fs/ext4/extents.c

   1 /*
   2  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3  * Written by Alex Tomas <alex@clusterfs.com>
   4  *
   5  * Architecture independence:
   6  *   Copyright (c) 2005, Bull S.A.
   7  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public Licens
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21  */
  22
  23 /*
  24  * Extents support for EXT4
  25  *
  26  * TODO:
  27  *   - ext4*_error() should be used in some situations
  28  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29  *   - smart tree reduction
  30  */
  31
  32 #include <linux/fs.h>
  33 #include <linux/time.h>
  34 #include <linux/jbd2.h>
  35 #include <linux/highuid.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/quotaops.h>
  38 #include <linux/string.h>
  39 #include <linux/slab.h>
  40 #include <asm/uaccess.h>
  41 #include <linux/fiemap.h>
  42 #include <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         err = ext4_journal_extend(handle, needed);
 126         if (err <= 0)
 127                 return err;
 128         err = ext4_truncate_restart_trans(handle, inode, needed);
 129         if (err == 0)
 130                 err = -EAGAIN;
 131
 132         return err;
 133 }
 134
 135 /*
 136  * could return:
 137  *  - EROFS
 138  *  - ENOMEM
 139  */
 140 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 141                                 struct ext4_ext_path *path)
 142 {
 143         if (path->p_bh) {
 144                 /* path points to block */
 145                 BUFFER_TRACE(path->p_bh, "get_write_access");
 146                 return ext4_journal_get_write_access(handle, path->p_bh);
 147         }
 148         /* path points to leaf/index in inode body */
 149         /* we use in-core data, no need to protect them */
 150         return 0;
 151 }
 152
 153 /*
 154  * could return:
 155  *  - EROFS
 156  *  - ENOMEM
 157  *  - EIO
 158  */
 159 int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 160                      struct inode *inode, struct ext4_ext_path *path)
 161 {
 162         int err;
 163
 164         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 165         if (path->p_bh) {
 166                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 167                 /* path points to block */
 168                 err = __ext4_handle_dirty_metadata(where, line, handle,
 169                                                    inode, path->p_bh);
 170         } else {
 171                 /* path points to leaf/index in inode body */
 172                 err = ext4_mark_inode_dirty(handle, inode);
 173         }
 174         return err;
 175 }
 176
 177 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 178                               struct ext4_ext_path *path,
 179                               ext4_lblk_t block)
 180 {
 181         if (path) {
 182                 int depth = path->p_depth;
 183                 struct ext4_extent *ex;
 184
 185                 /*
 186                  * Try to predict block placement assuming that we are
 187                  * filling in a file which will eventually be
 188                  * non-sparse --- i.e., in the case of libbfd writing
 189                  * an ELF object sections out-of-order but in a way
 190                  * the eventually results in a contiguous object or
 191                  * executable file, or some database extending a table
 192                  * space file.  However, this is actually somewhat
 193                  * non-ideal if we are writing a sparse file such as
 194                  * qemu or KVM writing a raw image file that is going
 195                  * to stay fairly sparse, since it will end up
 196                  * fragmenting the file system's free space.  Maybe we
 197                  * should have some hueristics or some way to allow
 198                  * userspace to pass a hint to file system,
 199                  * especially if the latter case turns out to be
 200                  * common.
 201                  */
 202                 ex = path[depth].p_ext;
 203                 if (ex) {
 204                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 205                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 206
 207                         if (block > ext_block)
 208                                 return ext_pblk + (block - ext_block);
 209                         else
 210                                 return ext_pblk - (ext_block - block);
 211                 }
 212
 213                 /* it looks like index is empty;
 214                  * try to find starting block from index itself */
 215                 if (path[depth].p_bh)
 216                         return path[depth].p_bh->b_blocknr;
 217         }
 218
 219         /* OK. use inode's group */
 220         return ext4_inode_to_goal_block(inode);
 221 }
 222
 223 /*
 224  * Allocation for a meta data block
 225  */
 226 static ext4_fsblk_t
 227 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 228                         struct ext4_ext_path *path,
 229                         struct ext4_extent *ex, int *err, unsigned int flags)
 230 {
 231         ext4_fsblk_t goal, newblock;
 232
 233         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 234         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 235                                         NULL, err);
 236         return newblock;
 237 }
 238
 239 static inline int ext4_ext_space_block(struct inode *inode, int check)
 240 {
 241         int size;
 242
 243         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 244                         / sizeof(struct ext4_extent);
 245 #ifdef AGGRESSIVE_TEST
 246         if (!check && size > 6)
 247                 size = 6;
 248 #endif
 249         return size;
 250 }
 251
 252 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 253 {
 254         int size;
 255
 256         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 257                         / sizeof(struct ext4_extent_idx);
 258 #ifdef AGGRESSIVE_TEST
 259         if (!check && size > 5)
 260                 size = 5;
 261 #endif
 262         return size;
 263 }
 264
 265 static inline int ext4_ext_space_root(struct inode *inode, int check)
 266 {
 267         int size;
 268
 269         size = sizeof(EXT4_I(inode)->i_data);
 270         size -= sizeof(struct ext4_extent_header);
 271         size /= sizeof(struct ext4_extent);
 272 #ifdef AGGRESSIVE_TEST
 273         if (!check && size > 3)
 274                 size = 3;
 275 #endif
 276         return size;
 277 }
 278
 279 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 280 {
 281         int size;
 282
 283         size = sizeof(EXT4_I(inode)->i_data);
 284         size -= sizeof(struct ext4_extent_header);
 285         size /= sizeof(struct ext4_extent_idx);
 286 #ifdef AGGRESSIVE_TEST
 287         if (!check && size > 4)
 288                 size = 4;
 289 #endif
 290         return size;
 291 }
 292
 293 static inline int
 294 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 295                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 296                            int nofail)
 297 {
 298         struct ext4_ext_path *path = *ppath;
 299         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 300
 301         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 302                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 303                         EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
 304                         (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
 305 }
 306
 307 /*
 308  * Calculate the number of metadata blocks needed
 309  * to allocate @blocks
 310  * Worse case is one block per extent
 311  */
 312 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 313 {
 314         struct ext4_inode_info *ei = EXT4_I(inode);
 315         int idxs;
 316
 317         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 318                 / sizeof(struct ext4_extent_idx));
 319
 320         /*
 321          * If the new delayed allocation block is contiguous with the
 322          * previous da block, it can share index blocks with the
 323          * previous block, so we only need to allocate a new index
 324          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 325          * an additional index block, and at ldxs**3 blocks, yet
 326          * another index blocks.
 327          */
 328         if (ei->i_da_metadata_calc_len &&
 329             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 330                 int num = 0;
 331
 332                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 333                         num++;
 334                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 335                         num++;
 336                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 337                         num++;
 338                         ei->i_da_metadata_calc_len = 0;
 339                 } else
 340                         ei->i_da_metadata_calc_len++;
 341                 ei->i_da_metadata_calc_last_lblock++;
 342                 return num;
 343         }
 344
 345         /*
 346          * In the worst case we need a new set of index blocks at
 347          * every level of the inode's extent tree.
 348          */
 349         ei->i_da_metadata_calc_len = 1;
 350         ei->i_da_metadata_calc_last_lblock = lblock;
 351         return ext_depth(inode) + 1;
 352 }
 353
 354 static int
 355 ext4_ext_max_entries(struct inode *inode, int depth)
 356 {
 357         int max;
 358
 359         if (depth == ext_depth(inode)) {
 360                 if (depth == 0)
 361                         max = ext4_ext_space_root(inode, 1);
 362                 else
 363                         max = ext4_ext_space_root_idx(inode, 1);
 364         } else {
 365                 if (depth == 0)
 366                         max = ext4_ext_space_block(inode, 1);
 367                 else
 368                         max = ext4_ext_space_block_idx(inode, 1);
 369         }
 370
 371         return max;
 372 }
 373
 374 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 375 {
 376         ext4_fsblk_t block = ext4_ext_pblock(ext);
 377         int len = ext4_ext_get_actual_len(ext);
 378         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 379         ext4_lblk_t last = lblock + len - 1;
 380
 381         if (len == 0 || lblock > last)
 382                 return 0;
 383         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 384 }
 385
 386 static int ext4_valid_extent_idx(struct inode *inode,
 387                                 struct ext4_extent_idx *ext_idx)
 388 {
 389         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 390
 391         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 392 }
 393
 394 static int ext4_valid_extent_entries(struct inode *inode,
 395                                 struct ext4_extent_header *eh,
 396                                 int depth)
 397 {
 398         unsigned short entries;
 399         if (eh->eh_entries == 0)
 400                 return 1;
 401
 402         entries = le16_to_cpu(eh->eh_entries);
 403
 404         if (depth == 0) {
 405                 /* leaf entries */
 406                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 407                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 408                 ext4_fsblk_t pblock = 0;
 409                 ext4_lblk_t lblock = 0;
 410                 ext4_lblk_t prev = 0;
 411                 int len = 0;
 412                 while (entries) {
 413                         if (!ext4_valid_extent(inode, ext))
 414                                 return 0;
 415
 416                         /* Check for overlapping extents */
 417                         lblock = le32_to_cpu(ext->ee_block);
 418                         len = ext4_ext_get_actual_len(ext);
 419                         if ((lblock <= prev) && prev) {
 420                                 pblock = ext4_ext_pblock(ext);
 421                                 es->s_last_error_block = cpu_to_le64(pblock);
 422                                 return 0;
 423                         }
 424                         ext++;
 425                         entries--;
 426                         prev = lblock + len - 1;
 427                 }
 428         } else {
 429                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 430                 while (entries) {
 431                         if (!ext4_valid_extent_idx(inode, ext_idx))
 432                                 return 0;
 433                         ext_idx++;
 434                         entries--;
 435                 }
 436         }
 437         return 1;
 438 }
 439
 440 static int __ext4_ext_check(const char *function, unsigned int line,
 441                             struct inode *inode, struct ext4_extent_header *eh,
 442                             int depth, ext4_fsblk_t pblk)
 443 {
 444         const char *error_msg;
 445         int max = 0, err = -EFSCORRUPTED;
 446
 447         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 448                 error_msg = "invalid magic";
 449                 goto corrupted;
 450         }
 451         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 452                 error_msg = "unexpected eh_depth";
 453                 goto corrupted;
 454         }
 455         if (unlikely(eh->eh_max == 0)) {
 456                 error_msg = "invalid eh_max";
 457                 goto corrupted;
 458         }
 459         max = ext4_ext_max_entries(inode, depth);
 460         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 461                 error_msg = "too large eh_max";
 462                 goto corrupted;
 463         }
 464         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 465                 error_msg = "invalid eh_entries";
 466                 goto corrupted;
 467         }
 468         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 469                 error_msg = "invalid extent entries";
 470                 goto corrupted;
 471         }
 472         if (unlikely(depth > 32)) {
 473                 error_msg = "too large eh_depth";
 474                 goto corrupted;
 475         }
 476         /* Verify checksum on non-root extent tree nodes */
 477         if (ext_depth(inode) != depth &&
 478             !ext4_extent_block_csum_verify(inode, eh)) {
 479                 error_msg = "extent tree corrupted";
 480                 err = -EFSBADCRC;
 481                 goto corrupted;
 482         }
 483         return 0;
 484
 485 corrupted:
 486         ext4_error_inode(inode, function, line, 0,
 487                          "pblk %llu bad header/extent: %s - magic %x, "
 488                          "entries %u, max %u(%u), depth %u(%u)",
 489                          (unsigned long long) pblk, error_msg,
 490                          le16_to_cpu(eh->eh_magic),
 491                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 492                          max, le16_to_cpu(eh->eh_depth), depth);
 493         return err;
 494 }
 495
 496 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 497         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 498
 499 int ext4_ext_check_inode(struct inode *inode)
 500 {
 501         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 502 }
 503
 504 static struct buffer_head *
 505 __read_extent_tree_block(const char *function, unsigned int line,
 506                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 507                          int flags)
 508 {
 509         struct buffer_head              *bh;
 510         int                             err;
 511
 512         bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
 513         if (unlikely(!bh))
 514                 return ERR_PTR(-ENOMEM);
 515
 516         if (!bh_uptodate_or_lock(bh)) {
 517                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 518                 err = bh_submit_read(bh);
 519                 if (err < 0)
 520                         goto errout;
 521         }
 522         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 523                 return bh;
 524         err = __ext4_ext_check(function, line, inode,
 525                                ext_block_hdr(bh), depth, pblk);
 526         if (err)
 527                 goto errout;
 528         set_buffer_verified(bh);
 529         /*
 530          * If this is a leaf block, cache all of its entries
 531          */
 532         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 533                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 534                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 535                 ext4_lblk_t prev = 0;
 536                 int i;
 537
 538                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 539                         unsigned int status = EXTENT_STATUS_WRITTEN;
 540                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 541                         int len = ext4_ext_get_actual_len(ex);
 542
 543                         if (prev && (prev != lblk))
 544                                 ext4_es_cache_extent(inode, prev,
 545                                                      lblk - prev, ~0,
 546                                                      EXTENT_STATUS_HOLE);
 547
 548                         if (ext4_ext_is_unwritten(ex))
 549                                 status = EXTENT_STATUS_UNWRITTEN;
 550                         ext4_es_cache_extent(inode, lblk, len,
 551                                              ext4_ext_pblock(ex), status);
 552                         prev = lblk + len;
 553                 }
 554         }
 555         return bh;
 556 errout:
 557         put_bh(bh);
 558         return ERR_PTR(err);
 559
 560 }
 561
 562 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 563         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 564                                  (depth), (flags))
 565
 566 /*
 567  * This function is called to cache a file's extent information in the
 568  * extent status tree
 569  */
 570 int ext4_ext_precache(struct inode *inode)
 571 {
 572         struct ext4_inode_info *ei = EXT4_I(inode);
 573         struct ext4_ext_path *path = NULL;
 574         struct buffer_head *bh;
 575         int i = 0, depth, ret = 0;
 576
 577         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 578                 return 0;       /* not an extent-mapped inode */
 579
 580         down_read(&ei->i_data_sem);
 581         depth = ext_depth(inode);
 582
 583         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 584                        GFP_NOFS);
 585         if (path == NULL) {
 586                 up_read(&ei->i_data_sem);
 587                 return -ENOMEM;
 588         }
 589
 590         /* Don't cache anything if there are no external extent blocks */
 591         if (depth == 0)
 592                 goto out;
 593         path[0].p_hdr = ext_inode_hdr(inode);
 594         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 595         if (ret)
 596                 goto out;
 597         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 598         while (i >= 0) {
 599                 /*
 600                  * If this is a leaf block or we've reached the end of
 601                  * the index block, go up
 602                  */
 603                 if ((i == depth) ||
 604                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 605                         brelse(path[i].p_bh);
 606                         path[i].p_bh = NULL;
 607                         i--;
 608                         continue;
 609                 }
 610                 bh = read_extent_tree_block(inode,
 611                                             ext4_idx_pblock(path[i].p_idx++),
 612                                             depth - i - 1,
 613                                             EXT4_EX_FORCE_CACHE);
 614                 if (IS_ERR(bh)) {
 615                         ret = PTR_ERR(bh);
 616                         break;
 617                 }
 618                 i++;
 619                 path[i].p_bh = bh;
 620                 path[i].p_hdr = ext_block_hdr(bh);
 621                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 622         }
 623         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 624 out:
 625         up_read(&ei->i_data_sem);
 626         ext4_ext_drop_refs(path);
 627         kfree(path);
 628         return ret;
 629 }
 630
 631 #ifdef EXT_DEBUG
 632 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 633 {
 634         int k, l = path->p_depth;
 635
 636         ext_debug("path:");
 637         for (k = 0; k <= l; k++, path++) {
 638                 if (path->p_idx) {
 639                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 640                             ext4_idx_pblock(path->p_idx));
 641                 } else if (path->p_ext) {
 642                         ext_debug("  %d:[%d]%d:%llu ",
 643                                   le32_to_cpu(path->p_ext->ee_block),
 644                                   ext4_ext_is_unwritten(path->p_ext),
 645                                   ext4_ext_get_actual_len(path->p_ext),
 646                                   ext4_ext_pblock(path->p_ext));
 647                 } else
 648                         ext_debug("  []");
 649         }
 650         ext_debug("\n");
 651 }
 652
 653 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 654 {
 655         int depth = ext_depth(inode);
 656         struct ext4_extent_header *eh;
 657         struct ext4_extent *ex;
 658         int i;
 659
 660         if (!path)
 661                 return;
 662
 663         eh = path[depth].p_hdr;
 664         ex = EXT_FIRST_EXTENT(eh);
 665
 666         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 667
 668         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 669                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 670                           ext4_ext_is_unwritten(ex),
 671                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 672         }
 673         ext_debug("\n");
 674 }
 675
 676 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 677                         ext4_fsblk_t newblock, int level)
 678 {
 679         int depth = ext_depth(inode);
 680         struct ext4_extent *ex;
 681
 682         if (depth != level) {
 683                 struct ext4_extent_idx *idx;
 684                 idx = path[level].p_idx;
 685                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 686                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 687                                         le32_to_cpu(idx->ei_block),
 688                                         ext4_idx_pblock(idx),
 689                                         newblock);
 690                         idx++;
 691                 }
 692
 693                 return;
 694         }
 695
 696         ex = path[depth].p_ext;
 697         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 698                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 699                                 le32_to_cpu(ex->ee_block),
 700                                 ext4_ext_pblock(ex),
 701                                 ext4_ext_is_unwritten(ex),
 702                                 ext4_ext_get_actual_len(ex),
 703                                 newblock);
 704                 ex++;
 705         }
 706 }
 707
 708 #else
 709 #define ext4_ext_show_path(inode, path)
 710 #define ext4_ext_show_leaf(inode, path)
 711 #define ext4_ext_show_move(inode, path, newblock, level)
 712 #endif
 713
 714 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 715 {
 716         int depth, i;
 717
 718         if (!path)
 719                 return;
 720         depth = path->p_depth;
 721         for (i = 0; i <= depth; i++, path++)
 722                 if (path->p_bh) {
 723                         brelse(path->p_bh);
 724                         path->p_bh = NULL;
 725                 }
 726 }
 727
 728 /*
 729  * ext4_ext_binsearch_idx:
 730  * binary search for the closest index of the given block
 731  * the header must be checked before calling this
 732  */
 733 static void
 734 ext4_ext_binsearch_idx(struct inode *inode,
 735                         struct ext4_ext_path *path, ext4_lblk_t block)
 736 {
 737         struct ext4_extent_header *eh = path->p_hdr;
 738         struct ext4_extent_idx *r, *l, *m;
 739
 740
 741         ext_debug("binsearch for %u(idx):  ", block);
 742
 743         l = EXT_FIRST_INDEX(eh) + 1;
 744         r = EXT_LAST_INDEX(eh);
 745         while (l <= r) {
 746                 m = l + (r - l) / 2;
 747                 if (block < le32_to_cpu(m->ei_block))
 748                         r = m - 1;
 749                 else
 750                         l = m + 1;
 751                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 752                                 m, le32_to_cpu(m->ei_block),
 753                                 r, le32_to_cpu(r->ei_block));
 754         }
 755
 756         path->p_idx = l - 1;
 757         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 758                   ext4_idx_pblock(path->p_idx));
 759
 760 #ifdef CHECK_BINSEARCH
 761         {
 762                 struct ext4_extent_idx *chix, *ix;
 763                 int k;
 764
 765                 chix = ix = EXT_FIRST_INDEX(eh);
 766                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 767                   if (k != 0 &&
 768                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 769                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 770                                        "first=0x%p\n", k,
 771                                        ix, EXT_FIRST_INDEX(eh));
 772                                 printk(KERN_DEBUG "%u <= %u\n",
 773                                        le32_to_cpu(ix->ei_block),
 774                                        le32_to_cpu(ix[-1].ei_block));
 775                         }
 776                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 777                                            <= le32_to_cpu(ix[-1].ei_block));
 778                         if (block < le32_to_cpu(ix->ei_block))
 779                                 break;
 780                         chix = ix;
 781                 }
 782                 BUG_ON(chix != path->p_idx);
 783         }
 784 #endif
 785
 786 }
 787
 788 /*
 789  * ext4_ext_binsearch:
 790  * binary search for closest extent of the given block
 791  * the header must be checked before calling this
 792  */
 793 static void
 794 ext4_ext_binsearch(struct inode *inode,
 795                 struct ext4_ext_path *path, ext4_lblk_t block)
 796 {
 797         struct ext4_extent_header *eh = path->p_hdr;
 798         struct ext4_extent *r, *l, *m;
 799
 800         if (eh->eh_entries == 0) {
 801                 /*
 802                  * this leaf is empty:
 803                  * we get such a leaf in split/add case
 804                  */
 805                 return;
 806         }
 807
 808         ext_debug("binsearch for %u:  ", block);
 809
 810         l = EXT_FIRST_EXTENT(eh) + 1;
 811         r = EXT_LAST_EXTENT(eh);
 812
 813         while (l <= r) {
 814                 m = l + (r - l) / 2;
 815                 if (block < le32_to_cpu(m->ee_block))
 816                         r = m - 1;
 817                 else
 818                         l = m + 1;
 819                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 820                                 m, le32_to_cpu(m->ee_block),
 821                                 r, le32_to_cpu(r->ee_block));
 822         }
 823
 824         path->p_ext = l - 1;
 825         ext_debug("  -> %d:%llu:[%d]%d ",
 826                         le32_to_cpu(path->p_ext->ee_block),
 827                         ext4_ext_pblock(path->p_ext),
 828                         ext4_ext_is_unwritten(path->p_ext),
 829                         ext4_ext_get_actual_len(path->p_ext));
 830
 831 #ifdef CHECK_BINSEARCH
 832         {
 833                 struct ext4_extent *chex, *ex;
 834                 int k;
 835
 836                 chex = ex = EXT_FIRST_EXTENT(eh);
 837                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 838                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 839                                           <= le32_to_cpu(ex[-1].ee_block));
 840                         if (block < le32_to_cpu(ex->ee_block))
 841                                 break;
 842                         chex = ex;
 843                 }
 844                 BUG_ON(chex != path->p_ext);
 845         }
 846 #endif
 847
 848 }
 849
 850 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 851 {
 852         struct ext4_extent_header *eh;
 853
 854         eh = ext_inode_hdr(inode);
 855         eh->eh_depth = 0;
 856         eh->eh_entries = 0;
 857         eh->eh_magic = EXT4_EXT_MAGIC;
 858         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 859         ext4_mark_inode_dirty(handle, inode);
 860         return 0;
 861 }
 862
 863 struct ext4_ext_path *
 864 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 865                  struct ext4_ext_path **orig_path, int flags)
 866 {
 867         struct ext4_extent_header *eh;
 868         struct buffer_head *bh;
 869         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 870         short int depth, i, ppos = 0;
 871         int ret;
 872
 873         eh = ext_inode_hdr(inode);
 874         depth = ext_depth(inode);
 875
 876         if (path) {
 877                 ext4_ext_drop_refs(path);
 878                 if (depth > path[0].p_maxdepth) {
 879                         kfree(path);
 880                         *orig_path = path = NULL;
 881                 }
 882         }
 883         if (!path) {
 884                 /* account possible depth increase */
 885                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 886                                 GFP_NOFS);
 887                 if (unlikely(!path))
 888                         return ERR_PTR(-ENOMEM);
 889                 path[0].p_maxdepth = depth + 1;
 890         }
 891         path[0].p_hdr = eh;
 892         path[0].p_bh = NULL;
 893
 894         i = depth;
 895         /* walk through the tree */
 896         while (i) {
 897                 ext_debug("depth %d: num %d, max %d\n",
 898                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 899
 900                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 901                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 902                 path[ppos].p_depth = i;
 903                 path[ppos].p_ext = NULL;
 904
 905                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 906                                             flags);
 907                 if (IS_ERR(bh)) {
 908                         ret = PTR_ERR(bh);
 909                         goto err;
 910                 }
 911
 912                 eh = ext_block_hdr(bh);
 913                 ppos++;
 914                 if (unlikely(ppos > depth)) {
 915                         put_bh(bh);
 916                         EXT4_ERROR_INODE(inode,
 917                                          "ppos %d > depth %d", ppos, depth);
 918                         ret = -EFSCORRUPTED;
 919                         goto err;
 920                 }
 921                 path[ppos].p_bh = bh;
 922                 path[ppos].p_hdr = eh;
 923         }
 924
 925         path[ppos].p_depth = i;
 926         path[ppos].p_ext = NULL;
 927         path[ppos].p_idx = NULL;
 928
 929         /* find extent */
 930         ext4_ext_binsearch(inode, path + ppos, block);
 931         /* if not an empty leaf */
 932         if (path[ppos].p_ext)
 933                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 934
 935         ext4_ext_show_path(inode, path);
 936
 937         return path;
 938
 939 err:
 940         ext4_ext_drop_refs(path);
 941         kfree(path);
 942         if (orig_path)
 943                 *orig_path = NULL;
 944         return ERR_PTR(ret);
 945 }
 946
 947 /*
 948  * ext4_ext_insert_index:
 949  * insert new index [@logical;@ptr] into the block at @curp;
 950  * check where to insert: before @curp or after @curp
 951  */
 952 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 953                                  struct ext4_ext_path *curp,
 954                                  int logical, ext4_fsblk_t ptr)
 955 {
 956         struct ext4_extent_idx *ix;
 957         int len, err;
 958
 959         err = ext4_ext_get_access(handle, inode, curp);
 960         if (err)
 961                 return err;
 962
 963         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 964                 EXT4_ERROR_INODE(inode,
 965                                  "logical %d == ei_block %d!",
 966                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 967                 return -EFSCORRUPTED;
 968         }
 969
 970         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 971                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 972                 EXT4_ERROR_INODE(inode,
 973                                  "eh_entries %d >= eh_max %d!",
 974                                  le16_to_cpu(curp->p_hdr->eh_entries),
 975                                  le16_to_cpu(curp->p_hdr->eh_max));
 976                 return -EFSCORRUPTED;
 977         }
 978
 979         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 980                 /* insert after */
 981                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 982                 ix = curp->p_idx + 1;
 983         } else {
 984                 /* insert before */
 985                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 986                 ix = curp->p_idx;
 987         }
 988
 989         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 990         BUG_ON(len < 0);
 991         if (len > 0) {
 992                 ext_debug("insert new index %d: "
 993                                 "move %d indices from 0x%p to 0x%p\n",
 994                                 logical, len, ix, ix + 1);
 995                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 996         }
 997
 998         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 999                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1000                 return -EFSCORRUPTED;
1001         }
1002
1003         ix->ei_block = cpu_to_le32(logical);
1004         ext4_idx_store_pblock(ix, ptr);
1005         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1006
1007         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1008                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1009                 return -EFSCORRUPTED;
1010         }
1011
1012         err = ext4_ext_dirty(handle, inode, curp);
1013         ext4_std_error(inode->i_sb, err);
1014
1015         return err;
1016 }
1017
1018 /*
1019  * ext4_ext_split:
1020  * inserts new subtree into the path, using free index entry
1021  * at depth @at:
1022  * - allocates all needed blocks (new leaf and all intermediate index blocks)
1023  * - makes decision where to split
1024  * - moves remaining extents and index entries (right to the split point)
1025  *   into the newly allocated blocks
1026  * - initializes subtree
1027  */
1028 static int ext4_ext_split(handle_t *handle, struct inode *inode,
1029                           unsigned int flags,
1030                           struct ext4_ext_path *path,
1031                           struct ext4_extent *newext, int at)
1032 {
1033         struct buffer_head *bh = NULL;
1034         int depth = ext_depth(inode);
1035         struct ext4_extent_header *neh;
1036         struct ext4_extent_idx *fidx;
1037         int i = at, k, m, a;
1038         ext4_fsblk_t newblock, oldblock;
1039         __le32 border;
1040         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1041         int err = 0;
1042
1043         /* make decision: where to split? */
1044         /* FIXME: now decision is simplest: at current extent */
1045
1046         /* if current leaf will be split, then we should use
1047          * border from split point */
1048         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1049                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1050                 return -EFSCORRUPTED;
1051         }
1052         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1053                 border = path[depth].p_ext[1].ee_block;
1054                 ext_debug("leaf will be split."
