fs/ext4/extents.c

   1 /*
   2  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3  * Written by Alex Tomas <alex@clusterfs.com>
   4  *
   5  * Architecture independence:
   6  *   Copyright (c) 2005, Bull S.A.
   7  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public Licens
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21  */
  22
  23 /*
  24  * Extents support for EXT4
  25  *
  26  * TODO:
  27  *   - ext4*_error() should be used in some situations
  28  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29  *   - smart tree reduction
  30  */
  31
  32 #include <linux/fs.h>
  33 #include <linux/time.h>
  34 #include <linux/jbd2.h>
  35 #include <linux/highuid.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/quotaops.h>
  38 #include <linux/string.h>
  39 #include <linux/slab.h>
  40 #include <linux/falloc.h>
  41 #include <asm/uaccess.h>
  42 #include <linux/fiemap.h>
  43 #include "ext4_jbd2.h"
  44 #include "ext4_extents.h"
  45 #include "xattr.h"
  46
  47 #include <trace/events/ext4.h>
  48
  49 /*
  50  * used by extent splitting.
  51  */
  52 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  53                                         due to ENOSPC */
  54 #define EXT4_EXT_MARK_UNINIT1   0x2  /* mark first half uninitialized */
  55 #define EXT4_EXT_MARK_UNINIT2   0x4  /* mark second half uninitialized */
  56
  57 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  58 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  59
  60 static __le32 ext4_extent_block_csum(struct inode *inode,
  61                                      struct ext4_extent_header *eh)
  62 {
  63         struct ext4_inode_info *ei = EXT4_I(inode);
  64         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  65         __u32 csum;
  66
  67         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  68                            EXT4_EXTENT_TAIL_OFFSET(eh));
  69         return cpu_to_le32(csum);
  70 }
  71
  72 static int ext4_extent_block_csum_verify(struct inode *inode,
  73                                          struct ext4_extent_header *eh)
  74 {
  75         struct ext4_extent_tail *et;
  76
  77         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  78                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  79                 return 1;
  80
  81         et = find_ext4_extent_tail(eh);
  82         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  83                 return 0;
  84         return 1;
  85 }
  86
  87 static void ext4_extent_block_csum_set(struct inode *inode,
  88                                        struct ext4_extent_header *eh)
  89 {
  90         struct ext4_extent_tail *et;
  91
  92         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  93                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  94                 return;
  95
  96         et = find_ext4_extent_tail(eh);
  97         et->et_checksum = ext4_extent_block_csum(inode, eh);
  98 }
  99
 100 static int ext4_split_extent(handle_t *handle,
 101                                 struct inode *inode,
 102                                 struct ext4_ext_path *path,
 103                                 struct ext4_map_blocks *map,
 104                                 int split_flag,
 105                                 int flags);
 106
 107 static int ext4_split_extent_at(handle_t *handle,
 108                              struct inode *inode,
 109                              struct ext4_ext_path *path,
 110                              ext4_lblk_t split,
 111                              int split_flag,
 112                              int flags);
 113
 114 static int ext4_find_delayed_extent(struct inode *inode,
 115                                     struct extent_status *newes);
 116
 117 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 118                                             struct inode *inode,
 119                                             int needed)
 120 {
 121         int err;
 122
 123         if (!ext4_handle_valid(handle))
 124                 return 0;
 125         if (handle->h_buffer_credits > needed)
 126                 return 0;
 127         err = ext4_journal_extend(handle, needed);
 128         if (err <= 0)
 129                 return err;
 130         err = ext4_truncate_restart_trans(handle, inode, needed);
 131         if (err == 0)
 132                 err = -EAGAIN;
 133
 134         return err;
 135 }
 136
 137 /*
 138  * could return:
 139  *  - EROFS
 140  *  - ENOMEM
 141  */
 142 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 143                                 struct ext4_ext_path *path)
 144 {
 145         if (path->p_bh) {
 146                 /* path points to block */
 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 #define ext4_ext_dirty(handle, inode, path) \
 161                 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
 162 static int __ext4_ext_dirty(const char *where, unsigned int line,
 163                             handle_t *handle, struct inode *inode,
 164                             struct ext4_ext_path *path)
 165 {
 166         int err;
 167         if (path->p_bh) {
 168                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 169                 /* path points to block */
 170                 err = __ext4_handle_dirty_metadata(where, line, handle,
 171                                                    inode, path->p_bh);
 172         } else {
 173                 /* path points to leaf/index in inode body */
 174                 err = ext4_mark_inode_dirty(handle, inode);
 175         }
 176         return err;
 177 }
 178
 179 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 180                               struct ext4_ext_path *path,
 181                               ext4_lblk_t block)
 182 {
 183         if (path) {
 184                 int depth = path->p_depth;
 185                 struct ext4_extent *ex;
 186
 187                 /*
 188                  * Try to predict block placement assuming that we are
 189                  * filling in a file which will eventually be
 190                  * non-sparse --- i.e., in the case of libbfd writing
 191                  * an ELF object sections out-of-order but in a way
 192                  * the eventually results in a contiguous object or
 193                  * executable file, or some database extending a table
 194                  * space file.  However, this is actually somewhat
 195                  * non-ideal if we are writing a sparse file such as
 196                  * qemu or KVM writing a raw image file that is going
 197                  * to stay fairly sparse, since it will end up
 198                  * fragmenting the file system's free space.  Maybe we
 199                  * should have some hueristics or some way to allow
 200                  * userspace to pass a hint to file system,
 201                  * especially if the latter case turns out to be
 202                  * common.
 203                  */
 204                 ex = path[depth].p_ext;
 205                 if (ex) {
 206                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 207                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 208
 209                         if (block > ext_block)
 210                                 return ext_pblk + (block - ext_block);
 211                         else
 212                                 return ext_pblk - (ext_block - block);
 213                 }
 214
 215                 /* it looks like index is empty;
 216                  * try to find starting block from index itself */
 217                 if (path[depth].p_bh)
 218                         return path[depth].p_bh->b_blocknr;
 219         }
 220
 221         /* OK. use inode's group */
 222         return ext4_inode_to_goal_block(inode);
 223 }
 224
 225 /*
 226  * Allocation for a meta data block
 227  */
 228 static ext4_fsblk_t
 229 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 230                         struct ext4_ext_path *path,
 231                         struct ext4_extent *ex, int *err, unsigned int flags)
 232 {
 233         ext4_fsblk_t goal, newblock;
 234
 235         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 236         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 237                                         NULL, err);
 238         return newblock;
 239 }
 240
 241 static inline int ext4_ext_space_block(struct inode *inode, int check)
 242 {
 243         int size;
 244
 245         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 246                         / sizeof(struct ext4_extent);
 247 #ifdef AGGRESSIVE_TEST
 248         if (!check && size > 6)
 249                 size = 6;
 250 #endif
 251         return size;
 252 }
 253
 254 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 255 {
 256         int size;
 257
 258         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 259                         / sizeof(struct ext4_extent_idx);
 260 #ifdef AGGRESSIVE_TEST
 261         if (!check && size > 5)
 262                 size = 5;
 263 #endif
 264         return size;
 265 }
 266
 267 static inline int ext4_ext_space_root(struct inode *inode, int check)
 268 {
 269         int size;
 270
 271         size = sizeof(EXT4_I(inode)->i_data);
 272         size -= sizeof(struct ext4_extent_header);
 273         size /= sizeof(struct ext4_extent);
 274 #ifdef AGGRESSIVE_TEST
 275         if (!check && size > 3)
 276                 size = 3;
 277 #endif
 278         return size;
 279 }
 280
 281 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 282 {
 283         int size;
 284
 285         size = sizeof(EXT4_I(inode)->i_data);
 286         size -= sizeof(struct ext4_extent_header);
 287         size /= sizeof(struct ext4_extent_idx);
 288 #ifdef AGGRESSIVE_TEST
 289         if (!check && size > 4)
 290                 size = 4;
 291 #endif
 292         return size;
 293 }
 294
 295 /*
 296  * Calculate the number of metadata blocks needed
 297  * to allocate @blocks
 298  * Worse case is one block per extent
 299  */
 300 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 301 {
 302         struct ext4_inode_info *ei = EXT4_I(inode);
 303         int idxs;
 304
 305         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 306                 / sizeof(struct ext4_extent_idx));
 307
 308         /*
 309          * If the new delayed allocation block is contiguous with the
 310          * previous da block, it can share index blocks with the
 311          * previous block, so we only need to allocate a new index
 312          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 313          * an additional index block, and at ldxs**3 blocks, yet
 314          * another index blocks.
 315          */
 316         if (ei->i_da_metadata_calc_len &&
 317             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 318                 int num = 0;
 319
 320                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 321                         num++;
 322                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 323                         num++;
 324                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 325                         num++;
 326                         ei->i_da_metadata_calc_len = 0;
 327                 } else
 328                         ei->i_da_metadata_calc_len++;
 329                 ei->i_da_metadata_calc_last_lblock++;
 330                 return num;
 331         }
 332
 333         /*
 334          * In the worst case we need a new set of index blocks at
 335          * every level of the inode's extent tree.
 336          */
 337         ei->i_da_metadata_calc_len = 1;
 338         ei->i_da_metadata_calc_last_lblock = lblock;
 339         return ext_depth(inode) + 1;
 340 }
 341
 342 static int
 343 ext4_ext_max_entries(struct inode *inode, int depth)
 344 {
 345         int max;
 346
 347         if (depth == ext_depth(inode)) {
 348                 if (depth == 0)
 349                         max = ext4_ext_space_root(inode, 1);
 350                 else
 351                         max = ext4_ext_space_root_idx(inode, 1);
 352         } else {
 353                 if (depth == 0)
 354                         max = ext4_ext_space_block(inode, 1);
 355                 else
 356                         max = ext4_ext_space_block_idx(inode, 1);
 357         }
 358
 359         return max;
 360 }
 361
 362 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 363 {
 364         ext4_fsblk_t block = ext4_ext_pblock(ext);
 365         int len = ext4_ext_get_actual_len(ext);
 366
 367         if (len == 0)
 368                 return 0;
 369         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 370 }
 371
 372 static int ext4_valid_extent_idx(struct inode *inode,
 373                                 struct ext4_extent_idx *ext_idx)
 374 {
 375         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 376
 377         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 378 }
 379
 380 static int ext4_valid_extent_entries(struct inode *inode,
 381                                 struct ext4_extent_header *eh,
 382                                 int depth)
 383 {
 384         unsigned short entries;
 385         if (eh->eh_entries == 0)
 386                 return 1;
 387
 388         entries = le16_to_cpu(eh->eh_entries);
 389
 390         if (depth == 0) {
 391                 /* leaf entries */
 392                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 393                 while (entries) {
 394                         if (!ext4_valid_extent(inode, ext))
 395                                 return 0;
 396                         ext++;
 397                         entries--;
 398                 }
 399         } else {
 400                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 401                 while (entries) {
 402                         if (!ext4_valid_extent_idx(inode, ext_idx))
 403                                 return 0;
 404                         ext_idx++;
 405                         entries--;
 406                 }
 407         }
 408         return 1;
 409 }
 410
 411 static int __ext4_ext_check(const char *function, unsigned int line,
 412                             struct inode *inode, struct ext4_extent_header *eh,
 413                             int depth)
 414 {
 415         const char *error_msg;
 416         int max = 0;
 417
 418         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 419                 error_msg = "invalid magic";
 420                 goto corrupted;
 421         }
 422         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 423                 error_msg = "unexpected eh_depth";
 424                 goto corrupted;
 425         }
 426         if (unlikely(eh->eh_max == 0)) {
 427                 error_msg = "invalid eh_max";
 428                 goto corrupted;
 429         }
 430         max = ext4_ext_max_entries(inode, depth);
 431         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 432                 error_msg = "too large eh_max";
 433                 goto corrupted;
 434         }
 435         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 436                 error_msg = "invalid eh_entries";
 437                 goto corrupted;
 438         }
 439         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 440                 error_msg = "invalid extent entries";
 441                 goto corrupted;
 442         }
 443         /* Verify checksum on non-root extent tree nodes */
 444         if (ext_depth(inode) != depth &&
 445             !ext4_extent_block_csum_verify(inode, eh)) {
 446                 error_msg = "extent tree corrupted";
 447                 goto corrupted;
 448         }
 449         return 0;
 450
 451 corrupted:
 452         ext4_error_inode(inode, function, line, 0,
 453                         "bad header/extent: %s - magic %x, "
 454                         "entries %u, max %u(%u), depth %u(%u)",
 455                         error_msg, le16_to_cpu(eh->eh_magic),
 456                         le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 457                         max, le16_to_cpu(eh->eh_depth), depth);
 458
 459         return -EIO;
 460 }
 461
 462 #define ext4_ext_check(inode, eh, depth)        \
 463         __ext4_ext_check(__func__, __LINE__, inode, eh, depth)
 464
 465 int ext4_ext_check_inode(struct inode *inode)
 466 {
 467         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
 468 }
 469
 470 static int __ext4_ext_check_block(const char *function, unsigned int line,
 471                                   struct inode *inode,
 472                                   struct ext4_extent_header *eh,
 473                                   int depth,
 474                                   struct buffer_head *bh)
 475 {
 476         int ret;
 477
 478         if (buffer_verified(bh))
 479                 return 0;
 480         ret = ext4_ext_check(inode, eh, depth);
 481         if (ret)
 482                 return ret;
 483         set_buffer_verified(bh);
 484         return ret;
 485 }
 486
 487 #define ext4_ext_check_block(inode, eh, depth, bh)      \
 488         __ext4_ext_check_block(__func__, __LINE__, inode, eh, depth, bh)
 489
 490 #ifdef EXT_DEBUG
 491 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 492 {
 493         int k, l = path->p_depth;
 494
 495         ext_debug("path:");
 496         for (k = 0; k <= l; k++, path++) {
 497                 if (path->p_idx) {
 498                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 499                             ext4_idx_pblock(path->p_idx));
 500                 } else if (path->p_ext) {
 501                         ext_debug("  %d:[%d]%d:%llu ",
 502                                   le32_to_cpu(path->p_ext->ee_block),
 503                                   ext4_ext_is_uninitialized(path->p_ext),
 504                                   ext4_ext_get_actual_len(path->p_ext),
 505                                   ext4_ext_pblock(path->p_ext));
 506                 } else
 507                         ext_debug("  []");
 508         }
 509         ext_debug("\n");
 510 }
 511
 512 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 513 {
 514         int depth = ext_depth(inode);
 515         struct ext4_extent_header *eh;
 516         struct ext4_extent *ex;
 517         int i;
 518
 519         if (!path)
 520                 return;
 521
 522         eh = path[depth].p_hdr;
 523         ex = EXT_FIRST_EXTENT(eh);
 524
 525         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 526
 527         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 528                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 529                           ext4_ext_is_uninitialized(ex),
 530                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 531         }
 532         ext_debug("\n");
 533 }
 534
 535 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 536                         ext4_fsblk_t newblock, int level)
 537 {
 538         int depth = ext_depth(inode);
 539         struct ext4_extent *ex;
 540
 541         if (depth != level) {
 542                 struct ext4_extent_idx *idx;
 543                 idx = path[level].p_idx;
 544                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 545                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 546                                         le32_to_cpu(idx->ei_block),
 547                                         ext4_idx_pblock(idx),
 548                                         newblock);
 549                         idx++;
 550                 }
 551
 552                 return;
 553         }
 554
 555         ex = path[depth].p_ext;
 556         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 557                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 558                                 le32_to_cpu(ex->ee_block),
 559                                 ext4_ext_pblock(ex),
 560                                 ext4_ext_is_uninitialized(ex),
 561                                 ext4_ext_get_actual_len(ex),
 562                                 newblock);
 563                 ex++;
 564         }
 565 }
 566
 567 #else
 568 #define ext4_ext_show_path(inode, path)
 569 #define ext4_ext_show_leaf(inode, path)
 570 #define ext4_ext_show_move(inode, path, newblock, level)
 571 #endif
 572
 573 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 574 {
 575         int depth = path->p_depth;
 576         int i;
 577
 578         for (i = 0; i <= depth; i++, path++)
 579                 if (path->p_bh) {
 580                         brelse(path->p_bh);
 581                         path->p_bh = NULL;
 582                 }
 583 }
 584
 585 /*
 586  * ext4_ext_binsearch_idx:
 587  * binary search for the closest index of the given block
 588  * the header must be checked before calling this
 589  */
 590 static void
 591 ext4_ext_binsearch_idx(struct inode *inode,
 592                         struct ext4_ext_path *path, ext4_lblk_t block)
 593 {
 594         struct ext4_extent_header *eh = path->p_hdr;
 595         struct ext4_extent_idx *r, *l, *m;
 596
 597
 598         ext_debug("binsearch for %u(idx):  ", block);
 599
 600         l = EXT_FIRST_INDEX(eh) + 1;
 601         r = EXT_LAST_INDEX(eh);
 602         while (l <= r) {
 603                 m = l + (r - l) / 2;
 604                 if (block < le32_to_cpu(m->ei_block))
 605                         r = m - 1;
 606                 else
 607                         l = m + 1;
 608                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 609                                 m, le32_to_cpu(m->ei_block),
 610                                 r, le32_to_cpu(r->ei_block));
 611         }
 612
 613         path->p_idx = l - 1;
 614         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 615                   ext4_idx_pblock(path->p_idx));
 616
 617 #ifdef CHECK_BINSEARCH
 618         {
 619                 struct ext4_extent_idx *chix, *ix;
 620                 int k;
 621
 622                 chix = ix = EXT_FIRST_INDEX(eh);
 623                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 624                   if (k != 0 &&
 625                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 626                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 627                                        "first=0x%p\n", k,
