fs/ext4/extents.c

   1 /*
   2  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3  * Written by Alex Tomas <alex@clusterfs.com>
   4  *
   5  * Architecture independence:
   6  *   Copyright (c) 2005, Bull S.A.
   7  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public Licens
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21  */
  22
  23 /*
  24  * Extents support for EXT4
  25  *
  26  * TODO:
  27  *   - ext4*_error() should be used in some situations
  28  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29  *   - smart tree reduction
  30  */
  31
  32 #include <linux/fs.h>
  33 #include <linux/time.h>
  34 #include <linux/jbd2.h>
  35 #include <linux/highuid.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/quotaops.h>
  38 #include <linux/string.h>
  39 #include <linux/slab.h>
  40 #include <asm/uaccess.h>
  41 #include <linux/fiemap.h>
  42 #include "ext4_jbd2.h"
  43 #include "ext4_extents.h"
  44 #include "xattr.h"
  45
  46 #include <trace/events/ext4.h>
  47
  48 /*
  49  * used by extent splitting.
  50  */
  51 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  52                                         due to ENOSPC */
  53 #define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  54 #define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  55
  56 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  57 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  58
  59 static __le32 ext4_extent_block_csum(struct inode *inode,
  60                                      struct ext4_extent_header *eh)
  61 {
  62         struct ext4_inode_info *ei = EXT4_I(inode);
  63         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  64         __u32 csum;
  65
  66         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  67                            EXT4_EXTENT_TAIL_OFFSET(eh));
  68         return cpu_to_le32(csum);
  69 }
  70
  71 static int ext4_extent_block_csum_verify(struct inode *inode,
  72                                          struct ext4_extent_header *eh)
  73 {
  74         struct ext4_extent_tail *et;
  75
  76         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  77                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  78                 return 1;
  79
  80         et = find_ext4_extent_tail(eh);
  81         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  82                 return 0;
  83         return 1;
  84 }
  85
  86 static void ext4_extent_block_csum_set(struct inode *inode,
  87                                        struct ext4_extent_header *eh)
  88 {
  89         struct ext4_extent_tail *et;
  90
  91         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  92                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  93                 return;
  94
  95         et = find_ext4_extent_tail(eh);
  96         et->et_checksum = ext4_extent_block_csum(inode, eh);
  97 }
  98
  99 static int ext4_split_extent(handle_t *handle,
 100                                 struct inode *inode,
 101                                 struct ext4_ext_path *path,
 102                                 struct ext4_map_blocks *map,
 103                                 int split_flag,
 104                                 int flags);
 105
 106 static int ext4_split_extent_at(handle_t *handle,
 107                              struct inode *inode,
 108                              struct ext4_ext_path *path,
 109                              ext4_lblk_t split,
 110                              int split_flag,
 111                              int flags);
 112
 113 static int ext4_find_delayed_extent(struct inode *inode,
 114                                     struct extent_status *newes);
 115
 116 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 117                                             struct inode *inode,
 118                                             int needed)
 119 {
 120         int err;
 121
 122         if (!ext4_handle_valid(handle))
 123                 return 0;
 124         if (handle->h_buffer_credits > needed)
 125                 return 0;
 126         err = ext4_journal_extend(handle, needed);
 127         if (err <= 0)
 128                 return err;
 129         err = ext4_truncate_restart_trans(handle, inode, needed);
 130         if (err == 0)
 131                 err = -EAGAIN;
 132
 133         return err;
 134 }
 135
 136 /*
 137  * could return:
 138  *  - EROFS
 139  *  - ENOMEM
 140  */
 141 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 142                                 struct ext4_ext_path *path)
 143 {
 144         if (path->p_bh) {
 145                 /* path points to block */
 146                 BUFFER_TRACE(path->p_bh, "get_write_access");
 147                 return ext4_journal_get_write_access(handle, path->p_bh);
 148         }
 149         /* path points to leaf/index in inode body */
 150         /* we use in-core data, no need to protect them */
 151         return 0;
 152 }
 153
 154 /*
 155  * could return:
 156  *  - EROFS
 157  *  - ENOMEM
 158  *  - EIO
 159  */
 160 int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 161                      struct inode *inode, struct ext4_ext_path *path)
 162 {
 163         int err;
 164         if (path->p_bh) {
 165                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 166                 /* path points to block */
 167                 err = __ext4_handle_dirty_metadata(where, line, handle,
 168                                                    inode, path->p_bh);
 169         } else {
 170                 /* path points to leaf/index in inode body */
 171                 err = ext4_mark_inode_dirty(handle, inode);
 172         }
 173         return err;
 174 }
 175
 176 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 177                               struct ext4_ext_path *path,
 178                               ext4_lblk_t block)
 179 {
 180         if (path) {
 181                 int depth = path->p_depth;
 182                 struct ext4_extent *ex;
 183
 184                 /*
 185                  * Try to predict block placement assuming that we are
 186                  * filling in a file which will eventually be
 187                  * non-sparse --- i.e., in the case of libbfd writing
 188                  * an ELF object sections out-of-order but in a way
 189                  * the eventually results in a contiguous object or
 190                  * executable file, or some database extending a table
 191                  * space file.  However, this is actually somewhat
 192                  * non-ideal if we are writing a sparse file such as
 193                  * qemu or KVM writing a raw image file that is going
 194                  * to stay fairly sparse, since it will end up
 195                  * fragmenting the file system's free space.  Maybe we
 196                  * should have some hueristics or some way to allow
 197                  * userspace to pass a hint to file system,
 198                  * especially if the latter case turns out to be
 199                  * common.
 200                  */
 201                 ex = path[depth].p_ext;
 202                 if (ex) {
 203                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 204                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 205
 206                         if (block > ext_block)
 207                                 return ext_pblk + (block - ext_block);
 208                         else
 209                                 return ext_pblk - (ext_block - block);
 210                 }
 211
 212                 /* it looks like index is empty;
 213                  * try to find starting block from index itself */
 214                 if (path[depth].p_bh)
 215                         return path[depth].p_bh->b_blocknr;
 216         }
 217
 218         /* OK. use inode's group */
 219         return ext4_inode_to_goal_block(inode);
 220 }
 221
 222 /*
 223  * Allocation for a meta data block
 224  */
 225 static ext4_fsblk_t
 226 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 227                         struct ext4_ext_path *path,
 228                         struct ext4_extent *ex, int *err, unsigned int flags)
 229 {
 230         ext4_fsblk_t goal, newblock;
 231
 232         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 233         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 234                                         NULL, err);
 235         return newblock;
 236 }
 237
 238 static inline int ext4_ext_space_block(struct inode *inode, int check)
 239 {
 240         int size;
 241
 242         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 243                         / sizeof(struct ext4_extent);
 244 #ifdef AGGRESSIVE_TEST
 245         if (!check && size > 6)
 246                 size = 6;
 247 #endif
 248         return size;
 249 }
 250
 251 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 252 {
 253         int size;
 254
 255         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 256                         / sizeof(struct ext4_extent_idx);
 257 #ifdef AGGRESSIVE_TEST
 258         if (!check && size > 5)
 259                 size = 5;
 260 #endif
 261         return size;
 262 }
 263
 264 static inline int ext4_ext_space_root(struct inode *inode, int check)
 265 {
 266         int size;
 267
 268         size = sizeof(EXT4_I(inode)->i_data);
 269         size -= sizeof(struct ext4_extent_header);
 270         size /= sizeof(struct ext4_extent);
 271 #ifdef AGGRESSIVE_TEST
 272         if (!check && size > 3)
 273                 size = 3;
 274 #endif
 275         return size;
 276 }
 277
 278 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 279 {
 280         int size;
 281
 282         size = sizeof(EXT4_I(inode)->i_data);
 283         size -= sizeof(struct ext4_extent_header);
 284         size /= sizeof(struct ext4_extent_idx);
 285 #ifdef AGGRESSIVE_TEST
 286         if (!check && size > 4)
 287                 size = 4;
 288 #endif
 289         return size;
 290 }
 291
 292 /*
 293  * Calculate the number of metadata blocks needed
 294  * to allocate @blocks
 295  * Worse case is one block per extent
 296  */
 297 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 298 {
 299         struct ext4_inode_info *ei = EXT4_I(inode);
 300         int idxs;
 301
 302         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 303                 / sizeof(struct ext4_extent_idx));
 304
 305         /*
 306          * If the new delayed allocation block is contiguous with the
 307          * previous da block, it can share index blocks with the
 308          * previous block, so we only need to allocate a new index
 309          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 310          * an additional index block, and at ldxs**3 blocks, yet
 311          * another index blocks.
 312          */
 313         if (ei->i_da_metadata_calc_len &&
 314             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 315                 int num = 0;
 316
 317                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 318                         num++;
 319                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 320                         num++;
 321                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 322                         num++;
 323                         ei->i_da_metadata_calc_len = 0;
 324                 } else
 325                         ei->i_da_metadata_calc_len++;
 326                 ei->i_da_metadata_calc_last_lblock++;
 327                 return num;
 328         }
 329
 330         /*
 331          * In the worst case we need a new set of index blocks at
 332          * every level of the inode's extent tree.
 333          */
 334         ei->i_da_metadata_calc_len = 1;
 335         ei->i_da_metadata_calc_last_lblock = lblock;
 336         return ext_depth(inode) + 1;
 337 }
 338
 339 static int
 340 ext4_ext_max_entries(struct inode *inode, int depth)
 341 {
 342         int max;
 343
 344         if (depth == ext_depth(inode)) {
 345                 if (depth == 0)
 346                         max = ext4_ext_space_root(inode, 1);
 347                 else
 348                         max = ext4_ext_space_root_idx(inode, 1);
 349         } else {
 350                 if (depth == 0)
 351                         max = ext4_ext_space_block(inode, 1);
 352                 else
 353                         max = ext4_ext_space_block_idx(inode, 1);
 354         }
 355
 356         return max;
 357 }
 358
 359 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 360 {
 361         ext4_fsblk_t block = ext4_ext_pblock(ext);
 362         int len = ext4_ext_get_actual_len(ext);
 363         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 364         ext4_lblk_t last = lblock + len - 1;
 365
 366         if (lblock > last)
 367                 return 0;
 368         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 369 }
 370
 371 static int ext4_valid_extent_idx(struct inode *inode,
 372                                 struct ext4_extent_idx *ext_idx)
 373 {
 374         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 375
 376         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 377 }
 378
 379 static int ext4_valid_extent_entries(struct inode *inode,
 380                                 struct ext4_extent_header *eh,
 381                                 int depth)
 382 {
 383         unsigned short entries;
 384         if (eh->eh_entries == 0)
 385                 return 1;
 386
 387         entries = le16_to_cpu(eh->eh_entries);
 388
 389         if (depth == 0) {
 390                 /* leaf entries */
 391                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 392                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 393                 ext4_fsblk_t pblock = 0;
 394                 ext4_lblk_t lblock = 0;
 395                 ext4_lblk_t prev = 0;
 396                 int len = 0;
 397                 while (entries) {
 398                         if (!ext4_valid_extent(inode, ext))
 399                                 return 0;
 400
 401                         /* Check for overlapping extents */
 402                         lblock = le32_to_cpu(ext->ee_block);
 403                         len = ext4_ext_get_actual_len(ext);
 404                         if ((lblock <= prev) && prev) {
 405                                 pblock = ext4_ext_pblock(ext);
 406                                 es->s_last_error_block = cpu_to_le64(pblock);
 407                                 return 0;
 408                         }
 409                         ext++;
 410                         entries--;
 411                         prev = lblock + len - 1;
 412                 }
 413         } else {
 414                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 415                 while (entries) {
 416                         if (!ext4_valid_extent_idx(inode, ext_idx))
 417                                 return 0;
 418                         ext_idx++;
 419                         entries--;
 420                 }
 421         }
 422         return 1;
 423 }
 424
 425 static int __ext4_ext_check(const char *function, unsigned int line,
 426                             struct inode *inode, struct ext4_extent_header *eh,
 427                             int depth, ext4_fsblk_t pblk)
 428 {
 429         const char *error_msg;
 430         int max = 0;
 431
 432         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 433                 error_msg = "invalid magic";
 434                 goto corrupted;
 435         }
 436         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 437                 error_msg = "unexpected eh_depth";
 438                 goto corrupted;
 439         }
 440         if (unlikely(eh->eh_max == 0)) {
 441                 error_msg = "invalid eh_max";
 442                 goto corrupted;
 443         }
 444         max = ext4_ext_max_entries(inode, depth);
 445         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 446                 error_msg = "too large eh_max";
 447                 goto corrupted;
 448         }
 449         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 450                 error_msg = "invalid eh_entries";
 451                 goto corrupted;
 452         }
 453         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 454                 error_msg = "invalid extent entries";
 455                 goto corrupted;
 456         }
 457         /* Verify checksum on non-root extent tree nodes */
 458         if (ext_depth(inode) != depth &&
 459             !ext4_extent_block_csum_verify(inode, eh)) {
 460                 error_msg = "extent tree corrupted";
 461                 goto corrupted;
 462         }
 463         return 0;
 464
 465 corrupted:
 466         ext4_error_inode(inode, function, line, 0,
 467                          "pblk %llu bad header/extent: %s - magic %x, "
 468                          "entries %u, max %u(%u), depth %u(%u)",
 469                          (unsigned long long) pblk, error_msg,
 470                          le16_to_cpu(eh->eh_magic),
 471                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 472                          max, le16_to_cpu(eh->eh_depth), depth);
 473         return -EIO;
 474 }
 475
 476 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 477         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 478
 479 int ext4_ext_check_inode(struct inode *inode)
 480 {
 481         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 482 }
 483
 484 static struct buffer_head *
 485 __read_extent_tree_block(const char *function, unsigned int line,
 486                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 487                          int flags)
 488 {
 489         struct buffer_head              *bh;
 490         int                             err;
 491
 492         bh = sb_getblk(inode->i_sb, pblk);
 493         if (unlikely(!bh))
 494                 return ERR_PTR(-ENOMEM);
 495
 496         if (!bh_uptodate_or_lock(bh)) {
 497                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 498                 err = bh_submit_read(bh);
 499                 if (err < 0)
 500                         goto errout;
 501         }
 502         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 503                 return bh;
 504         err = __ext4_ext_check(function, line, inode,
 505                                ext_block_hdr(bh), depth, pblk);
 506         if (err)
 507                 goto errout;
 508         set_buffer_verified(bh);
 509         /*
 510          * If this is a leaf block, cache all of its entries
 511          */
 512         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 513                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 514                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 515                 ext4_lblk_t prev = 0;
 516                 int i;
 517
 518                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 519                         unsigned int status = EXTENT_STATUS_WRITTEN;
 520                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 521                         int len = ext4_ext_get_actual_len(ex);
 522
 523                         if (prev && (prev != lblk))
 524                                 ext4_es_cache_extent(inode, prev,
 525                                                      lblk - prev, ~0,
 526                                                      EXTENT_STATUS_HOLE);
 527
 528                         if (ext4_ext_is_unwritten(ex))
 529                                 status = EXTENT_STATUS_UNWRITTEN;
 530                         ext4_es_cache_extent(inode, lblk, len,
 531                                              ext4_ext_pblock(ex), status);
 532                         prev = lblk + len;
 533                 }
 534         }
 535         return bh;
 536 errout:
 537         put_bh(bh);
 538         return ERR_PTR(err);
 539
 540 }
 541
 542 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 543         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 544                                  (depth), (flags))
 545
 546 /*
 547  * This function is called to cache a file's extent information in the
 548  * extent status tree
 549  */
 550 int ext4_ext_precache(struct inode *inode)
 551 {
 552         struct ext4_inode_info *ei = EXT4_I(inode);
 553         struct ext4_ext_path *path = NULL;
 554         struct buffer_head *bh;
 555         int i = 0, depth, ret = 0;
 556
 557         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 558                 return 0;       /* not an extent-mapped inode */
 559
 560         down_read(&ei->i_data_sem);
 561         depth = ext_depth(inode);
 562
 563         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 564                        GFP_NOFS);
 565         if (path == NULL) {
 566                 up_read(&ei->i_data_sem);
 567                 return -ENOMEM;
 568         }
 569
 570         /* Don't cache anything if there are no external extent blocks */
 571         if (depth == 0)
 572                 goto out;
 573         path[0].p_hdr = ext_inode_hdr(inode);
 574         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 575         if (ret)
 576                 goto out;
 577         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 578         while (i >= 0) {
 579                 /*
 580                  * If this is a leaf block or we've reached the end of
 581                  * the index block, go up
 582                  */
 583                 if ((i == depth) ||
 584                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 585                         brelse(path[i].p_bh);
 586                         path[i].p_bh = NULL;
 587                         i--;
 588                         continue;
 589                 }
 590                 bh = read_extent_tree_block(inode,
 591                                             ext4_idx_pblock(path[i].p_idx++),
 592                                             depth - i - 1,
 593                                             EXT4_EX_FORCE_CACHE);
 594                 if (IS_ERR(bh)) {
 595                         ret = PTR_ERR(bh);
 596                         break;
 597                 }
 598                 i++;
 599                 path[i].p_bh = bh;
 600                 path[i].p_hdr = ext_block_hdr(bh);
 601                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 602         }
 603         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 604 out:
 605         up_read(&ei->i_data_sem);
 606         ext4_ext_drop_refs(path);
 607         kfree(path);
 608         return ret;
 609 }
 610
 611 #ifdef EXT_DEBUG
 612 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 613 {
 614         int k, l = path->p_depth;
 615
 616         ext_debug("path:");
 617         for (k = 0; k <= l; k++, path++) {
 618                 if (path->p_idx) {
 619                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 620                             ext4_idx_pblock(path->p_idx));
 621                 } else if (path->p_ext) {
 622                         ext_debug("  %d:[%d]%d:%llu ",
 623                                   le32_to_cpu(path->p_ext->ee_block),
 624                                   ext4_ext_is_unwritten(path->p_ext),
 625                                   ext4_ext_get_actual_len(path->p_ext),
 626                                   ext4_ext_pblock(path->p_ext));
 627                 } else
 628                         ext_debug("  []");
 629         }
 630         ext_debug("\n");
 631 }
 632
 633 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 634 {
 635         int depth = ext_depth(inode);
 636         struct ext4_extent_header *eh;
 637         struct ext4_extent *ex;
 638         int i;
 639
 640         if (!path)
 641                 return;
 642
 643         eh = path[depth].p_hdr;
 644         ex = EXT_FIRST_EXTENT(eh);
 645
 646         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 647
 648         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 649                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 650                           ext4_ext_is_unwritten(ex),
 651                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 652         }
 653         ext_debug("\n");
 654 }
 655
 656 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 657                         ext4_fsblk_t newblock, int level)
 658 {
 659         int depth = ext_depth(inode);
 660         struct ext4_extent *ex;
 661
 662         if (depth != level) {
 663                 struct ext4_extent_idx *idx;
 664                 idx = path[level].p_idx;
 665                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 666                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 667                                         le32_to_cpu(idx->ei_block),
 668                                         ext4_idx_pblock(idx),
 669                                         newblock);
 670                         idx++;
 671                 }
 672
 673                 return;
 674         }
 675
 676         ex = path[depth].p_ext;
 677         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 678                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 679                                 le32_to_cpu(ex->ee_block),
 680                                 ext4_ext_pblock(ex),
 681                                 ext4_ext_is_unwritten(ex),
 682                                 ext4_ext_get_actual_len(ex),
 683                                 newblock);
 684                 ex++;
 685         }
 686 }
 687
 688 #else
 689 #define ext4_ext_show_path(inode, path)
 690 #define ext4_ext_show_leaf(inode, path)
 691 #define ext4_ext_show_move(inode, path, newblock, level)
 692 #endif
 693
 694 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 695 {
 696         int depth = path->p_depth;
 697         int i;
 698
 699         for (i = 0; i <= depth; i++, path++)
 700                 if (path->p_bh) {
 701                         brelse(path->p_bh);
 702                         path->p_bh = NULL;
 703                 }
 704 }
 705
 706 /*
 707  * ext4_ext_binsearch_idx:
 708  * binary search for the closest index of the given block
 709  * the header must be checked before calling this
 710  */
 711 static void
 712 ext4_ext_binsearch_idx(struct inode *inode,
 713                         struct ext4_ext_path *path, ext4_lblk_t block)
 714 {
 715         struct ext4_extent_header *eh = path->p_hdr;
 716         struct ext4_extent_idx *r, *l, *m;
 717
 718
 719         ext_debug("binsearch for %u(idx):  ", block);
 720
 721         l = EXT_FIRST_INDEX(eh) + 1;
 722         r = EXT_LAST_INDEX(eh);
 723         while (l <= r) {
 724                 m = l + (r - l) / 2;
 725                 if (block < le32_to_cpu(m->ei_block))
 726                         r = m - 1;
 727                 else
 728                         l = m + 1;
 729                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 730                                 m, le32_to_cpu(m->ei_block),
 731                                 r, le32_to_cpu(r->ei_block));
 732         }
 733
 734         path->p_idx = l - 1;
 735         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 736                   ext4_idx_pblock(path->p_idx));
 737
 738 #ifdef CHECK_BINSEARCH
 739         {
 740                 struct ext4_extent_idx *chix, *ix;
 741                 int k;
 742
 743                 chix = ix = EXT_FIRST_INDEX(eh);
 744                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 745                   if (k != 0 &&
 746                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 747                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 748                                        "first=0x%p\n", k,
 749                                        ix, EXT_FIRST_INDEX(eh));
 750                                 printk(KERN_DEBUG "%u <= %u\n",
 751                                        le32_to_cpu(ix->ei_block),
 752                                        le32_to_cpu(ix[-1].ei_block));
 753                         }
 754                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 755                                            <= le32_to_cpu(ix[-1].ei_block));
 756                         if (block < le32_to_cpu(ix->ei_block))
 757                                 break;
 758                         chix = ix;
 759                 }
 760                 BUG_ON(chix != path->p_idx);
 761         }
 762 #endif
 763
 764 }
 765
 766 /*
 767  * ext4_ext_binsearch:
 768  * binary search for closest extent of the given block
 769  * the header must be checked before calling this
 770  */
 771 static void
 772 ext4_ext_binsearch(struct inode *inode,
 773                 struct ext4_ext_path *path, ext4_lblk_t block)
 774 {
 775         struct ext4_extent_header *eh = path->p_hdr;
 776         struct ext4_extent *r, *l, *m;
 777
 778         if (eh->eh_entries == 0) {
 779                 /*
 780                  * this leaf is empty:
 781                  * we get such a leaf in split/add case
 782                  */
 783                 return;
 784         }
 785
 786         ext_debug("binsearch for %u:  ", block);
 787
 788         l = EXT_FIRST_EXTENT(eh) + 1;
 789         r = EXT_LAST_EXTENT(eh);
 790
 791         while (l <= r) {
 792                 m = l + (r - l) / 2;
 793                 if (block < le32_to_cpu(m->ee_block))
 794                         r = m - 1;
 795                 else
 796                         l = m + 1;
 797                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 798                                 m, le32_to_cpu(m->ee_block),
 799                                 r, le32_to_cpu(r->ee_block));
 800         }
 801
 802         path->p_ext = l - 1;
 803         ext_debug("  -> %d:%llu:[%d]%d ",
