized(ex),
1965                                   ext4_ext_get_actual_len(ex),
1966                                   ext4_ext_pblock(ex));
1967                         err = ext4_ext_get_access(handle, inode,
1968                                                   path + depth);
1969                         if (err)
1970                                 return err;
1971
1972                         ex->ee_block = newext->ee_block;
1973                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
1974                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1975                                         + ext4_ext_get_actual_len(newext));
1976                         eh = path[depth].p_hdr;
1977                         nearex = ex;
1978                         goto merge;
1979                 }
1980         }
1981
1982         depth = ext_depth(inode);
1983         eh = path[depth].p_hdr;
1984         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1985                 goto has_space;
1986
1987         /* probably next leaf has space for us? */
1988         fex = EXT_LAST_EXTENT(eh);
1989         next = EXT_MAX_BLOCKS;
1990         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
1991                 next = ext4_ext_next_leaf_block(path);
1992         if (next != EXT_MAX_BLOCKS) {
1993                 ext_debug("next leaf block - %u\n", next);
1994                 BUG_ON(npath != NULL);
1995                 npath = ext4_ext_find_extent(inode, next, NULL, 0);
1996                 if (IS_ERR(npath))
1997                         return PTR_ERR(npath);
1998                 BUG_ON(npath->p_depth != path->p_depth);
1999                 eh = npath[depth].p_hdr;
2000                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2001                         ext_debug("next leaf isn't full(%d)\n",
2002                                   le16_to_cpu(eh->eh_entries));
2003                         path = npath;
2004                         goto has_space;
2005                 }
2006                 ext_debug("next leaf has no free space(%d,%d)\n",
2007                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2008         }
2009
2010         /*
2011          * There is no free space in the found leaf.
2012          * We're gonna add a new leaf in the tree.
2013          */
2014         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2015                 mb_flags = EXT4_MB_USE_RESERVED;
2016         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2017                                        path, newext);
2018         if (err)
2019                 goto cleanup;
2020         depth = ext_depth(inode);
2021         eh = path[depth].p_hdr;
2022
2023 has_space:
2024         nearex = path[depth].p_ext;
2025
2026         err = ext4_ext_get_access(handle, inode, path + depth);
2027         if (err)
2028                 goto cleanup;
2029
2030         if (!nearex) {
2031                 /* there is no extent in this leaf, create first one */
2032                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2033                                 le32_to_cpu(newext->ee_block),
2034                                 ext4_ext_pblock(newext),
2035                                 ext4_ext_is_uninitialized(newext),
2036                                 ext4_ext_get_actual_len(newext));
2037                 nearex = EXT_FIRST_EXTENT(eh);
2038         } else {
2039                 if (le32_to_cpu(newext->ee_block)
2040                            > le32_to_cpu(nearex->ee_block)) {
2041                         /* Insert after */
2042                         ext_debug("insert %u:%llu:[%d]%d before: "
2043                                         "nearest %p\n",
2044                                         le32_to_cpu(newext->ee_block),
2045                                         ext4_ext_pblock(newext),
2046                                         ext4_ext_is_uninitialized(newext),
2047                                         ext4_ext_get_actual_len(newext),
2048                                         nearex);
2049                         nearex++;
2050                 } else {
2051                         /* Insert before */
2052                         BUG_ON(newext->ee_block == nearex->ee_block);
2053                         ext_debug("insert %u:%llu:[%d]%d after: "
2054                                         "nearest %p\n",
2055                                         le32_to_cpu(newext->ee_block),
2056                                         ext4_ext_pblock(newext),
2057                                         ext4_ext_is_uninitialized(newext),
2058                                         ext4_ext_get_actual_len(newext),
2059                                         nearex);
2060                 }
2061                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2062                 if (len > 0) {
2063                         ext_debug("insert %u:%llu:[%d]%d: "
2064                                         "move %d extents from 0x%p to 0x%p\n",
2065                                         le32_to_cpu(newext->ee_block),
2066                                         ext4_ext_pblock(newext),
2067                                         ext4_ext_is_uninitialized(newext),
2068                                         ext4_ext_get_actual_len(newext),
2069                                         len, nearex, nearex + 1);
2070                         memmove(nearex + 1, nearex,
2071                                 len * sizeof(struct ext4_extent));
2072                 }
2073         }
2074
2075         le16_add_cpu(&eh->eh_entries, 1);
2076         path[depth].p_ext = nearex;
2077         nearex->ee_block = newext->ee_block;
2078         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2079         nearex->ee_len = newext->ee_len;
2080
2081 merge:
2082         /* try to merge extents */
2083         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2084                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2085
2086
2087         /* time to correct all indexes above */
2088         err = ext4_ext_correct_indexes(handle, inode, path);
2089         if (err)
2090                 goto cleanup;
2091
2092         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2093
2094 cleanup:
2095         if (npath) {
2096                 ext4_ext_drop_refs(npath);
2097                 kfree(npath);
2098         }
2099         return err;
2100 }
2101
2102 static int ext4_fill_fiemap_extents(struct inode *inode,
2103                                     ext4_lblk_t block, ext4_lblk_t num,
2104                                     struct fiemap_extent_info *fieinfo)
2105 {
2106         struct ext4_ext_path *path = NULL;
2107         struct ext4_extent *ex;
2108         struct extent_status es;
2109         ext4_lblk_t next, next_del, start = 0, end = 0;
2110         ext4_lblk_t last = block + num;
2111         int exists, depth = 0, err = 0;
2112         unsigned int flags = 0;
2113         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2114
2115         while (block < last && block != EXT_MAX_BLOCKS) {
2116                 num = last - block;
2117                 /* find extent for this block */
2118                 down_read(&EXT4_I(inode)->i_data_sem);
2119
2120                 if (path && ext_depth(inode) != depth) {
2121                         /* depth was changed. we have to realloc path */
2122                         kfree(path);
2123                         path = NULL;
2124                 }
2125
2126                 path = ext4_ext_find_extent(inode, block, path, 0);
2127                 if (IS_ERR(path)) {
2128                         up_read(&EXT4_I(inode)->i_data_sem);
2129                         err = PTR_ERR(path);
2130                         path = NULL;
2131                         break;
2132                 }
2133
2134                 depth = ext_depth(inode);
2135                 if (unlikely(path[depth].p_hdr == NULL)) {
2136                         up_read(&EXT4_I(inode)->i_data_sem);
2137                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2138                         err = -EIO;
2139                         break;
2140                 }
2141                 ex = path[depth].p_ext;
2142                 next = ext4_ext_next_allocated_block(path);
2143                 ext4_ext_drop_refs(path);
2144
2145                 flags = 0;
2146                 exists = 0;
2147                 if (!ex) {
2148                         /* there is no extent yet, so try to allocate
2149                          * all requested space */
2150                         start = block;
2151                         end = block + num;
2152                 } else if (le32_to_cpu(ex->ee_block) > block) {
2153                         /* need to allocate space before found extent */
2154                         start = block;
2155                         end = le32_to_cpu(ex->ee_block);
2156                         if (block + num < end)
2157                                 end = block + num;
2158                 } else if (block >= le32_to_cpu(ex->ee_block)
2159                                         + ext4_ext_get_actual_len(ex)) {
2160                         /* need to allocate space after found extent */
2161                         start = block;
2162                         end = block + num;
2163                         if (end >= next)
2164                                 end = next;
2165                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2166                         /*
2167                          * some part of requested space is covered
2168                          * by found extent
2169                          */
2170                         start = block;
2171                         end = le32_to_cpu(ex->ee_block)
2172                                 + ext4_ext_get_actual_len(ex);
2173                         if (block + num < end)
2174                                 end = block + num;
2175                         exists = 1;
2176                 } else {
2177                         BUG();
2178                 }
2179                 BUG_ON(end <= start);
2180
2181                 if (!exists) {
2182                         es.es_lblk = start;
2183                         es.es_len = end - start;
2184                         es.es_pblk = 0;
2185                 } else {
2186                         es.es_lblk = le32_to_cpu(ex->ee_block);
2187                         es.es_len = ext4_ext_get_actual_len(ex);
2188                         es.es_pblk = ext4_ext_pblock(ex);
2189                         if (ext4_ext_is_uninitialized(ex))
2190                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2191                 }
2192
2193                 /*
2194                  * Find delayed extent and update es accordingly. We call
2195                  * it even in !exists case to find out whether es is the
2196                  * last existing extent or not.
2197                  */
2198                 next_del = ext4_find_delayed_extent(inode, &es);
2199                 if (!exists && next_del) {
2200                         exists = 1;
2201                         flags |= (FIEMAP_EXTENT_DELALLOC |
2202                                   FIEMAP_EXTENT_UNKNOWN);
2203                 }
2204                 up_read(&EXT4_I(inode)->i_data_sem);
2205
2206                 if (unlikely(es.es_len == 0)) {
2207                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2208                         err = -EIO;
2209                         break;
2210                 }
2211
2212                 /*
2213                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2214                  * we need to check next == EXT_MAX_BLOCKS because it is
2215                  * possible that an extent is with unwritten and delayed
2216                  * status due to when an extent is delayed allocated and
2217                  * is allocated by fallocate status tree will track both of
2218                  * them in a extent.
2219                  *
2220                  * So we could return a unwritten and delayed extent, and
2221                  * its block is equal to 'next'.
2222                  */
2223                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2224                         flags |= FIEMAP_EXTENT_LAST;
2225                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2226                                      next != EXT_MAX_BLOCKS)) {
2227                                 EXT4_ERROR_INODE(inode,
2228                                                  "next extent == %u, next "
2229                                                  "delalloc extent = %u",
2230                                                  next, next_del);
2231                                 err = -EIO;
2232                                 break;
2233                         }
2234                 }
2235
2236                 if (exists) {
2237                         err = fiemap_fill_next_extent(fieinfo,
2238                                 (__u64)es.es_lblk << blksize_bits,
2239                                 (__u64)es.es_pblk << blksize_bits,
2240                                 (__u64)es.es_len << blksize_bits,
2241                                 flags);
2242                         if (err < 0)
2243                                 break;
2244                         if (err == 1) {
2245                                 err = 0;
2246                                 break;
2247                         }
2248                 }
2249
2250                 block = es.es_lblk + es.es_len;
2251         }
2252
2253         if (path) {
2254                 ext4_ext_drop_refs(path);
2255                 kfree(path);
2256         }
2257
2258         return err;
2259 }
2260
2261 /*
2262  * ext4_ext_put_gap_in_cache:
2263  * calculate boundaries of the gap that the requested block fits into
2264  * and cache this gap
2265  */
2266 static void
2267 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
2268                                 ext4_lblk_t block)
2269 {
2270         int depth = ext_depth(inode);
2271         unsigned long len = 0;
2272         ext4_lblk_t lblock = 0;
2273         struct ext4_extent *ex;
2274
2275         ex = path[depth].p_ext;
2276         if (ex == NULL) {
2277                 /*
2278                  * there is no extent yet, so gap is [0;-] and we
2279                  * don't cache it
2280                  */
2281                 ext_debug("cache gap(whole file):");
2282         } else if (block < le32_to_cpu(ex->ee_block)) {
2283                 lblock = block;
2284                 len = le32_to_cpu(ex->ee_block) - block;
2285                 ext_debug("cache gap(before): %u [%u:%u]",
2286                                 block,
2287                                 le32_to_cpu(ex->ee_block),
2288                                  ext4_ext_get_actual_len(ex));
2289                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2290                         ext4_es_insert_extent(inode, lblock, len, ~0,
2291                                               EXTENT_STATUS_HOLE);
2292         } else if (block >= le32_to_cpu(ex->ee_block)
2293                         + ext4_ext_get_actual_len(ex)) {
2294                 ext4_lblk_t next;
2295                 lblock = le32_to_cpu(ex->ee_block)
2296                         + ext4_ext_get_actual_len(ex);
2297
2298                 next = ext4_ext_next_allocated_block(path);
2299                 ext_debug("cache gap(after): [%u:%u] %u",
2300                                 le32_to_cpu(ex->ee_block),
2301                                 ext4_ext_get_actual_len(ex),
2302                                 block);
2303                 BUG_ON(next == lblock);
2304                 len = next - lblock;
2305                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2306                         ext4_es_insert_extent(inode, lblock, len, ~0,
2307                                               EXTENT_STATUS_HOLE);
2308         } else {
2309                 BUG();
2310         }
2311
2312         ext_debug(" -> %u:%lu\n", lblock, len);
2313 }
2314
2315 /*
2316  * ext4_ext_rm_idx:
2317  * removes index from the index block.
