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 folio_set_error(folio); 204 return err; 205 } 206 if (!buffer_mapped(bh)) { 207 folio_zero_range(folio, block_start, blocksize); 208 set_buffer_uptodate(bh); 209 continue; 210 } 211 } 212 BUG_ON(nr >= MAX_BUF_PER_PAGE); 213 arr[nr++] = bh; 214 } 215 /* No io required */ 216 if (!nr) 217 goto out; 218 219 for (i = 0; i < nr; i++) { 220 bh = arr[i]; 221 if (!bh_uptodate_or_lock(bh)) { 222 err = ext4_read_bh(bh, 0, NULL); 223 if (err) 224 return err; 225 } 226 } 227 out: 228 if (!partial) 229 folio_mark_uptodate(folio); 230 return 0; 231 } 232 233 /** 234 * move_extent_per_page - Move extent data per page 235 * 236 * @o_filp: file structure of original file 237 * @donor_inode: donor inode 238 * @orig_page_offset: page index on original file 239 * @donor_page_offset: page index on donor file 240 * @data_offset_in_page: block index where data swapping starts 241 * @block_len_in_page: the number of blocks to be swapped 242 * @unwritten: orig extent is unwritten or not 243 * @err: pointer to save return value 244 * 245 * Save the data in original inode blocks and replace original inode extents 246 * with donor inode extents by calling ext4_swap_extents(). 247 * Finally, write out the saved data in new original inode blocks. Return 248 * replaced block count. 249 */ 250 static int 251 move_extent_per_page(struct file *o_filp, struct inode *donor_inode, 252 pgoff_t orig_page_offset, pgoff_t donor_page_offset, 253 int data_offset_in_page, 254 int block_len_in_page, int unwritten, int *err) 255 { 256 struct inode *orig_inode = file_inode(o_filp); 257 struct folio *folio[2] = {NULL, NULL}; 258 handle_t *handle; 259 ext4_lblk_t orig_blk_offset, donor_blk_offset; 260 unsigned long blocksize = orig_inode->i_sb->s_blocksize; 261 unsigned int tmp_data_size, data_size, replaced_size; 262 int i, err2, jblocks, retries = 0; 263 int replaced_count = 0; 264 int from = data_offset_in_page << orig_inode->i_blkbits; 265 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 266 struct super_block *sb = orig_inode->i_sb; 267 struct buffer_head *bh = NULL; 268 269 /* 270 * It needs twice the amount of ordinary journal buffers because 271 * inode and donor_inode may change each different metadata blocks. 272 */ 273 again: 274 *err = 0; 275 jblocks = ext4_writepage_trans_blocks(orig_inode) * 2; 276 handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks); 277 if (IS_ERR(handle)) { 278 *err = PTR_ERR(handle); 279 return 0; 280 } 281 282 orig_blk_offset = orig_page_offset * blocks_per_page + 283 data_offset_in_page; 284 285 donor_blk_offset = donor_page_offset * blocks_per_page + 286 data_offset_in_page; 287 288 /* Calculate data_size */ 289 if ((orig_blk_offset + block_len_in_page - 1) == 290 ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) { 291 /* Replace the last block */ 292 tmp_data_size = orig_inode->i_size & (blocksize - 1); 293 /* 294 * If data_size equal zero, it shows data_size is multiples of 295 * blocksize. So we set appropriate value. 296 */ 297 if (tmp_data_size == 0) 298 tmp_data_size = blocksize; 299 300 data_size = tmp_data_size + 301 ((block_len_in_page - 1) << orig_inode->i_blkbits); 302 } else 303 data_size = block_len_in_page << orig_inode->i_blkbits; 304 305 replaced_size = data_size; 306 307 *err = mext_folio_double_lock(orig_inode, donor_inode, orig_page_offset, 308 donor_page_offset, folio); 309 if (unlikely(*err < 0)) 310 goto stop_journal; 311 /* 312 * If orig extent was unwritten it can become initialized 313 * at any time after i_data_sem was dropped, in order to 314 * serialize with delalloc we have recheck extent while we 315 * hold page's lock, if it is still the case data copy is not 316 * necessary, just swap data blocks between orig and donor. 