fs/ext4/migrate.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  * Copyright IBM Corporation, 2007
   4  * Author Aneesh Kumar K.V <[email protected]>
   5  *
   6  */
   7
   8 #include <linux/slab.h>
   9 #include "ext4_jbd2.h"
  10 #include "ext4_extents.h"
  11
  12 /*
  13  * The contiguous blocks details which can be
  14  * represented by a single extent
  15  */
  16 struct migrate_struct {
  17         ext4_lblk_t first_block, last_block, curr_block;
  18         ext4_fsblk_t first_pblock, last_pblock;
  19 };
  20
  21 static int finish_range(handle_t *handle, struct inode *inode,
  22                                 struct migrate_struct *lb)
  23
  24 {
  25         int retval = 0, needed;
  26         struct ext4_extent newext;
  27         struct ext4_ext_path *path;
  28         if (lb->first_pblock == 0)
  29                 return 0;
  30
  31         /* Add the extent to temp inode*/
  32         newext.ee_block = cpu_to_le32(lb->first_block);
  33         newext.ee_len   = cpu_to_le16(lb->last_block - lb->first_block + 1);
  34         ext4_ext_store_pblock(&newext, lb->first_pblock);
  35         /* Locking only for convenience since we are operating on temp inode */
  36         down_write(&EXT4_I(inode)->i_data_sem);
  37         path = ext4_find_extent(inode, lb->first_block, NULL, 0);
  38         if (IS_ERR(path)) {
  39                 retval = PTR_ERR(path);
  40                 path = NULL;
  41                 goto err_out;
  42         }
  43
  44         /*
  45          * Calculate the credit needed to inserting this extent
  46          * Since we are doing this in loop we may accumulate extra
  47          * credit. But below we try to not accumulate too much
  48          * of them by restarting the journal.
  49          */
  50         needed = ext4_ext_calc_credits_for_single_extent(inode,
  51                     lb->last_block - lb->first_block + 1, path);
  52
  53         retval = ext4_datasem_ensure_credits(handle, inode, needed, needed, 0);
  54         if (retval < 0)
  55                 goto err_out;
  56         retval = ext4_ext_insert_extent(handle, inode, &path, &newext, 0);
  57 err_out:
  58         up_write((&EXT4_I(inode)->i_data_sem));
  59         ext4_free_ext_path(path);
  60         lb->first_pblock = 0;
  61         return retval;
  62 }
  63
  64 static int update_extent_range(handle_t *handle, struct inode *inode,
  65                                ext4_fsblk_t pblock, struct migrate_struct *lb)
  66 {
  67         int retval;
  68         /*
  69          * See if we can add on to the existing range (if it exists)
  70          */
  71         if (lb->first_pblock &&
  72                 (lb->last_pblock+1 == pblock) &&
  73                 (lb->last_block+1 == lb->curr_block)) {
  74                 lb->last_pblock = pblock;
  75                 lb->last_block = lb->curr_block;
  76                 lb->curr_block++;
  77                 return 0;
  78         }
  79         /*
  80          * Start a new range.