1055                                 " next leaf starts at %d\n",
1056                                   le32_to_cpu(border));
1057         } else {
1058                 border = newext->ee_block;
1059                 ext_debug("leaf will be added."
1060                                 " next leaf starts at %d\n",
1061                                 le32_to_cpu(border));
1062         }
1063
1064         /*
1065          * If error occurs, then we break processing
1066          * and mark filesystem read-only. index won't
1067          * be inserted and tree will be in consistent
1068          * state. Next mount will repair buffers too.
1069          */
1070
1071         /*
1072          * Get array to track all allocated blocks.
1073          * We need this to handle errors and free blocks
1074          * upon them.
1075          */
1076         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1077         if (!ablocks)
1078                 return -ENOMEM;
1079
1080         /* allocate all needed blocks */
1081         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1082         for (a = 0; a < depth - at; a++) {
1083                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1084                                                    newext, &err, flags);
1085                 if (newblock == 0)
1086                         goto cleanup;
1087                 ablocks[a] = newblock;
1088         }
1089
1090         /* initialize new leaf */
1091         newblock = ablocks[--a];
1092         if (unlikely(newblock == 0)) {
1093                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1094                 err = -EFSCORRUPTED;
1095                 goto cleanup;
1096         }
1097         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1098         if (unlikely(!bh)) {
1099                 err = -ENOMEM;
1100                 goto cleanup;
1101         }
1102         lock_buffer(bh);
1103
1104         err = ext4_journal_get_create_access(handle, bh);
1105         if (err)
1106                 goto cleanup;
1107
1108         neh = ext_block_hdr(bh);
1109         neh->eh_entries = 0;
1110         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1111         neh->eh_magic = EXT4_EXT_MAGIC;
1112         neh->eh_depth = 0;
1113
1114         /* move remainder of path[depth] to the new leaf */
1115         if (unlikely(path[depth].p_hdr->eh_entries !=
1116                      path[depth].p_hdr->eh_max)) {
1117                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1118                                  path[depth].p_hdr->eh_entries,
1119                                  path[depth].p_hdr->eh_max);
1120                 err = -EFSCORRUPTED;
1121                 goto cleanup;
1122         }
1123         /* start copy from next extent */
1124         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1125         ext4_ext_show_move(inode, path, newblock, depth);
1126         if (m) {
1127                 struct ext4_extent *ex;
1128                 ex = EXT_FIRST_EXTENT(neh);
1129                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1130                 le16_add_cpu(&neh->eh_entries, m);
1131         }
1132
1133         ext4_extent_block_csum_set(inode, neh);
1134         set_buffer_uptodate(bh);
1135         unlock_buffer(bh);
1136
1137         err = ext4_handle_dirty_metadata(handle, inode, bh);
1138         if (err)
1139                 goto cleanup;
1140         brelse(bh);
1141         bh = NULL;
1142
1143         /* correct old leaf */
1144         if (m) {
1145                 err = ext4_ext_get_access(handle, inode, path + depth);
1146                 if (err)
1147                         goto cleanup;
1148                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1149                 err = ext4_ext_dirty(handle, inode, path + depth);
1150                 if (err)
1151                         goto cleanup;
1152
1153         }
1154
1155         /* create intermediate indexes */
1156         k = depth - at - 1;
1157         if (unlikely(k < 0)) {
1158                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1159                 err = -EFSCORRUPTED;
1160                 goto cleanup;
1161         }
1162         if (k)
1163                 ext_debug("create %d intermediate indices\n", k);
1164         /* insert new index into current index block */
1165         /* current depth stored in i var */
1166         i = depth - 1;
1167         while (k--) {
1168                 oldblock = newblock;
1169                 newblock = ablocks[--a];
1170                 bh = sb_getblk(inode->i_sb, newblock);
1171                 if (unlikely(!bh)) {
1172                         err = -ENOMEM;
1173                         goto cleanup;
1174                 }
1175                 lock_buffer(bh);
1176
1177                 err = ext4_journal_get_create_access(handle, bh);
1178                 if (err)
1179                         goto cleanup;
1180
1181                 neh = ext_block_hdr(bh);
1182                 neh->eh_entries = cpu_to_le16(1);
1183                 neh->eh_magic = EXT4_EXT_MAGIC;
1184                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1185                 neh->eh_depth = cpu_to_le16(depth - i);
1186                 fidx = EXT_FIRST_INDEX(neh);
1187                 fidx->ei_block = border;
1188                 ext4_idx_store_pblock(fidx, oldblock);
1189
1190                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1191                                 i, newblock, le32_to_cpu(border), oldblock);
1192
1193                 /* move remainder of path[i] to the new index block */
1194                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1195                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1196                         EXT4_ERROR_INODE(inode,
1197                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1198                                          le32_to_cpu(path[i].p_ext->ee_block));
1199                         err = -EFSCORRUPTED;
1200                         goto cleanup;
1201                 }
1202                 /* start copy indexes */
1203                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1204                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1205                                 EXT_MAX_INDEX(path[i].p_hdr));
1206                 ext4_ext_show_move(inode, path, newblock, i);
1207                 if (m) {
1208                         memmove(++fidx, path[i].p_idx,
1209                                 sizeof(struct ext4_extent_idx) * m);
1210                         le16_add_cpu(&neh->eh_entries, m);
1211                 }
1212                 ext4_extent_block_csum_set(inode, neh);
1213                 set_buffer_uptodate(bh);
1214                 unlock_buffer(bh);
1215
1216                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1217                 if (err)
1218                         goto cleanup;
1219                 brelse(bh);
1220                 bh = NULL;
1221
1222                 /* correct old index */
1223                 if (m) {
1224                         err = ext4_ext_get_access(handle, inode, path + i);
1225                         if (err)
1226                                 goto cleanup;
1227                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1228                         err = ext4_ext_dirty(handle, inode, path + i);
1229                         if (err)
1230                                 goto cleanup;
1231                 }
1232
1233                 i--;
1234         }
1235
1236         /* insert new index */
1237         err = ext4_ext_insert_index(handle, inode, path + at,
1238                                     le32_to_cpu(border), newblock);
1239
1240 cleanup:
1241         if (bh) {
1242                 if (buffer_locked(bh))
1243                         unlock_buffer(bh);
1244                 brelse(bh);
1245         }
1246
1247         if (err) {
1248                 /* free all allocated blocks in error case */
1249                 for (i = 0; i < depth; i++) {
1250                         if (!ablocks[i])
1251                                 continue;
1252                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1253                                          EXT4_FREE_BLOCKS_METADATA);
1254                 }
1255         }
1256         kfree(ablocks);
1257
1258         return err;
1259 }
1260
1261 /*
1262  * ext4_ext_grow_indepth:
1263  * implements tree growing procedure:
1264  * - allocates new block
1265  * - moves top-level data (index block or leaf) into the new block
1266  * - initializes new top-level, creating index that points to the
1267  *   just created block
1268  */
1269 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1270                                  unsigned int flags)
1271 {
1272         struct ext4_extent_header *neh;
1273         struct buffer_head *bh;
1274         ext4_fsblk_t newblock, goal = 0;
1275         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1276         int err = 0;
1277
1278         /* Try to prepend new index to old one */
1279         if (ext_depth(inode))
1280                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1281         if (goal > le32_to_cpu(es->s_first_data_block)) {
1282                 flags |= EXT4_MB_HINT_TRY_GOAL;
1283                 goal--;
1284         } else
1285                 goal = ext4_inode_to_goal_block(inode);
1286         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1287                                         NULL, &err);
1288         if (newblock == 0)
1289                 return err;
1290
1291         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1292         if (unlikely(!bh))
1293                 return -ENOMEM;
1294         lock_buffer(bh);
1295
1296         err = ext4_journal_get_create_access(handle, bh);
1297         if (err) {
1298                 unlock_buffer(bh);
1299                 goto out;
1300         }
1301
1302         /* move top-level index/leaf into new block */
1303         memmove(bh->b_data, EXT4_I(inode)->i_data,
1304                 sizeof(EXT4_I(inode)->i_data));
1305
1306         /* set size of new block */
1307         neh = ext_block_hdr(bh);
1308         /* old root could have indexes or leaves
1309          * so calculate e_max right way */
1310         if (ext_depth(inode))
1311                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1312         else
1313                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1314         neh->eh_magic = EXT4_EXT_MAGIC;
1315         ext4_extent_block_csum_set(inode, neh);
1316         set_buffer_uptodate(bh);
1317         unlock_buffer(bh);
1318
1319         err = ext4_handle_dirty_metadata(handle, inode, bh);
1320         if (err)
1321                 goto out;
1322
1323         /* Update top-level index: num,max,pointer */
1324         neh = ext_inode_hdr(inode);
1325         neh->eh_entries = cpu_to_le16(1);
1326         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1327         if (neh->eh_depth == 0) {
1328                 /* Root extent block becomes index block */
1329                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1330                 EXT_FIRST_INDEX(neh)->ei_block =
1331                         EXT_FIRST_EXTENT(neh)->ee_block;
1332         }
1333         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1334                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1335                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1336                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1337
1338         le16_add_cpu(&neh->eh_depth, 1);
1339         ext4_mark_inode_dirty(handle, inode);
1340 out:
1341         brelse(bh);
1342
1343         return err;
1344 }
1345
1346 /*
1347  * ext4_ext_create_new_leaf:
1348  * finds empty index and adds new leaf.
1349  * if no free index is found, then it requests in-depth growing.
1350  */
1351 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1352                                     unsigned int mb_flags,
1353                                     unsigned int gb_flags,
1354                                     struct ext4_ext_path **ppath,
1355                                     struct ext4_extent *newext)
1356 {
1357         struct ext4_ext_path *path = *ppath;
1358         struct ext4_ext_path *curp;
1359         int depth, i, err = 0;
1360
1361 repeat:
1362         i = depth = ext_depth(inode);
1363
1364         /* walk up to the tree and look for free index entry */
1365         curp = path + depth;
1366         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1367                 i--;
1368                 curp--;
1369         }
1370
1371         /* we use already allocated block for index block,
1372          * so subsequent data blocks should be contiguous */
1373         if (EXT_HAS_FREE_INDEX(curp)) {
1374                 /* if we found index with free entry, then use that
1375                  * entry: create all needed subtree and add new leaf */
1376                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1377                 if (err)
1378                         goto out;
1379
1380                 /* refill path */
1381                 path = ext4_find_extent(inode,
1382                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1383                                     ppath, gb_flags);
1384                 if (IS_ERR(path))
1385                         err = PTR_ERR(path);
1386         } else {
1387                 /* tree is full, time to grow in depth */
1388                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1389                 if (err)
1390                         goto out;
1391
1392                 /* refill path */
1393                 path = ext4_find_extent(inode,
1394                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1395                                     ppath, gb_flags);
1396                 if (IS_ERR(path)) {
1397                         err = PTR_ERR(path);
1398                         goto out;
1399                 }
1400
1401                 /*
1402                  * only first (depth 0 -> 1) produces free space;
1403                  * in all other cases we have to split the grown tree
1404                  */
1405                 depth = ext_depth(inode);
1406                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1407                         /* now we need to split */
1408                         goto repeat;
1409                 }
1410         }
1411
1412 out:
1413         return err;
1414 }
1415
1416 /*
1417  * search the closest allocated block to the left for *logical
1418  * and returns it at @logical + it's physical address at @phys
1419  * if *logical is the smallest allocated block, the function
1420  * returns 0 at @phys
1421  * return value contains 0 (success) or error code
1422  */
1423 static int ext4_ext_search_left(struct inode *inode,
1424                                 struct ext4_ext_path *path,
1425                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1426 {
1427         struct ext4_extent_idx *ix;
1428         struct ext4_extent *ex;
1429         int depth, ee_len;
1430
1431         if (unlikely(path == NULL)) {
1432                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1433                 return -EFSCORRUPTED;
1434         }
1435         depth = path->p_depth;
1436         *phys = 0;
1437
1438         if (depth == 0 && path->p_ext == NULL)
1439                 return 0;
1440
1441         /* usually extent in the path covers blocks smaller
1442          * then *logical, but it can be that extent is the
1443          * first one in the file */
1444
1445         ex = path[depth].p_ext;
1446         ee_len = ext4_ext_get_actual_len(ex);
1447         if (*logical < le32_to_cpu(ex->ee_block)) {
1448                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1449                         EXT4_ERROR_INODE(inode,
1450                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1451                                          *logical, le32_to_cpu(ex->ee_block));
1452                         return -EFSCORRUPTED;
1453                 }
1454                 while (--depth >= 0) {
1455                         ix = path[depth].p_idx;
1456                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1457                                 EXT4_ERROR_INODE(inode,
1458                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1459                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1460                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1461                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1462                                   depth);
1463                                 return -EFSCORRUPTED;
1464                         }
1465                 }
1466                 return 0;
1467         }
1468
1469         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1470                 EXT4_ERROR_INODE(inode,
1471                                  "logical %d < ee_block %d + ee_len %d!",
1472                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1473                 return -EFSCORRUPTED;
1474         }
1475
1476         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1477         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1478         return 0;
1479 }
1480
1481 /*
1482  * search the closest allocated block to the right for *logical
1483  * and returns it at @logical + it's physical address at @phys
1484  * if *logical is the largest allocated block, the function
1485  * returns 0 at @phys
1486  * return value contains 0 (success) or error code
1487  */
1488 static int ext4_ext_search_right(struct inode *inode,
1489                                  struct ext4_ext_path *path,
1490                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1491                                  struct ext4_extent **ret_ex)
1492 {
1493         struct buffer_head *bh = NULL;
1494         struct ext4_extent_header *eh;
1495         struct ext4_extent_idx *ix;
1496         struct ext4_extent *ex;
1497         ext4_fsblk_t block;
1498         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1499         int ee_len;
1500
1501         if (unlikely(path == NULL)) {
1502                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1503                 return -EFSCORRUPTED;
1504         }
1505         depth = path->p_depth;
1506         *phys = 0;
1507
1508         if (depth == 0 && path->p_ext == NULL)
1509                 return 0;
1510
1511         /* usually extent in the path covers blocks smaller
1512          * then *logical, but it can be that extent is the
1513          * first one in the file */
1514
1515         ex = path[depth].p_ext;
1516         ee_len = ext4_ext_get_actual_len(ex);
1517         if (*logical < le32_to_cpu(ex->ee_block)) {
1518                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1519                         EXT4_ERROR_INODE(inode,
1520                                          "first_extent(path[%d].p_hdr) != ex",
1521                                          depth);
1522                         return -EFSCORRUPTED;
1523                 }
1524                 while (--depth >= 0) {
1525                         ix = path[depth].p_idx;
1526                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1527                                 EXT4_ERROR_INODE(inode,
1528                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1529                                                  *logical);
1530                                 return -EFSCORRUPTED;
1531                         }
1532                 }
1533                 goto found_extent;
1534         }
1535
1536         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1537                 EXT4_ERROR_INODE(inode,
1538                                  "logical %d < ee_block %d + ee_len %d!",
1539                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1540                 return -EFSCORRUPTED;
1541         }
1542
1543         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1544                 /* next allocated block in this leaf */
1545                 ex++;
1546                 goto found_extent;
1547         }
1548
1549         /* go up and search for index to the right */
1550         while (--depth >= 0) {
1551                 ix = path[depth].p_idx;
1552                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1553                         goto got_index;
1554         }
1555
1556         /* we've gone up to the root and found no index to the right */
1557         return 0;
1558
1559 got_index:
1560         /* we've found index to the right, let's
1561          * follow it and find the closest allocated
1562          * block to the right */
1563         ix++;
1564         block = ext4_idx_pblock(ix);
1565         while (++depth < path->p_depth) {
1566                 /* subtract from p_depth to get proper eh_depth */
1567                 bh = read_extent_tree_block(inode, block,
1568                                             path->p_depth - depth, 0);
1569                 if (IS_ERR(bh))
1570                         return PTR_ERR(bh);
1571                 eh = ext_block_hdr(bh);
1572                 ix = EXT_FIRST_INDEX(eh);
1573                 block = ext4_idx_pblock(ix);
1574                 put_bh(bh);
1575         }
1576
1577         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1578         if (IS_ERR(bh))
1579                 return PTR_ERR(bh);
1580         eh = ext_block_hdr(bh);
1581         ex = EXT_FIRST_EXTENT(eh);
1582 found_extent:
1583         *logical = le32_to_cpu(ex->ee_block);
1584         *phys = ext4_ext_pblock(ex);
1585         *ret_ex = ex;
1586         if (bh)
1587                 put_bh(bh);
1588         return 0;
1589 }
1590
1591 /*
1592  * ext4_ext_next_allocated_block:
1593  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1594  * NOTE: it considers block number from index entry as
1595  * allocated block. Thus, index entries have to be consistent
1596  * with leaves.
1597  */
1598 ext4_lblk_t
1599 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1600 {
1601         int depth;
1602
1603         BUG_ON(path == NULL);
1604         depth = path->p_depth;
1605
1606         if (depth == 0 && path->p_ext == NULL)
1607                 return EXT_MAX_BLOCKS;
1608
1609         while (depth >= 0) {
1610                 if (depth == path->p_depth) {
1611                         /* leaf */
1612                         if (path[depth].p_ext &&
1613                                 path[depth].p_ext !=
1614                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1615                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1616                 } else {
1617                         /* index */
1618                         if (path[depth].p_idx !=
1619                                         EXT_LAST_INDEX(path[depth].p_hdr))
1620                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1621                 }
1622                 depth--;
1623         }
1624
1625         return EXT_MAX_BLOCKS;
1626 }
1627
1628 /*
1629  * ext4_ext_next_leaf_block:
1630  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1631  */
1632 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1633 {
1634         int depth;
1635
1636         BUG_ON(path == NULL);
1637         depth = path->p_depth;
1638
1639         /* zero-tree has no leaf blocks at all */
1640         if (depth == 0)
1641                 return EXT_MAX_BLOCKS;
1642
1643         /* go to index block */
1644         depth--;
1645
1646         while (depth >= 0) {
1647                 if (path[depth].p_idx !=
1648                                 EXT_LAST_INDEX(path[depth].p_hdr))
1649                         return (ext4_lblk_t)
1650                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1651                 depth--;
1652         }
1653
1654         return EXT_MAX_BLOCKS;
1655 }
1656
1657 /*
1658  * ext4_ext_correct_indexes:
1659  * if leaf gets modified and modified extent is first in the leaf,
1660  * then we have to correct all indexes above.
