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); 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 } 709