2318  */
2319 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2320                         struct ext4_ext_path *path, int depth)
2321 {
2322         int err;
2323         ext4_fsblk_t leaf;
2324
2325         /* free index block */
2326         depth--;
2327         path = path + depth;
2328         leaf = ext4_idx_pblock(path->p_idx);
2329         if (unlikely(path->p_hdr->eh_entries == 0)) {
2330                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2331                 return -EIO;
2332         }
2333         err = ext4_ext_get_access(handle, inode, path);
2334         if (err)
2335                 return err;
2336
2337         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2338                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2339                 len *= sizeof(struct ext4_extent_idx);
2340                 memmove(path->p_idx, path->p_idx + 1, len);
2341         }
2342
2343         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2344         err = ext4_ext_dirty(handle, inode, path);
2345         if (err)
2346                 return err;
2347         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2348         trace_ext4_ext_rm_idx(inode, leaf);
2349
2350         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2351                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2352
2353         while (--depth >= 0) {
2354                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2355                         break;
2356                 path--;
2357                 err = ext4_ext_get_access(handle, inode, path);
2358                 if (err)
2359                         break;
2360                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2361                 err = ext4_ext_dirty(handle, inode, path);
2362                 if (err)
2363                         break;
2364         }
2365         return err;
2366 }
2367
2368 /*
2369  * ext4_ext_calc_credits_for_single_extent:
2370  * This routine returns max. credits that needed to insert an extent
2371  * to the extent tree.
2372  * When pass the actual path, the caller should calculate credits
2373  * under i_data_sem.
2374  */
2375 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2376                                                 struct ext4_ext_path *path)
2377 {
2378         if (path) {
2379                 int depth = ext_depth(inode);
2380                 int ret = 0;
2381
2382                 /* probably there is space in leaf? */
2383                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2384                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2385
2386                         /*
2387                          *  There are some space in the leaf tree, no
2388                          *  need to account for leaf block credit
2389                          *
2390                          *  bitmaps and block group descriptor blocks
2391                          *  and other metadata blocks still need to be
2392                          *  accounted.
2393                          */
2394                         /* 1 bitmap, 1 block group descriptor */
2395                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2396                         return ret;
2397                 }
2398         }
2399
2400         return ext4_chunk_trans_blocks(inode, nrblocks);
2401 }
2402
2403 /*
2404  * How many index/leaf blocks need to change/allocate to add @extents extents?
2405  *
2406  * If we add a single extent, then in the worse case, each tree level
2407  * index/leaf need to be changed in case of the tree split.
2408  *
2409  * If more extents are inserted, they could cause the whole tree split more
2410  * than once, but this is really rare.
2411  */
2412 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2413 {
2414         int index;
2415         int depth;
2416
2417         /* If we are converting the inline data, only one is needed here. */
2418         if (ext4_has_inline_data(inode))
2419                 return 1;
2420
2421         depth = ext_depth(inode);
2422
2423         if (extents <= 1)
2424                 index = depth * 2;
2425         else
2426                 index = depth * 3;
2427
2428         return index;
2429 }
2430
2431 static inline int get_default_free_blocks_flags(struct inode *inode)
2432 {
2433         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2434                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2435         else if (ext4_should_journal_data(inode))
2436                 return EXT4_FREE_BLOCKS_FORGET;
2437         return 0;
2438 }
2439
2440 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2441                               struct ext4_extent *ex,
2442                               long long *partial_cluster,
2443                               ext4_lblk_t from, ext4_lblk_t to)
2444 {
2445         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2446         unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2447         ext4_fsblk_t pblk;
2448         int flags = get_default_free_blocks_flags(inode);
2449
2450         /*
2451          * For bigalloc file systems, we never free a partial cluster
2452          * at the beginning of the extent.  Instead, we make a note
2453          * that we tried freeing the cluster, and check to see if we
2454          * need to free it on a subsequent call to ext4_remove_blocks,
2455          * or at the end of the ext4_truncate() operation.
2456          */
2457         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2458
2459         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2460         /*
2461          * If we have a partial cluster, and it's different from the
2462          * cluster of the last block, we need to explicitly free the
2463          * partial cluster here.
2464          */
2465         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2466         if ((*partial_cluster > 0) &&
2467             (EXT4_B2C(sbi, pblk) != *partial_cluster)) {
2468                 ext4_free_blocks(handle, inode, NULL,
2469                                  EXT4_C2B(sbi, *partial_cluster),
2470                                  sbi->s_cluster_ratio, flags);
2471                 *partial_cluster = 0;
2472         }
2473
2474 #ifdef EXTENTS_STATS
2475         {
2476                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2477                 spin_lock(&sbi->s_ext_stats_lock);
2478                 sbi->s_ext_blocks += ee_len;
2479                 sbi->s_ext_extents++;
2480                 if (ee_len < sbi->s_ext_min)
2481                         sbi->s_ext_min = ee_len;
2482                 if (ee_len > sbi->s_ext_max)
2483                         sbi->s_ext_max = ee_len;
2484                 if (ext_depth(inode) > sbi->s_depth_max)
2485                         sbi->s_depth_max = ext_depth(inode);
2486                 spin_unlock(&sbi->s_ext_stats_lock);
2487         }
2488 #endif
2489         if (from >= le32_to_cpu(ex->ee_block)
2490             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2491                 /* tail removal */
2492                 ext4_lblk_t num;
2493                 unsigned int unaligned;
2494
2495                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2496                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2497                 /*
2498                  * Usually we want to free partial cluster at the end of the
2499                  * extent, except for the situation when the cluster is still
2500                  * used by any other extent (partial_cluster is negative).
2501                  */
2502                 if (*partial_cluster < 0 &&
2503                     -(*partial_cluster) == EXT4_B2C(sbi, pblk + num - 1))
2504                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2505
2506                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2507                           num, pblk, *partial_cluster);
2508                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2509                 /*
2510                  * If the block range to be freed didn't start at the
2511                  * beginning of a cluster, and we removed the entire
2512                  * extent and the cluster is not used by any other extent,
2513                  * save the partial cluster here, since we might need to
2514                  * delete if we determine that the truncate operation has
2515                  * removed all of the blocks in the cluster.
2516                  *
2517                  * On the other hand, if we did not manage to free the whole
2518                  * extent, we have to mark the cluster as used (store negative
2519                  * cluster number in partial_cluster).
2520                  */
2521                 unaligned = EXT4_PBLK_COFF(sbi, pblk);
2522                 if (unaligned && (ee_len == num) &&
2523                     (*partial_cluster != -((long long)EXT4_B2C(sbi, pblk))))
2524                         *partial_cluster = EXT4_B2C(sbi, pblk);
2525                 else if (unaligned)
2526                         *partial_cluster = -((long long)EXT4_B2C(sbi, pblk));
2527                 else if (*partial_cluster > 0)
2528                         *partial_cluster = 0;
2529         } else
2530                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2531                            "%u-%u from %u:%u\n",
2532                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2533         return 0;
2534 }
2535
2536
2537 /*
2538  * ext4_ext_rm_leaf() Removes the extents associated with the
2539  * blocks appearing between "start" and "end", and splits the extents
2540  * if "start" and "end" appear in the same extent
2541  *
2542  * @handle: The journal handle
2543  * @inode:  The files inode
2544  * @path:   The path to the leaf
2545  * @partial_cluster: The cluster which we'll have to free if all extents
2546  *                   has been released from it. It gets negative in case
2547  *                   that the cluster is still used.
2548  * @start:  The first block to remove
2549  * @end:   The last block to remove
2550  */
2551 static int
2552 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2553                  struct ext4_ext_path *path,
2554                  long long *partial_cluster,
2555                  ext4_lblk_t start, ext4_lblk_t end)
2556 {
2557         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2558         int err = 0, correct_index = 0;
2559         int depth = ext_depth(inode), credits;
2560         struct ext4_extent_header *eh;
2561         ext4_lblk_t a, b;
2562         unsigned num;
2563         ext4_lblk_t ex_ee_block;
2564         unsigned short ex_ee_len;
2565         unsigned uninitialized = 0;
2566         struct ext4_extent *ex;
2567         ext4_fsblk_t pblk;
2568
2569         /* the header must be checked already in ext4_ext_remove_space() */
2570         ext_debug("truncate since %u in leaf to %u\n", start, end);
2571         if (!path[depth].p_hdr)
2572                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2573         eh = path[depth].p_hdr;
2574         if (unlikely(path[depth].p_hdr == NULL)) {
2575                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2576                 return -EIO;
2577         }
2578         /* find where to start removing */
2579         ex = path[depth].p_ext;
2580         if (!ex)
2581                 ex = EXT_LAST_EXTENT(eh);
2582
2583         ex_ee_block = le32_to_cpu(ex->ee_block);
2584         ex_ee_len = ext4_ext_get_actual_len(ex);
2585
2586         /*
2587          * If we're starting with an extent other than the last one in the
2588          * node, we need to see if it shares a cluster with the extent to
2589          * the right (towards the end of the file). If its leftmost cluster
2590          * is this extent's rightmost cluster and it is not cluster aligned,
2591          * we'll mark it as a partial that is not to be deallocated.
2592          */
2593
2594         if (ex != EXT_LAST_EXTENT(eh)) {
2595                 ext4_fsblk_t current_pblk, right_pblk;
2596                 long long current_cluster, right_cluster;
2597
2598                 current_pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2599                 current_cluster = (long long)EXT4_B2C(sbi, current_pblk);
2600                 right_pblk = ext4_ext_pblock(ex + 1);
2601                 right_cluster = (long long)EXT4_B2C(sbi, right_pblk);
2602                 if (current_cluster == right_cluster &&
2603                         EXT4_PBLK_COFF(sbi, right_pblk))
2604                         *partial_cluster = -right_cluster;
2605         }
2606
2607         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2608
2609         while (ex >= EXT_FIRST_EXTENT(eh) &&
2610                         ex_ee_block + ex_ee_len > start) {
2611
2612                 if (ext4_ext_is_uninitialized(ex))
2613                         uninitialized = 1;
2614                 else
2615                         uninitialized = 0;
2616
2617                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2618                          uninitialized, ex_ee_len);
2619                 path[depth].p_ext = ex;
2620
2621                 a = ex_ee_block > start ? ex_ee_block : start;
2622                 b = ex_ee_block+ex_ee_len - 1 < end ?
2623                         ex_ee_block+ex_ee_len - 1 : end;
2624
2625                 ext_debug("  border %u:%u\n", a, b);
2626
2627                 /* If this extent is beyond the end of the hole, skip it */
2628                 if (end < ex_ee_block) {
2629                         /*
2630                          * We're going to skip this extent and move to another,
2631                          * so if this extent is not cluster aligned we have
2632                          * to mark the current cluster as used to avoid
2633                          * accidentally freeing it later on
2634                          */
2635                         pblk = ext4_ext_pblock(ex);
2636                         if (EXT4_PBLK_COFF(sbi, pblk))
2637                                 *partial_cluster =
2638                                         -((long long)EXT4_B2C(sbi, pblk));
2639                         ex--;
2640                         ex_ee_block = le32_to_cpu(ex->ee_block);
2641                         ex_ee_len = ext4_ext_get_actual_len(ex);
2642                         continue;
2643                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2644                         EXT4_ERROR_INODE(inode,
2645                                          "can not handle truncate %u:%u "
2646                                          "on extent %u:%u",
2647                                          start, end, ex_ee_block,
2648                                          ex_ee_block + ex_ee_len - 1);
2649                         err = -EIO;
2650                         goto out;
2651                 } else if (a != ex_ee_block) {
2652                         /* remove tail of the extent */
2653                         num = a - ex_ee_block;
2654                 } else {
2655                         /* remove whole extent: excellent! */
2656                         num = 0;
2657                 }
2658                 /*
2659                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2660                  * descriptor) for each block group; assume two block
2661                  * groups plus ex_ee_len/blocks_per_block_group for
2662                  * the worst case
2663                  */
2664                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2665                 if (ex == EXT_FIRST_EXTENT(eh)) {
2666                         correct_index = 1;
2667                         credits += (ext_depth(inode)) + 1;
2668                 }
2669                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2670
2671                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2672                 if (err)
2673                         goto out;
2674
2675                 err = ext4_ext_get_access(handle, inode, path + depth);
2676                 if (err)
2677                         goto out;
2678
2679                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2680                                          a, b);
2681                 if (err)
2682                         goto out;
2683
2684                 if (num == 0)
2685                         /* this extent is removed; mark slot entirely unused */
2686                         ext4_ext_store_pblock(ex, 0);
2687
2688                 ex->ee_len = cpu_to_le16(num);
2689                 /*
2690                  * Do not mark uninitialized if all the blocks in the
2691                  * extent have been removed.