 804                         le32_to_cpu(path->p_ext->ee_block),
 805                         ext4_ext_pblock(path->p_ext),
 806                         ext4_ext_is_unwritten(path->p_ext),
 807                         ext4_ext_get_actual_len(path->p_ext));
 808
 809 #ifdef CHECK_BINSEARCH
 810         {
 811                 struct ext4_extent *chex, *ex;
 812                 int k;
 813
 814                 chex = ex = EXT_FIRST_EXTENT(eh);
 815                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 816                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 817                                           <= le32_to_cpu(ex[-1].ee_block));
 818                         if (block < le32_to_cpu(ex->ee_block))
 819                                 break;
 820                         chex = ex;
 821                 }
 822                 BUG_ON(chex != path->p_ext);
 823         }
 824 #endif
 825
 826 }
 827
 828 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 829 {
 830         struct ext4_extent_header *eh;
 831
 832         eh = ext_inode_hdr(inode);
 833         eh->eh_depth = 0;
 834         eh->eh_entries = 0;
 835         eh->eh_magic = EXT4_EXT_MAGIC;
 836         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 837         ext4_mark_inode_dirty(handle, inode);
 838         return 0;
 839 }
 840
 841 struct ext4_ext_path *
 842 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 843                      struct ext4_ext_path *path, int flags)
 844 {
 845         struct ext4_extent_header *eh;
 846         struct buffer_head *bh;
 847         short int depth, i, ppos = 0, alloc = 0;
 848         int ret;
 849
 850         eh = ext_inode_hdr(inode);
 851         depth = ext_depth(inode);
 852
 853         /* account possible depth increase */
 854         if (!path) {
 855                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 856                                 GFP_NOFS);
 857                 if (!path)
 858                         return ERR_PTR(-ENOMEM);
 859                 alloc = 1;
 860         }
 861         path[0].p_hdr = eh;
 862         path[0].p_bh = NULL;
 863
 864         i = depth;
 865         /* walk through the tree */
 866         while (i) {
 867                 ext_debug("depth %d: num %d, max %d\n",
 868                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 869
 870                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 871                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 872                 path[ppos].p_depth = i;
 873                 path[ppos].p_ext = NULL;
 874
 875                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 876                                             flags);
 877                 if (IS_ERR(bh)) {
 878                         ret = PTR_ERR(bh);
 879                         goto err;
 880                 }
 881
 882                 eh = ext_block_hdr(bh);
 883                 ppos++;
 884                 if (unlikely(ppos > depth)) {
 885                         put_bh(bh);
 886                         EXT4_ERROR_INODE(inode,
 887                                          "ppos %d > depth %d", ppos, depth);
 888                         ret = -EIO;
 889                         goto err;
 890                 }
 891                 path[ppos].p_bh = bh;
 892                 path[ppos].p_hdr = eh;
 893         }
 894
 895         path[ppos].p_depth = i;
 896         path[ppos].p_ext = NULL;
 897         path[ppos].p_idx = NULL;
 898
 899         /* find extent */
 900         ext4_ext_binsearch(inode, path + ppos, block);
 901         /* if not an empty leaf */
 902         if (path[ppos].p_ext)
 903                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 904
 905         ext4_ext_show_path(inode, path);
 906
 907         return path;
 908
 909 err:
 910         ext4_ext_drop_refs(path);
 911         if (alloc)
 912                 kfree(path);
 913         return ERR_PTR(ret);
 914 }
 915
 916 /*
 917  * ext4_ext_insert_index:
 918  * insert new index [@logical;@ptr] into the block at @curp;
 919  * check where to insert: before @curp or after @curp
 920  */
 921 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 922                                  struct ext4_ext_path *curp,
 923                                  int logical, ext4_fsblk_t ptr)
 924 {
 925         struct ext4_extent_idx *ix;
 926         int len, err;
 927
 928         err = ext4_ext_get_access(handle, inode, curp);
 929         if (err)
 930                 return err;
 931
 932         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 933                 EXT4_ERROR_INODE(inode,
 934                                  "logical %d == ei_block %d!",
 935                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 936                 return -EIO;
 937         }
 938
 939         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 940                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 941                 EXT4_ERROR_INODE(inode,
 942                                  "eh_entries %d >= eh_max %d!",
 943                                  le16_to_cpu(curp->p_hdr->eh_entries),
 944                                  le16_to_cpu(curp->p_hdr->eh_max));
 945                 return -EIO;
 946         }
 947
 948         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 949                 /* insert after */
 950                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 951                 ix = curp->p_idx + 1;
 952         } else {
 953                 /* insert before */
 954                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 955                 ix = curp->p_idx;
 956         }
 957
 958         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 959         BUG_ON(len < 0);
 960         if (len > 0) {
 961                 ext_debug("insert new index %d: "
 962                                 "move %d indices from 0x%p to 0x%p\n",
 963                                 logical, len, ix, ix + 1);
 964                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 965         }
 966
 967         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 968                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 969                 return -EIO;
 970         }
 971
 972         ix->ei_block = cpu_to_le32(logical);
 973         ext4_idx_store_pblock(ix, ptr);
 974         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 975
 976         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 977                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 978                 return -EIO;
 979         }
 980
 981         err = ext4_ext_dirty(handle, inode, curp);
 982         ext4_std_error(inode->i_sb, err);
 983
 984         return err;
 985 }
 986
 987 /*
 988  * ext4_ext_split:
 989  * inserts new subtree into the path, using free index entry
 990  * at depth @at:
 991  * - allocates all needed blocks (new leaf and all intermediate index blocks)
 992  * - makes decision where to split
 993  * - moves remaining extents and index entries (right to the split point)
 994  *   into the newly allocated blocks
 995  * - initializes subtree
 996  */
 997 static int ext4_ext_split(handle_t *handle, struct inode *inode,
 998                           unsigned int flags,
 999                           struct ext4_ext_path *path,
1000                           struct ext4_extent *newext, int at)
1001 {
1002         struct buffer_head *bh = NULL;
1003         int depth = ext_depth(inode);
1004         struct ext4_extent_header *neh;
1005         struct ext4_extent_idx *fidx;
1006         int i = at, k, m, a;
1007         ext4_fsblk_t newblock, oldblock;
1008         __le32 border;
1009         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1010         int err = 0;
1011
1012         /* make decision: where to split? */
1013         /* FIXME: now decision is simplest: at current extent */
1014
1015         /* if current leaf will be split, then we should use
1016          * border from split point */
1017         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1018                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1019                 return -EIO;
1020         }
1021         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1022                 border = path[depth].p_ext[1].ee_block;
1023                 ext_debug("leaf will be split."
1024                                 " next leaf starts at %d\n",
1025                                   le32_to_cpu(border));
1026         } else {
1027                 border = newext->ee_block;
1028                 ext_debug("leaf will be added."
1029                                 " next leaf starts at %d\n",
1030                                 le32_to_cpu(border));
1031         }
1032
1033         /*
1034          * If error occurs, then we break processing
1035          * and mark filesystem read-only. index won't
1036          * be inserted and tree will be in consistent
1037          * state. Next mount will repair buffers too.
1038          */
1039
1040         /*
1041          * Get array to track all allocated blocks.
1042          * We need this to handle errors and free blocks
1043          * upon them.
1044          */
1045         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1046         if (!ablocks)
1047                 return -ENOMEM;
1048
1049         /* allocate all needed blocks */
1050         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1051         for (a = 0; a < depth - at; a++) {
1052                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1053                                                    newext, &err, flags);
1054                 if (newblock == 0)
1055                         goto cleanup;
1056                 ablocks[a] = newblock;
1057         }
1058
1059         /* initialize new leaf */
1060         newblock = ablocks[--a];
1061         if (unlikely(newblock == 0)) {
1062                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1063                 err = -EIO;
1064                 goto cleanup;
1065         }
1066         bh = sb_getblk(inode->i_sb, newblock);
1067         if (unlikely(!bh)) {
1068                 err = -ENOMEM;
1069                 goto cleanup;
1070         }
1071         lock_buffer(bh);
1072
1073         err = ext4_journal_get_create_access(handle, bh);
1074         if (err)
1075                 goto cleanup;
1076
1077         neh = ext_block_hdr(bh);
1078         neh->eh_entries = 0;
1079         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1080         neh->eh_magic = EXT4_EXT_MAGIC;
1081         neh->eh_depth = 0;
1082
1083         /* move remainder of path[depth] to the new leaf */
1084         if (unlikely(path[depth].p_hdr->eh_entries !=
1085                      path[depth].p_hdr->eh_max)) {
1086                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1087                                  path[depth].p_hdr->eh_entries,
1088                                  path[depth].p_hdr->eh_max);
1089                 err = -EIO;
1090                 goto cleanup;
1091         }
1092         /* start copy from next extent */
1093         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1094         ext4_ext_show_move(inode, path, newblock, depth);
1095         if (m) {
1096                 struct ext4_extent *ex;
1097                 ex = EXT_FIRST_EXTENT(neh);
1098                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1099                 le16_add_cpu(&neh->eh_entries, m);
1100         }
1101
1102         ext4_extent_block_csum_set(inode, neh);
1103         set_buffer_uptodate(bh);
1104         unlock_buffer(bh);
1105
1106         err = ext4_handle_dirty_metadata(handle, inode, bh);
1107         if (err)
1108                 goto cleanup;
1109         brelse(bh);
1110         bh = NULL;
1111
1112         /* correct old leaf */
1113         if (m) {
1114                 err = ext4_ext_get_access(handle, inode, path + depth);
1115                 if (err)
1116                         goto cleanup;
1117                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1118                 err = ext4_ext_dirty(handle, inode, path + depth);
1119                 if (err)
1120                         goto cleanup;
1121
1122         }
1123
1124         /* create intermediate indexes */
1125         k = depth - at - 1;
1126         if (unlikely(k < 0)) {
1127                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1128                 err = -EIO;
1129                 goto cleanup;
1130         }
1131         if (k)
1132                 ext_debug("create %d intermediate indices\n", k);
1133         /* insert new index into current index block */
1134         /* current depth stored in i var */
1135         i = depth - 1;
1136         while (k--) {
1137                 oldblock = newblock;
1138                 newblock = ablocks[--a];
1139                 bh = sb_getblk(inode->i_sb, newblock);
1140                 if (unlikely(!bh)) {
1141                         err = -ENOMEM;
1142                         goto cleanup;
1143                 }
1144                 lock_buffer(bh);
1145
1146                 err = ext4_journal_get_create_access(handle, bh);
1147                 if (err)
1148                         goto cleanup;
1149
1150                 neh = ext_block_hdr(bh);
1151                 neh->eh_entries = cpu_to_le16(1);
1152                 neh->eh_magic = EXT4_EXT_MAGIC;
1153                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1154                 neh->eh_depth = cpu_to_le16(depth - i);
1155                 fidx = EXT_FIRST_INDEX(neh);
1156                 fidx->ei_block = border;
1157                 ext4_idx_store_pblock(fidx, oldblock);
1158
1159                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1160                                 i, newblock, le32_to_cpu(border), oldblock);
1161
1162                 /* move remainder of path[i] to the new index block */
1163                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1164                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1165                         EXT4_ERROR_INODE(inode,
1166                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1167                                          le32_to_cpu(path[i].p_ext->ee_block));
1168                         err = -EIO;
1169                         goto cleanup;
1170                 }
1171                 /* start copy indexes */
1172                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1173                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1174                                 EXT_MAX_INDEX(path[i].p_hdr));
1175                 ext4_ext_show_move(inode, path, newblock, i);
1176                 if (m) {
1177                         memmove(++fidx, path[i].p_idx,
1178                                 sizeof(struct ext4_extent_idx) * m);
1179                         le16_add_cpu(&neh->eh_entries, m);
1180                 }
1181                 ext4_extent_block_csum_set(inode, neh);
1182                 set_buffer_uptodate(bh);
1183                 unlock_buffer(bh);
1184
1185                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1186                 if (err)
1187                         goto cleanup;
1188                 brelse(bh);
1189                 bh = NULL;
1190
1191                 /* correct old index */
1192                 if (m) {
1193                         err = ext4_ext_get_access(handle, inode, path + i);
1194                         if (err)
1195                                 goto cleanup;
1196                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1197                         err = ext4_ext_dirty(handle, inode, path + i);
1198                         if (err)
1199                                 goto cleanup;
1200                 }
1201
1202                 i--;
1203         }
1204
1205         /* insert new index */
1206         err = ext4_ext_insert_index(handle, inode, path + at,
1207                                     le32_to_cpu(border), newblock);
1208
1209 cleanup:
1210         if (bh) {
1211                 if (buffer_locked(bh))
1212                         unlock_buffer(bh);
1213                 brelse(bh);
1214         }
1215
1216         if (err) {
1217                 /* free all allocated blocks in error case */
1218                 for (i = 0; i < depth; i++) {
1219                         if (!ablocks[i])
1220                                 continue;
1221                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1222                                          EXT4_FREE_BLOCKS_METADATA);
1223                 }
1224         }
1225         kfree(ablocks);
1226
1227         return err;
1228 }
1229
1230 /*
1231  * ext4_ext_grow_indepth:
1232  * implements tree growing procedure:
1233  * - allocates new block
1234  * - moves top-level data (index block or leaf) into the new block
1235  * - initializes new top-level, creating index that points to the
1236  *   just created block
1237  */
1238 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1239                                  unsigned int flags,
1240                                  struct ext4_extent *newext)
1241 {
1242         struct ext4_extent_header *neh;
1243         struct buffer_head *bh;
1244         ext4_fsblk_t newblock;
1245         int err = 0;
1246
1247         newblock = ext4_ext_new_meta_block(handle, inode, NULL,
1248                 newext, &err, flags);
1249         if (newblock == 0)
1250                 return err;
1251
1252         bh = sb_getblk(inode->i_sb, newblock);
1253         if (unlikely(!bh))
1254                 return -ENOMEM;
1255         lock_buffer(bh);
1256
1257         err = ext4_journal_get_create_access(handle, bh);
1258         if (err) {
1259                 unlock_buffer(bh);
1260                 goto out;
1261         }
1262
1263         /* move top-level index/leaf into new block */
1264         memmove(bh->b_data, EXT4_I(inode)->i_data,
1265                 sizeof(EXT4_I(inode)->i_data));
1266
1267         /* set size of new block */
1268         neh = ext_block_hdr(bh);
1269         /* old root could have indexes or leaves
1270          * so calculate e_max right way */
1271         if (ext_depth(inode))
1272                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1273         else
1274                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1275         neh->eh_magic = EXT4_EXT_MAGIC;
1276         ext4_extent_block_csum_set(inode, neh);
1277         set_buffer_uptodate(bh);
1278         unlock_buffer(bh);
1279
1280         err = ext4_handle_dirty_metadata(handle, inode, bh);
1281         if (err)
1282                 goto out;
1283
1284         /* Update top-level index: num,max,pointer */
1285         neh = ext_inode_hdr(inode);
1286         neh->eh_entries = cpu_to_le16(1);
1287         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1288         if (neh->eh_depth == 0) {
1289                 /* Root extent block becomes index block */
1290                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1291                 EXT_FIRST_INDEX(neh)->ei_block =
1292                         EXT_FIRST_EXTENT(neh)->ee_block;
1293         }
1294         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1295                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1296                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1297                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1298
1299         le16_add_cpu(&neh->eh_depth, 1);
1300         ext4_mark_inode_dirty(handle, inode);
1301 out:
1302         brelse(bh);
1303
1304         return err;
1305 }
1306
1307 /*
1308  * ext4_ext_create_new_leaf:
1309  * finds empty index and adds new leaf.
1310  * if no free index is found, then it requests in-depth growing.
1311  */
1312 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1313                                     unsigned int mb_flags,
1314                                     unsigned int gb_flags,
1315                                     struct ext4_ext_path *path,
1316                                     struct ext4_extent *newext)
1317 {
1318         struct ext4_ext_path *curp;
1319         int depth, i, err = 0;
1320
1321 repeat:
1322         i = depth = ext_depth(inode);
1323
1324         /* walk up to the tree and look for free index entry */
1325         curp = path + depth;
1326         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1327                 i--;
1328                 curp--;
1329         }
1330
1331         /* we use already allocated block for index block,
1332          * so subsequent data blocks should be contiguous */
1333         if (EXT_HAS_FREE_INDEX(curp)) {
1334                 /* if we found index with free entry, then use that
1335                  * entry: create all needed subtree and add new leaf */
1336                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1337                 if (err)
1338                         goto out;
1339
1340                 /* refill path */
1341                 ext4_ext_drop_refs(path);
1342                 path = ext4_ext_find_extent(inode,
1343                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1344                                     path, gb_flags);
1345                 if (IS_ERR(path))
1346                         err = PTR_ERR(path);
1347         } else {
1348                 /* tree is full, time to grow in depth */
1349                 err = ext4_ext_grow_indepth(handle, inode, mb_flags, newext);
1350                 if (err)
1351                         goto out;
1352
1353                 /* refill path */
1354                 ext4_ext_drop_refs(path);
1355                 path = ext4_ext_find_extent(inode,
1356                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1357                                     path, gb_flags);
1358                 if (IS_ERR(path)) {
1359                         err = PTR_ERR(path);
1360                         goto out;
1361                 }
1362
1363                 /*
1364                  * only first (depth 0 -> 1) produces free space;
1365                  * in all other cases we have to split the grown tree
1366                  */
1367                 depth = ext_depth(inode);
1368                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1369                         /* now we need to split */
1370                         goto repeat;
1371                 }
1372         }
1373
1374 out:
1375         return err;
1376 }
1377
1378 /*
1379  * search the closest allocated block to the left for *logical
1380  * and returns it at @logical + it's physical address at @phys
1381  * if *logical is the smallest allocated block, the function
1382  * returns 0 at @phys
1383  * return value contains 0 (success) or error code
1384  */
1385 static int ext4_ext_search_left(struct inode *inode,
1386                                 struct ext4_ext_path *path,
1387                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1388 {
1389         struct ext4_extent_idx *ix;
1390         struct ext4_extent *ex;
1391         int depth, ee_len;
1392
1393         if (unlikely(path == NULL)) {
1394                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1395                 return -EIO;
1396         }
1397         depth = path->p_depth;
1398         *phys = 0;
1399
1400         if (depth == 0 && path->p_ext == NULL)
1401                 return 0;
1402
1403         /* usually extent in the path covers blocks smaller
1404          * then *logical, but it can be that extent is the
1405          * first one in the file */
1406
1407         ex = path[depth].p_ext;
1408         ee_len = ext4_ext_get_actual_len(ex);
1409         if (*logical < le32_to_cpu(ex->ee_block)) {
1410                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1411                         EXT4_ERROR_INODE(inode,
1412                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1413                                          *logical, le32_to_cpu(ex->ee_block));
1414                         return -EIO;
1415                 }
1416                 while (--depth >= 0) {
1417                         ix = path[depth].p_idx;
1418                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1419                                 EXT4_ERROR_INODE(inode,
1420                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1421                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1422                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1423                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1424                                   depth);
1425                                 return -EIO;
1426                         }
1427                 }
1428                 return 0;
1429         }
1430
1431         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1432                 EXT4_ERROR_INODE(inode,
1433                                  "logical %d < ee_block %d + ee_len %d!",
1434                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1435                 return -EIO;
1436         }
1437
1438         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1439         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1440         return 0;
1441 }
1442
1443 /*
1444  * search the closest allocated block to the right for *logical
1445  * and returns it at @logical + it's physical address at @phys
1446  * if *logical is the largest allocated block, the function
1447  * returns 0 at @phys
1448  * return value contains 0 (success) or error code
1449  */
1450 static int ext4_ext_search_right(struct inode *inode,
1451                                  struct ext4_ext_path *path,
1452                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1453                                  struct ext4_extent **ret_ex)
1454 {
1455         struct buffer_head *bh = NULL;
1456         struct ext4_extent_header *eh;
1457         struct ext4_extent_idx *ix;
1458         struct ext4_extent *ex;
1459         ext4_fsblk_t block;
1460         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1461         int ee_len;
1462
1463         if (unlikely(path == NULL)) {
1464                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1465                 return -EIO;
1466         }
1467         depth = path->p_depth;
1468         *phys = 0;
1469
1470         if (depth == 0 && path->p_ext == NULL)
1471                 return 0;
1472
1473         /* usually extent in the path covers blocks smaller
1474          * then *logical, but it can be that extent is the
1475          * first one in the file */
1476
1477         ex = path[depth].p_ext;
1478         ee_len = ext4_ext_get_actual_len(ex);
1479         if (*logical < le32_to_cpu(ex->ee_block)) {
1480                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1481                         EXT4_ERROR_INODE(inode,
1482                                          "first_extent(path[%d].p_hdr) != ex",
1483                                          depth);
1484                         return -EIO;
1485                 }
1486                 while (--depth >= 0) {
1487                         ix = path[depth].p_idx;
1488                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1489                                 EXT4_ERROR_INODE(inode,
1490                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1491                                                  *logical);
1492                                 return -EIO;
1493                         }
1494                 }
1495                 goto found_extent;
1496         }
1497
1498         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1499                 EXT4_ERROR_INODE(inode,
1500                                  "logical %d < ee_block %d + ee_len %d!",
1501                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1502                 return -EIO;
1503         }
1504
1505         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1506                 /* next allocated block in this leaf */
1507                 ex++;
1508                 goto found_extent;
1509         }
1510
1511         /* go up and search for index to the right */
1512         while (--depth >= 0) {
1513                 ix = path[depth].p_idx;
1514                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1515                         goto got_index;
1516         }
1517
1518         /* we've gone up to the root and found no index to the right */
1519         return 0;
1520
1521 got_index:
1522         /* we've found index to the right, let's
1523          * follow it and find the closest allocated
1524          * block to the right */
1525         ix++;
1526         block = ext4_idx_pblock(ix);
1527         while (++depth < path->p_depth) {
1528                 /* subtract from p_depth to get proper eh_depth */
1529                 bh = read_extent_tree_block(inode, block,
1530                                             path->p_depth - depth, 0);
1531                 if (IS_ERR(bh))
1532                         return PTR_ERR(bh);
1533                 eh = ext_block_hdr(bh);
1534                 ix = EXT_FIRST_INDEX(eh);
1535                 block = ext4_idx_pblock(ix);
1536                 put_bh(bh);
1537         }
1538
1539         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1540         if (IS_ERR(bh))
1541                 return PTR_ERR(bh);
1542         eh = ext_block_hdr(bh);
1543         ex = EXT_FIRST_EXTENT(eh);
1544 found_extent:
1545         *logical = le32_to_cpu(ex->ee_block);
1546         *phys = ext4_ext_pblock(ex);
1547         *ret_ex = ex;
1548         if (bh)
1549                 put_bh(bh);
1550         return 0;
1551 }
1552
1553 /*
1554  * ext4_ext_next_allocated_block:
1555  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1556  * NOTE: it considers block number from index entry as
1557  * allocated block. Thus, index entries have to be consistent
1558  * with leaves.
