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 * @ppath: pointer to an extent path pointer (for output) 21 * 22 * ext4_find_extent wrapper. Return 0 on success, or a negative error value 23 * on failure. 24 */ 25 static inline int 26 get_ext_path(struct inode *inode, ext4_lblk_t lblock, 27 struct ext4_ext_path **ppath) 28 { 29 struct ext4_ext_path *path; 30 31 path = ext4_find_extent(inode, lblock, ppath, EXT4_EX_NOCACHE); 32 if (IS_ERR(path)) 33 return PTR_ERR(path); 34 if (path[ext_depth(inode)].p_ext == NULL) { 35 ext4_free_ext_path(path); 36 *ppath = NULL; 37 return -ENODATA; 38 } 39 *ppath = path; 40 return 0; 41 } 42 43 /** 44 * ext4_double_down_write_data_sem() - write lock two inodes's i_data_sem 45 * @first: inode to be locked 46 * @second: inode to be locked 47 * 48 * Acquire write lock of i_data_sem of the two inodes 49 */ 50 void 51 ext4_double_down_write_data_sem(struct inode *first, struct inode *second) 52 { 53 if (first < second) { 54 down_write(&EXT4_I(first)->i_data_sem); 55 down_write_nested(&EXT4_I(second)->i_data_sem, I_DATA_SEM_OTHER); 56 } else { 57 down_write(&EXT4_I(second)->i_data_sem); 58 down_write_nested(&EXT4_I(first)->i_data_sem, I_DATA_SEM_OTHER); 59 60 } 61 } 62 63 /** 64 * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem 65 * 66 * @orig_inode: original inode structure to be released its lock first 67 * @donor_inode: donor inode structure to be released its lock second 68 * Release write lock of i_data_sem of two inodes (orig and donor). 69 */ 70 void 71 ext4_double_up_write_data_sem(struct inode *orig_inode, 72 struct inode *donor_inode) 73 { 74 up_write(&EXT4_I(orig_inode)->i_data_sem); 75 up_write(&EXT4_I(donor_inode)->i_data_sem); 76 } 77 78 /** 79 * mext_check_coverage - Check that all extents in range has the same type 80 * 81 * @inode: inode in question 82 * @from: block offset of inode 83 * @count: block count to be checked 84 * @unwritten: extents expected to be unwritten 85 * @err: pointer to save error value 86 * 87 * Return 1 if all extents in range has expected type, and zero otherwise. 88 */ 89 static int 90 mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count, 91 int unwritten, int *err) 92 { 93 struct ext4_ext_path *path = NULL; 94 struct ext4_extent *ext; 95 int ret = 0; 96 ext4_lblk_t last = from + count; 97 while (from < last) { 98 *err = get_ext_path(inode, from, &path); 99 if (*err) 100 goto out; 101 ext = path[ext_depth(inode)].p_ext; 102 if (unwritten != ext4_ext_is_unwritten(ext)) 103 goto out; 104 from += ext4_ext_get_actual_len(ext); 105 } 106 ret = 1; 107 out: 108 ext4_free_ext_path(path); 109 return ret; 110 } 111 112 /** 113 * mext_folio_double_lock - Grab and lock folio on both @inode1 and @inode2 114 * 115 * @inode1: the inode structure 116 * @inode2: the inode structure 117 * @index1: folio index 118 * @index2: folio index 119 * @folio: result folio vector 120 * 121 * Grab two locked folio for inode's by inode order 122 */ 123 static int 124 mext_folio_double_lock(struct inode *inode1, struct inode *inode2, 125 pgoff_t index1, pgoff_t index2, struct folio *folio[2]) 126 { 127 struct address_space *mapping[2]; 128 unsigned int flags; 129 130 BUG_ON(!inode1 || !inode2); 131 if (inode1 < inode2) { 132 mapping[0] = inode1->i_mapping; 133 mapping[1] = inode2->i_mapping; 134 } else { 135 swap(index1, index2); 136 mapping[0] = inode2->i_mapping; 137 mapping[1] = inode1->i_mapping; 138 } 139 140 flags = memalloc_nofs_save(); 141 folio[0] = __filemap_get_folio(mapping[0], index1, FGP_WRITEBEGIN, 142 mapping_gfp_mask(mapping[0])); 143 if (IS_ERR(folio[0])) { 144 memalloc_nofs_restore(flags); 145 return PTR_ERR(folio[0]); 146 } 147 