fs/ext4/extents.c

   1 /*
   2  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3  * Written by Alex Tomas <alex@clusterfs.com>
   4  *
   5  * Architecture independence:
   6  *   Copyright (c) 2005, Bull S.A.
   7  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public Licens
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21  */
  22
  23 /*
  24  * Extents support for EXT4
  25  *
  26  * TODO:
  27  *   - ext4*_error() should be used in some situations
  28  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29  *   - smart tree reduction
  30  */
  31
  32 #include <linux/fs.h>
  33 #include <linux/time.h>
  34 #include <linux/jbd2.h>
  35 #include <linux/highuid.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/quotaops.h>
  38 #include <linux/string.h>
  39 #include <linux/slab.h>
  40 #include <asm/uaccess.h>
  41 #include <linux/fiemap.h>
  42 #include "ext4_jbd2.h"
  43 #include "ext4_extents.h"
  44 #include "xattr.h"
  45
  46 #include <trace/events/ext4.h>
  47
  48 /*
  49  * used by extent splitting.
  50  */
  51 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  52                                         due to ENOSPC */
  53 #define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  54 #define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  55
  56 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  57 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  58
  59 static __le32 ext4_extent_block_csum(struct inode *inode,
  60                                      struct ext4_extent_header *eh)
  61 {
  62         struct ext4_inode_info *ei = EXT4_I(inode);
  63         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  64         __u32 csum;
  65
  66         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  67                            EXT4_EXTENT_TAIL_OFFSET(eh));
  68         return cpu_to_le32(csum);
  69 }
  70
  71 static int ext4_extent_block_csum_verify(struct inode *inode,
  72                                          struct ext4_extent_header *eh)
  73 {
  74         struct ext4_extent_tail *et;
  75
  76         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  77                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  78                 return 1;
  79
  80         et = find_ext4_extent_tail(eh);
  81         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  82                 return 0;
  83         return 1;
  84 }
  85
  86 static void ext4_extent_block_csum_set(struct inode *inode,
  87                                        struct ext4_extent_header *eh)
  88 {
  89         struct ext4_extent_tail *et;
  90
  91         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  92                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  93                 return;
  94
  95         et = find_ext4_extent_tail(eh);
  96         et->et_checksum = ext4_extent_block_csum(inode, eh);
  97 }
  98
  99 static int ext4_split_extent(handle_t *handle,
 100                                 struct inode *inode,
 101                                 struct ext4_ext_path **ppath,
 102                                 struct ext4_map_blocks *map,
 103                                 int split_flag,
 104                                 int flags);
 105
 106 static int ext4_split_extent_at(handle_t *handle,
 107                              struct inode *inode,
 108                              struct ext4_ext_path **ppath,
 109                              ext4_lblk_t split,
 110                              int split_flag,
 111                              int flags);
 112
 113 static int ext4_find_delayed_extent(struct inode *inode,
 114                                     struct extent_status *newes);
 115
 116 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 117                                             struct inode *inode,
 118                                             int needed)
 119 {
 120         int err;
 121
 122         if (!ext4_handle_valid(handle))
 123                 return 0;
 124         if (handle->h_buffer_credits > needed)
 125                 return 0;
 126         err = ext4_journal_extend(handle, needed);
 127         if (err <= 0)
 128                 return err;
 129         err = ext4_truncate_restart_trans(handle, inode, needed);
 130         if (err == 0)
 131                 err = -EAGAIN;
 132
 133         return err;
 134 }
 135
 136 /*
 137  * could return:
 138  *  - EROFS
 139  *  - ENOMEM
 140  */
 141 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 142                                 struct ext4_ext_path *path)
 143 {
 144         if (path->p_bh) {
 145                 /* path points to block */
 146                 BUFFER_TRACE(path->p_bh, "get_write_access");
 147                 return ext4_journal_get_write_access(handle, path->p_bh);
 148         }
 149         /* path points to leaf/index in inode body */
 150         /* we use in-core data, no need to protect them */
 151         return 0;
 152 }
 153
 154 /*
 155  * could return:
 156  *  - EROFS
 157  *  - ENOMEM
 158  *  - EIO
 159  */
 160 int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 161                      struct inode *inode, struct ext4_ext_path *path)
 162 {
 163         int err;
 164
 165         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 166         if (path->p_bh) {
 167                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 168                 /* path points to block */
 169                 err = __ext4_handle_dirty_metadata(where, line, handle,
 170                                                    inode, path->p_bh);
 171         } else {
 172                 /* path points to leaf/index in inode body */
 173                 err = ext4_mark_inode_dirty(handle, inode);
 174         }
 175         return err;
 176 }
 177
 178 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 179                               struct ext4_ext_path *path,
 180                               ext4_lblk_t block)
 181 {
 182         if (path) {
 183                 int depth = path->p_depth;
 184                 struct ext4_extent *ex;
 185
 186                 /*
 187                  * Try to predict block placement assuming that we are
 188                  * filling in a file which will eventually be
 189                  * non-sparse --- i.e., in the case of libbfd writing
 190                  * an ELF object sections out-of-order but in a way
 191                  * the eventually results in a contiguous object or
 192                  * executable file, or some database extending a table
 193                  * space file.  However, this is actually somewhat
 194                  * non-ideal if we are writing a sparse file such as
 195                  * qemu or KVM writing a raw image file that is going
 196                  * to stay fairly sparse, since it will end up
 197                  * fragmenting the file system's free space.  Maybe we
 198                  * should have some hueristics or some way to allow
 199                  * userspace to pass a hint to file system,
 200                  * especially if the latter case turns out to be
 201                  * common.
 202                  */
 203                 ex = path[depth].p_ext;
 204                 if (ex) {
 205                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 206                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 207
 208                         if (block > ext_block)
 209                                 return ext_pblk + (block - ext_block);
 210                         else
 211                                 return ext_pblk - (ext_block - block);
 212                 }
 213
 214                 /* it looks like index is empty;
 215                  * try to find starting block from index itself */
 216                 if (path[depth].p_bh)
 217                         return path[depth].p_bh->b_blocknr;
 218         }
 219
 220         /* OK. use inode's group */
 221         return ext4_inode_to_goal_block(inode);
 222 }
 223
 224 /*
 225  * Allocation for a meta data block
 226  */
 227 static ext4_fsblk_t
 228 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 229                         struct ext4_ext_path *path,
 230                         struct ext4_extent *ex, int *err, unsigned int flags)
 231 {
 232         ext4_fsblk_t goal, newblock;
 233
 234         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 235         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 236                                         NULL, err);
 237         return newblock;
 238 }
 239
 240 static inline int ext4_ext_space_block(struct inode *inode, int check)
 241 {
 242         int size;
 243
 244         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 245                         / sizeof(struct ext4_extent);
 246 #ifdef AGGRESSIVE_TEST
 247         if (!check && size > 6)
 248                 size = 6;
 249 #endif
 250         return size;
 251 }
 252
 253 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 254 {
 255         int size;
 256
 257         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 258                         / sizeof(struct ext4_extent_idx);
 259 #ifdef AGGRESSIVE_TEST
 260         if (!check && size > 5)
 261                 size = 5;
 262 #endif
 263         return size;
 264 }
 265
 266 static inline int ext4_ext_space_root(struct inode *inode, int check)
 267 {
 268         int size;
 269
 270         size = sizeof(EXT4_I(inode)->i_data);
 271         size -= sizeof(struct ext4_extent_header);
 272         size /= sizeof(struct ext4_extent);
 273 #ifdef AGGRESSIVE_TEST
 274         if (!check && size > 3)
 275                 size = 3;
 276 #endif
 277         return size;
 278 }
 279
 280 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 281 {
 282         int size;
 283
 284         size = sizeof(EXT4_I(inode)->i_data);
 285         size -= sizeof(struct ext4_extent_header);
 286         size /= sizeof(struct ext4_extent_idx);
 287 #ifdef AGGRESSIVE_TEST
 288         if (!check && size > 4)
 289                 size = 4;
 290 #endif
 291         return size;
 292 }
 293
 294 static inline int
 295 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 296                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 297                            int nofail)
 298 {
 299         struct ext4_ext_path *path = *ppath;
 300         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 301
 302         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 303                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 304                         EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
 305                         (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
 306 }
 307
 308 /*
 309  * Calculate the number of metadata blocks needed
 310  * to allocate @blocks
 311  * Worse case is one block per extent
 312  */
 313 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 314 {
 315         struct ext4_inode_info *ei = EXT4_I(inode);
 316         int idxs;
 317
 318         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 319                 / sizeof(struct ext4_extent_idx));
 320
 321         /*
 322          * If the new delayed allocation block is contiguous with the
 323          * previous da block, it can share index blocks with the
 324          * previous block, so we only need to allocate a new index
 325          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 326          * an additional index block, and at ldxs**3 blocks, yet
 327          * another index blocks.
 328          */
 329         if (ei->i_da_metadata_calc_len &&
 330             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 331                 int num = 0;
 332
 333                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 334                         num++;
 335                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 336                         num++;
 337                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 338                         num++;
 339                         ei->i_da_metadata_calc_len = 0;
 340                 } else
 341                         ei->i_da_metadata_calc_len++;
 342                 ei->i_da_metadata_calc_last_lblock++;
 343                 return num;
 344         }
 345
 346         /*
 347          * In the worst case we need a new set of index blocks at
 348          * every level of the inode's extent tree.
 349          */
 350         ei->i_da_metadata_calc_len = 1;
 351         ei->i_da_metadata_calc_last_lblock = lblock;
 352         return ext_depth(inode) + 1;
 353 }
 354
 355 static int
 356 ext4_ext_max_entries(struct inode *inode, int depth)
 357 {
 358         int max;
 359
 360         if (depth == ext_depth(inode)) {
 361                 if (depth == 0)
 362                         max = ext4_ext_space_root(inode, 1);
 363                 else
 364                         max = ext4_ext_space_root_idx(inode, 1);
 365         } else {
 366                 if (depth == 0)
 367                         max = ext4_ext_space_block(inode, 1);
 368                 else
 369                         max = ext4_ext_space_block_idx(inode, 1);
 370         }
 371
 372         return max;
 373 }
 374
 375 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 376 {
 377         ext4_fsblk_t block = ext4_ext_pblock(ext);
 378         int len = ext4_ext_get_actual_len(ext);
 379         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 380         ext4_lblk_t last = lblock + len - 1;
 381
 382         if (lblock > last)
 383                 return 0;
 384         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 385 }
 386
 387 static int ext4_valid_extent_idx(struct inode *inode,
 388                                 struct ext4_extent_idx *ext_idx)
 389 {
 390         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 391
 392         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 393 }
 394
 395 static int ext4_valid_extent_entries(struct inode *inode,
 396                                 struct ext4_extent_header *eh,
 397                                 int depth)
 398 {
 399         unsigned short entries;
 400         if (eh->eh_entries == 0)
 401                 return 1;
 402
 403         entries = le16_to_cpu(eh->eh_entries);
 404
 405         if (depth == 0) {
 406                 /* leaf entries */
 407                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 408                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 409                 ext4_fsblk_t pblock = 0;
 410                 ext4_lblk_t lblock = 0;
 411                 ext4_lblk_t prev = 0;
 412                 int len = 0;
 413                 while (entries) {
 414                         if (!ext4_valid_extent(inode, ext))
 415                                 return 0;
 416
 417                         /* Check for overlapping extents */
 418                         lblock = le32_to_cpu(ext->ee_block);
 419                         len = ext4_ext_get_actual_len(ext);
 420                         if ((lblock <= prev) && prev) {
 421                                 pblock = ext4_ext_pblock(ext);
 422                                 es->s_last_error_block = cpu_to_le64(pblock);
 423                                 return 0;
 424                         }
 425                         ext++;
 426                         entries--;
 427                         prev = lblock + len - 1;
 428                 }
 429         } else {
 430                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 431                 while (entries) {
 432                         if (!ext4_valid_extent_idx(inode, ext_idx))
 433                                 return 0;
 434                         ext_idx++;
 435                         entries--;
 436                 }
 437         }
 438         return 1;
 439 }
 440
 441 static int __ext4_ext_check(const char *function, unsigned int line,
 442                             struct inode *inode, struct ext4_extent_header *eh,
 443                             int depth, ext4_fsblk_t pblk)
 444 {
 445         const char *error_msg;
 446         int max = 0;
 447
 448         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 449                 error_msg = "invalid magic";
 450                 goto corrupted;
 451         }
 452         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 453                 error_msg = "unexpected eh_depth";
 454                 goto corrupted;
 455         }
 456         if (unlikely(eh->eh_max == 0)) {
 457                 error_msg = "invalid eh_max";
 458                 goto corrupted;
 459         }
 460         max = ext4_ext_max_entries(inode, depth);
 461         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 462                 error_msg = "too large eh_max";
 463                 goto corrupted;
 464         }
 465         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 466                 error_msg = "invalid eh_entries";
 467                 goto corrupted;
 468         }
 469         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 470                 error_msg = "invalid extent entries";
 471                 goto corrupted;
 472         }
 473         /* Verify checksum on non-root extent tree nodes */
 474         if (ext_depth(inode) != depth &&
 475             !ext4_extent_block_csum_verify(inode, eh)) {
 476                 error_msg = "extent tree corrupted";
 477                 goto corrupted;
 478         }
 479         return 0;
 480
 481 corrupted:
 482         ext4_error_inode(inode, function, line, 0,
 483                          "pblk %llu bad header/extent: %s - magic %x, "
 484                          "entries %u, max %u(%u), depth %u(%u)",
 485                          (unsigned long long) pblk, error_msg,
 486                          le16_to_cpu(eh->eh_magic),
 487                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 488                          max, le16_to_cpu(eh->eh_depth), depth);
 489         return -EIO;
 490 }
 491
 492 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 493         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 494
 495 int ext4_ext_check_inode(struct inode *inode)
 496 {
 497         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 498 }
 499
 500 static struct buffer_head *
 501 __read_extent_tree_block(const char *function, unsigned int line,
 502                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 503                          int flags)
 504 {
 505         struct buffer_head              *bh;
 506         int                             err;
 507
 508         bh = sb_getblk(inode->i_sb, pblk);
 509         if (unlikely(!bh))
 510                 return ERR_PTR(-ENOMEM);
 511
 512         if (!bh_uptodate_or_lock(bh)) {
 513                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 514                 err = bh_submit_read(bh);
 515                 if (err < 0)
 516                         goto errout;
 517         }
 518         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 519                 return bh;
 520         err = __ext4_ext_check(function, line, inode,
 521                                ext_block_hdr(bh), depth, pblk);
 522         if (err)
 523                 goto errout;
 524         set_buffer_verified(bh);
 525         /*
 526          * If this is a leaf block, cache all of its entries
 527          */
 528         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 529                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 530                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 531                 ext4_lblk_t prev = 0;
 532                 int i;
 533
 534                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 535                         unsigned int status = EXTENT_STATUS_WRITTEN;
 536                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 537                         int len = ext4_ext_get_actual_len(ex);
 538
 539                         if (prev && (prev != lblk))
 540                                 ext4_es_cache_extent(inode, prev,
 541                                                      lblk - prev, ~0,
 542                                                      EXTENT_STATUS_HOLE);
 543
 544                         if (ext4_ext_is_unwritten(ex))
 545                                 status = EXTENT_STATUS_UNWRITTEN;
 546                         ext4_es_cache_extent(inode, lblk, len,
 547                                              ext4_ext_pblock(ex), status);
 548                         prev = lblk + len;
 549                 }
 550         }
 551         return bh;
 552 errout:
 553         put_bh(bh);
 554         return ERR_PTR(err);
 555
 556 }
 557
 558 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 559         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 560                                  (depth), (flags))
 561
 562 /*
 563  * This function is called to cache a file's extent information in the
 564  * extent status tree
 565  */
 566 int ext4_ext_precache(struct inode *inode)
 567 {
 568         struct ext4_inode_info *ei = EXT4_I(inode);
 569         struct ext4_ext_path *path = NULL;
 570         struct buffer_head *bh;
 571         int i = 0, depth, ret = 0;
 572
 573         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 574                 return 0;       /* not an extent-mapped inode */
 575
 576         down_read(&ei->i_data_sem);
 577         depth = ext_depth(inode);
 578
 579         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 580                        GFP_NOFS);
 581         if (path == NULL) {
 582                 up_read(&ei->i_data_sem);
 583                 return -ENOMEM;
 584         }
 585
 586         /* Don't cache anything if there are no external extent blocks */
 587         if (depth == 0)
 588                 goto out;
 589         path[0].p_hdr = ext_inode_hdr(inode);
 590         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 591         if (ret)
 592                 goto out;
 593         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 594         while (i >= 0) {
 595                 /*
 596                  * If this is a leaf block or we've reached the end of
 597                  * the index block, go up
 598                  */
 599                 if ((i == depth) ||
 600                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 601                         brelse(path[i].p_bh);
 602                         path[i].p_bh = NULL;
 603                         i--;
 604                         continue;
 605                 }
 606                 bh = read_extent_tree_block(inode,
 607                                             ext4_idx_pblock(path[i].p_idx++),
 608                                             depth - i - 1,
 609                                             EXT4_EX_FORCE_CACHE);
 610                 if (IS_ERR(bh)) {
 611                         ret = PTR_ERR(bh);
 612                         break;
 613                 }
 614                 i++;
 615                 path[i].p_bh = bh;
 616                 path[i].p_hdr = ext_block_hdr(bh);
 617                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 618         }
 619         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 620 out:
 621         up_read(&ei->i_data_sem);
 622         ext4_ext_drop_refs(path);
 623         kfree(path);
 624         return ret;
 625 }
 626
 627 #ifdef EXT_DEBUG
 628 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 629 {
 630         int k, l = path->p_depth;
 631
 632         ext_debug("path:");
 633         for (k = 0; k <= l; k++, path++) {
 634                 if (path->p_idx) {
 635                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 636                             ext4_idx_pblock(path->p_idx));
 637                 } else if (path->p_ext) {
 638                         ext_debug("  %d:[%d]%d:%llu ",
 639                                   le32_to_cpu(path->p_ext->ee_block),
 640                                   ext4_ext_is_unwritten(path->p_ext),
 641                                   ext4_ext_get_actual_len(path->p_ext),
 642                                   ext4_ext_pblock(path->p_ext));
 643                 } else
 644                         ext_debug("  []");
 645         }
 646         ext_debug("\n");
 647 }
 648
 649 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 650 {
 651         int depth = ext_depth(inode);
 652         struct ext4_extent_header *eh;
 653         struct ext4_extent *ex;
 654         int i;
 655
 656         if (!path)
 657                 return;
 658
 659         eh = path[depth].p_hdr;
 660         ex = EXT_FIRST_EXTENT(eh);
 661
 662         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 663
 664         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 665                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 666                           ext4_ext_is_unwritten(ex),
 667                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 668         }
 669         ext_debug("\n");
 670 }
 671
 672 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 673                         ext4_fsblk_t newblock, int level)
 674 {
 675         int depth = ext_depth(inode);
 676         struct ext4_extent *ex;
 677
 678         if (depth != level) {
 679                 struct ext4_extent_idx *idx;
 680                 idx = path[level].p_idx;
 681                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 682                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 683                                         le32_to_cpu(idx->ei_block),
 684                                         ext4_idx_pblock(idx),
 685                                         newblock);
 686                         idx++;
 687                 }
 688
 689                 return;
 690         }
 691
 692         ex = path[depth].p_ext;
 693         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 694                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 695                                 le32_to_cpu(ex->ee_block),
 696                                 ext4_ext_pblock(ex),
 697                                 ext4_ext_is_unwritten(ex),
 698                                 ext4_ext_get_actual_len(ex),
 699                                 newblock);
 700                 ex++;
 701         }
 702 }
 703
 704 #else
 705 #define ext4_ext_show_path(inode, path)
 706 #define ext4_ext_show_leaf(inode, path)
 707 #define ext4_ext_show_move(inode, path, newblock, level)
 708 #endif
 709
 710 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 711 {
 712         int depth, i;
 713
 714         if (!path)
 715                 return;
 716         depth = path->p_depth;
 717         for (i = 0; i <= depth; i++, path++)
 718                 if (path->p_bh) {
 719                         brelse(path->p_bh);
 720                         path->p_bh = NULL;
 721                 }
 722 }
 723
 724 /*
 725  * ext4_ext_binsearch_idx:
 726  * binary search for the closest index of the given block
 727  * the header must be checked before calling this
 728  */
 729 static void
 730 ext4_ext_binsearch_idx(struct inode *inode,
 731                         struct ext4_ext_path *path, ext4_lblk_t block)
 732 {
 733         struct ext4_extent_header *eh = path->p_hdr;
 734         struct ext4_extent_idx *r, *l, *m;
 735
 736
 737         ext_debug("binsearch for %u(idx):  ", block);
 738
 739         l = EXT_FIRST_INDEX(eh) + 1;
 740         r = EXT_LAST_INDEX(eh);
 741         while (l <= r) {
 742                 m = l + (r - l) / 2;
 743                 if (block < le32_to_cpu(m->ei_block))
 744                         r = m - 1;
 745                 else
 746                         l = m + 1;
 747                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 748                                 m, le32_to_cpu(m->ei_block),
 749                                 r, le32_to_cpu(r->ei_block));
 750         }
 751
 752         path->p_idx = l - 1;
 753         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 754                   ext4_idx_pblock(path->p_idx));
 755
 756 #ifdef CHECK_BINSEARCH
 757         {
 758                 struct ext4_extent_idx *chix, *ix;
 759                 int k;
 760
 761                 chix = ix = EXT_FIRST_INDEX(eh);
 762                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 763                   if (k != 0 &&
 764                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 765                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 766                                        "first=0x%p\n", k,
 767                                        ix, EXT_FIRST_INDEX(eh));
 768                                 printk(KERN_DEBUG "%u <= %u\n",
 769                                        le32_to_cpu(ix->ei_block),
 770                                        le32_to_cpu(ix[-1].ei_block));
 771                         }
 772                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 773                                            <= le32_to_cpu(ix[-1].ei_block));
 774                         if (block < le32_to_cpu(ix->ei_block))
 775                                 break;
 776                         chix = ix;
 777                 }
 778                 BUG_ON(chix != path->p_idx);
 779         }
 780 #endif
 781
 782 }
 783
 784 /*
 785  * ext4_ext_binsearch:
 786  * binary search for closest extent of the given block
 787  * the header must be checked before calling this
 788  */
 789 static void
 790 ext4_ext_binsearch(struct inode *inode,
 791                 struct ext4_ext_path *path, ext4_lblk_t block)
 792 {
 793         struct ext4_extent_header *eh = path->p_hdr;
 794         struct ext4_extent *r, *l, *m;
 795
 796         if (eh->eh_entries == 0) {
 797                 /*
 798                  * this leaf is empty:
 799                  * we get such a leaf in split/add case
 800                  */
 801                 return;
 802         }
 803
 804         ext_debug("binsearch for %u:  ", block);
 805
 806         l = EXT_FIRST_EXTENT(eh) + 1;
 807         r = EXT_LAST_EXTENT(eh);
 808
 809         while (l <= r) {
 810                 m = l + (r - l) / 2;
 811                 if (block < le32_to_cpu(m->ee_block))
 812                         r = m - 1;
 813                 else
 814                         l = m + 1;
 815                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 816                                 m, le32_to_cpu(m->ee_block),
 817                                 r, le32_to_cpu(r->ee_block));
 818         }
 819
 820         path->p_ext = l - 1;
 821         ext_debug("  -> %d:%llu:[%d]%d ",
