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; 187 188 J_ASSERT_BH(bh, buffer_locked(bh)); 189 190 /* If checksum is bad mark all blocks used to prevent allocation 191 * essentially implementing a per-group read-only flag. */ 192 if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) { 193 ext4_mark_group_bitmap_corrupted(sb, block_group, 194 EXT4_GROUP_INFO_BBITMAP_CORRUPT | 195 EXT4_GROUP_INFO_IBITMAP_CORRUPT); 196 return -EFSBADCRC; 197 } 198 memset(bh->b_data, 0, sb->s_blocksize); 199 200 bit_max = ext4_num_base_meta_clusters(sb, block_group); 201 if ((bit_max >> 3) >= bh->b_size) 202 return -EFSCORRUPTED; 203 204 for (bit = 0; bit < bit_max; bit++) 205 ext4_set_bit(bit, bh->b_data); 206 207 start = ext4_group_first_block_no(sb, block_group); 208 209 /* Set bits for block and inode bitmaps, and inode table */ 210 tmp = ext4_block_bitmap(sb, gdp); 211 if (ext4_block_in_group(sb, tmp, block_group)) 212 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 213 214 tmp = ext4_inode_bitmap(sb, gdp); 215 if (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_table(sb, gdp); 219 for (; tmp < ext4_inode_table(sb, gdp) + 220 sbi->s_itb_per_group; tmp++) { 221 if (ext4_block_in_group(sb, tmp, block_group)) 222 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 223 } 224 225 /* 226 * Also if the number of blocks within the group is less than 227 * the blocksize * 8 ( which is the size of bitmap ), set rest 228 * of the block bitmap to 1 229 */ 230 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), 231 sb->s_blocksize * 8, bh->b_data); 232 return 0; 233 } 234 235 /* Return the number of free blocks in a block group. It is used when 236 * the block bitmap is uninitialized, so we can't just count the bits 237 * in the bitmap. */ 238 unsigned ext4_free_clusters_after_init(struct super_block *sb, 239 ext4_group_t block_group, 240 struct ext4_group_desc *gdp) 241 { 242 return num_clusters_in_group(sb, block_group) - 243 ext4_num_overhead_clusters(sb, block_group, gdp); 244 } 245 246 /* 247 * The free blocks are managed by bitmaps. A file system contains several 248 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 249 * block for inodes, N blocks for the inode table and data blocks. 250 * 251 * The file system contains group descriptors which are located after the 252 * super block. Each descriptor contains the number of the bitmap block and 253 * the free blocks count in the block. The descriptors are loaded in memory 254 * when a file system is mounted (see ext4_fill_super). 255 */ 256 257 /** 258 * ext4_get_group_desc() -- load group descriptor from disk 259 * @sb: super block 260 * @block_group: given block group 261 * @bh: pointer to the buffer head to store the block 262 * group descriptor 263 */ 264 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, 265 ext4_group_t block_group, 266 struct buffer_head **bh) 267 { 268 unsigned int group_desc; 269 unsigned int offset; 270 ext4_group_t ngroups = ext4_get_groups_count(sb); 271 struct ext4_group_desc *desc; 272 struct ext4_sb_info *sbi = EXT4_SB(sb); 273 274 if (block_group >= ngroups) { 275 ext4_error(sb, "block_group >= groups_count - block_group = %u," 276 " groups_count = %u", block_group, ngroups); 277 278 return NULL; 279 } 280 281 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 282 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 283 if (!sbi->s_group_desc[group_desc]) { 284 ext4_error(sb, "Group descriptor not loaded - " 285 "block_group = %u, group_desc = %u, desc = %u", 286 block_group, group_desc, offset); 287 return NULL; 288 } 289 290 desc = (struct ext4_group_desc *)( 291 (__u8 *)sbi->s_group_desc[group_desc]->b_data + 292 offset * EXT4_DESC_SIZE(sb)); 293 if (bh) 294 *bh = sbi->s_group_desc[group_desc]; 295 return desc; 296 } 297 298 /* 299 * Return the block number which was discovered to be invalid, or 0 if 300 * the block bitmap is valid. 