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 unsigned fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE; 130 131 BUG_ON(!inode1 || !inode2); 132 if (inode1 < inode2) { 133 mapping[0] = inode1->i_mapping; 134 mapping[1] = inode2->i_mapping; 135 } else { 136 swap(index1, index2); 137 mapping[0] = inode2->i_mapping; 138 mapping[1] = inode1->i_mapping; 139 } 140 141 flags = memalloc_nofs_save(); 142 folio[0] = __filemap_get_folio(mapping[0], index1, fgp_flags, 143 mapping_gfp_mask(mapping[0])); 144 if (!folio[0]) { 145 memalloc_nofs_restore(flags); 146 return -ENOMEM; 147 } 148 149 folio[1] = __filemap_get_folio(mapping[1], index2, fgp_flags, 150 mapping_gfp_mask(mapping[1])); 151 memalloc_nofs_restore(flags); 152 if (!folio[1]) { 153 folio_unlock(folio[0]); 154 folio_put(folio[0]); 155 return -ENOMEM; 156 } 157 /* 158 * __filemap_get_folio() may not wait on folio's writeback if 159 * BDI not demand that. But it is reasonable to be very conservative 160 * here and explicitly wait on folio's writeback 161 */ 162 folio_wait_writeback(folio[0]); 163 folio_wait_writeback(folio[1]); 164 if (inode1 > inode2) 165 swap(folio[0], folio[1]); 166 167 return 0; 168 } 169 170 /* Force page buffers uptodate w/o dropping page's lock */ 171 static int 172 mext_page_mkuptodate(struct page *page, unsigned from, unsigned to) 173 { 174 struct inode *inode = page->mapping->host; 175 sector_t block; 176 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; 177 unsigned int blocksize, block_start, block_end; 178 int i, err, nr = 0, partial = 0; 179 BUG_ON(!PageLocked(page)); 180 BUG_ON(PageWriteback(page)); 181 182 if (PageUptodate(page)) 183 return 0; 184 185 blocksize = i_blocksize(inode); 186 if (!page_has_buffers(page)) 187 create_empty_buffers(page, blocksize, 0); 188 189 head = page_buffers(page); 190 block = (sector_t)page->index << (PAGE_SHIFT - inode->i_blkbits); 191 for (bh = head, block_start = 0; bh != head || !block_start; 192 block++, block_start = block_end, bh = bh->b_this_page) { 193 block_end = block_start + blocksize; 194 if (block_end <= from || block_start >= to) { 195 if (!buffer_uptodate(bh)) 196 partial = 1; 197 continue; 198 } 199 if (buffer_uptodate(bh)) 200 continue; 201 if (!buffer_mapped(bh)) { 202 err = ext4_get_block(inode, block, bh, 0); 203 if (err) { 204 SetPageError(page); 205 return err; 206 } 207 if (!buffer_mapped(bh)) { 208 zero_user(page, block_start, blocksize); 209 set_buffer_uptodate(bh); 210 continue; 211 } 212 } 213 BUG_ON(nr >= MAX_BUF_PER_PAGE); 214 arr[nr++] = bh; 215 } 216 /* No io required */ 217 if (!nr) 218 goto out; 219 220 for (i = 0; i < nr; i++) { 221 bh = arr[i]; 222 if (!bh_uptodate_or_lock(bh)) { 223 err = ext4_read_bh(bh, 0, NULL); 224 if (err) 225 return err; 226 } 227 } 228 out: 229 if (!partial) 230 SetPageUptodate(page); 231 return 0; 232 } 233 234 /** 235 * move_extent_per_page - Move extent data per page 236 * 237 * @o_filp: file structure of original file 238 * @donor_inode: donor inode 239 * @orig_page_offset: page index on original file 240 * @donor_page_offset: page index on donor file 241 * @data_offset_in_page: block index where data swapping starts 242 * @block_len_in_page: the number of blocks to be swapped 243 * @unwritten: orig extent is unwritten or not 244 * @err: pointer to save return value 245 * 246 * Save the data in original inode blocks and replace original inode extents 247 * with donor inode extents by calling ext4_swap_extents(). 248 * Finally, write out the saved data in new original inode blocks. Return 249 * replaced block count. 