fs/ext4/extents.c

   1 /*
   2  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3  * Written by Alex Tomas <alex@clusterfs.com>
   4  *
   5  * Architecture independence:
   6  *   Copyright (c) 2005, Bull S.A.
   7  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21  */
  22
  23 /*
  24  * Extents support for EXT4
  25  *
  26  * TODO:
  27  *   - ext4*_error() should be used in some situations
  28  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29  *   - smart tree reduction
  30  */
  31
  32 #include <linux/fs.h>
  33 #include <linux/time.h>
  34 #include <linux/jbd2.h>
  35 #include <linux/highuid.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/quotaops.h>
  38 #include <linux/string.h>
  39 #include <linux/slab.h>
  40 #include <linux/uaccess.h>
  41 #include <linux/fiemap.h>
  42 #include <linux/backing-dev.h>
  43 #include "ext4_jbd2.h"
  44 #include "ext4_extents.h"
  45 #include "xattr.h"
  46
  47 #include <trace/events/ext4.h>
  48
  49 /*
  50  * used by extent splitting.
  51  */
  52 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  53                                         due to ENOSPC */
  54 #define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  55 #define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  56
  57 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  58 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  59
  60 static __le32 ext4_extent_block_csum(struct inode *inode,
  61                                      struct ext4_extent_header *eh)
  62 {
  63         struct ext4_inode_info *ei = EXT4_I(inode);
  64         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  65         __u32 csum;
  66
  67         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  68                            EXT4_EXTENT_TAIL_OFFSET(eh));
  69         return cpu_to_le32(csum);
  70 }
  71
  72 static int ext4_extent_block_csum_verify(struct inode *inode,
  73                                          struct ext4_extent_header *eh)
  74 {
  75         struct ext4_extent_tail *et;
  76
  77         if (!ext4_has_metadata_csum(inode->i_sb))
  78                 return 1;
  79
  80         et = find_ext4_extent_tail(eh);
  81         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  82                 return 0;
  83         return 1;
  84 }
  85
  86 static void ext4_extent_block_csum_set(struct inode *inode,
  87                                        struct ext4_extent_header *eh)
  88 {
  89         struct ext4_extent_tail *et;
  90
  91         if (!ext4_has_metadata_csum(inode->i_sb))
  92                 return;
  93
  94         et = find_ext4_extent_tail(eh);
  95         et->et_checksum = ext4_extent_block_csum(inode, eh);
  96 }
  97
  98 static int ext4_split_extent(handle_t *handle,
  99                                 struct inode *inode,
 100                                 struct ext4_ext_path **ppath,
 101                                 struct ext4_map_blocks *map,
 102                                 int split_flag,
 103                                 int flags);
 104
 105 static int ext4_split_extent_at(handle_t *handle,
 106                              struct inode *inode,
 107                              struct ext4_ext_path **ppath,
 108                              ext4_lblk_t split,
 109                              int split_flag,
 110                              int flags);
 111
 112 static int ext4_find_delayed_extent(struct inode *inode,
 113                                     struct extent_status *newes);
 114
 115 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 116                                             struct inode *inode,
 117                                             int needed)
 118 {
 119         int err;
 120
 121         if (!ext4_handle_valid(handle))
 122                 return 0;
 123         if (handle->h_buffer_credits >= needed)
 124                 return 0;
 125         /*
 126          * If we need to extend the journal get a few extra blocks
 127          * while we're at it for efficiency's sake.
 128          */
 129         needed += 3;
 130         err = ext4_journal_extend(handle, needed - handle->h_buffer_credits);
 131         if (err <= 0)
 132                 return err;
 133         err = ext4_truncate_restart_trans(handle, inode, needed);
 134         if (err == 0)
 135                 err = -EAGAIN;
 136
 137         return err;
 138 }
 139
 140 /*
 141  * could return:
 142  *  - EROFS
 143  *  - ENOMEM
 144  */
 145 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 146                                 struct ext4_ext_path *path)
 147 {
 148         if (path->p_bh) {
 149                 /* path points to block */
 150                 BUFFER_TRACE(path->p_bh, "get_write_access");
 151                 return ext4_journal_get_write_access(handle, path->p_bh);
 152         }
 153         /* path points to leaf/index in inode body */
 154         /* we use in-core data, no need to protect them */
 155         return 0;
 156 }
 157
 158 /*
 159  * could return:
 160  *  - EROFS
 161  *  - ENOMEM
 162  *  - EIO
 163  */
 164 int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 165                      struct inode *inode, struct ext4_ext_path *path)
 166 {
 167         int err;
 168
 169         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 170         if (path->p_bh) {
 171                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 172                 /* path points to block */
 173                 err = __ext4_handle_dirty_metadata(where, line, handle,
 174                                                    inode, path->p_bh);
 175         } else {
 176                 /* path points to leaf/index in inode body */
 177                 err = ext4_mark_inode_dirty(handle, inode);
 178         }
 179         return err;
 180 }
 181
 182 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 183                               struct ext4_ext_path *path,
 184                               ext4_lblk_t block)
 185 {
 186         if (path) {
 187                 int depth = path->p_depth;
 188                 struct ext4_extent *ex;
 189
 190                 /*
 191                  * Try to predict block placement assuming that we are
 192                  * filling in a file which will eventually be
 193                  * non-sparse --- i.e., in the case of libbfd writing
 194                  * an ELF object sections out-of-order but in a way
 195                  * the eventually results in a contiguous object or
 196                  * executable file, or some database extending a table
 197                  * space file.  However, this is actually somewhat
 198                  * non-ideal if we are writing a sparse file such as
 199                  * qemu or KVM writing a raw image file that is going
 200                  * to stay fairly sparse, since it will end up
 201                  * fragmenting the file system's free space.  Maybe we
 202                  * should have some hueristics or some way to allow
 203                  * userspace to pass a hint to file system,
 204                  * especially if the latter case turns out to be
 205                  * common.
 206                  */
 207                 ex = path[depth].p_ext;
 208                 if (ex) {
 209                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 210                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 211
 212                         if (block > ext_block)
 213                                 return ext_pblk + (block - ext_block);
 214                         else
 215                                 return ext_pblk - (ext_block - block);
 216                 }
 217
 218                 /* it looks like index is empty;
 219                  * try to find starting block from index itself */
 220                 if (path[depth].p_bh)
 221                         return path[depth].p_bh->b_blocknr;
 222         }
 223
 224         /* OK. use inode's group */
 225         return ext4_inode_to_goal_block(inode);
 226 }
 227
 228 /*
 229  * Allocation for a meta data block
 230  */
 231 static ext4_fsblk_t
 232 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 233                         struct ext4_ext_path *path,
 234                         struct ext4_extent *ex, int *err, unsigned int flags)
 235 {
 236         ext4_fsblk_t goal, newblock;
 237
 238         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 239         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 240                                         NULL, err);
 241         return newblock;
 242 }
 243
 244 static inline int ext4_ext_space_block(struct inode *inode, int check)
 245 {
 246         int size;
 247
 248         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 249                         / sizeof(struct ext4_extent);
 250 #ifdef AGGRESSIVE_TEST
 251         if (!check && size > 6)
 252                 size = 6;
 253 #endif
 254         return size;
 255 }
 256
 257 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 258 {
 259         int size;
 260
 261         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 262                         / sizeof(struct ext4_extent_idx);
 263 #ifdef AGGRESSIVE_TEST
 264         if (!check && size > 5)
 265                 size = 5;
 266 #endif
 267         return size;
 268 }
 269
 270 static inline int ext4_ext_space_root(struct inode *inode, int check)
 271 {
 272         int size;
 273
 274         size = sizeof(EXT4_I(inode)->i_data);
 275         size -= sizeof(struct ext4_extent_header);
 276         size /= sizeof(struct ext4_extent);
 277 #ifdef AGGRESSIVE_TEST
 278         if (!check && size > 3)
 279                 size = 3;
 280 #endif
 281         return size;
 282 }
 283
 284 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 285 {
 286         int size;
 287
 288         size = sizeof(EXT4_I(inode)->i_data);
 289         size -= sizeof(struct ext4_extent_header);
 290         size /= sizeof(struct ext4_extent_idx);
 291 #ifdef AGGRESSIVE_TEST
 292         if (!check && size > 4)
 293                 size = 4;
 294 #endif
 295         return size;
 296 }
 297
 298 static inline int
 299 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 300                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 301                            int nofail)
 302 {
 303         struct ext4_ext_path *path = *ppath;
 304         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 305
 306         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 307                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 308                         EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
 309                         (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
 310 }
 311
 312 /*
 313  * Calculate the number of metadata blocks needed
 314  * to allocate @blocks
 315  * Worse case is one block per extent
 316  */
 317 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 318 {
 319         struct ext4_inode_info *ei = EXT4_I(inode);
 320         int idxs;
 321
 322         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 323                 / sizeof(struct ext4_extent_idx));
 324
 325         /*
 326          * If the new delayed allocation block is contiguous with the
 327          * previous da block, it can share index blocks with the
 328          * previous block, so we only need to allocate a new index
 329          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 330          * an additional index block, and at ldxs**3 blocks, yet
 331          * another index blocks.
 332          */
 333         if (ei->i_da_metadata_calc_len &&
 334             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 335                 int num = 0;
 336
 337                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 338                         num++;
 339                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 340                         num++;
 341                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 342                         num++;
 343                         ei->i_da_metadata_calc_len = 0;
 344                 } else
 345                         ei->i_da_metadata_calc_len++;
 346                 ei->i_da_metadata_calc_last_lblock++;
 347                 return num;
 348         }
 349
 350         /*
 351          * In the worst case we need a new set of index blocks at
 352          * every level of the inode's extent tree.
 353          */
 354         ei->i_da_metadata_calc_len = 1;
 355         ei->i_da_metadata_calc_last_lblock = lblock;
 356         return ext_depth(inode) + 1;
 357 }
 358
 359 static int
 360 ext4_ext_max_entries(struct inode *inode, int depth)
 361 {
 362         int max;
 363
 364         if (depth == ext_depth(inode)) {
 365                 if (depth == 0)
 366                         max = ext4_ext_space_root(inode, 1);
 367                 else
 368                         max = ext4_ext_space_root_idx(inode, 1);
 369         } else {
 370                 if (depth == 0)
 371                         max = ext4_ext_space_block(inode, 1);
 372                 else
 373                         max = ext4_ext_space_block_idx(inode, 1);
 374         }
 375
 376         return max;
 377 }
 378
 379 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 380 {
 381         ext4_fsblk_t block = ext4_ext_pblock(ext);
 382         int len = ext4_ext_get_actual_len(ext);
 383         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 384
 385         /*
 386          * We allow neither:
 387          *  - zero length
 388          *  - overflow/wrap-around
 389          */
 390         if (lblock + len <= lblock)
 391                 return 0;
 392         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 393 }
 394
 395 static int ext4_valid_extent_idx(struct inode *inode,
 396                                 struct ext4_extent_idx *ext_idx)
 397 {
 398         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 399
 400         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 401 }
 402
 403 static int ext4_valid_extent_entries(struct inode *inode,
 404                                 struct ext4_extent_header *eh,
 405                                 int depth)
 406 {
 407         unsigned short entries;
 408         if (eh->eh_entries == 0)
 409                 return 1;
 410
 411         entries = le16_to_cpu(eh->eh_entries);
 412
 413         if (depth == 0) {
 414                 /* leaf entries */
 415                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 416                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 417                 ext4_fsblk_t pblock = 0;
 418                 ext4_lblk_t lblock = 0;
 419                 ext4_lblk_t prev = 0;
 420                 int len = 0;
 421                 while (entries) {
 422                         if (!ext4_valid_extent(inode, ext))
 423                                 return 0;
 424
 425                         /* Check for overlapping extents */
 426                         lblock = le32_to_cpu(ext->ee_block);
 427                         len = ext4_ext_get_actual_len(ext);
 428                         if ((lblock <= prev) && prev) {
 429                                 pblock = ext4_ext_pblock(ext);
 430                                 es->s_last_error_block = cpu_to_le64(pblock);
 431                                 return 0;
 432                         }
 433                         ext++;
 434                         entries--;
 435                         prev = lblock + len - 1;
 436                 }
 437         } else {
 438                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 439                 while (entries) {
 440                         if (!ext4_valid_extent_idx(inode, ext_idx))
 441                                 return 0;
 442                         ext_idx++;
 443                         entries--;
 444                 }
 445         }
 446         return 1;
 447 }
 448
 449 static int __ext4_ext_check(const char *function, unsigned int line,
 450                             struct inode *inode, struct ext4_extent_header *eh,
 451                             int depth, ext4_fsblk_t pblk)
 452 {
 453         const char *error_msg;
 454         int max = 0, err = -EFSCORRUPTED;
 455
 456         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 457                 error_msg = "invalid magic";
 458                 goto corrupted;
 459         }
 460         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 461                 error_msg = "unexpected eh_depth";
 462                 goto corrupted;
 463         }
 464         if (unlikely(eh->eh_max == 0)) {
 465                 error_msg = "invalid eh_max";
 466                 goto corrupted;
 467         }
 468         max = ext4_ext_max_entries(inode, depth);
 469         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 470                 error_msg = "too large eh_max";
 471                 goto corrupted;
 472         }
 473         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 474                 error_msg = "invalid eh_entries";
 475                 goto corrupted;
 476         }
 477         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 478                 error_msg = "invalid extent entries";
 479                 goto corrupted;
 480         }
 481         if (unlikely(depth > 32)) {
 482                 error_msg = "too large eh_depth";
 483                 goto corrupted;
 484         }
 485         /* Verify checksum on non-root extent tree nodes */
 486         if (ext_depth(inode) != depth &&
 487             !ext4_extent_block_csum_verify(inode, eh)) {
 488                 error_msg = "extent tree corrupted";
 489                 err = -EFSBADCRC;
 490                 goto corrupted;
 491         }
 492         return 0;
 493
 494 corrupted:
 495         ext4_error_inode(inode, function, line, 0,
 496                          "pblk %llu bad header/extent: %s - magic %x, "
 497                          "entries %u, max %u(%u), depth %u(%u)",
 498                          (unsigned long long) pblk, error_msg,
 499                          le16_to_cpu(eh->eh_magic),
 500                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 501                          max, le16_to_cpu(eh->eh_depth), depth);
 502         return err;
 503 }
 504
 505 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 506         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 507
 508 int ext4_ext_check_inode(struct inode *inode)
 509 {
 510         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 511 }
 512
 513 static struct buffer_head *
 514 __read_extent_tree_block(const char *function, unsigned int line,
 515                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 516                          int flags)
 517 {
 518         struct buffer_head              *bh;
 519         int                             err;
 520
 521         bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
 522         if (unlikely(!bh))
 523                 return ERR_PTR(-ENOMEM);
 524
 525         if (!bh_uptodate_or_lock(bh)) {
 526                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 527                 err = bh_submit_read(bh);
 528                 if (err < 0)
 529                         goto errout;
 530         }
 531         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 532                 return bh;
 533         err = __ext4_ext_check(function, line, inode,
 534                                ext_block_hdr(bh), depth, pblk);
 535         if (err)
 536                 goto errout;
 537         set_buffer_verified(bh);
 538         /*
 539          * If this is a leaf block, cache all of its entries
 540          */
 541         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 542                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 543                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 544                 ext4_lblk_t prev = 0;
 545                 int i;
 546
 547                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 548                         unsigned int status = EXTENT_STATUS_WRITTEN;
 549                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 550                         int len = ext4_ext_get_actual_len(ex);
 551
 552                         if (prev && (prev != lblk))
 553                                 ext4_es_cache_extent(inode, prev,
 554                                                      lblk - prev, ~0,
 555                                                      EXTENT_STATUS_HOLE);
 556
 557                         if (ext4_ext_is_unwritten(ex))
 558                                 status = EXTENT_STATUS_UNWRITTEN;
 559                         ext4_es_cache_extent(inode, lblk, len,
 560                                              ext4_ext_pblock(ex), status);
 561                         prev = lblk + len;
 562                 }
 563         }
 564         return bh;
 565 errout:
 566         put_bh(bh);
 567         return ERR_PTR(err);
 568
 569 }
 570
 571 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 572         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 573                                  (depth), (flags))
 574
 575 /*
 576  * This function is called to cache a file's extent information in the
 577  * extent status tree
 578  */
 579 int ext4_ext_precache(struct inode *inode)
 580 {
 581         struct ext4_inode_info *ei = EXT4_I(inode);
 582         struct ext4_ext_path *path = NULL;
 583         struct buffer_head *bh;
 584         int i = 0, depth, ret = 0;
 585
 586         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 587                 return 0;       /* not an extent-mapped inode */
 588
 589         down_read(&ei->i_data_sem);
 590         depth = ext_depth(inode);
 591
 592         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 593                        GFP_NOFS);
 594         if (path == NULL) {
 595                 up_read(&ei->i_data_sem);
 596                 return -ENOMEM;
 597         }
 598
 599         /* Don't cache anything if there are no external extent blocks */
 600         if (depth == 0)
 601                 goto out;
 602         path[0].p_hdr = ext_inode_hdr(inode);
 603         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 604         if (ret)
 605                 goto out;
 606         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 607         while (i >= 0) {
 608                 /*
 609                  * If this is a leaf block or we've reached the end of
 610                  * the index block, go up
 611                  */
 612                 if ((i == depth) ||
 613                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 614                         brelse(path[i].p_bh);
 615                         path[i].p_bh = NULL;
 616                         i--;
 617                         continue;
 618                 }
 619                 bh = read_extent_tree_block(inode,
 620                                             ext4_idx_pblock(path[i].p_idx++),
 621                                             depth - i - 1,
 622                                             EXT4_EX_FORCE_CACHE);
 623                 if (IS_ERR(bh)) {
 624                         ret = PTR_ERR(bh);
 625                         break;
 626                 }
 627                 i++;
 628                 path[i].p_bh = bh;
 629                 path[i].p_hdr = ext_block_hdr(bh);
 630                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 631         }
 632         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 633 out:
 634         up_read(&ei->i_data_sem);
 635         ext4_ext_drop_refs(path);
 636         kfree(path);
 637         return ret;
 638 }
 639
 640 #ifdef EXT_DEBUG
 641 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 642 {
 643         int k, l = path->p_depth;
 644
 645         ext_debug("path:");
 646         for (k = 0; k <= l; k++, path++) {
 647                 if (path->p_idx) {
 648                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 649                             ext4_idx_pblock(path->p_idx));
 650                 } else if (path->p_ext) {
 651                         ext_debug("  %d:[%d]%d:%llu ",
 652                                   le32_to_cpu(path->p_ext->ee_block),
 653                                   ext4_ext_is_unwritten(path->p_ext),
 654                                   ext4_ext_get_actual_len(path->p_ext),
 655                                   ext4_ext_pblock(path->p_ext));
 656                 } else
 657                         ext_debug("  []");
 658         }
 659         ext_debug("\n");
 660 }
 661
 662 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 663 {
 664         int depth = ext_depth(inode);
 665         struct ext4_extent_header *eh;
 666         struct ext4_extent *ex;
 667         int i;
 668
 669         if (!path)
 670                 return;
 671
 672         eh = path[depth].p_hdr;
 673         ex = EXT_FIRST_EXTENT(eh);
 674
 675         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 676
 677         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 678                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 679                           ext4_ext_is_unwritten(ex),
 680                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 681         }
 682         ext_debug("\n");
 683 }
 684
 685 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 686                         ext4_fsblk_t newblock, int level)
 687 {
 688         int depth = ext_depth(inode);
 689         struct ext4_extent *ex;
 690
 691         if (depth != level) {
 692                 struct ext4_extent_idx *idx;
 693                 idx = path[level].p_idx;
 694                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 695                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 696                                         le32_to_cpu(idx->ei_block),
 697                                         ext4_idx_pblock(idx),
 698                                         newblock);
 699                         idx++;
 700                 }
 701
 702                 return;
 703         }
 704
 705         ex = path[depth].p_ext;
 706         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 707                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 708                                 le32_to_cpu(ex->ee_block),
 709                                 ext4_ext_pblock(ex),
 710                                 ext4_ext_is_unwritten(ex),
 711                                 ext4_ext_get_actual_len(ex),
 712                                 newblock);
 713                 ex++;
 714         }
 715 }
 716
 717 #else
 718 #define ext4_ext_show_path(inode, path)
 719 #define ext4_ext_show_leaf(inode, path)
 720 #define ext4_ext_show_move(inode, path, newblock, level)
 721 #endif
 722
 723 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 724 {
 725         int depth, i;
 726
 727         if (!path)
 728                 return;
 729         depth = path->p_depth;
 730         for (i = 0; i <= depth; i++, path++)
 731                 if (path->p_bh) {
 732                         brelse(path->p_bh);
 733                         path->p_bh = NULL;
 734                 }
 735 }
 736
 737 /*
 738  * ext4_ext_binsearch_idx:
 739  * binary search for the closest index of the given block
 740  * the header must be checked before calling this
 741  */
 742 static void
 743 ext4_ext_binsearch_idx(struct inode *inode,
 744                         struct ext4_ext_path *path, ext4_lblk_t block)
 745 {
 746         struct ext4_extent_header *eh = path->p_hdr;
 747         struct ext4_extent_idx *r, *l, *m;
 748
 749
 750         ext_debug("binsearch for %u(idx):  ", block);
 751
 752         l = EXT_FIRST_INDEX(eh) + 1;
 753         r = EXT_LAST_INDEX(eh);
 754         while (l <= r) {
 755                 m = l + (r - l) / 2;
 756                 if (block < le32_to_cpu(m->ei_block))
 757                         r = m - 1;
 758                 else
 759                         l = m + 1;
 760                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 761                                 m, le32_to_cpu(m->ei_block),
 762                                 r, le32_to_cpu(r->ei_block));
 763         }
 764
 765         path->p_idx = l - 1;
 766         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 767                   ext4_idx_pblock(path->p_idx));
 768
 769 #ifdef CHECK_BINSEARCH
 770         {
 771                 struct ext4_extent_idx *chix, *ix;
 772                 int k;
 773
 774                 chix = ix = EXT_FIRST_INDEX(eh);
 775                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 776                   if (k != 0 &&
 777                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 778                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 779                                        "first=0x%p\n", k,
 780                                        ix, EXT_FIRST_INDEX(eh));
 781                                 printk(KERN_DEBUG "%u <= %u\n",
 782                                        le32_to_cpu(ix->ei_block),
 783                                        le32_to_cpu(ix[-1].ei_block));
 784                         }
 785                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 786                                            <= le32_to_cpu(ix[-1].ei_block));
 787                         if (block < le32_to_cpu(ix->ei_block))
 788                                 break;
 789                         chix = ix;
 790                 }
 791                 BUG_ON(chix != path->p_idx);
 792         }
 793 #endif
 794
 795 }
 796
 797 /*
 798  * ext4_ext_binsearch:
 799  * binary search for closest extent of the given block
 800  * the header must be checked before calling this
 801  */
 802 static void
 803 ext4_ext_binsearch(struct inode *inode,
 804                 struct ext4_ext_path *path, ext4_lblk_t block)
 805 {
 806         struct ext4_extent_header *eh = path->p_hdr;
 807         struct ext4_extent *r, *l, *m;
 808
 809         if (eh->eh_entries == 0) {
 810                 /*
 811                  * this leaf is empty:
 812                  * we get such a leaf in split/add case
 813                  */
 814                 return;
 815         }
 816
 817         ext_debug("binsearch for %u:  ", block);
 818
 819         l = EXT_FIRST_EXTENT(eh) + 1;
 820         r = EXT_LAST_EXTENT(eh);
 821
 822         while (l <= r) {
 823                 m = l + (r - l) / 2;
 824                 if (block < le32_to_cpu(m->ee_block))
 825                         r = m - 1;
 826                 else
 827                         l = m + 1;
 828                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 829                                 m, le32_to_cpu(m->ee_block),
 830                                 r, le32_to_cpu(r->ee_block));
 831         }
 832
 833         path->p_ext = l - 1;
 834         ext_debug("  -> %d:%llu:[%d]%d ",
 835                         le32_to_cpu(path->p_ext->ee_block),
 836                         ext4_ext_pblock(path->p_ext),
 837                         ext4_ext_is_unwritten(path->p_ext),
 838                         ext4_ext_get_actual_len(path->p_ext));
 839
 840 #ifdef CHECK_BINSEARCH
 841         {
 842                 struct ext4_extent *chex, *ex;
 843                 int k;
 844
 845                 chex = ex = EXT_FIRST_EXTENT(eh);
 846                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 847                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 848                                           <= le32_to_cpu(ex[-1].ee_block));
 849                         if (block < le32_to_cpu(ex->ee_block))
 850                                 break;
 851                         chex = ex;
 852                 }
 853                 BUG_ON(chex != path->p_ext);
 854         }
 855 #endif
 856
 857 }
 858
 859 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 860 {
 861         struct ext4_extent_header *eh;
 862
 863         eh = ext_inode_hdr(inode);
 864         eh->eh_depth = 0;
 865         eh->eh_entries = 0;
 866         eh->eh_magic = EXT4_EXT_MAGIC;
 867         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 868         ext4_mark_inode_dirty(handle, inode);
 869         return 0;
 870 }
 871
 872 struct ext4_ext_path *
 873 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 874                  struct ext4_ext_path **orig_path, int flags)
 875 {
 876         struct ext4_extent_header *eh;
 877         struct buffer_head *bh;
 878         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 879         short int depth, i, ppos = 0;
 880         int ret;
 881
 882         eh = ext_inode_hdr(inode);
 883         depth = ext_depth(inode);
 884
 885         if (path) {
 886                 ext4_ext_drop_refs(path);
 887                 if (depth > path[0].p_maxdepth) {
 888                         kfree(path);
 889                         *orig_path = path = NULL;
 890                 }
 891         }
 892         if (!path) {
 893                 /* account possible depth increase */
 894                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 895                                 GFP_NOFS);
 896                 if (unlikely(!path))
 897                         return ERR_PTR(-ENOMEM);
 898                 path[0].p_maxdepth = depth + 1;
 899         }
 900         path[0].p_hdr = eh;
 901         path[0].p_bh = NULL;
 902
 903         i = depth;
 904         /* walk through the tree */
 905         while (i) {
 906                 ext_debug("depth %d: num %d, max %d\n",
 907                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 908
 909                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 910                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 911                 path[ppos].p_depth = i;
 912                 path[ppos].p_ext = NULL;
 913
 914                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 915                                             flags);
 916                 if (IS_ERR(bh)) {
 917                         ret = PTR_ERR(bh);
 918                         goto err;
 919                 }
 920
 921                 eh = ext_block_hdr(bh);
 922                 ppos++;
 923                 path[ppos].p_bh = bh;
 924                 path[ppos].p_hdr = eh;
 925         }
 926
 927         path[ppos].p_depth = i;
 928         path[ppos].p_ext = NULL;
 929         path[ppos].p_idx = NULL;
 930
 931         /* find extent */
 932         ext4_ext_binsearch(inode, path + ppos, block);
 933         /* if not an empty leaf */
 934         if (path[ppos].p_ext)
 935                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 936
 937         ext4_ext_show_path(inode, path);
 938
 939         return path;
 940
 941 err:
 942         ext4_ext_drop_refs(path);
 943         kfree(path);
 944         if (orig_path)
 945                 *orig_path = NULL;
 946         return ERR_PTR(ret);
 947 }
 948
 949 /*
 950  * ext4_ext_insert_index:
 951  * insert new index [@logical;@ptr] into the block at @curp;
 952  * check where to insert: before @curp or after @curp
 953  */
 954 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 955                                  struct ext4_ext_path *curp,
 956                                  int logical, ext4_fsblk_t ptr)
 957 {
 958         struct ext4_extent_idx *ix;
 959         int len, err;
 960
 961         err = ext4_ext_get_access(handle, inode, curp);
 962         if (err)
 963                 return err;
 964
 965         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 966                 EXT4_ERROR_INODE(inode,
 967                                  "logical %d == ei_block %d!",
 968                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 969                 return -EFSCORRUPTED;
 970         }
 971
 972         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 973                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 974                 EXT4_ERROR_INODE(inode,
 975                                  "eh_entries %d >= eh_max %d!",
 976                                  le16_to_cpu(curp->p_hdr->eh_entries),
 977                                  le16_to_cpu(curp->p_hdr->eh_max));
 978                 return -EFSCORRUPTED;
 979         }
 980
 981         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 982                 /* insert after */
 983                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 984                 ix = curp->p_idx + 1;
 985         } else {
 986                 /* insert before */
 987                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 988                 ix = curp->p_idx;
 989         }
 990
 991         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 992         BUG_ON(len < 0);
 993         if (len > 0) {
 994                 ext_debug("insert new index %d: "
 995                                 "move %d indices from 0x%p to 0x%p\n",
 996                                 logical, len, ix, ix + 1);
 997                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 998         }
 999
1000         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
1001                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1002                 return -EFSCORRUPTED;
1003         }
1004
1005         ix->ei_block = cpu_to_le32(logical);
1006         ext4_idx_store_pblock(ix, ptr);
1007         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1008
1009         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1010                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1011                 return -EFSCORRUPTED;
1012         }
1013
1014         err = ext4_ext_dirty(handle, inode, curp);
1015         ext4_std_error(inode->i_sb, err);
1016
1017         return err;
1018 }
1019
1020 /*
1021  * ext4_ext_split:
1022  * inserts new subtree into the path, using free index entry
1023  * at depth @at:
1024  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1025  * - makes decision where to split
1026  * - moves remaining extents and index entries (right to the split point)
1027  *   into the newly allocated blocks
1028  * - initializes subtree
1029  */
1030 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1031                           unsigned int flags,
1032                           struct ext4_ext_path *path,
1033                           struct ext4_extent *newext, int at)
1034 {
1035         struct buffer_head *bh = NULL;
1036         int depth = ext_depth(inode);
1037         struct ext4_extent_header *neh;
1038         struct ext4_extent_idx *fidx;
1039         int i = at, k, m, a;
1040         ext4_fsblk_t newblock, oldblock;
1041         __le32 border;
1042         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1043         int err = 0;
1044
1045         /* make decision: where to split? */
1046         /* FIXME: now decision is simplest: at current extent */
1047
1048         /* if current leaf will be split, then we should use
1049          * border from split point */
1050         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1051                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1052                 return -EFSCORRUPTED;
1053         }
1054         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1055                 border = path[depth].p_ext[1].ee_block;
1056                 ext_debug("leaf will be split."
