linux/fs/ext4/extents.c
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   1/*
   2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3 * Written by Alex Tomas <alex@clusterfs.com>
   4 *
   5 * Architecture independence:
   6 *   Copyright (c) 2005, Bull S.A.
   7 *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License version 2 as
  11 * published by the Free Software Foundation.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21 */
  22
  23/*
  24 * Extents support for EXT4
  25 *
  26 * TODO:
  27 *   - ext4*_error() should be used in some situations
  28 *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29 *   - smart tree reduction
  30 */
  31
  32#include <linux/fs.h>
  33#include <linux/time.h>
  34#include <linux/jbd2.h>
  35#include <linux/highuid.h>
  36#include <linux/pagemap.h>
  37#include <linux/quotaops.h>
  38#include <linux/string.h>
  39#include <linux/slab.h>
  40#include <linux/uaccess.h>
  41#include <linux/fiemap.h>
  42#include <linux/backing-dev.h>
  43#include "ext4_jbd2.h"
  44#include "ext4_extents.h"
  45#include "xattr.h"
  46
  47#include <trace/events/ext4.h>
  48
  49/*
  50 * used by extent splitting.
  51 */
  52#define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  53                                        due to ENOSPC */
  54#define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  55#define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  56
  57#define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  58#define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  59
  60static __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
  72static 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
  86static 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
  98static 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
 105static 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
 112static int ext4_find_delayed_extent(struct inode *inode,
 113                                    struct extent_status *newes);
 114
 115static int ext4_ext_truncate_extend_restart(handle_t *handle,
 116                                            struct inode *inode,
 117                                            int needed)
 118{
 119        int err;
 120
 121        if (!ext4_handle_valid(handle))
 122                return 0;
 123        if (handle->h_buffer_credits >= needed)
 124                return 0;
 125        /*
 126         * If we need to extend the journal get a few extra blocks
 127         * while we're at it for efficiency's sake.
 128         */
 129        needed += 3;
 130        err = ext4_journal_extend(handle, needed - handle->h_buffer_credits);
 131        if (err <= 0)
 132                return err;
 133        err = ext4_truncate_restart_trans(handle, inode, needed);
 134        if (err == 0)
 135                err = -EAGAIN;
 136
 137        return err;
 138}
 139
 140/*
 141 * could return:
 142 *  - EROFS
 143 *  - ENOMEM
 144 */
 145static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 146                                struct ext4_ext_path *path)
 147{
 148        if (path->p_bh) {
 149                /* path points to block */
 150                BUFFER_TRACE(path->p_bh, "get_write_access");
 151                return ext4_journal_get_write_access(handle, path->p_bh);
 152        }
 153        /* path points to leaf/index in inode body */
 154        /* we use in-core data, no need to protect them */
 155        return 0;
 156}
 157
 158/*
 159 * could return:
 160 *  - EROFS
 161 *  - ENOMEM
 162 *  - EIO
 163 */
 164int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 165                     struct inode *inode, struct ext4_ext_path *path)
 166{
 167        int err;
 168
 169        WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 170        if (path->p_bh) {
 171                ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 172                /* path points to block */
 173                err = __ext4_handle_dirty_metadata(where, line, handle,
 174                                                   inode, path->p_bh);
 175        } else {
 176                /* path points to leaf/index in inode body */
 177                err = ext4_mark_inode_dirty(handle, inode);
 178        }
 179        return err;
 180}
 181
 182static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 183                              struct ext4_ext_path *path,
 184                              ext4_lblk_t block)
 185{
 186        if (path) {
 187                int depth = path->p_depth;
 188                struct ext4_extent *ex;
 189
 190                /*
 191                 * Try to predict block placement assuming that we are
 192                 * filling in a file which will eventually be
 193                 * non-sparse --- i.e., in the case of libbfd writing
 194                 * an ELF object sections out-of-order but in a way
 195                 * the eventually results in a contiguous object or
 196                 * executable file, or some database extending a table
 197                 * space file.  However, this is actually somewhat
 198                 * non-ideal if we are writing a sparse file such as
 199                 * qemu or KVM writing a raw image file that is going
 200                 * to stay fairly sparse, since it will end up
 201                 * fragmenting the file system's free space.  Maybe we
 202                 * should have some hueristics or some way to allow
 203                 * userspace to pass a hint to file system,
 204                 * especially if the latter case turns out to be
 205                 * common.
 206                 */
 207                ex = path[depth].p_ext;
 208                if (ex) {
 209                        ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 210                        ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 211
 212                        if (block > ext_block)
 213                                return ext_pblk + (block - ext_block);
 214                        else
 215                                return ext_pblk - (ext_block - block);
 216                }
 217
 218                /* it looks like index is empty;
 219                 * try to find starting block from index itself */
 220                if (path[depth].p_bh)
 221                        return path[depth].p_bh->b_blocknr;
 222        }
 223
 224        /* OK. use inode's group */
 225        return ext4_inode_to_goal_block(inode);
 226}
 227
 228/*
 229 * Allocation for a meta data block
 230 */
 231static ext4_fsblk_t
 232ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 233                        struct ext4_ext_path *path,
 234                        struct ext4_extent *ex, int *err, unsigned int flags)
 235{
 236        ext4_fsblk_t goal, newblock;
 237
 238        goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 239        newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 240                                        NULL, err);
 241        return newblock;
 242}
 243
 244static inline int ext4_ext_space_block(struct inode *inode, int check)
 245{
 246        int size;
 247
 248        size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 249                        / sizeof(struct ext4_extent);
 250#ifdef AGGRESSIVE_TEST
 251        if (!check && size > 6)
 252                size = 6;
 253#endif
 254        return size;
 255}
 256
 257static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 258{
 259        int size;
 260
 261        size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 262                        / sizeof(struct ext4_extent_idx);
 263#ifdef AGGRESSIVE_TEST
 264        if (!check && size > 5)
 265                size = 5;
 266#endif
 267        return size;
 268}
 269
 270static inline int ext4_ext_space_root(struct inode *inode, int check)
 271{
 272        int size;
 273
 274        size = sizeof(EXT4_I(inode)->i_data);
 275        size -= sizeof(struct ext4_extent_header);
 276        size /= sizeof(struct ext4_extent);
 277#ifdef AGGRESSIVE_TEST
 278        if (!check && size > 3)
 279                size = 3;
 280#endif
 281        return size;
 282}
 283
 284static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 285{
 286        int size;
 287
 288        size = sizeof(EXT4_I(inode)->i_data);
 289        size -= sizeof(struct ext4_extent_header);
 290        size /= sizeof(struct ext4_extent_idx);
 291#ifdef AGGRESSIVE_TEST
 292        if (!check && size > 4)
 293                size = 4;
 294#endif
 295        return size;
 296}
 297
 298static inline int
 299ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 300                           struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 301                           int nofail)
 302{
 303        struct ext4_ext_path *path = *ppath;
 304        int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 305
 306        return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 307                        EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 308                        EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
 309                        (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
 310}
 311
 312/*
 313 * Calculate the number of metadata blocks needed
 314 * to allocate @blocks
 315 * Worse case is one block per extent
 316 */
 317int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 318{
 319        struct ext4_inode_info *ei = EXT4_I(inode);
 320        int idxs;
 321
 322        idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 323                / sizeof(struct ext4_extent_idx));
 324
 325        /*
 326         * If the new delayed allocation block is contiguous with the
 327         * previous da block, it can share index blocks with the
 328         * previous block, so we only need to allocate a new index
 329         * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 330         * an additional index block, and at ldxs**3 blocks, yet
 331         * another index blocks.
 332         */
 333        if (ei->i_da_metadata_calc_len &&
 334            ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 335                int num = 0;
 336
 337                if ((ei->i_da_metadata_calc_len % idxs) == 0)
 338                        num++;
 339                if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 340                        num++;
 341                if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 342                        num++;
 343                        ei->i_da_metadata_calc_len = 0;
 344                } else
 345                        ei->i_da_metadata_calc_len++;
 346                ei->i_da_metadata_calc_last_lblock++;
 347                return num;
 348        }
 349
 350        /*
 351         * In the worst case we need a new set of index blocks at
 352         * every level of the inode's extent tree.
 353         */
 354        ei->i_da_metadata_calc_len = 1;
 355        ei->i_da_metadata_calc_last_lblock = lblock;
 356        return ext_depth(inode) + 1;
 357}
 358
 359static int
 360ext4_ext_max_entries(struct inode *inode, int depth)
 361{
 362        int max;
 363
 364        if (depth == ext_depth(inode)) {
 365                if (depth == 0)
 366                        max = ext4_ext_space_root(inode, 1);
 367                else
 368                        max = ext4_ext_space_root_idx(inode, 1);
 369        } else {
 370                if (depth == 0)
 371                        max = ext4_ext_space_block(inode, 1);
 372                else
 373                        max = ext4_ext_space_block_idx(inode, 1);
 374        }
 375
 376        return max;
 377}
 378
 379static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 380{
 381        ext4_fsblk_t block = ext4_ext_pblock(ext);
 382        int len = ext4_ext_get_actual_len(ext);
 383        ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 384
 385        /*
 386         * We allow neither:
 387         *  - zero length
 388         *  - overflow/wrap-around
 389         */
 390        if (lblock + len <= lblock)
 391                return 0;
 392        return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 393}
 394
 395static int ext4_valid_extent_idx(struct inode *inode,
 396                                struct ext4_extent_idx *ext_idx)
 397{
 398        ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 399
 400        return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 401}
 402
 403static int ext4_valid_extent_entries(struct inode *inode,
 404                                struct ext4_extent_header *eh,
 405                                int depth)
 406{
 407        unsigned short entries;
 408        if (eh->eh_entries == 0)
 409                return 1;
 410
 411        entries = le16_to_cpu(eh->eh_entries);
 412
 413        if (depth == 0) {
 414                /* leaf entries */
 415                struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 416                struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 417                ext4_fsblk_t pblock = 0;
 418                ext4_lblk_t lblock = 0;
 419                ext4_lblk_t prev = 0;
 420                int len = 0;
 421                while (entries) {
 422                        if (!ext4_valid_extent(inode, ext))
 423                                return 0;
 424
 425                        /* Check for overlapping extents */
 426                        lblock = le32_to_cpu(ext->ee_block);
 427                        len = ext4_ext_get_actual_len(ext);
 428                        if ((lblock <= prev) && prev) {
 429                                pblock = ext4_ext_pblock(ext);
 430                                es->s_last_error_block = cpu_to_le64(pblock);
 431                                return 0;
 432                        }
 433                        ext++;
 434                        entries--;
 435                        prev = lblock + len - 1;
 436                }
 437        } else {
 438                struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 439                while (entries) {
 440                        if (!ext4_valid_extent_idx(inode, ext_idx))
 441                                return 0;
 442                        ext_idx++;
 443                        entries--;
 444                }
 445        }
 446        return 1;
 447}
 448
 449static int __ext4_ext_check(const char *function, unsigned int line,
 450                            struct inode *inode, struct ext4_extent_header *eh,
 451                            int depth, ext4_fsblk_t pblk)
 452{
 453        const char *error_msg;
 454        int max = 0, err = -EFSCORRUPTED;
 455
 456        if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 457                error_msg = "invalid magic";
 458                goto corrupted;
 459        }
 460        if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 461                error_msg = "unexpected eh_depth";
 462                goto corrupted;
 463        }
 464        if (unlikely(eh->eh_max == 0)) {
 465                error_msg = "invalid eh_max";
 466                goto corrupted;
 467        }
 468        max = ext4_ext_max_entries(inode, depth);
 469        if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 470                error_msg = "too large eh_max";
 471                goto corrupted;
 472        }
 473        if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 474                error_msg = "invalid eh_entries";
 475                goto corrupted;
 476        }
 477        if (!ext4_valid_extent_entries(inode, eh, depth)) {
 478                error_msg = "invalid extent entries";
 479                goto corrupted;
 480        }
 481        if (unlikely(depth > 32)) {
 482                error_msg = "too large eh_depth";
 483                goto corrupted;
 484        }
 485        /* Verify checksum on non-root extent tree nodes */
 486        if (ext_depth(inode) != depth &&
 487            !ext4_extent_block_csum_verify(inode, eh)) {
 488                error_msg = "extent tree corrupted";
 489                err = -EFSBADCRC;
 490                goto corrupted;
 491        }
 492        return 0;
 493
 494corrupted:
 495        ext4_error_inode(inode, function, line, 0,
 496                         "pblk %llu bad header/extent: %s - magic %x, "
 497                         "entries %u, max %u(%u), depth %u(%u)",
 498                         (unsigned long long) pblk, error_msg,
 499                         le16_to_cpu(eh->eh_magic),
 500                         le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 501                         max, le16_to_cpu(eh->eh_depth), depth);
 502        return err;
 503}
 504
 505#define ext4_ext_check(inode, eh, depth, pblk)                  \
 506        __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 507
 508int ext4_ext_check_inode(struct inode *inode)
 509{
 510        return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 511}
 512
 513static struct buffer_head *
 514__read_extent_tree_block(const char *function, unsigned int line,
 515                         struct inode *inode, ext4_fsblk_t pblk, int depth,
 516                         int flags)
 517{
 518        struct buffer_head              *bh;
 519        int                             err;
 520
 521        bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
 522        if (unlikely(!bh))
 523                return ERR_PTR(-ENOMEM);
 524
 525        if (!bh_uptodate_or_lock(bh)) {
 526                trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 527                err = bh_submit_read(bh);
 528                if (err < 0)
 529                        goto errout;
 530        }
 531        if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 532                return bh;
 533        err = __ext4_ext_check(function, line, inode,
 534                               ext_block_hdr(bh), depth, pblk);
 535        if (err)
 536                goto errout;
 537        set_buffer_verified(bh);
 538        /*
 539         * If this is a leaf block, cache all of its entries
 540         */
 541        if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 542                struct ext4_extent_header *eh = ext_block_hdr(bh);
 543                struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 544                ext4_lblk_t prev = 0;
 545                int i;
 546
 547                for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 548                        unsigned int status = EXTENT_STATUS_WRITTEN;
 549                        ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 550                        int len = ext4_ext_get_actual_len(ex);
 551
 552                        if (prev && (prev != lblk))
 553                                ext4_es_cache_extent(inode, prev,
 554                                                     lblk - prev, ~0,
 555                                                     EXTENT_STATUS_HOLE);
 556
 557                        if (ext4_ext_is_unwritten(ex))
 558                                status = EXTENT_STATUS_UNWRITTEN;
 559                        ext4_es_cache_extent(inode, lblk, len,
 560                                             ext4_ext_pblock(ex), status);
 561                        prev = lblk + len;
 562                }
 563        }
 564        return bh;
 565errout:
 566        put_bh(bh);
 567        return ERR_PTR(err);
 568
 569}
 570
 571#define read_extent_tree_block(inode, pblk, depth, flags)               \
 572        __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 573                                 (depth), (flags))
 574
 575/*
 576 * This function is called to cache a file's extent information in the
 577 * extent status tree
 578 */
 579int ext4_ext_precache(struct inode *inode)
 580{
 581        struct ext4_inode_info *ei = EXT4_I(inode);
 582        struct ext4_ext_path *path = NULL;
 583        struct buffer_head *bh;
 584        int i = 0, depth, ret = 0;
 585
 586        if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 587                return 0;       /* not an extent-mapped inode */
 588
 589        down_read(&ei->i_data_sem);
 590        depth = ext_depth(inode);
 591
 592        path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 593                       GFP_NOFS);
 594        if (path == NULL) {
 595                up_read(&ei->i_data_sem);
 596                return -ENOMEM;
 597        }
 598
 599        /* Don't cache anything if there are no external extent blocks */
 600        if (depth == 0)
 601                goto out;
 602        path[0].p_hdr = ext_inode_hdr(inode);
 603        ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 604        if (ret)
 605                goto out;
 606        path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 607        while (i >= 0) {
 608                /*
 609                 * If this is a leaf block or we've reached the end of
 610                 * the index block, go up
 611                 */
 612                if ((i == depth) ||
 613                    path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 614                        brelse(path[i].p_bh);
 615                        path[i].p_bh = NULL;
 616                        i--;
 617                        continue;
 618                }
 619                bh = read_extent_tree_block(inode,
 620                                            ext4_idx_pblock(path[i].p_idx++),
 621                                            depth - i - 1,
 622                                            EXT4_EX_FORCE_CACHE);
 623                if (IS_ERR(bh)) {
 624                        ret = PTR_ERR(bh);
 625                        break;
 626                }
 627                i++;
 628                path[i].p_bh = bh;
 629                path[i].p_hdr = ext_block_hdr(bh);
 630                path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 631        }
 632        ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 633out:
 634        up_read(&ei->i_data_sem);
 635        ext4_ext_drop_refs(path);
 636        kfree(path);
 637        return ret;
 638}
 639
 640#ifdef EXT_DEBUG
 641static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 642{
 643        int k, l = path->p_depth;
 644
 645        ext_debug("path:");
 646        for (k = 0; k <= l; k++, path++) {
 647                if (path->p_idx) {
 648                  ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 649                            ext4_idx_pblock(path->p_idx));
 650                } else if (path->p_ext) {
 651                        ext_debug("  %d:[%d]%d:%llu ",
 652                                  le32_to_cpu(path->p_ext->ee_block),
 653                                  ext4_ext_is_unwritten(path->p_ext),
 654                                  ext4_ext_get_actual_len(path->p_ext),
 655                                  ext4_ext_pblock(path->p_ext));
 656                } else
 657                        ext_debug("  []");
 658        }
 659        ext_debug("\n");
 660}
 661
 662static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 663{
 664        int depth = ext_depth(inode);
 665        struct ext4_extent_header *eh;
 666        struct ext4_extent *ex;
 667        int i;
 668
 669        if (!path)
 670                return;
 671
 672        eh = path[depth].p_hdr;
 673        ex = EXT_FIRST_EXTENT(eh);
 674
 675        ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 676
 677        for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 678                ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 679                          ext4_ext_is_unwritten(ex),
 680                          ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 681        }
 682        ext_debug("\n");
 683}
 684
 685static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 686                        ext4_fsblk_t newblock, int level)
 687{
 688        int depth = ext_depth(inode);
 689        struct ext4_extent *ex;
 690
 691        if (depth != level) {
 692                struct ext4_extent_idx *idx;
 693                idx = path[level].p_idx;
 694                while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 695                        ext_debug("%d: move %d:%llu in new index %llu\n", level,
 696                                        le32_to_cpu(idx->ei_block),
 697                                        ext4_idx_pblock(idx),
 698                                        newblock);
 699                        idx++;
 700                }
 701
 702                return;
 703        }
 704
 705        ex = path[depth].p_ext;
 706        while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 707                ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 708                                le32_to_cpu(ex->ee_block),
 709                                ext4_ext_pblock(ex),
 710                                ext4_ext_is_unwritten(ex),
 711                                ext4_ext_get_actual_len(ex),
 712                                newblock);
 713                ex++;
 714        }
 715}
 716
 717#else
 718#define ext4_ext_show_path(inode, path)
 719#define ext4_ext_show_leaf(inode, path)
 720#define ext4_ext_show_move(inode, path, newblock, level)
 721#endif
 722
 723void ext4_ext_drop_refs(struct ext4_ext_path *path)
 724{
 725        int depth, i;
 726
 727        if (!path)
 728                return;
 729        depth = path->p_depth;
 730        for (i = 0; i <= depth; i++, path++)
 731                if (path->p_bh) {
 732                        brelse(path->p_bh);
 733                        path->p_bh = NULL;
 734                }
 735}
 736
 737/*
 738 * ext4_ext_binsearch_idx:
 739 * binary search for the closest index of the given block
 740 * the header must be checked before calling this
 741 */
 742static void
 743ext4_ext_binsearch_idx(struct inode *inode,
 744                        struct ext4_ext_path *path, ext4_lblk_t block)
 745{
 746        struct ext4_extent_header *eh = path->p_hdr;
 747        struct ext4_extent_idx *r, *l, *m;
 748
 749
 750        ext_debug("binsearch for %u(idx):  ", block);
 751
 752        l = EXT_FIRST_INDEX(eh) + 1;
 753        r = EXT_LAST_INDEX(eh);
 754        while (l <= r) {
 755                m = l + (r - l) / 2;
 756                if (block < le32_to_cpu(m->ei_block))
 757                        r = m - 1;
 758                else
 759                        l = m + 1;
 760                ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 761                                m, le32_to_cpu(m->ei_block),
 762                                r, le32_to_cpu(r->ei_block));
 763        }
 764
 765        path->p_idx = l - 1;
 766        ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 767                  ext4_idx_pblock(path->p_idx));
 768
 769#ifdef CHECK_BINSEARCH
 770        {
 771                struct ext4_extent_idx *chix, *ix;
 772                int k;
 773
 774                chix = ix = EXT_FIRST_INDEX(eh);
 775                for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 776                  if (k != 0 &&
 777                      le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 778                                printk(KERN_DEBUG "k=%d, ix=0x%p, "
 779                                       "first=0x%p\n", k,
 780                                       ix, EXT_FIRST_INDEX(eh));
 781                                printk(KERN_DEBUG "%u <= %u\n",
 782                                       le32_to_cpu(ix->ei_block),
 783                                       le32_to_cpu(ix[-1].ei_block));
 784                        }
 785                        BUG_ON(k && le32_to_cpu(ix->ei_block)
 786                                           <= le32_to_cpu(ix[-1].ei_block));
 787                        if (block < le32_to_cpu(ix->ei_block))
 788                                break;
 789                        chix = ix;
 790                }
 791                BUG_ON(chix != path->p_idx);
 792        }
 793#endif
 794
 795}
 796
 797/*
 798 * ext4_ext_binsearch:
 799 * binary search for closest extent of the given block
 800 * the header must be checked before calling this
 801 */
 802static void
 803ext4_ext_binsearch(struct inode *inode,
 804                struct ext4_ext_path *path, ext4_lblk_t block)
 805{
 806        struct ext4_extent_header *eh = path->p_hdr;
 807        struct ext4_extent *r, *l, *m;
 808
 809        if (eh->eh_entries == 0) {
 810                /*
 811                 * this leaf is empty:
 812                 * we get such a leaf in split/add case
 813                 */
 814                return;
 815        }
 816
 817        ext_debug("binsearch for %u:  ", block);
 818
 819        l = EXT_FIRST_EXTENT(eh) + 1;
 820        r = EXT_LAST_EXTENT(eh);
 821
 822        while (l <= r) {
 823                m = l + (r - l) / 2;
 824                if (block < le32_to_cpu(m->ee_block))
 825                        r = m - 1;
 826                else
 827                        l = m + 1;
 828                ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 829                                m, le32_to_cpu(m->ee_block),
 830                                r, le32_to_cpu(r->ee_block));
 831        }
 832
 833        path->p_ext = l - 1;
 834        ext_debug("  -> %d:%llu:[%d]%d ",
 835                        le32_to_cpu(path->p_ext->ee_block),
 836                        ext4_ext_pblock(path->p_ext),
 837                        ext4_ext_is_unwritten(path->p_ext),
 838                        ext4_ext_get_actual_len(path->p_ext));
 839
 840#ifdef CHECK_BINSEARCH
 841        {
 842                struct ext4_extent *chex, *ex;
 843                int k;
 844
 845                chex = ex = EXT_FIRST_EXTENT(eh);
 846                for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 847                        BUG_ON(k && le32_to_cpu(ex->ee_block)
 848                                          <= le32_to_cpu(ex[-1].ee_block));
 849                        if (block < le32_to_cpu(ex->ee_block))
 850                                break;
 851                        chex = ex;
 852                }
 853                BUG_ON(chex != path->p_ext);
 854        }
 855#endif
 856
 857}
 858
 859int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 860{
 861        struct ext4_extent_header *eh;
 862
 863        eh = ext_inode_hdr(inode);
 864        eh->eh_depth = 0;
 865        eh->eh_entries = 0;
 866        eh->eh_magic = EXT4_EXT_MAGIC;
 867        eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 868        ext4_mark_inode_dirty(handle, inode);
 869        return 0;
 870}
 871
 872struct ext4_ext_path *
 873ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 874                 struct ext4_ext_path **orig_path, int flags)
 875{
 876        struct ext4_extent_header *eh;
 877        struct buffer_head *bh;
 878        struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 879        short int depth, i, ppos = 0;
 880        int ret;
 881
 882        eh = ext_inode_hdr(inode);
 883        depth = ext_depth(inode);
 884
 885        if (path) {
 886                ext4_ext_drop_refs(path);
 887                if (depth > path[0].p_maxdepth) {
 888                        kfree(path);
 889                        *orig_path = path = NULL;
 890                }
 891        }
 892        if (!path) {
 893                /* account possible depth increase */
 894                path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 895                                GFP_NOFS);
 896                if (unlikely(!path))
 897                        return ERR_PTR(-ENOMEM);
 898                path[0].p_maxdepth = depth + 1;
 899        }
 900        path[0].p_hdr = eh;
 901        path[0].p_bh = NULL;
 902
 903        i = depth;
 904        /* walk through the tree */
 905        while (i) {
 906                ext_debug("depth %d: num %d, max %d\n",
 907                          ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 908
 909                ext4_ext_binsearch_idx(inode, path + ppos, block);
 910                path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 911                path[ppos].p_depth = i;
 912                path[ppos].p_ext = NULL;
 913
 914                bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 915                                            flags);
 916                if (IS_ERR(bh)) {
 917                        ret = PTR_ERR(bh);
 918                        goto err;
 919                }
 920
 921                eh = ext_block_hdr(bh);
 922                ppos++;
 923                path[ppos].p_bh = bh;
 924                path[ppos].p_hdr = eh;
 925        }
 926
 927        path[ppos].p_depth = i;
 928        path[ppos].p_ext = NULL;
 929        path[ppos].p_idx = NULL;
 930
 931        /* find extent */
 932        ext4_ext_binsearch(inode, path + ppos, block);
 933        /* if not an empty leaf */
 934        if (path[ppos].p_ext)
 935                path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 936
 937        ext4_ext_show_path(inode, path);
 938
 939        return path;
 940
 941err:
 942        ext4_ext_drop_refs(path);
 943        kfree(path);
 944        if (orig_path)
 945                *orig_path = NULL;
 946        return ERR_PTR(ret);
 947}
 948
 949/*
 950 * ext4_ext_insert_index:
 951 * insert new index [@logical;@ptr] into the block at @curp;
 952 * check where to insert: before @curp or after @curp
 953 */
 954static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 955                                 struct ext4_ext_path *curp,
 956                                 int logical, ext4_fsblk_t ptr)
 957{
 958        struct ext4_extent_idx *ix;
 959        int len, err;
 960
 961        err = ext4_ext_get_access(handle, inode, curp);
 962        if (err)
 963                return err;
 964
 965        if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 966                EXT4_ERROR_INODE(inode,
 967                                 "logical %d == ei_block %d!",
 968                                 logical, le32_to_cpu(curp->p_idx->ei_block));
 969                return -EFSCORRUPTED;
 970        }
 971
 972        if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 973                             >= le16_to_cpu(curp->p_hdr->eh_max))) {
 974                EXT4_ERROR_INODE(inode,
 975                                 "eh_entries %d >= eh_max %d!",
 976                                 le16_to_cpu(curp->p_hdr->eh_entries),
 977                                 le16_to_cpu(curp->p_hdr->eh_max));
 978                return -EFSCORRUPTED;
 979        }
 980
 981        if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 982                /* insert after */
 983                ext_debug("insert new index %d after: %llu\n", logical, ptr);
 984                ix = curp->p_idx + 1;
 985        } else {
 986                /* insert before */
 987                ext_debug("insert new index %d before: %llu\n", logical, ptr);
 988                ix = curp->p_idx;
 989        }
 990
 991        len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 992        BUG_ON(len < 0);
 993        if (len > 0) {
 994                ext_debug("insert new index %d: "
 995                                "move %d indices from 0x%p to 0x%p\n",
 996                                logical, len, ix, ix + 1);
 997                memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 998        }
 999
1000        if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
1001                EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1002                return -EFSCORRUPTED;
1003        }
1004
1005        ix->ei_block = cpu_to_le32(logical);
1006        ext4_idx_store_pblock(ix, ptr);
1007        le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1008
1009        if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1010                EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1011                return -EFSCORRUPTED;
1012        }
1013
1014        err = ext4_ext_dirty(handle, inode, curp);
1015        ext4_std_error(inode->i_sb, err);
1016
1017        return err;
1018}
1019
1020/*
1021 * ext4_ext_split:
1022 * inserts new subtree into the path, using free index entry
1023 * at depth @at:
1024 * - allocates all needed blocks (new leaf and all intermediate index blocks)
1025 * - makes decision where to split
1026 * - moves remaining extents and index entries (right to the split point)
1027 *   into the newly allocated blocks
1028 * - initializes subtree
1029 */
1030static int ext4_ext_split(handle_t *handle, struct inode *inode,
1031                          unsigned int flags,
1032                          struct ext4_ext_path *path,
1033                          struct ext4_extent *newext, int at)
1034{
1035        struct buffer_head *bh = NULL;
1036        int depth = ext_depth(inode);
1037        struct ext4_extent_header *neh;
1038        struct ext4_extent_idx *fidx;
1039        int i = at, k, m, a;
1040        ext4_fsblk_t newblock, oldblock;
1041        __le32 border;
1042        ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1043        int err = 0;
1044
1045        /* make decision: where to split? */
1046        /* FIXME: now decision is simplest: at current extent */
1047
1048        /* if current leaf will be split, then we should use
1049         * border from split point */
1050        if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1051                EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1052                return -EFSCORRUPTED;
1053        }
1054        if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1055                border = path[depth].p_ext[1].ee_block;
1056                ext_debug("leaf will be split."
