1 /* 2 * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd. 3 * Written by Takashi Sato <t-sato@yk.jp.nec.com> 4 * Akira Fujita <a-fujita@rs.jp.nec.com> 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of version 2.1 of the GNU Lesser General Public License 8 * as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 */ 15 16 #include <linux/fs.h> 17 #include <linux/quotaops.h> 18 #include <linux/slab.h> 19 #include "ext4_jbd2.h" 20 #include "ext4.h" 21 #include "ext4_extents.h" 22 23 /** 24 * get_ext_path - Find an extent path for designated logical block number. 25 * 26 * @inode: an inode which is searched 27 * @lblock: logical block number to find an extent path 28 * @path: pointer to an extent path pointer (for output) 29 * 30 * ext4_ext_find_extent wrapper. Return 0 on success, or a negative error value 31 * on failure. 32 */ 33 static inline int 34 get_ext_path(struct inode *inode, ext4_lblk_t lblock, 35 struct ext4_ext_path **orig_path) 36 { 37 int ret = 0; 38 struct ext4_ext_path *path; 39 40 path = ext4_ext_find_extent(inode, lblock, *orig_path, EXT4_EX_NOCACHE); 41 if (IS_ERR(path)) 42 ret = PTR_ERR(path); 43 else if (path[ext_depth(inode)].p_ext == NULL) 44 ret = -ENODATA; 45 else 46 *orig_path = path; 47 48 return ret; 49 } 50 51 /** 52 * copy_extent_status - Copy the extent's initialization status 53 * 54 * @src: an extent for getting initialize status 55 * @dest: an extent to be set the status 56 */ 57 static void 58 copy_extent_status(struct ext4_extent *src, struct ext4_extent *dest) 59 { 60 if (ext4_ext_is_unwritten(src)) 61 ext4_ext_mark_unwritten(dest); 62 else 63 dest->ee_len = cpu_to_le16(ext4_ext_get_actual_len(dest)); 64 } 65 66 /** 67 * mext_next_extent - Search for the next extent and set it to "extent" 68 * 69 * @inode: inode which is searched 70 * @path: this will obtain data for the next extent 71 * @extent: pointer to the next extent we have just gotten 72 * 73 * Search the next extent in the array of ext4_ext_path structure (@path) 74 * and set it to ext4_extent structure (@extent). In addition, the member of 75 * @path (->p_ext) also points the next extent. Return 0 on success, 1 if 76 * ext4_ext_path structure refers to the last extent, or a negative error 77 * value on failure. 78 */ 79 int 80 mext_next_extent(struct inode *inode, struct ext4_ext_path *path, 81 struct ext4_extent **extent) 82 { 83 struct ext4_extent_header *eh; 84 int ppos, leaf_ppos = path->p_depth; 85 86 ppos = leaf_ppos; 87 if (EXT_LAST_EXTENT(path[ppos].p_hdr) > path[ppos].p_ext) { 88 /* leaf block */ 89 *extent = ++path[ppos].p_ext; 90 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext); 91 return 0; 92 } 93 94 while (--ppos >= 0) { 95 if (EXT_LAST_INDEX(path[ppos].p_hdr) > 96 path[ppos].p_idx) { 97 int cur_ppos = ppos; 98 99 /* index block */ 100 path[ppos].p_idx++; 101 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx); 102 if (path[ppos+1].p_bh) 103 brelse(path[ppos+1].p_bh); 104 path[ppos+1].p_bh = 105 sb_bread(inode->i_sb, path[ppos].p_block); 106 if (!path[ppos+1].p_bh) 107 return -EIO; 108 path[ppos+1].p_hdr = 109 ext_block_hdr(path[ppos+1].p_bh); 110 111 /* Halfway index block */ 112 while (++cur_ppos < leaf_ppos) { 113 path[cur_ppos].p_idx = 114 EXT_FIRST_INDEX(path[cur_ppos].p_hdr); 115 path[cur_ppos].p_block = 116 ext4_idx_pblock(path[cur_ppos].p_idx); 117 if (path[cur_ppos+1].p_bh) 118 brelse(path[cur_ppos+1].p_bh); 119 path[cur_ppos+1].p_bh = sb_bread(inode->i_sb, 120 path[cur_ppos].p_block); 121 if (!path[cur_ppos+1].p_bh) 122 return -EIO; 123 path[cur_ppos+1].p_hdr = 124 ext_block_hdr(path[cur_ppos+1].p_bh); 125 } 126 127 path[leaf_ppos].p_ext = *extent = NULL; 128 129 eh = path[leaf_ppos].p_hdr; 130 if (le16_to_cpu(eh->eh_entries) == 0) 131 /* empty leaf is found */ 132 return -ENODATA; 133 134 /* leaf block */ 135 path[leaf_ppos].p_ext = *extent = 136 EXT_FIRST_EXTENT(path[leaf_ppos].p_hdr); 137 path[leaf_ppos].p_block = 138 ext4_ext_pblock(path[leaf_ppos].p_ext); 139 return 0; 140 } 141 } 142 /* We found the last extent */ 143 return 1; 144 } 145 146 /** 147 * ext4_double_down_write_data_sem - Acquire two inodes' write lock 148 * of i_data_sem 149 * 150 * Acquire write lock of i_data_sem of the two inodes 151 */ 152 void 153 ext4_double_down_write_data_sem(struct inode *first, struct inode *second) 154 { 155 if (first < second) { 156 down_write(&EXT4_I(first)->i_data_sem); 157 down_write_nested(&EXT4_I(second)->i_data_sem, SINGLE_DEPTH_NESTING); 158 } else { 159 down_write(&EXT4_I(second)->i_data_sem); 160 down_write_nested(&EXT4_I(first)->i_data_sem, SINGLE_DEPTH_NESTING); 161 162 } 163 } 164 165 /** 166 * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem 167 * 168 * @orig_inode: original inode structure to be released its lock first 169 * @donor_inode: donor inode structure to be released its lock second 170 * Release write lock of i_data_sem of two inodes (orig and donor). 171 */ 172 void 173 ext4_double_up_write_data_sem(struct inode *orig_inode, 174 struct inode *donor_inode) 175 { 176 up_write(&EXT4_I(orig_inode)->i_data_sem); 177 up_write(&EXT4_I(donor_inode)->i_data_sem); 178 } 179 180 /** 181 * mext_insert_across_blocks - Insert extents across leaf block 182 * 183 * @handle: journal handle 184 * @orig_inode: original inode 185 * @o_start: first original extent to be changed 186 * @o_end: last original extent to be changed 187 * @start_ext: first new extent to be inserted 188 * @new_ext: middle of new extent to be inserted 189 * @end_ext: last new extent to be inserted 190 * 191 * Allocate a new leaf block and insert extents into it. Return 0 on success, 192 * or a negative error value on failure. 