  81          */
  82         retval = finish_range(handle, inode, lb);
  83         lb->first_pblock = lb->last_pblock = pblock;
  84         lb->first_block = lb->last_block = lb->curr_block;
  85         lb->curr_block++;
  86         return retval;
  87 }
  88
  89 static int update_ind_extent_range(handle_t *handle, struct inode *inode,
  90                                    ext4_fsblk_t pblock,
  91                                    struct migrate_struct *lb)
  92 {
  93         struct buffer_head *bh;
  94         __le32 *i_data;
  95         int i, retval = 0;
  96         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
  97
  98         bh = ext4_sb_bread(inode->i_sb, pblock, 0);
  99         if (IS_ERR(bh))
 100                 return PTR_ERR(bh);
 101
 102         i_data = (__le32 *)bh->b_data;
 103         for (i = 0; i < max_entries; i++) {
 104                 if (i_data[i]) {
 105                         retval = update_extent_range(handle, inode,
 106                                                 le32_to_cpu(i_data[i]), lb);
 107                         if (retval)
 108                                 break;
 109                 } else {
 110                         lb->curr_block++;
 111                 }
 112         }
 113         put_bh(bh);
 114         return retval;
 115
 116 }
 117
 118 static int update_dind_extent_range(handle_t *handle, struct inode *inode,
 119                                     ext4_fsblk_t pblock,
 120                                     struct migrate_struct *lb)
 121 {
 122         struct buffer_head *bh;
 123         __le32 *i_data;
 124         int i, retval = 0;
 125         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 126
 127         bh = ext4_sb_bread(inode->i_sb, pblock, 0);
 128         if (IS_ERR(bh))
 129                 return PTR_ERR(bh);
 130
 131         i_data = (__le32 *)bh->b_data;
 132         for (i = 0; i < max_entries; i++) {
 133                 if (i_data[i]) {
 134                         retval = update_ind_extent_range(handle, inode,
 135                                                 le32_to_cpu(i_data[i]), lb);
 136                         if (retval)
 137                                 break;
 138                 } else {
 139                         /* Only update the file block number */
 140                         lb->curr_block += max_entries;
 141                 }
 142         }
 143         put_bh(bh);
 144         return retval;
 145
 146 }
 147
 148 static int update_tind_extent_range(handle_t *handle, struct inode *inode,
 149                                     ext4_fsblk_t pblock,
 150                                     struct migrate_struct *lb)
 151 {
 152         struct buffer_head *bh;
 153         __le32 *i_data;
 154         int i, retval = 0;
 155         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 156
 157         bh = ext4_sb_bread(inode->i_sb, pblock, 0);
 158         if (IS_ERR(bh))
 159                 return PTR_ERR(bh);
 160
 161         i_data = (__le32 *)bh->b_data;
 162         for (i = 0; i < max_entries; i++) {
 163                 if (i_data[i]) {
 164                         retval = update_dind_extent_range(handle, inode,
 165                                                 le32_to_cpu(i_data[i]), lb);
 166                         if (retval)
 167                                 break;
 168                 } else {
 169                         /* Only update the file block number */
 170                         lb->curr_block += max_entries * max_entries;
 171                 }
 172         }
 173         put_bh(bh);
 174         return retval;
 175
 176 }
 177
 178 static int free_dind_blocks(handle_t *handle,
 179                                 struct inode *inode, __le32 i_data)
 180 {
 181         int i;
 182         __le32 *tmp_idata;
 183         struct buffer_head *bh;
 184         struct super_block *sb = inode->i_sb;
 185         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 186         int err;
 187
 188         bh = ext4_sb_bread(sb, le32_to_cpu(i_data), 0);
 189         if (IS_ERR(bh))
 190                 return PTR_ERR(bh);
 191
 192         tmp_idata = (__le32 *)bh->b_data;
 193         for (i = 0; i < max_entries; i++) {
 194                 if (tmp_idata[i]) {
 195                         err = ext4_journal_ensure_credits(handle,
 196                                 EXT4_RESERVE_TRANS_BLOCKS,
 197                                 ext4_free_metadata_revoke_credits(sb, 1));
 198                         if (err < 0) {
 199                                 put_bh(bh);
 200                                 return err;
 201                         }
 202                         ext4_free_blocks(handle, inode, NULL,
 203                                          le32_to_cpu(tmp_idata[i]), 1,
 204                                          EXT4_FREE_BLOCKS_METADATA |
 205                                          EXT4_FREE_BLOCKS_FORGET);
 206                 }
 207         }
 208         put_bh(bh);
 209         err = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