1057                                " next leaf starts at %d\n",
1058                                  le32_to_cpu(border));
1059        } else {
1060                border = newext->ee_block;
1061                ext_debug("leaf will be added."
1062                                " next leaf starts at %d\n",
1063                                le32_to_cpu(border));
1064        }
1065
1066        /*
1067         * If error occurs, then we break processing
1068         * and mark filesystem read-only. index won't
1069         * be inserted and tree will be in consistent
1070         * state. Next mount will repair buffers too.
1071         */
1072
1073        /*
1074         * Get array to track all allocated blocks.
1075         * We need this to handle errors and free blocks
1076         * upon them.
1077         */
1078        ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1079        if (!ablocks)
1080                return -ENOMEM;
1081
1082        /* allocate all needed blocks */
1083        ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1084        for (a = 0; a < depth - at; a++) {
1085                newblock = ext4_ext_new_meta_block(handle, inode, path,
1086                                                   newext, &err, flags);
1087                if (newblock == 0)
1088                        goto cleanup;
1089                ablocks[a] = newblock;
1090        }
1091
1092        /* initialize new leaf */
1093        newblock = ablocks[--a];
1094        if (unlikely(newblock == 0)) {
1095                EXT4_ERROR_INODE(inode, "newblock == 0!");
1096                err = -EFSCORRUPTED;
1097                goto cleanup;
1098        }
1099        bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1100        if (unlikely(!bh)) {
1101                err = -ENOMEM;
1102                goto cleanup;
1103        }
1104        lock_buffer(bh);
1105
1106        err = ext4_journal_get_create_access(handle, bh);
1107        if (err)
1108                goto cleanup;
1109
1110        neh = ext_block_hdr(bh);
1111        neh->eh_entries = 0;
1112        neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1113        neh->eh_magic = EXT4_EXT_MAGIC;
1114        neh->eh_depth = 0;
1115
1116        /* move remainder of path[depth] to the new leaf */
1117        if (unlikely(path[depth].p_hdr->eh_entries !=
1118                     path[depth].p_hdr->eh_max)) {
1119                EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1120                                 path[depth].p_hdr->eh_entries,
1121                                 path[depth].p_hdr->eh_max);
1122                err = -EFSCORRUPTED;
1123                goto cleanup;
1124        }
1125        /* start copy from next extent */
1126        m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1127        ext4_ext_show_move(inode, path, newblock, depth);
1128        if (m) {
1129                struct ext4_extent *ex;
1130                ex = EXT_FIRST_EXTENT(neh);
1131                memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1132                le16_add_cpu(&neh->eh_entries, m);
1133        }
1134
1135        ext4_extent_block_csum_set(inode, neh);
1136        set_buffer_uptodate(bh);
1137        unlock_buffer(bh);
1138
1139        err = ext4_handle_dirty_metadata(handle, inode, bh);
1140        if (err)
1141                goto cleanup;
1142        brelse(bh);
1143        bh = NULL;
1144
1145        /* correct old leaf */
1146        if (m) {
1147                err = ext4_ext_get_access(handle, inode, path + depth);
1148                if (err)
1149                        goto cleanup;
1150                le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1151                err = ext4_ext_dirty(handle, inode, path + depth);
1152                if (err)
1153                        goto cleanup;
1154
1155        }
1156
1157        /* create intermediate indexes */
1158        k = depth - at - 1;
1159        if (unlikely(k < 0)) {
1160                EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1161                err = -EFSCORRUPTED;
1162                goto cleanup;
1163        }
1164        if (k)
1165                ext_debug("create %d intermediate indices\n", k);
1166        /* insert new index into current index block */
1167        /* current depth stored in i var */
1168        i = depth - 1;
1169        while (k--) {
1170                oldblock = newblock;
1171                newblock = ablocks[--a];
1172                bh = sb_getblk(inode->i_sb, newblock);
1173                if (unlikely(!bh)) {
1174                        err = -ENOMEM;
1175                        goto cleanup;
1176                }
1177                lock_buffer(bh);
1178
1179                err = ext4_journal_get_create_access(handle, bh);
1180                if (err)
1181                        goto cleanup;
1182
1183                neh = ext_block_hdr(bh);
1184                neh->eh_entries = cpu_to_le16(1);
1185                neh->eh_magic = EXT4_EXT_MAGIC;
1186                neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1187                neh->eh_depth = cpu_to_le16(depth - i);
1188                fidx = EXT_FIRST_INDEX(neh);
1189                fidx->ei_block = border;
1190                ext4_idx_store_pblock(fidx, oldblock);
1191
1192                ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1193                                i, newblock, le32_to_cpu(border), oldblock);
1194
1195                /* move remainder of path[i] to the new index block */
1196                if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1197                                        EXT_LAST_INDEX(path[i].p_hdr))) {
1198                        EXT4_ERROR_INODE(inode,
1199                                         "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1200                                         le32_to_cpu(path[i].p_ext->ee_block));
1201                        err = -EFSCORRUPTED;
1202                        goto cleanup;
1203                }
1204                /* start copy indexes */
1205                m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1206                ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1207                                EXT_MAX_INDEX(path[i].p_hdr));
1208                ext4_ext_show_move(inode, path, newblock, i);
1209                if (m) {
1210                        memmove(++fidx, path[i].p_idx,
1211                                sizeof(struct ext4_extent_idx) * m);
1212                        le16_add_cpu(&neh->eh_entries, m);
1213                }
1214                ext4_extent_block_csum_set(inode, neh);
1215                set_buffer_uptodate(bh);
1216                unlock_buffer(bh);
1217
1218                err = ext4_handle_dirty_metadata(handle, inode, bh);
1219                if (err)
1220                        goto cleanup;
1221                brelse(bh);
1222                bh = NULL;
1223
1224                /* correct old index */
1225                if (m) {
1226                        err = ext4_ext_get_access(handle, inode, path + i);
1227                        if (err)
1228                                goto cleanup;
1229                        le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1230                        err = ext4_ext_dirty(handle, inode, path + i);
1231                        if (err)
1232                                goto cleanup;
1233                }
1234
1235                i--;
1236        }
1237
1238        /* insert new index */
1239        err = ext4_ext_insert_index(handle, inode, path + at,
1240                                    le32_to_cpu(border), newblock);
1241
1242cleanup:
1243        if (bh) {
1244                if (buffer_locked(bh))
1245                        unlock_buffer(bh);
1246                brelse(bh);
1247        }
1248
1249        if (err) {
1250                /* free all allocated blocks in error case */
1251                for (i = 0; i < depth; i++) {
1252                        if (!ablocks[i])
1253                                continue;
1254                        ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1255                                         EXT4_FREE_BLOCKS_METADATA);
1256                }
1257        }
1258        kfree(ablocks);
1259
1260        return err;
1261}
1262
1263/*
1264 * ext4_ext_grow_indepth:
1265 * implements tree growing procedure:
1266 * - allocates new block
1267 * - moves top-level data (index block or leaf) into the new block
1268 * - initializes new top-level, creating index that points to the
1269 *   just created block
1270 */
1271static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1272                                 unsigned int flags)
1273{
1274        struct ext4_extent_header *neh;
1275        struct buffer_head *bh;
1276        ext4_fsblk_t newblock, goal = 0;
1277        struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1278        int err = 0;
1279
1280        /* Try to prepend new index to old one */
1281        if (ext_depth(inode))
1282                goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1283        if (goal > le32_to_cpu(es->s_first_data_block)) {
1284                flags |= EXT4_MB_HINT_TRY_GOAL;
1285                goal--;
1286        } else
1287                goal = ext4_inode_to_goal_block(inode);
1288        newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1289                                        NULL, &err);
1290        if (newblock == 0)
1291                return err;
1292
1293        bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1294        if (unlikely(!bh))
1295                return -ENOMEM;
1296        lock_buffer(bh);
1297
1298        err = ext4_journal_get_create_access(handle, bh);
1299        if (err) {
1300                unlock_buffer(bh);
1301                goto out;
1302        }
1303
1304        /* move top-level index/leaf into new block */
1305        memmove(bh->b_data, EXT4_I(inode)->i_data,
1306                sizeof(EXT4_I(inode)->i_data));
1307
1308        /* set size of new block */
1309        neh = ext_block_hdr(bh);
1310        /* old root could have indexes or leaves
1311         * so calculate e_max right way */
1312        if (ext_depth(inode))
1313                neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1314        else
1315                neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1316        neh->eh_magic = EXT4_EXT_MAGIC;
1317        ext4_extent_block_csum_set(inode, neh);
1318        set_buffer_uptodate(bh);
1319        unlock_buffer(bh);
1320
1321        err = ext4_handle_dirty_metadata(handle, inode, bh);
1322        if (err)
1323                goto out;
1324
1325        /* Update top-level index: num,max,pointer */
1326        neh = ext_inode_hdr(inode);
1327        neh->eh_entries = cpu_to_le16(1);
1328        ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1329        if (neh->eh_depth == 0) {
1330                /* Root extent block becomes index block */
1331                neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1332                EXT_FIRST_INDEX(neh)->ei_block =
1333                        EXT_FIRST_EXTENT(neh)->ee_block;
1334        }
1335        ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1336                  le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1337                  le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1338                  ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1339
1340        le16_add_cpu(&neh->eh_depth, 1);
1341        ext4_mark_inode_dirty(handle, inode);
1342out:
1343        brelse(bh);
1344
1345        return err;
1346}
1347
1348/*
1349 * ext4_ext_create_new_leaf:
1350 * finds empty index and adds new leaf.
1351 * if no free index is found, then it requests in-depth growing.
1352 */
1353static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1354                                    unsigned int mb_flags,
1355                                    unsigned int gb_flags,
1356                                    struct ext4_ext_path **ppath,
1357                                    struct ext4_extent *newext)
1358{
1359        struct ext4_ext_path *path = *ppath;
1360        struct ext4_ext_path *curp;
1361        int depth, i, err = 0;
1362
1363repeat:
1364        i = depth = ext_depth(inode);
1365
1366        /* walk up to the tree and look for free index entry */
1367        curp = path + depth;
1368        while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1369                i--;
1370                curp--;
1371        }
1372
1373        /* we use already allocated block for index block,
1374         * so subsequent data blocks should be contiguous */
1375        if (EXT_HAS_FREE_INDEX(curp)) {
1376                /* if we found index with free entry, then use that
1377                 * entry: create all needed subtree and add new leaf */
1378                err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1379                if (err)
1380                        goto out;
1381
1382                /* refill path */
1383                path = ext4_find_extent(inode,
1384                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1385                                    ppath, gb_flags);
1386                if (IS_ERR(path))
1387                        err = PTR_ERR(path);
1388        } else {
1389                /* tree is full, time to grow in depth */
1390                err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1391                if (err)
1392                        goto out;
1393
1394                /* refill path */
1395                path = ext4_find_extent(inode,
1396                                   (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1397                                    ppath, gb_flags);
1398                if (IS_ERR(path)) {
1399                        err = PTR_ERR(path);
1400                        goto out;
1401                }
1402
1403                /*
1404                 * only first (depth 0 -> 1) produces free space;
1405                 * in all other cases we have to split the grown tree
1406                 */
1407                depth = ext_depth(inode);
1408                if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1409                        /* now we need to split */
1410                        goto repeat;
1411                }
1412        }
1413
1414out:
1415        return err;
1416}
1417
1418/*
1419 * search the closest allocated block to the left for *logical
1420 * and returns it at @logical + it's physical address at @phys
1421 * if *logical is the smallest allocated block, the function
1422 * returns 0 at @phys
1423 * return value contains 0 (success) or error code
1424 */
1425static int ext4_ext_search_left(struct inode *inode,
1426                                struct ext4_ext_path *path,
1427                                ext4_lblk_t *logical, ext4_fsblk_t *phys)
1428{
1429        struct ext4_extent_idx *ix;
1430        struct ext4_extent *ex;
1431        int depth, ee_len;
1432
1433        if (unlikely(path == NULL)) {
1434                EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1435                return -EFSCORRUPTED;
1436        }
1437        depth = path->p_depth;
1438        *phys = 0;
1439
1440        if (depth == 0 && path->p_ext == NULL)
1441                return 0;
1442
1443        /* usually extent in the path covers blocks smaller
1444         * then *logical, but it can be that extent is the
1445         * first one in the file */
1446
1447        ex = path[depth].p_ext;
1448        ee_len = ext4_ext_get_actual_len(ex);
1449        if (*logical < le32_to_cpu(ex->ee_block)) {
1450                if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1451                        EXT4_ERROR_INODE(inode,
1452                                         "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1453                                         *logical, le32_to_cpu(ex->ee_block));
1454                        return -EFSCORRUPTED;
1455                }
1456                while (--depth >= 0) {
1457                        ix = path[depth].p_idx;
1458                        if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1459                                EXT4_ERROR_INODE(inode,
1460                                  "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1461                                  ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1462                                  EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1463                le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1464                                  depth);
1465                                return -EFSCORRUPTED;
1466                        }
1467                }
1468                return 0;
1469        }
1470
1471        if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1472                EXT4_ERROR_INODE(inode,
1473                                 "logical %d < ee_block %d + ee_len %d!",
1474                                 *logical, le32_to_cpu(ex->ee_block), ee_len);
1475                return -EFSCORRUPTED;
1476        }
1477
1478        *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1479        *phys = ext4_ext_pblock(ex) + ee_len - 1;
1480        return 0;
1481}
1482
1483/*
1484 * search the closest allocated block to the right for *logical
1485 * and returns it at @logical + it's physical address at @phys
1486 * if *logical is the largest allocated block, the function
1487 * returns 0 at @phys
1488 * return value contains 0 (success) or error code
1489 */
1490static int ext4_ext_search_right(struct inode *inode,
1491                                 struct ext4_ext_path *path,
1492                                 ext4_lblk_t *logical, ext4_fsblk_t *phys,
1493                                 struct ext4_extent **ret_ex)
1494{
1495        struct buffer_head *bh = NULL;
1496        struct ext4_extent_header *eh;
1497        struct ext4_extent_idx *ix;
1498        struct ext4_extent *ex;
1499        ext4_fsblk_t block;
1500        int depth;      /* Note, NOT eh_depth; depth from top of tree */
1501        int ee_len;
1502
1503        if (unlikely(path == NULL)) {
1504                EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1505                return -EFSCORRUPTED;
1506        }
1507        depth = path->p_depth;
1508        *phys = 0;
1509
1510        if (depth == 0 && path->p_ext == NULL)
1511                return 0;
1512
1513        /* usually extent in the path covers blocks smaller
1514         * then *logical, but it can be that extent is the
1515         * first one in the file */
1516
1517        ex = path[depth].p_ext;
1518        ee_len = ext4_ext_get_actual_len(ex);
1519        if (*logical < le32_to_cpu(ex->ee_block)) {
1520                if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1521                        EXT4_ERROR_INODE(inode,
1522                                         "first_extent(path[%d].p_hdr) != ex",
1523                                         depth);
1524                        return -EFSCORRUPTED;
1525                }
1526                while (--depth >= 0) {
1527                        ix = path[depth].p_idx;
1528                        if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1529                                EXT4_ERROR_INODE(inode,
1530                                                 "ix != EXT_FIRST_INDEX *logical %d!",
1531                                                 *logical);
1532                                return -EFSCORRUPTED;
1533                        }
1534                }
1535                goto found_extent;
1536        }
1537
1538        if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1539                EXT4_ERROR_INODE(inode,
1540                                 "logical %d < ee_block %d + ee_len %d!",
1541                                 *logical, le32_to_cpu(ex->ee_block), ee_len);
1542                return -EFSCORRUPTED;
1543        }
1544
1545        if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1546                /* next allocated block in this leaf */
1547                ex++;
1548                goto found_extent;
1549        }
1550
1551        /* go up and search for index to the right */
1552        while (--depth >= 0) {
1553                ix = path[depth].p_idx;
1554                if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1555                        goto got_index;
1556        }
1557
1558        /* we've gone up to the root and found no index to the right */
1559        return 0;
1560
1561got_index:
1562        /* we've found index to the right, let's
1563         * follow it and find the closest allocated
1564         * block to the right */
1565        ix++;
1566        block = ext4_idx_pblock(ix);
1567        while (++depth < path->p_depth) {
1568                /* subtract from p_depth to get proper eh_depth */
1569                bh = read_extent_tree_block(inode, block,
1570                                            path->p_depth - depth, 0);
1571                if (IS_ERR(bh))
1572                        return PTR_ERR(bh);
1573                eh = ext_block_hdr(bh);
1574                ix = EXT_FIRST_INDEX(eh);
1575                block = ext4_idx_pblock(ix);
1576                put_bh(bh);
1577        }
1578
1579        bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1580        if (IS_ERR(bh))
1581                return PTR_ERR(bh);
1582        eh = ext_block_hdr(bh);
1583        ex = EXT_FIRST_EXTENT(eh);
1584found_extent:
1585        *logical = le32_to_cpu(ex->ee_block);
1586        *phys = ext4_ext_pblock(ex);
1587        *ret_ex = ex;
1588        if (bh)
1589                put_bh(bh);
1590        return 0;
1591}
1592
1593/*
1594 * ext4_ext_next_allocated_block:
1595 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1596 * NOTE: it considers block number from index entry as
1597 * allocated block. Thus, index entries have to be consistent
1598 * with leaves.
1599 */
1600ext4_lblk_t
1601ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1602{
1603        int depth;
1604
1605        BUG_ON(path == NULL);
1606        depth = path->p_depth;
1607
1608        if (depth == 0 && path->p_ext == NULL)
1609                return EXT_MAX_BLOCKS;
1610
1611        while (depth >= 0) {
1612                if (depth == path->p_depth) {
1613                        /* leaf */
1614                        if (path[depth].p_ext &&
1615                                path[depth].p_ext !=
1616                                        EXT_LAST_EXTENT(path[depth].p_hdr))
1617                          return le32_to_cpu(path[depth].p_ext[1].ee_block);
1618                } else {
1619                        /* index */
1620                        if (path[depth].p_idx !=
1621                                        EXT_LAST_INDEX(path[depth].p_hdr))
1622                          return le32_to_cpu(path[depth].p_idx[1].ei_block);
1623                }
1624                depth--;
1625        }
1626
1627        return EXT_MAX_BLOCKS;
1628}
1629
1630/*
1631 * ext4_ext_next_leaf_block:
1632 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1633 */
1634static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1635{
1636        int depth;
1637
1638        BUG_ON(path == NULL);
1639        depth = path->p_depth;
1640
1641        /* zero-tree has no leaf blocks at all */
1642        if (depth == 0)
1643                return EXT_MAX_BLOCKS;
1644
1645        /* go to index block */
1646        depth--;
1647
1648        while (depth >= 0) {
1649                if (path[depth].p_idx !=
1650                                EXT_LAST_INDEX(path[depth].p_hdr))
1651                        return (ext4_lblk_t)
1652                                le32_to_cpu(path[depth].p_idx[1].ei_block);
1653                depth--;
1654        }
1655
1656        return EXT_MAX_BLOCKS;
1657}
1658
1659/*
1660 * ext4_ext_correct_indexes:
1661 * if leaf gets modified and modified extent is first in the leaf,
1662 * then we have to correct all indexes above.