1057                                 " next leaf starts at %d\n",
1058                                   le32_to_cpu(border));
1059         } else {
1060                 border = newext->ee_block;
1061                 ext_debug("leaf will be added."
1062                                 " next leaf starts at %d\n",
1063                                 le32_to_cpu(border));
1064         }
1065
1066         /*
1067          * If error occurs, then we break processing
1068          * and mark filesystem read-only. index won't
1069          * be inserted and tree will be in consistent
1070          * state. Next mount will repair buffers too.
1071          */
1072
1073         /*
1074          * Get array to track all allocated blocks.
1075          * We need this to handle errors and free blocks
1076          * upon them.
1077          */
1078         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1079         if (!ablocks)
1080                 return -ENOMEM;
1081
1082         /* allocate all needed blocks */
1083         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1084         for (a = 0; a < depth - at; a++) {
1085                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1086                                                    newext, &err, flags);
1087                 if (newblock == 0)
1088                         goto cleanup;
1089                 ablocks[a] = newblock;
1090         }
1091
1092         /* initialize new leaf */
1093         newblock = ablocks[--a];
1094         if (unlikely(newblock == 0)) {
1095                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1096                 err = -EFSCORRUPTED;
1097                 goto cleanup;
1098         }
1099         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1100         if (unlikely(!bh)) {
1101                 err = -ENOMEM;
1102                 goto cleanup;
1103         }
1104         lock_buffer(bh);
1105
1106         err = ext4_journal_get_create_access(handle, bh);
1107         if (err)
1108                 goto cleanup;
1109
1110         neh = ext_block_hdr(bh);
1111         neh->eh_entries = 0;
1112         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1113         neh->eh_magic = EXT4_EXT_MAGIC;
1114         neh->eh_depth = 0;
1115
1116         /* move remainder of path[depth] to the new leaf */
1117         if (unlikely(path[depth].p_hdr->eh_entries !=
1118                      path[depth].p_hdr->eh_max)) {
1119                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1120                                  path[depth].p_hdr->eh_entries,
1121                                  path[depth].p_hdr->eh_max);
1122                 err = -EFSCORRUPTED;
1123                 goto cleanup;
1124         }
1125         /* start copy from next extent */
1126         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1127         ext4_ext_show_move(inode, path, newblock, depth);
1128         if (m) {
1129                 struct ext4_extent *ex;
1130                 ex = EXT_FIRST_EXTENT(neh);
1131                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1132                 le16_add_cpu(&neh->eh_entries, m);
1133         }
1134
1135         ext4_extent_block_csum_set(inode, neh);
1136         set_buffer_uptodate(bh);
1137         unlock_buffer(bh);
1138
1139         err = ext4_handle_dirty_metadata(handle, inode, bh);
1140         if (err)
1141                 goto cleanup;
1142         brelse(bh);
1143         bh = NULL;
1144
1145         /* correct old leaf */
1146         if (m) {
1147                 err = ext4_ext_get_access(handle, inode, path + depth);
1148                 if (err)
1149                         goto cleanup;
1150                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1151                 err = ext4_ext_dirty(handle, inode, path + depth);
1152                 if (err)
1153                         goto cleanup;
1154
1155         }
1156
1157         /* create intermediate indexes */
1158         k = depth - at - 1;
1159         if (unlikely(k < 0)) {
1160                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1161                 err = -EFSCORRUPTED;
1162                 goto cleanup;
1163         }
1164         if (k)
1165                 ext_debug("create %d intermediate indices\n", k);
1166         /* insert new index into current index block */
1167         /* current depth stored in i var */
1168         i = depth - 1;
1169         while (k--) {
1170                 oldblock = newblock;
1171                 newblock = ablocks[--a];
1172                 bh = sb_getblk(inode->i_sb, newblock);
1173                 if (unlikely(!bh)) {
1174                         err = -ENOMEM;
1175                         goto cleanup;
1176                 }
1177                 lock_buffer(bh);
1178
1179                 err = ext4_journal_get_create_access(handle, bh);
1180                 if (err)
1181                         goto cleanup;
1182
1183                 neh = ext_block_hdr(bh);
1184                 neh->eh_entries = cpu_to_le16(1);
1185                 neh->eh_magic = EXT4_EXT_MAGIC;
1186                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1187                 neh->eh_depth = cpu_to_le16(depth - i);
1188                 fidx = EXT_FIRST_INDEX(neh);
1189                 fidx->ei_block = border;
1190                 ext4_idx_store_pblock(fidx, oldblock);
1191
1192                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1193                                 i, newblock, le32_to_cpu(border), oldblock);
1194
1195                 /* move remainder of path[i] to the new index block */
1196                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1197                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1198                         EXT4_ERROR_INODE(inode,
1199                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1200                                          le32_to_cpu(path[i].p_ext->ee_block));
1201                         err = -EFSCORRUPTED;
1202                         goto cleanup;
1203                 }
1204                 /* start copy indexes */
1205                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1206                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1207                                 EXT_MAX_INDEX(path[i].p_hdr));
1208                 ext4_ext_show_move(inode, path, newblock, i);
1209                 if (m) {
1210                         memmove(++fidx, path[i].p_idx,
1211                                 sizeof(struct ext4_extent_idx) * m);
1212                         le16_add_cpu(&neh->eh_entries, m);
1213                 }
1214                 ext4_extent_block_csum_set(inode, neh);
1215                 set_buffer_uptodate(bh);
1216                 unlock_buffer(bh);
1217
1218                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1219                 if (err)
1220                         goto cleanup;
1221                 brelse(bh);
1222                 bh = NULL;
1223
1224                 /* correct old index */
1225                 if (m) {
1226                         err = ext4_ext_get_access(handle, inode, path + i);
1227                         if (err)
1228                                 goto cleanup;
1229                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1230                         err = ext4_ext_dirty(handle, inode, path + i);
1231                         if (err)
1232                                 goto cleanup;
1233                 }
1234
1235                 i--;
1236         }
1237
1238         /* insert new index */
1239         err = ext4_ext_insert_index(handle, inode, path + at,
1240                                     le32_to_cpu(border), newblock);
1241
1242 cleanup:
1243         if (bh) {
1244                 if (buffer_locked(bh))
1245                         unlock_buffer(bh);
1246                 brelse(bh);
1247         }
1248
1249         if (err) {
1250                 /* free all allocated blocks in error case */
1251                 for (i = 0; i < depth; i++) {
1252                         if (!ablocks[i])
1253                                 continue;
1254                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1255                                          EXT4_FREE_BLOCKS_METADATA);
1256                 }
1257         }
1258         kfree(ablocks);
1259
1260         return err;
1261 }
1262
1263 /*
1264  * ext4_ext_grow_indepth:
1265  * implements tree growing procedure:
1266  * - allocates new block
1267  * - moves top-level data (index block or leaf) into the new block
1268  * - initializes new top-level, creating index that points to the
1269  *   just created block
1270  */
1271 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1272                                  unsigned int flags)
1273 {
1274         struct ext4_extent_header *neh;
1275         struct buffer_head *bh;
1276         ext4_fsblk_t newblock, goal = 0;
1277         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1278         int err = 0;
1279
1280         /* Try to prepend new index to old one */
1281         if (ext_depth(inode))
1282                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1283         if (goal > le32_to_cpu(es->s_first_data_block)) {
1284                 flags |= EXT4_MB_HINT_TRY_GOAL;
1285                 goal--;
1286         } else
1287                 goal = ext4_inode_to_goal_block(inode);
1288         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1289                                         NULL, &err);
1290         if (newblock == 0)
1291                 return err;
1292
1293         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1294         if (unlikely(!bh))
1295                 return -ENOMEM;
1296         lock_buffer(bh);
1297
1298         err = ext4_journal_get_create_access(handle, bh);
1299         if (err) {
1300                 unlock_buffer(bh);
1301                 goto out;
1302         }
1303
1304         /* move top-level index/leaf into new block */
1305         memmove(bh->b_data, EXT4_I(inode)->i_data,
1306                 sizeof(EXT4_I(inode)->i_data));
1307
1308         /* set size of new block */
1309         neh = ext_block_hdr(bh);
1310         /* old root could have indexes or leaves
1311          * so calculate e_max right way */
1312         if (ext_depth(inode))
1313                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1314         else
1315                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1316         neh->eh_magic = EXT4_EXT_MAGIC;
1317         ext4_extent_block_csum_set(inode, neh);
1318         set_buffer_uptodate(bh);
1319         unlock_buffer(bh);
1320
1321         err = ext4_handle_dirty_metadata(handle, inode, bh);
1322         if (err)
1323                 goto out;
1324
1325         /* Update top-level index: num,max,pointer */
1326         neh = ext_inode_hdr(inode);
1327         neh->eh_entries = cpu_to_le16(1);
1328         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1329         if (neh->eh_depth == 0) {
1330                 /* Root extent block becomes index block */
1331                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1332                 EXT_FIRST_INDEX(neh)->ei_block =
1333                         EXT_FIRST_EXTENT(neh)->ee_block;
1334         }
1335         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1336                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1337                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1338                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1339
1340         le16_add_cpu(&neh->eh_depth, 1);
1341         ext4_mark_inode_dirty(handle, inode);
1342 out:
1343         brelse(bh);
1344
1345         return err;
1346 }
1347
1348 /*
1349  * ext4_ext_create_new_leaf:
1350  * finds empty index and adds new leaf.
1351  * if no free index is found, then it requests in-depth growing.
1352  */
1353 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1354                                     unsigned int mb_flags,
1355                                     unsigned int gb_flags,
1356                                     struct ext4_ext_path **ppath,
1357                                     struct ext4_extent *newext)
1358 {
1359         struct ext4_ext_path *path = *ppath;
1360         struct ext4_ext_path *curp;
1361         int depth, i, err = 0;
1362
1363 repeat:
1364         i = depth = ext_depth(inode);
1365
1366         /* walk up to the tree and look for free index entry */
1367         curp = path + depth;
1368         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1369                 i--;
1370                 curp--;
1371         }
1372
1373         /* we use already allocated block for index block,
1374          * so subsequent data blocks should be contiguous */
1375         if (EXT_HAS_FREE_INDEX(curp)) {
1376                 /* if we found index with free entry, then use that
1377                  * entry: create all needed subtree and add new leaf */
1378                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1379                 if (err)
1380                         goto out;
1381
1382                 /* refill path */
1383                 path = ext4_find_extent(inode,
1384                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1385                                     ppath, gb_flags);
1386                 if (IS_ERR(path))
1387                         err = PTR_ERR(path);
1388         } else {
1389                 /* tree is full, time to grow in depth */
1390                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1391                 if (err)
1392                         goto out;
1393
1394                 /* refill path */
1395                 path = ext4_find_extent(inode,
1396                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1397                                     ppath, gb_flags);
1398                 if (IS_ERR(path)) {
1399                         err = PTR_ERR(path);
1400                         goto out;
1401                 }
1402
1403                 /*
1404                  * only first (depth 0 -> 1) produces free space;
1405                  * in all other cases we have to split the grown tree
1406                  */
1407                 depth = ext_depth(inode);
1408                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1409                         /* now we need to split */
1410                         goto repeat;
1411                 }
1412         }
1413
1414 out:
1415         return err;
1416 }
1417
1418 /*
1419  * search the closest allocated block to the left for *logical
1420  * and returns it at @logical + it's physical address at @phys
1421  * if *logical is the smallest allocated block, the function
1422  * returns 0 at @phys
1423  * return value contains 0 (success) or error code
1424  */
1425 static int ext4_ext_search_left(struct inode *inode,
1426                                 struct ext4_ext_path *path,
1427                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1428 {
1429         struct ext4_extent_idx *ix;
1430         struct ext4_extent *ex;
1431         int depth, ee_len;
1432
1433         if (unlikely(path == NULL)) {
1434                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1435                 return -EFSCORRUPTED;
1436         }
1437         depth = path->p_depth;
1438         *phys = 0;
1439
1440         if (depth == 0 && path->p_ext == NULL)
1441                 return 0;
1442
1443         /* usually extent in the path covers blocks smaller
1444          * then *logical, but it can be that extent is the
1445          * first one in the file */
1446
1447         ex = path[depth].p_ext;
1448         ee_len = ext4_ext_get_actual_len(ex);
1449         if (*logical < le32_to_cpu(ex->ee_block)) {
1450                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1451                         EXT4_ERROR_INODE(inode,
1452                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1453                                          *logical, le32_to_cpu(ex->ee_block));
1454                         return -EFSCORRUPTED;
1455                 }
1456                 while (--depth >= 0) {
1457                         ix = path[depth].p_idx;
1458                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1459                                 EXT4_ERROR_INODE(inode,
1460                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1461                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1462                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1463                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1464                                   depth);
1465                                 return -EFSCORRUPTED;
1466                         }
1467                 }
1468                 return 0;
1469         }
1470
1471         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1472                 EXT4_ERROR_INODE(inode,
1473                                  "logical %d < ee_block %d + ee_len %d!",
1474                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1475                 return -EFSCORRUPTED;
1476         }
1477
1478         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1479         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1480         return 0;
1481 }
1482
1483 /*
1484  * search the closest allocated block to the right for *logical
1485  * and returns it at @logical + it's physical address at @phys
1486  * if *logical is the largest allocated block, the function
1487  * returns 0 at @phys
1488  * return value contains 0 (success) or error code
1489  */
1490 static int ext4_ext_search_right(struct inode *inode,
1491                                  struct ext4_ext_path *path,
1492                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1493                                  struct ext4_extent **ret_ex)
1494 {
1495         struct buffer_head *bh = NULL;
1496         struct ext4_extent_header *eh;
1497         struct ext4_extent_idx *ix;
1498         struct ext4_extent *ex;
1499         ext4_fsblk_t block;
1500         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1501         int ee_len;
1502
1503         if (unlikely(path == NULL)) {
1504                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1505                 return -EFSCORRUPTED;
1506         }
1507         depth = path->p_depth;
1508         *phys = 0;
1509
1510         if (depth == 0 && path->p_ext == NULL)
1511                 return 0;
1512
1513         /* usually extent in the path covers blocks smaller
1514          * then *logical, but it can be that extent is the
1515          * first one in the file */
1516
1517         ex = path[depth].p_ext;
1518         ee_len = ext4_ext_get_actual_len(ex);
1519         if (*logical < le32_to_cpu(ex->ee_block)) {
1520                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1521                         EXT4_ERROR_INODE(inode,
1522                                          "first_extent(path[%d].p_hdr) != ex",
1523                                          depth);
1524                         return -EFSCORRUPTED;
1525                 }
1526                 while (--depth >= 0) {
1527                         ix = path[depth].p_idx;
1528                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1529                                 EXT4_ERROR_INODE(inode,
1530                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1531                                                  *logical);
1532                                 return -EFSCORRUPTED;
1533                         }
1534                 }
1535                 goto found_extent;
1536         }
1537
1538         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1539                 EXT4_ERROR_INODE(inode,
1540                                  "logical %d < ee_block %d + ee_len %d!",
1541                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1542                 return -EFSCORRUPTED;
1543         }
1544
1545         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1546                 /* next allocated block in this leaf */
1547                 ex++;
1548                 goto found_extent;
1549         }
1550
1551         /* go up and search for index to the right */
1552         while (--depth >= 0) {
1553                 ix = path[depth].p_idx;
1554                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1555                         goto got_index;
1556         }
1557
1558         /* we've gone up to the root and found no index to the right */
1559         return 0;
1560
1561 got_index:
1562         /* we've found index to the right, let's
1563          * follow it and find the closest allocated
1564          * block to the right */
1565         ix++;
1566         block = ext4_idx_pblock(ix);
1567         while (++depth < path->p_depth) {
1568                 /* subtract from p_depth to get proper eh_depth */
1569                 bh = read_extent_tree_block(inode, block,
1570                                             path->p_depth - depth, 0);
1571                 if (IS_ERR(bh))
1572                         return PTR_ERR(bh);
1573                 eh = ext_block_hdr(bh);
1574                 ix = EXT_FIRST_INDEX(eh);
1575                 block = ext4_idx_pblock(ix);
1576                 put_bh(bh);
1577         }
1578
1579         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1580         if (IS_ERR(bh))
1581                 return PTR_ERR(bh);
1582         eh = ext_block_hdr(bh);
1583         ex = EXT_FIRST_EXTENT(eh);
1584 found_extent:
1585         *logical = le32_to_cpu(ex->ee_block);
1586         *phys = ext4_ext_pblock(ex);
1587         *ret_ex = ex;
1588         if (bh)
1589                 put_bh(bh);
1590         return 0;
1591 }
1592
1593 /*
1594  * ext4_ext_next_allocated_block:
1595  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1596  * NOTE: it considers block number from index entry as
1597  * allocated block. Thus, index entries have to be consistent
1598  * with leaves.