193 */ 194 static int 195 mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode, 196 struct ext4_extent *o_start, struct ext4_extent *o_end, 197 struct ext4_extent *start_ext, struct ext4_extent *new_ext, 198 struct ext4_extent *end_ext) 199 { 200 struct ext4_ext_path *orig_path = NULL; 201 ext4_lblk_t eblock = 0; 202 int new_flag = 0; 203 int end_flag = 0; 204 int err = 0; 205 206 if (start_ext->ee_len && new_ext->ee_len && end_ext->ee_len) { 207 if (o_start == o_end) { 208 209 /* start_ext new_ext end_ext 210 * donor |---------|-----------|--------| 211 * orig |------------------------------| 212 */ 213 end_flag = 1; 214 } else { 215 216 /* start_ext new_ext end_ext 217 * donor |---------|----------|---------| 218 * orig |---------------|--------------| 219 */ 220 o_end->ee_block = end_ext->ee_block; 221 o_end->ee_len = end_ext->ee_len; 222 ext4_ext_store_pblock(o_end, ext4_ext_pblock(end_ext)); 223 } 224 225 o_start->ee_len = start_ext->ee_len; 226 eblock = le32_to_cpu(start_ext->ee_block); 227 new_flag = 1; 228 229 } else if (start_ext->ee_len && new_ext->ee_len && 230 !end_ext->ee_len && o_start == o_end) { 231 232 /* start_ext new_ext 233 * donor |--------------|---------------| 234 * orig |------------------------------| 235 */ 236 o_start->ee_len = start_ext->ee_len; 237 eblock = le32_to_cpu(start_ext->ee_block); 238 new_flag = 1; 239 240 } else if (!start_ext->ee_len && new_ext->ee_len && 241 end_ext->ee_len && o_start == o_end) { 242 243 /* new_ext end_ext 244 * donor |--------------|---------------| 245 * orig |------------------------------| 246 */ 247 o_end->ee_block = end_ext->ee_block; 248 o_end->ee_len = end_ext->ee_len; 249 ext4_ext_store_pblock(o_end, ext4_ext_pblock(end_ext)); 250 251 /* 252 * Set 0 to the extent block if new_ext was 253 * the first block. 254 */ 255 if (new_ext->ee_block) 256 eblock = le32_to_cpu(new_ext->ee_block); 257 258 new_flag = 1; 259 } else { 260 ext4_debug("ext4 move extent: Unexpected insert case\n"); 261 return -EIO; 262 } 263 264 if (new_flag) { 265 err = get_ext_path(orig_inode, eblock, &orig_path); 266 if (err) 267 goto out; 268 269 if (ext4_ext_insert_extent(handle, orig_inode, 270 orig_path, new_ext, 0)) 271 goto out; 272 } 273 274 if (end_flag) { 275 err = get_ext_path(orig_inode, 276 le32_to_cpu(end_ext->ee_block) - 1, &orig_path); 277 if (err) 278 goto out; 279 280 if (ext4_ext_insert_extent(handle, orig_inode, 281 orig_path, end_ext, 0)) 282 goto out; 283 } 284 out: 285 if (orig_path) { 286 ext4_ext_drop_refs(orig_path); 287 kfree(orig_path); 288 } 289 290 return err; 291 292 } 293 294 /** 295 * mext_insert_inside_block - Insert new extent to the extent block 296 * 297 * @o_start: first original extent to be moved 298 * @o_end: last original extent to be moved 299 * @start_ext: first new extent to be inserted 300 * @new_ext: middle of new extent to be inserted 301 * @end_ext: last new extent to be inserted 302 * @eh: extent header of target leaf block 303 * @range_to_move: used to decide how to insert extent 304 * 305 * Insert extents into the leaf block. The extent (@o_start) is overwritten 306 * by inserted extents. 307 */ 308 static void 309 mext_insert_inside_block(struct ext4_extent *o_start, 310 struct ext4_extent *o_end, 311 struct ext4_extent *start_ext, 312 struct ext4_extent *new_ext, 313 struct ext4_extent *end_ext, 314 struct ext4_extent_header *eh, 315 int range_to_move) 316 { 317 int i = 0; 318 unsigned long len; 319 320 /* Move the existing extents */ 321 if (range_to_move && o_end < EXT_LAST_EXTENT(eh)) { 322 len = (unsigned long)(EXT_LAST_EXTENT(eh) + 1) - 323 (unsigned long)(o_end + 1); 324 memmove(o_end + 1 + range_to_move, o_end + 1, len); 325 } 326 327 /* Insert start entry */ 328 if (start_ext->ee_len) 329 o_start[i++].ee_len = start_ext->ee_len; 330 331 /* Insert new entry */ 332 if (new_ext->ee_len) { 333 o_start[i] = *new_ext; 334 ext4_ext_store_pblock(&o_start[i++], ext4_ext_pblock(new_ext)); 335 } 336 337 /* Insert end entry */ 338 if (end_ext->ee_len) 339 o_start[i] = *end_ext; 340 341 /* Increment the total entries counter on the extent block */ 342 le16_add_cpu(&eh->eh_entries, range_to_move); 343 } 344 345 /** 346 * mext_insert_extents - Insert new extent 347 * 348 * @handle: journal handle 349 * @orig_inode: original inode 350 * @orig_path: path indicates first extent to be changed 351 * @o_start: first original extent to be changed 352 * @o_end: last original extent to be changed 353 * @start_ext: first new extent to be inserted 354 * @new_ext: middle of new extent to be inserted 355 * @end_ext: last new extent to be inserted 356 * 357 * Call the function to insert extents. If we cannot add more extents into 358 * the leaf block, we call mext_insert_across_blocks() to create a 359 * new leaf block. Otherwise call mext_insert_inside_block(). Return 0 360 * on success, or a negative error value on failure. 361 */ 362 static int 363 mext_insert_extents(handle_t *handle, struct inode *orig_inode, 364 struct ext4_ext_path *orig_path, 365 struct ext4_extent *o_start, 366 struct ext4_extent *o_end, 367 struct ext4_extent *start_ext, 368 struct ext4_extent *new_ext, 369 struct ext4_extent *end_ext) 370 { 371 struct ext4_extent_header *eh; 372 unsigned long need_slots, slots_range; 373 int range_to_move, depth, ret; 374 375 /* 376 * The extents need to be inserted 377 * start_extent + new_extent + end_extent. 378 */ 379 need_slots = (start_ext->ee_len ? 1 : 0) + (end_ext->ee_len ? 1 : 0) + 380 (new_ext->ee_len ? 1 : 0); 381 382 /* The number of slots between start and end */ 383 slots_range = ((unsigned long)(o_end + 1) - (unsigned long)o_start + 1) 384 / sizeof(struct ext4_extent); 385 386 /* Range to move the end of extent */ 387 range_to_move = need_slots - slots_range; 388 depth = orig_path->p_depth; 389 orig_path += depth; 390 eh = orig_path->p_hdr; 391 392 if (depth) { 393 /* Register to journal */ 394 BUFFER_TRACE(orig_path->p_bh, "get_write_access"); 395 ret = ext4_journal_get_write_access(handle, orig_path->p_bh); 396 if (ret) 397 return ret; 398 } 399 400 /* Expansion */ 401 if (range_to_move > 0 && 402 (range_to_move > le16_to_cpu(eh->eh_max) 403 - le16_to_cpu(eh->eh_entries))) { 404 405 ret = mext_insert_across_blocks(handle, orig_inode, o_start, 406 o_end, start_ext, new_ext, end_ext); 407 if (ret < 0) 408 return ret; 409 } else 410 mext_insert_inside_block(o_start, o_end, start_ext, new_ext, 411 end_ext, eh, range_to_move); 412 413 return ext4_ext_dirty(handle, orig_inode, orig_path); 414 } 415 416 /** 417 * mext_leaf_block - Move one leaf extent block into the inode. 