2692                  */
2693                 if (uninitialized && num)
2694                         ext4_ext_mark_uninitialized(ex);
2695                 /*
2696                  * If the extent was completely released,
2697                  * we need to remove it from the leaf
2698                  */
2699                 if (num == 0) {
2700                         if (end != EXT_MAX_BLOCKS - 1) {
2701                                 /*
2702                                  * For hole punching, we need to scoot all the
2703                                  * extents up when an extent is removed so that
2704                                  * we dont have blank extents in the middle
2705                                  */
2706                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2707                                         sizeof(struct ext4_extent));
2708
2709                                 /* Now get rid of the one at the end */
2710                                 memset(EXT_LAST_EXTENT(eh), 0,
2711                                         sizeof(struct ext4_extent));
2712                         }
2713                         le16_add_cpu(&eh->eh_entries, -1);
2714                 } else if (*partial_cluster > 0)
2715                         *partial_cluster = 0;
2716
2717                 err = ext4_ext_dirty(handle, inode, path + depth);
2718                 if (err)
2719                         goto out;
2720
2721                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2722                                 ext4_ext_pblock(ex));
2723                 ex--;
2724                 ex_ee_block = le32_to_cpu(ex->ee_block);
2725                 ex_ee_len = ext4_ext_get_actual_len(ex);
2726         }
2727
2728         if (correct_index && eh->eh_entries)
2729                 err = ext4_ext_correct_indexes(handle, inode, path);
2730
2731         /*
2732          * If there's a partial cluster and at least one extent remains in
2733          * the leaf, free the partial cluster if it isn't shared with the
2734          * current extent.  If there's a partial cluster and no extents
2735          * remain in the leaf, it can't be freed here.  It can only be
2736          * freed when it's possible to determine if it's not shared with
2737          * any other extent - when the next leaf is processed or when space
2738          * removal is complete.
2739          */
2740         if (*partial_cluster > 0 && eh->eh_entries &&
2741             (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) !=
2742              *partial_cluster)) {
2743                 int flags = get_default_free_blocks_flags(inode);
2744
2745                 ext4_free_blocks(handle, inode, NULL,
2746                                  EXT4_C2B(sbi, *partial_cluster),
2747                                  sbi->s_cluster_ratio, flags);
2748                 *partial_cluster = 0;
2749         }
2750
2751         /* if this leaf is free, then we should
2752          * remove it from index block above */
2753         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2754                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2755
2756 out:
2757         return err;
2758 }
2759
2760 /*
2761  * ext4_ext_more_to_rm:
2762  * returns 1 if current index has to be freed (even partial)
2763  */
2764 static int
2765 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2766 {
2767         BUG_ON(path->p_idx == NULL);
2768
2769         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2770                 return 0;
2771
2772         /*
2773          * if truncate on deeper level happened, it wasn't partial,
2774          * so we have to consider current index for truncation
2775          */
2776         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2777                 return 0;
2778         return 1;
2779 }
2780
2781 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2782                           ext4_lblk_t end)
2783 {
2784         struct super_block *sb = inode->i_sb;
2785         int depth = ext_depth(inode);
2786         struct ext4_ext_path *path = NULL;
2787         long long partial_cluster = 0;
2788         handle_t *handle;
2789         int i = 0, err = 0;
2790
2791         ext_debug("truncate since %u to %u\n", start, end);
2792
2793         /* probably first extent we're gonna free will be last in block */
2794         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2795         if (IS_ERR(handle))
2796                 return PTR_ERR(handle);
2797
2798 again:
2799         trace_ext4_ext_remove_space(inode, start, end, depth);
2800
2801         /*
2802          * Check if we are removing extents inside the extent tree. If that
2803          * is the case, we are going to punch a hole inside the extent tree
2804          * so we have to check whether we need to split the extent covering
2805          * the last block to remove so we can easily remove the part of it
2806          * in ext4_ext_rm_leaf().
2807          */
2808         if (end < EXT_MAX_BLOCKS - 1) {
2809                 struct ext4_extent *ex;
2810                 ext4_lblk_t ee_block;
2811
2812                 /* find extent for this block */
2813                 path = ext4_ext_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2814                 if (IS_ERR(path)) {
2815                         ext4_journal_stop(handle);
2816                         return PTR_ERR(path);
2817                 }
2818                 depth = ext_depth(inode);
2819                 /* Leaf not may not exist only if inode has no blocks at all */
2820                 ex = path[depth].p_ext;
2821                 if (!ex) {
2822                         if (depth) {
2823                                 EXT4_ERROR_INODE(inode,
2824                                                  "path[%d].p_hdr == NULL",
2825                                                  depth);
2826                                 err = -EIO;
2827                         }
2828                         goto out;
2829                 }
2830
2831                 ee_block = le32_to_cpu(ex->ee_block);
2832
2833                 /*
2834                  * See if the last block is inside the extent, if so split
2835                  * the extent at 'end' block so we can easily remove the
2836                  * tail of the first part of the split extent in
2837                  * ext4_ext_rm_leaf().
2838                  */
2839                 if (end >= ee_block &&
2840                     end < ee_block + ext4_ext_get_actual_len(ex) - 1) {
2841                         int split_flag = 0;
2842
2843                         if (ext4_ext_is_uninitialized(ex))
2844                                 split_flag = EXT4_EXT_MARK_UNINIT1 |
2845                                              EXT4_EXT_MARK_UNINIT2;
2846
2847                         /*
2848                          * Split the extent in two so that 'end' is the last
2849                          * block in the first new extent. Also we should not
2850                          * fail removing space due to ENOSPC so try to use
2851                          * reserved block if that happens.
2852                          */
2853                         err = ext4_split_extent_at(handle, inode, path,
2854                                         end + 1, split_flag,
2855                                         EXT4_EX_NOCACHE |
2856                                         EXT4_GET_BLOCKS_PRE_IO |
2857                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
2858
2859                         if (err < 0)
2860                                 goto out;
2861                 }
2862         }
2863         /*
2864          * We start scanning from right side, freeing all the blocks
2865          * after i_size and walking into the tree depth-wise.
2866          */
2867         depth = ext_depth(inode);
2868         if (path) {
2869                 int k = i = depth;
2870                 while (--k > 0)
2871                         path[k].p_block =
2872                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2873         } else {
2874                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2875                                GFP_NOFS);
2876                 if (path == NULL) {
2877                         ext4_journal_stop(handle);
2878                         return -ENOMEM;
2879                 }
2880                 path[0].p_depth = depth;
2881                 path[0].p_hdr = ext_inode_hdr(inode);
2882                 i = 0;
2883
2884                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2885                         err = -EIO;
2886                         goto out;
2887                 }
2888         }
2889         err = 0;
2890
2891         while (i >= 0 && err == 0) {
2892                 if (i == depth) {
2893                         /* this is leaf block */
2894                         err = ext4_ext_rm_leaf(handle, inode, path,
2895                                                &partial_cluster, start,
2896                                                end);
2897                         /* root level has p_bh == NULL, brelse() eats this */
2898                         brelse(path[i].p_bh);
2899                         path[i].p_bh = NULL;
2900                         i--;
2901                         continue;
2902                 }
2903
2904                 /* this is index block */
2905                 if (!path[i].p_hdr) {
2906                         ext_debug("initialize header\n");
2907                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2908                 }
2909
2910                 if (!path[i].p_idx) {
2911                         /* this level hasn't been touched yet */
2912                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2913                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2914                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2915                                   path[i].p_hdr,
2916                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2917                 } else {
2918                         /* we were already here, see at next index */
2919                         path[i].p_idx--;
2920                 }
2921
2922                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2923                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2924                                 path[i].p_idx);
2925                 if (ext4_ext_more_to_rm(path + i)) {
2926                         struct buffer_head *bh;
2927                         /* go to the next level */
2928                         ext_debug("move to level %d (block %llu)\n",
2929                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2930                         memset(path + i + 1, 0, sizeof(*path));
2931                         bh = read_extent_tree_block(inode,
2932                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2933                                 EXT4_EX_NOCACHE);
2934                         if (IS_ERR(bh)) {
2935                                 /* should we reset i_size? */
2936                                 err = PTR_ERR(bh);
2937                                 break;
2938                         }
2939                         /* Yield here to deal with large extent trees.
2940                          * Should be a no-op if we did IO above. */
2941                         cond_resched();
2942                         if (WARN_ON(i + 1 > depth)) {
2943                                 err = -EIO;
2944                                 break;
2945                         }
2946                         path[i + 1].p_bh = bh;
2947
2948                         /* save actual number of indexes since this
2949                          * number is changed at the next iteration */
2950                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2951                         i++;
2952                 } else {
2953                         /* we finished processing this index, go up */
2954                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2955                                 /* index is empty, remove it;
2956                                  * handle must be already prepared by the
2957                                  * truncatei_leaf() */
2958                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2959                         }
2960                         /* root level has p_bh == NULL, brelse() eats this */
2961                         brelse(path[i].p_bh);
2962                         path[i].p_bh = NULL;
2963                         i--;
2964                         ext_debug("return to level %d\n", i);
2965                 }
2966         }
2967
2968         trace_ext4_ext_remove_space_done(inode, start, end, depth,
2969                         partial_cluster, path->p_hdr->eh_entries);
2970
2971         /* If we still have something in the partial cluster and we have removed
2972          * even the first extent, then we should free the blocks in the partial
2973          * cluster as well. */
2974         if (partial_cluster > 0 && path->p_hdr->eh_entries == 0) {
2975                 int flags = get_default_free_blocks_flags(inode);
2976
2977                 ext4_free_blocks(handle, inode, NULL,
2978                                  EXT4_C2B(EXT4_SB(sb), partial_cluster),
2979                                  EXT4_SB(sb)->s_cluster_ratio, flags);
2980                 partial_cluster = 0;
2981         }
2982
2983         /* TODO: flexible tree reduction should be here */
2984         if (path->p_hdr->eh_entries == 0) {
2985                 /*
2986                  * truncate to zero freed all the tree,
2987                  * so we need to correct eh_depth
2988                  */
2989                 err = ext4_ext_get_access(handle, inode, path);
2990                 if (err == 0) {
2991                         ext_inode_hdr(inode)->eh_depth = 0;
2992                         ext_inode_hdr(inode)->eh_max =
2993                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
2994                         err = ext4_ext_dirty(handle, inode, path);
2995                 }
2996         }
2997 out:
2998         ext4_ext_drop_refs(path);
2999         kfree(path);
3000         if (err == -EAGAIN) {
3001                 path = NULL;
3002                 goto again;
3003         }
3004         ext4_journal_stop(handle);
3005
3006         return err;
3007 }
3008
3009 /*
3010  * called at mount time
3011  */
3012 void ext4_ext_init(struct super_block *sb)
3013 {
3014         /*
3015          * possible initialization would be here
3016          */
3017
3018         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
3019 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3020                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3021 #ifdef AGGRESSIVE_TEST
3022                        ", aggressive tests"
3023 #endif
3024 #ifdef CHECK_BINSEARCH
3025                        ", check binsearch"
3026 #endif
3027 #ifdef EXTENTS_STATS
3028                        ", stats"
3029 #endif
3030                        "\n");
3031 #endif
3032 #ifdef EXTENTS_STATS
3033                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3034                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3035                 EXT4_SB(sb)->s_ext_max = 0;
3036 #endif
3037         }
3038 }
3039
3040 /*
3041  * called at umount time
3042  */
3043 void ext4_ext_release(struct super_block *sb)
3044 {
3045         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
3046                 return;
3047
3048 #ifdef EXTENTS_STATS
3049         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3050                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3051                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3052                         sbi->s_ext_blocks, sbi->s_ext_extents,
3053                         sbi->s_ext_blocks / sbi->s_ext_extents);
3054                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3055                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3056         }
3057 #endif
3058 }
3059
3060 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3061 {
3062         ext4_lblk_t  ee_block;
3063         ext4_fsblk_t ee_pblock;
3064         unsigned int ee_len;
3065
3066         ee_block  = le32_to_cpu(ex->ee_block);
3067         ee_len    = ext4_ext_get_actual_len(ex);
3068         ee_pblock = ext4_ext_pblock(ex);
3069
3070         if (ee_len == 0)
3071                 return 0;
3072
3073         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3074                                      EXTENT_STATUS_WRITTEN);
3075 }
3076
3077 /* FIXME!! we need to try to merge to left or right after zero-out  */
3078 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3079 {
3080         ext4_fsblk_t ee_pblock;
3081         unsigned int ee_len;
3082         int ret;
3083
3084         ee_len    = ext4_ext_get_actual_len(ex);
3085         ee_pblock = ext4_ext_pblock(ex);
3086
3087         ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
3088         if (ret > 0)
3089                 ret = 0;
3090
3091         return ret;
3092 }
3093
3094 /*
3095  * ext4_split_extent_at() splits an extent at given block.