1661  * TODO: do we need to correct tree in all cases?
1662  */
1663 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1664                                 struct ext4_ext_path *path)
1665 {
1666         struct ext4_extent_header *eh;
1667         int depth = ext_depth(inode);
1668         struct ext4_extent *ex;
1669         __le32 border;
1670         int k, err = 0;
1671
1672         eh = path[depth].p_hdr;
1673         ex = path[depth].p_ext;
1674
1675         if (unlikely(ex == NULL || eh == NULL)) {
1676                 EXT4_ERROR_INODE(inode,
1677                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1678                 return -EFSCORRUPTED;
1679         }
1680
1681         if (depth == 0) {
1682                 /* there is no tree at all */
1683                 return 0;
1684         }
1685
1686         if (ex != EXT_FIRST_EXTENT(eh)) {
1687                 /* we correct tree if first leaf got modified only */
1688                 return 0;
1689         }
1690
1691         /*
1692          * TODO: we need correction if border is smaller than current one
1693          */
1694         k = depth - 1;
1695         border = path[depth].p_ext->ee_block;
1696         err = ext4_ext_get_access(handle, inode, path + k);
1697         if (err)
1698                 return err;
1699         path[k].p_idx->ei_block = border;
1700         err = ext4_ext_dirty(handle, inode, path + k);
1701         if (err)
1702                 return err;
1703
1704         while (k--) {
1705                 /* change all left-side indexes */
1706                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1707                         break;
1708                 err = ext4_ext_get_access(handle, inode, path + k);
1709                 if (err)
1710                         break;
1711                 path[k].p_idx->ei_block = border;
1712                 err = ext4_ext_dirty(handle, inode, path + k);
1713                 if (err)
1714                         break;
1715         }
1716
1717         return err;
1718 }
1719
1720 int
1721 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1722                                 struct ext4_extent *ex2)
1723 {
1724         unsigned short ext1_ee_len, ext2_ee_len;
1725
1726         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1727                 return 0;
1728
1729         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1730         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1731
1732         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1733                         le32_to_cpu(ex2->ee_block))
1734                 return 0;
1735
1736         /*
1737          * To allow future support for preallocated extents to be added
1738          * as an RO_COMPAT feature, refuse to merge to extents if
1739          * this can result in the top bit of ee_len being set.
1740          */
1741         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1742                 return 0;
1743         if (ext4_ext_is_unwritten(ex1) &&
1744             (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1745              atomic_read(&EXT4_I(inode)->i_unwritten) ||
1746              (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1747                 return 0;
1748 #ifdef AGGRESSIVE_TEST
1749         if (ext1_ee_len >= 4)
1750                 return 0;
1751 #endif
1752
1753         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1754                 return 1;
1755         return 0;
1756 }
1757
1758 /*
1759  * This function tries to merge the "ex" extent to the next extent in the tree.
1760  * It always tries to merge towards right. If you want to merge towards
1761  * left, pass "ex - 1" as argument instead of "ex".
1762  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1763  * 1 if they got merged.
1764  */
1765 static int ext4_ext_try_to_merge_right(struct inode *inode,
1766                                  struct ext4_ext_path *path,
1767                                  struct ext4_extent *ex)
1768 {
1769         struct ext4_extent_header *eh;
1770         unsigned int depth, len;
1771         int merge_done = 0, unwritten;
1772
1773         depth = ext_depth(inode);
1774         BUG_ON(path[depth].p_hdr == NULL);
1775         eh = path[depth].p_hdr;
1776
1777         while (ex < EXT_LAST_EXTENT(eh)) {
1778                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1779                         break;
1780                 /* merge with next extent! */
1781                 unwritten = ext4_ext_is_unwritten(ex);
1782                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1783                                 + ext4_ext_get_actual_len(ex + 1));
1784                 if (unwritten)
1785                         ext4_ext_mark_unwritten(ex);
1786
1787                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1788                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1789                                 * sizeof(struct ext4_extent);
1790                         memmove(ex + 1, ex + 2, len);
1791                 }
1792                 le16_add_cpu(&eh->eh_entries, -1);
1793                 merge_done = 1;
1794                 WARN_ON(eh->eh_entries == 0);
1795                 if (!eh->eh_entries)
1796                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1797         }
1798
1799         return merge_done;
1800 }
1801
1802 /*
1803  * This function does a very simple check to see if we can collapse
1804  * an extent tree with a single extent tree leaf block into the inode.
1805  */
1806 static void ext4_ext_try_to_merge_up(handle_t *handle,
1807                                      struct inode *inode,
1808                                      struct ext4_ext_path *path)
1809 {
1810         size_t s;
1811         unsigned max_root = ext4_ext_space_root(inode, 0);
1812         ext4_fsblk_t blk;
1813
1814         if ((path[0].p_depth != 1) ||
1815             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1816             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1817                 return;
1818
1819         /*
1820          * We need to modify the block allocation bitmap and the block
1821          * group descriptor to release the extent tree block.  If we
1822          * can't get the journal credits, give up.
1823          */
1824         if (ext4_journal_extend(handle, 2))
1825                 return;
1826
1827         /*
1828          * Copy the extent data up to the inode
1829          */
1830         blk = ext4_idx_pblock(path[0].p_idx);
1831         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1832                 sizeof(struct ext4_extent_idx);
1833         s += sizeof(struct ext4_extent_header);
1834
1835         path[1].p_maxdepth = path[0].p_maxdepth;
1836         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1837         path[0].p_depth = 0;
1838         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1839                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1840         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1841
1842         brelse(path[1].p_bh);
1843         ext4_free_blocks(handle, inode, NULL, blk, 1,
1844                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1845 }
1846
1847 /*
1848  * This function tries to merge the @ex extent to neighbours in the tree.
1849  * return 1 if merge left else 0.
1850  */
1851 static void ext4_ext_try_to_merge(handle_t *handle,
1852                                   struct inode *inode,
1853                                   struct ext4_ext_path *path,
1854                                   struct ext4_extent *ex) {
1855         struct ext4_extent_header *eh;
1856         unsigned int depth;
1857         int merge_done = 0;
1858
1859         depth = ext_depth(inode);
1860         BUG_ON(path[depth].p_hdr == NULL);
1861         eh = path[depth].p_hdr;
1862
1863         if (ex > EXT_FIRST_EXTENT(eh))
1864                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1865
1866         if (!merge_done)
1867                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1868
1869         ext4_ext_try_to_merge_up(handle, inode, path);
1870 }
1871
1872 /*
1873  * check if a portion of the "newext" extent overlaps with an
1874  * existing extent.
1875  *
1876  * If there is an overlap discovered, it updates the length of the newext
1877  * such that there will be no overlap, and then returns 1.
1878  * If there is no overlap found, it returns 0.
1879  */
1880 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1881                                            struct inode *inode,
1882                                            struct ext4_extent *newext,
1883                                            struct ext4_ext_path *path)
1884 {
1885         ext4_lblk_t b1, b2;
1886         unsigned int depth, len1;
1887         unsigned int ret = 0;
1888
1889         b1 = le32_to_cpu(newext->ee_block);
1890         len1 = ext4_ext_get_actual_len(newext);
1891         depth = ext_depth(inode);
1892         if (!path[depth].p_ext)
1893                 goto out;
1894         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1895
1896         /*
1897          * get the next allocated block if the extent in the path
1898          * is before the requested block(s)
1899          */
1900         if (b2 < b1) {
1901                 b2 = ext4_ext_next_allocated_block(path);
1902                 if (b2 == EXT_MAX_BLOCKS)
1903                         goto out;
1904                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1905         }
1906
1907         /* check for wrap through zero on extent logical start block*/
1908         if (b1 + len1 < b1) {
1909                 len1 = EXT_MAX_BLOCKS - b1;
1910                 newext->ee_len = cpu_to_le16(len1);
1911                 ret = 1;
1912         }
1913
1914         /* check for overlap */
1915         if (b1 + len1 > b2) {
1916                 newext->ee_len = cpu_to_le16(b2 - b1);
1917                 ret = 1;
1918         }
1919 out:
1920         return ret;
1921 }
1922
1923 /*
1924  * ext4_ext_insert_extent:
1925  * tries to merge requsted extent into the existing extent or
1926  * inserts requested extent as new one into the tree,
1927  * creating new leaf in the no-space case.
1928  */
1929 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1930                                 struct ext4_ext_path **ppath,
1931                                 struct ext4_extent *newext, int gb_flags)
1932 {
1933         struct ext4_ext_path *path = *ppath;
1934         struct ext4_extent_header *eh;
1935         struct ext4_extent *ex, *fex;
1936         struct ext4_extent *nearex; /* nearest extent */
1937         struct ext4_ext_path *npath = NULL;
1938         int depth, len, err;
1939         ext4_lblk_t next;
1940         int mb_flags = 0, unwritten;
1941
1942         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1943                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1944         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1945                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1946                 return -EFSCORRUPTED;
1947         }
1948         depth = ext_depth(inode);
1949         ex = path[depth].p_ext;
1950         eh = path[depth].p_hdr;
1951         if (unlikely(path[depth].p_hdr == NULL)) {
1952                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1953                 return -EFSCORRUPTED;
1954         }
1955
1956         /* try to insert block into found extent and return */
1957         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1958
1959                 /*
1960                  * Try to see whether we should rather test the extent on
1961                  * right from ex, or from the left of ex. This is because
1962                  * ext4_find_extent() can return either extent on the
1963                  * left, or on the right from the searched position. This
1964                  * will make merging more effective.
1965                  */
1966                 if (ex < EXT_LAST_EXTENT(eh) &&
1967                     (le32_to_cpu(ex->ee_block) +
1968                     ext4_ext_get_actual_len(ex) <
1969                     le32_to_cpu(newext->ee_block))) {
1970                         ex += 1;
1971                         goto prepend;
1972                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1973                            (le32_to_cpu(newext->ee_block) +
1974                            ext4_ext_get_actual_len(newext) <
1975                            le32_to_cpu(ex->ee_block)))
1976                         ex -= 1;
1977
1978                 /* Try to append newex to the ex */
1979                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1980                         ext_debug("append [%d]%d block to %u:[%d]%d"
1981                                   "(from %llu)\n",
1982                                   ext4_ext_is_unwritten(newext),
1983                                   ext4_ext_get_actual_len(newext),
1984                                   le32_to_cpu(ex->ee_block),
1985                                   ext4_ext_is_unwritten(ex),
1986                                   ext4_ext_get_actual_len(ex),
1987                                   ext4_ext_pblock(ex));
1988                         err = ext4_ext_get_access(handle, inode,
1989                                                   path + depth);
1990                         if (err)
1991                                 return err;
1992                         unwritten = ext4_ext_is_unwritten(ex);
1993                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1994                                         + ext4_ext_get_actual_len(newext));
1995                         if (unwritten)
1996                                 ext4_ext_mark_unwritten(ex);
1997                         eh = path[depth].p_hdr;
1998                         nearex = ex;
1999                         goto merge;
2000                 }
2001
2002 prepend:
2003                 /* Try to prepend newex to the ex */
2004                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2005                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2006                                   "(from %llu)\n",
2007                                   le32_to_cpu(newext->ee_block),
2008                                   ext4_ext_is_unwritten(newext),
2009                                   ext4_ext_get_actual_len(newext),
2010                                   le32_to_cpu(ex->ee_block),
2011                                   ext4_ext_is_unwritten(ex),
2012                                   ext4_ext_get_actual_len(ex),
2013                                   ext4_ext_pblock(ex));
2014                         err = ext4_ext_get_access(handle, inode,
2015                                                   path + depth);
2016                         if (err)
2017                                 return err;
2018
2019                         unwritten = ext4_ext_is_unwritten(ex);
2020                         ex->ee_block = newext->ee_block;
2021                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2022                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2023                                         + ext4_ext_get_actual_len(newext));
2024                         if (unwritten)
2025                                 ext4_ext_mark_unwritten(ex);
2026                         eh = path[depth].p_hdr;
2027                         nearex = ex;
2028                         goto merge;
2029                 }
2030         }
2031
2032         depth = ext_depth(inode);
2033         eh = path[depth].p_hdr;
2034         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2035                 goto has_space;
2036
2037         /* probably next leaf has space for us? */
2038         fex = EXT_LAST_EXTENT(eh);
2039         next = EXT_MAX_BLOCKS;
2040         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2041                 next = ext4_ext_next_leaf_block(path);
2042         if (next != EXT_MAX_BLOCKS) {
2043                 ext_debug("next leaf block - %u\n", next);
2044                 BUG_ON(npath != NULL);
2045                 npath = ext4_find_extent(inode, next, NULL, 0);
2046                 if (IS_ERR(npath))
2047                         return PTR_ERR(npath);
2048                 BUG_ON(npath->p_depth != path->p_depth);
2049                 eh = npath[depth].p_hdr;
2050                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2051                         ext_debug("next leaf isn't full(%d)\n",
2052                                   le16_to_cpu(eh->eh_entries));
2053                         path = npath;
2054                         goto has_space;
2055                 }
2056                 ext_debug("next leaf has no free space(%d,%d)\n",
2057                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2058         }
2059
2060         /*
2061          * There is no free space in the found leaf.
2062          * We're gonna add a new leaf in the tree.
2063          */
2064         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2065                 mb_flags |= EXT4_MB_USE_RESERVED;
2066         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2067                                        ppath, newext);
2068         if (err)
2069                 goto cleanup;
2070         depth = ext_depth(inode);
2071         eh = path[depth].p_hdr;
2072
2073 has_space:
2074         nearex = path[depth].p_ext;
2075
2076         err = ext4_ext_get_access(handle, inode, path + depth);
2077         if (err)
2078                 goto cleanup;
2079
2080         if (!nearex) {
2081                 /* there is no extent in this leaf, create first one */
2082                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2083                                 le32_to_cpu(newext->ee_block),
2084                                 ext4_ext_pblock(newext),
2085                                 ext4_ext_is_unwritten(newext),
2086                                 ext4_ext_get_actual_len(newext));
2087                 nearex = EXT_FIRST_EXTENT(eh);
2088         } else {
2089                 if (le32_to_cpu(newext->ee_block)
2090                            > le32_to_cpu(nearex->ee_block)) {
2091                         /* Insert after */
2092                         ext_debug("insert %u:%llu:[%d]%d before: "
2093                                         "nearest %p\n",
2094                                         le32_to_cpu(newext->ee_block),
2095                                         ext4_ext_pblock(newext),
2096                                         ext4_ext_is_unwritten(newext),
2097                                         ext4_ext_get_actual_len(newext),
2098                                         nearex);
2099                         nearex++;
2100                 } else {
2101                         /* Insert before */
2102                         BUG_ON(newext->ee_block == nearex->ee_block);
2103                         ext_debug("insert %u:%llu:[%d]%d after: "
2104                                         "nearest %p\n",
2105                                         le32_to_cpu(newext->ee_block),
2106                                         ext4_ext_pblock(newext),
2107                                         ext4_ext_is_unwritten(newext),
2108                                         ext4_ext_get_actual_len(newext),
2109                                         nearex);
2110                 }
2111                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2112                 if (len > 0) {
2113                         ext_debug("insert %u:%llu:[%d]%d: "
2114                                         "move %d extents from 0x%p to 0x%p\n",
2115                                         le32_to_cpu(newext->ee_block),
2116                                         ext4_ext_pblock(newext),
2117                                         ext4_ext_is_unwritten(newext),
2118                                         ext4_ext_get_actual_len(newext),
2119                                         len, nearex, nearex + 1);
2120                         memmove(nearex + 1, nearex,
2121                                 len * sizeof(struct ext4_extent));
2122                 }
2123         }
2124
2125         le16_add_cpu(&eh->eh_entries, 1);
2126         path[depth].p_ext = nearex;
2127         nearex->ee_block = newext->ee_block;
2128         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2129         nearex->ee_len = newext->ee_len;
2130
2131 merge:
2132         /* try to merge extents */
2133         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2134                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2135
2136
2137         /* time to correct all indexes above */
2138         err = ext4_ext_correct_indexes(handle, inode, path);
2139         if (err)
2140                 goto cleanup;
2141
2142         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2143
2144 cleanup:
2145         ext4_ext_drop_refs(npath);
2146         kfree(npath);
2147         return err;
2148 }
2149
2150 static int ext4_fill_fiemap_extents(struct inode *inode,
2151                                     ext4_lblk_t block, ext4_lblk_t num,
2152                                     struct fiemap_extent_info *fieinfo)
2153 {
2154         struct ext4_ext_path *path = NULL;
2155         struct ext4_extent *ex;
2156         struct extent_status es;
2157         ext4_lblk_t next, next_del, start = 0, end = 0;
2158         ext4_lblk_t last = block + num;
2159         int exists, depth = 0, err = 0;
2160         unsigned int flags = 0;
2161         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2162
2163         while (block < last && block != EXT_MAX_BLOCKS) {
2164                 num = last - block;
2165                 /* find extent for this block */
2166                 down_read(&EXT4_I(inode)->i_data_sem);
2167
2168                 path = ext4_find_extent(inode, block, &path, 0);
2169                 if (IS_ERR(path)) {
2170                         up_read(&EXT4_I(inode)->i_data_sem);
2171                         err = PTR_ERR(path);
2172                         path = NULL;
2173                         break;
2174                 }
2175
2176                 depth = ext_depth(inode);
2177                 if (unlikely(path[depth].p_hdr == NULL)) {
2178                         up_read(&EXT4_I(inode)->i_data_sem);
2179                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2180                         err = -EFSCORRUPTED;
2181                         break;
2182                 }
2183                 ex = path[depth].p_ext;
2184                 next = ext4_ext_next_allocated_block(path);
2185
2186                 flags = 0;
2187                 exists = 0;
2188                 if (!ex) {
2189                         /* there is no extent yet, so try to allocate
2190                          * all requested space */
2191                         start = block;
2192                         end = block + num;
2193                 } else if (le32_to_cpu(ex->ee_block) > block) {
2194                         /* need to allocate space before found extent */
2195                         start = block;
2196                         end = le32_to_cpu(ex->ee_block);
2197                         if (block + num < end)
2198                                 end = block + num;
2199                 } else if (block >= le32_to_cpu(ex->ee_block)
2200                                         + ext4_ext_get_actual_len(ex)) {
2201                         /* need to allocate space after found extent */
2202                         start = block;
2203                         end = block + num;
2204                         if (end >= next)
2205                                 end = next;
2206                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2207                         /*
2208                          * some part of requested space is covered
2209                          * by found extent
2210                          */
2211                         start = block;
2212                         end = le32_to_cpu(ex->ee_block)
2213                                 + ext4_ext_get_actual_len(ex);
2214                         if (block + num < end)
2215                                 end = block + num;
2216                         exists = 1;
2217                 } else {
2218                         BUG();
2219                 }
2220                 BUG_ON(end <= start);
2221
2222                 if (!exists) {
2223                         es.es_lblk = start;
2224                         es.es_len = end - start;
2225                         es.es_pblk = 0;
2226                 } else {
2227                         es.es_lblk = le32_to_cpu(ex->ee_block);
2228                         es.es_len = ext4_ext_get_actual_len(ex);
2229                         es.es_pblk = ext4_ext_pblock(ex);
2230                         if (ext4_ext_is_unwritten(ex))
2231                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2232                 }
2233
2234                 /*
2235                  * Find delayed extent and update es accordingly. We call
2236                  * it even in !exists case to find out whether es is the
2237                  * last existing extent or not.
2238                  */
2239                 next_del = ext4_find_delayed_extent(inode, &es);
2240                 if (!exists && next_del) {
2241                         exists = 1;
2242                         flags |= (FIEMAP_EXTENT_DELALLOC |
2243                                   FIEMAP_EXTENT_UNKNOWN);
2244                 }
2245                 up_read(&EXT4_I(inode)->i_data_sem);
2246
2247                 if (unlikely(es.es_len == 0)) {
2248                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2249                         err = -EFSCORRUPTED;
2250                         break;
2251                 }
2252
2253                 /*
2254                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2255                  * we need to check next == EXT_MAX_BLOCKS because it is
2256                  * possible that an extent is with unwritten and delayed
2257                  * status due to when an extent is delayed allocated and
2258                  * is allocated by fallocate status tree will track both of
2259                  * them in a extent.
2260                  *
2261                  * So we could return a unwritten and delayed extent, and
2262                  * its block is equal to 'next'.
2263                  */
2264                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2265                         flags |= FIEMAP_EXTENT_LAST;
2266                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2267                                      next != EXT_MAX_BLOCKS)) {
2268                                 EXT4_ERROR_INODE(inode,
2269                                                  "next extent == %u, next "
2270                                                  "delalloc extent = %u",
2271                                                  next, next_del);
2272                                 err = -EFSCORRUPTED;
2273                                 break;
2274                         }
2275                 }
2276
2277                 if (exists) {
2278                         err = fiemap_fill_next_extent(fieinfo,
2279                                 (__u64)es.es_lblk << blksize_bits,
2280                                 (__u64)es.es_pblk << blksize_bits,
2281                                 (__u64)es.es_len << blksize_bits,
2282                                 flags);
2283                         if (err < 0)
2284                                 break;
2285                         if (err == 1) {
2286                                 err = 0;
2287                                 break;
2288                         }
2289                 }
2290
2291                 block = es.es_lblk + es.es_len;
2292         }
2293
2294         ext4_ext_drop_refs(path);
2295         kfree(path);
2296         return err;
2297 }
2298
2299 /*
2300  * ext4_ext_put_gap_in_cache:
2301  * calculate boundaries of the gap that the requested block fits into
2302  * and cache this gap
2303  */
2304 static void
2305 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
2306                                 ext4_lblk_t block)
2307 {
2308         int depth = ext_depth(inode);
2309         ext4_lblk_t len;
2310         ext4_lblk_t lblock;
2311         struct ext4_extent *ex;
2312         struct extent_status es;
2313
2314         ex = path[depth].p_ext;
2315         if (ex == NULL) {
2316                 /* there is no extent yet, so gap is [0;-] */
2317                 lblock = 0;
2318                 len = EXT_MAX_BLOCKS;
2319                 ext_debug("cache gap(whole file):");
2320         } else if (block < le32_to_cpu(ex->ee_block)) {
2321                 lblock = block;
2322                 len = le32_to_cpu(ex->ee_block) - block;
2323                 ext_debug("cache gap(before): %u [%u:%u]",
2324                                 block,
2325                                 le32_to_cpu(ex->ee_block),
2326                                  ext4_ext_get_actual_len(ex));
2327         } else if (block >= le32_to_cpu(ex->ee_block)
2328                         + ext4_ext_get_actual_len(ex)) {
2329                 ext4_lblk_t next;
2330                 lblock = le32_to_cpu(ex->ee_block)
2331                         + ext4_ext_get_actual_len(ex);
2332
2333                 next = ext4_ext_next_allocated_block(path);
2334                 ext_debug("cache gap(after): [%u:%u] %u",
2335                                 le32_to_cpu(ex->ee_block),
2336                                 ext4_ext_get_actual_len(ex),
2337                                 block);
2338                 BUG_ON(next == lblock);
2339                 len = next - lblock;
2340         } else {
2341                 BUG();
2342         }
2343
2344         ext4_es_find_delayed_extent_range(inode, lblock, lblock + len - 1, &es);
2345         if (es.es_len) {
2346                 /* There's delayed extent containing lblock? */
2347                 if (es.es_lblk <= lblock)
2348                         return;
2349                 len = min(es.es_lblk - lblock, len);
2350         }
2351         ext_debug(" -> %u:%u\n", lblock, len);
2352         ext4_es_insert_extent(inode, lblock, len, ~0, EXTENT_STATUS_HOLE);
2353 }
2354
2355 /*
2356  * ext4_ext_rm_idx:
2357  * removes index from the index block.
