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; 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_meta_trans_blocks(orig_inode, block_len_in_page, 284 block_len_in_page) * 2; 285 handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks); 286 if (IS_ERR(handle)) { 287 *err = PTR_ERR(handle); 288 return 0; 289 } 290 291 orig_blk_offset = orig_page_offset * blocks_per_page + 292 data_offset_in_page; 293 294 donor_blk_offset = donor_page_offset * blocks_per_page + 295 data_offset_in_page; 296 297 /* Calculate data_size */ 298 if ((orig_blk_offset + block_len_in_page - 1) == 299 ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) { 300 /* Replace the last block */ 301 tmp_data_size = orig_inode->i_size & (blocksize - 1); 302 /* 303 * If data_size equal zero, it shows data_size is multiples of 304 * blocksize. So we set appropriate value. 305 */ 306 if (tmp_data_size == 0) 307 tmp_data_size = blocksize; 308 309 data_size = tmp_data_size + 310 ((block_len_in_page - 1) << orig_inode->i_blkbits); 311 } else 312 data_size = block_len_in_page << orig_inode->i_blkbits; 313 314 replaced_size = data_size; 315 316 *err = mext_folio_double_lock(orig_inode, donor_inode, orig_page_offset, 317 donor_page_offset, folio); 318 if (unlikely(*err < 0)) 319 goto stop_journal; 320 /* 321 * If orig extent was unwritten it can become initialized 322 * at any time after i_data_sem was dropped, in order to 323 * serialize with delalloc we have recheck extent while we 324 * hold page's lock, if it is still the case data copy is not 325 * necessary, just swap data blocks between orig and donor. 326 */ 327 if (unwritten) { 328 ext4_double_down_write_data_sem(orig_inode, donor_inode); 329 /* If any of extents in range became initialized we have to 330 * fallback to data copying */ 331 unwritten = mext_check_coverage(orig_inode, orig_blk_offset, 332 block_len_in_page, 1, err); 333 if (*err) 334 goto drop_data_sem; 335 336 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset, 337 block_len_in_page, 1, err); 338 if (*err) 339 goto drop_data_sem; 340 341 if (!unwritten) { 342 ext4_double_up_write_data_sem(orig_inode, donor_inode); 343 goto data_copy; 344 } 345 if (!filemap_release_folio(folio[0], 0) || 346 !filemap_release_folio(folio[1], 0)) { 347 *err = -EBUSY; 348 goto drop_data_sem; 349 } 350 replaced_count = ext4_swap_extents(handle, orig_inode, 351 donor_inode, orig_blk_offset, 352 donor_blk_offset, 353 block_len_in_page, 1, err); 354 drop_data_sem: 355 ext4_double_up_write_data_sem(orig_inode, donor_inode); 356 goto unlock_folios; 357 } 358 data_copy: 359 from = offset_in_folio(folio[0], 360 orig_blk_offset << orig_inode->i_blkbits); 361 *err = mext_page_mkuptodate(folio[0], from, from + replaced_size); 362 if (*err) 363 goto unlock_folios; 364 365 /* At this point all buffers in range are uptodate, old mapping layout 366 * is no longer required, try to drop it now. */ 367 if (!filemap_release_folio(folio[0], 0) || 368 !filemap_release_folio(folio[1], 0)) { 369 *err = -EBUSY; 370 goto unlock_folios; 371 } 372 ext4_double_down_write_data_sem(orig_inode, donor_inode); 373 replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, 374 orig_blk_offset, donor_blk_offset, 375 block_len_in_page, 1, err); 376 ext4_double_up_write_data_sem(orig_inode, donor_inode); 377 if (*err) { 378 if (replaced_count) { 379 block_len_in_page = replaced_count; 380 replaced_size = 381 block_len_in_page << orig_inode->i_blkbits; 382 } else 383 goto unlock_folios; 384 } 385 /* Perform all necessary steps similar write_begin()/write_end() 386 * but keeping in mind that i_size will