3096  *
3097  * @handle: the journal handle
3098  * @inode: the file inode
3099  * @path: the path to the extent
3100  * @split: the logical block where the extent is splitted.
3101  * @split_flags: indicates if the extent could be zeroout if split fails, and
3102  *               the states(init or uninit) of new extents.
3103  * @flags: flags used to insert new extent to extent tree.
3104  *
3105  *
3106  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3107  * of which are deterimined by split_flag.
3108  *
3109  * There are two cases:
3110  *  a> the extent are splitted into two extent.
3111  *  b> split is not needed, and just mark the extent.
3112  *
3113  * return 0 on success.
3114  */
3115 static int ext4_split_extent_at(handle_t *handle,
3116                              struct inode *inode,
3117                              struct ext4_ext_path *path,
3118                              ext4_lblk_t split,
3119                              int split_flag,
3120                              int flags)
3121 {
3122         ext4_fsblk_t newblock;
3123         ext4_lblk_t ee_block;
3124         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3125         struct ext4_extent *ex2 = NULL;
3126         unsigned int ee_len, depth;
3127         int err = 0;
3128
3129         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3130                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3131
3132         ext_debug("ext4_split_extents_at: inode %lu, logical"
3133                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3134
3135         ext4_ext_show_leaf(inode, path);
3136
3137         depth = ext_depth(inode);
3138         ex = path[depth].p_ext;
3139         ee_block = le32_to_cpu(ex->ee_block);
3140         ee_len = ext4_ext_get_actual_len(ex);
3141         newblock = split - ee_block + ext4_ext_pblock(ex);
3142
3143         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3144         BUG_ON(!ext4_ext_is_uninitialized(ex) &&
3145                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3146                              EXT4_EXT_MARK_UNINIT1 |
3147                              EXT4_EXT_MARK_UNINIT2));
3148
3149         err = ext4_ext_get_access(handle, inode, path + depth);
3150         if (err)
3151                 goto out;
3152
3153         if (split == ee_block) {
3154                 /*
3155                  * case b: block @split is the block that the extent begins with
3156                  * then we just change the state of the extent, and splitting
3157                  * is not needed.
3158                  */
3159                 if (split_flag & EXT4_EXT_MARK_UNINIT2)
3160                         ext4_ext_mark_uninitialized(ex);
3161                 else
3162                         ext4_ext_mark_initialized(ex);
3163
3164                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3165                         ext4_ext_try_to_merge(handle, inode, path, ex);
3166
3167                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3168                 goto out;
3169         }
3170
3171         /* case a */
3172         memcpy(&orig_ex, ex, sizeof(orig_ex));
3173         ex->ee_len = cpu_to_le16(split - ee_block);
3174         if (split_flag & EXT4_EXT_MARK_UNINIT1)
3175                 ext4_ext_mark_uninitialized(ex);
3176
3177         /*
3178          * path may lead to new leaf, not to original leaf any more
3179          * after ext4_ext_insert_extent() returns,
3180          */
3181         err = ext4_ext_dirty(handle, inode, path + depth);
3182         if (err)
3183                 goto fix_extent_len;
3184
3185         ex2 = &newex;
3186         ex2->ee_block = cpu_to_le32(split);
3187         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3188         ext4_ext_store_pblock(ex2, newblock);
3189         if (split_flag & EXT4_EXT_MARK_UNINIT2)
3190                 ext4_ext_mark_uninitialized(ex2);
3191
3192         err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
3193         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3194                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3195                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3196                                 err = ext4_ext_zeroout(inode, ex2);
3197                                 zero_ex.ee_block = ex2->ee_block;
3198                                 zero_ex.ee_len = cpu_to_le16(
3199                                                 ext4_ext_get_actual_len(ex2));
3200                                 ext4_ext_store_pblock(&zero_ex,
3201                                                       ext4_ext_pblock(ex2));
3202                         } else {
3203                                 err = ext4_ext_zeroout(inode, ex);
3204                                 zero_ex.ee_block = ex->ee_block;
3205                                 zero_ex.ee_len = cpu_to_le16(
3206                                                 ext4_ext_get_actual_len(ex));
3207                                 ext4_ext_store_pblock(&zero_ex,
3208                                                       ext4_ext_pblock(ex));
3209                         }
3210                 } else {
3211                         err = ext4_ext_zeroout(inode, &orig_ex);
3212                         zero_ex.ee_block = orig_ex.ee_block;
3213                         zero_ex.ee_len = cpu_to_le16(
3214                                                 ext4_ext_get_actual_len(&orig_ex));
3215                         ext4_ext_store_pblock(&zero_ex,
3216                                               ext4_ext_pblock(&orig_ex));
3217                 }
3218
3219                 if (err)
3220                         goto fix_extent_len;
3221                 /* update the extent length and mark as initialized */
3222                 ex->ee_len = cpu_to_le16(ee_len);
3223                 ext4_ext_try_to_merge(handle, inode, path, ex);
3224                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3225                 if (err)
3226                         goto fix_extent_len;
3227
3228                 /* update extent status tree */
3229                 err = ext4_zeroout_es(inode, &zero_ex);
3230
3231                 goto out;
3232         } else if (err)
3233                 goto fix_extent_len;
3234
3235 out:
3236         ext4_ext_show_leaf(inode, path);
3237         return err;
3238
3239 fix_extent_len:
3240         ex->ee_len = orig_ex.ee_len;
3241         ext4_ext_dirty(handle, inode, path + depth);
3242         return err;
3243 }
3244
3245 /*
3246  * ext4_split_extents() splits an extent and mark extent which is covered
3247  * by @map as split_flags indicates
3248  *
3249  * It may result in splitting the extent into multiple extents (up to three)
3250  * There are three possibilities:
3251  *   a> There is no split required
3252  *   b> Splits in two extents: Split is happening at either end of the extent
3253  *   c> Splits in three extents: Somone is splitting in middle of the extent
3254  *
3255  */
3256 static int ext4_split_extent(handle_t *handle,
3257                               struct inode *inode,
3258                               struct ext4_ext_path *path,
3259                               struct ext4_map_blocks *map,
3260                               int split_flag,
3261                               int flags)
3262 {
3263         ext4_lblk_t ee_block;
3264         struct ext4_extent *ex;
3265         unsigned int ee_len, depth;
3266         int err = 0;
3267         int uninitialized;
3268         int split_flag1, flags1;
3269         int allocated = map->m_len;
3270
3271         depth = ext_depth(inode);
3272         ex = path[depth].p_ext;
3273         ee_block = le32_to_cpu(ex->ee_block);
3274         ee_len = ext4_ext_get_actual_len(ex);
3275         uninitialized = ext4_ext_is_uninitialized(ex);
3276
3277         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3278                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3279                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3280                 if (uninitialized)
3281                         split_flag1 |= EXT4_EXT_MARK_UNINIT1 |
3282                                        EXT4_EXT_MARK_UNINIT2;
3283                 if (split_flag & EXT4_EXT_DATA_VALID2)
3284                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3285                 err = ext4_split_extent_at(handle, inode, path,
3286                                 map->m_lblk + map->m_len, split_flag1, flags1);
3287                 if (err)
3288                         goto out;
3289         } else {
3290                 allocated = ee_len - (map->m_lblk - ee_block);
3291         }
3292         /*
3293          * Update path is required because previous ext4_split_extent_at() may
3294          * result in split of original leaf or extent zeroout.
3295          */
3296         ext4_ext_drop_refs(path);
3297         path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3298         if (IS_ERR(path))
3299                 return PTR_ERR(path);
3300         depth = ext_depth(inode);
3301         ex = path[depth].p_ext;
3302         uninitialized = ext4_ext_is_uninitialized(ex);
3303         split_flag1 = 0;
3304
3305         if (map->m_lblk >= ee_block) {
3306                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3307                 if (uninitialized) {
3308                         split_flag1 |= EXT4_EXT_MARK_UNINIT1;
3309                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3310                                                      EXT4_EXT_MARK_UNINIT2);
3311                 }
3312                 err = ext4_split_extent_at(handle, inode, path,
3313                                 map->m_lblk, split_flag1, flags);
3314                 if (err)
3315                         goto out;
3316         }
3317
3318         ext4_ext_show_leaf(inode, path);
3319 out:
3320         return err ? err : allocated;
3321 }
3322
3323 /*
3324  * This function is called by ext4_ext_map_blocks() if someone tries to write
3325  * to an uninitialized extent. It may result in splitting the uninitialized
3326  * extent into multiple extents (up to three - one initialized and two
3327  * uninitialized).
3328  * There are three possibilities:
3329  *   a> There is no split required: Entire extent should be initialized
3330  *   b> Splits in two extents: Write is happening at either end of the extent
3331  *   c> Splits in three extents: Somone is writing in middle of the extent
3332  *
3333  * Pre-conditions:
3334  *  - The extent pointed to by 'path' is uninitialized.
3335  *  - The extent pointed to by 'path' contains a superset
3336  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3337  *
3338  * Post-conditions on success:
3339  *  - the returned value is the number of blocks beyond map->l_lblk
3340  *    that are allocated and initialized.
3341  *    It is guaranteed to be >= map->m_len.
3342  */
3343 static int ext4_ext_convert_to_initialized(handle_t *handle,
3344                                            struct inode *inode,
3345                                            struct ext4_map_blocks *map,
3346                                            struct ext4_ext_path *path,
3347                                            int flags)
3348 {
3349         struct ext4_sb_info *sbi;
3350         struct ext4_extent_header *eh;
3351         struct ext4_map_blocks split_map;
3352         struct ext4_extent zero_ex;
3353         struct ext4_extent *ex, *abut_ex;
3354         ext4_lblk_t ee_block, eof_block;
3355         unsigned int ee_len, depth, map_len = map->m_len;
3356         int allocated = 0, max_zeroout = 0;
3357         int err = 0;
3358         int split_flag = 0;
3359
3360         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3361                 "block %llu, max_blocks %u\n", inode->i_ino,
3362                 (unsigned long long)map->m_lblk, map_len);
3363
3364         sbi = EXT4_SB(inode->i_sb);
3365         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3366                 inode->i_sb->s_blocksize_bits;
3367         if (eof_block < map->m_lblk + map_len)
3368                 eof_block = map->m_lblk + map_len;
3369
3370         depth = ext_depth(inode);
3371         eh = path[depth].p_hdr;
3372         ex = path[depth].p_ext;
3373         ee_block = le32_to_cpu(ex->ee_block);
3374         ee_len = ext4_ext_get_actual_len(ex);
3375         zero_ex.ee_len = 0;
3376
3377         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3378
3379         /* Pre-conditions */
3380         BUG_ON(!ext4_ext_is_uninitialized(ex));
3381         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3382
3383         /*
3384          * Attempt to transfer newly initialized blocks from the currently
3385          * uninitialized extent to its neighbor. This is much cheaper
3386          * than an insertion followed by a merge as those involve costly
3387          * memmove() calls. Transferring to the left is the common case in
3388          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3389          * followed by append writes.
3390          *
3391          * Limitations of the current logic:
3392          *  - L1: we do not deal with writes covering the whole extent.
3393          *    This would require removing the extent if the transfer
3394          *    is possible.
3395          *  - L2: we only attempt to merge with an extent stored in the
3396          *    same extent tree node.
3397          */
3398         if ((map->m_lblk == ee_block) &&
3399                 /* See if we can merge left */
3400                 (map_len < ee_len) &&           /*L1*/
3401                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3402                 ext4_lblk_t prev_lblk;
3403                 ext4_fsblk_t prev_pblk, ee_pblk;
3404                 unsigned int prev_len;
3405
3406                 abut_ex = ex - 1;
3407                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3408                 prev_len = ext4_ext_get_actual_len(abut_ex);
3409                 prev_pblk = ext4_ext_pblock(abut_ex);
3410                 ee_pblk = ext4_ext_pblock(ex);
3411
3412                 /*
3413                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3414                  * upon those conditions:
3415                  * - C1: abut_ex is initialized,
3416                  * - C2: abut_ex is logically abutting ex,
3417                  * - C3: abut_ex is physically abutting ex,
3418                  * - C4: abut_ex can receive the additional blocks without
3419                  *   overflowing the (initialized) length limit.
