fs/ext4/move_extent.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd.
   4  * Written by Takashi Sato <t-sato@yk.jp.nec.com>
   5  *            Akira Fujita <a-fujita@rs.jp.nec.com>
   6  */
   7
   8 #include <linux/fs.h>
   9 #include <linux/quotaops.h>
  10 #include <linux/slab.h>
  11 #include <linux/sched/mm.h>
  12 #include "ext4_jbd2.h"
  13 #include "ext4.h"
  14 #include "ext4_extents.h"
  15
  16 /**
  17  * get_ext_path() - Find an extent path for designated logical block number.
  18  * @inode:      inode to be searched
  19  * @lblock:     logical block number to find an extent path
  20  * @path:       pointer to an extent path
  21  *
  22  * ext4_find_extent wrapper. Return an extent path pointer on success,
  23  * or an error pointer on failure.
  24  */
  25 static inline struct ext4_ext_path *
  26 get_ext_path(struct inode *inode, ext4_lblk_t lblock,
  27              struct ext4_ext_path *path)
  28 {
  29         path = ext4_find_extent(inode, lblock, path, EXT4_EX_NOCACHE);
  30         if (IS_ERR(path))
  31                 return path;
  32         if (path[ext_depth(inode)].p_ext == NULL) {
  33                 ext4_free_ext_path(path);
  34                 return ERR_PTR(-ENODATA);
  35         }
  36         return path;
  37 }
  38
  39 /**
  40  * ext4_double_down_write_data_sem() - write lock two inodes's i_data_sem
  41  * @first: inode to be locked
  42  * @second: inode to be locked
  43  *
  44  * Acquire write lock of i_data_sem of the two inodes
  45  */
  46 void
  47 ext4_double_down_write_data_sem(struct inode *first, struct inode *second)
  48 {
  49         if (first < second) {
  50                 down_write(&EXT4_I(first)->i_data_sem);
  51                 down_write_nested(&EXT4_I(second)->i_data_sem, I_DATA_SEM_OTHER);
  52         } else {
  53                 down_write(&EXT4_I(second)->i_data_sem);
  54                 down_write_nested(&EXT4_I(first)->i_data_sem, I_DATA_SEM_OTHER);
  55
  56         }
  57 }
  58
  59 /**
  60  * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem
  61  *
  62  * @orig_inode:         original inode structure to be released its lock first
  63  * @donor_inode:        donor inode structure to be released its lock second
  64  * Release write lock of i_data_sem of two inodes (orig and donor).
  65  */
  66 void
  67 ext4_double_up_write_data_sem(struct inode *orig_inode,
  68                               struct inode *donor_inode)
  69 {
  70         up_write(&EXT4_I(orig_inode)->i_data_sem);
  71         up_write(&EXT4_I(donor_inode)->i_data_sem);
  72 }
  73
  74 /**
  75  * mext_check_coverage - Check that all extents in range has the same type
  76  *
  77  * @inode:              inode in question
  78  * @from:               block offset of inode
  79  * @count:              block count to be checked
  80  * @unwritten:          extents expected to be unwritten
  81  * @err:                pointer to save error value
  82  *
  83  * Return 1 if all extents in range has expected type, and zero otherwise.