418 * 419 * @handle: journal handle 420 * @orig_inode: original inode 421 * @orig_path: path indicates first extent to be changed 422 * @dext: donor extent 423 * @from: start offset on the target file 424 * 425 * In order to insert extents into the leaf block, we must divide the extent 426 * in the leaf block into three extents. The one is located to be inserted 427 * extents, and the others are located around it. 428 * 429 * Therefore, this function creates structures to save extents of the leaf 430 * block, and inserts extents by calling mext_insert_extents() with 431 * created extents. Return 0 on success, or a negative error value on failure. 432 */ 433 static int 434 mext_leaf_block(handle_t *handle, struct inode *orig_inode, 435 struct ext4_ext_path *orig_path, struct ext4_extent *dext, 436 ext4_lblk_t *from) 437 { 438 struct ext4_extent *oext, *o_start, *o_end, *prev_ext; 439 struct ext4_extent new_ext, start_ext, end_ext; 440 ext4_lblk_t new_ext_end; 441 int oext_alen, new_ext_alen, end_ext_alen; 442 int depth = ext_depth(orig_inode); 443 int ret; 444 445 start_ext.ee_block = end_ext.ee_block = 0; 446 o_start = o_end = oext = orig_path[depth].p_ext; 447 oext_alen = ext4_ext_get_actual_len(oext); 448 start_ext.ee_len = end_ext.ee_len = 0; 449 450 new_ext.ee_block = cpu_to_le32(*from); 451 ext4_ext_store_pblock(&new_ext, ext4_ext_pblock(dext)); 452 new_ext.ee_len = dext->ee_len; 453 new_ext_alen = ext4_ext_get_actual_len(&new_ext); 454 new_ext_end = le32_to_cpu(new_ext.ee_block) + new_ext_alen - 1; 455 456 /* 457 * Case: original extent is first 458 * oext |--------| 459 * new_ext |--| 460 * start_ext |--| 461 */ 462 if (le32_to_cpu(oext->ee_block) < le32_to_cpu(new_ext.ee_block) && 463 le32_to_cpu(new_ext.ee_block) < 464 le32_to_cpu(oext->ee_block) + oext_alen) { 465 start_ext.ee_len = cpu_to_le16(le32_to_cpu(new_ext.ee_block) - 466 le32_to_cpu(oext->ee_block)); 467 start_ext.ee_block = oext->ee_block; 468 copy_extent_status(oext, &start_ext); 469 } else if (oext > EXT_FIRST_EXTENT(orig_path[depth].p_hdr)) { 470 prev_ext = oext - 1; 471 /* 472 * We can merge new_ext into previous extent, 473 * if these are contiguous and same extent type. 474 */ 475 if (ext4_can_extents_be_merged(orig_inode, prev_ext, 476 &new_ext)) { 477 o_start = prev_ext; 478 start_ext.ee_len = cpu_to_le16( 479 ext4_ext_get_actual_len(prev_ext) + 480 new_ext_alen); 481 start_ext.ee_block = oext->ee_block; 482 copy_extent_status(prev_ext, &start_ext); 483 new_ext.ee_len = 0; 484 } 485 } 486 487 /* 488 * Case: new_ext_end must be less than oext 489 * oext |-----------| 490 * new_ext |-------| 491 */ 492 if (le32_to_cpu(oext->ee_block) + oext_alen - 1 < new_ext_end) { 493 EXT4_ERROR_INODE(orig_inode, 494 "new_ext_end(%u) should be less than or equal to " 495 "oext->ee_block(%u) + oext_alen(%d) - 1", 496 new_ext_end, le32_to_cpu(oext->ee_block), 497 oext_alen); 498 ret = -EIO; 499 goto out; 500 } 501 502 /* 503 * Case: new_ext is smaller than original extent 504 * oext |---------------| 505 * new_ext |-----------| 506 * end_ext |---| 507 */ 508 if (le32_to_cpu(oext->ee_block) <= new_ext_end && 509 new_ext_end < le32_to_cpu(oext->ee_block) + oext_alen - 1) { 510 end_ext.ee_len = 511 cpu_to_le16(le32_to_cpu(oext->ee_block) + 512 oext_alen - 1 - new_ext_end); 513 copy_extent_status(oext, &end_ext); 514 end_ext_alen = ext4_ext_get_actual_len(&end_ext); 515 ext4_ext_store_pblock(&end_ext, 516 (ext4_ext_pblock(o_end) + oext_alen - end_ext_alen)); 517 end_ext.ee_block = 518 cpu_to_le32(le32_to_cpu(o_end->ee_block) + 519 oext_alen - end_ext_alen); 520 } 521 522 ret = mext_insert_extents(handle, orig_inode, orig_path, o_start, 523 o_end, &start_ext, &new_ext, &end_ext); 524 out: 525 return ret; 526 } 527 528 /** 529 * mext_calc_swap_extents - Calculate extents for extent swapping. 530 * 531 * @tmp_dext: the extent that will belong to the original inode 532 * @tmp_oext: the extent that will belong to the donor inode 533 * @orig_off: block offset of original inode 534 * @donor_off: block offset of donor inode 535 * @max_count: the maximum length of extents 536 * 537 * Return 0 on success, or a negative error value on failure. 538 */ 539 static int 540 mext_calc_swap_extents(struct ext4_extent *tmp_dext, 541 struct ext4_extent *tmp_oext, 542 ext4_lblk_t orig_off, ext4_lblk_t donor_off, 543 ext4_lblk_t max_count) 544 { 545 ext4_lblk_t diff, orig_diff; 546 struct ext4_extent dext_old, oext_old; 547 548 BUG_ON(orig_off != donor_off); 549 550 /* original and donor extents have to cover the same block offset */ 551 if (orig_off < le32_to_cpu(tmp_oext->ee_block) || 552 le32_to_cpu(tmp_oext->ee_block) + 553 ext4_ext_get_actual_len(tmp_oext) - 1 < orig_off) 554 return -ENODATA; 555 556 if (orig_off < le32_to_cpu(tmp_dext->ee_block) || 557 le32_to_cpu(tmp_dext->ee_block) + 558 ext4_ext_get_actual_len(tmp_dext) - 1 < orig_off) 559 return -ENODATA; 560 561 dext_old = *tmp_dext; 562 oext_old = *tmp_oext; 563 564 /* When tmp_dext is too large, pick up the target range. */ 565 diff = donor_off - le32_to_cpu(tmp_dext->ee_block); 566 567 ext4_ext_store_pblock(tmp_dext, ext4_ext_pblock(tmp_dext) + diff); 568 le32_add_cpu(&tmp_dext->ee_block, diff); 569 le16_add_cpu(&tmp_dext->ee_len, -diff); 570 571 if (max_count < ext4_ext_get_actual_len(tmp_dext)) 572 tmp_dext->ee_len = cpu_to_le16(max_count); 573 574 orig_diff = orig_off - le32_to_cpu(tmp_oext->ee_block); 575 ext4_ext_store_pblock(tmp_oext, ext4_ext_pblock(tmp_oext) + orig_diff); 576 577 /* Adjust extent length if donor extent is larger than orig */ 578 if (ext4_ext_get_actual_len(tmp_dext) > 579 ext4_ext_get_actual_len(tmp_oext) - orig_diff) 580 tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_oext->ee_len) - 581 orig_diff); 582 583 tmp_oext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(tmp_dext)); 584 585 copy_extent_status(&oext_old, tmp_dext); 586 copy_extent_status(&dext_old, tmp_oext); 587 588 return 0; 589 } 590 591 /** 592 * mext_check_coverage - Check that all extents in range has the same type 593 * 594 * @inode: inode in question 595 * @from: block offset of inode 596 * @count: block count to be checked 597 * @unwritten: extents expected to be unwritten 598 * @err: pointer to save error value 599 * 600 * Return 1 if all extents in range has expected type, and zero otherwise. 