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 "ext4_jbd2.h" 12 #include "ext4.h" 13 #include "ext4_extents.h" 14 15 /** 16 * get_ext_path() - Find an extent path for designated logical block number. 17 * @inode: inode to be searched 18 * @lblock: logical block number to find an extent path 19 * @ppath: pointer to an extent path pointer (for output) 20 * 21 * ext4_find_extent wrapper. Return 0 on success, or a negative error value 22 * on failure. 23 */ 24 static inline int 25 get_ext_path(struct inode *inode, ext4_lblk_t lblock, 26 struct ext4_ext_path **ppath) 27 { 28 struct ext4_ext_path *path; 29 30 path = ext4_find_extent(inode, lblock, ppath, EXT4_EX_NOCACHE); 31 if (IS_ERR(path)) 32 return PTR_ERR(path); 33 if (path[ext_depth(inode)].p_ext == NULL) { 34 ext4_ext_drop_refs(path); 35 kfree(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 ext4_ext_drop_refs(path); 106 } 107 ret = 1; 108 out: 109 ext4_ext_drop_refs(path); 110 kfree(path); 111 return ret; 112 } 113 114 /** 115 * mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2 116 * 117 * @inode1: the inode structure 118 * @inode2: the inode structure 119 * @index1: page index 120 * @index2: page index 121 * @page: result page vector 122 * 123 * Grab two locked pages for inode's by inode order 124 */ 125 static int 126 mext_page_double_lock(struct inode *inode1, struct inode *inode2, 127 pgoff_t index1, pgoff_t index2, struct page *page[2]) 128 { 129 struct address_space *mapping[2]; 130 unsigned fl = AOP_FLAG_NOFS; 131 132 BUG_ON(!inode1 || !inode2); 133 if (inode1 < inode2) { 134 mapping[0] = inode1->i_mapping; 135 mapping[1] = inode2->i_mapping; 136 } else { 137 swap(index1, index2); 138 mapping[0] = inode2->i_mapping; 139 mapping[1] = inode1->i_mapping; 140 } 141 142 page[0] = grab_cache_page_write_begin(mapping[0], index1, fl); 143 if (!page[0]) 144 return -ENOMEM; 145 146 page[1] = grab_cache_page_write_begin(mapping[1], index2, fl); 147 if (!page[1]) { 148 unlock_page(page[0]); 149 put_page(page[0]); 150 return -ENOMEM; 151 } 152 /* 153 * grab_cache_page_write_begin() may not wait on page's writeback if 154 * BDI not demand that. But it is reasonable to be very conservative 155 * here and explicitly wait on page's writeback 156 */ 157 wait_on_page_writeback(page[0]); 158 wait_on_page_writeback(page[1]); 159 if (inode1 > inode2) 160 swap(page[0], page[1]); 161 162 return 0; 163 } 164 165 /* Force page buffers uptodate w/o dropping page's lock */ 166 static int 167 mext_page_mkuptodate(struct page *page, unsigned from, unsigned to) 168 { 169 struct inode *inode = page->mapping->host; 170 sector_t block; 171 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; 172 unsigned int blocksize, block_start, block_end; 173 int i, err, nr = 0, partial = 0; 174 BUG_ON(!PageLocked(page)); 175 BUG_ON(PageWriteback(page)); 176 177 if (PageUptodate(page)) 178 return 0; 179 180 blocksize = i_blocksize(inode); 181 if (!page_has_buffers(page)) 182 create_empty_buffers(page, blocksize, 0); 183 184 head = page_buffers(page); 185 block = (sector_t)page->index << (PAGE_SHIFT - inode->i_blkbits); 186 for (bh = head, block_start = 0; bh != head || !block_start; 187 block++, block_start = block_end, bh = bh->b_this_page) { 188 block_end = block_start + blocksize; 189 if (block_end <= from || block_start >= to) { 190 if (!buffer_uptodate(bh)) 191 partial = 1; 192 continue; 193 } 194 if (buffer_uptodate(bh)) 195 continue; 196 if (!buffer_mapped(bh)) { 197 err = ext4_get_block(inode, block, bh, 0); 198 if (err) { 199 SetPageError(page); 200 return err; 201 } 202 if (!buffer_mapped(bh)) { 203 zero_user(page, block_start, blocksize); 204 set_buffer_uptodate(bh); 205 continue; 206 } 207 } 208 BUG_ON(nr >= MAX_BUF_PER_PAGE); 209 arr[nr++] = bh; 210 } 211 /* No io required */ 212 if (!nr) 213 goto