  84  */
  85 static int
  86 mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
  87                     int unwritten, int *err)
  88 {
  89         struct ext4_ext_path *path = NULL;
  90         struct ext4_extent *ext;
  91         int ret = 0;
  92         ext4_lblk_t last = from + count;
  93         while (from < last) {
  94                 path = get_ext_path(inode, from, path);
  95                 if (IS_ERR(path)) {
  96                         *err = PTR_ERR(path);
  97                         return ret;
  98                 }
  99                 ext = path[ext_depth(inode)].p_ext;
 100                 if (unwritten != ext4_ext_is_unwritten(ext))
 101                         goto out;
 102                 from += ext4_ext_get_actual_len(ext);
 103         }
 104         ret = 1;
 105 out:
 106         ext4_free_ext_path(path);
 107         return ret;
 108 }
 109
 110 /**
 111  * mext_folio_double_lock - Grab and lock folio on both @inode1 and @inode2
 112  *
 113  * @inode1:     the inode structure
 114  * @inode2:     the inode structure
 115  * @index1:     folio index
 116  * @index2:     folio index
 117  * @folio:      result folio vector
 118  *
 119  * Grab two locked folio for inode's by inode order
 120  */
 121 static int
 122 mext_folio_double_lock(struct inode *inode1, struct inode *inode2,
 123                       pgoff_t index1, pgoff_t index2, struct folio *folio[2])
 124 {
 125         struct address_space *mapping[2];
 126         unsigned int flags;
 127
 128         BUG_ON(!inode1 || !inode2);
 129         if (inode1 < inode2) {
 130                 mapping[0] = inode1->i_mapping;
 131                 mapping[1] = inode2->i_mapping;
 132         } else {
 133                 swap(index1, index2);
 134                 mapping[0] = inode2->i_mapping;
 135                 mapping[1] = inode1->i_mapping;
 136         }
 137
 138         flags = memalloc_nofs_save();
 139         folio[0] = __filemap_get_folio(mapping[0], index1, FGP_WRITEBEGIN,
 140                         mapping_gfp_mask(mapping[0]));
 141         if (IS_ERR(folio[0])) {
 142                 memalloc_nofs_restore(flags);
 143                 return PTR_ERR(folio[0]);
 144         }
 145
 146         folio[1] = __filemap_get_folio(mapping[1], index2, FGP_WRITEBEGIN,
 147                         mapping_gfp_mask(mapping[1]));
 148         memalloc_nofs_restore(flags);
 149         if (IS_ERR(folio[1])) {
 150                 folio_unlock(folio[0]);
 151                 folio_put(folio[0]);
 152                 return PTR_ERR(folio[1]);
 153         }
 154         /*
 155          * __filemap_get_folio() may not wait on folio's writeback if
 156          * BDI not demand that. But it is reasonable to be very conservative
 157          * here and explicitly wait on folio's writeback
 158          */
 159         folio_wait_writeback(folio[0]);
 160         folio_wait_writeback(folio[1]);
 161         if (inode1 > inode2)
 162                 swap(folio[0], folio[1]);
 163
 164         return 0;
 165 }
 166
 167 /* Force folio buffers uptodate w/o dropping folio's lock */
 168 static int mext_page_mkuptodate(struct folio *folio, size_t from, size_t to)
 169 {
 170         struct inode *inode = folio->mapping->host;
 171         sector_t block;
 172         struct buffer_head *bh, *head;
 173         unsigned int blocksize, block_start, block_end;
 174         int nr = 0;
 175         bool partial = false;
 176
 177         BUG_ON(!folio_test_locked(folio));
 178         BUG_ON(folio_test_writeback(folio));
 179
 180         if (folio_test_uptodate(folio))
 181                 return 0;
 182
 183         blocksize = i_blocksize(inode);
 184         head = folio_buffers(folio);
 185         if (!head)
 186                 head = create_empty_buffers(folio, blocksize, 0);
 187
 188         block = folio_pos(folio) >> inode->i_blkbits;
 189         block_end = 0;
 190         bh = head;
 191         do {
 192                 block_start = block_end;
 193                 block_end = block_start + blocksize;
 194                 if (block_end <= from || block_start >= to) {
 195                         if (!buffer_uptodate(bh))
 196                                 partial = true;
 197                         continue;
 198                 }
 199                 if (buffer_uptodate(bh))
 200                         continue;
 201                 if (!buffer_mapped(bh)) {
 202                         int err = ext4_get_block(inode, block, bh, 0);
 203                         if (err)
 204                                 return err;
 205                         if (!buffer_mapped(bh)) {
 206                                 folio_zero_range(folio, block_start, blocksize);
 207                                 set_buffer_uptodate(bh);
 208                                 continue;
 209                         }
 210                 }
 211                 lock_buffer(bh);
 212                 if (buffer_uptodate(bh)) {
