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 return 0; 40 } 41 42 /** 43 * ext4_double_down_write_data_sem() - write lock two inodes's i_data_sem 44 * @first: inode to be locked 45 * @second: inode to be locked 46 * 47 * Acquire write lock of i_data_sem of the two inodes 48 */ 49 void 50 ext4_double_down_write_data_sem(struct inode *first, struct inode *second) 51 { 52 if (first < second) { 53 down_write(&EXT4_I(first)->i_data_sem); 54 down_write_nested(&EXT4_I(second)->i_data_sem, I_DATA_SEM_OTHER); 55 } else { 56 down_write(&EXT4_I(second)->i_data_sem); 57 down_write_nested(&EXT4_I(first)->i_data_sem, I_DATA_SEM_OTHER); 58 59 } 60 } 61 62 /** 63 * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem 64 * 65 * @orig_inode: original inode structure to be released its lock first 66 * @donor_inode: donor inode structure to be released its lock second 67 * Release write lock of i_data_sem of two inodes (orig and donor). 68 */ 69 void 70 ext4_double_up_write_data_sem(struct inode *orig_inode, 71 struct inode *donor_inode) 72 { 73 up_write(&EXT4_I(orig_inode)->i_data_sem); 74 up_write(&EXT4_I(donor_inode)->i_data_sem); 75 } 76 77 /** 78 * mext_check_coverage - Check that all extents in range has the same type 79 * 80 * @inode: inode in question 81 * @from: block offset of inode 82 * @count: block count to be checked 83 * @unwritten: extents expected to be unwritten 84 * @err: pointer to save error value 85 * 86 * Return 1 if all extents in range has expected type, and zero otherwise. 87 */ 88 static int 89 mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count, 90 int unwritten, int *err) 91 { 92 struct ext4_ext_path *path = NULL; 93 struct ext4_extent *ext; 94 int ret = 0; 95 ext4_lblk_t last = from + count; 96 while (from < last) { 97 *err = get_ext_path(inode, from, &path); 98 if (*err) 99 goto out; 100 ext = path[ext_depth(inode)].p_ext; 101 if (unwritten != ext4_ext_is_unwritten(ext)) 102 goto out; 103 from += ext4_ext_get_actual_len(ext); 104 } 105 ret = 1; 106 out: 107 ext4_free_ext_path(path); 108 return ret; 109 } 110 111 /** 112 * mext_folio_double_lock - Grab and lock folio on both @inode1 and @inode2 113 * 114 * @inode1: the inode structure 115 * @inode2: the inode structure 116 * @index1: folio index 117 * @index2: folio index 118 * @folio: result folio vector 119 * 120 * Grab two locked folio for inode's by inode order 121 */ 122 static int 123 mext_folio_double_lock(struct inode *inode1, struct inode *inode2, 124 pgoff_t index1, pgoff_t index2, struct folio *folio[2]) 125 { 126 struct address_space *mapping[2]; 127 unsigned int flags; 128 129 BUG_ON(!inode1 || !inode2); 130 if (inode1 < inode2) { 131 mapping[0] = inode1->i_mapping; 132 mapping[1] = inode2->i_mapping; 133 } else { 134 swap(index1, index2); 135 mapping[0] = inode2->i_mapping; 136 mapping[1] = inode1->i_mapping; 137 } 138 139 flags = memalloc_nofs_save(); 140 folio[0] = __filemap_get_folio(mapping[0], index1, FGP_WRITEBEGIN, 141 mapping_gfp_mask(mapping[0])); 142 if (IS_ERR(folio[0])) { 143 memalloc_nofs_restore(flags); 144 return PTR_ERR(folio[0]); 145 } 146 147 folio[1] = __filemap_get_folio(mapping[1], index2, FGP_WRITEBEGIN, 148 mapping_gfp_mask(mapping[1])); 149 memalloc_nofs_restore(flags); 150 if (IS_ERR(folio[1])) { 151 folio_unlock(folio[0]); 152 folio_put(folio[0]); 153 return PTR_ERR(folio[1]); 154 } 155 /* 156 * __filemap_get_folio() may not wait on folio's writeback if 157 * BDI not demand that. But it is reasonable to be very conservative 158 * here and explicitly wait on folio's writeback 159 */ 160 folio_wait_writeback(folio[0]); 161 folio_wait_writeback(folio[1]); 162 if (inode1 > inode2) 163 swap(folio[0], folio[1]); 164 165 return 0; 166 } 167 168 /* Force folio buffers uptodate w/o dropping folio's lock */ 169 static int mext_page_mkuptodate(struct folio *folio, size_t from, size_t to) 170 { 171 struct inode *inode = folio->mapping->host; 172 sector_t block; 173 struct buffer_head *bh, *head; 174 unsigned int blocksize, block_start, block_end; 175 int nr = 0; 176 bool partial = false; 177 178 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 create_empty_buffers(&folio->page, blocksize, 0); 188 head = folio_buffers(folio); 189 } 190 191 block = (sector_t)folio->index << (PAGE_SHIFT - inode->i_blkbits); 192 for (bh = head, block_start = 0; bh != head || !block_start; 193 block++, block_start = block_end, bh = bh->b_this_page) { 194 block_end = block_start + blocksize; 195 if (block_end <= from || block_start >= to) { 196 if (!buffer_uptodate(bh)) 197 partial = true; 198 continue; 199 } 200 if (buffer_uptodate(bh)) 201 continue; 202 if (!buffer_mapped(bh)) { 203 int err = ext4_get_block(inode, block, bh, 0); 204 if (err) 205 return err; 206 if (!buffer_mapped(bh)) { 207 folio_zero_range(folio, block_start, blocksize); 208 set_buffer_uptodate(bh); 209 continue; 210 } 211 } 212 lock_buffer(bh); 213 if (buffer_uptodate(bh)) { 214 unlock_buffer(bh); 215 continue; 216 } 217 ext4_read_bh_nowait(bh, 0, NULL, false); 218 nr++; 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 if (!folio_buffers(folio[0])) 390 create_empty_buffers(&folio[0]->page, 1 << orig_inode->i_blkbits, 0); 391 bh = folio_buffers(folio[0]); 392 for (i = 0; i < data_offset_in_page; i++) 393 bh = bh->b_this_page; 394 for (i = 0; i < block_len_in_page; i++) { 395 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); 396 if (*err < 0) 397 goto repair_branches; 398 bh = bh->b_this_page; 399 } 400 401 block_commit_write(&folio[0]->page, from, from + replaced_size); 402 403 /* Even in case of data=writeback it is reasonable to pin 404 * inode to transaction, to prevent unexpected data loss */ 405 *err = ext4_jbd2_inode_add_write(handle, orig_inode, 406 (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size); 407 408 unlock_folios: 409 folio_unlock(folio[0]); 410 folio_put(folio[0]); 411 folio_unlock(folio[1]); 412 folio_put(folio[1]); 413 stop_journal: 414 ext4_journal_stop(handle); 415 if (*err == -ENOSPC && 416 ext4_should_retry_alloc(sb, &retries)) 417 goto again; 418 /* Buffer was busy because probably is pinned to journal transaction, 419 * force transaction commit may help to free it. */ 420 if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal && 421 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal)) 422 goto again; 423 return replaced_count; 424 425 repair_branches: 426 /* 427 * This should never ever happen! 428 * Extents are swapped already, but we are not able to copy data. 429 * Try to swap extents to it's original places 430 */ 431 ext4_double_down_write_data_sem(orig_inode, donor_inode); 432 replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode, 433 orig_blk_offset, donor_blk_offset, 434 block_len_in_page, 0, &err2); 435 ext4_double_up_write_data_sem(orig_inode, donor_inode); 436 if (replaced_count != block_len_in_page) { 437 ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset), 438 EIO, "Unable to copy data block," 439 " data will be lost."); 440 *err = -EIO; 441 } 442 replaced_count = 0; 443 goto unlock_folios; 444 } 445 446 /** 447 * mext_check_arguments - Check whether move extent can be done 448 * 449 * @orig_inode: original inode 450 * @donor_inode: donor inode 451 * @orig_start: logical start offset in block for orig 452 * @donor_start: logical start offset in block for donor 453 * @len: the number of blocks to be moved 454 * 455 * Check the arguments of ext4_move_extents() whether the files can be 456 * exchanged with each other. 457 * Return 0 on success, or a negative error value on failure. 