301 */ 302 static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, 303 struct ext4_group_desc *desc, 304 ext4_group_t block_group, 305 struct buffer_head *bh) 306 { 307 struct ext4_sb_info *sbi = EXT4_SB(sb); 308 ext4_grpblk_t offset; 309 ext4_grpblk_t next_zero_bit; 310 ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); 311 ext4_fsblk_t blk; 312 ext4_fsblk_t group_first_block; 313 314 if (ext4_has_feature_flex_bg(sb)) { 315 /* with FLEX_BG, the inode/block bitmaps and itable 316 * blocks may not be in the group at all 317 * so the bitmap validation will be skipped for those groups 318 * or it has to also read the block group where the bitmaps 319 * are located to verify they are set. 320 */ 321 return 0; 322 } 323 group_first_block = ext4_group_first_block_no(sb, block_group); 324 325 /* check whether block bitmap block number is set */ 326 blk = ext4_block_bitmap(sb, desc); 327 offset = blk - group_first_block; 328 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 329 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 330 /* bad block bitmap */ 331 return blk; 332 333 /* check whether the inode bitmap block number is set */ 334 blk = ext4_inode_bitmap(sb, desc); 335 offset = blk - group_first_block; 336 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 337 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 338 /* bad block bitmap */ 339 return blk; 340 341 /* check whether the inode table block number is set */ 342 blk = ext4_inode_table(sb, desc); 343 offset = blk - group_first_block; 344 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 345 EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit) 346 return blk; 347 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 348 EXT4_B2C(sbi, offset + sbi->s_itb_per_group), 349 EXT4_B2C(sbi, offset)); 350 if (next_zero_bit < 351 EXT4_B2C(sbi, offset + sbi->s_itb_per_group)) 352 /* bad bitmap for inode tables */ 353 return blk; 354 return 0; 355 } 356 357 static int ext4_validate_block_bitmap(struct super_block *sb, 358 struct ext4_group_desc *desc, 359 ext4_group_t block_group, 360 struct buffer_head *bh) 361 { 362 ext4_fsblk_t blk; 363 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); 364 365 if (buffer_verified(bh)) 366 return 0; 367 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 368 return -EFSCORRUPTED; 369 370 ext4_lock_group(sb, block_group); 371 if (buffer_verified(bh)) 372 goto verified; 373 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, 374 desc, bh))) { 375 ext4_unlock_group(sb, block_group); 376 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 377 ext4_mark_group_bitmap_corrupted(sb, block_group, 378 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 379 return -EFSBADCRC; 380 } 381 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 382 if (unlikely(blk != 0)) { 383 ext4_unlock_group(sb, block_group); 384 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 385 block_group, blk); 386 ext4_mark_group_bitmap_corrupted(sb, block_group, 387 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 388 return -EFSCORRUPTED; 389 } 390 set_buffer_verified(bh); 391 verified: 392 ext4_unlock_group(sb, block_group); 393 return 0; 394 } 395 396 /** 397 * ext4_read_block_bitmap_nowait() 398 * @sb: super block 399 * @block_group: given block group 400 * 401 * Read the bitmap for a given block_group,and validate the 402 * bits for block/inode/inode tables are set in the bitmaps 403 * 404 * Return buffer_head on success or NULL in case of failure. 405 */ 406 struct buffer_head * 407 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) 408 { 409 struct ext4_group_desc *desc; 410 struct ext4_sb_info *sbi = EXT4_SB(sb); 411 struct buffer_head *bh; 412 ext4_fsblk_t bitmap_blk; 413 int err; 414 415 desc = ext4_get_group_desc(sb, block_group, NULL); 416 if (!desc) 417 return ERR_PTR(-EFSCORRUPTED); 418 bitmap_blk = ext4_block_bitmap(sb, desc); 419 if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || 420 (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { 421 ext4_error(sb, "Invalid block bitmap block %llu in " 422 "block_group %u", bitmap_blk, block_group); 423 ext4_mark_group_bitmap_corrupted(sb, block_group, 424 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 425 return ERR_PTR(-EFSCORRUPTED); 426 } 427 bh = sb_getblk(sb, bitmap_blk); 428 if (unlikely(!bh)) { 429 ext4_warning(sb, "Cannot get buffer for