 213                         unlock_buffer(bh);
 214                         continue;
 215                 }
 216                 ext4_read_bh_nowait(bh, 0, NULL, false);
 217                 nr++;
 218         } while (block++, (bh = bh->b_this_page) != head);
 219
 220         /* No io required */
 221         if (!nr)
 222                 goto out;
 223
 224         bh = head;
 225         do {
 226                 if (bh_offset(bh) + blocksize <= from)
 227                         continue;
 228                 if (bh_offset(bh) > to)
 229                         break;
 230                 wait_on_buffer(bh);
 231                 if (buffer_uptodate(bh))
 232                         continue;
 233                 return -EIO;
 234         } while ((bh = bh->b_this_page) != head);
 235 out:
 236         if (!partial)
 237                 folio_mark_uptodate(folio);
 238         return 0;
 239 }
 240
 241 /**
 242  * move_extent_per_page - Move extent data per page
 243  *
 244  * @o_filp:                     file structure of original file
 245  * @donor_inode:                donor inode
 246  * @orig_page_offset:           page index on original file
 247  * @donor_page_offset:          page index on donor file
 248  * @data_offset_in_page:        block index where data swapping starts
 249  * @block_len_in_page:          the number of blocks to be swapped
 250  * @unwritten:                  orig extent is unwritten or not
 251  * @err:                        pointer to save return value
 252  *
 253  * Save the data in original inode blocks and replace original inode extents
 254  * with donor inode extents by calling ext4_swap_extents().
 255  * Finally, write out the saved data in new original inode blocks. Return
 256  * replaced block count.
 257  */
 258 static int
 259 move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
 260                      pgoff_t orig_page_offset, pgoff_t donor_page_offset,
 261                      int data_offset_in_page,
 262                      int block_len_in_page, int unwritten, int *err)
 263 {
 264         struct inode *orig_inode = file_inode(o_filp);
 265         struct folio *folio[2] = {NULL, NULL};
 266         handle_t *handle;
 267         ext4_lblk_t orig_blk_offset, donor_blk_offset;
 268         unsigned long blocksize = orig_inode->i_sb->s_blocksize;
 269         unsigned int tmp_data_size, data_size, replaced_size;
 270         int i, err2, jblocks, retries = 0;
 271         int replaced_count = 0;
 272         int from = data_offset_in_page << orig_inode->i_blkbits;
 273         int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits;
 274         struct super_block *sb = orig_inode->i_sb;
 275         struct buffer_head *bh = NULL;
 276
 277         /*
 278          * It needs twice the amount of ordinary journal buffers because
 279          * inode and donor_inode may change each different metadata blocks.
 280          */
 281 again:
 282         *err = 0;
 283         jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
 284         handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks);
 285         if (IS_ERR(handle)) {
 286                 *err = PTR_ERR(handle);
 287                 return 0;
 288         }
 289
 290         orig_blk_offset = orig_page_offset * blocks_per_page +
 291                 data_offset_in_page;
 292
 293         donor_blk_offset = donor_page_offset * blocks_per_page +
 294                 data_offset_in_page;
 295
 296         /* Calculate data_size */
 297         if ((orig_blk_offset + block_len_in_page - 1) ==
 298             ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
 299                 /* Replace the last block */
 300                 tmp_data_size = orig_inode->i_size & (blocksize - 1);
 301                 /*
 302                  * If data_size equal zero, it shows data_size is multiples of
 303                  * blocksize. So we set appropriate value.
 304                  */
 305                 if (tmp_data_size == 0)
 306                         tmp_data_size = blocksize;
 307
 308                 data_size = tmp_data_size +
 309                         ((block_len_in_page - 1) << orig_inode->i_blkbits);
 310         } else
 311                 data_size = block_len_in_page << orig_inode->i_blkbits;
 312
 313         replaced_size = data_size;
 314
 315         *err = mext_folio_double_lock(orig_inode, donor_inode, orig_page_offset,
 316                                      donor_page_offset, folio);
 317         if (unlikely(*err < 0))
 318                 goto stop_journal;
 319         /*
 320          * If orig extent was unwritten it can become initialized
 321          * at any time after i_data_sem was dropped, in order to
 322          * serialize with delalloc we have recheck extent while we
 323          * hold page's lock, if it is still the case data copy is not
 324          * necessary, just swap data blocks between orig and donor.