601 */ 602 static int 603 mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count, 604 int unwritten, int *err) 605 { 606 struct ext4_ext_path *path = NULL; 607 struct ext4_extent *ext; 608 int ret = 0; 609 ext4_lblk_t last = from + count; 610 while (from < last) { 611 *err = get_ext_path(inode, from, &path); 612 if (*err) 613 goto out; 614 ext = path[ext_depth(inode)].p_ext; 615 if (unwritten != ext4_ext_is_unwritten(ext)) 616 goto out; 617 from += ext4_ext_get_actual_len(ext); 618 ext4_ext_drop_refs(path); 619 } 620 ret = 1; 621 out: 622 if (path) { 623 ext4_ext_drop_refs(path); 624 kfree(path); 625 } 626 return ret; 627 } 628 629 /** 630 * mext_replace_branches - Replace original extents with new extents 631 * 632 * @handle: journal handle 633 * @orig_inode: original inode 634 * @donor_inode: donor inode 635 * @from: block offset of orig_inode 636 * @count: block count to be replaced 637 * @err: pointer to save return value 638 * 639 * Replace original inode extents and donor inode extents page by page. 640 * We implement this replacement in the following three steps: 641 * 1. Save the block information of original and donor inodes into 642 * dummy extents. 643 * 2. Change the block information of original inode to point at the 644 * donor inode blocks. 645 * 3. Change the block information of donor inode to point at the saved 646 * original inode blocks in the dummy extents. 647 * 648 * Return replaced block count. 649 */ 650 static int 651 mext_replace_branches(handle_t *handle, struct inode *orig_inode, 652 struct inode *donor_inode, ext4_lblk_t from, 653 ext4_lblk_t count, int *err) 654 { 655 struct ext4_ext_path *orig_path = NULL; 656 struct ext4_ext_path *donor_path = NULL; 657 struct ext4_extent *oext, *dext; 658 struct ext4_extent tmp_dext, tmp_oext; 659 ext4_lblk_t orig_off = from, donor_off = from; 660 int depth; 661 int replaced_count = 0; 662 int dext_alen; 663 664 *err = ext4_es_remove_extent(orig_inode, from, count); 665 if (*err) 666 goto out; 667 668 *err = ext4_es_remove_extent(donor_inode, from, count); 669 if (*err) 670 goto out; 671 672 /* Get the original extent for the block "orig_off" */ 673 *err = get_ext_path(orig_inode, orig_off, &orig_path); 674 if (*err) 675 goto out; 676 677 /* Get the donor extent for the head */ 678 *err = get_ext_path(donor_inode, donor_off, &donor_path); 679 if (*err) 680 goto out; 681 depth = ext_depth(orig_inode); 682 oext = orig_path[depth].p_ext; 683 tmp_oext = *oext; 684 685 depth = ext_depth(donor_inode); 686 dext = donor_path[depth].p_ext; 687 if (unlikely(!dext)) 688 goto missing_donor_extent; 689 tmp_dext = *dext; 690 691 *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off, 692 donor_off, count); 693 if (*err) 694 goto out; 695 696 /* Loop for the donor extents */ 697 while (1) { 698 /* The extent for donor must be found. */ 699 if (unlikely(!dext)) { 700 missing_donor_extent: 701 EXT4_ERROR_INODE(donor_inode, 702 "The extent for donor must be found"); 703 *err = -EIO; 704 goto out; 705 } else if (donor_off != le32_to_cpu(tmp_dext.ee_block)) { 706 EXT4_ERROR_INODE(donor_inode, 707 "Donor offset(%u) and the first block of donor " 708 "extent(%u) should be equal", 709 donor_off, 710 le32_to_cpu(tmp_dext.ee_block)); 711 *err = -EIO; 712 goto out; 713 } 714 715 /* Set donor extent to orig extent */ 716 *err = mext_leaf_block(handle, orig_inode, 717 orig_path, &tmp_dext, &orig_off); 718 if (*err) 719 goto out; 720 721 /* Set orig extent to donor extent */ 722 *err = mext_leaf_block(handle, donor_inode, 723 donor_path, &tmp_oext, &donor_off); 724 if (*err) 725 goto out; 726 727 dext_alen = ext4_ext_get_actual_len(&tmp_dext); 728 replaced_count += dext_alen; 729 donor_off += dext_alen; 730 orig_off += dext_alen; 731 732 BUG_ON(replaced_count > count); 733 /* Already moved the expected blocks */ 734 if (replaced_count >= count) 735 break; 736 737 if (orig_path) 738 ext4_ext_drop_refs(orig_path); 739 *err = get_ext_path(orig_inode, orig_off, &orig_path); 740 if (*err) 741 goto out; 742 depth = ext_depth(orig_inode); 743 oext = orig_path[depth].p_ext; 744 tmp_oext = *oext; 745 746 if (donor_path) 747 ext4_ext_drop_refs(donor_path); 748 *err = get_ext_path(donor_inode, donor_off, &donor_path); 749 if (*err) 750 goto out; 751 depth = ext_depth(donor_inode); 752 dext = donor_path[depth].p_ext; 753 tmp_dext = *dext; 754 755 *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off, 756 donor_off, count - replaced_count); 757 if (*err) 758 goto out; 759 } 760 761 out: 762 if (orig_path) { 763 ext4_ext_drop_refs(orig_path); 764 kfree(orig_path); 765 } 766 if (donor_path) { 767 ext4_ext_drop_refs(donor_path); 768 kfree(donor_path); 769 } 770 771 return replaced_count; 772 } 773 774 /** 775 * mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2 776 * 777 * @inode1: the inode structure 778 * @inode2: the inode structure 779 * @index: page index 780 * @page: result page vector 781 * 782 * Grab two locked pages for inode's by inode order 783 */ 784 static int 785 mext_page_double_lock(struct inode *inode1, struct inode *inode2, 786 pgoff_t index, struct page *page[2]) 787 { 788 struct address_space *mapping[2]; 789 unsigned fl = AOP_FLAG_NOFS; 790 791 BUG_ON(!inode1 || !inode2); 792 if (inode1 < inode2) { 793 mapping[0] = inode1->i_mapping; 794 mapping[1] = inode2->i_mapping; 795 } else { 796 mapping[0] = inode2->i_mapping; 797 mapping[1] = inode1->i_mapping; 798 } 799 800 page[0] = grab_cache_page_write_begin(mapping[0], index, fl); 