1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/ext4/balloc.c 4 * 5 * Copyright (C) 1992, 1993, 1994, 1995 6 * Remy Card (card@masi.ibp.fr) 7 * Laboratoire MASI - Institut Blaise Pascal 8 * Universite Pierre et Marie Curie (Paris VI) 9 * 10 * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993 11 * Big-endian to little-endian byte-swapping/bitmaps by 12 * David S. Miller (davem@caip.rutgers.edu), 1995 13 */ 14 15 #include <linux/time.h> 16 #include <linux/capability.h> 17 #include <linux/fs.h> 18 #include <linux/quotaops.h> 19 #include <linux/buffer_head.h> 20 #include "ext4.h" 21 #include "ext4_jbd2.h" 22 #include "mballoc.h" 23 24 #include <trace/events/ext4.h> 25 26 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 27 ext4_group_t block_group); 28 /* 29 * balloc.c contains the blocks allocation and deallocation routines 30 */ 31 32 /* 33 * Calculate block group number for a given block number 34 */ 35 ext4_group_t ext4_get_group_number(struct super_block *sb, 36 ext4_fsblk_t block) 37 { 38 ext4_group_t group; 39 40 if (test_opt2(sb, STD_GROUP_SIZE)) 41 group = (block - 42 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >> 43 (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3); 44 else 45 ext4_get_group_no_and_offset(sb, block, &group, NULL); 46 return group; 47 } 48 49 /* 50 * Calculate the block group number and offset into the block/cluster 51 * allocation bitmap, given a block number 52 */ 53 void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, 54 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) 55 { 56 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 57 ext4_grpblk_t offset; 58 59 blocknr = blocknr - le32_to_cpu(es->s_first_data_block); 60 offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> 61 EXT4_SB(sb)->s_cluster_bits; 62 if (offsetp) 63 *offsetp = offset; 64 if (blockgrpp) 65 *blockgrpp = blocknr; 66 67 } 68 69 /* 70 * Check whether the 'block' lives within the 'block_group'. Returns 1 if so 71 * and 0 otherwise. 72 */ 73 static inline int ext4_block_in_group(struct super_block *sb, 74 ext4_fsblk_t block, 75 ext4_group_t block_group) 76 { 77 ext4_group_t actual_group; 78 79 actual_group = ext4_get_group_number(sb, block); 80 return (actual_group == block_group) ? 1 : 0; 81 } 82 83 /* Return the number of clusters used for file system metadata; this 84 * represents the overhead needed by the file system. 85 */ 86 static unsigned ext4_num_overhead_clusters(struct super_block *sb, 87 ext4_group_t block_group, 88 struct ext4_group_desc *gdp) 89 { 90 unsigned num_clusters; 91 int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c; 92 ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); 93 ext4_fsblk_t itbl_blk; 94 struct ext4_sb_info *sbi = EXT4_SB(sb); 95 96 /* This is the number of clusters used by the superblock, 97 * block group descriptors, and reserved block group 98 * descriptor blocks */ 99 num_clusters = ext4_num_base_meta_clusters(sb, block_group); 100 101 /* 102 * For the allocation bitmaps and inode table, we first need 103 * to check to see if the block is in the block group. If it 104 * is, then check to see if the cluster is already accounted 105 * for in the clusters used for the base metadata cluster, or 106 * if we can increment the base metadata cluster to include 107 * that block. Otherwise, we will have to track the cluster 108 * used for the allocation bitmap or inode table explicitly. 109 * Normally all of these blocks are contiguous, so the special 110 * case handling shouldn't be necessary except for *very* 111 * unusual file system layouts. 