not change */ 387 bh = folio_buffers(folio[0]); 388 if (!bh) 389 bh = create_empty_buffers(folio[0], 390 1 << orig_inode->i_blkbits, 0); 391 for (i = 0; i < from >> orig_inode->i_blkbits; i++) 392 bh = bh->b_this_page; 393 for (i = 0; i < block_len_in_page; i++) { 394 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); 395 if (*err < 0) 396 goto repair_branches; 397 bh = bh->b_this_page; 398 } 399 400 block_commit_write(folio[0], from, from + replaced_size); 401 402 /* Even in case of data=writeback it is reasonable to pin 403 * inode to transaction, to prevent unexpected data loss */ 404 *err = ext4_jbd2_inode_add_write(handle, orig_inode, 405 (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size); 406 407 unlock_folios: 408 folio_unlock(folio[0]); 409 folio_put(folio[0]); 410 folio_unlock(folio[1]); 411 folio_put(folio[1]); 412 stop_journal: 413 ext4_journal_stop(handle); 414 if (*err == -ENOSPC && 415 ext4_should_retry_alloc(sb, &retries)) 416 goto again; 417 /* Buffer was busy because probably is pinned to journal transaction, 418 * force transaction commit may help to free it. */ 419 if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal && 420 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal)) 421 goto again; 422 return replaced_count; 423 424 repair_branches: 425 /* 426 * This should never ever happen! 427 * Extents are swapped already, but we are not able to copy data. 428 * Try to swap extents to it's original places 429 */ 430 ext4_double_down_write_data_sem(orig_inode, donor_inode); 431 replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode, 432 orig_blk_offset, donor_blk_offset, 433 block_len_in_page, 0, &err2); 434 ext4_double_up_write_data_sem(orig_inode, donor_inode); 435 if (replaced_count != block_len_in_page) { 436 ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset), 437 EIO, "Unable to copy data block," 438 " data will be lost."); 439 *err = -EIO; 440 } 441 replaced_count = 0; 442 goto unlock_folios; 443 } 444 445 /** 446 * mext_check_arguments - Check whether move extent can be done 447 * 448 * @orig_inode: original inode 449 * @donor_inode: donor inode 450 * @orig_start: logical start offset in block for orig 451 * @donor_start: logical start offset in block for donor 452 * @len: the number of blocks to be moved 453 * 454 * Check the arguments of ext4_move_extents() whether the files can be 455 * exchanged with each other. 456 * Return 0 on success, or a negative error value on failure. 457 */ 458 static int 459 mext_check_arguments(struct inode *orig_inode, 460 struct inode *donor_inode, __u64 orig_start, 461 __u64 donor_start, __u64 *len) 462 { 463 __u64 orig_eof, donor_eof; 464 unsigned int blkbits = orig_inode->i_blkbits; 465 unsigned int blocksize = 1 << blkbits; 466 467 orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits; 468 donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits; 469 470 471 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { 472 ext4_debug("ext4 move extent: suid or sgid is set" 473 " to donor file [ino:orig %lu, donor %lu]\n", 474 orig_inode->i_ino, donor_inode->i_ino); 475 return -EINVAL; 476 } 477 478 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) 479 return -EPERM; 480 481 /* Ext4 move extent does not support swap files */ 482 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { 483 ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n", 484 orig_inode->i_ino, donor_inode->i_ino); 485 return -ETXTBSY; 486 } 487 488 if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) { 489 ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n", 