801 if (!page[0]) 802 return -ENOMEM; 803 804 page[1] = grab_cache_page_write_begin(mapping[1], index, fl); 805 if (!page[1]) { 806 unlock_page(page[0]); 807 page_cache_release(page[0]); 808 return -ENOMEM; 809 } 810 /* 811 * grab_cache_page_write_begin() may not wait on page's writeback if 812 * BDI not demand that. But it is reasonable to be very conservative 813 * here and explicitly wait on page's writeback 814 */ 815 wait_on_page_writeback(page[0]); 816 wait_on_page_writeback(page[1]); 817 if (inode1 > inode2) { 818 struct page *tmp; 819 tmp = page[0]; 820 page[0] = page[1]; 821 page[1] = tmp; 822 } 823 return 0; 824 } 825 826 /* Force page buffers uptodate w/o dropping page's lock */ 827 static int 828 mext_page_mkuptodate(struct page *page, unsigned from, unsigned to) 829 { 830 struct inode *inode = page->mapping->host; 831 sector_t block; 832 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; 833 unsigned int blocksize, block_start, block_end; 834 int i, err, nr = 0, partial = 0; 835 BUG_ON(!PageLocked(page)); 836 BUG_ON(PageWriteback(page)); 837 838 if (PageUptodate(page)) 839 return 0; 840 841 blocksize = 1 << inode->i_blkbits; 842 if (!page_has_buffers(page)) 843 create_empty_buffers(page, blocksize, 0); 844 845 head = page_buffers(page); 846 block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); 847 for (bh = head, block_start = 0; bh != head || !block_start; 848 block++, block_start = block_end, bh = bh->b_this_page) { 849 block_end = block_start + blocksize; 850 if (block_end <= from || block_start >= to) { 851 if (!buffer_uptodate(bh)) 852 partial = 1; 853 continue; 854 } 855 if (buffer_uptodate(bh)) 856 continue; 857 if (!buffer_mapped(bh)) { 858 err = ext4_get_block(inode, block, bh, 0); 859 if (err) { 860 SetPageError(page); 861 return err; 862 } 863 if (!buffer_mapped(bh)) { 864 zero_user(page, block_start, blocksize); 865 set_buffer_uptodate(bh); 866 continue; 867 } 868 } 869 BUG_ON(nr >= MAX_BUF_PER_PAGE); 870 arr[nr++] = bh; 871 } 872 /* No io required */ 873 if (!nr) 874 goto out; 875 876 for (i = 0; i < nr; i++) { 877 bh = arr[i]; 878 if (!bh_uptodate_or_lock(bh)) { 879 err = bh_submit_read(bh); 880 if (err) 881 return err; 882 } 883 } 884 out: 885 if (!partial) 886 SetPageUptodate(page); 887 return 0; 888 } 889 890 /** 891 * move_extent_per_page - Move extent data per page 892 * 893 * @o_filp: file structure of original file 894 * @donor_inode: donor inode 895 * @orig_page_offset: page index on original file 896 * @data_offset_in_page: block index where data swapping starts 897 * @block_len_in_page: the number of blocks to be swapped 898 * @unwritten: orig extent is unwritten or not 899 * @err: pointer to save return value 900 * 901 * Save the data in original inode blocks and replace original inode extents 902 * with donor inode extents by calling mext_replace_branches(). 903 * Finally, write out the saved data in new original inode blocks. Return 904 * replaced block count. 905 */ 906 static int 907 move_extent_per_page(struct file *o_filp, struct inode *donor_inode, 908 pgoff_t orig_page_offset, int data_offset_in_page, 909 int block_len_in_page, int unwritten, int *err) 910 { 911 struct inode *orig_inode = file_inode(o_filp); 912 struct page *pagep[2] = {NULL, NULL}; 913 handle_t *handle; 914 ext4_lblk_t orig_blk_offset; 915 unsigned long blocksize = orig_inode->i_sb->s_blocksize; 916 unsigned int w_flags = 0; 917 unsigned int tmp_data_size, data_size, replaced_size; 918 int err2, jblocks, retries = 0; 919 int replaced_count = 0; 920 int from = data_offset_in_page << orig_inode->i_blkbits; 921 int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits; 922 923 /* 924 * It needs twice the amount of ordinary journal buffers because 925 * inode and donor_inode may change each different metadata blocks. 926 */ 927 again: 928 *err = 0; 929 jblocks = ext4_writepage_trans_blocks(orig_inode) * 2; 930 handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks); 931 if (IS_ERR(handle)) { 932 *err = PTR_ERR(handle); 933 return 0; 934 } 935 936 if (segment_eq(get_fs(), KERNEL_DS)) 937 w_flags |= AOP_FLAG_UNINTERRUPTIBLE; 938 939 orig_blk_offset = orig_page_offset * blocks_per_page + 940 data_offset_in_page; 941 942 /* Calculate data_size */ 943 if ((orig_blk_offset + block_len_in_page - 1) == 944 ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) { 945 /* Replace the last block */ 946 tmp_data_size = orig_inode->i_size & (blocksize - 1); 947 /* 948 * If data_size equal zero, it shows data_size is multiples of 949 * blocksize. So we set appropriate value. 950 */ 951 if (tmp_data_size == 0) 952 tmp_data_size = blocksize; 953 954 data_size = tmp_data_size + 955 ((block_len_in_page - 1) << orig_inode->i_blkbits); 956 } else 957 data_size = block_len_in_page << orig_inode->i_blkbits; 958 959 replaced_size = data_size; 960 961 *err = mext_page_double_lock(orig_inode, donor_inode, orig_page_offset, 962 pagep); 963 if (unlikely(*err < 0)) 964 goto stop_journal; 965 /* 966 * If orig extent was unwritten it can become initialized 967 * at any time after i_data_sem was dropped, in order to 968 * serialize with delalloc we have recheck extent while we 969 * hold page's lock, if it is still the case data copy is not 970 * necessary, just swap data blocks between orig and donor. 