458 */ 459 static int 460 mext_check_arguments(struct inode *orig_inode, 461 struct inode *donor_inode, __u64 orig_start, 462 __u64 donor_start, __u64 *len) 463 { 464 __u64 orig_eof, donor_eof; 465 unsigned int blkbits = orig_inode->i_blkbits; 466 unsigned int blocksize = 1 << blkbits; 467 468 orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits; 469 donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits; 470 471 472 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { 473 ext4_debug("ext4 move extent: suid or sgid is set" 474 " to donor file [ino:orig %lu, donor %lu]\n", 475 orig_inode->i_ino, donor_inode->i_ino); 476 return -EINVAL; 477 } 478 479 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) 480 return -EPERM; 481 482 /* Ext4 move extent does not support swap files */ 483 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { 484 ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n", 485 orig_inode->i_ino, donor_inode->i_ino); 486 return -ETXTBSY; 487 } 488 489 if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) { 490 ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n", 491 orig_inode->i_ino, donor_inode->i_ino); 492 return -EOPNOTSUPP; 493 } 494 495 /* Ext4 move extent supports only extent based file */ 496 if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) { 497 ext4_debug("ext4 move extent: orig file is not extents " 498 "based file [ino:orig %lu]\n", orig_inode->i_ino); 499 return -EOPNOTSUPP; 500 } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) { 501 ext4_debug("ext4 move extent: donor file is not extents " 502 "based file [ino:donor %lu]\n", donor_inode->i_ino); 503 return -EOPNOTSUPP; 504 } 505 506 if ((!orig_inode->i_size) || (!donor_inode->i_size)) { 507 ext4_debug("ext4 move extent: File size is 0 byte\n"); 508 return -EINVAL; 509 } 510 511 /* Start offset should be same */ 512 if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) != 513 (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) { 514 ext4_debug("ext4 move extent: orig and donor's start " 515 "offsets are not aligned [ino:orig %lu, donor %lu]\n", 516 orig_inode->i_ino, donor_inode->i_ino); 517 return -EINVAL; 518 } 519 520 if ((orig_start >= EXT_MAX_BLOCKS) || 521 (donor_start >= EXT_MAX_BLOCKS) || 522 (*len > EXT_MAX_BLOCKS) || 523 (donor_start + *len >= EXT_MAX_BLOCKS) || 524 (orig_start + *len >= EXT_MAX_BLOCKS)) { 525 ext4_debug("ext4 move extent: Can't handle over [%u] blocks " 526 "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS, 527 orig_inode->i_ino, donor_inode->i_ino); 528 return -EINVAL; 529 } 530 if (orig_eof <= orig_start) 531 *len = 0; 532 else if (orig_eof < orig_start + *len - 1) 533 *len = orig_eof - orig_start; 534 if (donor_eof <= donor_start) 535 *len = 0; 536 else if (donor_eof < donor_start + *len - 1) 537 *len = donor_eof - donor_start; 538 if (!*len) { 539 ext4_debug("ext4 move extent: len should not be 0 " 540 "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino, 541 donor_inode->i_ino); 542 return -EINVAL; 543 } 544 545 return 0; 546 } 547 548 /** 549 * ext4_move_extents - Exchange the specified range of a file 550 * 551 * @o_filp: file structure of the original file 552 * @d_filp: file structure of the donor file 553 * @orig_blk: start offset in block for orig 554 * @donor_blk: start offset in block for donor 555 * @len: the number of blocks to be moved 556 * @moved_len: moved block length 557 * 558 * This function returns 0 and moved block length is set in moved_len 559 * if succeed, otherwise returns error value. 560 * 561 */ 562 int 563 ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk, 564 __u64 donor_blk, __u64 len, __u64 *moved_len) 565 { 566 struct inode *orig_inode = file_inode(o_filp); 567 struct inode *donor_inode = file_inode(d_filp); 568 struct ext4_ext_path *path = NULL; 569 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 570 ext4_lblk_t o_end, o_start = orig_blk; 571 ext4_lblk_t d_start = donor_blk; 572 int ret; 573 574 if (orig_inode->i_sb != donor_inode->i_sb) { 575 ext4_debug("ext4 move extent: The argument files " 576 "should be in same FS [ino:orig %lu, donor %lu]\n", 577 orig_inode->i_ino, donor_inode->i_ino); 578 return -EINVAL; 579 } 580 581 /* orig and donor should be different inodes */ 582 if (orig_inode == donor_inode) { 583 ext4_debug("ext4 move extent: The