1599  */
1600 ext4_lblk_t
1601 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1602 {
1603         int depth;
1604
1605         BUG_ON(path == NULL);
1606         depth = path->p_depth;
1607
1608         if (depth == 0 && path->p_ext == NULL)
1609                 return EXT_MAX_BLOCKS;
1610
1611         while (depth >= 0) {
1612                 if (depth == path->p_depth) {
1613                         /* leaf */
1614                         if (path[depth].p_ext &&
1615                                 path[depth].p_ext !=
1616                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1617                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1618                 } else {
1619                         /* index */
1620                         if (path[depth].p_idx !=
1621                                         EXT_LAST_INDEX(path[depth].p_hdr))
1622                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1623                 }
1624                 depth--;
1625         }
1626
1627         return EXT_MAX_BLOCKS;
1628 }
1629
1630 /*
1631  * ext4_ext_next_leaf_block:
1632  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1633  */
1634 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1635 {
1636         int depth;
1637
1638         BUG_ON(path == NULL);
1639         depth = path->p_depth;
1640
1641         /* zero-tree has no leaf blocks at all */
1642         if (depth == 0)
1643                 return EXT_MAX_BLOCKS;
1644
1645         /* go to index block */
1646         depth--;
1647
1648         while (depth >= 0) {
1649                 if (path[depth].p_idx !=
1650                                 EXT_LAST_INDEX(path[depth].p_hdr))
1651                         return (ext4_lblk_t)
1652                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1653                 depth--;
1654         }
1655
1656         return EXT_MAX_BLOCKS;
1657 }
1658
1659 /*
1660  * ext4_ext_correct_indexes:
1661  * if leaf gets modified and modified extent is first in the leaf,
1662  * then we have to correct all indexes above.
1663  * TODO: do we need to correct tree in all cases?
1664  */
1665 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1666                                 struct ext4_ext_path *path)
1667 {
1668         struct ext4_extent_header *eh;
1669         int depth = ext_depth(inode);
1670         struct ext4_extent *ex;
1671         __le32 border;
1672         int k, err = 0;
1673
1674         eh = path[depth].p_hdr;
1675         ex = path[depth].p_ext;
1676
1677         if (unlikely(ex == NULL || eh == NULL)) {
1678                 EXT4_ERROR_INODE(inode,
1679                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1680                 return -EFSCORRUPTED;
1681         }
1682
1683         if (depth == 0) {
1684                 /* there is no tree at all */
1685                 return 0;
1686         }
1687
1688         if (ex != EXT_FIRST_EXTENT(eh)) {
1689                 /* we correct tree if first leaf got modified only */
1690                 return 0;
1691         }
1692
1693         /*
1694          * TODO: we need correction if border is smaller than current one
1695          */
1696         k = depth - 1;
1697         border = path[depth].p_ext->ee_block;
1698         err = ext4_ext_get_access(handle, inode, path + k);
1699         if (err)
1700                 return err;
1701         path[k].p_idx->ei_block = border;
1702         err = ext4_ext_dirty(handle, inode, path + k);
1703         if (err)
1704                 return err;
1705
1706         while (k--) {
1707                 /* change all left-side indexes */
1708                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1709                         break;
1710                 err = ext4_ext_get_access(handle, inode, path + k);
1711                 if (err)
1712                         break;
1713                 path[k].p_idx->ei_block = border;
1714                 err = ext4_ext_dirty(handle, inode, path + k);
1715                 if (err)
1716                         break;
1717         }
1718
1719         return err;
1720 }
1721
1722 int
1723 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1724                                 struct ext4_extent *ex2)
1725 {
1726         unsigned short ext1_ee_len, ext2_ee_len;
1727
1728         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1729                 return 0;
1730
1731         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1732         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1733
1734         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1735                         le32_to_cpu(ex2->ee_block))
1736                 return 0;
1737
1738         /*
1739          * To allow future support for preallocated extents to be added
1740          * as an RO_COMPAT feature, refuse to merge to extents if
1741          * this can result in the top bit of ee_len being set.
1742          */
1743         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1744                 return 0;
1745         /*
1746          * The check for IO to unwritten extent is somewhat racy as we
1747          * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after
1748          * dropping i_data_sem. But reserved blocks should save us in that
1749          * case.
1750          */
1751         if (ext4_ext_is_unwritten(ex1) &&
1752             (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1753              atomic_read(&EXT4_I(inode)->i_unwritten) ||
1754              (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1755                 return 0;
1756 #ifdef AGGRESSIVE_TEST
1757         if (ext1_ee_len >= 4)
1758                 return 0;
1759 #endif
1760
1761         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1762                 return 1;
1763         return 0;
1764 }
1765
1766 /*
1767  * This function tries to merge the "ex" extent to the next extent in the tree.
1768  * It always tries to merge towards right. If you want to merge towards
1769  * left, pass "ex - 1" as argument instead of "ex".
1770  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1771  * 1 if they got merged.
1772  */
1773 static int ext4_ext_try_to_merge_right(struct inode *inode,
1774                                  struct ext4_ext_path *path,
1775                                  struct ext4_extent *ex)
1776 {
1777         struct ext4_extent_header *eh;
1778         unsigned int depth, len;
1779         int merge_done = 0, unwritten;
1780
1781         depth = ext_depth(inode);
1782         BUG_ON(path[depth].p_hdr == NULL);
1783         eh = path[depth].p_hdr;
1784
1785         while (ex < EXT_LAST_EXTENT(eh)) {
1786                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1787                         break;
1788                 /* merge with next extent! */
1789                 unwritten = ext4_ext_is_unwritten(ex);
1790                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1791                                 + ext4_ext_get_actual_len(ex + 1));
1792                 if (unwritten)
1793                         ext4_ext_mark_unwritten(ex);
1794
1795                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1796                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1797                                 * sizeof(struct ext4_extent);
1798                         memmove(ex + 1, ex + 2, len);
1799                 }
1800                 le16_add_cpu(&eh->eh_entries, -1);
1801                 merge_done = 1;
1802                 WARN_ON(eh->eh_entries == 0);
1803                 if (!eh->eh_entries)
1804                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1805         }
1806
1807         return merge_done;
1808 }
1809
1810 /*
1811  * This function does a very simple check to see if we can collapse
1812  * an extent tree with a single extent tree leaf block into the inode.
1813  */
1814 static void ext4_ext_try_to_merge_up(handle_t *handle,
1815                                      struct inode *inode,
1816                                      struct ext4_ext_path *path)
1817 {
1818         size_t s;
1819         unsigned max_root = ext4_ext_space_root(inode, 0);
1820         ext4_fsblk_t blk;
1821
1822         if ((path[0].p_depth != 1) ||
1823             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1824             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1825                 return;
1826
1827         /*
1828          * We need to modify the block allocation bitmap and the block
1829          * group descriptor to release the extent tree block.  If we
1830          * can't get the journal credits, give up.
1831          */
1832         if (ext4_journal_extend(handle, 2))
1833                 return;
1834
1835         /*
1836          * Copy the extent data up to the inode
1837          */
1838         blk = ext4_idx_pblock(path[0].p_idx);
1839         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1840                 sizeof(struct ext4_extent_idx);
1841         s += sizeof(struct ext4_extent_header);
1842
1843         path[1].p_maxdepth = path[0].p_maxdepth;
1844         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1845         path[0].p_depth = 0;
1846         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1847                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1848         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1849
1850         brelse(path[1].p_bh);
1851         ext4_free_blocks(handle, inode, NULL, blk, 1,
1852                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1853 }
1854
1855 /*
1856  * This function tries to merge the @ex extent to neighbours in the tree.
1857  * return 1 if merge left else 0.
1858  */
1859 static void ext4_ext_try_to_merge(handle_t *handle,
1860                                   struct inode *inode,
1861                                   struct ext4_ext_path *path,
1862                                   struct ext4_extent *ex) {
1863         struct ext4_extent_header *eh;
1864         unsigned int depth;
1865         int merge_done = 0;
1866
1867         depth = ext_depth(inode);
1868         BUG_ON(path[depth].p_hdr == NULL);
1869         eh = path[depth].p_hdr;
1870
1871         if (ex > EXT_FIRST_EXTENT(eh))
1872                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1873
1874         if (!merge_done)
1875                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1876
1877         ext4_ext_try_to_merge_up(handle, inode, path);
1878 }
1879
1880 /*
1881  * check if a portion of the "newext" extent overlaps with an
1882  * existing extent.
1883  *
1884  * If there is an overlap discovered, it updates the length of the newext
1885  * such that there will be no overlap, and then returns 1.
1886  * If there is no overlap found, it returns 0.
1887  */
1888 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1889                                            struct inode *inode,
1890                                            struct ext4_extent *newext,
1891                                            struct ext4_ext_path *path)
1892 {
1893         ext4_lblk_t b1, b2;
1894         unsigned int depth, len1;
1895         unsigned int ret = 0;
1896
1897         b1 = le32_to_cpu(newext->ee_block);
1898         len1 = ext4_ext_get_actual_len(newext);
1899         depth = ext_depth(inode);
1900         if (!path[depth].p_ext)
1901                 goto out;
1902         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1903
1904         /*
1905          * get the next allocated block if the extent in the path
1906          * is before the requested block(s)
1907          */
1908         if (b2 < b1) {
1909                 b2 = ext4_ext_next_allocated_block(path);
1910                 if (b2 == EXT_MAX_BLOCKS)
1911                         goto out;
1912                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1913         }
1914
1915         /* check for wrap through zero on extent logical start block*/
1916         if (b1 + len1 < b1) {
1917                 len1 = EXT_MAX_BLOCKS - b1;
1918                 newext->ee_len = cpu_to_le16(len1);
1919                 ret = 1;
1920         }
1921
1922         /* check for overlap */
1923         if (b1 + len1 > b2) {
1924                 newext->ee_len = cpu_to_le16(b2 - b1);
1925                 ret = 1;
1926         }
1927 out:
1928         return ret;
1929 }
1930
1931 /*
1932  * ext4_ext_insert_extent:
1933  * tries to merge requsted extent into the existing extent or
1934  * inserts requested extent as new one into the tree,
1935  * creating new leaf in the no-space case.
1936  */
1937 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1938                                 struct ext4_ext_path **ppath,
1939                                 struct ext4_extent *newext, int gb_flags)
1940 {
1941         struct ext4_ext_path *path = *ppath;
1942         struct ext4_extent_header *eh;
1943         struct ext4_extent *ex, *fex;
1944         struct ext4_extent *nearex; /* nearest extent */
1945         struct ext4_ext_path *npath = NULL;
1946         int depth, len, err;
1947         ext4_lblk_t next;
1948         int mb_flags = 0, unwritten;
1949
1950         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1951                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1952         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1953                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1954                 return -EFSCORRUPTED;
1955         }
1956         depth = ext_depth(inode);
1957         ex = path[depth].p_ext;
1958         eh = path[depth].p_hdr;
1959         if (unlikely(path[depth].p_hdr == NULL)) {
1960                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1961                 return -EFSCORRUPTED;
1962         }
1963
1964         /* try to insert block into found extent and return */
1965         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1966
1967                 /*
1968                  * Try to see whether we should rather test the extent on
1969                  * right from ex, or from the left of ex. This is because
1970                  * ext4_find_extent() can return either extent on the
1971                  * left, or on the right from the searched position. This
1972                  * will make merging more effective.
1973                  */
1974                 if (ex < EXT_LAST_EXTENT(eh) &&
1975                     (le32_to_cpu(ex->ee_block) +
1976                     ext4_ext_get_actual_len(ex) <
1977                     le32_to_cpu(newext->ee_block))) {
1978                         ex += 1;
1979                         goto prepend;
1980                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1981                            (le32_to_cpu(newext->ee_block) +
1982                            ext4_ext_get_actual_len(newext) <
1983                            le32_to_cpu(ex->ee_block)))
1984                         ex -= 1;
1985
1986                 /* Try to append newex to the ex */
1987                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1988                         ext_debug("append [%d]%d block to %u:[%d]%d"
1989                                   "(from %llu)\n",
1990                                   ext4_ext_is_unwritten(newext),
1991                                   ext4_ext_get_actual_len(newext),
1992                                   le32_to_cpu(ex->ee_block),
1993                                   ext4_ext_is_unwritten(ex),
1994                                   ext4_ext_get_actual_len(ex),
1995                                   ext4_ext_pblock(ex));
1996                         err = ext4_ext_get_access(handle, inode,
1997                                                   path + depth);
1998                         if (err)
1999                                 return err;
2000                         unwritten = ext4_ext_is_unwritten(ex);
2001                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2002                                         + ext4_ext_get_actual_len(newext));
2003                         if (unwritten)
2004                                 ext4_ext_mark_unwritten(ex);
2005                         eh = path[depth].p_hdr;
2006                         nearex = ex;
2007                         goto merge;
2008                 }
2009
2010 prepend:
2011                 /* Try to prepend newex to the ex */
2012                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2013                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2014                                   "(from %llu)\n",
2015                                   le32_to_cpu(newext->ee_block),
2016                                   ext4_ext_is_unwritten(newext),
2017                                   ext4_ext_get_actual_len(newext),
2018                                   le32_to_cpu(ex->ee_block),
2019                                   ext4_ext_is_unwritten(ex),
2020                                   ext4_ext_get_actual_len(ex),
2021                                   ext4_ext_pblock(ex));
2022                         err = ext4_ext_get_access(handle, inode,
2023                                                   path + depth);
2024                         if (err)
2025                                 return err;
2026
2027                         unwritten = ext4_ext_is_unwritten(ex);
2028                         ex->ee_block = newext->ee_block;
2029                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2030                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2031                                         + ext4_ext_get_actual_len(newext));
2032                         if (unwritten)
2033                                 ext4_ext_mark_unwritten(ex);
2034                         eh = path[depth].p_hdr;
2035                         nearex = ex;
2036                         goto merge;
2037                 }
2038         }
2039
2040         depth = ext_depth(inode);
2041         eh = path[depth].p_hdr;
2042         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2043                 goto has_space;
2044
2045         /* probably next leaf has space for us? */
2046         fex = EXT_LAST_EXTENT(eh);
2047         next = EXT_MAX_BLOCKS;
2048         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2049                 next = ext4_ext_next_leaf_block(path);
2050         if (next != EXT_MAX_BLOCKS) {
2051                 ext_debug("next leaf block - %u\n", next);
2052                 BUG_ON(npath != NULL);
2053                 npath = ext4_find_extent(inode, next, NULL, 0);
2054                 if (IS_ERR(npath))
2055                         return PTR_ERR(npath);
2056                 BUG_ON(npath->p_depth != path->p_depth);
2057                 eh = npath[depth].p_hdr;
2058                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2059                         ext_debug("next leaf isn't full(%d)\n",
2060                                   le16_to_cpu(eh->eh_entries));
2061                         path = npath;
2062                         goto has_space;
2063                 }
2064                 ext_debug("next leaf has no free space(%d,%d)\n",
2065                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2066         }
2067
2068         /*
2069          * There is no free space in the found leaf.
2070          * We're gonna add a new leaf in the tree.
2071          */
2072         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2073                 mb_flags |= EXT4_MB_USE_RESERVED;
2074         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2075                                        ppath, newext);
2076         if (err)
2077                 goto cleanup;
2078         depth = ext_depth(inode);
2079         eh = path[depth].p_hdr;
2080
2081 has_space:
2082         nearex = path[depth].p_ext;
2083
2084         err = ext4_ext_get_access(handle, inode, path + depth);
2085         if (err)
2086                 goto cleanup;
2087
2088         if (!nearex) {
2089                 /* there is no extent in this leaf, create first one */
2090                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2091                                 le32_to_cpu(newext->ee_block),
2092                                 ext4_ext_pblock(newext),
2093                                 ext4_ext_is_unwritten(newext),
2094                                 ext4_ext_get_actual_len(newext));
2095                 nearex = EXT_FIRST_EXTENT(eh);
2096         } else {
2097                 if (le32_to_cpu(newext->ee_block)
2098                            > le32_to_cpu(nearex->ee_block)) {
2099                         /* Insert after */
2100                         ext_debug("insert %u:%llu:[%d]%d before: "
2101                                         "nearest %p\n",
2102                                         le32_to_cpu(newext->ee_block),
2103                                         ext4_ext_pblock(newext),
2104                                         ext4_ext_is_unwritten(newext),
2105                                         ext4_ext_get_actual_len(newext),
2106                                         nearex);
2107                         nearex++;
2108                 } else {
2109                         /* Insert before */
2110                         BUG_ON(newext->ee_block == nearex->ee_block);
2111                         ext_debug("insert %u:%llu:[%d]%d after: "
2112                                         "nearest %p\n",
2113                                         le32_to_cpu(newext->ee_block),
2114                                         ext4_ext_pblock(newext),
2115                                         ext4_ext_is_unwritten(newext),
2116                                         ext4_ext_get_actual_len(newext),
2117                                         nearex);
2118                 }
2119                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2120                 if (len > 0) {
2121                         ext_debug("insert %u:%llu:[%d]%d: "
2122                                         "move %d extents from 0x%p to 0x%p\n",
2123                                         le32_to_cpu(newext->ee_block),
2124                                         ext4_ext_pblock(newext),
2125                                         ext4_ext_is_unwritten(newext),
2126                                         ext4_ext_get_actual_len(newext),
2127                                         len, nearex, nearex + 1);
2128                         memmove(nearex + 1, nearex,
2129                                 len * sizeof(struct ext4_extent));
2130                 }
2131         }
2132
2133         le16_add_cpu(&eh->eh_entries, 1);
2134         path[depth].p_ext = nearex;
2135         nearex->ee_block = newext->ee_block;
2136         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2137         nearex->ee_len = newext->ee_len;
2138
2139 merge:
2140         /* try to merge extents */
2141         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2142                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2143
2144
2145         /* time to correct all indexes above */
2146         err = ext4_ext_correct_indexes(handle, inode, path);
2147         if (err)
2148                 goto cleanup;
2149
2150         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2151
2152 cleanup:
2153         ext4_ext_drop_refs(npath);
2154         kfree(npath);
2155         return err;
2156 }
2157
2158 static int ext4_fill_fiemap_extents(struct inode *inode,
2159                                     ext4_lblk_t block, ext4_lblk_t num,
2160                                     struct fiemap_extent_info *fieinfo)
2161 {
2162         struct ext4_ext_path *path = NULL;
2163         struct ext4_extent *ex;
2164         struct extent_status es;
2165         ext4_lblk_t next, next_del, start = 0, end = 0;
2166         ext4_lblk_t last = block + num;
2167         int exists, depth = 0, err = 0;
2168         unsigned int flags = 0;
2169         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2170
2171         while (block < last && block != EXT_MAX_BLOCKS) {
2172                 num = last - block;
2173                 /* find extent for this block */
2174                 down_read(&EXT4_I(inode)->i_data_sem);
2175
2176                 path = ext4_find_extent(inode, block, &path, 0);
2177                 if (IS_ERR(path)) {
2178                         up_read(&EXT4_I(inode)->i_data_sem);
2179                         err = PTR_ERR(path);
2180                         path = NULL;
2181                         break;
2182                 }
2183
2184                 depth = ext_depth(inode);
2185                 if (unlikely(path[depth].p_hdr == NULL)) {
2186                         up_read(&EXT4_I(inode)->i_data_sem);
2187                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2188                         err = -EFSCORRUPTED;
2189                         break;
2190                 }
2191                 ex = path[depth].p_ext;
2192                 next = ext4_ext_next_allocated_block(path);
2193
2194                 flags = 0;
2195                 exists = 0;
2196                 if (!ex) {
2197                         /* there is no extent yet, so try to allocate
2198                          * all requested space */
2199                         start = block;
2200                         end = block + num;
2201                 } else if (le32_to_cpu(ex->ee_block) > block) {
2202                         /* need to allocate space before found extent */
2203                         start = block;
2204                         end = le32_to_cpu(ex->ee_block);
2205                         if (block + num < end)
2206                                 end = block + num;
2207                 } else if (block >= le32_to_cpu(ex->ee_block)
2208                                         + ext4_ext_get_actual_len(ex)) {
2209                         /* need to allocate space after found extent */
2210                         start = block;
2211                         end = block + num;
2212                         if (end >= next)
2213                                 end = next;
2214                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2215                         /*
2216                          * some part of requested space is covered
2217                          * by found extent
2218                          */
2219                         start = block;
2220                         end = le32_to_cpu(ex->ee_block)
2221                                 + ext4_ext_get_actual_len(ex);
2222                         if (block + num < end)
2223                                 end = block + num;
2224                         exists = 1;
2225                 } else {
2226                         BUG();
2227                 }
2228                 BUG_ON(end <= start);
2229
2230                 if (!exists) {
2231                         es.es_lblk = start;
2232                         es.es_len = end - start;
2233                         es.es_pblk = 0;
2234                 } else {
2235                         es.es_lblk = le32_to_cpu(ex->ee_block);
2236                         es.es_len = ext4_ext_get_actual_len(ex);
2237                         es.es_pblk = ext4_ext_pblock(ex);
2238                         if (ext4_ext_is_unwritten(ex))
2239                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2240                 }
2241
2242                 /*
2243                  * Find delayed extent and update es accordingly. We call
2244                  * it even in !exists case to find out whether es is the
2245                  * last existing extent or not.
2246                  */
2247                 next_del = ext4_find_delayed_extent(inode, &es);
2248                 if (!exists && next_del) {
2249                         exists = 1;
2250                         flags |= (FIEMAP_EXTENT_DELALLOC |
2251                                   FIEMAP_EXTENT_UNKNOWN);
2252                 }
2253                 up_read(&EXT4_I(inode)->i_data_sem);
2254
2255                 if (unlikely(es.es_len == 0)) {
2256                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2257                         err = -EFSCORRUPTED;
2258                         break;
2259                 }
2260
2261                 /*
2262                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2263                  * we need to check next == EXT_MAX_BLOCKS because it is
2264                  * possible that an extent is with unwritten and delayed
2265                  * status due to when an extent is delayed allocated and
2266                  * is allocated by fallocate status tree will track both of
2267                  * them in a extent.
2268                  *
2269                  * So we could return a unwritten and delayed extent, and
2270                  * its block is equal to 'next'.
2271                  */
2272                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2273                         flags |= FIEMAP_EXTENT_LAST;
2274                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2275                                      next != EXT_MAX_BLOCKS)) {
2276                                 EXT4_ERROR_INODE(inode,
2277                                                  "next extent == %u, next "
2278                                                  "delalloc extent = %u",
2279                                                  next, next_del);
2280                                 err = -EFSCORRUPTED;
2281                                 break;
2282                         }
2283                 }
2284
2285                 if (exists) {
2286                         err = fiemap_fill_next_extent(fieinfo,
2287                                 (__u64)es.es_lblk << blksize_bits,
2288                                 (__u64)es.es_pblk << blksize_bits,
2289                                 (__u64)es.es_len << blksize_bits,
2290                                 flags);
2291                         if (err < 0)
2292                                 break;
2293                         if (err == 1) {
2294                                 err = 0;
2295                                 break;
2296                         }
2297                 }
2298
2299                 block = es.es_lblk + es.es_len;
2300         }
2301
2302         ext4_ext_drop_refs(path);
2303         kfree(path);
2304         return err;
2305 }
2306
2307 /*
2308  * ext4_ext_determine_hole - determine hole around given block
2309  * @inode:      inode we lookup in
2310  * @path:       path in extent tree to @lblk
2311  * @lblk:       pointer to logical block around which we want to determine hole
2312  *
2313  * Determine hole length (and start if easily possible) around given logical
2314  * block. We don't try too hard to find the beginning of the hole but @path
2315  * actually points to extent before @lblk, we provide it.
2316  *
2317  * The function returns the length of a hole starting at @lblk. We update @lblk
2318  * to the beginning of the hole if we managed to find it.