 822                         le32_to_cpu(path->p_ext->ee_block),
 823                         ext4_ext_pblock(path->p_ext),
 824                         ext4_ext_is_unwritten(path->p_ext),
 825                         ext4_ext_get_actual_len(path->p_ext));
 826
 827 #ifdef CHECK_BINSEARCH
 828         {
 829                 struct ext4_extent *chex, *ex;
 830                 int k;
 831
 832                 chex = ex = EXT_FIRST_EXTENT(eh);
 833                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 834                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 835                                           <= le32_to_cpu(ex[-1].ee_block));
 836                         if (block < le32_to_cpu(ex->ee_block))
 837                                 break;
 838                         chex = ex;
 839                 }
 840                 BUG_ON(chex != path->p_ext);
 841         }
 842 #endif
 843
 844 }
 845
 846 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 847 {
 848         struct ext4_extent_header *eh;
 849
 850         eh = ext_inode_hdr(inode);
 851         eh->eh_depth = 0;
 852         eh->eh_entries = 0;
 853         eh->eh_magic = EXT4_EXT_MAGIC;
 854         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 855         ext4_mark_inode_dirty(handle, inode);
 856         return 0;
 857 }
 858
 859 struct ext4_ext_path *
 860 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 861                  struct ext4_ext_path **orig_path, int flags)
 862 {
 863         struct ext4_extent_header *eh;
 864         struct buffer_head *bh;
 865         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 866         short int depth, i, ppos = 0;
 867         int ret;
 868
 869         eh = ext_inode_hdr(inode);
 870         depth = ext_depth(inode);
 871
 872         if (path) {
 873                 ext4_ext_drop_refs(path);
 874                 if (depth > path[0].p_maxdepth) {
 875                         kfree(path);
 876                         *orig_path = path = NULL;
 877                 }
 878         }
 879         if (!path) {
 880                 /* account possible depth increase */
 881                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 882                                 GFP_NOFS);
 883                 if (unlikely(!path))
 884                         return ERR_PTR(-ENOMEM);
 885                 path[0].p_maxdepth = depth + 1;
 886         }
 887         path[0].p_hdr = eh;
 888         path[0].p_bh = NULL;
 889
 890         i = depth;
 891         /* walk through the tree */
 892         while (i) {
 893                 ext_debug("depth %d: num %d, max %d\n",
 894                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 895
 896                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 897                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 898                 path[ppos].p_depth = i;
 899                 path[ppos].p_ext = NULL;
 900
 901                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 902                                             flags);
 903                 if (unlikely(IS_ERR(bh))) {
 904                         ret = PTR_ERR(bh);
 905                         goto err;
 906                 }
 907
 908                 eh = ext_block_hdr(bh);
 909                 ppos++;
 910                 if (unlikely(ppos > depth)) {
 911                         put_bh(bh);
 912                         EXT4_ERROR_INODE(inode,
 913                                          "ppos %d > depth %d", ppos, depth);
 914                         ret = -EIO;
 915                         goto err;
 916                 }
 917                 path[ppos].p_bh = bh;
 918                 path[ppos].p_hdr = eh;
 919         }
 920
 921         path[ppos].p_depth = i;
 922         path[ppos].p_ext = NULL;
 923         path[ppos].p_idx = NULL;
 924
 925         /* find extent */
 926         ext4_ext_binsearch(inode, path + ppos, block);
 927         /* if not an empty leaf */
 928         if (path[ppos].p_ext)
 929                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 930
 931         ext4_ext_show_path(inode, path);
 932
 933         return path;
 934
 935 err:
 936         ext4_ext_drop_refs(path);
 937         kfree(path);
 938         if (orig_path)
 939                 *orig_path = NULL;
 940         return ERR_PTR(ret);
 941 }
 942
 943 /*
 944  * ext4_ext_insert_index:
 945  * insert new index [@logical;@ptr] into the block at @curp;
 946  * check where to insert: before @curp or after @curp
 947  */
 948 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 949                                  struct ext4_ext_path *curp,
 950                                  int logical, ext4_fsblk_t ptr)
 951 {
 952         struct ext4_extent_idx *ix;
 953         int len, err;
 954
 955         err = ext4_ext_get_access(handle, inode, curp);
 956         if (err)
 957                 return err;
 958
 959         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 960                 EXT4_ERROR_INODE(inode,
 961                                  "logical %d == ei_block %d!",
 962                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 963                 return -EIO;
 964         }
 965
 966         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 967                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 968                 EXT4_ERROR_INODE(inode,
 969                                  "eh_entries %d >= eh_max %d!",
 970                                  le16_to_cpu(curp->p_hdr->eh_entries),
 971                                  le16_to_cpu(curp->p_hdr->eh_max));
 972                 return -EIO;
 973         }
 974
 975         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 976                 /* insert after */
 977                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 978                 ix = curp->p_idx + 1;
 979         } else {
 980                 /* insert before */
 981                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 982                 ix = curp->p_idx;
 983         }
 984
 985         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 986         BUG_ON(len < 0);
 987         if (len > 0) {
 988                 ext_debug("insert new index %d: "
 989                                 "move %d indices from 0x%p to 0x%p\n",
 990                                 logical, len, ix, ix + 1);
 991                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 992         }
 993
 994         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 995                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 996                 return -EIO;
 997         }
 998
 999         ix->ei_block = cpu_to_le32(logical);
1000         ext4_idx_store_pblock(ix, ptr);
1001         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1002
1003         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1004                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1005                 return -EIO;
1006         }
1007
1008         err = ext4_ext_dirty(handle, inode, curp);
1009         ext4_std_error(inode->i_sb, err);
1010
1011         return err;
1012 }
1013
1014 /*
1015  * ext4_ext_split:
1016  * inserts new subtree into the path, using free index entry
1017  * at depth @at:
1018  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1019  * - makes decision where to split
1020  * - moves remaining extents and index entries (right to the split point)
1021  *   into the newly allocated blocks
1022  * - initializes subtree
1023  */
1024 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1025                           unsigned int flags,
1026                           struct ext4_ext_path *path,
1027                           struct ext4_extent *newext, int at)
1028 {
1029         struct buffer_head *bh = NULL;
1030         int depth = ext_depth(inode);
1031         struct ext4_extent_header *neh;
1032         struct ext4_extent_idx *fidx;
1033         int i = at, k, m, a;
1034         ext4_fsblk_t newblock, oldblock;
1035         __le32 border;
1036         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1037         int err = 0;
1038
1039         /* make decision: where to split? */
1040         /* FIXME: now decision is simplest: at current extent */
1041
1042         /* if current leaf will be split, then we should use
1043          * border from split point */
1044         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1045                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1046                 return -EIO;
1047         }
1048         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1049                 border = path[depth].p_ext[1].ee_block;
1050                 ext_debug("leaf will be split."
1051                                 " next leaf starts at %d\n",
1052                                   le32_to_cpu(border));
1053         } else {
1054                 border = newext->ee_block;
1055                 ext_debug("leaf will be added."
1056                                 " next leaf starts at %d\n",
1057                                 le32_to_cpu(border));
1058         }
1059
1060         /*
1061          * If error occurs, then we break processing
1062          * and mark filesystem read-only. index won't
1063          * be inserted and tree will be in consistent
1064          * state. Next mount will repair buffers too.
1065          */
1066
1067         /*
1068          * Get array to track all allocated blocks.
1069          * We need this to handle errors and free blocks
1070          * upon them.
1071          */
1072         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1073         if (!ablocks)
1074                 return -ENOMEM;
1075
1076         /* allocate all needed blocks */
1077         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1078         for (a = 0; a < depth - at; a++) {
1079                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1080                                                    newext, &err, flags);
1081                 if (newblock == 0)
1082                         goto cleanup;
1083                 ablocks[a] = newblock;
1084         }
1085
1086         /* initialize new leaf */
1087         newblock = ablocks[--a];
1088         if (unlikely(newblock == 0)) {
1089                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1090                 err = -EIO;
1091                 goto cleanup;
1092         }
1093         bh = sb_getblk(inode->i_sb, newblock);
1094         if (unlikely(!bh)) {
1095                 err = -ENOMEM;
1096                 goto cleanup;
1097         }
1098         lock_buffer(bh);
1099
1100         err = ext4_journal_get_create_access(handle, bh);
1101         if (err)
1102                 goto cleanup;
1103
1104         neh = ext_block_hdr(bh);
1105         neh->eh_entries = 0;
1106         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1107         neh->eh_magic = EXT4_EXT_MAGIC;
1108         neh->eh_depth = 0;
1109
1110         /* move remainder of path[depth] to the new leaf */
1111         if (unlikely(path[depth].p_hdr->eh_entries !=
1112                      path[depth].p_hdr->eh_max)) {
1113                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1114                                  path[depth].p_hdr->eh_entries,
1115                                  path[depth].p_hdr->eh_max);
1116                 err = -EIO;
1117                 goto cleanup;
1118         }
1119         /* start copy from next extent */
1120         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1121         ext4_ext_show_move(inode, path, newblock, depth);
1122         if (m) {
1123                 struct ext4_extent *ex;
1124                 ex = EXT_FIRST_EXTENT(neh);
1125                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1126                 le16_add_cpu(&neh->eh_entries, m);
1127         }
1128
1129         ext4_extent_block_csum_set(inode, neh);
1130         set_buffer_uptodate(bh);
1131         unlock_buffer(bh);
1132
1133         err = ext4_handle_dirty_metadata(handle, inode, bh);
1134         if (err)
1135                 goto cleanup;
1136         brelse(bh);
1137         bh = NULL;
1138
1139         /* correct old leaf */
1140         if (m) {
1141                 err = ext4_ext_get_access(handle, inode, path + depth);
1142                 if (err)
1143                         goto cleanup;
1144                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1145                 err = ext4_ext_dirty(handle, inode, path + depth);
1146                 if (err)
1147                         goto cleanup;
1148
1149         }
1150
1151         /* create intermediate indexes */
1152         k = depth - at - 1;
1153         if (unlikely(k < 0)) {
1154                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1155                 err = -EIO;
1156                 goto cleanup;
1157         }
1158         if (k)
1159                 ext_debug("create %d intermediate indices\n", k);
1160         /* insert new index into current index block */
1161         /* current depth stored in i var */
1162         i = depth - 1;
1163         while (k--) {
1164                 oldblock = newblock;
1165                 newblock = ablocks[--a];
1166                 bh = sb_getblk(inode->i_sb, newblock);
1167                 if (unlikely(!bh)) {
1168                         err = -ENOMEM;
1169                         goto cleanup;
1170                 }
1171                 lock_buffer(bh);
1172
1173                 err = ext4_journal_get_create_access(handle, bh);
1174                 if (err)
1175                         goto cleanup;
1176
1177                 neh = ext_block_hdr(bh);
1178                 neh->eh_entries = cpu_to_le16(1);
1179                 neh->eh_magic = EXT4_EXT_MAGIC;
1180                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1181                 neh->eh_depth = cpu_to_le16(depth - i);
1182                 fidx = EXT_FIRST_INDEX(neh);
1183                 fidx->ei_block = border;
1184                 ext4_idx_store_pblock(fidx, oldblock);
1185
1186                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1187                                 i, newblock, le32_to_cpu(border), oldblock);
1188
1189                 /* move remainder of path[i] to the new index block */
1190                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1191                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1192                         EXT4_ERROR_INODE(inode,
1193                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1194                                          le32_to_cpu(path[i].p_ext->ee_block));
1195                         err = -EIO;
1196                         goto cleanup;
1197                 }
1198                 /* start copy indexes */
1199                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1200                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1201                                 EXT_MAX_INDEX(path[i].p_hdr));
1202                 ext4_ext_show_move(inode, path, newblock, i);
1203                 if (m) {
1204                         memmove(++fidx, path[i].p_idx,
1205                                 sizeof(struct ext4_extent_idx) * m);
1206                         le16_add_cpu(&neh->eh_entries, m);
1207                 }
1208                 ext4_extent_block_csum_set(inode, neh);
1209                 set_buffer_uptodate(bh);
1210                 unlock_buffer(bh);
1211
1212                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1213                 if (err)
1214                         goto cleanup;
1215                 brelse(bh);
1216                 bh = NULL;
1217
1218                 /* correct old index */
1219                 if (m) {
1220                         err = ext4_ext_get_access(handle, inode, path + i);
1221                         if (err)
1222                                 goto cleanup;
1223                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1224                         err = ext4_ext_dirty(handle, inode, path + i);
1225                         if (err)
1226                                 goto cleanup;
1227                 }
1228
1229                 i--;
1230         }
1231
1232         /* insert new index */
1233         err = ext4_ext_insert_index(handle, inode, path + at,
1234                                     le32_to_cpu(border), newblock);
1235
1236 cleanup:
1237         if (bh) {
1238                 if (buffer_locked(bh))
1239                         unlock_buffer(bh);
1240                 brelse(bh);
1241         }
1242
1243         if (err) {
1244                 /* free all allocated blocks in error case */
1245                 for (i = 0; i < depth; i++) {
1246                         if (!ablocks[i])
1247                                 continue;
1248                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1249                                          EXT4_FREE_BLOCKS_METADATA);
1250                 }
1251         }
1252         kfree(ablocks);
1253
1254         return err;
1255 }
1256
1257 /*
1258  * ext4_ext_grow_indepth:
1259  * implements tree growing procedure:
1260  * - allocates new block
1261  * - moves top-level data (index block or leaf) into the new block
1262  * - initializes new top-level, creating index that points to the
1263  *   just created block
1264  */
1265 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1266                                  unsigned int flags)
1267 {
1268         struct ext4_extent_header *neh;
1269         struct buffer_head *bh;
1270         ext4_fsblk_t newblock, goal = 0;
1271         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1272         int err = 0;
1273
1274         /* Try to prepend new index to old one */
1275         if (ext_depth(inode))
1276                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1277         if (goal > le32_to_cpu(es->s_first_data_block)) {
1278                 flags |= EXT4_MB_HINT_TRY_GOAL;
1279                 goal--;
1280         } else
1281                 goal = ext4_inode_to_goal_block(inode);
1282         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1283                                         NULL, &err);
1284         if (newblock == 0)
1285                 return err;
1286
1287         bh = sb_getblk(inode->i_sb, newblock);
1288         if (unlikely(!bh))
1289                 return -ENOMEM;
1290         lock_buffer(bh);
1291
1292         err = ext4_journal_get_create_access(handle, bh);
1293         if (err) {
1294                 unlock_buffer(bh);
1295                 goto out;
1296         }
1297
1298         /* move top-level index/leaf into new block */
1299         memmove(bh->b_data, EXT4_I(inode)->i_data,
1300                 sizeof(EXT4_I(inode)->i_data));
1301
1302         /* set size of new block */
1303         neh = ext_block_hdr(bh);
1304         /* old root could have indexes or leaves
1305          * so calculate e_max right way */
1306         if (ext_depth(inode))
1307                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1308         else
1309                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1310         neh->eh_magic = EXT4_EXT_MAGIC;
1311         ext4_extent_block_csum_set(inode, neh);
1312         set_buffer_uptodate(bh);
1313         unlock_buffer(bh);
1314
1315         err = ext4_handle_dirty_metadata(handle, inode, bh);
1316         if (err)
1317                 goto out;
1318
1319         /* Update top-level index: num,max,pointer */
1320         neh = ext_inode_hdr(inode);
1321         neh->eh_entries = cpu_to_le16(1);
1322         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1323         if (neh->eh_depth == 0) {
1324                 /* Root extent block becomes index block */
1325                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1326                 EXT_FIRST_INDEX(neh)->ei_block =
1327                         EXT_FIRST_EXTENT(neh)->ee_block;
1328         }
1329         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1330                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1331                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1332                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1333
1334         le16_add_cpu(&neh->eh_depth, 1);
1335         ext4_mark_inode_dirty(handle, inode);
1336 out:
1337         brelse(bh);
1338
1339         return err;
1340 }
1341
1342 /*
1343  * ext4_ext_create_new_leaf:
1344  * finds empty index and adds new leaf.
1345  * if no free index is found, then it requests in-depth growing.
1346  */
1347 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1348                                     unsigned int mb_flags,
1349                                     unsigned int gb_flags,
1350                                     struct ext4_ext_path **ppath,
1351                                     struct ext4_extent *newext)
1352 {
1353         struct ext4_ext_path *path = *ppath;
1354         struct ext4_ext_path *curp;
1355         int depth, i, err = 0;
1356
1357 repeat:
1358         i = depth = ext_depth(inode);
1359
1360         /* walk up to the tree and look for free index entry */
1361         curp = path + depth;
1362         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1363                 i--;
1364                 curp--;
1365         }
1366
1367         /* we use already allocated block for index block,
1368          * so subsequent data blocks should be contiguous */
1369         if (EXT_HAS_FREE_INDEX(curp)) {
1370                 /* if we found index with free entry, then use that
1371                  * entry: create all needed subtree and add new leaf */
1372                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1373                 if (err)
1374                         goto out;
1375
1376                 /* refill path */
1377                 path = ext4_find_extent(inode,
1378                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1379                                     ppath, gb_flags);
1380                 if (IS_ERR(path))
1381                         err = PTR_ERR(path);
1382         } else {
1383                 /* tree is full, time to grow in depth */
1384                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1385                 if (err)
1386                         goto out;
1387
1388                 /* refill path */
1389                 path = ext4_find_extent(inode,
1390                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1391                                     ppath, gb_flags);
1392                 if (IS_ERR(path)) {
1393                         err = PTR_ERR(path);
1394                         goto out;
1395                 }
1396
1397                 /*
1398                  * only first (depth 0 -> 1) produces free space;
1399                  * in all other cases we have to split the grown tree
1400                  */
1401                 depth = ext_depth(inode);
1402                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1403                         /* now we need to split */
1404                         goto repeat;
1405                 }
1406         }
1407
1408 out:
1409         return err;
1410 }
1411
1412 /*
1413  * search the closest allocated block to the left for *logical
1414  * and returns it at @logical + it's physical address at @phys
1415  * if *logical is the smallest allocated block, the function
1416  * returns 0 at @phys
1417  * return value contains 0 (success) or error code
1418  */
1419 static int ext4_ext_search_left(struct inode *inode,
1420                                 struct ext4_ext_path *path,
1421                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1422 {
1423         struct ext4_extent_idx *ix;
1424         struct ext4_extent *ex;
1425         int depth, ee_len;
1426
1427         if (unlikely(path == NULL)) {
1428                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1429                 return -EIO;
1430         }
1431         depth = path->p_depth;
1432         *phys = 0;
1433
1434         if (depth == 0 && path->p_ext == NULL)
1435                 return 0;
1436
1437         /* usually extent in the path covers blocks smaller
1438          * then *logical, but it can be that extent is the
1439          * first one in the file */
1440
1441         ex = path[depth].p_ext;
1442         ee_len = ext4_ext_get_actual_len(ex);
1443         if (*logical < le32_to_cpu(ex->ee_block)) {
1444                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1445                         EXT4_ERROR_INODE(inode,
1446                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1447                                          *logical, le32_to_cpu(ex->ee_block));
1448                         return -EIO;
1449                 }
1450                 while (--depth >= 0) {
1451                         ix = path[depth].p_idx;
1452                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1453                                 EXT4_ERROR_INODE(inode,
1454                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1455                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1456                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1457                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1458                                   depth);
1459                                 return -EIO;
1460                         }
1461                 }
1462                 return 0;
1463         }
1464
1465         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1466                 EXT4_ERROR_INODE(inode,
1467                                  "logical %d < ee_block %d + ee_len %d!",
1468                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1469                 return -EIO;
1470         }
1471
1472         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1473         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1474         return 0;
1475 }
1476
1477 /*
1478  * search the closest allocated block to the right for *logical
1479  * and returns it at @logical + it's physical address at @phys
1480  * if *logical is the largest allocated block, the function
1481  * returns 0 at @phys
1482  * return value contains 0 (success) or error code
1483  */
1484 static int ext4_ext_search_right(struct inode *inode,
1485                                  struct ext4_ext_path *path,
1486                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1487                                  struct ext4_extent **ret_ex)
1488 {
1489         struct buffer_head *bh = NULL;
1490         struct ext4_extent_header *eh;
1491         struct ext4_extent_idx *ix;
1492         struct ext4_extent *ex;
1493         ext4_fsblk_t block;
1494         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1495         int ee_len;
1496
1497         if (unlikely(path == NULL)) {
1498                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1499                 return -EIO;
1500         }
1501         depth = path->p_depth;
1502         *phys = 0;
1503
1504         if (depth == 0 && path->p_ext == NULL)
1505                 return 0;
1506
1507         /* usually extent in the path covers blocks smaller
1508          * then *logical, but it can be that extent is the
1509          * first one in the file */
1510
1511         ex = path[depth].p_ext;
1512         ee_len = ext4_ext_get_actual_len(ex);
1513         if (*logical < le32_to_cpu(ex->ee_block)) {
1514                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1515                         EXT4_ERROR_INODE(inode,
1516                                          "first_extent(path[%d].p_hdr) != ex",
1517                                          depth);
1518                         return -EIO;
1519                 }
1520                 while (--depth >= 0) {
1521                         ix = path[depth].p_idx;
1522                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1523                                 EXT4_ERROR_INODE(inode,
1524                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1525                                                  *logical);
1526                                 return -EIO;
1527                         }
1528                 }
1529                 goto found_extent;
1530         }
1531
1532         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1533                 EXT4_ERROR_INODE(inode,
1534                                  "logical %d < ee_block %d + ee_len %d!",
1535                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1536                 return -EIO;
1537         }
1538
1539         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1540                 /* next allocated block in this leaf */
1541                 ex++;
1542                 goto found_extent;
1543         }
1544
1545         /* go up and search for index to the right */
1546         while (--depth >= 0) {
1547                 ix = path[depth].p_idx;
1548                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1549                         goto got_index;
1550         }
1551
1552         /* we've gone up to the root and found no index to the right */
1553         return 0;
1554
1555 got_index:
1556         /* we've found index to the right, let's
1557          * follow it and find the closest allocated
1558          * block to the right */
1559         ix++;
1560         block = ext4_idx_pblock(ix);
1561         while (++depth < path->p_depth) {
1562                 /* subtract from p_depth to get proper eh_depth */
1563                 bh = read_extent_tree_block(inode, block,
1564                                             path->p_depth - depth, 0);
1565                 if (IS_ERR(bh))
1566                         return PTR_ERR(bh);
1567                 eh = ext_block_hdr(bh);
1568                 ix = EXT_FIRST_INDEX(eh);
1569                 block = ext4_idx_pblock(ix);
1570                 put_bh(bh);
1571         }
1572
1573         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1574         if (IS_ERR(bh))
1575                 return PTR_ERR(bh);
1576         eh = ext_block_hdr(bh);
1577         ex = EXT_FIRST_EXTENT(eh);
1578 found_extent:
1579         *logical = le32_to_cpu(ex->ee_block);
1580         *phys = ext4_ext_pblock(ex);
1581         *ret_ex = ex;
1582         if (bh)
1583                 put_bh(bh);
1584         return 0;
1585 }
1586
1587 /*
1588  * ext4_ext_next_allocated_block:
1589  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1590  * NOTE: it considers block number from index entry as
1591  * allocated block. Thus, index entries have to be consistent
1592  * with leaves.