1663 * TODO: do we need to correct tree in all cases?
1664 */
1665static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1666                                struct ext4_ext_path *path)
1667{
1668        struct ext4_extent_header *eh;
1669        int depth = ext_depth(inode);
1670        struct ext4_extent *ex;
1671        __le32 border;
1672        int k, err = 0;
1673
1674        eh = path[depth].p_hdr;
1675        ex = path[depth].p_ext;
1676
1677        if (unlikely(ex == NULL || eh == NULL)) {
1678                EXT4_ERROR_INODE(inode,
1679                                 "ex %p == NULL or eh %p == NULL", ex, eh);
1680                return -EFSCORRUPTED;
1681        }
1682
1683        if (depth == 0) {
1684                /* there is no tree at all */
1685                return 0;
1686        }
1687
1688        if (ex != EXT_FIRST_EXTENT(eh)) {
1689                /* we correct tree if first leaf got modified only */
1690                return 0;
1691        }
1692
1693        /*
1694         * TODO: we need correction if border is smaller than current one
1695         */
1696        k = depth - 1;
1697        border = path[depth].p_ext->ee_block;
1698        err = ext4_ext_get_access(handle, inode, path + k);
1699        if (err)
1700                return err;
1701        path[k].p_idx->ei_block = border;
1702        err = ext4_ext_dirty(handle, inode, path + k);
1703        if (err)
1704                return err;
1705
1706        while (k--) {
1707                /* change all left-side indexes */
1708                if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1709                        break;
1710                err = ext4_ext_get_access(handle, inode, path + k);
1711                if (err)
1712                        break;
1713                path[k].p_idx->ei_block = border;
1714                err = ext4_ext_dirty(handle, inode, path + k);
1715                if (err)
1716                        break;
1717        }
1718
1719        return err;
1720}
1721
1722int
1723ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1724                                struct ext4_extent *ex2)
1725{
1726        unsigned short ext1_ee_len, ext2_ee_len;
1727
1728        if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1729                return 0;
1730
1731        ext1_ee_len = ext4_ext_get_actual_len(ex1);
1732        ext2_ee_len = ext4_ext_get_actual_len(ex2);
1733
1734        if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1735                        le32_to_cpu(ex2->ee_block))
1736                return 0;
1737
1738        /*
1739         * To allow future support for preallocated extents to be added
1740         * as an RO_COMPAT feature, refuse to merge to extents if
1741         * this can result in the top bit of ee_len being set.
1742         */
1743        if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1744                return 0;
1745        /*
1746         * The check for IO to unwritten extent is somewhat racy as we
1747         * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after
1748         * dropping i_data_sem. But reserved blocks should save us in that
1749         * case.
1750         */
1751        if (ext4_ext_is_unwritten(ex1) &&
1752            (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1753             atomic_read(&EXT4_I(inode)->i_unwritten) ||
1754             (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1755                return 0;
1756#ifdef AGGRESSIVE_TEST
1757        if (ext1_ee_len >= 4)
1758                return 0;
1759#endif
1760
1761        if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1762                return 1;
1763        return 0;
1764}
1765
1766/*
1767 * This function tries to merge the "ex" extent to the next extent in the tree.
1768 * It always tries to merge towards right. If you want to merge towards
1769 * left, pass "ex - 1" as argument instead of "ex".
1770 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1771 * 1 if they got merged.
1772 */
1773static int ext4_ext_try_to_merge_right(struct inode *inode,
1774                                 struct ext4_ext_path *path,
1775                                 struct ext4_extent *ex)
1776{
1777        struct ext4_extent_header *eh;
1778        unsigned int depth, len;
1779        int merge_done = 0, unwritten;
1780
1781        depth = ext_depth(inode);
1782        BUG_ON(path[depth].p_hdr == NULL);
1783        eh = path[depth].p_hdr;
1784
1785        while (ex < EXT_LAST_EXTENT(eh)) {
1786                if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1787                        break;
1788                /* merge with next extent! */
1789                unwritten = ext4_ext_is_unwritten(ex);
1790                ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1791                                + ext4_ext_get_actual_len(ex + 1));
1792                if (unwritten)
1793                        ext4_ext_mark_unwritten(ex);
1794
1795                if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1796                        len = (EXT_LAST_EXTENT(eh) - ex - 1)
1797                                * sizeof(struct ext4_extent);
1798                        memmove(ex + 1, ex + 2, len);
1799                }
1800                le16_add_cpu(&eh->eh_entries, -1);
1801                merge_done = 1;
1802                WARN_ON(eh->eh_entries == 0);
1803                if (!eh->eh_entries)
1804                        EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1805        }
1806
1807        return merge_done;
1808}
1809
1810/*
1811 * This function does a very simple check to see if we can collapse
1812 * an extent tree with a single extent tree leaf block into the inode.
1813 */
1814static void ext4_ext_try_to_merge_up(handle_t *handle,
1815                                     struct inode *inode,
1816                                     struct ext4_ext_path *path)
1817{
1818        size_t s;
1819        unsigned max_root = ext4_ext_space_root(inode, 0);
1820        ext4_fsblk_t blk;
1821
1822        if ((path[0].p_depth != 1) ||
1823            (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1824            (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1825                return;
1826
1827        /*
1828         * We need to modify the block allocation bitmap and the block
1829         * group descriptor to release the extent tree block.  If we
1830         * can't get the journal credits, give up.
1831         */
1832        if (ext4_journal_extend(handle, 2))
1833                return;
1834
1835        /*
1836         * Copy the extent data up to the inode
1837         */
1838        blk = ext4_idx_pblock(path[0].p_idx);
1839        s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1840                sizeof(struct ext4_extent_idx);
1841        s += sizeof(struct ext4_extent_header);
1842
1843        path[1].p_maxdepth = path[0].p_maxdepth;
1844        memcpy(path[0].p_hdr, path[1].p_hdr, s);
1845        path[0].p_depth = 0;
1846        path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1847                (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1848        path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1849
1850        brelse(path[1].p_bh);
1851        ext4_free_blocks(handle, inode, NULL, blk, 1,
1852                         EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1853}
1854
1855/*
1856 * This function tries to merge the @ex extent to neighbours in the tree.
1857 * return 1 if merge left else 0.
1858 */
1859static void ext4_ext_try_to_merge(handle_t *handle,
1860                                  struct inode *inode,
1861                                  struct ext4_ext_path *path,
1862                                  struct ext4_extent *ex) {
1863        struct ext4_extent_header *eh;
1864        unsigned int depth;
1865        int merge_done = 0;
1866
1867        depth = ext_depth(inode);
1868        BUG_ON(path[depth].p_hdr == NULL);
1869        eh = path[depth].p_hdr;
1870
1871        if (ex > EXT_FIRST_EXTENT(eh))
1872                merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1873
1874        if (!merge_done)
1875                (void) ext4_ext_try_to_merge_right(inode, path, ex);
1876
1877        ext4_ext_try_to_merge_up(handle, inode, path);
1878}
1879
1880/*
1881 * check if a portion of the "newext" extent overlaps with an
1882 * existing extent.
1883 *
1884 * If there is an overlap discovered, it updates the length of the newext
1885 * such that there will be no overlap, and then returns 1.
1886 * If there is no overlap found, it returns 0.
1887 */
1888static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1889                                           struct inode *inode,
1890                                           struct ext4_extent *newext,
1891                                           struct ext4_ext_path *path)
1892{
1893        ext4_lblk_t b1, b2;
1894        unsigned int depth, len1;
1895        unsigned int ret = 0;
1896
1897        b1 = le32_to_cpu(newext->ee_block);
1898        len1 = ext4_ext_get_actual_len(newext);
1899        depth = ext_depth(inode);
1900        if (!path[depth].p_ext)
1901                goto out;
1902        b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1903
1904        /*
1905         * get the next allocated block if the extent in the path
1906         * is before the requested block(s)
1907         */
1908        if (b2 < b1) {
1909                b2 = ext4_ext_next_allocated_block(path);
1910                if (b2 == EXT_MAX_BLOCKS)
1911                        goto out;
1912                b2 = EXT4_LBLK_CMASK(sbi, b2);
1913        }
1914
1915        /* check for wrap through zero on extent logical start block*/
1916        if (b1 + len1 < b1) {
1917                len1 = EXT_MAX_BLOCKS - b1;
1918                newext->ee_len = cpu_to_le16(len1);
1919                ret = 1;
1920        }
1921
1922        /* check for overlap */
1923        if (b1 + len1 > b2) {
1924                newext->ee_len = cpu_to_le16(b2 - b1);
1925                ret = 1;
1926        }
1927out:
1928        return ret;
1929}
1930
1931/*
1932 * ext4_ext_insert_extent:
1933 * tries to merge requsted extent into the existing extent or
1934 * inserts requested extent as new one into the tree,
1935 * creating new leaf in the no-space case.
1936 */
1937int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1938                                struct ext4_ext_path **ppath,
1939                                struct ext4_extent *newext, int gb_flags)
1940{
1941        struct ext4_ext_path *path = *ppath;
1942        struct ext4_extent_header *eh;
1943        struct ext4_extent *ex, *fex;
1944        struct ext4_extent *nearex; /* nearest extent */
1945        struct ext4_ext_path *npath = NULL;
1946        int depth, len, err;
1947        ext4_lblk_t next;
1948        int mb_flags = 0, unwritten;
1949
1950        if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1951                mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1952        if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1953                EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1954                return -EFSCORRUPTED;
1955        }
1956        depth = ext_depth(inode);
1957        ex = path[depth].p_ext;
1958        eh = path[depth].p_hdr;
1959        if (unlikely(path[depth].p_hdr == NULL)) {
1960                EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1961                return -EFSCORRUPTED;
1962        }
1963
1964        /* try to insert block into found extent and return */
1965        if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1966
1967                /*
1968                 * Try to see whether we should rather test the extent on
1969                 * right from ex, or from the left of ex. This is because
1970                 * ext4_find_extent() can return either extent on the
1971                 * left, or on the right from the searched position. This
1972                 * will make merging more effective.
1973                 */
1974                if (ex < EXT_LAST_EXTENT(eh) &&
1975                    (le32_to_cpu(ex->ee_block) +
1976                    ext4_ext_get_actual_len(ex) <
1977                    le32_to_cpu(newext->ee_block))) {
1978                        ex += 1;
1979                        goto prepend;
1980                } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1981                           (le32_to_cpu(newext->ee_block) +
1982                           ext4_ext_get_actual_len(newext) <
1983                           le32_to_cpu(ex->ee_block)))
1984                        ex -= 1;
1985
1986                /* Try to append newex to the ex */
1987                if (ext4_can_extents_be_merged(inode, ex, newext)) {
1988                        ext_debug("append [%d]%d block to %u:[%d]%d"
1989                                  "(from %llu)\n",
1990                                  ext4_ext_is_unwritten(newext),
1991                                  ext4_ext_get_actual_len(newext),
1992                                  le32_to_cpu(ex->ee_block),
1993                                  ext4_ext_is_unwritten(ex),
1994                                  ext4_ext_get_actual_len(ex),
1995                                  ext4_ext_pblock(ex));
1996                        err = ext4_ext_get_access(handle, inode,
1997                                                  path + depth);
1998                        if (err)
1999                                return err;
2000                        unwritten = ext4_ext_is_unwritten(ex);
2001                        ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2002                                        + ext4_ext_get_actual_len(newext));
2003                        if (unwritten)
2004                                ext4_ext_mark_unwritten(ex);
2005                        eh = path[depth].p_hdr;
2006                        nearex = ex;
2007                        goto merge;
2008                }
2009
2010prepend:
2011                /* Try to prepend newex to the ex */
2012                if (ext4_can_extents_be_merged(inode, newext, ex)) {
2013                        ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2014                                  "(from %llu)\n",
2015                                  le32_to_cpu(newext->ee_block),
2016                                  ext4_ext_is_unwritten(newext),
2017                                  ext4_ext_get_actual_len(newext),
2018                                  le32_to_cpu(ex->ee_block),
2019                                  ext4_ext_is_unwritten(ex),
2020                                  ext4_ext_get_actual_len(ex),
2021                                  ext4_ext_pblock(ex));
2022                        err = ext4_ext_get_access(handle, inode,
2023                                                  path + depth);
2024                        if (err)
2025                                return err;
2026
2027                        unwritten = ext4_ext_is_unwritten(ex);
2028                        ex->ee_block = newext->ee_block;
2029                        ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2030                        ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2031                                        + ext4_ext_get_actual_len(newext));
2032                        if (unwritten)
2033                                ext4_ext_mark_unwritten(ex);
2034                        eh = path[depth].p_hdr;
2035                        nearex = ex;
2036                        goto merge;
2037                }
2038        }
2039
2040        depth = ext_depth(inode);
2041        eh = path[depth].p_hdr;
2042        if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2043                goto has_space;
2044
2045        /* probably next leaf has space for us? */
2046        fex = EXT_LAST_EXTENT(eh);
2047        next = EXT_MAX_BLOCKS;
2048        if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2049                next = ext4_ext_next_leaf_block(path);
2050        if (next != EXT_MAX_BLOCKS) {
2051                ext_debug("next leaf block - %u\n", next);
2052                BUG_ON(npath != NULL);
2053                npath = ext4_find_extent(inode, next, NULL, 0);
2054                if (IS_ERR(npath))
2055                        return PTR_ERR(npath);
2056                BUG_ON(npath->p_depth != path->p_depth);
2057                eh = npath[depth].p_hdr;
2058                if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2059                        ext_debug("next leaf isn't full(%d)\n",
2060                                  le16_to_cpu(eh->eh_entries));
2061                        path = npath;
2062                        goto has_space;
2063                }
2064                ext_debug("next leaf has no free space(%d,%d)\n",
2065                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2066        }
2067
2068        /*
2069         * There is no free space in the found leaf.
2070         * We're gonna add a new leaf in the tree.
2071         */
2072        if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2073                mb_flags |= EXT4_MB_USE_RESERVED;
2074        err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2075                                       ppath, newext);
2076        if (err)
2077                goto cleanup;
2078        depth = ext_depth(inode);
2079        eh = path[depth].p_hdr;
2080
2081has_space:
2082        nearex = path[depth].p_ext;
2083
2084        err = ext4_ext_get_access(handle, inode, path + depth);
2085        if (err)
2086                goto cleanup;
2087
2088        if (!nearex) {
2089                /* there is no extent in this leaf, create first one */
2090                ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2091                                le32_to_cpu(newext->ee_block),
2092                                ext4_ext_pblock(newext),
2093                                ext4_ext_is_unwritten(newext),
2094                                ext4_ext_get_actual_len(newext));
2095                nearex = EXT_FIRST_EXTENT(eh);
2096        } else {
2097                if (le32_to_cpu(newext->ee_block)
2098                           > le32_to_cpu(nearex->ee_block)) {
2099                        /* Insert after */
2100                        ext_debug("insert %u:%llu:[%d]%d before: "
2101                                        "nearest %p\n",
2102                                        le32_to_cpu(newext->ee_block),
2103                                        ext4_ext_pblock(newext),
2104                                        ext4_ext_is_unwritten(newext),
2105                                        ext4_ext_get_actual_len(newext),
2106                                        nearex);
2107                        nearex++;
2108                } else {
2109                        /* Insert before */
2110                        BUG_ON(newext->ee_block == nearex->ee_block);
2111                        ext_debug("insert %u:%llu:[%d]%d after: "
2112                                        "nearest %p\n",
2113                                        le32_to_cpu(newext->ee_block),
2114                                        ext4_ext_pblock(newext),
2115                                        ext4_ext_is_unwritten(newext),
2116                                        ext4_ext_get_actual_len(newext),
2117                                        nearex);
2118                }
2119                len = EXT_LAST_EXTENT(eh) - nearex + 1;
2120                if (len > 0) {
2121                        ext_debug("insert %u:%llu:[%d]%d: "
2122                                        "move %d extents from 0x%p to 0x%p\n",
2123                                        le32_to_cpu(newext->ee_block),
2124                                        ext4_ext_pblock(newext),
2125                                        ext4_ext_is_unwritten(newext),
2126                                        ext4_ext_get_actual_len(newext),
2127                                        len, nearex, nearex + 1);
2128                        memmove(nearex + 1, nearex,
2129                                len * sizeof(struct ext4_extent));
2130                }
2131        }
2132
2133        le16_add_cpu(&eh->eh_entries, 1);
2134        path[depth].p_ext = nearex;
2135        nearex->ee_block = newext->ee_block;
2136        ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2137        nearex->ee_len = newext->ee_len;
2138
2139merge:
2140        /* try to merge extents */
2141        if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2142                ext4_ext_try_to_merge(handle, inode, path, nearex);
2143
2144
2145        /* time to correct all indexes above */
2146        err = ext4_ext_correct_indexes(handle, inode, path);
2147        if (err)
2148                goto cleanup;
2149
2150        err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2151
2152cleanup:
2153        ext4_ext_drop_refs(npath);
2154        kfree(npath);
2155        return err;
2156}
2157
2158static int ext4_fill_fiemap_extents(struct inode *inode,
2159                                    ext4_lblk_t block, ext4_lblk_t num,
2160                                    struct fiemap_extent_info *fieinfo)
2161{
2162        struct ext4_ext_path *path = NULL;
2163        struct ext4_extent *ex;
2164        struct extent_status es;
2165        ext4_lblk_t next, next_del, start = 0, end = 0;
2166        ext4_lblk_t last = block + num;
2167        int exists, depth = 0, err = 0;
2168        unsigned int flags = 0;
2169        unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2170
2171        while (block < last && block != EXT_MAX_BLOCKS) {
2172                num = last - block;
2173                /* find extent for this block */
2174                down_read(&EXT4_I(inode)->i_data_sem);
2175
2176                path = ext4_find_extent(inode, block, &path, 0);
2177                if (IS_ERR(path)) {
2178                        up_read(&EXT4_I(inode)->i_data_sem);
2179                        err = PTR_ERR(path);
2180                        path = NULL;
2181                        break;
2182                }
2183
2184                depth = ext_depth(inode);
2185                if (unlikely(path[depth].p_hdr == NULL)) {
2186                        up_read(&EXT4_I(inode)->i_data_sem);
2187                        EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2188                        err = -EFSCORRUPTED;
2189                        break;
2190                }
2191                ex = path[depth].p_ext;
2192                next = ext4_ext_next_allocated_block(path);
2193
2194                flags = 0;
2195                exists = 0;
2196                if (!ex) {
2197                        /* there is no extent yet, so try to allocate
2198                         * all requested space */
2199                        start = block;
2200                        end = block + num;
2201                } else if (le32_to_cpu(ex->ee_block) > block) {
2202                        /* need to allocate space before found extent */
2203                        start = block;
2204                        end = le32_to_cpu(ex->ee_block);
2205                        if (block + num < end)
2206                                end = block + num;
2207                } else if (block >= le32_to_cpu(ex->ee_block)
2208                                        + ext4_ext_get_actual_len(ex)) {
2209                        /* need to allocate space after found extent */
2210                        start = block;
2211                        end = block + num;
2212                        if (end >= next)
2213                                end = next;
2214                } else if (block >= le32_to_cpu(ex->ee_block)) {
2215                        /*
2216                         * some part of requested space is covered
2217                         * by found extent
2218                         */
2219                        start = block;
2220                        end = le32_to_cpu(ex->ee_block)
2221                                + ext4_ext_get_actual_len(ex);
2222                        if (block + num < end)
2223                                end = block + num;
2224                        exists = 1;
2225                } else {
2226                        BUG();
2227                }
2228                BUG_ON(end <= start);
2229
2230                if (!exists) {
2231                        es.es_lblk = start;
2232                        es.es_len = end - start;
2233                        es.es_pblk = 0;
2234                } else {
2235                        es.es_lblk = le32_to_cpu(ex->ee_block);
2236                        es.es_len = ext4_ext_get_actual_len(ex);
2237                        es.es_pblk = ext4_ext_pblock(ex);
2238                        if (ext4_ext_is_unwritten(ex))
2239                                flags |= FIEMAP_EXTENT_UNWRITTEN;
2240                }
2241
2242                /*
2243                 * Find delayed extent and update es accordingly. We call
2244                 * it even in !exists case to find out whether es is the
2245                 * last existing extent or not.
2246                 */
2247                next_del = ext4_find_delayed_extent(inode, &es);
2248                if (!exists && next_del) {
2249                        exists = 1;
2250                        flags |= (FIEMAP_EXTENT_DELALLOC |
2251                                  FIEMAP_EXTENT_UNKNOWN);
2252                }
2253                up_read(&EXT4_I(inode)->i_data_sem);
2254
2255                if (unlikely(es.es_len == 0)) {
2256                        EXT4_ERROR_INODE(inode, "es.es_len == 0");
2257                        err = -EFSCORRUPTED;
2258                        break;
2259                }
2260
2261                /*
2262                 * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2263                 * we need to check next == EXT_MAX_BLOCKS because it is
2264                 * possible that an extent is with unwritten and delayed
2265                 * status due to when an extent is delayed allocated and
2266                 * is allocated by fallocate status tree will track both of
2267                 * them in a extent.
2268                 *
2269                 * So we could return a unwritten and delayed extent, and
2270                 * its block is equal to 'next'.
2271                 */
2272                if (next == next_del && next == EXT_MAX_BLOCKS) {
2273                        flags |= FIEMAP_EXTENT_LAST;
2274                        if (unlikely(next_del != EXT_MAX_BLOCKS ||
2275                                     next != EXT_MAX_BLOCKS)) {
2276                                EXT4_ERROR_INODE(inode,
2277                                                 "next extent == %u, next "
2278                                                 "delalloc extent = %u",
2279                                                 next, next_del);
2280                                err = -EFSCORRUPTED;
2281                                break;
2282                        }
2283                }
2284
2285                if (exists) {
2286                        err = fiemap_fill_next_extent(fieinfo,
2287                                (__u64)es.es_lblk << blksize_bits,
2288                                (__u64)es.es_pblk << blksize_bits,
2289                                (__u64)es.es_len << blksize_bits,
2290                                flags);
2291                        if (err < 0)
2292                                break;
2293                        if (err == 1) {
2294                                err = 0;
2295                                break;
2296                        }
2297                }
2298
2299                block = es.es_lblk + es.es_len;
2300        }
2301
2302        ext4_ext_drop_refs(path);
2303        kfree(path);
2304        return err;
2305}
2306
2307/*
2308 * ext4_ext_determine_hole - determine hole around given block
2309 * @inode:      inode we lookup in
2310 * @path:       path in extent tree to @lblk
2311 * @lblk:       pointer to logical block around which we want to determine hole
2312 *
2313 * Determine hole length (and start if easily possible) around given logical
2314 * block. We don't try too hard to find the beginning of the hole but @path
2315 * actually points to extent before @lblk, we provide it.
2316 *
2317 * The function returns the length of a hole starting at @lblk. We update @lblk
2318 * to the beginning of the hole if we managed to find it.
2319 */
2320static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2321                                           struct ext4_ext_path *path,
2322                                           ext4_lblk_t *lblk)
2323{
2324        int depth = ext_depth(inode);
2325        struct ext4_extent *ex;
2326        ext4_lblk_t len;
2327
2328        ex = path[depth].p_ext;
2329        if (ex == NULL) {
2330                /* there is no extent yet, so gap is [0;-] */
2331                *lblk = 0;
2332                len = EXT_MAX_BLOCKS;
2333        } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2334                len = le32_to_cpu(ex->ee_block) - *lblk;
2335        } else if (*lblk >= le32_to_cpu(ex->ee_block)
2336                        + ext4_ext_get_actual_len(ex)) {
2337                ext4_lblk_t next;
2338
2339                *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2340                next = ext4_ext_next_allocated_block(path);
2341                BUG_ON(next == *lblk);
2342                len = next - *lblk;
2343        } else {
2344                BUG();
2345        }
2346        return len;
2347}
2348
2349/*
2350 * ext4_ext_put_gap_in_cache:
2351 * calculate boundaries of the gap that the requested block fits into
2352 * and cache this gap
2353 */
2354static void
2355ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2356                          ext4_lblk_t hole_len)
2357{
2358        struct extent_status es;
2359
2360        ext4_es_find_delayed_extent_range(inode, hole_start,
2361                                          hole_start + hole_len - 1, &es);
2362        if (es.es_len) {
2363                /* There's delayed extent containing lblock? */
2364                if (es.es_lblk <= hole_start)
2365                        return;
2366                hole_len = min(es.es_lblk - hole_start, hole_len);
2367        }
2368        ext_debug(" -> %u:%u\n", hole_start, hole_len);
2369        ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2370                              EXTENT_STATUS_HOLE);
2371}
2372
2373/*
2374 * ext4_ext_rm_idx:
2375 * removes index from the index block.