2358  */
2359 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2360                         struct ext4_ext_path *path, int depth)
2361 {
2362         int err;
2363         ext4_fsblk_t leaf;
2364
2365         /* free index block */
2366         depth--;
2367         path = path + depth;
2368         leaf = ext4_idx_pblock(path->p_idx);
2369         if (unlikely(path->p_hdr->eh_entries == 0)) {
2370                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2371                 return -EFSCORRUPTED;
2372         }
2373         err = ext4_ext_get_access(handle, inode, path);
2374         if (err)
2375                 return err;
2376
2377         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2378                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2379                 len *= sizeof(struct ext4_extent_idx);
2380                 memmove(path->p_idx, path->p_idx + 1, len);
2381         }
2382
2383         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2384         err = ext4_ext_dirty(handle, inode, path);
2385         if (err)
2386                 return err;
2387         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2388         trace_ext4_ext_rm_idx(inode, leaf);
2389
2390         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2391                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2392
2393         while (--depth >= 0) {
2394                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2395                         break;
2396                 path--;
2397                 err = ext4_ext_get_access(handle, inode, path);
2398                 if (err)
2399                         break;
2400                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2401                 err = ext4_ext_dirty(handle, inode, path);
2402                 if (err)
2403                         break;
2404         }
2405         return err;
2406 }
2407
2408 /*
2409  * ext4_ext_calc_credits_for_single_extent:
2410  * This routine returns max. credits that needed to insert an extent
2411  * to the extent tree.
2412  * When pass the actual path, the caller should calculate credits
2413  * under i_data_sem.
2414  */
2415 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2416                                                 struct ext4_ext_path *path)
2417 {
2418         if (path) {
2419                 int depth = ext_depth(inode);
2420                 int ret = 0;
2421
2422                 /* probably there is space in leaf? */
2423                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2424                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2425
2426                         /*
2427                          *  There are some space in the leaf tree, no
2428                          *  need to account for leaf block credit
2429                          *
2430                          *  bitmaps and block group descriptor blocks
2431                          *  and other metadata blocks still need to be
2432                          *  accounted.
2433                          */
2434                         /* 1 bitmap, 1 block group descriptor */
2435                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2436                         return ret;
2437                 }
2438         }
2439
2440         return ext4_chunk_trans_blocks(inode, nrblocks);
2441 }
2442
2443 /*
2444  * How many index/leaf blocks need to change/allocate to add @extents extents?
2445  *
2446  * If we add a single extent, then in the worse case, each tree level
2447  * index/leaf need to be changed in case of the tree split.
2448  *
2449  * If more extents are inserted, they could cause the whole tree split more
2450  * than once, but this is really rare.
2451  */
2452 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2453 {
2454         int index;
2455         int depth;
2456
2457         /* If we are converting the inline data, only one is needed here. */
2458         if (ext4_has_inline_data(inode))
2459                 return 1;
2460
2461         depth = ext_depth(inode);
2462
2463         if (extents <= 1)
2464                 index = depth * 2;
2465         else
2466                 index = depth * 3;
2467
2468         return index;
2469 }
2470
2471 static inline int get_default_free_blocks_flags(struct inode *inode)
2472 {
2473         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2474                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2475         else if (ext4_should_journal_data(inode))
2476                 return EXT4_FREE_BLOCKS_FORGET;
2477         return 0;
2478 }
2479
2480 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2481                               struct ext4_extent *ex,
2482                               long long *partial_cluster,
2483                               ext4_lblk_t from, ext4_lblk_t to)
2484 {
2485         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2486         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2487         ext4_fsblk_t pblk;
2488         int flags = get_default_free_blocks_flags(inode);
2489
2490         /*
2491          * For bigalloc file systems, we never free a partial cluster
2492          * at the beginning of the extent.  Instead, we make a note
2493          * that we tried freeing the cluster, and check to see if we
2494          * need to free it on a subsequent call to ext4_remove_blocks,
2495          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2496          */
2497         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2498
2499         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2500         /*
2501          * If we have a partial cluster, and it's different from the
2502          * cluster of the last block, we need to explicitly free the
2503          * partial cluster here.
2504          */
2505         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2506         if (*partial_cluster > 0 &&
2507             *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2508                 ext4_free_blocks(handle, inode, NULL,
2509                                  EXT4_C2B(sbi, *partial_cluster),
2510                                  sbi->s_cluster_ratio, flags);
2511                 *partial_cluster = 0;
2512         }
2513
2514 #ifdef EXTENTS_STATS
2515         {
2516                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2517                 spin_lock(&sbi->s_ext_stats_lock);
2518                 sbi->s_ext_blocks += ee_len;
2519                 sbi->s_ext_extents++;
2520                 if (ee_len < sbi->s_ext_min)
2521                         sbi->s_ext_min = ee_len;
2522                 if (ee_len > sbi->s_ext_max)
2523                         sbi->s_ext_max = ee_len;
2524                 if (ext_depth(inode) > sbi->s_depth_max)
2525                         sbi->s_depth_max = ext_depth(inode);
2526                 spin_unlock(&sbi->s_ext_stats_lock);
2527         }
2528 #endif
2529         if (from >= le32_to_cpu(ex->ee_block)
2530             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2531                 /* tail removal */
2532                 ext4_lblk_t num;
2533                 long long first_cluster;
2534
2535                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2536                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2537                 /*
2538                  * Usually we want to free partial cluster at the end of the
2539                  * extent, except for the situation when the cluster is still
2540                  * used by any other extent (partial_cluster is negative).
2541                  */
2542                 if (*partial_cluster < 0 &&
2543                     *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))
2544                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2545
2546                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2547                           num, pblk, *partial_cluster);
2548                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2549                 /*
2550                  * If the block range to be freed didn't start at the
2551                  * beginning of a cluster, and we removed the entire
2552                  * extent and the cluster is not used by any other extent,
2553                  * save the partial cluster here, since we might need to
2554                  * delete if we determine that the truncate or punch hole
2555                  * operation has removed all of the blocks in the cluster.
2556                  * If that cluster is used by another extent, preserve its
2557                  * negative value so it isn't freed later on.
2558                  *
2559                  * If the whole extent wasn't freed, we've reached the
2560                  * start of the truncated/punched region and have finished
2561                  * removing blocks.  If there's a partial cluster here it's
2562                  * shared with the remainder of the extent and is no longer
2563                  * a candidate for removal.
2564                  */
2565                 if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {
2566                         first_cluster = (long long) EXT4_B2C(sbi, pblk);
2567                         if (first_cluster != -*partial_cluster)
2568                                 *partial_cluster = first_cluster;
2569                 } else {
2570                         *partial_cluster = 0;
2571                 }
2572         } else
2573                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2574                            "%u-%u from %u:%u\n",
2575                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2576         return 0;
2577 }
2578
2579
2580 /*
2581  * ext4_ext_rm_leaf() Removes the extents associated with the
2582  * blocks appearing between "start" and "end".  Both "start"
2583  * and "end" must appear in the same extent or EIO is returned.
2584  *
2585  * @handle: The journal handle
2586  * @inode:  The files inode
2587  * @path:   The path to the leaf
2588  * @partial_cluster: The cluster which we'll have to free if all extents
2589  *                   has been released from it.  However, if this value is
2590  *                   negative, it's a cluster just to the right of the
2591  *                   punched region and it must not be freed.
2592  * @start:  The first block to remove
2593  * @end:   The last block to remove
2594  */
2595 static int
2596 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2597                  struct ext4_ext_path *path,
2598                  long long *partial_cluster,
2599                  ext4_lblk_t start, ext4_lblk_t end)
2600 {
2601         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2602         int err = 0, correct_index = 0;
2603         int depth = ext_depth(inode), credits;
2604         struct ext4_extent_header *eh;
2605         ext4_lblk_t a, b;
2606         unsigned num;
2607         ext4_lblk_t ex_ee_block;
2608         unsigned short ex_ee_len;
2609         unsigned unwritten = 0;
2610         struct ext4_extent *ex;
2611         ext4_fsblk_t pblk;
2612
2613         /* the header must be checked already in ext4_ext_remove_space() */
2614         ext_debug("truncate since %u in leaf to %u\n", start, end);
2615         if (!path[depth].p_hdr)
2616                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2617         eh = path[depth].p_hdr;
2618         if (unlikely(path[depth].p_hdr == NULL)) {
2619                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2620                 return -EFSCORRUPTED;
2621         }
2622         /* find where to start removing */
2623         ex = path[depth].p_ext;
2624         if (!ex)
2625                 ex = EXT_LAST_EXTENT(eh);
2626
2627         ex_ee_block = le32_to_cpu(ex->ee_block);
2628         ex_ee_len = ext4_ext_get_actual_len(ex);
2629
2630         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2631
2632         while (ex >= EXT_FIRST_EXTENT(eh) &&
2633                         ex_ee_block + ex_ee_len > start) {
2634
2635                 if (ext4_ext_is_unwritten(ex))
2636                         unwritten = 1;
2637                 else
2638                         unwritten = 0;
2639
2640                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2641                           unwritten, ex_ee_len);
2642                 path[depth].p_ext = ex;
2643
2644                 a = ex_ee_block > start ? ex_ee_block : start;
2645                 b = ex_ee_block+ex_ee_len - 1 < end ?
2646                         ex_ee_block+ex_ee_len - 1 : end;
2647
2648                 ext_debug("  border %u:%u\n", a, b);
2649
2650                 /* If this extent is beyond the end of the hole, skip it */
2651                 if (end < ex_ee_block) {
2652                         /*
2653                          * We're going to skip this extent and move to another,
2654                          * so note that its first cluster is in use to avoid
2655                          * freeing it when removing blocks.  Eventually, the
2656                          * right edge of the truncated/punched region will
2657                          * be just to the left.
2658                          */
2659                         if (sbi->s_cluster_ratio > 1) {
2660                                 pblk = ext4_ext_pblock(ex);
2661                                 *partial_cluster =
2662                                         -(long long) EXT4_B2C(sbi, pblk);
2663                         }
2664                         ex--;
2665                         ex_ee_block = le32_to_cpu(ex->ee_block);
2666                         ex_ee_len = ext4_ext_get_actual_len(ex);
2667                         continue;
2668                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2669                         EXT4_ERROR_INODE(inode,
2670                                          "can not handle truncate %u:%u "
2671                                          "on extent %u:%u",
2672                                          start, end, ex_ee_block,
2673                                          ex_ee_block + ex_ee_len - 1);
2674                         err = -EFSCORRUPTED;
2675                         goto out;
2676                 } else if (a != ex_ee_block) {
2677                         /* remove tail of the extent */
2678                         num = a - ex_ee_block;
2679                 } else {
2680                         /* remove whole extent: excellent! */
2681                         num = 0;
2682                 }
2683                 /*
2684                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2685                  * descriptor) for each block group; assume two block
2686                  * groups plus ex_ee_len/blocks_per_block_group for
2687                  * the worst case
2688                  */
2689                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2690                 if (ex == EXT_FIRST_EXTENT(eh)) {
2691                         correct_index = 1;
2692                         credits += (ext_depth(inode)) + 1;
2693                 }
2694                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2695
2696                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2697                 if (err)
2698                         goto out;
2699
2700                 err = ext4_ext_get_access(handle, inode, path + depth);
2701                 if (err)
2702                         goto out;
2703
2704                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2705                                          a, b);
2706                 if (err)
2707                         goto out;
2708
2709                 if (num == 0)
2710                         /* this extent is removed; mark slot entirely unused */
2711                         ext4_ext_store_pblock(ex, 0);
2712
2713                 ex->ee_len = cpu_to_le16(num);
2714                 /*
2715                  * Do not mark unwritten if all the blocks in the
2716                  * extent have been removed.
2717                  */
2718                 if (unwritten && num)
2719                         ext4_ext_mark_unwritten(ex);
2720                 /*
2721                  * If the extent was completely released,
2722                  * we need to remove it from the leaf
2723                  */
2724                 if (num == 0) {
2725                         if (end != EXT_MAX_BLOCKS - 1) {
2726                                 /*
2727                                  * For hole punching, we need to scoot all the
2728                                  * extents up when an extent is removed so that
2729                                  * we dont have blank extents in the middle
2730                                  */
2731                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2732                                         sizeof(struct ext4_extent));
2733
2734                                 /* Now get rid of the one at the end */
2735                                 memset(EXT_LAST_EXTENT(eh), 0,
2736                                         sizeof(struct ext4_extent));
2737                         }
2738                         le16_add_cpu(&eh->eh_entries, -1);
2739                 }
2740
2741                 err = ext4_ext_dirty(handle, inode, path + depth);
2742                 if (err)
2743                         goto out;
2744
2745                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2746                                 ext4_ext_pblock(ex));
2747                 ex--;
2748                 ex_ee_block = le32_to_cpu(ex->ee_block);
2749                 ex_ee_len = ext4_ext_get_actual_len(ex);
2750         }
2751
2752         if (correct_index && eh->eh_entries)
2753                 err = ext4_ext_correct_indexes(handle, inode, path);
2754
2755         /*
2756          * If there's a partial cluster and at least one extent remains in
2757          * the leaf, free the partial cluster if it isn't shared with the
2758          * current extent.  If it is shared with the current extent
2759          * we zero partial_cluster because we've reached the start of the
2760          * truncated/punched region and we're done removing blocks.
2761          */
2762         if (*partial_cluster > 0 && ex >= EXT_FIRST_EXTENT(eh)) {
2763                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2764                 if (*partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2765                         ext4_free_blocks(handle, inode, NULL,
2766                                          EXT4_C2B(sbi, *partial_cluster),
2767                                          sbi->s_cluster_ratio,
2768                                          get_default_free_blocks_flags(inode));
2769                 }
2770                 *partial_cluster = 0;
2771         }
2772
2773         /* if this leaf is free, then we should
2774          * remove it from index block above */
2775         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2776                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2777
2778 out:
2779         return err;
2780 }
2781
2782 /*
2783  * ext4_ext_more_to_rm:
2784  * returns 1 if current index has to be freed (even partial)
2785  */
2786 static int
2787 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2788 {
2789         BUG_ON(path->p_idx == NULL);
2790
2791         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2792                 return 0;
2793
2794         /*
2795          * if truncate on deeper level happened, it wasn't partial,
2796          * so we have to consider current index for truncation
2797          */
2798         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2799                 return 0;
2800         return 1;
2801 }
2802
2803 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2804                           ext4_lblk_t end)
2805 {
2806         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2807         int depth = ext_depth(inode);
2808         struct ext4_ext_path *path = NULL;
2809         long long partial_cluster = 0;
2810         handle_t *handle;
2811         int i = 0, err = 0;
2812
2813         ext_debug("truncate since %u to %u\n", start, end);
2814
2815         /* probably first extent we're gonna free will be last in block */
2816         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2817         if (IS_ERR(handle))
2818                 return PTR_ERR(handle);
2819
2820 again:
2821         trace_ext4_ext_remove_space(inode, start, end, depth);
2822
2823         /*
2824          * Check if we are removing extents inside the extent tree. If that
2825          * is the case, we are going to punch a hole inside the extent tree
2826          * so we have to check whether we need to split the extent covering
2827          * the last block to remove so we can easily remove the part of it
2828          * in ext4_ext_rm_leaf().
2829          */
2830         if (end < EXT_MAX_BLOCKS - 1) {
2831                 struct ext4_extent *ex;
2832                 ext4_lblk_t ee_block, ex_end, lblk;
2833                 ext4_fsblk_t pblk;
2834
2835                 /* find extent for or closest extent to this block */
2836                 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2837                 if (IS_ERR(path)) {
2838                         ext4_journal_stop(handle);
2839                         return PTR_ERR(path);
2840                 }
2841                 depth = ext_depth(inode);
2842                 /* Leaf not may not exist only if inode has no blocks at all */
2843                 ex = path[depth].p_ext;
2844                 if (!ex) {
2845                         if (depth) {
2846                                 EXT4_ERROR_INODE(inode,
2847                                                  "path[%d].p_hdr == NULL",
2848                                                  depth);
2849                                 err = -EFSCORRUPTED;
2850                         }
2851                         goto out;
2852                 }
2853
2854                 ee_block = le32_to_cpu(ex->ee_block);
2855                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2856
2857                 /*
2858                  * See if the last block is inside the extent, if so split
2859                  * the extent at 'end' block so we can easily remove the
2860                  * tail of the first part of the split extent in
2861                  * ext4_ext_rm_leaf().
2862                  */
2863                 if (end >= ee_block && end < ex_end) {
2864
2865                         /*
2866                          * If we're going to split the extent, note that
2867                          * the cluster containing the block after 'end' is
2868                          * in use to avoid freeing it when removing blocks.
2869                          */
2870                         if (sbi->s_cluster_ratio > 1) {
2871                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2872                                 partial_cluster =
2873                                         -(long long) EXT4_B2C(sbi, pblk);
2874                         }
2875
2876                         /*
2877                          * Split the extent in two so that 'end' is the last
2878                          * block in the first new extent. Also we should not
2879                          * fail removing space due to ENOSPC so try to use
2880                          * reserved block if that happens.
2881                          */
2882                         err = ext4_force_split_extent_at(handle, inode, &path,
2883                                                          end + 1, 1);
2884                         if (err < 0)
2885                                 goto out;
2886
2887                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end) {
2888                         /*
2889                          * If there's an extent to the right its first cluster
2890                          * contains the immediate right boundary of the
2891                          * truncated/punched region.  Set partial_cluster to
2892                          * its negative value so it won't be freed if shared
2893                          * with the current extent.  The end < ee_block case
2894                          * is handled in ext4_ext_rm_leaf().
2895                          */
2896                         lblk = ex_end + 1;
2897                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2898                                                     &ex);
2899                         if (err)
2900                                 goto out;
2901                         if (pblk)
2902                                 partial_cluster =
2903                                         -(long long) EXT4_B2C(sbi, pblk);
2904                 }
2905         }
2906         /*
2907          * We start scanning from right side, freeing all the blocks
2908          * after i_size and walking into the tree depth-wise.
2909          */
2910         depth = ext_depth(inode);
2911         if (path) {
2912                 int k = i = depth;
2913                 while (--k > 0)
2914                         path[k].p_block =
2915                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2916         } else {
2917                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2918                                GFP_NOFS);
2919                 if (path == NULL) {
2920                         ext4_journal_stop(handle);
2921                         return -ENOMEM;
2922                 }
2923                 path[0].p_maxdepth = path[0].p_depth = depth;
2924                 path[0].p_hdr = ext_inode_hdr(inode);
2925                 i = 0;
2926
2927                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2928                         err = -EFSCORRUPTED;
2929                         goto out;
2930                 }
2931         }
2932         err = 0;
2933
2934         while (i >= 0 && err == 0) {
2935                 if (i == depth) {
2936                         /* this is leaf block */
2937                         err = ext4_ext_rm_leaf(handle, inode, path,
2938                                                &partial_cluster, start,
2939                                                end);
2940                         /* root level has p_bh == NULL, brelse() eats this */
2941                         brelse(path[i].p_bh);
2942                         path[i].p_bh = NULL;
2943                         i--;
2944                         continue;
2945                 }
2946
2947                 /* this is index block */
2948                 if (!path[i].p_hdr) {
2949                         ext_debug("initialize header\n");
2950                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2951                 }
2952
2953                 if (!path[i].p_idx) {
2954                         /* this level hasn't been touched yet */
2955                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2956                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2957                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2958                                   path[i].p_hdr,
2959                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2960                 } else {
2961                         /* we were already here, see at next index */
2962                         path[i].p_idx--;
2963                 }
2964
2965                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2966                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2967                                 path[i].p_idx);
2968                 if (ext4_ext_more_to_rm(path + i)) {
2969                         struct buffer_head *bh;
2970                         /* go to the next level */
2971                         ext_debug("move to level %d (block %llu)\n",
2972                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2973                         memset(path + i + 1, 0, sizeof(*path));
2974                         bh = read_extent_tree_block(inode,
2975                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2976                                 EXT4_EX_NOCACHE);
2977                         if (IS_ERR(bh)) {
2978                                 /* should we reset i_size? */
2979                                 err = PTR_ERR(bh);
2980                                 break;
2981                         }
2982                         /* Yield here to deal with large extent trees.
2983                          * Should be a no-op if we did IO above. */
2984                         cond_resched();
2985                         if (WARN_ON(i + 1 > depth)) {
2986                                 err = -EFSCORRUPTED;
2987                                 break;
2988                         }
2989                         path[i + 1].p_bh = bh;
2990
2991                         /* save actual number of indexes since this
2992                          * number is changed at the next iteration */
2993                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2994                         i++;
2995                 } else {
2996                         /* we finished processing this index, go up */
2997                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2998                                 /* index is empty, remove it;
2999                                  * handle must be already prepared by the
3000                                  * truncatei_leaf() */
3001                                 err = ext4_ext_rm_idx(handle, inode, path, i);
3002                         }
3003                         /* root level has p_bh == NULL, brelse() eats this */
3004                         brelse(path[i].p_bh);
3005                         path[i].p_bh = NULL;
3006                         i--;
3007                         ext_debug("return to level %d\n", i);
3008                 }
3009         }
3010
3011         trace_ext4_ext_remove_space_done(inode, start, end, depth,
3012                         partial_cluster, path->p_hdr->eh_entries);
3013
3014         /*
3015          * If we still have something in the partial cluster and we have removed
3016          * even the first extent, then we should free the blocks in the partial
3017          * cluster as well.  (This code will only run when there are no leaves
3018          * to the immediate left of the truncated/punched region.)