3420                  */
3421                 if ((!ext4_ext_is_uninitialized(abut_ex)) &&            /*C1*/
3422                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3423                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3424                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3425                         err = ext4_ext_get_access(handle, inode, path + depth);
3426                         if (err)
3427                                 goto out;
3428
3429                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3430                                 map, ex, abut_ex);
3431
3432                         /* Shift the start of ex by 'map_len' blocks */
3433                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3434                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3435                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3436                         ext4_ext_mark_uninitialized(ex); /* Restore the flag */
3437
3438                         /* Extend abut_ex by 'map_len' blocks */
3439                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3440
3441                         /* Result: number of initialized blocks past m_lblk */
3442                         allocated = map_len;
3443                 }
3444         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3445                    (map_len < ee_len) &&        /*L1*/
3446                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3447                 /* See if we can merge right */
3448                 ext4_lblk_t next_lblk;
3449                 ext4_fsblk_t next_pblk, ee_pblk;
3450                 unsigned int next_len;
3451
3452                 abut_ex = ex + 1;
3453                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3454                 next_len = ext4_ext_get_actual_len(abut_ex);
3455                 next_pblk = ext4_ext_pblock(abut_ex);
3456                 ee_pblk = ext4_ext_pblock(ex);
3457
3458                 /*
3459                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3460                  * upon those conditions:
3461                  * - C1: abut_ex is initialized,
3462                  * - C2: abut_ex is logically abutting ex,
3463                  * - C3: abut_ex is physically abutting ex,
3464                  * - C4: abut_ex can receive the additional blocks without
3465                  *   overflowing the (initialized) length limit.
3466                  */
3467                 if ((!ext4_ext_is_uninitialized(abut_ex)) &&            /*C1*/
3468                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3469                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3470                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3471                         err = ext4_ext_get_access(handle, inode, path + depth);
3472                         if (err)
3473                                 goto out;
3474
3475                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3476                                 map, ex, abut_ex);
3477
3478                         /* Shift the start of abut_ex by 'map_len' blocks */
3479                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3480                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3481                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3482                         ext4_ext_mark_uninitialized(ex); /* Restore the flag */
3483
3484                         /* Extend abut_ex by 'map_len' blocks */
3485                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3486
3487                         /* Result: number of initialized blocks past m_lblk */
3488                         allocated = map_len;
3489                 }
3490         }
3491         if (allocated) {
3492                 /* Mark the block containing both extents as dirty */
3493                 ext4_ext_dirty(handle, inode, path + depth);
3494
3495                 /* Update path to point to the right extent */
3496                 path[depth].p_ext = abut_ex;
3497                 goto out;
3498         } else
3499                 allocated = ee_len - (map->m_lblk - ee_block);
3500
3501         WARN_ON(map->m_lblk < ee_block);
3502         /*
3503          * It is safe to convert extent to initialized via explicit
3504          * zeroout only if extent is fully inside i_size or new_size.
3505          */
3506         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3507
3508         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3509                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3510                         (inode->i_sb->s_blocksize_bits - 10);
3511
3512         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3513         if (max_zeroout && (ee_len <= max_zeroout)) {
3514                 err = ext4_ext_zeroout(inode, ex);
3515                 if (err)
3516                         goto out;
3517                 zero_ex.ee_block = ex->ee_block;
3518                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3519                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3520
3521                 err = ext4_ext_get_access(handle, inode, path + depth);
3522                 if (err)
3523                         goto out;
3524                 ext4_ext_mark_initialized(ex);
3525                 ext4_ext_try_to_merge(handle, inode, path, ex);
3526                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3527                 goto out;
3528         }
3529
3530         /*
3531          * four cases:
3532          * 1. split the extent into three extents.
3533          * 2. split the extent into two extents, zeroout the first half.
3534          * 3. split the extent into two extents, zeroout the second half.
3535          * 4. split the extent into two extents with out zeroout.
3536          */
3537         split_map.m_lblk = map->m_lblk;
3538         split_map.m_len = map->m_len;
3539
3540         if (max_zeroout && (allocated > map->m_len)) {
3541                 if (allocated <= max_zeroout) {
3542                         /* case 3 */
3543                         zero_ex.ee_block =
3544                                          cpu_to_le32(map->m_lblk);
3545                         zero_ex.ee_len = cpu_to_le16(allocated);
3546                         ext4_ext_store_pblock(&zero_ex,
3547                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3548                         err = ext4_ext_zeroout(inode, &zero_ex);
3549                         if (err)
3550                                 goto out;
3551                         split_map.m_lblk = map->m_lblk;
3552                         split_map.m_len = allocated;
3553                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3554                         /* case 2 */
3555                         if (map->m_lblk != ee_block) {
3556                                 zero_ex.ee_block = ex->ee_block;
3557                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3558                                                         ee_block);
3559                                 ext4_ext_store_pblock(&zero_ex,
3560                                                       ext4_ext_pblock(ex));
3561                                 err = ext4_ext_zeroout(inode, &zero_ex);
3562                                 if (err)
3563                                         goto out;
3564                         }
3565
3566                         split_map.m_lblk = ee_block;
3567                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3568                         allocated = map->m_len;
3569                 }
3570         }
3571
3572         allocated = ext4_split_extent(handle, inode, path,
3573                                       &split_map, split_flag, flags);
3574         if (allocated < 0)
3575                 err = allocated;
3576
3577 out:
3578         /* If we have gotten a failure, don't zero out status tree */
3579         if (!err)
3580                 err = ext4_zeroout_es(inode, &zero_ex);
3581         return err ? err : allocated;
3582 }
3583
3584 /*
3585  * This function is called by ext4_ext_map_blocks() from
3586  * ext4_get_blocks_dio_write() when DIO to write
3587  * to an uninitialized extent.
3588  *
3589  * Writing to an uninitialized extent may result in splitting the uninitialized
3590  * extent into multiple initialized/uninitialized extents (up to three)
3591  * There are three possibilities:
3592  *   a> There is no split required: Entire extent should be uninitialized
3593  *   b> Splits in two extents: Write is happening at either end of the extent
3594  *   c> Splits in three extents: Somone is writing in middle of the extent
3595  *
3596  * One of more index blocks maybe needed if the extent tree grow after
3597  * the uninitialized extent split. To prevent ENOSPC occur at the IO
3598  * complete, we need to split the uninitialized extent before DIO submit
3599  * the IO. The uninitialized extent called at this time will be split
3600  * into three uninitialized extent(at most). After IO complete, the part
3601  * being filled will be convert to initialized by the end_io callback function
3602  * via ext4_convert_unwritten_extents().
3603  *
3604  * Returns the size of uninitialized extent to be written on success.
3605  */
3606 static int ext4_split_unwritten_extents(handle_t *handle,
3607                                         struct inode *inode,
3608                                         struct ext4_map_blocks *map,
3609                                         struct ext4_ext_path *path,
3610                                         int flags)
3611 {
3612         ext4_lblk_t eof_block;
3613         ext4_lblk_t ee_block;
3614         struct ext4_extent *ex;
3615         unsigned int ee_len;
3616         int split_flag = 0, depth;
3617
3618         ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
3619                 "block %llu, max_blocks %u\n", inode->i_ino,
3620                 (unsigned long long)map->m_lblk, map->m_len);
3621
3622         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3623                 inode->i_sb->s_blocksize_bits;
3624         if (eof_block < map->m_lblk + map->m_len)
3625                 eof_block = map->m_lblk + map->m_len;
3626         /*
3627          * It is safe to convert extent to initialized via explicit
3628          * zeroout only if extent is fully insde i_size or new_size.
3629          */
3630         depth = ext_depth(inode);
3631         ex = path[depth].p_ext;
3632         ee_block = le32_to_cpu(ex->ee_block);
3633         ee_len = ext4_ext_get_actual_len(ex);
3634
3635         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3636         split_flag |= EXT4_EXT_MARK_UNINIT2;
3637         if (flags & EXT4_GET_BLOCKS_CONVERT)
3638                 split_flag |= EXT4_EXT_DATA_VALID2;
3639         flags |= EXT4_GET_BLOCKS_PRE_IO;
3640         return ext4_split_extent(handle, inode, path, map, split_flag, flags);
3641 }
3642
3643 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3644                                                 struct inode *inode,
3645                                                 struct ext4_map_blocks *map,
3646                                                 struct ext4_ext_path *path)
3647 {
3648         struct ext4_extent *ex;
3649         ext4_lblk_t ee_block;
3650         unsigned int ee_len;
3651         int depth;
3652         int err = 0;
3653
3654         depth = ext_depth(inode);
3655         ex = path[depth].p_ext;
3656         ee_block = le32_to_cpu(ex->ee_block);
3657         ee_len = ext4_ext_get_actual_len(ex);
3658
3659         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3660                 "block %llu, max_blocks %u\n", inode->i_ino,
3661                   (unsigned long long)ee_block, ee_len);
3662
3663         /* If extent is larger than requested it is a clear sign that we still
3664          * have some extent state machine issues left. So extent_split is still
3665          * required.
3666          * TODO: Once all related issues will be fixed this situation should be
3667          * illegal.
3668          */
3669         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3670 #ifdef EXT4_DEBUG
3671                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3672                              " len %u; IO logical block %llu, len %u\n",
3673                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3674                              (unsigned long long)map->m_lblk, map->m_len);
3675 #endif
3676                 err = ext4_split_unwritten_extents(handle, inode, map, path,
3677                                                    EXT4_GET_BLOCKS_CONVERT);
3678                 if (err < 0)
3679                         goto out;
3680                 ext4_ext_drop_refs(path);
3681                 path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3682                 if (IS_ERR(path)) {
3683                         err = PTR_ERR(path);
3684                         goto out;
3685                 }
3686                 depth = ext_depth(inode);
3687                 ex = path[depth].p_ext;
3688         }
3689
3690         err = ext4_ext_get_access(handle, inode, path + depth);
3691         if (err)
3692                 goto out;
3693         /* first mark the extent as initialized */
3694         ext4_ext_mark_initialized(ex);
3695
3696         /* note: ext4_ext_correct_indexes() isn't needed here because
3697          * borders are not changed
3698          */
3699         ext4_ext_try_to_merge(handle, inode, path, ex);
3700
3701         /* Mark modified extent as dirty */
3702         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3703 out:
3704         ext4_ext_show_leaf(inode, path);
3705         return err;
3706 }
3707
3708 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3709                         sector_t block, int count)
3710 {
3711         int i;
3712         for (i = 0; i < count; i++)
3713                 unmap_underlying_metadata(bdev, block + i);
3714 }
3715
3716 /*
3717  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3718  */
3719 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3720                               ext4_lblk_t lblk,
3721                               struct ext4_ext_path *path,
3722                               unsigned int len)
3723 {
3724         int i, depth;
3725         struct ext4_extent_header *eh;
3726         struct ext4_extent *last_ex;
3727
3728         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3729                 return 0;
3730
3731         depth = ext_depth(inode);
3732         eh = path[depth].p_hdr;
3733
3734         /*
3735          * We're going to remove EOFBLOCKS_FL entirely in future so we
3736          * do not care for this case anymore. Simply remove the flag
3737          * if there are no extents.
3738          */
3739         if (unlikely(!eh->eh_entries))
3740                 goto out;
3741         last_ex = EXT_LAST_EXTENT(eh);
3742         /*
3743          * We should clear the EOFBLOCKS_FL flag if we are writing the
3744          * last block in the last extent in the file.  We test this by
3745          * first checking to see if the caller to
3746          * ext4_ext_get_blocks() was interested in the last block (or
3747          * a block beyond the last block) in the current extent.  If
3748          * this turns out to be false, we can bail out from this
3749          * function immediately.
3750          */
3751         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3752             ext4_ext_get_actual_len(last_ex))
3753                 return 0;
3754         /*
3755          * If the caller does appear to be planning to write at or
3756          * beyond the end of the current extent, we then test to see
3757          * if the current extent is the last extent in the file, by
3758          * checking to make sure it was reached via the rightmost node
3759          * at each level of the tree.
3760          */
3761         for (i = depth-1; i >= 0; i--)
3762                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3763                         return 0;
3764 out:
3765         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3766         return ext4_mark_inode_dirty(handle, inode);
3767 }
3768
3769 /**
3770  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3771  *
3772  * Return 1 if there is a delalloc block in the range, otherwise 0.
