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_page_double_lock - Grab and lock pages on both @inode1 and @inode2 114 * 115 * @inode1: the inode structure 116 * @inode2: the inode structure 117 * @index1: page index 118 * @index2: page index 119 * @page: result page vector 120 * 121 * Grab two locked pages for inode's by inode order 122 */ 123 static int 124 mext_page_double_lock(struct inode *inode1, struct inode *inode2, 125 pgoff_t index1, pgoff_t index2, struct page *page[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 page[0] = grab_cache_page_write_begin(mapping[0], index1); 142 if (!page[0]) { 143 memalloc_nofs_restore(flags); 144 return -ENOMEM; 145 } 146 147 page[1] = grab_cache_page_write_begin(mapping[1], index2); 148 memalloc_nofs_restore(flags); 149 if (!page[1]) { 150 unlock_page(page[0]); 151 put_page(page[0]); 152 return -ENOMEM; 153 } 154 /* 155 * grab_cache_page_write_begin() may not wait on page's writeback if 156 * BDI not demand that. But it is reasonable to be very conservative 157 * here and explicitly wait on page's writeback 158 */ 159 wait_on_page_writeback(page[0]); 160 wait_on_page_writeback(page[1]); 161 if (inode1 > inode2) 162 swap(page[0], page[1]); 163 164 return 0; 165 } 166 167 /* Force page buffers uptodate w/o dropping page's lock */ 168 static int 169 mext_page_mkuptodate(struct page *page, unsigned from, unsigned to) 170 { 171 struct inode *inode = page->mapping->host; 172 sector_t block; 173 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; 174 unsigned int blocksize, block_start, block_end; 175 int i, err, nr = 0, partial = 0; 176 BUG_ON(!PageLocked(page)); 177 BUG_ON(PageWriteback(page)); 178 179 if (PageUptodate(page)) 180 return 0; 181 182 blocksize = i_blocksize(inode); 183 if (!page_has_buffers(page)) 184 create_empty_buffers(page, blocksize, 0); 185 186 head = page_buffers(page); 187 block = (sector_t)page->index << (PAGE_SHIFT - inode->i_blkbits); 188 for (bh = head, block_start = 0; bh != head || !block_start; 189 block++, block_start = block_end, bh = bh->b_this_page) { 190 block_end = block_start + blocksize; 191 if (block_end <= from || block_start >= to) { 192 if (!buffer_uptodate(bh)) 193 partial = 1; 194 continue; 195 } 196 if (buffer_uptodate(bh)) 197 continue; 198 if (!buffer_mapped(bh)) { 199 err = ext4_get_block(inode, block, bh, 0); 200 if (err) { 201 SetPageError(page); 202 return err; 203 } 204 if (!buffer_mapped(bh)) { 205 zero_user(page, 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 SetPageUptodate(page); 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 page *pagep[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_page_double_lock(orig_inode, donor_inode, orig_page_offset, 306 donor_page_offset, pagep); 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 if (unwritten) { 317 ext4_double_down_write_data_sem(orig_inode, donor_inode); 318 /* If any of extents in range became initialized we have to 319 * fallback to data copying */ 320 unwritten = mext_check_coverage(orig_inode, orig_blk_offset, 321 block_len_in_page, 1, err); 322 if (*err) 323 goto drop_data_sem; 324 325 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset, 326 block_len_in_page, 1, err); 327 if (*err) 328 goto drop_data_sem; 329 330 if (!unwritten) { 331 ext4_double_up_write_data_sem(orig_inode, donor_inode); 332 goto data_copy; 333 } 334 if ((page_has_private(pagep[0]) && 335 !try_to_release_page(pagep[0], 0)) || 336 (page_has_private(pagep[1]) && 337 !try_to_release_page(pagep[1], 0))) { 338 *err = -EBUSY; 339 goto drop_data_sem; 340 } 341 replaced_count = ext4_swap_extents(handle, orig_inode, 342 donor_inode, orig_blk_offset, 343 donor_blk_offset, 344 block_len_in_page, 1, err); 345 drop_data_sem: 346 ext4_double_up_write_data_sem(orig_inode, donor_inode); 347 goto unlock_pages; 348 } 349 data_copy: 350 *err = mext_page_mkuptodate(pagep[0], from, from + replaced_size); 351 if (*err) 