 325          */
 326
 327         VM_BUG_ON_FOLIO(folio_test_large(folio[0]), folio[0]);
 328         VM_BUG_ON_FOLIO(folio_test_large(folio[1]), folio[1]);
 329         VM_BUG_ON_FOLIO(folio_nr_pages(folio[0]) != folio_nr_pages(folio[1]), folio[1]);
 330
 331         if (unwritten) {
 332                 ext4_double_down_write_data_sem(orig_inode, donor_inode);
 333                 /* If any of extents in range became initialized we have to
 334                  * fallback to data copying */
 335                 unwritten = mext_check_coverage(orig_inode, orig_blk_offset,
 336                                                 block_len_in_page, 1, err);
 337                 if (*err)
 338                         goto drop_data_sem;
 339
 340                 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset,
 341                                                  block_len_in_page, 1, err);
 342                 if (*err)
 343                         goto drop_data_sem;
 344
 345                 if (!unwritten) {
 346                         ext4_double_up_write_data_sem(orig_inode, donor_inode);
 347                         goto data_copy;
 348                 }
 349                 if (!filemap_release_folio(folio[0], 0) ||
 350                     !filemap_release_folio(folio[1], 0)) {
 351                         *err = -EBUSY;
 352                         goto drop_data_sem;
 353                 }
 354                 replaced_count = ext4_swap_extents(handle, orig_inode,
 355                                                    donor_inode, orig_blk_offset,
 356                                                    donor_blk_offset,
 357                                                    block_len_in_page, 1, err);
 358         drop_data_sem:
 359                 ext4_double_up_write_data_sem(orig_inode, donor_inode);
 360                 goto unlock_folios;
 361         }
 362 data_copy:
 363         *err = mext_page_mkuptodate(folio[0], from, from + replaced_size);
 364         if (*err)
 365                 goto unlock_folios;
 366
 367         /* At this point all buffers in range are uptodate, old mapping layout
 368          * is no longer required, try to drop it now. */
 369         if (!filemap_release_folio(folio[0], 0) ||
 370             !filemap_release_folio(folio[1], 0)) {
 371                 *err = -EBUSY;
 372                 goto unlock_folios;
 373         }
 374         ext4_double_down_write_data_sem(orig_inode, donor_inode);
 375         replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode,
 376                                                orig_blk_offset, donor_blk_offset,
 377                                            block_len_in_page, 1, err);
 378         ext4_double_up_write_data_sem(orig_inode, donor_inode);
 379         if (*err) {
 380                 if (replaced_count) {
 381                         block_len_in_page = replaced_count;
 382                         replaced_size =
 383                                 block_len_in_page << orig_inode->i_blkbits;
 384                 } else
 385                         goto unlock_folios;
 386         }
 387         /* Perform all necessary steps similar write_begin()/write_end()
 388          * but keeping in mind that i_size will not change */
 389         bh = folio_buffers(folio[0]);
 390         if (!bh)
 391                 bh = create_empty_buffers(folio[0],
 392                                 1 << orig_inode->i_blkbits, 0);
 393         for (i = 0; i < data_offset_in_page; i++)
 394                 bh = bh->b_this_page;
 395         for (i = 0; i < block_len_in_page; i++) {
 396                 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0);
 397                 if (*err < 0)
 398                         goto repair_branches;
 399                 bh = bh->b_this_page;
 400         }
 401
 402         block_commit_write(&folio[0]->page, from, from + replaced_size);
 403
 404         /* Even in case of data=writeback it is reasonable to pin
 405          * inode to transaction, to prevent unexpected data loss */
 406         *err = ext4_jbd2_inode_add_write(handle, orig_inode,
 407                         (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size);
 408
 409 unlock_folios:
 410         folio_unlock(folio[0]);
 411         folio_put(folio[0]);
 412         folio_unlock(folio[1]);
 413         folio_put(folio[1]);
 414 stop_journal:
 415         ext4_journal_stop(handle);
 416         if (*err == -ENOSPC &&
 417             ext4_should_retry_alloc(sb, &retries))
 418                 goto again;
 419         /* Buffer was busy because probably is pinned to journal transaction,
 420          * force transaction commit may help to free it. */
 421         if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal &&
 422             jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal))
 423                 goto again;
 424         return replaced_count;
 425
 426 repair_branches:
 427         /*
 428          * This should never ever happen!