3773  */
3774 int ext4_find_delalloc_range(struct inode *inode,
3775                              ext4_lblk_t lblk_start,
3776                              ext4_lblk_t lblk_end)
3777 {
3778         struct extent_status es;
3779
3780         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3781         if (es.es_len == 0)
3782                 return 0; /* there is no delay extent in this tree */
3783         else if (es.es_lblk <= lblk_start &&
3784                  lblk_start < es.es_lblk + es.es_len)
3785                 return 1;
3786         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3787                 return 1;
3788         else
3789                 return 0;
3790 }
3791
3792 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3793 {
3794         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3795         ext4_lblk_t lblk_start, lblk_end;
3796         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3797         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3798
3799         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3800 }
3801
3802 /**
3803  * Determines how many complete clusters (out of those specified by the 'map')
3804  * are under delalloc and were reserved quota for.
3805  * This function is called when we are writing out the blocks that were
3806  * originally written with their allocation delayed, but then the space was
3807  * allocated using fallocate() before the delayed allocation could be resolved.
3808  * The cases to look for are:
3809  * ('=' indicated delayed allocated blocks
3810  *  '-' indicates non-delayed allocated blocks)
3811  * (a) partial clusters towards beginning and/or end outside of allocated range
3812  *     are not delalloc'ed.
3813  *      Ex:
3814  *      |----c---=|====c====|====c====|===-c----|
3815  *               |++++++ allocated ++++++|
3816  *      ==> 4 complete clusters in above example
3817  *
3818  * (b) partial cluster (outside of allocated range) towards either end is
3819  *     marked for delayed allocation. In this case, we will exclude that
3820  *     cluster.
3821  *      Ex:
3822  *      |----====c========|========c========|
3823  *           |++++++ allocated ++++++|
3824  *      ==> 1 complete clusters in above example
3825  *
3826  *      Ex:
3827  *      |================c================|
3828  *            |++++++ allocated ++++++|
3829  *      ==> 0 complete clusters in above example
3830  *
3831  * The ext4_da_update_reserve_space will be called only if we
3832  * determine here that there were some "entire" clusters that span
3833  * this 'allocated' range.
3834  * In the non-bigalloc case, this function will just end up returning num_blks
3835  * without ever calling ext4_find_delalloc_range.
3836  */
3837 static unsigned int
3838 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3839                            unsigned int num_blks)
3840 {
3841         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3842         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3843         ext4_lblk_t lblk_from, lblk_to, c_offset;
3844         unsigned int allocated_clusters = 0;
3845
3846         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3847         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3848
3849         /* max possible clusters for this allocation */
3850         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3851
3852         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3853
3854         /* Check towards left side */
3855         c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3856         if (c_offset) {
3857                 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3858                 lblk_to = lblk_from + c_offset - 1;
3859
3860                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3861                         allocated_clusters--;
3862         }
3863
3864         /* Now check towards right. */
3865         c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3866         if (allocated_clusters && c_offset) {
3867                 lblk_from = lblk_start + num_blks;
3868                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3869
3870                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3871                         allocated_clusters--;
3872         }
3873
3874         return allocated_clusters;
3875 }
3876
3877 static int
3878 ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
3879                         struct ext4_map_blocks *map,
3880                         struct ext4_ext_path *path, int flags,
3881                         unsigned int allocated, ext4_fsblk_t newblock)
3882 {
3883         int ret = 0;
3884         int err = 0;
3885         ext4_io_end_t *io = ext4_inode_aio(inode);
3886
3887         ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical "
3888                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
3889                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
3890                   flags, allocated);
3891         ext4_ext_show_leaf(inode, path);
3892
3893         /*
3894          * When writing into uninitialized space, we should not fail to
3895          * allocate metadata blocks for the new extent block if needed.
3896          */
3897         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3898
3899         trace_ext4_ext_handle_uninitialized_extents(inode, map, flags,
3900                                                     allocated, newblock);
3901
3902         /* get_block() before submit the IO, split the extent */
3903         if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3904                 ret = ext4_split_unwritten_extents(handle, inode, map,
3905                                                    path, flags);
3906                 if (ret <= 0)
3907                         goto out;
3908                 /*
3909                  * Flag the inode(non aio case) or end_io struct (aio case)
3910                  * that this IO needs to conversion to written when IO is
3911                  * completed
3912                  */
3913                 if (io)
3914                         ext4_set_io_unwritten_flag(inode, io);
3915                 else
3916                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3917                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3918                 if (ext4_should_dioread_nolock(inode))
3919                         map->m_flags |= EXT4_MAP_UNINIT;
3920                 goto out;
3921         }
3922         /* IO end_io complete, convert the filled extent to written */
3923         if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
3924                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
3925                                                         path);
3926                 if (ret >= 0) {
3927                         ext4_update_inode_fsync_trans(handle, inode, 1);
3928                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
3929                                                  path, map->m_len);
3930                 } else
3931                         err = ret;
3932                 map->m_flags |= EXT4_MAP_MAPPED;
3933                 map->m_pblk = newblock;
3934                 if (allocated > map->m_len)
3935                         allocated = map->m_len;
3936                 map->m_len = allocated;
3937                 goto out2;
3938         }
3939         /* buffered IO case */
3940         /*
3941          * repeat fallocate creation request
3942          * we already have an unwritten extent
3943          */
3944         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT) {
3945                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3946                 goto map_out;
3947         }
3948
3949         /* buffered READ or buffered write_begin() lookup */
3950         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3951                 /*
3952                  * We have blocks reserved already.  We
3953                  * return allocated blocks so that delalloc
3954                  * won't do block reservation for us.  But
3955                  * the buffer head will be unmapped so that
3956                  * a read from the block returns 0s.
3957                  */
3958                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3959                 goto out1;
3960         }
3961
3962         /* buffered write, writepage time, convert*/
3963         ret = ext4_ext_convert_to_initialized(handle, inode, map, path, flags);
3964         if (ret >= 0)
3965                 ext4_update_inode_fsync_trans(handle, inode, 1);
3966 out:
3967         if (ret <= 0) {
3968                 err = ret;
3969                 goto out2;
3970         } else
3971                 allocated = ret;
3972         map->m_flags |= EXT4_MAP_NEW;
3973         /*
3974          * if we allocated more blocks than requested
3975          * we need to make sure we unmap the extra block
3976          * allocated. The actual needed block will get
3977          * unmapped later when we find the buffer_head marked
3978          * new.
3979          */
3980         if (allocated > map->m_len) {
3981                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
3982                                         newblock + map->m_len,
3983                                         allocated - map->m_len);
3984                 allocated = map->m_len;
3985         }
3986         map->m_len = allocated;
3987
3988         /*
3989          * If we have done fallocate with the offset that is already
3990          * delayed allocated, we would have block reservation
3991          * and quota reservation done in the delayed write path.
3992          * But fallocate would have already updated quota and block
3993          * count for this offset. So cancel these reservation
3994          */
3995         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
3996                 unsigned int reserved_clusters;
3997                 reserved_clusters = get_reserved_cluster_alloc(inode,
3998                                 map->m_lblk, map->m_len);
3999                 if (reserved_clusters)
4000                         ext4_da_update_reserve_space(inode,
4001                                                      reserved_clusters,
4002                                                      0);
4003         }
4004
4005 map_out:
4006         map->m_flags |= EXT4_MAP_MAPPED;
4007         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4008                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4009                                          map->m_len);
4010                 if (err < 0)
4011                         goto out2;
4012         }
4013 out1:
4014         if (allocated > map->m_len)
4015                 allocated = map->m_len;
4016         ext4_ext_show_leaf(inode, path);
4017         map->m_pblk = newblock;
4018         map->m_len = allocated;
4019 out2:
4020         if (path) {
4021                 ext4_ext_drop_refs(path);
4022                 kfree(path);
4023         }
4024         return err ? err : allocated;
4025 }
4026
4027 /*
4028  * get_implied_cluster_alloc - check to see if the requested
4029  * allocation (in the map structure) overlaps with a cluster already
4030  * allocated in an extent.
4031  *      @sb     The filesystem superblock structure
4032  *      @map    The requested lblk->pblk mapping
4033  *      @ex     The extent structure which might contain an implied
4034  *                      cluster allocation
4035  *
4036  * This function is called by ext4_ext_map_blocks() after we failed to
4037  * find blocks that were already in the inode's extent tree.  Hence,
4038  * we know that the beginning of the requested region cannot overlap
4039  * the extent from the inode's extent tree.  There are three cases we
4040  * want to catch.  The first is this case:
4041  *
4042  *               |--- cluster # N--|
4043  *    |--- extent ---|  |---- requested region ---|
4044  *                      |==========|
4045  *
4046  * The second case that we need to test for is this one:
4047  *
4048  *   |--------- cluster # N ----------------|
4049  *         |--- requested region --|   |------- extent ----|
4050  *         |=======================|
4051  *
4052  * The third case is when the requested region lies between two extents
4053  * within the same cluster:
4054  *          |------------- cluster # N-------------|
4055  * |----- ex -----|                  |---- ex_right ----|
4056  *                  |------ requested region ------|
4057  *                  |================|
4058  *
4059  * In each of the above cases, we need to set the map->m_pblk and
4060  * map->m_len so it corresponds to the return the extent labelled as
4061  * "|====|" from cluster #N, since it is already in use for data in
4062  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4063  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4064  * as a new "allocated" block region.  Otherwise, we will return 0 and
4065  * ext4_ext_map_blocks() will then allocate one or more new clusters
4066  * by calling ext4_mb_new_blocks().
4067  */
4068 static int get_implied_cluster_alloc(struct super_block *sb,
4069                                      struct ext4_map_blocks *map,
4070                                      struct ext4_extent *ex,
4071                                      struct ext4_ext_path *path)
4072 {
4073         struct ext4_sb_info *sbi = EXT4_SB(sb);
4074         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4075         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4076         ext4_lblk_t rr_cluster_start;
4077         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4078         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4079         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4080
4081         /* The extent passed in that we are trying to match */
4082         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4083         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4084
4085         /* The requested region passed into ext4_map_blocks() */
4086         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4087
4088         if ((rr_cluster_start == ex_cluster_end) ||
4089             (rr_cluster_start == ex_cluster_start)) {
4090                 if (rr_cluster_start == ex_cluster_end)
4091                         ee_start += ee_len - 1;
4092                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4093                 map->m_len = min(map->m_len,
4094                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4095                 /*
4096                  * Check for and handle this case:
4097                  *
4098                  *   |--------- cluster # N-------------|
4099                  *                     |------- extent ----|
4100                  *         |--- requested region ---|
4101                  *         |===========|
4102                  */
4103
4104                 if (map->m_lblk < ee_block)
4105                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4106
4107                 /*
4108                  * Check for the case where there is already another allocated
4109                  * block to the right of 'ex' but before the end of the cluster.
4110                  *
4111                  *          |------------- cluster # N-------------|
4112                  * |----- ex -----|                  |---- ex_right ----|
4113                  *                  |------ requested region ------|
4114                  *                  |================|
4115                  */
4116                 if (map->m_lblk > ee_block) {
4117                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4118                         map->m_len = min(map->m_len, next - map->m_lblk);
4119                 }
4120
4121                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4122                 return 1;
4123         }
4124
4125         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4126         return 0;
4127 }
4128
4129
4130 /*
4131  * Block allocation/map/preallocation routine for extents based files
4132  *
4133  *
4134  * Need to be called with
4135  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4136  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4137  *
4138  * return > 0, number of of blocks already mapped/allocated
4139  *          if create == 0 and these are pre-allocated blocks
4140  *              buffer head is unmapped
4141  *          otherwise blocks are mapped
4142  *
4143  * return = 0, if plain look up failed (blocks have not been allocated)
4144  *          buffer head is unmapped
4145  *
4146  * return < 0, error case.