2319  */
2320 static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2321                                            struct ext4_ext_path *path,
2322                                            ext4_lblk_t *lblk)
2323 {
2324         int depth = ext_depth(inode);
2325         struct ext4_extent *ex;
2326         ext4_lblk_t len;
2327
2328         ex = path[depth].p_ext;
2329         if (ex == NULL) {
2330                 /* there is no extent yet, so gap is [0;-] */
2331                 *lblk = 0;
2332                 len = EXT_MAX_BLOCKS;
2333         } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2334                 len = le32_to_cpu(ex->ee_block) - *lblk;
2335         } else if (*lblk >= le32_to_cpu(ex->ee_block)
2336                         + ext4_ext_get_actual_len(ex)) {
2337                 ext4_lblk_t next;
2338
2339                 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2340                 next = ext4_ext_next_allocated_block(path);
2341                 BUG_ON(next == *lblk);
2342                 len = next - *lblk;
2343         } else {
2344                 BUG();
2345         }
2346         return len;
2347 }
2348
2349 /*
2350  * ext4_ext_put_gap_in_cache:
2351  * calculate boundaries of the gap that the requested block fits into
2352  * and cache this gap
2353  */
2354 static void
2355 ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2356                           ext4_lblk_t hole_len)
2357 {
2358         struct extent_status es;
2359
2360         ext4_es_find_delayed_extent_range(inode, hole_start,
2361                                           hole_start + hole_len - 1, &es);
2362         if (es.es_len) {
2363                 /* There's delayed extent containing lblock? */
2364                 if (es.es_lblk <= hole_start)
2365                         return;
2366                 hole_len = min(es.es_lblk - hole_start, hole_len);
2367         }
2368         ext_debug(" -> %u:%u\n", hole_start, hole_len);
2369         ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2370                               EXTENT_STATUS_HOLE);
2371 }
2372
2373 /*
2374  * ext4_ext_rm_idx:
2375  * removes index from the index block.
2376  */
2377 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2378                         struct ext4_ext_path *path, int depth)
2379 {
2380         int err;
2381         ext4_fsblk_t leaf;
2382
2383         /* free index block */
2384         depth--;
2385         path = path + depth;
2386         leaf = ext4_idx_pblock(path->p_idx);
2387         if (unlikely(path->p_hdr->eh_entries == 0)) {
2388                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2389                 return -EFSCORRUPTED;
2390         }
2391         err = ext4_ext_get_access(handle, inode, path);
2392         if (err)
2393                 return err;
2394
2395         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2396                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2397                 len *= sizeof(struct ext4_extent_idx);
2398                 memmove(path->p_idx, path->p_idx + 1, len);
2399         }
2400
2401         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2402         err = ext4_ext_dirty(handle, inode, path);
2403         if (err)
2404                 return err;
2405         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2406         trace_ext4_ext_rm_idx(inode, leaf);
2407
2408         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2409                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2410
2411         while (--depth >= 0) {
2412                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2413                         break;
2414                 path--;
2415                 err = ext4_ext_get_access(handle, inode, path);
2416                 if (err)
2417                         break;
2418                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2419                 err = ext4_ext_dirty(handle, inode, path);
2420                 if (err)
2421                         break;
2422         }
2423         return err;
2424 }
2425
2426 /*
2427  * ext4_ext_calc_credits_for_single_extent:
2428  * This routine returns max. credits that needed to insert an extent
2429  * to the extent tree.
2430  * When pass the actual path, the caller should calculate credits
2431  * under i_data_sem.
2432  */
2433 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2434                                                 struct ext4_ext_path *path)
2435 {
2436         if (path) {
2437                 int depth = ext_depth(inode);
2438                 int ret = 0;
2439
2440                 /* probably there is space in leaf? */
2441                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2442                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2443
2444                         /*
2445                          *  There are some space in the leaf tree, no
2446                          *  need to account for leaf block credit
2447                          *
2448                          *  bitmaps and block group descriptor blocks
2449                          *  and other metadata blocks still need to be
2450                          *  accounted.
2451                          */
2452                         /* 1 bitmap, 1 block group descriptor */
2453                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2454                         return ret;
2455                 }
2456         }
2457
2458         return ext4_chunk_trans_blocks(inode, nrblocks);
2459 }
2460
2461 /*
2462  * How many index/leaf blocks need to change/allocate to add @extents extents?
2463  *
2464  * If we add a single extent, then in the worse case, each tree level
2465  * index/leaf need to be changed in case of the tree split.
2466  *
2467  * If more extents are inserted, they could cause the whole tree split more
2468  * than once, but this is really rare.
2469  */
2470 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2471 {
2472         int index;
2473         int depth;
2474
2475         /* If we are converting the inline data, only one is needed here. */
2476         if (ext4_has_inline_data(inode))
2477                 return 1;
2478
2479         depth = ext_depth(inode);
2480
2481         if (extents <= 1)
2482                 index = depth * 2;
2483         else
2484                 index = depth * 3;
2485
2486         return index;
2487 }
2488
2489 static inline int get_default_free_blocks_flags(struct inode *inode)
2490 {
2491         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2492                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2493         else if (ext4_should_journal_data(inode))
2494                 return EXT4_FREE_BLOCKS_FORGET;
2495         return 0;
2496 }
2497
2498 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2499                               struct ext4_extent *ex,
2500                               long long *partial_cluster,
2501                               ext4_lblk_t from, ext4_lblk_t to)
2502 {
2503         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2504         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2505         ext4_fsblk_t pblk;
2506         int flags = get_default_free_blocks_flags(inode);
2507
2508         /*
2509          * For bigalloc file systems, we never free a partial cluster
2510          * at the beginning of the extent.  Instead, we make a note
2511          * that we tried freeing the cluster, and check to see if we
2512          * need to free it on a subsequent call to ext4_remove_blocks,
2513          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2514          */
2515         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2516
2517         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2518         /*
2519          * If we have a partial cluster, and it's different from the
2520          * cluster of the last block, we need to explicitly free the
2521          * partial cluster here.
2522          */
2523         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2524         if (*partial_cluster > 0 &&
2525             *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2526                 ext4_free_blocks(handle, inode, NULL,
2527                                  EXT4_C2B(sbi, *partial_cluster),
2528                                  sbi->s_cluster_ratio, flags);
2529                 *partial_cluster = 0;
2530         }
2531
2532 #ifdef EXTENTS_STATS
2533         {
2534                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2535                 spin_lock(&sbi->s_ext_stats_lock);
2536                 sbi->s_ext_blocks += ee_len;
2537                 sbi->s_ext_extents++;
2538                 if (ee_len < sbi->s_ext_min)
2539                         sbi->s_ext_min = ee_len;
2540                 if (ee_len > sbi->s_ext_max)
2541                         sbi->s_ext_max = ee_len;
2542                 if (ext_depth(inode) > sbi->s_depth_max)
2543                         sbi->s_depth_max = ext_depth(inode);
2544                 spin_unlock(&sbi->s_ext_stats_lock);
2545         }
2546 #endif
2547         if (from >= le32_to_cpu(ex->ee_block)
2548             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2549                 /* tail removal */
2550                 ext4_lblk_t num;
2551                 long long first_cluster;
2552
2553                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2554                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2555                 /*
2556                  * Usually we want to free partial cluster at the end of the
2557                  * extent, except for the situation when the cluster is still
2558                  * used by any other extent (partial_cluster is negative).
2559                  */
2560                 if (*partial_cluster < 0 &&
2561                     *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))
2562                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2563
2564                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2565                           num, pblk, *partial_cluster);
2566                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2567                 /*
2568                  * If the block range to be freed didn't start at the
2569                  * beginning of a cluster, and we removed the entire
2570                  * extent and the cluster is not used by any other extent,
2571                  * save the partial cluster here, since we might need to
2572                  * delete if we determine that the truncate or punch hole
2573                  * operation has removed all of the blocks in the cluster.
2574                  * If that cluster is used by another extent, preserve its
2575                  * negative value so it isn't freed later on.
2576                  *
2577                  * If the whole extent wasn't freed, we've reached the
2578                  * start of the truncated/punched region and have finished
2579                  * removing blocks.  If there's a partial cluster here it's
2580                  * shared with the remainder of the extent and is no longer
2581                  * a candidate for removal.
2582                  */
2583                 if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {
2584                         first_cluster = (long long) EXT4_B2C(sbi, pblk);
2585                         if (first_cluster != -*partial_cluster)
2586                                 *partial_cluster = first_cluster;
2587                 } else {
2588                         *partial_cluster = 0;
2589                 }
2590         } else
2591                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2592                            "%u-%u from %u:%u",
2593                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2594         return 0;
2595 }
2596
2597
2598 /*
2599  * ext4_ext_rm_leaf() Removes the extents associated with the
2600  * blocks appearing between "start" and "end".  Both "start"
2601  * and "end" must appear in the same extent or EIO is returned.
2602  *
2603  * @handle: The journal handle
2604  * @inode:  The files inode
2605  * @path:   The path to the leaf
2606  * @partial_cluster: The cluster which we'll have to free if all extents
2607  *                   has been released from it.  However, if this value is
2608  *                   negative, it's a cluster just to the right of the
2609  *                   punched region and it must not be freed.
2610  * @start:  The first block to remove
2611  * @end:   The last block to remove
2612  */
2613 static int
2614 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2615                  struct ext4_ext_path *path,
2616                  long long *partial_cluster,
2617                  ext4_lblk_t start, ext4_lblk_t end)
2618 {
2619         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2620         int err = 0, correct_index = 0;
2621         int depth = ext_depth(inode), credits;
2622         struct ext4_extent_header *eh;
2623         ext4_lblk_t a, b;
2624         unsigned num;
2625         ext4_lblk_t ex_ee_block;
2626         unsigned short ex_ee_len;
2627         unsigned unwritten = 0;
2628         struct ext4_extent *ex;
2629         ext4_fsblk_t pblk;
2630
2631         /* the header must be checked already in ext4_ext_remove_space() */
2632         ext_debug("truncate since %u in leaf to %u\n", start, end);
2633         if (!path[depth].p_hdr)
2634                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2635         eh = path[depth].p_hdr;
2636         if (unlikely(path[depth].p_hdr == NULL)) {
2637                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2638                 return -EFSCORRUPTED;
2639         }
2640         /* find where to start removing */
2641         ex = path[depth].p_ext;
2642         if (!ex)
2643                 ex = EXT_LAST_EXTENT(eh);
2644
2645         ex_ee_block = le32_to_cpu(ex->ee_block);
2646         ex_ee_len = ext4_ext_get_actual_len(ex);
2647
2648         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2649
2650         while (ex >= EXT_FIRST_EXTENT(eh) &&
2651                         ex_ee_block + ex_ee_len > start) {
2652
2653                 if (ext4_ext_is_unwritten(ex))
2654                         unwritten = 1;
2655                 else
2656                         unwritten = 0;
2657
2658                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2659                           unwritten, ex_ee_len);
2660                 path[depth].p_ext = ex;
2661
2662                 a = ex_ee_block > start ? ex_ee_block : start;
2663                 b = ex_ee_block+ex_ee_len - 1 < end ?
2664                         ex_ee_block+ex_ee_len - 1 : end;
2665
2666                 ext_debug("  border %u:%u\n", a, b);
2667
2668                 /* If this extent is beyond the end of the hole, skip it */
2669                 if (end < ex_ee_block) {
2670                         /*
2671                          * We're going to skip this extent and move to another,
2672                          * so note that its first cluster is in use to avoid
2673                          * freeing it when removing blocks.  Eventually, the
2674                          * right edge of the truncated/punched region will
2675                          * be just to the left.
2676                          */
2677                         if (sbi->s_cluster_ratio > 1) {
2678                                 pblk = ext4_ext_pblock(ex);
2679                                 *partial_cluster =
2680                                         -(long long) EXT4_B2C(sbi, pblk);
2681                         }
2682                         ex--;
2683                         ex_ee_block = le32_to_cpu(ex->ee_block);
2684                         ex_ee_len = ext4_ext_get_actual_len(ex);
2685                         continue;
2686                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2687                         EXT4_ERROR_INODE(inode,
2688                                          "can not handle truncate %u:%u "
2689                                          "on extent %u:%u",
2690                                          start, end, ex_ee_block,
2691                                          ex_ee_block + ex_ee_len - 1);
2692                         err = -EFSCORRUPTED;
2693                         goto out;
2694                 } else if (a != ex_ee_block) {
2695                         /* remove tail of the extent */
2696                         num = a - ex_ee_block;
2697                 } else {
2698                         /* remove whole extent: excellent! */
2699                         num = 0;
2700                 }
2701                 /*
2702                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2703                  * descriptor) for each block group; assume two block
2704                  * groups plus ex_ee_len/blocks_per_block_group for
2705                  * the worst case
2706                  */
2707                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2708                 if (ex == EXT_FIRST_EXTENT(eh)) {
2709                         correct_index = 1;
2710                         credits += (ext_depth(inode)) + 1;
2711                 }
2712                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2713
2714                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2715                 if (err)
2716                         goto out;
2717
2718                 err = ext4_ext_get_access(handle, inode, path + depth);
2719                 if (err)
2720                         goto out;
2721
2722                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2723                                          a, b);
2724                 if (err)
2725                         goto out;
2726
2727                 if (num == 0)
2728                         /* this extent is removed; mark slot entirely unused */
2729                         ext4_ext_store_pblock(ex, 0);
2730
2731                 ex->ee_len = cpu_to_le16(num);
2732                 /*
2733                  * Do not mark unwritten if all the blocks in the
2734                  * extent have been removed.
2735                  */
2736                 if (unwritten && num)
2737                         ext4_ext_mark_unwritten(ex);
2738                 /*
2739                  * If the extent was completely released,
2740                  * we need to remove it from the leaf
2741                  */
2742                 if (num == 0) {
2743                         if (end != EXT_MAX_BLOCKS - 1) {
2744                                 /*
2745                                  * For hole punching, we need to scoot all the
2746                                  * extents up when an extent is removed so that
2747                                  * we dont have blank extents in the middle
2748                                  */
2749                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2750                                         sizeof(struct ext4_extent));
2751
2752                                 /* Now get rid of the one at the end */
2753                                 memset(EXT_LAST_EXTENT(eh), 0,
2754                                         sizeof(struct ext4_extent));
2755                         }
2756                         le16_add_cpu(&eh->eh_entries, -1);
2757                 }
2758
2759                 err = ext4_ext_dirty(handle, inode, path + depth);
2760                 if (err)
2761                         goto out;
2762
2763                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2764                                 ext4_ext_pblock(ex));
2765                 ex--;
2766                 ex_ee_block = le32_to_cpu(ex->ee_block);
2767                 ex_ee_len = ext4_ext_get_actual_len(ex);
2768         }
2769
2770         if (correct_index && eh->eh_entries)
2771                 err = ext4_ext_correct_indexes(handle, inode, path);
2772
2773         /*
2774          * If there's a partial cluster and at least one extent remains in
2775          * the leaf, free the partial cluster if it isn't shared with the
2776          * current extent.  If it is shared with the current extent
2777          * we zero partial_cluster because we've reached the start of the
2778          * truncated/punched region and we're done removing blocks.
2779          */
2780         if (*partial_cluster > 0 && ex >= EXT_FIRST_EXTENT(eh)) {
2781                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2782                 if (*partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2783                         ext4_free_blocks(handle, inode, NULL,
2784                                          EXT4_C2B(sbi, *partial_cluster),
2785                                          sbi->s_cluster_ratio,
2786                                          get_default_free_blocks_flags(inode));
2787                 }
2788                 *partial_cluster = 0;
2789         }
2790
2791         /* if this leaf is free, then we should
2792          * remove it from index block above */
2793         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2794                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2795
2796 out:
2797         return err;
2798 }
2799
2800 /*
2801  * ext4_ext_more_to_rm:
2802  * returns 1 if current index has to be freed (even partial)
2803  */
2804 static int
2805 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2806 {
2807         BUG_ON(path->p_idx == NULL);
2808
2809         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2810                 return 0;
2811
2812         /*
2813          * if truncate on deeper level happened, it wasn't partial,
2814          * so we have to consider current index for truncation
2815          */
2816         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2817                 return 0;
2818         return 1;
2819 }
2820
2821 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2822                           ext4_lblk_t end)
2823 {
2824         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2825         int depth = ext_depth(inode);
2826         struct ext4_ext_path *path = NULL;
2827         long long partial_cluster = 0;
2828         handle_t *handle;
2829         int i = 0, err = 0;
2830
2831         ext_debug("truncate since %u to %u\n", start, end);
2832
2833         /* probably first extent we're gonna free will be last in block */
2834         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2835         if (IS_ERR(handle))
2836                 return PTR_ERR(handle);
2837
2838 again:
2839         trace_ext4_ext_remove_space(inode, start, end, depth);
2840
2841         /*
2842          * Check if we are removing extents inside the extent tree. If that
2843          * is the case, we are going to punch a hole inside the extent tree
2844          * so we have to check whether we need to split the extent covering
2845          * the last block to remove so we can easily remove the part of it
2846          * in ext4_ext_rm_leaf().
2847          */
2848         if (end < EXT_MAX_BLOCKS - 1) {
2849                 struct ext4_extent *ex;
2850                 ext4_lblk_t ee_block, ex_end, lblk;
2851                 ext4_fsblk_t pblk;
2852
2853                 /* find extent for or closest extent to this block */
2854                 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2855                 if (IS_ERR(path)) {
2856                         ext4_journal_stop(handle);
2857                         return PTR_ERR(path);
2858                 }
2859                 depth = ext_depth(inode);
2860                 /* Leaf not may not exist only if inode has no blocks at all */
2861                 ex = path[depth].p_ext;
2862                 if (!ex) {
2863                         if (depth) {
2864                                 EXT4_ERROR_INODE(inode,
2865                                                  "path[%d].p_hdr == NULL",
2866                                                  depth);
2867                                 err = -EFSCORRUPTED;
2868                         }
2869                         goto out;
2870                 }
2871
2872                 ee_block = le32_to_cpu(ex->ee_block);
2873                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2874
2875                 /*
2876                  * See if the last block is inside the extent, if so split
2877                  * the extent at 'end' block so we can easily remove the
2878                  * tail of the first part of the split extent in
2879                  * ext4_ext_rm_leaf().
2880                  */
2881                 if (end >= ee_block && end < ex_end) {
2882
2883                         /*
2884                          * If we're going to split the extent, note that
2885                          * the cluster containing the block after 'end' is
2886                          * in use to avoid freeing it when removing blocks.
2887                          */
2888                         if (sbi->s_cluster_ratio > 1) {
2889                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2890                                 partial_cluster =
2891                                         -(long long) EXT4_B2C(sbi, pblk);
2892                         }
2893
2894                         /*
2895                          * Split the extent in two so that 'end' is the last
2896                          * block in the first new extent. Also we should not
2897                          * fail removing space due to ENOSPC so try to use
2898                          * reserved block if that happens.
2899                          */
2900                         err = ext4_force_split_extent_at(handle, inode, &path,
2901                                                          end + 1, 1);
2902                         if (err < 0)
2903                                 goto out;
2904
2905                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end) {
2906                         /*
2907                          * If there's an extent to the right its first cluster
2908                          * contains the immediate right boundary of the
2909                          * truncated/punched region.  Set partial_cluster to
2910                          * its negative value so it won't be freed if shared
2911                          * with the current extent.  The end < ee_block case
2912                          * is handled in ext4_ext_rm_leaf().
2913                          */
2914                         lblk = ex_end + 1;
2915                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2916                                                     &ex);
2917                         if (err)
2918                                 goto out;
2919                         if (pblk)
2920                                 partial_cluster =
2921                                         -(long long) EXT4_B2C(sbi, pblk);
2922                 }
2923         }
2924         /*
2925          * We start scanning from right side, freeing all the blocks
2926          * after i_size and walking into the tree depth-wise.
2927          */
2928         depth = ext_depth(inode);
2929         if (path) {
2930                 int k = i = depth;
2931                 while (--k > 0)
2932                         path[k].p_block =
2933                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2934         } else {
2935                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2936                                GFP_NOFS);
2937                 if (path == NULL) {
2938                         ext4_journal_stop(handle);
2939                         return -ENOMEM;
2940                 }
2941                 path[0].p_maxdepth = path[0].p_depth = depth;
2942                 path[0].p_hdr = ext_inode_hdr(inode);
2943                 i = 0;
2944
2945                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2946                         err = -EFSCORRUPTED;
2947                         goto out;
2948                 }
2949         }
2950         err = 0;
2951
2952         while (i >= 0 && err == 0) {
2953                 if (i == depth) {
2954                         /* this is leaf block */
2955                         err = ext4_ext_rm_leaf(handle, inode, path,
2956                                                &partial_cluster, start,
2957                                                end);
2958                         /* root level has p_bh == NULL, brelse() eats this */
2959                         brelse(path[i].p_bh);
2960                         path[i].p_bh = NULL;
2961                         i--;
2962                         continue;
2963                 }
2964
2965                 /* this is index block */
2966                 if (!path[i].p_hdr) {
2967                         ext_debug("initialize header\n");
2968                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2969                 }
2970
2971                 if (!path[i].p_idx) {
2972                         /* this level hasn't been touched yet */
2973                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2974                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2975                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2976                                   path[i].p_hdr,
2977                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2978                 } else {
2979                         /* we were already here, see at next index */
2980                         path[i].p_idx--;
2981                 }
2982
2983                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2984                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2985                                 path[i].p_idx);
2986                 if (ext4_ext_more_to_rm(path + i)) {
2987                         struct buffer_head *bh;
2988                         /* go to the next level */
2989                         ext_debug("move to level %d (block %llu)\n",
2990                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2991                         memset(path + i + 1, 0, sizeof(*path));
2992                         bh = read_extent_tree_block(inode,
2993                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2994                                 EXT4_EX_NOCACHE);
2995                         if (IS_ERR(bh)) {
2996                                 /* should we reset i_size? */
2997                                 err = PTR_ERR(bh);
2998                                 break;
2999                         }
3000                         /* Yield here to deal with large extent trees.
3001                          * Should be a no-op if we did IO above. */
3002                         cond_resched();
3003                         if (WARN_ON(i + 1 > depth)) {
3004                                 err = -EFSCORRUPTED;
3005                                 break;
3006                         }
3007                         path[i + 1].p_bh = bh;
3008
3009                         /* save actual number of indexes since this
3010                          * number is changed at the next iteration */
3011                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3012                         i++;
3013                 } else {
3014                         /* we finished processing this index, go up */
3015                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3016                                 /* index is empty, remove it;
3017                                  * handle must be already prepared by the
3018                                  * truncatei_leaf() */
3019                                 err = ext4_ext_rm_idx(handle, inode, path, i);
3020                         }
3021                         /* root level has p_bh == NULL, brelse() eats this */
3022                         brelse(path[i].p_bh);
3023                         path[i].p_bh = NULL;
3024                         i--;
3025                         ext_debug("return to level %d\n", i);
3026                 }
3027         }
3028
3029         trace_ext4_ext_remove_space_done(inode, start, end, depth,
3030                         partial_cluster, path->p_hdr->eh_entries);
3031
3032         /*
3033          * If we still have something in the partial cluster and we have removed
3034          * even the first extent, then we should free the blocks in the partial
3035          * cluster as well.  (This code will only run when there are no leaves
3036          * to the immediate left of the truncated/punched region.)