1593  */
1594 ext4_lblk_t
1595 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1596 {
1597         int depth;
1598
1599         BUG_ON(path == NULL);
1600         depth = path->p_depth;
1601
1602         if (depth == 0 && path->p_ext == NULL)
1603                 return EXT_MAX_BLOCKS;
1604
1605         while (depth >= 0) {
1606                 if (depth == path->p_depth) {
1607                         /* leaf */
1608                         if (path[depth].p_ext &&
1609                                 path[depth].p_ext !=
1610                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1611                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1612                 } else {
1613                         /* index */
1614                         if (path[depth].p_idx !=
1615                                         EXT_LAST_INDEX(path[depth].p_hdr))
1616                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1617                 }
1618                 depth--;
1619         }
1620
1621         return EXT_MAX_BLOCKS;
1622 }
1623
1624 /*
1625  * ext4_ext_next_leaf_block:
1626  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1627  */
1628 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1629 {
1630         int depth;
1631
1632         BUG_ON(path == NULL);
1633         depth = path->p_depth;
1634
1635         /* zero-tree has no leaf blocks at all */
1636         if (depth == 0)
1637                 return EXT_MAX_BLOCKS;
1638
1639         /* go to index block */
1640         depth--;
1641
1642         while (depth >= 0) {
1643                 if (path[depth].p_idx !=
1644                                 EXT_LAST_INDEX(path[depth].p_hdr))
1645                         return (ext4_lblk_t)
1646                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1647                 depth--;
1648         }
1649
1650         return EXT_MAX_BLOCKS;
1651 }
1652
1653 /*
1654  * ext4_ext_correct_indexes:
1655  * if leaf gets modified and modified extent is first in the leaf,
1656  * then we have to correct all indexes above.
1657  * TODO: do we need to correct tree in all cases?
1658  */
1659 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1660                                 struct ext4_ext_path *path)
1661 {
1662         struct ext4_extent_header *eh;
1663         int depth = ext_depth(inode);
1664         struct ext4_extent *ex;
1665         __le32 border;
1666         int k, err = 0;
1667
1668         eh = path[depth].p_hdr;
1669         ex = path[depth].p_ext;
1670
1671         if (unlikely(ex == NULL || eh == NULL)) {
1672                 EXT4_ERROR_INODE(inode,
1673                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1674                 return -EIO;
1675         }
1676
1677         if (depth == 0) {
1678                 /* there is no tree at all */
1679                 return 0;
1680         }
1681
1682         if (ex != EXT_FIRST_EXTENT(eh)) {
1683                 /* we correct tree if first leaf got modified only */
1684                 return 0;
1685         }
1686
1687         /*
1688          * TODO: we need correction if border is smaller than current one
1689          */
1690         k = depth - 1;
1691         border = path[depth].p_ext->ee_block;
1692         err = ext4_ext_get_access(handle, inode, path + k);
1693         if (err)
1694                 return err;
1695         path[k].p_idx->ei_block = border;
1696         err = ext4_ext_dirty(handle, inode, path + k);
1697         if (err)
1698                 return err;
1699
1700         while (k--) {
1701                 /* change all left-side indexes */
1702                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1703                         break;
1704                 err = ext4_ext_get_access(handle, inode, path + k);
1705                 if (err)
1706                         break;
1707                 path[k].p_idx->ei_block = border;
1708                 err = ext4_ext_dirty(handle, inode, path + k);
1709                 if (err)
1710                         break;
1711         }
1712
1713         return err;
1714 }
1715
1716 int
1717 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1718                                 struct ext4_extent *ex2)
1719 {
1720         unsigned short ext1_ee_len, ext2_ee_len;
1721
1722         /*
1723          * Make sure that both extents are initialized. We don't merge
1724          * unwritten extents so that we can be sure that end_io code has
1725          * the extent that was written properly split out and conversion to
1726          * initialized is trivial.
1727          */
1728         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1729                 return 0;
1730
1731         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1732         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1733
1734         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1735                         le32_to_cpu(ex2->ee_block))
1736                 return 0;
1737
1738         /*
1739          * To allow future support for preallocated extents to be added
1740          * as an RO_COMPAT feature, refuse to merge to extents if
1741          * this can result in the top bit of ee_len being set.
1742          */
1743         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1744                 return 0;
1745         if (ext4_ext_is_unwritten(ex1) &&
1746             (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1747              atomic_read(&EXT4_I(inode)->i_unwritten) ||
1748              (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1749                 return 0;
1750 #ifdef AGGRESSIVE_TEST
1751         if (ext1_ee_len >= 4)
1752                 return 0;
1753 #endif
1754
1755         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1756                 return 1;
1757         return 0;
1758 }
1759
1760 /*
1761  * This function tries to merge the "ex" extent to the next extent in the tree.
1762  * It always tries to merge towards right. If you want to merge towards
1763  * left, pass "ex - 1" as argument instead of "ex".
1764  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1765  * 1 if they got merged.
1766  */
1767 static int ext4_ext_try_to_merge_right(struct inode *inode,
1768                                  struct ext4_ext_path *path,
1769                                  struct ext4_extent *ex)
1770 {
1771         struct ext4_extent_header *eh;
1772         unsigned int depth, len;
1773         int merge_done = 0, unwritten;
1774
1775         depth = ext_depth(inode);
1776         BUG_ON(path[depth].p_hdr == NULL);
1777         eh = path[depth].p_hdr;
1778
1779         while (ex < EXT_LAST_EXTENT(eh)) {
1780                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1781                         break;
1782                 /* merge with next extent! */
1783                 unwritten = ext4_ext_is_unwritten(ex);
1784                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1785                                 + ext4_ext_get_actual_len(ex + 1));
1786                 if (unwritten)
1787                         ext4_ext_mark_unwritten(ex);
1788
1789                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1790                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1791                                 * sizeof(struct ext4_extent);
1792                         memmove(ex + 1, ex + 2, len);
1793                 }
1794                 le16_add_cpu(&eh->eh_entries, -1);
1795                 merge_done = 1;
1796                 WARN_ON(eh->eh_entries == 0);
1797                 if (!eh->eh_entries)
1798                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1799         }
1800
1801         return merge_done;
1802 }
1803
1804 /*
1805  * This function does a very simple check to see if we can collapse
1806  * an extent tree with a single extent tree leaf block into the inode.
1807  */
1808 static void ext4_ext_try_to_merge_up(handle_t *handle,
1809                                      struct inode *inode,
1810                                      struct ext4_ext_path *path)
1811 {
1812         size_t s;
1813         unsigned max_root = ext4_ext_space_root(inode, 0);
1814         ext4_fsblk_t blk;
1815
1816         if ((path[0].p_depth != 1) ||
1817             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1818             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1819                 return;
1820
1821         /*
1822          * We need to modify the block allocation bitmap and the block
1823          * group descriptor to release the extent tree block.  If we
1824          * can't get the journal credits, give up.
1825          */
1826         if (ext4_journal_extend(handle, 2))
1827                 return;
1828
1829         /*
1830          * Copy the extent data up to the inode
1831          */
1832         blk = ext4_idx_pblock(path[0].p_idx);
1833         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1834                 sizeof(struct ext4_extent_idx);
1835         s += sizeof(struct ext4_extent_header);
1836
1837         path[1].p_maxdepth = path[0].p_maxdepth;
1838         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1839         path[0].p_depth = 0;
1840         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1841                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1842         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1843
1844         brelse(path[1].p_bh);
1845         ext4_free_blocks(handle, inode, NULL, blk, 1,
1846                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1847 }
1848
1849 /*
1850  * This function tries to merge the @ex extent to neighbours in the tree.
1851  * return 1 if merge left else 0.
1852  */
1853 static void ext4_ext_try_to_merge(handle_t *handle,
1854                                   struct inode *inode,
1855                                   struct ext4_ext_path *path,
1856                                   struct ext4_extent *ex) {
1857         struct ext4_extent_header *eh;
1858         unsigned int depth;
1859         int merge_done = 0;
1860
1861         depth = ext_depth(inode);
1862         BUG_ON(path[depth].p_hdr == NULL);
1863         eh = path[depth].p_hdr;
1864
1865         if (ex > EXT_FIRST_EXTENT(eh))
1866                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1867
1868         if (!merge_done)
1869                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1870
1871         ext4_ext_try_to_merge_up(handle, inode, path);
1872 }
1873
1874 /*
1875  * check if a portion of the "newext" extent overlaps with an
1876  * existing extent.
1877  *
1878  * If there is an overlap discovered, it updates the length of the newext
1879  * such that there will be no overlap, and then returns 1.
1880  * If there is no overlap found, it returns 0.
1881  */
1882 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1883                                            struct inode *inode,
1884                                            struct ext4_extent *newext,
1885                                            struct ext4_ext_path *path)
1886 {
1887         ext4_lblk_t b1, b2;
1888         unsigned int depth, len1;
1889         unsigned int ret = 0;
1890
1891         b1 = le32_to_cpu(newext->ee_block);
1892         len1 = ext4_ext_get_actual_len(newext);
1893         depth = ext_depth(inode);
1894         if (!path[depth].p_ext)
1895                 goto out;
1896         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1897
1898         /*
1899          * get the next allocated block if the extent in the path
1900          * is before the requested block(s)
1901          */
1902         if (b2 < b1) {
1903                 b2 = ext4_ext_next_allocated_block(path);
1904                 if (b2 == EXT_MAX_BLOCKS)
1905                         goto out;
1906                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1907         }
1908
1909         /* check for wrap through zero on extent logical start block*/
1910         if (b1 + len1 < b1) {
1911                 len1 = EXT_MAX_BLOCKS - b1;
1912                 newext->ee_len = cpu_to_le16(len1);
1913                 ret = 1;
1914         }
1915
1916         /* check for overlap */
1917         if (b1 + len1 > b2) {
1918                 newext->ee_len = cpu_to_le16(b2 - b1);
1919                 ret = 1;
1920         }
1921 out:
1922         return ret;
1923 }
1924
1925 /*
1926  * ext4_ext_insert_extent:
1927  * tries to merge requsted extent into the existing extent or
1928  * inserts requested extent as new one into the tree,
1929  * creating new leaf in the no-space case.
1930  */
1931 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1932                                 struct ext4_ext_path **ppath,
1933                                 struct ext4_extent *newext, int gb_flags)
1934 {
1935         struct ext4_ext_path *path = *ppath;
1936         struct ext4_extent_header *eh;
1937         struct ext4_extent *ex, *fex;
1938         struct ext4_extent *nearex; /* nearest extent */
1939         struct ext4_ext_path *npath = NULL;
1940         int depth, len, err;
1941         ext4_lblk_t next;
1942         int mb_flags = 0, unwritten;
1943
1944         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1945                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1946         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1947                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1948                 return -EIO;
1949         }
1950         depth = ext_depth(inode);
1951         ex = path[depth].p_ext;
1952         eh = path[depth].p_hdr;
1953         if (unlikely(path[depth].p_hdr == NULL)) {
1954                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1955                 return -EIO;
1956         }
1957
1958         /* try to insert block into found extent and return */
1959         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1960
1961                 /*
1962                  * Try to see whether we should rather test the extent on
1963                  * right from ex, or from the left of ex. This is because
1964                  * ext4_find_extent() can return either extent on the
1965                  * left, or on the right from the searched position. This
1966                  * will make merging more effective.
1967                  */
1968                 if (ex < EXT_LAST_EXTENT(eh) &&
1969                     (le32_to_cpu(ex->ee_block) +
1970                     ext4_ext_get_actual_len(ex) <
1971                     le32_to_cpu(newext->ee_block))) {
1972                         ex += 1;
1973                         goto prepend;
1974                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1975                            (le32_to_cpu(newext->ee_block) +
1976                            ext4_ext_get_actual_len(newext) <
1977                            le32_to_cpu(ex->ee_block)))
1978                         ex -= 1;
1979
1980                 /* Try to append newex to the ex */
1981                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1982                         ext_debug("append [%d]%d block to %u:[%d]%d"
1983                                   "(from %llu)\n",
1984                                   ext4_ext_is_unwritten(newext),
1985                                   ext4_ext_get_actual_len(newext),
1986                                   le32_to_cpu(ex->ee_block),
1987                                   ext4_ext_is_unwritten(ex),
1988                                   ext4_ext_get_actual_len(ex),
1989                                   ext4_ext_pblock(ex));
1990                         err = ext4_ext_get_access(handle, inode,
1991                                                   path + depth);
1992                         if (err)
1993                                 return err;
1994                         unwritten = ext4_ext_is_unwritten(ex);
1995                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1996                                         + ext4_ext_get_actual_len(newext));
1997                         if (unwritten)
1998                                 ext4_ext_mark_unwritten(ex);
1999                         eh = path[depth].p_hdr;
2000                         nearex = ex;
2001                         goto merge;
2002                 }
2003
2004 prepend:
2005                 /* Try to prepend newex to the ex */
2006                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2007                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2008                                   "(from %llu)\n",
2009                                   le32_to_cpu(newext->ee_block),
2010                                   ext4_ext_is_unwritten(newext),
2011                                   ext4_ext_get_actual_len(newext),
2012                                   le32_to_cpu(ex->ee_block),
2013                                   ext4_ext_is_unwritten(ex),
2014                                   ext4_ext_get_actual_len(ex),
2015                                   ext4_ext_pblock(ex));
2016                         err = ext4_ext_get_access(handle, inode,
2017                                                   path + depth);
2018                         if (err)
2019                                 return err;
2020
2021                         unwritten = ext4_ext_is_unwritten(ex);
2022                         ex->ee_block = newext->ee_block;
2023                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2024                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2025                                         + ext4_ext_get_actual_len(newext));
2026                         if (unwritten)
2027                                 ext4_ext_mark_unwritten(ex);
2028                         eh = path[depth].p_hdr;
2029                         nearex = ex;
2030                         goto merge;
2031                 }
2032         }
2033
2034         depth = ext_depth(inode);
2035         eh = path[depth].p_hdr;
2036         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2037                 goto has_space;
2038
2039         /* probably next leaf has space for us? */
2040         fex = EXT_LAST_EXTENT(eh);
2041         next = EXT_MAX_BLOCKS;
2042         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2043                 next = ext4_ext_next_leaf_block(path);
2044         if (next != EXT_MAX_BLOCKS) {
2045                 ext_debug("next leaf block - %u\n", next);
2046                 BUG_ON(npath != NULL);
2047                 npath = ext4_find_extent(inode, next, NULL, 0);
2048                 if (IS_ERR(npath))
2049                         return PTR_ERR(npath);
2050                 BUG_ON(npath->p_depth != path->p_depth);
2051                 eh = npath[depth].p_hdr;
2052                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2053                         ext_debug("next leaf isn't full(%d)\n",
2054                                   le16_to_cpu(eh->eh_entries));
2055                         path = npath;
2056                         goto has_space;
2057                 }
2058                 ext_debug("next leaf has no free space(%d,%d)\n",
2059                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2060         }
2061
2062         /*
2063          * There is no free space in the found leaf.
2064          * We're gonna add a new leaf in the tree.
2065          */
2066         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2067                 mb_flags |= EXT4_MB_USE_RESERVED;
2068         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2069                                        ppath, newext);
2070         if (err)
2071                 goto cleanup;
2072         depth = ext_depth(inode);
2073         eh = path[depth].p_hdr;
2074
2075 has_space:
2076         nearex = path[depth].p_ext;
2077
2078         err = ext4_ext_get_access(handle, inode, path + depth);
2079         if (err)
2080                 goto cleanup;
2081
2082         if (!nearex) {
2083                 /* there is no extent in this leaf, create first one */
2084                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2085                                 le32_to_cpu(newext->ee_block),
2086                                 ext4_ext_pblock(newext),
2087                                 ext4_ext_is_unwritten(newext),
2088                                 ext4_ext_get_actual_len(newext));
2089                 nearex = EXT_FIRST_EXTENT(eh);
2090         } else {
2091                 if (le32_to_cpu(newext->ee_block)
2092                            > le32_to_cpu(nearex->ee_block)) {
2093                         /* Insert after */
2094                         ext_debug("insert %u:%llu:[%d]%d before: "
2095                                         "nearest %p\n",
2096                                         le32_to_cpu(newext->ee_block),
2097                                         ext4_ext_pblock(newext),
2098                                         ext4_ext_is_unwritten(newext),
2099                                         ext4_ext_get_actual_len(newext),
2100                                         nearex);
2101                         nearex++;
2102                 } else {
2103                         /* Insert before */
2104                         BUG_ON(newext->ee_block == nearex->ee_block);
2105                         ext_debug("insert %u:%llu:[%d]%d after: "
2106                                         "nearest %p\n",
2107                                         le32_to_cpu(newext->ee_block),
2108                                         ext4_ext_pblock(newext),
2109                                         ext4_ext_is_unwritten(newext),
2110                                         ext4_ext_get_actual_len(newext),
2111                                         nearex);
2112                 }
2113                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2114                 if (len > 0) {
2115                         ext_debug("insert %u:%llu:[%d]%d: "
2116                                         "move %d extents from 0x%p to 0x%p\n",
2117                                         le32_to_cpu(newext->ee_block),
2118                                         ext4_ext_pblock(newext),
2119                                         ext4_ext_is_unwritten(newext),
2120                                         ext4_ext_get_actual_len(newext),
2121                                         len, nearex, nearex + 1);
2122                         memmove(nearex + 1, nearex,
2123                                 len * sizeof(struct ext4_extent));
2124                 }
2125         }
2126
2127         le16_add_cpu(&eh->eh_entries, 1);
2128         path[depth].p_ext = nearex;
2129         nearex->ee_block = newext->ee_block;
2130         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2131         nearex->ee_len = newext->ee_len;
2132
2133 merge:
2134         /* try to merge extents */
2135         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2136                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2137
2138
2139         /* time to correct all indexes above */
2140         err = ext4_ext_correct_indexes(handle, inode, path);
2141         if (err)
2142                 goto cleanup;
2143
2144         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2145
2146 cleanup:
2147         ext4_ext_drop_refs(npath);
2148         kfree(npath);
2149         return err;
2150 }
2151
2152 static int ext4_fill_fiemap_extents(struct inode *inode,
2153                                     ext4_lblk_t block, ext4_lblk_t num,
2154                                     struct fiemap_extent_info *fieinfo)
2155 {
2156         struct ext4_ext_path *path = NULL;
2157         struct ext4_extent *ex;
2158         struct extent_status es;
2159         ext4_lblk_t next, next_del, start = 0, end = 0;
2160         ext4_lblk_t last = block + num;
2161         int exists, depth = 0, err = 0;
2162         unsigned int flags = 0;
2163         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2164
2165         while (block < last && block != EXT_MAX_BLOCKS) {
2166                 num = last - block;
2167                 /* find extent for this block */
2168                 down_read(&EXT4_I(inode)->i_data_sem);
2169
2170                 path = ext4_find_extent(inode, block, &path, 0);
2171                 if (IS_ERR(path)) {
2172                         up_read(&EXT4_I(inode)->i_data_sem);
2173                         err = PTR_ERR(path);
2174                         path = NULL;
2175                         break;
2176                 }
2177
2178                 depth = ext_depth(inode);
2179                 if (unlikely(path[depth].p_hdr == NULL)) {
2180                         up_read(&EXT4_I(inode)->i_data_sem);
2181                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2182                         err = -EIO;
2183                         break;
2184                 }
2185                 ex = path[depth].p_ext;
2186                 next = ext4_ext_next_allocated_block(path);
2187
2188                 flags = 0;
2189                 exists = 0;
2190                 if (!ex) {
2191                         /* there is no extent yet, so try to allocate
2192                          * all requested space */
2193                         start = block;
2194                         end = block + num;
2195                 } else if (le32_to_cpu(ex->ee_block) > block) {
2196                         /* need to allocate space before found extent */
2197                         start = block;
2198                         end = le32_to_cpu(ex->ee_block);
2199                         if (block + num < end)
2200                                 end = block + num;
2201                 } else if (block >= le32_to_cpu(ex->ee_block)
2202                                         + ext4_ext_get_actual_len(ex)) {
2203                         /* need to allocate space after found extent */
2204                         start = block;
2205                         end = block + num;
2206                         if (end >= next)
2207                                 end = next;
2208                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2209                         /*
2210                          * some part of requested space is covered
2211                          * by found extent
2212                          */
2213                         start = block;
2214                         end = le32_to_cpu(ex->ee_block)
2215                                 + ext4_ext_get_actual_len(ex);
2216                         if (block + num < end)
2217                                 end = block + num;
2218                         exists = 1;
2219                 } else {
2220                         BUG();
2221                 }
2222                 BUG_ON(end <= start);
2223
2224                 if (!exists) {
2225                         es.es_lblk = start;
2226                         es.es_len = end - start;
2227                         es.es_pblk = 0;
2228                 } else {
2229                         es.es_lblk = le32_to_cpu(ex->ee_block);
2230                         es.es_len = ext4_ext_get_actual_len(ex);
2231                         es.es_pblk = ext4_ext_pblock(ex);
2232                         if (ext4_ext_is_unwritten(ex))
2233                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2234                 }
2235
2236                 /*
2237                  * Find delayed extent and update es accordingly. We call
2238                  * it even in !exists case to find out whether es is the
2239                  * last existing extent or not.