250 */ 251 static int 252 move_extent_per_page(struct file *o_filp, struct inode *donor_inode, 253 pgoff_t orig_page_offset, pgoff_t donor_page_offset, 254 int data_offset_in_page, 255 int block_len_in_page, int unwritten, int *err) 256 { 257 struct inode *orig_inode = file_inode(o_filp); 258 struct folio *folio[2] = {NULL, NULL}; 259 handle_t *handle; 260 ext4_lblk_t orig_blk_offset, donor_blk_offset; 261 unsigned long blocksize = orig_inode->i_sb->s_blocksize; 262 unsigned int tmp_data_size, data_size, replaced_size; 263 int i, err2, jblocks, retries = 0; 264 int replaced_count = 0; 265 int from = data_offset_in_page << orig_inode->i_blkbits; 266 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 267 struct super_block *sb = orig_inode->i_sb; 268 struct buffer_head *bh = NULL; 269 270 /* 271 * It needs twice the amount of ordinary journal buffers because 272 * inode and donor_inode may change each different metadata blocks. 273 */ 274 again: 275 *err = 0; 276 jblocks = ext4_writepage_trans_blocks(orig_inode) * 2; 277 handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks); 278 if (IS_ERR(handle)) { 279 *err = PTR_ERR(handle); 280 return 0; 281 } 282 283 orig_blk_offset = orig_page_offset * blocks_per_page + 284 data_offset_in_page; 285 286 donor_blk_offset = donor_page_offset * blocks_per_page + 287 data_offset_in_page; 288 289 /* Calculate data_size */ 290 if ((orig_blk_offset + block_len_in_page - 1) == 291 ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) { 292 /* Replace the last block */ 293 tmp_data_size = orig_inode->i_size & (blocksize - 1); 294 /* 295 * If data_size equal zero, it shows data_size is multiples of 296 * blocksize. So we set appropriate value. 297 */ 298 if (tmp_data_size == 0) 299 tmp_data_size = blocksize; 300 301 data_size = tmp_data_size + 302 ((block_len_in_page - 1) << orig_inode->i_blkbits); 303 } else 304 data_size = block_len_in_page << orig_inode->i_blkbits; 305 306 replaced_size = data_size; 307 308 *err = mext_folio_double_lock(orig_inode, donor_inode, orig_page_offset, 309 donor_page_offset, folio); 310 if (unlikely(*err < 0)) 311 goto stop_journal; 312 /* 313 * If orig extent was unwritten it can become initialized 314 * at any time after i_data_sem was dropped, in order to 315 * serialize with delalloc we have recheck extent while we 316 * hold page's lock, if it is still the case data copy is not 317 * necessary, just swap data blocks between orig and donor. 318 */ 319 320 VM_BUG_ON_FOLIO(folio_test_large(folio[0]), folio[0]); 321 VM_BUG_ON_FOLIO(folio_test_large(folio[1]), folio[1]); 322 VM_BUG_ON_FOLIO(folio_nr_pages(folio[0]) != folio_nr_pages(folio[1]), folio[1]); 323 324 if (unwritten) { 325 ext4_double_down_write_data_sem(orig_inode, donor_inode); 326 /* If any of extents in range became initialized we have to 327 * fallback to data copying */ 328 unwritten = mext_check_coverage(orig_inode, orig_blk_offset, 329 block_len_in_page, 1, err); 330 if (*err) 331 goto drop_data_sem; 332 333 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset, 334 block_len_in_page, 1, err); 335 if (*err) 336 goto drop_data_sem; 337 338 if (!unwritten) { 339 ext4_double_up_write_data_sem(orig_inode, donor_inode); 340 goto data_copy; 341 } 342 if ((folio_has_private(folio[0]) && 343 !filemap_release_folio(folio[0], 0)) || 344 (folio_has_private(folio[1]) && 345 !filemap_release_folio(folio[1], 0))) { 346 *err = -EBUSY; 347 goto drop_data_sem; 348 } 349 replaced_count = ext4_swap_extents(handle, orig_inode, 350 donor_inode, orig_blk_offset, 351 donor_blk_offset, 352 block_len_in_page, 1, err); 353 drop_data_sem: 354 ext4_double_up_write_data_sem(orig_inode, donor_inode); 355 goto unlock_folios; 356 } 357 data_copy: 358 *err = mext_page_mkuptodate(&folio[0]->page, from, from + replaced_size); 359 if (*err) 360 goto unlock_folios; 361 362 /* At this point all buffers in range are uptodate, old mapping layout 363 * is no