352 goto unlock_pages; 353 354 /* At this point all buffers in range are uptodate, old mapping layout 355 * is no longer required, try to drop it now. */ 356 if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) || 357 (page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) { 358 *err = -EBUSY; 359 goto unlock_pages; 360 } 361 ext4_double_down_write_data_sem(orig_inode, donor_inode); 362 replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, 363 orig_blk_offset, donor_blk_offset, 364 block_len_in_page, 1, err); 365 ext4_double_up_write_data_sem(orig_inode, donor_inode); 366 if (*err) { 367 if (replaced_count) { 368 block_len_in_page = replaced_count; 369 replaced_size = 370 block_len_in_page << orig_inode->i_blkbits; 371 } else 372 goto unlock_pages; 373 } 374 /* Perform all necessary steps similar write_begin()/write_end() 375 * but keeping in mind that i_size will not change */ 376 if (!page_has_buffers(pagep[0])) 377 create_empty_buffers(pagep[0], 1 << orig_inode->i_blkbits, 0); 378 bh = page_buffers(pagep[0]); 379 for (i = 0; i < data_offset_in_page; i++) 380 bh = bh->b_this_page; 381 for (i = 0; i < block_len_in_page; i++) { 382 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); 383 if (*err < 0) 384 break; 385 bh = bh->b_this_page; 386 } 387 if (!*err) 388 *err = block_commit_write(pagep[0], from, from + replaced_size); 389 390 if (unlikely(*err < 0)) 391 goto repair_branches; 392 393 /* Even in case of data=writeback it is reasonable to pin 394 * inode to transaction, to prevent unexpected data loss */ 395 *err = ext4_jbd2_inode_add_write(handle, orig_inode, 396 (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size); 397 398 unlock_pages: 399 unlock_page(pagep[0]); 400 put_page(pagep[0]); 401 unlock_page(pagep[1]); 402 put_page(pagep[1]); 403 stop_journal: 404 ext4_journal_stop(handle); 405 if (*err == -ENOSPC && 406 ext4_should_retry_alloc(sb, &retries)) 407 goto again; 408 /* Buffer was busy because probably is pinned to journal transaction, 409 * force transaction commit may help to free it. */ 410 if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal && 411 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal)) 412 goto again; 413 return replaced_count; 414 415 repair_branches: 416 /* 417 * This should never ever happen! 418 * Extents are swapped already, but we are not able to copy data. 419 * Try to swap extents to it's original places 420 */ 421 ext4_double_down_write_data_sem(orig_inode, donor_inode); 422 replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode, 423 orig_blk_offset, donor_blk_offset, 424 block_len_in_page, 0, &err2); 425 ext4_double_up_write_data_sem(orig_inode, donor_inode); 426 if (replaced_count != block_len_in_page) { 427 ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset), 428 EIO, "Unable to copy data block," 429 " data will be lost."); 430 *err = -EIO; 431 } 432 replaced_count = 0; 433 goto unlock_pages; 434 } 435 436 /** 437 * mext_check_arguments - Check whether move extent can be done 438 * 439 * @orig_inode: original inode 440 * @donor_inode: donor inode 441 * @orig_start: logical start offset in block for orig 442 * @donor_start: logical start offset in block for donor 443 * @len: the number of blocks to be moved 444 * 445 * Check the arguments of ext4_move_extents() whether the files can be 446 * exchanged with each other. 447 * Return 0 on success, or a negative error value on failure. 