1 /* 2 * Copyright IBM Corporation, 2007 3 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of version 2.1 of the GNU Lesser General Public License 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 12 * 13 */ 14 15 #include <linux/module.h> 16 #include "ext4_jbd2.h" 17 #include "ext4_extents.h" 18 19 /* 20 * The contiguous blocks details which can be 21 * represented by a single extent 22 */ 23 struct list_blocks_struct { 24 ext4_lblk_t first_block, last_block; 25 ext4_fsblk_t first_pblock, last_pblock; 26 }; 27 28 static int finish_range(handle_t *handle, struct inode *inode, 29 struct list_blocks_struct *lb) 30 31 { 32 int retval = 0, needed; 33 struct ext4_extent newext; 34 struct ext4_ext_path *path; 35 if (lb->first_pblock == 0) 36 return 0; 37 38 /* Add the extent to temp inode*/ 39 newext.ee_block = cpu_to_le32(lb->first_block); 40 newext.ee_len = cpu_to_le16(lb->last_block - lb->first_block + 1); 41 ext4_ext_store_pblock(&newext, lb->first_pblock); 42 path = ext4_ext_find_extent(inode, lb->first_block, NULL); 43 44 if (IS_ERR(path)) { 45 retval = PTR_ERR(path); 46 path = NULL; 47 goto err_out; 48 } 49 50 /* 51 * Calculate the credit needed to inserting this extent 52 * Since we are doing this in loop we may accumalate extra 53 * credit. But below we try to not accumalate too much 54 * of them by restarting the journal. 55 */ 56 needed = ext4_ext_calc_credits_for_single_extent(inode, 57 lb->last_block - lb->first_block + 1, path); 58 59 /* 60 * Make sure the credit we accumalated is not really high 61 */ 62 if (needed && ext4_handle_has_enough_credits(handle, 63 EXT4_RESERVE_TRANS_BLOCKS)) { 64 retval = ext4_journal_restart(handle, needed); 65 if (retval) 66 goto err_out; 67 } else if (needed) { 68 retval = ext4_journal_extend(handle, needed); 69 if (retval) { 70 /* 71 * IF not able to extend the journal restart the journal 72 */ 73 retval = ext4_journal_restart(handle, needed); 74 if (retval) 75 goto err_out; 76 } 77 } 78 retval = ext4_ext_insert_extent(handle, inode, path, &newext); 79 err_out: 80 if (path) { 81 ext4_ext_drop_refs(path); 82 kfree(path); 83 } 84 lb->first_pblock = 0; 85 return retval; 86 } 87 88 static int update_extent_range(handle_t *handle, struct inode *inode, 89 ext4_fsblk_t pblock, ext4_lblk_t blk_num, 90 struct list_blocks_struct *lb) 91 { 92 int retval; 93 /* 94 * See if we can add on to the existing range (if it exists) 95 */ 96 if (lb->first_pblock && 97 (lb->last_pblock+1 == pblock) && 98 (lb->last_block+1 == blk_num)) { 99 lb->last_pblock = pblock; 100 lb->last_block = blk_num; 101 return 0; 102 } 103 /* 104 * Start a new range. 105 */ 106 retval = finish_range(handle, inode, lb); 107 lb->first_pblock = lb->last_pblock = pblock; 108 lb->first_block = lb->last_block = blk_num; 109 110 return retval; 111 } 112 113 static int update_ind_extent_range(handle_t *handle, struct inode *inode, 114 ext4_fsblk_t pblock, ext4_lblk_t *blk_nump, 115 struct list_blocks_struct *lb) 116 { 117 struct buffer_head *bh; 118 __le32 *i_data; 119 int i, retval = 0; 120 ext4_lblk_t blk_count = *blk_nump; 121 unsigned long max_entries = inode->i_sb->s_blocksize >> 2; 122 123 if (!pblock) { 124 /* Only update the file block number */ 125 *blk_nump += max_entries; 126 return 0; 127 } 128 129 bh = sb_bread(inode->i_sb, pblock); 130 if (!bh) 131 return -EIO; 