2240                  */
2241                 next_del = ext4_find_delayed_extent(inode, &es);
2242                 if (!exists && next_del) {
2243                         exists = 1;
2244                         flags |= (FIEMAP_EXTENT_DELALLOC |
2245                                   FIEMAP_EXTENT_UNKNOWN);
2246                 }
2247                 up_read(&EXT4_I(inode)->i_data_sem);
2248
2249                 if (unlikely(es.es_len == 0)) {
2250                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2251                         err = -EIO;
2252                         break;
2253                 }
2254
2255                 /*
2256                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2257                  * we need to check next == EXT_MAX_BLOCKS because it is
2258                  * possible that an extent is with unwritten and delayed
2259                  * status due to when an extent is delayed allocated and
2260                  * is allocated by fallocate status tree will track both of
2261                  * them in a extent.
2262                  *
2263                  * So we could return a unwritten and delayed extent, and
2264                  * its block is equal to 'next'.
2265                  */
2266                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2267                         flags |= FIEMAP_EXTENT_LAST;
2268                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2269                                      next != EXT_MAX_BLOCKS)) {
2270                                 EXT4_ERROR_INODE(inode,
2271                                                  "next extent == %u, next "
2272                                                  "delalloc extent = %u",
2273                                                  next, next_del);
2274                                 err = -EIO;
2275                                 break;
2276                         }
2277                 }
2278
2279                 if (exists) {
2280                         err = fiemap_fill_next_extent(fieinfo,
2281                                 (__u64)es.es_lblk << blksize_bits,
2282                                 (__u64)es.es_pblk << blksize_bits,
2283                                 (__u64)es.es_len << blksize_bits,
2284                                 flags);
2285                         if (err < 0)
2286                                 break;
2287                         if (err == 1) {
2288                                 err = 0;
2289                                 break;
2290                         }
2291                 }
2292
2293                 block = es.es_lblk + es.es_len;
2294         }
2295
2296         ext4_ext_drop_refs(path);
2297         kfree(path);
2298         return err;
2299 }
2300
2301 /*
2302  * ext4_ext_put_gap_in_cache:
2303  * calculate boundaries of the gap that the requested block fits into
2304  * and cache this gap
2305  */
2306 static void
2307 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
2308                                 ext4_lblk_t block)
2309 {
2310         int depth = ext_depth(inode);
2311         unsigned long len = 0;
2312         ext4_lblk_t lblock = 0;
2313         struct ext4_extent *ex;
2314
2315         ex = path[depth].p_ext;
2316         if (ex == NULL) {
2317                 /*
2318                  * there is no extent yet, so gap is [0;-] and we
2319                  * don't cache it
2320                  */
2321                 ext_debug("cache gap(whole file):");
2322         } else if (block < le32_to_cpu(ex->ee_block)) {
2323                 lblock = block;
2324                 len = le32_to_cpu(ex->ee_block) - block;
2325                 ext_debug("cache gap(before): %u [%u:%u]",
2326                                 block,
2327                                 le32_to_cpu(ex->ee_block),
2328                                  ext4_ext_get_actual_len(ex));
2329                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2330                         ext4_es_insert_extent(inode, lblock, len, ~0,
2331                                               EXTENT_STATUS_HOLE);
2332         } else if (block >= le32_to_cpu(ex->ee_block)
2333                         + ext4_ext_get_actual_len(ex)) {
2334                 ext4_lblk_t next;
2335                 lblock = le32_to_cpu(ex->ee_block)
2336                         + ext4_ext_get_actual_len(ex);
2337
2338                 next = ext4_ext_next_allocated_block(path);
2339                 ext_debug("cache gap(after): [%u:%u] %u",
2340                                 le32_to_cpu(ex->ee_block),
2341                                 ext4_ext_get_actual_len(ex),
2342                                 block);
2343                 BUG_ON(next == lblock);
2344                 len = next - lblock;
2345                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2346                         ext4_es_insert_extent(inode, lblock, len, ~0,
2347                                               EXTENT_STATUS_HOLE);
2348         } else {
2349                 BUG();
2350         }
2351
2352         ext_debug(" -> %u:%lu\n", lblock, len);
2353 }
2354
2355 /*
2356  * ext4_ext_rm_idx:
2357  * removes index from the index block.
2358  */
2359 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2360                         struct ext4_ext_path *path, int depth)
2361 {
2362         int err;
2363         ext4_fsblk_t leaf;
2364
2365         /* free index block */
2366         depth--;
2367         path = path + depth;
2368         leaf = ext4_idx_pblock(path->p_idx);
2369         if (unlikely(path->p_hdr->eh_entries == 0)) {
2370                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2371                 return -EIO;
2372         }
2373         err = ext4_ext_get_access(handle, inode, path);
2374         if (err)
2375                 return err;
2376
2377         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2378                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2379                 len *= sizeof(struct ext4_extent_idx);
2380                 memmove(path->p_idx, path->p_idx + 1, len);
2381         }
2382
2383         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2384         err = ext4_ext_dirty(handle, inode, path);
2385         if (err)
2386                 return err;
2387         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2388         trace_ext4_ext_rm_idx(inode, leaf);
2389
2390         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2391                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2392
2393         while (--depth >= 0) {
2394                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2395                         break;
2396                 path--;
2397                 err = ext4_ext_get_access(handle, inode, path);
2398                 if (err)
2399                         break;
2400                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2401                 err = ext4_ext_dirty(handle, inode, path);
2402                 if (err)
2403                         break;
2404         }
2405         return err;
2406 }
2407
2408 /*
2409  * ext4_ext_calc_credits_for_single_extent:
2410  * This routine returns max. credits that needed to insert an extent
2411  * to the extent tree.
2412  * When pass the actual path, the caller should calculate credits
2413  * under i_data_sem.
2414  */
2415 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2416                                                 struct ext4_ext_path *path)
2417 {
2418         if (path) {
2419                 int depth = ext_depth(inode);
2420                 int ret = 0;
2421
2422                 /* probably there is space in leaf? */
2423                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2424                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2425
2426                         /*
2427                          *  There are some space in the leaf tree, no
2428                          *  need to account for leaf block credit
2429                          *
2430                          *  bitmaps and block group descriptor blocks
2431                          *  and other metadata blocks still need to be
2432                          *  accounted.
2433                          */
2434                         /* 1 bitmap, 1 block group descriptor */
2435                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2436                         return ret;
2437                 }
2438         }
2439
2440         return ext4_chunk_trans_blocks(inode, nrblocks);
2441 }
2442
2443 /*
2444  * How many index/leaf blocks need to change/allocate to add @extents extents?
2445  *
2446  * If we add a single extent, then in the worse case, each tree level
2447  * index/leaf need to be changed in case of the tree split.
2448  *
2449  * If more extents are inserted, they could cause the whole tree split more
2450  * than once, but this is really rare.
2451  */
2452 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2453 {
2454         int index;
2455         int depth;
2456
2457         /* If we are converting the inline data, only one is needed here. */
2458         if (ext4_has_inline_data(inode))
2459                 return 1;
2460
2461         depth = ext_depth(inode);
2462
2463         if (extents <= 1)
2464                 index = depth * 2;
2465         else
2466                 index = depth * 3;
2467
2468         return index;
2469 }
2470
2471 static inline int get_default_free_blocks_flags(struct inode *inode)
2472 {
2473         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2474                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2475         else if (ext4_should_journal_data(inode))
2476                 return EXT4_FREE_BLOCKS_FORGET;
2477         return 0;
2478 }
2479
2480 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2481                               struct ext4_extent *ex,
2482                               long long *partial_cluster,
2483                               ext4_lblk_t from, ext4_lblk_t to)
2484 {
2485         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2486         unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2487         ext4_fsblk_t pblk;
2488         int flags = get_default_free_blocks_flags(inode);
2489
2490         /*
2491          * For bigalloc file systems, we never free a partial cluster
2492          * at the beginning of the extent.  Instead, we make a note
2493          * that we tried freeing the cluster, and check to see if we
2494          * need to free it on a subsequent call to ext4_remove_blocks,
2495          * or at the end of the ext4_truncate() operation.
2496          */
2497         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2498
2499         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2500         /*
2501          * If we have a partial cluster, and it's different from the
2502          * cluster of the last block, we need to explicitly free the
2503          * partial cluster here.
2504          */
2505         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2506         if ((*partial_cluster > 0) &&
2507             (EXT4_B2C(sbi, pblk) != *partial_cluster)) {
2508                 ext4_free_blocks(handle, inode, NULL,
2509                                  EXT4_C2B(sbi, *partial_cluster),
2510                                  sbi->s_cluster_ratio, flags);
2511                 *partial_cluster = 0;
2512         }
2513
2514 #ifdef EXTENTS_STATS
2515         {
2516                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2517                 spin_lock(&sbi->s_ext_stats_lock);
2518                 sbi->s_ext_blocks += ee_len;
2519                 sbi->s_ext_extents++;
2520                 if (ee_len < sbi->s_ext_min)
2521                         sbi->s_ext_min = ee_len;
2522                 if (ee_len > sbi->s_ext_max)
2523                         sbi->s_ext_max = ee_len;
2524                 if (ext_depth(inode) > sbi->s_depth_max)
2525                         sbi->s_depth_max = ext_depth(inode);
2526                 spin_unlock(&sbi->s_ext_stats_lock);
2527         }
2528 #endif
2529         if (from >= le32_to_cpu(ex->ee_block)
2530             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2531                 /* tail removal */
2532                 ext4_lblk_t num;
2533                 unsigned int unaligned;
2534
2535                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2536                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2537                 /*
2538                  * Usually we want to free partial cluster at the end of the
2539                  * extent, except for the situation when the cluster is still
2540                  * used by any other extent (partial_cluster is negative).
2541                  */
2542                 if (*partial_cluster < 0 &&
2543                     -(*partial_cluster) == EXT4_B2C(sbi, pblk + num - 1))
2544                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2545
2546                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2547                           num, pblk, *partial_cluster);
2548                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2549                 /*
2550                  * If the block range to be freed didn't start at the
2551                  * beginning of a cluster, and we removed the entire
2552                  * extent and the cluster is not used by any other extent,
2553                  * save the partial cluster here, since we might need to
2554                  * delete if we determine that the truncate operation has
2555                  * removed all of the blocks in the cluster.
2556                  *
2557                  * On the other hand, if we did not manage to free the whole
2558                  * extent, we have to mark the cluster as used (store negative
2559                  * cluster number in partial_cluster).
2560                  */
2561                 unaligned = EXT4_PBLK_COFF(sbi, pblk);
2562                 if (unaligned && (ee_len == num) &&
2563                     (*partial_cluster != -((long long)EXT4_B2C(sbi, pblk))))
2564                         *partial_cluster = EXT4_B2C(sbi, pblk);
2565                 else if (unaligned)
2566                         *partial_cluster = -((long long)EXT4_B2C(sbi, pblk));
2567                 else if (*partial_cluster > 0)
2568                         *partial_cluster = 0;
2569         } else
2570                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2571                            "%u-%u from %u:%u\n",
2572                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2573         return 0;
2574 }
2575
2576
2577 /*
2578  * ext4_ext_rm_leaf() Removes the extents associated with the
2579  * blocks appearing between "start" and "end", and splits the extents
2580  * if "start" and "end" appear in the same extent
2581  *
2582  * @handle: The journal handle
2583  * @inode:  The files inode
2584  * @path:   The path to the leaf
2585  * @partial_cluster: The cluster which we'll have to free if all extents
2586  *                   has been released from it. It gets negative in case
2587  *                   that the cluster is still used.
2588  * @start:  The first block to remove
2589  * @end:   The last block to remove
2590  */
2591 static int
2592 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2593                  struct ext4_ext_path *path,
2594                  long long *partial_cluster,
2595                  ext4_lblk_t start, ext4_lblk_t end)
2596 {
2597         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2598         int err = 0, correct_index = 0;
2599         int depth = ext_depth(inode), credits;
2600         struct ext4_extent_header *eh;
2601         ext4_lblk_t a, b;
2602         unsigned num;
2603         ext4_lblk_t ex_ee_block;
2604         unsigned short ex_ee_len;
2605         unsigned unwritten = 0;
2606         struct ext4_extent *ex;
2607         ext4_fsblk_t pblk;
2608
2609         /* the header must be checked already in ext4_ext_remove_space() */
2610         ext_debug("truncate since %u in leaf to %u\n", start, end);
2611         if (!path[depth].p_hdr)
2612                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2613         eh = path[depth].p_hdr;
2614         if (unlikely(path[depth].p_hdr == NULL)) {
2615                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2616                 return -EIO;
2617         }
2618         /* find where to start removing */
2619         ex = path[depth].p_ext;
2620         if (!ex)
2621                 ex = EXT_LAST_EXTENT(eh);
2622
2623         ex_ee_block = le32_to_cpu(ex->ee_block);
2624         ex_ee_len = ext4_ext_get_actual_len(ex);
2625
2626         /*
2627          * If we're starting with an extent other than the last one in the
2628          * node, we need to see if it shares a cluster with the extent to
2629          * the right (towards the end of the file). If its leftmost cluster
2630          * is this extent's rightmost cluster and it is not cluster aligned,
2631          * we'll mark it as a partial that is not to be deallocated.
2632          */
2633
2634         if (ex != EXT_LAST_EXTENT(eh)) {
2635                 ext4_fsblk_t current_pblk, right_pblk;
2636                 long long current_cluster, right_cluster;
2637
2638                 current_pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2639                 current_cluster = (long long)EXT4_B2C(sbi, current_pblk);
2640                 right_pblk = ext4_ext_pblock(ex + 1);
2641                 right_cluster = (long long)EXT4_B2C(sbi, right_pblk);
2642                 if (current_cluster == right_cluster &&
2643                         EXT4_PBLK_COFF(sbi, right_pblk))
2644                         *partial_cluster = -right_cluster;
2645         }
2646
2647         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2648
2649         while (ex >= EXT_FIRST_EXTENT(eh) &&
2650                         ex_ee_block + ex_ee_len > start) {
2651
2652                 if (ext4_ext_is_unwritten(ex))
2653                         unwritten = 1;
2654                 else
2655                         unwritten = 0;
2656
2657                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2658                           unwritten, ex_ee_len);
2659                 path[depth].p_ext = ex;
2660
2661                 a = ex_ee_block > start ? ex_ee_block : start;
2662                 b = ex_ee_block+ex_ee_len - 1 < end ?
2663                         ex_ee_block+ex_ee_len - 1 : end;
2664
2665                 ext_debug("  border %u:%u\n", a, b);
2666
2667                 /* If this extent is beyond the end of the hole, skip it */
2668                 if (end < ex_ee_block) {
2669                         /*
2670                          * We're going to skip this extent and move to another,
2671                          * so if this extent is not cluster aligned we have
2672                          * to mark the current cluster as used to avoid
2673                          * accidentally freeing it later on
2674                          */
2675                         pblk = ext4_ext_pblock(ex);
2676                         if (EXT4_PBLK_COFF(sbi, pblk))
2677                                 *partial_cluster =
2678                                         -((long long)EXT4_B2C(sbi, pblk));
2679                         ex--;
2680                         ex_ee_block = le32_to_cpu(ex->ee_block);
2681                         ex_ee_len = ext4_ext_get_actual_len(ex);
2682                         continue;
2683                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2684                         EXT4_ERROR_INODE(inode,
2685                                          "can not handle truncate %u:%u "
2686                                          "on extent %u:%u",
2687                                          start, end, ex_ee_block,
2688                                          ex_ee_block + ex_ee_len - 1);
2689                         err = -EIO;
2690                         goto out;
2691                 } else if (a != ex_ee_block) {
2692                         /* remove tail of the extent */
2693                         num = a - ex_ee_block;
2694                 } else {
2695                         /* remove whole extent: excellent! */
2696                         num = 0;
2697                 }
2698                 /*
2699                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2700                  * descriptor) for each block group; assume two block
2701                  * groups plus ex_ee_len/blocks_per_block_group for
2702                  * the worst case
2703                  */
2704                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2705                 if (ex == EXT_FIRST_EXTENT(eh)) {
2706                         correct_index = 1;
2707                         credits += (ext_depth(inode)) + 1;
2708                 }
2709                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2710
2711                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2712                 if (err)
2713                         goto out;
2714
2715                 err = ext4_ext_get_access(handle, inode, path + depth);
2716                 if (err)
2717                         goto out;
2718
2719                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2720                                          a, b);
2721                 if (err)
2722                         goto out;
2723
2724                 if (num == 0)
2725                         /* this extent is removed; mark slot entirely unused */
2726                         ext4_ext_store_pblock(ex, 0);
2727
2728                 ex->ee_len = cpu_to_le16(num);
2729                 /*
2730                  * Do not mark unwritten if all the blocks in the
2731                  * extent have been removed.
2732                  */
2733                 if (unwritten && num)
2734                         ext4_ext_mark_unwritten(ex);
2735                 /*
2736                  * If the extent was completely released,
2737                  * we need to remove it from the leaf
2738                  */
2739                 if (num == 0) {
2740                         if (end != EXT_MAX_BLOCKS - 1) {
2741                                 /*
2742                                  * For hole punching, we need to scoot all the
2743                                  * extents up when an extent is removed so that
2744                                  * we dont have blank extents in the middle
2745                                  */
2746                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2747                                         sizeof(struct ext4_extent));
2748
2749                                 /* Now get rid of the one at the end */
2750                                 memset(EXT_LAST_EXTENT(eh), 0,
2751                                         sizeof(struct ext4_extent));
2752                         }
2753                         le16_add_cpu(&eh->eh_entries, -1);
2754                 } else if (*partial_cluster > 0)
2755                         *partial_cluster = 0;
2756
2757                 err = ext4_ext_dirty(handle, inode, path + depth);
2758                 if (err)
2759                         goto out;
2760
2761                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2762                                 ext4_ext_pblock(ex));
2763                 ex--;
2764                 ex_ee_block = le32_to_cpu(ex->ee_block);
2765                 ex_ee_len = ext4_ext_get_actual_len(ex);
2766         }
2767
2768         if (correct_index && eh->eh_entries)
2769                 err = ext4_ext_correct_indexes(handle, inode, path);
2770
2771         /*
2772          * If there's a partial cluster and at least one extent remains in
2773          * the leaf, free the partial cluster if it isn't shared with the
2774          * current extent.  If there's a partial cluster and no extents
2775          * remain in the leaf, it can't be freed here.  It can only be
2776          * freed when it's possible to determine if it's not shared with
2777          * any other extent - when the next leaf is processed or when space
2778          * removal is complete.
2779          */
2780         if (*partial_cluster > 0 && eh->eh_entries &&
2781             (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) !=
2782              *partial_cluster)) {
2783                 int flags = get_default_free_blocks_flags(inode);
2784
2785                 ext4_free_blocks(handle, inode, NULL,
2786                                  EXT4_C2B(sbi, *partial_cluster),
2787                                  sbi->s_cluster_ratio, flags);
2788                 *partial_cluster = 0;
2789         }
2790
2791         /* if this leaf is free, then we should
2792          * remove it from index block above */
2793         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2794                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2795
2796 out:
2797         return err;
2798 }
2799
2800 /*
2801  * ext4_ext_more_to_rm:
2802  * returns 1 if current index has to be freed (even partial)
2803  */
2804 static int
2805 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2806 {
2807         BUG_ON(path->p_idx == NULL);
2808
2809         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2810                 return 0;
2811
2812         /*
2813          * if truncate on deeper level happened, it wasn't partial,
2814          * so we have to consider current index for truncation
2815          */
2816         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2817                 return 0;
2818         return 1;
2819 }
2820
2821 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2822                           ext4_lblk_t end)
2823 {
2824         struct super_block *sb = inode->i_sb;
2825         int depth = ext_depth(inode);
2826         struct ext4_ext_path *path = NULL;
2827         long long partial_cluster = 0;
2828         handle_t *handle;
2829         int i = 0, err = 0;
2830
2831         ext_debug("truncate since %u to %u\n", start, end);
2832
2833         /* probably first extent we're gonna free will be last in block */
2834         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2835         if (IS_ERR(handle))
2836                 return PTR_ERR(handle);
2837
2838 again:
2839         trace_ext4_ext_remove_space(inode, start, end, depth);
2840
2841         /*
2842          * Check if we are removing extents inside the extent tree. If that
2843          * is the case, we are going to punch a hole inside the extent tree
2844          * so we have to check whether we need to split the extent covering
2845          * the last block to remove so we can easily remove the part of it
2846          * in ext4_ext_rm_leaf().
2847          */
2848         if (end < EXT_MAX_BLOCKS - 1) {
2849                 struct ext4_extent *ex;
2850                 ext4_lblk_t ee_block;
2851
2852                 /* find extent for this block */
2853                 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2854                 if (IS_ERR(path)) {
2855                         ext4_journal_stop(handle);
2856                         return PTR_ERR(path);
2857                 }
2858                 depth = ext_depth(inode);
2859                 /* Leaf not may not exist only if inode has no blocks at all */
2860                 ex = path[depth].p_ext;
2861                 if (!ex) {
2862                         if (depth) {
2863                                 EXT4_ERROR_INODE(inode,
2864                                                  "path[%d].p_hdr == NULL",
2865                                                  depth);
2866                                 err = -EIO;
2867                         }
2868                         goto out;
2869                 }
2870
2871                 ee_block = le32_to_cpu(ex->ee_block);
2872
2873                 /*
2874                  * See if the last block is inside the extent, if so split
2875                  * the extent at 'end' block so we can easily remove the
2876                  * tail of the first part of the split extent in
2877                  * ext4_ext_rm_leaf().
2878                  */
2879                 if (end >= ee_block &&
2880                     end < ee_block + ext4_ext_get_actual_len(ex) - 1) {
2881                         /*
2882                          * Split the extent in two so that 'end' is the last
2883                          * block in the first new extent. Also we should not
2884                          * fail removing space due to ENOSPC so try to use
2885                          * reserved block if that happens.
2886                          */
2887                         err = ext4_force_split_extent_at(handle, inode, &path,
2888                                                          end + 1, 1);
2889                         if (err < 0)
2890                                 goto out;
2891                 }
2892         }
2893         /*
2894          * We start scanning from right side, freeing all the blocks
2895          * after i_size and walking into the tree depth-wise.