1559  */
1560 static ext4_lblk_t
1561 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1562 {
1563         int depth;
1564
1565         BUG_ON(path == NULL);
1566         depth = path->p_depth;
1567
1568         if (depth == 0 && path->p_ext == NULL)
1569                 return EXT_MAX_BLOCKS;
1570
1571         while (depth >= 0) {
1572                 if (depth == path->p_depth) {
1573                         /* leaf */
1574                         if (path[depth].p_ext &&
1575                                 path[depth].p_ext !=
1576                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1577                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1578                 } else {
1579                         /* index */
1580                         if (path[depth].p_idx !=
1581                                         EXT_LAST_INDEX(path[depth].p_hdr))
1582                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1583                 }
1584                 depth--;
1585         }
1586
1587         return EXT_MAX_BLOCKS;
1588 }
1589
1590 /*
1591  * ext4_ext_next_leaf_block:
1592  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1593  */
1594 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1595 {
1596         int depth;
1597
1598         BUG_ON(path == NULL);
1599         depth = path->p_depth;
1600
1601         /* zero-tree has no leaf blocks at all */
1602         if (depth == 0)
1603                 return EXT_MAX_BLOCKS;
1604
1605         /* go to index block */
1606         depth--;
1607
1608         while (depth >= 0) {
1609                 if (path[depth].p_idx !=
1610                                 EXT_LAST_INDEX(path[depth].p_hdr))
1611                         return (ext4_lblk_t)
1612                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1613                 depth--;
1614         }
1615
1616         return EXT_MAX_BLOCKS;
1617 }
1618
1619 /*
1620  * ext4_ext_correct_indexes:
1621  * if leaf gets modified and modified extent is first in the leaf,
1622  * then we have to correct all indexes above.
1623  * TODO: do we need to correct tree in all cases?
1624  */
1625 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1626                                 struct ext4_ext_path *path)
1627 {
1628         struct ext4_extent_header *eh;
1629         int depth = ext_depth(inode);
1630         struct ext4_extent *ex;
1631         __le32 border;
1632         int k, err = 0;
1633
1634         eh = path[depth].p_hdr;
1635         ex = path[depth].p_ext;
1636
1637         if (unlikely(ex == NULL || eh == NULL)) {
1638                 EXT4_ERROR_INODE(inode,
1639                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1640                 return -EIO;
1641         }
1642
1643         if (depth == 0) {
1644                 /* there is no tree at all */
1645                 return 0;
1646         }
1647
1648         if (ex != EXT_FIRST_EXTENT(eh)) {
1649                 /* we correct tree if first leaf got modified only */
1650                 return 0;
1651         }
1652
1653         /*
1654          * TODO: we need correction if border is smaller than current one
1655          */
1656         k = depth - 1;
1657         border = path[depth].p_ext->ee_block;
1658         err = ext4_ext_get_access(handle, inode, path + k);
1659         if (err)
1660                 return err;
1661         path[k].p_idx->ei_block = border;
1662         err = ext4_ext_dirty(handle, inode, path + k);
1663         if (err)
1664                 return err;
1665
1666         while (k--) {
1667                 /* change all left-side indexes */
1668                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1669                         break;
1670                 err = ext4_ext_get_access(handle, inode, path + k);
1671                 if (err)
1672                         break;
1673                 path[k].p_idx->ei_block = border;
1674                 err = ext4_ext_dirty(handle, inode, path + k);
1675                 if (err)
1676                         break;
1677         }
1678
1679         return err;
1680 }
1681
1682 int
1683 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1684                                 struct ext4_extent *ex2)
1685 {
1686         unsigned short ext1_ee_len, ext2_ee_len;
1687
1688         /*
1689          * Make sure that both extents are initialized. We don't merge
1690          * unwritten extents so that we can be sure that end_io code has
1691          * the extent that was written properly split out and conversion to
1692          * initialized is trivial.
1693          */
1694         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1695                 return 0;
1696
1697         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1698         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1699
1700         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1701                         le32_to_cpu(ex2->ee_block))
1702                 return 0;
1703
1704         /*
1705          * To allow future support for preallocated extents to be added
1706          * as an RO_COMPAT feature, refuse to merge to extents if
1707          * this can result in the top bit of ee_len being set.
1708          */
1709         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1710                 return 0;
1711         if (ext4_ext_is_unwritten(ex1) &&
1712             (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1713              atomic_read(&EXT4_I(inode)->i_unwritten) ||
1714              (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1715                 return 0;
1716 #ifdef AGGRESSIVE_TEST
1717         if (ext1_ee_len >= 4)
1718                 return 0;
1719 #endif
1720
1721         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1722                 return 1;
1723         return 0;
1724 }
1725
1726 /*
1727  * This function tries to merge the "ex" extent to the next extent in the tree.
1728  * It always tries to merge towards right. If you want to merge towards
1729  * left, pass "ex - 1" as argument instead of "ex".
1730  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1731  * 1 if they got merged.
1732  */
1733 static int ext4_ext_try_to_merge_right(struct inode *inode,
1734                                  struct ext4_ext_path *path,
1735                                  struct ext4_extent *ex)
1736 {
1737         struct ext4_extent_header *eh;
1738         unsigned int depth, len;
1739         int merge_done = 0, unwritten;
1740
1741         depth = ext_depth(inode);
1742         BUG_ON(path[depth].p_hdr == NULL);
1743         eh = path[depth].p_hdr;
1744
1745         while (ex < EXT_LAST_EXTENT(eh)) {
1746                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1747                         break;
1748                 /* merge with next extent! */
1749                 unwritten = ext4_ext_is_unwritten(ex);
1750                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1751                                 + ext4_ext_get_actual_len(ex + 1));
1752                 if (unwritten)
1753                         ext4_ext_mark_unwritten(ex);
1754
1755                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1756                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1757                                 * sizeof(struct ext4_extent);
1758                         memmove(ex + 1, ex + 2, len);
1759                 }
1760                 le16_add_cpu(&eh->eh_entries, -1);
1761                 merge_done = 1;
1762                 WARN_ON(eh->eh_entries == 0);
1763                 if (!eh->eh_entries)
1764                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1765         }
1766
1767         return merge_done;
1768 }
1769
1770 /*
1771  * This function does a very simple check to see if we can collapse
1772  * an extent tree with a single extent tree leaf block into the inode.
1773  */
1774 static void ext4_ext_try_to_merge_up(handle_t *handle,
1775                                      struct inode *inode,
1776                                      struct ext4_ext_path *path)
1777 {
1778         size_t s;
1779         unsigned max_root = ext4_ext_space_root(inode, 0);
1780         ext4_fsblk_t blk;
1781
1782         if ((path[0].p_depth != 1) ||
1783             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1784             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1785                 return;
1786
1787         /*
1788          * We need to modify the block allocation bitmap and the block
1789          * group descriptor to release the extent tree block.  If we
1790          * can't get the journal credits, give up.
1791          */
1792         if (ext4_journal_extend(handle, 2))
1793                 return;
1794
1795         /*
1796          * Copy the extent data up to the inode
1797          */
1798         blk = ext4_idx_pblock(path[0].p_idx);
1799         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1800                 sizeof(struct ext4_extent_idx);
1801         s += sizeof(struct ext4_extent_header);
1802
1803         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1804         path[0].p_depth = 0;
1805         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1806                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1807         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1808
1809         brelse(path[1].p_bh);
1810         ext4_free_blocks(handle, inode, NULL, blk, 1,
1811                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1812 }
1813
1814 /*
1815  * This function tries to merge the @ex extent to neighbours in the tree.
1816  * return 1 if merge left else 0.
1817  */
1818 static void ext4_ext_try_to_merge(handle_t *handle,
1819                                   struct inode *inode,
1820                                   struct ext4_ext_path *path,
1821                                   struct ext4_extent *ex) {
1822         struct ext4_extent_header *eh;
1823         unsigned int depth;
1824         int merge_done = 0;
1825
1826         depth = ext_depth(inode);
1827         BUG_ON(path[depth].p_hdr == NULL);
1828         eh = path[depth].p_hdr;
1829
1830         if (ex > EXT_FIRST_EXTENT(eh))
1831                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1832
1833         if (!merge_done)
1834                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1835
1836         ext4_ext_try_to_merge_up(handle, inode, path);
1837 }
1838
1839 /*
1840  * check if a portion of the "newext" extent overlaps with an
1841  * existing extent.
1842  *
1843  * If there is an overlap discovered, it updates the length of the newext
1844  * such that there will be no overlap, and then returns 1.
1845  * If there is no overlap found, it returns 0.
1846  */
1847 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1848                                            struct inode *inode,
1849                                            struct ext4_extent *newext,
1850                                            struct ext4_ext_path *path)
1851 {
1852         ext4_lblk_t b1, b2;
1853         unsigned int depth, len1;
1854         unsigned int ret = 0;
1855
1856         b1 = le32_to_cpu(newext->ee_block);
1857         len1 = ext4_ext_get_actual_len(newext);
1858         depth = ext_depth(inode);
1859         if (!path[depth].p_ext)
1860                 goto out;
1861         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1862
1863         /*
1864          * get the next allocated block if the extent in the path
1865          * is before the requested block(s)
1866          */
1867         if (b2 < b1) {
1868                 b2 = ext4_ext_next_allocated_block(path);
1869                 if (b2 == EXT_MAX_BLOCKS)
1870                         goto out;
1871                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1872         }
1873
1874         /* check for wrap through zero on extent logical start block*/
1875         if (b1 + len1 < b1) {
1876                 len1 = EXT_MAX_BLOCKS - b1;
1877                 newext->ee_len = cpu_to_le16(len1);
1878                 ret = 1;
1879         }
1880
1881         /* check for overlap */
1882         if (b1 + len1 > b2) {
1883                 newext->ee_len = cpu_to_le16(b2 - b1);
1884                 ret = 1;
1885         }
1886 out:
1887         return ret;
1888 }
1889
1890 /*
1891  * ext4_ext_insert_extent:
1892  * tries to merge requsted extent into the existing extent or
1893  * inserts requested extent as new one into the tree,
1894  * creating new leaf in the no-space case.
1895  */
1896 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1897                                 struct ext4_ext_path *path,
1898                                 struct ext4_extent *newext, int gb_flags)
1899 {
1900         struct ext4_extent_header *eh;
1901         struct ext4_extent *ex, *fex;
1902         struct ext4_extent *nearex; /* nearest extent */
1903         struct ext4_ext_path *npath = NULL;
1904         int depth, len, err;
1905         ext4_lblk_t next;
1906         int mb_flags = 0, unwritten;
1907
1908         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1909                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1910                 return -EIO;
1911         }
1912         depth = ext_depth(inode);
1913         ex = path[depth].p_ext;
1914         eh = path[depth].p_hdr;
1915         if (unlikely(path[depth].p_hdr == NULL)) {
1916                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1917                 return -EIO;
1918         }
1919
1920         /* try to insert block into found extent and return */
1921         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1922
1923                 /*
1924                  * Try to see whether we should rather test the extent on
1925                  * right from ex, or from the left of ex. This is because
1926                  * ext4_ext_find_extent() can return either extent on the
1927                  * left, or on the right from the searched position. This
1928                  * will make merging more effective.
1929                  */
1930                 if (ex < EXT_LAST_EXTENT(eh) &&
1931                     (le32_to_cpu(ex->ee_block) +
1932                     ext4_ext_get_actual_len(ex) <
1933                     le32_to_cpu(newext->ee_block))) {
1934                         ex += 1;
1935                         goto prepend;
1936                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1937                            (le32_to_cpu(newext->ee_block) +
1938                            ext4_ext_get_actual_len(newext) <
1939                            le32_to_cpu(ex->ee_block)))
1940                         ex -= 1;
1941
1942                 /* Try to append newex to the ex */
1943                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1944                         ext_debug("append [%d]%d block to %u:[%d]%d"
1945                                   "(from %llu)\n",
1946                                   ext4_ext_is_unwritten(newext),
1947                                   ext4_ext_get_actual_len(newext),
1948                                   le32_to_cpu(ex->ee_block),
1949                                   ext4_ext_is_unwritten(ex),
1950                                   ext4_ext_get_actual_len(ex),
1951                                   ext4_ext_pblock(ex));
1952                         err = ext4_ext_get_access(handle, inode,
1953                                                   path + depth);
1954                         if (err)
1955                                 return err;
1956                         unwritten = ext4_ext_is_unwritten(ex);
1957                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1958                                         + ext4_ext_get_actual_len(newext));
1959                         if (unwritten)
1960                                 ext4_ext_mark_unwritten(ex);
1961                         eh = path[depth].p_hdr;
1962                         nearex = ex;
1963                         goto merge;
1964                 }
1965
1966 prepend:
1967                 /* Try to prepend newex to the ex */
1968                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
1969                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
1970                                   "(from %llu)\n",
1971                                   le32_to_cpu(newext->ee_block),
1972                                   ext4_ext_is_unwritten(newext),
1973                                   ext4_ext_get_actual_len(newext),
1974                                   le32_to_cpu(ex->ee_block),
1975                                   ext4_ext_is_unwritten(ex),
1976                                   ext4_ext_get_actual_len(ex),
1977                                   ext4_ext_pblock(ex));
1978                         err = ext4_ext_get_access(handle, inode,
1979                                                   path + depth);
1980                         if (err)
1981                                 return err;
1982
1983                         unwritten = ext4_ext_is_unwritten(ex);
1984                         ex->ee_block = newext->ee_block;
1985                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
1986                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1987                                         + ext4_ext_get_actual_len(newext));
1988                         if (unwritten)
1989                                 ext4_ext_mark_unwritten(ex);
1990                         eh = path[depth].p_hdr;
1991                         nearex = ex;
1992                         goto merge;
1993                 }
1994         }
1995
1996         depth = ext_depth(inode);
1997         eh = path[depth].p_hdr;
1998         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1999                 goto has_space;
2000
2001         /* probably next leaf has space for us? */
2002         fex = EXT_LAST_EXTENT(eh);
2003         next = EXT_MAX_BLOCKS;
2004         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2005                 next = ext4_ext_next_leaf_block(path);
2006         if (next != EXT_MAX_BLOCKS) {
2007                 ext_debug("next leaf block - %u\n", next);
2008                 BUG_ON(npath != NULL);
2009                 npath = ext4_ext_find_extent(inode, next, NULL, 0);
2010                 if (IS_ERR(npath))
2011                         return PTR_ERR(npath);
2012                 BUG_ON(npath->p_depth != path->p_depth);
2013                 eh = npath[depth].p_hdr;
2014                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2015                         ext_debug("next leaf isn't full(%d)\n",
2016                                   le16_to_cpu(eh->eh_entries));
2017                         path = npath;
2018                         goto has_space;
2019                 }
2020                 ext_debug("next leaf has no free space(%d,%d)\n",
2021                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2022         }
2023
2024         /*
2025          * There is no free space in the found leaf.
2026          * We're gonna add a new leaf in the tree.
2027          */
2028         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2029                 mb_flags = EXT4_MB_USE_RESERVED;
2030         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2031                                        path, newext);
2032         if (err)
2033                 goto cleanup;
2034         depth = ext_depth(inode);
2035         eh = path[depth].p_hdr;
2036
2037 has_space:
2038         nearex = path[depth].p_ext;
2039
2040         err = ext4_ext_get_access(handle, inode, path + depth);
2041         if (err)
2042                 goto cleanup;
2043
2044         if (!nearex) {
2045                 /* there is no extent in this leaf, create first one */
2046                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2047                                 le32_to_cpu(newext->ee_block),
2048                                 ext4_ext_pblock(newext),
2049                                 ext4_ext_is_unwritten(newext),
2050                                 ext4_ext_get_actual_len(newext));
2051                 nearex = EXT_FIRST_EXTENT(eh);
2052         } else {
2053                 if (le32_to_cpu(newext->ee_block)
2054                            > le32_to_cpu(nearex->ee_block)) {
2055                         /* Insert after */
2056                         ext_debug("insert %u:%llu:[%d]%d before: "
2057                                         "nearest %p\n",
2058                                         le32_to_cpu(newext->ee_block),
2059                                         ext4_ext_pblock(newext),
2060                                         ext4_ext_is_unwritten(newext),
2061                                         ext4_ext_get_actual_len(newext),
2062                                         nearex);
2063                         nearex++;
2064                 } else {
2065                         /* Insert before */
2066                         BUG_ON(newext->ee_block == nearex->ee_block);
2067                         ext_debug("insert %u:%llu:[%d]%d after: "
2068                                         "nearest %p\n",
2069                                         le32_to_cpu(newext->ee_block),
2070                                         ext4_ext_pblock(newext),
2071                                         ext4_ext_is_unwritten(newext),
2072                                         ext4_ext_get_actual_len(newext),
2073                                         nearex);
2074                 }
2075                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2076                 if (len > 0) {
2077                         ext_debug("insert %u:%llu:[%d]%d: "
2078                                         "move %d extents from 0x%p to 0x%p\n",
2079                                         le32_to_cpu(newext->ee_block),
2080                                         ext4_ext_pblock(newext),
2081                                         ext4_ext_is_unwritten(newext),
2082                                         ext4_ext_get_actual_len(newext),
2083                                         len, nearex, nearex + 1);
2084                         memmove(nearex + 1, nearex,
2085                                 len * sizeof(struct ext4_extent));
2086                 }
2087         }
2088
2089         le16_add_cpu(&eh->eh_entries, 1);
2090         path[depth].p_ext = nearex;
2091         nearex->ee_block = newext->ee_block;
2092         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2093         nearex->ee_len = newext->ee_len;
2094
2095 merge:
2096         /* try to merge extents */
2097         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2098                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2099
2100
2101         /* time to correct all indexes above */
2102         err = ext4_ext_correct_indexes(handle, inode, path);
2103         if (err)
2104                 goto cleanup;
2105
2106         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2107
2108 cleanup:
2109         if (npath) {
2110                 ext4_ext_drop_refs(npath);
2111                 kfree(npath);
2112         }
2113         return err;
2114 }
2115
2116 static int ext4_fill_fiemap_extents(struct inode *inode,
2117                                     ext4_lblk_t block, ext4_lblk_t num,
2118                                     struct fiemap_extent_info *fieinfo)
2119 {
2120         struct ext4_ext_path *path = NULL;
2121         struct ext4_extent *ex;
2122         struct extent_status es;
2123         ext4_lblk_t next, next_del, start = 0, end = 0;
2124         ext4_lblk_t last = block + num;
2125         int exists, depth = 0, err = 0;
2126         unsigned int flags = 0;
2127         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2128
2129         while (block < last && block != EXT_MAX_BLOCKS) {
2130                 num = last - block;
2131                 /* find extent for this block */
2132                 down_read(&EXT4_I(inode)->i_data_sem);
2133
2134                 if (path && ext_depth(inode) != depth) {
2135                         /* depth was changed. we have to realloc path */
2136                         kfree(path);
2137                         path = NULL;
2138                 }
2139
2140                 path = ext4_ext_find_extent(inode, block, path, 0);
2141                 if (IS_ERR(path)) {
2142                         up_read(&EXT4_I(inode)->i_data_sem);
2143                         err = PTR_ERR(path);
2144                         path = NULL;
2145                         break;
2146                 }
2147
2148                 depth = ext_depth(inode);
2149                 if (unlikely(path[depth].p_hdr == NULL)) {
2150                         up_read(&EXT4_I(inode)->i_data_sem);
2151                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2152                         err = -EIO;
2153                         break;
2154                 }
2155                 ex = path[depth].p_ext;
2156                 next = ext4_ext_next_allocated_block(path);
2157                 ext4_ext_drop_refs(path);
2158
2159                 flags = 0;
2160                 exists = 0;
2161                 if (!ex) {
2162                         /* there is no extent yet, so try to allocate
2163                          * all requested space */
2164                         start = block;
2165                         end = block + num;
2166                 } else if (le32_to_cpu(ex->ee_block) > block) {
2167                         /* need to allocate space before found extent */
2168                         start = block;
2169                         end = le32_to_cpu(ex->ee_block);
2170                         if (block + num < end)
2171                                 end = block + num;
2172                 } else if (block >= le32_to_cpu(ex->ee_block)
2173                                         + ext4_ext_get_actual_len(ex)) {
2174                         /* need to allocate space after found extent */
2175                         start = block;
2176                         end = block + num;
2177                         if (end >= next)
2178                                 end = next;
2179                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2180                         /*
2181                          * some part of requested space is covered
2182                          * by found extent
2183                          */
2184                         start = block;
2185                         end = le32_to_cpu(ex->ee_block)
2186                                 + ext4_ext_get_actual_len(ex);
2187                         if (block + num < end)
2188                                 end = block + num;
2189                         exists = 1;
2190                 } else {
2191                         BUG();
2192                 }
2193                 BUG_ON(end <= start);
2194
2195                 if (!exists) {
2196                         es.es_lblk = start;
2197                         es.es_len = end - start;
2198                         es.es_pblk = 0;
2199                 } else {
2200                         es.es_lblk = le32_to_cpu(ex->ee_block);
2201                         es.es_len = ext4_ext_get_actual_len(ex);
2202                         es.es_pblk = ext4_ext_pblock(ex);
2203                         if (ext4_ext_is_unwritten(ex))
2204                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2205                 }
2206
2207                 /*
2208                  * Find delayed extent and update es accordingly. We call
2209                  * it even in !exists case to find out whether es is the
2210                  * last existing extent or not.
