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 */ 25static inline int 26get_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 */ 50void 51ext4_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 */ 70void 71ext4_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 */ 89static int 90mext_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; 107out: 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 */ 123static int 124mext_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 */ 170static int 171mext_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 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 = 1; 198 continue; 199 } 200 if (buffer_uptodate(bh)) 201 continue; 202 if (!buffer_mapped(bh)) { 203 err = ext4_get_block(inode, block, bh, 0); 204 if (err) { 205 folio_set_error(folio); 206 return err; 207 } 208 if (!buffer_mapped(bh)) { 209 folio_zero_range(folio, block_start, blocksize); 210 set_buffer_uptodate(bh); 211 continue; 212 } 213 } 214 BUG_ON(nr >= MAX_BUF_PER_PAGE); 215 arr[nr++] = bh; 216 } 217 /* No io required */ 218 if (!nr) 219 goto out; 220 221 for (i = 0; i < nr; i++) { 222 bh = arr[i]; 223 if (!bh_uptodate_or_lock(bh)) { 224 err = ext4_read_bh(bh, 0, NULL); 225 if (err) 226 return err; 227 } 228 } 229out: 230 if (!partial) 231 folio_mark_uptodate(folio); 232 return 0; 233} 234 235/** 236 * move_extent_per_page - Move extent data per page 237 * 238 * @o_filp: file structure of original file 239 * @donor_inode: donor inode 240 * @orig_page_offset: page index on original file 241 * @donor_page_offset: page index on donor file 242 * @data_offset_in_page: block index where data swapping starts 243 * @block_len_in_page: the number of blocks to be swapped 244 * @unwritten: orig extent is unwritten or not 245 * @err: pointer to save return value 246 * 247 * Save the data in original inode blocks and replace original inode extents 248 * with donor inode extents by calling ext4_swap_extents(). 249 * Finally, write out the saved data in new original inode blocks. Return 250 * replaced block count. 251 */ 252static int 253move_extent_per_page(struct file *o_filp, struct inode *donor_inode, 254 pgoff_t orig_page_offset, pgoff_t donor_page_offset, 255 int data_offset_in_page, 256 int block_len_in_page, int unwritten, int *err) 257{ 258 struct inode *orig_inode = file_inode(o_filp); 259 struct folio *folio[2] = {NULL, NULL}; 260 handle_t *handle; 261 ext4_lblk_t orig_blk_offset, donor_blk_offset; 262 unsigned long blocksize = orig_inode->i_sb->s_blocksize; 263 unsigned int tmp_data_size, data_size, replaced_size; 264 int i, err2, jblocks, retries = 0; 265 int replaced_count = 0; 266 int from = data_offset_in_page << orig_inode->i_blkbits; 267 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 268 struct super_block *sb = orig_inode->i_sb; 269 struct buffer_head *bh = NULL; 270 271 /* 272 * It needs twice the amount of ordinary journal buffers because 273 * inode and donor_inode may change each different metadata blocks. 274 */ 275again: 276 *err = 0; 277 jblocks = ext4_writepage_trans_blocks(orig_inode) * 2; 278 handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks); 279 if (IS_ERR(handle)) { 280 *err = PTR_ERR(handle); 281 return 0; 282 } 283 284 orig_blk_offset = orig_page_offset * blocks_per_page + 285 data_offset_in_page; 286 287 donor_blk_offset = donor_page_offset * blocks_per_page + 288 data_offset_in_page; 289 290 /* Calculate data_size */ 291 if ((orig_blk_offset + block_len_in_page - 1) == 292 ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) { 293 /* Replace the last block */ 294 tmp_data_size = orig_inode->i_size & (blocksize - 1); 295 /* 296 * If data_size equal zero, it shows data_size is multiples of 297 * blocksize. So we set appropriate value. 298 */ 299 if (tmp_data_size == 0) 300 tmp_data_size = blocksize; 301 302 data_size = tmp_data_size + 303 ((block_len_in_page - 1) << orig_inode->i_blkbits); 304 } else 305 data_size = block_len_in_page << orig_inode->i_blkbits; 306 307 replaced_size = data_size; 308 309 *err = mext_folio_double_lock(orig_inode, donor_inode, orig_page_offset, 310 donor_page_offset, folio); 311 if (unlikely(*err < 0)) 312 goto stop_journal; 313 /* 314 * If orig extent was unwritten it can become initialized 315 * at any time after i_data_sem was dropped, in order to 316 * serialize with delalloc we have recheck extent while we 317 * hold page's lock, if it is still the case data copy is not 318 * necessary, just swap data blocks between orig and donor. 