971 */ 972 if (unwritten) { 973 ext4_double_down_write_data_sem(orig_inode, donor_inode); 974 /* If any of extents in range became initialized we have to 975 * fallback to data copying */ 976 unwritten = mext_check_coverage(orig_inode, orig_blk_offset, 977 block_len_in_page, 1, err); 978 if (*err) 979 goto drop_data_sem; 980 981 unwritten &= mext_check_coverage(donor_inode, orig_blk_offset, 982 block_len_in_page, 1, err); 983 if (*err) 984 goto drop_data_sem; 985 986 if (!unwritten) { 987 ext4_double_up_write_data_sem(orig_inode, donor_inode); 988 goto data_copy; 989 } 990 if ((page_has_private(pagep[0]) && 991 !try_to_release_page(pagep[0], 0)) || 992 (page_has_private(pagep[1]) && 993 !try_to_release_page(pagep[1], 0))) { 994 *err = -EBUSY; 995 goto drop_data_sem; 996 } 997 replaced_count = mext_replace_branches(handle, orig_inode, 998 donor_inode, orig_blk_offset, 999 block_len_in_page, err); 1000 drop_data_sem: 1001 ext4_double_up_write_data_sem(orig_inode, donor_inode); 1002 goto unlock_pages; 1003 } 1004 data_copy: 1005 *err = mext_page_mkuptodate(pagep[0], from, from + replaced_size); 1006 if (*err) 1007 goto unlock_pages; 1008 1009 /* At this point all buffers in range are uptodate, old mapping layout 1010 * is no longer required, try to drop it now. */ 1011 if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) || 1012 (page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) { 1013 *err = -EBUSY; 1014 goto unlock_pages; 1015 } 1016 ext4_double_down_write_data_sem(orig_inode, donor_inode); 1017 replaced_count = mext_replace_branches(handle, orig_inode, donor_inode, 1018 orig_blk_offset, 1019 block_len_in_page, err); 1020 ext4_double_up_write_data_sem(orig_inode, donor_inode); 1021 if (*err) { 1022 if (replaced_count) { 1023 block_len_in_page = replaced_count; 1024 replaced_size = 1025 block_len_in_page << orig_inode->i_blkbits; 1026 } else 1027 goto unlock_pages; 1028 } 1029 /* Perform all necessary steps similar write_begin()/write_end() 1030 * but keeping in mind that i_size will not change */ 1031 *err = __block_write_begin(pagep[0], from, replaced_size, 1032 ext4_get_block); 1033 if (!*err) 1034 *err = block_commit_write(pagep[0], from, from + replaced_size); 1035 1036 if (unlikely(*err < 0)) 1037 goto repair_branches; 1038 1039 /* Even in case of data=writeback it is reasonable to pin 1040 * inode to transaction, to prevent unexpected data loss */ 1041 *err = ext4_jbd2_file_inode(handle, orig_inode); 1042 1043 unlock_pages: 1044 unlock_page(pagep[0]); 1045 page_cache_release(pagep[0]); 1046 unlock_page(pagep[1]); 1047 page_cache_release(pagep[1]); 1048 stop_journal: 1049 ext4_journal_stop(handle); 1050 /* Buffer was busy because probably is pinned to journal transaction, 1051 * force transaction commit may help to free it. */ 1052 if (*err == -EBUSY && ext4_should_retry_alloc(orig_inode->i_sb, 1053 &retries)) 1054 goto again; 1055 return replaced_count; 1056 1057 repair_branches: 1058 /* 1059 * This should never ever happen! 1060 * Extents are swapped already, but we are not able to copy data. 1061 * Try to swap extents to it's original places 1062 */ 1063 ext4_double_down_write_data_sem(orig_inode, donor_inode); 1064 replaced_count = mext_replace_branches(handle, donor_inode, orig_inode, 1065 orig_blk_offset, 1066 block_len_in_page, &err2); 1067 ext4_double_up_write_data_sem(orig_inode, donor_inode); 1068 if (replaced_count != block_len_in_page) { 1069 EXT4_ERROR_INODE_BLOCK(orig_inode, (sector_t)(orig_blk_offset), 1070 "Unable to copy data block," 1071 " data will be lost."); 1072 *err = -EIO; 1073 } 1074 replaced_count = 0; 1075 goto unlock_pages; 1076 } 1077 1078 /** 1079 * mext_check_arguments - Check whether move extent can be done 1080 * 1081 * @orig_inode: original inode 1082 * @donor_inode: donor inode 1083 * @orig_start: logical start offset in block for orig 1084 * @donor_start: logical start offset in block for donor 1085 * @len: the number of blocks to be moved 1086 * 1087 * Check the arguments of ext4_move_extents() whether the files can be 1088 * exchanged with each other. 1089 * Return 0 on success, or a negative error value on failure. 1090 */ 1091 static int 1092 mext_check_arguments(struct inode *orig_inode, 1093 struct inode *donor_inode, __u64 orig_start, 1094 __u64 donor_start, __u64 *len) 1095 { 1096 ext4_lblk_t orig_blocks, donor_blocks; 1097 unsigned int blkbits = orig_inode->i_blkbits; 1098 unsigned int blocksize = 1 << blkbits; 1099 1100 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { 1101 ext4_debug("ext4 move extent: suid or sgid is set" 1102 " to donor file [ino:orig %lu, donor %lu]\n", 1103 orig_inode->i_ino, donor_inode->i_ino); 1104 return -EINVAL; 1105 } 1106 1107 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) 1108 return -EPERM; 1109 1110 /* Ext4 move extent does not support swapfile */ 1111 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { 1112 ext4_debug("ext4 move extent: The argument files should " 1113 "not be swapfile [ino:orig %lu, donor %lu]\n", 1114 orig_inode->i_ino, donor_inode->i_ino); 1115 return -EINVAL; 1116 } 1117 1118 /* Ext4 move extent supports only extent based file */ 1119 if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) { 1120 ext4_debug("ext4 move extent: orig file is not extents " 1121 "based file [ino:orig %lu]\n", orig_inode->i_ino); 1122 return -EOPNOTSUPP; 1123 } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) { 1124 ext4_debug("ext4 move extent: donor file is not extents " 1125 "based file [ino:donor %lu]\n", donor_inode->i_ino); 1126 return -EOPNOTSUPP; 1127 } 1128 1129 if ((!orig_inode->i_size) || (!donor_inode->i_size)) { 1130 ext4_debug("ext4 move extent: File size is 0 byte\n"); 1131 return -EINVAL; 1132 } 1133 1134 /* Start offset should be same */ 1135 if (orig_start != donor_start) { 1136 ext4_debug("ext4 move extent: orig and donor's start " 1137 "offset are not same [ino:orig %lu, donor %lu]\n", 1138 orig_inode->i_ino, donor_inode->i_ino); 1139 return -EINVAL; 1140 } 1141 1142 if ((orig_start >= EXT_MAX_BLOCKS) || 1143 (*len > EXT_MAX_BLOCKS) || 1144 (orig_start + *len >= EXT_MAX_BLOCKS)) { 1145 ext4_debug("ext4 move extent: Can't handle over [%u] blocks " 1146 "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS, 1147 orig_inode->i_ino, donor_inode->i_ino); 1148 return -EINVAL; 1149 } 1150 1151 if (orig_inode->i_size > donor_inode->i_size) { 1152 donor_blocks = (donor_inode->i_size + blocksize - 1) >> blkbits; 1153 /* TODO: eliminate this artificial restriction */ 1154 if (orig_start >= donor_blocks) { 1155 ext4_debug("ext4 move extent: orig start offset " 1156 "[%llu] should be less than donor file blocks " 1157 "[%u] [ino:orig %lu, donor %lu]\n", 1158 orig_start, donor_blocks, 1159 orig_inode->i_ino, donor_inode->i_ino); 1160 return -EINVAL; 1161 } 1162 1163 /* TODO: eliminate this artificial restriction */ 1164 if (orig_start + *len > donor_blocks) { 1165 ext4_debug("ext4 move extent: End offset [%llu] should " 1166 "be less than donor file blocks [%u]." 