112 */ 113 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { 114 block_cluster = EXT4_B2C(sbi, 115 ext4_block_bitmap(sb, gdp) - start); 116 if (block_cluster < num_clusters) 117 block_cluster = -1; 118 else if (block_cluster == num_clusters) { 119 num_clusters++; 120 block_cluster = -1; 121 } 122 } 123 124 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { 125 inode_cluster = EXT4_B2C(sbi, 126 ext4_inode_bitmap(sb, gdp) - start); 127 if (inode_cluster < num_clusters) 128 inode_cluster = -1; 129 else if (inode_cluster == num_clusters) { 130 num_clusters++; 131 inode_cluster = -1; 132 } 133 } 134 135 itbl_blk = ext4_inode_table(sb, gdp); 136 for (i = 0; i < sbi->s_itb_per_group; i++) { 137 if (ext4_block_in_group(sb, itbl_blk + i, block_group)) { 138 c = EXT4_B2C(sbi, itbl_blk + i - start); 139 if ((c < num_clusters) || (c == inode_cluster) || 140 (c == block_cluster) || (c == itbl_cluster)) 141 continue; 142 if (c == num_clusters) { 143 num_clusters++; 144 continue; 145 } 146 num_clusters++; 147 itbl_cluster = c; 148 } 149 } 150 151 if (block_cluster != -1) 152 num_clusters++; 153 if (inode_cluster != -1) 154 num_clusters++; 155 156 return num_clusters; 157 } 158 159 static unsigned int num_clusters_in_group(struct super_block *sb, 160 ext4_group_t block_group) 161 { 162 unsigned int blocks; 163 164 if (block_group == ext4_get_groups_count(sb) - 1) { 165 /* 166 * Even though mke2fs always initializes the first and 167 * last group, just in case some other tool was used, 168 * we need to make sure we calculate the right free 169 * blocks. 170 */ 171 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - 172 ext4_group_first_block_no(sb, block_group); 173 } else 174 blocks = EXT4_BLOCKS_PER_GROUP(sb); 175 return EXT4_NUM_B2C(EXT4_SB(sb), blocks); 176 } 177 178 /* Initializes an uninitialized block bitmap */ 179 static int ext4_init_block_bitmap(struct super_block *sb, 180 struct buffer_head *bh, 181 ext4_group_t block_group, 182 struct ext4_group_desc *gdp) 183 { 184 unsigned int bit, bit_max; 185 struct ext4_sb_info *sbi = EXT4_SB(sb); 186 ext4_fsblk_t start, tmp; 187 int flex_bg = 0; 188 189 J_ASSERT_BH(bh, buffer_locked(bh)); 190 191 /* If checksum is bad mark all blocks used to prevent allocation 192 * essentially implementing a per-group read-only flag. */ 193 if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) { 194 ext4_mark_group_bitmap_corrupted(sb, block_group, 195 EXT4_GROUP_INFO_BBITMAP_CORRUPT | 196 EXT4_GROUP_INFO_IBITMAP_CORRUPT); 197 return -EFSBADCRC; 198 } 199 memset(bh->b_data, 0, sb->s_blocksize); 200 201 bit_max = ext4_num_base_meta_clusters(sb, block_group); 202 if ((bit_max >> 3) >= bh->b_size) 203 return -EFSCORRUPTED; 204 205 for (bit = 0; bit < bit_max; bit++) 206 ext4_set_bit(bit, bh->b_data); 207 208 start = ext4_group_first_block_no(sb, block_group); 209 210 if (ext4_has_feature_flex_bg(sb)) 211 flex_bg = 1; 212 213 /* Set bits for block and inode bitmaps, and inode table */ 214 tmp = ext4_block_bitmap(sb, gdp); 215 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 216 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 217 218 tmp = ext4_inode_bitmap(sb, gdp); 219 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 220 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 221 222 tmp = ext4_inode_table(sb, gdp); 223 for (; tmp < ext4_inode_table(sb, gdp) + 224 sbi->s_itb_per_group; tmp++) { 225 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 226 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 227 } 228 229 /* 230 * Also if the number of blocks within the group is less than 231 * the blocksize * 8 ( which is the size of bitmap ), set rest 232 * of the block bitmap to 1 233 */ 234 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), 235 sb->s_blocksize * 8, bh->b_data); 236 return 0; 237 } 238 239 /* Return the number of free blocks in a block group. It is used when 240 * the block bitmap is uninitialized, so we can't just count the bits 241 * in the bitmap. */ 242 unsigned ext4_free_clusters_after_init(struct super_block *sb, 243 ext4_group_t block_group, 244 struct ext4_group_desc *gdp) 245 { 246 return num_clusters_in_group(sb, block_group) - 247 ext4_num_overhead_clusters(sb, block_group, gdp); 248 } 249 250 /* 251 * The free blocks are managed by bitmaps. A file system contains several 252 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 253 * block for inodes, N blocks for the inode table and data blocks. 