319 */ 320 321 VM_BUG_ON_FOLIO(folio_test_large(folio[0]), folio[0]); 322 VM_BUG_ON_FOLIO(folio_test_large(folio[1]), folio[1]); 323 VM_BUG_ON_FOLIO(folio_nr_pages(folio[0]) != folio_nr_pages(folio[1]), folio[1]); 324 325 if (unwritten) { 326 ext4_double_down_write_data_sem(orig_inode, donor_inode); 327 /* If any of extents in range became initialized we have to 328 * fallback to data copying */ 329 unwritten = mext_check_coverage(orig_inode, orig_blk_offset, 330 block_len_in_page, 1, err); 331 if (*err) 332 goto drop_data_sem; 333 334 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset, 335 block_len_in_page, 1, err); 336 if (*err) 337 goto drop_data_sem; 338 339 if (!unwritten) { 340 ext4_double_up_write_data_sem(orig_inode, donor_inode); 341 goto data_copy; 342 } 343 if (!filemap_release_folio(folio[0], 0) || 344 !filemap_release_folio(folio[1], 0)) { 345 *err = -EBUSY; 346 goto drop_data_sem; 347 } 348 replaced_count = ext4_swap_extents(handle, orig_inode, 349 donor_inode, orig_blk_offset, 350 donor_blk_offset, 351 block_len_in_page, 1, err); 352 drop_data_sem: 353 ext4_double_up_write_data_sem(orig_inode, donor_inode); 354 goto unlock_folios; 355 } 356data_copy: 357 *err = mext_page_mkuptodate(folio[0], from, from + replaced_size); 358 if (*err) 359 goto unlock_folios; 360 361 /* At this point all buffers in range are uptodate, old mapping layout 362 * is no longer required, try to drop it now. */ 363 if (!filemap_release_folio(folio[0], 0) || 364 !filemap_release_folio(folio[1], 0)) { 365 *err = -EBUSY; 366 goto unlock_folios; 367 } 368 ext4_double_down_write_data_sem(orig_inode, donor_inode); 369 replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, 370 orig_blk_offset, donor_blk_offset, 371 block_len_in_page, 1, err); 372 ext4_double_up_write_data_sem(orig_inode, donor_inode); 373 if (*err) { 374 if (replaced_count) { 375 block_len_in_page = replaced_count; 376 replaced_size = 377 block_len_in_page << orig_inode->i_blkbits; 378 } else 379 goto unlock_folios; 380 } 381 /* Perform all necessary steps similar write_begin()/write_end() 382 * but keeping in mind that i_size will not change */ 383 if (!folio_buffers(folio[0])) 384 create_empty_buffers(&folio[0]->page, 1 << orig_inode->i_blkbits, 0); 385 bh = folio_buffers(folio[0]); 386 for (i = 0; i < data_offset_in_page; i++) 387 bh = bh->b_this_page; 388 for (i = 0; i < block_len_in_page; i++) { 389 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); 390 if (*err < 0) 391 goto repair_branches; 392 bh = bh->b_this_page; 393 } 394 395 block_commit_write(&folio[0]->page, from, from + replaced_size); 396 397 /* Even in case of data=writeback it is reasonable to pin 398 * inode to transaction, to prevent unexpected data loss */ 399 *err = ext4_jbd2_inode_add_write(handle, orig_inode, 400 (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size); 401 402unlock_folios: 403 folio_unlock(folio[0]); 404 folio_put(folio[0]); 405 folio_unlock(folio[1]); 406 folio_put(folio[1]); 407stop_journal: 408 ext4_journal_stop(handle); 409 if (*err == -ENOSPC && 410 ext4_should_retry_alloc(sb, &retries)) 411 goto again; 412 /* Buffer was busy because probably is pinned to journal transaction, 413 * force transaction commit may help to free it. */ 414 if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal && 415 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal)) 416 goto again; 417 return replaced_count; 418 419repair_branches: 420 /* 421 * This should never ever happen! 422 * Extents are swapped already, but we are not able to copy data. 423 * Try to swap extents to it's original places 424 */ 425 ext4_double_down_write_data_sem(orig_inode, donor_inode); 426 replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode, 427 orig_blk_offset, donor_blk_offset, 428 block_len_in_page, 0, &err2); 429 ext4_double_up_write_data_sem(orig_inode, donor_inode); 430 if (replaced_count != block_len_in_page) { 431 ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset), 432 EIO, "Unable to copy data block," 433 " data will be lost."); 434 *err = -EIO; 435 } 436 replaced_count = 0; 437 goto unlock_folios; 438} 439 440/** 441 * mext_check_arguments - Check whether move extent can be done 442 * 443 * @orig_inode: original inode 444 * @donor_inode: donor inode 445 * @orig_start: logical start offset in block for orig 446 * @donor_start: logical start offset in block for donor 447 * @len: the number of blocks to be moved 448 * 449 * Check the arguments of ext4_move_extents() whether the files can be 450 * exchanged with each other. 