1167 "So adjust length from %llu to %llu " 1168 "[ino:orig %lu, donor %lu]\n", 1169 orig_start + *len, donor_blocks, 1170 *len, donor_blocks - orig_start, 1171 orig_inode->i_ino, donor_inode->i_ino); 1172 *len = donor_blocks - orig_start; 1173 } 1174 } else { 1175 orig_blocks = (orig_inode->i_size + blocksize - 1) >> blkbits; 1176 if (orig_start >= orig_blocks) { 1177 ext4_debug("ext4 move extent: start offset [%llu] " 1178 "should be less than original file blocks " 1179 "[%u] [ino:orig %lu, donor %lu]\n", 1180 orig_start, orig_blocks, 1181 orig_inode->i_ino, donor_inode->i_ino); 1182 return -EINVAL; 1183 } 1184 1185 if (orig_start + *len > orig_blocks) { 1186 ext4_debug("ext4 move extent: Adjust length " 1187 "from %llu to %llu. Because it should be " 1188 "less than original file blocks " 1189 "[ino:orig %lu, donor %lu]\n", 1190 *len, orig_blocks - orig_start, 1191 orig_inode->i_ino, donor_inode->i_ino); 1192 *len = orig_blocks - orig_start; 1193 } 1194 } 1195 1196 if (!*len) { 1197 ext4_debug("ext4 move extent: len should not be 0 " 1198 "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino, 1199 donor_inode->i_ino); 1200 return -EINVAL; 1201 } 1202 1203 return 0; 1204 } 1205 1206 /** 1207 * ext4_move_extents - Exchange the specified range of a file 1208 * 1209 * @o_filp: file structure of the original file 1210 * @d_filp: file structure of the donor file 1211 * @orig_start: start offset in block for orig 1212 * @donor_start: start offset in block for donor 1213 * @len: the number of blocks to be moved 1214 * @moved_len: moved block length 1215 * 1216 * This function returns 0 and moved block length is set in moved_len 1217 * if succeed, otherwise returns error value. 1218 * 1219 * Note: ext4_move_extents() proceeds the following order. 1220 * 1:ext4_move_extents() calculates the last block number of moving extent 1221 * function by the start block number (orig_start) and the number of blocks 1222 * to be moved (len) specified as arguments. 1223 * If the {orig, donor}_start points a hole, the extent's start offset 1224 * pointed by ext_cur (current extent), holecheck_path, orig_path are set 1225 * after hole behind. 1226 * 2:Continue step 3 to step 5, until the holecheck_path points to last_extent 1227 * or the ext_cur exceeds the block_end which is last logical block number. 1228 * 3:To get the length of continues area, call mext_next_extent() 1229 * specified with the ext_cur (initial value is holecheck_path) re-cursive, 1230 * until find un-continuous extent, the start logical block number exceeds 1231 * the block_end or the extent points to the last extent. 1232 * 4:Exchange the original inode data with donor inode data 1233 * from orig_page_offset to seq_end_page. 1234 * The start indexes of data are specified as arguments. 1235 * That of the original inode is orig_page_offset, 1236 * and the donor inode is also orig_page_offset 1237 * (To easily handle blocksize != pagesize case, the offset for the 1238 * donor inode is block unit). 1239 * 5:Update holecheck_path and orig_path to points a next proceeding extent, 1240 * then returns to step 2. 1241 * 6:Release holecheck_path, orig_path and set the len to moved_len 1242 * which shows the number of moved blocks. 1243 * The moved_len is useful for the command to calculate the file offset 1244 * for starting next move extent ioctl. 1245 * 7:Return 0 on success, or a negative error value on failure. 1246 */ 1247 int 1248 ext4_move_extents(struct file *o_filp, struct file *d_filp, 1249 __u64 orig_start, __u64 donor_start, __u64 len, 1250 __u64 *moved_len) 1251 { 1252 struct inode *orig_inode = file_inode(o_filp); 1253 struct inode *donor_inode = file_inode(d_filp); 1254 struct ext4_ext_path *orig_path = NULL, *holecheck_path = NULL; 1255 struct ext4_extent *ext_prev, *ext_cur, *ext_dummy; 1256 ext4_lblk_t block_start = orig_start; 1257 ext4_lblk_t block_end, seq_start, add_blocks, file_end, seq_blocks = 0; 1258 ext4_lblk_t rest_blocks; 1259 pgoff_t orig_page_offset = 0, seq_end_page; 1260 int ret, depth, last_extent = 0; 1261 int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits; 1262 int data_offset_in_page; 1263 int block_len_in_page; 1264 int unwritten; 1265 1266 if (orig_inode->i_sb != donor_inode->i_sb) { 1267 ext4_debug("ext4 move extent: The argument files " 1268 "should be in same FS [ino:orig %lu, donor %lu]\n", 1269 orig_inode->i_ino, donor_inode->i_ino); 1270 return -EINVAL; 1271 } 1272 1273 /* orig and donor should be different inodes */ 1274 if (orig_inode == donor_inode) { 1275 ext4_debug("ext4 move extent: The argument files should not " 1276 "be same inode [ino:orig %lu, donor %lu]\n", 1277 orig_inode->i_ino, donor_inode->i_ino); 1278 return -EINVAL; 1279 } 1280 1281 /* Regular file check */ 1282 if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) { 1283 ext4_debug("ext4 move extent: The argument files should be " 1284 "regular file [ino:orig %lu, donor %lu]\n", 1285 orig_inode->i_ino, donor_inode->i_ino); 1286 return -EINVAL; 1287 } 1288 /* TODO: This is non obvious task to swap blocks for inodes with full 1289 jornaling enabled */ 1290 if (ext4_should_journal_data(orig_inode) || 1291 ext4_should_journal_data(donor_inode)) { 1292 return -EINVAL; 1293 } 1294 /* Protect orig and donor inodes against a truncate */ 1295 lock_two_nondirectories(orig_inode, donor_inode); 1296 1297 /* Wait for all existing dio workers */ 1298 ext4_inode_block_unlocked_dio(orig_inode); 1299 ext4_inode_block_unlocked_dio(donor_inode); 1300 inode_dio_wait(orig_inode); 1301 inode_dio_wait(donor_inode); 1302 1303 /* Protect extent tree against block allocations via delalloc */ 1304 ext4_double_down_write_data_sem(orig_inode, donor_inode); 