 210                                 ext4_free_metadata_revoke_credits(sb, 1));
 211         if (err < 0)
 212                 return err;
 213         ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
 214                          EXT4_FREE_BLOCKS_METADATA |
 215                          EXT4_FREE_BLOCKS_FORGET);
 216         return 0;
 217 }
 218
 219 static int free_tind_blocks(handle_t *handle,
 220                                 struct inode *inode, __le32 i_data)
 221 {
 222         int i, retval = 0;
 223         __le32 *tmp_idata;
 224         struct buffer_head *bh;
 225         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 226
 227         bh = ext4_sb_bread(inode->i_sb, le32_to_cpu(i_data), 0);
 228         if (IS_ERR(bh))
 229                 return PTR_ERR(bh);
 230
 231         tmp_idata = (__le32 *)bh->b_data;
 232         for (i = 0; i < max_entries; i++) {
 233                 if (tmp_idata[i]) {
 234                         retval = free_dind_blocks(handle,
 235                                         inode, tmp_idata[i]);
 236                         if (retval) {
 237                                 put_bh(bh);
 238                                 return retval;
 239                         }
 240                 }
 241         }
 242         put_bh(bh);
 243         retval = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
 244                         ext4_free_metadata_revoke_credits(inode->i_sb, 1));
 245         if (retval < 0)
 246                 return retval;
 247         ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
 248                          EXT4_FREE_BLOCKS_METADATA |
 249                          EXT4_FREE_BLOCKS_FORGET);
 250         return 0;
 251 }
 252
 253 static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
 254 {
 255         int retval;
 256
 257         /* ei->i_data[EXT4_IND_BLOCK] */
 258         if (i_data[0]) {
 259                 retval = ext4_journal_ensure_credits(handle,
 260                         EXT4_RESERVE_TRANS_BLOCKS,
 261                         ext4_free_metadata_revoke_credits(inode->i_sb, 1));
 262                 if (retval < 0)
 263                         return retval;
 264                 ext4_free_blocks(handle, inode, NULL,
 265                                 le32_to_cpu(i_data[0]), 1,
 266                                  EXT4_FREE_BLOCKS_METADATA |
 267                                  EXT4_FREE_BLOCKS_FORGET);
 268         }
 269
 270         /* ei->i_data[EXT4_DIND_BLOCK] */
 271         if (i_data[1]) {
 272                 retval = free_dind_blocks(handle, inode, i_data[1]);
 273                 if (retval)
 274                         return retval;
 275         }
 276
 277         /* ei->i_data[EXT4_TIND_BLOCK] */
 278         if (i_data[2]) {
 279                 retval = free_tind_blocks(handle, inode, i_data[2]);
 280                 if (retval)
 281                         return retval;
 282         }
 283         return 0;
 284 }
 285
 286 static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
 287                                                 struct inode *tmp_inode)
 288 {
 289         int retval, retval2 = 0;
 290         __le32  i_data[3];
 291         struct ext4_inode_info *ei = EXT4_I(inode);
 292         struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
 293
 294         /*
 295          * One credit accounted for writing the
 296          * i_data field of the original inode
 297          */
 298         retval = ext4_journal_ensure_credits(handle, 1, 0);
 299         if (retval < 0)
 300                 goto err_out;
 301
 302         i_data[0] = ei->i_data[EXT4_IND_BLOCK];
 303         i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
 304         i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
 305
 306         down_write(&EXT4_I(inode)->i_data_sem);
 307         /*
 308          * if EXT4_STATE_EXT_MIGRATE is cleared a block allocation
 309          * happened after we started the migrate. We need to
 310          * fail the migrate
 311          */
 312         if (!ext4_test_inode_state(inode, EXT4_STATE_EXT_MIGRATE)) {
 313                 retval = -EAGAIN;
 314                 up_write(&EXT4_I(inode)->i_data_sem);
 315                 goto err_out;
 316         } else
 317                 ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 318         /*
 319          * We have the extent map build with the tmp inode.
 320          * Now copy the i_data across
 321          */
 322         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
 323         memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));
 324
 325         /*
 326          * Update i_blocks with the new blocks that got
 327          * allocated while adding extents for extent index
 328          * blocks.
 329          *
 330          * While converting to extents we need not
 331          * update the original inode i_blocks for extent blocks
 332          * via quota APIs. The quota update happened via tmp_inode already.