254 * 255 * The file system contains group descriptors which are located after the 256 * super block. Each descriptor contains the number of the bitmap block and 257 * the free blocks count in the block. The descriptors are loaded in memory 258 * when a file system is mounted (see ext4_fill_super). 259 */ 260 261 /** 262 * ext4_get_group_desc() -- load group descriptor from disk 263 * @sb: super block 264 * @block_group: given block group 265 * @bh: pointer to the buffer head to store the block 266 * group descriptor 267 */ 268 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, 269 ext4_group_t block_group, 270 struct buffer_head **bh) 271 { 272 unsigned int group_desc; 273 unsigned int offset; 274 ext4_group_t ngroups = ext4_get_groups_count(sb); 275 struct ext4_group_desc *desc; 276 struct ext4_sb_info *sbi = EXT4_SB(sb); 277 278 if (block_group >= ngroups) { 279 ext4_error(sb, "block_group >= groups_count - block_group = %u," 280 " groups_count = %u", block_group, ngroups); 281 282 return NULL; 283 } 284 285 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 286 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 287 if (!sbi->s_group_desc[group_desc]) { 288 ext4_error(sb, "Group descriptor not loaded - " 289 "block_group = %u, group_desc = %u, desc = %u", 290 block_group, group_desc, offset); 291 return NULL; 292 } 293 294 desc = (struct ext4_group_desc *)( 295 (__u8 *)sbi->s_group_desc[group_desc]->b_data + 296 offset * EXT4_DESC_SIZE(sb)); 297 if (bh) 298 *bh = sbi->s_group_desc[group_desc]; 299 return desc; 300 } 301 302 /* 303 * Return the block number which was discovered to be invalid, or 0 if 304 * the block bitmap is valid. 305 */ 306 static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, 307 struct ext4_group_desc *desc, 308 ext4_group_t block_group, 309 struct buffer_head *bh) 310 { 311 struct ext4_sb_info *sbi = EXT4_SB(sb); 312 ext4_grpblk_t offset; 313 ext4_grpblk_t next_zero_bit; 314 ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); 315 ext4_fsblk_t blk; 316 ext4_fsblk_t group_first_block; 317 318 if (ext4_has_feature_flex_bg(sb)) { 319 /* with FLEX_BG, the inode/block bitmaps and itable 320 * blocks may not be in the group at all 321 * so the bitmap validation will be skipped for those groups 322 * or it has to also read the block group where the bitmaps 323 * are located to verify they are set. 324 */ 325 return 0; 326 } 327 group_first_block = ext4_group_first_block_no(sb, block_group); 328 329 /* check whether block bitmap block number is set */ 330 blk = ext4_block_bitmap(sb, desc); 331 offset = blk - group_first_block; 332 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 333 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 334 /* bad block bitmap */ 335 return blk; 336 337 /* check whether the inode bitmap block number is set */ 338 blk = ext4_inode_bitmap(sb, desc); 339 offset = blk - group_first_block; 340 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 341 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 342 /* bad block bitmap */ 343 return blk; 344 345 /* check whether the inode table block number is set */ 346 blk = ext4_inode_table(sb, desc); 347 offset = blk - group_first_block; 348 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 349 EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit) 350 return blk; 351 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 352 EXT4_B2C(sbi, offset + sbi->s_itb_per_group), 353 EXT4_B2C(sbi, offset)); 354 if (next_zero_bit < 355 EXT4_B2C(sbi, offset + sbi->s_itb_per_group)) 356 /* bad bitmap for inode tables */ 357 return blk; 358 return 0; 359 } 360 361 static int ext4_validate_block_bitmap(struct super_block *sb, 362 struct ext4_group_desc *desc, 363 ext4_group_t block_group, 364 struct buffer_head *bh) 365 { 366 ext4_fsblk_t blk; 367 