2896          */
2897         depth = ext_depth(inode);
2898         if (path) {
2899                 int k = i = depth;
2900                 while (--k > 0)
2901                         path[k].p_block =
2902                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2903         } else {
2904                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2905                                GFP_NOFS);
2906                 if (path == NULL) {
2907                         ext4_journal_stop(handle);
2908                         return -ENOMEM;
2909                 }
2910                 path[0].p_maxdepth = path[0].p_depth = depth;
2911                 path[0].p_hdr = ext_inode_hdr(inode);
2912                 i = 0;
2913
2914                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2915                         err = -EIO;
2916                         goto out;
2917                 }
2918         }
2919         err = 0;
2920
2921         while (i >= 0 && err == 0) {
2922                 if (i == depth) {
2923                         /* this is leaf block */
2924                         err = ext4_ext_rm_leaf(handle, inode, path,
2925                                                &partial_cluster, start,
2926                                                end);
2927                         /* root level has p_bh == NULL, brelse() eats this */
2928                         brelse(path[i].p_bh);
2929                         path[i].p_bh = NULL;
2930                         i--;
2931                         continue;
2932                 }
2933
2934                 /* this is index block */
2935                 if (!path[i].p_hdr) {
2936                         ext_debug("initialize header\n");
2937                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2938                 }
2939
2940                 if (!path[i].p_idx) {
2941                         /* this level hasn't been touched yet */
2942                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2943                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2944                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2945                                   path[i].p_hdr,
2946                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2947                 } else {
2948                         /* we were already here, see at next index */
2949                         path[i].p_idx--;
2950                 }
2951
2952                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2953                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2954                                 path[i].p_idx);
2955                 if (ext4_ext_more_to_rm(path + i)) {
2956                         struct buffer_head *bh;
2957                         /* go to the next level */
2958                         ext_debug("move to level %d (block %llu)\n",
2959                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2960                         memset(path + i + 1, 0, sizeof(*path));
2961                         bh = read_extent_tree_block(inode,
2962                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2963                                 EXT4_EX_NOCACHE);
2964                         if (IS_ERR(bh)) {
2965                                 /* should we reset i_size? */
2966                                 err = PTR_ERR(bh);
2967                                 break;
2968                         }
2969                         /* Yield here to deal with large extent trees.
2970                          * Should be a no-op if we did IO above. */
2971                         cond_resched();
2972                         if (WARN_ON(i + 1 > depth)) {
2973                                 err = -EIO;
2974                                 break;
2975                         }
2976                         path[i + 1].p_bh = bh;
2977
2978                         /* save actual number of indexes since this
2979                          * number is changed at the next iteration */
2980                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2981                         i++;
2982                 } else {
2983                         /* we finished processing this index, go up */
2984                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2985                                 /* index is empty, remove it;
2986                                  * handle must be already prepared by the
2987                                  * truncatei_leaf() */
2988                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2989                         }
2990                         /* root level has p_bh == NULL, brelse() eats this */
2991                         brelse(path[i].p_bh);
2992                         path[i].p_bh = NULL;
2993                         i--;
2994                         ext_debug("return to level %d\n", i);
2995                 }
2996         }
2997
2998         trace_ext4_ext_remove_space_done(inode, start, end, depth,
2999                         partial_cluster, path->p_hdr->eh_entries);
3000
3001         /* If we still have something in the partial cluster and we have removed
3002          * even the first extent, then we should free the blocks in the partial
3003          * cluster as well. */
3004         if (partial_cluster > 0 && path->p_hdr->eh_entries == 0) {
3005                 int flags = get_default_free_blocks_flags(inode);
3006
3007                 ext4_free_blocks(handle, inode, NULL,
3008                                  EXT4_C2B(EXT4_SB(sb), partial_cluster),
3009                                  EXT4_SB(sb)->s_cluster_ratio, flags);
3010                 partial_cluster = 0;
3011         }
3012
3013         /* TODO: flexible tree reduction should be here */
3014         if (path->p_hdr->eh_entries == 0) {
3015                 /*
3016                  * truncate to zero freed all the tree,
3017                  * so we need to correct eh_depth
3018                  */
3019                 err = ext4_ext_get_access(handle, inode, path);
3020                 if (err == 0) {
3021                         ext_inode_hdr(inode)->eh_depth = 0;
3022                         ext_inode_hdr(inode)->eh_max =
3023                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3024                         err = ext4_ext_dirty(handle, inode, path);
3025                 }
3026         }
3027 out:
3028         ext4_ext_drop_refs(path);
3029         kfree(path);
3030         path = NULL;
3031         if (err == -EAGAIN)
3032                 goto again;
3033         ext4_journal_stop(handle);
3034
3035         return err;
3036 }
3037
3038 /*
3039  * called at mount time
3040  */
3041 void ext4_ext_init(struct super_block *sb)
3042 {
3043         /*
3044          * possible initialization would be here
3045          */
3046
3047         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
3048 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3049                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3050 #ifdef AGGRESSIVE_TEST
3051                        ", aggressive tests"
3052 #endif
3053 #ifdef CHECK_BINSEARCH
3054                        ", check binsearch"
3055 #endif
3056 #ifdef EXTENTS_STATS
3057                        ", stats"
3058 #endif
3059                        "\n");
3060 #endif
3061 #ifdef EXTENTS_STATS
3062                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3063                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3064                 EXT4_SB(sb)->s_ext_max = 0;
3065 #endif
3066         }
3067 }
3068
3069 /*
3070  * called at umount time
3071  */
3072 void ext4_ext_release(struct super_block *sb)
3073 {
3074         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
3075                 return;
3076
3077 #ifdef EXTENTS_STATS
3078         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3079                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3080                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3081                         sbi->s_ext_blocks, sbi->s_ext_extents,
3082                         sbi->s_ext_blocks / sbi->s_ext_extents);
3083                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3084                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3085         }
3086 #endif
3087 }
3088
3089 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3090 {
3091         ext4_lblk_t  ee_block;
3092         ext4_fsblk_t ee_pblock;
3093         unsigned int ee_len;
3094
3095         ee_block  = le32_to_cpu(ex->ee_block);
3096         ee_len    = ext4_ext_get_actual_len(ex);
3097         ee_pblock = ext4_ext_pblock(ex);
3098
3099         if (ee_len == 0)
3100                 return 0;
3101
3102         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3103                                      EXTENT_STATUS_WRITTEN);
3104 }
3105
3106 /* FIXME!! we need to try to merge to left or right after zero-out  */
3107 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3108 {
3109         ext4_fsblk_t ee_pblock;
3110         unsigned int ee_len;
3111         int ret;
3112
3113         ee_len    = ext4_ext_get_actual_len(ex);
3114         ee_pblock = ext4_ext_pblock(ex);
3115
3116         ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
3117         if (ret > 0)
3118                 ret = 0;
3119
3120         return ret;
3121 }
3122
3123 /*
3124  * ext4_split_extent_at() splits an extent at given block.
3125  *
3126  * @handle: the journal handle
3127  * @inode: the file inode
3128  * @path: the path to the extent
3129  * @split: the logical block where the extent is splitted.
3130  * @split_flags: indicates if the extent could be zeroout if split fails, and
3131  *               the states(init or unwritten) of new extents.
3132  * @flags: flags used to insert new extent to extent tree.
3133  *
3134  *
3135  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3136  * of which are deterimined by split_flag.
3137  *
3138  * There are two cases:
3139  *  a> the extent are splitted into two extent.
3140  *  b> split is not needed, and just mark the extent.
3141  *
3142  * return 0 on success.
3143  */
3144 static int ext4_split_extent_at(handle_t *handle,
3145                              struct inode *inode,
3146                              struct ext4_ext_path **ppath,
3147                              ext4_lblk_t split,
3148                              int split_flag,
3149                              int flags)
3150 {
3151         struct ext4_ext_path *path = *ppath;
3152         ext4_fsblk_t newblock;
3153         ext4_lblk_t ee_block;
3154         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3155         struct ext4_extent *ex2 = NULL;
3156         unsigned int ee_len, depth;
3157         int err = 0;
3158
3159         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3160                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3161
3162         ext_debug("ext4_split_extents_at: inode %lu, logical"
3163                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3164
3165         ext4_ext_show_leaf(inode, path);
3166
3167         depth = ext_depth(inode);
3168         ex = path[depth].p_ext;
3169         ee_block = le32_to_cpu(ex->ee_block);
3170         ee_len = ext4_ext_get_actual_len(ex);
3171         newblock = split - ee_block + ext4_ext_pblock(ex);
3172
3173         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3174         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3175                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3176                              EXT4_EXT_MARK_UNWRIT1 |
3177                              EXT4_EXT_MARK_UNWRIT2));
3178
3179         err = ext4_ext_get_access(handle, inode, path + depth);
3180         if (err)
3181                 goto out;
3182
3183         if (split == ee_block) {
3184                 /*
3185                  * case b: block @split is the block that the extent begins with
3186                  * then we just change the state of the extent, and splitting
3187                  * is not needed.
3188                  */
3189                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3190                         ext4_ext_mark_unwritten(ex);
3191                 else
3192                         ext4_ext_mark_initialized(ex);
3193
3194                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3195                         ext4_ext_try_to_merge(handle, inode, path, ex);
3196
3197                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3198                 goto out;
3199         }
3200
3201         /* case a */
3202         memcpy(&orig_ex, ex, sizeof(orig_ex));
3203         ex->ee_len = cpu_to_le16(split - ee_block);
3204         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3205                 ext4_ext_mark_unwritten(ex);
3206
3207         /*
3208          * path may lead to new leaf, not to original leaf any more
3209          * after ext4_ext_insert_extent() returns,
3210          */
3211         err = ext4_ext_dirty(handle, inode, path + depth);
3212         if (err)
3213                 goto fix_extent_len;
3214
3215         ex2 = &newex;
3216         ex2->ee_block = cpu_to_le32(split);
3217         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3218         ext4_ext_store_pblock(ex2, newblock);
3219         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3220                 ext4_ext_mark_unwritten(ex2);
3221
3222         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3223         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3224                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3225                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3226                                 err = ext4_ext_zeroout(inode, ex2);
3227                                 zero_ex.ee_block = ex2->ee_block;
3228                                 zero_ex.ee_len = cpu_to_le16(
3229                                                 ext4_ext_get_actual_len(ex2));
3230                                 ext4_ext_store_pblock(&zero_ex,
3231                                                       ext4_ext_pblock(ex2));
3232                         } else {
3233                                 err = ext4_ext_zeroout(inode, ex);
3234                                 zero_ex.ee_block = ex->ee_block;
3235                                 zero_ex.ee_len = cpu_to_le16(
3236                                                 ext4_ext_get_actual_len(ex));
3237                                 ext4_ext_store_pblock(&zero_ex,
3238                                                       ext4_ext_pblock(ex));
3239                         }
3240                 } else {
3241                         err = ext4_ext_zeroout(inode, &orig_ex);
3242                         zero_ex.ee_block = orig_ex.ee_block;
3243                         zero_ex.ee_len = cpu_to_le16(
3244                                                 ext4_ext_get_actual_len(&orig_ex));
3245                         ext4_ext_store_pblock(&zero_ex,
3246                                               ext4_ext_pblock(&orig_ex));
3247                 }
3248
3249                 if (err)
3250                         goto fix_extent_len;
3251                 /* update the extent length and mark as initialized */
3252                 ex->ee_len = cpu_to_le16(ee_len);
3253                 ext4_ext_try_to_merge(handle, inode, path, ex);
3254                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3255                 if (err)
3256                         goto fix_extent_len;
3257
3258                 /* update extent status tree */
3259                 err = ext4_zeroout_es(inode, &zero_ex);
3260
3261                 goto out;
3262         } else if (err)
3263                 goto fix_extent_len;
3264
3265 out:
3266         ext4_ext_show_leaf(inode, path);
3267         return err;
3268
3269 fix_extent_len:
3270         ex->ee_len = orig_ex.ee_len;
3271         ext4_ext_dirty(handle, inode, path + path->p_depth);
3272         return err;
3273 }
3274
3275 /*
3276  * ext4_split_extents() splits an extent and mark extent which is covered
3277  * by @map as split_flags indicates
3278  *
3279  * It may result in splitting the extent into multiple extents (up to three)
3280  * There are three possibilities:
3281  *   a> There is no split required
3282  *   b> Splits in two extents: Split is happening at either end of the extent
3283  *   c> Splits in three extents: Somone is splitting in middle of the extent
3284  *
3285  */
3286 static int ext4_split_extent(handle_t *handle,
3287                               struct inode *inode,
3288                               struct ext4_ext_path **ppath,
3289                               struct ext4_map_blocks *map,
3290                               int split_flag,
3291                               int flags)
3292 {
3293         struct ext4_ext_path *path = *ppath;
3294         ext4_lblk_t ee_block;
3295         struct ext4_extent *ex;
3296         unsigned int ee_len, depth;
3297         int err = 0;
3298         int unwritten;
3299         int split_flag1, flags1;
3300         int allocated = map->m_len;
3301
3302         depth = ext_depth(inode);
3303         ex = path[depth].p_ext;
3304         ee_block = le32_to_cpu(ex->ee_block);
3305         ee_len = ext4_ext_get_actual_len(ex);
3306         unwritten = ext4_ext_is_unwritten(ex);
3307
3308         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3309                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3310                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3311                 if (unwritten)
3312                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3313                                        EXT4_EXT_MARK_UNWRIT2;
3314                 if (split_flag & EXT4_EXT_DATA_VALID2)
3315                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3316                 err = ext4_split_extent_at(handle, inode, ppath,
3317                                 map->m_lblk + map->m_len, split_flag1, flags1);
3318                 if (err)
3319                         goto out;
3320         } else {
3321                 allocated = ee_len - (map->m_lblk - ee_block);
3322         }
3323         /*
3324          * Update path is required because previous ext4_split_extent_at() may
3325          * result in split of original leaf or extent zeroout.
3326          */
3327         path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3328         if (IS_ERR(path))
3329                 return PTR_ERR(path);
3330         depth = ext_depth(inode);
3331         ex = path[depth].p_ext;
3332         if (!ex) {
3333                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3334                                  (unsigned long) map->m_lblk);
3335                 return -EIO;
3336         }
3337         unwritten = ext4_ext_is_unwritten(ex);
3338         split_flag1 = 0;
3339
3340         if (map->m_lblk >= ee_block) {
3341                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3342                 if (unwritten) {
3343                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3344                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3345                                                      EXT4_EXT_MARK_UNWRIT2);
3346                 }
3347                 err = ext4_split_extent_at(handle, inode, ppath,
3348                                 map->m_lblk, split_flag1, flags);
3349                 if (err)
3350                         goto out;
3351         }
3352
3353         ext4_ext_show_leaf(inode, path);
3354 out:
3355         return err ? err : allocated;
3356 }
3357
3358 /*
3359  * This function is called by ext4_ext_map_blocks() if someone tries to write
3360  * to an unwritten extent. It may result in splitting the unwritten
3361  * extent into multiple extents (up to three - one initialized and two
3362  * unwritten).
3363  * There are three possibilities:
3364  *   a> There is no split required: Entire extent should be initialized
3365  *   b> Splits in two extents: Write is happening at either end of the extent
3366  *   c> Splits in three extents: Somone is writing in middle of the extent
3367  *
3368  * Pre-conditions:
3369  *  - The extent pointed to by 'path' is unwritten.
3370  *  - The extent pointed to by 'path' contains a superset
3371  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3372  *
3373  * Post-conditions on success:
3374  *  - the returned value is the number of blocks beyond map->l_lblk
3375  *    that are allocated and initialized.
3376  *    It is guaranteed to be >= map->m_len.
3377  */
3378 static int ext4_ext_convert_to_initialized(handle_t *handle,
3379                                            struct inode *inode,
3380                                            struct ext4_map_blocks *map,
3381                                            struct ext4_ext_path **ppath,
3382                                            int flags)
3383 {
3384         struct ext4_ext_path *path = *ppath;
3385         struct ext4_sb_info *sbi;
3386         struct ext4_extent_header *eh;
3387         struct ext4_map_blocks split_map;
3388         struct ext4_extent zero_ex;
3389         struct ext4_extent *ex, *abut_ex;
3390         ext4_lblk_t ee_block, eof_block;
3391         unsigned int ee_len, depth, map_len = map->m_len;
3392         int allocated = 0, max_zeroout = 0;
3393         int err = 0;
3394         int split_flag = 0;
3395
3396         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3397                 "block %llu, max_blocks %u\n", inode->i_ino,
3398                 (unsigned long long)map->m_lblk, map_len);
3399
3400         sbi = EXT4_SB(inode->i_sb);
3401         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3402                 inode->i_sb->s_blocksize_bits;
3403         if (eof_block < map->m_lblk + map_len)
3404                 eof_block = map->m_lblk + map_len;
3405
3406         depth = ext_depth(inode);
3407         eh = path[depth].p_hdr;
3408         ex = path[depth].p_ext;
3409         ee_block = le32_to_cpu(ex->ee_block);
3410         ee_len = ext4_ext_get_actual_len(ex);
3411         zero_ex.ee_len = 0;
3412
3413         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3414
3415         /* Pre-conditions */
3416         BUG_ON(!ext4_ext_is_unwritten(ex));
3417         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3418
3419         /*
3420          * Attempt to transfer newly initialized blocks from the currently
3421          * unwritten extent to its neighbor. This is much cheaper
3422          * than an insertion followed by a merge as those involve costly
3423          * memmove() calls. Transferring to the left is the common case in
3424          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3425          * followed by append writes.
3426          *
3427          * Limitations of the current logic:
3428          *  - L1: we do not deal with writes covering the whole extent.
3429          *    This would require removing the extent if the transfer
3430          *    is possible.
3431          *  - L2: we only attempt to merge with an extent stored in the
3432          *    same extent tree node.
3433          */
3434         if ((map->m_lblk == ee_block) &&
3435                 /* See if we can merge left */
3436                 (map_len < ee_len) &&           /*L1*/
3437                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3438                 ext4_lblk_t prev_lblk;
3439                 ext4_fsblk_t prev_pblk, ee_pblk;
3440                 unsigned int prev_len;
3441
3442                 abut_ex = ex - 1;
3443                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3444                 prev_len = ext4_ext_get_actual_len(abut_ex);
3445                 prev_pblk = ext4_ext_pblock(abut_ex);
3446                 ee_pblk = ext4_ext_pblock(ex);
3447
3448                 /*
3449                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3450                  * upon those conditions:
3451                  * - C1: abut_ex is initialized,
3452                  * - C2: abut_ex is logically abutting ex,
3453                  * - C3: abut_ex is physically abutting ex,
3454                  * - C4: abut_ex can receive the additional blocks without
3455                  *   overflowing the (initialized) length limit.
3456                  */
3457                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3458                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3459                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3460                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3461                         err = ext4_ext_get_access(handle, inode, path + depth);
3462                         if (err)
3463                                 goto out;
3464
3465                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3466                                 map, ex, abut_ex);
3467
3468                         /* Shift the start of ex by 'map_len' blocks */
3469                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3470                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3471                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3472                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3473
3474                         /* Extend abut_ex by 'map_len' blocks */
3475                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3476
3477                         /* Result: number of initialized blocks past m_lblk */
3478                         allocated = map_len;
3479                 }
3480         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3481                    (map_len < ee_len) &&        /*L1*/
3482                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3483                 /* See if we can merge right */
3484                 ext4_lblk_t next_lblk;
3485                 ext4_fsblk_t next_pblk, ee_pblk;
3486                 unsigned int next_len;
3487
3488                 abut_ex = ex + 1;
3489                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3490                 next_len = ext4_ext_get_actual_len(abut_ex);
3491                 next_pblk = ext4_ext_pblock(abut_ex);
3492                 ee_pblk = ext4_ext_pblock(ex);
3493
3494                 /*
3495                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3496                  * upon those conditions:
3497                  * - C1: abut_ex is initialized,
3498                  * - C2: abut_ex is logically abutting ex,
3499                  * - C3: abut_ex is physically abutting ex,
3500                  * - C4: abut_ex can receive the additional blocks without
3501                  *   overflowing the (initialized) length limit.
3502                  */
3503                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3504                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3505                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3506                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3507                         err = ext4_ext_get_access(handle, inode, path + depth);
3508                         if (err)
3509                                 goto out;
3510
3511                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3512                                 map, ex, abut_ex);
3513
3514                         /* Shift the start of abut_ex by 'map_len' blocks */
3515                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3516                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3517                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3518                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3519
3520                         /* Extend abut_ex by 'map_len' blocks */
3521                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3522
3523                         /* Result: number of initialized blocks past m_lblk */
3524                         allocated = map_len;
3525                 }
3526         }
3527         if (allocated) {
3528                 /* Mark the block containing both extents as dirty */
3529                 ext4_ext_dirty(handle, inode, path + depth);
3530
3531                 /* Update path to point to the right extent */
3532                 path[depth].p_ext = abut_ex;
3533                 goto out;
3534         } else
3535                 allocated = ee_len - (map->m_lblk - ee_block);
3536
3537         WARN_ON(map->m_lblk < ee_block);
3538         /*
3539          * It is safe to convert extent to initialized via explicit
3540          * zeroout only if extent is fully inside i_size or new_size.
3541          */
3542         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3543
3544         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3545                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3546                         (inode->i_sb->s_blocksize_bits - 10);
3547
3548         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3549         if (max_zeroout && (ee_len <= max_zeroout)) {
3550                 err = ext4_ext_zeroout(inode, ex);
3551                 if (err)
3552                         goto out;
3553                 zero_ex.ee_block = ex->ee_block;
3554                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3555                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3556
3557                 err = ext4_ext_get_access(handle, inode, path + depth);
3558                 if (err)
3559                         goto out;
3560                 ext4_ext_mark_initialized(ex);
3561                 ext4_ext_try_to_merge(handle, inode, path, ex);
3562                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3563                 goto out;
3564         }
3565
3566         /*
3567          * four cases:
3568          * 1. split the extent into three extents.
3569          * 2. split the extent into two extents, zeroout the first half.
3570          * 3. split the extent into two extents, zeroout the second half.
3571          * 4. split the extent into two extents with out zeroout.
3572          */
3573         split_map.m_lblk = map->m_lblk;
3574         split_map.m_len = map->m_len;
3575
3576         if (max_zeroout && (allocated > map->m_len)) {
3577                 if (allocated <= max_zeroout) {
3578                         /* case 3 */
3579                         zero_ex.ee_block =
3580                                          cpu_to_le32(map->m_lblk);
3581                         zero_ex.ee_len = cpu_to_le16(allocated);
3582                         ext4_ext_store_pblock(&zero_ex,
3583                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3584                         err = ext4_ext_zeroout(inode, &zero_ex);
3585                         if (err)
3586                                 goto out;
3587                         split_map.m_lblk = map->m_lblk;
3588                         split_map.m_len = allocated;
3589                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3590                         /* case 2 */
3591                         if (map->m_lblk != ee_block) {
3592                                 zero_ex.ee_block = ex->ee_block;
3593                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3594                                                         ee_block);
3595                                 ext4_ext_store_pblock(&zero_ex,
3596                                                       ext4_ext_pblock(ex));
3597                                 err = ext4_ext_zeroout(inode, &zero_ex);
3598                                 if (err)
3599                                         goto out;
3600                         }
3601
3602                         split_map.m_lblk = ee_block;
3603                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3604                         allocated = map->m_len;
3605                 }
3606         }
3607
3608         allocated = ext4_split_extent(handle, inode, ppath,
3609                                       &split_map, split_flag, flags);
3610         if (allocated < 0)
3611                 err = allocated;
3612
3613 out:
3614         /* If we have gotten a failure, don't zero out status tree */
3615         if (!err)
3616                 err = ext4_zeroout_es(inode, &zero_ex);
3617         return err ? err : allocated;
3618 }
3619
3620 /*
3621  * This function is called by ext4_ext_map_blocks() from
3622  * ext4_get_blocks_dio_write() when DIO to write
3623  * to an unwritten extent.