 333          */
 334         spin_lock(&inode->i_lock);
 335         inode->i_blocks += tmp_inode->i_blocks;
 336         spin_unlock(&inode->i_lock);
 337         up_write(&EXT4_I(inode)->i_data_sem);
 338
 339         /*
 340          * We mark the inode dirty after, because we decrement the
 341          * i_blocks when freeing the indirect meta-data blocks
 342          */
 343         retval = free_ind_block(handle, inode, i_data);
 344         retval2 = ext4_mark_inode_dirty(handle, inode);
 345         if (unlikely(retval2 && !retval))
 346                 retval = retval2;
 347
 348 err_out:
 349         return retval;
 350 }
 351
 352 static int free_ext_idx(handle_t *handle, struct inode *inode,
 353                                         struct ext4_extent_idx *ix)
 354 {
 355         int i, retval = 0;
 356         ext4_fsblk_t block;
 357         struct buffer_head *bh;
 358         struct ext4_extent_header *eh;
 359
 360         block = ext4_idx_pblock(ix);
 361         bh = ext4_sb_bread(inode->i_sb, block, 0);
 362         if (IS_ERR(bh))
 363                 return PTR_ERR(bh);
 364
 365         eh = (struct ext4_extent_header *)bh->b_data;
 366         if (eh->eh_depth != 0) {
 367                 ix = EXT_FIRST_INDEX(eh);
 368                 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
 369                         retval = free_ext_idx(handle, inode, ix);
 370                         if (retval) {
 371                                 put_bh(bh);
 372                                 return retval;
 373                         }
 374                 }
 375         }
 376         put_bh(bh);
 377         retval = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
 378                         ext4_free_metadata_revoke_credits(inode->i_sb, 1));
 379         if (retval < 0)
 380                 return retval;
 381         ext4_free_blocks(handle, inode, NULL, block, 1,
 382                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
 383         return 0;
 384 }
 385
 386 /*
 387  * Free the extent meta data blocks only
 388  */
 389 static int free_ext_block(handle_t *handle, struct inode *inode)
 390 {
 391         int i, retval = 0;
 392         struct ext4_inode_info *ei = EXT4_I(inode);
 393         struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
 394         struct ext4_extent_idx *ix;
 395         if (eh->eh_depth == 0)
 396                 /*
 397                  * No extra blocks allocated for extent meta data
 398                  */
 399                 return 0;
 400         ix = EXT_FIRST_INDEX(eh);
 401         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
 402                 retval = free_ext_idx(handle, inode, ix);
 403                 if (retval)
 404                         return retval;
 405         }
 406         return retval;
 407 }
 408
 409 int ext4_ext_migrate(struct inode *inode)
 410 {
 411         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 412         handle_t *handle;
 413         int retval = 0, i;
 414         __le32 *i_data;
 415         struct ext4_inode_info *ei;
 416         struct inode *tmp_inode = NULL;
 417         struct migrate_struct lb;
 418         unsigned long max_entries;
 419         __u32 goal, tmp_csum_seed;
 420         uid_t owner[2];
 421
 422         /*
 423          * If the filesystem does not support extents, or the inode
 424          * already is extent-based, error out.
 425          */
 426         if (!ext4_has_feature_extents(inode->i_sb) ||
 427             ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) ||
 428             ext4_has_inline_data(inode))
 429                 return -EINVAL;
 430
 431         if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
 432                 /*
 433                  * don't migrate fast symlink
 434                  */
 435                 return retval;
 436
 437         percpu_down_write(&sbi->s_writepages_rwsem);
 438
 439         /*
 440          * Worst case we can touch the allocation bitmaps and a block
 441          * group descriptor block.  We do need to worry about
 442          * credits for modifying the quota inode.
 443          */
 444         handle = ext4_journal_start(inode, EXT4_HT_MIGRATE,
 445                 3 + EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
 446
 447         if (IS_ERR(handle)) {
 448                 retval = PTR_ERR(handle);
 449                 goto out_unlock;
 450         }
 451         goal = (((inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb)) *
 452                 EXT4_INODES_PER_GROUP(inode->i_sb)) + 1;
 453         owner[0] = i_uid_read(inode);
 454         owner[1] = i_gid_read(inode);
 455         tmp_inode = ext4_new_inode(handle, d_inode(inode->i_sb->s_root),
 456                                    S_IFREG, NULL, goal, owner, 0);
 457         if (IS_ERR(tmp_inode)) {
 458                 retval = PTR_ERR(tmp_inode);
 459                 ext4_journal_stop(handle);
 460                 goto out_unlock;
 461         }
 462         /*
 463          * Use the correct seed for checksum (i.e. the seed from 'inode').  This
 464          * is so that the metadata blocks will have the correct checksum after
 465          * the migration.