 628                                        ix, EXT_FIRST_INDEX(eh));
 629                                 printk(KERN_DEBUG "%u <= %u\n",
 630                                        le32_to_cpu(ix->ei_block),
 631                                        le32_to_cpu(ix[-1].ei_block));
 632                         }
 633                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 634                                            <= le32_to_cpu(ix[-1].ei_block));
 635                         if (block < le32_to_cpu(ix->ei_block))
 636                                 break;
 637                         chix = ix;
 638                 }
 639                 BUG_ON(chix != path->p_idx);
 640         }
 641 #endif
 642
 643 }
 644
 645 /*
 646  * ext4_ext_binsearch:
 647  * binary search for closest extent of the given block
 648  * the header must be checked before calling this
 649  */
 650 static void
 651 ext4_ext_binsearch(struct inode *inode,
 652                 struct ext4_ext_path *path, ext4_lblk_t block)
 653 {
 654         struct ext4_extent_header *eh = path->p_hdr;
 655         struct ext4_extent *r, *l, *m;
 656
 657         if (eh->eh_entries == 0) {
 658                 /*
 659                  * this leaf is empty:
 660                  * we get such a leaf in split/add case
 661                  */
 662                 return;
 663         }
 664
 665         ext_debug("binsearch for %u:  ", block);
 666
 667         l = EXT_FIRST_EXTENT(eh) + 1;
 668         r = EXT_LAST_EXTENT(eh);
 669
 670         while (l <= r) {
 671                 m = l + (r - l) / 2;
 672                 if (block < le32_to_cpu(m->ee_block))
 673                         r = m - 1;
 674                 else
 675                         l = m + 1;
 676                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 677                                 m, le32_to_cpu(m->ee_block),
 678                                 r, le32_to_cpu(r->ee_block));
 679         }
 680
 681         path->p_ext = l - 1;
 682         ext_debug("  -> %d:%llu:[%d]%d ",
 683                         le32_to_cpu(path->p_ext->ee_block),
 684                         ext4_ext_pblock(path->p_ext),
 685                         ext4_ext_is_uninitialized(path->p_ext),
 686                         ext4_ext_get_actual_len(path->p_ext));
 687
 688 #ifdef CHECK_BINSEARCH
 689         {
 690                 struct ext4_extent *chex, *ex;
 691                 int k;
 692
 693                 chex = ex = EXT_FIRST_EXTENT(eh);
 694                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 695                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 696                                           <= le32_to_cpu(ex[-1].ee_block));
 697                         if (block < le32_to_cpu(ex->ee_block))
 698                                 break;
 699                         chex = ex;
 700                 }
 701                 BUG_ON(chex != path->p_ext);
 702         }
 703 #endif
 704
 705 }
 706
 707 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 708 {
 709         struct ext4_extent_header *eh;
 710
 711         eh = ext_inode_hdr(inode);
 712         eh->eh_depth = 0;
 713         eh->eh_entries = 0;
 714         eh->eh_magic = EXT4_EXT_MAGIC;
 715         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 716         ext4_mark_inode_dirty(handle, inode);
 717         return 0;
 718 }
 719
 720 struct ext4_ext_path *
 721 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 722                                         struct ext4_ext_path *path)
 723 {
 724         struct ext4_extent_header *eh;
 725         struct buffer_head *bh;
 726         short int depth, i, ppos = 0, alloc = 0;
 727         int ret;
 728
 729         eh = ext_inode_hdr(inode);
 730         depth = ext_depth(inode);
 731
 732         /* account possible depth increase */
 733         if (!path) {
 734                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 735                                 GFP_NOFS);
 736                 if (!path)
 737                         return ERR_PTR(-ENOMEM);
 738                 alloc = 1;
 739         }
 740         path[0].p_hdr = eh;
 741         path[0].p_bh = NULL;
 742
 743         i = depth;
 744         /* walk through the tree */
 745         while (i) {
 746                 ext_debug("depth %d: num %d, max %d\n",
 747                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 748
 749                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 750                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 751                 path[ppos].p_depth = i;
 752                 path[ppos].p_ext = NULL;
 753
 754                 bh = sb_getblk(inode->i_sb, path[ppos].p_block);
 755                 if (unlikely(!bh)) {
 756                         ret = -ENOMEM;
 757                         goto err;
 758                 }
 759                 if (!bh_uptodate_or_lock(bh)) {
 760                         trace_ext4_ext_load_extent(inode, block,
 761                                                 path[ppos].p_block);
 762                         ret = bh_submit_read(bh);
 763                         if (ret < 0) {
 764                                 put_bh(bh);
 765                                 goto err;
 766                         }
 767                 }
 768                 eh = ext_block_hdr(bh);
 769                 ppos++;
 770                 if (unlikely(ppos > depth)) {
 771                         put_bh(bh);
 772                         EXT4_ERROR_INODE(inode,
 773                                          "ppos %d > depth %d", ppos, depth);
 774                         ret = -EIO;
 775                         goto err;
 776                 }
 777                 path[ppos].p_bh = bh;
 778                 path[ppos].p_hdr = eh;
 779                 i--;
 780
 781                 ret = ext4_ext_check_block(inode, eh, i, bh);
 782                 if (ret < 0)
 783                         goto err;
 784         }
 785
 786         path[ppos].p_depth = i;
 787         path[ppos].p_ext = NULL;
 788         path[ppos].p_idx = NULL;
 789
 790         /* find extent */
 791         ext4_ext_binsearch(inode, path + ppos, block);
 792         /* if not an empty leaf */
 793         if (path[ppos].p_ext)
 794                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 795
 796         ext4_ext_show_path(inode, path);
 797
 798         return path;
 799
 800 err:
 801         ext4_ext_drop_refs(path);
 802         if (alloc)
 803                 kfree(path);
 804         return ERR_PTR(ret);
 805 }
 806
 807 /*
 808  * ext4_ext_insert_index:
 809  * insert new index [@logical;@ptr] into the block at @curp;
 810  * check where to insert: before @curp or after @curp
 811  */
 812 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 813                                  struct ext4_ext_path *curp,
 814                                  int logical, ext4_fsblk_t ptr)
 815 {
 816         struct ext4_extent_idx *ix;
 817         int len, err;
 818
 819         err = ext4_ext_get_access(handle, inode, curp);
 820         if (err)
 821                 return err;
 822
 823         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 824                 EXT4_ERROR_INODE(inode,
 825                                  "logical %d == ei_block %d!",
 826                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 827                 return -EIO;
 828         }
 829
 830         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 831                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 832                 EXT4_ERROR_INODE(inode,
 833                                  "eh_entries %d >= eh_max %d!",
 834                                  le16_to_cpu(curp->p_hdr->eh_entries),
 835                                  le16_to_cpu(curp->p_hdr->eh_max));
 836                 return -EIO;
 837         }
 838
 839         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 840                 /* insert after */
 841                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 842                 ix = curp->p_idx + 1;
 843         } else {
 844                 /* insert before */
 845                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 846                 ix = curp->p_idx;
 847         }
 848
 849         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 850         BUG_ON(len < 0);
 851         if (len > 0) {
 852                 ext_debug("insert new index %d: "
 853                                 "move %d indices from 0x%p to 0x%p\n",
 854                                 logical, len, ix, ix + 1);
 855                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 856         }
 857
 858         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 859                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 860                 return -EIO;
 861         }
 862
 863         ix->ei_block = cpu_to_le32(logical);
 864         ext4_idx_store_pblock(ix, ptr);
 865         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 866
 867         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 868                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 869                 return -EIO;
 870         }
 871
 872         err = ext4_ext_dirty(handle, inode, curp);
 873         ext4_std_error(inode->i_sb, err);
 874
 875         return err;
 876 }
 877
 878 /*
 879  * ext4_ext_split:
 880  * inserts new subtree into the path, using free index entry
 881  * at depth @at:
 882  * - allocates all needed blocks (new leaf and all intermediate index blocks)
 883  * - makes decision where to split
 884  * - moves remaining extents and index entries (right to the split point)
 885  *   into the newly allocated blocks
 886  * - initializes subtree
 887  */
 888 static int ext4_ext_split(handle_t *handle, struct inode *inode,
 889                           unsigned int flags,
 890                           struct ext4_ext_path *path,
 891                           struct ext4_extent *newext, int at)
 892 {
 893         struct buffer_head *bh = NULL;
 894         int depth = ext_depth(inode);
 895         struct ext4_extent_header *neh;
 896         struct ext4_extent_idx *fidx;
 897         int i = at, k, m, a;
 898         ext4_fsblk_t newblock, oldblock;
 899         __le32 border;
 900         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
 901         int err = 0;
 902
 903         /* make decision: where to split? */
 904         /* FIXME: now decision is simplest: at current extent */
 905
 906         /* if current leaf will be split, then we should use
 907          * border from split point */
 908         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
 909                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
 910                 return -EIO;
 911         }
 912         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
 913                 border = path[depth].p_ext[1].ee_block;
 914                 ext_debug("leaf will be split."
 915                                 " next leaf starts at %d\n",
 916                                   le32_to_cpu(border));
 917         } else {
 918                 border = newext->ee_block;
 919                 ext_debug("leaf will be added."
 920                                 " next leaf starts at %d\n",
 921                                 le32_to_cpu(border));
 922         }
 923
 924         /*
 925          * If error occurs, then we break processing
 926          * and mark filesystem read-only. index won't
 927          * be inserted and tree will be in consistent
 928          * state. Next mount will repair buffers too.
 929          */
 930
 931         /*
 932          * Get array to track all allocated blocks.
 933          * We need this to handle errors and free blocks
 934          * upon them.
 935          */
 936         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
 937         if (!ablocks)
 938                 return -ENOMEM;
 939
 940         /* allocate all needed blocks */
 941         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
 942         for (a = 0; a < depth - at; a++) {
 943                 newblock = ext4_ext_new_meta_block(handle, inode, path,
 944                                                    newext, &err, flags);
 945                 if (newblock == 0)
 946                         goto cleanup;
 947                 ablocks[a] = newblock;
 948         }
 949
 950         /* initialize new leaf */
 951         newblock = ablocks[--a];
 952         if (unlikely(newblock == 0)) {
 953                 EXT4_ERROR_INODE(inode, "newblock == 0!");
 954                 err = -EIO;
 955                 goto cleanup;
 956         }
 957         bh = sb_getblk(inode->i_sb, newblock);
 958         if (unlikely(!bh)) {
 959                 err = -ENOMEM;
 960                 goto cleanup;
 961         }
 962         lock_buffer(bh);
 963
 964         err = ext4_journal_get_create_access(handle, bh);
 965         if (err)
 966                 goto cleanup;
 967
 968         neh = ext_block_hdr(bh);
 969         neh->eh_entries = 0;
 970         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
 971         neh->eh_magic = EXT4_EXT_MAGIC;
 972         neh->eh_depth = 0;
 973
 974         /* move remainder of path[depth] to the new leaf */
 975         if (unlikely(path[depth].p_hdr->eh_entries !=
 976                      path[depth].p_hdr->eh_max)) {
 977                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
 978                                  path[depth].p_hdr->eh_entries,
 979                                  path[depth].p_hdr->eh_max);
 980                 err = -EIO;
 981                 goto cleanup;
 982         }
 983         /* start copy from next extent */
 984         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
 985         ext4_ext_show_move(inode, path, newblock, depth);
 986         if (m) {
 987                 struct ext4_extent *ex;
 988                 ex = EXT_FIRST_EXTENT(neh);
 989                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
 990                 le16_add_cpu(&neh->eh_entries, m);
 991         }
 992
 993         ext4_extent_block_csum_set(inode, neh);
 994         set_buffer_uptodate(bh);
 995         unlock_buffer(bh);
 996
 997         err = ext4_handle_dirty_metadata(handle, inode, bh);
 998         if (err)
 999                 goto cleanup;
1000         brelse(bh);
1001         bh = NULL;
1002
1003         /* correct old leaf */
1004         if (m) {
1005                 err = ext4_ext_get_access(handle, inode, path + depth);
1006                 if (err)
1007                         goto cleanup;
1008                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1009                 err = ext4_ext_dirty(handle, inode, path + depth);
1010                 if (err)
1011                         goto cleanup;
1012
1013         }
1014
1015         /* create intermediate indexes */
1016         k = depth - at - 1;
1017         if (unlikely(k < 0)) {
1018                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1019                 err = -EIO;
1020                 goto cleanup;
1021         }
1022         if (k)
1023                 ext_debug("create %d intermediate indices\n", k);
1024         /* insert new index into current index block */
1025         /* current depth stored in i var */
1026         i = depth - 1;
1027         while (k--) {
1028                 oldblock = newblock;
1029                 newblock = ablocks[--a];
1030                 bh = sb_getblk(inode->i_sb, newblock);
1031                 if (unlikely(!bh)) {
1032                         err = -ENOMEM;
1033                         goto cleanup;
1034                 }
1035                 lock_buffer(bh);
1036
1037                 err = ext4_journal_get_create_access(handle, bh);
1038                 if (err)
1039                         goto cleanup;
1040
1041                 neh = ext_block_hdr(bh);
1042                 neh->eh_entries = cpu_to_le16(1);
1043                 neh->eh_magic = EXT4_EXT_MAGIC;
1044                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1045                 neh->eh_depth = cpu_to_le16(depth - i);
1046                 fidx = EXT_FIRST_INDEX(neh);
1047                 fidx->ei_block = border;
1048                 ext4_idx_store_pblock(fidx, oldblock);
1049
1050                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1051                                 i, newblock, le32_to_cpu(border), oldblock);
1052
1053                 /* move remainder of path[i] to the new index block */
1054                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1055                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1056                         EXT4_ERROR_INODE(inode,
1057                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1058                                          le32_to_cpu(path[i].p_ext->ee_block));
1059                         err = -EIO;
1060                         goto cleanup;
1061                 }
1062                 /* start copy indexes */
1063                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1064                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1065                                 EXT_MAX_INDEX(path[i].p_hdr));
1066                 ext4_ext_show_move(inode, path, newblock, i);
1067                 if (m) {
1068                         memmove(++fidx, path[i].p_idx,
1069                                 sizeof(struct ext4_extent_idx) * m);
1070                         le16_add_cpu(&neh->eh_entries, m);
1071                 }
1072                 ext4_extent_block_csum_set(inode, neh);
1073                 set_buffer_uptodate(bh);
1074                 unlock_buffer(bh);
1075
1076                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1077                 if (err)
1078                         goto cleanup;
1079                 brelse(bh);
1080                 bh = NULL;
1081
1082                 /* correct old index */
1083                 if (m) {
1084                         err = ext4_ext_get_access(handle, inode, path + i);
1085                         if (err)
1086                                 goto cleanup;
1087                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1088                         err = ext4_ext_dirty(handle, inode, path + i);
1089                         if (err)
1090                                 goto cleanup;
1091                 }
1092
1093                 i--;
1094         }
1095
1096         /* insert new index */
1097         err = ext4_ext_insert_index(handle, inode, path + at,
1098                                     le32_to_cpu(border), newblock);
1099
1100 cleanup:
1101         if (bh) {
1102                 if (buffer_locked(bh))
1103                         unlock_buffer(bh);
1104                 brelse(bh);
1105         }
1106
1107         if (err) {
1108                 /* free all allocated blocks in error case */
1109                 for (i = 0; i < depth; i++) {
1110                         if (!ablocks[i])
1111                                 continue;
1112                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1113                                          EXT4_FREE_BLOCKS_METADATA);
1114                 }
1115         }
1116         kfree(ablocks);
1117
1118         return err;
1119 }
1120
1121 /*
1122  * ext4_ext_grow_indepth:
1123  * implements tree growing procedure:
1124  * - allocates new block
1125  * - moves top-level data (index block or leaf) into the new block
1126  * - initializes new top-level, creating index that points to the
1127  *   just created block
1128  */
1129 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1130                                  unsigned int flags,
1131                                  struct ext4_extent *newext)
1132 {
1133         struct ext4_extent_header *neh;
1134         struct buffer_head *bh;
1135         ext4_fsblk_t newblock;
1136         int err = 0;
1137
1138         newblock = ext4_ext_new_meta_block(handle, inode, NULL,
1139                 newext, &err, flags);
1140         if (newblock == 0)
1141                 return err;
1142
1143         bh = sb_getblk(inode->i_sb, newblock);
1144         if (unlikely(!bh))
1145                 return -ENOMEM;
1146         lock_buffer(bh);
1147
1148         err = ext4_journal_get_create_access(handle, bh);
1149         if (err) {
1150                 unlock_buffer(bh);
1151                 goto out;
1152         }
1153
1154         /* move top-level index/leaf into new block */
1155         memmove(bh->b_data, EXT4_I(inode)->i_data,
1156                 sizeof(EXT4_I(inode)->i_data));
1157
1158         /* set size of new block */
1159         neh = ext_block_hdr(bh);
1160         /* old root could have indexes or leaves
1161          * so calculate e_max right way */
1162         if (ext_depth(inode))
1163                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1164         else
1165                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1166         neh->eh_magic = EXT4_EXT_MAGIC;
1167         ext4_extent_block_csum_set(inode, neh);
1168         set_buffer_uptodate(bh);
1169         unlock_buffer(bh);
1170
1171         err = ext4_handle_dirty_metadata(handle, inode, bh);
1172         if (err)
1173                 goto out;
1174
1175         /* Update top-level index: num,max,pointer */
1176         neh = ext_inode_hdr(inode);
1177         neh->eh_entries = cpu_to_le16(1);
1178         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1179         if (neh->eh_depth == 0) {
1180                 /* Root extent block becomes index block */
1181                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1182                 EXT_FIRST_INDEX(neh)->ei_block =
1183                         EXT_FIRST_EXTENT(neh)->ee_block;
1184         }
1185         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1186                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1187                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1188                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1189
1190         le16_add_cpu(&neh->eh_depth, 1);
1191         ext4_mark_inode_dirty(handle, inode);
1192 out:
1193         brelse(bh);
1194
1195         return err;
1196 }
1197
1198 /*
1199  * ext4_ext_create_new_leaf:
1200  * finds empty index and adds new leaf.
1201  * if no free index is found, then it requests in-depth growing.