2211                  */
2212                 next_del = ext4_find_delayed_extent(inode, &es);
2213                 if (!exists && next_del) {
2214                         exists = 1;
2215                         flags |= (FIEMAP_EXTENT_DELALLOC |
2216                                   FIEMAP_EXTENT_UNKNOWN);
2217                 }
2218                 up_read(&EXT4_I(inode)->i_data_sem);
2219
2220                 if (unlikely(es.es_len == 0)) {
2221                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2222                         err = -EIO;
2223                         break;
2224                 }
2225
2226                 /*
2227                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2228                  * we need to check next == EXT_MAX_BLOCKS because it is
2229                  * possible that an extent is with unwritten and delayed
2230                  * status due to when an extent is delayed allocated and
2231                  * is allocated by fallocate status tree will track both of
2232                  * them in a extent.
2233                  *
2234                  * So we could return a unwritten and delayed extent, and
2235                  * its block is equal to 'next'.
2236                  */
2237                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2238                         flags |= FIEMAP_EXTENT_LAST;
2239                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2240                                      next != EXT_MAX_BLOCKS)) {
2241                                 EXT4_ERROR_INODE(inode,
2242                                                  "next extent == %u, next "
2243                                                  "delalloc extent = %u",
2244                                                  next, next_del);
2245                                 err = -EIO;
2246                                 break;
2247                         }
2248                 }
2249
2250                 if (exists) {
2251                         err = fiemap_fill_next_extent(fieinfo,
2252                                 (__u64)es.es_lblk << blksize_bits,
2253                                 (__u64)es.es_pblk << blksize_bits,
2254                                 (__u64)es.es_len << blksize_bits,
2255                                 flags);
2256                         if (err < 0)
2257                                 break;
2258                         if (err == 1) {
2259                                 err = 0;
2260                                 break;
2261                         }
2262                 }
2263
2264                 block = es.es_lblk + es.es_len;
2265         }
2266
2267         if (path) {
2268                 ext4_ext_drop_refs(path);
2269                 kfree(path);
2270         }
2271
2272         return err;
2273 }
2274
2275 /*
2276  * ext4_ext_put_gap_in_cache:
2277  * calculate boundaries of the gap that the requested block fits into
2278  * and cache this gap
2279  */
2280 static void
2281 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
2282                                 ext4_lblk_t block)
2283 {
2284         int depth = ext_depth(inode);
2285         unsigned long len = 0;
2286         ext4_lblk_t lblock = 0;
2287         struct ext4_extent *ex;
2288
2289         ex = path[depth].p_ext;
2290         if (ex == NULL) {
2291                 /*
2292                  * there is no extent yet, so gap is [0;-] and we
2293                  * don't cache it
2294                  */
2295                 ext_debug("cache gap(whole file):");
2296         } else if (block < le32_to_cpu(ex->ee_block)) {
2297                 lblock = block;
2298                 len = le32_to_cpu(ex->ee_block) - block;
2299                 ext_debug("cache gap(before): %u [%u:%u]",
2300                                 block,
2301                                 le32_to_cpu(ex->ee_block),
2302                                  ext4_ext_get_actual_len(ex));
2303                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2304                         ext4_es_insert_extent(inode, lblock, len, ~0,
2305                                               EXTENT_STATUS_HOLE);
2306         } else if (block >= le32_to_cpu(ex->ee_block)
2307                         + ext4_ext_get_actual_len(ex)) {
2308                 ext4_lblk_t next;
2309                 lblock = le32_to_cpu(ex->ee_block)
2310                         + ext4_ext_get_actual_len(ex);
2311
2312                 next = ext4_ext_next_allocated_block(path);
2313                 ext_debug("cache gap(after): [%u:%u] %u",
2314                                 le32_to_cpu(ex->ee_block),
2315                                 ext4_ext_get_actual_len(ex),
2316                                 block);
2317                 BUG_ON(next == lblock);
2318                 len = next - lblock;
2319                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2320                         ext4_es_insert_extent(inode, lblock, len, ~0,
2321                                               EXTENT_STATUS_HOLE);
2322         } else {
2323                 BUG();
2324         }
2325
2326         ext_debug(" -> %u:%lu\n", lblock, len);
2327 }
2328
2329 /*
2330  * ext4_ext_rm_idx:
2331  * removes index from the index block.
2332  */
2333 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2334                         struct ext4_ext_path *path, int depth)
2335 {
2336         int err;
2337         ext4_fsblk_t leaf;
2338
2339         /* free index block */
2340         depth--;
2341         path = path + depth;
2342         leaf = ext4_idx_pblock(path->p_idx);
2343         if (unlikely(path->p_hdr->eh_entries == 0)) {
2344                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2345                 return -EIO;
2346         }
2347         err = ext4_ext_get_access(handle, inode, path);
2348         if (err)
2349                 return err;
2350
2351         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2352                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2353                 len *= sizeof(struct ext4_extent_idx);
2354                 memmove(path->p_idx, path->p_idx + 1, len);
2355         }
2356
2357         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2358         err = ext4_ext_dirty(handle, inode, path);
2359         if (err)
2360                 return err;
2361         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2362         trace_ext4_ext_rm_idx(inode, leaf);
2363
2364         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2365                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2366
2367         while (--depth >= 0) {
2368                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2369                         break;
2370                 path--;
2371                 err = ext4_ext_get_access(handle, inode, path);
2372                 if (err)
2373                         break;
2374                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2375                 err = ext4_ext_dirty(handle, inode, path);
2376                 if (err)
2377                         break;
2378         }
2379         return err;
2380 }
2381
2382 /*
2383  * ext4_ext_calc_credits_for_single_extent:
2384  * This routine returns max. credits that needed to insert an extent
2385  * to the extent tree.
2386  * When pass the actual path, the caller should calculate credits
2387  * under i_data_sem.
2388  */
2389 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2390                                                 struct ext4_ext_path *path)
2391 {
2392         if (path) {
2393                 int depth = ext_depth(inode);
2394                 int ret = 0;
2395
2396                 /* probably there is space in leaf? */
2397                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2398                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2399
2400                         /*
2401                          *  There are some space in the leaf tree, no
2402                          *  need to account for leaf block credit
2403                          *
2404                          *  bitmaps and block group descriptor blocks
2405                          *  and other metadata blocks still need to be
2406                          *  accounted.
2407                          */
2408                         /* 1 bitmap, 1 block group descriptor */
2409                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2410                         return ret;
2411                 }
2412         }
2413
2414         return ext4_chunk_trans_blocks(inode, nrblocks);
2415 }
2416
2417 /*
2418  * How many index/leaf blocks need to change/allocate to add @extents extents?
2419  *
2420  * If we add a single extent, then in the worse case, each tree level
2421  * index/leaf need to be changed in case of the tree split.
2422  *
2423  * If more extents are inserted, they could cause the whole tree split more
2424  * than once, but this is really rare.
2425  */
2426 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2427 {
2428         int index;
2429         int depth;
2430
2431         /* If we are converting the inline data, only one is needed here. */
2432         if (ext4_has_inline_data(inode))
2433                 return 1;
2434
2435         depth = ext_depth(inode);
2436
2437         if (extents <= 1)
2438                 index = depth * 2;
2439         else
2440                 index = depth * 3;
2441
2442         return index;
2443 }
2444
2445 static inline int get_default_free_blocks_flags(struct inode *inode)
2446 {
2447         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2448                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2449         else if (ext4_should_journal_data(inode))
2450                 return EXT4_FREE_BLOCKS_FORGET;
2451         return 0;
2452 }
2453
2454 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2455                               struct ext4_extent *ex,
2456                               long long *partial_cluster,
2457                               ext4_lblk_t from, ext4_lblk_t to)
2458 {
2459         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2460         unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2461         ext4_fsblk_t pblk;
2462         int flags = get_default_free_blocks_flags(inode);
2463
2464         /*
2465          * For bigalloc file systems, we never free a partial cluster
2466          * at the beginning of the extent.  Instead, we make a note
2467          * that we tried freeing the cluster, and check to see if we
2468          * need to free it on a subsequent call to ext4_remove_blocks,
2469          * or at the end of the ext4_truncate() operation.
2470          */
2471         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2472
2473         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2474         /*
2475          * If we have a partial cluster, and it's different from the
2476          * cluster of the last block, we need to explicitly free the
2477          * partial cluster here.
2478          */
2479         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2480         if ((*partial_cluster > 0) &&
2481             (EXT4_B2C(sbi, pblk) != *partial_cluster)) {
2482                 ext4_free_blocks(handle, inode, NULL,
2483                                  EXT4_C2B(sbi, *partial_cluster),
2484                                  sbi->s_cluster_ratio, flags);
2485                 *partial_cluster = 0;
2486         }
2487
2488 #ifdef EXTENTS_STATS
2489         {
2490                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2491                 spin_lock(&sbi->s_ext_stats_lock);
2492                 sbi->s_ext_blocks += ee_len;
2493                 sbi->s_ext_extents++;
2494                 if (ee_len < sbi->s_ext_min)
2495                         sbi->s_ext_min = ee_len;
2496                 if (ee_len > sbi->s_ext_max)
2497                         sbi->s_ext_max = ee_len;
2498                 if (ext_depth(inode) > sbi->s_depth_max)
2499                         sbi->s_depth_max = ext_depth(inode);
2500                 spin_unlock(&sbi->s_ext_stats_lock);
2501         }
2502 #endif
2503         if (from >= le32_to_cpu(ex->ee_block)
2504             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2505                 /* tail removal */
2506                 ext4_lblk_t num;
2507                 unsigned int unaligned;
2508
2509                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2510                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2511                 /*
2512                  * Usually we want to free partial cluster at the end of the
2513                  * extent, except for the situation when the cluster is still
2514                  * used by any other extent (partial_cluster is negative).
2515                  */
2516                 if (*partial_cluster < 0 &&
2517                     -(*partial_cluster) == EXT4_B2C(sbi, pblk + num - 1))
2518                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2519
2520                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2521                           num, pblk, *partial_cluster);
2522                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2523                 /*
2524                  * If the block range to be freed didn't start at the
2525                  * beginning of a cluster, and we removed the entire
2526                  * extent and the cluster is not used by any other extent,
2527                  * save the partial cluster here, since we might need to
2528                  * delete if we determine that the truncate operation has
2529                  * removed all of the blocks in the cluster.
2530                  *
2531                  * On the other hand, if we did not manage to free the whole
2532                  * extent, we have to mark the cluster as used (store negative
2533                  * cluster number in partial_cluster).
2534                  */
2535                 unaligned = EXT4_PBLK_COFF(sbi, pblk);
2536                 if (unaligned && (ee_len == num) &&
2537                     (*partial_cluster != -((long long)EXT4_B2C(sbi, pblk))))
2538                         *partial_cluster = EXT4_B2C(sbi, pblk);
2539                 else if (unaligned)
2540                         *partial_cluster = -((long long)EXT4_B2C(sbi, pblk));
2541                 else if (*partial_cluster > 0)
2542                         *partial_cluster = 0;
2543         } else
2544                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2545                            "%u-%u from %u:%u\n",
2546                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2547         return 0;
2548 }
2549
2550
2551 /*
2552  * ext4_ext_rm_leaf() Removes the extents associated with the
2553  * blocks appearing between "start" and "end", and splits the extents
2554  * if "start" and "end" appear in the same extent
2555  *
2556  * @handle: The journal handle
2557  * @inode:  The files inode
2558  * @path:   The path to the leaf
2559  * @partial_cluster: The cluster which we'll have to free if all extents
2560  *                   has been released from it. It gets negative in case
2561  *                   that the cluster is still used.
2562  * @start:  The first block to remove
2563  * @end:   The last block to remove
2564  */
2565 static int
2566 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2567                  struct ext4_ext_path *path,
2568                  long long *partial_cluster,
2569                  ext4_lblk_t start, ext4_lblk_t end)
2570 {
2571         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2572         int err = 0, correct_index = 0;
2573         int depth = ext_depth(inode), credits;
2574         struct ext4_extent_header *eh;
2575         ext4_lblk_t a, b;
2576         unsigned num;
2577         ext4_lblk_t ex_ee_block;
2578         unsigned short ex_ee_len;
2579         unsigned unwritten = 0;
2580         struct ext4_extent *ex;
2581         ext4_fsblk_t pblk;
2582
2583         /* the header must be checked already in ext4_ext_remove_space() */
2584         ext_debug("truncate since %u in leaf to %u\n", start, end);
2585         if (!path[depth].p_hdr)
2586                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2587         eh = path[depth].p_hdr;
2588         if (unlikely(path[depth].p_hdr == NULL)) {
2589                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2590                 return -EIO;
2591         }
2592         /* find where to start removing */
2593         ex = path[depth].p_ext;
2594         if (!ex)
2595                 ex = EXT_LAST_EXTENT(eh);
2596
2597         ex_ee_block = le32_to_cpu(ex->ee_block);
2598         ex_ee_len = ext4_ext_get_actual_len(ex);
2599
2600         /*
2601          * If we're starting with an extent other than the last one in the
2602          * node, we need to see if it shares a cluster with the extent to
2603          * the right (towards the end of the file). If its leftmost cluster
2604          * is this extent's rightmost cluster and it is not cluster aligned,
2605          * we'll mark it as a partial that is not to be deallocated.
2606          */
2607
2608         if (ex != EXT_LAST_EXTENT(eh)) {
2609                 ext4_fsblk_t current_pblk, right_pblk;
2610                 long long current_cluster, right_cluster;
2611
2612                 current_pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2613                 current_cluster = (long long)EXT4_B2C(sbi, current_pblk);
2614                 right_pblk = ext4_ext_pblock(ex + 1);
2615                 right_cluster = (long long)EXT4_B2C(sbi, right_pblk);
2616                 if (current_cluster == right_cluster &&
2617                         EXT4_PBLK_COFF(sbi, right_pblk))
2618                         *partial_cluster = -right_cluster;
2619         }
2620
2621         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2622
2623         while (ex >= EXT_FIRST_EXTENT(eh) &&
2624                         ex_ee_block + ex_ee_len > start) {
2625
2626                 if (ext4_ext_is_unwritten(ex))
2627                         unwritten = 1;
2628                 else
2629                         unwritten = 0;
2630
2631                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2632                           unwritten, ex_ee_len);
2633                 path[depth].p_ext = ex;
2634
2635                 a = ex_ee_block > start ? ex_ee_block : start;
2636                 b = ex_ee_block+ex_ee_len - 1 < end ?
2637                         ex_ee_block+ex_ee_len - 1 : end;
2638
2639                 ext_debug("  border %u:%u\n", a, b);
2640
2641                 /* If this extent is beyond the end of the hole, skip it */
2642                 if (end < ex_ee_block) {
2643                         /*
2644                          * We're going to skip this extent and move to another,
2645                          * so if this extent is not cluster aligned we have
2646                          * to mark the current cluster as used to avoid
2647                          * accidentally freeing it later on
2648                          */
2649                         pblk = ext4_ext_pblock(ex);
2650                         if (EXT4_PBLK_COFF(sbi, pblk))
2651                                 *partial_cluster =
2652                                         -((long long)EXT4_B2C(sbi, pblk));
2653                         ex--;
2654                         ex_ee_block = le32_to_cpu(ex->ee_block);
2655                         ex_ee_len = ext4_ext_get_actual_len(ex);
2656                         continue;
2657                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2658                         EXT4_ERROR_INODE(inode,
2659                                          "can not handle truncate %u:%u "
2660                                          "on extent %u:%u",
2661                                          start, end, ex_ee_block,
2662                                          ex_ee_block + ex_ee_len - 1);
2663                         err = -EIO;
2664                         goto out;
2665                 } else if (a != ex_ee_block) {
2666                         /* remove tail of the extent */
2667                         num = a - ex_ee_block;
2668                 } else {
2669                         /* remove whole extent: excellent! */
2670                         num = 0;
2671                 }
2672                 /*
2673                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2674                  * descriptor) for each block group; assume two block
2675                  * groups plus ex_ee_len/blocks_per_block_group for
2676                  * the worst case
2677                  */
2678                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2679                 if (ex == EXT_FIRST_EXTENT(eh)) {
2680                         correct_index = 1;
2681                         credits += (ext_depth(inode)) + 1;
2682                 }
2683                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2684
2685                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2686                 if (err)
2687                         goto out;
2688
2689                 err = ext4_ext_get_access(handle, inode, path + depth);
2690                 if (err)
2691                         goto out;
2692
2693                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2694                                          a, b);
2695                 if (err)
2696                         goto out;
2697
2698                 if (num == 0)
2699                         /* this extent is removed; mark slot entirely unused */
2700                         ext4_ext_store_pblock(ex, 0);
2701
2702                 ex->ee_len = cpu_to_le16(num);
2703                 /*
2704                  * Do not mark unwritten if all the blocks in the
2705                  * extent have been removed.
2706                  */
2707                 if (unwritten && num)
2708                         ext4_ext_mark_unwritten(ex);
2709                 /*
2710                  * If the extent was completely released,
2711                  * we need to remove it from the leaf
2712                  */
2713                 if (num == 0) {
2714                         if (end != EXT_MAX_BLOCKS - 1) {
2715                                 /*
2716                                  * For hole punching, we need to scoot all the
2717                                  * extents up when an extent is removed so that
2718                                  * we dont have blank extents in the middle
2719                                  */
2720                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2721                                         sizeof(struct ext4_extent));
2722
2723                                 /* Now get rid of the one at the end */
2724                                 memset(EXT_LAST_EXTENT(eh), 0,
2725                                         sizeof(struct ext4_extent));
2726                         }
2727                         le16_add_cpu(&eh->eh_entries, -1);
2728                 } else if (*partial_cluster > 0)
2729                         *partial_cluster = 0;
2730
2731                 err = ext4_ext_dirty(handle, inode, path + depth);
2732                 if (err)
2733                         goto out;
2734
2735                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2736                                 ext4_ext_pblock(ex));
2737                 ex--;
2738                 ex_ee_block = le32_to_cpu(ex->ee_block);
2739                 ex_ee_len = ext4_ext_get_actual_len(ex);
2740         }
2741
2742         if (correct_index && eh->eh_entries)
2743                 err = ext4_ext_correct_indexes(handle, inode, path);
2744
2745         /*
2746          * If there's a partial cluster and at least one extent remains in
2747          * the leaf, free the partial cluster if it isn't shared with the
2748          * current extent.  If there's a partial cluster and no extents
2749          * remain in the leaf, it can't be freed here.  It can only be
2750          * freed when it's possible to determine if it's not shared with
2751          * any other extent - when the next leaf is processed or when space
2752          * removal is complete.
2753          */
2754         if (*partial_cluster > 0 && eh->eh_entries &&
2755             (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) !=
2756              *partial_cluster)) {
2757                 int flags = get_default_free_blocks_flags(inode);
2758
2759                 ext4_free_blocks(handle, inode, NULL,
2760                                  EXT4_C2B(sbi, *partial_cluster),
2761                                  sbi->s_cluster_ratio, flags);
2762                 *partial_cluster = 0;
2763         }
2764
2765         /* if this leaf is free, then we should
2766          * remove it from index block above */
2767         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2768                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2769
2770 out:
2771         return err;
2772 }
2773
2774 /*
2775  * ext4_ext_more_to_rm:
2776  * returns 1 if current index has to be freed (even partial)
2777  */
2778 static int
2779 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2780 {
2781         BUG_ON(path->p_idx == NULL);
2782
2783         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2784                 return 0;
2785
2786         /*
2787          * if truncate on deeper level happened, it wasn't partial,
2788          * so we have to consider current index for truncation
2789          */
2790         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2791                 return 0;
2792         return 1;
2793 }
2794
2795 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2796                           ext4_lblk_t end)
2797 {
2798         struct super_block *sb = inode->i_sb;
2799         int depth = ext_depth(inode);
2800         struct ext4_ext_path *path = NULL;
2801         long long partial_cluster = 0;
2802         handle_t *handle;
2803         int i = 0, err = 0;
2804
2805         ext_debug("truncate since %u to %u\n", start, end);
2806
2807         /* probably first extent we're gonna free will be last in block */
2808         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2809         if (IS_ERR(handle))
2810                 return PTR_ERR(handle);
2811
2812 again:
2813         trace_ext4_ext_remove_space(inode, start, end, depth);
2814
2815         /*
2816          * Check if we are removing extents inside the extent tree. If that
2817          * is the case, we are going to punch a hole inside the extent tree
2818          * so we have to check whether we need to split the extent covering
2819          * the last block to remove so we can easily remove the part of it
2820          * in ext4_ext_rm_leaf().