 466          */
 467         ei = EXT4_I(inode);
 468         tmp_csum_seed = EXT4_I(tmp_inode)->i_csum_seed;
 469         EXT4_I(tmp_inode)->i_csum_seed = ei->i_csum_seed;
 470         i_size_write(tmp_inode, i_size_read(inode));
 471         /*
 472          * Set the i_nlink to zero so it will be deleted later
 473          * when we drop inode reference.
 474          */
 475         clear_nlink(tmp_inode);
 476
 477         ext4_ext_tree_init(handle, tmp_inode);
 478         ext4_journal_stop(handle);
 479
 480         /*
 481          * start with one credit accounted for
 482          * superblock modification.
 483          *
 484          * For the tmp_inode we already have committed the
 485          * transaction that created the inode. Later as and
 486          * when we add extents we extent the journal
 487          */
 488         /*
 489          * Even though we take i_rwsem we can still cause block
 490          * allocation via mmap write to holes. If we have allocated
 491          * new blocks we fail migrate.  New block allocation will
 492          * clear EXT4_STATE_EXT_MIGRATE flag.  The flag is updated
 493          * with i_data_sem held to prevent racing with block
 494          * allocation.
 495          */
 496         down_read(&EXT4_I(inode)->i_data_sem);
 497         ext4_set_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 498         up_read((&EXT4_I(inode)->i_data_sem));
 499
 500         handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
 501         if (IS_ERR(handle)) {
 502                 retval = PTR_ERR(handle);
 503                 goto out_tmp_inode;
 504         }
 505
 506         i_data = ei->i_data;
 507         memset(&lb, 0, sizeof(lb));
 508
 509         /* 32 bit block address 4 bytes */
 510         max_entries = inode->i_sb->s_blocksize >> 2;
 511         for (i = 0; i < EXT4_NDIR_BLOCKS; i++) {
 512                 if (i_data[i]) {
 513                         retval = update_extent_range(handle, tmp_inode,
 514                                                 le32_to_cpu(i_data[i]), &lb);
 515                         if (retval)
 516                                 goto err_out;
 517                 } else
 518                         lb.curr_block++;
 519         }
 520         if (i_data[EXT4_IND_BLOCK]) {
 521                 retval = update_ind_extent_range(handle, tmp_inode,
 522                                 le32_to_cpu(i_data[EXT4_IND_BLOCK]), &lb);
 523                 if (retval)
 524                         goto err_out;
 525         } else
 526                 lb.curr_block += max_entries;
 527         if (i_data[EXT4_DIND_BLOCK]) {
 528                 retval = update_dind_extent_range(handle, tmp_inode,
 529                                 le32_to_cpu(i_data[EXT4_DIND_BLOCK]), &lb);
 530                 if (retval)
 531                         goto err_out;
 532         } else
 533                 lb.curr_block += max_entries * max_entries;
 534         if (i_data[EXT4_TIND_BLOCK]) {
 535                 retval = update_tind_extent_range(handle, tmp_inode,
 536                                 le32_to_cpu(i_data[EXT4_TIND_BLOCK]), &lb);
 537                 if (retval)
 538                         goto err_out;
 539         }
 540         /*
 541          * Build the last extent
 542          */
 543         retval = finish_range(handle, tmp_inode, &lb);
 544 err_out:
 545         if (retval)
 546                 /*
 547                  * Failure case delete the extent information with the
 548                  * tmp_inode
 549                  */
 550                 free_ext_block(handle, tmp_inode);
 551         else {
 552                 retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
 553                 if (retval)
 554                         /*
 555                          * if we fail to swap inode data free the extent
 556                          * details of the tmp inode
 557                          */
 558                         free_ext_block(handle, tmp_inode);
 559         }
 560
 561         /* We mark the tmp_inode dirty via ext4_ext_tree_init. */
 562         retval = ext4_journal_ensure_credits(handle, 1, 0);
 563         if (retval < 0)
 564                 goto out_stop;
 565         /*
 566          * Mark the tmp_inode as of size zero
 567          */
 568         i_size_write(tmp_inode, 0);
 569
 570         /*
 571          * set the  i_blocks count to zero
 572          * so that the ext4_evict_inode() does the
 573          * right job
 574          *
 575          * We don't need to take the i_lock because
 576          * the inode is not visible to user space.