1202  */
1203 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1204                                     unsigned int flags,
1205                                     struct ext4_ext_path *path,
1206                                     struct ext4_extent *newext)
1207 {
1208         struct ext4_ext_path *curp;
1209         int depth, i, err = 0;
1210
1211 repeat:
1212         i = depth = ext_depth(inode);
1213
1214         /* walk up to the tree and look for free index entry */
1215         curp = path + depth;
1216         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1217                 i--;
1218                 curp--;
1219         }
1220
1221         /* we use already allocated block for index block,
1222          * so subsequent data blocks should be contiguous */
1223         if (EXT_HAS_FREE_INDEX(curp)) {
1224                 /* if we found index with free entry, then use that
1225                  * entry: create all needed subtree and add new leaf */
1226                 err = ext4_ext_split(handle, inode, flags, path, newext, i);
1227                 if (err)
1228                         goto out;
1229
1230                 /* refill path */
1231                 ext4_ext_drop_refs(path);
1232                 path = ext4_ext_find_extent(inode,
1233                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1234                                     path);
1235                 if (IS_ERR(path))
1236                         err = PTR_ERR(path);
1237         } else {
1238                 /* tree is full, time to grow in depth */
1239                 err = ext4_ext_grow_indepth(handle, inode, flags, newext);
1240                 if (err)
1241                         goto out;
1242
1243                 /* refill path */
1244                 ext4_ext_drop_refs(path);
1245                 path = ext4_ext_find_extent(inode,
1246                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1247                                     path);
1248                 if (IS_ERR(path)) {
1249                         err = PTR_ERR(path);
1250                         goto out;
1251                 }
1252
1253                 /*
1254                  * only first (depth 0 -> 1) produces free space;
1255                  * in all other cases we have to split the grown tree
1256                  */
1257                 depth = ext_depth(inode);
1258                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1259                         /* now we need to split */
1260                         goto repeat;
1261                 }
1262         }
1263
1264 out:
1265         return err;
1266 }
1267
1268 /*
1269  * search the closest allocated block to the left for *logical
1270  * and returns it at @logical + it's physical address at @phys
1271  * if *logical is the smallest allocated block, the function
1272  * returns 0 at @phys
1273  * return value contains 0 (success) or error code
1274  */
1275 static int ext4_ext_search_left(struct inode *inode,
1276                                 struct ext4_ext_path *path,
1277                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1278 {
1279         struct ext4_extent_idx *ix;
1280         struct ext4_extent *ex;
1281         int depth, ee_len;
1282
1283         if (unlikely(path == NULL)) {
1284                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1285                 return -EIO;
1286         }
1287         depth = path->p_depth;
1288         *phys = 0;
1289
1290         if (depth == 0 && path->p_ext == NULL)
1291                 return 0;
1292
1293         /* usually extent in the path covers blocks smaller
1294          * then *logical, but it can be that extent is the
1295          * first one in the file */
1296
1297         ex = path[depth].p_ext;
1298         ee_len = ext4_ext_get_actual_len(ex);
1299         if (*logical < le32_to_cpu(ex->ee_block)) {
1300                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1301                         EXT4_ERROR_INODE(inode,
1302                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1303                                          *logical, le32_to_cpu(ex->ee_block));
1304                         return -EIO;
1305                 }
1306                 while (--depth >= 0) {
1307                         ix = path[depth].p_idx;
1308                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1309                                 EXT4_ERROR_INODE(inode,
1310                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1311                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1312                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1313                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1314                                   depth);
1315                                 return -EIO;
1316                         }
1317                 }
1318                 return 0;
1319         }
1320
1321         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1322                 EXT4_ERROR_INODE(inode,
1323                                  "logical %d < ee_block %d + ee_len %d!",
1324                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1325                 return -EIO;
1326         }
1327
1328         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1329         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1330         return 0;
1331 }
1332
1333 /*
1334  * search the closest allocated block to the right for *logical
1335  * and returns it at @logical + it's physical address at @phys
1336  * if *logical is the largest allocated block, the function
1337  * returns 0 at @phys
1338  * return value contains 0 (success) or error code
1339  */
1340 static int ext4_ext_search_right(struct inode *inode,
1341                                  struct ext4_ext_path *path,
1342                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1343                                  struct ext4_extent **ret_ex)
1344 {
1345         struct buffer_head *bh = NULL;
1346         struct ext4_extent_header *eh;
1347         struct ext4_extent_idx *ix;
1348         struct ext4_extent *ex;
1349         ext4_fsblk_t block;
1350         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1351         int ee_len;
1352
1353         if (unlikely(path == NULL)) {
1354                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1355                 return -EIO;
1356         }
1357         depth = path->p_depth;
1358         *phys = 0;
1359
1360         if (depth == 0 && path->p_ext == NULL)
1361                 return 0;
1362
1363         /* usually extent in the path covers blocks smaller
1364          * then *logical, but it can be that extent is the
1365          * first one in the file */
1366
1367         ex = path[depth].p_ext;
1368         ee_len = ext4_ext_get_actual_len(ex);
1369         if (*logical < le32_to_cpu(ex->ee_block)) {
1370                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1371                         EXT4_ERROR_INODE(inode,
1372                                          "first_extent(path[%d].p_hdr) != ex",
1373                                          depth);
1374                         return -EIO;
1375                 }
1376                 while (--depth >= 0) {
1377                         ix = path[depth].p_idx;
1378                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1379                                 EXT4_ERROR_INODE(inode,
1380                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1381                                                  *logical);
1382                                 return -EIO;
1383                         }
1384                 }
1385                 goto found_extent;
1386         }
1387
1388         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1389                 EXT4_ERROR_INODE(inode,
1390                                  "logical %d < ee_block %d + ee_len %d!",
1391                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1392                 return -EIO;
1393         }
1394
1395         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1396                 /* next allocated block in this leaf */
1397                 ex++;
1398                 goto found_extent;
1399         }
1400
1401         /* go up and search for index to the right */
1402         while (--depth >= 0) {
1403                 ix = path[depth].p_idx;
1404                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1405                         goto got_index;
1406         }
1407
1408         /* we've gone up to the root and found no index to the right */
1409         return 0;
1410
1411 got_index:
1412         /* we've found index to the right, let's
1413          * follow it and find the closest allocated
1414          * block to the right */
1415         ix++;
1416         block = ext4_idx_pblock(ix);
1417         while (++depth < path->p_depth) {
1418                 bh = sb_bread(inode->i_sb, block);
1419                 if (bh == NULL)
1420                         return -EIO;
1421                 eh = ext_block_hdr(bh);
1422                 /* subtract from p_depth to get proper eh_depth */
1423                 if (ext4_ext_check_block(inode, eh,
1424                                          path->p_depth - depth, bh)) {
1425                         put_bh(bh);
1426                         return -EIO;
1427                 }
1428                 ix = EXT_FIRST_INDEX(eh);
1429                 block = ext4_idx_pblock(ix);
1430                 put_bh(bh);
1431         }
1432
1433         bh = sb_bread(inode->i_sb, block);
1434         if (bh == NULL)
1435                 return -EIO;
1436         eh = ext_block_hdr(bh);
1437         if (ext4_ext_check_block(inode, eh, path->p_depth - depth, bh)) {
1438                 put_bh(bh);
1439                 return -EIO;
1440         }
1441         ex = EXT_FIRST_EXTENT(eh);
1442 found_extent:
1443         *logical = le32_to_cpu(ex->ee_block);
1444         *phys = ext4_ext_pblock(ex);
1445         *ret_ex = ex;
1446         if (bh)
1447                 put_bh(bh);
1448         return 0;
1449 }
1450
1451 /*
1452  * ext4_ext_next_allocated_block:
1453  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1454  * NOTE: it considers block number from index entry as
1455  * allocated block. Thus, index entries have to be consistent
1456  * with leaves.
1457  */
1458 static ext4_lblk_t
1459 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1460 {
1461         int depth;
1462
1463         BUG_ON(path == NULL);
1464         depth = path->p_depth;
1465
1466         if (depth == 0 && path->p_ext == NULL)
1467                 return EXT_MAX_BLOCKS;
1468
1469         while (depth >= 0) {
1470                 if (depth == path->p_depth) {
1471                         /* leaf */
1472                         if (path[depth].p_ext &&
1473                                 path[depth].p_ext !=
1474                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1475                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1476                 } else {
1477                         /* index */
1478                         if (path[depth].p_idx !=
1479                                         EXT_LAST_INDEX(path[depth].p_hdr))
1480                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1481                 }
1482                 depth--;
1483         }
1484
1485         return EXT_MAX_BLOCKS;
1486 }
1487
1488 /*
1489  * ext4_ext_next_leaf_block:
1490  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1491  */
1492 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1493 {
1494         int depth;
1495
1496         BUG_ON(path == NULL);
1497         depth = path->p_depth;
1498
1499         /* zero-tree has no leaf blocks at all */
1500         if (depth == 0)
1501                 return EXT_MAX_BLOCKS;
1502
1503         /* go to index block */
1504         depth--;
1505
1506         while (depth >= 0) {
1507                 if (path[depth].p_idx !=
1508                                 EXT_LAST_INDEX(path[depth].p_hdr))
1509                         return (ext4_lblk_t)
1510                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1511                 depth--;
1512         }
1513
1514         return EXT_MAX_BLOCKS;
1515 }
1516
1517 /*
1518  * ext4_ext_correct_indexes:
1519  * if leaf gets modified and modified extent is first in the leaf,
1520  * then we have to correct all indexes above.
1521  * TODO: do we need to correct tree in all cases?
1522  */
1523 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1524                                 struct ext4_ext_path *path)
1525 {
1526         struct ext4_extent_header *eh;
1527         int depth = ext_depth(inode);
1528         struct ext4_extent *ex;
1529         __le32 border;
1530         int k, err = 0;
1531
1532         eh = path[depth].p_hdr;
1533         ex = path[depth].p_ext;
1534
1535         if (unlikely(ex == NULL || eh == NULL)) {
1536                 EXT4_ERROR_INODE(inode,
1537                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1538                 return -EIO;
1539         }
1540
1541         if (depth == 0) {
1542                 /* there is no tree at all */
1543                 return 0;
1544         }
1545
1546         if (ex != EXT_FIRST_EXTENT(eh)) {
1547                 /* we correct tree if first leaf got modified only */
1548                 return 0;
1549         }
1550
1551         /*
1552          * TODO: we need correction if border is smaller than current one
1553          */
1554         k = depth - 1;
1555         border = path[depth].p_ext->ee_block;
1556         err = ext4_ext_get_access(handle, inode, path + k);
1557         if (err)
1558                 return err;
1559         path[k].p_idx->ei_block = border;
1560         err = ext4_ext_dirty(handle, inode, path + k);
1561         if (err)
1562                 return err;
1563
1564         while (k--) {
1565                 /* change all left-side indexes */
1566                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1567                         break;
1568                 err = ext4_ext_get_access(handle, inode, path + k);
1569                 if (err)
1570                         break;
1571                 path[k].p_idx->ei_block = border;
1572                 err = ext4_ext_dirty(handle, inode, path + k);
1573                 if (err)
1574                         break;
1575         }
1576
1577         return err;
1578 }
1579
1580 int
1581 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1582                                 struct ext4_extent *ex2)
1583 {
1584         unsigned short ext1_ee_len, ext2_ee_len, max_len;
1585
1586         /*
1587          * Make sure that either both extents are uninitialized, or
1588          * both are _not_.
1589          */
1590         if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1591                 return 0;
1592
1593         if (ext4_ext_is_uninitialized(ex1))
1594                 max_len = EXT_UNINIT_MAX_LEN;
1595         else
1596                 max_len = EXT_INIT_MAX_LEN;
1597
1598         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1599         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1600
1601         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1602                         le32_to_cpu(ex2->ee_block))
1603                 return 0;
1604
1605         /*
1606          * To allow future support for preallocated extents to be added
1607          * as an RO_COMPAT feature, refuse to merge to extents if
1608          * this can result in the top bit of ee_len being set.
1609          */
1610         if (ext1_ee_len + ext2_ee_len > max_len)
1611                 return 0;
1612 #ifdef AGGRESSIVE_TEST
1613         if (ext1_ee_len >= 4)
1614                 return 0;
1615 #endif
1616
1617         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1618                 return 1;
1619         return 0;
1620 }
1621
1622 /*
1623  * This function tries to merge the "ex" extent to the next extent in the tree.
1624  * It always tries to merge towards right. If you want to merge towards
1625  * left, pass "ex - 1" as argument instead of "ex".
1626  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1627  * 1 if they got merged.
1628  */
1629 static int ext4_ext_try_to_merge_right(struct inode *inode,
1630                                  struct ext4_ext_path *path,
1631                                  struct ext4_extent *ex)
1632 {
1633         struct ext4_extent_header *eh;
1634         unsigned int depth, len;
1635         int merge_done = 0;
1636         int uninitialized = 0;
1637
1638         depth = ext_depth(inode);
1639         BUG_ON(path[depth].p_hdr == NULL);
1640         eh = path[depth].p_hdr;
1641
1642         while (ex < EXT_LAST_EXTENT(eh)) {
1643                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1644                         break;
1645                 /* merge with next extent! */
1646                 if (ext4_ext_is_uninitialized(ex))
1647                         uninitialized = 1;
1648                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1649                                 + ext4_ext_get_actual_len(ex + 1));
1650                 if (uninitialized)
1651                         ext4_ext_mark_uninitialized(ex);
1652
1653                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1654                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1655                                 * sizeof(struct ext4_extent);
1656                         memmove(ex + 1, ex + 2, len);
1657                 }
1658                 le16_add_cpu(&eh->eh_entries, -1);
1659                 merge_done = 1;
1660                 WARN_ON(eh->eh_entries == 0);
1661                 if (!eh->eh_entries)
1662                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1663         }
1664
1665         return merge_done;
1666 }
1667
1668 /*
1669  * This function does a very simple check to see if we can collapse
1670  * an extent tree with a single extent tree leaf block into the inode.
1671  */
1672 static void ext4_ext_try_to_merge_up(handle_t *handle,
1673                                      struct inode *inode,
1674                                      struct ext4_ext_path *path)
1675 {
1676         size_t s;
1677         unsigned max_root = ext4_ext_space_root(inode, 0);
1678         ext4_fsblk_t blk;
1679
1680         if ((path[0].p_depth != 1) ||
1681             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1682             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1683                 return;
1684
1685         /*
1686          * We need to modify the block allocation bitmap and the block
1687          * group descriptor to release the extent tree block.  If we
1688          * can't get the journal credits, give up.
1689          */
1690         if (ext4_journal_extend(handle, 2))
1691                 return;
1692
1693         /*
1694          * Copy the extent data up to the inode
1695          */
1696         blk = ext4_idx_pblock(path[0].p_idx);
1697         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1698                 sizeof(struct ext4_extent_idx);
1699         s += sizeof(struct ext4_extent_header);
1700
1701         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1702         path[0].p_depth = 0;
1703         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1704                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1705         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1706
1707         brelse(path[1].p_bh);
1708         ext4_free_blocks(handle, inode, NULL, blk, 1,
1709                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1710 }
1711
1712 /*
1713  * This function tries to merge the @ex extent to neighbours in the tree.
1714  * return 1 if merge left else 0.
1715  */
1716 static void ext4_ext_try_to_merge(handle_t *handle,
1717                                   struct inode *inode,
1718                                   struct ext4_ext_path *path,
1719                                   struct ext4_extent *ex) {
1720         struct ext4_extent_header *eh;
1721         unsigned int depth;
1722         int merge_done = 0;
1723
1724         depth = ext_depth(inode);
1725         BUG_ON(path[depth].p_hdr == NULL);
1726         eh = path[depth].p_hdr;
1727
1728         if (ex > EXT_FIRST_EXTENT(eh))
1729                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1730
1731         if (!merge_done)
1732                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1733
1734         ext4_ext_try_to_merge_up(handle, inode, path);
1735 }
1736
1737 /*
1738  * check if a portion of the "newext" extent overlaps with an
1739  * existing extent.
1740  *
1741  * If there is an overlap discovered, it updates the length of the newext
1742  * such that there will be no overlap, and then returns 1.
1743  * If there is no overlap found, it returns 0.
1744  */
1745 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1746                                            struct inode *inode,
1747                                            struct ext4_extent *newext,
1748                                            struct ext4_ext_path *path)
1749 {
1750         ext4_lblk_t b1, b2;
1751         unsigned int depth, len1;
1752         unsigned int ret = 0;
1753
1754         b1 = le32_to_cpu(newext->ee_block);
1755         len1 = ext4_ext_get_actual_len(newext);
1756         depth = ext_depth(inode);
1757         if (!path[depth].p_ext)
1758                 goto out;
1759         b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1760         b2 &= ~(sbi->s_cluster_ratio - 1);
1761
1762         /*
1763          * get the next allocated block if the extent in the path
1764          * is before the requested block(s)
1765          */
1766         if (b2 < b1) {
1767                 b2 = ext4_ext_next_allocated_block(path);
1768                 if (b2 == EXT_MAX_BLOCKS)
1769                         goto out;
1770                 b2 &= ~(sbi->s_cluster_ratio - 1);
1771         }
1772
1773         /* check for wrap through zero on extent logical start block*/
1774         if (b1 + len1 < b1) {
1775                 len1 = EXT_MAX_BLOCKS - b1;
1776                 newext->ee_len = cpu_to_le16(len1);
1777                 ret = 1;
1778         }
1779
1780         /* check for overlap */
1781         if (b1 + len1 > b2) {
1782                 newext->ee_len = cpu_to_le16(b2 - b1);
1783                 ret = 1;
1784         }
1785 out:
1786         return ret;
1787 }
1788
1789 /*
1790  * ext4_ext_insert_extent:
1791  * tries to merge requsted extent into the existing extent or
1792  * inserts requested extent as new one into the tree,
1793  * creating new leaf in the no-space case.
1794  */
1795 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1796                                 struct ext4_ext_path *path,
1797                                 struct ext4_extent *newext, int flag)
1798 {
1799         struct ext4_extent_header *eh;
1800         struct ext4_extent *ex, *fex;
1801         struct ext4_extent *nearex; /* nearest extent */
1802         struct ext4_ext_path *npath = NULL;
1803         int depth, len, err;
1804         ext4_lblk_t next;
1805         unsigned uninitialized = 0;
1806         int flags = 0;
1807
1808         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1809                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1810                 return -EIO;
1811         }
1812         depth = ext_depth(inode);
1813         ex = path[depth].p_ext;
1814         if (unlikely(path[depth].p_hdr == NULL)) {
1815                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1816                 return -EIO;
1817         }
1818
1819         /* try to insert block into found extent and return */
1820         if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)
1821                 && ext4_can_extents_be_merged(inode, ex, newext)) {
1822                 ext_debug("append [%d]%d block to %u:[%d]%d (from %llu)\n",
1823                           ext4_ext_is_uninitialized(newext),
1824                           ext4_ext_get_actual_len(newext),
1825                           le32_to_cpu(ex->ee_block),
1826                           ext4_ext_is_uninitialized(ex),
1827                           ext4_ext_get_actual_len(ex),
1828                           ext4_ext_pblock(ex));
1829                 err = ext4_ext_get_access(handle, inode, path + depth);
1830                 if (err)
1831                         return err;
1832
1833                 /*
1834                  * ext4_can_extents_be_merged should have checked that either
1835                  * both extents are uninitialized, or both aren't. Thus we
1836                  * need to check only one of them here.
1837                  */
1838                 if (ext4_ext_is_uninitialized(ex))
1839                         uninitialized = 1;
1840                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1841                                         + ext4_ext_get_actual_len(newext));
1842                 if (uninitialized)
1843                         ext4_ext_mark_uninitialized(ex);
1844                 eh = path[depth].p_hdr;
1845                 nearex = ex;
1846                 goto merge;
1847         }
1848
1849         depth = ext_depth(inode);
1850         eh = path[depth].p_hdr;
1851         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1852                 goto has_space;
1853
1854         /* probably next leaf has space for us? */
1855         fex = EXT_LAST_EXTENT(eh);
1856         next = EXT_MAX_BLOCKS;
1857         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
1858                 next = ext4_ext_next_leaf_block(path);
1859         if (next != EXT_MAX_BLOCKS) {
1860                 ext_debug("next leaf block - %u\n", next);
1861                 BUG_ON(npath != NULL);
1862                 npath = ext4_ext_find_extent(inode, next, NULL);
1863                 if (IS_ERR(npath))
1864                         return PTR_ERR(npath);
1865                 BUG_ON(npath->p_depth != path->p_depth);
1866                 eh = npath[depth].p_hdr;
1867                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1868                         ext_debug("next leaf isn't full(%d)\n",
1869                                   le16_to_cpu(eh->eh_entries));
1870                         path = npath;
1871                         goto has_space;
1872                 }
1873                 ext_debug("next leaf has no free space(%d,%d)\n",
1874                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1875         }
1876
1877         /*
1878          * There is no free space in the found leaf.
1879          * We're gonna add a new leaf in the tree.