longer required, try to drop it now. */ 364 if ((folio_has_private(folio[0]) && 365 !filemap_release_folio(folio[0], 0)) || 366 (folio_has_private(folio[1]) && 367 !filemap_release_folio(folio[1], 0))) { 368 *err = -EBUSY; 369 goto unlock_folios; 370 } 371 ext4_double_down_write_data_sem(orig_inode, donor_inode); 372 replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, 373 orig_blk_offset, donor_blk_offset, 374 block_len_in_page, 1, err); 375 ext4_double_up_write_data_sem(orig_inode, donor_inode); 376 if (*err) { 377 if (replaced_count) { 378 block_len_in_page = replaced_count; 379 replaced_size = 380 block_len_in_page << orig_inode->i_blkbits; 381 } else 382 goto unlock_folios; 383 } 384 /* Perform all necessary steps similar write_begin()/write_end() 385 * but keeping in mind that i_size will not change */ 386 if (!folio_buffers(folio[0])) 387 create_empty_buffers(&folio[0]->page, 1 << orig_inode->i_blkbits, 0); 388 bh = folio_buffers(folio[0]); 389 for (i = 0; i < data_offset_in_page; i++) 390 bh = bh->b_this_page; 391 for (i = 0; i < block_len_in_page; i++) { 392 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); 393 if (*err < 0) 394 break; 395 bh = bh->b_this_page; 396 } 397 if (!*err) 398 *err = block_commit_write(&folio[0]->page, from, from + replaced_size); 399 400 if (unlikely(*err < 0)) 401 goto repair_branches; 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 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 ret = get_ext_path(orig_inode, o_start, &path); 636 if (ret) 637 goto out; 638 ex = path[path->p_depth].p_ext; 639 cur_blk = le32_to_cpu(ex->ee_block); 640 cur_len = ext4_ext_get_actual_len(ex); 641 /* Check hole before the start pos */ 642 if (cur_blk + cur_len - 1 < o_start) { 643 next_blk = ext4_ext_next_allocated_block(path); 644 if (next_blk == EXT_MAX_BLOCKS) { 645 ret = -ENODATA; 646 goto out; 647 } 648 d_start += next_blk - o_start; 649 o_start = next_blk; 650 continue; 651 /* Check hole after the start pos */ 652 } else if (cur_blk > o_start) { 653 /* Skip hole */ 654 d_start += cur_blk - o_start; 655 o_start = cur_blk; 656 /* Extent inside requested range ?*/ 657 if (cur_blk >= o_end) 658 goto out; 659 } else { /* in_range(o_start, o_blk, o_len) */ 660 cur_len += cur_blk - o_start; 661 } 662 unwritten = ext4_ext_is_unwritten(ex); 663 if (o_end - o_start < cur_len) 664 cur_len = o_end - o_start; 665 666 orig_page_index = o_start >> (PAGE_SHIFT - 667 orig_inode->i_blkbits); 668 donor_page_index = d_start >> (PAGE_SHIFT - 669 donor_inode->i_blkbits); 670 offset_in_page = o_start % blocks_per_page; 671 if (cur_len > blocks_per_page - offset_in_page) 672 cur_len = blocks_per_page - offset_in_page; 673 /* 674 * Up semaphore to avoid following problems: 675 * a. transaction deadlock among ext4_journal_start, 676 * ->write_begin via pagefault, and jbd2_journal_commit 677 * b. racing with ->read_folio, ->write_begin, and 678 * ext4_get_block in move_extent_per_page 679 */ 680 ext4_double_up_write_data_sem(orig_inode, donor_inode); 681 /* Swap original branches with new branches */ 682 move_extent_per_page(o_filp, donor_inode, 683 orig_page_index, donor_page_index, 684 offset_in_page, cur_len, 685 unwritten, &ret); 686 ext4_double_down_write_data_sem(orig_inode, donor_inode); 687 if (ret < 0) 688 break; 689 o_start += cur_len; 690 d_start += cur_len; 691 } 692 *moved_len = o_start - orig_blk; 693 if (*moved_len > len) 694 *moved_len = len; 695 696 out: 697 if (*moved_len) { 698 ext4_discard_preallocations(orig_inode, 0); 699 ext4_discard_preallocations(donor_inode, 0); 700 } 701 702 ext4_free_ext_path(path); 703 ext4_double_up_write_data_sem(orig_inode, donor_inode); 704 unlock_two_nondirectories(orig_inode, donor_inode); 705 706 return ret; 707 } 708