317 */ 318 319 VM_BUG_ON_FOLIO(folio_test_large(folio[0]), folio[0]); 320 VM_BUG_ON_FOLIO(folio_test_large(folio[1]), folio[1]); 321 VM_BUG_ON_FOLIO(folio_nr_pages(folio[0]) != folio_nr_pages(folio[1]), folio[1]); 322 323 if (unwritten) { 324 ext4_double_down_write_data_sem(orig_inode, donor_inode); 325 /* If any of extents in range became initialized we have to 326 * fallback to data copying */ 327 unwritten = mext_check_coverage(orig_inode, orig_blk_offset, 328 block_len_in_page, 1, err); 329 if (*err) 330 goto drop_data_sem; 331 332 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset, 333 block_len_in_page, 1, err); 334 if (*err) 335 goto drop_data_sem; 336 337 if (!unwritten) { 338 ext4_double_up_write_data_sem(orig_inode, donor_inode); 339 goto data_copy; 340 } 341 if (!filemap_release_folio(folio[0], 0) || 342 !filemap_release_folio(folio[1], 0)) { 343 *err = -EBUSY; 344 goto drop_data_sem; 345 } 346 replaced_count = ext4_swap_extents(handle, orig_inode, 347 donor_inode, orig_blk_offset, 348 donor_blk_offset, 349 block_len_in_page, 1, err); 350 drop_data_sem: 351 ext4_double_up_write_data_sem(orig_inode, donor_inode); 352 goto unlock_folios; 353 } 354 data_copy: 355 *err = mext_page_mkuptodate(folio[0], from, from + replaced_size); 356 if (*err) 357 goto unlock_folios; 358 359 /* At this point all buffers in range are uptodate, old mapping layout 360 * is no longer required, try to drop it now. */ 361 if (!filemap_release_folio(folio[0], 0) || 362 !filemap_release_folio(folio[1], 0)) { 363 *err = -EBUSY; 364 goto unlock_folios; 365 } 366 ext4_double_down_write_data_sem(orig_inode, donor_inode); 367 replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, 368 orig_blk_offset, donor_blk_offset, 369 block_len_in_page, 1, err); 370 ext4_double_up_write_data_sem(orig_inode, donor_inode); 371 if (*err) { 372 if (replaced_count) { 373 block_len_in_page = replaced_count; 374 replaced_size = 375 block_len_in_page << orig_inode->i_blkbits; 376 } else 377 goto unlock_folios; 378 } 379 /* Perform all necessary steps similar write_begin()/write_end() 380 * but keeping in mind that i_size will not change */ 381 bh = folio_buffers(folio[0]); 382 if (!bh) 383 bh = create_empty_buffers(folio[0], 384 1 << orig_inode->i_blkbits, 0); 385 for (i = 0; i < data_offset_in_page; i++) 386 bh = bh->b_this_page; 387 for (i = 0; i < block_len_in_page; i++) { 388 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); 389 if (*err < 0) 390 goto repair_branches; 391 bh = bh->b_this_page; 392 } 393 394 block_commit_write(&folio[0]->page, from, from + replaced_size); 395 396 /* Even in case of data=writeback it is reasonable to pin 397 * inode to transaction, to prevent unexpected data loss */ 398 *err = ext4_jbd2_inode_add_write(handle, orig_inode, 399 (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size); 400 401 unlock_folios: 402 folio_unlock(folio[0]); 403 folio_put(folio[0]); 404 folio_unlock(folio[1]); 405 folio_put(folio[1]); 406 stop_journal: 407 ext4_journal_stop(handle); 408 if (*err == -ENOSPC && 409 ext4_should_retry_alloc(sb, &retries)) 410 goto again; 411 /* Buffer was busy because probably is pinned to journal transaction, 412 * force transaction commit may help to free it. */ 413 if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal && 414 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal)) 415 goto again; 416 return replaced_count; 417 418 repair_branches: 419 /* 420 * This should never ever happen! 421 * Extents are swapped already, but we are not able to copy data. 422 * Try to swap extents to it's original places 423 */ 424 ext4_double_down_write_data_sem(orig_inode, donor_inode); 425 replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode, 426 orig_blk_offset, donor_blk_offset, 427 block_len_in_page, 0, &err2); 428 ext4_double_up_write_data_sem(orig_inode, donor_inode); 429 if (replaced_count != block_len_in_page) { 430 ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset), 431 EIO, "Unable to copy data block," 432 " data will be lost."); 433 *err = -EIO; 434 } 435 replaced_count = 0; 436 goto unlock_folios; 437 } 438 439 /** 440 * mext_check_arguments - Check whether move extent can be done 441 * 442 * @orig_inode: original inode 443 * @donor_inode: donor inode 444 * @orig_start: logical start offset in block for orig 445 * @donor_start: logical start offset in block for donor 446 * @len: the number of blocks to be moved 447 * 448 * Check the arguments of ext4_move_extents() whether the files can be 449 * exchanged with each other. 450 * Return 0 on success, or a negative error value on failure. 