3019          */
3020         if (partial_cluster > 0 && err == 0) {
3021                 /* don't zero partial_cluster since it's not used afterwards */
3022                 ext4_free_blocks(handle, inode, NULL,
3023                                  EXT4_C2B(sbi, partial_cluster),
3024                                  sbi->s_cluster_ratio,
3025                                  get_default_free_blocks_flags(inode));
3026         }
3027
3028         /* TODO: flexible tree reduction should be here */
3029         if (path->p_hdr->eh_entries == 0) {
3030                 /*
3031                  * truncate to zero freed all the tree,
3032                  * so we need to correct eh_depth
3033                  */
3034                 err = ext4_ext_get_access(handle, inode, path);
3035                 if (err == 0) {
3036                         ext_inode_hdr(inode)->eh_depth = 0;
3037                         ext_inode_hdr(inode)->eh_max =
3038                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3039                         err = ext4_ext_dirty(handle, inode, path);
3040                 }
3041         }
3042 out:
3043         ext4_ext_drop_refs(path);
3044         kfree(path);
3045         path = NULL;
3046         if (err == -EAGAIN)
3047                 goto again;
3048         ext4_journal_stop(handle);
3049
3050         return err;
3051 }
3052
3053 /*
3054  * called at mount time
3055  */
3056 void ext4_ext_init(struct super_block *sb)
3057 {
3058         /*
3059          * possible initialization would be here
3060          */
3061
3062         if (ext4_has_feature_extents(sb)) {
3063 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3064                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3065 #ifdef AGGRESSIVE_TEST
3066                        ", aggressive tests"
3067 #endif
3068 #ifdef CHECK_BINSEARCH
3069                        ", check binsearch"
3070 #endif
3071 #ifdef EXTENTS_STATS
3072                        ", stats"
3073 #endif
3074                        "\n");
3075 #endif
3076 #ifdef EXTENTS_STATS
3077                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3078                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3079                 EXT4_SB(sb)->s_ext_max = 0;
3080 #endif
3081         }
3082 }
3083
3084 /*
3085  * called at umount time
3086  */
3087 void ext4_ext_release(struct super_block *sb)
3088 {
3089         if (!ext4_has_feature_extents(sb))
3090                 return;
3091
3092 #ifdef EXTENTS_STATS
3093         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3094                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3095                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3096                         sbi->s_ext_blocks, sbi->s_ext_extents,
3097                         sbi->s_ext_blocks / sbi->s_ext_extents);
3098                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3099                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3100         }
3101 #endif
3102 }
3103
3104 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3105 {
3106         ext4_lblk_t  ee_block;
3107         ext4_fsblk_t ee_pblock;
3108         unsigned int ee_len;
3109
3110         ee_block  = le32_to_cpu(ex->ee_block);
3111         ee_len    = ext4_ext_get_actual_len(ex);
3112         ee_pblock = ext4_ext_pblock(ex);
3113
3114         if (ee_len == 0)
3115                 return 0;
3116
3117         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3118                                      EXTENT_STATUS_WRITTEN);
3119 }
3120
3121 /* FIXME!! we need to try to merge to left or right after zero-out  */
3122 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3123 {
3124         ext4_fsblk_t ee_pblock;
3125         unsigned int ee_len;
3126         int ret;
3127
3128         ee_len    = ext4_ext_get_actual_len(ex);
3129         ee_pblock = ext4_ext_pblock(ex);
3130
3131         if (ext4_encrypted_inode(inode))
3132                 return ext4_encrypted_zeroout(inode, ex);
3133
3134         ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
3135         if (ret > 0)
3136                 ret = 0;
3137
3138         return ret;
3139 }
3140
3141 /*
3142  * ext4_split_extent_at() splits an extent at given block.
3143  *
3144  * @handle: the journal handle
3145  * @inode: the file inode
3146  * @path: the path to the extent
3147  * @split: the logical block where the extent is splitted.
3148  * @split_flags: indicates if the extent could be zeroout if split fails, and
3149  *               the states(init or unwritten) of new extents.
3150  * @flags: flags used to insert new extent to extent tree.
3151  *
3152  *
3153  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3154  * of which are deterimined by split_flag.
3155  *
3156  * There are two cases:
3157  *  a> the extent are splitted into two extent.
3158  *  b> split is not needed, and just mark the extent.
3159  *
3160  * return 0 on success.
3161  */
3162 static int ext4_split_extent_at(handle_t *handle,
3163                              struct inode *inode,
3164                              struct ext4_ext_path **ppath,
3165                              ext4_lblk_t split,
3166                              int split_flag,
3167                              int flags)
3168 {
3169         struct ext4_ext_path *path = *ppath;
3170         ext4_fsblk_t newblock;
3171         ext4_lblk_t ee_block;
3172         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3173         struct ext4_extent *ex2 = NULL;
3174         unsigned int ee_len, depth;
3175         int err = 0;
3176
3177         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3178                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3179
3180         ext_debug("ext4_split_extents_at: inode %lu, logical"
3181                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3182
3183         ext4_ext_show_leaf(inode, path);
3184
3185         depth = ext_depth(inode);
3186         ex = path[depth].p_ext;
3187         ee_block = le32_to_cpu(ex->ee_block);
3188         ee_len = ext4_ext_get_actual_len(ex);
3189         newblock = split - ee_block + ext4_ext_pblock(ex);
3190
3191         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3192         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3193                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3194                              EXT4_EXT_MARK_UNWRIT1 |
3195                              EXT4_EXT_MARK_UNWRIT2));
3196
3197         err = ext4_ext_get_access(handle, inode, path + depth);
3198         if (err)
3199                 goto out;
3200
3201         if (split == ee_block) {
3202                 /*
3203                  * case b: block @split is the block that the extent begins with
3204                  * then we just change the state of the extent, and splitting
3205                  * is not needed.
3206                  */
3207                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3208                         ext4_ext_mark_unwritten(ex);
3209                 else
3210                         ext4_ext_mark_initialized(ex);
3211
3212                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3213                         ext4_ext_try_to_merge(handle, inode, path, ex);
3214
3215                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3216                 goto out;
3217         }
3218
3219         /* case a */
3220         memcpy(&orig_ex, ex, sizeof(orig_ex));
3221         ex->ee_len = cpu_to_le16(split - ee_block);
3222         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3223                 ext4_ext_mark_unwritten(ex);
3224
3225         /*
3226          * path may lead to new leaf, not to original leaf any more
3227          * after ext4_ext_insert_extent() returns,
3228          */
3229         err = ext4_ext_dirty(handle, inode, path + depth);
3230         if (err)
3231                 goto fix_extent_len;
3232
3233         ex2 = &newex;
3234         ex2->ee_block = cpu_to_le32(split);
3235         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3236         ext4_ext_store_pblock(ex2, newblock);
3237         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3238                 ext4_ext_mark_unwritten(ex2);
3239
3240         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3241         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3242                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3243                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3244                                 err = ext4_ext_zeroout(inode, ex2);
3245                                 zero_ex.ee_block = ex2->ee_block;
3246                                 zero_ex.ee_len = cpu_to_le16(
3247                                                 ext4_ext_get_actual_len(ex2));
3248                                 ext4_ext_store_pblock(&zero_ex,
3249                                                       ext4_ext_pblock(ex2));
3250                         } else {
3251                                 err = ext4_ext_zeroout(inode, ex);
3252                                 zero_ex.ee_block = ex->ee_block;
3253                                 zero_ex.ee_len = cpu_to_le16(
3254                                                 ext4_ext_get_actual_len(ex));
3255                                 ext4_ext_store_pblock(&zero_ex,
3256                                                       ext4_ext_pblock(ex));
3257                         }
3258                 } else {
3259                         err = ext4_ext_zeroout(inode, &orig_ex);
3260                         zero_ex.ee_block = orig_ex.ee_block;
3261                         zero_ex.ee_len = cpu_to_le16(
3262                                                 ext4_ext_get_actual_len(&orig_ex));
3263                         ext4_ext_store_pblock(&zero_ex,
3264                                               ext4_ext_pblock(&orig_ex));
3265                 }
3266
3267                 if (err)
3268                         goto fix_extent_len;
3269                 /* update the extent length and mark as initialized */
3270                 ex->ee_len = cpu_to_le16(ee_len);
3271                 ext4_ext_try_to_merge(handle, inode, path, ex);
3272                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3273                 if (err)
3274                         goto fix_extent_len;
3275
3276                 /* update extent status tree */
3277                 err = ext4_zeroout_es(inode, &zero_ex);
3278
3279                 goto out;
3280         } else if (err)
3281                 goto fix_extent_len;
3282
3283 out:
3284         ext4_ext_show_leaf(inode, path);
3285         return err;
3286
3287 fix_extent_len:
3288         ex->ee_len = orig_ex.ee_len;
3289         ext4_ext_dirty(handle, inode, path + path->p_depth);
3290         return err;
3291 }
3292
3293 /*
3294  * ext4_split_extents() splits an extent and mark extent which is covered
3295  * by @map as split_flags indicates
3296  *
3297  * It may result in splitting the extent into multiple extents (up to three)
3298  * There are three possibilities:
3299  *   a> There is no split required
3300  *   b> Splits in two extents: Split is happening at either end of the extent
3301  *   c> Splits in three extents: Somone is splitting in middle of the extent
3302  *
3303  */
3304 static int ext4_split_extent(handle_t *handle,
3305                               struct inode *inode,
3306                               struct ext4_ext_path **ppath,
3307                               struct ext4_map_blocks *map,
3308                               int split_flag,
3309                               int flags)
3310 {
3311         struct ext4_ext_path *path = *ppath;
3312         ext4_lblk_t ee_block;
3313         struct ext4_extent *ex;
3314         unsigned int ee_len, depth;
3315         int err = 0;
3316         int unwritten;
3317         int split_flag1, flags1;
3318         int allocated = map->m_len;
3319
3320         depth = ext_depth(inode);
3321         ex = path[depth].p_ext;
3322         ee_block = le32_to_cpu(ex->ee_block);
3323         ee_len = ext4_ext_get_actual_len(ex);
3324         unwritten = ext4_ext_is_unwritten(ex);
3325
3326         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3327                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3328                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3329                 if (unwritten)
3330                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3331                                        EXT4_EXT_MARK_UNWRIT2;
3332                 if (split_flag & EXT4_EXT_DATA_VALID2)
3333                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3334                 err = ext4_split_extent_at(handle, inode, ppath,
3335                                 map->m_lblk + map->m_len, split_flag1, flags1);
3336                 if (err)
3337                         goto out;
3338         } else {
3339                 allocated = ee_len - (map->m_lblk - ee_block);
3340         }
3341         /*
3342          * Update path is required because previous ext4_split_extent_at() may
3343          * result in split of original leaf or extent zeroout.
3344          */
3345         path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3346         if (IS_ERR(path))
3347                 return PTR_ERR(path);
3348         depth = ext_depth(inode);
3349         ex = path[depth].p_ext;
3350         if (!ex) {
3351                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3352                                  (unsigned long) map->m_lblk);
3353                 return -EFSCORRUPTED;
3354         }
3355         unwritten = ext4_ext_is_unwritten(ex);
3356         split_flag1 = 0;
3357
3358         if (map->m_lblk >= ee_block) {
3359                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3360                 if (unwritten) {
3361                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3362                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3363                                                      EXT4_EXT_MARK_UNWRIT2);
3364                 }
3365                 err = ext4_split_extent_at(handle, inode, ppath,
3366                                 map->m_lblk, split_flag1, flags);
3367                 if (err)
3368                         goto out;
3369         }
3370
3371         ext4_ext_show_leaf(inode, path);
3372 out:
3373         return err ? err : allocated;
3374 }
3375
3376 /*
3377  * This function is called by ext4_ext_map_blocks() if someone tries to write
3378  * to an unwritten extent. It may result in splitting the unwritten
3379  * extent into multiple extents (up to three - one initialized and two
3380  * unwritten).
3381  * There are three possibilities:
3382  *   a> There is no split required: Entire extent should be initialized
3383  *   b> Splits in two extents: Write is happening at either end of the extent
3384  *   c> Splits in three extents: Somone is writing in middle of the extent
3385  *
3386  * Pre-conditions:
3387  *  - The extent pointed to by 'path' is unwritten.
3388  *  - The extent pointed to by 'path' contains a superset
3389  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3390  *
3391  * Post-conditions on success:
3392  *  - the returned value is the number of blocks beyond map->l_lblk
3393  *    that are allocated and initialized.
3394  *    It is guaranteed to be >= map->m_len.
3395  */
3396 static int ext4_ext_convert_to_initialized(handle_t *handle,
3397                                            struct inode *inode,
3398                                            struct ext4_map_blocks *map,
3399                                            struct ext4_ext_path **ppath,
3400                                            int flags)
3401 {
3402         struct ext4_ext_path *path = *ppath;
3403         struct ext4_sb_info *sbi;
3404         struct ext4_extent_header *eh;
3405         struct ext4_map_blocks split_map;
3406         struct ext4_extent zero_ex;
3407         struct ext4_extent *ex, *abut_ex;
3408         ext4_lblk_t ee_block, eof_block;
3409         unsigned int ee_len, depth, map_len = map->m_len;
3410         int allocated = 0, max_zeroout = 0;
3411         int err = 0;
3412         int split_flag = 0;
3413
3414         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3415                 "block %llu, max_blocks %u\n", inode->i_ino,
3416                 (unsigned long long)map->m_lblk, map_len);
3417
3418         sbi = EXT4_SB(inode->i_sb);
3419         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3420                 inode->i_sb->s_blocksize_bits;
3421         if (eof_block < map->m_lblk + map_len)
3422                 eof_block = map->m_lblk + map_len;
3423
3424         depth = ext_depth(inode);
3425         eh = path[depth].p_hdr;
3426         ex = path[depth].p_ext;
3427         ee_block = le32_to_cpu(ex->ee_block);
3428         ee_len = ext4_ext_get_actual_len(ex);
3429         zero_ex.ee_len = 0;
3430
3431         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3432
3433         /* Pre-conditions */
3434         BUG_ON(!ext4_ext_is_unwritten(ex));
3435         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3436
3437         /*
3438          * Attempt to transfer newly initialized blocks from the currently
3439          * unwritten extent to its neighbor. This is much cheaper
3440          * than an insertion followed by a merge as those involve costly
3441          * memmove() calls. Transferring to the left is the common case in
3442          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3443          * followed by append writes.
3444          *
3445          * Limitations of the current logic:
3446          *  - L1: we do not deal with writes covering the whole extent.
3447          *    This would require removing the extent if the transfer
3448          *    is possible.
3449          *  - L2: we only attempt to merge with an extent stored in the
3450          *    same extent tree node.
3451          */
3452         if ((map->m_lblk == ee_block) &&
3453                 /* See if we can merge left */
3454                 (map_len < ee_len) &&           /*L1*/
3455                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3456                 ext4_lblk_t prev_lblk;
3457                 ext4_fsblk_t prev_pblk, ee_pblk;
3458                 unsigned int prev_len;
3459
3460                 abut_ex = ex - 1;
3461                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3462                 prev_len = ext4_ext_get_actual_len(abut_ex);
3463                 prev_pblk = ext4_ext_pblock(abut_ex);
3464                 ee_pblk = ext4_ext_pblock(ex);
3465
3466                 /*
3467                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3468                  * upon those conditions:
3469                  * - C1: abut_ex is initialized,
3470                  * - C2: abut_ex is logically abutting ex,
3471                  * - C3: abut_ex is physically abutting ex,
3472                  * - C4: abut_ex can receive the additional blocks without
3473                  *   overflowing the (initialized) length limit.
3474                  */
3475                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3476                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3477                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3478                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3479                         err = ext4_ext_get_access(handle, inode, path + depth);
3480                         if (err)
3481                                 goto out;
3482
3483                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3484                                 map, ex, abut_ex);
3485
3486                         /* Shift the start of ex by 'map_len' blocks */
3487                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3488                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3489                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3490                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3491
3492                         /* Extend abut_ex by 'map_len' blocks */
3493                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3494
3495                         /* Result: number of initialized blocks past m_lblk */
3496                         allocated = map_len;
3497                 }
3498         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3499                    (map_len < ee_len) &&        /*L1*/
3500                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3501                 /* See if we can merge right */
3502                 ext4_lblk_t next_lblk;
3503                 ext4_fsblk_t next_pblk, ee_pblk;
3504                 unsigned int next_len;
3505
3506                 abut_ex = ex + 1;
3507                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3508                 next_len = ext4_ext_get_actual_len(abut_ex);
3509                 next_pblk = ext4_ext_pblock(abut_ex);
3510                 ee_pblk = ext4_ext_pblock(ex);
3511
3512                 /*
3513                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3514                  * upon those conditions:
3515                  * - C1: abut_ex is initialized,
3516                  * - C2: abut_ex is logically abutting ex,
3517                  * - C3: abut_ex is physically abutting ex,
3518                  * - C4: abut_ex can receive the additional blocks without
3519                  *   overflowing the (initialized) length limit.
3520                  */
3521                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3522                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3523                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3524                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3525                         err = ext4_ext_get_access(handle, inode, path + depth);
3526                         if (err)
3527                                 goto out;
3528
3529                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3530                                 map, ex, abut_ex);
3531
3532                         /* Shift the start of abut_ex by 'map_len' blocks */
3533                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3534                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3535                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3536                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3537
3538                         /* Extend abut_ex by 'map_len' blocks */
3539                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3540
3541                         /* Result: number of initialized blocks past m_lblk */
3542                         allocated = map_len;
3543                 }
3544         }
3545         if (allocated) {
3546                 /* Mark the block containing both extents as dirty */
3547                 ext4_ext_dirty(handle, inode, path + depth);
3548
3549                 /* Update path to point to the right extent */
3550                 path[depth].p_ext = abut_ex;
3551                 goto out;
3552         } else
3553                 allocated = ee_len - (map->m_lblk - ee_block);
3554
3555         WARN_ON(map->m_lblk < ee_block);
3556         /*
3557          * It is safe to convert extent to initialized via explicit
3558          * zeroout only if extent is fully inside i_size or new_size.
3559          */
3560         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3561
3562         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3563                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3564                         (inode->i_sb->s_blocksize_bits - 10);
3565
3566         if (ext4_encrypted_inode(inode))
3567                 max_zeroout = 0;
3568
3569         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3570         if (max_zeroout && (ee_len <= max_zeroout)) {
3571                 err = ext4_ext_zeroout(inode, ex);
3572                 if (err)
3573                         goto out;
3574                 zero_ex.ee_block = ex->ee_block;
3575                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3576                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3577
3578                 err = ext4_ext_get_access(handle, inode, path + depth);
3579                 if (err)
3580                         goto out;
3581                 ext4_ext_mark_initialized(ex);
3582                 ext4_ext_try_to_merge(handle, inode, path, ex);
3583                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3584                 goto out;
3585         }
3586
3587         /*
3588          * four cases:
3589          * 1. split the extent into three extents.
3590          * 2. split the extent into two extents, zeroout the first half.
3591          * 3. split the extent into two extents, zeroout the second half.
3592          * 4. split the extent into two extents with out zeroout.
3593          */
3594         split_map.m_lblk = map->m_lblk;
3595         split_map.m_len = map->m_len;
3596
3597         if (max_zeroout && (allocated > map->m_len)) {
3598                 if (allocated <= max_zeroout) {
3599                         /* case 3 */
3600                         zero_ex.ee_block =
3601                                          cpu_to_le32(map->m_lblk);
3602                         zero_ex.ee_len = cpu_to_le16(allocated);
3603                         ext4_ext_store_pblock(&zero_ex,
3604                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3605                         err = ext4_ext_zeroout(inode, &zero_ex);
3606                         if (err)
3607                                 goto out;
3608                         split_map.m_lblk = map->m_lblk;
3609                         split_map.m_len = allocated;
3610                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3611                         /* case 2 */
3612                         if (map->m_lblk != ee_block) {
3613                                 zero_ex.ee_block = ex->ee_block;
3614                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3615                                                         ee_block);
3616                                 ext4_ext_store_pblock(&zero_ex,
3617                                                       ext4_ext_pblock(ex));
3618                                 err = ext4_ext_zeroout(inode, &zero_ex);
3619                                 if (err)
3620                                         goto out;
3621                         }
3622
3623                         split_map.m_lblk = ee_block;
3624                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3625                         allocated = map->m_len;
3626                 }
3627         }
3628
3629         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3630                                 flags);
3631         if (err > 0)
3632                 err = 0;
3633 out:
3634         /* If we have gotten a failure, don't zero out status tree */
3635         if (!err)
3636                 err = ext4_zeroout_es(inode, &zero_ex);
3637         return err ? err : allocated;
3638 }
3639
3640 /*
3641  * This function is called by ext4_ext_map_blocks() from
3642  * ext4_get_blocks_dio_write() when DIO to write
3643  * to an unwritten extent.
3644  *
3645  * Writing to an unwritten extent may result in splitting the unwritten
3646  * extent into multiple initialized/unwritten extents (up to three)
3647  * There are three possibilities:
3648  *   a> There is no split required: Entire extent should be unwritten
3649  *   b> Splits in two extents: Write is happening at either end of the extent
3650  *   c> Splits in three extents: Somone is writing in middle of the extent
3651  *
3652  * This works the same way in the case of initialized -> unwritten conversion.
3653  *
3654  * One of more index blocks maybe needed if the extent tree grow after
3655  * the unwritten extent split. To prevent ENOSPC occur at the IO
3656  * complete, we need to split the unwritten extent before DIO submit
3657  * the IO. The unwritten extent called at this time will be split
3658  * into three unwritten extent(at most). After IO complete, the part
3659  * being filled will be convert to initialized by the end_io callback function
3660  * via ext4_convert_unwritten_extents().
3661  *
3662  * Returns the size of unwritten extent to be written on success.
3663  */
3664 static int ext4_split_convert_extents(handle_t *handle,
3665                                         struct inode *inode,
3666                                         struct ext4_map_blocks *map,
3667                                         struct ext4_ext_path **ppath,
3668                                         int flags)
3669 {
3670         struct ext4_ext_path *path = *ppath;
3671         ext4_lblk_t eof_block;
3672         ext4_lblk_t ee_block;
3673         struct ext4_extent *ex;
3674         unsigned int ee_len;
3675         int split_flag = 0, depth;
3676
3677         ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3678                   __func__, inode->i_ino,
3679                   (unsigned long long)map->m_lblk, map->m_len);
3680
3681         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3682                 inode->i_sb->s_blocksize_bits;
3683         if (eof_block < map->m_lblk + map->m_len)
3684                 eof_block = map->m_lblk + map->m_len;
3685         /*
3686          * It is safe to convert extent to initialized via explicit
3687          * zeroout only if extent is fully insde i_size or new_size.
3688          */
3689         depth = ext_depth(inode);
3690         ex = path[depth].p_ext;
3691         ee_block = le32_to_cpu(ex->ee_block);
3692         ee_len = ext4_ext_get_actual_len(ex);
3693
3694         /* Convert to unwritten */
3695         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3696                 split_flag |= EXT4_EXT_DATA_VALID1;
3697         /* Convert to initialized */
3698         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3699                 split_flag |= ee_block + ee_len <= eof_block ?
3700                               EXT4_EXT_MAY_ZEROOUT : 0;
3701                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3702         }
3703         flags |= EXT4_GET_BLOCKS_PRE_IO;
3704         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3705 }
3706
3707 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3708                                                 struct inode *inode,
3709                                                 struct ext4_map_blocks *map,
3710                                                 struct ext4_ext_path **ppath)
3711 {
3712         struct ext4_ext_path *path = *ppath;
3713         struct ext4_extent *ex;
3714         ext4_lblk_t ee_block;
3715         unsigned int ee_len;
3716         int depth;
3717         int err = 0;
3718
3719         depth = ext_depth(inode);
3720         ex = path[depth].p_ext;
3721         ee_block = le32_to_cpu(ex->ee_block);
3722         ee_len = ext4_ext_get_actual_len(ex);
3723
3724         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3725                 "block %llu, max_blocks %u\n", inode->i_ino,
3726                   (unsigned long long)ee_block, ee_len);
3727
3728         /* If extent is larger than requested it is a clear sign that we still
3729          * have some extent state machine issues left. So extent_split is still
3730          * required.
3731          * TODO: Once all related issues will be fixed this situation should be
3732          * illegal.