 429          * Extents are swapped already, but we are not able to copy data.
 430          * Try to swap extents to it's original places
 431          */
 432         ext4_double_down_write_data_sem(orig_inode, donor_inode);
 433         replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode,
 434                                                orig_blk_offset, donor_blk_offset,
 435                                            block_len_in_page, 0, &err2);
 436         ext4_double_up_write_data_sem(orig_inode, donor_inode);
 437         if (replaced_count != block_len_in_page) {
 438                 ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset),
 439                                        EIO, "Unable to copy data block,"
 440                                        " data will be lost.");
 441                 *err = -EIO;
 442         }
 443         replaced_count = 0;
 444         goto unlock_folios;
 445 }
 446
 447 /**
 448  * mext_check_arguments - Check whether move extent can be done
 449  *
 450  * @orig_inode:         original inode
 451  * @donor_inode:        donor inode
 452  * @orig_start:         logical start offset in block for orig
 453  * @donor_start:        logical start offset in block for donor
 454  * @len:                the number of blocks to be moved
 455  *
 456  * Check the arguments of ext4_move_extents() whether the files can be
 457  * exchanged with each other.
 458  * Return 0 on success, or a negative error value on failure.
 459  */
 460 static int
 461 mext_check_arguments(struct inode *orig_inode,
 462                      struct inode *donor_inode, __u64 orig_start,
 463                      __u64 donor_start, __u64 *len)
 464 {
 465         __u64 orig_eof, donor_eof;
 466         unsigned int blkbits = orig_inode->i_blkbits;
 467         unsigned int blocksize = 1 << blkbits;
 468
 469         orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits;
 470         donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits;
 471
 472
 473         if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
 474                 ext4_debug("ext4 move extent: suid or sgid is set"
 475                            " to donor file [ino:orig %lu, donor %lu]\n",
 476                            orig_inode->i_ino, donor_inode->i_ino);
 477                 return -EINVAL;
 478         }
 479
 480         if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
 481                 return -EPERM;
 482
 483         /* Ext4 move extent does not support swap files */
 484         if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
 485                 ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n",
 486                         orig_inode->i_ino, donor_inode->i_ino);
 487                 return -ETXTBSY;
 488         }
 489
 490         if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) {
 491                 ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n",
 492                         orig_inode->i_ino, donor_inode->i_ino);
 493                 return -EOPNOTSUPP;
 494         }
 495
 496         /* Ext4 move extent supports only extent based file */
 497         if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) {
 498                 ext4_debug("ext4 move extent: orig file is not extents "
 499                         "based file [ino:orig %lu]\n", orig_inode->i_ino);
 500                 return -EOPNOTSUPP;
 501         } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) {
 502                 ext4_debug("ext4 move extent: donor file is not extents "
 503                         "based file [ino:donor %lu]\n", donor_inode->i_ino);
 504                 return -EOPNOTSUPP;
 505         }
 506
 507         if ((!orig_inode->i_size) || (!donor_inode->i_size)) {
 508                 ext4_debug("ext4 move extent: File size is 0 byte\n");
 509                 return -EINVAL;
 510         }
 511
 512         /* Start offset should be same */
 513         if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) !=
 514             (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) {
 515                 ext4_debug("ext4 move extent: orig and donor's start "
 516                         "offsets are not aligned [ino:orig %lu, donor %lu]\n",
 517                         orig_inode->i_ino, donor_inode->i_ino);
 518                 return -EINVAL;
 519         }
 520