148 folio[1] = __filemap_get_folio(mapping[1], index2, FGP_WRITEBEGIN, 149 mapping_gfp_mask(mapping[1])); 150 memalloc_nofs_restore(flags); 151 if (IS_ERR(folio[1])) { 152 folio_unlock(folio[0]); 153 folio_put(folio[0]); 154 return PTR_ERR(folio[1]); 155 } 156 /* 157 * __filemap_get_folio() may not wait on folio's writeback if 158 * BDI not demand that. But it is reasonable to be very conservative 159 * here and explicitly wait on folio's writeback 160 */ 161 folio_wait_writeback(folio[0]); 162 folio_wait_writeback(folio[1]); 163 if (inode1 > inode2) 164 swap(folio[0], folio[1]); 165 166 return 0; 167 } 168 169 /* Force page buffers uptodate w/o dropping page's lock */ 170 static int 171 mext_page_mkuptodate(struct folio *folio, unsigned from, unsigned to) 172 { 173 struct inode *inode = folio->mapping->host; 174 sector_t block; 175 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; 176 unsigned int blocksize, block_start, block_end; 177 int i, err, nr = 0, partial = 0; 178 BUG_ON(!folio_test_locked(folio)); 179 BUG_ON(folio_test_writeback(folio)); 180 181 if (folio_test_uptodate(folio)) 182 return 0; 183 184 blocksize = i_blocksize(inode); 185 head = folio_buffers(folio); 186 if (!head) 187 head = create_empty_buffers(folio, blocksize, 0); 188 189 block = (sector_t)folio->index << (PAGE_SHIFT - inode->i_blkbits); 190 for (bh = head, block_start = 0; bh != head || !block_start; 191 block++, block_start = block_end, bh = bh->b_this_page) { 192 block_end = block_start + blocksize; 193 if (block_end <= from || block_start >= to) { 194 if (!buffer_uptodate(bh)) 195 partial = 1; 196 continue; 197 } 198 if (buffer_uptodate(bh)) 199 continue; 200 if (!buffer_mapped(bh)) { 201 err = ext4_get_block(inode, block, bh, 0); 202 if (err) 203 return err; 204 if (!buffer_mapped(bh)) { 205 folio_zero_range(folio, block_start, blocksize); 206 set_buffer_uptodate(bh); 207 continue; 208 } 209 } 210 BUG_ON(nr >= MAX_BUF_PER_PAGE); 211 arr[nr++] = bh; 212 } 213 /* No io required */ 214 if (!nr) 215 goto out; 216 217 for (i = 0; i < nr; i++) { 218 bh = arr[i]; 219 if (!bh_uptodate_or_lock(bh)) { 220 err = ext4_read_bh(bh, 0, NULL); 221 if (err) 222 return err; 223 } 224 } 225 out: 226 if (!partial) 227 folio_mark_uptodate(folio); 228 return 0; 229 } 230 231 /** 232 * move_extent_per_page - Move extent data per page 233 * 234 * @o_filp: file structure of original file 235 * @donor_inode: donor inode 236 * @orig_page_offset: page index on original file 237 * @donor_page_offset: page index on donor file 238 * @data_offset_in_page: block index where data swapping starts 239 * @block_len_in_page: the number of blocks to be swapped 240 * @unwritten: orig extent is unwritten or not 241 * @err: pointer to save return value 242 * 243 * Save the data in original inode blocks and replace original inode extents 244 * with donor inode extents by calling ext4_swap_extents(). 245 * Finally, write out the saved data in new original inode blocks. Return 246 * replaced block count. 247 */ 248 static int 249 move_extent_per_page(struct file *o_filp, struct inode *donor_inode, 250 pgoff_t orig_page_offset, pgoff_t donor_page_offset, 251 int data_offset_in_page, 252 int block_len_in_page, int unwritten, int *err) 253 { 254 struct inode *orig_inode = file_inode(o_filp); 255 struct folio *folio[2] = {NULL, NULL}; 256 handle_t *handle; 257 ext4_lblk_t orig_blk_offset, donor_blk_offset; 258 unsigned long blocksize = orig_inode->i_sb->s_blocksize; 259 unsigned int tmp_data_size, data_size, replaced_size; 260 int i, err2, jblocks, retries = 0; 261 int replaced_count = 0; 262 int from = data_offset_in_page << orig_inode->i_blkbits; 263 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 264 struct super_block *sb = orig_inode->i_sb; 265 struct buffer_head *bh = NULL; 266 267 /* 268 * It needs twice the amount of ordinary journal buffers because 269 * inode and donor_inode may change each different metadata blocks. 