3733          */
3734         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3735 #ifdef EXT4_DEBUG
3736                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3737                              " len %u; IO logical block %llu, len %u\n",
3738                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3739                              (unsigned long long)map->m_lblk, map->m_len);
3740 #endif
3741                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3742                                                  EXT4_GET_BLOCKS_CONVERT);
3743                 if (err < 0)
3744                         return err;
3745                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3746                 if (IS_ERR(path))
3747                         return PTR_ERR(path);
3748                 depth = ext_depth(inode);
3749                 ex = path[depth].p_ext;
3750         }
3751
3752         err = ext4_ext_get_access(handle, inode, path + depth);
3753         if (err)
3754                 goto out;
3755         /* first mark the extent as initialized */
3756         ext4_ext_mark_initialized(ex);
3757
3758         /* note: ext4_ext_correct_indexes() isn't needed here because
3759          * borders are not changed
3760          */
3761         ext4_ext_try_to_merge(handle, inode, path, ex);
3762
3763         /* Mark modified extent as dirty */
3764         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3765 out:
3766         ext4_ext_show_leaf(inode, path);
3767         return err;
3768 }
3769
3770 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3771                         sector_t block, int count)
3772 {
3773         int i;
3774         for (i = 0; i < count; i++)
3775                 unmap_underlying_metadata(bdev, block + i);
3776 }
3777
3778 /*
3779  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3780  */
3781 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3782                               ext4_lblk_t lblk,
3783                               struct ext4_ext_path *path,
3784                               unsigned int len)
3785 {
3786         int i, depth;
3787         struct ext4_extent_header *eh;
3788         struct ext4_extent *last_ex;
3789
3790         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3791                 return 0;
3792
3793         depth = ext_depth(inode);
3794         eh = path[depth].p_hdr;
3795
3796         /*
3797          * We're going to remove EOFBLOCKS_FL entirely in future so we
3798          * do not care for this case anymore. Simply remove the flag
3799          * if there are no extents.
3800          */
3801         if (unlikely(!eh->eh_entries))
3802                 goto out;
3803         last_ex = EXT_LAST_EXTENT(eh);
3804         /*
3805          * We should clear the EOFBLOCKS_FL flag if we are writing the
3806          * last block in the last extent in the file.  We test this by
3807          * first checking to see if the caller to
3808          * ext4_ext_get_blocks() was interested in the last block (or
3809          * a block beyond the last block) in the current extent.  If
3810          * this turns out to be false, we can bail out from this
3811          * function immediately.
3812          */
3813         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3814             ext4_ext_get_actual_len(last_ex))
3815                 return 0;
3816         /*
3817          * If the caller does appear to be planning to write at or
3818          * beyond the end of the current extent, we then test to see
3819          * if the current extent is the last extent in the file, by
3820          * checking to make sure it was reached via the rightmost node
3821          * at each level of the tree.
3822          */
3823         for (i = depth-1; i >= 0; i--)
3824                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3825                         return 0;
3826 out:
3827         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3828         return ext4_mark_inode_dirty(handle, inode);
3829 }
3830
3831 /**
3832  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3833  *
3834  * Return 1 if there is a delalloc block in the range, otherwise 0.
3835  */
3836 int ext4_find_delalloc_range(struct inode *inode,
3837                              ext4_lblk_t lblk_start,
3838                              ext4_lblk_t lblk_end)
3839 {
3840         struct extent_status es;
3841
3842         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3843         if (es.es_len == 0)
3844                 return 0; /* there is no delay extent in this tree */
3845         else if (es.es_lblk <= lblk_start &&
3846                  lblk_start < es.es_lblk + es.es_len)
3847                 return 1;
3848         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3849                 return 1;
3850         else
3851                 return 0;
3852 }
3853
3854 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3855 {
3856         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3857         ext4_lblk_t lblk_start, lblk_end;
3858         lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3859         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3860
3861         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3862 }
3863
3864 /**
3865  * Determines how many complete clusters (out of those specified by the 'map')
3866  * are under delalloc and were reserved quota for.
3867  * This function is called when we are writing out the blocks that were
3868  * originally written with their allocation delayed, but then the space was
3869  * allocated using fallocate() before the delayed allocation could be resolved.
3870  * The cases to look for are:
3871  * ('=' indicated delayed allocated blocks
3872  *  '-' indicates non-delayed allocated blocks)
3873  * (a) partial clusters towards beginning and/or end outside of allocated range
3874  *     are not delalloc'ed.
3875  *      Ex:
3876  *      |----c---=|====c====|====c====|===-c----|
3877  *               |++++++ allocated ++++++|
3878  *      ==> 4 complete clusters in above example
3879  *
3880  * (b) partial cluster (outside of allocated range) towards either end is
3881  *     marked for delayed allocation. In this case, we will exclude that
3882  *     cluster.
3883  *      Ex:
3884  *      |----====c========|========c========|
3885  *           |++++++ allocated ++++++|
3886  *      ==> 1 complete clusters in above example
3887  *
3888  *      Ex:
3889  *      |================c================|
3890  *            |++++++ allocated ++++++|
3891  *      ==> 0 complete clusters in above example
3892  *
3893  * The ext4_da_update_reserve_space will be called only if we
3894  * determine here that there were some "entire" clusters that span
3895  * this 'allocated' range.
3896  * In the non-bigalloc case, this function will just end up returning num_blks
3897  * without ever calling ext4_find_delalloc_range.
3898  */
3899 static unsigned int
3900 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3901                            unsigned int num_blks)
3902 {
3903         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3904         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3905         ext4_lblk_t lblk_from, lblk_to, c_offset;
3906         unsigned int allocated_clusters = 0;
3907
3908         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3909         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3910
3911         /* max possible clusters for this allocation */
3912         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3913
3914         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3915
3916         /* Check towards left side */
3917         c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3918         if (c_offset) {
3919                 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3920                 lblk_to = lblk_from + c_offset - 1;
3921
3922                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3923                         allocated_clusters--;
3924         }
3925
3926         /* Now check towards right. */
3927         c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3928         if (allocated_clusters && c_offset) {
3929                 lblk_from = lblk_start + num_blks;
3930                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3931
3932                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3933                         allocated_clusters--;
3934         }
3935
3936         return allocated_clusters;
3937 }
3938
3939 static int
3940 convert_initialized_extent(handle_t *handle, struct inode *inode,
3941                            struct ext4_map_blocks *map,
3942                            struct ext4_ext_path **ppath, int flags,
3943                            unsigned int allocated, ext4_fsblk_t newblock)
3944 {
3945         struct ext4_ext_path *path = *ppath;
3946         struct ext4_extent *ex;
3947         ext4_lblk_t ee_block;
3948         unsigned int ee_len;
3949         int depth;
3950         int err = 0;
3951
3952         /*
3953          * Make sure that the extent is no bigger than we support with
3954          * unwritten extent
3955          */
3956         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3957                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3958
3959         depth = ext_depth(inode);
3960         ex = path[depth].p_ext;
3961         ee_block = le32_to_cpu(ex->ee_block);
3962         ee_len = ext4_ext_get_actual_len(ex);
3963
3964         ext_debug("%s: inode %lu, logical"
3965                 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3966                   (unsigned long long)ee_block, ee_len);
3967
3968         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3969                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3970                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3971                 if (err < 0)
3972                         return err;
3973                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3974                 if (IS_ERR(path))
3975                         return PTR_ERR(path);
3976                 depth = ext_depth(inode);
3977                 ex = path[depth].p_ext;
3978                 if (!ex) {
3979                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3980                                          (unsigned long) map->m_lblk);
3981                         return -EFSCORRUPTED;
3982                 }
3983         }
3984
3985         err = ext4_ext_get_access(handle, inode, path + depth);
3986         if (err)
3987                 return err;
3988         /* first mark the extent as unwritten */
3989         ext4_ext_mark_unwritten(ex);
3990
3991         /* note: ext4_ext_correct_indexes() isn't needed here because
3992          * borders are not changed
3993          */
3994         ext4_ext_try_to_merge(handle, inode, path, ex);
3995
3996         /* Mark modified extent as dirty */
3997         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3998         if (err)
3999                 return err;
4000         ext4_ext_show_leaf(inode, path);
4001
4002         ext4_update_inode_fsync_trans(handle, inode, 1);
4003         err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
4004         if (err)
4005                 return err;
4006         map->m_flags |= EXT4_MAP_UNWRITTEN;
4007         if (allocated > map->m_len)
4008                 allocated = map->m_len;
4009         map->m_len = allocated;
4010         return allocated;
4011 }
4012
4013 static int
4014 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4015                         struct ext4_map_blocks *map,
4016                         struct ext4_ext_path **ppath, int flags,
4017                         unsigned int allocated, ext4_fsblk_t newblock)
4018 {
4019         struct ext4_ext_path *path = *ppath;
4020         int ret = 0;
4021         int err = 0;
4022         ext4_io_end_t *io = ext4_inode_aio(inode);
4023
4024         ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4025                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
4026                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4027                   flags, allocated);
4028         ext4_ext_show_leaf(inode, path);
4029
4030         /*
4031          * When writing into unwritten space, we should not fail to
4032          * allocate metadata blocks for the new extent block if needed.
4033          */
4034         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4035
4036         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4037                                                     allocated, newblock);
4038
4039         /* get_block() before submit the IO, split the extent */
4040         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4041                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4042                                          flags | EXT4_GET_BLOCKS_CONVERT);
4043                 if (ret <= 0)
4044                         goto out;
4045                 /*
4046                  * Flag the inode(non aio case) or end_io struct (aio case)
4047                  * that this IO needs to conversion to written when IO is
4048                  * completed
4049                  */
4050                 if (io)
4051                         ext4_set_io_unwritten_flag(inode, io);
4052                 else
4053                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
4054                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4055                 goto out;
4056         }
4057         /* IO end_io complete, convert the filled extent to written */
4058         if (flags & EXT4_GET_BLOCKS_CONVERT) {
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                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4117                                         newblock + map->m_len,
4118                                         allocated - map->m_len);
4119                 allocated = map->m_len;
4120         }
4121         map->m_len = allocated;
4122
4123         /*
4124          * If we have done fallocate with the offset that is already
4125          * delayed allocated, we would have block reservation
4126          * and quota reservation done in the delayed write path.
4127          * But fallocate would have already updated quota and block
4128          * count for this offset. So cancel these reservation
4129          */
4130         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4131                 unsigned int reserved_clusters;
4132                 reserved_clusters = get_reserved_cluster_alloc(inode,
4133                                 map->m_lblk, map->m_len);
4134                 if (reserved_clusters)
4135                         ext4_da_update_reserve_space(inode,
4136                                                      reserved_clusters,
4137                                                      0);
4138         }
4139
4140 map_out:
4141         map->m_flags |= EXT4_MAP_MAPPED;
4142         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4143                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4144                                          map->m_len);
4145                 if (err < 0)
4146                         goto out2;
4147         }
4148 out1:
4149         if (allocated > map->m_len)
4150                 allocated = map->m_len;
4151         ext4_ext_show_leaf(inode, path);
4152         map->m_pblk = newblock;
4153         map->m_len = allocated;
4154 out2:
4155         return err ? err : allocated;
4156 }
4157
4158 /*
4159  * get_implied_cluster_alloc - check to see if the requested
4160  * allocation (in the map structure) overlaps with a cluster already
4161  * allocated in an extent.
4162  *      @sb     The filesystem superblock structure
4163  *      @map    The requested lblk->pblk mapping
4164  *      @ex     The extent structure which might contain an implied
4165  *                      cluster allocation
4166  *
4167  * This function is called by ext4_ext_map_blocks() after we failed to
4168  * find blocks that were already in the inode's extent tree.  Hence,
4169  * we know that the beginning of the requested region cannot overlap
4170  * the extent from the inode's extent tree.  There are three cases we
4171  * want to catch.  The first is this case:
4172  *
4173  *               |--- cluster # N--|
4174  *    |--- extent ---|  |---- requested region ---|
4175  *                      |==========|
4176  *
4177  * The second case that we need to test for is this one:
4178  *
4179  *   |--------- cluster # N ----------------|
4180  *         |--- requested region --|   |------- extent ----|
4181  *         |=======================|
4182  *
4183  * The third case is when the requested region lies between two extents
4184  * within the same cluster:
4185  *          |------------- cluster # N-------------|
4186  * |----- ex -----|                  |---- ex_right ----|
4187  *                  |------ requested region ------|
4188  *                  |================|
4189  *
4190  * In each of the above cases, we need to set the map->m_pblk and
4191  * map->m_len so it corresponds to the return the extent labelled as
4192  * "|====|" from cluster #N, since it is already in use for data in
4193  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4194  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4195  * as a new "allocated" block region.  Otherwise, we will return 0 and
4196  * ext4_ext_map_blocks() will then allocate one or more new clusters
4197  * by calling ext4_mb_new_blocks().
4198  */
4199 static int get_implied_cluster_alloc(struct super_block *sb,
4200                                      struct ext4_map_blocks *map,
4201                                      struct ext4_extent *ex,
4202                                      struct ext4_ext_path *path)
4203 {
4204         struct ext4_sb_info *sbi = EXT4_SB(sb);
4205         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4206         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4207         ext4_lblk_t rr_cluster_start;
4208         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4209         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4210         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4211
4212         /* The extent passed in that we are trying to match */
4213         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4214         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4215
4216         /* The requested region passed into ext4_map_blocks() */
4217         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4218
4219         if ((rr_cluster_start == ex_cluster_end) ||
4220             (rr_cluster_start == ex_cluster_start)) {
4221                 if (rr_cluster_start == ex_cluster_end)
4222                         ee_start += ee_len - 1;
4223                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4224                 map->m_len = min(map->m_len,
4225                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4226                 /*
4227                  * Check for and handle this case:
4228                  *
4229                  *   |--------- cluster # N-------------|
4230                  *                     |------- extent ----|
4231                  *         |--- requested region ---|
4232                  *         |===========|
4233                  */
4234
4235                 if (map->m_lblk < ee_block)
4236                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4237
4238                 /*
4239                  * Check for the case where there is already another allocated
4240                  * block to the right of 'ex' but before the end of the cluster.
4241                  *
4242                  *          |------------- cluster # N-------------|
4243                  * |----- ex -----|                  |---- ex_right ----|
4244                  *                  |------ requested region ------|
4245                  *                  |================|
4246                  */
4247                 if (map->m_lblk > ee_block) {
4248                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4249                         map->m_len = min(map->m_len, next - map->m_lblk);
4250                 }
4251
4252                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4253                 return 1;
4254         }
4255
4256         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4257         return 0;
4258 }
4259
4260
4261 /*
4262  * Block allocation/map/preallocation routine for extents based files
4263  *
4264  *
4265  * Need to be called with
4266  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4267  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4268  *
4269  * return > 0, number of of blocks already mapped/allocated
4270  *          if create == 0 and these are pre-allocated blocks
4271  *              buffer head is unmapped
4272  *          otherwise blocks are mapped
4273  *
4274  * return = 0, if plain look up failed (blocks have not been allocated)
4275  *          buffer head is unmapped
4276  *
4277  * return < 0, error case.
4278  */
4279 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4280                         struct ext4_map_blocks *map, int flags)
4281 {
4282         struct ext4_ext_path *path = NULL;
4283         struct ext4_extent newex, *ex, *ex2;
4284         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4285         ext4_fsblk_t newblock = 0;
4286         int free_on_err = 0, err = 0, depth, ret;
4287         unsigned int allocated = 0, offset = 0;
4288         unsigned int allocated_clusters = 0;
4289         struct ext4_allocation_request ar;
4290         ext4_io_end_t *io = ext4_inode_aio(inode);
4291         ext4_lblk_t cluster_offset;
4292         int set_unwritten = 0;
4293         bool map_from_cluster = false;
4294
4295         ext_debug("blocks %u/%u requested for inode %lu\n",
4296                   map->m_lblk, map->m_len, inode->i_ino);
4297         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4298
4299         /* find extent for this block */
4300         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4301         if (IS_ERR(path)) {
4302                 err = PTR_ERR(path);
4303                 path = NULL;
4304                 goto out2;
4305         }
4306
4307         depth = ext_depth(inode);
4308
4309         /*
4310          * consistent leaf must not be empty;
4311          * this situation is possible, though, _during_ tree modification;
4312          * this is why assert can't be put in ext4_find_extent()
4313          */
4314         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4315                 EXT4_ERROR_INODE(inode, "bad extent address "
4316                                  "lblock: %lu, depth: %d pblock %lld",
4317                                  (unsigned long) map->m_lblk, depth,
4318                                  path[depth].p_block);
4319                 err = -EFSCORRUPTED;
4320                 goto out2;
4321         }
4322
4323         ex = path[depth].p_ext;
4324         if (ex) {
4325                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4326                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4327                 unsigned short ee_len;
4328
4329
4330                 /*
4331                  * unwritten extents are treated as holes, except that
4332                  * we split out initialized portions during a write.
4333                  */
4334                 ee_len = ext4_ext_get_actual_len(ex);
4335
4336                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4337
4338                 /* if found extent covers block, simply return it */
4339                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4340                         newblock = map->m_lblk - ee_block + ee_start;
4341                         /* number of remaining blocks in the extent */
4342                         allocated = ee_len - (map->m_lblk - ee_block);
4343                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4344                                   ee_block, ee_len, newblock);
4345
4346                         /*
4347                          * If the extent is initialized check whether the
4348                          * caller wants to convert it to unwritten.
4349                          */
4350                         if ((!ext4_ext_is_unwritten(ex)) &&
4351                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4352                                 allocated = convert_initialized_extent(
4353                                                 handle, inode, map, &path,
4354                                                 flags, allocated, newblock);
4355                                 goto out2;
4356                         } else if (!ext4_ext_is_unwritten(ex))
4357                                 goto out;
4358
4359                         ret = ext4_ext_handle_unwritten_extents(
4360                                 handle, inode, map, &path, flags,
4361                                 allocated, newblock);
4362                         if (ret < 0)
4363                                 err = ret;
4364                         else
4365                                 allocated = ret;
4366                         goto out2;
4367                 }
4368         }
4369
4370         /*
4371          * requested block isn't allocated yet;
4372          * we couldn't try to create block if create flag is zero
4373          */
4374         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4375                 /*
4376                  * put just found gap into cache to speed up
4377                  * subsequent requests
4378                  */
4379                 ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
4380                 goto out2;
4381         }
4382
4383         /*
4384          * Okay, we need to do block allocation.
4385          */
4386         newex.ee_block = cpu_to_le32(map->m_lblk);
4387         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4388
4389         /*
4390          * If we are doing bigalloc, check to see if the extent returned
4391          * by ext4_find_extent() implies a cluster we can use.
4392          */
4393         if (cluster_offset && ex &&
4394             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4395                 ar.len = allocated = map->m_len;
4396                 newblock = map->m_pblk;
4397                 map_from_cluster = true;
4398                 goto got_allocated_blocks;
4399         }
4400
4401         /* find neighbour allocated blocks */
4402         ar.lleft = map->m_lblk;
4403         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4404         if (err)
4405                 goto out2;
4406         ar.lright = map->m_lblk;
4407         ex2 = NULL;
4408         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4409         if (err)
4410                 goto out2;
4411
4412         /* Check if the extent after searching to the right implies a
4413          * cluster we can use. */
4414         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4415             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4416                 ar.len = allocated = map->m_len;
4417                 newblock = map->m_pblk;
4418                 map_from_cluster = true;
4419                 goto got_allocated_blocks;
4420         }
4421
4422         /*
4423          * See if request is beyond maximum number of blocks we can have in
4424          * a single extent. For an initialized extent this limit is
4425          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4426          * EXT_UNWRITTEN_MAX_LEN.
4427          */
4428         if (map->m_len > EXT_INIT_MAX_LEN &&
4429             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4430                 map->m_len = EXT_INIT_MAX_LEN;
4431         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4432                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4433                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4434
4435         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4436         newex.ee_len = cpu_to_le16(map->m_len);
4437         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4438         if (err)
4439                 allocated = ext4_ext_get_actual_len(&newex);
4440         else
4441                 allocated = map->m_len;
4442
4443         /* allocate new block */
4444         ar.inode = inode;
4445         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4446         ar.logical = map->m_lblk;
4447         /*
4448          * We calculate the offset from the beginning of the cluster
4449          * for the logical block number, since when we allocate a
4450          * physical cluster, the physical block should start at the
4451          * same offset from the beginning of the cluster.  This is
4452          * needed so that future calls to get_implied_cluster_alloc()
4453          * work correctly.
4454          */
4455         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4456         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4457         ar.goal -= offset;
4458         ar.logical -= offset;
4459         if (S_ISREG(inode->i_mode))
4460                 ar.flags = EXT4_MB_HINT_DATA;
4461         else
4462                 /* disable in-core preallocation for non-regular files */
4463                 ar.flags = 0;
4464         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4465                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4466         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4467                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4468         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4469                 ar.flags |= EXT4_MB_USE_RESERVED;
4470         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4471         if (!newblock)
4472                 goto out2;
4473         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4474                   ar.goal, newblock, allocated);
4475         free_on_err = 1;
4476         allocated_clusters = ar.len;
4477         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4478         if (ar.len > allocated)
4479                 ar.len = allocated;
4480
4481 got_allocated_blocks:
4482         /* try to insert new extent into found leaf and return */
4483         ext4_ext_store_pblock(&newex, newblock + offset);
4484         newex.ee_len = cpu_to_le16(ar.len);
4485         /* Mark unwritten */
4486         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4487                 ext4_ext_mark_unwritten(&newex);
4488                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4489                 /*
4490                  * io_end structure was created for every IO write to an
4491                  * unwritten extent. To avoid unnecessary conversion,
4492                  * here we flag the IO that really needs the conversion.
4493                  * For non asycn direct IO case, flag the inode state
4494                  * that we need to perform conversion when IO is done.
4495                  */
4496                 if (flags & EXT4_GET_BLOCKS_PRE_IO)
4497                         set_unwritten = 1;
4498         }
4499
4500         err = 0;
4501         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4502                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4503                                          path, ar.len);
4504         if (!err)
4505                 err = ext4_ext_insert_extent(handle, inode, &path,
4506                                              &newex, flags);
4507
4508         if (!err && set_unwritten) {
4509                 if (io)
4510                         ext4_set_io_unwritten_flag(inode, io);
4511                 else
4512                         ext4_set_inode_state(inode,
4513                                              EXT4_STATE_DIO_UNWRITTEN);
4514         }
4515
4516         if (err && free_on_err) {
4517                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4518                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4519                 /* free data blocks we just allocated */
4520                 /* not a good idea to call discard here directly,
4521                  * but otherwise we'd need to call it every free() */
4522                 ext4_discard_preallocations(inode);
4523                 ext4_free_blocks(handle, inode, NULL, newblock,
4524                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4525                 goto out2;
4526         }
4527
4528         /* previous routine could use block we allocated */
4529         newblock = ext4_ext_pblock(&newex);
4530         allocated = ext4_ext_get_actual_len(&newex);
4531         if (allocated > map->m_len)
4532                 allocated = map->m_len;
4533         map->m_flags |= EXT4_MAP_NEW;
4534
4535         /*
4536          * Update reserved blocks/metadata blocks after successful
4537          * block allocation which had been deferred till now.
4538          */
4539         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4540                 unsigned int reserved_clusters;
4541                 /*
4542                  * Check how many clusters we had reserved this allocated range
4543                  */
4544                 reserved_clusters = get_reserved_cluster_alloc(inode,
4545                                                 map->m_lblk, allocated);
4546                 if (!map_from_cluster) {
4547                         BUG_ON(allocated_clusters < reserved_clusters);
4548                         if (reserved_clusters < allocated_clusters) {
4549                                 struct ext4_inode_info *ei = EXT4_I(inode);
4550                                 int reservation = allocated_clusters -
4551                                                   reserved_clusters;
4552                                 /*
4553                                  * It seems we claimed few clusters outside of
4554                                  * the range of this allocation. We should give
4555                                  * it back to the reservation pool. This can
4556                                  * happen in the following case:
4557                                  *
4558                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4559                                  *   cluster has 4 blocks. Thus, the clusters
4560                                  *   are [0-3],[4-7],[8-11]...