out; 214 215 for (i = 0; i < nr; i++) { 216 bh = arr[i]; 217 if (!bh_uptodate_or_lock(bh)) { 218 err = ext4_read_bh(bh, 0, NULL); 219 if (err) 220 return err; 221 } 222 } 223 out: 224 if (!partial) 225 SetPageUptodate(page); 226 return 0; 227 } 228 229 /** 230 * move_extent_per_page - Move extent data per page 231 * 232 * @o_filp: file structure of original file 233 * @donor_inode: donor inode 234 * @orig_page_offset: page index on original file 235 * @donor_page_offset: page index on donor file 236 * @data_offset_in_page: block index where data swapping starts 237 * @block_len_in_page: the number of blocks to be swapped 238 * @unwritten: orig extent is unwritten or not 239 * @err: pointer to save return value 240 * 241 * Save the data in original inode blocks and replace original inode extents 242 * with donor inode extents by calling ext4_swap_extents(). 243 * Finally, write out the saved data in new original inode blocks. Return 244 * replaced block count. 245 */ 246 static int 247 move_extent_per_page(struct file *o_filp, struct inode *donor_inode, 248 pgoff_t orig_page_offset, pgoff_t donor_page_offset, 249 int data_offset_in_page, 250 int block_len_in_page, int unwritten, int *err) 251 { 252 struct inode *orig_inode = file_inode(o_filp); 253 struct page *pagep[2] = {NULL, NULL}; 254 handle_t *handle; 255 ext4_lblk_t orig_blk_offset, donor_blk_offset; 256 unsigned long blocksize = orig_inode->i_sb->s_blocksize; 257 unsigned int tmp_data_size, data_size, replaced_size; 258 int i, err2, jblocks, retries = 0; 259 int replaced_count = 0; 260 int from = data_offset_in_page << orig_inode->i_blkbits; 261 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; 262 struct super_block *sb = orig_inode->i_sb; 263 struct buffer_head *bh = NULL; 264 265 /* 266 * It needs twice the amount of ordinary journal buffers because 267 * inode and donor_inode may change each different metadata blocks. 268 */ 269 again: 270 *err = 0; 271 jblocks = ext4_writepage_trans_blocks(orig_inode) * 2; 272 handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks); 273 if (IS_ERR(handle)) { 274 *err = PTR_ERR(handle); 275 return 0; 276 } 277 278 orig_blk_offset = orig_page_offset * blocks_per_page + 279 data_offset_in_page; 280 281 donor_blk_offset = donor_page_offset * blocks_per_page + 282 data_offset_in_page; 283 284 /* Calculate data_size */ 285 if ((orig_blk_offset + block_len_in_page - 1) == 286 ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) { 287 /* Replace the last block */ 288 tmp_data_size = orig_inode->i_size & (blocksize - 1); 289 /* 290 * If data_size equal zero, it shows data_size is multiples of 291 * blocksize. So we set appropriate value. 292 */ 293 if (tmp_data_size == 0) 294 tmp_data_size = blocksize; 295 296 data_size = tmp_data_size + 297 ((block_len_in_page - 1) << orig_inode->i_blkbits); 298 } else 299 data_size = block_len_in_page << orig_inode->i_blkbits; 300 301 replaced_size = data_size; 302 303 *err = mext_page_double_lock(orig_inode, donor_inode, orig_page_offset, 304 donor_page_offset, pagep); 305 if (unlikely(*err < 0)) 306 goto stop_journal; 307 /* 308 * If orig extent was unwritten it can become initialized 309 * at any time after i_data_sem was dropped, in order to 310 * serialize with delalloc we have recheck extent while we 311 * hold page's lock, if it is still the case data copy is not 312 * necessary, just swap data blocks between orig and donor. 