270 */ 271 again: 272 *err = 0; 273 jblocks = ext4_writepage_trans_blocks(orig_inode) * 2; 274 handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks); 275 if (IS_ERR(handle)) { 276 *err = PTR_ERR(handle); 277 return 0; 278 } 279 280 orig_blk_offset = orig_page_offset * blocks_per_page + 281 data_offset_in_page; 282 283 donor_blk_offset = donor_page_offset * blocks_per_page + 284 data_offset_in_page; 285 286 /* Calculate data_size */ 287 if ((orig_blk_offset + block_len_in_page - 1) == 288 ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) { 289 /* Replace the last block */ 290 tmp_data_size = orig_inode->i_size & (blocksize - 1); 291 /* 292 * If data_size equal zero, it shows data_size is multiples of 293 * blocksize. So we set appropriate value. 294 */ 295 if (tmp_data_size == 0) 296 tmp_data_size = blocksize; 297 298 data_size = tmp_data_size + 299 ((block_len_in_page - 1) << orig_inode->i_blkbits); 300 } else 301 data_size = block_len_in_page << orig_inode->i_blkbits; 302 303 replaced_size = data_size; 304 305 *err = mext_folio_double_lock(orig_inode, donor_inode, orig_page_offset, 306 donor_page_offset, folio); 307 if (unlikely(*err < 0)) 308 goto stop_journal; 309 /* 310 * If orig extent was unwritten it can become initialized 311 * at any time after i_data_sem was dropped, in order to 312 * serialize with delalloc we have recheck extent while we 313 * hold page's lock, if it is still the case data copy is not 314 * necessary, just swap data blocks between orig and donor. 315 */ 316 317 VM_BUG_ON_FOLIO(folio_test_large(folio[0]), folio[0]); 318 VM_BUG_ON_FOLIO(folio_test_large(folio[1]), folio[1]); 319 VM_BUG_ON_FOLIO(folio_nr_pages(folio[0]) != folio_nr_pages(folio[1]), folio[1]); 320 321 if (unwritten) { 322 ext4_double_down_write_data_sem(orig_inode, donor_inode); 323 /* If any of extents in range became initialized we have to 324 * fallback to data copying */ 325 unwritten = mext_check_coverage(orig_inode, orig_blk_offset, 326 block_len_in_page, 1, err); 327 if (*err) 328 goto drop_data_sem; 329 330 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset, 331 block_len_in_page, 1, err); 332 if (*err) 333 goto drop_data_sem; 334 335 if (!unwritten) { 336 ext4_double_up_write_data_sem(orig_inode, donor_inode); 337 goto data_copy; 338 } 339 if (!filemap_release_folio(folio[0], 0) || 340 !filemap_release_folio(folio[1], 0)) { 341 *err = -EBUSY; 342 goto drop_data_sem; 343 } 344 replaced_count = ext4_swap_extents(handle, orig_inode, 345 donor_inode, orig_blk_offset, 346 donor_blk_offset, 347 block_len_in_page, 1, err); 348 drop_data_sem: 349 ext4_double_up_write_data_sem(orig_inode, donor_inode); 350 goto unlock_folios; 351 } 352 data_copy: 353 *err = mext_page_mkuptodate(folio[0], from, from + replaced_size); 354 if (*err) 355 goto unlock_folios; 356 357 /* At this point all buffers in range are uptodate, old mapping layout 358 * is no longer required, try to drop it now. */ 359 if (!filemap_release_folio(folio[0], 0) || 360 !filemap_release_folio(folio[1], 0)) { 361 *err = -EBUSY; 362 goto unlock_folios; 363 } 364 ext4_double_down_write_data_sem(orig_inode, donor_inode); 365 replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, 366 orig_blk_offset, donor_blk_offset, 367 block_len_in_page, 1, err); 368 ext4_double_up_write_data_sem(orig_inode, donor_inode); 369 if (*err) { 370 if (replaced_count) { 371 block_len_in_page = replaced_count; 372 replaced_size = 373 block_len_in_page << orig_inode->i_blkbits; 374 } else 375 goto unlock_folios; 376 } 377 /* Perform all necessary steps similar write_begin()/write_end() 378 * but keeping in mind that i_size will not change */ 379 bh = folio_buffers(folio[0]); 380 if (!bh) 381 bh = create_empty_buffers(folio[0], 382 1 << orig_inode->i_blkbits, 0); 383 for (i = 0; i < data_offset_in_page; i++) 384 bh = bh->b_this_page; 385 for (i = 0; i < block_len_in_page; i++) { 386 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); 387 if (*err < 0) 388 goto repair_branches; 389 bh = bh->b_this_page; 390 } 391 392 block_commit_write(&folio[0]->page, from, from + replaced_size); 393 394 /* Even in case of data=writeback it is reasonable to pin 395 * inode to transaction, to prevent unexpected data loss */ 396 *err = ext4_jbd2_inode_add_write(handle, orig_inode, 397 (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size); 398 399 unlock_folios: 400 folio_unlock(folio[0]); 401 folio_put(folio[0]); 402 folio_unlock(folio[1]); 403 folio_put(folio[1]); 404 stop_journal: 405 ext4_journal_stop(handle); 406 if (*err == -ENOSPC && 407 ext4_should_retry_alloc(sb, &retries)) 408 goto again; 409 /* Buffer was busy because probably is pinned to journal transaction, 410 * force transaction commit may help to free it. */ 411 if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal && 412 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal)) 413 goto again; 414 return replaced_count; 415 416 repair_branches: 417 /* 418 * This should never ever happen! 419 * Extents are swapped already, but we are not able to copy data. 420 * Try to swap extents to it's original places 421 */ 422 ext4_double_down_write_data_sem(orig_inode, donor_inode); 423 replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode, 424 orig_blk_offset, donor_blk_offset, 425 block_len_in_page, 0, &err2); 426 ext4_double_up_write_data_sem(orig_inode, donor_inode); 427 if (replaced_count != block_len_in_page) { 428 ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset), 429 EIO, "Unable to copy data block," 430 " data will be lost."); 431 *err = -EIO; 432 } 433 replaced_count = 0; 434 goto unlock_folios; 435 } 436 437 /** 438 * mext_check_arguments - Check whether move extent can be done 439 * 440 * @orig_inode: original inode 441 * @donor_inode: donor inode 442 * @orig_start: logical start offset in block for orig 443 * @donor_start: logical start offset in block for donor 444 * @len: the number of blocks to be moved 445 * 446 * Check the arguments of ext4_move_extents() whether the files can be 447 * exchanged with each other. 448 * Return 0 on success, or a negative error value on failure. 449 */ 450 static int 451 mext_check_arguments(struct inode *orig_inode, 452 struct inode *donor_inode, __u64 orig_start, 453 __u64 donor_start, __u64 *len) 454 { 455 __u64 orig_eof, donor_eof; 456 unsigned int blkbits = orig_inode->i_blkbits; 457 unsigned int blocksize = 1 << blkbits; 458 459 orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits; 460 donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits; 461 462 463 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { 464 ext4_debug("ext4 move extent: suid or sgid is set" 465 " to donor file [ino:orig %lu, donor %lu]\n", 466 orig_inode->i_ino, donor_inode->i_ino); 467 return -EINVAL; 468 } 469 470 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) 471 return -EPERM; 472 473 /* Ext4 move extent does not support swap files */ 474 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { 475 ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n", 476 orig_inode->i_ino, donor_inode->i_ino); 