451 */ 452 static int 453 mext_check_arguments(struct inode *orig_inode, 454 struct inode *donor_inode, __u64 orig_start, 455 __u64 donor_start, __u64 *len) 456 { 457 __u64 orig_eof, donor_eof; 458 unsigned int blkbits = orig_inode->i_blkbits; 459 unsigned int blocksize = 1 << blkbits; 460 461 orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits; 462 donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits; 463 464 465 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { 466 ext4_debug("ext4 move extent: suid or sgid is set" 467 " to donor file [ino:orig %lu, donor %lu]\n", 468 orig_inode->i_ino, donor_inode->i_ino); 469 return -EINVAL; 470 } 471 472 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) 473 return -EPERM; 474 475 /* Ext4 move extent does not support swap files */ 476 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { 477 ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n", 478 orig_inode->i_ino, donor_inode->i_ino); 479 return -ETXTBSY; 480 } 481 482 if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) { 483 ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n", 484 orig_inode->i_ino, donor_inode->i_ino); 485 return -EOPNOTSUPP; 486 } 487 488 /* Ext4 move extent supports only extent based file */ 489 if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) { 490 ext4_debug("ext4 move extent: orig file is not extents " 491 "based file [ino:orig %lu]\n", orig_inode->i_ino); 492 return -EOPNOTSUPP; 493 } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) { 494 ext4_debug("ext4 move extent: donor file is not extents " 495 "based file [ino:donor %lu]\n", donor_inode->i_ino); 496 return -EOPNOTSUPP; 497 } 498 499 if ((!orig_inode->i_size) || (!donor_inode->i_size)) { 500 ext4_debug("ext4 move extent: File size is 0 byte\n"); 501 return -EINVAL; 502 } 503 504 /* Start offset should be same */ 505 if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) != 506 (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) { 507 ext4_debug("ext4 move extent: orig and donor's start " 508 "offsets are not aligned [ino:orig %lu, donor %lu]\n", 509 orig_inode->i_ino, donor_inode->i_ino); 510 return -EINVAL; 511 } 512 513 if ((orig_start >= EXT_MAX_BLOCKS) || 514 (donor_start >= EXT_MAX_BLOCKS) || 515 (*len > EXT_MAX_BLOCKS) || 516 (donor_start + *len >= EXT_MAX_BLOCKS) || 517 (orig_start + *len >= EXT_MAX_BLOCKS)) { 518 ext4_debug("ext4 move extent: Can't handle over [%u] blocks " 519 "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS, 520 orig_inode->i_ino, donor_inode->i_ino); 521 return -EINVAL; 522 } 523 if (orig_eof <= orig_start) 524 *len = 0; 525 else if (orig_eof < orig_start + *len - 1) 526 *len = orig_eof - orig_start; 527 if (donor_eof <= donor_start) 528 *len = 0; 529 else if (donor_eof < donor_start + *len - 1) 530 *len = donor_eof - donor_start; 531 if (!*len) { 532 ext4_debug("ext4 move extent: len should not be 0 " 533 "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino, 534 donor_inode->i_ino); 535 return -EINVAL; 536 } 537 538 return 0; 539 } 540 541 /** 542 * ext4_move_extents - Exchange the specified range of a file 543 * 544 * @o_filp: file structure of the original file 545 * @d_filp: file structure of the donor file 546 * @orig_blk: start offset in block for orig 547 * @donor_blk: start offset in block for donor 548 * @len: the number of blocks to be moved 549 * @moved_len: moved block length 550 * 551 * This function returns 0 and moved block length is set in moved_len 552 * if succeed, otherwise returns error value. 