4561                                  * * First comes delayed allocation write for
4562                                  *   logical blocks 10 & 11. Since there were no
4563                                  *   previous delayed allocated blocks in the
4564                                  *   range [8-11], we would reserve 1 cluster
4565                                  *   for this write.
4566                                  * * Next comes write for logical blocks 3 to 8.
4567                                  *   In this case, we will reserve 2 clusters
4568                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4569                                  *   that range has a delayed allocated blocks.
4570                                  *   Thus total reserved clusters now becomes 3.
4571                                  * * Now, during the delayed allocation writeout
4572                                  *   time, we will first write blocks [3-8] and
4573                                  *   allocate 3 clusters for writing these
4574                                  *   blocks. Also, we would claim all these
4575                                  *   three clusters above.
4576                                  * * Now when we come here to writeout the
4577                                  *   blocks [10-11], we would expect to claim
4578                                  *   the reservation of 1 cluster we had made
4579                                  *   (and we would claim it since there are no
4580                                  *   more delayed allocated blocks in the range
4581                                  *   [8-11]. But our reserved cluster count had
4582                                  *   already gone to 0.
4583                                  *
4584                                  *   Thus, at the step 4 above when we determine
4585                                  *   that there are still some unwritten delayed
4586                                  *   allocated blocks outside of our current
4587                                  *   block range, we should increment the
4588                                  *   reserved clusters count so that when the
4589                                  *   remaining blocks finally gets written, we
4590                                  *   could claim them.
4591                                  */
4592                                 dquot_reserve_block(inode,
4593                                                 EXT4_C2B(sbi, reservation));
4594                                 spin_lock(&ei->i_block_reservation_lock);
4595                                 ei->i_reserved_data_blocks += reservation;
4596                                 spin_unlock(&ei->i_block_reservation_lock);
4597                         }
4598                         /*
4599                          * We will claim quota for all newly allocated blocks.
4600                          * We're updating the reserved space *after* the
4601                          * correction above so we do not accidentally free
4602                          * all the metadata reservation because we might
4603                          * actually need it later on.
4604                          */
4605                         ext4_da_update_reserve_space(inode, allocated_clusters,
4606                                                         1);
4607                 }
4608         }
4609
4610         /*
4611          * Cache the extent and update transaction to commit on fdatasync only
4612          * when it is _not_ an unwritten extent.
4613          */
4614         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4615                 ext4_update_inode_fsync_trans(handle, inode, 1);
4616         else
4617                 ext4_update_inode_fsync_trans(handle, inode, 0);
4618 out:
4619         if (allocated > map->m_len)
4620                 allocated = map->m_len;
4621         ext4_ext_show_leaf(inode, path);
4622         map->m_flags |= EXT4_MAP_MAPPED;
4623         map->m_pblk = newblock;
4624         map->m_len = allocated;
4625 out2:
4626         ext4_ext_drop_refs(path);
4627         kfree(path);
4628
4629         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4630                                        err ? err : allocated);
4631         return err ? err : allocated;
4632 }
4633
4634 void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4635 {
4636         struct super_block *sb = inode->i_sb;
4637         ext4_lblk_t last_block;
4638         int err = 0;
4639
4640         /*
4641          * TODO: optimization is possible here.
4642          * Probably we need not scan at all,
4643          * because page truncation is enough.
4644          */
4645
4646         /* we have to know where to truncate from in crash case */
4647         EXT4_I(inode)->i_disksize = inode->i_size;
4648         ext4_mark_inode_dirty(handle, inode);
4649
4650         last_block = (inode->i_size + sb->s_blocksize - 1)
4651                         >> EXT4_BLOCK_SIZE_BITS(sb);
4652 retry:
4653         err = ext4_es_remove_extent(inode, last_block,
4654                                     EXT_MAX_BLOCKS - last_block);
4655         if (err == -ENOMEM) {
4656                 cond_resched();
4657                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4658                 goto retry;
4659         }
4660         if (err) {
4661                 ext4_std_error(inode->i_sb, err);
4662                 return;
4663         }
4664         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4665         ext4_std_error(inode->i_sb, err);
4666 }
4667
4668 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4669                                   ext4_lblk_t len, loff_t new_size,
4670                                   int flags, int mode)
4671 {
4672         struct inode *inode = file_inode(file);
4673         handle_t *handle;
4674         int ret = 0;
4675         int ret2 = 0;
4676         int retries = 0;
4677         int depth = 0;
4678         struct ext4_map_blocks map;
4679         unsigned int credits;
4680         loff_t epos;
4681
4682         map.m_lblk = offset;
4683         map.m_len = len;
4684         /*
4685          * Don't normalize the request if it can fit in one extent so
4686          * that it doesn't get unnecessarily split into multiple
4687          * extents.
4688          */
4689         if (len <= EXT_UNWRITTEN_MAX_LEN)
4690                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4691
4692         /*
4693          * credits to insert 1 extent into extent tree
4694          */
4695         credits = ext4_chunk_trans_blocks(inode, len);
4696         /*
4697          * We can only call ext_depth() on extent based inodes
4698          */
4699         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4700                 depth = ext_depth(inode);
4701         else
4702                 depth = -1;
4703
4704 retry:
4705         while (ret >= 0 && len) {
4706                 /*
4707                  * Recalculate credits when extent tree depth changes.
4708                  */
4709                 if (depth >= 0 && depth != ext_depth(inode)) {
4710                         credits = ext4_chunk_trans_blocks(inode, len);
4711                         depth = ext_depth(inode);
4712                 }
4713
4714                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4715                                             credits);
4716                 if (IS_ERR(handle)) {
4717                         ret = PTR_ERR(handle);
4718                         break;
4719                 }
4720                 ret = ext4_map_blocks(handle, inode, &map, flags);
4721                 if (ret <= 0) {
4722                         ext4_debug("inode #%lu: block %u: len %u: "
4723                                    "ext4_ext_map_blocks returned %d",
4724                                    inode->i_ino, map.m_lblk,
4725                                    map.m_len, ret);
4726                         ext4_mark_inode_dirty(handle, inode);
4727                         ret2 = ext4_journal_stop(handle);
4728                         break;
4729                 }
4730                 map.m_lblk += ret;
4731                 map.m_len = len = len - ret;
4732                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4733                 inode->i_ctime = ext4_current_time(inode);
4734                 if (new_size) {
4735                         if (epos > new_size)
4736                                 epos = new_size;
4737                         if (ext4_update_inode_size(inode, epos) & 0x1)
4738                                 inode->i_mtime = inode->i_ctime;
4739                 } else {
4740                         if (epos > inode->i_size)
4741                                 ext4_set_inode_flag(inode,
4742                                                     EXT4_INODE_EOFBLOCKS);
4743                 }
4744                 ext4_mark_inode_dirty(handle, inode);
4745                 ret2 = ext4_journal_stop(handle);
4746                 if (ret2)
4747                         break;
4748         }
4749         if (ret == -ENOSPC &&
4750                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4751                 ret = 0;
4752                 goto retry;
4753         }
4754
4755         return ret > 0 ? ret2 : ret;
4756 }
4757
4758 static long ext4_zero_range(struct file *file, loff_t offset,
4759                             loff_t len, int mode)
4760 {
4761         struct inode *inode = file_inode(file);
4762         handle_t *handle = NULL;
4763         unsigned int max_blocks;
4764         loff_t new_size = 0;
4765         int ret = 0;
4766         int flags;
4767         int credits;
4768         int partial_begin, partial_end;
4769         loff_t start, end;
4770         ext4_lblk_t lblk;
4771         unsigned int blkbits = inode->i_blkbits;
4772
4773         trace_ext4_zero_range(inode, offset, len, mode);
4774
4775         if (!S_ISREG(inode->i_mode))
4776                 return -EINVAL;
4777
4778         /* Call ext4_force_commit to flush all data in case of data=journal. */
4779         if (ext4_should_journal_data(inode)) {
4780                 ret = ext4_force_commit(inode->i_sb);
4781                 if (ret)
4782                         return ret;
4783         }
4784
4785         /*
4786          * Round up offset. This is not fallocate, we neet to zero out
4787          * blocks, so convert interior block aligned part of the range to
4788          * unwritten and possibly manually zero out unaligned parts of the
4789          * range.
4790          */
4791         start = round_up(offset, 1 << blkbits);
4792         end = round_down((offset + len), 1 << blkbits);
4793
4794         if (start < offset || end > offset + len)
4795                 return -EINVAL;
4796         partial_begin = offset & ((1 << blkbits) - 1);
4797         partial_end = (offset + len) & ((1 << blkbits) - 1);
4798
4799         lblk = start >> blkbits;
4800         max_blocks = (end >> blkbits);
4801         if (max_blocks < lblk)
4802                 max_blocks = 0;
4803         else
4804                 max_blocks -= lblk;
4805
4806         mutex_lock(&inode->i_mutex);
4807
4808         /*
4809          * Indirect files do not support unwritten extnets
4810          */
4811         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4812                 ret = -EOPNOTSUPP;
4813                 goto out_mutex;
4814         }
4815
4816         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4817              offset + len > i_size_read(inode)) {
4818                 new_size = offset + len;
4819                 ret = inode_newsize_ok(inode, new_size);
4820                 if (ret)
4821                         goto out_mutex;
4822         }
4823
4824         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4825         if (mode & FALLOC_FL_KEEP_SIZE)
4826                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4827
4828         /* Wait all existing dio workers, newcomers will block on i_mutex */
4829         ext4_inode_block_unlocked_dio(inode);
4830         inode_dio_wait(inode);
4831
4832         /* Preallocate the range including the unaligned edges */
4833         if (partial_begin || partial_end) {
4834                 ret = ext4_alloc_file_blocks(file,
4835                                 round_down(offset, 1 << blkbits) >> blkbits,
4836                                 (round_up((offset + len), 1 << blkbits) -
4837                                  round_down(offset, 1 << blkbits)) >> blkbits,
4838                                 new_size, flags, mode);
4839                 if (ret)
4840                         goto out_dio;
4841
4842         }
4843
4844         /* Zero range excluding the unaligned edges */
4845         if (max_blocks > 0) {
4846                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4847                           EXT4_EX_NOCACHE);
4848
4849                 /*
4850                  * Prevent page faults from reinstantiating pages we have
4851                  * released from page cache.
4852                  */
4853                 down_write(&EXT4_I(inode)->i_mmap_sem);
4854                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4855                 if (ret) {
4856                         up_write(&EXT4_I(inode)->i_mmap_sem);
4857                         goto out_dio;
4858                 }
4859                 /* Now release the pages and zero block aligned part of pages */
4860                 truncate_pagecache_range(inode, start, end - 1);
4861                 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4862
4863                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4864                                              flags, mode);
4865                 up_write(&EXT4_I(inode)->i_mmap_sem);
4866                 if (ret)
4867                         goto out_dio;
4868         }
4869         if (!partial_begin && !partial_end)
4870                 goto out_dio;
4871
4872         /*
4873          * In worst case we have to writeout two nonadjacent unwritten
4874          * blocks and update the inode
4875          */
4876         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4877         if (ext4_should_journal_data(inode))
4878                 credits += 2;
4879         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4880         if (IS_ERR(handle)) {
4881                 ret = PTR_ERR(handle);
4882                 ext4_std_error(inode->i_sb, ret);
4883                 goto out_dio;
4884         }
4885
4886         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4887         if (new_size) {
4888                 ext4_update_inode_size(inode, new_size);
4889         } else {
4890                 /*
4891                 * Mark that we allocate beyond EOF so the subsequent truncate
4892                 * can proceed even if the new size is the same as i_size.
4893                 */
4894                 if ((offset + len) > i_size_read(inode))
4895                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4896         }
4897         ext4_mark_inode_dirty(handle, inode);
4898
4899         /* Zero out partial block at the edges of the range */
4900         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4901
4902         if (file->f_flags & O_SYNC)
4903                 ext4_handle_sync(handle);
4904
4905         ext4_journal_stop(handle);
4906 out_dio:
4907         ext4_inode_resume_unlocked_dio(inode);
4908 out_mutex:
4909         mutex_unlock(&inode->i_mutex);
4910         return ret;
4911 }
4912
4913 /*
4914  * preallocate space for a file. This implements ext4's fallocate file
4915  * operation, which gets called from sys_fallocate system call.
4916  * For block-mapped files, posix_fallocate should fall back to the method
4917  * of writing zeroes to the required new blocks (the same behavior which is
4918  * expected for file systems which do not support fallocate() system call).
4919  */
4920 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4921 {
4922         struct inode *inode = file_inode(file);
4923         loff_t new_size = 0;
4924         unsigned int max_blocks;
4925         int ret = 0;
4926         int flags;
4927         ext4_lblk_t lblk;
4928         unsigned int blkbits = inode->i_blkbits;
4929
4930         /*
4931          * Encrypted inodes can't handle collapse range or insert
4932          * range since we would need to re-encrypt blocks with a
4933          * different IV or XTS tweak (which are based on the logical
4934          * block number).
4935          *
4936          * XXX It's not clear why zero range isn't working, but we'll
4937          * leave it disabled for encrypted inodes for now.  This is a
4938          * bug we should fix....
4939          */
4940         if (ext4_encrypted_inode(inode) &&
4941             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4942                      FALLOC_FL_ZERO_RANGE)))
4943                 return -EOPNOTSUPP;
4944
4945         /* Return error if mode is not supported */
4946         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4947                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4948                      FALLOC_FL_INSERT_RANGE))
4949                 return -EOPNOTSUPP;
4950
4951         if (mode & FALLOC_FL_PUNCH_HOLE)
4952                 return ext4_punch_hole(inode, offset, len);
4953
4954         ret = ext4_convert_inline_data(inode);
4955         if (ret)
4956                 return ret;
4957
4958         if (mode & FALLOC_FL_COLLAPSE_RANGE)
4959                 return ext4_collapse_range(inode, offset, len);
4960
4961         if (mode & FALLOC_FL_INSERT_RANGE)
4962                 return ext4_insert_range(inode, offset, len);
4963
4964         if (mode & FALLOC_FL_ZERO_RANGE)
4965                 return ext4_zero_range(file, offset, len, mode);
4966
4967         trace_ext4_fallocate_enter(inode, offset, len, mode);
4968         lblk = offset >> blkbits;
4969         /*
4970          * We can't just convert len to max_blocks because
4971          * If blocksize = 4096 offset = 3072 and len = 2048
4972          */
4973         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4974                 - lblk;
4975
4976         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4977         if (mode & FALLOC_FL_KEEP_SIZE)
4978                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4979
4980         mutex_lock(&inode->i_mutex);
4981
4982         /*
4983          * We only support preallocation for extent-based files only
4984          */
4985         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4986                 ret = -EOPNOTSUPP;
4987                 goto out;
4988         }
4989
4990         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4991              offset + len > i_size_read(inode)) {
4992                 new_size = offset + len;
4993                 ret = inode_newsize_ok(inode, new_size);
4994                 if (ret)
4995                         goto out;
4996         }
4997
4998         /* Wait all existing dio workers, newcomers will block on i_mutex */
4999         ext4_inode_block_unlocked_dio(inode);
5000         inode_dio_wait(inode);
5001
5002         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
5003                                      flags, mode);
5004         ext4_inode_resume_unlocked_dio(inode);
5005         if (ret)
5006                 goto out;
5007
5008         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
5009                 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
5010                                                 EXT4_I(inode)->i_sync_tid);
5011         }
5012 out:
5013         mutex_unlock(&inode->i_mutex);
5014         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
5015         return ret;
5016 }
5017
5018 /*
5019  * This function convert a range of blocks to written extents
5020  * The caller of this function will pass the start offset and the size.
5021  * all unwritten extents within this range will be converted to
5022  * written extents.
5023  *
5024  * This function is called from the direct IO end io call back
5025  * function, to convert the fallocated extents after IO is completed.
5026  * Returns 0 on success.
5027  */
5028 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
5029                                    loff_t offset, ssize_t len)
5030 {
5031         unsigned int max_blocks;
5032         int ret = 0;
5033         int ret2 = 0;
5034         struct ext4_map_blocks map;
5035         unsigned int credits, blkbits = inode->i_blkbits;
5036
5037         map.m_lblk = offset >> blkbits;
5038         /*
5039          * We can't just convert len to max_blocks because
5040          * If blocksize = 4096 offset = 3072 and len = 2048
5041          */
5042         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
5043                       map.m_lblk);
5044         /*
5045          * This is somewhat ugly but the idea is clear: When transaction is
5046          * reserved, everything goes into it. Otherwise we rather start several
5047          * smaller transactions for conversion of each extent separately.
5048          */
5049         if (handle) {
5050                 handle = ext4_journal_start_reserved(handle,
5051                                                      EXT4_HT_EXT_CONVERT);
5052                 if (IS_ERR(handle))
5053                         return PTR_ERR(handle);
5054                 credits = 0;
5055         } else {
5056                 /*
5057                  * credits to insert 1 extent into extent tree
5058                  */
5059                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5060         }
5061         while (ret >= 0 && ret < max_blocks) {
5062                 map.m_lblk += ret;
5063                 map.m_len = (max_blocks -= ret);
5064                 if (credits) {
5065                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5066                                                     credits);
5067                         if (IS_ERR(handle)) {
5068                                 ret = PTR_ERR(handle);
5069                                 break;
5070                         }
5071                 }
5072                 ret = ext4_map_blocks(handle, inode, &map,
5073                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5074                 if (ret <= 0)
5075                         ext4_warning(inode->i_sb,
5076                                      "inode #%lu: block %u: len %u: "
5077                                      "ext4_ext_map_blocks returned %d",
5078                                      inode->i_ino, map.m_lblk,
5079                                      map.m_len, ret);
5080                 ext4_mark_inode_dirty(handle, inode);
5081                 if (credits)
5082                         ret2 = ext4_journal_stop(handle);
5083                 if (ret <= 0 || ret2)
5084                         break;
5085         }
5086         if (!credits)
5087                 ret2 = ext4_journal_stop(handle);
5088         return ret > 0 ? ret2 : ret;
5089 }
5090
5091 /*
5092  * If newes is not existing extent (newes->ec_pblk equals zero) find
5093  * delayed extent at start of newes and update newes accordingly and
5094  * return start of the next delayed extent.
5095  *
5096  * If newes is existing extent (newes->ec_pblk is not equal zero)
5097  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5098  * extent found. Leave newes unmodified.
5099  */
5100 static int ext4_find_delayed_extent(struct inode *inode,
5101                                     struct extent_status *newes)
5102 {
5103         struct extent_status es;
5104         ext4_lblk_t block, next_del;
5105
5106         if (newes->es_pblk == 0) {
5107                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5108                                 newes->es_lblk + newes->es_len - 1, &es);
5109
5110                 /*
5111                  * No extent in extent-tree contains block @newes->es_pblk,
5112                  * then the block may stay in 1)a hole or 2)delayed-extent.
5113                  */
5114                 if (es.es_len == 0)
5115                         /* A hole found. */
5116                         return 0;
5117
5118                 if (es.es_lblk > newes->es_lblk) {
5119                         /* A hole found. */
5120                         newes->es_len = min(es.es_lblk - newes->es_lblk,
5121                                             newes->es_len);
5122                         return 0;
5123                 }
5124
5125                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5126         }
5127
5128         block = newes->es_lblk + newes->es_len;
5129         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5130         if (es.es_len == 0)
5131                 next_del = EXT_MAX_BLOCKS;
5132         else
5133                 next_del = es.es_lblk;
5134
5135         return next_del;
5136 }
5137 /* fiemap flags we can handle specified here */
5138 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5139
5140 static int ext4_xattr_fiemap(struct inode *inode,
5141                                 struct fiemap_extent_info *fieinfo)
5142 {
5143         __u64 physical = 0;
5144         __u64 length;
5145         __u32 flags = FIEMAP_EXTENT_LAST;
5146         int blockbits = inode->i_sb->s_blocksize_bits;
5147         int error = 0;
5148
5149         /* in-inode? */
5150         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5151                 struct ext4_iloc iloc;
5152                 int offset;     /* offset of xattr in inode */
5153
5154                 error = ext4_get_inode_loc(inode, &iloc);
5155                 if (error)
5156                         return error;
5157                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5158                 offset = EXT4_GOOD_OLD_INODE_SIZE +
5159                                 EXT4_I(inode)->i_extra_isize;
5160                 physical += offset;
5161                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5162                 flags |= FIEMAP_EXTENT_DATA_INLINE;
5163                 brelse(iloc.bh);
5164         } else { /* external block */
5165                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5166                 length = inode->i_sb->s_blocksize;
5167         }
5168
5169         if (physical)
5170                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5171                                                 length, flags);
5172         return (error < 0 ? error : 0);
5173 }
5174
5175 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5176                 __u64 start, __u64 len)
5177 {
5178         ext4_lblk_t start_blk;
5179         int error = 0;
5180
5181         if (ext4_has_inline_data(inode)) {
5182                 int has_inline = 1;
5183
5184                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5185                                                 start, len);
5186
5187                 if (has_inline)
5188                         return error;
5189         }
5190
5191         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5192                 error = ext4_ext_precache(inode);
5193                 if (error)
5194                         return error;
5195         }
5196
5197         /* fallback to generic here if not in extents fmt */
5198         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5199                 return generic_block_fiemap(inode, fieinfo, start, len,
5200                         ext4_get_block);
5201
5202         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5203                 return -EBADR;
5204
5205         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5206                 error = ext4_xattr_fiemap(inode, fieinfo);
5207         } else {
5208                 ext4_lblk_t len_blks;
5209                 __u64 last_blk;
5210
5211                 start_blk = start >> inode->i_sb->s_blocksize_bits;
5212                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5213                 if (last_blk >= EXT_MAX_BLOCKS)
5214                         last_blk = EXT_MAX_BLOCKS-1;
5215                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5216
5217                 /*
5218                  * Walk the extent tree gathering extent information
5219                  * and pushing extents back to the user.
5220                  */
5221                 error = ext4_fill_fiemap_extents(inode, start_blk,
5222                                                  len_blks, fieinfo);
5223         }
5224         return error;
5225 }
5226
5227 /*
5228  * ext4_access_path:
5229  * Function to access the path buffer for marking it dirty.
5230  * It also checks if there are sufficient credits left in the journal handle
5231  * to update path.
5232  */
5233 static int
5234 ext4_access_path(handle_t *handle, struct inode *inode,
5235                 struct ext4_ext_path *path)
5236 {
5237         int credits, err;
5238
5239         if (!ext4_handle_valid(handle))
5240                 return 0;
5241
5242         /*
5243          * Check if need to extend journal credits
5244          * 3 for leaf, sb, and inode plus 2 (bmap and group
5245          * descriptor) for each block group; assume two block
5246          * groups
5247          */
5248         if (handle->h_buffer_credits < 7) {
5249                 credits = ext4_writepage_trans_blocks(inode);
5250                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5251                 /* EAGAIN is success */
5252                 if (err && err != -EAGAIN)
5253                         return err;
5254         }
5255
5256         err = ext4_ext_get_access(handle, inode, path);
5257         return err;
5258 }
5259
5260 /*
5261  * ext4_ext_shift_path_extents:
5262  * Shift the extents of a path structure lying between path[depth].p_ext
5263  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5264  * if it is right shift or left shift operation.