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); 368 369 if (buffer_verified(bh)) 370 return 0; 371 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 372 return -EFSCORRUPTED; 373 374 ext4_lock_group(sb, block_group); 375 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, 376 desc, bh))) { 377 ext4_unlock_group(sb, block_group); 378 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 379 ext4_mark_group_bitmap_corrupted(sb, block_group, 380 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 381 return -EFSBADCRC; 382 } 383 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 384 if (unlikely(blk != 0)) { 385 ext4_unlock_group(sb, block_group); 386 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 387 block_group, blk); 388 ext4_mark_group_bitmap_corrupted(sb, block_group, 389 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 390 return -EFSCORRUPTED; 391 } 392 set_buffer_verified(bh); 393 ext4_unlock_group(sb, block_group); 394 return 0; 395 } 396 397 /** 398 * ext4_read_block_bitmap_nowait() 399 * @sb: super block 400 * @block_group: given block group 401 * 402 * Read the bitmap for a given block_group,and validate the 403 * bits for block/inode/inode tables are set in the bitmaps 404 * 405 * Return buffer_head on success or NULL in case of failure. 406 */ 407 struct buffer_head * 408 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) 409 { 410 struct ext4_group_desc *desc; 411 struct ext4_sb_info *sbi = EXT4_SB(sb); 412 struct buffer_head *bh; 413 ext4_fsblk_t bitmap_blk; 414 int err; 415 416 desc = ext4_get_group_desc(sb, block_group, NULL); 417 if (!desc) 418 return ERR_PTR(-EFSCORRUPTED); 419 bitmap_blk = ext4_block_bitmap(sb, desc); 420 if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || 421 (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { 422 ext4_error(sb, "Invalid block bitmap block %llu in " 423 "block_group %u", bitmap_blk, block_group); 424 ext4_mark_group_bitmap_corrupted(sb, block_group, 425 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 426 return ERR_PTR(-EFSCORRUPTED); 427 } 428 bh = sb_getblk(sb, bitmap_blk); 429 if (unlikely(!bh)) { 430 ext4_error(sb, "Cannot get buffer for block bitmap - " 431 "block_group = %u, block_bitmap = %llu", 432 block_group, bitmap_blk); 433 return ERR_PTR(-ENOMEM); 434 } 435 436 if (bitmap_uptodate(bh)) 437 goto verify; 438 439 lock_buffer(bh); 440 if (bitmap_uptodate(bh)) { 441 unlock_buffer(bh); 442 goto verify; 443 } 444 ext4_lock_group(sb, block_group); 445 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 446 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 447 set_bitmap_uptodate(bh); 448 set_buffer_uptodate(bh); 449 set_buffer_verified(bh); 450 ext4_unlock_group(sb, block_group); 451 unlock_buffer(bh); 452 if (err) { 453 ext4_error(sb, "Failed to init block bitmap for group " 454 "%u: %d", block_group, err); 455 goto out; 456 } 457 goto verify; 458 } 459 ext4_unlock_group(sb, block_group); 460 if (buffer_uptodate(bh)) { 461 /* 462 * if not uninit if bh is uptodate, 463 * bitmap is also uptodate 464 */ 465 set_bitmap_uptodate(bh); 466 unlock_buffer(bh); 467 goto verify; 468 } 469 /* 470 * submit the buffer_head for reading 471 */ 472 set_buffer_new(bh); 473 trace_ext4_read_block_bitmap_load(sb, block_group); 474 bh->b_end_io = ext4_end_bitmap_read; 475 get_bh(bh); 476 submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh); 477 return bh; 478 verify: 479 err = ext4_validate_block_bitmap(sb, desc, block_group, bh); 480 if (err) 481 goto out; 482 return bh; 483 out: 484 put_bh(bh); 485 return ERR_PTR(err); 486 } 487 488 /* Returns 0 on success, 1 on error */ 489 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 490 struct buffer_head *bh) 491 { 492 struct ext4_group_desc *desc; 493 494 if (!buffer_new(bh)) 495 return 0; 496 desc = ext4_get_group_desc(sb, block_group, NULL); 497 if (!desc) 498 return -EFSCORRUPTED; 499 wait_on_buffer(bh); 500 if (!buffer_uptodate(bh)) { 