132 133 i_data = (__le32 *)bh->b_data; 134 for (i = 0; i < max_entries; i++, blk_count++) { 135 if (i_data[i]) { 136 retval = update_extent_range(handle, inode, 137 le32_to_cpu(i_data[i]), 138 blk_count, lb); 139 if (retval) 140 break; 141 } 142 } 143 144 /* Update the file block number */ 145 *blk_nump = blk_count; 146 put_bh(bh); 147 return retval; 148 149 } 150 151 static int update_dind_extent_range(handle_t *handle, struct inode *inode, 152 ext4_fsblk_t pblock, ext4_lblk_t *blk_nump, 153 struct list_blocks_struct *lb) 154 { 155 struct buffer_head *bh; 156 __le32 *i_data; 157 int i, retval = 0; 158 ext4_lblk_t blk_count = *blk_nump; 159 unsigned long max_entries = inode->i_sb->s_blocksize >> 2; 160 161 if (!pblock) { 162 /* Only update the file block number */ 163 *blk_nump += max_entries * max_entries; 164 return 0; 165 } 166 bh = sb_bread(inode->i_sb, pblock); 167 if (!bh) 168 return -EIO; 169 170 i_data = (__le32 *)bh->b_data; 171 for (i = 0; i < max_entries; i++) { 172 if (i_data[i]) { 173 retval = update_ind_extent_range(handle, inode, 174 le32_to_cpu(i_data[i]), 175 &blk_count, lb); 176 if (retval) 177 break; 178 } else { 179 /* Only update the file block number */ 180 blk_count += max_entries; 181 } 182 } 183 184 /* Update the file block number */ 185 *blk_nump = blk_count; 186 put_bh(bh); 187 return retval; 188 189 } 190 191 static int update_tind_extent_range(handle_t *handle, struct inode *inode, 192 ext4_fsblk_t pblock, ext4_lblk_t *blk_nump, 193 struct list_blocks_struct *lb) 194 { 195 struct buffer_head *bh; 196 __le32 *i_data; 197 int i, retval = 0; 198 ext4_lblk_t blk_count = *blk_nump; 199 unsigned long max_entries = inode->i_sb->s_blocksize >> 2; 200 201 if (!pblock) { 202 /* Only update the file block number */ 203 *blk_nump += max_entries * max_entries * max_entries; 204 return 0; 205 } 206 bh = sb_bread(inode->i_sb, pblock); 207 if (!bh) 208 return -EIO; 209 210 i_data = (__le32 *)bh->b_data; 211 for (i = 0; i < max_entries; i++) { 212 if (i_data[i]) { 213 retval = update_dind_extent_range(handle, inode, 214 le32_to_cpu(i_data[i]), 215 &blk_count, lb); 216 if (retval) 217 break; 218 } else 219 /* Only update the file block number */ 220 blk_count += max_entries * max_entries; 221 } 222 /* Update the file block number */ 223 *blk_nump = blk_count; 224 put_bh(bh); 225 return retval; 226 227 } 228 229 static int extend_credit_for_blkdel(handle_t *handle, struct inode *inode) 230 { 231 int retval = 0, needed; 232 233 if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1)) 234 return 0; 235 /* 236 * We are freeing a blocks. During this we touch 237 * superblock, group descriptor and block bitmap. 238 * So allocate a credit of 3. We may update 239 * quota (user and group). 240 */ 241 needed = 3 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); 242 243 if (ext4_journal_extend(handle, needed) != 0) 244 retval = ext4_journal_restart(handle, needed); 245 246 return retval; 247 } 248 249 static int free_dind_blocks(handle_t *handle, 250 struct inode *inode, __le32 i_data) 251 { 252 int i; 253 __le32 *tmp_idata; 254 struct buffer_head *bh; 255 unsigned long max_entries = inode->i_sb->s_blocksize >> 2; 256 257 bh = sb_bread(inode->i_sb, le32_to_cpu(i_data)); 258 if (!bh) 259 return -EIO; 260 261 tmp_idata = (__le32 *)bh->b_data; 262 for (i = 0; i < max_entries; i++) { 263 if (tmp_idata[i]) { 264 extend_credit_for_blkdel(handle, inode); 265 ext4_free_blocks(handle, inode, 266 le32_to_cpu(tmp_idata[i]), 1, 1); 267 } 268 } 269 put_bh(bh); 270 extend_credit_for_blkdel(handle, inode); 271 ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1); 272 return 0; 273 } 274 275 static int free_tind_blocks(handle_t *handle, 276 struct inode *inode, __le32 i_data) 277 { 278 int i, retval = 0; 279 __le32 *tmp_idata; 280 struct buffer_head *bh; 281 unsigned long max_entries = inode->i_sb->s_blocksize >> 2; 282 283 bh = sb_bread(inode->i_sb, le32_to_cpu(i_data)); 284 if (!bh) 285 return -EIO; 286 287 tmp_idata = (__le32 *)bh->b_data; 288 for (i = 0; i < max_entries; i++) { 289 if (tmp_idata[i]) { 290 retval = free_dind_blocks(handle, 291 inode, tmp_idata[i]); 292 if (retval) { 293 put_bh(bh); 294 return retval; 295 } 296 } 297 } 298 put_bh(bh); 299 extend_credit_for_blkdel(handle, inode); 300 ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1); 301 return 0; 302 } 303 304 static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data) 305 { 306 int retval; 307 308 /* ei->i_data[EXT4_IND_BLOCK] */ 309 if (i_data[0]) { 310 extend_credit_for_blkdel(handle, inode); 311 ext4_free_blocks(handle, inode, 312 le32_to_cpu(i_data[0]), 1, 1); 313 } 314 315 /* ei->i_data[EXT4_DIND_BLOCK] */ 316 if (i_data[1]) { 317 retval = free_dind_blocks(handle, inode, i_data[1]); 318 if (retval) 319 return retval; 320 } 321 322 /* ei->i_data[EXT4_TIND_BLOCK] */ 323 if (i_data[2]) { 324 retval = free_tind_blocks(handle, inode, i_data[2]); 325 if (retval) 326 return retval; 327 } 328 return 0; 329 } 330 331 static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode, 332 struct inode *tmp_inode) 333 { 334 int retval; 335 __le32 i_data[3]; 336 struct ext4_inode_info *ei = EXT4_I(inode); 337 struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode); 338 339 /* 340 * One credit accounted for writing the 341 * i_data field of the original inode 342 */ 343 retval = ext4_journal_extend(handle, 1); 344 if (retval) { 345 retval = ext4_journal_restart(handle, 1); 346 if (retval) 347 goto err_out; 348 } 349 350 i_data[0] = ei->i_data[EXT4_IND_BLOCK]; 351 i_data[1] = ei->i_data[EXT4_DIND_BLOCK]; 352 i_data[2] = ei->i_data[EXT4_TIND_BLOCK]; 353 354 down_write(&EXT4_I(inode)->i_data_sem); 355 /* 356 * if EXT4_EXT_MIGRATE is cleared a block allocation 357 * happened after we started the migrate. We need to 358 * fail the migrate 359 */ 360 if (!(EXT4_I(inode)->i_flags & EXT4_EXT_MIGRATE)) { 361 retval = -EAGAIN; 362 up_write(&EXT4_I(inode)->i_data_sem); 363 goto err_out; 364 } else 365 EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags & 366 ~EXT4_EXT_MIGRATE; 367 /* 368 * We have the extent map build with the tmp inode. 369 * Now copy the i_data across 370 */ 371 ei->i_flags |= EXT4_EXTENTS_FL; 372 memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data)); 373 374 /* 375 * Update i_blocks with the new blocks that got 376 * allocated while adding extents for extent index 377 * blocks. 378 * 379 * While converting to extents we need not 380 * update the orignal inode i_blocks for extent blocks 381 * via quota APIs. The quota update happened via tmp_inode already. 