2821          */
2822         if (end < EXT_MAX_BLOCKS - 1) {
2823                 struct ext4_extent *ex;
2824                 ext4_lblk_t ee_block;
2825
2826                 /* find extent for this block */
2827                 path = ext4_ext_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2828                 if (IS_ERR(path)) {
2829                         ext4_journal_stop(handle);
2830                         return PTR_ERR(path);
2831                 }
2832                 depth = ext_depth(inode);
2833                 /* Leaf not may not exist only if inode has no blocks at all */
2834                 ex = path[depth].p_ext;
2835                 if (!ex) {
2836                         if (depth) {
2837                                 EXT4_ERROR_INODE(inode,
2838                                                  "path[%d].p_hdr == NULL",
2839                                                  depth);
2840                                 err = -EIO;
2841                         }
2842                         goto out;
2843                 }
2844
2845                 ee_block = le32_to_cpu(ex->ee_block);
2846
2847                 /*
2848                  * See if the last block is inside the extent, if so split
2849                  * the extent at 'end' block so we can easily remove the
2850                  * tail of the first part of the split extent in
2851                  * ext4_ext_rm_leaf().
2852                  */
2853                 if (end >= ee_block &&
2854                     end < ee_block + ext4_ext_get_actual_len(ex) - 1) {
2855                         int split_flag = 0;
2856
2857                         if (ext4_ext_is_unwritten(ex))
2858                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
2859                                              EXT4_EXT_MARK_UNWRIT2;
2860
2861                         /*
2862                          * Split the extent in two so that 'end' is the last
2863                          * block in the first new extent. Also we should not
2864                          * fail removing space due to ENOSPC so try to use
2865                          * reserved block if that happens.
2866                          */
2867                         err = ext4_split_extent_at(handle, inode, path,
2868                                         end + 1, split_flag,
2869                                         EXT4_EX_NOCACHE |
2870                                         EXT4_GET_BLOCKS_PRE_IO |
2871                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
2872
2873                         if (err < 0)
2874                                 goto out;
2875                 }
2876         }
2877         /*
2878          * We start scanning from right side, freeing all the blocks
2879          * after i_size and walking into the tree depth-wise.
2880          */
2881         depth = ext_depth(inode);
2882         if (path) {
2883                 int k = i = depth;
2884                 while (--k > 0)
2885                         path[k].p_block =
2886                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2887         } else {
2888                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2889                                GFP_NOFS);
2890                 if (path == NULL) {
2891                         ext4_journal_stop(handle);
2892                         return -ENOMEM;
2893                 }
2894                 path[0].p_depth = depth;
2895                 path[0].p_hdr = ext_inode_hdr(inode);
2896                 i = 0;
2897
2898                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2899                         err = -EIO;
2900                         goto out;
2901                 }
2902         }
2903         err = 0;
2904
2905         while (i >= 0 && err == 0) {
2906                 if (i == depth) {
2907                         /* this is leaf block */
2908                         err = ext4_ext_rm_leaf(handle, inode, path,
2909                                                &partial_cluster, start,
2910                                                end);
2911                         /* root level has p_bh == NULL, brelse() eats this */
2912                         brelse(path[i].p_bh);
2913                         path[i].p_bh = NULL;
2914                         i--;
2915                         continue;
2916                 }
2917
2918                 /* this is index block */
2919                 if (!path[i].p_hdr) {
2920                         ext_debug("initialize header\n");
2921                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2922                 }
2923
2924                 if (!path[i].p_idx) {
2925                         /* this level hasn't been touched yet */
2926                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2927                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2928                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2929                                   path[i].p_hdr,
2930                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2931                 } else {
2932                         /* we were already here, see at next index */
2933                         path[i].p_idx--;
2934                 }
2935
2936                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2937                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2938                                 path[i].p_idx);
2939                 if (ext4_ext_more_to_rm(path + i)) {
2940                         struct buffer_head *bh;
2941                         /* go to the next level */
2942                         ext_debug("move to level %d (block %llu)\n",
2943                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2944                         memset(path + i + 1, 0, sizeof(*path));
2945                         bh = read_extent_tree_block(inode,
2946                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2947                                 EXT4_EX_NOCACHE);
2948                         if (IS_ERR(bh)) {
2949                                 /* should we reset i_size? */
2950                                 err = PTR_ERR(bh);
2951                                 break;
2952                         }
2953                         /* Yield here to deal with large extent trees.
2954                          * Should be a no-op if we did IO above. */
2955                         cond_resched();
2956                         if (WARN_ON(i + 1 > depth)) {
2957                                 err = -EIO;
2958                                 break;
2959                         }
2960                         path[i + 1].p_bh = bh;
2961
2962                         /* save actual number of indexes since this
2963                          * number is changed at the next iteration */
2964                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2965                         i++;
2966                 } else {
2967                         /* we finished processing this index, go up */
2968                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2969                                 /* index is empty, remove it;
2970                                  * handle must be already prepared by the
2971                                  * truncatei_leaf() */
2972                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2973                         }
2974                         /* root level has p_bh == NULL, brelse() eats this */
2975                         brelse(path[i].p_bh);
2976                         path[i].p_bh = NULL;
2977                         i--;
2978                         ext_debug("return to level %d\n", i);
2979                 }
2980         }
2981
2982         trace_ext4_ext_remove_space_done(inode, start, end, depth,
2983                         partial_cluster, path->p_hdr->eh_entries);
2984
2985         /* If we still have something in the partial cluster and we have removed
2986          * even the first extent, then we should free the blocks in the partial
2987          * cluster as well. */
2988         if (partial_cluster > 0 && path->p_hdr->eh_entries == 0) {
2989                 int flags = get_default_free_blocks_flags(inode);
2990
2991                 ext4_free_blocks(handle, inode, NULL,
2992                                  EXT4_C2B(EXT4_SB(sb), partial_cluster),
2993                                  EXT4_SB(sb)->s_cluster_ratio, flags);
2994                 partial_cluster = 0;
2995         }
2996
2997         /* TODO: flexible tree reduction should be here */
2998         if (path->p_hdr->eh_entries == 0) {
2999                 /*
3000                  * truncate to zero freed all the tree,
3001                  * so we need to correct eh_depth
3002                  */
3003                 err = ext4_ext_get_access(handle, inode, path);
3004                 if (err == 0) {
3005                         ext_inode_hdr(inode)->eh_depth = 0;
3006                         ext_inode_hdr(inode)->eh_max =
3007                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3008                         err = ext4_ext_dirty(handle, inode, path);
3009                 }
3010         }
3011 out:
3012         ext4_ext_drop_refs(path);
3013         kfree(path);
3014         if (err == -EAGAIN) {
3015                 path = NULL;
3016                 goto again;
3017         }
3018         ext4_journal_stop(handle);
3019
3020         return err;
3021 }
3022
3023 /*
3024  * called at mount time
3025  */
3026 void ext4_ext_init(struct super_block *sb)
3027 {
3028         /*
3029          * possible initialization would be here
3030          */
3031
3032         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
3033 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3034                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3035 #ifdef AGGRESSIVE_TEST
3036                        ", aggressive tests"
3037 #endif
3038 #ifdef CHECK_BINSEARCH
3039                        ", check binsearch"
3040 #endif
3041 #ifdef EXTENTS_STATS
3042                        ", stats"
3043 #endif
3044                        "\n");
3045 #endif
3046 #ifdef EXTENTS_STATS
3047                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3048                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3049                 EXT4_SB(sb)->s_ext_max = 0;
3050 #endif
3051         }
3052 }
3053
3054 /*
3055  * called at umount time
3056  */
3057 void ext4_ext_release(struct super_block *sb)
3058 {
3059         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
3060                 return;
3061
3062 #ifdef EXTENTS_STATS
3063         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3064                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3065                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3066                         sbi->s_ext_blocks, sbi->s_ext_extents,
3067                         sbi->s_ext_blocks / sbi->s_ext_extents);
3068                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3069                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3070         }
3071 #endif
3072 }
3073
3074 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3075 {
3076         ext4_lblk_t  ee_block;
3077         ext4_fsblk_t ee_pblock;
3078         unsigned int ee_len;
3079
3080         ee_block  = le32_to_cpu(ex->ee_block);
3081         ee_len    = ext4_ext_get_actual_len(ex);
3082         ee_pblock = ext4_ext_pblock(ex);
3083
3084         if (ee_len == 0)
3085                 return 0;
3086
3087         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3088                                      EXTENT_STATUS_WRITTEN);
3089 }
3090
3091 /* FIXME!! we need to try to merge to left or right after zero-out  */
3092 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3093 {
3094         ext4_fsblk_t ee_pblock;
3095         unsigned int ee_len;
3096         int ret;
3097
3098         ee_len    = ext4_ext_get_actual_len(ex);
3099         ee_pblock = ext4_ext_pblock(ex);
3100
3101         ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
3102         if (ret > 0)
3103                 ret = 0;
3104
3105         return ret;
3106 }
3107
3108 /*
3109  * ext4_split_extent_at() splits an extent at given block.
3110  *
3111  * @handle: the journal handle
3112  * @inode: the file inode
3113  * @path: the path to the extent
3114  * @split: the logical block where the extent is splitted.
3115  * @split_flags: indicates if the extent could be zeroout if split fails, and
3116  *               the states(init or unwritten) of new extents.
3117  * @flags: flags used to insert new extent to extent tree.
3118  *
3119  *
3120  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3121  * of which are deterimined by split_flag.
3122  *
3123  * There are two cases:
3124  *  a> the extent are splitted into two extent.
3125  *  b> split is not needed, and just mark the extent.
3126  *
3127  * return 0 on success.
3128  */
3129 static int ext4_split_extent_at(handle_t *handle,
3130                              struct inode *inode,
3131                              struct ext4_ext_path *path,
3132                              ext4_lblk_t split,
3133                              int split_flag,
3134                              int flags)
3135 {
3136         ext4_fsblk_t newblock;
3137         ext4_lblk_t ee_block;
3138         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3139         struct ext4_extent *ex2 = NULL;
3140         unsigned int ee_len, depth;
3141         int err = 0;
3142
3143         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3144                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3145
3146         ext_debug("ext4_split_extents_at: inode %lu, logical"
3147                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3148
3149         ext4_ext_show_leaf(inode, path);
3150
3151         depth = ext_depth(inode);
3152         ex = path[depth].p_ext;
3153         ee_block = le32_to_cpu(ex->ee_block);
3154         ee_len = ext4_ext_get_actual_len(ex);
3155         newblock = split - ee_block + ext4_ext_pblock(ex);
3156
3157         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3158         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3159                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3160                              EXT4_EXT_MARK_UNWRIT1 |
3161                              EXT4_EXT_MARK_UNWRIT2));
3162
3163         err = ext4_ext_get_access(handle, inode, path + depth);
3164         if (err)
3165                 goto out;
3166
3167         if (split == ee_block) {
3168                 /*
3169                  * case b: block @split is the block that the extent begins with
3170                  * then we just change the state of the extent, and splitting
3171                  * is not needed.
3172                  */
3173                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3174                         ext4_ext_mark_unwritten(ex);
3175                 else
3176                         ext4_ext_mark_initialized(ex);
3177
3178                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3179                         ext4_ext_try_to_merge(handle, inode, path, ex);
3180
3181                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3182                 goto out;
3183         }
3184
3185         /* case a */
3186         memcpy(&orig_ex, ex, sizeof(orig_ex));
3187         ex->ee_len = cpu_to_le16(split - ee_block);
3188         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3189                 ext4_ext_mark_unwritten(ex);
3190
3191         /*
3192          * path may lead to new leaf, not to original leaf any more
3193          * after ext4_ext_insert_extent() returns,
3194          */
3195         err = ext4_ext_dirty(handle, inode, path + depth);
3196         if (err)
3197                 goto fix_extent_len;
3198
3199         ex2 = &newex;
3200         ex2->ee_block = cpu_to_le32(split);
3201         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3202         ext4_ext_store_pblock(ex2, newblock);
3203         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3204                 ext4_ext_mark_unwritten(ex2);
3205
3206         err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
3207         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3208                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3209                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3210                                 err = ext4_ext_zeroout(inode, ex2);
3211                                 zero_ex.ee_block = ex2->ee_block;
3212                                 zero_ex.ee_len = cpu_to_le16(
3213                                                 ext4_ext_get_actual_len(ex2));
3214                                 ext4_ext_store_pblock(&zero_ex,
3215                                                       ext4_ext_pblock(ex2));
3216                         } else {
3217                                 err = ext4_ext_zeroout(inode, ex);
3218                                 zero_ex.ee_block = ex->ee_block;
3219                                 zero_ex.ee_len = cpu_to_le16(
3220                                                 ext4_ext_get_actual_len(ex));
3221                                 ext4_ext_store_pblock(&zero_ex,
3222                                                       ext4_ext_pblock(ex));
3223                         }
3224                 } else {
3225                         err = ext4_ext_zeroout(inode, &orig_ex);
3226                         zero_ex.ee_block = orig_ex.ee_block;
3227                         zero_ex.ee_len = cpu_to_le16(
3228                                                 ext4_ext_get_actual_len(&orig_ex));
3229                         ext4_ext_store_pblock(&zero_ex,
3230                                               ext4_ext_pblock(&orig_ex));
3231                 }
3232
3233                 if (err)
3234                         goto fix_extent_len;
3235                 /* update the extent length and mark as initialized */
3236                 ex->ee_len = cpu_to_le16(ee_len);
3237                 ext4_ext_try_to_merge(handle, inode, path, ex);
3238                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3239                 if (err)
3240                         goto fix_extent_len;
3241
3242                 /* update extent status tree */
3243                 err = ext4_zeroout_es(inode, &zero_ex);
3244
3245                 goto out;
3246         } else if (err)
3247                 goto fix_extent_len;
3248
3249 out:
3250         ext4_ext_show_leaf(inode, path);
3251         return err;
3252
3253 fix_extent_len:
3254         ex->ee_len = orig_ex.ee_len;
3255         ext4_ext_dirty(handle, inode, path + depth);
3256         return err;
3257 }
3258
3259 /*
3260  * ext4_split_extents() splits an extent and mark extent which is covered
3261  * by @map as split_flags indicates
3262  *
3263  * It may result in splitting the extent into multiple extents (up to three)
3264  * There are three possibilities:
3265  *   a> There is no split required
3266  *   b> Splits in two extents: Split is happening at either end of the extent
3267  *   c> Splits in three extents: Somone is splitting in middle of the extent
3268  *
3269  */
3270 static int ext4_split_extent(handle_t *handle,
3271                               struct inode *inode,
3272                               struct ext4_ext_path *path,
3273                               struct ext4_map_blocks *map,
3274                               int split_flag,
3275                               int flags)
3276 {
3277         ext4_lblk_t ee_block;
3278         struct ext4_extent *ex;
3279         unsigned int ee_len, depth;
3280         int err = 0;
3281         int unwritten;
3282         int split_flag1, flags1;
3283         int allocated = map->m_len;
3284
3285         depth = ext_depth(inode);
3286         ex = path[depth].p_ext;
3287         ee_block = le32_to_cpu(ex->ee_block);
3288         ee_len = ext4_ext_get_actual_len(ex);
3289         unwritten = ext4_ext_is_unwritten(ex);
3290
3291         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3292                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3293                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3294                 if (unwritten)
3295                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3296                                        EXT4_EXT_MARK_UNWRIT2;
3297                 if (split_flag & EXT4_EXT_DATA_VALID2)
3298                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3299                 err = ext4_split_extent_at(handle, inode, path,
3300                                 map->m_lblk + map->m_len, split_flag1, flags1);
3301                 if (err)
3302                         goto out;
3303         } else {
3304                 allocated = ee_len - (map->m_lblk - ee_block);
3305         }
3306         /*
3307          * Update path is required because previous ext4_split_extent_at() may
3308          * result in split of original leaf or extent zeroout.
3309          */
3310         ext4_ext_drop_refs(path);
3311         path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3312         if (IS_ERR(path))
3313                 return PTR_ERR(path);
3314         depth = ext_depth(inode);
3315         ex = path[depth].p_ext;
3316         if (!ex) {
3317                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3318                                  (unsigned long) map->m_lblk);
3319                 return -EIO;
3320         }
3321         unwritten = ext4_ext_is_unwritten(ex);
3322         split_flag1 = 0;
3323
3324         if (map->m_lblk >= ee_block) {
3325                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3326                 if (unwritten) {
3327                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3328                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3329                                                      EXT4_EXT_MARK_UNWRIT2);
3330                 }
3331                 err = ext4_split_extent_at(handle, inode, path,
3332                                 map->m_lblk, split_flag1, flags);
3333                 if (err)
3334                         goto out;
3335         }
3336
3337         ext4_ext_show_leaf(inode, path);
3338 out:
3339         return err ? err : allocated;
3340 }
3341
3342 /*
3343  * This function is called by ext4_ext_map_blocks() if someone tries to write
3344  * to an unwritten extent. It may result in splitting the unwritten
3345  * extent into multiple extents (up to three - one initialized and two
3346  * unwritten).
3347  * There are three possibilities:
3348  *   a> There is no split required: Entire extent should be initialized
3349  *   b> Splits in two extents: Write is happening at either end of the extent
3350  *   c> Splits in three extents: Somone is writing in middle of the extent
3351  *
3352  * Pre-conditions:
3353  *  - The extent pointed to by 'path' is unwritten.
3354  *  - The extent pointed to by 'path' contains a superset
3355  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3356  *
3357  * Post-conditions on success:
3358  *  - the returned value is the number of blocks beyond map->l_lblk
3359  *    that are allocated and initialized.
3360  *    It is guaranteed to be >= map->m_len.
3361  */
3362 static int ext4_ext_convert_to_initialized(handle_t *handle,
3363                                            struct inode *inode,
3364                                            struct ext4_map_blocks *map,
3365                                            struct ext4_ext_path *path,
3366                                            int flags)
3367 {
3368         struct ext4_sb_info *sbi;
3369         struct ext4_extent_header *eh;
3370         struct ext4_map_blocks split_map;
3371         struct ext4_extent zero_ex;
3372         struct ext4_extent *ex, *abut_ex;
3373         ext4_lblk_t ee_block, eof_block;
3374         unsigned int ee_len, depth, map_len = map->m_len;
3375         int allocated = 0, max_zeroout = 0;
3376         int err = 0;
3377         int split_flag = 0;
3378
3379         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3380                 "block %llu, max_blocks %u\n", inode->i_ino,
3381                 (unsigned long long)map->m_lblk, map_len);
3382
3383         sbi = EXT4_SB(inode->i_sb);
3384         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3385                 inode->i_sb->s_blocksize_bits;
3386         if (eof_block < map->m_lblk + map_len)
3387                 eof_block = map->m_lblk + map_len;
3388
3389         depth = ext_depth(inode);
3390         eh = path[depth].p_hdr;
3391         ex = path[depth].p_ext;
3392         ee_block = le32_to_cpu(ex->ee_block);
3393         ee_len = ext4_ext_get_actual_len(ex);
3394         zero_ex.ee_len = 0;
3395
3396         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3397
3398         /* Pre-conditions */
3399         BUG_ON(!ext4_ext_is_unwritten(ex));
3400         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3401
3402         /*
3403          * Attempt to transfer newly initialized blocks from the currently
3404          * unwritten extent to its neighbor. This is much cheaper
3405          * than an insertion followed by a merge as those involve costly
3406          * memmove() calls. Transferring to the left is the common case in
3407          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3408          * followed by append writes.
3409          *
3410          * Limitations of the current logic:
3411          *  - L1: we do not deal with writes covering the whole extent.
3412          *    This would require removing the extent if the transfer
3413          *    is possible.
3414          *  - L2: we only attempt to merge with an extent stored in the
3415          *    same extent tree node.
3416          */
3417         if ((map->m_lblk == ee_block) &&
3418                 /* See if we can merge left */
3419                 (map_len < ee_len) &&           /*L1*/
3420                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3421                 ext4_lblk_t prev_lblk;
3422                 ext4_fsblk_t prev_pblk, ee_pblk;
3423                 unsigned int prev_len;
3424
3425                 abut_ex = ex - 1;
3426                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3427                 prev_len = ext4_ext_get_actual_len(abut_ex);
3428                 prev_pblk = ext4_ext_pblock(abut_ex);
3429                 ee_pblk = ext4_ext_pblock(ex);
3430
3431                 /*
3432                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3433                  * upon those conditions:
3434                  * - C1: abut_ex is initialized,
3435                  * - C2: abut_ex is logically abutting ex,
3436                  * - C3: abut_ex is physically abutting ex,
3437                  * - C4: abut_ex can receive the additional blocks without
3438                  *   overflowing the (initialized) length limit.