501 ext4_error(sb, "Cannot read block bitmap - " 502 "block_group = %u, block_bitmap = %llu", 503 block_group, (unsigned long long) bh->b_blocknr); 504 ext4_mark_group_bitmap_corrupted(sb, block_group, 505 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 506 return -EIO; 507 } 508 clear_buffer_new(bh); 509 /* Panic or remount fs read-only if block bitmap is invalid */ 510 return ext4_validate_block_bitmap(sb, desc, block_group, bh); 511 } 512 513 struct buffer_head * 514 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 515 { 516 struct buffer_head *bh; 517 int err; 518 519 bh = ext4_read_block_bitmap_nowait(sb, block_group); 520 if (IS_ERR(bh)) 521 return bh; 522 err = ext4_wait_block_bitmap(sb, block_group, bh); 523 if (err) { 524 put_bh(bh); 525 return ERR_PTR(err); 526 } 527 return bh; 528 } 529 530 /** 531 * ext4_has_free_clusters() 532 * @sbi: in-core super block structure. 533 * @nclusters: number of needed blocks 534 * @flags: flags from ext4_mb_new_blocks() 535 * 536 * Check if filesystem has nclusters free & available for allocation. 537 * On success return 1, return 0 on failure. 538 */ 539 static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 540 s64 nclusters, unsigned int flags) 541 { 542 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 543 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 544 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 545 546 free_clusters = percpu_counter_read_positive(fcc); 547 dirty_clusters = percpu_counter_read_positive(dcc); 548 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 549 550 /* 551 * r_blocks_count should always be multiple of the cluster ratio so 552 * we are safe to do a plane bit shift only. 553 */ 554 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 555 resv_clusters; 556 557 if (free_clusters - (nclusters + rsv + dirty_clusters) < 558 EXT4_FREECLUSTERS_WATERMARK) { 559 free_clusters = percpu_counter_sum_positive(fcc); 560 dirty_clusters = percpu_counter_sum_positive(dcc); 561 } 562 /* Check whether we have space after accounting for current 563 * dirty clusters & root reserved clusters. 564 */ 565 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 566 return 1; 567 568 /* Hm, nope. Are (enough) root reserved clusters available? */ 569 if (uid_eq(sbi->s_resuid, current_fsuid()) || 570 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 571 capable(CAP_SYS_RESOURCE) || 572 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 573 574 if (free_clusters >= (nclusters + dirty_clusters + 575 resv_clusters)) 576 return 1; 577 } 578 /* No free blocks. Let's see if we can dip into reserved pool */ 579 if (flags & EXT4_MB_USE_RESERVED) { 580 if (free_clusters >= (nclusters + dirty_clusters)) 581 return 1; 582 } 583 584 return 0; 585 } 586 587 int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 588 s64 nclusters, unsigned int flags) 589 { 590 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 591 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 592 return 0; 593 } else 594 return -ENOSPC; 595 } 596 597 /** 598 * ext4_should_retry_alloc() 599 * @sb: super block 600 * @retries number of attemps has been made 601 * 602 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if 603 * it is profitable to retry the operation, this function will wait 604 * for the current or committing transaction to complete, and then 605 * return TRUE. We will only retry once. 606 */ 607 int ext4_should_retry_alloc(struct super_block *sb, int *retries) 608 { 609 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || 610 (*retries)++ > 1 || 611 !EXT4_SB(sb)->s_journal) 612 return 0; 613 614 smp_mb(); 615 if (EXT4_SB(sb)->s_mb_free_pending == 0) 616 return 0; 617 618 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); 619 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); 620 return 1; 621 } 622 623 /* 624 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 625 * 626 * @handle: handle to this