4147  */
4148 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4149                         struct ext4_map_blocks *map, int flags)
4150 {
4151         struct ext4_ext_path *path = NULL;
4152         struct ext4_extent newex, *ex, *ex2;
4153         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4154         ext4_fsblk_t newblock = 0;
4155         int free_on_err = 0, err = 0, depth, ret;
4156         unsigned int allocated = 0, offset = 0;
4157         unsigned int allocated_clusters = 0;
4158         struct ext4_allocation_request ar;
4159         ext4_io_end_t *io = ext4_inode_aio(inode);
4160         ext4_lblk_t cluster_offset;
4161         int set_unwritten = 0;
4162
4163         ext_debug("blocks %u/%u requested for inode %lu\n",
4164                   map->m_lblk, map->m_len, inode->i_ino);
4165         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4166
4167         /* find extent for this block */
4168         path = ext4_ext_find_extent(inode, map->m_lblk, NULL, 0);
4169         if (IS_ERR(path)) {
4170                 err = PTR_ERR(path);
4171                 path = NULL;
4172                 goto out2;
4173         }
4174
4175         depth = ext_depth(inode);
4176
4177         /*
4178          * consistent leaf must not be empty;
4179          * this situation is possible, though, _during_ tree modification;
4180          * this is why assert can't be put in ext4_ext_find_extent()
4181          */
4182         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4183                 EXT4_ERROR_INODE(inode, "bad extent address "
4184                                  "lblock: %lu, depth: %d pblock %lld",
4185                                  (unsigned long) map->m_lblk, depth,
4186                                  path[depth].p_block);
4187                 err = -EIO;
4188                 goto out2;
4189         }
4190
4191         ex = path[depth].p_ext;
4192         if (ex) {
4193                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4194                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4195                 unsigned short ee_len;
4196
4197                 /*
4198                  * Uninitialized extents are treated as holes, except that
4199                  * we split out initialized portions during a write.
4200                  */
4201                 ee_len = ext4_ext_get_actual_len(ex);
4202
4203                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4204
4205                 /* if found extent covers block, simply return it */
4206                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4207                         newblock = map->m_lblk - ee_block + ee_start;
4208                         /* number of remaining blocks in the extent */
4209                         allocated = ee_len - (map->m_lblk - ee_block);
4210                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4211                                   ee_block, ee_len, newblock);
4212
4213                         if (!ext4_ext_is_uninitialized(ex))
4214                                 goto out;
4215
4216                         ret = ext4_ext_handle_uninitialized_extents(
4217                                 handle, inode, map, path, flags,
4218                                 allocated, newblock);
4219                         if (ret < 0)
4220                                 err = ret;
4221                         else
4222                                 allocated = ret;
4223                         goto out3;
4224                 }
4225         }
4226
4227         if ((sbi->s_cluster_ratio > 1) &&
4228             ext4_find_delalloc_cluster(inode, map->m_lblk))
4229                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4230
4231         /*
4232          * requested block isn't allocated yet;
4233          * we couldn't try to create block if create flag is zero
4234          */
4235         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4236                 /*
4237                  * put just found gap into cache to speed up
4238                  * subsequent requests
4239                  */
4240                 if ((flags & EXT4_GET_BLOCKS_NO_PUT_HOLE) == 0)
4241                         ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
4242                 goto out2;
4243         }
4244
4245         /*
4246          * Okay, we need to do block allocation.
4247          */
4248         map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
4249         newex.ee_block = cpu_to_le32(map->m_lblk);
4250         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4251
4252         /*
4253          * If we are doing bigalloc, check to see if the extent returned
4254          * by ext4_ext_find_extent() implies a cluster we can use.
4255          */
4256         if (cluster_offset && ex &&
4257             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4258                 ar.len = allocated = map->m_len;
4259                 newblock = map->m_pblk;
4260                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4261                 goto got_allocated_blocks;
4262         }
4263
4264         /* find neighbour allocated blocks */
4265         ar.lleft = map->m_lblk;
4266         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4267         if (err)
4268                 goto out2;
4269         ar.lright = map->m_lblk;
4270         ex2 = NULL;
4271         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4272         if (err)
4273                 goto out2;
4274
4275         /* Check if the extent after searching to the right implies a
4276          * cluster we can use. */
4277         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4278             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4279                 ar.len = allocated = map->m_len;
4280                 newblock = map->m_pblk;
4281                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4282                 goto got_allocated_blocks;
4283         }
4284
4285         /*
4286          * See if request is beyond maximum number of blocks we can have in
4287          * a single extent. For an initialized extent this limit is
4288          * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
4289          * EXT_UNINIT_MAX_LEN.
4290          */
4291         if (map->m_len > EXT_INIT_MAX_LEN &&
4292             !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
4293                 map->m_len = EXT_INIT_MAX_LEN;
4294         else if (map->m_len > EXT_UNINIT_MAX_LEN &&
4295                  (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
4296                 map->m_len = EXT_UNINIT_MAX_LEN;
4297
4298         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4299         newex.ee_len = cpu_to_le16(map->m_len);
4300         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4301         if (err)
4302                 allocated = ext4_ext_get_actual_len(&newex);
4303         else
4304                 allocated = map->m_len;
4305
4306         /* allocate new block */
4307         ar.inode = inode;
4308         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4309         ar.logical = map->m_lblk;
4310         /*
4311          * We calculate the offset from the beginning of the cluster
4312          * for the logical block number, since when we allocate a
4313          * physical cluster, the physical block should start at the
4314          * same offset from the beginning of the cluster.  This is
4315          * needed so that future calls to get_implied_cluster_alloc()
4316          * work correctly.
4317          */
4318         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4319         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4320         ar.goal -= offset;
4321         ar.logical -= offset;
4322         if (S_ISREG(inode->i_mode))
4323                 ar.flags = EXT4_MB_HINT_DATA;
4324         else
4325                 /* disable in-core preallocation for non-regular files */
4326                 ar.flags = 0;
4327         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4328                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4329         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4330         if (!newblock)
4331                 goto out2;
4332         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4333                   ar.goal, newblock, allocated);
4334         free_on_err = 1;
4335         allocated_clusters = ar.len;
4336         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4337         if (ar.len > allocated)
4338                 ar.len = allocated;
4339
4340 got_allocated_blocks:
4341         /* try to insert new extent into found leaf and return */
4342         ext4_ext_store_pblock(&newex, newblock + offset);
4343         newex.ee_len = cpu_to_le16(ar.len);
4344         /* Mark uninitialized */
4345         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
4346                 ext4_ext_mark_uninitialized(&newex);
4347                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4348                 /*
4349                  * io_end structure was created for every IO write to an
4350                  * uninitialized extent. To avoid unnecessary conversion,
4351                  * here we flag the IO that really needs the conversion.
4352                  * For non asycn direct IO case, flag the inode state
4353                  * that we need to perform conversion when IO is done.
4354                  */
4355                 if ((flags & EXT4_GET_BLOCKS_PRE_IO))
4356                         set_unwritten = 1;
4357                 if (ext4_should_dioread_nolock(inode))
4358                         map->m_flags |= EXT4_MAP_UNINIT;
4359         }
4360
4361         err = 0;
4362         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4363                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4364                                          path, ar.len);
4365         if (!err)
4366                 err = ext4_ext_insert_extent(handle, inode, path,
4367                                              &newex, flags);
4368
4369         if (!err && set_unwritten) {
4370                 if (io)
4371                         ext4_set_io_unwritten_flag(inode, io);
4372                 else
4373                         ext4_set_inode_state(inode,
4374                                              EXT4_STATE_DIO_UNWRITTEN);
4375         }
4376
4377         if (err && free_on_err) {
4378                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4379                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4380                 /* free data blocks we just allocated */
4381                 /* not a good idea to call discard here directly,
4382                  * but otherwise we'd need to call it every free() */
4383                 ext4_discard_preallocations(inode);
4384                 ext4_free_blocks(handle, inode, NULL, newblock,
4385                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4386                 goto out2;
4387         }
4388
4389         /* previous routine could use block we allocated */
4390         newblock = ext4_ext_pblock(&newex);
4391         allocated = ext4_ext_get_actual_len(&newex);
4392         if (allocated > map->m_len)
4393                 allocated = map->m_len;
4394         map->m_flags |= EXT4_MAP_NEW;
4395
4396         /*
4397          * Update reserved blocks/metadata blocks after successful
4398          * block allocation which had been deferred till now.
4399          */
4400         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4401                 unsigned int reserved_clusters;
4402                 /*
4403                  * Check how many clusters we had reserved this allocated range
4404                  */
4405                 reserved_clusters = get_reserved_cluster_alloc(inode,
4406                                                 map->m_lblk, allocated);
4407                 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) {
4408                         if (reserved_clusters) {
4409                                 /*
4410                                  * We have clusters reserved for this range.
4411                                  * But since we are not doing actual allocation
4412                                  * and are simply using blocks from previously
4413                                  * allocated cluster, we should release the
4414                                  * reservation and not claim quota.
4415                                  */
4416                                 ext4_da_update_reserve_space(inode,
4417                                                 reserved_clusters, 0);
4418                         }
4419                 } else {
4420                         BUG_ON(allocated_clusters < reserved_clusters);
4421                         if (reserved_clusters < allocated_clusters) {
4422                                 struct ext4_inode_info *ei = EXT4_I(inode);
4423                                 int reservation = allocated_clusters -
4424                                                   reserved_clusters;
4425                                 /*
4426                                  * It seems we claimed few clusters outside of
4427                                  * the range of this allocation. We should give
4428                                  * it back to the reservation pool. This can
4429                                  * happen in the following case:
4430                                  *
4431                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4432                                  *   cluster has 4 blocks. Thus, the clusters
4433                                  *   are [0-3],[4-7],[8-11]...
4434                                  * * First comes delayed allocation write for
4435                                  *   logical blocks 10 & 11. Since there were no
4436                                  *   previous delayed allocated blocks in the
4437                                  *   range [8-11], we would reserve 1 cluster
4438                                  *   for this write.
4439                                  * * Next comes write for logical blocks 3 to 8.
4440                                  *   In this case, we will reserve 2 clusters
4441                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4442                                  *   that range has a delayed allocated blocks.
4443                                  *   Thus total reserved clusters now becomes 3.
4444                                  * * Now, during the delayed allocation writeout
4445                                  *   time, we will first write blocks [3-8] and
4446                                  *   allocate 3 clusters for writing these
4447                                  *   blocks. Also, we would claim all these
4448                                  *   three clusters above.
4449                                  * * Now when we come here to writeout the
4450                                  *   blocks [10-11], we would expect to claim
4451                                  *   the reservation of 1 cluster we had made
4452                                  *   (and we would claim it since there are no
4453                                  *   more delayed allocated blocks in the range
4454                                  *   [8-11]. But our reserved cluster count had
4455                                  *   already gone to 0.
4456                                  *
4457                                  *   Thus, at the step 4 above when we determine
4458                                  *   that there are still some unwritten delayed
4459                                  *   allocated blocks outside of our current
4460                                  *   block range, we should increment the
4461                                  *   reserved clusters count so that when the
4462                                  *   remaining blocks finally gets written, we
4463                                  *   could claim them.
4464                                  */
4465                                 dquot_reserve_block(inode,
4466                                                 EXT4_C2B(sbi, reservation));
4467                                 spin_lock(&ei->i_block_reservation_lock);
4468                                 ei->i_reserved_data_blocks += reservation;
4469                                 spin_unlock(&ei->i_block_reservation_lock);
4470                         }
4471                         /*
4472                          * We will claim quota for all newly allocated blocks.
4473                          * We're updating the reserved space *after* the
4474                          * correction above so we do not accidentally free
4475                          * all the metadata reservation because we might
4476                          * actually need it later on.
4477                          */
4478                         ext4_da_update_reserve_space(inode, allocated_clusters,
4479                                                         1);
4480                 }
4481         }
4482
4483         /*
4484          * Cache the extent and update transaction to commit on fdatasync only
4485          * when it is _not_ an uninitialized extent.
4486          */
4487         if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0)
4488                 ext4_update_inode_fsync_trans(handle, inode, 1);
4489         else
4490                 ext4_update_inode_fsync_trans(handle, inode, 0);
4491 out:
4492         if (allocated > map->m_len)
4493                 allocated = map->m_len;
4494         ext4_ext_show_leaf(inode, path);
4495         map->m_flags |= EXT4_MAP_MAPPED;
4496         map->m_pblk = newblock;
4497         map->m_len = allocated;
4498 out2:
4499         if (path) {
4500                 ext4_ext_drop_refs(path);
4501                 kfree(path);
4502         }
4503
4504 out3:
4505         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4506                                        err ? err : allocated);
4507         ext4_es_lru_add(inode);
4508         return err ? err : allocated;
4509 }
4510
4511 void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4512 {
4513         struct super_block *sb = inode->i_sb;
4514         ext4_lblk_t last_block;
4515         int err = 0;
4516
4517         /*
4518          * TODO: optimization is possible here.
4519          * Probably we need not scan at all,
4520          * because page truncation is enough.