3037          */
3038         if (partial_cluster > 0 && err == 0) {
3039                 /* don't zero partial_cluster since it's not used afterwards */
3040                 ext4_free_blocks(handle, inode, NULL,
3041                                  EXT4_C2B(sbi, partial_cluster),
3042                                  sbi->s_cluster_ratio,
3043                                  get_default_free_blocks_flags(inode));
3044         }
3045
3046         /* TODO: flexible tree reduction should be here */
3047         if (path->p_hdr->eh_entries == 0) {
3048                 /*
3049                  * truncate to zero freed all the tree,
3050                  * so we need to correct eh_depth
3051                  */
3052                 err = ext4_ext_get_access(handle, inode, path);
3053                 if (err == 0) {
3054                         ext_inode_hdr(inode)->eh_depth = 0;
3055                         ext_inode_hdr(inode)->eh_max =
3056                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3057                         err = ext4_ext_dirty(handle, inode, path);
3058                 }
3059         }
3060 out:
3061         ext4_ext_drop_refs(path);
3062         kfree(path);
3063         path = NULL;
3064         if (err == -EAGAIN)
3065                 goto again;
3066         ext4_journal_stop(handle);
3067
3068         return err;
3069 }
3070
3071 /*
3072  * called at mount time
3073  */
3074 void ext4_ext_init(struct super_block *sb)
3075 {
3076         /*
3077          * possible initialization would be here
3078          */
3079
3080         if (ext4_has_feature_extents(sb)) {
3081 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3082                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3083 #ifdef AGGRESSIVE_TEST
3084                        ", aggressive tests"
3085 #endif
3086 #ifdef CHECK_BINSEARCH
3087                        ", check binsearch"
3088 #endif
3089 #ifdef EXTENTS_STATS
3090                        ", stats"
3091 #endif
3092                        "\n");
3093 #endif
3094 #ifdef EXTENTS_STATS
3095                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3096                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3097                 EXT4_SB(sb)->s_ext_max = 0;
3098 #endif
3099         }
3100 }
3101
3102 /*
3103  * called at umount time
3104  */
3105 void ext4_ext_release(struct super_block *sb)
3106 {
3107         if (!ext4_has_feature_extents(sb))
3108                 return;
3109
3110 #ifdef EXTENTS_STATS
3111         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3112                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3113                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3114                         sbi->s_ext_blocks, sbi->s_ext_extents,
3115                         sbi->s_ext_blocks / sbi->s_ext_extents);
3116                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3117                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3118         }
3119 #endif
3120 }
3121
3122 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3123 {
3124         ext4_lblk_t  ee_block;
3125         ext4_fsblk_t ee_pblock;
3126         unsigned int ee_len;
3127
3128         ee_block  = le32_to_cpu(ex->ee_block);
3129         ee_len    = ext4_ext_get_actual_len(ex);
3130         ee_pblock = ext4_ext_pblock(ex);
3131
3132         if (ee_len == 0)
3133                 return 0;
3134
3135         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3136                                      EXTENT_STATUS_WRITTEN);
3137 }
3138
3139 /* FIXME!! we need to try to merge to left or right after zero-out  */
3140 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3141 {
3142         ext4_fsblk_t ee_pblock;
3143         unsigned int ee_len;
3144
3145         ee_len    = ext4_ext_get_actual_len(ex);
3146         ee_pblock = ext4_ext_pblock(ex);
3147         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3148                                   ee_len);
3149 }
3150
3151 /*
3152  * ext4_split_extent_at() splits an extent at given block.
3153  *
3154  * @handle: the journal handle
3155  * @inode: the file inode
3156  * @path: the path to the extent
3157  * @split: the logical block where the extent is splitted.
3158  * @split_flags: indicates if the extent could be zeroout if split fails, and
3159  *               the states(init or unwritten) of new extents.
3160  * @flags: flags used to insert new extent to extent tree.
3161  *
3162  *
3163  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3164  * of which are deterimined by split_flag.
3165  *
3166  * There are two cases:
3167  *  a> the extent are splitted into two extent.
3168  *  b> split is not needed, and just mark the extent.
3169  *
3170  * return 0 on success.
3171  */
3172 static int ext4_split_extent_at(handle_t *handle,
3173                              struct inode *inode,
3174                              struct ext4_ext_path **ppath,
3175                              ext4_lblk_t split,
3176                              int split_flag,
3177                              int flags)
3178 {
3179         struct ext4_ext_path *path = *ppath;
3180         ext4_fsblk_t newblock;
3181         ext4_lblk_t ee_block;
3182         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3183         struct ext4_extent *ex2 = NULL;
3184         unsigned int ee_len, depth;
3185         int err = 0;
3186
3187         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3188                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3189
3190         ext_debug("ext4_split_extents_at: inode %lu, logical"
3191                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3192
3193         ext4_ext_show_leaf(inode, path);
3194
3195         depth = ext_depth(inode);
3196         ex = path[depth].p_ext;
3197         ee_block = le32_to_cpu(ex->ee_block);
3198         ee_len = ext4_ext_get_actual_len(ex);
3199         newblock = split - ee_block + ext4_ext_pblock(ex);
3200
3201         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3202         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3203                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3204                              EXT4_EXT_MARK_UNWRIT1 |
3205                              EXT4_EXT_MARK_UNWRIT2));
3206
3207         err = ext4_ext_get_access(handle, inode, path + depth);
3208         if (err)
3209                 goto out;
3210
3211         if (split == ee_block) {
3212                 /*
3213                  * case b: block @split is the block that the extent begins with
3214                  * then we just change the state of the extent, and splitting
3215                  * is not needed.
3216                  */
3217                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3218                         ext4_ext_mark_unwritten(ex);
3219                 else
3220                         ext4_ext_mark_initialized(ex);
3221
3222                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3223                         ext4_ext_try_to_merge(handle, inode, path, ex);
3224
3225                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3226                 goto out;
3227         }
3228
3229         /* case a */
3230         memcpy(&orig_ex, ex, sizeof(orig_ex));
3231         ex->ee_len = cpu_to_le16(split - ee_block);
3232         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3233                 ext4_ext_mark_unwritten(ex);
3234
3235         /*
3236          * path may lead to new leaf, not to original leaf any more
3237          * after ext4_ext_insert_extent() returns,
3238          */
3239         err = ext4_ext_dirty(handle, inode, path + depth);
3240         if (err)
3241                 goto fix_extent_len;
3242
3243         ex2 = &newex;
3244         ex2->ee_block = cpu_to_le32(split);
3245         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3246         ext4_ext_store_pblock(ex2, newblock);
3247         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3248                 ext4_ext_mark_unwritten(ex2);
3249
3250         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3251         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3252                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3253                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3254                                 err = ext4_ext_zeroout(inode, ex2);
3255                                 zero_ex.ee_block = ex2->ee_block;
3256                                 zero_ex.ee_len = cpu_to_le16(
3257                                                 ext4_ext_get_actual_len(ex2));
3258                                 ext4_ext_store_pblock(&zero_ex,
3259                                                       ext4_ext_pblock(ex2));
3260                         } else {
3261                                 err = ext4_ext_zeroout(inode, ex);
3262                                 zero_ex.ee_block = ex->ee_block;
3263                                 zero_ex.ee_len = cpu_to_le16(
3264                                                 ext4_ext_get_actual_len(ex));
3265                                 ext4_ext_store_pblock(&zero_ex,
3266                                                       ext4_ext_pblock(ex));
3267                         }
3268                 } else {
3269                         err = ext4_ext_zeroout(inode, &orig_ex);
3270                         zero_ex.ee_block = orig_ex.ee_block;
3271                         zero_ex.ee_len = cpu_to_le16(
3272                                                 ext4_ext_get_actual_len(&orig_ex));
3273                         ext4_ext_store_pblock(&zero_ex,
3274                                               ext4_ext_pblock(&orig_ex));
3275                 }
3276
3277                 if (err)
3278                         goto fix_extent_len;
3279                 /* update the extent length and mark as initialized */
3280                 ex->ee_len = cpu_to_le16(ee_len);
3281                 ext4_ext_try_to_merge(handle, inode, path, ex);
3282                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3283                 if (err)
3284                         goto fix_extent_len;
3285
3286                 /* update extent status tree */
3287                 err = ext4_zeroout_es(inode, &zero_ex);
3288
3289                 goto out;
3290         } else if (err)
3291                 goto fix_extent_len;
3292
3293 out:
3294         ext4_ext_show_leaf(inode, path);
3295         return err;
3296
3297 fix_extent_len:
3298         ex->ee_len = orig_ex.ee_len;
3299         ext4_ext_dirty(handle, inode, path + path->p_depth);
3300         return err;
3301 }
3302
3303 /*
3304  * ext4_split_extents() splits an extent and mark extent which is covered
3305  * by @map as split_flags indicates
3306  *
3307  * It may result in splitting the extent into multiple extents (up to three)
3308  * There are three possibilities:
3309  *   a> There is no split required
3310  *   b> Splits in two extents: Split is happening at either end of the extent
3311  *   c> Splits in three extents: Somone is splitting in middle of the extent
3312  *
3313  */
3314 static int ext4_split_extent(handle_t *handle,
3315                               struct inode *inode,
3316                               struct ext4_ext_path **ppath,
3317                               struct ext4_map_blocks *map,
3318                               int split_flag,
3319                               int flags)
3320 {
3321         struct ext4_ext_path *path = *ppath;
3322         ext4_lblk_t ee_block;
3323         struct ext4_extent *ex;
3324         unsigned int ee_len, depth;
3325         int err = 0;
3326         int unwritten;
3327         int split_flag1, flags1;
3328         int allocated = map->m_len;
3329
3330         depth = ext_depth(inode);
3331         ex = path[depth].p_ext;
3332         ee_block = le32_to_cpu(ex->ee_block);
3333         ee_len = ext4_ext_get_actual_len(ex);
3334         unwritten = ext4_ext_is_unwritten(ex);
3335
3336         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3337                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3338                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3339                 if (unwritten)
3340                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3341                                        EXT4_EXT_MARK_UNWRIT2;
3342                 if (split_flag & EXT4_EXT_DATA_VALID2)
3343                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3344                 err = ext4_split_extent_at(handle, inode, ppath,
3345                                 map->m_lblk + map->m_len, split_flag1, flags1);
3346                 if (err)
3347                         goto out;
3348         } else {
3349                 allocated = ee_len - (map->m_lblk - ee_block);
3350         }
3351         /*
3352          * Update path is required because previous ext4_split_extent_at() may
3353          * result in split of original leaf or extent zeroout.
3354          */
3355         path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3356         if (IS_ERR(path))
3357                 return PTR_ERR(path);
3358         depth = ext_depth(inode);
3359         ex = path[depth].p_ext;
3360         if (!ex) {
3361                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3362                                  (unsigned long) map->m_lblk);
3363                 return -EFSCORRUPTED;
3364         }
3365         unwritten = ext4_ext_is_unwritten(ex);
3366         split_flag1 = 0;
3367
3368         if (map->m_lblk >= ee_block) {
3369                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3370                 if (unwritten) {
3371                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3372                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3373                                                      EXT4_EXT_MARK_UNWRIT2);
3374                 }
3375                 err = ext4_split_extent_at(handle, inode, ppath,
3376                                 map->m_lblk, split_flag1, flags);
3377                 if (err)
3378                         goto out;
3379         }
3380
3381         ext4_ext_show_leaf(inode, path);
3382 out:
3383         return err ? err : allocated;
3384 }
3385
3386 /*
3387  * This function is called by ext4_ext_map_blocks() if someone tries to write
3388  * to an unwritten extent. It may result in splitting the unwritten
3389  * extent into multiple extents (up to three - one initialized and two
3390  * unwritten).
3391  * There are three possibilities:
3392  *   a> There is no split required: Entire extent should be initialized
3393  *   b> Splits in two extents: Write is happening at either end of the extent
3394  *   c> Splits in three extents: Somone is writing in middle of the extent
3395  *
3396  * Pre-conditions:
3397  *  - The extent pointed to by 'path' is unwritten.
3398  *  - The extent pointed to by 'path' contains a superset
3399  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3400  *
3401  * Post-conditions on success:
3402  *  - the returned value is the number of blocks beyond map->l_lblk
3403  *    that are allocated and initialized.
3404  *    It is guaranteed to be >= map->m_len.
3405  */
3406 static int ext4_ext_convert_to_initialized(handle_t *handle,
3407                                            struct inode *inode,
3408                                            struct ext4_map_blocks *map,
3409                                            struct ext4_ext_path **ppath,
3410                                            int flags)
3411 {
3412         struct ext4_ext_path *path = *ppath;
3413         struct ext4_sb_info *sbi;
3414         struct ext4_extent_header *eh;
3415         struct ext4_map_blocks split_map;
3416         struct ext4_extent zero_ex;
3417         struct ext4_extent *ex, *abut_ex;
3418         ext4_lblk_t ee_block, eof_block;
3419         unsigned int ee_len, depth, map_len = map->m_len;
3420         int allocated = 0, max_zeroout = 0;
3421         int err = 0;
3422         int split_flag = 0;
3423
3424         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3425                 "block %llu, max_blocks %u\n", inode->i_ino,
3426                 (unsigned long long)map->m_lblk, map_len);
3427
3428         sbi = EXT4_SB(inode->i_sb);
3429         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3430                 inode->i_sb->s_blocksize_bits;
3431         if (eof_block < map->m_lblk + map_len)
3432                 eof_block = map->m_lblk + map_len;
3433
3434         depth = ext_depth(inode);
3435         eh = path[depth].p_hdr;
3436         ex = path[depth].p_ext;
3437         ee_block = le32_to_cpu(ex->ee_block);
3438         ee_len = ext4_ext_get_actual_len(ex);
3439         zero_ex.ee_len = 0;
3440
3441         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3442
3443         /* Pre-conditions */
3444         BUG_ON(!ext4_ext_is_unwritten(ex));
3445         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3446
3447         /*
3448          * Attempt to transfer newly initialized blocks from the currently
3449          * unwritten extent to its neighbor. This is much cheaper
3450          * than an insertion followed by a merge as those involve costly
3451          * memmove() calls. Transferring to the left is the common case in
3452          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3453          * followed by append writes.
3454          *
3455          * Limitations of the current logic:
3456          *  - L1: we do not deal with writes covering the whole extent.
3457          *    This would require removing the extent if the transfer
3458          *    is possible.
3459          *  - L2: we only attempt to merge with an extent stored in the
3460          *    same extent tree node.
3461          */
3462         if ((map->m_lblk == ee_block) &&
3463                 /* See if we can merge left */
3464                 (map_len < ee_len) &&           /*L1*/
3465                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3466                 ext4_lblk_t prev_lblk;
3467                 ext4_fsblk_t prev_pblk, ee_pblk;
3468                 unsigned int prev_len;
3469
3470                 abut_ex = ex - 1;
3471                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3472                 prev_len = ext4_ext_get_actual_len(abut_ex);
3473                 prev_pblk = ext4_ext_pblock(abut_ex);
3474                 ee_pblk = ext4_ext_pblock(ex);
3475
3476                 /*
3477                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3478                  * upon those conditions:
3479                  * - C1: abut_ex is initialized,
3480                  * - C2: abut_ex is logically abutting ex,
3481                  * - C3: abut_ex is physically abutting ex,
3482                  * - C4: abut_ex can receive the additional blocks without
3483                  *   overflowing the (initialized) length limit.
3484                  */
3485                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3486                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3487                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3488                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3489                         err = ext4_ext_get_access(handle, inode, path + depth);
3490                         if (err)
3491                                 goto out;
3492
3493                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3494                                 map, ex, abut_ex);
3495
3496                         /* Shift the start of ex by 'map_len' blocks */
3497                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3498                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3499                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3500                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3501
3502                         /* Extend abut_ex by 'map_len' blocks */
3503                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3504
3505                         /* Result: number of initialized blocks past m_lblk */
3506                         allocated = map_len;
3507                 }
3508         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3509                    (map_len < ee_len) &&        /*L1*/
3510                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3511                 /* See if we can merge right */
3512                 ext4_lblk_t next_lblk;
3513                 ext4_fsblk_t next_pblk, ee_pblk;
3514                 unsigned int next_len;
3515
3516                 abut_ex = ex + 1;
3517                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3518                 next_len = ext4_ext_get_actual_len(abut_ex);
3519                 next_pblk = ext4_ext_pblock(abut_ex);
3520                 ee_pblk = ext4_ext_pblock(ex);
3521
3522                 /*
3523                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3524                  * upon those conditions:
3525                  * - C1: abut_ex is initialized,
3526                  * - C2: abut_ex is logically abutting ex,
3527                  * - C3: abut_ex is physically abutting ex,
3528                  * - C4: abut_ex can receive the additional blocks without
3529                  *   overflowing the (initialized) length limit.
3530                  */
3531                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3532                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3533                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3534                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3535                         err = ext4_ext_get_access(handle, inode, path + depth);
3536                         if (err)
3537                                 goto out;
3538
3539                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3540                                 map, ex, abut_ex);
3541
3542                         /* Shift the start of abut_ex by 'map_len' blocks */
3543                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3544                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3545                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3546                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3547
3548                         /* Extend abut_ex by 'map_len' blocks */
3549                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3550
3551                         /* Result: number of initialized blocks past m_lblk */
3552                         allocated = map_len;
3553                 }
3554         }
3555         if (allocated) {
3556                 /* Mark the block containing both extents as dirty */
3557                 ext4_ext_dirty(handle, inode, path + depth);
3558
3559                 /* Update path to point to the right extent */
3560                 path[depth].p_ext = abut_ex;
3561                 goto out;
3562         } else
3563                 allocated = ee_len - (map->m_lblk - ee_block);
3564
3565         WARN_ON(map->m_lblk < ee_block);
3566         /*
3567          * It is safe to convert extent to initialized via explicit
3568          * zeroout only if extent is fully inside i_size or new_size.
3569          */
3570         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3571
3572         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3573                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3574                         (inode->i_sb->s_blocksize_bits - 10);
3575
3576         if (ext4_encrypted_inode(inode))
3577                 max_zeroout = 0;
3578
3579         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3580         if (max_zeroout && (ee_len <= max_zeroout)) {
3581                 err = ext4_ext_zeroout(inode, ex);
3582                 if (err)
3583                         goto out;
3584                 zero_ex.ee_block = ex->ee_block;
3585                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3586                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3587
3588                 err = ext4_ext_get_access(handle, inode, path + depth);
3589                 if (err)
3590                         goto out;
3591                 ext4_ext_mark_initialized(ex);
3592                 ext4_ext_try_to_merge(handle, inode, path, ex);
3593                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3594                 goto out;
3595         }
3596
3597         /*
3598          * four cases:
3599          * 1. split the extent into three extents.
3600          * 2. split the extent into two extents, zeroout the first half.
3601          * 3. split the extent into two extents, zeroout the second half.
3602          * 4. split the extent into two extents with out zeroout.
3603          */
3604         split_map.m_lblk = map->m_lblk;
3605         split_map.m_len = map->m_len;
3606
3607         if (max_zeroout && (allocated > map->m_len)) {
3608                 if (allocated <= max_zeroout) {
3609                         /* case 3 */
3610                         zero_ex.ee_block =
3611                                          cpu_to_le32(map->m_lblk);
3612                         zero_ex.ee_len = cpu_to_le16(allocated);
3613                         ext4_ext_store_pblock(&zero_ex,
3614                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3615                         err = ext4_ext_zeroout(inode, &zero_ex);
3616                         if (err)
3617                                 goto out;
3618                         split_map.m_lblk = map->m_lblk;
3619                         split_map.m_len = allocated;
3620                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3621                         /* case 2 */
3622                         if (map->m_lblk != ee_block) {
3623                                 zero_ex.ee_block = ex->ee_block;
3624                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3625                                                         ee_block);
3626                                 ext4_ext_store_pblock(&zero_ex,
3627                                                       ext4_ext_pblock(ex));
3628                                 err = ext4_ext_zeroout(inode, &zero_ex);
3629                                 if (err)
3630                                         goto out;
3631                         }
3632
3633                         split_map.m_lblk = ee_block;
3634                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3635                         allocated = map->m_len;
3636                 }
3637         }
3638
3639         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3640                                 flags);
3641         if (err > 0)
3642                 err = 0;
3643 out:
3644         /* If we have gotten a failure, don't zero out status tree */
3645         if (!err)
3646                 err = ext4_zeroout_es(inode, &zero_ex);
3647         return err ? err : allocated;
3648 }
3649
3650 /*
3651  * This function is called by ext4_ext_map_blocks() from
3652  * ext4_get_blocks_dio_write() when DIO to write
3653  * to an unwritten extent.
3654  *
3655  * Writing to an unwritten extent may result in splitting the unwritten
3656  * extent into multiple initialized/unwritten extents (up to three)
3657  * There are three possibilities:
3658  *   a> There is no split required: Entire extent should be unwritten
3659  *   b> Splits in two extents: Write is happening at either end of the extent
3660  *   c> Splits in three extents: Somone is writing in middle of the extent
3661  *
3662  * This works the same way in the case of initialized -> unwritten conversion.
3663  *
3664  * One of more index blocks maybe needed if the extent tree grow after
3665  * the unwritten extent split. To prevent ENOSPC occur at the IO
3666  * complete, we need to split the unwritten extent before DIO submit
3667  * the IO. The unwritten extent called at this time will be split
3668  * into three unwritten extent(at most). After IO complete, the part
3669  * being filled will be convert to initialized by the end_io callback function
3670  * via ext4_convert_unwritten_extents().
3671  *
3672  * Returns the size of unwritten extent to be written on success.
3673  */
3674 static int ext4_split_convert_extents(handle_t *handle,
3675                                         struct inode *inode,
3676                                         struct ext4_map_blocks *map,
3677                                         struct ext4_ext_path **ppath,
3678                                         int flags)
3679 {
3680         struct ext4_ext_path *path = *ppath;
3681         ext4_lblk_t eof_block;
3682         ext4_lblk_t ee_block;
3683         struct ext4_extent *ex;
3684         unsigned int ee_len;
3685         int split_flag = 0, depth;
3686
3687         ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3688                   __func__, inode->i_ino,
3689                   (unsigned long long)map->m_lblk, map->m_len);
3690
3691         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3692                 inode->i_sb->s_blocksize_bits;
3693         if (eof_block < map->m_lblk + map->m_len)
3694                 eof_block = map->m_lblk + map->m_len;
3695         /*
3696          * It is safe to convert extent to initialized via explicit
3697          * zeroout only if extent is fully insde i_size or new_size.
3698          */
3699         depth = ext_depth(inode);
3700         ex = path[depth].p_ext;
3701         ee_block = le32_to_cpu(ex->ee_block);
3702         ee_len = ext4_ext_get_actual_len(ex);
3703
3704         /* Convert to unwritten */
3705         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3706                 split_flag |= EXT4_EXT_DATA_VALID1;
3707         /* Convert to initialized */
3708         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3709                 split_flag |= ee_block + ee_len <= eof_block ?
3710                               EXT4_EXT_MAY_ZEROOUT : 0;
3711                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3712         }
3713         flags |= EXT4_GET_BLOCKS_PRE_IO;
3714         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3715 }
3716
3717 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3718                                                 struct inode *inode,
3719                                                 struct ext4_map_blocks *map,
3720                                                 struct ext4_ext_path **ppath)
3721 {
3722         struct ext4_ext_path *path = *ppath;
3723         struct ext4_extent *ex;
3724         ext4_lblk_t ee_block;
3725         unsigned int ee_len;
3726         int depth;
3727         int err = 0;
3728
3729         depth = ext_depth(inode);
3730         ex = path[depth].p_ext;
3731         ee_block = le32_to_cpu(ex->ee_block);
3732         ee_len = ext4_ext_get_actual_len(ex);
3733
3734         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3735                 "block %llu, max_blocks %u\n", inode->i_ino,
3736                   (unsigned long long)ee_block, ee_len);
3737
3738         /* If extent is larger than requested it is a clear sign that we still
3739          * have some extent state machine issues left. So extent_split is still
3740          * required.
3741          * TODO: Once all related issues will be fixed this situation should be
3742          * illegal.