 521         if ((orig_start >= EXT_MAX_BLOCKS) ||
 522             (donor_start >= EXT_MAX_BLOCKS) ||
 523             (*len > EXT_MAX_BLOCKS) ||
 524             (donor_start + *len >= EXT_MAX_BLOCKS) ||
 525             (orig_start + *len >= EXT_MAX_BLOCKS))  {
 526                 ext4_debug("ext4 move extent: Can't handle over [%u] blocks "
 527                         "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS,
 528                         orig_inode->i_ino, donor_inode->i_ino);
 529                 return -EINVAL;
 530         }
 531         if (orig_eof <= orig_start)
 532                 *len = 0;
 533         else if (orig_eof < orig_start + *len - 1)
 534                 *len = orig_eof - orig_start;
 535         if (donor_eof <= donor_start)
 536                 *len = 0;
 537         else if (donor_eof < donor_start + *len - 1)
 538                 *len = donor_eof - donor_start;
 539         if (!*len) {
 540                 ext4_debug("ext4 move extent: len should not be 0 "
 541                         "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
 542                         donor_inode->i_ino);
 543                 return -EINVAL;
 544         }
 545
 546         return 0;
 547 }
 548
 549 /**
 550  * ext4_move_extents - Exchange the specified range of a file
 551  *
 552  * @o_filp:             file structure of the original file
 553  * @d_filp:             file structure of the donor file
 554  * @orig_blk:           start offset in block for orig
 555  * @donor_blk:          start offset in block for donor
 556  * @len:                the number of blocks to be moved
 557  * @moved_len:          moved block length
 558  *
 559  * This function returns 0 and moved block length is set in moved_len
 560  * if succeed, otherwise returns error value.
 561  *
 562  */
 563 int
 564 ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
 565                   __u64 donor_blk, __u64 len, __u64 *moved_len)
 566 {
 567         struct inode *orig_inode = file_inode(o_filp);
 568         struct inode *donor_inode = file_inode(d_filp);
 569         struct ext4_ext_path *path = NULL;
 570         int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits;
 571         ext4_lblk_t o_end, o_start = orig_blk;
 572         ext4_lblk_t d_start = donor_blk;
 573         int ret;
 574
 575         if (orig_inode->i_sb != donor_inode->i_sb) {
 576                 ext4_debug("ext4 move extent: The argument files "
 577                         "should be in same FS [ino:orig %lu, donor %lu]\n",
 578                         orig_inode->i_ino, donor_inode->i_ino);
 579                 return -EINVAL;
 580         }
 581
 582         /* orig and donor should be different inodes */
 583         if (orig_inode == donor_inode) {
 584                 ext4_debug("ext4 move extent: The argument files should not "
 585                         "be same inode [ino:orig %lu, donor %lu]\n",
 586                         orig_inode->i_ino, donor_inode->i_ino);
 587                 return -EINVAL;
 588         }
 589
 590         /* Regular file check */
 591         if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
 592                 ext4_debug("ext4 move extent: The argument files should be "
 593                         "regular file [ino:orig %lu, donor %lu]\n",
 594                         orig_inode->i_ino, donor_inode->i_ino);
 595                 return -EINVAL;
 596         }
 597
 598         /* TODO: it's not obvious how to swap blocks for inodes with full
 599            journaling enabled */
 600         if (ext4_should_journal_data(orig_inode) ||
 601             ext4_should_journal_data(donor_inode)) {
 602                 ext4_msg(orig_inode->i_sb, KERN_ERR,
 603                          "Online defrag not supported with data journaling");
 604                 return -EOPNOTSUPP;
 605         }
 606
 607         if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) {
 608                 ext4_msg(orig_inode->i_sb, KERN_ERR,
 609                          "Online defrag not supported for encrypted files");
 610                 return -EOPNOTSUPP;
 611         }
 612
 613         /* Protect orig and donor inodes against a truncate */
 614         lock_two_nondirectories(orig_inode, donor_inode);
 615
 616         /* Wait for all existing dio workers */
 617         inode_dio_wait(orig_inode);
 618         inode_dio_wait(donor_inode);
 619