1880          */
1881         if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT)
1882                 flags = EXT4_MB_USE_ROOT_BLOCKS;
1883         err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
1884         if (err)
1885                 goto cleanup;
1886         depth = ext_depth(inode);
1887         eh = path[depth].p_hdr;
1888
1889 has_space:
1890         nearex = path[depth].p_ext;
1891
1892         err = ext4_ext_get_access(handle, inode, path + depth);
1893         if (err)
1894                 goto cleanup;
1895
1896         if (!nearex) {
1897                 /* there is no extent in this leaf, create first one */
1898                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
1899                                 le32_to_cpu(newext->ee_block),
1900                                 ext4_ext_pblock(newext),
1901                                 ext4_ext_is_uninitialized(newext),
1902                                 ext4_ext_get_actual_len(newext));
1903                 nearex = EXT_FIRST_EXTENT(eh);
1904         } else {
1905                 if (le32_to_cpu(newext->ee_block)
1906                            > le32_to_cpu(nearex->ee_block)) {
1907                         /* Insert after */
1908                         ext_debug("insert %u:%llu:[%d]%d before: "
1909                                         "nearest %p\n",
1910                                         le32_to_cpu(newext->ee_block),
1911                                         ext4_ext_pblock(newext),
1912                                         ext4_ext_is_uninitialized(newext),
1913                                         ext4_ext_get_actual_len(newext),
1914                                         nearex);
1915                         nearex++;
1916                 } else {
1917                         /* Insert before */
1918                         BUG_ON(newext->ee_block == nearex->ee_block);
1919                         ext_debug("insert %u:%llu:[%d]%d after: "
1920                                         "nearest %p\n",
1921                                         le32_to_cpu(newext->ee_block),
1922                                         ext4_ext_pblock(newext),
1923                                         ext4_ext_is_uninitialized(newext),
1924                                         ext4_ext_get_actual_len(newext),
1925                                         nearex);
1926                 }
1927                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
1928                 if (len > 0) {
1929                         ext_debug("insert %u:%llu:[%d]%d: "
1930                                         "move %d extents from 0x%p to 0x%p\n",
1931                                         le32_to_cpu(newext->ee_block),
1932                                         ext4_ext_pblock(newext),
1933                                         ext4_ext_is_uninitialized(newext),
1934                                         ext4_ext_get_actual_len(newext),
1935                                         len, nearex, nearex + 1);
1936                         memmove(nearex + 1, nearex,
1937                                 len * sizeof(struct ext4_extent));
1938                 }
1939         }
1940
1941         le16_add_cpu(&eh->eh_entries, 1);
1942         path[depth].p_ext = nearex;
1943         nearex->ee_block = newext->ee_block;
1944         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
1945         nearex->ee_len = newext->ee_len;
1946
1947 merge:
1948         /* try to merge extents */
1949         if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
1950                 ext4_ext_try_to_merge(handle, inode, path, nearex);
1951
1952
1953         /* time to correct all indexes above */
1954         err = ext4_ext_correct_indexes(handle, inode, path);
1955         if (err)
1956                 goto cleanup;
1957
1958         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
1959
1960 cleanup:
1961         if (npath) {
1962                 ext4_ext_drop_refs(npath);
1963                 kfree(npath);
1964         }
1965         return err;
1966 }
1967
1968 static int ext4_fill_fiemap_extents(struct inode *inode,
1969                                     ext4_lblk_t block, ext4_lblk_t num,
1970                                     struct fiemap_extent_info *fieinfo)
1971 {
1972         struct ext4_ext_path *path = NULL;
1973         struct ext4_extent *ex;
1974         struct extent_status es;
1975         ext4_lblk_t next, next_del, start = 0, end = 0;
1976         ext4_lblk_t last = block + num;
1977         int exists, depth = 0, err = 0;
1978         unsigned int flags = 0;
1979         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
1980
1981         while (block < last && block != EXT_MAX_BLOCKS) {
1982                 num = last - block;
1983                 /* find extent for this block */
1984                 down_read(&EXT4_I(inode)->i_data_sem);
1985
1986                 if (path && ext_depth(inode) != depth) {
1987                         /* depth was changed. we have to realloc path */
1988                         kfree(path);
1989                         path = NULL;
1990                 }
1991
1992                 path = ext4_ext_find_extent(inode, block, path);
1993                 if (IS_ERR(path)) {
1994                         up_read(&EXT4_I(inode)->i_data_sem);
1995                         err = PTR_ERR(path);
1996                         path = NULL;
1997                         break;
1998                 }
1999
2000                 depth = ext_depth(inode);
2001                 if (unlikely(path[depth].p_hdr == NULL)) {
2002                         up_read(&EXT4_I(inode)->i_data_sem);
2003                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2004                         err = -EIO;
2005                         break;
2006                 }
2007                 ex = path[depth].p_ext;
2008                 next = ext4_ext_next_allocated_block(path);
2009                 ext4_ext_drop_refs(path);
2010
2011                 flags = 0;
2012                 exists = 0;
2013                 if (!ex) {
2014                         /* there is no extent yet, so try to allocate
2015                          * all requested space */
2016                         start = block;
2017                         end = block + num;
2018                 } else if (le32_to_cpu(ex->ee_block) > block) {
2019                         /* need to allocate space before found extent */
2020                         start = block;
2021                         end = le32_to_cpu(ex->ee_block);
2022                         if (block + num < end)
2023                                 end = block + num;
2024                 } else if (block >= le32_to_cpu(ex->ee_block)
2025                                         + ext4_ext_get_actual_len(ex)) {
2026                         /* need to allocate space after found extent */
2027                         start = block;
2028                         end = block + num;
2029                         if (end >= next)
2030                                 end = next;
2031                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2032                         /*
2033                          * some part of requested space is covered
2034                          * by found extent
2035                          */
2036                         start = block;
2037                         end = le32_to_cpu(ex->ee_block)
2038                                 + ext4_ext_get_actual_len(ex);
2039                         if (block + num < end)
2040                                 end = block + num;
2041                         exists = 1;
2042                 } else {
2043                         BUG();
2044                 }
2045                 BUG_ON(end <= start);
2046
2047                 if (!exists) {
2048                         es.es_lblk = start;
2049                         es.es_len = end - start;
2050                         es.es_pblk = 0;
2051                 } else {
2052                         es.es_lblk = le32_to_cpu(ex->ee_block);
2053                         es.es_len = ext4_ext_get_actual_len(ex);
2054                         es.es_pblk = ext4_ext_pblock(ex);
2055                         if (ext4_ext_is_uninitialized(ex))
2056                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2057                 }
2058
2059                 /*
2060                  * Find delayed extent and update es accordingly. We call
2061                  * it even in !exists case to find out whether es is the
2062                  * last existing extent or not.
2063                  */
2064                 next_del = ext4_find_delayed_extent(inode, &es);
2065                 if (!exists && next_del) {
2066                         exists = 1;
2067                         flags |= FIEMAP_EXTENT_DELALLOC;
2068                 }
2069                 up_read(&EXT4_I(inode)->i_data_sem);
2070
2071                 if (unlikely(es.es_len == 0)) {
2072                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2073                         err = -EIO;
2074                         break;
2075                 }
2076
2077                 /*
2078                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2079                  * we need to check next == EXT_MAX_BLOCKS because it is
2080                  * possible that an extent is with unwritten and delayed
2081                  * status due to when an extent is delayed allocated and
2082                  * is allocated by fallocate status tree will track both of
2083                  * them in a extent.
2084                  *
2085                  * So we could return a unwritten and delayed extent, and
2086                  * its block is equal to 'next'.
2087                  */
2088                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2089                         flags |= FIEMAP_EXTENT_LAST;
2090                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2091                                      next != EXT_MAX_BLOCKS)) {
2092                                 EXT4_ERROR_INODE(inode,
2093                                                  "next extent == %u, next "
2094                                                  "delalloc extent = %u",
2095                                                  next, next_del);
2096                                 err = -EIO;
2097                                 break;
2098                         }
2099                 }
2100
2101                 if (exists) {
2102                         err = fiemap_fill_next_extent(fieinfo,
2103                                 (__u64)es.es_lblk << blksize_bits,
2104                                 (__u64)es.es_pblk << blksize_bits,
2105                                 (__u64)es.es_len << blksize_bits,
2106                                 flags);
2107                         if (err < 0)
2108                                 break;
2109                         if (err == 1) {
2110                                 err = 0;
2111                                 break;
2112                         }
2113                 }
2114
2115                 block = es.es_lblk + es.es_len;
2116         }
2117
2118         if (path) {
2119                 ext4_ext_drop_refs(path);
2120                 kfree(path);
2121         }
2122
2123         return err;
2124 }
2125
2126 /*
2127  * ext4_ext_put_gap_in_cache:
2128  * calculate boundaries of the gap that the requested block fits into
2129  * and cache this gap
2130  */
2131 static void
2132 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
2133                                 ext4_lblk_t block)
2134 {
2135         int depth = ext_depth(inode);
2136         unsigned long len;
2137         ext4_lblk_t lblock;
2138         struct ext4_extent *ex;
2139
2140         ex = path[depth].p_ext;
2141         if (ex == NULL) {
2142                 /*
2143                  * there is no extent yet, so gap is [0;-] and we
2144                  * don't cache it
2145                  */
2146                 ext_debug("cache gap(whole file):");
2147         } else if (block < le32_to_cpu(ex->ee_block)) {
2148                 lblock = block;
2149                 len = le32_to_cpu(ex->ee_block) - block;
2150                 ext_debug("cache gap(before): %u [%u:%u]",
2151                                 block,
2152                                 le32_to_cpu(ex->ee_block),
2153                                  ext4_ext_get_actual_len(ex));
2154                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2155                         ext4_es_insert_extent(inode, lblock, len, ~0,
2156                                               EXTENT_STATUS_HOLE);
2157         } else if (block >= le32_to_cpu(ex->ee_block)
2158                         + ext4_ext_get_actual_len(ex)) {
2159                 ext4_lblk_t next;
2160                 lblock = le32_to_cpu(ex->ee_block)
2161                         + ext4_ext_get_actual_len(ex);
2162
2163                 next = ext4_ext_next_allocated_block(path);
2164                 ext_debug("cache gap(after): [%u:%u] %u",
2165                                 le32_to_cpu(ex->ee_block),
2166                                 ext4_ext_get_actual_len(ex),
2167                                 block);
2168                 BUG_ON(next == lblock);
2169                 len = next - lblock;
2170                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2171                         ext4_es_insert_extent(inode, lblock, len, ~0,
2172                                               EXTENT_STATUS_HOLE);
2173         } else {
2174                 lblock = len = 0;
2175                 BUG();
2176         }
2177
2178         ext_debug(" -> %u:%lu\n", lblock, len);
2179 }
2180
2181 /*
2182  * ext4_ext_rm_idx:
2183  * removes index from the index block.
2184  */
2185 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2186                         struct ext4_ext_path *path, int depth)
2187 {
2188         int err;
2189         ext4_fsblk_t leaf;
2190
2191         /* free index block */
2192         depth--;
2193         path = path + depth;
2194         leaf = ext4_idx_pblock(path->p_idx);
2195         if (unlikely(path->p_hdr->eh_entries == 0)) {
2196                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2197                 return -EIO;
2198         }
2199         err = ext4_ext_get_access(handle, inode, path);
2200         if (err)
2201                 return err;
2202
2203         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2204                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2205                 len *= sizeof(struct ext4_extent_idx);
2206                 memmove(path->p_idx, path->p_idx + 1, len);
2207         }
2208
2209         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2210         err = ext4_ext_dirty(handle, inode, path);
2211         if (err)
2212                 return err;
2213         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2214         trace_ext4_ext_rm_idx(inode, leaf);
2215
2216         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2217                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2218
2219         while (--depth >= 0) {
2220                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2221                         break;
2222                 path--;
2223                 err = ext4_ext_get_access(handle, inode, path);
2224                 if (err)
2225                         break;
2226                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2227                 err = ext4_ext_dirty(handle, inode, path);
2228                 if (err)
2229                         break;
2230         }
2231         return err;
2232 }
2233
2234 /*
2235  * ext4_ext_calc_credits_for_single_extent:
2236  * This routine returns max. credits that needed to insert an extent
2237  * to the extent tree.
2238  * When pass the actual path, the caller should calculate credits
2239  * under i_data_sem.
2240  */
2241 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2242                                                 struct ext4_ext_path *path)
2243 {
2244         if (path) {
2245                 int depth = ext_depth(inode);
2246                 int ret = 0;
2247
2248                 /* probably there is space in leaf? */
2249                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2250                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2251
2252                         /*
2253                          *  There are some space in the leaf tree, no
2254                          *  need to account for leaf block credit
2255                          *
2256                          *  bitmaps and block group descriptor blocks
2257                          *  and other metadata blocks still need to be
2258                          *  accounted.
2259                          */
2260                         /* 1 bitmap, 1 block group descriptor */
2261                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2262                         return ret;
2263                 }
2264         }
2265
2266         return ext4_chunk_trans_blocks(inode, nrblocks);
2267 }
2268
2269 /*
2270  * How many index/leaf blocks need to change/allocate to modify nrblocks?
2271  *
2272  * if nrblocks are fit in a single extent (chunk flag is 1), then
2273  * in the worse case, each tree level index/leaf need to be changed
2274  * if the tree split due to insert a new extent, then the old tree
2275  * index/leaf need to be updated too
2276  *
2277  * If the nrblocks are discontiguous, they could cause
2278  * the whole tree split more than once, but this is really rare.
2279  */
2280 int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
2281 {
2282         int index;
2283         int depth;
2284
2285         /* If we are converting the inline data, only one is needed here. */
2286         if (ext4_has_inline_data(inode))
2287                 return 1;
2288
2289         depth = ext_depth(inode);
2290
2291         if (chunk)
2292                 index = depth * 2;
2293         else
2294                 index = depth * 3;
2295
2296         return index;
2297 }
2298
2299 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2300                               struct ext4_extent *ex,
2301                               ext4_fsblk_t *partial_cluster,
2302                               ext4_lblk_t from, ext4_lblk_t to)
2303 {
2304         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2305         unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2306         ext4_fsblk_t pblk;
2307         int flags = 0;
2308
2309         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2310                 flags |= EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2311         else if (ext4_should_journal_data(inode))
2312                 flags |= EXT4_FREE_BLOCKS_FORGET;
2313
2314         /*
2315          * For bigalloc file systems, we never free a partial cluster
2316          * at the beginning of the extent.  Instead, we make a note
2317          * that we tried freeing the cluster, and check to see if we
2318          * need to free it on a subsequent call to ext4_remove_blocks,
2319          * or at the end of the ext4_truncate() operation.
2320          */
2321         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2322
2323         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2324         /*
2325          * If we have a partial cluster, and it's different from the
2326          * cluster of the last block, we need to explicitly free the
2327          * partial cluster here.
2328          */
2329         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2330         if (*partial_cluster && (EXT4_B2C(sbi, pblk) != *partial_cluster)) {
2331                 ext4_free_blocks(handle, inode, NULL,
2332                                  EXT4_C2B(sbi, *partial_cluster),
2333                                  sbi->s_cluster_ratio, flags);
2334                 *partial_cluster = 0;
2335         }
2336
2337 #ifdef EXTENTS_STATS
2338         {
2339                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2340                 spin_lock(&sbi->s_ext_stats_lock);
2341                 sbi->s_ext_blocks += ee_len;
2342                 sbi->s_ext_extents++;
2343                 if (ee_len < sbi->s_ext_min)
2344                         sbi->s_ext_min = ee_len;
2345                 if (ee_len > sbi->s_ext_max)
2346                         sbi->s_ext_max = ee_len;
2347                 if (ext_depth(inode) > sbi->s_depth_max)
2348                         sbi->s_depth_max = ext_depth(inode);
2349                 spin_unlock(&sbi->s_ext_stats_lock);
2350         }
2351 #endif
2352         if (from >= le32_to_cpu(ex->ee_block)
2353             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2354                 /* tail removal */
2355                 ext4_lblk_t num;
2356
2357                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2358                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2359                 ext_debug("free last %u blocks starting %llu\n", num, pblk);
2360                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2361                 /*
2362                  * If the block range to be freed didn't start at the
2363                  * beginning of a cluster, and we removed the entire
2364                  * extent, save the partial cluster here, since we
2365                  * might need to delete if we determine that the
2366                  * truncate operation has removed all of the blocks in
2367                  * the cluster.
2368                  */
2369                 if (pblk & (sbi->s_cluster_ratio - 1) &&
2370                     (ee_len == num))
2371                         *partial_cluster = EXT4_B2C(sbi, pblk);
2372                 else
2373                         *partial_cluster = 0;
2374         } else if (from == le32_to_cpu(ex->ee_block)
2375                    && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
2376                 /* head removal */
2377                 ext4_lblk_t num;
2378                 ext4_fsblk_t start;
2379
2380                 num = to - from;
2381                 start = ext4_ext_pblock(ex);
2382
2383                 ext_debug("free first %u blocks starting %llu\n", num, start);
2384                 ext4_free_blocks(handle, inode, NULL, start, num, flags);
2385
2386         } else {
2387                 printk(KERN_INFO "strange request: removal(2) "
2388                                 "%u-%u from %u:%u\n",
2389                                 from, to, le32_to_cpu(ex->ee_block), ee_len);
2390         }
2391         return 0;
2392 }
2393
2394
2395 /*
2396  * ext4_ext_rm_leaf() Removes the extents associated with the
2397  * blocks appearing between "start" and "end", and splits the extents
2398  * if "start" and "end" appear in the same extent
2399  *
2400  * @handle: The journal handle
2401  * @inode:  The files inode
2402  * @path:   The path to the leaf
2403  * @start:  The first block to remove
2404  * @end:   The last block to remove
2405  */
2406 static int
2407 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2408                  struct ext4_ext_path *path, ext4_fsblk_t *partial_cluster,
2409                  ext4_lblk_t start, ext4_lblk_t end)
2410 {
2411         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2412         int err = 0, correct_index = 0;
2413         int depth = ext_depth(inode), credits;
2414         struct ext4_extent_header *eh;
2415         ext4_lblk_t a, b;
2416         unsigned num;
2417         ext4_lblk_t ex_ee_block;
2418         unsigned short ex_ee_len;
2419         unsigned uninitialized = 0;
2420         struct ext4_extent *ex;
2421
2422         /* the header must be checked already in ext4_ext_remove_space() */
2423         ext_debug("truncate since %u in leaf to %u\n", start, end);
2424         if (!path[depth].p_hdr)
2425                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2426         eh = path[depth].p_hdr;
2427         if (unlikely(path[depth].p_hdr == NULL)) {
2428                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2429                 return -EIO;
2430         }
2431         /* find where to start removing */
2432         ex = EXT_LAST_EXTENT(eh);
2433
2434         ex_ee_block = le32_to_cpu(ex->ee_block);
2435         ex_ee_len = ext4_ext_get_actual_len(ex);
2436
2437         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2438
2439         while (ex >= EXT_FIRST_EXTENT(eh) &&
2440                         ex_ee_block + ex_ee_len > start) {
2441
2442                 if (ext4_ext_is_uninitialized(ex))
2443                         uninitialized = 1;
2444                 else
2445                         uninitialized = 0;
2446
2447                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2448                          uninitialized, ex_ee_len);
2449                 path[depth].p_ext = ex;
2450
2451                 a = ex_ee_block > start ? ex_ee_block : start;
2452                 b = ex_ee_block+ex_ee_len - 1 < end ?
2453                         ex_ee_block+ex_ee_len - 1 : end;
2454
2455                 ext_debug("  border %u:%u\n", a, b);
2456
2457                 /* If this extent is beyond the end of the hole, skip it */
2458                 if (end < ex_ee_block) {
2459                         ex--;
2460                         ex_ee_block = le32_to_cpu(ex->ee_block);
2461                         ex_ee_len = ext4_ext_get_actual_len(ex);
2462                         continue;
2463                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2464                         EXT4_ERROR_INODE(inode,
2465                                          "can not handle truncate %u:%u "
2466                                          "on extent %u:%u",
2467                                          start, end, ex_ee_block,
2468                                          ex_ee_block + ex_ee_len - 1);
2469                         err = -EIO;
2470                         goto out;
2471                 } else if (a != ex_ee_block) {
2472                         /* remove tail of the extent */
2473                         num = a - ex_ee_block;
2474                 } else {
2475                         /* remove whole extent: excellent! */
2476                         num = 0;
2477                 }
2478                 /*
2479                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2480                  * descriptor) for each block group; assume two block
2481                  * groups plus ex_ee_len/blocks_per_block_group for
2482                  * the worst case
2483                  */
2484                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2485                 if (ex == EXT_FIRST_EXTENT(eh)) {
2486                         correct_index = 1;
2487                         credits += (ext_depth(inode)) + 1;
2488                 }
2489                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2490
2491                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2492                 if (err)
2493                         goto out;
2494
2495                 err = ext4_ext_get_access(handle, inode, path + depth);
2496                 if (err)
2497                         goto out;
2498
2499                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2500                                          a, b);
2501                 if (err)
2502                         goto out;
2503
2504                 if (num == 0)
2505                         /* this extent is removed; mark slot entirely unused */
2506                         ext4_ext_store_pblock(ex, 0);
2507
2508                 ex->ee_len = cpu_to_le16(num);
2509                 /*
2510                  * Do not mark uninitialized if all the blocks in the
2511                  * extent have been removed.