3743          */
3744         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3745 #ifdef EXT4_DEBUG
3746                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3747                              " len %u; IO logical block %llu, len %u",
3748                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3749                              (unsigned long long)map->m_lblk, map->m_len);
3750 #endif
3751                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3752                                                  EXT4_GET_BLOCKS_CONVERT);
3753                 if (err < 0)
3754                         return err;
3755                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3756                 if (IS_ERR(path))
3757                         return PTR_ERR(path);
3758                 depth = ext_depth(inode);
3759                 ex = path[depth].p_ext;
3760         }
3761
3762         err = ext4_ext_get_access(handle, inode, path + depth);
3763         if (err)
3764                 goto out;
3765         /* first mark the extent as initialized */
3766         ext4_ext_mark_initialized(ex);
3767
3768         /* note: ext4_ext_correct_indexes() isn't needed here because
3769          * borders are not changed
3770          */
3771         ext4_ext_try_to_merge(handle, inode, path, ex);
3772
3773         /* Mark modified extent as dirty */
3774         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3775 out:
3776         ext4_ext_show_leaf(inode, path);
3777         return err;
3778 }
3779
3780 /*
3781  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3782  */
3783 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3784                               ext4_lblk_t lblk,
3785                               struct ext4_ext_path *path,
3786                               unsigned int len)
3787 {
3788         int i, depth;
3789         struct ext4_extent_header *eh;
3790         struct ext4_extent *last_ex;
3791
3792         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3793                 return 0;
3794
3795         depth = ext_depth(inode);
3796         eh = path[depth].p_hdr;
3797
3798         /*
3799          * We're going to remove EOFBLOCKS_FL entirely in future so we
3800          * do not care for this case anymore. Simply remove the flag
3801          * if there are no extents.
3802          */
3803         if (unlikely(!eh->eh_entries))
3804                 goto out;
3805         last_ex = EXT_LAST_EXTENT(eh);
3806         /*
3807          * We should clear the EOFBLOCKS_FL flag if we are writing the
3808          * last block in the last extent in the file.  We test this by
3809          * first checking to see if the caller to
3810          * ext4_ext_get_blocks() was interested in the last block (or
3811          * a block beyond the last block) in the current extent.  If
3812          * this turns out to be false, we can bail out from this
3813          * function immediately.
3814          */
3815         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3816             ext4_ext_get_actual_len(last_ex))
3817                 return 0;
3818         /*
3819          * If the caller does appear to be planning to write at or
3820          * beyond the end of the current extent, we then test to see
3821          * if the current extent is the last extent in the file, by
3822          * checking to make sure it was reached via the rightmost node
3823          * at each level of the tree.
3824          */
3825         for (i = depth-1; i >= 0; i--)
3826                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3827                         return 0;
3828 out:
3829         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3830         return ext4_mark_inode_dirty(handle, inode);
3831 }
3832
3833 /**
3834  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3835  *
3836  * Return 1 if there is a delalloc block in the range, otherwise 0.
3837  */
3838 int ext4_find_delalloc_range(struct inode *inode,
3839                              ext4_lblk_t lblk_start,
3840                              ext4_lblk_t lblk_end)
3841 {
3842         struct extent_status es;
3843
3844         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3845         if (es.es_len == 0)
3846                 return 0; /* there is no delay extent in this tree */
3847         else if (es.es_lblk <= lblk_start &&
3848                  lblk_start < es.es_lblk + es.es_len)
3849                 return 1;
3850         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3851                 return 1;
3852         else
3853                 return 0;
3854 }
3855
3856 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3857 {
3858         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3859         ext4_lblk_t lblk_start, lblk_end;
3860         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3861         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3862
3863         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3864 }
3865
3866 /**
3867  * Determines how many complete clusters (out of those specified by the 'map')
3868  * are under delalloc and were reserved quota for.
3869  * This function is called when we are writing out the blocks that were
3870  * originally written with their allocation delayed, but then the space was
3871  * allocated using fallocate() before the delayed allocation could be resolved.
3872  * The cases to look for are:
3873  * ('=' indicated delayed allocated blocks
3874  *  '-' indicates non-delayed allocated blocks)
3875  * (a) partial clusters towards beginning and/or end outside of allocated range
3876  *     are not delalloc'ed.
3877  *      Ex:
3878  *      |----c---=|====c====|====c====|===-c----|
3879  *               |++++++ allocated ++++++|
3880  *      ==> 4 complete clusters in above example
3881  *
3882  * (b) partial cluster (outside of allocated range) towards either end is
3883  *     marked for delayed allocation. In this case, we will exclude that
3884  *     cluster.
3885  *      Ex:
3886  *      |----====c========|========c========|
3887  *           |++++++ allocated ++++++|
3888  *      ==> 1 complete clusters in above example
3889  *
3890  *      Ex:
3891  *      |================c================|
3892  *            |++++++ allocated ++++++|
3893  *      ==> 0 complete clusters in above example
3894  *
3895  * The ext4_da_update_reserve_space will be called only if we
3896  * determine here that there were some "entire" clusters that span
3897  * this 'allocated' range.
3898  * In the non-bigalloc case, this function will just end up returning num_blks
3899  * without ever calling ext4_find_delalloc_range.
3900  */
3901 static unsigned int
3902 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3903                            unsigned int num_blks)
3904 {
3905         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3906         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3907         ext4_lblk_t lblk_from, lblk_to, c_offset;
3908         unsigned int allocated_clusters = 0;
3909
3910         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3911         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3912
3913         /* max possible clusters for this allocation */
3914         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3915
3916         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3917
3918         /* Check towards left side */
3919         c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3920         if (c_offset) {
3921                 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3922                 lblk_to = lblk_from + c_offset - 1;
3923
3924                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3925                         allocated_clusters--;
3926         }
3927
3928         /* Now check towards right. */
3929         c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3930         if (allocated_clusters && c_offset) {
3931                 lblk_from = lblk_start + num_blks;
3932                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3933
3934                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3935                         allocated_clusters--;
3936         }
3937
3938         return allocated_clusters;
3939 }
3940
3941 static int
3942 convert_initialized_extent(handle_t *handle, struct inode *inode,
3943                            struct ext4_map_blocks *map,
3944                            struct ext4_ext_path **ppath,
3945                            unsigned int allocated)
3946 {
3947         struct ext4_ext_path *path = *ppath;
3948         struct ext4_extent *ex;
3949         ext4_lblk_t ee_block;
3950         unsigned int ee_len;
3951         int depth;
3952         int err = 0;
3953
3954         /*
3955          * Make sure that the extent is no bigger than we support with
3956          * unwritten extent
3957          */
3958         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3959                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3960
3961         depth = ext_depth(inode);
3962         ex = path[depth].p_ext;
3963         ee_block = le32_to_cpu(ex->ee_block);
3964         ee_len = ext4_ext_get_actual_len(ex);
3965
3966         ext_debug("%s: inode %lu, logical"
3967                 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3968                   (unsigned long long)ee_block, ee_len);
3969
3970         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3971                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3972                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3973                 if (err < 0)
3974                         return err;
3975                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3976                 if (IS_ERR(path))
3977                         return PTR_ERR(path);
3978                 depth = ext_depth(inode);
3979                 ex = path[depth].p_ext;
3980                 if (!ex) {
3981                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3982                                          (unsigned long) map->m_lblk);
3983                         return -EFSCORRUPTED;
3984                 }
3985         }
3986
3987         err = ext4_ext_get_access(handle, inode, path + depth);
3988         if (err)
3989                 return err;
3990         /* first mark the extent as unwritten */
3991         ext4_ext_mark_unwritten(ex);
3992
3993         /* note: ext4_ext_correct_indexes() isn't needed here because
3994          * borders are not changed
3995          */
3996         ext4_ext_try_to_merge(handle, inode, path, ex);
3997
3998         /* Mark modified extent as dirty */
3999         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
4000         if (err)
4001                 return err;
4002         ext4_ext_show_leaf(inode, path);
4003
4004         ext4_update_inode_fsync_trans(handle, inode, 1);
4005         err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
4006         if (err)
4007                 return err;
4008         map->m_flags |= EXT4_MAP_UNWRITTEN;
4009         if (allocated > map->m_len)
4010                 allocated = map->m_len;
4011         map->m_len = allocated;
4012         return allocated;
4013 }
4014
4015 static int
4016 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4017                         struct ext4_map_blocks *map,
4018                         struct ext4_ext_path **ppath, int flags,
4019                         unsigned int allocated, ext4_fsblk_t newblock)
4020 {
4021         struct ext4_ext_path *path = *ppath;
4022         int ret = 0;
4023         int err = 0;
4024
4025         ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4026                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
4027                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4028                   flags, allocated);
4029         ext4_ext_show_leaf(inode, path);
4030
4031         /*
4032          * When writing into unwritten space, we should not fail to
4033          * allocate metadata blocks for the new extent block if needed.
4034          */
4035         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4036
4037         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4038                                                     allocated, newblock);
4039
4040         /* get_block() before submit the IO, split the extent */
4041         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4042                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4043                                          flags | EXT4_GET_BLOCKS_CONVERT);
4044                 if (ret <= 0)
4045                         goto out;
4046                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4047                 goto out;
4048         }
4049         /* IO end_io complete, convert the filled extent to written */
4050         if (flags & EXT4_GET_BLOCKS_CONVERT) {
4051                 if (flags & EXT4_GET_BLOCKS_ZERO) {
4052                         if (allocated > map->m_len)
4053                                 allocated = map->m_len;
4054                         err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4055                                                  allocated);
4056                         if (err < 0)
4057                                 goto out2;
4058                 }
4059                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4060                                                            ppath);
4061                 if (ret >= 0) {
4062                         ext4_update_inode_fsync_trans(handle, inode, 1);
4063                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
4064                                                  path, map->m_len);
4065                 } else
4066                         err = ret;
4067                 map->m_flags |= EXT4_MAP_MAPPED;
4068                 map->m_pblk = newblock;
4069                 if (allocated > map->m_len)
4070                         allocated = map->m_len;
4071                 map->m_len = allocated;
4072                 goto out2;
4073         }
4074         /* buffered IO case */
4075         /*
4076          * repeat fallocate creation request
4077          * we already have an unwritten extent
4078          */
4079         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4080                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4081                 goto map_out;
4082         }
4083
4084         /* buffered READ or buffered write_begin() lookup */
4085         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4086                 /*
4087                  * We have blocks reserved already.  We
4088                  * return allocated blocks so that delalloc
4089                  * won't do block reservation for us.  But
4090                  * the buffer head will be unmapped so that
4091                  * a read from the block returns 0s.
4092                  */
4093                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4094                 goto out1;
4095         }
4096
4097         /* buffered write, writepage time, convert*/
4098         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4099         if (ret >= 0)
4100                 ext4_update_inode_fsync_trans(handle, inode, 1);
4101 out:
4102         if (ret <= 0) {
4103                 err = ret;
4104                 goto out2;
4105         } else
4106                 allocated = ret;
4107         map->m_flags |= EXT4_MAP_NEW;
4108         /*
4109          * if we allocated more blocks than requested
4110          * we need to make sure we unmap the extra block
4111          * allocated. The actual needed block will get
4112          * unmapped later when we find the buffer_head marked
4113          * new.
4114          */
4115         if (allocated > map->m_len) {
4116                 clean_bdev_aliases(inode->i_sb->s_bdev, newblock + map->m_len,
4117                                    allocated - map->m_len);
4118                 allocated = map->m_len;
4119         }
4120         map->m_len = allocated;
4121
4122         /*
4123          * If we have done fallocate with the offset that is already
4124          * delayed allocated, we would have block reservation
4125          * and quota reservation done in the delayed write path.
4126          * But fallocate would have already updated quota and block
4127          * count for this offset. So cancel these reservation
4128          */
4129         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4130                 unsigned int reserved_clusters;
4131                 reserved_clusters = get_reserved_cluster_alloc(inode,
4132                                 map->m_lblk, map->m_len);
4133                 if (reserved_clusters)
4134                         ext4_da_update_reserve_space(inode,
4135                                                      reserved_clusters,
4136                                                      0);
4137         }
4138
4139 map_out:
4140         map->m_flags |= EXT4_MAP_MAPPED;
4141         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4142                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4143                                          map->m_len);
4144                 if (err < 0)
4145                         goto out2;
4146         }
4147 out1:
4148         if (allocated > map->m_len)
4149                 allocated = map->m_len;
4150         ext4_ext_show_leaf(inode, path);
4151         map->m_pblk = newblock;
4152         map->m_len = allocated;
4153 out2:
4154         return err ? err : allocated;
4155 }
4156
4157 /*
4158  * get_implied_cluster_alloc - check to see if the requested
4159  * allocation (in the map structure) overlaps with a cluster already
4160  * allocated in an extent.
4161  *      @sb     The filesystem superblock structure
4162  *      @map    The requested lblk->pblk mapping
4163  *      @ex     The extent structure which might contain an implied
4164  *                      cluster allocation
4165  *
4166  * This function is called by ext4_ext_map_blocks() after we failed to
4167  * find blocks that were already in the inode's extent tree.  Hence,
4168  * we know that the beginning of the requested region cannot overlap
4169  * the extent from the inode's extent tree.  There are three cases we
4170  * want to catch.  The first is this case:
4171  *
4172  *               |--- cluster # N--|
4173  *    |--- extent ---|  |---- requested region ---|
4174  *                      |==========|
4175  *
4176  * The second case that we need to test for is this one:
4177  *
4178  *   |--------- cluster # N ----------------|
4179  *         |--- requested region --|   |------- extent ----|
4180  *         |=======================|
4181  *
4182  * The third case is when the requested region lies between two extents
4183  * within the same cluster:
4184  *          |------------- cluster # N-------------|
4185  * |----- ex -----|                  |---- ex_right ----|
4186  *                  |------ requested region ------|
4187  *                  |================|
4188  *
4189  * In each of the above cases, we need to set the map->m_pblk and
4190  * map->m_len so it corresponds to the return the extent labelled as
4191  * "|====|" from cluster #N, since it is already in use for data in
4192  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4193  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4194  * as a new "allocated" block region.  Otherwise, we will return 0 and
4195  * ext4_ext_map_blocks() will then allocate one or more new clusters
4196  * by calling ext4_mb_new_blocks().
4197  */
4198 static int get_implied_cluster_alloc(struct super_block *sb,
4199                                      struct ext4_map_blocks *map,
4200                                      struct ext4_extent *ex,
4201                                      struct ext4_ext_path *path)
4202 {
4203         struct ext4_sb_info *sbi = EXT4_SB(sb);
4204         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4205         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4206         ext4_lblk_t rr_cluster_start;
4207         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4208         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4209         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4210
4211         /* The extent passed in that we are trying to match */
4212         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4213         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4214
4215         /* The requested region passed into ext4_map_blocks() */
4216         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4217
4218         if ((rr_cluster_start == ex_cluster_end) ||
4219             (rr_cluster_start == ex_cluster_start)) {
4220                 if (rr_cluster_start == ex_cluster_end)
4221                         ee_start += ee_len - 1;
4222                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4223                 map->m_len = min(map->m_len,
4224                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4225                 /*
4226                  * Check for and handle this case:
4227                  *
4228                  *   |--------- cluster # N-------------|
4229                  *                     |------- extent ----|
4230                  *         |--- requested region ---|
4231                  *         |===========|
4232                  */
4233
4234                 if (map->m_lblk < ee_block)
4235                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4236
4237                 /*
4238                  * Check for the case where there is already another allocated
4239                  * block to the right of 'ex' but before the end of the cluster.
4240                  *
4241                  *          |------------- cluster # N-------------|
4242                  * |----- ex -----|                  |---- ex_right ----|
4243                  *                  |------ requested region ------|
4244                  *                  |================|
4245                  */
4246                 if (map->m_lblk > ee_block) {
4247                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4248                         map->m_len = min(map->m_len, next - map->m_lblk);
4249                 }
4250
4251                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4252                 return 1;
4253         }
4254
4255         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4256         return 0;
4257 }
4258
4259
4260 /*
4261  * Block allocation/map/preallocation routine for extents based files
4262  *
4263  *
4264  * Need to be called with
4265  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4266  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4267  *
4268  * return > 0, number of of blocks already mapped/allocated
4269  *          if create == 0 and these are pre-allocated blocks
4270  *              buffer head is unmapped
4271  *          otherwise blocks are mapped
4272  *
4273  * return = 0, if plain look up failed (blocks have not been allocated)
4274  *          buffer head is unmapped
4275  *
4276  * return < 0, error case.
4277  */
4278 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4279                         struct ext4_map_blocks *map, int flags)
4280 {
4281         struct ext4_ext_path *path = NULL;
4282         struct ext4_extent newex, *ex, *ex2;
4283         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4284         ext4_fsblk_t newblock = 0;
4285         int free_on_err = 0, err = 0, depth, ret;
4286         unsigned int allocated = 0, offset = 0;
4287         unsigned int allocated_clusters = 0;
4288         struct ext4_allocation_request ar;
4289         ext4_lblk_t cluster_offset;
4290         bool map_from_cluster = false;
4291
4292         ext_debug("blocks %u/%u requested for inode %lu\n",
4293                   map->m_lblk, map->m_len, inode->i_ino);
4294         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4295
4296         /* find extent for this block */
4297         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4298         if (IS_ERR(path)) {
4299                 err = PTR_ERR(path);
4300                 path = NULL;
4301                 goto out2;
4302         }
4303
4304         depth = ext_depth(inode);
4305
4306         /*
4307          * consistent leaf must not be empty;
4308          * this situation is possible, though, _during_ tree modification;
4309          * this is why assert can't be put in ext4_find_extent()
4310          */
4311         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4312                 EXT4_ERROR_INODE(inode, "bad extent address "
4313                                  "lblock: %lu, depth: %d pblock %lld",
4314                                  (unsigned long) map->m_lblk, depth,
4315                                  path[depth].p_block);
4316                 err = -EFSCORRUPTED;
4317                 goto out2;
4318         }
4319
4320         ex = path[depth].p_ext;
4321         if (ex) {
4322                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4323                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4324                 unsigned short ee_len;
4325
4326
4327                 /*
4328                  * unwritten extents are treated as holes, except that
4329                  * we split out initialized portions during a write.
4330                  */
4331                 ee_len = ext4_ext_get_actual_len(ex);
4332
4333                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4334
4335                 /* if found extent covers block, simply return it */
4336                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4337                         newblock = map->m_lblk - ee_block + ee_start;
4338                         /* number of remaining blocks in the extent */
4339                         allocated = ee_len - (map->m_lblk - ee_block);
4340                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4341                                   ee_block, ee_len, newblock);
4342
4343                         /*
4344                          * If the extent is initialized check whether the
4345                          * caller wants to convert it to unwritten.
4346                          */
4347                         if ((!ext4_ext_is_unwritten(ex)) &&
4348                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4349                                 allocated = convert_initialized_extent(
4350                                                 handle, inode, map, &path,
4351                                                 allocated);
4352                                 goto out2;
4353                         } else if (!ext4_ext_is_unwritten(ex))
4354                                 goto out;
4355
4356                         ret = ext4_ext_handle_unwritten_extents(
4357                                 handle, inode, map, &path, flags,
4358                                 allocated, newblock);
4359                         if (ret < 0)
4360                                 err = ret;
4361                         else
4362                                 allocated = ret;
4363                         goto out2;
4364                 }
4365         }
4366
4367         /*
4368          * requested block isn't allocated yet;
4369          * we couldn't try to create block if create flag is zero
4370          */
4371         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4372                 ext4_lblk_t hole_start, hole_len;
4373
4374                 hole_start = map->m_lblk;
4375                 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4376                 /*
4377                  * put just found gap into cache to speed up
4378                  * subsequent requests
4379                  */
4380                 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4381
4382                 /* Update hole_len to reflect hole size after map->m_lblk */
4383                 if (hole_start != map->m_lblk)
4384                         hole_len -= map->m_lblk - hole_start;
4385                 map->m_pblk = 0;
4386                 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4387
4388                 goto out2;
4389         }
4390
4391         /*
4392          * Okay, we need to do block allocation.
4393          */
4394         newex.ee_block = cpu_to_le32(map->m_lblk);
4395         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4396
4397         /*
4398          * If we are doing bigalloc, check to see if the extent returned
4399          * by ext4_find_extent() implies a cluster we can use.
4400          */
4401         if (cluster_offset && ex &&
4402             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4403                 ar.len = allocated = map->m_len;
4404                 newblock = map->m_pblk;
4405                 map_from_cluster = true;
4406                 goto got_allocated_blocks;
4407         }
4408
4409         /* find neighbour allocated blocks */
4410         ar.lleft = map->m_lblk;
4411         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4412         if (err)
4413                 goto out2;
4414         ar.lright = map->m_lblk;
4415         ex2 = NULL;
4416         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4417         if (err)
4418                 goto out2;
4419
4420         /* Check if the extent after searching to the right implies a
4421          * cluster we can use. */
4422         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4423             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4424                 ar.len = allocated = map->m_len;
4425                 newblock = map->m_pblk;
4426                 map_from_cluster = true;
4427                 goto got_allocated_blocks;
4428         }
4429
4430         /*
4431          * See if request is beyond maximum number of blocks we can have in
4432          * a single extent. For an initialized extent this limit is
4433          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4434          * EXT_UNWRITTEN_MAX_LEN.
4435          */
4436         if (map->m_len > EXT_INIT_MAX_LEN &&
4437             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4438                 map->m_len = EXT_INIT_MAX_LEN;
4439         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4440                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4441                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4442
4443         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4444         newex.ee_len = cpu_to_le16(map->m_len);
4445         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4446         if (err)
4447                 allocated = ext4_ext_get_actual_len(&newex);
4448         else
4449                 allocated = map->m_len;
4450
4451         /* allocate new block */
4452         ar.inode = inode;
4453         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4454         ar.logical = map->m_lblk;
4455         /*
4456          * We calculate the offset from the beginning of the cluster
4457          * for the logical block number, since when we allocate a
4458          * physical cluster, the physical block should start at the
4459          * same offset from the beginning of the cluster.  This is
4460          * needed so that future calls to get_implied_cluster_alloc()
4461          * work correctly.
4462          */
4463         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4464         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4465         ar.goal -= offset;
4466         ar.logical -= offset;
4467         if (S_ISREG(inode->i_mode))
4468                 ar.flags = EXT4_MB_HINT_DATA;
4469         else
4470                 /* disable in-core preallocation for non-regular files */
4471                 ar.flags = 0;
4472         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4473                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4474         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4475                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4476         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4477                 ar.flags |= EXT4_MB_USE_RESERVED;
4478         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4479         if (!newblock)
4480                 goto out2;
4481         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4482                   ar.goal, newblock, allocated);
4483         free_on_err = 1;
4484         allocated_clusters = ar.len;
4485         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4486         if (ar.len > allocated)
4487                 ar.len = allocated;
4488
4489 got_allocated_blocks:
4490         /* try to insert new extent into found leaf and return */
4491         ext4_ext_store_pblock(&newex, newblock + offset);
4492         newex.ee_len = cpu_to_le16(ar.len);
4493         /* Mark unwritten */
4494         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4495                 ext4_ext_mark_unwritten(&newex);
4496                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4497         }
4498
4499         err = 0;
4500         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4501                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4502                                          path, ar.len);
4503         if (!err)
4504                 err = ext4_ext_insert_extent(handle, inode, &path,
4505                                              &newex, flags);
4506
4507         if (err && free_on_err) {
4508                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4509                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4510                 /* free data blocks we just allocated */
4511                 /* not a good idea to call discard here directly,
4512                  * but otherwise we'd need to call it every free() */
4513                 ext4_discard_preallocations(inode);
4514                 ext4_free_blocks(handle, inode, NULL, newblock,
4515                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4516                 goto out2;
4517         }
4518
4519         /* previous routine could use block we allocated */
4520         newblock = ext4_ext_pblock(&newex);
4521         allocated = ext4_ext_get_actual_len(&newex);
4522         if (allocated > map->m_len)
4523                 allocated = map->m_len;
4524         map->m_flags |= EXT4_MAP_NEW;
4525
4526         /*
4527          * Update reserved blocks/metadata blocks after successful
4528          * block allocation which had been deferred till now.