3439                  */
3440                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3441                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3442                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3443                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3444                         err = ext4_ext_get_access(handle, inode, path + depth);
3445                         if (err)
3446                                 goto out;
3447
3448                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3449                                 map, ex, abut_ex);
3450
3451                         /* Shift the start of ex by 'map_len' blocks */
3452                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3453                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3454                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3455                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3456
3457                         /* Extend abut_ex by 'map_len' blocks */
3458                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3459
3460                         /* Result: number of initialized blocks past m_lblk */
3461                         allocated = map_len;
3462                 }
3463         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3464                    (map_len < ee_len) &&        /*L1*/
3465                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3466                 /* See if we can merge right */
3467                 ext4_lblk_t next_lblk;
3468                 ext4_fsblk_t next_pblk, ee_pblk;
3469                 unsigned int next_len;
3470
3471                 abut_ex = ex + 1;
3472                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3473                 next_len = ext4_ext_get_actual_len(abut_ex);
3474                 next_pblk = ext4_ext_pblock(abut_ex);
3475                 ee_pblk = ext4_ext_pblock(ex);
3476
3477                 /*
3478                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3479                  * upon those conditions:
3480                  * - C1: abut_ex is initialized,
3481                  * - C2: abut_ex is logically abutting ex,
3482                  * - C3: abut_ex is physically abutting ex,
3483                  * - C4: abut_ex can receive the additional blocks without
3484                  *   overflowing the (initialized) length limit.
3485                  */
3486                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3487                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3488                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3489                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3490                         err = ext4_ext_get_access(handle, inode, path + depth);
3491                         if (err)
3492                                 goto out;
3493
3494                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3495                                 map, ex, abut_ex);
3496
3497                         /* Shift the start of abut_ex by 'map_len' blocks */
3498                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3499                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3500                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3501                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3502
3503                         /* Extend abut_ex by 'map_len' blocks */
3504                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3505
3506                         /* Result: number of initialized blocks past m_lblk */
3507                         allocated = map_len;
3508                 }
3509         }
3510         if (allocated) {
3511                 /* Mark the block containing both extents as dirty */
3512                 ext4_ext_dirty(handle, inode, path + depth);
3513
3514                 /* Update path to point to the right extent */
3515                 path[depth].p_ext = abut_ex;
3516                 goto out;
3517         } else
3518                 allocated = ee_len - (map->m_lblk - ee_block);
3519
3520         WARN_ON(map->m_lblk < ee_block);
3521         /*
3522          * It is safe to convert extent to initialized via explicit
3523          * zeroout only if extent is fully inside i_size or new_size.
3524          */
3525         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3526
3527         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3528                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3529                         (inode->i_sb->s_blocksize_bits - 10);
3530
3531         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3532         if (max_zeroout && (ee_len <= max_zeroout)) {
3533                 err = ext4_ext_zeroout(inode, ex);
3534                 if (err)
3535                         goto out;
3536                 zero_ex.ee_block = ex->ee_block;
3537                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3538                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3539
3540                 err = ext4_ext_get_access(handle, inode, path + depth);
3541                 if (err)
3542                         goto out;
3543                 ext4_ext_mark_initialized(ex);
3544                 ext4_ext_try_to_merge(handle, inode, path, ex);
3545                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3546                 goto out;
3547         }
3548
3549         /*
3550          * four cases:
3551          * 1. split the extent into three extents.
3552          * 2. split the extent into two extents, zeroout the first half.
3553          * 3. split the extent into two extents, zeroout the second half.
3554          * 4. split the extent into two extents with out zeroout.
3555          */
3556         split_map.m_lblk = map->m_lblk;
3557         split_map.m_len = map->m_len;
3558
3559         if (max_zeroout && (allocated > map->m_len)) {
3560                 if (allocated <= max_zeroout) {
3561                         /* case 3 */
3562                         zero_ex.ee_block =
3563                                          cpu_to_le32(map->m_lblk);
3564                         zero_ex.ee_len = cpu_to_le16(allocated);
3565                         ext4_ext_store_pblock(&zero_ex,
3566                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3567                         err = ext4_ext_zeroout(inode, &zero_ex);
3568                         if (err)
3569                                 goto out;
3570                         split_map.m_lblk = map->m_lblk;
3571                         split_map.m_len = allocated;
3572                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3573                         /* case 2 */
3574                         if (map->m_lblk != ee_block) {
3575                                 zero_ex.ee_block = ex->ee_block;
3576                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3577                                                         ee_block);
3578                                 ext4_ext_store_pblock(&zero_ex,
3579                                                       ext4_ext_pblock(ex));
3580                                 err = ext4_ext_zeroout(inode, &zero_ex);
3581                                 if (err)
3582                                         goto out;
3583                         }
3584
3585                         split_map.m_lblk = ee_block;
3586                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3587                         allocated = map->m_len;
3588                 }
3589         }
3590
3591         allocated = ext4_split_extent(handle, inode, path,
3592                                       &split_map, split_flag, flags);
3593         if (allocated < 0)
3594                 err = allocated;
3595
3596 out:
3597         /* If we have gotten a failure, don't zero out status tree */
3598         if (!err)
3599                 err = ext4_zeroout_es(inode, &zero_ex);
3600         return err ? err : allocated;
3601 }
3602
3603 /*
3604  * This function is called by ext4_ext_map_blocks() from
3605  * ext4_get_blocks_dio_write() when DIO to write
3606  * to an unwritten extent.
3607  *
3608  * Writing to an unwritten extent may result in splitting the unwritten
3609  * extent into multiple initialized/unwritten extents (up to three)
3610  * There are three possibilities:
3611  *   a> There is no split required: Entire extent should be unwritten
3612  *   b> Splits in two extents: Write is happening at either end of the extent
3613  *   c> Splits in three extents: Somone is writing in middle of the extent
3614  *
3615  * This works the same way in the case of initialized -> unwritten conversion.
3616  *
3617  * One of more index blocks maybe needed if the extent tree grow after
3618  * the unwritten extent split. To prevent ENOSPC occur at the IO
3619  * complete, we need to split the unwritten extent before DIO submit
3620  * the IO. The unwritten extent called at this time will be split
3621  * into three unwritten extent(at most). After IO complete, the part
3622  * being filled will be convert to initialized by the end_io callback function
3623  * via ext4_convert_unwritten_extents().
3624  *
3625  * Returns the size of unwritten extent to be written on success.
3626  */
3627 static int ext4_split_convert_extents(handle_t *handle,
3628                                         struct inode *inode,
3629                                         struct ext4_map_blocks *map,
3630                                         struct ext4_ext_path *path,
3631                                         int flags)
3632 {
3633         ext4_lblk_t eof_block;
3634         ext4_lblk_t ee_block;
3635         struct ext4_extent *ex;
3636         unsigned int ee_len;
3637         int split_flag = 0, depth;
3638
3639         ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3640                   __func__, inode->i_ino,
3641                   (unsigned long long)map->m_lblk, map->m_len);
3642
3643         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3644                 inode->i_sb->s_blocksize_bits;
3645         if (eof_block < map->m_lblk + map->m_len)
3646                 eof_block = map->m_lblk + map->m_len;
3647         /*
3648          * It is safe to convert extent to initialized via explicit
3649          * zeroout only if extent is fully insde i_size or new_size.
3650          */
3651         depth = ext_depth(inode);
3652         ex = path[depth].p_ext;
3653         ee_block = le32_to_cpu(ex->ee_block);
3654         ee_len = ext4_ext_get_actual_len(ex);
3655
3656         /* Convert to unwritten */
3657         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3658                 split_flag |= EXT4_EXT_DATA_VALID1;
3659         /* Convert to initialized */
3660         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3661                 split_flag |= ee_block + ee_len <= eof_block ?
3662                               EXT4_EXT_MAY_ZEROOUT : 0;
3663                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3664         }
3665         flags |= EXT4_GET_BLOCKS_PRE_IO;
3666         return ext4_split_extent(handle, inode, path, map, split_flag, flags);
3667 }
3668
3669 static int ext4_convert_initialized_extents(handle_t *handle,
3670                                             struct inode *inode,
3671                                             struct ext4_map_blocks *map,
3672                                             struct ext4_ext_path *path)
3673 {
3674         struct ext4_extent *ex;
3675         ext4_lblk_t ee_block;
3676         unsigned int ee_len;
3677         int depth;
3678         int err = 0;
3679
3680         depth = ext_depth(inode);
3681         ex = path[depth].p_ext;
3682         ee_block = le32_to_cpu(ex->ee_block);
3683         ee_len = ext4_ext_get_actual_len(ex);
3684
3685         ext_debug("%s: inode %lu, logical"
3686                 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3687                   (unsigned long long)ee_block, ee_len);
3688
3689         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3690                 err = ext4_split_convert_extents(handle, inode, map, path,
3691                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3692                 if (err < 0)
3693                         goto out;
3694                 ext4_ext_drop_refs(path);
3695                 path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3696                 if (IS_ERR(path)) {
3697                         err = PTR_ERR(path);
3698                         goto out;
3699                 }
3700                 depth = ext_depth(inode);
3701                 ex = path[depth].p_ext;
3702                 if (!ex) {
3703                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3704                                          (unsigned long) map->m_lblk);
3705                         err = -EIO;
3706                         goto out;
3707                 }
3708         }
3709
3710         err = ext4_ext_get_access(handle, inode, path + depth);
3711         if (err)
3712                 goto out;
3713         /* first mark the extent as unwritten */
3714         ext4_ext_mark_unwritten(ex);
3715
3716         /* note: ext4_ext_correct_indexes() isn't needed here because
3717          * borders are not changed
3718          */
3719         ext4_ext_try_to_merge(handle, inode, path, ex);
3720
3721         /* Mark modified extent as dirty */
3722         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3723 out:
3724         ext4_ext_show_leaf(inode, path);
3725         return err;
3726 }
3727
3728
3729 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3730                                                 struct inode *inode,
3731                                                 struct ext4_map_blocks *map,
3732                                                 struct ext4_ext_path *path)
3733 {
3734         struct ext4_extent *ex;
3735         ext4_lblk_t ee_block;
3736         unsigned int ee_len;
3737         int depth;
3738         int err = 0;
3739
3740         depth = ext_depth(inode);
3741         ex = path[depth].p_ext;
3742         ee_block = le32_to_cpu(ex->ee_block);
3743         ee_len = ext4_ext_get_actual_len(ex);
3744
3745         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3746                 "block %llu, max_blocks %u\n", inode->i_ino,
3747                   (unsigned long long)ee_block, ee_len);
3748
3749         /* If extent is larger than requested it is a clear sign that we still
3750          * have some extent state machine issues left. So extent_split is still
3751          * required.
3752          * TODO: Once all related issues will be fixed this situation should be
3753          * illegal.
3754          */
3755         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3756 #ifdef EXT4_DEBUG
3757                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3758                              " len %u; IO logical block %llu, len %u\n",
3759                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3760                              (unsigned long long)map->m_lblk, map->m_len);
3761 #endif
3762                 err = ext4_split_convert_extents(handle, inode, map, path,
3763                                                  EXT4_GET_BLOCKS_CONVERT);
3764                 if (err < 0)
3765                         goto out;
3766                 ext4_ext_drop_refs(path);
3767                 path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3768                 if (IS_ERR(path)) {
3769                         err = PTR_ERR(path);
3770                         goto out;
3771                 }
3772                 depth = ext_depth(inode);
3773                 ex = path[depth].p_ext;
3774         }
3775
3776         err = ext4_ext_get_access(handle, inode, path + depth);
3777         if (err)
3778                 goto out;
3779         /* first mark the extent as initialized */
3780         ext4_ext_mark_initialized(ex);
3781
3782         /* note: ext4_ext_correct_indexes() isn't needed here because
3783          * borders are not changed
3784          */
3785         ext4_ext_try_to_merge(handle, inode, path, ex);
3786
3787         /* Mark modified extent as dirty */
3788         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3789 out:
3790         ext4_ext_show_leaf(inode, path);
3791         return err;
3792 }
3793
3794 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3795                         sector_t block, int count)
3796 {
3797         int i;
3798         for (i = 0; i < count; i++)
3799                 unmap_underlying_metadata(bdev, block + i);
3800 }
3801
3802 /*
3803  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3804  */
3805 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3806                               ext4_lblk_t lblk,
3807                               struct ext4_ext_path *path,
3808                               unsigned int len)
3809 {
3810         int i, depth;
3811         struct ext4_extent_header *eh;
3812         struct ext4_extent *last_ex;
3813
3814         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3815                 return 0;
3816
3817         depth = ext_depth(inode);
3818         eh = path[depth].p_hdr;
3819
3820         /*
3821          * We're going to remove EOFBLOCKS_FL entirely in future so we
3822          * do not care for this case anymore. Simply remove the flag
3823          * if there are no extents.
3824          */
3825         if (unlikely(!eh->eh_entries))
3826                 goto out;
3827         last_ex = EXT_LAST_EXTENT(eh);
3828         /*
3829          * We should clear the EOFBLOCKS_FL flag if we are writing the
3830          * last block in the last extent in the file.  We test this by
3831          * first checking to see if the caller to
3832          * ext4_ext_get_blocks() was interested in the last block (or
3833          * a block beyond the last block) in the current extent.  If
3834          * this turns out to be false, we can bail out from this
3835          * function immediately.
3836          */
3837         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3838             ext4_ext_get_actual_len(last_ex))
3839                 return 0;
3840         /*
3841          * If the caller does appear to be planning to write at or
3842          * beyond the end of the current extent, we then test to see
3843          * if the current extent is the last extent in the file, by
3844          * checking to make sure it was reached via the rightmost node
3845          * at each level of the tree.
3846          */
3847         for (i = depth-1; i >= 0; i--)
3848                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3849                         return 0;
3850 out:
3851         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3852         return ext4_mark_inode_dirty(handle, inode);
3853 }
3854
3855 /**
3856  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3857  *
3858  * Return 1 if there is a delalloc block in the range, otherwise 0.
3859  */
3860 int ext4_find_delalloc_range(struct inode *inode,
3861                              ext4_lblk_t lblk_start,
3862                              ext4_lblk_t lblk_end)
3863 {
3864         struct extent_status es;
3865
3866         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3867         if (es.es_len == 0)
3868                 return 0; /* there is no delay extent in this tree */
3869         else if (es.es_lblk <= lblk_start &&
3870                  lblk_start < es.es_lblk + es.es_len)
3871                 return 1;
3872         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3873                 return 1;
3874         else
3875                 return 0;
3876 }
3877
3878 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3879 {
3880         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3881         ext4_lblk_t lblk_start, lblk_end;
3882         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3883         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3884
3885         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3886 }
3887
3888 /**
3889  * Determines how many complete clusters (out of those specified by the 'map')
3890  * are under delalloc and were reserved quota for.
3891  * This function is called when we are writing out the blocks that were
3892  * originally written with their allocation delayed, but then the space was
3893  * allocated using fallocate() before the delayed allocation could be resolved.
3894  * The cases to look for are:
3895  * ('=' indicated delayed allocated blocks
3896  *  '-' indicates non-delayed allocated blocks)
3897  * (a) partial clusters towards beginning and/or end outside of allocated range
3898  *     are not delalloc'ed.
3899  *      Ex:
3900  *      |----c---=|====c====|====c====|===-c----|
3901  *               |++++++ allocated ++++++|
3902  *      ==> 4 complete clusters in above example
3903  *
3904  * (b) partial cluster (outside of allocated range) towards either end is
3905  *     marked for delayed allocation. In this case, we will exclude that
3906  *     cluster.
3907  *      Ex:
3908  *      |----====c========|========c========|
3909  *           |++++++ allocated ++++++|
3910  *      ==> 1 complete clusters in above example
3911  *
3912  *      Ex:
3913  *      |================c================|
3914  *            |++++++ allocated ++++++|
3915  *      ==> 0 complete clusters in above example
3916  *
3917  * The ext4_da_update_reserve_space will be called only if we
3918  * determine here that there were some "entire" clusters that span
3919  * this 'allocated' range.
3920  * In the non-bigalloc case, this function will just end up returning num_blks
3921  * without ever calling ext4_find_delalloc_range.
3922  */
3923 static unsigned int
3924 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3925                            unsigned int num_blks)
3926 {
3927         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3928         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3929         ext4_lblk_t lblk_from, lblk_to, c_offset;
3930         unsigned int allocated_clusters = 0;
3931
3932         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3933         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3934
3935         /* max possible clusters for this allocation */
3936         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3937
3938         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3939
3940         /* Check towards left side */
3941         c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3942         if (c_offset) {
3943                 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3944                 lblk_to = lblk_from + c_offset - 1;
3945
3946                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3947                         allocated_clusters--;
3948         }
3949
3950         /* Now check towards right. */
3951         c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3952         if (allocated_clusters && c_offset) {
3953                 lblk_from = lblk_start + num_blks;
3954                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3955
3956                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3957                         allocated_clusters--;
3958         }
3959
3960         return allocated_clusters;
3961 }
3962
3963 static int
3964 ext4_ext_convert_initialized_extent(handle_t *handle, struct inode *inode,
3965                         struct ext4_map_blocks *map,
3966                         struct ext4_ext_path *path, int flags,
3967                         unsigned int allocated, ext4_fsblk_t newblock)
3968 {
3969         int ret = 0;
3970         int err = 0;
3971
3972         /*
3973          * Make sure that the extent is no bigger than we support with
3974          * unwritten extent
3975          */
3976         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3977                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3978
3979         ret = ext4_convert_initialized_extents(handle, inode, map,
3980                                                 path);
3981         if (ret >= 0) {
3982                 ext4_update_inode_fsync_trans(handle, inode, 1);
3983                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
3984                                          path, map->m_len);
3985         } else
3986                 err = ret;
3987         map->m_flags |= EXT4_MAP_UNWRITTEN;
3988         if (allocated > map->m_len)
3989                 allocated = map->m_len;
3990         map->m_len = allocated;
3991
3992         return err ? err : allocated;
3993 }
3994
3995 static int
3996 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3997                         struct ext4_map_blocks *map,
3998                         struct ext4_ext_path *path, int flags,
3999                         unsigned int allocated, ext4_fsblk_t newblock)
4000 {
4001         int ret = 0;
4002         int err = 0;
4003         ext4_io_end_t *io = ext4_inode_aio(inode);
4004
4005         ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4006                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
4007                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4008                   flags, allocated);
4009         ext4_ext_show_leaf(inode, path);
4010
4011         /*
4012          * When writing into unwritten space, we should not fail to
4013          * allocate metadata blocks for the new extent block if needed.
4014          */
4015         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4016
4017         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4018                                                     allocated, newblock);
4019
4020         /* get_block() before submit the IO, split the extent */
4021         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4022                 ret = ext4_split_convert_extents(handle, inode, map,
4023                                          path, flags | EXT4_GET_BLOCKS_CONVERT);
4024                 if (ret <= 0)
4025                         goto out;
4026                 /*
4027                  * Flag the inode(non aio case) or end_io struct (aio case)
4028                  * that this IO needs to conversion to written when IO is
4029                  * completed
4030                  */
4031                 if (io)
4032                         ext4_set_io_unwritten_flag(inode, io);
4033                 else
4034                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
4035                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4036                 goto out;
4037         }
4038         /* IO end_io complete, convert the filled extent to written */
4039         if (flags & EXT4_GET_BLOCKS_CONVERT) {
4040                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4041                                                         path);
4042                 if (ret >= 0) {
4043                         ext4_update_inode_fsync_trans(handle, inode, 1);
4044                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
4045                                                  path, map->m_len);
4046                 } else
4047                         err = ret;
4048                 map->m_flags |= EXT4_MAP_MAPPED;
4049                 map->m_pblk = newblock;
4050                 if (allocated > map->m_len)
4051                         allocated = map->m_len;
4052                 map->m_len = allocated;
4053                 goto out2;
4054         }
4055         /* buffered IO case */
4056         /*
4057          * repeat fallocate creation request
4058          * we already have an unwritten extent
4059          */
4060         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4061                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4062                 goto map_out;
4063         }
4064
4065         /* buffered READ or buffered write_begin() lookup */
4066         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4067                 /*
4068                  * We have blocks reserved already.  We
4069                  * return allocated blocks so that delalloc
4070                  * won't do block reservation for us.  But
4071                  * the buffer head will be unmapped so that
4072                  * a read from the block returns 0s.
4073                  */
4074                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4075                 goto out1;
4076         }
4077
4078         /* buffered write, writepage time, convert*/
4079         ret = ext4_ext_convert_to_initialized(handle, inode, map, path, flags);
4080         if (ret >= 0)
4081                 ext4_update_inode_fsync_trans(handle, inode, 1);
4082 out:
4083         if (ret <= 0) {
4084                 err = ret;
4085                 goto out2;
4086         } else
4087                 allocated = ret;
4088         map->m_flags |= EXT4_MAP_NEW;
4089         /*
4090          * if we allocated more blocks than requested
4091          * we need to make sure we unmap the extra block
4092          * allocated. The actual needed block will get
4093          * unmapped later when we find the buffer_head marked
4094          * new.
4095          */
4096         if (allocated > map->m_len) {
4097                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4098                                         newblock + map->m_len,
4099                                         allocated - map->m_len);
4100                 allocated = map->m_len;
4101         }
4102         map->m_len = allocated;
4103
4104         /*
4105          * If we have done fallocate with the offset that is already
4106          * delayed allocated, we would have block reservation
4107          * and quota reservation done in the delayed write path.
4108          * But fallocate would have already updated quota and block
4109          * count for this offset. So cancel these reservation
4110          */
4111         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4112                 unsigned int reserved_clusters;
4113                 reserved_clusters = get_reserved_cluster_alloc(inode,
4114                                 map->m_lblk, map->m_len);
4115                 if (reserved_clusters)
4116                         ext4_da_update_reserve_space(inode,
4117                                                      reserved_clusters,
4118                                                      0);
4119         }
4120
4121 map_out:
4122         map->m_flags |= EXT4_MAP_MAPPED;
4123         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4124                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4125                                          map->m_len);
4126                 if (err < 0)
4127                         goto out2;
4128         }
4129 out1:
4130         if (allocated > map->m_len)
4131                 allocated = map->m_len;
4132         ext4_ext_show_leaf(inode, path);
4133         map->m_pblk = newblock;
4134         map->m_len = allocated;
4135 out2:
4136         return err ? err : allocated;
4137 }
4138
4139 /*
4140  * get_implied_cluster_alloc - check to see if the requested
4141  * allocation (in the map structure) overlaps with a cluster already
4142  * allocated in an extent.