2376 */
2377static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2378                        struct ext4_ext_path *path, int depth)
2379{
2380        int err;
2381        ext4_fsblk_t leaf;
2382
2383        /* free index block */
2384        depth--;
2385        path = path + depth;
2386        leaf = ext4_idx_pblock(path->p_idx);
2387        if (unlikely(path->p_hdr->eh_entries == 0)) {
2388                EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2389                return -EFSCORRUPTED;
2390        }
2391        err = ext4_ext_get_access(handle, inode, path);
2392        if (err)
2393                return err;
2394
2395        if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2396                int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2397                len *= sizeof(struct ext4_extent_idx);
2398                memmove(path->p_idx, path->p_idx + 1, len);
2399        }
2400
2401        le16_add_cpu(&path->p_hdr->eh_entries, -1);
2402        err = ext4_ext_dirty(handle, inode, path);
2403        if (err)
2404                return err;
2405        ext_debug("index is empty, remove it, free block %llu\n", leaf);
2406        trace_ext4_ext_rm_idx(inode, leaf);
2407
2408        ext4_free_blocks(handle, inode, NULL, leaf, 1,
2409                         EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2410
2411        while (--depth >= 0) {
2412                if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2413                        break;
2414                path--;
2415                err = ext4_ext_get_access(handle, inode, path);
2416                if (err)
2417                        break;
2418                path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2419                err = ext4_ext_dirty(handle, inode, path);
2420                if (err)
2421                        break;
2422        }
2423        return err;
2424}
2425
2426/*
2427 * ext4_ext_calc_credits_for_single_extent:
2428 * This routine returns max. credits that needed to insert an extent
2429 * to the extent tree.
2430 * When pass the actual path, the caller should calculate credits
2431 * under i_data_sem.
2432 */
2433int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2434                                                struct ext4_ext_path *path)
2435{
2436        if (path) {
2437                int depth = ext_depth(inode);
2438                int ret = 0;
2439
2440                /* probably there is space in leaf? */
2441                if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2442                                < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2443
2444                        /*
2445                         *  There are some space in the leaf tree, no
2446                         *  need to account for leaf block credit
2447                         *
2448                         *  bitmaps and block group descriptor blocks
2449                         *  and other metadata blocks still need to be
2450                         *  accounted.
2451                         */
2452                        /* 1 bitmap, 1 block group descriptor */
2453                        ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2454                        return ret;
2455                }
2456        }
2457
2458        return ext4_chunk_trans_blocks(inode, nrblocks);
2459}
2460
2461/*
2462 * How many index/leaf blocks need to change/allocate to add @extents extents?
2463 *
2464 * If we add a single extent, then in the worse case, each tree level
2465 * index/leaf need to be changed in case of the tree split.
2466 *
2467 * If more extents are inserted, they could cause the whole tree split more
2468 * than once, but this is really rare.
2469 */
2470int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2471{
2472        int index;
2473        int depth;
2474
2475        /* If we are converting the inline data, only one is needed here. */
2476        if (ext4_has_inline_data(inode))
2477                return 1;
2478
2479        depth = ext_depth(inode);
2480
2481        if (extents <= 1)
2482                index = depth * 2;
2483        else
2484                index = depth * 3;
2485
2486        return index;
2487}
2488
2489static inline int get_default_free_blocks_flags(struct inode *inode)
2490{
2491        if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2492            ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2493                return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2494        else if (ext4_should_journal_data(inode))
2495                return EXT4_FREE_BLOCKS_FORGET;
2496        return 0;
2497}
2498
2499static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2500                              struct ext4_extent *ex,
2501                              long long *partial_cluster,
2502                              ext4_lblk_t from, ext4_lblk_t to)
2503{
2504        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2505        unsigned short ee_len = ext4_ext_get_actual_len(ex);
2506        ext4_fsblk_t pblk;
2507        int flags = get_default_free_blocks_flags(inode);
2508
2509        /*
2510         * For bigalloc file systems, we never free a partial cluster
2511         * at the beginning of the extent.  Instead, we make a note
2512         * that we tried freeing the cluster, and check to see if we
2513         * need to free it on a subsequent call to ext4_remove_blocks,
2514         * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2515         */
2516        flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2517
2518        trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2519        /*
2520         * If we have a partial cluster, and it's different from the
2521         * cluster of the last block, we need to explicitly free the
2522         * partial cluster here.
2523         */
2524        pblk = ext4_ext_pblock(ex) + ee_len - 1;
2525        if (*partial_cluster > 0 &&
2526            *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2527                ext4_free_blocks(handle, inode, NULL,
2528                                 EXT4_C2B(sbi, *partial_cluster),
2529                                 sbi->s_cluster_ratio, flags);
2530                *partial_cluster = 0;
2531        }
2532
2533#ifdef EXTENTS_STATS
2534        {
2535                struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2536                spin_lock(&sbi->s_ext_stats_lock);
2537                sbi->s_ext_blocks += ee_len;
2538                sbi->s_ext_extents++;
2539                if (ee_len < sbi->s_ext_min)
2540                        sbi->s_ext_min = ee_len;
2541                if (ee_len > sbi->s_ext_max)
2542                        sbi->s_ext_max = ee_len;
2543                if (ext_depth(inode) > sbi->s_depth_max)
2544                        sbi->s_depth_max = ext_depth(inode);
2545                spin_unlock(&sbi->s_ext_stats_lock);
2546        }
2547#endif
2548        if (from >= le32_to_cpu(ex->ee_block)
2549            && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2550                /* tail removal */
2551                ext4_lblk_t num;
2552                long long first_cluster;
2553
2554                num = le32_to_cpu(ex->ee_block) + ee_len - from;
2555                pblk = ext4_ext_pblock(ex) + ee_len - num;
2556                /*
2557                 * Usually we want to free partial cluster at the end of the
2558                 * extent, except for the situation when the cluster is still
2559                 * used by any other extent (partial_cluster is negative).
2560                 */
2561                if (*partial_cluster < 0 &&
2562                    *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))
2563                        flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2564
2565                ext_debug("free last %u blocks starting %llu partial %lld\n",
2566                          num, pblk, *partial_cluster);
2567                ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2568                /*
2569                 * If the block range to be freed didn't start at the
2570                 * beginning of a cluster, and we removed the entire
2571                 * extent and the cluster is not used by any other extent,
2572                 * save the partial cluster here, since we might need to
2573                 * delete if we determine that the truncate or punch hole
2574                 * operation has removed all of the blocks in the cluster.
2575                 * If that cluster is used by another extent, preserve its
2576                 * negative value so it isn't freed later on.
2577                 *
2578                 * If the whole extent wasn't freed, we've reached the
2579                 * start of the truncated/punched region and have finished
2580                 * removing blocks.  If there's a partial cluster here it's
2581                 * shared with the remainder of the extent and is no longer
2582                 * a candidate for removal.
2583                 */
2584                if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {
2585                        first_cluster = (long long) EXT4_B2C(sbi, pblk);
2586                        if (first_cluster != -*partial_cluster)
2587                                *partial_cluster = first_cluster;
2588                } else {
2589                        *partial_cluster = 0;
2590                }
2591        } else
2592                ext4_error(sbi->s_sb, "strange request: removal(2) "
2593                           "%u-%u from %u:%u",
2594                           from, to, le32_to_cpu(ex->ee_block), ee_len);
2595        return 0;
2596}
2597
2598
2599/*
2600 * ext4_ext_rm_leaf() Removes the extents associated with the
2601 * blocks appearing between "start" and "end".  Both "start"
2602 * and "end" must appear in the same extent or EIO is returned.
2603 *
2604 * @handle: The journal handle
2605 * @inode:  The files inode
2606 * @path:   The path to the leaf
2607 * @partial_cluster: The cluster which we'll have to free if all extents
2608 *                   has been released from it.  However, if this value is
2609 *                   negative, it's a cluster just to the right of the
2610 *                   punched region and it must not be freed.
2611 * @start:  The first block to remove
2612 * @end:   The last block to remove
2613 */
2614static int
2615ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2616                 struct ext4_ext_path *path,
2617                 long long *partial_cluster,
2618                 ext4_lblk_t start, ext4_lblk_t end)
2619{
2620        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2621        int err = 0, correct_index = 0;
2622        int depth = ext_depth(inode), credits;
2623        struct ext4_extent_header *eh;
2624        ext4_lblk_t a, b;
2625        unsigned num;
2626        ext4_lblk_t ex_ee_block;
2627        unsigned short ex_ee_len;
2628        unsigned unwritten = 0;
2629        struct ext4_extent *ex;
2630        ext4_fsblk_t pblk;
2631
2632        /* the header must be checked already in ext4_ext_remove_space() */
2633        ext_debug("truncate since %u in leaf to %u\n", start, end);
2634        if (!path[depth].p_hdr)
2635                path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2636        eh = path[depth].p_hdr;
2637        if (unlikely(path[depth].p_hdr == NULL)) {
2638                EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2639                return -EFSCORRUPTED;
2640        }
2641        /* find where to start removing */
2642        ex = path[depth].p_ext;
2643        if (!ex)
2644                ex = EXT_LAST_EXTENT(eh);
2645
2646        ex_ee_block = le32_to_cpu(ex->ee_block);
2647        ex_ee_len = ext4_ext_get_actual_len(ex);
2648
2649        trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2650
2651        while (ex >= EXT_FIRST_EXTENT(eh) &&
2652                        ex_ee_block + ex_ee_len > start) {
2653
2654                if (ext4_ext_is_unwritten(ex))
2655                        unwritten = 1;
2656                else
2657                        unwritten = 0;
2658
2659                ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2660                          unwritten, ex_ee_len);
2661                path[depth].p_ext = ex;
2662
2663                a = ex_ee_block > start ? ex_ee_block : start;
2664                b = ex_ee_block+ex_ee_len - 1 < end ?
2665                        ex_ee_block+ex_ee_len - 1 : end;
2666
2667                ext_debug("  border %u:%u\n", a, b);
2668
2669                /* If this extent is beyond the end of the hole, skip it */
2670                if (end < ex_ee_block) {
2671                        /*
2672                         * We're going to skip this extent and move to another,
2673                         * so note that its first cluster is in use to avoid
2674                         * freeing it when removing blocks.  Eventually, the
2675                         * right edge of the truncated/punched region will
2676                         * be just to the left.
2677                         */
2678                        if (sbi->s_cluster_ratio > 1) {
2679                                pblk = ext4_ext_pblock(ex);
2680                                *partial_cluster =
2681                                        -(long long) EXT4_B2C(sbi, pblk);
2682                        }
2683                        ex--;
2684                        ex_ee_block = le32_to_cpu(ex->ee_block);
2685                        ex_ee_len = ext4_ext_get_actual_len(ex);
2686                        continue;
2687                } else if (b != ex_ee_block + ex_ee_len - 1) {
2688                        EXT4_ERROR_INODE(inode,
2689                                         "can not handle truncate %u:%u "
2690                                         "on extent %u:%u",
2691                                         start, end, ex_ee_block,
2692                                         ex_ee_block + ex_ee_len - 1);
2693                        err = -EFSCORRUPTED;
2694                        goto out;
2695                } else if (a != ex_ee_block) {
2696                        /* remove tail of the extent */
2697                        num = a - ex_ee_block;
2698                } else {
2699                        /* remove whole extent: excellent! */
2700                        num = 0;
2701                }
2702                /*
2703                 * 3 for leaf, sb, and inode plus 2 (bmap and group
2704                 * descriptor) for each block group; assume two block
2705                 * groups plus ex_ee_len/blocks_per_block_group for
2706                 * the worst case
2707                 */
2708                credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2709                if (ex == EXT_FIRST_EXTENT(eh)) {
2710                        correct_index = 1;
2711                        credits += (ext_depth(inode)) + 1;
2712                }
2713                credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2714
2715                err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2716                if (err)
2717                        goto out;
2718
2719                err = ext4_ext_get_access(handle, inode, path + depth);
2720                if (err)
2721                        goto out;
2722
2723                err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2724                                         a, b);
2725                if (err)
2726                        goto out;
2727
2728                if (num == 0)
2729                        /* this extent is removed; mark slot entirely unused */
2730                        ext4_ext_store_pblock(ex, 0);
2731
2732                ex->ee_len = cpu_to_le16(num);
2733                /*
2734                 * Do not mark unwritten if all the blocks in the
2735                 * extent have been removed.
2736                 */
2737                if (unwritten && num)
2738                        ext4_ext_mark_unwritten(ex);
2739                /*
2740                 * If the extent was completely released,
2741                 * we need to remove it from the leaf
2742                 */
2743                if (num == 0) {
2744                        if (end != EXT_MAX_BLOCKS - 1) {
2745                                /*
2746                                 * For hole punching, we need to scoot all the
2747                                 * extents up when an extent is removed so that
2748                                 * we dont have blank extents in the middle
2749                                 */
2750                                memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2751                                        sizeof(struct ext4_extent));
2752
2753                                /* Now get rid of the one at the end */
2754                                memset(EXT_LAST_EXTENT(eh), 0,
2755                                        sizeof(struct ext4_extent));
2756                        }
2757                        le16_add_cpu(&eh->eh_entries, -1);
2758                }
2759
2760                err = ext4_ext_dirty(handle, inode, path + depth);
2761                if (err)
2762                        goto out;
2763
2764                ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2765                                ext4_ext_pblock(ex));
2766                ex--;
2767                ex_ee_block = le32_to_cpu(ex->ee_block);
2768                ex_ee_len = ext4_ext_get_actual_len(ex);
2769        }
2770
2771        if (correct_index && eh->eh_entries)
2772                err = ext4_ext_correct_indexes(handle, inode, path);
2773
2774        /*
2775         * If there's a partial cluster and at least one extent remains in
2776         * the leaf, free the partial cluster if it isn't shared with the
2777         * current extent.  If it is shared with the current extent
2778         * we zero partial_cluster because we've reached the start of the
2779         * truncated/punched region and we're done removing blocks.
2780         */
2781        if (*partial_cluster > 0 && ex >= EXT_FIRST_EXTENT(eh)) {
2782                pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2783                if (*partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2784                        ext4_free_blocks(handle, inode, NULL,
2785                                         EXT4_C2B(sbi, *partial_cluster),
2786                                         sbi->s_cluster_ratio,
2787                                         get_default_free_blocks_flags(inode));
2788                }
2789                *partial_cluster = 0;
2790        }
2791
2792        /* if this leaf is free, then we should
2793         * remove it from index block above */
2794        if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2795                err = ext4_ext_rm_idx(handle, inode, path, depth);
2796
2797out:
2798        return err;
2799}
2800
2801/*
2802 * ext4_ext_more_to_rm:
2803 * returns 1 if current index has to be freed (even partial)
2804 */
2805static int
2806ext4_ext_more_to_rm(struct ext4_ext_path *path)
2807{
2808        BUG_ON(path->p_idx == NULL);
2809
2810        if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2811                return 0;
2812
2813        /*
2814         * if truncate on deeper level happened, it wasn't partial,
2815         * so we have to consider current index for truncation
2816         */
2817        if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2818                return 0;
2819        return 1;
2820}
2821
2822int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2823                          ext4_lblk_t end)
2824{
2825        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2826        int depth = ext_depth(inode);
2827        struct ext4_ext_path *path = NULL;
2828        long long partial_cluster = 0;
2829        handle_t *handle;
2830        int i = 0, err = 0;
2831
2832        ext_debug("truncate since %u to %u\n", start, end);
2833
2834        /* probably first extent we're gonna free will be last in block */
2835        handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2836        if (IS_ERR(handle))
2837                return PTR_ERR(handle);
2838
2839again:
2840        trace_ext4_ext_remove_space(inode, start, end, depth);
2841
2842        /*
2843         * Check if we are removing extents inside the extent tree. If that
2844         * is the case, we are going to punch a hole inside the extent tree
2845         * so we have to check whether we need to split the extent covering
2846         * the last block to remove so we can easily remove the part of it
2847         * in ext4_ext_rm_leaf().
2848         */
2849        if (end < EXT_MAX_BLOCKS - 1) {
2850                struct ext4_extent *ex;
2851                ext4_lblk_t ee_block, ex_end, lblk;
2852                ext4_fsblk_t pblk;
2853
2854                /* find extent for or closest extent to this block */
2855                path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2856                if (IS_ERR(path)) {
2857                        ext4_journal_stop(handle);
2858                        return PTR_ERR(path);
2859                }
2860                depth = ext_depth(inode);
2861                /* Leaf not may not exist only if inode has no blocks at all */
2862                ex = path[depth].p_ext;
2863                if (!ex) {
2864                        if (depth) {
2865                                EXT4_ERROR_INODE(inode,
2866                                                 "path[%d].p_hdr == NULL",
2867                                                 depth);
2868                                err = -EFSCORRUPTED;
2869                        }
2870                        goto out;
2871                }
2872
2873                ee_block = le32_to_cpu(ex->ee_block);
2874                ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2875
2876                /*
2877                 * See if the last block is inside the extent, if so split
2878                 * the extent at 'end' block so we can easily remove the
2879                 * tail of the first part of the split extent in
2880                 * ext4_ext_rm_leaf().
2881                 */
2882                if (end >= ee_block && end < ex_end) {
2883
2884                        /*
2885                         * If we're going to split the extent, note that
2886                         * the cluster containing the block after 'end' is
2887                         * in use to avoid freeing it when removing blocks.
2888                         */
2889                        if (sbi->s_cluster_ratio > 1) {
2890                                pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2891                                partial_cluster =
2892                                        -(long long) EXT4_B2C(sbi, pblk);
2893                        }
2894
2895                        /*
2896                         * Split the extent in two so that 'end' is the last
2897                         * block in the first new extent. Also we should not
2898                         * fail removing space due to ENOSPC so try to use
2899                         * reserved block if that happens.
2900                         */
2901                        err = ext4_force_split_extent_at(handle, inode, &path,
2902                                                         end + 1, 1);
2903                        if (err < 0)
2904                                goto out;
2905
2906                } else if (sbi->s_cluster_ratio > 1 && end >= ex_end) {
2907                        /*
2908                         * If there's an extent to the right its first cluster
2909                         * contains the immediate right boundary of the
2910                         * truncated/punched region.  Set partial_cluster to
2911                         * its negative value so it won't be freed if shared
2912                         * with the current extent.  The end < ee_block case
2913                         * is handled in ext4_ext_rm_leaf().
2914                         */
2915                        lblk = ex_end + 1;
2916                        err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2917                                                    &ex);
2918                        if (err)
2919                                goto out;
2920                        if (pblk)
2921                                partial_cluster =
2922                                        -(long long) EXT4_B2C(sbi, pblk);
2923                }
2924        }
2925        /*
2926         * We start scanning from right side, freeing all the blocks
2927         * after i_size and walking into the tree depth-wise.
2928         */
2929        depth = ext_depth(inode);
2930        if (path) {
2931                int k = i = depth;
2932                while (--k > 0)
2933                        path[k].p_block =
2934                                le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2935        } else {
2936                path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2937                               GFP_NOFS);
2938                if (path == NULL) {
2939                        ext4_journal_stop(handle);
2940                        return -ENOMEM;
2941                }
2942                path[0].p_maxdepth = path[0].p_depth = depth;
2943                path[0].p_hdr = ext_inode_hdr(inode);
2944                i = 0;
2945
2946                if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2947                        err = -EFSCORRUPTED;
2948                        goto out;
2949                }
2950        }
2951        err = 0;
2952
2953        while (i >= 0 && err == 0) {
2954                if (i == depth) {
2955                        /* this is leaf block */
2956                        err = ext4_ext_rm_leaf(handle, inode, path,
2957                                               &partial_cluster, start,
2958                                               end);
2959                        /* root level has p_bh == NULL, brelse() eats this */
2960                        brelse(path[i].p_bh);
2961                        path[i].p_bh = NULL;
2962                        i--;
2963                        continue;
2964                }
2965
2966                /* this is index block */
2967                if (!path[i].p_hdr) {
2968                        ext_debug("initialize header\n");
2969                        path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2970                }
2971
2972                if (!path[i].p_idx) {
2973                        /* this level hasn't been touched yet */
2974                        path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2975                        path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2976                        ext_debug("init index ptr: hdr 0x%p, num %d\n",
2977                                  path[i].p_hdr,
2978                                  le16_to_cpu(path[i].p_hdr->eh_entries));
2979                } else {
2980                        /* we were already here, see at next index */
2981                        path[i].p_idx--;
2982                }
2983
2984                ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2985                                i, EXT_FIRST_INDEX(path[i].p_hdr),
2986                                path[i].p_idx);
2987                if (ext4_ext_more_to_rm(path + i)) {
2988                        struct buffer_head *bh;
2989                        /* go to the next level */
2990                        ext_debug("move to level %d (block %llu)\n",
2991                                  i + 1, ext4_idx_pblock(path[i].p_idx));
2992                        memset(path + i + 1, 0, sizeof(*path));
2993                        bh = read_extent_tree_block(inode,
2994                                ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2995                                EXT4_EX_NOCACHE);
2996                        if (IS_ERR(bh)) {
2997                                /* should we reset i_size? */
2998                                err = PTR_ERR(bh);
2999                                break;
3000                        }
3001                        /* Yield here to deal with large extent trees.
3002                         * Should be a no-op if we did IO above. */
3003                        cond_resched();
3004                        if (WARN_ON(i + 1 > depth)) {
3005                                err = -EFSCORRUPTED;
3006                                break;
3007                        }
3008                        path[i + 1].p_bh = bh;
3009
3010                        /* save actual number of indexes since this
3011                         * number is changed at the next iteration */
3012                        path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3013                        i++;
3014                } else {
3015                        /* we finished processing this index, go up */
3016                        if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3017                                /* index is empty, remove it;
3018                                 * handle must be already prepared by the
3019                                 * truncatei_leaf() */
3020                                err = ext4_ext_rm_idx(handle, inode, path, i);
3021                        }
3022                        /* root level has p_bh == NULL, brelse() eats this */
3023                        brelse(path[i].p_bh);
3024                        path[i].p_bh = NULL;
3025                        i--;
3026                        ext_debug("return to level %d\n", i);
3027                }
3028        }
3029
3030        trace_ext4_ext_remove_space_done(inode, start, end, depth,
3031                        partial_cluster, path->p_hdr->eh_entries);
3032
3033        /*
3034         * If we still have something in the partial cluster and we have removed
3035         * even the first extent, then we should free the blocks in the partial
3036         * cluster as well.  (This code will only run when there are no leaves
3037         * to the immediate left of the truncated/punched region.)