3624  *
3625  * Writing to an unwritten extent may result in splitting the unwritten
3626  * extent into multiple initialized/unwritten extents (up to three)
3627  * There are three possibilities:
3628  *   a> There is no split required: Entire extent should be unwritten
3629  *   b> Splits in two extents: Write is happening at either end of the extent
3630  *   c> Splits in three extents: Somone is writing in middle of the extent
3631  *
3632  * This works the same way in the case of initialized -> unwritten conversion.
3633  *
3634  * One of more index blocks maybe needed if the extent tree grow after
3635  * the unwritten extent split. To prevent ENOSPC occur at the IO
3636  * complete, we need to split the unwritten extent before DIO submit
3637  * the IO. The unwritten extent called at this time will be split
3638  * into three unwritten extent(at most). After IO complete, the part
3639  * being filled will be convert to initialized by the end_io callback function
3640  * via ext4_convert_unwritten_extents().
3641  *
3642  * Returns the size of unwritten extent to be written on success.
3643  */
3644 static int ext4_split_convert_extents(handle_t *handle,
3645                                         struct inode *inode,
3646                                         struct ext4_map_blocks *map,
3647                                         struct ext4_ext_path **ppath,
3648                                         int flags)
3649 {
3650         struct ext4_ext_path *path = *ppath;
3651         ext4_lblk_t eof_block;
3652         ext4_lblk_t ee_block;
3653         struct ext4_extent *ex;
3654         unsigned int ee_len;
3655         int split_flag = 0, depth;
3656
3657         ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3658                   __func__, inode->i_ino,
3659                   (unsigned long long)map->m_lblk, map->m_len);
3660
3661         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3662                 inode->i_sb->s_blocksize_bits;
3663         if (eof_block < map->m_lblk + map->m_len)
3664                 eof_block = map->m_lblk + map->m_len;
3665         /*
3666          * It is safe to convert extent to initialized via explicit
3667          * zeroout only if extent is fully insde i_size or new_size.
3668          */
3669         depth = ext_depth(inode);
3670         ex = path[depth].p_ext;
3671         ee_block = le32_to_cpu(ex->ee_block);
3672         ee_len = ext4_ext_get_actual_len(ex);
3673
3674         /* Convert to unwritten */
3675         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3676                 split_flag |= EXT4_EXT_DATA_VALID1;
3677         /* Convert to initialized */
3678         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3679                 split_flag |= ee_block + ee_len <= eof_block ?
3680                               EXT4_EXT_MAY_ZEROOUT : 0;
3681                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3682         }
3683         flags |= EXT4_GET_BLOCKS_PRE_IO;
3684         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3685 }
3686
3687 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3688                                                 struct inode *inode,
3689                                                 struct ext4_map_blocks *map,
3690                                                 struct ext4_ext_path **ppath)
3691 {
3692         struct ext4_ext_path *path = *ppath;
3693         struct ext4_extent *ex;
3694         ext4_lblk_t ee_block;
3695         unsigned int ee_len;
3696         int depth;
3697         int err = 0;
3698
3699         depth = ext_depth(inode);
3700         ex = path[depth].p_ext;
3701         ee_block = le32_to_cpu(ex->ee_block);
3702         ee_len = ext4_ext_get_actual_len(ex);
3703
3704         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3705                 "block %llu, max_blocks %u\n", inode->i_ino,
3706                   (unsigned long long)ee_block, ee_len);
3707
3708         /* If extent is larger than requested it is a clear sign that we still
3709          * have some extent state machine issues left. So extent_split is still
3710          * required.
3711          * TODO: Once all related issues will be fixed this situation should be
3712          * illegal.
3713          */
3714         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3715 #ifdef EXT4_DEBUG
3716                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3717                              " len %u; IO logical block %llu, len %u\n",
3718                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3719                              (unsigned long long)map->m_lblk, map->m_len);
3720 #endif
3721                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3722                                                  EXT4_GET_BLOCKS_CONVERT);
3723                 if (err < 0)
3724                         return err;
3725                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3726                 if (IS_ERR(path))
3727                         return PTR_ERR(path);
3728                 depth = ext_depth(inode);
3729                 ex = path[depth].p_ext;
3730         }
3731
3732         err = ext4_ext_get_access(handle, inode, path + depth);
3733         if (err)
3734                 goto out;
3735         /* first mark the extent as initialized */
3736         ext4_ext_mark_initialized(ex);
3737
3738         /* note: ext4_ext_correct_indexes() isn't needed here because
3739          * borders are not changed
3740          */
3741         ext4_ext_try_to_merge(handle, inode, path, ex);
3742
3743         /* Mark modified extent as dirty */
3744         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3745 out:
3746         ext4_ext_show_leaf(inode, path);
3747         return err;
3748 }
3749
3750 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3751                         sector_t block, int count)
3752 {
3753         int i;
3754         for (i = 0; i < count; i++)
3755                 unmap_underlying_metadata(bdev, block + i);
3756 }
3757
3758 /*
3759  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3760  */
3761 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3762                               ext4_lblk_t lblk,
3763                               struct ext4_ext_path *path,
3764                               unsigned int len)
3765 {
3766         int i, depth;
3767         struct ext4_extent_header *eh;
3768         struct ext4_extent *last_ex;
3769
3770         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3771                 return 0;
3772
3773         depth = ext_depth(inode);
3774         eh = path[depth].p_hdr;
3775
3776         /*
3777          * We're going to remove EOFBLOCKS_FL entirely in future so we
3778          * do not care for this case anymore. Simply remove the flag
3779          * if there are no extents.
3780          */
3781         if (unlikely(!eh->eh_entries))
3782                 goto out;
3783         last_ex = EXT_LAST_EXTENT(eh);
3784         /*
3785          * We should clear the EOFBLOCKS_FL flag if we are writing the
3786          * last block in the last extent in the file.  We test this by
3787          * first checking to see if the caller to
3788          * ext4_ext_get_blocks() was interested in the last block (or
3789          * a block beyond the last block) in the current extent.  If
3790          * this turns out to be false, we can bail out from this
3791          * function immediately.
3792          */
3793         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3794             ext4_ext_get_actual_len(last_ex))
3795                 return 0;
3796         /*
3797          * If the caller does appear to be planning to write at or
3798          * beyond the end of the current extent, we then test to see
3799          * if the current extent is the last extent in the file, by
3800          * checking to make sure it was reached via the rightmost node
3801          * at each level of the tree.
3802          */
3803         for (i = depth-1; i >= 0; i--)
3804                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3805                         return 0;
3806 out:
3807         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3808         return ext4_mark_inode_dirty(handle, inode);
3809 }
3810
3811 /**
3812  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3813  *
3814  * Return 1 if there is a delalloc block in the range, otherwise 0.
3815  */
3816 int ext4_find_delalloc_range(struct inode *inode,
3817                              ext4_lblk_t lblk_start,
3818                              ext4_lblk_t lblk_end)
3819 {
3820         struct extent_status es;
3821
3822         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3823         if (es.es_len == 0)
3824                 return 0; /* there is no delay extent in this tree */
3825         else if (es.es_lblk <= lblk_start &&
3826                  lblk_start < es.es_lblk + es.es_len)
3827                 return 1;
3828         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3829                 return 1;
3830         else
3831                 return 0;
3832 }
3833
3834 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3835 {
3836         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3837         ext4_lblk_t lblk_start, lblk_end;
3838         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3839         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3840
3841         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3842 }
3843
3844 /**
3845  * Determines how many complete clusters (out of those specified by the 'map')
3846  * are under delalloc and were reserved quota for.
3847  * This function is called when we are writing out the blocks that were
3848  * originally written with their allocation delayed, but then the space was
3849  * allocated using fallocate() before the delayed allocation could be resolved.
3850  * The cases to look for are:
3851  * ('=' indicated delayed allocated blocks
3852  *  '-' indicates non-delayed allocated blocks)
3853  * (a) partial clusters towards beginning and/or end outside of allocated range
3854  *     are not delalloc'ed.
3855  *      Ex:
3856  *      |----c---=|====c====|====c====|===-c----|
3857  *               |++++++ allocated ++++++|
3858  *      ==> 4 complete clusters in above example
3859  *
3860  * (b) partial cluster (outside of allocated range) towards either end is
3861  *     marked for delayed allocation. In this case, we will exclude that
3862  *     cluster.
3863  *      Ex:
3864  *      |----====c========|========c========|
3865  *           |++++++ allocated ++++++|
3866  *      ==> 1 complete clusters in above example
3867  *
3868  *      Ex:
3869  *      |================c================|
3870  *            |++++++ allocated ++++++|
3871  *      ==> 0 complete clusters in above example
3872  *
3873  * The ext4_da_update_reserve_space will be called only if we
3874  * determine here that there were some "entire" clusters that span
3875  * this 'allocated' range.
3876  * In the non-bigalloc case, this function will just end up returning num_blks
3877  * without ever calling ext4_find_delalloc_range.
3878  */
3879 static unsigned int
3880 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3881                            unsigned int num_blks)
3882 {
3883         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3884         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3885         ext4_lblk_t lblk_from, lblk_to, c_offset;
3886         unsigned int allocated_clusters = 0;
3887
3888         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3889         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3890
3891         /* max possible clusters for this allocation */
3892         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3893
3894         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3895
3896         /* Check towards left side */
3897         c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3898         if (c_offset) {
3899                 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3900                 lblk_to = lblk_from + c_offset - 1;
3901
3902                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3903                         allocated_clusters--;
3904         }
3905
3906         /* Now check towards right. */
3907         c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3908         if (allocated_clusters && c_offset) {
3909                 lblk_from = lblk_start + num_blks;
3910                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3911
3912                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3913                         allocated_clusters--;
3914         }
3915
3916         return allocated_clusters;
3917 }
3918
3919 static int
3920 convert_initialized_extent(handle_t *handle, struct inode *inode,
3921                            struct ext4_map_blocks *map,
3922                            struct ext4_ext_path **ppath, int flags,
3923                            unsigned int allocated, ext4_fsblk_t newblock)
3924 {
3925         struct ext4_ext_path *path = *ppath;
3926         struct ext4_extent *ex;
3927         ext4_lblk_t ee_block;
3928         unsigned int ee_len;
3929         int depth;
3930         int err = 0;
3931
3932         /*
3933          * Make sure that the extent is no bigger than we support with
3934          * unwritten extent
3935          */
3936         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3937                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3938
3939         depth = ext_depth(inode);
3940         ex = path[depth].p_ext;
3941         ee_block = le32_to_cpu(ex->ee_block);
3942         ee_len = ext4_ext_get_actual_len(ex);
3943
3944         ext_debug("%s: inode %lu, logical"
3945                 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3946                   (unsigned long long)ee_block, ee_len);
3947
3948         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3949                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3950                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3951                 if (err < 0)
3952                         return err;
3953                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3954                 if (IS_ERR(path))
3955                         return PTR_ERR(path);
3956                 depth = ext_depth(inode);
3957                 ex = path[depth].p_ext;
3958                 if (!ex) {
3959                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3960                                          (unsigned long) map->m_lblk);
3961                         return -EIO;
3962                 }
3963         }
3964
3965         err = ext4_ext_get_access(handle, inode, path + depth);
3966         if (err)
3967                 return err;
3968         /* first mark the extent as unwritten */
3969         ext4_ext_mark_unwritten(ex);
3970
3971         /* note: ext4_ext_correct_indexes() isn't needed here because
3972          * borders are not changed
3973          */
3974         ext4_ext_try_to_merge(handle, inode, path, ex);
3975
3976         /* Mark modified extent as dirty */
3977         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3978         if (err)
3979                 return err;
3980         ext4_ext_show_leaf(inode, path);
3981
3982         ext4_update_inode_fsync_trans(handle, inode, 1);
3983         err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
3984         if (err)
3985                 return err;
3986         map->m_flags |= EXT4_MAP_UNWRITTEN;
3987         if (allocated > map->m_len)
3988                 allocated = map->m_len;
3989         map->m_len = allocated;
3990         return allocated;
3991 }
3992
3993 static int
3994 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3995                         struct ext4_map_blocks *map,
3996                         struct ext4_ext_path **ppath, int flags,
3997                         unsigned int allocated, ext4_fsblk_t newblock)
3998 {
3999         struct ext4_ext_path *path = *ppath;
4000         int ret = 0;
4001         int err = 0;
4002         ext4_io_end_t *io = ext4_inode_aio(inode);
4003
4004         ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4005                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
4006                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4007                   flags, allocated);
4008         ext4_ext_show_leaf(inode, path);
4009
4010         /*
4011          * When writing into unwritten space, we should not fail to
4012          * allocate metadata blocks for the new extent block if needed.
4013          */
4014         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4015
4016         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4017                                                     allocated, newblock);
4018
4019         /* get_block() before submit the IO, split the extent */
4020         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4021                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4022                                          flags | EXT4_GET_BLOCKS_CONVERT);
4023                 if (ret <= 0)
4024                         goto out;
4025                 /*
4026                  * Flag the inode(non aio case) or end_io struct (aio case)
4027                  * that this IO needs to conversion to written when IO is
4028                  * completed
4029                  */
4030                 if (io)
4031                         ext4_set_io_unwritten_flag(inode, io);
4032                 else
4033                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
4034                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4035                 goto out;
4036         }
4037         /* IO end_io complete, convert the filled extent to written */
4038         if (flags & EXT4_GET_BLOCKS_CONVERT) {
4039                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4040                                                            ppath);
4041                 if (ret >= 0) {
4042                         ext4_update_inode_fsync_trans(handle, inode, 1);
4043                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
4044                                                  path, map->m_len);
4045                 } else
4046                         err = ret;
4047                 map->m_flags |= EXT4_MAP_MAPPED;
4048                 map->m_pblk = newblock;
4049                 if (allocated > map->m_len)
4050                         allocated = map->m_len;
4051                 map->m_len = allocated;
4052                 goto out2;
4053         }
4054         /* buffered IO case */
4055         /*
4056          * repeat fallocate creation request
4057          * we already have an unwritten extent
4058          */
4059         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4060                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4061                 goto map_out;
4062         }
4063
4064         /* buffered READ or buffered write_begin() lookup */
4065         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4066                 /*
4067                  * We have blocks reserved already.  We
4068                  * return allocated blocks so that delalloc
4069                  * won't do block reservation for us.  But
4070                  * the buffer head will be unmapped so that
4071                  * a read from the block returns 0s.
4072                  */
4073                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4074                 goto out1;
4075         }
4076
4077         /* buffered write, writepage time, convert*/
4078         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4079         if (ret >= 0)
4080                 ext4_update_inode_fsync_trans(handle, inode, 1);
4081 out:
4082         if (ret <= 0) {
4083                 err = ret;
4084                 goto out2;
4085         } else
4086                 allocated = ret;
4087         map->m_flags |= EXT4_MAP_NEW;
4088         /*
4089          * if we allocated more blocks than requested
4090          * we need to make sure we unmap the extra block
4091          * allocated. The actual needed block will get
4092          * unmapped later when we find the buffer_head marked
4093          * new.
4094          */
4095         if (allocated > map->m_len) {
4096                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4097                                         newblock + map->m_len,
4098                                         allocated - map->m_len);
4099                 allocated = map->m_len;
4100         }
4101         map->m_len = allocated;
4102
4103         /*
4104          * If we have done fallocate with the offset that is already
4105          * delayed allocated, we would have block reservation
4106          * and quota reservation done in the delayed write path.
4107          * But fallocate would have already updated quota and block
4108          * count for this offset. So cancel these reservation
4109          */
4110         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4111                 unsigned int reserved_clusters;
4112                 reserved_clusters = get_reserved_cluster_alloc(inode,
4113                                 map->m_lblk, map->m_len);
4114                 if (reserved_clusters)
4115                         ext4_da_update_reserve_space(inode,
4116                                                      reserved_clusters,
4117                                                      0);
4118         }
4119
4120 map_out:
4121         map->m_flags |= EXT4_MAP_MAPPED;
4122         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4123                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4124                                          map->m_len);
4125                 if (err < 0)
4126                         goto out2;
4127         }
4128 out1:
4129         if (allocated > map->m_len)
4130                 allocated = map->m_len;
4131         ext4_ext_show_leaf(inode, path);
4132         map->m_pblk = newblock;
4133         map->m_len = allocated;
4134 out2:
4135         return err ? err : allocated;
4136 }
4137
4138 /*
4139  * get_implied_cluster_alloc - check to see if the requested
4140  * allocation (in the map structure) overlaps with a cluster already
4141  * allocated in an extent.
4142  *      @sb     The filesystem superblock structure
4143  *      @map    The requested lblk->pblk mapping
4144  *      @ex     The extent structure which might contain an implied
4145  *                      cluster allocation
4146  *
4147  * This function is called by ext4_ext_map_blocks() after we failed to
4148  * find blocks that were already in the inode's extent tree.  Hence,
4149  * we know that the beginning of the requested region cannot overlap
4150  * the extent from the inode's extent tree.  There are three cases we
4151  * want to catch.  The first is this case:
4152  *
4153  *               |--- cluster # N--|
4154  *    |--- extent ---|  |---- requested region ---|
4155  *                      |==========|
4156  *
4157  * The second case that we need to test for is this one:
4158  *
4159  *   |--------- cluster # N ----------------|
4160  *         |--- requested region --|   |------- extent ----|
4161  *         |=======================|
4162  *
4163  * The third case is when the requested region lies between two extents
4164  * within the same cluster:
4165  *          |------------- cluster # N-------------|
4166  * |----- ex -----|                  |---- ex_right ----|
4167  *                  |------ requested region ------|
4168  *                  |================|
4169  *
4170  * In each of the above cases, we need to set the map->m_pblk and
4171  * map->m_len so it corresponds to the return the extent labelled as
4172  * "|====|" from cluster #N, since it is already in use for data in
4173  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4174  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4175  * as a new "allocated" block region.  Otherwise, we will return 0 and
4176  * ext4_ext_map_blocks() will then allocate one or more new clusters
4177  * by calling ext4_mb_new_blocks().
4178  */
4179 static int get_implied_cluster_alloc(struct super_block *sb,
4180                                      struct ext4_map_blocks *map,
4181                                      struct ext4_extent *ex,
4182                                      struct ext4_ext_path *path)
4183 {
4184         struct ext4_sb_info *sbi = EXT4_SB(sb);
4185         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4186         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4187         ext4_lblk_t rr_cluster_start;
4188         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4189         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4190         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4191
4192         /* The extent passed in that we are trying to match */
4193         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4194         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4195
4196         /* The requested region passed into ext4_map_blocks() */
4197         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4198
4199         if ((rr_cluster_start == ex_cluster_end) ||
4200             (rr_cluster_start == ex_cluster_start)) {
4201                 if (rr_cluster_start == ex_cluster_end)
4202                         ee_start += ee_len - 1;
4203                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4204                 map->m_len = min(map->m_len,
4205                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4206                 /*
4207                  * Check for and handle this case:
4208                  *
4209                  *   |--------- cluster # N-------------|
4210                  *                     |------- extent ----|
4211                  *         |--- requested region ---|
4212                  *         |===========|
4213                  */
4214
4215                 if (map->m_lblk < ee_block)
4216                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4217
4218                 /*
4219                  * Check for the case where there is already another allocated
4220                  * block to the right of 'ex' but before the end of the cluster.
4221                  *
4222                  *          |------------- cluster # N-------------|
4223                  * |----- ex -----|                  |---- ex_right ----|
4224                  *                  |------ requested region ------|
4225                  *                  |================|
4226                  */
4227                 if (map->m_lblk > ee_block) {
4228                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4229                         map->m_len = min(map->m_len, next - map->m_lblk);
4230                 }
4231
4232                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4233                 return 1;
4234         }
4235
4236         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4237         return 0;
4238 }
4239
4240
4241 /*
4242  * Block allocation/map/preallocation routine for extents based files
4243  *
4244  *
4245  * Need to be called with
4246  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4247  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4248  *
4249  * return > 0, number of of blocks already mapped/allocated
4250  *          if create == 0 and these are pre-allocated blocks
4251  *              buffer head is unmapped
4252  *          otherwise blocks are mapped
4253  *
4254  * return = 0, if plain look up failed (blocks have not been allocated)
4255  *          buffer head is unmapped
4256  *
4257  * return < 0, error case.
4258  */
4259 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4260                         struct ext4_map_blocks *map, int flags)
4261 {
4262         struct ext4_ext_path *path = NULL;
4263         struct ext4_extent newex, *ex, *ex2;
4264         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4265         ext4_fsblk_t newblock = 0;
4266         int free_on_err = 0, err = 0, depth, ret;
4267         unsigned int allocated = 0, offset = 0;
4268         unsigned int allocated_clusters = 0;
4269         struct ext4_allocation_request ar;
4270         ext4_io_end_t *io = ext4_inode_aio(inode);
4271         ext4_lblk_t cluster_offset;
4272         int set_unwritten = 0;
4273
4274         ext_debug("blocks %u/%u requested for inode %lu\n",
4275                   map->m_lblk, map->m_len, inode->i_ino);
4276         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4277
4278         /* find extent for this block */
4279         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4280         if (IS_ERR(path)) {
4281                 err = PTR_ERR(path);
4282                 path = NULL;
4283                 goto out2;
4284         }
4285
4286         depth = ext_depth(inode);
4287
4288         /*
4289          * consistent leaf must not be empty;
4290          * this situation is possible, though, _during_ tree modification;
4291          * this is why assert can't be put in ext4_find_extent()
4292          */
4293         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4294                 EXT4_ERROR_INODE(inode, "bad extent address "
4295                                  "lblock: %lu, depth: %d pblock %lld",
4296                                  (unsigned long) map->m_lblk, depth,
4297                                  path[depth].p_block);
4298                 err = -EIO;
4299                 goto out2;
4300         }
4301
4302         ex = path[depth].p_ext;
4303         if (ex) {
4304                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4305                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4306                 unsigned short ee_len;
4307
4308
4309                 /*
4310                  * unwritten extents are treated as holes, except that
4311                  * we split out initialized portions during a write.