transaction 627 * @inode: file inode 628 * @goal: given target block(filesystem wide) 629 * @count: pointer to total number of clusters needed 630 * @errp: error code 631 * 632 * Return 1st allocated block number on success, *count stores total account 633 * error stores in errp pointer 634 */ 635 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 636 ext4_fsblk_t goal, unsigned int flags, 637 unsigned long *count, int *errp) 638 { 639 struct ext4_allocation_request ar; 640 ext4_fsblk_t ret; 641 642 memset(&ar, 0, sizeof(ar)); 643 /* Fill with neighbour allocated blocks */ 644 ar.inode = inode; 645 ar.goal = goal; 646 ar.len = count ? *count : 1; 647 ar.flags = flags; 648 649 ret = ext4_mb_new_blocks(handle, &ar, errp); 650 if (count) 651 *count = ar.len; 652 /* 653 * Account for the allocated meta blocks. We will never 654 * fail EDQUOT for metdata, but we do account for it. 655 */ 656 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 657 dquot_alloc_block_nofail(inode, 658 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 659 } 660 return ret; 661 } 662 663 /** 664 * ext4_count_free_clusters() -- count filesystem free clusters 665 * @sb: superblock 666 * 667 * Adds up the number of free clusters from each block group. 668 */ 669 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 670 { 671 ext4_fsblk_t desc_count; 672 struct ext4_group_desc *gdp; 673 ext4_group_t i; 674 ext4_group_t ngroups = ext4_get_groups_count(sb); 675 struct ext4_group_info *grp; 676 #ifdef EXT4FS_DEBUG 677 struct ext4_super_block *es; 678 ext4_fsblk_t bitmap_count; 679 unsigned int x; 680 struct buffer_head *bitmap_bh = NULL; 681 682 es = EXT4_SB(sb)->s_es; 683 desc_count = 0; 684 bitmap_count = 0; 685 gdp = NULL; 686 687 for (i = 0; i < ngroups; i++) { 688 gdp = ext4_get_group_desc(sb, i, NULL); 689 if (!gdp) 690 continue; 691 grp = NULL; 692 if (EXT4_SB(sb)->s_group_info) 693 grp = ext4_get_group_info(sb, i); 694 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 695 desc_count += ext4_free_group_clusters(sb, gdp); 696 brelse(bitmap_bh); 697 bitmap_bh = ext4_read_block_bitmap(sb, i); 698 if (IS_ERR(bitmap_bh)) { 699 bitmap_bh = NULL; 700 continue; 701 } 702 703 x = ext4_count_free(bitmap_bh->b_data, 704 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 705 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 706 i, ext4_free_group_clusters(sb, gdp), x); 707 bitmap_count += x; 708 } 709 brelse(bitmap_bh); 710 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 711 ", computed = %llu, %llu\n", 712 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 713 desc_count, bitmap_count); 714 return bitmap_count; 715 #else 716 desc_count = 0; 717 for (i = 0; i < ngroups; i++) { 718 gdp = ext4_get_group_desc(sb, i, NULL); 719 if (!gdp) 720 continue; 721 grp = NULL; 722 if (EXT4_SB(sb)->s_group_info) 723 grp = ext4_get_group_info(sb, i); 724 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 725 desc_count += ext4_free_group_clusters(sb, gdp); 726 } 727 728 return desc_count; 729 #endif 730 } 731 732 static inline int test_root(ext4_group_t a, int b) 733 { 734 while (1) { 735 if (a < b) 736 return 0; 737 if (a == b) 738 return 1; 739 if ((a % b) != 0) 740 return 0; 741 a = a / b; 742 } 743 } 744 745 /** 746 * ext4_bg_has_super - number of blocks used by the superblock in group 747 * @sb: superblock for filesystem 748 * @group: group number to check 749 * 750 * Return the number of blocks used by the superblock (primary or backup) 751 * in this group. Currently this will be only 0 or 1. 752 */ 753 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 754 { 755 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 756 757 if (group == 0) 758 return 1; 759 if (ext4_has_feature_sparse_super2(sb)) { 760 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 761 group == le32_to_cpu(es->s_backup_bgs[1])) 762 return 1; 763 return 0; 764 } 765 if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) 766 return 1; 767 if (!