382 */ 383 spin_lock(&inode->i_lock); 384 inode->i_blocks += tmp_inode->i_blocks; 385 spin_unlock(&inode->i_lock); 386 up_write(&EXT4_I(inode)->i_data_sem); 387 388 /* 389 * We mark the inode dirty after, because we decrement the 390 * i_blocks when freeing the indirect meta-data blocks 391 */ 392 retval = free_ind_block(handle, inode, i_data); 393 ext4_mark_inode_dirty(handle, inode); 394 395 err_out: 396 return retval; 397 } 398 399 static int free_ext_idx(handle_t *handle, struct inode *inode, 400 struct ext4_extent_idx *ix) 401 { 402 int i, retval = 0; 403 ext4_fsblk_t block; 404 struct buffer_head *bh; 405 struct ext4_extent_header *eh; 406 407 block = idx_pblock(ix); 408 bh = sb_bread(inode->i_sb, block); 409 if (!bh) 410 return -EIO; 411 412 eh = (struct ext4_extent_header *)bh->b_data; 413 if (eh->eh_depth != 0) { 414 ix = EXT_FIRST_INDEX(eh); 415 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) { 416 retval = free_ext_idx(handle, inode, ix); 417 if (retval) 418 break; 419 } 420 } 421 put_bh(bh); 422 extend_credit_for_blkdel(handle, inode); 423 ext4_free_blocks(handle, inode, block, 1, 1); 424 return retval; 425 } 426 427 /* 428 * Free the extent meta data blocks only 429 */ 430 static int free_ext_block(handle_t *handle, struct inode *inode) 431 { 432 int i, retval = 0; 433 struct ext4_inode_info *ei = EXT4_I(inode); 434 struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data; 435 struct ext4_extent_idx *ix; 436 if (eh->eh_depth == 0) 437 /* 438 * No extra blocks allocated for extent meta data 439 */ 440 return 0; 441 ix = EXT_FIRST_INDEX(eh); 442 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) { 443 retval = free_ext_idx(handle, inode, ix); 444 if (retval) 445 return retval; 446 } 447 return retval; 448 449 } 450 451 int ext4_ext_migrate(struct inode *inode) 452 { 453 handle_t *handle; 454 int retval = 0, i; 455 __le32 *i_data; 456 ext4_lblk_t blk_count = 0; 457 struct ext4_inode_info *ei; 458 struct inode *tmp_inode = NULL; 459 struct list_blocks_struct lb; 460 unsigned long max_entries; 461 __u32 goal; 462 463 /* 464 * If the filesystem does not support extents, or the inode 465 * already is extent-based, error out. 466 */ 467 if (!EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb, 468 EXT4_FEATURE_INCOMPAT_EXTENTS) || 469 (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 470 return -EINVAL; 471 472 if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0) 473 /* 474 * don't migrate fast symlink 475 */ 476 return retval; 477 478 handle = ext4_journal_start(inode, 479 EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 480 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 + 481 2 * EXT4_QUOTA_INIT_BLOCKS(inode->i_sb) 482 + 1); 483 if (IS_ERR(handle)) { 484 retval = PTR_ERR(handle); 485 return retval; 486 } 487 goal = (((inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb)) * 488 EXT4_INODES_PER_GROUP(inode->i_sb)) + 1; 489 tmp_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode, 490 S_IFREG, 0, goal); 491 if (IS_ERR(tmp_inode)) { 492 retval = -ENOMEM; 493 ext4_journal_stop(handle); 494 return retval; 495 } 496 i_size_write(tmp_inode, i_size_read(inode)); 497 /* 498 * We don't want the inode to be reclaimed 499 * if we got interrupted in between. We have 500 * this tmp inode carrying reference to the 501 * data blocks of the original file. We set 502 * the i_nlink to zero at the last stage after 503 * switching the original file to extent format 504 */ 505 tmp_inode->i_nlink = 1; 506 507 ext4_ext_tree_init(handle, tmp_inode); 508 ext4_orphan_add(handle, tmp_inode); 509 ext4_journal_stop(handle); 510 511 /* 512 * start with one credit accounted for 513 * superblock modification. 