3038         */
3039        if (partial_cluster > 0 && err == 0) {
3040                /* don't zero partial_cluster since it's not used afterwards */
3041                ext4_free_blocks(handle, inode, NULL,
3042                                 EXT4_C2B(sbi, partial_cluster),
3043                                 sbi->s_cluster_ratio,
3044                                 get_default_free_blocks_flags(inode));
3045        }
3046
3047        /* TODO: flexible tree reduction should be here */
3048        if (path->p_hdr->eh_entries == 0) {
3049                /*
3050                 * truncate to zero freed all the tree,
3051                 * so we need to correct eh_depth
3052                 */
3053                err = ext4_ext_get_access(handle, inode, path);
3054                if (err == 0) {
3055                        ext_inode_hdr(inode)->eh_depth = 0;
3056                        ext_inode_hdr(inode)->eh_max =
3057                                cpu_to_le16(ext4_ext_space_root(inode, 0));
3058                        err = ext4_ext_dirty(handle, inode, path);
3059                }
3060        }
3061out:
3062        ext4_ext_drop_refs(path);
3063        kfree(path);
3064        path = NULL;
3065        if (err == -EAGAIN)
3066                goto again;
3067        ext4_journal_stop(handle);
3068
3069        return err;
3070}
3071
3072/*
3073 * called at mount time
3074 */
3075void ext4_ext_init(struct super_block *sb)
3076{
3077        /*
3078         * possible initialization would be here
3079         */
3080
3081        if (ext4_has_feature_extents(sb)) {
3082#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3083                printk(KERN_INFO "EXT4-fs: file extents enabled"
3084#ifdef AGGRESSIVE_TEST
3085                       ", aggressive tests"
3086#endif
3087#ifdef CHECK_BINSEARCH
3088                       ", check binsearch"
3089#endif
3090#ifdef EXTENTS_STATS
3091                       ", stats"
3092#endif
3093                       "\n");
3094#endif
3095#ifdef EXTENTS_STATS
3096                spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3097                EXT4_SB(sb)->s_ext_min = 1 << 30;
3098                EXT4_SB(sb)->s_ext_max = 0;
3099#endif
3100        }
3101}
3102
3103/*
3104 * called at umount time
3105 */
3106void ext4_ext_release(struct super_block *sb)
3107{
3108        if (!ext4_has_feature_extents(sb))
3109                return;
3110
3111#ifdef EXTENTS_STATS
3112        if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3113                struct ext4_sb_info *sbi = EXT4_SB(sb);
3114                printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3115                        sbi->s_ext_blocks, sbi->s_ext_extents,
3116                        sbi->s_ext_blocks / sbi->s_ext_extents);
3117                printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3118                        sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3119        }
3120#endif
3121}
3122
3123static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3124{
3125        ext4_lblk_t  ee_block;
3126        ext4_fsblk_t ee_pblock;
3127        unsigned int ee_len;
3128
3129        ee_block  = le32_to_cpu(ex->ee_block);
3130        ee_len    = ext4_ext_get_actual_len(ex);
3131        ee_pblock = ext4_ext_pblock(ex);
3132
3133        if (ee_len == 0)
3134                return 0;
3135
3136        return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3137                                     EXTENT_STATUS_WRITTEN);
3138}
3139
3140/* FIXME!! we need to try to merge to left or right after zero-out  */
3141static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3142{
3143        ext4_fsblk_t ee_pblock;
3144        unsigned int ee_len;
3145
3146        ee_len    = ext4_ext_get_actual_len(ex);
3147        ee_pblock = ext4_ext_pblock(ex);
3148        return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3149                                  ee_len);
3150}
3151
3152/*
3153 * ext4_split_extent_at() splits an extent at given block.
3154 *
3155 * @handle: the journal handle
3156 * @inode: the file inode
3157 * @path: the path to the extent
3158 * @split: the logical block where the extent is splitted.
3159 * @split_flags: indicates if the extent could be zeroout if split fails, and
3160 *               the states(init or unwritten) of new extents.
3161 * @flags: flags used to insert new extent to extent tree.
3162 *
3163 *
3164 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3165 * of which are deterimined by split_flag.
3166 *
3167 * There are two cases:
3168 *  a> the extent are splitted into two extent.
3169 *  b> split is not needed, and just mark the extent.
3170 *
3171 * return 0 on success.
3172 */
3173static int ext4_split_extent_at(handle_t *handle,
3174                             struct inode *inode,
3175                             struct ext4_ext_path **ppath,
3176                             ext4_lblk_t split,
3177                             int split_flag,
3178                             int flags)
3179{
3180        struct ext4_ext_path *path = *ppath;
3181        ext4_fsblk_t newblock;
3182        ext4_lblk_t ee_block;
3183        struct ext4_extent *ex, newex, orig_ex, zero_ex;
3184        struct ext4_extent *ex2 = NULL;
3185        unsigned int ee_len, depth;
3186        int err = 0;
3187
3188        BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3189               (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3190
3191        ext_debug("ext4_split_extents_at: inode %lu, logical"
3192                "block %llu\n", inode->i_ino, (unsigned long long)split);
3193
3194        ext4_ext_show_leaf(inode, path);
3195
3196        depth = ext_depth(inode);
3197        ex = path[depth].p_ext;
3198        ee_block = le32_to_cpu(ex->ee_block);
3199        ee_len = ext4_ext_get_actual_len(ex);
3200        newblock = split - ee_block + ext4_ext_pblock(ex);
3201
3202        BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3203        BUG_ON(!ext4_ext_is_unwritten(ex) &&
3204               split_flag & (EXT4_EXT_MAY_ZEROOUT |
3205                             EXT4_EXT_MARK_UNWRIT1 |
3206                             EXT4_EXT_MARK_UNWRIT2));
3207
3208        err = ext4_ext_get_access(handle, inode, path + depth);
3209        if (err)
3210                goto out;
3211
3212        if (split == ee_block) {
3213                /*
3214                 * case b: block @split is the block that the extent begins with
3215                 * then we just change the state of the extent, and splitting
3216                 * is not needed.
3217                 */
3218                if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3219                        ext4_ext_mark_unwritten(ex);
3220                else
3221                        ext4_ext_mark_initialized(ex);
3222
3223                if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3224                        ext4_ext_try_to_merge(handle, inode, path, ex);
3225
3226                err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3227                goto out;
3228        }
3229
3230        /* case a */
3231        memcpy(&orig_ex, ex, sizeof(orig_ex));
3232        ex->ee_len = cpu_to_le16(split - ee_block);
3233        if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3234                ext4_ext_mark_unwritten(ex);
3235
3236        /*
3237         * path may lead to new leaf, not to original leaf any more
3238         * after ext4_ext_insert_extent() returns,
3239         */
3240        err = ext4_ext_dirty(handle, inode, path + depth);
3241        if (err)
3242                goto fix_extent_len;
3243
3244        ex2 = &newex;
3245        ex2->ee_block = cpu_to_le32(split);
3246        ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3247        ext4_ext_store_pblock(ex2, newblock);
3248        if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3249                ext4_ext_mark_unwritten(ex2);
3250
3251        err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3252        if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3253                if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3254                        if (split_flag & EXT4_EXT_DATA_VALID1) {
3255                                err = ext4_ext_zeroout(inode, ex2);
3256                                zero_ex.ee_block = ex2->ee_block;
3257                                zero_ex.ee_len = cpu_to_le16(
3258                                                ext4_ext_get_actual_len(ex2));
3259                                ext4_ext_store_pblock(&zero_ex,
3260                                                      ext4_ext_pblock(ex2));
3261                        } else {
3262                                err = ext4_ext_zeroout(inode, ex);
3263                                zero_ex.ee_block = ex->ee_block;
3264                                zero_ex.ee_len = cpu_to_le16(
3265                                                ext4_ext_get_actual_len(ex));
3266                                ext4_ext_store_pblock(&zero_ex,
3267                                                      ext4_ext_pblock(ex));
3268                        }
3269                } else {
3270                        err = ext4_ext_zeroout(inode, &orig_ex);
3271                        zero_ex.ee_block = orig_ex.ee_block;
3272                        zero_ex.ee_len = cpu_to_le16(
3273                                                ext4_ext_get_actual_len(&orig_ex));
3274                        ext4_ext_store_pblock(&zero_ex,
3275                                              ext4_ext_pblock(&orig_ex));
3276                }
3277
3278                if (err)
3279                        goto fix_extent_len;
3280                /* update the extent length and mark as initialized */
3281                ex->ee_len = cpu_to_le16(ee_len);
3282                ext4_ext_try_to_merge(handle, inode, path, ex);
3283                err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3284                if (err)
3285                        goto fix_extent_len;
3286
3287                /* update extent status tree */
3288                err = ext4_zeroout_es(inode, &zero_ex);
3289
3290                goto out;
3291        } else if (err)
3292                goto fix_extent_len;
3293
3294out:
3295        ext4_ext_show_leaf(inode, path);
3296        return err;
3297
3298fix_extent_len:
3299        ex->ee_len = orig_ex.ee_len;
3300        ext4_ext_dirty(handle, inode, path + path->p_depth);
3301        return err;
3302}
3303
3304/*
3305 * ext4_split_extents() splits an extent and mark extent which is covered
3306 * by @map as split_flags indicates
3307 *
3308 * It may result in splitting the extent into multiple extents (up to three)
3309 * There are three possibilities:
3310 *   a> There is no split required
3311 *   b> Splits in two extents: Split is happening at either end of the extent
3312 *   c> Splits in three extents: Somone is splitting in middle of the extent
3313 *
3314 */
3315static int ext4_split_extent(handle_t *handle,
3316                              struct inode *inode,
3317                              struct ext4_ext_path **ppath,
3318                              struct ext4_map_blocks *map,
3319                              int split_flag,
3320                              int flags)
3321{
3322        struct ext4_ext_path *path = *ppath;
3323        ext4_lblk_t ee_block;
3324        struct ext4_extent *ex;
3325        unsigned int ee_len, depth;
3326        int err = 0;
3327        int unwritten;
3328        int split_flag1, flags1;
3329        int allocated = map->m_len;
3330
3331        depth = ext_depth(inode);
3332        ex = path[depth].p_ext;
3333        ee_block = le32_to_cpu(ex->ee_block);
3334        ee_len = ext4_ext_get_actual_len(ex);
3335        unwritten = ext4_ext_is_unwritten(ex);
3336
3337        if (map->m_lblk + map->m_len < ee_block + ee_len) {
3338                split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3339                flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3340                if (unwritten)
3341                        split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3342                                       EXT4_EXT_MARK_UNWRIT2;
3343                if (split_flag & EXT4_EXT_DATA_VALID2)
3344                        split_flag1 |= EXT4_EXT_DATA_VALID1;
3345                err = ext4_split_extent_at(handle, inode, ppath,
3346                                map->m_lblk + map->m_len, split_flag1, flags1);
3347                if (err)
3348                        goto out;
3349        } else {
3350                allocated = ee_len - (map->m_lblk - ee_block);
3351        }
3352        /*
3353         * Update path is required because previous ext4_split_extent_at() may
3354         * result in split of original leaf or extent zeroout.
3355         */
3356        path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3357        if (IS_ERR(path))
3358                return PTR_ERR(path);
3359        depth = ext_depth(inode);
3360        ex = path[depth].p_ext;
3361        if (!ex) {
3362                EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3363                                 (unsigned long) map->m_lblk);
3364                return -EFSCORRUPTED;
3365        }
3366        unwritten = ext4_ext_is_unwritten(ex);
3367        split_flag1 = 0;
3368
3369        if (map->m_lblk >= ee_block) {
3370                split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3371                if (unwritten) {
3372                        split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3373                        split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3374                                                     EXT4_EXT_MARK_UNWRIT2);
3375                }
3376                err = ext4_split_extent_at(handle, inode, ppath,
3377                                map->m_lblk, split_flag1, flags);
3378                if (err)
3379                        goto out;
3380        }
3381
3382        ext4_ext_show_leaf(inode, path);
3383out:
3384        return err ? err : allocated;
3385}
3386
3387/*
3388 * This function is called by ext4_ext_map_blocks() if someone tries to write
3389 * to an unwritten extent. It may result in splitting the unwritten
3390 * extent into multiple extents (up to three - one initialized and two
3391 * unwritten).
3392 * There are three possibilities:
3393 *   a> There is no split required: Entire extent should be initialized
3394 *   b> Splits in two extents: Write is happening at either end of the extent
3395 *   c> Splits in three extents: Somone is writing in middle of the extent
3396 *
3397 * Pre-conditions:
3398 *  - The extent pointed to by 'path' is unwritten.
3399 *  - The extent pointed to by 'path' contains a superset
3400 *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3401 *
3402 * Post-conditions on success:
3403 *  - the returned value is the number of blocks beyond map->l_lblk
3404 *    that are allocated and initialized.
3405 *    It is guaranteed to be >= map->m_len.
3406 */
3407static int ext4_ext_convert_to_initialized(handle_t *handle,
3408                                           struct inode *inode,
3409                                           struct ext4_map_blocks *map,
3410                                           struct ext4_ext_path **ppath,
3411                                           int flags)
3412{
3413        struct ext4_ext_path *path = *ppath;
3414        struct ext4_sb_info *sbi;
3415        struct ext4_extent_header *eh;
3416        struct ext4_map_blocks split_map;
3417        struct ext4_extent zero_ex1, zero_ex2;
3418        struct ext4_extent *ex, *abut_ex;
3419        ext4_lblk_t ee_block, eof_block;
3420        unsigned int ee_len, depth, map_len = map->m_len;
3421        int allocated = 0, max_zeroout = 0;
3422        int err = 0;
3423        int split_flag = EXT4_EXT_DATA_VALID2;
3424
3425        ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3426                "block %llu, max_blocks %u\n", inode->i_ino,
3427                (unsigned long long)map->m_lblk, map_len);
3428
3429        sbi = EXT4_SB(inode->i_sb);
3430        eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3431                inode->i_sb->s_blocksize_bits;
3432        if (eof_block < map->m_lblk + map_len)
3433                eof_block = map->m_lblk + map_len;
3434
3435        depth = ext_depth(inode);
3436        eh = path[depth].p_hdr;
3437        ex = path[depth].p_ext;
3438        ee_block = le32_to_cpu(ex->ee_block);
3439        ee_len = ext4_ext_get_actual_len(ex);
3440        zero_ex1.ee_len = 0;
3441        zero_ex2.ee_len = 0;
3442
3443        trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3444
3445        /* Pre-conditions */
3446        BUG_ON(!ext4_ext_is_unwritten(ex));
3447        BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3448
3449        /*
3450         * Attempt to transfer newly initialized blocks from the currently
3451         * unwritten extent to its neighbor. This is much cheaper
3452         * than an insertion followed by a merge as those involve costly
3453         * memmove() calls. Transferring to the left is the common case in
3454         * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3455         * followed by append writes.
3456         *
3457         * Limitations of the current logic:
3458         *  - L1: we do not deal with writes covering the whole extent.
3459         *    This would require removing the extent if the transfer
3460         *    is possible.
3461         *  - L2: we only attempt to merge with an extent stored in the
3462         *    same extent tree node.
3463         */
3464        if ((map->m_lblk == ee_block) &&
3465                /* See if we can merge left */
3466                (map_len < ee_len) &&           /*L1*/
3467                (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3468                ext4_lblk_t prev_lblk;
3469                ext4_fsblk_t prev_pblk, ee_pblk;
3470                unsigned int prev_len;
3471
3472                abut_ex = ex - 1;
3473                prev_lblk = le32_to_cpu(abut_ex->ee_block);
3474                prev_len = ext4_ext_get_actual_len(abut_ex);
3475                prev_pblk = ext4_ext_pblock(abut_ex);
3476                ee_pblk = ext4_ext_pblock(ex);
3477
3478                /*
3479                 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3480                 * upon those conditions:
3481                 * - C1: abut_ex is initialized,
3482                 * - C2: abut_ex is logically abutting ex,
3483                 * - C3: abut_ex is physically abutting ex,
3484                 * - C4: abut_ex can receive the additional blocks without
3485                 *   overflowing the (initialized) length limit.
3486                 */
3487                if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3488                        ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3489                        ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3490                        (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3491                        err = ext4_ext_get_access(handle, inode, path + depth);
3492                        if (err)
3493                                goto out;
3494
3495                        trace_ext4_ext_convert_to_initialized_fastpath(inode,
3496                                map, ex, abut_ex);
3497
3498                        /* Shift the start of ex by 'map_len' blocks */
3499                        ex->ee_block = cpu_to_le32(ee_block + map_len);
3500                        ext4_ext_store_pblock(ex, ee_pblk + map_len);
3501                        ex->ee_len = cpu_to_le16(ee_len - map_len);
3502                        ext4_ext_mark_unwritten(ex); /* Restore the flag */
3503
3504                        /* Extend abut_ex by 'map_len' blocks */
3505                        abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3506
3507                        /* Result: number of initialized blocks past m_lblk */
3508                        allocated = map_len;
3509                }
3510        } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3511                   (map_len < ee_len) &&        /*L1*/
3512                   ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3513                /* See if we can merge right */
3514                ext4_lblk_t next_lblk;
3515                ext4_fsblk_t next_pblk, ee_pblk;
3516                unsigned int next_len;
3517
3518                abut_ex = ex + 1;
3519                next_lblk = le32_to_cpu(abut_ex->ee_block);
3520                next_len = ext4_ext_get_actual_len(abut_ex);
3521                next_pblk = ext4_ext_pblock(abut_ex);
3522                ee_pblk = ext4_ext_pblock(ex);
3523
3524                /*
3525                 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3526                 * upon those conditions:
3527                 * - C1: abut_ex is initialized,
3528                 * - C2: abut_ex is logically abutting ex,
3529                 * - C3: abut_ex is physically abutting ex,
3530                 * - C4: abut_ex can receive the additional blocks without
3531                 *   overflowing the (initialized) length limit.
3532                 */
3533                if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3534                    ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3535                    ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3536                    (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3537                        err = ext4_ext_get_access(handle, inode, path + depth);
3538                        if (err)
3539                                goto out;
3540
3541                        trace_ext4_ext_convert_to_initialized_fastpath(inode,
3542                                map, ex, abut_ex);
3543
3544                        /* Shift the start of abut_ex by 'map_len' blocks */
3545                        abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3546                        ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3547                        ex->ee_len = cpu_to_le16(ee_len - map_len);
3548                        ext4_ext_mark_unwritten(ex); /* Restore the flag */
3549
3550                        /* Extend abut_ex by 'map_len' blocks */
3551                        abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3552
3553                        /* Result: number of initialized blocks past m_lblk */
3554                        allocated = map_len;
3555                }
3556        }
3557        if (allocated) {
3558                /* Mark the block containing both extents as dirty */
3559                ext4_ext_dirty(handle, inode, path + depth);
3560
3561                /* Update path to point to the right extent */
3562                path[depth].p_ext = abut_ex;
3563                goto out;
3564        } else
3565                allocated = ee_len - (map->m_lblk - ee_block);
3566
3567        WARN_ON(map->m_lblk < ee_block);
3568        /*
3569         * It is safe to convert extent to initialized via explicit
3570         * zeroout only if extent is fully inside i_size or new_size.
3571         */
3572        split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3573
3574        if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3575                max_zeroout = sbi->s_extent_max_zeroout_kb >>
3576                        (inode->i_sb->s_blocksize_bits - 10);
3577
3578        if (ext4_encrypted_inode(inode))
3579                max_zeroout = 0;
3580
3581        /*
3582         * five cases:
3583         * 1. split the extent into three extents.
3584         * 2. split the extent into two extents, zeroout the head of the first
3585         *    extent.
3586         * 3. split the extent into two extents, zeroout the tail of the second
3587         *    extent.
3588         * 4. split the extent into two extents with out zeroout.
3589         * 5. no splitting needed, just possibly zeroout the head and / or the
3590         *    tail of the extent.
3591         */
3592        split_map.m_lblk = map->m_lblk;
3593        split_map.m_len = map->m_len;
3594
3595        if (max_zeroout && (allocated > split_map.m_len)) {
3596                if (allocated <= max_zeroout) {
3597                        /* case 3 or 5 */
3598                        zero_ex1.ee_block =
3599                                 cpu_to_le32(split_map.m_lblk +
3600                                             split_map.m_len);
3601                        zero_ex1.ee_len =
3602                                cpu_to_le16(allocated - split_map.m_len);
3603                        ext4_ext_store_pblock(&zero_ex1,
3604                                ext4_ext_pblock(ex) + split_map.m_lblk +
3605                                split_map.m_len - ee_block);
3606                        err = ext4_ext_zeroout(inode, &zero_ex1);
3607                        if (err)
3608                                goto out;
3609                        split_map.m_len = allocated;
3610                }
3611                if (split_map.m_lblk - ee_block + split_map.m_len <
3612                                                                max_zeroout) {
3613                        /* case 2 or 5 */
3614                        if (split_map.m_lblk != ee_block) {
3615                                zero_ex2.ee_block = ex->ee_block;
3616                                zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3617                                                        ee_block);
3618                                ext4_ext_store_pblock(&zero_ex2,
3619                                                      ext4_ext_pblock(ex));
3620                                err = ext4_ext_zeroout(inode, &zero_ex2);
3621                                if (err)
3622                                        goto out;
3623                        }
3624
3625                        split_map.m_len += split_map.m_lblk - ee_block;
3626                        split_map.m_lblk = ee_block;
3627                        allocated = map->m_len;
3628                }
3629        }
3630
3631        err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3632                                flags);
3633        if (err > 0)
3634                err = 0;
3635out:
3636        /* If we have gotten a failure, don't zero out status tree */
3637        if (!err) {
3638                err = ext4_zeroout_es(inode, &zero_ex1);
3639                if (!err)
3640                        err = ext4_zeroout_es(inode, &zero_ex2);
3641        }
3642        return err ? err : allocated;
3643}
3644
3645/*
3646 * This function is called by ext4_ext_map_blocks() from
3647 * ext4_get_blocks_dio_write() when DIO to write
3648 * to an unwritten extent.
3649 *
3650 * Writing to an unwritten extent may result in splitting the unwritten
3651 * extent into multiple initialized/unwritten extents (up to three)
3652 * There are three possibilities:
3653 *   a> There is no split required: Entire extent should be unwritten
3654 *   b> Splits in two extents: Write is happening at either end of the extent
3655 *   c> Splits in three extents: Somone is writing in middle of the extent
3656 *
3657 * This works the same way in the case of initialized -> unwritten conversion.
3658 *
3659 * One of more index blocks maybe needed if the extent tree grow after
3660 * the unwritten extent split. To prevent ENOSPC occur at the IO
3661 * complete, we need to split the unwritten extent before DIO submit
3662 * the IO. The unwritten extent called at this time will be split
3663 * into three unwritten extent(at most). After IO complete, the part
3664 * being filled will be convert to initialized by the end_io callback function
3665 * via ext4_convert_unwritten_extents().
3666 *
3667 * Returns the size of unwritten extent to be written on success.
3668 */
3669static int ext4_split_convert_extents(handle_t *handle,
3670                                        struct inode *inode,
3671                                        struct ext4_map_blocks *map,
3672                                        struct ext4_ext_path **ppath,
3673                                        int flags)
3674{
3675        struct ext4_ext_path *path = *ppath;
3676        ext4_lblk_t eof_block;
3677        ext4_lblk_t ee_block;
3678        struct ext4_extent *ex;
3679        unsigned int ee_len;
3680        int split_flag = 0, depth;
3681
3682        ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3683                  __func__, inode->i_ino,
3684                  (unsigned long long)map->m_lblk, map->m_len);
3685
3686        eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3687                inode->i_sb->s_blocksize_bits;
3688        if (eof_block < map->m_lblk + map->m_len)
3689                eof_block = map->m_lblk + map->m_len;
3690        /*
3691         * It is safe to convert extent to initialized via explicit
3692         * zeroout only if extent is fully insde i_size or new_size.
3693         */
3694        depth = ext_depth(inode);
3695        ex = path[depth].p_ext;
3696        ee_block = le32_to_cpu(ex->ee_block);
3697        ee_len = ext4_ext_get_actual_len(ex);
3698
3699        /* Convert to unwritten */
3700        if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3701                split_flag |= EXT4_EXT_DATA_VALID1;
3702        /* Convert to initialized */
3703        } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3704                split_flag |= ee_block + ee_len <= eof_block ?
3705                              EXT4_EXT_MAY_ZEROOUT : 0;
3706                split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3707        }
3708        flags |= EXT4_GET_BLOCKS_PRE_IO;
3709        return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3710}
3711
3712static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3713                                                struct inode *inode,
3714                                                struct ext4_map_blocks *map,
3715                                                struct ext4_ext_path **ppath)
3716{
3717        struct ext4_ext_path *path = *ppath;
3718        struct ext4_extent *ex;
3719        ext4_lblk_t ee_block;
3720        unsigned int ee_len;
3721        int depth;
3722        int err = 0;
3723
3724        depth = ext_depth(inode);
3725        ex = path[depth].p_ext;
3726        ee_block = le32_to_cpu(ex->ee_block);
3727        ee_len = ext4_ext_get_actual_len(ex);
3728
3729        ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3730                "block %llu, max_blocks %u\n", inode->i_ino,
3731                  (unsigned long long)ee_block, ee_len);
3732
3733        /* If extent is larger than requested it is a clear sign that we still
3734         * have some extent state machine issues left. So extent_split is still
3735         * required.
3736         * TODO: Once all related issues will be fixed this situation should be
3737         * illegal.