490 orig_inode->i_ino, donor_inode->i_ino); 491 return -EOPNOTSUPP; 492 } 493 494 /* Ext4 move extent supports only extent based file */ 495 if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) { 496 ext4_debug("ext4 move extent: orig file is not extents " 497 "based file [ino:orig %lu]\n", orig_inode->i_ino); 498 return -EOPNOTSUPP; 499 } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) { 500 ext4_debug("ext4 move extent: donor file is not extents " 501 "based file [ino:donor %lu]\n", donor_inode->i_ino); 502 return -EOPNOTSUPP; 503 } 504 505 if ((!orig_inode->i_size) || (!donor_inode->i_size)) { 506 ext4_debug("ext4 move extent: File size is 0 byte\n"); 507 return -EINVAL; 508 } 509 510 /* Start offset should be same */ 511 if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) != 512 (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) { 513 ext4_debug("ext4 move extent: orig and donor's start " 514 "offsets are not aligned [ino:orig %lu, donor %lu]\n", 515 orig_inode->i_ino, donor_inode->i_ino); 516 return -EINVAL; 517 } 518 519 if ((orig_start >= EXT_MAX_BLOCKS) || 520 (donor_start >= EXT_MAX_BLOCKS) || 521 (*len > EXT_MAX_BLOCKS) || 522 (donor_start + *len >= EXT_MAX_BLOCKS) || 523 (orig_start + *len >= EXT_MAX_BLOCKS)) { 524 ext4_debug("ext4 move extent: Can't handle over [%u] blocks " 525 "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS, 526 orig_inode->i_ino, donor_inode->i_ino); 527 return -EINVAL; 528 } 529 if (orig_eof <= orig_start) 530 *len = 0; 531 else if (orig_eof < orig_start + *len - 1) 532 *len = orig_eof - orig_start; 533 if (donor_eof <= donor_start) 534 *len = 0; 535 else if (donor_eof < donor_start + *len - 1) 536 *len = donor_eof - donor_start; 537 if (!*len) { 538 ext4_debug("ext4 move extent: len should not be 0 " 539 "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino, 540 donor_inode->i_ino); 541 return -EINVAL; 542 } 543 544 return 0; 545 } 546 547 /** 548 * ext4_move_extents - Exchange the specified range of a file 549 * 550 * @o_filp: file structure of the original file 551 * @d_filp: file structure of the donor file 552 * @orig_blk: start offset in block for orig 553 * @donor_blk: start offset in block for donor 554 * @len: the number of blocks to be moved 555 * @moved_len: moved block length 556 * 557 * This function returns 0 and moved block length is set in moved_len 558 * if succeed, otherwise returns error value. 559 * 560 */ 561 int 562 ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk, 563 __u64 donor_blk, __u64 len, __u64 *moved_len) 564 { 565 struct inode *orig_inode = file_inode(o_filp); 566 struct inode *donor_inode = file_inode(d_filp); 567 struct ext4_ext_path *path = NULL; 568 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 569 ext4_lblk_t o_end, o_start = orig_blk; 570 ext4_lblk_t d_start = donor_blk; 571 int ret; 572 573 if (orig_inode->i_sb != donor_inode->i_sb) { 574 ext4_debug("ext4 move extent: The argument files " 575 "should be in same FS [ino:orig %lu, donor %lu]\n", 576 orig_inode->i_ino, donor_inode->i_ino); 577 return -EINVAL; 578 } 579 580 /* orig and donor should be different inodes */ 581 if (orig_inode == donor_inode) { 582 ext4_debug("ext4 move extent: The argument files should not " 583 "be same inode [ino:orig %lu, donor %lu]\n", 584 orig_inode->i_ino, donor_inode->i_ino); 585 return -EINVAL; 586 } 587 588 /* Regular file check */ 589 if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) { 590 ext4_debug("ext4 move extent: The argument files should be " 591 "regular file [ino:orig %lu, donor %lu]\n", 592 orig_inode->i_ino, donor_inode->i_ino); 