argument files should not " 584 "be same inode [ino:orig %lu, donor %lu]\n", 585 orig_inode->i_ino, donor_inode->i_ino); 586 return -EINVAL; 587 } 588 589 /* Regular file check */ 590 if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) { 591 ext4_debug("ext4 move extent: The argument files should be " 592 "regular file [ino:orig %lu, donor %lu]\n", 593 orig_inode->i_ino, donor_inode->i_ino); 594 return -EINVAL; 595 } 596 597 /* TODO: it's not obvious how to swap blocks for inodes with full 598 journaling enabled */ 599 if (ext4_should_journal_data(orig_inode) || 600 ext4_should_journal_data(donor_inode)) { 601 ext4_msg(orig_inode->i_sb, KERN_ERR, 602 "Online defrag not supported with data journaling"); 603 return -EOPNOTSUPP; 604 } 605 606 if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) { 607 ext4_msg(orig_inode->i_sb, KERN_ERR, 608 "Online defrag not supported for encrypted files"); 609 return -EOPNOTSUPP; 610 } 611 612 /* Protect orig and donor inodes against a truncate */ 613 lock_two_nondirectories(orig_inode, donor_inode); 614 615 /* Wait for all existing dio workers */ 616 inode_dio_wait(orig_inode); 617 inode_dio_wait(donor_inode); 618 619 /* Protect extent tree against block allocations via delalloc */ 620 ext4_double_down_write_data_sem(orig_inode, donor_inode); 621 /* Check the filesystem environment whether move_extent can be done */ 622 ret = mext_check_arguments(orig_inode, donor_inode, orig_blk, 623 donor_blk, &len); 624 if (ret) 625 goto out; 626 o_end = o_start + len; 627 628 *moved_len = 0; 629 while (o_start < o_end) { 630 struct ext4_extent *ex; 631 ext4_lblk_t cur_blk, next_blk; 632 pgoff_t orig_page_index, donor_page_index; 633 int offset_in_page; 634 int unwritten, cur_len; 635 636 ret = get_ext_path(orig_inode, o_start, &path); 637 if (ret) 638 goto out; 639 ex = path[path->p_depth].p_ext; 640 cur_blk = le32_to_cpu(ex->ee_block); 641 cur_len = ext4_ext_get_actual_len(ex); 642 /* Check hole before the start pos */ 643 if (cur_blk + cur_len - 1 < o_start) { 644 next_blk = ext4_ext_next_allocated_block(path); 645 if (next_blk == EXT_MAX_BLOCKS) { 646 ret = -ENODATA; 647 goto out; 648 } 649 d_start += next_blk - o_start; 650 o_start = next_blk; 651 continue; 652 /* Check hole after the start pos */ 653 } else if (cur_blk > o_start) { 654 /* Skip hole */ 655 d_start += cur_blk - o_start; 656 o_start = cur_blk; 657 /* Extent inside requested range ?*/ 658 if (cur_blk >= o_end) 659 goto out; 660 } else { /* in_range(o_start, o_blk, o_len) */ 661 cur_len += cur_blk - o_start; 662 } 663 unwritten = ext4_ext_is_unwritten(ex); 664 if (o_end - o_start < cur_len) 665 cur_len = o_end - o_start; 666 667 orig_page_index = o_start >> (PAGE_SHIFT - 668 orig_inode->i_blkbits); 669 donor_page_index = d_start >> (PAGE_SHIFT - 670 donor_inode->i_blkbits); 671 offset_in_page = o_start % blocks_per_page; 672 if (cur_len > blocks_per_page - offset_in_page) 673 cur_len = blocks_per_page - offset_in_page; 674 /* 675 * Up semaphore to avoid following problems: 676 * a. transaction deadlock among ext4_journal_start, 677 * ->write_begin via pagefault, and jbd2_journal_commit 678 * b. racing with ->read_folio, ->write_begin, and 679 * ext4_get_block in move_extent_per_page 680 */ 681 ext4_double_up_write_data_sem(orig_inode, donor_inode); 682 /* Swap original branches with new branches */ 683 *moved_len += move_extent_per_page(o_filp, donor_inode, 684 orig_page_index, donor_page_index, 685 offset_in_page, cur_len, 686 unwritten, &ret); 687 ext4_double_down_write_data_sem(orig_inode, donor_inode); 688 if (ret < 0) 689 break; 690 o_start += cur_len; 691 d_start += cur_len; 692 } 693 694 out: 695 if (*moved_len) { 696 ext4_discard_preallocations(orig_inode, 0); 697 ext4_discard_preallocations(donor_inode, 0); 698 } 699 700 ext4_free_ext_path(path); 701 ext4_double_up_write_data_sem(orig_inode, donor_inode); 702 unlock_two_nondirectories(orig_inode, donor_inode); 703 704 return ret; 705 } 706