4529          */
4530         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4531                 unsigned int reserved_clusters;
4532                 /*
4533                  * Check how many clusters we had reserved this allocated range
4534                  */
4535                 reserved_clusters = get_reserved_cluster_alloc(inode,
4536                                                 map->m_lblk, allocated);
4537                 if (!map_from_cluster) {
4538                         BUG_ON(allocated_clusters < reserved_clusters);
4539                         if (reserved_clusters < allocated_clusters) {
4540                                 struct ext4_inode_info *ei = EXT4_I(inode);
4541                                 int reservation = allocated_clusters -
4542                                                   reserved_clusters;
4543                                 /*
4544                                  * It seems we claimed few clusters outside of
4545                                  * the range of this allocation. We should give
4546                                  * it back to the reservation pool. This can
4547                                  * happen in the following case:
4548                                  *
4549                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4550                                  *   cluster has 4 blocks. Thus, the clusters
4551                                  *   are [0-3],[4-7],[8-11]...
4552                                  * * First comes delayed allocation write for
4553                                  *   logical blocks 10 & 11. Since there were no
4554                                  *   previous delayed allocated blocks in the
4555                                  *   range [8-11], we would reserve 1 cluster
4556                                  *   for this write.
4557                                  * * Next comes write for logical blocks 3 to 8.
4558                                  *   In this case, we will reserve 2 clusters
4559                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4560                                  *   that range has a delayed allocated blocks.
4561                                  *   Thus total reserved clusters now becomes 3.
4562                                  * * Now, during the delayed allocation writeout
4563                                  *   time, we will first write blocks [3-8] and
4564                                  *   allocate 3 clusters for writing these
4565                                  *   blocks. Also, we would claim all these
4566                                  *   three clusters above.
4567                                  * * Now when we come here to writeout the
4568                                  *   blocks [10-11], we would expect to claim
4569                                  *   the reservation of 1 cluster we had made
4570                                  *   (and we would claim it since there are no
4571                                  *   more delayed allocated blocks in the range
4572                                  *   [8-11]. But our reserved cluster count had
4573                                  *   already gone to 0.
4574                                  *
4575                                  *   Thus, at the step 4 above when we determine
4576                                  *   that there are still some unwritten delayed
4577                                  *   allocated blocks outside of our current
4578                                  *   block range, we should increment the
4579                                  *   reserved clusters count so that when the
4580                                  *   remaining blocks finally gets written, we
4581                                  *   could claim them.
4582                                  */
4583                                 dquot_reserve_block(inode,
4584                                                 EXT4_C2B(sbi, reservation));
4585                                 spin_lock(&ei->i_block_reservation_lock);
4586                                 ei->i_reserved_data_blocks += reservation;
4587                                 spin_unlock(&ei->i_block_reservation_lock);
4588                         }
4589                         /*
4590                          * We will claim quota for all newly allocated blocks.
4591                          * We're updating the reserved space *after* the
4592                          * correction above so we do not accidentally free
4593                          * all the metadata reservation because we might
4594                          * actually need it later on.
4595                          */
4596                         ext4_da_update_reserve_space(inode, allocated_clusters,
4597                                                         1);
4598                 }
4599         }
4600
4601         /*
4602          * Cache the extent and update transaction to commit on fdatasync only
4603          * when it is _not_ an unwritten extent.
4604          */
4605         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4606                 ext4_update_inode_fsync_trans(handle, inode, 1);
4607         else
4608                 ext4_update_inode_fsync_trans(handle, inode, 0);
4609 out:
4610         if (allocated > map->m_len)
4611                 allocated = map->m_len;
4612         ext4_ext_show_leaf(inode, path);
4613         map->m_flags |= EXT4_MAP_MAPPED;
4614         map->m_pblk = newblock;
4615         map->m_len = allocated;
4616 out2:
4617         ext4_ext_drop_refs(path);
4618         kfree(path);
4619
4620         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4621                                        err ? err : allocated);
4622         return err ? err : allocated;
4623 }
4624
4625 int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4626 {
4627         struct super_block *sb = inode->i_sb;
4628         ext4_lblk_t last_block;
4629         int err = 0;
4630
4631         /*
4632          * TODO: optimization is possible here.
4633          * Probably we need not scan at all,
4634          * because page truncation is enough.
4635          */
4636
4637         /* we have to know where to truncate from in crash case */
4638         EXT4_I(inode)->i_disksize = inode->i_size;
4639         err = ext4_mark_inode_dirty(handle, inode);
4640         if (err)
4641                 return err;
4642
4643         last_block = (inode->i_size + sb->s_blocksize - 1)
4644                         >> EXT4_BLOCK_SIZE_BITS(sb);
4645 retry:
4646         err = ext4_es_remove_extent(inode, last_block,
4647                                     EXT_MAX_BLOCKS - last_block);
4648         if (err == -ENOMEM) {
4649                 cond_resched();
4650                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4651                 goto retry;
4652         }
4653         if (err)
4654                 return err;
4655         return ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4656 }
4657
4658 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4659                                   ext4_lblk_t len, loff_t new_size,
4660                                   int flags, int mode)
4661 {
4662         struct inode *inode = file_inode(file);
4663         handle_t *handle;
4664         int ret = 0;
4665         int ret2 = 0;
4666         int retries = 0;
4667         int depth = 0;
4668         struct ext4_map_blocks map;
4669         unsigned int credits;
4670         loff_t epos;
4671
4672         BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4673         map.m_lblk = offset;
4674         map.m_len = len;
4675         /*
4676          * Don't normalize the request if it can fit in one extent so
4677          * that it doesn't get unnecessarily split into multiple
4678          * extents.
4679          */
4680         if (len <= EXT_UNWRITTEN_MAX_LEN)
4681                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4682
4683         /*
4684          * credits to insert 1 extent into extent tree
4685          */
4686         credits = ext4_chunk_trans_blocks(inode, len);
4687         depth = ext_depth(inode);
4688
4689 retry:
4690         while (ret >= 0 && len) {
4691                 /*
4692                  * Recalculate credits when extent tree depth changes.
4693                  */
4694                 if (depth != ext_depth(inode)) {
4695                         credits = ext4_chunk_trans_blocks(inode, len);
4696                         depth = ext_depth(inode);
4697                 }
4698
4699                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4700                                             credits);
4701                 if (IS_ERR(handle)) {
4702                         ret = PTR_ERR(handle);
4703                         break;
4704                 }
4705                 ret = ext4_map_blocks(handle, inode, &map, flags);
4706                 if (ret <= 0) {
4707                         ext4_debug("inode #%lu: block %u: len %u: "
4708                                    "ext4_ext_map_blocks returned %d",
4709                                    inode->i_ino, map.m_lblk,
4710                                    map.m_len, ret);
4711                         ext4_mark_inode_dirty(handle, inode);
4712                         ret2 = ext4_journal_stop(handle);
4713                         break;
4714                 }
4715                 map.m_lblk += ret;
4716                 map.m_len = len = len - ret;
4717                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4718                 inode->i_ctime = current_time(inode);
4719                 if (new_size) {
4720                         if (epos > new_size)
4721                                 epos = new_size;
4722                         if (ext4_update_inode_size(inode, epos) & 0x1)
4723                                 inode->i_mtime = inode->i_ctime;
4724                 } else {
4725                         if (epos > inode->i_size)
4726                                 ext4_set_inode_flag(inode,
4727                                                     EXT4_INODE_EOFBLOCKS);
4728                 }
4729                 ext4_mark_inode_dirty(handle, inode);
4730                 ret2 = ext4_journal_stop(handle);
4731                 if (ret2)
4732                         break;
4733         }
4734         if (ret == -ENOSPC &&
4735                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4736                 ret = 0;
4737                 goto retry;
4738         }
4739
4740         return ret > 0 ? ret2 : ret;
4741 }
4742
4743 static long ext4_zero_range(struct file *file, loff_t offset,
4744                             loff_t len, int mode)
4745 {
4746         struct inode *inode = file_inode(file);
4747         handle_t *handle = NULL;
4748         unsigned int max_blocks;
4749         loff_t new_size = 0;
4750         int ret = 0;
4751         int flags;
4752         int credits;
4753         int partial_begin, partial_end;
4754         loff_t start, end;
4755         ext4_lblk_t lblk;
4756         unsigned int blkbits = inode->i_blkbits;
4757
4758         trace_ext4_zero_range(inode, offset, len, mode);
4759
4760         if (!S_ISREG(inode->i_mode))
4761                 return -EINVAL;
4762
4763         /* Call ext4_force_commit to flush all data in case of data=journal. */
4764         if (ext4_should_journal_data(inode)) {
4765                 ret = ext4_force_commit(inode->i_sb);
4766                 if (ret)
4767                         return ret;
4768         }
4769
4770         /*
4771          * Round up offset. This is not fallocate, we neet to zero out
4772          * blocks, so convert interior block aligned part of the range to
4773          * unwritten and possibly manually zero out unaligned parts of the
4774          * range.
4775          */
4776         start = round_up(offset, 1 << blkbits);
4777         end = round_down((offset + len), 1 << blkbits);
4778
4779         if (start < offset || end > offset + len)
4780                 return -EINVAL;
4781         partial_begin = offset & ((1 << blkbits) - 1);
4782         partial_end = (offset + len) & ((1 << blkbits) - 1);
4783
4784         lblk = start >> blkbits;
4785         max_blocks = (end >> blkbits);
4786         if (max_blocks < lblk)
4787                 max_blocks = 0;
4788         else
4789                 max_blocks -= lblk;
4790
4791         inode_lock(inode);
4792
4793         /*
4794          * Indirect files do not support unwritten extnets
4795          */
4796         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4797                 ret = -EOPNOTSUPP;
4798                 goto out_mutex;
4799         }
4800
4801         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4802              offset + len > i_size_read(inode)) {
4803                 new_size = offset + len;
4804                 ret = inode_newsize_ok(inode, new_size);
4805                 if (ret)
4806                         goto out_mutex;
4807         }
4808
4809         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4810         if (mode & FALLOC_FL_KEEP_SIZE)
4811                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4812
4813         /* Wait all existing dio workers, newcomers will block on i_mutex */
4814         ext4_inode_block_unlocked_dio(inode);
4815         inode_dio_wait(inode);
4816
4817         /* Preallocate the range including the unaligned edges */
4818         if (partial_begin || partial_end) {
4819                 ret = ext4_alloc_file_blocks(file,
4820                                 round_down(offset, 1 << blkbits) >> blkbits,
4821                                 (round_up((offset + len), 1 << blkbits) -
4822                                  round_down(offset, 1 << blkbits)) >> blkbits,
4823                                 new_size, flags, mode);
4824                 if (ret)
4825                         goto out_dio;
4826
4827         }
4828
4829         /* Zero range excluding the unaligned edges */
4830         if (max_blocks > 0) {
4831                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4832                           EXT4_EX_NOCACHE);
4833
4834                 /*
4835                  * Prevent page faults from reinstantiating pages we have
4836                  * released from page cache.
4837                  */
4838                 down_write(&EXT4_I(inode)->i_mmap_sem);
4839                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4840                 if (ret) {
4841                         up_write(&EXT4_I(inode)->i_mmap_sem);
4842                         goto out_dio;
4843                 }
4844                 /* Now release the pages and zero block aligned part of pages */
4845                 truncate_pagecache_range(inode, start, end - 1);
4846                 inode->i_mtime = inode->i_ctime = current_time(inode);
4847
4848                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4849                                              flags, mode);
4850                 up_write(&EXT4_I(inode)->i_mmap_sem);
4851                 if (ret)
4852                         goto out_dio;
4853         }
4854         if (!partial_begin && !partial_end)
4855                 goto out_dio;
4856
4857         /*
4858          * In worst case we have to writeout two nonadjacent unwritten
4859          * blocks and update the inode
4860          */
4861         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4862         if (ext4_should_journal_data(inode))
4863                 credits += 2;
4864         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4865         if (IS_ERR(handle)) {
4866                 ret = PTR_ERR(handle);
4867                 ext4_std_error(inode->i_sb, ret);
4868                 goto out_dio;
4869         }
4870
4871         inode->i_mtime = inode->i_ctime = current_time(inode);
4872         if (new_size) {
4873                 ext4_update_inode_size(inode, new_size);
4874         } else {
4875                 /*
4876                 * Mark that we allocate beyond EOF so the subsequent truncate
4877                 * can proceed even if the new size is the same as i_size.
4878                 */
4879                 if ((offset + len) > i_size_read(inode))
4880                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4881         }
4882         ext4_mark_inode_dirty(handle, inode);
4883
4884         /* Zero out partial block at the edges of the range */
4885         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4886
4887         if (file->f_flags & O_SYNC)
4888                 ext4_handle_sync(handle);
4889
4890         ext4_journal_stop(handle);
4891 out_dio:
4892         ext4_inode_resume_unlocked_dio(inode);
4893 out_mutex:
4894         inode_unlock(inode);
4895         return ret;
4896 }
4897
4898 /*
4899  * preallocate space for a file. This implements ext4's fallocate file
4900  * operation, which gets called from sys_fallocate system call.
4901  * For block-mapped files, posix_fallocate should fall back to the method
4902  * of writing zeroes to the required new blocks (the same behavior which is
4903  * expected for file systems which do not support fallocate() system call).
4904  */
4905 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4906 {
4907         struct inode *inode = file_inode(file);
4908         loff_t new_size = 0;
4909         unsigned int max_blocks;
4910         int ret = 0;
4911         int flags;
4912         ext4_lblk_t lblk;
4913         unsigned int blkbits = inode->i_blkbits;
4914
4915         /*
4916          * Encrypted inodes can't handle collapse range or insert
4917          * range since we would need to re-encrypt blocks with a
4918          * different IV or XTS tweak (which are based on the logical
4919          * block number).
4920          *
4921          * XXX It's not clear why zero range isn't working, but we'll
4922          * leave it disabled for encrypted inodes for now.  This is a
4923          * bug we should fix....
4924          */
4925         if (ext4_encrypted_inode(inode) &&
4926             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4927                      FALLOC_FL_ZERO_RANGE)))
4928                 return -EOPNOTSUPP;
4929
4930         /* Return error if mode is not supported */
4931         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4932                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4933                      FALLOC_FL_INSERT_RANGE))
4934                 return -EOPNOTSUPP;
4935
4936         if (mode & FALLOC_FL_PUNCH_HOLE)
4937                 return ext4_punch_hole(inode, offset, len);
4938
4939         ret = ext4_convert_inline_data(inode);
4940         if (ret)
4941                 return ret;
4942
4943         if (mode & FALLOC_FL_COLLAPSE_RANGE)
4944                 return ext4_collapse_range(inode, offset, len);
4945
4946         if (mode & FALLOC_FL_INSERT_RANGE)
4947                 return ext4_insert_range(inode, offset, len);
4948
4949         if (mode & FALLOC_FL_ZERO_RANGE)
4950                 return ext4_zero_range(file, offset, len, mode);
4951
4952         trace_ext4_fallocate_enter(inode, offset, len, mode);
4953         lblk = offset >> blkbits;
4954
4955         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4956         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4957         if (mode & FALLOC_FL_KEEP_SIZE)
4958                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4959
4960         inode_lock(inode);
4961
4962         /*
4963          * We only support preallocation for extent-based files only
4964          */
4965         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4966                 ret = -EOPNOTSUPP;
4967                 goto out;
4968         }
4969
4970         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4971              offset + len > i_size_read(inode)) {
4972                 new_size = offset + len;
4973                 ret = inode_newsize_ok(inode, new_size);
4974                 if (ret)
4975                         goto out;
4976         }
4977
4978         /* Wait all existing dio workers, newcomers will block on i_mutex */
4979         ext4_inode_block_unlocked_dio(inode);
4980         inode_dio_wait(inode);
4981
4982         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4983                                      flags, mode);
4984         ext4_inode_resume_unlocked_dio(inode);
4985         if (ret)
4986                 goto out;
4987
4988         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4989                 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
4990                                                 EXT4_I(inode)->i_sync_tid);
4991         }
4992 out:
4993         inode_unlock(inode);
4994         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4995         return ret;
4996 }
4997
4998 /*
4999  * This function convert a range of blocks to written extents
5000  * The caller of this function will pass the start offset and the size.
5001  * all unwritten extents within this range will be converted to
5002  * written extents.
5003  *
5004  * This function is called from the direct IO end io call back
5005  * function, to convert the fallocated extents after IO is completed.
5006  * Returns 0 on success.
5007  */
5008 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
5009                                    loff_t offset, ssize_t len)
5010 {
5011         unsigned int max_blocks;
5012         int ret = 0;
5013         int ret2 = 0;
5014         struct ext4_map_blocks map;
5015         unsigned int credits, blkbits = inode->i_blkbits;
5016
5017         map.m_lblk = offset >> blkbits;
5018         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
5019
5020         /*
5021          * This is somewhat ugly but the idea is clear: When transaction is
5022          * reserved, everything goes into it. Otherwise we rather start several
5023          * smaller transactions for conversion of each extent separately.
5024          */
5025         if (handle) {
5026                 handle = ext4_journal_start_reserved(handle,
5027                                                      EXT4_HT_EXT_CONVERT);
5028                 if (IS_ERR(handle))
5029                         return PTR_ERR(handle);
5030                 credits = 0;
5031         } else {
5032                 /*
5033                  * credits to insert 1 extent into extent tree
5034                  */
5035                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5036         }
5037         while (ret >= 0 && ret < max_blocks) {
5038                 map.m_lblk += ret;
5039                 map.m_len = (max_blocks -= ret);
5040                 if (credits) {
5041                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5042                                                     credits);
5043                         if (IS_ERR(handle)) {
5044                                 ret = PTR_ERR(handle);
5045                                 break;
5046                         }
5047                 }
5048                 ret = ext4_map_blocks(handle, inode, &map,
5049                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5050                 if (ret <= 0)
5051                         ext4_warning(inode->i_sb,
5052                                      "inode #%lu: block %u: len %u: "
5053                                      "ext4_ext_map_blocks returned %d",
5054                                      inode->i_ino, map.m_lblk,
5055                                      map.m_len, ret);
5056                 ext4_mark_inode_dirty(handle, inode);
5057                 if (credits)
5058                         ret2 = ext4_journal_stop(handle);
5059                 if (ret <= 0 || ret2)
5060                         break;
5061         }
5062         if (!credits)
5063                 ret2 = ext4_journal_stop(handle);
5064         return ret > 0 ? ret2 : ret;
5065 }
5066
5067 /*
5068  * If newes is not existing extent (newes->ec_pblk equals zero) find
5069  * delayed extent at start of newes and update newes accordingly and
5070  * return start of the next delayed extent.
5071  *
5072  * If newes is existing extent (newes->ec_pblk is not equal zero)
5073  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5074  * extent found. Leave newes unmodified.
5075  */
5076 static int ext4_find_delayed_extent(struct inode *inode,
5077                                     struct extent_status *newes)
5078 {
5079         struct extent_status es;
5080         ext4_lblk_t block, next_del;
5081
5082         if (newes->es_pblk == 0) {
5083                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5084                                 newes->es_lblk + newes->es_len - 1, &es);
5085
5086                 /*
5087                  * No extent in extent-tree contains block @newes->es_pblk,
5088                  * then the block may stay in 1)a hole or 2)delayed-extent.
5089                  */
5090                 if (es.es_len == 0)
5091                         /* A hole found. */
5092                         return 0;
5093
5094                 if (es.es_lblk > newes->es_lblk) {
5095                         /* A hole found. */
5096                         newes->es_len = min(es.es_lblk - newes->es_lblk,
5097                                             newes->es_len);
5098                         return 0;
5099                 }
5100
5101                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5102         }
5103
5104         block = newes->es_lblk + newes->es_len;
5105         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5106         if (es.es_len == 0)
5107                 next_del = EXT_MAX_BLOCKS;
5108         else
5109                 next_del = es.es_lblk;
5110
5111         return next_del;
5112 }
5113 /* fiemap flags we can handle specified here */
5114 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5115
5116 static int ext4_xattr_fiemap(struct inode *inode,
5117                                 struct fiemap_extent_info *fieinfo)
5118 {
5119         __u64 physical = 0;
5120         __u64 length;
5121         __u32 flags = FIEMAP_EXTENT_LAST;
5122         int blockbits = inode->i_sb->s_blocksize_bits;
5123         int error = 0;
5124
5125         /* in-inode? */
5126         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5127                 struct ext4_iloc iloc;
5128                 int offset;     /* offset of xattr in inode */
5129
5130                 error = ext4_get_inode_loc(inode, &iloc);
5131                 if (error)
5132                         return error;
5133                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5134                 offset = EXT4_GOOD_OLD_INODE_SIZE +
5135                                 EXT4_I(inode)->i_extra_isize;
5136                 physical += offset;
5137                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5138                 flags |= FIEMAP_EXTENT_DATA_INLINE;
5139                 brelse(iloc.bh);
5140         } else { /* external block */
5141                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5142                 length = inode->i_sb->s_blocksize;
5143         }
5144
5145         if (physical)
5146                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5147                                                 length, flags);
5148         return (error < 0 ? error : 0);
5149 }
5150
5151 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5152                 __u64 start, __u64 len)
5153 {
5154         ext4_lblk_t start_blk;
5155         int error = 0;
5156
5157         if (ext4_has_inline_data(inode)) {
5158                 int has_inline = 1;
5159
5160                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5161                                                 start, len);
5162
5163                 if (has_inline)
5164                         return error;
5165         }
5166
5167         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5168                 error = ext4_ext_precache(inode);
5169                 if (error)
5170                         return error;
5171         }
5172
5173         /* fallback to generic here if not in extents fmt */
5174         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5175                 return generic_block_fiemap(inode, fieinfo, start, len,
5176                         ext4_get_block);
5177
5178         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5179                 return -EBADR;
5180
5181         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5182                 error = ext4_xattr_fiemap(inode, fieinfo);
5183         } else {
5184                 ext4_lblk_t len_blks;
5185                 __u64 last_blk;
5186
5187                 start_blk = start >> inode->i_sb->s_blocksize_bits;
5188                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5189                 if (last_blk >= EXT_MAX_BLOCKS)
5190                         last_blk = EXT_MAX_BLOCKS-1;
5191                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5192
5193                 /*
5194                  * Walk the extent tree gathering extent information
5195                  * and pushing extents back to the user.
5196                  */
5197                 error = ext4_fill_fiemap_extents(inode, start_blk,
5198                                                  len_blks, fieinfo);
5199         }
5200         return error;
5201 }
5202
5203 /*
5204  * ext4_access_path:
5205  * Function to access the path buffer for marking it dirty.
5206  * It also checks if there are sufficient credits left in the journal handle
5207  * to update path.
5208  */
5209 static int
5210 ext4_access_path(handle_t *handle, struct inode *inode,
5211                 struct ext4_ext_path *path)
5212 {
5213         int credits, err;
5214
5215         if (!ext4_handle_valid(handle))
5216                 return 0;
5217
5218         /*
5219          * Check if need to extend journal credits
5220          * 3 for leaf, sb, and inode plus 2 (bmap and group
5221          * descriptor) for each block group; assume two block
5222          * groups
5223          */
5224         if (handle->h_buffer_credits < 7) {
5225                 credits = ext4_writepage_trans_blocks(inode);
5226                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5227                 /* EAGAIN is success */
5228                 if (err && err != -EAGAIN)
5229                         return err;
5230         }
5231
5232         err = ext4_ext_get_access(handle, inode, path);
5233         return err;
5234 }
5235
5236 /*
5237  * ext4_ext_shift_path_extents:
5238  * Shift the extents of a path structure lying between path[depth].p_ext
5239  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5240  * if it is right shift or left shift operation.