5265  */
5266 static int
5267 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5268                             struct inode *inode, handle_t *handle,
5269                             enum SHIFT_DIRECTION SHIFT)
5270 {
5271         int depth, err = 0;
5272         struct ext4_extent *ex_start, *ex_last;
5273         bool update = 0;
5274         depth = path->p_depth;
5275
5276         while (depth >= 0) {
5277                 if (depth == path->p_depth) {
5278                         ex_start = path[depth].p_ext;
5279                         if (!ex_start)
5280                                 return -EFSCORRUPTED;
5281
5282                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5283
5284                         err = ext4_access_path(handle, inode, path + depth);
5285                         if (err)
5286                                 goto out;
5287
5288                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5289                                 update = 1;
5290
5291                         while (ex_start <= ex_last) {
5292                                 if (SHIFT == SHIFT_LEFT) {
5293                                         le32_add_cpu(&ex_start->ee_block,
5294                                                 -shift);
5295                                         /* Try to merge to the left. */
5296                                         if ((ex_start >
5297                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5298                                             &&
5299                                             ext4_ext_try_to_merge_right(inode,
5300                                             path, ex_start - 1))
5301                                                 ex_last--;
5302                                         else
5303                                                 ex_start++;
5304                                 } else {
5305                                         le32_add_cpu(&ex_last->ee_block, shift);
5306                                         ext4_ext_try_to_merge_right(inode, path,
5307                                                 ex_last);
5308                                         ex_last--;
5309                                 }
5310                         }
5311                         err = ext4_ext_dirty(handle, inode, path + depth);
5312                         if (err)
5313                                 goto out;
5314
5315                         if (--depth < 0 || !update)
5316                                 break;
5317                 }
5318
5319                 /* Update index too */
5320                 err = ext4_access_path(handle, inode, path + depth);
5321                 if (err)
5322                         goto out;
5323
5324                 if (SHIFT == SHIFT_LEFT)
5325                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5326                 else
5327                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5328                 err = ext4_ext_dirty(handle, inode, path + depth);
5329                 if (err)
5330                         goto out;
5331
5332                 /* we are done if current index is not a starting index */
5333                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5334                         break;
5335
5336                 depth--;
5337         }
5338
5339 out:
5340         return err;
5341 }
5342
5343 /*
5344  * ext4_ext_shift_extents:
5345  * All the extents which lies in the range from @start to the last allocated
5346  * block for the @inode are shifted either towards left or right (depending
5347  * upon @SHIFT) by @shift blocks.
5348  * On success, 0 is returned, error otherwise.
5349  */
5350 static int
5351 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5352                        ext4_lblk_t start, ext4_lblk_t shift,
5353                        enum SHIFT_DIRECTION SHIFT)
5354 {
5355         struct ext4_ext_path *path;
5356         int ret = 0, depth;
5357         struct ext4_extent *extent;
5358         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5359
5360         /* Let path point to the last extent */
5361         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
5362         if (IS_ERR(path))
5363                 return PTR_ERR(path);
5364
5365         depth = path->p_depth;
5366         extent = path[depth].p_ext;
5367         if (!extent)
5368                 goto out;
5369
5370         stop = le32_to_cpu(extent->ee_block) +
5371                         ext4_ext_get_actual_len(extent);
5372
5373        /*
5374          * In case of left shift, Don't start shifting extents until we make
5375          * sure the hole is big enough to accommodate the shift.
5376         */
5377         if (SHIFT == SHIFT_LEFT) {
5378                 path = ext4_find_extent(inode, start - 1, &path, 0);
5379                 if (IS_ERR(path))
5380                         return PTR_ERR(path);
5381                 depth = path->p_depth;
5382                 extent =  path[depth].p_ext;
5383                 if (extent) {
5384                         ex_start = le32_to_cpu(extent->ee_block);
5385                         ex_end = le32_to_cpu(extent->ee_block) +
5386                                 ext4_ext_get_actual_len(extent);
5387                 } else {
5388                         ex_start = 0;
5389                         ex_end = 0;
5390                 }
5391
5392                 if ((start == ex_start && shift > ex_start) ||
5393                     (shift > start - ex_end)) {
5394                         ext4_ext_drop_refs(path);
5395                         kfree(path);
5396                         return -EINVAL;
5397                 }
5398         }
5399
5400         /*
5401          * In case of left shift, iterator points to start and it is increased
5402          * till we reach stop. In case of right shift, iterator points to stop
5403          * and it is decreased till we reach start.
5404          */
5405         if (SHIFT == SHIFT_LEFT)
5406                 iterator = &start;
5407         else
5408                 iterator = &stop;
5409
5410         /* Its safe to start updating extents */
5411         while (start < stop) {
5412                 path = ext4_find_extent(inode, *iterator, &path, 0);
5413                 if (IS_ERR(path))
5414                         return PTR_ERR(path);
5415                 depth = path->p_depth;
5416                 extent = path[depth].p_ext;
5417                 if (!extent) {
5418                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5419                                          (unsigned long) *iterator);
5420                         return -EFSCORRUPTED;
5421                 }
5422                 if (SHIFT == SHIFT_LEFT && *iterator >
5423                     le32_to_cpu(extent->ee_block)) {
5424                         /* Hole, move to the next extent */
5425                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5426                                 path[depth].p_ext++;
5427                         } else {
5428                                 *iterator = ext4_ext_next_allocated_block(path);
5429                                 continue;
5430                         }
5431                 }
5432
5433                 if (SHIFT == SHIFT_LEFT) {
5434                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5435                         *iterator = le32_to_cpu(extent->ee_block) +
5436                                         ext4_ext_get_actual_len(extent);
5437                 } else {
5438                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5439                         *iterator =  le32_to_cpu(extent->ee_block) > 0 ?
5440                                 le32_to_cpu(extent->ee_block) - 1 : 0;
5441                         /* Update path extent in case we need to stop */
5442                         while (le32_to_cpu(extent->ee_block) < start)
5443                                 extent++;
5444                         path[depth].p_ext = extent;
5445                 }
5446                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5447                                 handle, SHIFT);
5448                 if (ret)
5449                         break;
5450         }
5451 out:
5452         ext4_ext_drop_refs(path);
5453         kfree(path);
5454         return ret;
5455 }
5456
5457 /*
5458  * ext4_collapse_range:
5459  * This implements the fallocate's collapse range functionality for ext4
5460  * Returns: 0 and non-zero on error.
5461  */
5462 int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5463 {
5464         struct super_block *sb = inode->i_sb;
5465         ext4_lblk_t punch_start, punch_stop;
5466         handle_t *handle;
5467         unsigned int credits;
5468         loff_t new_size, ioffset;
5469         int ret;
5470
5471         /*
5472          * We need to test this early because xfstests assumes that a
5473          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5474          * system does not support collapse range.
5475          */
5476         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5477                 return -EOPNOTSUPP;
5478
5479         /* Collapse range works only on fs block size aligned offsets. */
5480         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5481             len & (EXT4_CLUSTER_SIZE(sb) - 1))
5482                 return -EINVAL;
5483
5484         if (!S_ISREG(inode->i_mode))
5485                 return -EINVAL;
5486
5487         trace_ext4_collapse_range(inode, offset, len);
5488
5489         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5490         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5491
5492         /* Call ext4_force_commit to flush all data in case of data=journal. */
5493         if (ext4_should_journal_data(inode)) {
5494                 ret = ext4_force_commit(inode->i_sb);
5495                 if (ret)
5496                         return ret;
5497         }
5498
5499         mutex_lock(&inode->i_mutex);
5500         /*
5501          * There is no need to overlap collapse range with EOF, in which case
5502          * it is effectively a truncate operation
5503          */
5504         if (offset + len >= i_size_read(inode)) {
5505                 ret = -EINVAL;
5506                 goto out_mutex;
5507         }
5508
5509         /* Currently just for extent based files */
5510         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5511                 ret = -EOPNOTSUPP;
5512                 goto out_mutex;
5513         }
5514
5515         /* Wait for existing dio to complete */
5516         ext4_inode_block_unlocked_dio(inode);
5517         inode_dio_wait(inode);
5518
5519         /*
5520          * Prevent page faults from reinstantiating pages we have released from
5521          * page cache.
5522          */
5523         down_write(&EXT4_I(inode)->i_mmap_sem);
5524         /*
5525          * Need to round down offset to be aligned with page size boundary
5526          * for page size > block size.
5527          */
5528         ioffset = round_down(offset, PAGE_SIZE);
5529         /*
5530          * Write tail of the last page before removed range since it will get
5531          * removed from the page cache below.
5532          */
5533         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5534         if (ret)
5535                 goto out_mmap;
5536         /*
5537          * Write data that will be shifted to preserve them when discarding
5538          * page cache below. We are also protected from pages becoming dirty
5539          * by i_mmap_sem.
5540          */
5541         ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5542                                            LLONG_MAX);
5543         if (ret)
5544                 goto out_mmap;
5545         truncate_pagecache(inode, ioffset);
5546
5547         credits = ext4_writepage_trans_blocks(inode);
5548         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5549         if (IS_ERR(handle)) {
5550                 ret = PTR_ERR(handle);
5551                 goto out_mmap;
5552         }
5553
5554         down_write(&EXT4_I(inode)->i_data_sem);
5555         ext4_discard_preallocations(inode);
5556
5557         ret = ext4_es_remove_extent(inode, punch_start,
5558                                     EXT_MAX_BLOCKS - punch_start);
5559         if (ret) {
5560                 up_write(&EXT4_I(inode)->i_data_sem);
5561                 goto out_stop;
5562         }
5563
5564         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5565         if (ret) {
5566                 up_write(&EXT4_I(inode)->i_data_sem);
5567                 goto out_stop;
5568         }
5569         ext4_discard_preallocations(inode);
5570
5571         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5572                                      punch_stop - punch_start, SHIFT_LEFT);
5573         if (ret) {
5574                 up_write(&EXT4_I(inode)->i_data_sem);
5575                 goto out_stop;
5576         }
5577
5578         new_size = i_size_read(inode) - len;
5579         i_size_write(inode, new_size);
5580         EXT4_I(inode)->i_disksize = new_size;
5581
5582         up_write(&EXT4_I(inode)->i_data_sem);
5583         if (IS_SYNC(inode))
5584                 ext4_handle_sync(handle);
5585         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5586         ext4_mark_inode_dirty(handle, inode);
5587
5588 out_stop:
5589         ext4_journal_stop(handle);
5590 out_mmap:
5591         up_write(&EXT4_I(inode)->i_mmap_sem);
5592         ext4_inode_resume_unlocked_dio(inode);
5593 out_mutex:
5594         mutex_unlock(&inode->i_mutex);
5595         return ret;
5596 }
5597
5598 /*
5599  * ext4_insert_range:
5600  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5601  * The data blocks starting from @offset to the EOF are shifted by @len
5602  * towards right to create a hole in the @inode. Inode size is increased
5603  * by len bytes.
5604  * Returns 0 on success, error otherwise.
5605  */
5606 int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5607 {
5608         struct super_block *sb = inode->i_sb;
5609         handle_t *handle;
5610         struct ext4_ext_path *path;
5611         struct ext4_extent *extent;
5612         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5613         unsigned int credits, ee_len;
5614         int ret = 0, depth, split_flag = 0;
5615         loff_t ioffset;
5616
5617         /*
5618          * We need to test this early because xfstests assumes that an
5619          * insert range of (0, 1) will return EOPNOTSUPP if the file
5620          * system does not support insert range.
5621          */
5622         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5623                 return -EOPNOTSUPP;
5624
5625         /* Insert range works only on fs block size aligned offsets. */
5626         if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5627                         len & (EXT4_CLUSTER_SIZE(sb) - 1))
5628                 return -EINVAL;
5629
5630         if (!S_ISREG(inode->i_mode))
5631                 return -EOPNOTSUPP;
5632
5633         trace_ext4_insert_range(inode, offset, len);
5634
5635         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5636         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5637
5638         /* Call ext4_force_commit to flush all data in case of data=journal */
5639         if (ext4_should_journal_data(inode)) {
5640                 ret = ext4_force_commit(inode->i_sb);
5641                 if (ret)
5642                         return ret;
5643         }
5644
5645         mutex_lock(&inode->i_mutex);
5646         /* Currently just for extent based files */
5647         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5648                 ret = -EOPNOTSUPP;
5649                 goto out_mutex;
5650         }
5651
5652         /* Check for wrap through zero */
5653         if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5654                 ret = -EFBIG;
5655                 goto out_mutex;
5656         }
5657
5658         /* Offset should be less than i_size */
5659         if (offset >= i_size_read(inode)) {
5660                 ret = -EINVAL;
5661                 goto out_mutex;
5662         }
5663
5664         /* Wait for existing dio to complete */
5665         ext4_inode_block_unlocked_dio(inode);
5666         inode_dio_wait(inode);
5667
5668         /*
5669          * Prevent page faults from reinstantiating pages we have released from
5670          * page cache.
5671          */
5672         down_write(&EXT4_I(inode)->i_mmap_sem);
5673         /*
5674          * Need to round down to align start offset to page size boundary
5675          * for page size > block size.
5676          */
5677         ioffset = round_down(offset, PAGE_SIZE);
5678         /* Write out all dirty pages */
5679         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5680                         LLONG_MAX);
5681         if (ret)
5682                 goto out_mmap;
5683         truncate_pagecache(inode, ioffset);
5684
5685         credits = ext4_writepage_trans_blocks(inode);
5686         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5687         if (IS_ERR(handle)) {
5688                 ret = PTR_ERR(handle);
5689                 goto out_mmap;
5690         }
5691
5692         /* Expand file to avoid data loss if there is error while shifting */
5693         inode->i_size += len;
5694         EXT4_I(inode)->i_disksize += len;
5695         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5696         ret = ext4_mark_inode_dirty(handle, inode);
5697         if (ret)
5698                 goto out_stop;
5699
5700         down_write(&EXT4_I(inode)->i_data_sem);
5701         ext4_discard_preallocations(inode);
5702
5703         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5704         if (IS_ERR(path)) {
5705                 up_write(&EXT4_I(inode)->i_data_sem);
5706                 goto out_stop;
5707         }
5708
5709         depth = ext_depth(inode);
5710         extent = path[depth].p_ext;
5711         if (extent) {
5712                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5713                 ee_len = ext4_ext_get_actual_len(extent);
5714
5715                 /*
5716                  * If offset_lblk is not the starting block of extent, split
5717                  * the extent @offset_lblk
5718                  */
5719                 if ((offset_lblk > ee_start_lblk) &&
5720                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5721                         if (ext4_ext_is_unwritten(extent))
5722                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5723                                         EXT4_EXT_MARK_UNWRIT2;
5724                         ret = ext4_split_extent_at(handle, inode, &path,
5725                                         offset_lblk, split_flag,
5726                                         EXT4_EX_NOCACHE |
5727                                         EXT4_GET_BLOCKS_PRE_IO |
5728                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5729                 }
5730
5731                 ext4_ext_drop_refs(path);
5732                 kfree(path);
5733                 if (ret < 0) {
5734                         up_write(&EXT4_I(inode)->i_data_sem);
5735                         goto out_stop;
5736                 }
5737         }
5738
5739         ret = ext4_es_remove_extent(inode, offset_lblk,
5740                         EXT_MAX_BLOCKS - offset_lblk);
5741         if (ret) {
5742                 up_write(&EXT4_I(inode)->i_data_sem);
5743                 goto out_stop;
5744         }
5745
5746         /*
5747          * if offset_lblk lies in a hole which is at start of file, use
5748          * ee_start_lblk to shift extents
5749          */
5750         ret = ext4_ext_shift_extents(inode, handle,
5751                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5752                 len_lblk, SHIFT_RIGHT);
5753
5754         up_write(&EXT4_I(inode)->i_data_sem);
5755         if (IS_SYNC(inode))
5756                 ext4_handle_sync(handle);
5757
5758 out_stop:
5759         ext4_journal_stop(handle);
5760 out_mmap:
5761         up_write(&EXT4_I(inode)->i_mmap_sem);
5762         ext4_inode_resume_unlocked_dio(inode);
5763 out_mutex:
5764         mutex_unlock(&inode->i_mutex);
5765         return ret;
5766 }
5767
5768 /**
5769  * ext4_swap_extents - Swap extents between two inodes
5770  *
5771  * @inode1:     First inode
5772  * @inode2:     Second inode
5773  * @lblk1:      Start block for first inode
5774  * @lblk2:      Start block for second inode
5775  * @count:      Number of blocks to swap
5776  * @mark_unwritten: Mark second inode's extents as unwritten after swap
5777  * @erp:        Pointer to save error value
5778  *
5779  * This helper routine does exactly what is promise "swap extents". All other
5780  * stuff such as page-cache locking consistency, bh mapping consistency or
5781  * extent's data copying must be performed by caller.
5782  * Locking:
5783  *              i_mutex is held for both inodes
5784  *              i_data_sem is locked for write for both inodes
5785  * Assumptions:
5786  *              All pages from requested range are locked for both inodes
5787  */
5788 int
5789 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5790                      struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5791                   ext4_lblk_t count, int unwritten, int *erp)
5792 {
5793         struct ext4_ext_path *path1 = NULL;
5794         struct ext4_ext_path *path2 = NULL;
5795         int replaced_count = 0;
5796
5797         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5798         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5799         BUG_ON(!mutex_is_locked(&inode1->i_mutex));
5800         BUG_ON(!mutex_is_locked(&inode2->i_mutex));
5801
5802         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5803         if (unlikely(*erp))
5804                 return 0;
5805         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5806         if (unlikely(*erp))
5807                 return 0;
5808
5809         while (count) {
5810                 struct ext4_extent *ex1, *ex2, tmp_ex;
5811                 ext4_lblk_t e1_blk, e2_blk;
5812                 int e1_len, e2_len, len;
5813                 int split = 0;
5814
5815                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5816                 if (IS_ERR(path1)) {
5817                         *erp = PTR_ERR(path1);
5818                         path1 = NULL;
5819                 finish:
5820                         count = 0;
5821                         goto repeat;
5822                 }
5823                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5824                 if (IS_ERR(path2)) {
5825                         *erp = PTR_ERR(path2);
5826                         path2 = NULL;
5827                         goto finish;
5828                 }
5829                 ex1 = path1[path1->p_depth].p_ext;
5830                 ex2 = path2[path2->p_depth].p_ext;
5831                 /* Do we have somthing to swap ? */
5832                 if (unlikely(!ex2 || !ex1))
5833                         goto finish;
5834
5835                 e1_blk = le32_to_cpu(ex1->ee_block);
5836                 e2_blk = le32_to_cpu(ex2->ee_block);
5837                 e1_len = ext4_ext_get_actual_len(ex1);
5838                 e2_len = ext4_ext_get_actual_len(ex2);
5839
5840                 /* Hole handling */
5841                 if (!in_range(lblk1, e1_blk, e1_len) ||
5842                     !in_range(lblk2, e2_blk, e2_len)) {
5843                         ext4_lblk_t next1, next2;
5844
5845                         /* if hole after extent, then go to next extent */
5846                         next1 = ext4_ext_next_allocated_block(path1);
5847                         next2 = ext4_ext_next_allocated_block(path2);
5848                         /* If hole before extent, then shift to that extent */
5849                         if (e1_blk > lblk1)
5850                                 next1 = e1_blk;
5851                         if (e2_blk > lblk2)
5852                                 next2 = e1_blk;
5853                         /* Do we have something to swap */
5854                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5855                                 goto finish;
5856                         /* Move to the rightest boundary */
5857                         len = next1 - lblk1;
5858                         if (len < next2 - lblk2)
5859                                 len = next2 - lblk2;
5860                         if (len > count)
5861                                 len = count;
5862                         lblk1 += len;
5863                         lblk2 += len;
5864                         count -= len;
5865                         goto repeat;
5866                 }
5867
5868                 /* Prepare left boundary */
5869                 if (e1_blk < lblk1) {
5870                         split = 1;
5871                         *erp = ext4_force_split_extent_at(handle, inode1,
5872                                                 &path1, lblk1, 0);
5873                         if (unlikely(*erp))
5874                                 goto finish;
5875                 }
5876                 if (e2_blk < lblk2) {
5877                         split = 1;
5878                         *erp = ext4_force_split_extent_at(handle, inode2,
5879                                                 &path2,  lblk2, 0);
5880                         if (unlikely(*erp))
5881                                 goto finish;
5882                 }
5883                 /* ext4_split_extent_at() may result in leaf extent split,
5884                  * path must to be revalidated. */
5885                 if (split)
5886                         goto repeat;
5887
5888                 /* Prepare right boundary */
5889                 len = count;
5890                 if (len > e1_blk + e1_len - lblk1)
5891                         len = e1_blk + e1_len - lblk1;
5892                 if (len > e2_blk + e2_len - lblk2)
5893                         len = e2_blk + e2_len - lblk2;
5894
5895                 if (len != e1_len) {
5896                         split = 1;
5897                         *erp = ext4_force_split_extent_at(handle, inode1,
5898                                                 &path1, lblk1 + len, 0);
5899                         if (unlikely(*erp))
5900                                 goto finish;
5901                 }
5902                 if (len != e2_len) {
5903                         split = 1;
5904                         *erp = ext4_force_split_extent_at(handle, inode2,
5905                                                 &path2, lblk2 + len, 0);
5906                         if (*erp)
5907                                 goto finish;
5908                 }
5909                 /* ext4_split_extent_at() may result in leaf extent split,
5910                  * path must to be revalidated. */
5911                 if (split)
5912                         goto repeat;
5913
5914                 BUG_ON(e2_len != e1_len);
5915                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5916                 if (unlikely(*erp))
5917                         goto finish;
5918                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5919                 if (unlikely(*erp))
5920                         goto finish;
5921
5922                 /* Both extents are fully inside boundaries. Swap it now */
5923                 tmp_ex = *ex1;
5924                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5925                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5926                 ex1->ee_len = cpu_to_le16(e2_len);
5927                 ex2->ee_len = cpu_to_le16(e1_len);
5928                 if (unwritten)
5929                         ext4_ext_mark_unwritten(ex2);
5930                 if (ext4_ext_is_unwritten(&tmp_ex))
5931                         ext4_ext_mark_unwritten(ex1);
5932
5933                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5934                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5935                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5936                                       path2->p_depth);
5937                 if (unlikely(*erp))
5938                         goto finish;
5939                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5940                                       path1->p_depth);
5941                 /*
5942                  * Looks scarry ah..? second inode already points to new blocks,
5943                  * and it was successfully dirtied. But luckily error may happen
5944                  * only due to journal error, so full transaction will be
5945                  * aborted anyway.
5946                  */
5947                 if (unlikely(*erp))
5948                         goto finish;
5949                 lblk1 += len;
5950                 lblk2 += len;
5951                 replaced_count += len;
5952                 count -= len;
5953
5954         repeat:
5955                 ext4_ext_drop_refs(path1);
5956                 kfree(path1);
5957                 ext4_ext_drop_refs(path2);
5958                 kfree(path2);
5959                 path1 = path2 = NULL;
5960         }
5961         return replaced_count;
5962 }