477 return -ETXTBSY; 478 } 479 480 if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) { 481 ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n", 482 orig_inode->i_ino, donor_inode->i_ino); 483 return -EOPNOTSUPP; 484 } 485 486 /* Ext4 move extent supports only extent based file */ 487 if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) { 488 ext4_debug("ext4 move extent: orig file is not extents " 489 "based file [ino:orig %lu]\n", orig_inode->i_ino); 490 return -EOPNOTSUPP; 491 } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) { 492 ext4_debug("ext4 move extent: donor file is not extents " 493 "based file [ino:donor %lu]\n", donor_inode->i_ino); 494 return -EOPNOTSUPP; 495 } 496 497 if ((!orig_inode->i_size) || (!donor_inode->i_size)) { 498 ext4_debug("ext4 move extent: File size is 0 byte\n"); 499 return -EINVAL; 500 } 501 502 /* Start offset should be same */ 503 if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) != 504 (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) { 505 ext4_debug("ext4 move extent: orig and donor's start " 506 "offsets are not aligned [ino:orig %lu, donor %lu]\n", 507 orig_inode->i_ino, donor_inode->i_ino); 508 return -EINVAL; 509 } 510 511 if ((orig_start >= EXT_MAX_BLOCKS) || 512 (donor_start >= EXT_MAX_BLOCKS) || 513 (*len > EXT_MAX_BLOCKS) || 514 (donor_start + *len >= EXT_MAX_BLOCKS) || 515 (orig_start + *len >= EXT_MAX_BLOCKS)) { 516 ext4_debug("ext4 move extent: Can't handle over [%u] blocks " 517 "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS, 518 orig_inode->i_ino, donor_inode->i_ino); 519 return -EINVAL; 520 } 521 if (orig_eof <= orig_start) 522 *len = 0; 523 else if (orig_eof < orig_start + *len - 1) 524 *len = orig_eof - orig_start; 525 if (donor_eof <= donor_start) 526 *len = 0; 527 else if (donor_eof < donor_start + *len - 1) 528 *len = donor_eof - donor_start; 529 if (!*len) { 530 ext4_debug("ext4 move extent: len should not be 0 " 531 "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino, 532 donor_inode->i_ino); 533 return -EINVAL; 534 } 535 536 return 0; 537 } 538 539 /** 540 * ext4_move_extents - Exchange the specified range of a file 541 * 542 * @o_filp: file structure of the original file 543 * @d_filp: file structure of the donor file 544 * @orig_blk: start offset in block for orig 545 * @donor_blk: start offset in block for donor 546 * @len: the number of blocks to be moved 547 * @moved_len: moved block length 548 * 549 * This function returns 0 and moved block length is set in moved_len 550 * if succeed, otherwise returns error value. 551 * 552 */ 553 int 554 ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk, 555 __u64 donor_blk, __u64 len, __u64 *moved_len) 556 { 557 struct inode *orig_inode = file_inode(o_filp); 558 struct inode *donor_inode = file_inode(d_filp); 559 struct ext4_ext_path *path = NULL; 560 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 561 ext4_lblk_t o_end, o_start = orig_blk; 562 ext4_lblk_t d_start = donor_blk; 563 int ret; 564 565 if (orig_inode->i_sb != donor_inode->i_sb) { 566 ext4_debug("ext4 move extent: The argument files " 567 "should be in same FS [ino:orig %lu, donor %lu]\n", 568 orig_inode->i_ino, donor_inode->i_ino); 569 return -EINVAL; 570 } 571 572 /* orig and donor should be different inodes */ 573 if (orig_inode == donor_inode) { 574 ext4_debug("ext4 move extent: The argument files should not " 575 "be same inode [ino:orig %lu, donor %lu]\n", 576 orig_inode->i_ino, donor_inode->i_ino); 577 return -EINVAL; 578 } 579 580 /* Regular file check */ 581 if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) { 582 ext4_debug("ext4 move extent: The argument