5241  */
5242 static int
5243 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5244                             struct inode *inode, handle_t *handle,
5245                             enum SHIFT_DIRECTION SHIFT)
5246 {
5247         int depth, err = 0;
5248         struct ext4_extent *ex_start, *ex_last;
5249         bool update = 0;
5250         depth = path->p_depth;
5251
5252         while (depth >= 0) {
5253                 if (depth == path->p_depth) {
5254                         ex_start = path[depth].p_ext;
5255                         if (!ex_start)
5256                                 return -EFSCORRUPTED;
5257
5258                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5259
5260                         err = ext4_access_path(handle, inode, path + depth);
5261                         if (err)
5262                                 goto out;
5263
5264                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5265                                 update = 1;
5266
5267                         while (ex_start <= ex_last) {
5268                                 if (SHIFT == SHIFT_LEFT) {
5269                                         le32_add_cpu(&ex_start->ee_block,
5270                                                 -shift);
5271                                         /* Try to merge to the left. */
5272                                         if ((ex_start >
5273                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5274                                             &&
5275                                             ext4_ext_try_to_merge_right(inode,
5276                                             path, ex_start - 1))
5277                                                 ex_last--;
5278                                         else
5279                                                 ex_start++;
5280                                 } else {
5281                                         le32_add_cpu(&ex_last->ee_block, shift);
5282                                         ext4_ext_try_to_merge_right(inode, path,
5283                                                 ex_last);
5284                                         ex_last--;
5285                                 }
5286                         }
5287                         err = ext4_ext_dirty(handle, inode, path + depth);
5288                         if (err)
5289                                 goto out;
5290
5291                         if (--depth < 0 || !update)
5292                                 break;
5293                 }
5294
5295                 /* Update index too */
5296                 err = ext4_access_path(handle, inode, path + depth);
5297                 if (err)
5298                         goto out;
5299
5300                 if (SHIFT == SHIFT_LEFT)
5301                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5302                 else
5303                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5304                 err = ext4_ext_dirty(handle, inode, path + depth);
5305                 if (err)
5306                         goto out;
5307
5308                 /* we are done if current index is not a starting index */
5309                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5310                         break;
5311
5312                 depth--;
5313         }
5314
5315 out:
5316         return err;
5317 }
5318
5319 /*
5320  * ext4_ext_shift_extents:
5321  * All the extents which lies in the range from @start to the last allocated
5322  * block for the @inode are shifted either towards left or right (depending
5323  * upon @SHIFT) by @shift blocks.
5324  * On success, 0 is returned, error otherwise.
5325  */
5326 static int
5327 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5328                        ext4_lblk_t start, ext4_lblk_t shift,
5329                        enum SHIFT_DIRECTION SHIFT)
5330 {
5331         struct ext4_ext_path *path;
5332         int ret = 0, depth;
5333         struct ext4_extent *extent;
5334         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5335
5336         /* Let path point to the last extent */
5337         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5338                                 EXT4_EX_NOCACHE);
5339         if (IS_ERR(path))
5340                 return PTR_ERR(path);
5341
5342         depth = path->p_depth;
5343         extent = path[depth].p_ext;
5344         if (!extent)
5345                 goto out;
5346
5347         stop = le32_to_cpu(extent->ee_block);
5348
5349        /*
5350          * In case of left shift, Don't start shifting extents until we make
5351          * sure the hole is big enough to accommodate the shift.
5352         */
5353         if (SHIFT == SHIFT_LEFT) {
5354                 path = ext4_find_extent(inode, start - 1, &path,
5355                                         EXT4_EX_NOCACHE);
5356                 if (IS_ERR(path))
5357                         return PTR_ERR(path);
5358                 depth = path->p_depth;
5359                 extent =  path[depth].p_ext;
5360                 if (extent) {
5361                         ex_start = le32_to_cpu(extent->ee_block);
5362                         ex_end = le32_to_cpu(extent->ee_block) +
5363                                 ext4_ext_get_actual_len(extent);
5364                 } else {
5365                         ex_start = 0;
5366                         ex_end = 0;
5367                 }
5368
5369                 if ((start == ex_start && shift > ex_start) ||
5370                     (shift > start - ex_end)) {
5371                         ext4_ext_drop_refs(path);
5372                         kfree(path);
5373                         return -EINVAL;
5374                 }
5375         }
5376
5377         /*
5378          * In case of left shift, iterator points to start and it is increased
5379          * till we reach stop. In case of right shift, iterator points to stop
5380          * and it is decreased till we reach start.
5381          */
5382         if (SHIFT == SHIFT_LEFT)
5383                 iterator = &start;
5384         else
5385                 iterator = &stop;
5386
5387         /*
5388          * Its safe to start updating extents.  Start and stop are unsigned, so
5389          * in case of right shift if extent with 0 block is reached, iterator
5390          * becomes NULL to indicate the end of the loop.
5391          */
5392         while (iterator && start <= stop) {
5393                 path = ext4_find_extent(inode, *iterator, &path,
5394                                         EXT4_EX_NOCACHE);
5395                 if (IS_ERR(path))
5396                         return PTR_ERR(path);
5397                 depth = path->p_depth;
5398                 extent = path[depth].p_ext;
5399                 if (!extent) {
5400                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5401                                          (unsigned long) *iterator);
5402                         return -EFSCORRUPTED;
5403                 }
5404                 if (SHIFT == SHIFT_LEFT && *iterator >
5405                     le32_to_cpu(extent->ee_block)) {
5406                         /* Hole, move to the next extent */
5407                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5408                                 path[depth].p_ext++;
5409                         } else {
5410                                 *iterator = ext4_ext_next_allocated_block(path);
5411                                 continue;
5412                         }
5413                 }
5414
5415                 if (SHIFT == SHIFT_LEFT) {
5416                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5417                         *iterator = le32_to_cpu(extent->ee_block) +
5418                                         ext4_ext_get_actual_len(extent);
5419                 } else {
5420                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5421                         if (le32_to_cpu(extent->ee_block) > 0)
5422                                 *iterator = le32_to_cpu(extent->ee_block) - 1;
5423                         else
5424                                 /* Beginning is reached, end of the loop */
5425                                 iterator = NULL;
5426                         /* Update path extent in case we need to stop */
5427                         while (le32_to_cpu(extent->ee_block) < start)
5428                                 extent++;
5429                         path[depth].p_ext = extent;
5430                 }
5431                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5432                                 handle, SHIFT);
5433                 if (ret)
5434                         break;
5435         }
5436 out:
5437         ext4_ext_drop_refs(path);
5438         kfree(path);
5439         return ret;
5440 }
5441
5442 /*
5443  * ext4_collapse_range:
5444  * This implements the fallocate's collapse range functionality for ext4
5445  * Returns: 0 and non-zero on error.
5446  */
5447 int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5448 {
5449         struct super_block *sb = inode->i_sb;
5450         ext4_lblk_t punch_start, punch_stop;
5451         handle_t *handle;
5452         unsigned int credits;
5453         loff_t new_size, ioffset;
5454         int ret;
5455
5456         /*
5457          * We need to test this early because xfstests assumes that a
5458          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5459          * system does not support collapse range.
5460          */
5461         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5462                 return -EOPNOTSUPP;
5463
5464         /* Collapse range works only on fs block size aligned offsets. */
5465         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5466             len & (EXT4_CLUSTER_SIZE(sb) - 1))
5467                 return -EINVAL;
5468
5469         if (!S_ISREG(inode->i_mode))
5470                 return -EINVAL;
5471
5472         trace_ext4_collapse_range(inode, offset, len);
5473
5474         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5475         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5476
5477         /* Call ext4_force_commit to flush all data in case of data=journal. */
5478         if (ext4_should_journal_data(inode)) {
5479                 ret = ext4_force_commit(inode->i_sb);
5480                 if (ret)
5481                         return ret;
5482         }
5483
5484         inode_lock(inode);
5485         /*
5486          * There is no need to overlap collapse range with EOF, in which case
5487          * it is effectively a truncate operation
5488          */
5489         if (offset + len >= i_size_read(inode)) {
5490                 ret = -EINVAL;
5491                 goto out_mutex;
5492         }
5493
5494         /* Currently just for extent based files */
5495         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5496                 ret = -EOPNOTSUPP;
5497                 goto out_mutex;
5498         }
5499
5500         /* Wait for existing dio to complete */
5501         ext4_inode_block_unlocked_dio(inode);
5502         inode_dio_wait(inode);
5503
5504         /*
5505          * Prevent page faults from reinstantiating pages we have released from
5506          * page cache.
5507          */
5508         down_write(&EXT4_I(inode)->i_mmap_sem);
5509         /*
5510          * Need to round down offset to be aligned with page size boundary
5511          * for page size > block size.
5512          */
5513         ioffset = round_down(offset, PAGE_SIZE);
5514         /*
5515          * Write tail of the last page before removed range since it will get
5516          * removed from the page cache below.
5517          */
5518         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5519         if (ret)
5520                 goto out_mmap;
5521         /*
5522          * Write data that will be shifted to preserve them when discarding
5523          * page cache below. We are also protected from pages becoming dirty
5524          * by i_mmap_sem.
5525          */
5526         ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5527                                            LLONG_MAX);
5528         if (ret)
5529                 goto out_mmap;
5530         truncate_pagecache(inode, ioffset);
5531
5532         credits = ext4_writepage_trans_blocks(inode);
5533         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5534         if (IS_ERR(handle)) {
5535                 ret = PTR_ERR(handle);
5536                 goto out_mmap;
5537         }
5538
5539         down_write(&EXT4_I(inode)->i_data_sem);
5540         ext4_discard_preallocations(inode);
5541
5542         ret = ext4_es_remove_extent(inode, punch_start,
5543                                     EXT_MAX_BLOCKS - punch_start);
5544         if (ret) {
5545                 up_write(&EXT4_I(inode)->i_data_sem);
5546                 goto out_stop;
5547         }
5548
5549         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5550         if (ret) {
5551                 up_write(&EXT4_I(inode)->i_data_sem);
5552                 goto out_stop;
5553         }
5554         ext4_discard_preallocations(inode);
5555
5556         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5557                                      punch_stop - punch_start, SHIFT_LEFT);
5558         if (ret) {
5559                 up_write(&EXT4_I(inode)->i_data_sem);
5560                 goto out_stop;
5561         }
5562
5563         new_size = i_size_read(inode) - len;
5564         i_size_write(inode, new_size);
5565         EXT4_I(inode)->i_disksize = new_size;
5566
5567         up_write(&EXT4_I(inode)->i_data_sem);
5568         if (IS_SYNC(inode))
5569                 ext4_handle_sync(handle);
5570         inode->i_mtime = inode->i_ctime = current_time(inode);
5571         ext4_mark_inode_dirty(handle, inode);
5572
5573 out_stop:
5574         ext4_journal_stop(handle);
5575 out_mmap:
5576         up_write(&EXT4_I(inode)->i_mmap_sem);
5577         ext4_inode_resume_unlocked_dio(inode);
5578 out_mutex:
5579         inode_unlock(inode);
5580         return ret;
5581 }
5582
5583 /*
5584  * ext4_insert_range:
5585  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5586  * The data blocks starting from @offset to the EOF are shifted by @len
5587  * towards right to create a hole in the @inode. Inode size is increased
5588  * by len bytes.
5589  * Returns 0 on success, error otherwise.
5590  */
5591 int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5592 {
5593         struct super_block *sb = inode->i_sb;
5594         handle_t *handle;
5595         struct ext4_ext_path *path;
5596         struct ext4_extent *extent;
5597         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5598         unsigned int credits, ee_len;
5599         int ret = 0, depth, split_flag = 0;
5600         loff_t ioffset;
5601
5602         /*
5603          * We need to test this early because xfstests assumes that an
5604          * insert range of (0, 1) will return EOPNOTSUPP if the file
5605          * system does not support insert range.
5606          */
5607         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5608                 return -EOPNOTSUPP;
5609
5610         /* Insert range works only on fs block size aligned offsets. */
5611         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5612                         len & (EXT4_CLUSTER_SIZE(sb) - 1))
5613                 return -EINVAL;
5614
5615         if (!S_ISREG(inode->i_mode))
5616                 return -EOPNOTSUPP;
5617
5618         trace_ext4_insert_range(inode, offset, len);
5619
5620         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5621         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5622
5623         /* Call ext4_force_commit to flush all data in case of data=journal */
5624         if (ext4_should_journal_data(inode)) {
5625                 ret = ext4_force_commit(inode->i_sb);
5626                 if (ret)
5627                         return ret;
5628         }
5629
5630         inode_lock(inode);
5631         /* Currently just for extent based files */
5632         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5633                 ret = -EOPNOTSUPP;
5634                 goto out_mutex;
5635         }
5636
5637         /* Check for wrap through zero */
5638         if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5639                 ret = -EFBIG;
5640                 goto out_mutex;
5641         }
5642
5643         /* Offset should be less than i_size */
5644         if (offset >= i_size_read(inode)) {
5645                 ret = -EINVAL;
5646                 goto out_mutex;
5647         }
5648
5649         /* Wait for existing dio to complete */
5650         ext4_inode_block_unlocked_dio(inode);
5651         inode_dio_wait(inode);
5652
5653         /*
5654          * Prevent page faults from reinstantiating pages we have released from
5655          * page cache.
5656          */
5657         down_write(&EXT4_I(inode)->i_mmap_sem);
5658         /*
5659          * Need to round down to align start offset to page size boundary
5660          * for page size > block size.
5661          */
5662         ioffset = round_down(offset, PAGE_SIZE);
5663         /* Write out all dirty pages */
5664         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5665                         LLONG_MAX);
5666         if (ret)
5667                 goto out_mmap;
5668         truncate_pagecache(inode, ioffset);
5669
5670         credits = ext4_writepage_trans_blocks(inode);
5671         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5672         if (IS_ERR(handle)) {
5673                 ret = PTR_ERR(handle);
5674                 goto out_mmap;
5675         }
5676
5677         /* Expand file to avoid data loss if there is error while shifting */
5678         inode->i_size += len;
5679         EXT4_I(inode)->i_disksize += len;
5680         inode->i_mtime = inode->i_ctime = current_time(inode);
5681         ret = ext4_mark_inode_dirty(handle, inode);
5682         if (ret)
5683                 goto out_stop;
5684
5685         down_write(&EXT4_I(inode)->i_data_sem);
5686         ext4_discard_preallocations(inode);
5687
5688         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5689         if (IS_ERR(path)) {
5690                 up_write(&EXT4_I(inode)->i_data_sem);
5691                 goto out_stop;
5692         }
5693
5694         depth = ext_depth(inode);
5695         extent = path[depth].p_ext;
5696         if (extent) {
5697                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5698                 ee_len = ext4_ext_get_actual_len(extent);
5699
5700                 /*
5701                  * If offset_lblk is not the starting block of extent, split
5702                  * the extent @offset_lblk
5703                  */
5704                 if ((offset_lblk > ee_start_lblk) &&
5705                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5706                         if (ext4_ext_is_unwritten(extent))
5707                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5708                                         EXT4_EXT_MARK_UNWRIT2;
5709                         ret = ext4_split_extent_at(handle, inode, &path,
5710                                         offset_lblk, split_flag,
5711                                         EXT4_EX_NOCACHE |
5712                                         EXT4_GET_BLOCKS_PRE_IO |
5713                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5714                 }
5715
5716                 ext4_ext_drop_refs(path);
5717                 kfree(path);
5718                 if (ret < 0) {
5719                         up_write(&EXT4_I(inode)->i_data_sem);
5720                         goto out_stop;
5721                 }
5722         } else {
5723                 ext4_ext_drop_refs(path);
5724                 kfree(path);
5725         }
5726
5727         ret = ext4_es_remove_extent(inode, offset_lblk,
5728                         EXT_MAX_BLOCKS - offset_lblk);
5729         if (ret) {
5730                 up_write(&EXT4_I(inode)->i_data_sem);
5731                 goto out_stop;
5732         }
5733
5734         /*
5735          * if offset_lblk lies in a hole which is at start of file, use
5736          * ee_start_lblk to shift extents
5737          */
5738         ret = ext4_ext_shift_extents(inode, handle,
5739                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5740                 len_lblk, SHIFT_RIGHT);
5741
5742         up_write(&EXT4_I(inode)->i_data_sem);
5743         if (IS_SYNC(inode))
5744                 ext4_handle_sync(handle);
5745
5746 out_stop:
5747         ext4_journal_stop(handle);
5748 out_mmap:
5749         up_write(&EXT4_I(inode)->i_mmap_sem);
5750         ext4_inode_resume_unlocked_dio(inode);
5751 out_mutex:
5752         inode_unlock(inode);
5753         return ret;
5754 }
5755
5756 /**
5757  * ext4_swap_extents - Swap extents between two inodes
5758  *
5759  * @inode1:     First inode
5760  * @inode2:     Second inode
5761  * @lblk1:      Start block for first inode
5762  * @lblk2:      Start block for second inode
5763  * @count:      Number of blocks to swap
5764  * @mark_unwritten: Mark second inode's extents as unwritten after swap
5765  * @erp:        Pointer to save error value
5766  *
5767  * This helper routine does exactly what is promise "swap extents". All other
5768  * stuff such as page-cache locking consistency, bh mapping consistency or
5769  * extent's data copying must be performed by caller.
5770  * Locking:
5771  *              i_mutex is held for both inodes
5772  *              i_data_sem is locked for write for both inodes
5773  * Assumptions:
5774  *              All pages from requested range are locked for both inodes
5775  */
5776 int
5777 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5778                      struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5779                   ext4_lblk_t count, int unwritten, int *erp)
5780 {
5781         struct ext4_ext_path *path1 = NULL;
5782         struct ext4_ext_path *path2 = NULL;
5783         int replaced_count = 0;
5784
5785         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5786         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5787         BUG_ON(!inode_is_locked(inode1));
5788         BUG_ON(!inode_is_locked(inode2));
5789
5790         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5791         if (unlikely(*erp))
5792                 return 0;
5793         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5794         if (unlikely(*erp))
5795                 return 0;
5796
5797         while (count) {
5798                 struct ext4_extent *ex1, *ex2, tmp_ex;
5799                 ext4_lblk_t e1_blk, e2_blk;
5800                 int e1_len, e2_len, len;
5801                 int split = 0;
5802
5803                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5804                 if (IS_ERR(path1)) {
5805                         *erp = PTR_ERR(path1);
5806                         path1 = NULL;
5807                 finish:
5808                         count = 0;
5809                         goto repeat;
5810                 }
5811                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5812                 if (IS_ERR(path2)) {
5813                         *erp = PTR_ERR(path2);
5814                         path2 = NULL;
5815                         goto finish;
5816                 }
5817                 ex1 = path1[path1->p_depth].p_ext;
5818                 ex2 = path2[path2->p_depth].p_ext;
5819                 /* Do we have somthing to swap ? */
5820                 if (unlikely(!ex2 || !ex1))
5821                         goto finish;
5822
5823                 e1_blk = le32_to_cpu(ex1->ee_block);
5824                 e2_blk = le32_to_cpu(ex2->ee_block);
5825                 e1_len = ext4_ext_get_actual_len(ex1);
5826                 e2_len = ext4_ext_get_actual_len(ex2);
5827
5828                 /* Hole handling */
5829                 if (!in_range(lblk1, e1_blk, e1_len) ||
5830                     !in_range(lblk2, e2_blk, e2_len)) {
5831                         ext4_lblk_t next1, next2;
5832
5833                         /* if hole after extent, then go to next extent */
5834                         next1 = ext4_ext_next_allocated_block(path1);
5835                         next2 = ext4_ext_next_allocated_block(path2);
5836                         /* If hole before extent, then shift to that extent */
5837                         if (e1_blk > lblk1)
5838                                 next1 = e1_blk;
5839                         if (e2_blk > lblk2)
5840                                 next2 = e1_blk;
5841                         /* Do we have something to swap */
5842                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5843                                 goto finish;
5844                         /* Move to the rightest boundary */
5845                         len = next1 - lblk1;
5846                         if (len < next2 - lblk2)
5847                                 len = next2 - lblk2;
5848                         if (len > count)
5849                                 len = count;
5850                         lblk1 += len;
5851                         lblk2 += len;
5852                         count -= len;
5853                         goto repeat;
5854                 }
5855
5856                 /* Prepare left boundary */
5857                 if (e1_blk < lblk1) {
5858                         split = 1;
5859                         *erp = ext4_force_split_extent_at(handle, inode1,
5860                                                 &path1, lblk1, 0);
5861                         if (unlikely(*erp))
5862                                 goto finish;
5863                 }
5864                 if (e2_blk < lblk2) {
5865                         split = 1;
5866                         *erp = ext4_force_split_extent_at(handle, inode2,
5867                                                 &path2,  lblk2, 0);
5868                         if (unlikely(*erp))
5869                                 goto finish;
5870                 }
5871                 /* ext4_split_extent_at() may result in leaf extent split,
5872                  * path must to be revalidated. */
5873                 if (split)
5874                         goto repeat;
5875
5876                 /* Prepare right boundary */
5877                 len = count;
5878                 if (len > e1_blk + e1_len - lblk1)
5879                         len = e1_blk + e1_len - lblk1;
5880                 if (len > e2_blk + e2_len - lblk2)
5881                         len = e2_blk + e2_len - lblk2;
5882
5883                 if (len != e1_len) {
5884                         split = 1;
5885                         *erp = ext4_force_split_extent_at(handle, inode1,
5886                                                 &path1, lblk1 + len, 0);
5887                         if (unlikely(*erp))
5888                                 goto finish;
5889                 }
5890                 if (len != e2_len) {
5891                         split = 1;
5892                         *erp = ext4_force_split_extent_at(handle, inode2,
5893                                                 &path2, lblk2 + len, 0);
5894                         if (*erp)
5895                                 goto finish;
5896                 }
5897                 /* ext4_split_extent_at() may result in leaf extent split,
5898                  * path must to be revalidated. */
5899                 if (split)
5900                         goto repeat;
5901
5902                 BUG_ON(e2_len != e1_len);
5903                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5904                 if (unlikely(*erp))
5905                         goto finish;
5906                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5907                 if (unlikely(*erp))
5908                         goto finish;
5909
5910                 /* Both extents are fully inside boundaries. Swap it now */
5911                 tmp_ex = *ex1;
5912                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5913                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5914                 ex1->ee_len = cpu_to_le16(e2_len);
5915                 ex2->ee_len = cpu_to_le16(e1_len);
5916                 if (unwritten)
5917                         ext4_ext_mark_unwritten(ex2);
5918                 if (ext4_ext_is_unwritten(&tmp_ex))
5919                         ext4_ext_mark_unwritten(ex1);
5920
5921                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5922                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5923                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5924                                       path2->p_depth);
5925                 if (unlikely(*erp))
5926                         goto finish;
5927                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5928                                       path1->p_depth);
5929                 /*
5930                  * Looks scarry ah..? second inode already points to new blocks,
5931                  * and it was successfully dirtied. But luckily error may happen
5932                  * only due to journal error, so full transaction will be
5933                  * aborted anyway.
5934                  */
5935                 if (unlikely(*erp))
5936                         goto finish;
5937                 lblk1 += len;
5938                 lblk2 += len;
5939                 replaced_count += len;
5940                 count -= len;
5941
5942         repeat:
5943                 ext4_ext_drop_refs(path1);
5944                 kfree(path1);
5945                 ext4_ext_drop_refs(path2);
5946                 kfree(path2);
5947                 path1 = path2 = NULL;
5948         }
5949         return replaced_count;
5950 }