(group & 1)) 768 return 0; 769 if (test_root(group, 3) || (test_root(group, 5)) || 770 test_root(group, 7)) 771 return 1; 772 773 return 0; 774 } 775 776 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 777 ext4_group_t group) 778 { 779 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 780 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 781 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 782 783 if (group == first || group == first + 1 || group == last) 784 return 1; 785 return 0; 786 } 787 788 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 789 ext4_group_t group) 790 { 791 if (!ext4_bg_has_super(sb, group)) 792 return 0; 793 794 if (ext4_has_feature_meta_bg(sb)) 795 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 796 else 797 return EXT4_SB(sb)->s_gdb_count; 798 } 799 800 /** 801 * ext4_bg_num_gdb - number of blocks used by the group table in group 802 * @sb: superblock for filesystem 803 * @group: group number to check 804 * 805 * Return the number of blocks used by the group descriptor table 806 * (primary or backup) in this group. In the future there may be a 807 * different number of descriptor blocks in each group. 808 */ 809 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 810 { 811 unsigned long first_meta_bg = 812 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 813 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 814 815 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) 816 return ext4_bg_num_gdb_nometa(sb, group); 817 818 return ext4_bg_num_gdb_meta(sb,group); 819 820 } 821 822 /* 823 * This function returns the number of file system metadata clusters at 824 * the beginning of a block group, including the reserved gdt blocks. 825 */ 826 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 827 ext4_group_t block_group) 828 { 829 struct ext4_sb_info *sbi = EXT4_SB(sb); 830 unsigned num; 831 832 /* Check for superblock and gdt backups in this group */ 833 num = ext4_bg_has_super(sb, block_group); 834 835 if (!ext4_has_feature_meta_bg(sb) || 836 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 837 sbi->s_desc_per_block) { 838 if (num) { 839 num += ext4_bg_num_gdb(sb, block_group); 840 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 841 } 842 } else { /* For META_BG_BLOCK_GROUPS */ 843 num += ext4_bg_num_gdb(sb, block_group); 844 } 845 return EXT4_NUM_B2C(sbi, num); 846 } 847 /** 848 * ext4_inode_to_goal_block - return a hint for block allocation 849 * @inode: inode for block allocation 850 * 851 * Return the ideal location to start allocating blocks for a 852 * newly created inode. 853 */ 854 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 855 { 856 struct ext4_inode_info *ei = EXT4_I(inode); 857 ext4_group_t block_group; 858 ext4_grpblk_t colour; 859 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 860 ext4_fsblk_t bg_start; 861 ext4_fsblk_t last_block; 862 863 block_group = ei->i_block_group; 864 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 865 /* 866 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 867 * block groups per flexgroup, reserve the first block 868 * group for directories and special files. Regular 869 * files will start at the second block group. This 870 * tends to speed up directory access and improves 871 * fsck times. 872 */ 873 block_group &= ~(flex_size-1); 874 if (S_ISREG(inode->i_mode)) 875 block_group++; 876 } 877 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 878 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 879 880 /* 881 * If we are doing delayed allocation, we don't need take 882 * colour into account. 883 */ 884 if (test_opt(inode->i_sb, DELALLOC)) 885 return bg_start; 886 887 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 888 colour = (current->pid % 16) * 889 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 890 else 891 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 892 return bg_start + colour; 893 } 894 895