4312                  */
4313                 ee_len = ext4_ext_get_actual_len(ex);
4314
4315                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4316
4317                 /* if found extent covers block, simply return it */
4318                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4319                         newblock = map->m_lblk - ee_block + ee_start;
4320                         /* number of remaining blocks in the extent */
4321                         allocated = ee_len - (map->m_lblk - ee_block);
4322                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4323                                   ee_block, ee_len, newblock);
4324
4325                         /*
4326                          * If the extent is initialized check whether the
4327                          * caller wants to convert it to unwritten.
4328                          */
4329                         if ((!ext4_ext_is_unwritten(ex)) &&
4330                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4331                                 allocated = convert_initialized_extent(
4332                                                 handle, inode, map, &path,
4333                                                 flags, allocated, newblock);
4334                                 goto out2;
4335                         } else if (!ext4_ext_is_unwritten(ex))
4336                                 goto out;
4337
4338                         ret = ext4_ext_handle_unwritten_extents(
4339                                 handle, inode, map, &path, flags,
4340                                 allocated, newblock);
4341                         if (ret < 0)
4342                                 err = ret;
4343                         else
4344                                 allocated = ret;
4345                         goto out2;
4346                 }
4347         }
4348
4349         if ((sbi->s_cluster_ratio > 1) &&
4350             ext4_find_delalloc_cluster(inode, map->m_lblk))
4351                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4352
4353         /*
4354          * requested block isn't allocated yet;
4355          * we couldn't try to create block if create flag is zero
4356          */
4357         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4358                 /*
4359                  * put just found gap into cache to speed up
4360                  * subsequent requests
4361                  */
4362                 if ((flags & EXT4_GET_BLOCKS_NO_PUT_HOLE) == 0)
4363                         ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
4364                 goto out2;
4365         }
4366
4367         /*
4368          * Okay, we need to do block allocation.
4369          */
4370         map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
4371         newex.ee_block = cpu_to_le32(map->m_lblk);
4372         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4373
4374         /*
4375          * If we are doing bigalloc, check to see if the extent returned
4376          * by ext4_find_extent() implies a cluster we can use.
4377          */
4378         if (cluster_offset && ex &&
4379             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4380                 ar.len = allocated = map->m_len;
4381                 newblock = map->m_pblk;
4382                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4383                 goto got_allocated_blocks;
4384         }
4385
4386         /* find neighbour allocated blocks */
4387         ar.lleft = map->m_lblk;
4388         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4389         if (err)
4390                 goto out2;
4391         ar.lright = map->m_lblk;
4392         ex2 = NULL;
4393         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4394         if (err)
4395                 goto out2;
4396
4397         /* Check if the extent after searching to the right implies a
4398          * cluster we can use. */
4399         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4400             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4401                 ar.len = allocated = map->m_len;
4402                 newblock = map->m_pblk;
4403                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4404                 goto got_allocated_blocks;
4405         }
4406
4407         /*
4408          * See if request is beyond maximum number of blocks we can have in
4409          * a single extent. For an initialized extent this limit is
4410          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4411          * EXT_UNWRITTEN_MAX_LEN.
4412          */
4413         if (map->m_len > EXT_INIT_MAX_LEN &&
4414             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4415                 map->m_len = EXT_INIT_MAX_LEN;
4416         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4417                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4418                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4419
4420         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4421         newex.ee_len = cpu_to_le16(map->m_len);
4422         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4423         if (err)
4424                 allocated = ext4_ext_get_actual_len(&newex);
4425         else
4426                 allocated = map->m_len;
4427
4428         /* allocate new block */
4429         ar.inode = inode;
4430         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4431         ar.logical = map->m_lblk;
4432         /*
4433          * We calculate the offset from the beginning of the cluster
4434          * for the logical block number, since when we allocate a
4435          * physical cluster, the physical block should start at the
4436          * same offset from the beginning of the cluster.  This is
4437          * needed so that future calls to get_implied_cluster_alloc()
4438          * work correctly.
4439          */
4440         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4441         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4442         ar.goal -= offset;
4443         ar.logical -= offset;
4444         if (S_ISREG(inode->i_mode))
4445                 ar.flags = EXT4_MB_HINT_DATA;
4446         else
4447                 /* disable in-core preallocation for non-regular files */
4448                 ar.flags = 0;
4449         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4450                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4451         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4452                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4453         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4454         if (!newblock)
4455                 goto out2;
4456         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4457                   ar.goal, newblock, allocated);
4458         free_on_err = 1;
4459         allocated_clusters = ar.len;
4460         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4461         if (ar.len > allocated)
4462                 ar.len = allocated;
4463
4464 got_allocated_blocks:
4465         /* try to insert new extent into found leaf and return */
4466         ext4_ext_store_pblock(&newex, newblock + offset);
4467         newex.ee_len = cpu_to_le16(ar.len);
4468         /* Mark unwritten */
4469         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4470                 ext4_ext_mark_unwritten(&newex);
4471                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4472                 /*
4473                  * io_end structure was created for every IO write to an
4474                  * unwritten extent. To avoid unnecessary conversion,
4475                  * here we flag the IO that really needs the conversion.
4476                  * For non asycn direct IO case, flag the inode state
4477                  * that we need to perform conversion when IO is done.
4478                  */
4479                 if (flags & EXT4_GET_BLOCKS_PRE_IO)
4480                         set_unwritten = 1;
4481         }
4482
4483         err = 0;
4484         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4485                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4486                                          path, ar.len);
4487         if (!err)
4488                 err = ext4_ext_insert_extent(handle, inode, &path,
4489                                              &newex, flags);
4490
4491         if (!err && set_unwritten) {
4492                 if (io)
4493                         ext4_set_io_unwritten_flag(inode, io);
4494                 else
4495                         ext4_set_inode_state(inode,
4496                                              EXT4_STATE_DIO_UNWRITTEN);
4497         }
4498
4499         if (err && free_on_err) {
4500                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4501                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4502                 /* free data blocks we just allocated */
4503                 /* not a good idea to call discard here directly,
4504                  * but otherwise we'd need to call it every free() */
4505                 ext4_discard_preallocations(inode);
4506                 ext4_free_blocks(handle, inode, NULL, newblock,
4507                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4508                 goto out2;
4509         }
4510
4511         /* previous routine could use block we allocated */
4512         newblock = ext4_ext_pblock(&newex);
4513         allocated = ext4_ext_get_actual_len(&newex);
4514         if (allocated > map->m_len)
4515                 allocated = map->m_len;
4516         map->m_flags |= EXT4_MAP_NEW;
4517
4518         /*
4519          * Update reserved blocks/metadata blocks after successful
4520          * block allocation which had been deferred till now.
4521          */
4522         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4523                 unsigned int reserved_clusters;
4524                 /*
4525                  * Check how many clusters we had reserved this allocated range
4526                  */
4527                 reserved_clusters = get_reserved_cluster_alloc(inode,
4528                                                 map->m_lblk, allocated);
4529                 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) {
4530                         if (reserved_clusters) {
4531                                 /*
4532                                  * We have clusters reserved for this range.
4533                                  * But since we are not doing actual allocation
4534                                  * and are simply using blocks from previously
4535                                  * allocated cluster, we should release the
4536                                  * reservation and not claim quota.
4537                                  */
4538                                 ext4_da_update_reserve_space(inode,
4539                                                 reserved_clusters, 0);
4540                         }
4541                 } else {
4542                         BUG_ON(allocated_clusters < reserved_clusters);
4543                         if (reserved_clusters < allocated_clusters) {
4544                                 struct ext4_inode_info *ei = EXT4_I(inode);
4545                                 int reservation = allocated_clusters -
4546                                                   reserved_clusters;
4547                                 /*
4548                                  * It seems we claimed few clusters outside of
4549                                  * the range of this allocation. We should give
4550                                  * it back to the reservation pool. This can
4551                                  * happen in the following case:
4552                                  *
4553                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4554                                  *   cluster has 4 blocks. Thus, the clusters
4555                                  *   are [0-3],[4-7],[8-11]...
4556                                  * * First comes delayed allocation write for
4557                                  *   logical blocks 10 & 11. Since there were no
4558                                  *   previous delayed allocated blocks in the
4559                                  *   range [8-11], we would reserve 1 cluster
4560                                  *   for this write.
4561                                  * * Next comes write for logical blocks 3 to 8.
4562                                  *   In this case, we will reserve 2 clusters
4563                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4564                                  *   that range has a delayed allocated blocks.
4565                                  *   Thus total reserved clusters now becomes 3.
4566                                  * * Now, during the delayed allocation writeout
4567                                  *   time, we will first write blocks [3-8] and
4568                                  *   allocate 3 clusters for writing these
4569                                  *   blocks. Also, we would claim all these
4570                                  *   three clusters above.
4571                                  * * Now when we come here to writeout the
4572                                  *   blocks [10-11], we would expect to claim
4573                                  *   the reservation of 1 cluster we had made
4574                                  *   (and we would claim it since there are no
4575                                  *   more delayed allocated blocks in the range
4576                                  *   [8-11]. But our reserved cluster count had
4577                                  *   already gone to 0.
4578                                  *
4579                                  *   Thus, at the step 4 above when we determine
4580                                  *   that there are still some unwritten delayed
4581                                  *   allocated blocks outside of our current
4582                                  *   block range, we should increment the
4583                                  *   reserved clusters count so that when the
4584                                  *   remaining blocks finally gets written, we
4585                                  *   could claim them.
4586                                  */
4587                                 dquot_reserve_block(inode,
4588                                                 EXT4_C2B(sbi, reservation));
4589                                 spin_lock(&ei->i_block_reservation_lock);
4590                                 ei->i_reserved_data_blocks += reservation;
4591                                 spin_unlock(&ei->i_block_reservation_lock);
4592                         }
4593                         /*
4594                          * We will claim quota for all newly allocated blocks.
4595                          * We're updating the reserved space *after* the
4596                          * correction above so we do not accidentally free
4597                          * all the metadata reservation because we might
4598                          * actually need it later on.
4599                          */
4600                         ext4_da_update_reserve_space(inode, allocated_clusters,
4601                                                         1);
4602                 }
4603         }
4604
4605         /*
4606          * Cache the extent and update transaction to commit on fdatasync only
4607          * when it is _not_ an unwritten extent.
4608          */
4609         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4610                 ext4_update_inode_fsync_trans(handle, inode, 1);
4611         else
4612                 ext4_update_inode_fsync_trans(handle, inode, 0);
4613 out:
4614         if (allocated > map->m_len)
4615                 allocated = map->m_len;
4616         ext4_ext_show_leaf(inode, path);
4617         map->m_flags |= EXT4_MAP_MAPPED;
4618         map->m_pblk = newblock;
4619         map->m_len = allocated;
4620 out2:
4621         ext4_ext_drop_refs(path);
4622         kfree(path);
4623
4624         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4625                                        err ? err : allocated);
4626         ext4_es_lru_add(inode);
4627         return err ? err : allocated;
4628 }
4629
4630 void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4631 {
4632         struct super_block *sb = inode->i_sb;
4633         ext4_lblk_t last_block;
4634         int err = 0;
4635
4636         /*
4637          * TODO: optimization is possible here.
4638          * Probably we need not scan at all,
4639          * because page truncation is enough.
4640          */
4641
4642         /* we have to know where to truncate from in crash case */
4643         EXT4_I(inode)->i_disksize = inode->i_size;
4644         ext4_mark_inode_dirty(handle, inode);
4645
4646         last_block = (inode->i_size + sb->s_blocksize - 1)
4647                         >> EXT4_BLOCK_SIZE_BITS(sb);
4648 retry:
4649         err = ext4_es_remove_extent(inode, last_block,
4650                                     EXT_MAX_BLOCKS - last_block);
4651         if (err == -ENOMEM) {
4652                 cond_resched();
4653                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4654                 goto retry;
4655         }
4656         if (err) {
4657                 ext4_std_error(inode->i_sb, err);
4658                 return;
4659         }
4660         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4661         ext4_std_error(inode->i_sb, err);
4662 }
4663
4664 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4665                                   ext4_lblk_t len, loff_t new_size,
4666                                   int flags, int mode)
4667 {
4668         struct inode *inode = file_inode(file);
4669         handle_t *handle;
4670         int ret = 0;
4671         int ret2 = 0;
4672         int retries = 0;
4673         struct ext4_map_blocks map;
4674         unsigned int credits;
4675         loff_t epos;
4676
4677         map.m_lblk = offset;
4678         map.m_len = len;
4679         /*
4680          * Don't normalize the request if it can fit in one extent so
4681          * that it doesn't get unnecessarily split into multiple
4682          * extents.
4683          */
4684         if (len <= EXT_UNWRITTEN_MAX_LEN)
4685                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4686
4687         /*
4688          * credits to insert 1 extent into extent tree
4689          */
4690         credits = ext4_chunk_trans_blocks(inode, len);
4691
4692 retry:
4693         while (ret >= 0 && len) {
4694                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4695                                             credits);
4696                 if (IS_ERR(handle)) {
4697                         ret = PTR_ERR(handle);
4698                         break;
4699                 }
4700                 ret = ext4_map_blocks(handle, inode, &map, flags);
4701                 if (ret <= 0) {
4702                         ext4_debug("inode #%lu: block %u: len %u: "
4703                                    "ext4_ext_map_blocks returned %d",
4704                                    inode->i_ino, map.m_lblk,
4705                                    map.m_len, ret);
4706                         ext4_mark_inode_dirty(handle, inode);
4707                         ret2 = ext4_journal_stop(handle);
4708                         break;
4709                 }
4710                 map.m_lblk += ret;
4711                 map.m_len = len = len - ret;
4712                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4713                 inode->i_ctime = ext4_current_time(inode);
4714                 if (new_size) {
4715                         if (epos > new_size)
4716                                 epos = new_size;
4717                         if (ext4_update_inode_size(inode, epos) & 0x1)
4718                                 inode->i_mtime = inode->i_ctime;
4719                 } else {
4720                         if (epos > inode->i_size)
4721                                 ext4_set_inode_flag(inode,
4722                                                     EXT4_INODE_EOFBLOCKS);
4723                 }
4724                 ext4_mark_inode_dirty(handle, inode);
4725                 ret2 = ext4_journal_stop(handle);
4726                 if (ret2)
4727                         break;
4728         }
4729         if (ret == -ENOSPC &&
4730                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4731                 ret = 0;
4732                 goto retry;
4733         }
4734
4735         return ret > 0 ? ret2 : ret;
4736 }
4737
4738 static long ext4_zero_range(struct file *file, loff_t offset,
4739                             loff_t len, int mode)
4740 {
4741         struct inode *inode = file_inode(file);
4742         handle_t *handle = NULL;
4743         unsigned int max_blocks;
4744         loff_t new_size = 0;
4745         int ret = 0;
4746         int flags;
4747         int credits;
4748         int partial_begin, partial_end;
4749         loff_t start, end;
4750         ext4_lblk_t lblk;
4751         struct address_space *mapping = inode->i_mapping;
4752         unsigned int blkbits = inode->i_blkbits;
4753
4754         trace_ext4_zero_range(inode, offset, len, mode);
4755
4756         if (!S_ISREG(inode->i_mode))
4757                 return -EINVAL;
4758
4759         /* Call ext4_force_commit to flush all data in case of data=journal. */
4760         if (ext4_should_journal_data(inode)) {
4761                 ret = ext4_force_commit(inode->i_sb);
4762                 if (ret)
4763                         return ret;
4764         }
4765
4766         /*
4767          * Write out all dirty pages to avoid race conditions
4768          * Then release them.
4769          */
4770         if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4771                 ret = filemap_write_and_wait_range(mapping, offset,
4772                                                    offset + len - 1);
4773                 if (ret)
4774                         return ret;
4775         }
4776
4777         /*
4778          * Round up offset. This is not fallocate, we neet to zero out
4779          * blocks, so convert interior block aligned part of the range to
4780          * unwritten and possibly manually zero out unaligned parts of the
4781          * range.
4782          */
4783         start = round_up(offset, 1 << blkbits);
4784         end = round_down((offset + len), 1 << blkbits);
4785
4786         if (start < offset || end > offset + len)
4787                 return -EINVAL;
4788         partial_begin = offset & ((1 << blkbits) - 1);
4789         partial_end = (offset + len) & ((1 << blkbits) - 1);
4790
4791         lblk = start >> blkbits;
4792         max_blocks = (end >> blkbits);
4793         if (max_blocks < lblk)
4794                 max_blocks = 0;
4795         else
4796                 max_blocks -= lblk;
4797
4798         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT |
4799                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4800                 EXT4_EX_NOCACHE;
4801         if (mode & FALLOC_FL_KEEP_SIZE)
4802                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4803
4804         mutex_lock(&inode->i_mutex);
4805
4806         /*
4807          * Indirect files do not support unwritten extnets
4808          */
4809         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4810                 ret = -EOPNOTSUPP;
4811                 goto out_mutex;
4812         }
4813
4814         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4815              offset + len > i_size_read(inode)) {
4816                 new_size = offset + len;
4817                 ret = inode_newsize_ok(inode, new_size);
4818                 if (ret)
4819                         goto out_mutex;
4820                 /*
4821                  * If we have a partial block after EOF we have to allocate
4822                  * the entire block.
4823                  */
4824                 if (partial_end)
4825                         max_blocks += 1;
4826         }
4827
4828         if (max_blocks > 0) {
4829
4830                 /* Now release the pages and zero block aligned part of pages*/
4831                 truncate_pagecache_range(inode, start, end - 1);
4832                 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4833
4834                 /* Wait all existing dio workers, newcomers will block on i_mutex */
4835                 ext4_inode_block_unlocked_dio(inode);
4836                 inode_dio_wait(inode);
4837
4838                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4839                                              flags, mode);
4840                 if (ret)
4841                         goto out_dio;
4842                 /*
4843                  * Remove entire range from the extent status tree.
4844                  *
4845                  * ext4_es_remove_extent(inode, lblk, max_blocks) is
4846                  * NOT sufficient.  I'm not sure why this is the case,
4847                  * but let's be conservative and remove the extent
4848                  * status tree for the entire inode.  There should be
4849                  * no outstanding delalloc extents thanks to the
4850                  * filemap_write_and_wait_range() call above.
4851                  */
4852                 ret = ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
4853                 if (ret)
4854                         goto out_dio;
4855         }
4856         if (!partial_begin && !partial_end)
4857                 goto out_dio;
4858
4859         /*
4860          * In worst case we have to writeout two nonadjacent unwritten
4861          * blocks and update the inode
4862          */
4863         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4864         if (ext4_should_journal_data(inode))
4865                 credits += 2;
4866         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4867         if (IS_ERR(handle)) {
4868                 ret = PTR_ERR(handle);
4869                 ext4_std_error(inode->i_sb, ret);
4870                 goto out_dio;
4871         }
4872
4873         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4874         if (new_size) {
4875                 ext4_update_inode_size(inode, new_size);
4876         } else {
4877                 /*
4878                 * Mark that we allocate beyond EOF so the subsequent truncate
4879                 * can proceed even if the new size is the same as i_size.
4880                 */
4881                 if ((offset + len) > i_size_read(inode))
4882                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4883         }
4884         ext4_mark_inode_dirty(handle, inode);
4885
4886         /* Zero out partial block at the edges of the range */
4887         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4888
4889         if (file->f_flags & O_SYNC)
4890                 ext4_handle_sync(handle);
4891
4892         ext4_journal_stop(handle);
4893 out_dio:
4894         ext4_inode_resume_unlocked_dio(inode);
4895 out_mutex:
4896         mutex_unlock(&inode->i_mutex);
4897         return ret;
4898 }
4899
4900 /*
4901  * preallocate space for a file. This implements ext4's fallocate file
4902  * operation, which gets called from sys_fallocate system call.
4903  * For block-mapped files, posix_fallocate should fall back to the method
4904  * of writing zeroes to the required new blocks (the same behavior which is
4905  * expected for file systems which do not support fallocate() system call).
4906  */
4907 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4908 {
4909         struct inode *inode = file_inode(file);
4910         loff_t new_size = 0;
4911         unsigned int max_blocks;
4912         int ret = 0;
4913         int flags;
4914         ext4_lblk_t lblk;
4915         unsigned int blkbits = inode->i_blkbits;
4916
4917         /* Return error if mode is not supported */
4918         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4919                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
4920                 return -EOPNOTSUPP;
4921
4922         if (mode & FALLOC_FL_PUNCH_HOLE)
4923                 return ext4_punch_hole(inode, offset, len);
4924
4925         ret = ext4_convert_inline_data(inode);
4926         if (ret)
4927                 return ret;
4928
4929         /*
4930          * currently supporting (pre)allocate mode for extent-based
4931          * files _only_
4932          */
4933         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4934                 return -EOPNOTSUPP;
4935
4936         if (mode & FALLOC_FL_COLLAPSE_RANGE)
4937                 return ext4_collapse_range(inode, offset, len);
4938
4939         if (mode & FALLOC_FL_ZERO_RANGE)
4940                 return ext4_zero_range(file, offset, len, mode);
4941
4942         trace_ext4_fallocate_enter(inode, offset, len, mode);
4943         lblk = offset >> blkbits;
4944         /*
4945          * We can't just convert len to max_blocks because
4946          * If blocksize = 4096 offset = 3072 and len = 2048
4947          */
4948         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4949                 - lblk;
4950
4951         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4952         if (mode & FALLOC_FL_KEEP_SIZE)
4953                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4954
4955         mutex_lock(&inode->i_mutex);
4956
4957         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4958              offset + len > i_size_read(inode)) {
4959                 new_size = offset + len;
4960                 ret = inode_newsize_ok(inode, new_size);
4961                 if (ret)
4962                         goto out;
4963         }
4964
4965         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4966                                      flags, mode);
4967         if (ret)
4968                 goto out;
4969
4970         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4971                 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
4972                                                 EXT4_I(inode)->i_sync_tid);
4973         }
4974 out:
4975         mutex_unlock(&inode->i_mutex);
4976         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4977         return ret;
4978 }
4979
4980 /*
4981  * This function convert a range of blocks to written extents
4982  * The caller of this function will pass the start offset and the size.
4983  * all unwritten extents within this range will be converted to
4984  * written extents.
4985  *
4986  * This function is called from the direct IO end io call back
4987  * function, to convert the fallocated extents after IO is completed.
4988  * Returns 0 on success.
4989  */
4990 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4991                                    loff_t offset, ssize_t len)
4992 {
4993         unsigned int max_blocks;
4994         int ret = 0;
4995         int ret2 = 0;
4996         struct ext4_map_blocks map;
4997         unsigned int credits, blkbits = inode->i_blkbits;
4998
4999         map.m_lblk = offset >> blkbits;
5000         /*
5001          * We can't just convert len to max_blocks because
5002          * If blocksize = 4096 offset = 3072 and len = 2048
5003          */
5004         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
5005                       map.m_lblk);
5006         /*
5007          * This is somewhat ugly but the idea is clear: When transaction is
5008          * reserved, everything goes into it. Otherwise we rather start several
5009          * smaller transactions for conversion of each extent separately.