448 */ 449 static int 450 mext_check_arguments(struct inode *orig_inode, 451 struct inode *donor_inode, __u64 orig_start, 452 __u64 donor_start, __u64 *len) 453 { 454 __u64 orig_eof, donor_eof; 455 unsigned int blkbits = orig_inode->i_blkbits; 456 unsigned int blocksize = 1 << blkbits; 457 458 orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits; 459 donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits; 460 461 462 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { 463 ext4_debug("ext4 move extent: suid or sgid is set" 464 " to donor file [ino:orig %lu, donor %lu]\n", 465 orig_inode->i_ino, donor_inode->i_ino); 466 return -EINVAL; 467 } 468 469 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) 470 return -EPERM; 471 472 /* Ext4 move extent does not support swap files */ 473 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { 474 ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n", 475 orig_inode->i_ino, donor_inode->i_ino); 476 return -ETXTBSY; 477 } 478 479 if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) { 480 ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n", 481 orig_inode->i_ino, donor_inode->i_ino); 482 return -EOPNOTSUPP; 483 } 484 485 /* Ext4 move extent supports only extent based file */ 486 if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) { 487 ext4_debug("ext4 move extent: orig file is not extents " 488 "based file [ino:orig %lu]\n", orig_inode->i_ino); 489 return -EOPNOTSUPP; 490 } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) { 491 ext4_debug("ext4 move extent: donor file is not extents " 492 "based file [ino:donor %lu]\n", donor_inode->i_ino); 493 return -EOPNOTSUPP; 494 } 495 496 if ((!orig_inode->i_size) || (!donor_inode->i_size)) { 497 ext4_debug("ext4 move extent: File size is 0 byte\n"); 498 return -EINVAL; 499 } 500 501 /* Start offset should be same */ 502 if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) != 503 (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) { 504 ext4_debug("ext4 move extent: orig and donor's start " 505 "offsets are not aligned [ino:orig %lu, donor %lu]\n", 506 orig_inode->i_ino, donor_inode->i_ino); 507 return -EINVAL; 508 } 509 510 if ((orig_start >= EXT_MAX_BLOCKS) || 511 (donor_start >= EXT_MAX_BLOCKS) || 512 (*len > EXT_MAX_BLOCKS) || 513 (donor_start + *len >= EXT_MAX_BLOCKS) || 514 (orig_start + *len >= EXT_MAX_BLOCKS)) { 515 ext4_debug("ext4 move extent: Can't handle over [%u] blocks " 516 "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS, 517 orig_inode->i_ino, donor_inode->i_ino); 518 return -EINVAL; 519 } 520 if (orig_eof <= orig_start) 521 *len = 0; 522 else if (orig_eof < orig_start + *len - 1) 523 *len = orig_eof - orig_start; 524 if (donor_eof <= donor_start) 525 *len = 0; 526 else if (donor_eof < donor_start + *len - 1) 527 *len = donor_eof - donor_start; 528 if (!*len) { 529 ext4_debug("ext4 move extent: len should not be 0 " 530 "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino, 531 donor_inode->i_ino); 532 return -EINVAL; 533 } 534 535 return 0; 536 } 537 538 /** 539 * ext4_move_extents - Exchange the specified range of a file 540 * 541 * @o_filp: file structure of the original file 542 * @d_filp: file structure of the donor file 543 * @orig_blk: start offset in block for orig 544 * @donor_blk: start offset in block for donor 545 * @len: the number of blocks to be moved 546 * @moved_len: moved block length 547 * 548 * This function returns 0 and moved block length is set in moved_len 549 * if succeed, otherwise returns error value. 550 * 551 */ 552 int 553 ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk, 554 __u64 donor_blk, __u64 len, __u64 *moved_len) 555 { 556 struct inode *orig_inode = file_inode(o_filp); 557 struct inode *donor_inode = file_inode(d_filp); 558 struct ext4_ext_path *path = NULL; 559 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 560 ext4_lblk_t o_end, o_start = orig_blk; 561 ext4_lblk_t d_start = donor_blk; 562 int ret; 563 564 if (orig_inode->i_sb != donor_inode->i_sb) { 565 ext4_debug("ext4 move extent: The argument files " 566 "should be in same FS [ino:orig %lu, donor %lu]\n", 567 orig_inode->i_ino, donor_inode->i_ino); 568 return -EINVAL; 569 } 570 571 /* orig and donor should be different inodes */ 572 if (orig_inode == donor_inode) { 573 ext4_debug("ext4 move extent: The argument files should not " 574 "be same inode [ino:orig %lu, donor %lu]\n", 575 