3738         */
3739        if (ee_block != map->m_lblk || ee_len > map->m_len) {
3740#ifdef EXT4_DEBUG
3741                ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3742                             " len %u; IO logical block %llu, len %u",
3743                             inode->i_ino, (unsigned long long)ee_block, ee_len,
3744                             (unsigned long long)map->m_lblk, map->m_len);
3745#endif
3746                err = ext4_split_convert_extents(handle, inode, map, ppath,
3747                                                 EXT4_GET_BLOCKS_CONVERT);
3748                if (err < 0)
3749                        return err;
3750                path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3751                if (IS_ERR(path))
3752                        return PTR_ERR(path);
3753                depth = ext_depth(inode);
3754                ex = path[depth].p_ext;
3755        }
3756
3757        err = ext4_ext_get_access(handle, inode, path + depth);
3758        if (err)
3759                goto out;
3760        /* first mark the extent as initialized */
3761        ext4_ext_mark_initialized(ex);
3762
3763        /* note: ext4_ext_correct_indexes() isn't needed here because
3764         * borders are not changed
3765         */
3766        ext4_ext_try_to_merge(handle, inode, path, ex);
3767
3768        /* Mark modified extent as dirty */
3769        err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3770out:
3771        ext4_ext_show_leaf(inode, path);
3772        return err;
3773}
3774
3775/*
3776 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3777 */
3778static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3779                              ext4_lblk_t lblk,
3780                              struct ext4_ext_path *path,
3781                              unsigned int len)
3782{
3783        int i, depth;
3784        struct ext4_extent_header *eh;
3785        struct ext4_extent *last_ex;
3786
3787        if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3788                return 0;
3789
3790        depth = ext_depth(inode);
3791        eh = path[depth].p_hdr;
3792
3793        /*
3794         * We're going to remove EOFBLOCKS_FL entirely in future so we
3795         * do not care for this case anymore. Simply remove the flag
3796         * if there are no extents.
3797         */
3798        if (unlikely(!eh->eh_entries))
3799                goto out;
3800        last_ex = EXT_LAST_EXTENT(eh);
3801        /*
3802         * We should clear the EOFBLOCKS_FL flag if we are writing the
3803         * last block in the last extent in the file.  We test this by
3804         * first checking to see if the caller to
3805         * ext4_ext_get_blocks() was interested in the last block (or
3806         * a block beyond the last block) in the current extent.  If
3807         * this turns out to be false, we can bail out from this
3808         * function immediately.
3809         */
3810        if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3811            ext4_ext_get_actual_len(last_ex))
3812                return 0;
3813        /*
3814         * If the caller does appear to be planning to write at or
3815         * beyond the end of the current extent, we then test to see
3816         * if the current extent is the last extent in the file, by
3817         * checking to make sure it was reached via the rightmost node
3818         * at each level of the tree.
3819         */
3820        for (i = depth-1; i >= 0; i--)
3821                if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3822                        return 0;
3823out:
3824        ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3825        return ext4_mark_inode_dirty(handle, inode);
3826}
3827
3828/**
3829 * ext4_find_delalloc_range: find delayed allocated block in the given range.
3830 *
3831 * Return 1 if there is a delalloc block in the range, otherwise 0.
3832 */
3833int ext4_find_delalloc_range(struct inode *inode,
3834                             ext4_lblk_t lblk_start,
3835                             ext4_lblk_t lblk_end)
3836{
3837        struct extent_status es;
3838
3839        ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3840        if (es.es_len == 0)
3841                return 0; /* there is no delay extent in this tree */
3842        else if (es.es_lblk <= lblk_start &&
3843                 lblk_start < es.es_lblk + es.es_len)
3844                return 1;
3845        else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3846                return 1;
3847        else
3848                return 0;
3849}
3850
3851int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3852{
3853        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3854        ext4_lblk_t lblk_start, lblk_end;
3855        lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3856        lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3857
3858        return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3859}
3860
3861/**
3862 * Determines how many complete clusters (out of those specified by the 'map')
3863 * are under delalloc and were reserved quota for.
3864 * This function is called when we are writing out the blocks that were
3865 * originally written with their allocation delayed, but then the space was
3866 * allocated using fallocate() before the delayed allocation could be resolved.
3867 * The cases to look for are:
3868 * ('=' indicated delayed allocated blocks
3869 *  '-' indicates non-delayed allocated blocks)
3870 * (a) partial clusters towards beginning and/or end outside of allocated range
3871 *     are not delalloc'ed.
3872 *      Ex:
3873 *      |----c---=|====c====|====c====|===-c----|
3874 *               |++++++ allocated ++++++|
3875 *      ==> 4 complete clusters in above example
3876 *
3877 * (b) partial cluster (outside of allocated range) towards either end is
3878 *     marked for delayed allocation. In this case, we will exclude that
3879 *     cluster.
3880 *      Ex:
3881 *      |----====c========|========c========|
3882 *           |++++++ allocated ++++++|
3883 *      ==> 1 complete clusters in above example
3884 *
3885 *      Ex:
3886 *      |================c================|
3887 *            |++++++ allocated ++++++|
3888 *      ==> 0 complete clusters in above example
3889 *
3890 * The ext4_da_update_reserve_space will be called only if we
3891 * determine here that there were some "entire" clusters that span
3892 * this 'allocated' range.
3893 * In the non-bigalloc case, this function will just end up returning num_blks
3894 * without ever calling ext4_find_delalloc_range.
3895 */
3896static unsigned int
3897get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3898                           unsigned int num_blks)
3899{
3900        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3901        ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3902        ext4_lblk_t lblk_from, lblk_to, c_offset;
3903        unsigned int allocated_clusters = 0;
3904
3905        alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3906        alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3907
3908        /* max possible clusters for this allocation */
3909        allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3910
3911        trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3912
3913        /* Check towards left side */
3914        c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3915        if (c_offset) {
3916                lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3917                lblk_to = lblk_from + c_offset - 1;
3918
3919                if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3920                        allocated_clusters--;
3921        }
3922
3923        /* Now check towards right. */
3924        c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3925        if (allocated_clusters && c_offset) {
3926                lblk_from = lblk_start + num_blks;
3927                lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3928
3929                if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3930                        allocated_clusters--;
3931        }
3932
3933        return allocated_clusters;
3934}
3935
3936static int
3937convert_initialized_extent(handle_t *handle, struct inode *inode,
3938                           struct ext4_map_blocks *map,
3939                           struct ext4_ext_path **ppath,
3940                           unsigned int allocated)
3941{
3942        struct ext4_ext_path *path = *ppath;
3943        struct ext4_extent *ex;
3944        ext4_lblk_t ee_block;
3945        unsigned int ee_len;
3946        int depth;
3947        int err = 0;
3948
3949        /*
3950         * Make sure that the extent is no bigger than we support with
3951         * unwritten extent
3952         */
3953        if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3954                map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3955
3956        depth = ext_depth(inode);
3957        ex = path[depth].p_ext;
3958        ee_block = le32_to_cpu(ex->ee_block);
3959        ee_len = ext4_ext_get_actual_len(ex);
3960
3961        ext_debug("%s: inode %lu, logical"
3962                "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3963                  (unsigned long long)ee_block, ee_len);
3964
3965        if (ee_block != map->m_lblk || ee_len > map->m_len) {
3966                err = ext4_split_convert_extents(handle, inode, map, ppath,
3967                                EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3968                if (err < 0)
3969                        return err;
3970                path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3971                if (IS_ERR(path))
3972                        return PTR_ERR(path);
3973                depth = ext_depth(inode);
3974                ex = path[depth].p_ext;
3975                if (!ex) {
3976                        EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3977                                         (unsigned long) map->m_lblk);
3978                        return -EFSCORRUPTED;
3979                }
3980        }
3981
3982        err = ext4_ext_get_access(handle, inode, path + depth);
3983        if (err)
3984                return err;
3985        /* first mark the extent as unwritten */
3986        ext4_ext_mark_unwritten(ex);
3987
3988        /* note: ext4_ext_correct_indexes() isn't needed here because
3989         * borders are not changed
3990         */
3991        ext4_ext_try_to_merge(handle, inode, path, ex);
3992
3993        /* Mark modified extent as dirty */
3994        err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3995        if (err)
3996                return err;
3997        ext4_ext_show_leaf(inode, path);
3998
3999        ext4_update_inode_fsync_trans(handle, inode, 1);
4000        err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
4001        if (err)
4002                return err;
4003        map->m_flags |= EXT4_MAP_UNWRITTEN;
4004        if (allocated > map->m_len)
4005                allocated = map->m_len;
4006        map->m_len = allocated;
4007        return allocated;
4008}
4009
4010static int
4011ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4012                        struct ext4_map_blocks *map,
4013                        struct ext4_ext_path **ppath, int flags,
4014                        unsigned int allocated, ext4_fsblk_t newblock)
4015{
4016        struct ext4_ext_path *path = *ppath;
4017        int ret = 0;
4018        int err = 0;
4019
4020        ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4021                  "block %llu, max_blocks %u, flags %x, allocated %u\n",
4022                  inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4023                  flags, allocated);
4024        ext4_ext_show_leaf(inode, path);
4025
4026        /*
4027         * When writing into unwritten space, we should not fail to
4028         * allocate metadata blocks for the new extent block if needed.
4029         */
4030        flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4031
4032        trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4033                                                    allocated, newblock);
4034
4035        /* get_block() before submit the IO, split the extent */
4036        if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4037                ret = ext4_split_convert_extents(handle, inode, map, ppath,
4038                                         flags | EXT4_GET_BLOCKS_CONVERT);
4039                if (ret <= 0)
4040                        goto out;
4041                map->m_flags |= EXT4_MAP_UNWRITTEN;
4042                goto out;
4043        }
4044        /* IO end_io complete, convert the filled extent to written */
4045        if (flags & EXT4_GET_BLOCKS_CONVERT) {
4046                if (flags & EXT4_GET_BLOCKS_ZERO) {
4047                        if (allocated > map->m_len)
4048                                allocated = map->m_len;
4049                        err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4050                                                 allocated);
4051                        if (err < 0)
4052                                goto out2;
4053                }
4054                ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4055                                                           ppath);
4056                if (ret >= 0) {
4057                        ext4_update_inode_fsync_trans(handle, inode, 1);
4058                        err = check_eofblocks_fl(handle, inode, map->m_lblk,
4059                                                 path, map->m_len);
4060                } else
4061                        err = ret;
4062                map->m_flags |= EXT4_MAP_MAPPED;
4063                map->m_pblk = newblock;
4064                if (allocated > map->m_len)
4065                        allocated = map->m_len;
4066                map->m_len = allocated;
4067                goto out2;
4068        }
4069        /* buffered IO case */
4070        /*
4071         * repeat fallocate creation request
4072         * we already have an unwritten extent
4073         */
4074        if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4075                map->m_flags |= EXT4_MAP_UNWRITTEN;
4076                goto map_out;
4077        }
4078
4079        /* buffered READ or buffered write_begin() lookup */
4080        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4081                /*
4082                 * We have blocks reserved already.  We
4083                 * return allocated blocks so that delalloc
4084                 * won't do block reservation for us.  But
4085                 * the buffer head will be unmapped so that
4086                 * a read from the block returns 0s.
4087                 */
4088                map->m_flags |= EXT4_MAP_UNWRITTEN;
4089                goto out1;
4090        }
4091
4092        /* buffered write, writepage time, convert*/
4093        ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4094        if (ret >= 0)
4095                ext4_update_inode_fsync_trans(handle, inode, 1);
4096out:
4097        if (ret <= 0) {
4098                err = ret;
4099                goto out2;
4100        } else
4101                allocated = ret;
4102        map->m_flags |= EXT4_MAP_NEW;
4103        /*
4104         * if we allocated more blocks than requested
4105         * we need to make sure we unmap the extra block
4106         * allocated. The actual needed block will get
4107         * unmapped later when we find the buffer_head marked
4108         * new.
4109         */
4110        if (allocated > map->m_len) {
4111                clean_bdev_aliases(inode->i_sb->s_bdev, newblock + map->m_len,
4112                                   allocated - map->m_len);
4113                allocated = map->m_len;
4114        }
4115        map->m_len = allocated;
4116
4117        /*
4118         * If we have done fallocate with the offset that is already
4119         * delayed allocated, we would have block reservation
4120         * and quota reservation done in the delayed write path.
4121         * But fallocate would have already updated quota and block
4122         * count for this offset. So cancel these reservation
4123         */
4124        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4125                unsigned int reserved_clusters;
4126                reserved_clusters = get_reserved_cluster_alloc(inode,
4127                                map->m_lblk, map->m_len);
4128                if (reserved_clusters)
4129                        ext4_da_update_reserve_space(inode,
4130                                                     reserved_clusters,
4131                                                     0);
4132        }
4133
4134map_out:
4135        map->m_flags |= EXT4_MAP_MAPPED;
4136        if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4137                err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4138                                         map->m_len);
4139                if (err < 0)
4140                        goto out2;
4141        }
4142out1:
4143        if (allocated > map->m_len)
4144                allocated = map->m_len;
4145        ext4_ext_show_leaf(inode, path);
4146        map->m_pblk = newblock;
4147        map->m_len = allocated;
4148out2:
4149        return err ? err : allocated;
4150}
4151
4152/*
4153 * get_implied_cluster_alloc - check to see if the requested
4154 * allocation (in the map structure) overlaps with a cluster already
4155 * allocated in an extent.
4156 *      @sb     The filesystem superblock structure
4157 *      @map    The requested lblk->pblk mapping
4158 *      @ex     The extent structure which might contain an implied
4159 *                      cluster allocation
4160 *
4161 * This function is called by ext4_ext_map_blocks() after we failed to
4162 * find blocks that were already in the inode's extent tree.  Hence,
4163 * we know that the beginning of the requested region cannot overlap
4164 * the extent from the inode's extent tree.  There are three cases we
4165 * want to catch.  The first is this case:
4166 *
4167 *               |--- cluster # N--|
4168 *    |--- extent ---|  |---- requested region ---|
4169 *                      |==========|
4170 *
4171 * The second case that we need to test for is this one:
4172 *
4173 *   |--------- cluster # N ----------------|
4174 *         |--- requested region --|   |------- extent ----|
4175 *         |=======================|
4176 *
4177 * The third case is when the requested region lies between two extents
4178 * within the same cluster:
4179 *          |------------- cluster # N-------------|
4180 * |----- ex -----|                  |---- ex_right ----|
4181 *                  |------ requested region ------|
4182 *                  |================|
4183 *
4184 * In each of the above cases, we need to set the map->m_pblk and
4185 * map->m_len so it corresponds to the return the extent labelled as
4186 * "|====|" from cluster #N, since it is already in use for data in
4187 * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4188 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4189 * as a new "allocated" block region.  Otherwise, we will return 0 and
4190 * ext4_ext_map_blocks() will then allocate one or more new clusters
4191 * by calling ext4_mb_new_blocks().
4192 */
4193static int get_implied_cluster_alloc(struct super_block *sb,
4194                                     struct ext4_map_blocks *map,
4195                                     struct ext4_extent *ex,
4196                                     struct ext4_ext_path *path)
4197{
4198        struct ext4_sb_info *sbi = EXT4_SB(sb);
4199        ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4200        ext4_lblk_t ex_cluster_start, ex_cluster_end;
4201        ext4_lblk_t rr_cluster_start;
4202        ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4203        ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4204        unsigned short ee_len = ext4_ext_get_actual_len(ex);
4205
4206        /* The extent passed in that we are trying to match */
4207        ex_cluster_start = EXT4_B2C(sbi, ee_block);
4208        ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4209
4210        /* The requested region passed into ext4_map_blocks() */
4211        rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4212
4213        if ((rr_cluster_start == ex_cluster_end) ||
4214            (rr_cluster_start == ex_cluster_start)) {
4215                if (rr_cluster_start == ex_cluster_end)
4216                        ee_start += ee_len - 1;
4217                map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4218                map->m_len = min(map->m_len,
4219                                 (unsigned) sbi->s_cluster_ratio - c_offset);
4220                /*
4221                 * Check for and handle this case:
4222                 *
4223                 *   |--------- cluster # N-------------|
4224                 *                     |------- extent ----|
4225                 *         |--- requested region ---|
4226                 *         |===========|
4227                 */
4228
4229                if (map->m_lblk < ee_block)
4230                        map->m_len = min(map->m_len, ee_block - map->m_lblk);
4231
4232                /*
4233                 * Check for the case where there is already another allocated
4234                 * block to the right of 'ex' but before the end of the cluster.
4235                 *
4236                 *          |------------- cluster # N-------------|
4237                 * |----- ex -----|                  |---- ex_right ----|
4238                 *                  |------ requested region ------|
4239                 *                  |================|
4240                 */
4241                if (map->m_lblk > ee_block) {
4242                        ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4243                        map->m_len = min(map->m_len, next - map->m_lblk);
4244                }
4245
4246                trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4247                return 1;
4248        }
4249
4250        trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4251        return 0;
4252}
4253
4254
4255/*
4256 * Block allocation/map/preallocation routine for extents based files
4257 *
4258 *
4259 * Need to be called with
4260 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4261 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4262 *
4263 * return > 0, number of of blocks already mapped/allocated
4264 *          if create == 0 and these are pre-allocated blocks
4265 *              buffer head is unmapped
4266 *          otherwise blocks are mapped
4267 *
4268 * return = 0, if plain look up failed (blocks have not been allocated)
4269 *          buffer head is unmapped
4270 *
4271 * return < 0, error case.
4272 */
4273int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4274                        struct ext4_map_blocks *map, int flags)
4275{
4276        struct ext4_ext_path *path = NULL;
4277        struct ext4_extent newex, *ex, *ex2;
4278        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4279        ext4_fsblk_t newblock = 0;
4280        int free_on_err = 0, err = 0, depth, ret;
4281        unsigned int allocated = 0, offset = 0;
4282        unsigned int allocated_clusters = 0;
4283        struct ext4_allocation_request ar;
4284        ext4_lblk_t cluster_offset;
4285        bool map_from_cluster = false;
4286
4287        ext_debug("blocks %u/%u requested for inode %lu\n",
4288                  map->m_lblk, map->m_len, inode->i_ino);
4289        trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4290
4291        /* find extent for this block */
4292        path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4293        if (IS_ERR(path)) {
4294                err = PTR_ERR(path);
4295                path = NULL;
4296                goto out2;
4297        }
4298
4299        depth = ext_depth(inode);
4300
4301        /*
4302         * consistent leaf must not be empty;
4303         * this situation is possible, though, _during_ tree modification;
4304         * this is why assert can't be put in ext4_find_extent()
4305         */
4306        if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4307                EXT4_ERROR_INODE(inode, "bad extent address "
4308                                 "lblock: %lu, depth: %d pblock %lld",
4309                                 (unsigned long) map->m_lblk, depth,
4310                                 path[depth].p_block);
4311                err = -EFSCORRUPTED;
4312                goto out2;
4313        }
4314
4315        ex = path[depth].p_ext;
4316        if (ex) {
4317                ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4318                ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4319                unsigned short ee_len;
4320
4321
4322                /*
4323                 * unwritten extents are treated as holes, except that
4324                 * we split out initialized portions during a write.
4325                 */
4326                ee_len = ext4_ext_get_actual_len(ex);
4327
4328                trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4329
4330                /* if found extent covers block, simply return it */
4331                if (in_range(map->m_lblk, ee_block, ee_len)) {
4332                        newblock = map->m_lblk - ee_block + ee_start;
4333                        /* number of remaining blocks in the extent */
4334                        allocated = ee_len - (map->m_lblk - ee_block);
4335                        ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4336                                  ee_block, ee_len, newblock);
4337
4338                        /*
4339                         * If the extent is initialized check whether the
4340                         * caller wants to convert it to unwritten.
4341                         */
4342                        if ((!ext4_ext_is_unwritten(ex)) &&
4343                            (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4344                                allocated = convert_initialized_extent(
4345                                                handle, inode, map, &path,
4346                                                allocated);
4347                                goto out2;
4348                        } else if (!ext4_ext_is_unwritten(ex))
4349                                goto out;
4350
4351                        ret = ext4_ext_handle_unwritten_extents(
4352                                handle, inode, map, &path, flags,
4353                                allocated, newblock);
4354                        if (ret < 0)
4355                                err = ret;
4356                        else
4357                                allocated = ret;
4358                        goto out2;
4359                }
4360        }
4361
4362        /*
4363         * requested block isn't allocated yet;
4364         * we couldn't try to create block if create flag is zero
4365         */
4366        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4367                ext4_lblk_t hole_start, hole_len;
4368
4369                hole_start = map->m_lblk;
4370                hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4371                /*
4372                 * put just found gap into cache to speed up
4373                 * subsequent requests
4374                 */
4375                ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4376
4377                /* Update hole_len to reflect hole size after map->m_lblk */
4378                if (hole_start != map->m_lblk)
4379                        hole_len -= map->m_lblk - hole_start;
4380                map->m_pblk = 0;
4381                map->m_len = min_t(unsigned int, map->m_len, hole_len);
4382
4383                goto out2;
4384        }
4385
4386        /*
4387         * Okay, we need to do block allocation.
4388         */
4389        newex.ee_block = cpu_to_le32(map->m_lblk);
4390        cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4391
4392        /*
4393         * If we are doing bigalloc, check to see if the extent returned
4394         * by ext4_find_extent() implies a cluster we can use.
4395         */
4396        if (cluster_offset && ex &&
4397            get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4398                ar.len = allocated = map->m_len;
4399                newblock = map->m_pblk;
4400                map_from_cluster = true;
4401                goto got_allocated_blocks;
4402        }
4403
4404        /* find neighbour allocated blocks */
4405        ar.lleft = map->m_lblk;
4406        err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4407        if (err)
4408                goto out2;
4409        ar.lright = map->m_lblk;
4410        ex2 = NULL;
4411        err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4412        if (err)
4413                goto out2;
4414
4415        /* Check if the extent after searching to the right implies a
4416         * cluster we can use. */
4417        if ((sbi->s_cluster_ratio > 1) && ex2 &&
4418            get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4419                ar.len = allocated = map->m_len;
4420                newblock = map->m_pblk;
4421                map_from_cluster = true;
4422                goto got_allocated_blocks;
4423        }
4424
4425        /*
4426         * See if request is beyond maximum number of blocks we can have in
4427         * a single extent. For an initialized extent this limit is
4428         * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4429         * EXT_UNWRITTEN_MAX_LEN.
4430         */
4431        if (map->m_len > EXT_INIT_MAX_LEN &&
4432            !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4433                map->m_len = EXT_INIT_MAX_LEN;
4434        else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4435                 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4436                map->m_len = EXT_UNWRITTEN_MAX_LEN;
4437
4438        /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4439        newex.ee_len = cpu_to_le16(map->m_len);
4440        err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4441        if (err)
4442                allocated = ext4_ext_get_actual_len(&newex);
4443        else
4444                allocated = map->m_len;
4445
4446        /* allocate new block */
4447        ar.inode = inode;
4448        ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4449        ar.logical = map->m_lblk;
4450        /*
4451         * We calculate the offset from the beginning of the cluster
4452         * for the logical block number, since when we allocate a
4453         * physical cluster, the physical block should start at the
4454         * same offset from the beginning of the cluster.  This is
4455         * needed so that future calls to get_implied_cluster_alloc()
4456         * work correctly.
4457         */
4458        offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4459        ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4460        ar.goal -= offset;
4461        ar.logical -= offset;
4462        if (S_ISREG(inode->i_mode))
4463                ar.flags = EXT4_MB_HINT_DATA;
4464        else
4465                /* disable in-core preallocation for non-regular files */
4466                ar.flags = 0;
4467        if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4468                ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4469        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4470                ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4471        if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4472                ar.flags |= EXT4_MB_USE_RESERVED;
4473        newblock = ext4_mb_new_blocks(handle, &ar, &err);
4474        if (!newblock)
4475                goto out2;
4476        ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4477                  ar.goal, newblock, allocated);
4478        free_on_err = 1;
4479        allocated_clusters = ar.len;
4480        ar.len = EXT4_C2B(sbi, ar.len) - offset;
4481        if (ar.len > allocated)
4482                ar.len = allocated;
4483
4484got_allocated_blocks:
4485        /* try to insert new extent into found leaf and return */
4486        ext4_ext_store_pblock(&newex, newblock + offset);
4487        newex.ee_len = cpu_to_le16(ar.len);
4488        /* Mark unwritten */
4489        if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4490                ext4_ext_mark_unwritten(&newex);
4491                map->m_flags |= EXT4_MAP_UNWRITTEN;
4492        }
4493
4494        err = 0;
4495        if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4496                err = check_eofblocks_fl(handle, inode, map->m_lblk,
4497                                         path, ar.len);
4498        if (!err)
4499                err = ext4_ext_insert_extent(handle, inode, &path,
4500                                             &newex, flags);
4501
4502        if (err && free_on_err) {
4503                int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4504                        EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4505                /* free data blocks we just allocated */
4506                /* not a good idea to call discard here directly,
4507                 * but otherwise we'd need to call it every free() */
4508                ext4_discard_preallocations(inode);
4509                ext4_free_blocks(handle, inode, NULL, newblock,
4510                                 EXT4_C2B(sbi, allocated_clusters), fb_flags);
4511                goto out2;
4512        }
4513
4514        /* previous routine could use block we allocated */
4515        newblock = ext4_ext_pblock(&newex);
4516        allocated = ext4_ext_get_actual_len(&newex);
4517        if (allocated > map->m_len)
4518                allocated = map->m_len;
4519        map->m_flags |= EXT4_MAP_NEW;
4520
4521        /*
4522         * Update reserved blocks/metadata blocks after successful
4523         * block allocation which had been deferred till now.