2512                  */
2513                 if (uninitialized && num)
2514                         ext4_ext_mark_uninitialized(ex);
2515                 /*
2516                  * If the extent was completely released,
2517                  * we need to remove it from the leaf
2518                  */
2519                 if (num == 0) {
2520                         if (end != EXT_MAX_BLOCKS - 1) {
2521                                 /*
2522                                  * For hole punching, we need to scoot all the
2523                                  * extents up when an extent is removed so that
2524                                  * we dont have blank extents in the middle
2525                                  */
2526                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2527                                         sizeof(struct ext4_extent));
2528
2529                                 /* Now get rid of the one at the end */
2530                                 memset(EXT_LAST_EXTENT(eh), 0,
2531                                         sizeof(struct ext4_extent));
2532                         }
2533                         le16_add_cpu(&eh->eh_entries, -1);
2534                 } else
2535                         *partial_cluster = 0;
2536
2537                 err = ext4_ext_dirty(handle, inode, path + depth);
2538                 if (err)
2539                         goto out;
2540
2541                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2542                                 ext4_ext_pblock(ex));
2543                 ex--;
2544                 ex_ee_block = le32_to_cpu(ex->ee_block);
2545                 ex_ee_len = ext4_ext_get_actual_len(ex);
2546         }
2547
2548         if (correct_index && eh->eh_entries)
2549                 err = ext4_ext_correct_indexes(handle, inode, path);
2550
2551         /*
2552          * If there is still a entry in the leaf node, check to see if
2553          * it references the partial cluster.  This is the only place
2554          * where it could; if it doesn't, we can free the cluster.
2555          */
2556         if (*partial_cluster && ex >= EXT_FIRST_EXTENT(eh) &&
2557             (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) !=
2558              *partial_cluster)) {
2559                 int flags = EXT4_FREE_BLOCKS_FORGET;
2560
2561                 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2562                         flags |= EXT4_FREE_BLOCKS_METADATA;
2563
2564                 ext4_free_blocks(handle, inode, NULL,
2565                                  EXT4_C2B(sbi, *partial_cluster),
2566                                  sbi->s_cluster_ratio, flags);
2567                 *partial_cluster = 0;
2568         }
2569
2570         /* if this leaf is free, then we should
2571          * remove it from index block above */
2572         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2573                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2574
2575 out:
2576         return err;
2577 }
2578
2579 /*
2580  * ext4_ext_more_to_rm:
2581  * returns 1 if current index has to be freed (even partial)
2582  */
2583 static int
2584 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2585 {
2586         BUG_ON(path->p_idx == NULL);
2587
2588         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2589                 return 0;
2590
2591         /*
2592          * if truncate on deeper level happened, it wasn't partial,
2593          * so we have to consider current index for truncation
2594          */
2595         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2596                 return 0;
2597         return 1;
2598 }
2599
2600 static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2601                                  ext4_lblk_t end)
2602 {
2603         struct super_block *sb = inode->i_sb;
2604         int depth = ext_depth(inode);
2605         struct ext4_ext_path *path = NULL;
2606         ext4_fsblk_t partial_cluster = 0;
2607         handle_t *handle;
2608         int i = 0, err = 0;
2609
2610         ext_debug("truncate since %u to %u\n", start, end);
2611
2612         /* probably first extent we're gonna free will be last in block */
2613         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2614         if (IS_ERR(handle))
2615                 return PTR_ERR(handle);
2616
2617 again:
2618         trace_ext4_ext_remove_space(inode, start, depth);
2619
2620         /*
2621          * Check if we are removing extents inside the extent tree. If that
2622          * is the case, we are going to punch a hole inside the extent tree
2623          * so we have to check whether we need to split the extent covering
2624          * the last block to remove so we can easily remove the part of it
2625          * in ext4_ext_rm_leaf().
2626          */
2627         if (end < EXT_MAX_BLOCKS - 1) {
2628                 struct ext4_extent *ex;
2629                 ext4_lblk_t ee_block;
2630
2631                 /* find extent for this block */
2632                 path = ext4_ext_find_extent(inode, end, NULL);
2633                 if (IS_ERR(path)) {
2634                         ext4_journal_stop(handle);
2635                         return PTR_ERR(path);
2636                 }
2637                 depth = ext_depth(inode);
2638                 /* Leaf not may not exist only if inode has no blocks at all */
2639                 ex = path[depth].p_ext;
2640                 if (!ex) {
2641                         if (depth) {
2642                                 EXT4_ERROR_INODE(inode,
2643                                                  "path[%d].p_hdr == NULL",
2644                                                  depth);
2645                                 err = -EIO;
2646                         }
2647                         goto out;
2648                 }
2649
2650                 ee_block = le32_to_cpu(ex->ee_block);
2651
2652                 /*
2653                  * See if the last block is inside the extent, if so split
2654                  * the extent at 'end' block so we can easily remove the
2655                  * tail of the first part of the split extent in
2656                  * ext4_ext_rm_leaf().
2657                  */
2658                 if (end >= ee_block &&
2659                     end < ee_block + ext4_ext_get_actual_len(ex) - 1) {
2660                         int split_flag = 0;
2661
2662                         if (ext4_ext_is_uninitialized(ex))
2663                                 split_flag = EXT4_EXT_MARK_UNINIT1 |
2664                                              EXT4_EXT_MARK_UNINIT2;
2665
2666                         /*
2667                          * Split the extent in two so that 'end' is the last
2668                          * block in the first new extent
2669                          */
2670                         err = ext4_split_extent_at(handle, inode, path,
2671                                                 end + 1, split_flag,
2672                                                 EXT4_GET_BLOCKS_PRE_IO |
2673                                                 EXT4_GET_BLOCKS_PUNCH_OUT_EXT);
2674
2675                         if (err < 0)
2676                                 goto out;
2677                 }
2678         }
2679         /*
2680          * We start scanning from right side, freeing all the blocks
2681          * after i_size and walking into the tree depth-wise.
2682          */
2683         depth = ext_depth(inode);
2684         if (path) {
2685                 int k = i = depth;
2686                 while (--k > 0)
2687                         path[k].p_block =
2688                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2689         } else {
2690                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2691                                GFP_NOFS);
2692                 if (path == NULL) {
2693                         ext4_journal_stop(handle);
2694                         return -ENOMEM;
2695                 }
2696                 path[0].p_depth = depth;
2697                 path[0].p_hdr = ext_inode_hdr(inode);
2698                 i = 0;
2699
2700                 if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
2701                         err = -EIO;
2702                         goto out;
2703                 }
2704         }
2705         err = 0;
2706
2707         while (i >= 0 && err == 0) {
2708                 if (i == depth) {
2709                         /* this is leaf block */
2710                         err = ext4_ext_rm_leaf(handle, inode, path,
2711                                                &partial_cluster, start,
2712                                                end);
2713                         /* root level has p_bh == NULL, brelse() eats this */
2714                         brelse(path[i].p_bh);
2715                         path[i].p_bh = NULL;
2716                         i--;
2717                         continue;
2718                 }
2719
2720                 /* this is index block */
2721                 if (!path[i].p_hdr) {
2722                         ext_debug("initialize header\n");
2723                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2724                 }
2725
2726                 if (!path[i].p_idx) {
2727                         /* this level hasn't been touched yet */
2728                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2729                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2730                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2731                                   path[i].p_hdr,
2732                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2733                 } else {
2734                         /* we were already here, see at next index */
2735                         path[i].p_idx--;
2736                 }
2737
2738                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2739                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2740                                 path[i].p_idx);
2741                 if (ext4_ext_more_to_rm(path + i)) {
2742                         struct buffer_head *bh;
2743                         /* go to the next level */
2744                         ext_debug("move to level %d (block %llu)\n",
2745                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2746                         memset(path + i + 1, 0, sizeof(*path));
2747                         bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));
2748                         if (!bh) {
2749                                 /* should we reset i_size? */
2750                                 err = -EIO;
2751                                 break;
2752                         }
2753                         if (WARN_ON(i + 1 > depth)) {
2754                                 err = -EIO;
2755                                 break;
2756                         }
2757                         if (ext4_ext_check_block(inode, ext_block_hdr(bh),
2758                                                         depth - i - 1, bh)) {
2759                                 err = -EIO;
2760                                 break;
2761                         }
2762                         path[i + 1].p_bh = bh;
2763
2764                         /* save actual number of indexes since this
2765                          * number is changed at the next iteration */
2766                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2767                         i++;
2768                 } else {
2769                         /* we finished processing this index, go up */
2770                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2771                                 /* index is empty, remove it;
2772                                  * handle must be already prepared by the
2773                                  * truncatei_leaf() */
2774                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2775                         }
2776                         /* root level has p_bh == NULL, brelse() eats this */
2777                         brelse(path[i].p_bh);
2778                         path[i].p_bh = NULL;
2779                         i--;
2780                         ext_debug("return to level %d\n", i);
2781                 }
2782         }
2783
2784         trace_ext4_ext_remove_space_done(inode, start, depth, partial_cluster,
2785                         path->p_hdr->eh_entries);
2786
2787         /* If we still have something in the partial cluster and we have removed
2788          * even the first extent, then we should free the blocks in the partial
2789          * cluster as well. */
2790         if (partial_cluster && path->p_hdr->eh_entries == 0) {
2791                 int flags = EXT4_FREE_BLOCKS_FORGET;
2792
2793                 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2794                         flags |= EXT4_FREE_BLOCKS_METADATA;
2795
2796                 ext4_free_blocks(handle, inode, NULL,
2797                                  EXT4_C2B(EXT4_SB(sb), partial_cluster),
2798                                  EXT4_SB(sb)->s_cluster_ratio, flags);
2799                 partial_cluster = 0;
2800         }
2801
2802         /* TODO: flexible tree reduction should be here */
2803         if (path->p_hdr->eh_entries == 0) {
2804                 /*
2805                  * truncate to zero freed all the tree,
2806                  * so we need to correct eh_depth
2807                  */
2808                 err = ext4_ext_get_access(handle, inode, path);
2809                 if (err == 0) {
2810                         ext_inode_hdr(inode)->eh_depth = 0;
2811                         ext_inode_hdr(inode)->eh_max =
2812                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
2813                         err = ext4_ext_dirty(handle, inode, path);
2814                 }
2815         }
2816 out:
2817         ext4_ext_drop_refs(path);
2818         kfree(path);
2819         if (err == -EAGAIN) {
2820                 path = NULL;
2821                 goto again;
2822         }
2823         ext4_journal_stop(handle);
2824
2825         return err;
2826 }
2827
2828 /*
2829  * called at mount time
2830  */
2831 void ext4_ext_init(struct super_block *sb)
2832 {
2833         /*
2834          * possible initialization would be here
2835          */
2836
2837         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2838 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
2839                 printk(KERN_INFO "EXT4-fs: file extents enabled"
2840 #ifdef AGGRESSIVE_TEST
2841                        ", aggressive tests"
2842 #endif
2843 #ifdef CHECK_BINSEARCH
2844                        ", check binsearch"
2845 #endif
2846 #ifdef EXTENTS_STATS
2847                        ", stats"
2848 #endif
2849                        "\n");
2850 #endif
2851 #ifdef EXTENTS_STATS
2852                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2853                 EXT4_SB(sb)->s_ext_min = 1 << 30;
2854                 EXT4_SB(sb)->s_ext_max = 0;
2855 #endif
2856         }
2857 }
2858
2859 /*
2860  * called at umount time
2861  */
2862 void ext4_ext_release(struct super_block *sb)
2863 {
2864         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
2865                 return;
2866
2867 #ifdef EXTENTS_STATS
2868         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2869                 struct ext4_sb_info *sbi = EXT4_SB(sb);
2870                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2871                         sbi->s_ext_blocks, sbi->s_ext_extents,
2872                         sbi->s_ext_blocks / sbi->s_ext_extents);
2873                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2874                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2875         }
2876 #endif
2877 }
2878
2879 /* FIXME!! we need to try to merge to left or right after zero-out  */
2880 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
2881 {
2882         ext4_fsblk_t ee_pblock;
2883         unsigned int ee_len;
2884         int ret;
2885
2886         ee_len    = ext4_ext_get_actual_len(ex);
2887         ee_pblock = ext4_ext_pblock(ex);
2888
2889         ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
2890         if (ret > 0)
2891                 ret = 0;
2892
2893         return ret;
2894 }
2895
2896 /*
2897  * ext4_split_extent_at() splits an extent at given block.
2898  *
2899  * @handle: the journal handle
2900  * @inode: the file inode
2901  * @path: the path to the extent
2902  * @split: the logical block where the extent is splitted.
2903  * @split_flags: indicates if the extent could be zeroout if split fails, and
2904  *               the states(init or uninit) of new extents.
2905  * @flags: flags used to insert new extent to extent tree.
2906  *
2907  *
2908  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
2909  * of which are deterimined by split_flag.
2910  *
2911  * There are two cases:
2912  *  a> the extent are splitted into two extent.
2913  *  b> split is not needed, and just mark the extent.
2914  *
2915  * return 0 on success.
2916  */
2917 static int ext4_split_extent_at(handle_t *handle,
2918                              struct inode *inode,
2919                              struct ext4_ext_path *path,
2920                              ext4_lblk_t split,
2921                              int split_flag,
2922                              int flags)
2923 {
2924         ext4_fsblk_t newblock;
2925         ext4_lblk_t ee_block;
2926         struct ext4_extent *ex, newex, orig_ex;
2927         struct ext4_extent *ex2 = NULL;
2928         unsigned int ee_len, depth;
2929         int err = 0;
2930
2931         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
2932                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
2933
2934         ext_debug("ext4_split_extents_at: inode %lu, logical"
2935                 "block %llu\n", inode->i_ino, (unsigned long long)split);
2936
2937         ext4_ext_show_leaf(inode, path);
2938
2939         depth = ext_depth(inode);
2940         ex = path[depth].p_ext;
2941         ee_block = le32_to_cpu(ex->ee_block);
2942         ee_len = ext4_ext_get_actual_len(ex);
2943         newblock = split - ee_block + ext4_ext_pblock(ex);
2944
2945         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
2946
2947         err = ext4_ext_get_access(handle, inode, path + depth);
2948         if (err)
2949                 goto out;
2950
2951         if (split == ee_block) {
2952                 /*
2953                  * case b: block @split is the block that the extent begins with
2954                  * then we just change the state of the extent, and splitting
2955                  * is not needed.
2956                  */
2957                 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2958                         ext4_ext_mark_uninitialized(ex);
2959                 else
2960                         ext4_ext_mark_initialized(ex);
2961
2962                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
2963                         ext4_ext_try_to_merge(handle, inode, path, ex);
2964
2965                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2966                 goto out;
2967         }
2968
2969         /* case a */
2970         memcpy(&orig_ex, ex, sizeof(orig_ex));
2971         ex->ee_len = cpu_to_le16(split - ee_block);
2972         if (split_flag & EXT4_EXT_MARK_UNINIT1)
2973                 ext4_ext_mark_uninitialized(ex);
2974
2975         /*
2976          * path may lead to new leaf, not to original leaf any more
2977          * after ext4_ext_insert_extent() returns,
2978          */
2979         err = ext4_ext_dirty(handle, inode, path + depth);
2980         if (err)
2981                 goto fix_extent_len;
2982
2983         ex2 = &newex;
2984         ex2->ee_block = cpu_to_le32(split);
2985         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
2986         ext4_ext_store_pblock(ex2, newblock);
2987         if (split_flag & EXT4_EXT_MARK_UNINIT2)
2988                 ext4_ext_mark_uninitialized(ex2);
2989
2990         err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
2991         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2992                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
2993                         if (split_flag & EXT4_EXT_DATA_VALID1)
2994                                 err = ext4_ext_zeroout(inode, ex2);
2995                         else
2996                                 err = ext4_ext_zeroout(inode, ex);
2997                 } else
2998                         err = ext4_ext_zeroout(inode, &orig_ex);
2999
3000                 if (err)
3001                         goto fix_extent_len;
3002                 /* update the extent length and mark as initialized */
3003                 ex->ee_len = cpu_to_le16(ee_len);
3004                 ext4_ext_try_to_merge(handle, inode, path, ex);
3005                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3006                 goto out;
3007         } else if (err)
3008                 goto fix_extent_len;
3009
3010 out:
3011         ext4_ext_show_leaf(inode, path);
3012         return err;
3013
3014 fix_extent_len:
3015         ex->ee_len = orig_ex.ee_len;
3016         ext4_ext_dirty(handle, inode, path + depth);
3017         return err;
3018 }
3019
3020 /*
3021  * ext4_split_extents() splits an extent and mark extent which is covered
3022  * by @map as split_flags indicates
3023  *
3024  * It may result in splitting the extent into multiple extents (upto three)
3025  * There are three possibilities:
3026  *   a> There is no split required
3027  *   b> Splits in two extents: Split is happening at either end of the extent
3028  *   c> Splits in three extents: Somone is splitting in middle of the extent
3029  *
3030  */
3031 static int ext4_split_extent(handle_t *handle,
3032                               struct inode *inode,
3033                               struct ext4_ext_path *path,
3034                               struct ext4_map_blocks *map,
3035                               int split_flag,
3036                               int flags)
3037 {
3038         ext4_lblk_t ee_block;
3039         struct ext4_extent *ex;
3040         unsigned int ee_len, depth;
3041         int err = 0;
3042         int uninitialized;
3043         int split_flag1, flags1;
3044
3045         depth = ext_depth(inode);
3046         ex = path[depth].p_ext;
3047         ee_block = le32_to_cpu(ex->ee_block);
3048         ee_len = ext4_ext_get_actual_len(ex);
3049         uninitialized = ext4_ext_is_uninitialized(ex);
3050
3051         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3052                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3053                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3054                 if (uninitialized)
3055                         split_flag1 |= EXT4_EXT_MARK_UNINIT1 |
3056                                        EXT4_EXT_MARK_UNINIT2;
3057                 if (split_flag & EXT4_EXT_DATA_VALID2)
3058                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3059                 err = ext4_split_extent_at(handle, inode, path,
3060                                 map->m_lblk + map->m_len, split_flag1, flags1);
3061                 if (err)
3062                         goto out;
3063         }
3064
3065         ext4_ext_drop_refs(path);
3066         path = ext4_ext_find_extent(inode, map->m_lblk, path);
3067         if (IS_ERR(path))
3068                 return PTR_ERR(path);
3069
3070         if (map->m_lblk >= ee_block) {
3071                 split_flag1 = split_flag & (EXT4_EXT_MAY_ZEROOUT |
3072                                             EXT4_EXT_DATA_VALID2);
3073                 if (uninitialized)
3074                         split_flag1 |= EXT4_EXT_MARK_UNINIT1;
3075                 if (split_flag & EXT4_EXT_MARK_UNINIT2)
3076                         split_flag1 |= EXT4_EXT_MARK_UNINIT2;
3077                 err = ext4_split_extent_at(handle, inode, path,
3078                                 map->m_lblk, split_flag1, flags);
3079                 if (err)
3080                         goto out;
3081         }
3082
3083         ext4_ext_show_leaf(inode, path);
3084 out:
3085         return err ? err : map->m_len;
3086 }
3087
3088 /*
3089  * This function is called by ext4_ext_map_blocks() if someone tries to write
3090  * to an uninitialized extent. It may result in splitting the uninitialized
3091  * extent into multiple extents (up to three - one initialized and two
3092  * uninitialized).
3093  * There are three possibilities:
3094  *   a> There is no split required: Entire extent should be initialized
3095  *   b> Splits in two extents: Write is happening at either end of the extent
3096  *   c> Splits in three extents: Somone is writing in middle of the extent
3097  *
3098  * Pre-conditions:
3099  *  - The extent pointed to by 'path' is uninitialized.
3100  *  - The extent pointed to by 'path' contains a superset
3101  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3102  *
3103  * Post-conditions on success:
3104  *  - the returned value is the number of blocks beyond map->l_lblk
3105  *    that are allocated and initialized.