313 */ 314 if (unwritten) { 315 ext4_double_down_write_data_sem(orig_inode, donor_inode); 316 /* If any of extents in range became initialized we have to 317 * fallback to data copying */ 318 unwritten = mext_check_coverage(orig_inode, orig_blk_offset, 319 block_len_in_page, 1, err); 320 if (*err) 321 goto drop_data_sem; 322 323 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset, 324 block_len_in_page, 1, err); 325 if (*err) 326 goto drop_data_sem; 327 328 if (!unwritten) { 329 ext4_double_up_write_data_sem(orig_inode, donor_inode); 330 goto data_copy; 331 } 332 if ((page_has_private(pagep[0]) && 333 !try_to_release_page(pagep[0], 0)) || 334 (page_has_private(pagep[1]) && 335 !try_to_release_page(pagep[1], 0))) { 336 *err = -EBUSY; 337 goto drop_data_sem; 338 } 339 replaced_count = ext4_swap_extents(handle, orig_inode, 340 donor_inode, orig_blk_offset, 341 donor_blk_offset, 342 block_len_in_page, 1, err); 343 drop_data_sem: 344 ext4_double_up_write_data_sem(orig_inode, donor_inode); 345 goto unlock_pages; 346 } 347 data_copy: 348 *err = mext_page_mkuptodate(pagep[0], from, from + replaced_size); 349 if (*err) 350 goto unlock_pages; 351 352 /* At this point all buffers in range are uptodate, old mapping layout 353 * is no longer required, try to drop it now. */ 354 if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) || 355 (page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) { 356 *err = -EBUSY; 357 goto unlock_pages; 358 } 359 ext4_double_down_write_data_sem(orig_inode, donor_inode); 360 replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, 361 orig_blk_offset, donor_blk_offset, 362 block_len_in_page, 1, err); 363 ext4_double_up_write_data_sem(orig_inode, donor_inode); 364 if (*err) { 365 if (replaced_count) { 366 block_len_in_page = replaced_count; 367 replaced_size = 368 block_len_in_page << orig_inode->i_blkbits; 369 } else 370 goto unlock_pages; 371 } 372 /* Perform all necessary steps similar write_begin()/write_end() 373 * but keeping in mind that i_size will not change */ 374 if (!page_has_buffers(pagep[0])) 375 create_empty_buffers(pagep[0], 1 << orig_inode->i_blkbits, 0); 376 bh = page_buffers(pagep[0]); 377 for (i = 0; i < data_offset_in_page; i++) 378 bh = bh->b_this_page; 379 for (i = 0; i < block_len_in_page; i++) { 380 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); 381 if (*err < 0) 382 break; 383 bh = bh->b_this_page; 384 } 385 if (!*err) 386 *err = block_commit_write(pagep[0], from, from + replaced_size); 387 388 if (unlikely(*err < 0)) 389 goto repair_branches; 390 391 /* Even in case of data=writeback it is reasonable to pin 392 * inode to transaction, to prevent unexpected data loss */ 393 *err = ext4_jbd2_inode_add_write(handle, orig_inode, 394 (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size); 395 396 unlock_pages: 397 unlock_page(pagep[0]); 398 put_page(pagep[0]); 399 unlock_page(pagep[1]); 400 put_page(pagep[1]); 401 stop_journal: 402 ext4_journal_stop(handle); 403 if (*err == -ENOSPC && 404 ext4_should_retry_alloc(sb, &retries)) 405 goto again; 406 /* Buffer was busy because probably is pinned to journal transaction, 407 * force transaction commit may help to free it. */ 408 if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal && 409 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal)) 410 goto again; 411 return replaced_count; 412 413 repair_branches: 414 /* 415 * This should never ever happen! 416 * Extents are swapped already, but we are not able to copy data. 417 * Try to swap extents to it's original places 418 */ 419 ext4_double_down_write_data_sem(orig_inode, donor_inode); 420 replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode, 421 orig_blk_offset, donor_blk_offset, 422 block_len_in_page, 0, &err2); 423 ext4_double_up_write_data_sem(orig_inode, donor_inode); 424 if (replaced_count != block_len_in_page) { 425 ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset), 426 EIO, "Unable to copy data block," 427 " data will be lost."); 428 *err = -EIO; 429 } 430 replaced_count = 0; 431 goto unlock_pages; 432 } 433 434 /** 435 * mext_check_arguments - Check whether move extent can be done 436 * 437 * @orig_inode: original inode 438 * @donor_inode: donor inode 439 * @orig_start: logical start offset in block for orig 440 * @donor_start: logical start offset in block for donor 441 * @len: the number of blocks to be moved 442 * 443 * Check the arguments of ext4_move_extents() whether the files can be 444 * exchanged with each other. 