orig_inode->i_ino, donor_inode->i_ino); 576 return -EINVAL; 577 } 578 579 /* Regular file check */ 580 if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) { 581 ext4_debug("ext4 move extent: The argument files should be " 582 "regular file [ino:orig %lu, donor %lu]\n", 583 orig_inode->i_ino, donor_inode->i_ino); 584 return -EINVAL; 585 } 586 587 /* TODO: it's not obvious how to swap blocks for inodes with full 588 journaling enabled */ 589 if (ext4_should_journal_data(orig_inode) || 590 ext4_should_journal_data(donor_inode)) { 591 ext4_msg(orig_inode->i_sb, KERN_ERR, 592 "Online defrag not supported with data journaling"); 593 return -EOPNOTSUPP; 594 } 595 596 if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) { 597 ext4_msg(orig_inode->i_sb, KERN_ERR, 598 "Online defrag not supported for encrypted files"); 599 return -EOPNOTSUPP; 600 } 601 602 /* Protect orig and donor inodes against a truncate */ 603 lock_two_nondirectories(orig_inode, donor_inode); 604 605 /* Wait for all existing dio workers */ 606 inode_dio_wait(orig_inode); 607 inode_dio_wait(donor_inode); 608 609 /* Protect extent tree against block allocations via delalloc */ 610 ext4_double_down_write_data_sem(orig_inode, donor_inode); 611 /* Check the filesystem environment whether move_extent can be done */ 612 ret = mext_check_arguments(orig_inode, donor_inode, orig_blk, 613 donor_blk, &len); 614 if (ret) 615 goto out; 616 o_end = o_start + len; 617 618 while (o_start < o_end) { 619 struct ext4_extent *ex; 620 ext4_lblk_t cur_blk, next_blk; 621 pgoff_t orig_page_index, donor_page_index; 622 int offset_in_page; 623 int unwritten, cur_len; 624 625 ret = get_ext_path(orig_inode, o_start, &path); 626 if (ret) 627 goto out; 628 ex = path[path->p_depth].p_ext; 629 cur_blk = le32_to_cpu(ex->ee_block); 630 cur_len = ext4_ext_get_actual_len(ex); 631 /* Check hole before the start pos */ 632 if (cur_blk + cur_len - 1 < o_start) { 633 next_blk = ext4_ext_next_allocated_block(path); 634 if (next_blk == EXT_MAX_BLOCKS) { 635 ret = -ENODATA; 636 goto out; 637 } 638 d_start += next_blk - o_start; 639 o_start = next_blk; 640 continue; 641 /* Check hole after the start pos */ 642 } else if (cur_blk > o_start) { 643 /* Skip hole */ 644 d_start += cur_blk - o_start; 645 o_start = cur_blk; 646 /* Extent inside requested range ?*/ 647 if (cur_blk >= o_end) 648 goto out; 649 } else { /* in_range(o_start, o_blk, o_len) */ 650 cur_len += cur_blk - o_start; 651 } 652 unwritten = ext4_ext_is_unwritten(ex); 653 if (o_end - o_start < cur_len) 654 cur_len = o_end - o_start; 655 656 orig_page_index = o_start >> (PAGE_SHIFT - 657 orig_inode->i_blkbits); 658 donor_page_index = d_start >> (PAGE_SHIFT - 659 donor_inode->i_blkbits); 660 offset_in_page = o_start % blocks_per_page; 661 if (cur_len > blocks_per_page - offset_in_page) 662 cur_len = blocks_per_page - offset_in_page; 663 /* 664 * Up semaphore to avoid following problems: 665 * a. transaction deadlock among ext4_journal_start, 666 * ->write_begin via pagefault, and jbd2_journal_commit 667 * b. racing with ->read_folio, ->write_begin, and 668 * ext4_get_block in move_extent_per_page 669 */ 670 ext4_double_up_write_data_sem(orig_inode, donor_inode); 671 /* Swap original branches with new branches */ 672 move_extent_per_page(o_filp, donor_inode, 673 orig_page_index, donor_page_index, 674 offset_in_page, cur_len, 675 unwritten, &ret); 676 ext4_double_down_write_data_sem(orig_inode, donor_inode); 677 if (ret < 0) 678 break; 679 o_start += cur_len; 680 d_start += cur_len; 681 } 682 *moved_len = o_start - orig_blk; 683 if (*moved_len > len) 684 *moved_len = len; 685 686 out: 687 if (*moved_len) { 688 ext4_discard_preallocations(orig_inode, 0); 689 ext4_discard_preallocations(donor_inode, 0); 690 } 691 692 ext4_free_ext_path(path); 693 ext4_double_up_write_data_sem(orig_inode, donor_inode); 694 unlock_two_nondirectories(orig_inode, donor_inode); 695 696 return ret; 697 } 698