3106  *    It is guaranteed to be >= map->m_len.
3107  */
3108 static int ext4_ext_convert_to_initialized(handle_t *handle,
3109                                            struct inode *inode,
3110                                            struct ext4_map_blocks *map,
3111                                            struct ext4_ext_path *path)
3112 {
3113         struct ext4_sb_info *sbi;
3114         struct ext4_extent_header *eh;
3115         struct ext4_map_blocks split_map;
3116         struct ext4_extent zero_ex;
3117         struct ext4_extent *ex;
3118         ext4_lblk_t ee_block, eof_block;
3119         unsigned int ee_len, depth;
3120         int allocated, max_zeroout = 0;
3121         int err = 0;
3122         int split_flag = 0;
3123
3124         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3125                 "block %llu, max_blocks %u\n", inode->i_ino,
3126                 (unsigned long long)map->m_lblk, map->m_len);
3127
3128         sbi = EXT4_SB(inode->i_sb);
3129         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3130                 inode->i_sb->s_blocksize_bits;
3131         if (eof_block < map->m_lblk + map->m_len)
3132                 eof_block = map->m_lblk + map->m_len;
3133
3134         depth = ext_depth(inode);
3135         eh = path[depth].p_hdr;
3136         ex = path[depth].p_ext;
3137         ee_block = le32_to_cpu(ex->ee_block);
3138         ee_len = ext4_ext_get_actual_len(ex);
3139         allocated = ee_len - (map->m_lblk - ee_block);
3140
3141         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3142
3143         /* Pre-conditions */
3144         BUG_ON(!ext4_ext_is_uninitialized(ex));
3145         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3146
3147         /*
3148          * Attempt to transfer newly initialized blocks from the currently
3149          * uninitialized extent to its left neighbor. This is much cheaper
3150          * than an insertion followed by a merge as those involve costly
3151          * memmove() calls. This is the common case in steady state for
3152          * workloads doing fallocate(FALLOC_FL_KEEP_SIZE) followed by append
3153          * writes.
3154          *
3155          * Limitations of the current logic:
3156          *  - L1: we only deal with writes at the start of the extent.
3157          *    The approach could be extended to writes at the end
3158          *    of the extent but this scenario was deemed less common.
3159          *  - L2: we do not deal with writes covering the whole extent.
3160          *    This would require removing the extent if the transfer
3161          *    is possible.
3162          *  - L3: we only attempt to merge with an extent stored in the
3163          *    same extent tree node.
3164          */
3165         if ((map->m_lblk == ee_block) &&        /*L1*/
3166                 (map->m_len < ee_len) &&        /*L2*/
3167                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L3*/
3168                 struct ext4_extent *prev_ex;
3169                 ext4_lblk_t prev_lblk;
3170                 ext4_fsblk_t prev_pblk, ee_pblk;
3171                 unsigned int prev_len, write_len;
3172
3173                 prev_ex = ex - 1;
3174                 prev_lblk = le32_to_cpu(prev_ex->ee_block);
3175                 prev_len = ext4_ext_get_actual_len(prev_ex);
3176                 prev_pblk = ext4_ext_pblock(prev_ex);
3177                 ee_pblk = ext4_ext_pblock(ex);
3178                 write_len = map->m_len;
3179
3180                 /*
3181                  * A transfer of blocks from 'ex' to 'prev_ex' is allowed
3182                  * upon those conditions:
3183                  * - C1: prev_ex is initialized,
3184                  * - C2: prev_ex is logically abutting ex,
3185                  * - C3: prev_ex is physically abutting ex,
3186                  * - C4: prev_ex can receive the additional blocks without
3187                  *   overflowing the (initialized) length limit.
3188                  */
3189                 if ((!ext4_ext_is_uninitialized(prev_ex)) &&            /*C1*/
3190                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3191                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3192                         (prev_len < (EXT_INIT_MAX_LEN - write_len))) {  /*C4*/
3193                         err = ext4_ext_get_access(handle, inode, path + depth);
3194                         if (err)
3195                                 goto out;
3196
3197                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3198                                 map, ex, prev_ex);
3199
3200                         /* Shift the start of ex by 'write_len' blocks */
3201                         ex->ee_block = cpu_to_le32(ee_block + write_len);
3202                         ext4_ext_store_pblock(ex, ee_pblk + write_len);
3203                         ex->ee_len = cpu_to_le16(ee_len - write_len);
3204                         ext4_ext_mark_uninitialized(ex); /* Restore the flag */
3205
3206                         /* Extend prev_ex by 'write_len' blocks */
3207                         prev_ex->ee_len = cpu_to_le16(prev_len + write_len);
3208
3209                         /* Mark the block containing both extents as dirty */
3210                         ext4_ext_dirty(handle, inode, path + depth);
3211
3212                         /* Update path to point to the right extent */
3213                         path[depth].p_ext = prev_ex;
3214
3215                         /* Result: number of initialized blocks past m_lblk */
3216                         allocated = write_len;
3217                         goto out;
3218                 }
3219         }
3220
3221         WARN_ON(map->m_lblk < ee_block);
3222         /*
3223          * It is safe to convert extent to initialized via explicit
3224          * zeroout only if extent is fully insde i_size or new_size.
3225          */
3226         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3227
3228         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3229                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3230                         inode->i_sb->s_blocksize_bits;
3231
3232         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3233         if (max_zeroout && (ee_len <= max_zeroout)) {
3234                 err = ext4_ext_zeroout(inode, ex);
3235                 if (err)
3236                         goto out;
3237
3238                 err = ext4_ext_get_access(handle, inode, path + depth);
3239                 if (err)
3240                         goto out;
3241                 ext4_ext_mark_initialized(ex);
3242                 ext4_ext_try_to_merge(handle, inode, path, ex);
3243                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3244                 goto out;
3245         }
3246
3247         /*
3248          * four cases:
3249          * 1. split the extent into three extents.
3250          * 2. split the extent into two extents, zeroout the first half.
3251          * 3. split the extent into two extents, zeroout the second half.
3252          * 4. split the extent into two extents with out zeroout.
3253          */
3254         split_map.m_lblk = map->m_lblk;
3255         split_map.m_len = map->m_len;
3256
3257         if (max_zeroout && (allocated > map->m_len)) {
3258                 if (allocated <= max_zeroout) {
3259                         /* case 3 */
3260                         zero_ex.ee_block =
3261                                          cpu_to_le32(map->m_lblk);
3262                         zero_ex.ee_len = cpu_to_le16(allocated);
3263                         ext4_ext_store_pblock(&zero_ex,
3264                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3265                         err = ext4_ext_zeroout(inode, &zero_ex);
3266                         if (err)
3267                                 goto out;
3268                         split_map.m_lblk = map->m_lblk;
3269                         split_map.m_len = allocated;
3270                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3271                         /* case 2 */
3272                         if (map->m_lblk != ee_block) {
3273                                 zero_ex.ee_block = ex->ee_block;
3274                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3275                                                         ee_block);
3276                                 ext4_ext_store_pblock(&zero_ex,
3277                                                       ext4_ext_pblock(ex));
3278                                 err = ext4_ext_zeroout(inode, &zero_ex);
3279                                 if (err)
3280                                         goto out;
3281                         }
3282
3283                         split_map.m_lblk = ee_block;
3284                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3285                         allocated = map->m_len;
3286                 }
3287         }
3288
3289         allocated = ext4_split_extent(handle, inode, path,
3290                                       &split_map, split_flag, 0);
3291         if (allocated < 0)
3292                 err = allocated;
3293
3294 out:
3295         return err ? err : allocated;
3296 }
3297
3298 /*
3299  * This function is called by ext4_ext_map_blocks() from
3300  * ext4_get_blocks_dio_write() when DIO to write
3301  * to an uninitialized extent.
3302  *
3303  * Writing to an uninitialized extent may result in splitting the uninitialized
3304  * extent into multiple initialized/uninitialized extents (up to three)
3305  * There are three possibilities:
3306  *   a> There is no split required: Entire extent should be uninitialized
3307  *   b> Splits in two extents: Write is happening at either end of the extent
3308  *   c> Splits in three extents: Somone is writing in middle of the extent
3309  *
3310  * One of more index blocks maybe needed if the extent tree grow after
3311  * the uninitialized extent split. To prevent ENOSPC occur at the IO
3312  * complete, we need to split the uninitialized extent before DIO submit
3313  * the IO. The uninitialized extent called at this time will be split
3314  * into three uninitialized extent(at most). After IO complete, the part
3315  * being filled will be convert to initialized by the end_io callback function
3316  * via ext4_convert_unwritten_extents().
3317  *
3318  * Returns the size of uninitialized extent to be written on success.
3319  */
3320 static int ext4_split_unwritten_extents(handle_t *handle,
3321                                         struct inode *inode,
3322                                         struct ext4_map_blocks *map,
3323                                         struct ext4_ext_path *path,
3324                                         int flags)
3325 {
3326         ext4_lblk_t eof_block;
3327         ext4_lblk_t ee_block;
3328         struct ext4_extent *ex;
3329         unsigned int ee_len;
3330         int split_flag = 0, depth;
3331
3332         ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
3333                 "block %llu, max_blocks %u\n", inode->i_ino,
3334                 (unsigned long long)map->m_lblk, map->m_len);
3335
3336         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3337                 inode->i_sb->s_blocksize_bits;
3338         if (eof_block < map->m_lblk + map->m_len)
3339                 eof_block = map->m_lblk + map->m_len;
3340         /*
3341          * It is safe to convert extent to initialized via explicit
3342          * zeroout only if extent is fully insde i_size or new_size.
3343          */
3344         depth = ext_depth(inode);
3345         ex = path[depth].p_ext;
3346         ee_block = le32_to_cpu(ex->ee_block);
3347         ee_len = ext4_ext_get_actual_len(ex);
3348
3349         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3350         split_flag |= EXT4_EXT_MARK_UNINIT2;
3351         if (flags & EXT4_GET_BLOCKS_CONVERT)
3352                 split_flag |= EXT4_EXT_DATA_VALID2;
3353         flags |= EXT4_GET_BLOCKS_PRE_IO;
3354         return ext4_split_extent(handle, inode, path, map, split_flag, flags);
3355 }
3356
3357 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3358                                                 struct inode *inode,
3359                                                 struct ext4_map_blocks *map,
3360                                                 struct ext4_ext_path *path)
3361 {
3362         struct ext4_extent *ex;
3363         ext4_lblk_t ee_block;
3364         unsigned int ee_len;
3365         int depth;
3366         int err = 0;
3367
3368         depth = ext_depth(inode);
3369         ex = path[depth].p_ext;
3370         ee_block = le32_to_cpu(ex->ee_block);
3371         ee_len = ext4_ext_get_actual_len(ex);
3372
3373         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3374                 "block %llu, max_blocks %u\n", inode->i_ino,
3375                   (unsigned long long)ee_block, ee_len);
3376
3377         /* If extent is larger than requested then split is required */
3378         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3379                 err = ext4_split_unwritten_extents(handle, inode, map, path,
3380                                                    EXT4_GET_BLOCKS_CONVERT);
3381                 if (err < 0)
3382                         goto out;
3383                 ext4_ext_drop_refs(path);
3384                 path = ext4_ext_find_extent(inode, map->m_lblk, path);
3385                 if (IS_ERR(path)) {
3386                         err = PTR_ERR(path);
3387                         goto out;
3388                 }
3389                 depth = ext_depth(inode);
3390                 ex = path[depth].p_ext;
3391         }
3392
3393         err = ext4_ext_get_access(handle, inode, path + depth);
3394         if (err)
3395                 goto out;
3396         /* first mark the extent as initialized */
3397         ext4_ext_mark_initialized(ex);
3398
3399         /* note: ext4_ext_correct_indexes() isn't needed here because
3400          * borders are not changed
3401          */
3402         ext4_ext_try_to_merge(handle, inode, path, ex);
3403
3404         /* Mark modified extent as dirty */
3405         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3406 out:
3407         ext4_ext_show_leaf(inode, path);
3408         return err;
3409 }
3410
3411 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3412                         sector_t block, int count)
3413 {
3414         int i;
3415         for (i = 0; i < count; i++)
3416                 unmap_underlying_metadata(bdev, block + i);
3417 }
3418
3419 /*
3420  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3421  */
3422 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3423                               ext4_lblk_t lblk,
3424                               struct ext4_ext_path *path,
3425                               unsigned int len)
3426 {
3427         int i, depth;
3428         struct ext4_extent_header *eh;
3429         struct ext4_extent *last_ex;
3430
3431         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3432                 return 0;
3433
3434         depth = ext_depth(inode);
3435         eh = path[depth].p_hdr;
3436
3437         /*
3438          * We're going to remove EOFBLOCKS_FL entirely in future so we
3439          * do not care for this case anymore. Simply remove the flag
3440          * if there are no extents.
3441          */
3442         if (unlikely(!eh->eh_entries))
3443                 goto out;
3444         last_ex = EXT_LAST_EXTENT(eh);
3445         /*
3446          * We should clear the EOFBLOCKS_FL flag if we are writing the
3447          * last block in the last extent in the file.  We test this by
3448          * first checking to see if the caller to
3449          * ext4_ext_get_blocks() was interested in the last block (or
3450          * a block beyond the last block) in the current extent.  If
3451          * this turns out to be false, we can bail out from this
3452          * function immediately.
3453          */
3454         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3455             ext4_ext_get_actual_len(last_ex))
3456                 return 0;
3457         /*
3458          * If the caller does appear to be planning to write at or
3459          * beyond the end of the current extent, we then test to see
3460          * if the current extent is the last extent in the file, by
3461          * checking to make sure it was reached via the rightmost node
3462          * at each level of the tree.
3463          */
3464         for (i = depth-1; i >= 0; i--)
3465                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3466                         return 0;
3467 out:
3468         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3469         return ext4_mark_inode_dirty(handle, inode);
3470 }
3471
3472 /**
3473  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3474  *
3475  * Return 1 if there is a delalloc block in the range, otherwise 0.
3476  */
3477 int ext4_find_delalloc_range(struct inode *inode,
3478                              ext4_lblk_t lblk_start,
3479                              ext4_lblk_t lblk_end)
3480 {
3481         struct extent_status es;
3482
3483         ext4_es_find_delayed_extent(inode, lblk_start, &es);
3484         if (es.es_len == 0)
3485                 return 0; /* there is no delay extent in this tree */
3486         else if (es.es_lblk <= lblk_start &&
3487                  lblk_start < es.es_lblk + es.es_len)
3488                 return 1;
3489         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3490                 return 1;
3491         else
3492                 return 0;
3493 }
3494
3495 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3496 {
3497         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3498         ext4_lblk_t lblk_start, lblk_end;
3499         lblk_start = lblk & (~(sbi->s_cluster_ratio - 1));
3500         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3501
3502         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3503 }
3504
3505 /**
3506  * Determines how many complete clusters (out of those specified by the 'map')
3507  * are under delalloc and were reserved quota for.
3508  * This function is called when we are writing out the blocks that were
3509  * originally written with their allocation delayed, but then the space was
3510  * allocated using fallocate() before the delayed allocation could be resolved.
3511  * The cases to look for are:
3512  * ('=' indicated delayed allocated blocks
3513  *  '-' indicates non-delayed allocated blocks)
3514  * (a) partial clusters towards beginning and/or end outside of allocated range
3515  *     are not delalloc'ed.
3516  *      Ex:
3517  *      |----c---=|====c====|====c====|===-c----|
3518  *               |++++++ allocated ++++++|
3519  *      ==> 4 complete clusters in above example
3520  *
3521  * (b) partial cluster (outside of allocated range) towards either end is
3522  *     marked for delayed allocation. In this case, we will exclude that
3523  *     cluster.
3524  *      Ex:
3525  *      |----====c========|========c========|
3526  *           |++++++ allocated ++++++|
3527  *      ==> 1 complete clusters in above example
3528  *
3529  *      Ex:
3530  *      |================c================|
3531  *            |++++++ allocated ++++++|
3532  *      ==> 0 complete clusters in above example
3533  *
3534  * The ext4_da_update_reserve_space will be called only if we
3535  * determine here that there were some "entire" clusters that span
3536  * this 'allocated' range.
3537  * In the non-bigalloc case, this function will just end up returning num_blks
3538  * without ever calling ext4_find_delalloc_range.
3539  */
3540 static unsigned int
3541 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3542                            unsigned int num_blks)
3543 {
3544         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3545         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3546         ext4_lblk_t lblk_from, lblk_to, c_offset;
3547         unsigned int allocated_clusters = 0;
3548
3549         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3550         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3551
3552         /* max possible clusters for this allocation */
3553         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3554
3555         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3556
3557         /* Check towards left side */
3558         c_offset = lblk_start & (sbi->s_cluster_ratio - 1);
3559         if (c_offset) {
3560                 lblk_from = lblk_start & (~(sbi->s_cluster_ratio - 1));
3561                 lblk_to = lblk_from + c_offset - 1;
3562
3563                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3564                         allocated_clusters--;
3565         }
3566
3567         /* Now check towards right. */
3568         c_offset = (lblk_start + num_blks) & (sbi->s_cluster_ratio - 1);
3569         if (allocated_clusters && c_offset) {
3570                 lblk_from = lblk_start + num_blks;
3571                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3572
3573                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3574                         allocated_clusters--;
3575         }
3576
3577         return allocated_clusters;
3578 }
3579
3580 static int
3581 ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
3582                         struct ext4_map_blocks *map,
3583                         struct ext4_ext_path *path, int flags,
3584                         unsigned int allocated, ext4_fsblk_t newblock)
3585 {
3586         int ret = 0;
3587         int err = 0;
3588         ext4_io_end_t *io = ext4_inode_aio(inode);
3589
3590         ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical "
3591                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
3592                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
3593                   flags, allocated);
3594         ext4_ext_show_leaf(inode, path);
3595
3596         trace_ext4_ext_handle_uninitialized_extents(inode, map, flags,
3597                                                     allocated, newblock);
3598
3599         /* get_block() before submit the IO, split the extent */
3600         if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3601                 ret = ext4_split_unwritten_extents(handle, inode, map,
3602                                                    path, flags);
3603                 if (ret <= 0)
3604                         goto out;
3605                 /*
3606                  * Flag the inode(non aio case) or end_io struct (aio case)
3607                  * that this IO needs to conversion to written when IO is
3608                  * completed
3609                  */
3610                 if (io)
3611                         ext4_set_io_unwritten_flag(inode, io);
3612                 else
3613                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3614                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3615                 if (ext4_should_dioread_nolock(inode))
3616                         map->m_flags |= EXT4_MAP_UNINIT;
3617                 goto out;
3618         }
3619         /* IO end_io complete, convert the filled extent to written */
3620         if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
3621                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
3622                                                         path);
3623                 if (ret >= 0) {
3624                         ext4_update_inode_fsync_trans(handle, inode, 1);
3625                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
3626                                                  path, map->m_len);
3627                 } else
3628                         err = ret;
3629                 goto out2;
3630         }
3631         /* buffered IO case */
3632         /*
3633          * repeat fallocate creation request
3634          * we already have an unwritten extent
3635          */
3636         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT) {
3637                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3638                 goto map_out;
3639         }
3640
3641         /* buffered READ or buffered write_begin() lookup */
3642         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3643                 /*
3644                  * We have blocks reserved already.  We
3645                  * return allocated blocks so that delalloc
3646                  * won't do block reservation for us.  But
3647                  * the buffer head will be unmapped so that
3648                  * a read from the block returns 0s.