 577          */
 578         tmp_inode->i_blocks = 0;
 579         EXT4_I(tmp_inode)->i_csum_seed = tmp_csum_seed;
 580
 581         /* Reset the extent details */
 582         ext4_ext_tree_init(handle, tmp_inode);
 583 out_stop:
 584         ext4_journal_stop(handle);
 585 out_tmp_inode:
 586         unlock_new_inode(tmp_inode);
 587         iput(tmp_inode);
 588 out_unlock:
 589         percpu_up_write(&sbi->s_writepages_rwsem);
 590         return retval;
 591 }
 592
 593 /*
 594  * Migrate a simple extent-based inode to use the i_blocks[] array
 595  */
 596 int ext4_ind_migrate(struct inode *inode)
 597 {
 598         struct ext4_extent_header       *eh;
 599         struct ext4_sb_info             *sbi = EXT4_SB(inode->i_sb);
 600         struct ext4_super_block         *es = sbi->s_es;
 601         struct ext4_inode_info          *ei = EXT4_I(inode);
 602         struct ext4_extent              *ex;
 603         unsigned int                    i, len;
 604         ext4_lblk_t                     start, end;
 605         ext4_fsblk_t                    blk;
 606         handle_t                        *handle;
 607         int                             ret, ret2 = 0;
 608
 609         if (!ext4_has_feature_extents(inode->i_sb) ||
 610             (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 611                 return -EINVAL;
 612
 613         if (ext4_has_feature_bigalloc(inode->i_sb))
 614                 return -EOPNOTSUPP;
 615
 616         /*
 617          * In order to get correct extent info, force all delayed allocation
 618          * blocks to be allocated, otherwise delayed allocation blocks may not
 619          * be reflected and bypass the checks on extent header.
 620          */
 621         if (test_opt(inode->i_sb, DELALLOC))
 622                 ext4_alloc_da_blocks(inode);
 623
 624         percpu_down_write(&sbi->s_writepages_rwsem);
 625
 626         handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
 627         if (IS_ERR(handle)) {
 628                 ret = PTR_ERR(handle);
 629                 goto out_unlock;
 630         }
 631
 632         down_write(&EXT4_I(inode)->i_data_sem);
 633         ret = ext4_ext_check_inode(inode);
 634         if (ret)
 635                 goto errout;
 636
 637         eh = ext_inode_hdr(inode);
 638         ex  = EXT_FIRST_EXTENT(eh);
 639         if (ext4_blocks_count(es) > EXT4_MAX_BLOCK_FILE_PHYS ||
 640             eh->eh_depth != 0 || le16_to_cpu(eh->eh_entries) > 1) {
 641                 ret = -EOPNOTSUPP;
 642                 goto errout;
 643         }
 644         if (eh->eh_entries == 0)
 645                 blk = len = start = end = 0;
 646         else {
 647                 len = le16_to_cpu(ex->ee_len);
 648                 blk = ext4_ext_pblock(ex);
 649                 start = le32_to_cpu(ex->ee_block);
 650                 end = start + len - 1;
 651                 if (end >= EXT4_NDIR_BLOCKS) {
 652                         ret = -EOPNOTSUPP;
 653                         goto errout;
 654                 }
 655         }
 656
 657         ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
 658         memset(ei->i_data, 0, sizeof(ei->i_data));
 659         for (i = start; i <= end; i++)
 660                 ei->i_data[i] = cpu_to_le32(blk++);
 661         ret2 = ext4_mark_inode_dirty(handle, inode);
 662         if (unlikely(ret2 && !ret))
 663                 ret = ret2;
 664 errout:
 665         ext4_journal_stop(handle);
 666         up_write(&EXT4_I(inode)->i_data_sem);
 667 out_unlock:
 668         percpu_up_write(&sbi->s_writepages_rwsem);
 669         return ret;
 670 }