445 * Return 0 on success, or a negative error value on failure. 446 */ 447 static int 448 mext_check_arguments(struct inode *orig_inode, 449 struct inode *donor_inode, __u64 orig_start, 450 __u64 donor_start, __u64 *len) 451 { 452 __u64 orig_eof, donor_eof; 453 unsigned int blkbits = orig_inode->i_blkbits; 454 unsigned int blocksize = 1 << blkbits; 455 456 orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits; 457 donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits; 458 459 460 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { 461 ext4_debug("ext4 move extent: suid or sgid is set" 462 " to donor file [ino:orig %lu, donor %lu]\n", 463 orig_inode->i_ino, donor_inode->i_ino); 464 return -EINVAL; 465 } 466 467 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) 468 return -EPERM; 469 470 /* Ext4 move extent does not support swapfile */ 471 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { 472 ext4_debug("ext4 move extent: The argument files should " 473 "not be swapfile [ino:orig %lu, donor %lu]\n", 474 orig_inode->i_ino, donor_inode->i_ino); 475 return -EBUSY; 476 } 477 478 if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) { 479 ext4_debug("ext4 move extent: The argument files should " 480 "not be quota files [ino:orig %lu, donor %lu]\n", 481 orig_inode->i_ino, donor_inode->i_ino); 482 return -EBUSY; 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 next_blk = ext4_ext_next_allocated_block(path); 630 cur_blk = le32_to_cpu(ex->ee_block); 631 cur_len = ext4_ext_get_actual_len(ex); 632 /* Check hole before the start pos */ 633 if (cur_blk + cur_len - 1 < o_start) { 634 if (next_blk == EXT_MAX_BLOCKS) { 635 o_start = o_end; 636 ret = -ENODATA; 637 goto out; 638 } 639 d_start += next_blk - o_start; 640 o_start = next_blk; 641 continue; 642 /* Check hole after the start pos */ 643 } else if (cur_blk > o_start) { 644 /* Skip hole */ 645 d_start += cur_blk - o_start; 646 o_start = cur_blk; 647 /* Extent inside requested range ?*/ 648 if (cur_blk >= o_end) 649 goto out; 650 } else { /* in_range(o_start, o_blk, o_len) */ 651 cur_len += cur_blk - o_start; 652 } 653 unwritten = ext4_ext_is_unwritten(ex); 654 if (o_end - o_start < cur_len) 655 cur_len = o_end - o_start; 656 657 orig_page_index = o_start >> (PAGE_SHIFT - 658 orig_inode->i_blkbits); 659 donor_page_index = d_start >> (PAGE_SHIFT - 660 donor_inode->i_blkbits); 661 offset_in_page = o_start % blocks_per_page; 662 if (cur_len > blocks_per_page- offset_in_page) 663 cur_len = blocks_per_page - offset_in_page; 664 /* 665 * Up semaphore to avoid following problems: 666 * a. transaction deadlock among ext4_journal_start, 667 * ->write_begin via pagefault, and jbd2_journal_commit 668 * b. racing with ->readpage, ->write_begin, and ext4_get_block 669 * in move_extent_per_page 670 */ 671 ext4_double_up_write_data_sem(orig_inode, donor_inode); 672 /* Swap original branches with new branches */ 673 move_extent_per_page(o_filp, donor_inode, 674 orig_page_index, donor_page_index, 675 offset_in_page, cur_len, 676 unwritten, &ret); 677 ext4_double_down_write_data_sem(orig_inode, donor_inode); 678 if (ret < 0) 679 break; 680 o_start += cur_len; 681 d_start += cur_len; 682 } 683 *moved_len = o_start - orig_blk; 684 if (*moved_len > len) 685 *moved_len = len; 686 687 out: 688 if (*moved_len) { 689 ext4_discard_preallocations(orig_inode, 0); 690 ext4_discard_preallocations(donor_inode, 0); 691 } 692 693 ext4_ext_drop_refs(path); 694 kfree(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