593 return -EINVAL; 594 } 595 596 /* TODO: it's not obvious how to swap blocks for inodes with full 597 journaling enabled */ 598 if (ext4_should_journal_data(orig_inode) || 599 ext4_should_journal_data(donor_inode)) { 600 ext4_msg(orig_inode->i_sb, KERN_ERR, 601 "Online defrag not supported with data journaling"); 602 return -EOPNOTSUPP; 603 } 604 605 if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) { 606 ext4_msg(orig_inode->i_sb, KERN_ERR, 607 "Online defrag not supported for encrypted files"); 608 return -EOPNOTSUPP; 609 } 610 611 /* Protect orig and donor inodes against a truncate */ 612 lock_two_nondirectories(orig_inode, donor_inode); 613 614 /* Wait for all existing dio workers */ 615 inode_dio_wait(orig_inode); 616 inode_dio_wait(donor_inode); 617 618 /* Protect extent tree against block allocations via delalloc */ 619 ext4_double_down_write_data_sem(orig_inode, donor_inode); 620 /* Check the filesystem environment whether move_extent can be done */ 621 ret = mext_check_arguments(orig_inode, donor_inode, orig_blk, 622 donor_blk, &len); 623 if (ret) 624 goto out; 625 o_end = o_start + len; 626 627 *moved_len = 0; 628 while (o_start < o_end) { 629 struct ext4_extent *ex; 630 ext4_lblk_t cur_blk, next_blk; 631 pgoff_t orig_page_index, donor_page_index; 632 int offset_in_page; 633 int unwritten, cur_len; 634 635 path = get_ext_path(orig_inode, o_start, path); 636 if (IS_ERR(path)) { 637 ret = PTR_ERR(path); 638 goto out; 639 } 640 ex = path[path->p_depth].p_ext; 641 cur_blk = le32_to_cpu(ex->ee_block); 642 cur_len = ext4_ext_get_actual_len(ex); 643 /* Check hole before the start pos */ 644 if (cur_blk + cur_len - 1 < o_start) { 645 next_blk = ext4_ext_next_allocated_block(path); 646 if (next_blk == EXT_MAX_BLOCKS) { 647 ret = -ENODATA; 648 goto out; 649 } 650 d_start += next_blk - o_start; 651 o_start = next_blk; 652 continue; 653 /* Check hole after the start pos */ 654 } else if (cur_blk > o_start) { 655 /* Skip hole */ 656 d_start += cur_blk - o_start; 657 o_start = cur_blk; 658 /* Extent inside requested range ?*/ 659 if (cur_blk >= o_end) 660 goto out; 661 } else { /* in_range(o_start, o_blk, o_len) */ 662 cur_len += cur_blk - o_start; 663 } 664 unwritten = ext4_ext_is_unwritten(ex); 665 if (o_end - o_start < cur_len) 666 cur_len = o_end - o_start; 667 668 orig_page_index = o_start >> (PAGE_SHIFT - 669 orig_inode->i_blkbits); 670 donor_page_index = d_start >> (PAGE_SHIFT - 671 donor_inode->i_blkbits); 672 offset_in_page = o_start % blocks_per_page; 673 if (cur_len > blocks_per_page - offset_in_page) 674 cur_len = blocks_per_page - offset_in_page; 675 /* 676 * Up semaphore to avoid following problems: 677 * a. transaction deadlock among ext4_journal_start, 678 * ->write_begin via pagefault, and jbd2_journal_commit 679 * b. racing with ->read_folio, ->write_begin, and 680 * ext4_get_block in move_extent_per_page 681 */ 682 ext4_double_up_write_data_sem(orig_inode, donor_inode); 683 /* Swap original branches with new branches */ 684 *moved_len += move_extent_per_page(o_filp, donor_inode, 685 orig_page_index, donor_page_index, 686 offset_in_page, cur_len, 687 unwritten, &ret); 688 ext4_double_down_write_data_sem(orig_inode, donor_inode); 689 if (ret < 0) 690 break; 691 o_start += cur_len; 692 d_start += cur_len; 693 } 694 695 out: 696 if (*moved_len) { 697 ext4_discard_preallocations(orig_inode); 698 ext4_discard_preallocations(donor_inode); 699 } 700 701 ext4_free_ext_path(path); 702 ext4_double_up_write_data_sem(orig_inode, donor_inode); 703 unlock_two_nondirectories(orig_inode, donor_inode); 704 705 return ret; 706 } 707