4143  *      @sb     The filesystem superblock structure
4144  *      @map    The requested lblk->pblk mapping
4145  *      @ex     The extent structure which might contain an implied
4146  *                      cluster allocation
4147  *
4148  * This function is called by ext4_ext_map_blocks() after we failed to
4149  * find blocks that were already in the inode's extent tree.  Hence,
4150  * we know that the beginning of the requested region cannot overlap
4151  * the extent from the inode's extent tree.  There are three cases we
4152  * want to catch.  The first is this case:
4153  *
4154  *               |--- cluster # N--|
4155  *    |--- extent ---|  |---- requested region ---|
4156  *                      |==========|
4157  *
4158  * The second case that we need to test for is this one:
4159  *
4160  *   |--------- cluster # N ----------------|
4161  *         |--- requested region --|   |------- extent ----|
4162  *         |=======================|
4163  *
4164  * The third case is when the requested region lies between two extents
4165  * within the same cluster:
4166  *          |------------- cluster # N-------------|
4167  * |----- ex -----|                  |---- ex_right ----|
4168  *                  |------ requested region ------|
4169  *                  |================|
4170  *
4171  * In each of the above cases, we need to set the map->m_pblk and
4172  * map->m_len so it corresponds to the return the extent labelled as
4173  * "|====|" from cluster #N, since it is already in use for data in
4174  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4175  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4176  * as a new "allocated" block region.  Otherwise, we will return 0 and
4177  * ext4_ext_map_blocks() will then allocate one or more new clusters
4178  * by calling ext4_mb_new_blocks().
4179  */
4180 static int get_implied_cluster_alloc(struct super_block *sb,
4181                                      struct ext4_map_blocks *map,
4182                                      struct ext4_extent *ex,
4183                                      struct ext4_ext_path *path)
4184 {
4185         struct ext4_sb_info *sbi = EXT4_SB(sb);
4186         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4187         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4188         ext4_lblk_t rr_cluster_start;
4189         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4190         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4191         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4192
4193         /* The extent passed in that we are trying to match */
4194         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4195         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4196
4197         /* The requested region passed into ext4_map_blocks() */
4198         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4199
4200         if ((rr_cluster_start == ex_cluster_end) ||
4201             (rr_cluster_start == ex_cluster_start)) {
4202                 if (rr_cluster_start == ex_cluster_end)
4203                         ee_start += ee_len - 1;
4204                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4205                 map->m_len = min(map->m_len,
4206                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4207                 /*
4208                  * Check for and handle this case:
4209                  *
4210                  *   |--------- cluster # N-------------|
4211                  *                     |------- extent ----|
4212                  *         |--- requested region ---|
4213                  *         |===========|
4214                  */
4215
4216                 if (map->m_lblk < ee_block)
4217                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4218
4219                 /*
4220                  * Check for the case where there is already another allocated
4221                  * block to the right of 'ex' but before the end of the cluster.
4222                  *
4223                  *          |------------- cluster # N-------------|
4224                  * |----- ex -----|                  |---- ex_right ----|
4225                  *                  |------ requested region ------|
4226                  *                  |================|
4227                  */
4228                 if (map->m_lblk > ee_block) {
4229                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4230                         map->m_len = min(map->m_len, next - map->m_lblk);
4231                 }
4232
4233                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4234                 return 1;
4235         }
4236
4237         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4238         return 0;
4239 }
4240
4241
4242 /*
4243  * Block allocation/map/preallocation routine for extents based files
4244  *
4245  *
4246  * Need to be called with
4247  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4248  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4249  *
4250  * return > 0, number of of blocks already mapped/allocated
4251  *          if create == 0 and these are pre-allocated blocks
4252  *              buffer head is unmapped
4253  *          otherwise blocks are mapped
4254  *
4255  * return = 0, if plain look up failed (blocks have not been allocated)
4256  *          buffer head is unmapped
4257  *
4258  * return < 0, error case.
4259  */
4260 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4261                         struct ext4_map_blocks *map, int flags)
4262 {
4263         struct ext4_ext_path *path = NULL;
4264         struct ext4_extent newex, *ex, *ex2;
4265         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4266         ext4_fsblk_t newblock = 0;
4267         int free_on_err = 0, err = 0, depth, ret;
4268         unsigned int allocated = 0, offset = 0;
4269         unsigned int allocated_clusters = 0;
4270         struct ext4_allocation_request ar;
4271         ext4_io_end_t *io = ext4_inode_aio(inode);
4272         ext4_lblk_t cluster_offset;
4273         int set_unwritten = 0;
4274
4275         ext_debug("blocks %u/%u requested for inode %lu\n",
4276                   map->m_lblk, map->m_len, inode->i_ino);
4277         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4278
4279         /* find extent for this block */
4280         path = ext4_ext_find_extent(inode, map->m_lblk, NULL, 0);
4281         if (IS_ERR(path)) {
4282                 err = PTR_ERR(path);
4283                 path = NULL;
4284                 goto out2;
4285         }
4286
4287         depth = ext_depth(inode);
4288
4289         /*
4290          * consistent leaf must not be empty;
4291          * this situation is possible, though, _during_ tree modification;
4292          * this is why assert can't be put in ext4_ext_find_extent()
4293          */
4294         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4295                 EXT4_ERROR_INODE(inode, "bad extent address "
4296                                  "lblock: %lu, depth: %d pblock %lld",
4297                                  (unsigned long) map->m_lblk, depth,
4298                                  path[depth].p_block);
4299                 err = -EIO;
4300                 goto out2;
4301         }
4302
4303         ex = path[depth].p_ext;
4304         if (ex) {
4305                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4306                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4307                 unsigned short ee_len;
4308
4309
4310                 /*
4311                  * unwritten extents are treated as holes, except that
4312                  * we split out initialized portions during a write.
4313                  */
4314                 ee_len = ext4_ext_get_actual_len(ex);
4315
4316                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4317
4318                 /* if found extent covers block, simply return it */
4319                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4320                         newblock = map->m_lblk - ee_block + ee_start;
4321                         /* number of remaining blocks in the extent */
4322                         allocated = ee_len - (map->m_lblk - ee_block);
4323                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4324                                   ee_block, ee_len, newblock);
4325
4326                         /*
4327                          * If the extent is initialized check whether the
4328                          * caller wants to convert it to unwritten.
4329                          */
4330                         if ((!ext4_ext_is_unwritten(ex)) &&
4331                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4332                                 allocated = ext4_ext_convert_initialized_extent(
4333                                                 handle, inode, map, path, flags,
4334                                                 allocated, newblock);
4335                                 goto out2;
4336                         } else if (!ext4_ext_is_unwritten(ex))
4337                                 goto out;
4338
4339                         ret = ext4_ext_handle_unwritten_extents(
4340                                 handle, inode, map, path, flags,
4341                                 allocated, newblock);
4342                         if (ret < 0)
4343                                 err = ret;
4344                         else
4345                                 allocated = ret;
4346                         goto out2;
4347                 }
4348         }
4349
4350         if ((sbi->s_cluster_ratio > 1) &&
4351             ext4_find_delalloc_cluster(inode, map->m_lblk))
4352                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4353
4354         /*
4355          * requested block isn't allocated yet;
4356          * we couldn't try to create block if create flag is zero
4357          */
4358         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4359                 /*
4360                  * put just found gap into cache to speed up
4361                  * subsequent requests
4362                  */
4363                 if ((flags & EXT4_GET_BLOCKS_NO_PUT_HOLE) == 0)
4364                         ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
4365                 goto out2;
4366         }
4367
4368         /*
4369          * Okay, we need to do block allocation.
4370          */
4371         map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
4372         newex.ee_block = cpu_to_le32(map->m_lblk);
4373         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4374
4375         /*
4376          * If we are doing bigalloc, check to see if the extent returned
4377          * by ext4_ext_find_extent() implies a cluster we can use.
4378          */
4379         if (cluster_offset && ex &&
4380             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4381                 ar.len = allocated = map->m_len;
4382                 newblock = map->m_pblk;
4383                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4384                 goto got_allocated_blocks;
4385         }
4386
4387         /* find neighbour allocated blocks */
4388         ar.lleft = map->m_lblk;
4389         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4390         if (err)
4391                 goto out2;
4392         ar.lright = map->m_lblk;
4393         ex2 = NULL;
4394         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4395         if (err)
4396                 goto out2;
4397
4398         /* Check if the extent after searching to the right implies a
4399          * cluster we can use. */
4400         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4401             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4402                 ar.len = allocated = map->m_len;
4403                 newblock = map->m_pblk;
4404                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4405                 goto got_allocated_blocks;
4406         }
4407
4408         /*
4409          * See if request is beyond maximum number of blocks we can have in
4410          * a single extent. For an initialized extent this limit is
4411          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4412          * EXT_UNWRITTEN_MAX_LEN.
4413          */
4414         if (map->m_len > EXT_INIT_MAX_LEN &&
4415             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4416                 map->m_len = EXT_INIT_MAX_LEN;
4417         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4418                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4419                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4420
4421         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4422         newex.ee_len = cpu_to_le16(map->m_len);
4423         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4424         if (err)
4425                 allocated = ext4_ext_get_actual_len(&newex);
4426         else
4427                 allocated = map->m_len;
4428
4429         /* allocate new block */
4430         ar.inode = inode;
4431         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4432         ar.logical = map->m_lblk;
4433         /*
4434          * We calculate the offset from the beginning of the cluster
4435          * for the logical block number, since when we allocate a
4436          * physical cluster, the physical block should start at the
4437          * same offset from the beginning of the cluster.  This is
4438          * needed so that future calls to get_implied_cluster_alloc()
4439          * work correctly.
4440          */
4441         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4442         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4443         ar.goal -= offset;
4444         ar.logical -= offset;
4445         if (S_ISREG(inode->i_mode))
4446                 ar.flags = EXT4_MB_HINT_DATA;
4447         else
4448                 /* disable in-core preallocation for non-regular files */
4449                 ar.flags = 0;
4450         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4451                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4452         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4453         if (!newblock)
4454                 goto out2;
4455         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4456                   ar.goal, newblock, allocated);
4457         free_on_err = 1;
4458         allocated_clusters = ar.len;
4459         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4460         if (ar.len > allocated)
4461                 ar.len = allocated;
4462
4463 got_allocated_blocks:
4464         /* try to insert new extent into found leaf and return */
4465         ext4_ext_store_pblock(&newex, newblock + offset);
4466         newex.ee_len = cpu_to_le16(ar.len);
4467         /* Mark unwritten */
4468         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4469                 ext4_ext_mark_unwritten(&newex);
4470                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4471                 /*
4472                  * io_end structure was created for every IO write to an
4473                  * unwritten extent. To avoid unnecessary conversion,
4474                  * here we flag the IO that really needs the conversion.
4475                  * For non asycn direct IO case, flag the inode state
4476                  * that we need to perform conversion when IO is done.
4477                  */
4478                 if (flags & EXT4_GET_BLOCKS_PRE_IO)
4479                         set_unwritten = 1;
4480         }
4481
4482         err = 0;
4483         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4484                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4485                                          path, ar.len);
4486         if (!err)
4487                 err = ext4_ext_insert_extent(handle, inode, path,
4488                                              &newex, flags);
4489
4490         if (!err && set_unwritten) {
4491                 if (io)
4492                         ext4_set_io_unwritten_flag(inode, io);
4493                 else
4494                         ext4_set_inode_state(inode,
4495                                              EXT4_STATE_DIO_UNWRITTEN);
4496         }
4497
4498         if (err && free_on_err) {
4499                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4500                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4501                 /* free data blocks we just allocated */
4502                 /* not a good idea to call discard here directly,
4503                  * but otherwise we'd need to call it every free() */
4504                 ext4_discard_preallocations(inode);
4505                 ext4_free_blocks(handle, inode, NULL, newblock,
4506                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4507                 goto out2;
4508         }
4509
4510         /* previous routine could use block we allocated */
4511         newblock = ext4_ext_pblock(&newex);
4512         allocated = ext4_ext_get_actual_len(&newex);
4513         if (allocated > map->m_len)
4514                 allocated = map->m_len;
4515         map->m_flags |= EXT4_MAP_NEW;
4516
4517         /*
4518          * Update reserved blocks/metadata blocks after successful
4519          * block allocation which had been deferred till now.
4520          */
4521         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4522                 unsigned int reserved_clusters;
4523                 /*
4524                  * Check how many clusters we had reserved this allocated range
4525                  */
4526                 reserved_clusters = get_reserved_cluster_alloc(inode,
4527                                                 map->m_lblk, allocated);
4528                 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) {
4529                         if (reserved_clusters) {
4530                                 /*
4531                                  * We have clusters reserved for this range.
4532                                  * But since we are not doing actual allocation
4533                                  * and are simply using blocks from previously
4534                                  * allocated cluster, we should release the
4535                                  * reservation and not claim quota.
4536                                  */
4537                                 ext4_da_update_reserve_space(inode,
4538                                                 reserved_clusters, 0);
4539                         }
4540                 } else {
4541                         BUG_ON(allocated_clusters < reserved_clusters);
4542                         if (reserved_clusters < allocated_clusters) {
4543                                 struct ext4_inode_info *ei = EXT4_I(inode);
4544                                 int reservation = allocated_clusters -
4545                                                   reserved_clusters;
4546                                 /*
4547                                  * It seems we claimed few clusters outside of
4548                                  * the range of this allocation. We should give
4549                                  * it back to the reservation pool. This can
4550                                  * happen in the following case:
4551                                  *
4552                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4553                                  *   cluster has 4 blocks. Thus, the clusters
4554                                  *   are [0-3],[4-7],[8-11]...
4555                                  * * First comes delayed allocation write for
4556                                  *   logical blocks 10 & 11. Since there were no
4557                                  *   previous delayed allocated blocks in the
4558                                  *   range [8-11], we would reserve 1 cluster
4559                                  *   for this write.
4560                                  * * Next comes write for logical blocks 3 to 8.
4561                                  *   In this case, we will reserve 2 clusters
4562                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4563                                  *   that range has a delayed allocated blocks.
4564                                  *   Thus total reserved clusters now becomes 3.
4565                                  * * Now, during the delayed allocation writeout
4566                                  *   time, we will first write blocks [3-8] and
4567                                  *   allocate 3 clusters for writing these
4568                                  *   blocks. Also, we would claim all these
4569                                  *   three clusters above.
4570                                  * * Now when we come here to writeout the
4571                                  *   blocks [10-11], we would expect to claim
4572                                  *   the reservation of 1 cluster we had made
4573                                  *   (and we would claim it since there are no
4574                                  *   more delayed allocated blocks in the range
4575                                  *   [8-11]. But our reserved cluster count had
4576                                  *   already gone to 0.
4577                                  *
4578                                  *   Thus, at the step 4 above when we determine
4579                                  *   that there are still some unwritten delayed
4580                                  *   allocated blocks outside of our current
4581                                  *   block range, we should increment the
4582                                  *   reserved clusters count so that when the
4583                                  *   remaining blocks finally gets written, we
4584                                  *   could claim them.
4585                                  */
4586                                 dquot_reserve_block(inode,
4587                                                 EXT4_C2B(sbi, reservation));
4588                                 spin_lock(&ei->i_block_reservation_lock);
4589                                 ei->i_reserved_data_blocks += reservation;
4590                                 spin_unlock(&ei->i_block_reservation_lock);
4591                         }
4592                         /*
4593                          * We will claim quota for all newly allocated blocks.
4594                          * We're updating the reserved space *after* the
4595                          * correction above so we do not accidentally free
4596                          * all the metadata reservation because we might
4597                          * actually need it later on.
4598                          */
4599                         ext4_da_update_reserve_space(inode, allocated_clusters,
4600                                                         1);
4601                 }
4602         }
4603
4604         /*
4605          * Cache the extent and update transaction to commit on fdatasync only
4606          * when it is _not_ an unwritten extent.
4607          */
4608         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4609                 ext4_update_inode_fsync_trans(handle, inode, 1);
4610         else
4611                 ext4_update_inode_fsync_trans(handle, inode, 0);
4612 out:
4613         if (allocated > map->m_len)
4614                 allocated = map->m_len;
4615         ext4_ext_show_leaf(inode, path);
4616         map->m_flags |= EXT4_MAP_MAPPED;
4617         map->m_pblk = newblock;
4618         map->m_len = allocated;
4619 out2:
4620         if (path) {
4621                 ext4_ext_drop_refs(path);
4622                 kfree(path);
4623         }
4624
4625         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4626                                        err ? err : allocated);
4627         ext4_es_lru_add(inode);
4628         return err ? err : allocated;
4629 }
4630
4631 void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4632 {
4633         struct super_block *sb = inode->i_sb;
4634         ext4_lblk_t last_block;
4635         int err = 0;
4636
4637         /*
4638          * TODO: optimization is possible here.
4639          * Probably we need not scan at all,
4640          * because page truncation is enough.
4641          */
4642
4643         /* we have to know where to truncate from in crash case */
4644         EXT4_I(inode)->i_disksize = inode->i_size;
4645         ext4_mark_inode_dirty(handle, inode);
4646
4647         last_block = (inode->i_size + sb->s_blocksize - 1)
4648                         >> EXT4_BLOCK_SIZE_BITS(sb);
4649 retry:
4650         err = ext4_es_remove_extent(inode, last_block,
4651                                     EXT_MAX_BLOCKS - last_block);
4652         if (err == -ENOMEM) {
4653                 cond_resched();
4654                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4655                 goto retry;
4656         }
4657         if (err) {
4658                 ext4_std_error(inode->i_sb, err);
4659                 return;
4660         }
4661         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4662         ext4_std_error(inode->i_sb, err);
4663 }
4664
4665 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4666                                   ext4_lblk_t len, 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
4676         map.m_lblk = offset;
4677         /*
4678          * Don't normalize the request if it can fit in one extent so
4679          * that it doesn't get unnecessarily split into multiple
4680          * extents.
4681          */
4682         if (len <= EXT_UNWRITTEN_MAX_LEN)
4683                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4684
4685         /*
4686          * credits to insert 1 extent into extent tree
4687          */
4688         credits = ext4_chunk_trans_blocks(inode, len);
4689
4690 retry:
4691         while (ret >= 0 && ret < len) {
4692                 map.m_lblk = map.m_lblk + ret;
4693                 map.m_len = len = len - ret;
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                 ret2 = ext4_journal_stop(handle);
4711                 if (ret2)
4712                         break;
4713         }
4714         if (ret == -ENOSPC &&
4715                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4716                 ret = 0;
4717                 goto retry;
4718         }
4719
4720         return ret > 0 ? ret2 : ret;
4721 }
4722
4723 static long ext4_zero_range(struct file *file, loff_t offset,
4724                             loff_t len, int mode)
4725 {
4726         struct inode *inode = file_inode(file);
4727         handle_t *handle = NULL;
4728         unsigned int max_blocks;
4729         loff_t new_size = 0;
4730         int ret = 0;
4731         int flags;
4732         int partial;
4733         loff_t start, end;
4734         ext4_lblk_t lblk;
4735         struct address_space *mapping = inode->i_mapping;
4736         unsigned int blkbits = inode->i_blkbits;
4737
4738         trace_ext4_zero_range(inode, offset, len, mode);
4739
4740         if (!S_ISREG(inode->i_mode))
4741                 return -EINVAL;
4742
4743         /* Call ext4_force_commit to flush all data in case of data=journal. */
4744         if (ext4_should_journal_data(inode)) {
4745                 ret = ext4_force_commit(inode->i_sb);
4746                 if (ret)
4747                         return ret;
4748         }
4749
4750         /*
4751          * Write out all dirty pages to avoid race conditions
4752          * Then release them.
4753          */
4754         if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4755                 ret = filemap_write_and_wait_range(mapping, offset,
4756                                                    offset + len - 1);
4757                 if (ret)
4758                         return ret;
4759         }
4760
4761         /*
4762          * Round up offset. This is not fallocate, we neet to zero out
4763          * blocks, so convert interior block aligned part of the range to
4764          * unwritten and possibly manually zero out unaligned parts of the
4765          * range.
4766          */
4767         start = round_up(offset, 1 << blkbits);
4768         end = round_down((offset + len), 1 << blkbits);
4769
4770         if (start < offset || end > offset + len)
4771                 return -EINVAL;
4772         partial = (offset + len) & ((1 << blkbits) - 1);
4773
4774         lblk = start >> blkbits;
4775         max_blocks = (end >> blkbits);
4776         if (max_blocks < lblk)
4777                 max_blocks = 0;
4778         else
4779                 max_blocks -= lblk;
4780
4781         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT |
4782                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN;
4783         if (mode & FALLOC_FL_KEEP_SIZE)
4784                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4785
4786         mutex_lock(&inode->i_mutex);
4787
4788         /*
4789          * Indirect files do not support unwritten extnets
4790          */
4791         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4792                 ret = -EOPNOTSUPP;
4793                 goto out_mutex;
4794         }
4795
4796         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4797              offset + len > i_size_read(inode)) {
4798                 new_size = offset + len;
4799                 ret = inode_newsize_ok(inode, new_size);
4800                 if (ret)
4801                         goto out_mutex;
4802                 /*
4803                  * If we have a partial block after EOF we have to allocate
4804                  * the entire block.
4805                  */
4806                 if (partial)
4807                         max_blocks += 1;
4808         }
4809
4810         if (max_blocks > 0) {
4811
4812                 /* Now release the pages and zero block aligned part of pages*/
4813                 truncate_pagecache_range(inode, start, end - 1);
4814
4815                 /* Wait all existing dio workers, newcomers will block on i_mutex */
4816                 ext4_inode_block_unlocked_dio(inode);
4817                 inode_dio_wait(inode);
4818
4819                 /*
4820                  * Remove entire range from the extent status tree.