553 * 554 */ 555 int 556 ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk, 557 __u64 donor_blk, __u64 len, __u64 *moved_len) 558 { 559 struct inode *orig_inode = file_inode(o_filp); 560 struct inode *donor_inode = file_inode(d_filp); 561 struct ext4_ext_path *path = NULL; 562 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 563 ext4_lblk_t o_end, o_start = orig_blk; 564 ext4_lblk_t d_start = donor_blk; 565 int ret; 566 567 if (orig_inode->i_sb != donor_inode->i_sb) { 568 ext4_debug("ext4 move extent: The argument files " 569 "should be in same FS [ino:orig %lu, donor %lu]\n", 570 orig_inode->i_ino, donor_inode->i_ino); 571 return -EINVAL; 572 } 573 574 /* orig and donor should be different inodes */ 575 if (orig_inode == donor_inode) { 576 ext4_debug("ext4 move extent: The argument files should not " 577 "be same inode [ino:orig %lu, donor %lu]\n", 578 orig_inode->i_ino, donor_inode->i_ino); 579 return -EINVAL; 580 } 581 582 /* Regular file check */ 583 if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) { 584 ext4_debug("ext4 move extent: The argument files should be " 585 "regular file [ino:orig %lu, donor %lu]\n", 586 orig_inode->i_ino, donor_inode->i_ino); 587 return -EINVAL; 588 } 589 590 /* TODO: it's not obvious how to swap blocks for inodes with full 591 journaling enabled */ 592 if (ext4_should_journal_data(orig_inode) || 593 ext4_should_journal_data(donor_inode)) { 594 ext4_msg(orig_inode->i_sb, KERN_ERR, 595 "Online defrag not supported with data journaling"); 596 return -EOPNOTSUPP; 597 } 598 599 if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) { 600 ext4_msg(orig_inode->i_sb, KERN_ERR, 601 "Online defrag not supported for encrypted files"); 602 return -EOPNOTSUPP; 603 } 604 605 /* Protect orig and donor inodes against a truncate */ 606 lock_two_nondirectories(orig_inode, donor_inode); 607 608 /* Wait for all existing dio workers */ 609 inode_dio_wait(orig_inode); 610 inode_dio_wait(donor_inode); 611 612 /* Protect extent tree against block allocations via delalloc */ 613 ext4_double_down_write_data_sem(orig_inode, donor_inode); 614 /* Check the filesystem environment whether move_extent can be done */ 615 ret = mext_check_arguments(orig_inode, donor_inode, orig_blk, 616 donor_blk, &len); 617 if (ret) 618 goto out; 619 o_end = o_start + len; 620 621 while (o_start < o_end) { 622 struct ext4_extent *ex; 623 ext4_lblk_t cur_blk, next_blk; 624 pgoff_t orig_page_index, donor_page_index; 625 int offset_in_page; 626 int unwritten, cur_len; 627 628 ret = get_ext_path(orig_inode, o_start, &path); 629 if (ret) 630 goto out; 631 ex = path[path->p_depth].p_ext; 632 cur_blk = le32_to_cpu(ex->ee_block); 633 cur_len = ext4_ext_get_actual_len(ex); 634 /* Check hole before the start pos */ 635 if (cur_blk + cur_len - 1 < o_start) { 636 next_blk = ext4_ext_next_allocated_block(path); 637 if (next_blk == EXT_MAX_BLOCKS) { 638 ret = -ENODATA; 639 goto out; 640 } 641 d_start += next_blk - o_start; 642 o_start = next_blk; 643 continue; 644 /* Check hole after the start pos */ 645 } else if (cur_blk > o_start) { 646 /* Skip hole */ 647 d_start += cur_blk - o_start; 648 o_start = cur_blk; 649 /* Extent inside requested range ?*/ 650 if (cur_blk >= o_end) 651 goto out; 652 } else { /* in_range(o_start, o_blk, o_len) */ 653 cur_len += cur_blk - o_start; 654 } 655 unwritten = ext4_ext_is_unwritten(ex); 656 if (o_end - o_start < cur_len) 657 cur_len = o_end - o_start; 658 659 orig_page_index = o_start >> (PAGE_SHIFT - 660 orig_inode->i_blkbits); 661 donor_page_index = d_start >> (PAGE_SHIFT - 662 donor_inode->i_blkbits); 663 offset_in_page = o_start % blocks_per_page; 664 if (cur_len > blocks_per_page - offset_in_page) 665 cur_len = blocks_per_page - offset_in_page; 666 /* 667 * Up semaphore to avoid following problems: 668 * a. transaction deadlock among ext4_journal_start, 669 * ->write_begin via pagefault, and jbd2_journal_commit 670 * b. racing with ->read_folio, ->write_begin, and 671 * ext4_get_block in move_extent_per_page 672 */ 673 ext4_double_up_write_data_sem(orig_inode, donor_inode); 674 /* Swap original branches with new branches */ 675 move_extent_per_page(o_filp, donor_inode, 676 orig_page_index, donor_page_index, 677 offset_in_page, cur_len, 678 unwritten, &ret); 679 ext4_double_down_write_data_sem(orig_inode, donor_inode); 680 if (ret < 0) 681 break; 682 o_start += cur_len; 683 d_start += cur_len; 684 } 685 *moved_len = o_start - orig_blk; 686 if (*moved_len > len) 687 *moved_len = len; 688 689 out: 690 if (*moved_len) { 691 ext4_discard_preallocations(orig_inode, 0); 692 ext4_discard_preallocations(donor_inode, 0); 693 } 694 695 ext4_free_ext_path(path); 696 ext4_double_up_write_data_sem(orig_inode, donor_inode); 697 unlock_two_nondirectories(orig_inode, donor_inode); 698 699 return ret; 700 } 701