files should be " 583 "regular file [ino:orig %lu, donor %lu]\n", 584 orig_inode->i_ino, donor_inode->i_ino); 585 return -EINVAL; 586 } 587 588 /* TODO: it's not obvious how to swap blocks for inodes with full 589 journaling enabled */ 590 if (ext4_should_journal_data(orig_inode) || 591 ext4_should_journal_data(donor_inode)) { 592 ext4_msg(orig_inode->i_sb, KERN_ERR, 593 "Online defrag not supported with data journaling"); 594 return -EOPNOTSUPP; 595 } 596 597 if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) { 598 ext4_msg(orig_inode->i_sb, KERN_ERR, 599 "Online defrag not supported for encrypted files"); 600 return -EOPNOTSUPP; 601 } 602 603 /* Protect orig and donor inodes against a truncate */ 604 lock_two_nondirectories(orig_inode, donor_inode); 605 606 /* Wait for all existing dio workers */ 607 inode_dio_wait(orig_inode); 608 inode_dio_wait(donor_inode); 609 610 /* Protect extent tree against block allocations via delalloc */ 611 ext4_double_down_write_data_sem(orig_inode, donor_inode); 612 /* Check the filesystem environment whether move_extent can be done */ 613 ret = mext_check_arguments(orig_inode, donor_inode, orig_blk, 614 donor_blk, &len); 615 if (ret) 616 goto out; 617 o_end = o_start + len; 618 619 *moved_len = 0; 620 while (o_start < o_end) { 621 struct ext4_extent *ex; 622 ext4_lblk_t cur_blk, next_blk; 623 pgoff_t orig_page_index, donor_page_index; 624 int offset_in_page; 625 int unwritten, cur_len; 626 627 ret = get_ext_path(orig_inode, o_start, &path); 628 if (ret) 629 goto out; 630 ex = path[path->p_depth].p_ext; 631 cur_blk = le32_to_cpu(ex->ee_block); 632 cur_len = ext4_ext_get_actual_len(ex); 633 /* Check hole before the start pos */ 634 if (cur_blk + cur_len - 1 < o_start) { 635 next_blk = ext4_ext_next_allocated_block(path); 636 if (next_blk == EXT_MAX_BLOCKS) { 637 ret = -ENODATA; 638 goto out; 639 } 640 d_start += next_blk - o_start; 641 o_start = next_blk; 642 continue; 643 /* Check hole after the start pos */ 644 } else if (cur_blk > o_start) { 645 /* Skip hole */ 646 d_start += cur_blk - o_start; 647 o_start = cur_blk; 648 /* Extent inside requested range ?*/ 649 if (cur_blk >= o_end) 650 goto out; 651 } else { /* in_range(o_start, o_blk, o_len) */ 652 cur_len += cur_blk - o_start; 653 } 654 unwritten = ext4_ext_is_unwritten(ex); 655 if (o_end - o_start < cur_len) 656 cur_len = o_end - o_start; 657 658 orig_page_index = o_start >> (PAGE_SHIFT - 659 orig_inode->i_blkbits); 660 donor_page_index = d_start >> (PAGE_SHIFT - 661 donor_inode->i_blkbits); 662 offset_in_page = o_start % blocks_per_page; 663 if (cur_len > blocks_per_page - offset_in_page) 664 cur_len = blocks_per_page - offset_in_page; 665 /* 666 * Up semaphore to avoid following problems: 667 * a. transaction deadlock among ext4_journal_start, 668 * ->write_begin via pagefault, and jbd2_journal_commit 669 * b. racing with ->read_folio, ->write_begin, and 670 * ext4_get_block in move_extent_per_page 671 */ 672 ext4_double_up_write_data_sem(orig_inode, donor_inode); 673 /* Swap original branches with new branches */ 674 *moved_len += move_extent_per_page(o_filp, donor_inode, 675 orig_page_index, donor_page_index, 676 offset_in_page, cur_len, 677 unwritten, &ret); 678 ext4_double_down_write_data_sem(orig_inode, donor_inode); 679 if (ret < 0) 680 break; 681 o_start += cur_len; 682 d_start += cur_len; 683 } 684 685 out: 686 if (*moved_len) { 687 ext4_discard_preallocations(orig_inode); 688 ext4_discard_preallocations(donor_inode); 689 } 690 691 ext4_free_ext_path(path); 692 ext4_double_up_write_data_sem(orig_inode, donor_inode); 693 unlock_two_nondirectories(orig_inode, donor_inode); 694 695 return ret; 696 } 697