451 * Return 0 on success, or a negative error value on failure. 452 */ 453static int 454mext_check_arguments(struct inode *orig_inode, 455 struct inode *donor_inode, __u64 orig_start, 456 __u64 donor_start, __u64 *len) 457{ 458 __u64 orig_eof, donor_eof; 459 unsigned int blkbits = orig_inode->i_blkbits; 460 unsigned int blocksize = 1 << blkbits; 461 462 orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits; 463 donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits; 464 465 466 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { 467 ext4_debug("ext4 move extent: suid or sgid is set" 468 " to donor file [ino:orig %lu, donor %lu]\n", 469 orig_inode->i_ino, donor_inode->i_ino); 470 return -EINVAL; 471 } 472 473 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) 474 return -EPERM; 475 476 /* Ext4 move extent does not support swap files */ 477 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { 478 ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n", 479 orig_inode->i_ino, donor_inode->i_ino); 480 return -ETXTBSY; 481 } 482 483 if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) { 484 ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n", 485 orig_inode->i_ino, donor_inode->i_ino); 486 return -EOPNOTSUPP; 487 } 488 489 /* Ext4 move extent supports only extent based file */ 490 if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) { 491 ext4_debug("ext4 move extent: orig file is not extents " 492 "based file [ino:orig %lu]\n", orig_inode->i_ino); 493 return -EOPNOTSUPP; 494 } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) { 495 ext4_debug("ext4 move extent: donor file is not extents " 496 "based file [ino:donor %lu]\n", donor_inode->i_ino); 497 return -EOPNOTSUPP; 498 } 499 500 if ((!orig_inode->i_size) || (!donor_inode->i_size)) { 501 ext4_debug("ext4 move extent: File size is 0 byte\n"); 502 return -EINVAL; 503 } 504 505 /* Start offset should be same */ 506 if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) != 507 (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) { 508 ext4_debug("ext4 move extent: orig and donor's start " 509 "offsets are not aligned [ino:orig %lu, donor %lu]\n", 510 orig_inode->i_ino, donor_inode->i_ino); 511 return -EINVAL; 512 } 513 514 if ((orig_start >= EXT_MAX_BLOCKS) || 515 (donor_start >= EXT_MAX_BLOCKS) || 516 (*len > EXT_MAX_BLOCKS) || 517 (donor_start + *len >= EXT_MAX_BLOCKS) || 518 (orig_start + *len >= EXT_MAX_BLOCKS)) { 519 ext4_debug("ext4 move extent: Can't handle over [%u] blocks " 520 "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS, 521 orig_inode->i_ino, donor_inode->i_ino); 522 return -EINVAL; 523 } 524 if (orig_eof <= orig_start) 525 *len = 0; 526 else if (orig_eof < orig_start + *len - 1) 527 *len = orig_eof - orig_start; 528 if (donor_eof <= donor_start) 529 *len = 0; 530 else if (donor_eof < donor_start + *len - 1) 531 *len = donor_eof - donor_start; 532 if (!*len) { 533 ext4_debug("ext4 move extent: len should not be 0 " 534 "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino, 535 donor_inode->i_ino); 536 return -EINVAL; 537 } 538 539 return 0; 540} 541 542/** 543 * ext4_move_extents - Exchange the specified range of a file 544 * 545 * @o_filp: file structure of the original file 546 * @d_filp: file structure of the donor file 547 * @orig_blk: start offset in block for orig 548 * @donor_blk: start offset in block for donor 549 * @len: the number of blocks to be moved 550 * @moved_len: moved block length 551 * 552 * This function returns 0 and moved block length is set in moved_len 553 * if succeed, otherwise returns error value. 