4524         */
4525        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4526                unsigned int reserved_clusters;
4527                /*
4528                 * Check how many clusters we had reserved this allocated range
4529                 */
4530                reserved_clusters = get_reserved_cluster_alloc(inode,
4531                                                map->m_lblk, allocated);
4532                if (!map_from_cluster) {
4533                        BUG_ON(allocated_clusters < reserved_clusters);
4534                        if (reserved_clusters < allocated_clusters) {
4535                                struct ext4_inode_info *ei = EXT4_I(inode);
4536                                int reservation = allocated_clusters -
4537                                                  reserved_clusters;
4538                                /*
4539                                 * It seems we claimed few clusters outside of
4540                                 * the range of this allocation. We should give
4541                                 * it back to the reservation pool. This can
4542                                 * happen in the following case:
4543                                 *
4544                                 * * Suppose s_cluster_ratio is 4 (i.e., each
4545                                 *   cluster has 4 blocks. Thus, the clusters
4546                                 *   are [0-3],[4-7],[8-11]...
4547                                 * * First comes delayed allocation write for
4548                                 *   logical blocks 10 & 11. Since there were no
4549                                 *   previous delayed allocated blocks in the
4550                                 *   range [8-11], we would reserve 1 cluster
4551                                 *   for this write.
4552                                 * * Next comes write for logical blocks 3 to 8.
4553                                 *   In this case, we will reserve 2 clusters
4554                                 *   (for [0-3] and [4-7]; and not for [8-11] as
4555                                 *   that range has a delayed allocated blocks.
4556                                 *   Thus total reserved clusters now becomes 3.
4557                                 * * Now, during the delayed allocation writeout
4558                                 *   time, we will first write blocks [3-8] and
4559                                 *   allocate 3 clusters for writing these
4560                                 *   blocks. Also, we would claim all these
4561                                 *   three clusters above.
4562                                 * * Now when we come here to writeout the
4563                                 *   blocks [10-11], we would expect to claim
4564                                 *   the reservation of 1 cluster we had made
4565                                 *   (and we would claim it since there are no
4566                                 *   more delayed allocated blocks in the range
4567                                 *   [8-11]. But our reserved cluster count had
4568                                 *   already gone to 0.
4569                                 *
4570                                 *   Thus, at the step 4 above when we determine
4571                                 *   that there are still some unwritten delayed
4572                                 *   allocated blocks outside of our current
4573                                 *   block range, we should increment the
4574                                 *   reserved clusters count so that when the
4575                                 *   remaining blocks finally gets written, we
4576                                 *   could claim them.
4577                                 */
4578                                dquot_reserve_block(inode,
4579                                                EXT4_C2B(sbi, reservation));
4580                                spin_lock(&ei->i_block_reservation_lock);
4581                                ei->i_reserved_data_blocks += reservation;
4582                                spin_unlock(&ei->i_block_reservation_lock);
4583                        }
4584                        /*
4585                         * We will claim quota for all newly allocated blocks.
4586                         * We're updating the reserved space *after* the
4587                         * correction above so we do not accidentally free
4588                         * all the metadata reservation because we might
4589                         * actually need it later on.
4590                         */
4591                        ext4_da_update_reserve_space(inode, allocated_clusters,
4592                                                        1);
4593                }
4594        }
4595
4596        /*
4597         * Cache the extent and update transaction to commit on fdatasync only
4598         * when it is _not_ an unwritten extent.
4599         */
4600        if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4601                ext4_update_inode_fsync_trans(handle, inode, 1);
4602        else
4603                ext4_update_inode_fsync_trans(handle, inode, 0);
4604out:
4605        if (allocated > map->m_len)
4606                allocated = map->m_len;
4607        ext4_ext_show_leaf(inode, path);
4608        map->m_flags |= EXT4_MAP_MAPPED;
4609        map->m_pblk = newblock;
4610        map->m_len = allocated;
4611out2:
4612        ext4_ext_drop_refs(path);
4613        kfree(path);
4614
4615        trace_ext4_ext_map_blocks_exit(inode, flags, map,
4616                                       err ? err : allocated);
4617        return err ? err : allocated;
4618}
4619
4620int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4621{
4622        struct super_block *sb = inode->i_sb;
4623        ext4_lblk_t last_block;
4624        int err = 0;
4625
4626        /*
4627         * TODO: optimization is possible here.
4628         * Probably we need not scan at all,
4629         * because page truncation is enough.
4630         */
4631
4632        /* we have to know where to truncate from in crash case */
4633        EXT4_I(inode)->i_disksize = inode->i_size;
4634        err = ext4_mark_inode_dirty(handle, inode);
4635        if (err)
4636                return err;
4637
4638        last_block = (inode->i_size + sb->s_blocksize - 1)
4639                        >> EXT4_BLOCK_SIZE_BITS(sb);
4640retry:
4641        err = ext4_es_remove_extent(inode, last_block,
4642                                    EXT_MAX_BLOCKS - last_block);
4643        if (err == -ENOMEM) {
4644                cond_resched();
4645                congestion_wait(BLK_RW_ASYNC, HZ/50);
4646                goto retry;
4647        }
4648        if (err)
4649                return err;
4650        return ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4651}
4652
4653static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4654                                  ext4_lblk_t len, loff_t new_size,
4655                                  int flags)
4656{
4657        struct inode *inode = file_inode(file);
4658        handle_t *handle;
4659        int ret = 0;
4660        int ret2 = 0;
4661        int retries = 0;
4662        int depth = 0;
4663        struct ext4_map_blocks map;
4664        unsigned int credits;
4665        loff_t epos;
4666
4667        BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4668        map.m_lblk = offset;
4669        map.m_len = len;
4670        /*
4671         * Don't normalize the request if it can fit in one extent so
4672         * that it doesn't get unnecessarily split into multiple
4673         * extents.
4674         */
4675        if (len <= EXT_UNWRITTEN_MAX_LEN)
4676                flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4677
4678        /*
4679         * credits to insert 1 extent into extent tree
4680         */
4681        credits = ext4_chunk_trans_blocks(inode, len);
4682        depth = ext_depth(inode);
4683
4684retry:
4685        while (ret >= 0 && len) {
4686                /*
4687                 * Recalculate credits when extent tree depth changes.
4688                 */
4689                if (depth != ext_depth(inode)) {
4690                        credits = ext4_chunk_trans_blocks(inode, len);
4691                        depth = ext_depth(inode);
4692                }
4693
4694                handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4695                                            credits);
4696                if (IS_ERR(handle)) {
4697                        ret = PTR_ERR(handle);
4698                        break;
4699                }
4700                ret = ext4_map_blocks(handle, inode, &map, flags);
4701                if (ret <= 0) {
4702                        ext4_debug("inode #%lu: block %u: len %u: "
4703                                   "ext4_ext_map_blocks returned %d",
4704                                   inode->i_ino, map.m_lblk,
4705                                   map.m_len, ret);
4706                        ext4_mark_inode_dirty(handle, inode);
4707                        ret2 = ext4_journal_stop(handle);
4708                        break;
4709                }
4710                map.m_lblk += ret;
4711                map.m_len = len = len - ret;
4712                epos = (loff_t)map.m_lblk << inode->i_blkbits;
4713                inode->i_ctime = current_time(inode);
4714                if (new_size) {
4715                        if (epos > new_size)
4716                                epos = new_size;
4717                        if (ext4_update_inode_size(inode, epos) & 0x1)
4718                                inode->i_mtime = inode->i_ctime;
4719                } else {
4720                        if (epos > inode->i_size)
4721                                ext4_set_inode_flag(inode,
4722                                                    EXT4_INODE_EOFBLOCKS);
4723                }
4724                ext4_mark_inode_dirty(handle, inode);
4725                ret2 = ext4_journal_stop(handle);
4726                if (ret2)
4727                        break;
4728        }
4729        if (ret == -ENOSPC &&
4730                        ext4_should_retry_alloc(inode->i_sb, &retries)) {
4731                ret = 0;
4732                goto retry;
4733        }
4734
4735        return ret > 0 ? ret2 : ret;
4736}
4737
4738static long ext4_zero_range(struct file *file, loff_t offset,
4739                            loff_t len, int mode)
4740{
4741        struct inode *inode = file_inode(file);
4742        handle_t *handle = NULL;
4743        unsigned int max_blocks;
4744        loff_t new_size = 0;
4745        int ret = 0;
4746        int flags;
4747        int credits;
4748        int partial_begin, partial_end;
4749        loff_t start, end;
4750        ext4_lblk_t lblk;
4751        unsigned int blkbits = inode->i_blkbits;
4752
4753        trace_ext4_zero_range(inode, offset, len, mode);
4754
4755        if (!S_ISREG(inode->i_mode))
4756                return -EINVAL;
4757
4758        /* Call ext4_force_commit to flush all data in case of data=journal. */
4759        if (ext4_should_journal_data(inode)) {
4760                ret = ext4_force_commit(inode->i_sb);
4761                if (ret)
4762                        return ret;
4763        }
4764
4765        /*
4766         * Round up offset. This is not fallocate, we neet to zero out
4767         * blocks, so convert interior block aligned part of the range to
4768         * unwritten and possibly manually zero out unaligned parts of the
4769         * range.
4770         */
4771        start = round_up(offset, 1 << blkbits);
4772        end = round_down((offset + len), 1 << blkbits);
4773
4774        if (start < offset || end > offset + len)
4775                return -EINVAL;
4776        partial_begin = offset & ((1 << blkbits) - 1);
4777        partial_end = (offset + len) & ((1 << blkbits) - 1);
4778
4779        lblk = start >> blkbits;
4780        max_blocks = (end >> blkbits);
4781        if (max_blocks < lblk)
4782                max_blocks = 0;
4783        else
4784                max_blocks -= lblk;
4785
4786        inode_lock(inode);
4787
4788        /*
4789         * Indirect files do not support unwritten extnets
4790         */
4791        if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4792                ret = -EOPNOTSUPP;
4793                goto out_mutex;
4794        }
4795
4796        if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4797             offset + len > i_size_read(inode)) {
4798                new_size = offset + len;
4799                ret = inode_newsize_ok(inode, new_size);
4800                if (ret)
4801                        goto out_mutex;
4802        }
4803
4804        flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4805        if (mode & FALLOC_FL_KEEP_SIZE)
4806                flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4807
4808        /* Wait all existing dio workers, newcomers will block on i_mutex */
4809        ext4_inode_block_unlocked_dio(inode);
4810        inode_dio_wait(inode);
4811
4812        /* Preallocate the range including the unaligned edges */
4813        if (partial_begin || partial_end) {
4814                ret = ext4_alloc_file_blocks(file,
4815                                round_down(offset, 1 << blkbits) >> blkbits,
4816                                (round_up((offset + len), 1 << blkbits) -
4817                                 round_down(offset, 1 << blkbits)) >> blkbits,
4818                                new_size, flags);
4819                if (ret)
4820                        goto out_dio;
4821
4822        }
4823
4824        /* Zero range excluding the unaligned edges */
4825        if (max_blocks > 0) {
4826                flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4827                          EXT4_EX_NOCACHE);
4828
4829                /*
4830                 * Prevent page faults from reinstantiating pages we have
4831                 * released from page cache.
4832                 */
4833                down_write(&EXT4_I(inode)->i_mmap_sem);
4834                ret = ext4_update_disksize_before_punch(inode, offset, len);
4835                if (ret) {
4836                        up_write(&EXT4_I(inode)->i_mmap_sem);
4837                        goto out_dio;
4838                }
4839                /* Now release the pages and zero block aligned part of pages */
4840                truncate_pagecache_range(inode, start, end - 1);
4841                inode->i_mtime = inode->i_ctime = current_time(inode);
4842
4843                ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4844                                             flags);
4845                up_write(&EXT4_I(inode)->i_mmap_sem);
4846                if (ret)
4847                        goto out_dio;
4848        }
4849        if (!partial_begin && !partial_end)
4850                goto out_dio;
4851
4852        /*
4853         * In worst case we have to writeout two nonadjacent unwritten
4854         * blocks and update the inode
4855         */
4856        credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4857        if (ext4_should_journal_data(inode))
4858                credits += 2;
4859        handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4860        if (IS_ERR(handle)) {
4861                ret = PTR_ERR(handle);
4862                ext4_std_error(inode->i_sb, ret);
4863                goto out_dio;
4864        }
4865
4866        inode->i_mtime = inode->i_ctime = current_time(inode);
4867        if (new_size) {
4868                ext4_update_inode_size(inode, new_size);
4869        } else {
4870                /*
4871                * Mark that we allocate beyond EOF so the subsequent truncate
4872                * can proceed even if the new size is the same as i_size.
4873                */
4874                if ((offset + len) > i_size_read(inode))
4875                        ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4876        }
4877        ext4_mark_inode_dirty(handle, inode);
4878
4879        /* Zero out partial block at the edges of the range */
4880        ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4881        if (ret >= 0)
4882                ext4_update_inode_fsync_trans(handle, inode, 1);
4883
4884        if (file->f_flags & O_SYNC)
4885                ext4_handle_sync(handle);
4886
4887        ext4_journal_stop(handle);
4888out_dio:
4889        ext4_inode_resume_unlocked_dio(inode);
4890out_mutex:
4891        inode_unlock(inode);
4892        return ret;
4893}
4894
4895/*
4896 * preallocate space for a file. This implements ext4's fallocate file
4897 * operation, which gets called from sys_fallocate system call.
4898 * For block-mapped files, posix_fallocate should fall back to the method
4899 * of writing zeroes to the required new blocks (the same behavior which is
4900 * expected for file systems which do not support fallocate() system call).
4901 */
4902long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4903{
4904        struct inode *inode = file_inode(file);
4905        loff_t new_size = 0;
4906        unsigned int max_blocks;
4907        int ret = 0;
4908        int flags;
4909        ext4_lblk_t lblk;
4910        unsigned int blkbits = inode->i_blkbits;
4911
4912        /*
4913         * Encrypted inodes can't handle collapse range or insert
4914         * range since we would need to re-encrypt blocks with a
4915         * different IV or XTS tweak (which are based on the logical
4916         * block number).
4917         *
4918         * XXX It's not clear why zero range isn't working, but we'll
4919         * leave it disabled for encrypted inodes for now.  This is a
4920         * bug we should fix....
4921         */
4922        if (ext4_encrypted_inode(inode) &&
4923            (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4924                     FALLOC_FL_ZERO_RANGE)))
4925                return -EOPNOTSUPP;
4926
4927        /* Return error if mode is not supported */
4928        if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4929                     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4930                     FALLOC_FL_INSERT_RANGE))
4931                return -EOPNOTSUPP;
4932
4933        if (mode & FALLOC_FL_PUNCH_HOLE)
4934                return ext4_punch_hole(inode, offset, len);
4935
4936        ret = ext4_convert_inline_data(inode);
4937        if (ret)
4938                return ret;
4939
4940        if (mode & FALLOC_FL_COLLAPSE_RANGE)
4941                return ext4_collapse_range(inode, offset, len);
4942
4943        if (mode & FALLOC_FL_INSERT_RANGE)
4944                return ext4_insert_range(inode, offset, len);
4945
4946        if (mode & FALLOC_FL_ZERO_RANGE)
4947                return ext4_zero_range(file, offset, len, mode);
4948
4949        trace_ext4_fallocate_enter(inode, offset, len, mode);
4950        lblk = offset >> blkbits;
4951
4952        max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4953        flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4954        if (mode & FALLOC_FL_KEEP_SIZE)
4955                flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4956
4957        inode_lock(inode);
4958
4959        /*
4960         * We only support preallocation for extent-based files only
4961         */
4962        if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4963                ret = -EOPNOTSUPP;
4964                goto out;
4965        }
4966
4967        if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4968             offset + len > i_size_read(inode)) {
4969                new_size = offset + len;
4970                ret = inode_newsize_ok(inode, new_size);
4971                if (ret)
4972                        goto out;
4973        }
4974
4975        /* Wait all existing dio workers, newcomers will block on i_mutex */
4976        ext4_inode_block_unlocked_dio(inode);
4977        inode_dio_wait(inode);
4978
4979        ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4980        ext4_inode_resume_unlocked_dio(inode);
4981        if (ret)
4982                goto out;
4983
4984        if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4985                ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
4986                                                EXT4_I(inode)->i_sync_tid);
4987        }
4988out:
4989        inode_unlock(inode);
4990        trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4991        return ret;
4992}
4993
4994/*
4995 * This function convert a range of blocks to written extents
4996 * The caller of this function will pass the start offset and the size.
4997 * all unwritten extents within this range will be converted to
4998 * written extents.
4999 *
5000 * This function is called from the direct IO end io call back
5001 * function, to convert the fallocated extents after IO is completed.
5002 * Returns 0 on success.
5003 */
5004int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
5005                                   loff_t offset, ssize_t len)
5006{
5007        unsigned int max_blocks;
5008        int ret = 0;
5009        int ret2 = 0;
5010        struct ext4_map_blocks map;
5011        unsigned int credits, blkbits = inode->i_blkbits;
5012
5013        map.m_lblk = offset >> blkbits;
5014        max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
5015
5016        /*
5017         * This is somewhat ugly but the idea is clear: When transaction is
5018         * reserved, everything goes into it. Otherwise we rather start several
5019         * smaller transactions for conversion of each extent separately.
5020         */
5021        if (handle) {
5022                handle = ext4_journal_start_reserved(handle,
5023                                                     EXT4_HT_EXT_CONVERT);
5024                if (IS_ERR(handle))
5025                        return PTR_ERR(handle);
5026                credits = 0;
5027        } else {
5028                /*
5029                 * credits to insert 1 extent into extent tree
5030                 */
5031                credits = ext4_chunk_trans_blocks(inode, max_blocks);
5032        }
5033        while (ret >= 0 && ret < max_blocks) {
5034                map.m_lblk += ret;
5035                map.m_len = (max_blocks -= ret);
5036                if (credits) {
5037                        handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5038                                                    credits);
5039                        if (IS_ERR(handle)) {
5040                                ret = PTR_ERR(handle);
5041                                break;
5042                        }
5043                }
5044                ret = ext4_map_blocks(handle, inode, &map,
5045                                      EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5046                if (ret <= 0)
5047                        ext4_warning(inode->i_sb,
5048                                     "inode #%lu: block %u: len %u: "
5049                                     "ext4_ext_map_blocks returned %d",
5050                                     inode->i_ino, map.m_lblk,
5051                                     map.m_len, ret);
5052                ext4_mark_inode_dirty(handle, inode);
5053                if (credits)
5054                        ret2 = ext4_journal_stop(handle);
5055                if (ret <= 0 || ret2)
5056                        break;
5057        }
5058        if (!credits)
5059                ret2 = ext4_journal_stop(handle);
5060        return ret > 0 ? ret2 : ret;
5061}
5062
5063/*
5064 * If newes is not existing extent (newes->ec_pblk equals zero) find
5065 * delayed extent at start of newes and update newes accordingly and
5066 * return start of the next delayed extent.
5067 *
5068 * If newes is existing extent (newes->ec_pblk is not equal zero)
5069 * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5070 * extent found. Leave newes unmodified.
5071 */
5072static int ext4_find_delayed_extent(struct inode *inode,
5073                                    struct extent_status *newes)
5074{
5075        struct extent_status es;
5076        ext4_lblk_t block, next_del;
5077
5078        if (newes->es_pblk == 0) {
5079                ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5080                                newes->es_lblk + newes->es_len - 1, &es);
5081
5082                /*
5083                 * No extent in extent-tree contains block @newes->es_pblk,
5084                 * then the block may stay in 1)a hole or 2)delayed-extent.
5085                 */
5086                if (es.es_len == 0)
5087                        /* A hole found. */
5088                        return 0;
5089
5090                if (es.es_lblk > newes->es_lblk) {
5091                        /* A hole found. */
5092                        newes->es_len = min(es.es_lblk - newes->es_lblk,
5093                                            newes->es_len);
5094                        return 0;
5095                }
5096
5097                newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5098        }
5099
5100        block = newes->es_lblk + newes->es_len;
5101        ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5102        if (es.es_len == 0)
5103                next_del = EXT_MAX_BLOCKS;
5104        else
5105                next_del = es.es_lblk;
5106
5107        return next_del;
5108}
5109/* fiemap flags we can handle specified here */
5110#define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5111
5112static int ext4_xattr_fiemap(struct inode *inode,
5113                                struct fiemap_extent_info *fieinfo)
5114{
5115        __u64 physical = 0;
5116        __u64 length;
5117        __u32 flags = FIEMAP_EXTENT_LAST;
5118        int blockbits = inode->i_sb->s_blocksize_bits;
5119        int error = 0;
5120
5121        /* in-inode? */
5122        if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5123                struct ext4_iloc iloc;
5124                int offset;     /* offset of xattr in inode */
5125
5126                error = ext4_get_inode_loc(inode, &iloc);
5127                if (error)
5128                        return error;
5129                physical = (__u64)iloc.bh->b_blocknr << blockbits;
5130                offset = EXT4_GOOD_OLD_INODE_SIZE +
5131                                EXT4_I(inode)->i_extra_isize;
5132                physical += offset;
5133                length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5134                flags |= FIEMAP_EXTENT_DATA_INLINE;
5135                brelse(iloc.bh);
5136        } else { /* external block */
5137                physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5138                length = inode->i_sb->s_blocksize;
5139        }
5140
5141        if (physical)
5142                error = fiemap_fill_next_extent(fieinfo, 0, physical,
5143                                                length, flags);
5144        return (error < 0 ? error : 0);
5145}
5146
5147int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5148                __u64 start, __u64 len)
5149{
5150        ext4_lblk_t start_blk;
5151        int error = 0;
5152
5153        if (ext4_has_inline_data(inode)) {
5154                int has_inline = 1;
5155
5156                error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5157                                                start, len);
5158
5159                if (has_inline)
5160                        return error;
5161        }
5162
5163        if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5164                error = ext4_ext_precache(inode);
5165                if (error)
5166                        return error;
5167        }
5168
5169        /* fallback to generic here if not in extents fmt */
5170        if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5171                return generic_block_fiemap(inode, fieinfo, start, len,
5172                        ext4_get_block);
5173
5174        if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5175                return -EBADR;
5176
5177        if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5178                error = ext4_xattr_fiemap(inode, fieinfo);
5179        } else {
5180                ext4_lblk_t len_blks;
5181                __u64 last_blk;
5182
5183                start_blk = start >> inode->i_sb->s_blocksize_bits;
5184                last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5185                if (last_blk >= EXT_MAX_BLOCKS)
5186                        last_blk = EXT_MAX_BLOCKS-1;
5187                len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5188
5189                /*
5190                 * Walk the extent tree gathering extent information
5191                 * and pushing extents back to the user.
5192                 */
5193                error = ext4_fill_fiemap_extents(inode, start_blk,
5194                                                 len_blks, fieinfo);
5195        }
5196        return error;
5197}
5198
5199/*
5200 * ext4_access_path:
5201 * Function to access the path buffer for marking it dirty.
5202 * It also checks if there are sufficient credits left in the journal handle
5203 * to update path.
5204 */
5205static int
5206ext4_access_path(handle_t *handle, struct inode *inode,
5207                struct ext4_ext_path *path)
5208{
5209        int credits, err;
5210
5211        if (!ext4_handle_valid(handle))
5212                return 0;
5213
5214        /*
5215         * Check if need to extend journal credits
5216         * 3 for leaf, sb, and inode plus 2 (bmap and group
5217         * descriptor) for each block group; assume two block
5218         * groups
5219         */
5220        if (handle->h_buffer_credits < 7) {
5221                credits = ext4_writepage_trans_blocks(inode);
5222                err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5223                /* EAGAIN is success */
5224                if (err && err != -EAGAIN)
5225                        return err;
5226        }
5227
5228        err = ext4_ext_get_access(handle, inode, path);
5229        return err;
5230}
5231
5232/*
5233 * ext4_ext_shift_path_extents:
5234 * Shift the extents of a path structure lying between path[depth].p_ext
5235 * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5236 * if it is right shift or left shift operation.