3649                  */
3650                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3651                 goto out1;
3652         }
3653
3654         /* buffered write, writepage time, convert*/
3655         ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
3656         if (ret >= 0)
3657                 ext4_update_inode_fsync_trans(handle, inode, 1);
3658 out:
3659         if (ret <= 0) {
3660                 err = ret;
3661                 goto out2;
3662         } else
3663                 allocated = ret;
3664         map->m_flags |= EXT4_MAP_NEW;
3665         /*
3666          * if we allocated more blocks than requested
3667          * we need to make sure we unmap the extra block
3668          * allocated. The actual needed block will get
3669          * unmapped later when we find the buffer_head marked
3670          * new.
3671          */
3672         if (allocated > map->m_len) {
3673                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
3674                                         newblock + map->m_len,
3675                                         allocated - map->m_len);
3676                 allocated = map->m_len;
3677         }
3678
3679         /*
3680          * If we have done fallocate with the offset that is already
3681          * delayed allocated, we would have block reservation
3682          * and quota reservation done in the delayed write path.
3683          * But fallocate would have already updated quota and block
3684          * count for this offset. So cancel these reservation
3685          */
3686         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
3687                 unsigned int reserved_clusters;
3688                 reserved_clusters = get_reserved_cluster_alloc(inode,
3689                                 map->m_lblk, map->m_len);
3690                 if (reserved_clusters)
3691                         ext4_da_update_reserve_space(inode,
3692                                                      reserved_clusters,
3693                                                      0);
3694         }
3695
3696 map_out:
3697         map->m_flags |= EXT4_MAP_MAPPED;
3698         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
3699                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
3700                                          map->m_len);
3701                 if (err < 0)
3702                         goto out2;
3703         }
3704 out1:
3705         if (allocated > map->m_len)
3706                 allocated = map->m_len;
3707         ext4_ext_show_leaf(inode, path);
3708         map->m_pblk = newblock;
3709         map->m_len = allocated;
3710 out2:
3711         if (path) {
3712                 ext4_ext_drop_refs(path);
3713                 kfree(path);
3714         }
3715         return err ? err : allocated;
3716 }
3717
3718 /*
3719  * get_implied_cluster_alloc - check to see if the requested
3720  * allocation (in the map structure) overlaps with a cluster already
3721  * allocated in an extent.
3722  *      @sb     The filesystem superblock structure
3723  *      @map    The requested lblk->pblk mapping
3724  *      @ex     The extent structure which might contain an implied
3725  *                      cluster allocation
3726  *
3727  * This function is called by ext4_ext_map_blocks() after we failed to
3728  * find blocks that were already in the inode's extent tree.  Hence,
3729  * we know that the beginning of the requested region cannot overlap
3730  * the extent from the inode's extent tree.  There are three cases we
3731  * want to catch.  The first is this case:
3732  *
3733  *               |--- cluster # N--|
3734  *    |--- extent ---|  |---- requested region ---|
3735  *                      |==========|
3736  *
3737  * The second case that we need to test for is this one:
3738  *
3739  *   |--------- cluster # N ----------------|
3740  *         |--- requested region --|   |------- extent ----|
3741  *         |=======================|
3742  *
3743  * The third case is when the requested region lies between two extents
3744  * within the same cluster:
3745  *          |------------- cluster # N-------------|
3746  * |----- ex -----|                  |---- ex_right ----|
3747  *                  |------ requested region ------|
3748  *                  |================|
3749  *
3750  * In each of the above cases, we need to set the map->m_pblk and
3751  * map->m_len so it corresponds to the return the extent labelled as
3752  * "|====|" from cluster #N, since it is already in use for data in
3753  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
3754  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
3755  * as a new "allocated" block region.  Otherwise, we will return 0 and
3756  * ext4_ext_map_blocks() will then allocate one or more new clusters
3757  * by calling ext4_mb_new_blocks().
3758  */
3759 static int get_implied_cluster_alloc(struct super_block *sb,
3760                                      struct ext4_map_blocks *map,
3761                                      struct ext4_extent *ex,
3762                                      struct ext4_ext_path *path)
3763 {
3764         struct ext4_sb_info *sbi = EXT4_SB(sb);
3765         ext4_lblk_t c_offset = map->m_lblk & (sbi->s_cluster_ratio-1);
3766         ext4_lblk_t ex_cluster_start, ex_cluster_end;
3767         ext4_lblk_t rr_cluster_start;
3768         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3769         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3770         unsigned short ee_len = ext4_ext_get_actual_len(ex);
3771
3772         /* The extent passed in that we are trying to match */
3773         ex_cluster_start = EXT4_B2C(sbi, ee_block);
3774         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
3775
3776         /* The requested region passed into ext4_map_blocks() */
3777         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
3778
3779         if ((rr_cluster_start == ex_cluster_end) ||
3780             (rr_cluster_start == ex_cluster_start)) {
3781                 if (rr_cluster_start == ex_cluster_end)
3782                         ee_start += ee_len - 1;
3783                 map->m_pblk = (ee_start & ~(sbi->s_cluster_ratio - 1)) +
3784                         c_offset;
3785                 map->m_len = min(map->m_len,
3786                                  (unsigned) sbi->s_cluster_ratio - c_offset);
3787                 /*
3788                  * Check for and handle this case:
3789                  *
3790                  *   |--------- cluster # N-------------|
3791                  *                     |------- extent ----|
3792                  *         |--- requested region ---|
3793                  *         |===========|
3794                  */
3795
3796                 if (map->m_lblk < ee_block)
3797                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
3798
3799                 /*
3800                  * Check for the case where there is already another allocated
3801                  * block to the right of 'ex' but before the end of the cluster.
3802                  *
3803                  *          |------------- cluster # N-------------|
3804                  * |----- ex -----|                  |---- ex_right ----|
3805                  *                  |------ requested region ------|
3806                  *                  |================|
3807                  */
3808                 if (map->m_lblk > ee_block) {
3809                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
3810                         map->m_len = min(map->m_len, next - map->m_lblk);
3811                 }
3812
3813                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
3814                 return 1;
3815         }
3816
3817         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
3818         return 0;
3819 }
3820
3821
3822 /*
3823  * Block allocation/map/preallocation routine for extents based files
3824  *
3825  *
3826  * Need to be called with
3827  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
3828  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
3829  *
3830  * return > 0, number of of blocks already mapped/allocated
3831  *          if create == 0 and these are pre-allocated blocks
3832  *              buffer head is unmapped
3833  *          otherwise blocks are mapped
3834  *
3835  * return = 0, if plain look up failed (blocks have not been allocated)
3836  *          buffer head is unmapped
3837  *
3838  * return < 0, error case.
3839  */
3840 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
3841                         struct ext4_map_blocks *map, int flags)
3842 {
3843         struct ext4_ext_path *path = NULL;
3844         struct ext4_extent newex, *ex, *ex2;
3845         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3846         ext4_fsblk_t newblock = 0;
3847         int free_on_err = 0, err = 0, depth;
3848         unsigned int allocated = 0, offset = 0;
3849         unsigned int allocated_clusters = 0;
3850         struct ext4_allocation_request ar;
3851         ext4_io_end_t *io = ext4_inode_aio(inode);
3852         ext4_lblk_t cluster_offset;
3853         int set_unwritten = 0;
3854
3855         ext_debug("blocks %u/%u requested for inode %lu\n",
3856                   map->m_lblk, map->m_len, inode->i_ino);
3857         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
3858
3859         /* find extent for this block */
3860         path = ext4_ext_find_extent(inode, map->m_lblk, NULL);
3861         if (IS_ERR(path)) {
3862                 err = PTR_ERR(path);
3863                 path = NULL;
3864                 goto out2;
3865         }
3866
3867         depth = ext_depth(inode);
3868
3869         /*
3870          * consistent leaf must not be empty;
3871          * this situation is possible, though, _during_ tree modification;
3872          * this is why assert can't be put in ext4_ext_find_extent()
3873          */
3874         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
3875                 EXT4_ERROR_INODE(inode, "bad extent address "
3876                                  "lblock: %lu, depth: %d pblock %lld",
3877                                  (unsigned long) map->m_lblk, depth,
3878                                  path[depth].p_block);
3879                 err = -EIO;
3880                 goto out2;
3881         }
3882
3883         ex = path[depth].p_ext;
3884         if (ex) {
3885                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3886                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3887                 unsigned short ee_len;
3888
3889                 /*
3890                  * Uninitialized extents are treated as holes, except that
3891                  * we split out initialized portions during a write.
3892                  */
3893                 ee_len = ext4_ext_get_actual_len(ex);
3894
3895                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
3896
3897                 /* if found extent covers block, simply return it */
3898                 if (in_range(map->m_lblk, ee_block, ee_len)) {
3899                         newblock = map->m_lblk - ee_block + ee_start;
3900                         /* number of remaining blocks in the extent */
3901                         allocated = ee_len - (map->m_lblk - ee_block);
3902                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
3903                                   ee_block, ee_len, newblock);
3904
3905                         if (!ext4_ext_is_uninitialized(ex))
3906                                 goto out;
3907
3908                         allocated = ext4_ext_handle_uninitialized_extents(
3909                                 handle, inode, map, path, flags,
3910                                 allocated, newblock);
3911                         goto out3;
3912                 }
3913         }
3914
3915         if ((sbi->s_cluster_ratio > 1) &&
3916             ext4_find_delalloc_cluster(inode, map->m_lblk))
3917                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
3918
3919         /*
3920          * requested block isn't allocated yet;
3921          * we couldn't try to create block if create flag is zero
3922          */
3923         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3924                 /*
3925                  * put just found gap into cache to speed up
3926                  * subsequent requests
3927                  */
3928                 if ((flags & EXT4_GET_BLOCKS_NO_PUT_HOLE) == 0)
3929                         ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
3930                 goto out2;
3931         }
3932
3933         /*
3934          * Okay, we need to do block allocation.
3935          */
3936         map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
3937         newex.ee_block = cpu_to_le32(map->m_lblk);
3938         cluster_offset = map->m_lblk & (sbi->s_cluster_ratio-1);
3939
3940         /*
3941          * If we are doing bigalloc, check to see if the extent returned
3942          * by ext4_ext_find_extent() implies a cluster we can use.
3943          */
3944         if (cluster_offset && ex &&
3945             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
3946                 ar.len = allocated = map->m_len;
3947                 newblock = map->m_pblk;
3948                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
3949                 goto got_allocated_blocks;
3950         }
3951
3952         /* find neighbour allocated blocks */
3953         ar.lleft = map->m_lblk;
3954         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
3955         if (err)
3956                 goto out2;
3957         ar.lright = map->m_lblk;
3958         ex2 = NULL;
3959         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
3960         if (err)
3961                 goto out2;
3962
3963         /* Check if the extent after searching to the right implies a
3964          * cluster we can use. */
3965         if ((sbi->s_cluster_ratio > 1) && ex2 &&
3966             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
3967                 ar.len = allocated = map->m_len;
3968                 newblock = map->m_pblk;
3969                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
3970                 goto got_allocated_blocks;
3971         }
3972
3973         /*
3974          * See if request is beyond maximum number of blocks we can have in
3975          * a single extent. For an initialized extent this limit is
3976          * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
3977          * EXT_UNINIT_MAX_LEN.
3978          */
3979         if (map->m_len > EXT_INIT_MAX_LEN &&
3980             !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3981                 map->m_len = EXT_INIT_MAX_LEN;
3982         else if (map->m_len > EXT_UNINIT_MAX_LEN &&
3983                  (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3984                 map->m_len = EXT_UNINIT_MAX_LEN;
3985
3986         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
3987         newex.ee_len = cpu_to_le16(map->m_len);
3988         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
3989         if (err)
3990                 allocated = ext4_ext_get_actual_len(&newex);
3991         else
3992                 allocated = map->m_len;
3993
3994         /* allocate new block */
3995         ar.inode = inode;
3996         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
3997         ar.logical = map->m_lblk;
3998         /*
3999          * We calculate the offset from the beginning of the cluster
4000          * for the logical block number, since when we allocate a
4001          * physical cluster, the physical block should start at the
4002          * same offset from the beginning of the cluster.  This is
4003          * needed so that future calls to get_implied_cluster_alloc()
4004          * work correctly.
4005          */
4006         offset = map->m_lblk & (sbi->s_cluster_ratio - 1);
4007         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4008         ar.goal -= offset;
4009         ar.logical -= offset;
4010         if (S_ISREG(inode->i_mode))
4011                 ar.flags = EXT4_MB_HINT_DATA;
4012         else
4013                 /* disable in-core preallocation for non-regular files */
4014                 ar.flags = 0;
4015         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4016                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4017         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4018         if (!newblock)
4019                 goto out2;
4020         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4021                   ar.goal, newblock, allocated);
4022         free_on_err = 1;
4023         allocated_clusters = ar.len;
4024         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4025         if (ar.len > allocated)
4026                 ar.len = allocated;
4027
4028 got_allocated_blocks:
4029         /* try to insert new extent into found leaf and return */
4030         ext4_ext_store_pblock(&newex, newblock + offset);
4031         newex.ee_len = cpu_to_le16(ar.len);
4032         /* Mark uninitialized */
4033         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
4034                 ext4_ext_mark_uninitialized(&newex);
4035                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4036                 /*
4037                  * io_end structure was created for every IO write to an
4038                  * uninitialized extent. To avoid unnecessary conversion,
4039                  * here we flag the IO that really needs the conversion.
4040                  * For non asycn direct IO case, flag the inode state
4041                  * that we need to perform conversion when IO is done.
4042                  */
4043                 if ((flags & EXT4_GET_BLOCKS_PRE_IO))
4044                         set_unwritten = 1;
4045                 if (ext4_should_dioread_nolock(inode))
4046                         map->m_flags |= EXT4_MAP_UNINIT;
4047         }
4048
4049         err = 0;
4050         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4051                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4052                                          path, ar.len);
4053         if (!err)
4054                 err = ext4_ext_insert_extent(handle, inode, path,
4055                                              &newex, flags);
4056
4057         if (!err && set_unwritten) {
4058                 if (io)
4059                         ext4_set_io_unwritten_flag(inode, io);
4060                 else
4061                         ext4_set_inode_state(inode,
4062                                              EXT4_STATE_DIO_UNWRITTEN);
4063         }
4064
4065         if (err && free_on_err) {
4066                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4067                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4068                 /* free data blocks we just allocated */
4069                 /* not a good idea to call discard here directly,
4070                  * but otherwise we'd need to call it every free() */
4071                 ext4_discard_preallocations(inode);
4072                 ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex),
4073                                  ext4_ext_get_actual_len(&newex), fb_flags);
4074                 goto out2;
4075         }
4076
4077         /* previous routine could use block we allocated */
4078         newblock = ext4_ext_pblock(&newex);
4079         allocated = ext4_ext_get_actual_len(&newex);
4080         if (allocated > map->m_len)
4081                 allocated = map->m_len;
4082         map->m_flags |= EXT4_MAP_NEW;
4083
4084         /*
4085          * Update reserved blocks/metadata blocks after successful
4086          * block allocation which had been deferred till now.
4087          */
4088         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4089                 unsigned int reserved_clusters;
4090                 /*
4091                  * Check how many clusters we had reserved this allocated range
4092                  */
4093                 reserved_clusters = get_reserved_cluster_alloc(inode,
4094                                                 map->m_lblk, allocated);
4095                 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) {
4096                         if (reserved_clusters) {
4097                                 /*
4098                                  * We have clusters reserved for this range.
4099                                  * But since we are not doing actual allocation
4100                                  * and are simply using blocks from previously
4101                                  * allocated cluster, we should release the
4102                                  * reservation and not claim quota.
4103                                  */
4104                                 ext4_da_update_reserve_space(inode,
4105                                                 reserved_clusters, 0);
4106                         }
4107                 } else {
4108                         BUG_ON(allocated_clusters < reserved_clusters);
4109                         /* We will claim quota for all newly allocated blocks.*/
4110                         ext4_da_update_reserve_space(inode, allocated_clusters,
4111                                                         1);
4112                         if (reserved_clusters < allocated_clusters) {
4113                                 struct ext4_inode_info *ei = EXT4_I(inode);
4114                                 int reservation = allocated_clusters -
4115                                                   reserved_clusters;
4116                                 /*
4117                                  * It seems we claimed few clusters outside of
4118                                  * the range of this allocation. We should give
4119                                  * it back to the reservation pool. This can
4120                                  * happen in the following case:
4121                                  *
4122                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4123                                  *   cluster has 4 blocks. Thus, the clusters
4124                                  *   are [0-3],[4-7],[8-11]...
4125                                  * * First comes delayed allocation write for
4126                                  *   logical blocks 10 & 11. Since there were no
4127                                  *   previous delayed allocated blocks in the
4128                                  *   range [8-11], we would reserve 1 cluster
4129                                  *   for this write.
4130                                  * * Next comes write for logical blocks 3 to 8.
4131                                  *   In this case, we will reserve 2 clusters
4132                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4133                                  *   that range has a delayed allocated blocks.
4134                                  *   Thus total reserved clusters now becomes 3.
4135                                  * * Now, during the delayed allocation writeout
4136                                  *   time, we will first write blocks [3-8] and
4137                                  *   allocate 3 clusters for writing these
4138                                  *   blocks. Also, we would claim all these
4139                                  *   three clusters above.
4140                                  * * Now when we come here to writeout the
4141                                  *   blocks [10-11], we would expect to claim
4142                                  *   the reservation of 1 cluster we had made
4143                                  *   (and we would claim it since there are no
4144                                  *   more delayed allocated blocks in the range
4145                                  *   [8-11]. But our reserved cluster count had
4146                                  *   already gone to 0.
4147                                  *
4148                                  *   Thus, at the step 4 above when we determine
4149                                  *   that there are still some unwritten delayed
4150                                  *   allocated blocks outside of our current
4151                                  *   block range, we should increment the
4152                                  *   reserved clusters count so that when the
4153                                  *   remaining blocks finally gets written, we
4154                                  *   could claim them.
4155                                  */
4156                                 dquot_reserve_block(inode,
4157                                                 EXT4_C2B(sbi, reservation));
4158                                 spin_lock(&ei->i_block_reservation_lock);
4159                                 ei->i_reserved_data_blocks += reservation;
4160                                 spin_unlock(&ei->i_block_reservation_lock);
4161                         }
4162                 }
4163         }
4164
4165         /*
4166          * Cache the extent and update transaction to commit on fdatasync only
4167          * when it is _not_ an uninitialized extent.
4168          */
4169         if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0)
4170                 ext4_update_inode_fsync_trans(handle, inode, 1);
4171         else
4172                 ext4_update_inode_fsync_trans(handle, inode, 0);
4173 out:
4174         if (allocated > map->m_len)
4175                 allocated = map->m_len;
4176         ext4_ext_show_leaf(inode, path);
4177         map->m_flags |= EXT4_MAP_MAPPED;
4178         map->m_pblk = newblock;
4179         map->m_len = allocated;
4180 out2:
4181         if (path) {
4182                 ext4_ext_drop_refs(path);
4183                 kfree(path);
4184         }
4185
4186 out3:
4187         trace_ext4_ext_map_blocks_exit(inode, map, err ? err : allocated);
4188
4189         return err ? err : allocated;
4190 }
4191
4192 void ext4_ext_truncate(struct inode *inode)
4193 {
4194         struct address_space *mapping = inode->i_mapping;
4195         struct super_block *sb = inode->i_sb;
4196         ext4_lblk_t last_block;
4197         handle_t *handle;
4198         loff_t page_len;
4199         int err = 0;
4200
4201         /*
4202          * finish any pending end_io work so we won't run the risk of
4203          * converting any truncated blocks to initialized later
4204          */
4205         ext4_flush_unwritten_io(inode);
4206
4207         /*
4208          * probably first extent we're gonna free will be last in block
4209          */
4210         err = ext4_writepage_trans_blocks(inode);
4211         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, err);
4212         if (IS_ERR(handle))
4213                 return;
4214
4215         if (inode->i_size % PAGE_CACHE_SIZE != 0) {
4216                 page_len = PAGE_CACHE_SIZE -
4217                         (inode->i_size & (PAGE_CACHE_SIZE - 1));
4218
4219                 err = ext4_discard_partial_page_buffers(handle,
4220                         mapping, inode->i_size, page_len, 0);
4221
4222                 if (err)
4223                         goto out_stop;
4224         }
4225
4226         if (ext4_orphan_add(handle, inode))
4227                 goto out_stop;
4228
4229         down_write(&EXT4_I(inode)->i_data_sem);
4230
4231         ext4_discard_preallocations(inode);
4232
4233         /*
4234          * TODO: optimization is possible here.