4821                  */
4822                 ret = ext4_es_remove_extent(inode, lblk, max_blocks);
4823                 if (ret)
4824                         goto out_dio;
4825
4826                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, flags,
4827                                              mode);
4828                 if (ret)
4829                         goto out_dio;
4830         }
4831
4832         handle = ext4_journal_start(inode, EXT4_HT_MISC, 4);
4833         if (IS_ERR(handle)) {
4834                 ret = PTR_ERR(handle);
4835                 ext4_std_error(inode->i_sb, ret);
4836                 goto out_dio;
4837         }
4838
4839         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4840
4841         if (new_size) {
4842                 if (new_size > i_size_read(inode))
4843                         i_size_write(inode, new_size);
4844                 if (new_size > EXT4_I(inode)->i_disksize)
4845                         ext4_update_i_disksize(inode, new_size);
4846         } else {
4847                 /*
4848                 * Mark that we allocate beyond EOF so the subsequent truncate
4849                 * can proceed even if the new size is the same as i_size.
4850                 */
4851                 if ((offset + len) > i_size_read(inode))
4852                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4853         }
4854
4855         ext4_mark_inode_dirty(handle, inode);
4856
4857         /* Zero out partial block at the edges of the range */
4858         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4859
4860         if (file->f_flags & O_SYNC)
4861                 ext4_handle_sync(handle);
4862
4863         ext4_journal_stop(handle);
4864 out_dio:
4865         ext4_inode_resume_unlocked_dio(inode);
4866 out_mutex:
4867         mutex_unlock(&inode->i_mutex);
4868         return ret;
4869 }
4870
4871 /*
4872  * preallocate space for a file. This implements ext4's fallocate file
4873  * operation, which gets called from sys_fallocate system call.
4874  * For block-mapped files, posix_fallocate should fall back to the method
4875  * of writing zeroes to the required new blocks (the same behavior which is
4876  * expected for file systems which do not support fallocate() system call).
4877  */
4878 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4879 {
4880         struct inode *inode = file_inode(file);
4881         handle_t *handle;
4882         loff_t new_size = 0;
4883         unsigned int max_blocks;
4884         int ret = 0;
4885         int flags;
4886         ext4_lblk_t lblk;
4887         struct timespec tv;
4888         unsigned int blkbits = inode->i_blkbits;
4889
4890         /* Return error if mode is not supported */
4891         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4892                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
4893                 return -EOPNOTSUPP;
4894
4895         if (mode & FALLOC_FL_PUNCH_HOLE)
4896                 return ext4_punch_hole(inode, offset, len);
4897
4898         ret = ext4_convert_inline_data(inode);
4899         if (ret)
4900                 return ret;
4901
4902         /*
4903          * currently supporting (pre)allocate mode for extent-based
4904          * files _only_
4905          */
4906         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4907                 return -EOPNOTSUPP;
4908
4909         if (mode & FALLOC_FL_COLLAPSE_RANGE)
4910                 return ext4_collapse_range(inode, offset, len);
4911
4912         if (mode & FALLOC_FL_ZERO_RANGE)
4913                 return ext4_zero_range(file, offset, len, mode);
4914
4915         trace_ext4_fallocate_enter(inode, offset, len, mode);
4916         lblk = offset >> blkbits;
4917         /*
4918          * We can't just convert len to max_blocks because
4919          * If blocksize = 4096 offset = 3072 and len = 2048
4920          */
4921         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4922                 - lblk;
4923
4924         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4925         if (mode & FALLOC_FL_KEEP_SIZE)
4926                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4927
4928         mutex_lock(&inode->i_mutex);
4929
4930         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4931              offset + len > i_size_read(inode)) {
4932                 new_size = offset + len;
4933                 ret = inode_newsize_ok(inode, new_size);
4934                 if (ret)
4935                         goto out;
4936         }
4937
4938         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, flags, mode);
4939         if (ret)
4940                 goto out;
4941
4942         handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
4943         if (IS_ERR(handle))
4944                 goto out;
4945
4946         tv = inode->i_ctime = ext4_current_time(inode);
4947
4948         if (new_size) {
4949                 if (new_size > i_size_read(inode)) {
4950                         i_size_write(inode, new_size);
4951                         inode->i_mtime = tv;
4952                 }
4953                 if (new_size > EXT4_I(inode)->i_disksize)
4954                         ext4_update_i_disksize(inode, new_size);
4955         } else {
4956                 /*
4957                 * Mark that we allocate beyond EOF so the subsequent truncate
4958                 * can proceed even if the new size is the same as i_size.
4959                 */
4960                 if ((offset + len) > i_size_read(inode))
4961                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4962         }
4963         ext4_mark_inode_dirty(handle, inode);
4964         if (file->f_flags & O_SYNC)
4965                 ext4_handle_sync(handle);
4966
4967         ext4_journal_stop(handle);
4968 out:
4969         mutex_unlock(&inode->i_mutex);
4970         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4971         return ret;
4972 }
4973
4974 /*
4975  * This function convert a range of blocks to written extents
4976  * The caller of this function will pass the start offset and the size.
4977  * all unwritten extents within this range will be converted to
4978  * written extents.
4979  *
4980  * This function is called from the direct IO end io call back
4981  * function, to convert the fallocated extents after IO is completed.
4982  * Returns 0 on success.
4983  */
4984 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4985                                    loff_t offset, ssize_t len)
4986 {
4987         unsigned int max_blocks;
4988         int ret = 0;
4989         int ret2 = 0;
4990         struct ext4_map_blocks map;
4991         unsigned int credits, blkbits = inode->i_blkbits;
4992
4993         map.m_lblk = offset >> blkbits;
4994         /*
4995          * We can't just convert len to max_blocks because
4996          * If blocksize = 4096 offset = 3072 and len = 2048
4997          */
4998         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
4999                       map.m_lblk);
5000         /*
5001          * This is somewhat ugly but the idea is clear: When transaction is
5002          * reserved, everything goes into it. Otherwise we rather start several
5003          * smaller transactions for conversion of each extent separately.
5004          */
5005         if (handle) {
5006                 handle = ext4_journal_start_reserved(handle,
5007                                                      EXT4_HT_EXT_CONVERT);
5008                 if (IS_ERR(handle))
5009                         return PTR_ERR(handle);
5010                 credits = 0;
5011         } else {
5012                 /*
5013                  * credits to insert 1 extent into extent tree
5014                  */
5015                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5016         }
5017         while (ret >= 0 && ret < max_blocks) {
5018                 map.m_lblk += ret;
5019                 map.m_len = (max_blocks -= ret);
5020                 if (credits) {
5021                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5022                                                     credits);
5023                         if (IS_ERR(handle)) {
5024                                 ret = PTR_ERR(handle);
5025                                 break;
5026                         }
5027                 }
5028                 ret = ext4_map_blocks(handle, inode, &map,
5029                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5030                 if (ret <= 0)
5031                         ext4_warning(inode->i_sb,
5032                                      "inode #%lu: block %u: len %u: "
5033                                      "ext4_ext_map_blocks returned %d",
5034                                      inode->i_ino, map.m_lblk,
5035                                      map.m_len, ret);
5036                 ext4_mark_inode_dirty(handle, inode);
5037                 if (credits)
5038                         ret2 = ext4_journal_stop(handle);
5039                 if (ret <= 0 || ret2)
5040                         break;
5041         }
5042         if (!credits)
5043                 ret2 = ext4_journal_stop(handle);
5044         return ret > 0 ? ret2 : ret;
5045 }
5046
5047 /*
5048  * If newes is not existing extent (newes->ec_pblk equals zero) find
5049  * delayed extent at start of newes and update newes accordingly and
5050  * return start of the next delayed extent.
5051  *
5052  * If newes is existing extent (newes->ec_pblk is not equal zero)
5053  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5054  * extent found. Leave newes unmodified.
5055  */
5056 static int ext4_find_delayed_extent(struct inode *inode,
5057                                     struct extent_status *newes)
5058 {
5059         struct extent_status es;
5060         ext4_lblk_t block, next_del;
5061
5062         if (newes->es_pblk == 0) {
5063                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5064                                 newes->es_lblk + newes->es_len - 1, &es);
5065
5066                 /*
5067                  * No extent in extent-tree contains block @newes->es_pblk,
5068                  * then the block may stay in 1)a hole or 2)delayed-extent.
5069                  */
5070                 if (es.es_len == 0)
5071                         /* A hole found. */
5072                         return 0;
5073
5074                 if (es.es_lblk > newes->es_lblk) {
5075                         /* A hole found. */
5076                         newes->es_len = min(es.es_lblk - newes->es_lblk,
5077                                             newes->es_len);
5078                         return 0;
5079                 }
5080
5081                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5082         }
5083
5084         block = newes->es_lblk + newes->es_len;
5085         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5086         if (es.es_len == 0)
5087                 next_del = EXT_MAX_BLOCKS;
5088         else
5089                 next_del = es.es_lblk;
5090
5091         return next_del;
5092 }
5093 /* fiemap flags we can handle specified here */
5094 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5095
5096 static int ext4_xattr_fiemap(struct inode *inode,
5097                                 struct fiemap_extent_info *fieinfo)
5098 {
5099         __u64 physical = 0;
5100         __u64 length;
5101         __u32 flags = FIEMAP_EXTENT_LAST;
5102         int blockbits = inode->i_sb->s_blocksize_bits;
5103         int error = 0;
5104
5105         /* in-inode? */
5106         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5107                 struct ext4_iloc iloc;
5108                 int offset;     /* offset of xattr in inode */
5109
5110                 error = ext4_get_inode_loc(inode, &iloc);
5111                 if (error)
5112                         return error;
5113                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5114                 offset = EXT4_GOOD_OLD_INODE_SIZE +
5115                                 EXT4_I(inode)->i_extra_isize;
5116                 physical += offset;
5117                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5118                 flags |= FIEMAP_EXTENT_DATA_INLINE;
5119                 brelse(iloc.bh);
5120         } else { /* external block */
5121                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5122                 length = inode->i_sb->s_blocksize;
5123         }
5124
5125         if (physical)
5126                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5127                                                 length, flags);
5128         return (error < 0 ? error : 0);
5129 }
5130
5131 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5132                 __u64 start, __u64 len)
5133 {
5134         ext4_lblk_t start_blk;
5135         int error = 0;
5136
5137         if (ext4_has_inline_data(inode)) {
5138                 int has_inline = 1;
5139
5140                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline);
5141
5142                 if (has_inline)
5143                         return error;
5144         }
5145
5146         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5147                 error = ext4_ext_precache(inode);
5148                 if (error)
5149                         return error;
5150         }
5151
5152         /* fallback to generic here if not in extents fmt */
5153         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5154                 return generic_block_fiemap(inode, fieinfo, start, len,
5155                         ext4_get_block);
5156
5157         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5158                 return -EBADR;
5159
5160         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5161                 error = ext4_xattr_fiemap(inode, fieinfo);
5162         } else {
5163                 ext4_lblk_t len_blks;
5164                 __u64 last_blk;
5165
5166                 start_blk = start >> inode->i_sb->s_blocksize_bits;
5167                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5168                 if (last_blk >= EXT_MAX_BLOCKS)
5169                         last_blk = EXT_MAX_BLOCKS-1;
5170                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5171
5172                 /*
5173                  * Walk the extent tree gathering extent information
5174                  * and pushing extents back to the user.
5175                  */
5176                 error = ext4_fill_fiemap_extents(inode, start_blk,
5177                                                  len_blks, fieinfo);
5178         }
5179         ext4_es_lru_add(inode);
5180         return error;
5181 }
5182
5183 /*
5184  * ext4_access_path:
5185  * Function to access the path buffer for marking it dirty.
5186  * It also checks if there are sufficient credits left in the journal handle
5187  * to update path.
5188  */
5189 static int
5190 ext4_access_path(handle_t *handle, struct inode *inode,
5191                 struct ext4_ext_path *path)
5192 {
5193         int credits, err;
5194
5195         if (!ext4_handle_valid(handle))
5196                 return 0;
5197
5198         /*
5199          * Check if need to extend journal credits
5200          * 3 for leaf, sb, and inode plus 2 (bmap and group
5201          * descriptor) for each block group; assume two block
5202          * groups
5203          */
5204         if (handle->h_buffer_credits < 7) {
5205                 credits = ext4_writepage_trans_blocks(inode);
5206                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5207                 /* EAGAIN is success */
5208                 if (err && err != -EAGAIN)
5209                         return err;
5210         }
5211
5212         err = ext4_ext_get_access(handle, inode, path);
5213         return err;
5214 }
5215
5216 /*
5217  * ext4_ext_shift_path_extents:
5218  * Shift the extents of a path structure lying between path[depth].p_ext
5219  * and EXT_LAST_EXTENT(path[depth].p_hdr) downwards, by subtracting shift
5220  * from starting block for each extent.
5221  */
5222 static int
5223 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5224                             struct inode *inode, handle_t *handle,
5225                             ext4_lblk_t *start)
5226 {
5227         int depth, err = 0;
5228         struct ext4_extent *ex_start, *ex_last;
5229         bool update = 0;
5230         depth = path->p_depth;
5231
5232         while (depth >= 0) {
5233                 if (depth == path->p_depth) {
5234                         ex_start = path[depth].p_ext;
5235                         if (!ex_start)
5236                                 return -EIO;
5237
5238                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5239                         if (!ex_last)
5240                                 return -EIO;
5241
5242                         err = ext4_access_path(handle, inode, path + depth);
5243                         if (err)
5244                                 goto out;
5245
5246                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5247                                 update = 1;
5248
5249                         *start = le32_to_cpu(ex_last->ee_block) +
5250                                 ext4_ext_get_actual_len(ex_last);
5251
5252                         while (ex_start <= ex_last) {
5253                                 le32_add_cpu(&ex_start->ee_block, -shift);
5254                                 /* Try to merge to the left. */
5255                                 if ((ex_start >
5256                                      EXT_FIRST_EXTENT(path[depth].p_hdr)) &&
5257                                     ext4_ext_try_to_merge_right(inode,
5258                                                         path, ex_start - 1))
5259                                         ex_last--;
5260                                 else
5261                                         ex_start++;
5262                         }
5263                         err = ext4_ext_dirty(handle, inode, path + depth);
5264                         if (err)
5265                                 goto out;
5266
5267                         if (--depth < 0 || !update)
5268                                 break;
5269                 }
5270
5271                 /* Update index too */
5272                 err = ext4_access_path(handle, inode, path + depth);
5273                 if (err)
5274                         goto out;
5275
5276                 le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5277                 err = ext4_ext_dirty(handle, inode, path + depth);
5278                 if (err)
5279                         goto out;
5280
5281                 /* we are done if current index is not a starting index */
5282                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5283                         break;
5284
5285                 depth--;
5286         }
5287
5288 out:
5289         return err;
5290 }
5291
5292 /*
5293  * ext4_ext_shift_extents:
5294  * All the extents which lies in the range from start to the last allocated
5295  * block for the file are shifted downwards by shift blocks.
5296  * On success, 0 is returned, error otherwise.
5297  */
5298 static int
5299 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5300                        ext4_lblk_t start, ext4_lblk_t shift)
5301 {
5302         struct ext4_ext_path *path;
5303         int ret = 0, depth;
5304         struct ext4_extent *extent;
5305         ext4_lblk_t stop_block, current_block;
5306         ext4_lblk_t ex_start, ex_end;
5307
5308         /* Let path point to the last extent */
5309         path = ext4_ext_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
5310         if (IS_ERR(path))
5311                 return PTR_ERR(path);
5312
5313         depth = path->p_depth;
5314         extent = path[depth].p_ext;
5315         if (!extent) {
5316                 ext4_ext_drop_refs(path);
5317                 kfree(path);
5318                 return ret;
5319         }
5320
5321         stop_block = le32_to_cpu(extent->ee_block) +
5322                         ext4_ext_get_actual_len(extent);
5323         ext4_ext_drop_refs(path);
5324         kfree(path);
5325
5326         /* Nothing to shift, if hole is at the end of file */
5327         if (start >= stop_block)
5328                 return ret;
5329
5330         /*
5331          * Don't start shifting extents until we make sure the hole is big
5332          * enough to accomodate the shift.
5333          */
5334         path = ext4_ext_find_extent(inode, start - 1, NULL, 0);
5335         if (IS_ERR(path))
5336                 return PTR_ERR(path);
5337         depth = path->p_depth;
5338         extent =  path[depth].p_ext;
5339         if (extent) {
5340                 ex_start = le32_to_cpu(extent->ee_block);
5341                 ex_end = le32_to_cpu(extent->ee_block) +
5342                         ext4_ext_get_actual_len(extent);
5343         } else {
5344                 ex_start = 0;
5345                 ex_end = 0;
5346         }
5347         ext4_ext_drop_refs(path);
5348         kfree(path);
5349
5350         if ((start == ex_start && shift > ex_start) ||
5351             (shift > start - ex_end))
5352                 return -EINVAL;
5353
5354         /* Its safe to start updating extents */
5355         while (start < stop_block) {
5356                 path = ext4_ext_find_extent(inode, start, NULL, 0);
5357                 if (IS_ERR(path))
5358                         return PTR_ERR(path);
5359                 depth = path->p_depth;
5360                 extent = path[depth].p_ext;
5361                 if (!extent) {
5362                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5363                                          (unsigned long) start);
5364                         return -EIO;
5365                 }
5366
5367                 current_block = le32_to_cpu(extent->ee_block);
5368                 if (start > current_block) {
5369                         /* Hole, move to the next extent */
5370                         ret = mext_next_extent(inode, path, &extent);
5371                         if (ret != 0) {
5372                                 ext4_ext_drop_refs(path);
5373                                 kfree(path);
5374                                 if (ret == 1)
5375                                         ret = 0;
5376                                 break;
5377                         }
5378                 }
5379                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5380                                 handle, &start);
5381                 ext4_ext_drop_refs(path);
5382                 kfree(path);
5383                 if (ret)
5384                         break;
5385         }
5386
5387         return ret;
5388 }
5389
5390 /*
5391  * ext4_collapse_range:
5392  * This implements the fallocate's collapse range functionality for ext4
5393  * Returns: 0 and non-zero on error.
5394  */
5395 int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5396 {
5397         struct super_block *sb = inode->i_sb;
5398         ext4_lblk_t punch_start, punch_stop;
5399         handle_t *handle;
5400         unsigned int credits;
5401         loff_t new_size, ioffset;
5402         int ret;
5403
5404         /* Collapse range works only on fs block size aligned offsets. */
5405         if (offset & (EXT4_BLOCK_SIZE(sb) - 1) ||
5406             len & (EXT4_BLOCK_SIZE(sb) - 1))
5407                 return -EINVAL;
5408
5409         if (!S_ISREG(inode->i_mode))
5410                 return -EINVAL;
5411
5412         if (EXT4_SB(inode->i_sb)->s_cluster_ratio > 1)
5413                 return -EOPNOTSUPP;
5414
5415         trace_ext4_collapse_range(inode, offset, len);
5416
5417         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5418         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5419
5420         /* Call ext4_force_commit to flush all data in case of data=journal. */
5421         if (ext4_should_journal_data(inode)) {
5422                 ret = ext4_force_commit(inode->i_sb);
5423                 if (ret)
5424                         return ret;
5425         }
5426
5427         /*
5428          * Need to round down offset to be aligned with page size boundary
5429          * for page size > block size.
5430          */
5431         ioffset = round_down(offset, PAGE_SIZE);
5432
5433         /* Write out all dirty pages */
5434         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5435                                            LLONG_MAX);
5436         if (ret)
5437                 return ret;
5438
5439         /* Take mutex lock */
5440         mutex_lock(&inode->i_mutex);
5441
5442         /*
5443          * There is no need to overlap collapse range with EOF, in which case
5444          * it is effectively a truncate operation
5445          */
5446         if (offset + len >= i_size_read(inode)) {
5447                 ret = -EINVAL;
5448                 goto out_mutex;
5449         }
5450
5451         /* Currently just for extent based files */
5452         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5453                 ret = -EOPNOTSUPP;
5454                 goto out_mutex;
5455         }
5456
5457         truncate_pagecache(inode, ioffset);
5458
5459         /* Wait for existing dio to complete */
5460         ext4_inode_block_unlocked_dio(inode);
5461         inode_dio_wait(inode);
5462
5463         credits = ext4_writepage_trans_blocks(inode);
5464         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5465         if (IS_ERR(handle)) {
5466                 ret = PTR_ERR(handle);
5467                 goto out_dio;
5468         }
5469
5470         down_write(&EXT4_I(inode)->i_data_sem);
5471         ext4_discard_preallocations(inode);
5472
5473         ret = ext4_es_remove_extent(inode, punch_start,
5474                                     EXT_MAX_BLOCKS - punch_start);
5475         if (ret) {
5476                 up_write(&EXT4_I(inode)->i_data_sem);
5477                 goto out_stop;
5478         }
5479
5480         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5481         if (ret) {
5482                 up_write(&EXT4_I(inode)->i_data_sem);
5483                 goto out_stop;
5484         }
5485         ext4_discard_preallocations(inode);
5486
5487         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5488                                      punch_stop - punch_start);
5489         if (ret) {
5490                 up_write(&EXT4_I(inode)->i_data_sem);
5491                 goto out_stop;
5492         }
5493
5494         new_size = i_size_read(inode) - len;
5495         i_size_write(inode, new_size);
5496         EXT4_I(inode)->i_disksize = new_size;
5497
5498         up_write(&EXT4_I(inode)->i_data_sem);
5499         if (IS_SYNC(inode))
5500                 ext4_handle_sync(handle);
5501         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5502         ext4_mark_inode_dirty(handle, inode);
5503
5504 out_stop:
5505         ext4_journal_stop(handle);
5506 out_dio:
5507         ext4_inode_resume_unlocked_dio(inode);
5508 out_mutex:
5509         mutex_unlock(&inode->i_mutex);
5510         return ret;
5511 }