4521          */
4522
4523         /* we have to know where to truncate from in crash case */
4524         EXT4_I(inode)->i_disksize = inode->i_size;
4525         ext4_mark_inode_dirty(handle, inode);
4526
4527         last_block = (inode->i_size + sb->s_blocksize - 1)
4528                         >> EXT4_BLOCK_SIZE_BITS(sb);
4529 retry:
4530         err = ext4_es_remove_extent(inode, last_block,
4531                                     EXT_MAX_BLOCKS - last_block);
4532         if (err == -ENOMEM) {
4533                 cond_resched();
4534                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4535                 goto retry;
4536         }
4537         if (err) {
4538                 ext4_std_error(inode->i_sb, err);
4539                 return;
4540         }
4541         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4542         ext4_std_error(inode->i_sb, err);
4543 }
4544
4545 static void ext4_falloc_update_inode(struct inode *inode,
4546                                 int mode, loff_t new_size, int update_ctime)
4547 {
4548         struct timespec now;
4549
4550         if (update_ctime) {
4551                 now = current_fs_time(inode->i_sb);
4552                 if (!timespec_equal(&inode->i_ctime, &now))
4553                         inode->i_ctime = now;
4554         }
4555         /*
4556          * Update only when preallocation was requested beyond
4557          * the file size.
4558          */
4559         if (!(mode & FALLOC_FL_KEEP_SIZE)) {
4560                 if (new_size > i_size_read(inode))
4561                         i_size_write(inode, new_size);
4562                 if (new_size > EXT4_I(inode)->i_disksize)
4563                         ext4_update_i_disksize(inode, new_size);
4564         } else {
4565                 /*
4566                  * Mark that we allocate beyond EOF so the subsequent truncate
4567                  * can proceed even if the new size is the same as i_size.
4568                  */
4569                 if (new_size > i_size_read(inode))
4570                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4571         }
4572
4573 }
4574
4575 /*
4576  * preallocate space for a file. This implements ext4's fallocate file
4577  * operation, which gets called from sys_fallocate system call.
4578  * For block-mapped files, posix_fallocate should fall back to the method
4579  * of writing zeroes to the required new blocks (the same behavior which is
4580  * expected for file systems which do not support fallocate() system call).
4581  */
4582 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4583 {
4584         struct inode *inode = file_inode(file);
4585         handle_t *handle;
4586         loff_t new_size;
4587         unsigned int max_blocks;
4588         int ret = 0;
4589         int ret2 = 0;
4590         int retries = 0;
4591         int flags;
4592         struct ext4_map_blocks map;
4593         unsigned int credits, blkbits = inode->i_blkbits;
4594
4595         /* Return error if mode is not supported */
4596         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
4597                 return -EOPNOTSUPP;
4598
4599         if (mode & FALLOC_FL_PUNCH_HOLE)
4600                 return ext4_punch_hole(inode, offset, len);
4601
4602         ret = ext4_convert_inline_data(inode);
4603         if (ret)
4604                 return ret;
4605
4606         /*
4607          * currently supporting (pre)allocate mode for extent-based
4608          * files _only_
4609          */
4610         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4611                 return -EOPNOTSUPP;
4612
4613         trace_ext4_fallocate_enter(inode, offset, len, mode);
4614         map.m_lblk = offset >> blkbits;
4615         /*
4616          * We can't just convert len to max_blocks because
4617          * If blocksize = 4096 offset = 3072 and len = 2048
4618          */
4619         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4620                 - map.m_lblk;
4621         /*
4622          * credits to insert 1 extent into extent tree
4623          */
4624         credits = ext4_chunk_trans_blocks(inode, max_blocks);
4625         mutex_lock(&inode->i_mutex);
4626         ret = inode_newsize_ok(inode, (len + offset));
4627         if (ret) {
4628                 mutex_unlock(&inode->i_mutex);
4629                 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4630                 return ret;
4631         }
4632         flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT;
4633         if (mode & FALLOC_FL_KEEP_SIZE)
4634                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4635         /*
4636          * Don't normalize the request if it can fit in one extent so
4637          * that it doesn't get unnecessarily split into multiple
4638          * extents.
4639          */
4640         if (len <= EXT_UNINIT_MAX_LEN << blkbits)
4641                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4642
4643 retry:
4644         while (ret >= 0 && ret < max_blocks) {
4645                 map.m_lblk = map.m_lblk + ret;
4646                 map.m_len = max_blocks = max_blocks - ret;
4647                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4648                                             credits);
4649                 if (IS_ERR(handle)) {
4650                         ret = PTR_ERR(handle);
4651                         break;
4652                 }
4653                 ret = ext4_map_blocks(handle, inode, &map, flags);
4654                 if (ret <= 0) {
4655 #ifdef EXT4FS_DEBUG
4656                         ext4_warning(inode->i_sb,
4657                                      "inode #%lu: block %u: len %u: "
4658                                      "ext4_ext_map_blocks returned %d",
4659                                      inode->i_ino, map.m_lblk,
4660                                      map.m_len, ret);
4661 #endif
4662                         ext4_mark_inode_dirty(handle, inode);
4663                         ret2 = ext4_journal_stop(handle);
4664                         break;
4665                 }
4666                 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
4667                                                 blkbits) >> blkbits))
4668                         new_size = offset + len;
4669                 else
4670                         new_size = ((loff_t) map.m_lblk + ret) << blkbits;
4671
4672                 ext4_falloc_update_inode(inode, mode, new_size,
4673                                          (map.m_flags & EXT4_MAP_NEW));
4674                 ext4_mark_inode_dirty(handle, inode);
4675                 if ((file->f_flags & O_SYNC) && ret >= max_blocks)
4676                         ext4_handle_sync(handle);
4677                 ret2 = ext4_journal_stop(handle);
4678                 if (ret2)
4679                         break;
4680         }
4681         if (ret == -ENOSPC &&
4682                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4683                 ret = 0;
4684                 goto retry;
4685         }
4686         mutex_unlock(&inode->i_mutex);
4687         trace_ext4_fallocate_exit(inode, offset, max_blocks,
4688                                 ret > 0 ? ret2 : ret);
4689         return ret > 0 ? ret2 : ret;
4690 }
4691
4692 /*
4693  * This function convert a range of blocks to written extents
4694  * The caller of this function will pass the start offset and the size.
4695  * all unwritten extents within this range will be converted to
4696  * written extents.
4697  *
4698  * This function is called from the direct IO end io call back
4699  * function, to convert the fallocated extents after IO is completed.
4700  * Returns 0 on success.
4701  */
4702 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4703                                    loff_t offset, ssize_t len)
4704 {
4705         unsigned int max_blocks;
4706         int ret = 0;
4707         int ret2 = 0;
4708         struct ext4_map_blocks map;
4709         unsigned int credits, blkbits = inode->i_blkbits;
4710
4711         map.m_lblk = offset >> blkbits;
4712         /*
4713          * We can't just convert len to max_blocks because
4714          * If blocksize = 4096 offset = 3072 and len = 2048
4715          */
4716         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
4717                       map.m_lblk);
4718         /*
4719          * This is somewhat ugly but the idea is clear: When transaction is
4720          * reserved, everything goes into it. Otherwise we rather start several
4721          * smaller transactions for conversion of each extent separately.
4722          */
4723         if (handle) {
4724                 handle = ext4_journal_start_reserved(handle,
4725                                                      EXT4_HT_EXT_CONVERT);
4726                 if (IS_ERR(handle))
4727                         return PTR_ERR(handle);
4728                 credits = 0;
4729         } else {
4730                 /*
4731                  * credits to insert 1 extent into extent tree
4732                  */
4733                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4734         }
4735         while (ret >= 0 && ret < max_blocks) {
4736                 map.m_lblk += ret;
4737                 map.m_len = (max_blocks -= ret);
4738                 if (credits) {
4739                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4740                                                     credits);
4741                         if (IS_ERR(handle)) {
4742                                 ret = PTR_ERR(handle);
4743                                 break;
4744                         }
4745                 }
4746                 ret = ext4_map_blocks(handle, inode, &map,
4747                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4748                 if (ret <= 0)
4749                         ext4_warning(inode->i_sb,
4750                                      "inode #%lu: block %u: len %u: "
4751                                      "ext4_ext_map_blocks returned %d",
4752                                      inode->i_ino, map.m_lblk,
4753                                      map.m_len, ret);
4754                 ext4_mark_inode_dirty(handle, inode);
4755                 if (credits)
4756                         ret2 = ext4_journal_stop(handle);
4757                 if (ret <= 0 || ret2)
4758                         break;
4759         }
4760         if (!credits)
4761                 ret2 = ext4_journal_stop(handle);
4762         return ret > 0 ? ret2 : ret;
4763 }
4764
4765 /*
4766  * If newes is not existing extent (newes->ec_pblk equals zero) find
4767  * delayed extent at start of newes and update newes accordingly and
4768  * return start of the next delayed extent.
4769  *
4770  * If newes is existing extent (newes->ec_pblk is not equal zero)
4771  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
4772  * extent found. Leave newes unmodified.
4773  */
4774 static int ext4_find_delayed_extent(struct inode *inode,
4775                                     struct extent_status *newes)
4776 {
4777         struct extent_status es;
4778         ext4_lblk_t block, next_del;
4779
4780         if (newes->es_pblk == 0) {
4781                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
4782                                 newes->es_lblk + newes->es_len - 1, &es);
4783
4784                 /*
4785                  * No extent in extent-tree contains block @newes->es_pblk,
4786                  * then the block may stay in 1)a hole or 2)delayed-extent.
4787                  */
4788                 if (es.es_len == 0)
4789                         /* A hole found. */
4790                         return 0;
4791
4792                 if (es.es_lblk > newes->es_lblk) {
4793                         /* A hole found. */
4794                         newes->es_len = min(es.es_lblk - newes->es_lblk,
4795                                             newes->es_len);
4796                         return 0;
4797                 }
4798
4799                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
4800         }
4801
4802         block = newes->es_lblk + newes->es_len;
4803         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
4804         if (es.es_len == 0)
4805                 next_del = EXT_MAX_BLOCKS;
4806         else
4807                 next_del = es.es_lblk;
4808
4809         return next_del;
4810 }
4811 /* fiemap flags we can handle specified here */
4812 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
4813
4814 static int ext4_xattr_fiemap(struct inode *inode,
4815                                 struct fiemap_extent_info *fieinfo)
4816 {
4817         __u64 physical = 0;
4818         __u64 length;
4819         __u32 flags = FIEMAP_EXTENT_LAST;
4820         int blockbits = inode->i_sb->s_blocksize_bits;
4821         int error = 0;
4822
4823         /* in-inode? */
4824         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4825                 struct ext4_iloc iloc;
4826                 int offset;     /* offset of xattr in inode */
4827
4828                 error = ext4_get_inode_loc(inode, &iloc);
4829                 if (error)
4830                         return error;
4831                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
4832                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4833                                 EXT4_I(inode)->i_extra_isize;
4834                 physical += offset;
4835                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4836                 flags |= FIEMAP_EXTENT_DATA_INLINE;
4837                 brelse(iloc.bh);
4838         } else { /* external block */
4839                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4840                 length = inode->i_sb->s_blocksize;
4841         }
4842
4843         if (physical)
4844                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
4845                                                 length, flags);
4846         return (error < 0 ? error : 0);
4847 }
4848
4849 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4850                 __u64 start, __u64 len)
4851 {
4852         ext4_lblk_t start_blk;
4853         int error = 0;
4854
4855         if (ext4_has_inline_data(inode)) {
4856                 int has_inline = 1;
4857
4858                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline);
4859
4860                 if (has_inline)
4861                         return error;
4862         }
4863
4864         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4865                 error = ext4_ext_precache(inode);
4866                 if (error)
4867                         return error;
4868         }
4869
4870         /* fallback to generic here if not in extents fmt */
4871         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4872                 return generic_block_fiemap(inode, fieinfo, start, len,
4873                         ext4_get_block);
4874
4875         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
4876                 return -EBADR;
4877
4878         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4879                 error = ext4_xattr_fiemap(inode, fieinfo);
4880         } else {
4881                 ext4_lblk_t len_blks;
4882                 __u64 last_blk;
4883
4884                 start_blk = start >> inode->i_sb->s_blocksize_bits;
4885                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
4886                 if (last_blk >= EXT_MAX_BLOCKS)
4887                         last_blk = EXT_MAX_BLOCKS-1;
4888                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
4889
4890                 /*
4891                  * Walk the extent tree gathering extent information
4892                  * and pushing extents back to the user.
4893                  */
4894                 error = ext4_fill_fiemap_extents(inode, start_blk,
4895                                                  len_blks, fieinfo);
4896         }
4897         ext4_es_lru_add(inode);
4898         return error;
4899 }