4235          * Probably we need not scan at all,
4236          * because page truncation is enough.
4237          */
4238
4239         /* we have to know where to truncate from in crash case */
4240         EXT4_I(inode)->i_disksize = inode->i_size;
4241         ext4_mark_inode_dirty(handle, inode);
4242
4243         last_block = (inode->i_size + sb->s_blocksize - 1)
4244                         >> EXT4_BLOCK_SIZE_BITS(sb);
4245         err = ext4_es_remove_extent(inode, last_block,
4246                                     EXT_MAX_BLOCKS - last_block);
4247         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4248
4249         /* In a multi-transaction truncate, we only make the final
4250          * transaction synchronous.
4251          */
4252         if (IS_SYNC(inode))
4253                 ext4_handle_sync(handle);
4254
4255         up_write(&EXT4_I(inode)->i_data_sem);
4256
4257 out_stop:
4258         /*
4259          * If this was a simple ftruncate() and the file will remain alive,
4260          * then we need to clear up the orphan record which we created above.
4261          * However, if this was a real unlink then we were called by
4262          * ext4_delete_inode(), and we allow that function to clean up the
4263          * orphan info for us.
4264          */
4265         if (inode->i_nlink)
4266                 ext4_orphan_del(handle, inode);
4267
4268         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4269         ext4_mark_inode_dirty(handle, inode);
4270         ext4_journal_stop(handle);
4271 }
4272
4273 static void ext4_falloc_update_inode(struct inode *inode,
4274                                 int mode, loff_t new_size, int update_ctime)
4275 {
4276         struct timespec now;
4277
4278         if (update_ctime) {
4279                 now = current_fs_time(inode->i_sb);
4280                 if (!timespec_equal(&inode->i_ctime, &now))
4281                         inode->i_ctime = now;
4282         }
4283         /*
4284          * Update only when preallocation was requested beyond
4285          * the file size.
4286          */
4287         if (!(mode & FALLOC_FL_KEEP_SIZE)) {
4288                 if (new_size > i_size_read(inode))
4289                         i_size_write(inode, new_size);
4290                 if (new_size > EXT4_I(inode)->i_disksize)
4291                         ext4_update_i_disksize(inode, new_size);
4292         } else {
4293                 /*
4294                  * Mark that we allocate beyond EOF so the subsequent truncate
4295                  * can proceed even if the new size is the same as i_size.
4296                  */
4297                 if (new_size > i_size_read(inode))
4298                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4299         }
4300
4301 }
4302
4303 /*
4304  * preallocate space for a file. This implements ext4's fallocate file
4305  * operation, which gets called from sys_fallocate system call.
4306  * For block-mapped files, posix_fallocate should fall back to the method
4307  * of writing zeroes to the required new blocks (the same behavior which is
4308  * expected for file systems which do not support fallocate() system call).
4309  */
4310 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4311 {
4312         struct inode *inode = file_inode(file);
4313         handle_t *handle;
4314         loff_t new_size;
4315         unsigned int max_blocks;
4316         int ret = 0;
4317         int ret2 = 0;
4318         int retries = 0;
4319         int flags;
4320         struct ext4_map_blocks map;
4321         unsigned int credits, blkbits = inode->i_blkbits;
4322
4323         /* Return error if mode is not supported */
4324         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
4325                 return -EOPNOTSUPP;
4326
4327         if (mode & FALLOC_FL_PUNCH_HOLE)
4328                 return ext4_punch_hole(file, offset, len);
4329
4330         ret = ext4_convert_inline_data(inode);
4331         if (ret)
4332                 return ret;
4333
4334         /*
4335          * currently supporting (pre)allocate mode for extent-based
4336          * files _only_
4337          */
4338         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4339                 return -EOPNOTSUPP;
4340
4341         trace_ext4_fallocate_enter(inode, offset, len, mode);
4342         map.m_lblk = offset >> blkbits;
4343         /*
4344          * We can't just convert len to max_blocks because
4345          * If blocksize = 4096 offset = 3072 and len = 2048
4346          */
4347         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4348                 - map.m_lblk;
4349         /*
4350          * credits to insert 1 extent into extent tree
4351          */
4352         credits = ext4_chunk_trans_blocks(inode, max_blocks);
4353         mutex_lock(&inode->i_mutex);
4354         ret = inode_newsize_ok(inode, (len + offset));
4355         if (ret) {
4356                 mutex_unlock(&inode->i_mutex);
4357                 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4358                 return ret;
4359         }
4360         flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT;
4361         if (mode & FALLOC_FL_KEEP_SIZE)
4362                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4363         /*
4364          * Don't normalize the request if it can fit in one extent so
4365          * that it doesn't get unnecessarily split into multiple
4366          * extents.
4367          */
4368         if (len <= EXT_UNINIT_MAX_LEN << blkbits)
4369                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4370
4371         /* Prevent race condition between unwritten */
4372         ext4_flush_unwritten_io(inode);
4373 retry:
4374         while (ret >= 0 && ret < max_blocks) {
4375                 map.m_lblk = map.m_lblk + ret;
4376                 map.m_len = max_blocks = max_blocks - ret;
4377                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4378                                             credits);
4379                 if (IS_ERR(handle)) {
4380                         ret = PTR_ERR(handle);
4381                         break;
4382                 }
4383                 ret = ext4_map_blocks(handle, inode, &map, flags);
4384                 if (ret <= 0) {
4385 #ifdef EXT4FS_DEBUG
4386                         ext4_warning(inode->i_sb,
4387                                      "inode #%lu: block %u: len %u: "
4388                                      "ext4_ext_map_blocks returned %d",
4389                                      inode->i_ino, map.m_lblk,
4390                                      map.m_len, ret);
4391 #endif
4392                         ext4_mark_inode_dirty(handle, inode);
4393                         ret2 = ext4_journal_stop(handle);
4394                         break;
4395                 }
4396                 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
4397                                                 blkbits) >> blkbits))
4398                         new_size = offset + len;
4399                 else
4400                         new_size = ((loff_t) map.m_lblk + ret) << blkbits;
4401
4402                 ext4_falloc_update_inode(inode, mode, new_size,
4403                                          (map.m_flags & EXT4_MAP_NEW));
4404                 ext4_mark_inode_dirty(handle, inode);
4405                 if ((file->f_flags & O_SYNC) && ret >= max_blocks)
4406                         ext4_handle_sync(handle);
4407                 ret2 = ext4_journal_stop(handle);
4408                 if (ret2)
4409                         break;
4410         }
4411         if (ret == -ENOSPC &&
4412                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4413                 ret = 0;
4414                 goto retry;
4415         }
4416         mutex_unlock(&inode->i_mutex);
4417         trace_ext4_fallocate_exit(inode, offset, max_blocks,
4418                                 ret > 0 ? ret2 : ret);
4419         return ret > 0 ? ret2 : ret;
4420 }
4421
4422 /*
4423  * This function convert a range of blocks to written extents
4424  * The caller of this function will pass the start offset and the size.
4425  * all unwritten extents within this range will be converted to
4426  * written extents.
4427  *
4428  * This function is called from the direct IO end io call back
4429  * function, to convert the fallocated extents after IO is completed.
4430  * Returns 0 on success.
4431  */
4432 int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
4433                                     ssize_t len)
4434 {
4435         handle_t *handle;
4436         unsigned int max_blocks;
4437         int ret = 0;
4438         int ret2 = 0;
4439         struct ext4_map_blocks map;
4440         unsigned int credits, blkbits = inode->i_blkbits;
4441
4442         map.m_lblk = offset >> blkbits;
4443         /*
4444          * We can't just convert len to max_blocks because
4445          * If blocksize = 4096 offset = 3072 and len = 2048
4446          */
4447         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
4448                       map.m_lblk);
4449         /*
4450          * credits to insert 1 extent into extent tree
4451          */
4452         credits = ext4_chunk_trans_blocks(inode, max_blocks);
4453         while (ret >= 0 && ret < max_blocks) {
4454                 map.m_lblk += ret;
4455                 map.m_len = (max_blocks -= ret);
4456                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, credits);
4457                 if (IS_ERR(handle)) {
4458                         ret = PTR_ERR(handle);
4459                         break;
4460                 }
4461                 ret = ext4_map_blocks(handle, inode, &map,
4462                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4463                 if (ret <= 0)
4464                         ext4_warning(inode->i_sb,
4465                                      "inode #%lu: block %u: len %u: "
4466                                      "ext4_ext_map_blocks returned %d",
4467                                      inode->i_ino, map.m_lblk,
4468                                      map.m_len, ret);
4469                 ext4_mark_inode_dirty(handle, inode);
4470                 ret2 = ext4_journal_stop(handle);
4471                 if (ret <= 0 || ret2 )
4472                         break;
4473         }
4474         return ret > 0 ? ret2 : ret;
4475 }
4476
4477 /*
4478  * If newes is not existing extent (newes->ec_pblk equals zero) find
4479  * delayed extent at start of newes and update newes accordingly and
4480  * return start of the next delayed extent.
4481  *
4482  * If newes is existing extent (newes->ec_pblk is not equal zero)
4483  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
4484  * extent found. Leave newes unmodified.
4485  */
4486 static int ext4_find_delayed_extent(struct inode *inode,
4487                                     struct extent_status *newes)
4488 {
4489         struct extent_status es;
4490         ext4_lblk_t block, next_del;
4491
4492         ext4_es_find_delayed_extent(inode, newes->es_lblk, &es);
4493
4494         if (newes->es_pblk == 0) {
4495                 /*
4496                  * No extent in extent-tree contains block @newes->es_pblk,
4497                  * then the block may stay in 1)a hole or 2)delayed-extent.
4498                  */
4499                 if (es.es_len == 0)
4500                         /* A hole found. */
4501                         return 0;
4502
4503                 if (es.es_lblk > newes->es_lblk) {
4504                         /* A hole found. */
4505                         newes->es_len = min(es.es_lblk - newes->es_lblk,
4506                                             newes->es_len);
4507                         return 0;
4508                 }
4509
4510                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
4511         }
4512
4513         block = newes->es_lblk + newes->es_len;
4514         ext4_es_find_delayed_extent(inode, block, &es);
4515         if (es.es_len == 0)
4516                 next_del = EXT_MAX_BLOCKS;
4517         else
4518                 next_del = es.es_lblk;
4519
4520         return next_del;
4521 }
4522 /* fiemap flags we can handle specified here */
4523 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
4524
4525 static int ext4_xattr_fiemap(struct inode *inode,
4526                                 struct fiemap_extent_info *fieinfo)
4527 {
4528         __u64 physical = 0;
4529         __u64 length;
4530         __u32 flags = FIEMAP_EXTENT_LAST;
4531         int blockbits = inode->i_sb->s_blocksize_bits;
4532         int error = 0;
4533
4534         /* in-inode? */
4535         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4536                 struct ext4_iloc iloc;
4537                 int offset;     /* offset of xattr in inode */
4538
4539                 error = ext4_get_inode_loc(inode, &iloc);
4540                 if (error)
4541                         return error;
4542                 physical = iloc.bh->b_blocknr << blockbits;
4543                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4544                                 EXT4_I(inode)->i_extra_isize;
4545                 physical += offset;
4546                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4547                 flags |= FIEMAP_EXTENT_DATA_INLINE;
4548                 brelse(iloc.bh);
4549         } else { /* external block */
4550                 physical = EXT4_I(inode)->i_file_acl << blockbits;
4551                 length = inode->i_sb->s_blocksize;
4552         }
4553
4554         if (physical)
4555                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
4556                                                 length, flags);
4557         return (error < 0 ? error : 0);
4558 }
4559
4560 /*
4561  * ext4_ext_punch_hole
4562  *
4563  * Punches a hole of "length" bytes in a file starting
4564  * at byte "offset"
4565  *
4566  * @inode:  The inode of the file to punch a hole in
4567  * @offset: The starting byte offset of the hole
4568  * @length: The length of the hole
4569  *
4570  * Returns the number of blocks removed or negative on err
4571  */
4572 int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length)
4573 {
4574         struct inode *inode = file_inode(file);
4575         struct super_block *sb = inode->i_sb;
4576         ext4_lblk_t first_block, stop_block;
4577         struct address_space *mapping = inode->i_mapping;
4578         handle_t *handle;
4579         loff_t first_page, last_page, page_len;
4580         loff_t first_page_offset, last_page_offset;
4581         int credits, err = 0;
4582
4583         /*
4584          * Write out all dirty pages to avoid race conditions
4585          * Then release them.
4586          */
4587         if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4588                 err = filemap_write_and_wait_range(mapping,
4589                         offset, offset + length - 1);
4590
4591                 if (err)
4592                         return err;
4593         }
4594
4595         mutex_lock(&inode->i_mutex);
4596         /* It's not possible punch hole on append only file */
4597         if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
4598                 err = -EPERM;
4599                 goto out_mutex;
4600         }
4601         if (IS_SWAPFILE(inode)) {
4602                 err = -ETXTBSY;
4603                 goto out_mutex;
4604         }
4605
4606         /* No need to punch hole beyond i_size */
4607         if (offset >= inode->i_size)
4608                 goto out_mutex;
4609
4610         /*
4611          * If the hole extends beyond i_size, set the hole
4612          * to end after the page that contains i_size
4613          */
4614         if (offset + length > inode->i_size) {
4615                 length = inode->i_size +
4616                    PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) -
4617                    offset;
4618         }
4619
4620         first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
4621         last_page = (offset + length) >> PAGE_CACHE_SHIFT;
4622
4623         first_page_offset = first_page << PAGE_CACHE_SHIFT;
4624         last_page_offset = last_page << PAGE_CACHE_SHIFT;
4625
4626         /* Now release the pages */
4627         if (last_page_offset > first_page_offset) {
4628                 truncate_pagecache_range(inode, first_page_offset,
4629                                          last_page_offset - 1);
4630         }
4631
4632         /* Wait all existing dio workers, newcomers will block on i_mutex */
4633         ext4_inode_block_unlocked_dio(inode);
4634         err = ext4_flush_unwritten_io(inode);
4635         if (err)
4636                 goto out_dio;
4637         inode_dio_wait(inode);
4638
4639         credits = ext4_writepage_trans_blocks(inode);
4640         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4641         if (IS_ERR(handle)) {
4642                 err = PTR_ERR(handle);
4643                 goto out_dio;
4644         }
4645
4646
4647         /*
4648          * Now we need to zero out the non-page-aligned data in the
4649          * pages at the start and tail of the hole, and unmap the buffer
4650          * heads for the block aligned regions of the page that were
4651          * completely zeroed.
4652          */
4653         if (first_page > last_page) {
4654                 /*
4655                  * If the file space being truncated is contained within a page
4656                  * just zero out and unmap the middle of that page
4657                  */
4658                 err = ext4_discard_partial_page_buffers(handle,
4659                         mapping, offset, length, 0);
4660
4661                 if (err)
4662                         goto out;
4663         } else {
4664                 /*
4665                  * zero out and unmap the partial page that contains
4666                  * the start of the hole
4667                  */
4668                 page_len  = first_page_offset - offset;
4669                 if (page_len > 0) {
4670                         err = ext4_discard_partial_page_buffers(handle, mapping,
4671                                                    offset, page_len, 0);
4672                         if (err)
4673                                 goto out;
4674                 }
4675
4676                 /*
4677                  * zero out and unmap the partial page that contains
4678                  * the end of the hole
4679                  */
4680                 page_len = offset + length - last_page_offset;
4681                 if (page_len > 0) {
4682                         err = ext4_discard_partial_page_buffers(handle, mapping,
4683                                         last_page_offset, page_len, 0);
4684                         if (err)
4685                                 goto out;
4686                 }
4687         }
4688
4689         /*
4690          * If i_size is contained in the last page, we need to
4691          * unmap and zero the partial page after i_size
4692          */
4693         if (inode->i_size >> PAGE_CACHE_SHIFT == last_page &&
4694            inode->i_size % PAGE_CACHE_SIZE != 0) {
4695
4696                 page_len = PAGE_CACHE_SIZE -
4697                         (inode->i_size & (PAGE_CACHE_SIZE - 1));
4698
4699                 if (page_len > 0) {
4700                         err = ext4_discard_partial_page_buffers(handle,
4701                           mapping, inode->i_size, page_len, 0);
4702
4703                         if (err)
4704                                 goto out;
4705                 }
4706         }
4707
4708         first_block = (offset + sb->s_blocksize - 1) >>
4709                 EXT4_BLOCK_SIZE_BITS(sb);
4710         stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4711
4712         /* If there are no blocks to remove, return now */
4713         if (first_block >= stop_block)
4714                 goto out;
4715
4716         down_write(&EXT4_I(inode)->i_data_sem);
4717         ext4_discard_preallocations(inode);
4718
4719         err = ext4_es_remove_extent(inode, first_block,
4720                                     stop_block - first_block);
4721         err = ext4_ext_remove_space(inode, first_block, stop_block - 1);
4722
4723         ext4_discard_preallocations(inode);
4724
4725         if (IS_SYNC(inode))
4726                 ext4_handle_sync(handle);
4727
4728         up_write(&EXT4_I(inode)->i_data_sem);
4729
4730 out:
4731         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4732         ext4_mark_inode_dirty(handle, inode);
4733         ext4_journal_stop(handle);
4734 out_dio:
4735         ext4_inode_resume_unlocked_dio(inode);
4736 out_mutex:
4737         mutex_unlock(&inode->i_mutex);
4738         return err;
4739 }
4740
4741 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4742                 __u64 start, __u64 len)
4743 {
4744         ext4_lblk_t start_blk;
4745         int error = 0;
4746
4747         if (ext4_has_inline_data(inode)) {
4748                 int has_inline = 1;
4749
4750                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline);
4751
4752                 if (has_inline)
4753                         return error;
4754         }
4755
4756         /* fallback to generic here if not in extents fmt */
4757         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4758                 return generic_block_fiemap(inode, fieinfo, start, len,
4759                         ext4_get_block);
4760
4761         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
4762                 return -EBADR;
4763
4764         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4765                 error = ext4_xattr_fiemap(inode, fieinfo);
4766         } else {
4767                 ext4_lblk_t len_blks;
4768                 __u64 last_blk;
4769
4770                 start_blk = start >> inode->i_sb->s_blocksize_bits;
4771                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
4772                 if (last_blk >= EXT_MAX_BLOCKS)
4773                         last_blk = EXT_MAX_BLOCKS-1;
4774                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
4775
4776                 /*
4777                  * Walk the extent tree gathering extent information
4778                  * and pushing extents back to the user.
4779                  */
4780                 error = ext4_fill_fiemap_extents(inode, start_blk,
4781                                                  len_blks, fieinfo);
4782         }
4783
4784         return error;
4785 }