514 * 515 * For the tmp_inode we already have commited the 516 * trascation that created the inode. Later as and 517 * when we add extents we extent the journal 518 */ 519 /* 520 * Even though we take i_mutex we can still cause block allocation 521 * via mmap write to holes. If we have allocated new blocks we fail 522 * migrate. New block allocation will clear EXT4_EXT_MIGRATE flag. 523 * The flag is updated with i_data_sem held to prevent racing with 524 * block allocation. 525 */ 526 down_read((&EXT4_I(inode)->i_data_sem)); 527 EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags | EXT4_EXT_MIGRATE; 528 up_read((&EXT4_I(inode)->i_data_sem)); 529 530 handle = ext4_journal_start(inode, 1); 531 532 ei = EXT4_I(inode); 533 i_data = ei->i_data; 534 memset(&lb, 0, sizeof(lb)); 535 536 /* 32 bit block address 4 bytes */ 537 max_entries = inode->i_sb->s_blocksize >> 2; 538 for (i = 0; i < EXT4_NDIR_BLOCKS; i++, blk_count++) { 539 if (i_data[i]) { 540 retval = update_extent_range(handle, tmp_inode, 541 le32_to_cpu(i_data[i]), 542 blk_count, &lb); 543 if (retval) 544 goto err_out; 545 } 546 } 547 if (i_data[EXT4_IND_BLOCK]) { 548 retval = update_ind_extent_range(handle, tmp_inode, 549 le32_to_cpu(i_data[EXT4_IND_BLOCK]), 550 &blk_count, &lb); 551 if (retval) 552 goto err_out; 553 } else 554 blk_count += max_entries; 555 if (i_data[EXT4_DIND_BLOCK]) { 556 retval = update_dind_extent_range(handle, tmp_inode, 557 le32_to_cpu(i_data[EXT4_DIND_BLOCK]), 558 &blk_count, &lb); 559 if (retval) 560 goto err_out; 561 } else 562 blk_count += max_entries * max_entries; 563 if (i_data[EXT4_TIND_BLOCK]) { 564 retval = update_tind_extent_range(handle, tmp_inode, 565 le32_to_cpu(i_data[EXT4_TIND_BLOCK]), 566 &blk_count, &lb); 567 if (retval) 568 goto err_out; 569 } 570 /* 571 * Build the last extent 572 */ 573 retval = finish_range(handle, tmp_inode, &lb); 574 err_out: 575 if (retval) 576 /* 577 * Failure case delete the extent information with the 578 * tmp_inode 579 */ 580 free_ext_block(handle, tmp_inode); 581 else { 582 retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode); 583 if (retval) 584 /* 585 * if we fail to swap inode data free the extent 586 * details of the tmp inode 587 */ 588 free_ext_block(handle, tmp_inode); 589 } 590 591 /* We mark the tmp_inode dirty via ext4_ext_tree_init. */ 592 if (ext4_journal_extend(handle, 1) != 0) 593 ext4_journal_restart(handle, 1); 594 595 /* 596 * Mark the tmp_inode as of size zero 597 */ 598 i_size_write(tmp_inode, 0); 599 600 /* 601 * set the i_blocks count to zero 602 * so that the ext4_delete_inode does the 603 * right job 604 * 605 * We don't need to take the i_lock because 606 * the inode is not visible to user space. 607 */ 608 tmp_inode->i_blocks = 0; 609 610 /* Reset the extent details */ 611 ext4_ext_tree_init(handle, tmp_inode); 612 613 /* 614 * Set the i_nlink to zero so that 615 * generic_drop_inode really deletes the 616 * inode 617 */ 618 tmp_inode->i_nlink = 0; 619 620 ext4_journal_stop(handle); 621 622 iput(tmp_inode); 623 624 return retval; 625 } 626