554 * 555 */ 556int 557ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk, 558 __u64 donor_blk, __u64 len, __u64 *moved_len) 559{ 560 struct inode *orig_inode = file_inode(o_filp); 561 struct inode *donor_inode = file_inode(d_filp); 562 struct ext4_ext_path *path = NULL; 563 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 564 ext4_lblk_t o_end, o_start = orig_blk; 565 ext4_lblk_t d_start = donor_blk; 566 int ret; 567 568 if (orig_inode->i_sb != donor_inode->i_sb) { 569 ext4_debug("ext4 move extent: The argument files " 570 "should be in same FS [ino:orig %lu, donor %lu]\n", 571 orig_inode->i_ino, donor_inode->i_ino); 572 return -EINVAL; 573 } 574 575 /* orig and donor should be different inodes */ 576 if (orig_inode == donor_inode) { 577 ext4_debug("ext4 move extent: The argument files should not " 578 "be same inode [ino:orig %lu, donor %lu]\n", 579 orig_inode->i_ino, donor_inode->i_ino); 580 return -EINVAL; 581 } 582 583 /* Regular file check */ 584 if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) { 585 ext4_debug("ext4 move extent: The argument files should be " 586 "regular file [ino:orig %lu, donor %lu]\n", 587 orig_inode->i_ino, donor_inode->i_ino); 588 return -EINVAL; 589 } 590 591 /* TODO: it's not obvious how to swap blocks for inodes with full 592 journaling enabled */ 593 if (ext4_should_journal_data(orig_inode) || 594 ext4_should_journal_data(donor_inode)) { 595 ext4_msg(orig_inode->i_sb, KERN_ERR, 596 "Online defrag not supported with data journaling"); 597 return -EOPNOTSUPP; 598 } 599 600 if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) { 601 ext4_msg(orig_inode->i_sb, KERN_ERR, 602 "Online defrag not supported for encrypted files"); 603 return -EOPNOTSUPP; 604 } 605 606 /* Protect orig and donor inodes against a truncate */ 607 lock_two_nondirectories(orig_inode, donor_inode); 608 609 /* Wait for all existing dio workers */ 610 inode_dio_wait(orig_inode); 611 inode_dio_wait(donor_inode); 612 613 /* Protect extent tree against block allocations via delalloc */ 614 ext4_double_down_write_data_sem(orig_inode, donor_inode); 615 /* Check the filesystem environment whether move_extent can be done */ 616 ret = mext_check_arguments(orig_inode, donor_inode, orig_blk, 617 donor_blk, &len); 618 if (ret) 619 goto out; 620 o_end = o_start + len; 621 622 *moved_len = 0; 623 while (o_start < o_end) { 624 struct ext4_extent *ex; 625 ext4_lblk_t cur_blk, next_blk; 626 pgoff_t orig_page_index, donor_page_index; 627 int offset_in_page; 628 int unwritten, cur_len; 629 630 ret = get_ext_path(orig_inode, o_start, &path); 631 if (ret) 632 goto out; 633 ex = path[path->p_depth].p_ext; 634 cur_blk = le32_to_cpu(ex->ee_block); 635 cur_len = ext4_ext_get_actual_len(ex); 636 /* Check hole before the start pos */ 637 if (cur_blk + cur_len - 1 < o_start) { 638 next_blk = ext4_ext_next_allocated_block(path); 639 if (next_blk == EXT_MAX_BLOCKS) { 640 ret = -ENODATA; 641 goto out; 642 } 643 d_start += next_blk - o_start; 644 o_start = next_blk; 645 continue; 646 /* Check hole after the start pos */ 647 } else if (cur_blk > o_start) { 648 /* Skip hole */ 649 d_start += cur_blk - o_start; 650 o_start = cur_blk; 651 /* Extent inside requested range ?*/ 652 if (cur_blk >= o_end) 653 goto out; 654 } else { /* in_range(o_start, o_blk, o_len) */ 655 cur_len += cur_blk - o_start; 656 } 657 unwritten = ext4_ext_is_unwritten(ex); 658 if (o_end - o_start < cur_len) 659 cur_len = o_end - o_start; 660 661 orig_page_index = o_start >> (PAGE_SHIFT - 662 orig_inode->i_blkbits); 663 donor_page_index = d_start >> (PAGE_SHIFT - 664 donor_inode->i_blkbits); 665 offset_in_page = o_start % blocks_per_page; 666 if (cur_len > blocks_per_page - offset_in_page) 667 cur_len = blocks_per_page - offset_in_page; 668 /* 669 * Up semaphore to avoid following problems: 670 * a. transaction deadlock among ext4_journal_start, 671 * ->write_begin via pagefault, and jbd2_journal_commit 672 * b. racing with ->read_folio, ->write_begin, and 673 * ext4_get_block in move_extent_per_page 674 */ 675 ext4_double_up_write_data_sem(orig_inode, donor_inode); 676 /* Swap original branches with new branches */ 677 *moved_len += move_extent_per_page(o_filp, donor_inode, 678 orig_page_index, donor_page_index, 679 offset_in_page, cur_len, 680 unwritten, &ret); 681 ext4_double_down_write_data_sem(orig_inode, donor_inode); 682 if (ret < 0) 683 break; 684 o_start += cur_len; 685 d_start += cur_len; 686 } 687 688out: 689 if (*moved_len) { 690 ext4_discard_preallocations(orig_inode, 0); 691 ext4_discard_preallocations(donor_inode, 0); 692 } 693 694 ext4_free_ext_path(path); 695 ext4_double_up_write_data_sem(orig_inode, donor_inode); 696 unlock_two_nondirectories(orig_inode, donor_inode); 697 698 return ret; 699} 700