1305 /* Check the filesystem environment whether move_extent can be done */ 1306 ret = mext_check_arguments(orig_inode, donor_inode, orig_start, 1307 donor_start, &len); 1308 if (ret) 1309 goto out; 1310 1311 file_end = (i_size_read(orig_inode) - 1) >> orig_inode->i_blkbits; 1312 block_end = block_start + len - 1; 1313 if (file_end < block_end) 1314 len -= block_end - file_end; 1315 1316 ret = get_ext_path(orig_inode, block_start, &orig_path); 1317 if (ret) 1318 goto out; 1319 1320 /* Get path structure to check the hole */ 1321 ret = get_ext_path(orig_inode, block_start, &holecheck_path); 1322 if (ret) 1323 goto out; 1324 1325 depth = ext_depth(orig_inode); 1326 ext_cur = holecheck_path[depth].p_ext; 1327 1328 /* 1329 * Get proper starting location of block replacement if block_start was 1330 * within the hole. 1331 */ 1332 if (le32_to_cpu(ext_cur->ee_block) + 1333 ext4_ext_get_actual_len(ext_cur) - 1 < block_start) { 1334 /* 1335 * The hole exists between extents or the tail of 1336 * original file. 1337 */ 1338 last_extent = mext_next_extent(orig_inode, 1339 holecheck_path, &ext_cur); 1340 if (last_extent < 0) { 1341 ret = last_extent; 1342 goto out; 1343 } 1344 last_extent = mext_next_extent(orig_inode, orig_path, 1345 &ext_dummy); 1346 if (last_extent < 0) { 1347 ret = last_extent; 1348 goto out; 1349 } 1350 seq_start = le32_to_cpu(ext_cur->ee_block); 1351 } else if (le32_to_cpu(ext_cur->ee_block) > block_start) 1352 /* The hole exists at the beginning of original file. */ 1353 seq_start = le32_to_cpu(ext_cur->ee_block); 1354 else 1355 seq_start = block_start; 1356 1357 /* No blocks within the specified range. */ 1358 if (le32_to_cpu(ext_cur->ee_block) > block_end) { 1359 ext4_debug("ext4 move extent: The specified range of file " 1360 "may be the hole\n"); 1361 ret = -EINVAL; 1362 goto out; 1363 } 1364 1365 /* Adjust start blocks */ 1366 add_blocks = min(le32_to_cpu(ext_cur->ee_block) + 1367 ext4_ext_get_actual_len(ext_cur), block_end + 1) - 1368 max(le32_to_cpu(ext_cur->ee_block), block_start); 1369 1370 while (!last_extent && le32_to_cpu(ext_cur->ee_block) <= block_end) { 1371 seq_blocks += add_blocks; 1372 1373 /* Adjust tail blocks */ 1374 if (seq_start + seq_blocks - 1 > block_end) 1375 seq_blocks = block_end - seq_start + 1; 1376 1377 ext_prev = ext_cur; 1378 last_extent = mext_next_extent(orig_inode, holecheck_path, 1379 &ext_cur); 1380 if (last_extent < 0) { 1381 ret = last_extent; 1382 break; 1383 } 1384 add_blocks = ext4_ext_get_actual_len(ext_cur); 1385 1386 /* 1387 * Extend the length of contiguous block (seq_blocks) 1388 * if extents are contiguous. 1389 */ 1390 if (ext4_can_extents_be_merged(orig_inode, 1391 ext_prev, ext_cur) && 1392 block_end >= le32_to_cpu(ext_cur->ee_block) && 1393 !last_extent) 1394 continue; 1395 1396 /* Is original extent is unwritten */ 1397 unwritten = ext4_ext_is_unwritten(ext_prev); 1398 1399 data_offset_in_page = seq_start % blocks_per_page; 1400 1401 /* 1402 * Calculate data blocks count that should be swapped 1403 * at the first page. 1404 */ 1405 if (data_offset_in_page + seq_blocks > blocks_per_page) { 1406 /* Swapped blocks are across pages */ 1407 block_len_in_page = 1408 blocks_per_page - data_offset_in_page; 1409 } else { 1410 /* Swapped blocks are in a page */ 1411 block_len_in_page = seq_blocks; 1412 } 1413 1414 orig_page_offset = seq_start >> 1415 (PAGE_CACHE_SHIFT - orig_inode->i_blkbits); 1416 seq_end_page = (seq_start + seq_blocks - 1) >> 1417 (PAGE_CACHE_SHIFT - orig_inode->i_blkbits); 1418 seq_start = le32_to_cpu(ext_cur->ee_block); 1419 rest_blocks = seq_blocks; 1420 1421 /* 1422 * Up semaphore to avoid following problems: 1423 * a. transaction deadlock among ext4_journal_start, 1424 * ->write_begin via pagefault, and jbd2_journal_commit 1425 * b. racing with ->readpage, ->write_begin, and ext4_get_block 1426 * in move_extent_per_page 1427 */ 1428 ext4_double_up_write_data_sem(orig_inode, donor_inode); 1429 1430 while (orig_page_offset <= seq_end_page) { 1431 1432 /* Swap original branches with new branches */ 1433 block_len_in_page = move_extent_per_page( 1434 o_filp, donor_inode, 1435 orig_page_offset, 1436 data_offset_in_page, 1437 block_len_in_page, 1438 unwritten, &ret); 1439 1440 /* Count how many blocks we have exchanged */ 1441 *moved_len += block_len_in_page; 1442 if (ret < 0) 1443 break; 1444 if (*moved_len > len) { 1445 EXT4_ERROR_INODE(orig_inode, 1446 "We replaced blocks too much! " 1447 "sum of replaced: %llu requested: %llu", 1448 *moved_len, len); 1449 ret = -EIO; 1450 break; 1451 } 1452 1453 orig_page_offset++; 1454 data_offset_in_page = 0; 1455 rest_blocks -= block_len_in_page; 1456 if (rest_blocks > blocks_per_page) 1457 block_len_in_page = blocks_per_page; 1458 else 1459 block_len_in_page = rest_blocks; 1460 } 1461 1462 ext4_double_down_write_data_sem(orig_inode, donor_inode); 1463 if (ret < 0) 1464 break; 1465 1466 /* Decrease buffer counter */ 1467 if (holecheck_path) 1468 ext4_ext_drop_refs(holecheck_path); 1469 ret = get_ext_path(orig_inode, seq_start, &holecheck_path); 1470 if (ret) 1471 break; 1472 depth = holecheck_path->p_depth; 1473 1474 /* Decrease buffer counter */ 1475 if (orig_path) 1476 ext4_ext_drop_refs(orig_path); 1477 ret = get_ext_path(orig_inode, seq_start, &orig_path); 1478 if (ret) 1479 break; 1480 1481 ext_cur = holecheck_path[depth].p_ext; 1482 add_blocks = ext4_ext_get_actual_len(ext_cur); 1483 seq_blocks = 0; 1484 1485 } 1486 out: 1487 if (*moved_len) { 1488 ext4_discard_preallocations(orig_inode); 1489 ext4_discard_preallocations(donor_inode); 1490 } 1491 1492 if (orig_path) { 1493 ext4_ext_drop_refs(orig_path); 1494 kfree(orig_path); 1495 } 1496 if (holecheck_path) { 1497 ext4_ext_drop_refs(holecheck_path); 1498 kfree(holecheck_path); 1499 } 1500 ext4_double_up_write_data_sem(orig_inode, donor_inode); 1501 ext4_inode_resume_unlocked_dio(orig_inode); 1502 ext4_inode_resume_unlocked_dio(donor_inode); 1503 unlock_two_nondirectories(orig_inode, donor_inode); 1504 1505 return ret; 1506 } 1507