5010          */
5011         if (handle) {
5012                 handle = ext4_journal_start_reserved(handle,
5013                                                      EXT4_HT_EXT_CONVERT);
5014                 if (IS_ERR(handle))
5015                         return PTR_ERR(handle);
5016                 credits = 0;
5017         } else {
5018                 /*
5019                  * credits to insert 1 extent into extent tree
5020                  */
5021                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5022         }
5023         while (ret >= 0 && ret < max_blocks) {
5024                 map.m_lblk += ret;
5025                 map.m_len = (max_blocks -= ret);
5026                 if (credits) {
5027                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5028                                                     credits);
5029                         if (IS_ERR(handle)) {
5030                                 ret = PTR_ERR(handle);
5031                                 break;
5032                         }
5033                 }
5034                 ret = ext4_map_blocks(handle, inode, &map,
5035                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5036                 if (ret <= 0)
5037                         ext4_warning(inode->i_sb,
5038                                      "inode #%lu: block %u: len %u: "
5039                                      "ext4_ext_map_blocks returned %d",
5040                                      inode->i_ino, map.m_lblk,
5041                                      map.m_len, ret);
5042                 ext4_mark_inode_dirty(handle, inode);
5043                 if (credits)
5044                         ret2 = ext4_journal_stop(handle);
5045                 if (ret <= 0 || ret2)
5046                         break;
5047         }
5048         if (!credits)
5049                 ret2 = ext4_journal_stop(handle);
5050         return ret > 0 ? ret2 : ret;
5051 }
5052
5053 /*
5054  * If newes is not existing extent (newes->ec_pblk equals zero) find
5055  * delayed extent at start of newes and update newes accordingly and
5056  * return start of the next delayed extent.
5057  *
5058  * If newes is existing extent (newes->ec_pblk is not equal zero)
5059  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5060  * extent found. Leave newes unmodified.
5061  */
5062 static int ext4_find_delayed_extent(struct inode *inode,
5063                                     struct extent_status *newes)
5064 {
5065         struct extent_status es;
5066         ext4_lblk_t block, next_del;
5067
5068         if (newes->es_pblk == 0) {
5069                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5070                                 newes->es_lblk + newes->es_len - 1, &es);
5071
5072                 /*
5073                  * No extent in extent-tree contains block @newes->es_pblk,
5074                  * then the block may stay in 1)a hole or 2)delayed-extent.
5075                  */
5076                 if (es.es_len == 0)
5077                         /* A hole found. */
5078                         return 0;
5079
5080                 if (es.es_lblk > newes->es_lblk) {
5081                         /* A hole found. */
5082                         newes->es_len = min(es.es_lblk - newes->es_lblk,
5083                                             newes->es_len);
5084                         return 0;
5085                 }
5086
5087                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5088         }
5089
5090         block = newes->es_lblk + newes->es_len;
5091         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5092         if (es.es_len == 0)
5093                 next_del = EXT_MAX_BLOCKS;
5094         else
5095                 next_del = es.es_lblk;
5096
5097         return next_del;
5098 }
5099 /* fiemap flags we can handle specified here */
5100 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5101
5102 static int ext4_xattr_fiemap(struct inode *inode,
5103                                 struct fiemap_extent_info *fieinfo)
5104 {
5105         __u64 physical = 0;
5106         __u64 length;
5107         __u32 flags = FIEMAP_EXTENT_LAST;
5108         int blockbits = inode->i_sb->s_blocksize_bits;
5109         int error = 0;
5110
5111         /* in-inode? */
5112         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5113                 struct ext4_iloc iloc;
5114                 int offset;     /* offset of xattr in inode */
5115
5116                 error = ext4_get_inode_loc(inode, &iloc);
5117                 if (error)
5118                         return error;
5119                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5120                 offset = EXT4_GOOD_OLD_INODE_SIZE +
5121                                 EXT4_I(inode)->i_extra_isize;
5122                 physical += offset;
5123                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5124                 flags |= FIEMAP_EXTENT_DATA_INLINE;
5125                 brelse(iloc.bh);
5126         } else { /* external block */
5127                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5128                 length = inode->i_sb->s_blocksize;
5129         }
5130
5131         if (physical)
5132                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5133                                                 length, flags);
5134         return (error < 0 ? error : 0);
5135 }
5136
5137 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5138                 __u64 start, __u64 len)
5139 {
5140         ext4_lblk_t start_blk;
5141         int error = 0;
5142
5143         if (ext4_has_inline_data(inode)) {
5144                 int has_inline = 1;
5145
5146                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline);
5147
5148                 if (has_inline)
5149                         return error;
5150         }
5151
5152         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5153                 error = ext4_ext_precache(inode);
5154                 if (error)
5155                         return error;
5156         }
5157
5158         /* fallback to generic here if not in extents fmt */
5159         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5160                 return generic_block_fiemap(inode, fieinfo, start, len,
5161                         ext4_get_block);
5162
5163         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5164                 return -EBADR;
5165
5166         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5167                 error = ext4_xattr_fiemap(inode, fieinfo);
5168         } else {
5169                 ext4_lblk_t len_blks;
5170                 __u64 last_blk;
5171
5172                 start_blk = start >> inode->i_sb->s_blocksize_bits;
5173                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5174                 if (last_blk >= EXT_MAX_BLOCKS)
5175                         last_blk = EXT_MAX_BLOCKS-1;
5176                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5177
5178                 /*
5179                  * Walk the extent tree gathering extent information
5180                  * and pushing extents back to the user.
5181                  */
5182                 error = ext4_fill_fiemap_extents(inode, start_blk,
5183                                                  len_blks, fieinfo);
5184         }
5185         ext4_es_lru_add(inode);
5186         return error;
5187 }
5188
5189 /*
5190  * ext4_access_path:
5191  * Function to access the path buffer for marking it dirty.
5192  * It also checks if there are sufficient credits left in the journal handle
5193  * to update path.
5194  */
5195 static int
5196 ext4_access_path(handle_t *handle, struct inode *inode,
5197                 struct ext4_ext_path *path)
5198 {
5199         int credits, err;
5200
5201         if (!ext4_handle_valid(handle))
5202                 return 0;
5203
5204         /*
5205          * Check if need to extend journal credits
5206          * 3 for leaf, sb, and inode plus 2 (bmap and group
5207          * descriptor) for each block group; assume two block
5208          * groups
5209          */
5210         if (handle->h_buffer_credits < 7) {
5211                 credits = ext4_writepage_trans_blocks(inode);
5212                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5213                 /* EAGAIN is success */
5214                 if (err && err != -EAGAIN)
5215                         return err;
5216         }
5217
5218         err = ext4_ext_get_access(handle, inode, path);
5219         return err;
5220 }
5221
5222 /*
5223  * ext4_ext_shift_path_extents:
5224  * Shift the extents of a path structure lying between path[depth].p_ext
5225  * and EXT_LAST_EXTENT(path[depth].p_hdr) downwards, by subtracting shift
5226  * from starting block for each extent.
5227  */
5228 static int
5229 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5230                             struct inode *inode, handle_t *handle,
5231                             ext4_lblk_t *start)
5232 {
5233         int depth, err = 0;
5234         struct ext4_extent *ex_start, *ex_last;
5235         bool update = 0;
5236         depth = path->p_depth;
5237
5238         while (depth >= 0) {
5239                 if (depth == path->p_depth) {
5240                         ex_start = path[depth].p_ext;
5241                         if (!ex_start)
5242                                 return -EIO;
5243
5244                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5245                         if (!ex_last)
5246                                 return -EIO;
5247
5248                         err = ext4_access_path(handle, inode, path + depth);
5249                         if (err)
5250                                 goto out;
5251
5252                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5253                                 update = 1;
5254
5255                         *start = le32_to_cpu(ex_last->ee_block) +
5256                                 ext4_ext_get_actual_len(ex_last);
5257
5258                         while (ex_start <= ex_last) {
5259                                 le32_add_cpu(&ex_start->ee_block, -shift);
5260                                 /* Try to merge to the left. */
5261                                 if ((ex_start >
5262                                      EXT_FIRST_EXTENT(path[depth].p_hdr)) &&
5263                                     ext4_ext_try_to_merge_right(inode,
5264                                                         path, ex_start - 1))
5265                                         ex_last--;
5266                                 else
5267                                         ex_start++;
5268                         }
5269                         err = ext4_ext_dirty(handle, inode, path + depth);
5270                         if (err)
5271                                 goto out;
5272
5273                         if (--depth < 0 || !update)
5274                                 break;
5275                 }
5276
5277                 /* Update index too */
5278                 err = ext4_access_path(handle, inode, path + depth);
5279                 if (err)
5280                         goto out;
5281
5282                 le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5283                 err = ext4_ext_dirty(handle, inode, path + depth);
5284                 if (err)
5285                         goto out;
5286
5287                 /* we are done if current index is not a starting index */
5288                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5289                         break;
5290
5291                 depth--;
5292         }
5293
5294 out:
5295         return err;
5296 }
5297
5298 /*
5299  * ext4_ext_shift_extents:
5300  * All the extents which lies in the range from start to the last allocated
5301  * block for the file are shifted downwards by shift blocks.
5302  * On success, 0 is returned, error otherwise.
5303  */
5304 static int
5305 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5306                        ext4_lblk_t start, ext4_lblk_t shift)
5307 {
5308         struct ext4_ext_path *path;
5309         int ret = 0, depth;
5310         struct ext4_extent *extent;
5311         ext4_lblk_t stop_block;
5312         ext4_lblk_t ex_start, ex_end;
5313
5314         /* Let path point to the last extent */
5315         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
5316         if (IS_ERR(path))
5317                 return PTR_ERR(path);
5318
5319         depth = path->p_depth;
5320         extent = path[depth].p_ext;
5321         if (!extent)
5322                 goto out;
5323
5324         stop_block = le32_to_cpu(extent->ee_block) +
5325                         ext4_ext_get_actual_len(extent);
5326
5327         /* Nothing to shift, if hole is at the end of file */
5328         if (start >= stop_block)
5329                 goto out;
5330
5331         /*
5332          * Don't start shifting extents until we make sure the hole is big
5333          * enough to accomodate the shift.
5334          */
5335         path = ext4_find_extent(inode, start - 1, &path, 0);
5336         if (IS_ERR(path))
5337                 return PTR_ERR(path);
5338         depth = path->p_depth;
5339         extent =  path[depth].p_ext;
5340         if (extent) {
5341                 ex_start = le32_to_cpu(extent->ee_block);
5342                 ex_end = le32_to_cpu(extent->ee_block) +
5343                         ext4_ext_get_actual_len(extent);
5344         } else {
5345                 ex_start = 0;
5346                 ex_end = 0;
5347         }
5348
5349         if ((start == ex_start && shift > ex_start) ||
5350             (shift > start - ex_end))
5351                 return -EINVAL;
5352
5353         /* Its safe to start updating extents */
5354         while (start < stop_block) {
5355                 path = ext4_find_extent(inode, start, &path, 0);
5356                 if (IS_ERR(path))
5357                         return PTR_ERR(path);
5358                 depth = path->p_depth;
5359                 extent = path[depth].p_ext;
5360                 if (!extent) {
5361                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5362                                          (unsigned long) start);
5363                         return -EIO;
5364                 }
5365                 if (start > le32_to_cpu(extent->ee_block)) {
5366                         /* Hole, move to the next extent */
5367                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5368                                 path[depth].p_ext++;
5369                         } else {
5370                                 start = ext4_ext_next_allocated_block(path);
5371                                 continue;
5372                         }
5373                 }
5374                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5375                                 handle, &start);
5376                 if (ret)
5377                         break;
5378         }
5379 out:
5380         ext4_ext_drop_refs(path);
5381         kfree(path);
5382         return ret;
5383 }
5384
5385 /*
5386  * ext4_collapse_range:
5387  * This implements the fallocate's collapse range functionality for ext4
5388  * Returns: 0 and non-zero on error.
5389  */
5390 int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5391 {
5392         struct super_block *sb = inode->i_sb;
5393         ext4_lblk_t punch_start, punch_stop;
5394         handle_t *handle;
5395         unsigned int credits;
5396         loff_t new_size, ioffset;
5397         int ret;
5398
5399         /* Collapse range works only on fs block size aligned offsets. */
5400         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5401             len & (EXT4_CLUSTER_SIZE(sb) - 1))
5402                 return -EINVAL;
5403
5404         if (!S_ISREG(inode->i_mode))
5405                 return -EINVAL;
5406
5407         trace_ext4_collapse_range(inode, offset, len);
5408
5409         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5410         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5411
5412         /* Call ext4_force_commit to flush all data in case of data=journal. */
5413         if (ext4_should_journal_data(inode)) {
5414                 ret = ext4_force_commit(inode->i_sb);
5415                 if (ret)
5416                         return ret;
5417         }
5418
5419         /*
5420          * Need to round down offset to be aligned with page size boundary
5421          * for page size > block size.
5422          */
5423         ioffset = round_down(offset, PAGE_SIZE);
5424
5425         /* Write out all dirty pages */
5426         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5427                                            LLONG_MAX);
5428         if (ret)
5429                 return ret;
5430
5431         /* Take mutex lock */
5432         mutex_lock(&inode->i_mutex);
5433
5434         /*
5435          * There is no need to overlap collapse range with EOF, in which case
5436          * it is effectively a truncate operation
5437          */
5438         if (offset + len >= i_size_read(inode)) {
5439                 ret = -EINVAL;
5440                 goto out_mutex;
5441         }
5442
5443         /* Currently just for extent based files */
5444         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5445                 ret = -EOPNOTSUPP;
5446                 goto out_mutex;
5447         }
5448
5449         truncate_pagecache(inode, ioffset);
5450
5451         /* Wait for existing dio to complete */
5452         ext4_inode_block_unlocked_dio(inode);
5453         inode_dio_wait(inode);
5454
5455         credits = ext4_writepage_trans_blocks(inode);
5456         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5457         if (IS_ERR(handle)) {
5458                 ret = PTR_ERR(handle);
5459                 goto out_dio;
5460         }
5461
5462         down_write(&EXT4_I(inode)->i_data_sem);
5463         ext4_discard_preallocations(inode);
5464
5465         ret = ext4_es_remove_extent(inode, punch_start,
5466                                     EXT_MAX_BLOCKS - punch_start);
5467         if (ret) {
5468                 up_write(&EXT4_I(inode)->i_data_sem);
5469                 goto out_stop;
5470         }
5471
5472         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5473         if (ret) {
5474                 up_write(&EXT4_I(inode)->i_data_sem);
5475                 goto out_stop;
5476         }
5477         ext4_discard_preallocations(inode);
5478
5479         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5480                                      punch_stop - punch_start);
5481         if (ret) {
5482                 up_write(&EXT4_I(inode)->i_data_sem);
5483                 goto out_stop;
5484         }
5485
5486         new_size = i_size_read(inode) - len;
5487         i_size_write(inode, new_size);
5488         EXT4_I(inode)->i_disksize = new_size;
5489
5490         up_write(&EXT4_I(inode)->i_data_sem);
5491         if (IS_SYNC(inode))
5492                 ext4_handle_sync(handle);
5493         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5494         ext4_mark_inode_dirty(handle, inode);
5495
5496 out_stop:
5497         ext4_journal_stop(handle);
5498 out_dio:
5499         ext4_inode_resume_unlocked_dio(inode);
5500 out_mutex:
5501         mutex_unlock(&inode->i_mutex);
5502         return ret;
5503 }
5504
5505 /**
5506  * ext4_swap_extents - Swap extents between two inodes
5507  *
5508  * @inode1:     First inode
5509  * @inode2:     Second inode
5510  * @lblk1:      Start block for first inode
5511  * @lblk2:      Start block for second inode
5512  * @count:      Number of blocks to swap
5513  * @mark_unwritten: Mark second inode's extents as unwritten after swap
5514  * @erp:        Pointer to save error value
5515  *
5516  * This helper routine does exactly what is promise "swap extents". All other
5517  * stuff such as page-cache locking consistency, bh mapping consistency or
5518  * extent's data copying must be performed by caller.
5519  * Locking:
5520  *              i_mutex is held for both inodes
5521  *              i_data_sem is locked for write for both inodes
5522  * Assumptions:
5523  *              All pages from requested range are locked for both inodes
5524  */
5525 int
5526 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5527                      struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5528                   ext4_lblk_t count, int unwritten, int *erp)
5529 {
5530         struct ext4_ext_path *path1 = NULL;
5531         struct ext4_ext_path *path2 = NULL;
5532         int replaced_count = 0;
5533
5534         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5535         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5536         BUG_ON(!mutex_is_locked(&inode1->i_mutex));
5537         BUG_ON(!mutex_is_locked(&inode1->i_mutex));
5538
5539         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5540         if (unlikely(*erp))
5541                 return 0;
5542         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5543         if (unlikely(*erp))
5544                 return 0;
5545
5546         while (count) {
5547                 struct ext4_extent *ex1, *ex2, tmp_ex;
5548                 ext4_lblk_t e1_blk, e2_blk;
5549                 int e1_len, e2_len, len;
5550                 int split = 0;
5551
5552                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5553                 if (unlikely(IS_ERR(path1))) {
5554                         *erp = PTR_ERR(path1);
5555                         path1 = NULL;
5556                 finish:
5557                         count = 0;
5558                         goto repeat;
5559                 }
5560                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5561                 if (unlikely(IS_ERR(path2))) {
5562                         *erp = PTR_ERR(path2);
5563                         path2 = NULL;
5564                         goto finish;
5565                 }
5566                 ex1 = path1[path1->p_depth].p_ext;
5567                 ex2 = path2[path2->p_depth].p_ext;
5568                 /* Do we have somthing to swap ? */
5569                 if (unlikely(!ex2 || !ex1))
5570                         goto finish;
5571
5572                 e1_blk = le32_to_cpu(ex1->ee_block);
5573                 e2_blk = le32_to_cpu(ex2->ee_block);
5574                 e1_len = ext4_ext_get_actual_len(ex1);
5575                 e2_len = ext4_ext_get_actual_len(ex2);
5576
5577                 /* Hole handling */
5578                 if (!in_range(lblk1, e1_blk, e1_len) ||
5579                     !in_range(lblk2, e2_blk, e2_len)) {
5580                         ext4_lblk_t next1, next2;
5581
5582                         /* if hole after extent, then go to next extent */
5583                         next1 = ext4_ext_next_allocated_block(path1);
5584                         next2 = ext4_ext_next_allocated_block(path2);
5585                         /* If hole before extent, then shift to that extent */
5586                         if (e1_blk > lblk1)
5587                                 next1 = e1_blk;
5588                         if (e2_blk > lblk2)
5589                                 next2 = e1_blk;
5590                         /* Do we have something to swap */
5591                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5592                                 goto finish;
5593                         /* Move to the rightest boundary */
5594                         len = next1 - lblk1;
5595                         if (len < next2 - lblk2)
5596                                 len = next2 - lblk2;
5597                         if (len > count)
5598                                 len = count;
5599                         lblk1 += len;
5600                         lblk2 += len;
5601                         count -= len;
5602                         goto repeat;
5603                 }
5604
5605                 /* Prepare left boundary */
5606                 if (e1_blk < lblk1) {
5607                         split = 1;
5608                         *erp = ext4_force_split_extent_at(handle, inode1,
5609                                                 &path1, lblk1, 0);
5610                         if (unlikely(*erp))
5611                                 goto finish;
5612                 }
5613                 if (e2_blk < lblk2) {
5614                         split = 1;
5615                         *erp = ext4_force_split_extent_at(handle, inode2,
5616                                                 &path2,  lblk2, 0);
5617                         if (unlikely(*erp))
5618                                 goto finish;
5619                 }
5620                 /* ext4_split_extent_at() may result in leaf extent split,
5621                  * path must to be revalidated. */
5622                 if (split)
5623                         goto repeat;
5624
5625                 /* Prepare right boundary */
5626                 len = count;
5627                 if (len > e1_blk + e1_len - lblk1)
5628                         len = e1_blk + e1_len - lblk1;
5629                 if (len > e2_blk + e2_len - lblk2)
5630                         len = e2_blk + e2_len - lblk2;
5631
5632                 if (len != e1_len) {
5633                         split = 1;
5634                         *erp = ext4_force_split_extent_at(handle, inode1,
5635                                                 &path1, lblk1 + len, 0);
5636                         if (unlikely(*erp))
5637                                 goto finish;
5638                 }
5639                 if (len != e2_len) {
5640                         split = 1;
5641                         *erp = ext4_force_split_extent_at(handle, inode2,
5642                                                 &path2, lblk2 + len, 0);
5643                         if (*erp)
5644                                 goto finish;
5645                 }
5646                 /* ext4_split_extent_at() may result in leaf extent split,
5647                  * path must to be revalidated. */
5648                 if (split)
5649                         goto repeat;
5650
5651                 BUG_ON(e2_len != e1_len);
5652                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5653                 if (unlikely(*erp))
5654                         goto finish;
5655                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5656                 if (unlikely(*erp))
5657                         goto finish;
5658
5659                 /* Both extents are fully inside boundaries. Swap it now */
5660                 tmp_ex = *ex1;
5661                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5662                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5663                 ex1->ee_len = cpu_to_le16(e2_len);
5664                 ex2->ee_len = cpu_to_le16(e1_len);
5665                 if (unwritten)
5666                         ext4_ext_mark_unwritten(ex2);
5667                 if (ext4_ext_is_unwritten(&tmp_ex))
5668                         ext4_ext_mark_unwritten(ex1);
5669
5670                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5671                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5672                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5673                                       path2->p_depth);
5674                 if (unlikely(*erp))
5675                         goto finish;
5676                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5677                                       path1->p_depth);
5678                 /*
5679                  * Looks scarry ah..? second inode already points to new blocks,
5680                  * and it was successfully dirtied. But luckily error may happen
5681                  * only due to journal error, so full transaction will be
5682                  * aborted anyway.
5683                  */
5684                 if (unlikely(*erp))
5685                         goto finish;
5686                 lblk1 += len;
5687                 lblk2 += len;
5688                 replaced_count += len;
5689                 count -= len;
5690
5691         repeat:
5692                 ext4_ext_drop_refs(path1);
5693                 kfree(path1);
5694                 ext4_ext_drop_refs(path2);
5695                 kfree(path2);
5696                 path1 = path2 = NULL;
5697         }
5698         return replaced_count;
5699 }