5237 */
5238static int
5239ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5240                            struct inode *inode, handle_t *handle,
5241                            enum SHIFT_DIRECTION SHIFT)
5242{
5243        int depth, err = 0;
5244        struct ext4_extent *ex_start, *ex_last;
5245        bool update = 0;
5246        depth = path->p_depth;
5247
5248        while (depth >= 0) {
5249                if (depth == path->p_depth) {
5250                        ex_start = path[depth].p_ext;
5251                        if (!ex_start)
5252                                return -EFSCORRUPTED;
5253
5254                        ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5255
5256                        err = ext4_access_path(handle, inode, path + depth);
5257                        if (err)
5258                                goto out;
5259
5260                        if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5261                                update = 1;
5262
5263                        while (ex_start <= ex_last) {
5264                                if (SHIFT == SHIFT_LEFT) {
5265                                        le32_add_cpu(&ex_start->ee_block,
5266                                                -shift);
5267                                        /* Try to merge to the left. */
5268                                        if ((ex_start >
5269                                            EXT_FIRST_EXTENT(path[depth].p_hdr))
5270                                            &&
5271                                            ext4_ext_try_to_merge_right(inode,
5272                                            path, ex_start - 1))
5273                                                ex_last--;
5274                                        else
5275                                                ex_start++;
5276                                } else {
5277                                        le32_add_cpu(&ex_last->ee_block, shift);
5278                                        ext4_ext_try_to_merge_right(inode, path,
5279                                                ex_last);
5280                                        ex_last--;
5281                                }
5282                        }
5283                        err = ext4_ext_dirty(handle, inode, path + depth);
5284                        if (err)
5285                                goto out;
5286
5287                        if (--depth < 0 || !update)
5288                                break;
5289                }
5290
5291                /* Update index too */
5292                err = ext4_access_path(handle, inode, path + depth);
5293                if (err)
5294                        goto out;
5295
5296                if (SHIFT == SHIFT_LEFT)
5297                        le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5298                else
5299                        le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5300                err = ext4_ext_dirty(handle, inode, path + depth);
5301                if (err)
5302                        goto out;
5303
5304                /* we are done if current index is not a starting index */
5305                if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5306                        break;
5307
5308                depth--;
5309        }
5310
5311out:
5312        return err;
5313}
5314
5315/*
5316 * ext4_ext_shift_extents:
5317 * All the extents which lies in the range from @start to the last allocated
5318 * block for the @inode are shifted either towards left or right (depending
5319 * upon @SHIFT) by @shift blocks.
5320 * On success, 0 is returned, error otherwise.
5321 */
5322static int
5323ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5324                       ext4_lblk_t start, ext4_lblk_t shift,
5325                       enum SHIFT_DIRECTION SHIFT)
5326{
5327        struct ext4_ext_path *path;
5328        int ret = 0, depth;
5329        struct ext4_extent *extent;
5330        ext4_lblk_t stop, *iterator, ex_start, ex_end;
5331
5332        /* Let path point to the last extent */
5333        path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5334                                EXT4_EX_NOCACHE);
5335        if (IS_ERR(path))
5336                return PTR_ERR(path);
5337
5338        depth = path->p_depth;
5339        extent = path[depth].p_ext;
5340        if (!extent)
5341                goto out;
5342
5343        stop = le32_to_cpu(extent->ee_block);
5344
5345       /*
5346         * In case of left shift, Don't start shifting extents until we make
5347         * sure the hole is big enough to accommodate the shift.
5348        */
5349        if (SHIFT == SHIFT_LEFT) {
5350                path = ext4_find_extent(inode, start - 1, &path,
5351                                        EXT4_EX_NOCACHE);
5352                if (IS_ERR(path))
5353                        return PTR_ERR(path);
5354                depth = path->p_depth;
5355                extent =  path[depth].p_ext;
5356                if (extent) {
5357                        ex_start = le32_to_cpu(extent->ee_block);
5358                        ex_end = le32_to_cpu(extent->ee_block) +
5359                                ext4_ext_get_actual_len(extent);
5360                } else {
5361                        ex_start = 0;
5362                        ex_end = 0;
5363                }
5364
5365                if ((start == ex_start && shift > ex_start) ||
5366                    (shift > start - ex_end)) {
5367                        ext4_ext_drop_refs(path);
5368                        kfree(path);
5369                        return -EINVAL;
5370                }
5371        }
5372
5373        /*
5374         * In case of left shift, iterator points to start and it is increased
5375         * till we reach stop. In case of right shift, iterator points to stop
5376         * and it is decreased till we reach start.
5377         */
5378        if (SHIFT == SHIFT_LEFT)
5379                iterator = &start;
5380        else
5381                iterator = &stop;
5382
5383        /*
5384         * Its safe to start updating extents.  Start and stop are unsigned, so
5385         * in case of right shift if extent with 0 block is reached, iterator
5386         * becomes NULL to indicate the end of the loop.
5387         */
5388        while (iterator && start <= stop) {
5389                path = ext4_find_extent(inode, *iterator, &path,
5390                                        EXT4_EX_NOCACHE);
5391                if (IS_ERR(path))
5392                        return PTR_ERR(path);
5393                depth = path->p_depth;
5394                extent = path[depth].p_ext;
5395                if (!extent) {
5396                        EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5397                                         (unsigned long) *iterator);
5398                        return -EFSCORRUPTED;
5399                }
5400                if (SHIFT == SHIFT_LEFT && *iterator >
5401                    le32_to_cpu(extent->ee_block)) {
5402                        /* Hole, move to the next extent */
5403                        if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5404                                path[depth].p_ext++;
5405                        } else {
5406                                *iterator = ext4_ext_next_allocated_block(path);
5407                                continue;
5408                        }
5409                }
5410
5411                if (SHIFT == SHIFT_LEFT) {
5412                        extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5413                        *iterator = le32_to_cpu(extent->ee_block) +
5414                                        ext4_ext_get_actual_len(extent);
5415                } else {
5416                        extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5417                        if (le32_to_cpu(extent->ee_block) > 0)
5418                                *iterator = le32_to_cpu(extent->ee_block) - 1;
5419                        else
5420                                /* Beginning is reached, end of the loop */
5421                                iterator = NULL;
5422                        /* Update path extent in case we need to stop */
5423                        while (le32_to_cpu(extent->ee_block) < start)
5424                                extent++;
5425                        path[depth].p_ext = extent;
5426                }
5427                ret = ext4_ext_shift_path_extents(path, shift, inode,
5428                                handle, SHIFT);
5429                if (ret)
5430                        break;
5431        }
5432out:
5433        ext4_ext_drop_refs(path);
5434        kfree(path);
5435        return ret;
5436}
5437
5438/*
5439 * ext4_collapse_range:
5440 * This implements the fallocate's collapse range functionality for ext4
5441 * Returns: 0 and non-zero on error.
5442 */
5443int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5444{
5445        struct super_block *sb = inode->i_sb;
5446        ext4_lblk_t punch_start, punch_stop;
5447        handle_t *handle;
5448        unsigned int credits;
5449        loff_t new_size, ioffset;
5450        int ret;
5451
5452        /*
5453         * We need to test this early because xfstests assumes that a
5454         * collapse range of (0, 1) will return EOPNOTSUPP if the file
5455         * system does not support collapse range.
5456         */
5457        if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5458                return -EOPNOTSUPP;
5459
5460        /* Collapse range works only on fs block size aligned offsets. */
5461        if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5462            len & (EXT4_CLUSTER_SIZE(sb) - 1))
5463                return -EINVAL;
5464
5465        if (!S_ISREG(inode->i_mode))
5466                return -EINVAL;
5467
5468        trace_ext4_collapse_range(inode, offset, len);
5469
5470        punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5471        punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5472
5473        /* Call ext4_force_commit to flush all data in case of data=journal. */
5474        if (ext4_should_journal_data(inode)) {
5475                ret = ext4_force_commit(inode->i_sb);
5476                if (ret)
5477                        return ret;
5478        }
5479
5480        inode_lock(inode);
5481        /*
5482         * There is no need to overlap collapse range with EOF, in which case
5483         * it is effectively a truncate operation
5484         */
5485        if (offset + len >= i_size_read(inode)) {
5486                ret = -EINVAL;
5487                goto out_mutex;
5488        }
5489
5490        /* Currently just for extent based files */
5491        if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5492                ret = -EOPNOTSUPP;
5493                goto out_mutex;
5494        }
5495
5496        /* Wait for existing dio to complete */
5497        ext4_inode_block_unlocked_dio(inode);
5498        inode_dio_wait(inode);
5499
5500        /*
5501         * Prevent page faults from reinstantiating pages we have released from
5502         * page cache.
5503         */
5504        down_write(&EXT4_I(inode)->i_mmap_sem);
5505        /*
5506         * Need to round down offset to be aligned with page size boundary
5507         * for page size > block size.
5508         */
5509        ioffset = round_down(offset, PAGE_SIZE);
5510        /*
5511         * Write tail of the last page before removed range since it will get
5512         * removed from the page cache below.
5513         */
5514        ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5515        if (ret)
5516                goto out_mmap;
5517        /*
5518         * Write data that will be shifted to preserve them when discarding
5519         * page cache below. We are also protected from pages becoming dirty
5520         * by i_mmap_sem.
5521         */
5522        ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5523                                           LLONG_MAX);
5524        if (ret)
5525                goto out_mmap;
5526        truncate_pagecache(inode, ioffset);
5527
5528        credits = ext4_writepage_trans_blocks(inode);
5529        handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5530        if (IS_ERR(handle)) {
5531                ret = PTR_ERR(handle);
5532                goto out_mmap;
5533        }
5534
5535        down_write(&EXT4_I(inode)->i_data_sem);
5536        ext4_discard_preallocations(inode);
5537
5538        ret = ext4_es_remove_extent(inode, punch_start,
5539                                    EXT_MAX_BLOCKS - punch_start);
5540        if (ret) {
5541                up_write(&EXT4_I(inode)->i_data_sem);
5542                goto out_stop;
5543        }
5544
5545        ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5546        if (ret) {
5547                up_write(&EXT4_I(inode)->i_data_sem);
5548                goto out_stop;
5549        }
5550        ext4_discard_preallocations(inode);
5551
5552        ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5553                                     punch_stop - punch_start, SHIFT_LEFT);
5554        if (ret) {
5555                up_write(&EXT4_I(inode)->i_data_sem);
5556                goto out_stop;
5557        }
5558
5559        new_size = i_size_read(inode) - len;
5560        i_size_write(inode, new_size);
5561        EXT4_I(inode)->i_disksize = new_size;
5562
5563        up_write(&EXT4_I(inode)->i_data_sem);
5564        if (IS_SYNC(inode))
5565                ext4_handle_sync(handle);
5566        inode->i_mtime = inode->i_ctime = current_time(inode);
5567        ext4_mark_inode_dirty(handle, inode);
5568        ext4_update_inode_fsync_trans(handle, inode, 1);
5569
5570out_stop:
5571        ext4_journal_stop(handle);
5572out_mmap:
5573        up_write(&EXT4_I(inode)->i_mmap_sem);
5574        ext4_inode_resume_unlocked_dio(inode);
5575out_mutex:
5576        inode_unlock(inode);
5577        return ret;
5578}
5579
5580/*
5581 * ext4_insert_range:
5582 * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5583 * The data blocks starting from @offset to the EOF are shifted by @len
5584 * towards right to create a hole in the @inode. Inode size is increased
5585 * by len bytes.
5586 * Returns 0 on success, error otherwise.
5587 */
5588int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5589{
5590        struct super_block *sb = inode->i_sb;
5591        handle_t *handle;
5592        struct ext4_ext_path *path;
5593        struct ext4_extent *extent;
5594        ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5595        unsigned int credits, ee_len;
5596        int ret = 0, depth, split_flag = 0;
5597        loff_t ioffset;
5598
5599        /*
5600         * We need to test this early because xfstests assumes that an
5601         * insert range of (0, 1) will return EOPNOTSUPP if the file
5602         * system does not support insert range.
5603         */
5604        if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5605                return -EOPNOTSUPP;
5606
5607        /* Insert range works only on fs block size aligned offsets. */
5608        if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5609                        len & (EXT4_CLUSTER_SIZE(sb) - 1))
5610                return -EINVAL;
5611
5612        if (!S_ISREG(inode->i_mode))
5613                return -EOPNOTSUPP;
5614
5615        trace_ext4_insert_range(inode, offset, len);
5616
5617        offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5618        len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5619
5620        /* Call ext4_force_commit to flush all data in case of data=journal */
5621        if (ext4_should_journal_data(inode)) {
5622                ret = ext4_force_commit(inode->i_sb);
5623                if (ret)
5624                        return ret;
5625        }
5626
5627        inode_lock(inode);
5628        /* Currently just for extent based files */
5629        if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5630                ret = -EOPNOTSUPP;
5631                goto out_mutex;
5632        }
5633
5634        /* Check for wrap through zero */
5635        if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5636                ret = -EFBIG;
5637                goto out_mutex;
5638        }
5639
5640        /* Offset should be less than i_size */
5641        if (offset >= i_size_read(inode)) {
5642                ret = -EINVAL;
5643                goto out_mutex;
5644        }
5645
5646        /* Wait for existing dio to complete */
5647        ext4_inode_block_unlocked_dio(inode);
5648        inode_dio_wait(inode);
5649
5650        /*
5651         * Prevent page faults from reinstantiating pages we have released from
5652         * page cache.
5653         */
5654        down_write(&EXT4_I(inode)->i_mmap_sem);
5655        /*
5656         * Need to round down to align start offset to page size boundary
5657         * for page size > block size.
5658         */
5659        ioffset = round_down(offset, PAGE_SIZE);
5660        /* Write out all dirty pages */
5661        ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5662                        LLONG_MAX);
5663        if (ret)
5664                goto out_mmap;
5665        truncate_pagecache(inode, ioffset);
5666
5667        credits = ext4_writepage_trans_blocks(inode);
5668        handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5669        if (IS_ERR(handle)) {
5670                ret = PTR_ERR(handle);
5671                goto out_mmap;
5672        }
5673
5674        /* Expand file to avoid data loss if there is error while shifting */
5675        inode->i_size += len;
5676        EXT4_I(inode)->i_disksize += len;
5677        inode->i_mtime = inode->i_ctime = current_time(inode);
5678        ret = ext4_mark_inode_dirty(handle, inode);
5679        if (ret)
5680                goto out_stop;
5681
5682        down_write(&EXT4_I(inode)->i_data_sem);
5683        ext4_discard_preallocations(inode);
5684
5685        path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5686        if (IS_ERR(path)) {
5687                up_write(&EXT4_I(inode)->i_data_sem);
5688                goto out_stop;
5689        }
5690
5691        depth = ext_depth(inode);
5692        extent = path[depth].p_ext;
5693        if (extent) {
5694                ee_start_lblk = le32_to_cpu(extent->ee_block);
5695                ee_len = ext4_ext_get_actual_len(extent);
5696
5697                /*
5698                 * If offset_lblk is not the starting block of extent, split
5699                 * the extent @offset_lblk
5700                 */
5701                if ((offset_lblk > ee_start_lblk) &&
5702                                (offset_lblk < (ee_start_lblk + ee_len))) {
5703                        if (ext4_ext_is_unwritten(extent))
5704                                split_flag = EXT4_EXT_MARK_UNWRIT1 |
5705                                        EXT4_EXT_MARK_UNWRIT2;
5706                        ret = ext4_split_extent_at(handle, inode, &path,
5707                                        offset_lblk, split_flag,
5708                                        EXT4_EX_NOCACHE |
5709                                        EXT4_GET_BLOCKS_PRE_IO |
5710                                        EXT4_GET_BLOCKS_METADATA_NOFAIL);
5711                }
5712
5713                ext4_ext_drop_refs(path);
5714                kfree(path);
5715                if (ret < 0) {
5716                        up_write(&EXT4_I(inode)->i_data_sem);
5717                        goto out_stop;
5718                }
5719        } else {
5720                ext4_ext_drop_refs(path);
5721                kfree(path);
5722        }
5723
5724        ret = ext4_es_remove_extent(inode, offset_lblk,
5725                        EXT_MAX_BLOCKS - offset_lblk);
5726        if (ret) {
5727                up_write(&EXT4_I(inode)->i_data_sem);
5728                goto out_stop;
5729        }
5730
5731        /*
5732         * if offset_lblk lies in a hole which is at start of file, use
5733         * ee_start_lblk to shift extents
5734         */
5735        ret = ext4_ext_shift_extents(inode, handle,
5736                ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5737                len_lblk, SHIFT_RIGHT);
5738
5739        up_write(&EXT4_I(inode)->i_data_sem);
5740        if (IS_SYNC(inode))
5741                ext4_handle_sync(handle);
5742        if (ret >= 0)
5743                ext4_update_inode_fsync_trans(handle, inode, 1);
5744
5745out_stop:
5746        ext4_journal_stop(handle);
5747out_mmap:
5748        up_write(&EXT4_I(inode)->i_mmap_sem);
5749        ext4_inode_resume_unlocked_dio(inode);
5750out_mutex:
5751        inode_unlock(inode);
5752        return ret;
5753}
5754
5755/**
5756 * ext4_swap_extents - Swap extents between two inodes
5757 *
5758 * @inode1:     First inode
5759 * @inode2:     Second inode
5760 * @lblk1:      Start block for first inode
5761 * @lblk2:      Start block for second inode
5762 * @count:      Number of blocks to swap
5763 * @mark_unwritten: Mark second inode's extents as unwritten after swap
5764 * @erp:        Pointer to save error value
5765 *
5766 * This helper routine does exactly what is promise "swap extents". All other
5767 * stuff such as page-cache locking consistency, bh mapping consistency or
5768 * extent's data copying must be performed by caller.
5769 * Locking:
5770 *              i_mutex is held for both inodes
5771 *              i_data_sem is locked for write for both inodes
5772 * Assumptions:
5773 *              All pages from requested range are locked for both inodes
5774 */
5775int
5776ext4_swap_extents(handle_t *handle, struct inode *inode1,
5777                     struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5778                  ext4_lblk_t count, int unwritten, int *erp)
5779{
5780        struct ext4_ext_path *path1 = NULL;
5781        struct ext4_ext_path *path2 = NULL;
5782        int replaced_count = 0;
5783
5784        BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5785        BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5786        BUG_ON(!inode_is_locked(inode1));
5787        BUG_ON(!inode_is_locked(inode2));
5788
5789        *erp = ext4_es_remove_extent(inode1, lblk1, count);
5790        if (unlikely(*erp))
5791                return 0;
5792        *erp = ext4_es_remove_extent(inode2, lblk2, count);
5793        if (unlikely(*erp))
5794                return 0;
5795
5796        while (count) {
5797                struct ext4_extent *ex1, *ex2, tmp_ex;
5798                ext4_lblk_t e1_blk, e2_blk;
5799                int e1_len, e2_len, len;
5800                int split = 0;
5801
5802                path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5803                if (IS_ERR(path1)) {
5804                        *erp = PTR_ERR(path1);
5805                        path1 = NULL;
5806                finish:
5807                        count = 0;
5808                        goto repeat;
5809                }
5810                path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5811                if (IS_ERR(path2)) {
5812                        *erp = PTR_ERR(path2);
5813                        path2 = NULL;
5814                        goto finish;
5815                }
5816                ex1 = path1[path1->p_depth].p_ext;
5817                ex2 = path2[path2->p_depth].p_ext;
5818                /* Do we have somthing to swap ? */
5819                if (unlikely(!ex2 || !ex1))
5820                        goto finish;
5821
5822                e1_blk = le32_to_cpu(ex1->ee_block);
5823                e2_blk = le32_to_cpu(ex2->ee_block);
5824                e1_len = ext4_ext_get_actual_len(ex1);
5825                e2_len = ext4_ext_get_actual_len(ex2);
5826
5827                /* Hole handling */
5828                if (!in_range(lblk1, e1_blk, e1_len) ||
5829                    !in_range(lblk2, e2_blk, e2_len)) {
5830                        ext4_lblk_t next1, next2;
5831
5832                        /* if hole after extent, then go to next extent */
5833                        next1 = ext4_ext_next_allocated_block(path1);
5834                        next2 = ext4_ext_next_allocated_block(path2);
5835                        /* If hole before extent, then shift to that extent */
5836                        if (e1_blk > lblk1)
5837                                next1 = e1_blk;
5838                        if (e2_blk > lblk2)
5839                                next2 = e2_blk;
5840                        /* Do we have something to swap */
5841                        if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5842                                goto finish;
5843                        /* Move to the rightest boundary */
5844                        len = next1 - lblk1;
5845                        if (len < next2 - lblk2)
5846                                len = next2 - lblk2;
5847                        if (len > count)
5848                                len = count;
5849                        lblk1 += len;
5850                        lblk2 += len;
5851                        count -= len;
5852                        goto repeat;
5853                }
5854
5855                /* Prepare left boundary */
5856                if (e1_blk < lblk1) {
5857                        split = 1;
5858                        *erp = ext4_force_split_extent_at(handle, inode1,
5859                                                &path1, lblk1, 0);
5860                        if (unlikely(*erp))
5861                                goto finish;
5862                }
5863                if (e2_blk < lblk2) {
5864                        split = 1;
5865                        *erp = ext4_force_split_extent_at(handle, inode2,
5866                                                &path2,  lblk2, 0);
5867                        if (unlikely(*erp))
5868                                goto finish;
5869                }
5870                /* ext4_split_extent_at() may result in leaf extent split,
5871                 * path must to be revalidated. */
5872                if (split)
5873                        goto repeat;
5874
5875                /* Prepare right boundary */
5876                len = count;
5877                if (len > e1_blk + e1_len - lblk1)
5878                        len = e1_blk + e1_len - lblk1;
5879                if (len > e2_blk + e2_len - lblk2)
5880                        len = e2_blk + e2_len - lblk2;
5881
5882                if (len != e1_len) {
5883                        split = 1;
5884                        *erp = ext4_force_split_extent_at(handle, inode1,
5885                                                &path1, lblk1 + len, 0);
5886                        if (unlikely(*erp))
5887                                goto finish;
5888                }
5889                if (len != e2_len) {
5890                        split = 1;
5891                        *erp = ext4_force_split_extent_at(handle, inode2,
5892                                                &path2, lblk2 + len, 0);
5893                        if (*erp)
5894                                goto finish;
5895                }
5896                /* ext4_split_extent_at() may result in leaf extent split,
5897                 * path must to be revalidated. */
5898                if (split)
5899                        goto repeat;
5900
5901                BUG_ON(e2_len != e1_len);
5902                *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5903                if (unlikely(*erp))
5904                        goto finish;
5905                *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5906                if (unlikely(*erp))
5907                        goto finish;
5908
5909                /* Both extents are fully inside boundaries. Swap it now */
5910                tmp_ex = *ex1;
5911                ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5912                ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5913                ex1->ee_len = cpu_to_le16(e2_len);
5914                ex2->ee_len = cpu_to_le16(e1_len);
5915                if (unwritten)
5916                        ext4_ext_mark_unwritten(ex2);
5917                if (ext4_ext_is_unwritten(&tmp_ex))
5918                        ext4_ext_mark_unwritten(ex1);
5919
5920                ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5921                ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5922                *erp = ext4_ext_dirty(handle, inode2, path2 +
5923                                      path2->p_depth);
5924                if (unlikely(*erp))
5925                        goto finish;
5926                *erp = ext4_ext_dirty(handle, inode1, path1 +
5927                                      path1->p_depth);
5928                /*
5929                 * Looks scarry ah..? second inode already points to new blocks,
5930                 * and it was successfully dirtied. But luckily error may happen
5931                 * only due to journal error, so full transaction will be
5932                 * aborted anyway.
5933                 */
5934                if (unlikely(*erp))
5935                        goto finish;
5936                lblk1 += len;
5937                lblk2 += len;
5938                replaced_count += len;
5939                count -= len;
5940
5941        repeat:
5942                ext4_ext_drop_refs(path1);
5943                kfree(path1);
5944                ext4_ext_drop_refs(path2);
5945                kfree(path2);
5946                path1 = path2 = NULL;
5947        }
5948        return replaced_count;
5949}
5950