 620         /* Protect extent tree against block allocations via delalloc */
 621         ext4_double_down_write_data_sem(orig_inode, donor_inode);
 622         /* Check the filesystem environment whether move_extent can be done */
 623         ret = mext_check_arguments(orig_inode, donor_inode, orig_blk,
 624                                     donor_blk, &len);
 625         if (ret)
 626                 goto out;
 627         o_end = o_start + len;
 628
 629         *moved_len = 0;
 630         while (o_start < o_end) {
 631                 struct ext4_extent *ex;
 632                 ext4_lblk_t cur_blk, next_blk;
 633                 pgoff_t orig_page_index, donor_page_index;
 634                 int offset_in_page;
 635                 int unwritten, cur_len;
 636
 637                 path = get_ext_path(orig_inode, o_start, path);
 638                 if (IS_ERR(path)) {
 639                         ret = PTR_ERR(path);
 640                         goto out;
 641                 }
 642                 ex = path[path->p_depth].p_ext;
 643                 cur_blk = le32_to_cpu(ex->ee_block);
 644                 cur_len = ext4_ext_get_actual_len(ex);
 645                 /* Check hole before the start pos */
 646                 if (cur_blk + cur_len - 1 < o_start) {
 647                         next_blk = ext4_ext_next_allocated_block(path);
 648                         if (next_blk == EXT_MAX_BLOCKS) {
 649                                 ret = -ENODATA;
 650                                 goto out;
 651                         }
 652                         d_start += next_blk - o_start;
 653                         o_start = next_blk;
 654                         continue;
 655                 /* Check hole after the start pos */
 656                 } else if (cur_blk > o_start) {
 657                         /* Skip hole */
 658                         d_start += cur_blk - o_start;
 659                         o_start = cur_blk;
 660                         /* Extent inside requested range ?*/
 661                         if (cur_blk >= o_end)
 662                                 goto out;
 663                 } else { /* in_range(o_start, o_blk, o_len) */
 664                         cur_len += cur_blk - o_start;
 665                 }
 666                 unwritten = ext4_ext_is_unwritten(ex);
 667                 if (o_end - o_start < cur_len)
 668                         cur_len = o_end - o_start;
 669
 670                 orig_page_index = o_start >> (PAGE_SHIFT -
 671                                                orig_inode->i_blkbits);
 672                 donor_page_index = d_start >> (PAGE_SHIFT -
 673                                                donor_inode->i_blkbits);
 674                 offset_in_page = o_start % blocks_per_page;
 675                 if (cur_len > blocks_per_page - offset_in_page)
 676                         cur_len = blocks_per_page - offset_in_page;
 677                 /*
 678                  * Up semaphore to avoid following problems:
 679                  * a. transaction deadlock among ext4_journal_start,
 680                  *    ->write_begin via pagefault, and jbd2_journal_commit
 681                  * b. racing with ->read_folio, ->write_begin, and
 682                  *    ext4_get_block in move_extent_per_page
 683                  */
 684                 ext4_double_up_write_data_sem(orig_inode, donor_inode);
 685                 /* Swap original branches with new branches */
 686                 *moved_len += move_extent_per_page(o_filp, donor_inode,
 687                                      orig_page_index, donor_page_index,
 688                                      offset_in_page, cur_len,
 689                                      unwritten, &ret);
 690                 ext4_double_down_write_data_sem(orig_inode, donor_inode);
 691                 if (ret < 0)
 692                         break;
 693                 o_start += cur_len;
 694                 d_start += cur_len;
 695         }
 696
 697 out:
 698         if (*moved_len) {
 699                 ext4_discard_preallocations(orig_inode);
 700                 ext4_discard_preallocations(donor_inode);
 701         }
 702
 703         ext4_free_ext_path(path);
 704         ext4_double_up_write_data_sem(orig_inode, donor_inode);
 705         unlock_two_nondirectories(orig_inode, donor_inode);
 706
 707         return ret;
 708 }