block bitmap - " 430 "block_group = %u, block_bitmap = %llu", 431 block_group, bitmap_blk); 432 return ERR_PTR(-ENOMEM); 433 } 434 435 if (bitmap_uptodate(bh)) 436 goto verify; 437 438 lock_buffer(bh); 439 if (bitmap_uptodate(bh)) { 440 unlock_buffer(bh); 441 goto verify; 442 } 443 ext4_lock_group(sb, block_group); 444 if (ext4_has_group_desc_csum(sb) && 445 (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { 446 if (block_group == 0) { 447 ext4_unlock_group(sb, block_group); 448 unlock_buffer(bh); 449 ext4_error(sb, "Block bitmap for bg 0 marked " 450 "uninitialized"); 451 err = -EFSCORRUPTED; 452 goto out; 453 } 454 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 455 set_bitmap_uptodate(bh); 456 set_buffer_uptodate(bh); 457 set_buffer_verified(bh); 458 ext4_unlock_group(sb, block_group); 459 unlock_buffer(bh); 460 if (err) { 461 ext4_error(sb, "Failed to init block bitmap for group " 462 "%u: %d", block_group, err); 463 goto out; 464 } 465 goto verify; 466 } 467 ext4_unlock_group(sb, block_group); 468 if (buffer_uptodate(bh)) { 469 /* 470 * if not uninit if bh is uptodate, 471 * bitmap is also uptodate 472 */ 473 set_bitmap_uptodate(bh); 474 unlock_buffer(bh); 475 goto verify; 476 } 477 /* 478 * submit the buffer_head for reading 479 */ 480 set_buffer_new(bh); 481 trace_ext4_read_block_bitmap_load(sb, block_group); 482 bh->b_end_io = ext4_end_bitmap_read; 483 get_bh(bh); 484 submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh); 485 return bh; 486 verify: 487 err = ext4_validate_block_bitmap(sb, desc, block_group, bh); 488 if (err) 489 goto out; 490 return bh; 491 out: 492 put_bh(bh); 493 return ERR_PTR(err); 494 } 495 496 /* Returns 0 on success, 1 on error */ 497 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 498 struct buffer_head *bh) 499 { 500 struct ext4_group_desc *desc; 501 502 if (!buffer_new(bh)) 503 return 0; 504 desc = ext4_get_group_desc(sb, block_group, NULL); 505 if (!desc) 506 return -EFSCORRUPTED; 507 wait_on_buffer(bh); 508 if (!buffer_uptodate(bh)) { 509 ext4_error(sb, "Cannot read block bitmap - " 510 "block_group = %u, block_bitmap = %llu", 511 block_group, (unsigned long long) bh->b_blocknr); 512 ext4_mark_group_bitmap_corrupted(sb, block_group, 513 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 514 return -EIO; 515 } 516 clear_buffer_new(bh); 517 /* Panic or remount fs read-only if block bitmap is invalid */ 518 return ext4_validate_block_bitmap(sb, desc, block_group, bh); 519 } 520 521 struct buffer_head * 522 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 523 { 524 struct buffer_head *bh; 525 int err; 526 527 bh = ext4_read_block_bitmap_nowait(sb, block_group); 528 if (IS_ERR(bh)) 529 return bh; 530 err = ext4_wait_block_bitmap(sb, block_group, bh); 531 if (err) { 532 put_bh(bh); 533 return ERR_PTR(err); 534 } 535 return bh; 536 } 537 538 /** 539 * ext4_has_free_clusters() 540 * @sbi: in-core super block structure. 541 * @nclusters: number of needed blocks 542 * @flags: flags from ext4_mb_new_blocks() 543 * 544 * Check if filesystem has nclusters free & available for allocation. 545 * On success return 1, return 0 on failure. 546 */ 547 static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 548 s64 nclusters, unsigned int flags) 549 { 550 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 551 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 552 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 553 554 free_clusters = percpu_counter_read_positive(fcc); 555 dirty_clusters = percpu_counter_read_positive(dcc); 556 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 557 558 /* 559 * r_blocks_count should always be multiple of the cluster ratio so 560 * we are safe to do a plane bit shift only. 561 */ 562 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 563 resv_clusters; 564 565 if (free_clusters - (nclusters + rsv + dirty_clusters) < 566 EXT4_FREECLUSTERS_WATERMARK) { 567 free_clusters = percpu_counter_sum_positive(fcc); 568 dirty_clusters = percpu_counter_sum_positive(dcc); 569 } 570 /* Check whether we have space after accounting for current 571 * dirty clusters & root reserved clusters. 572 */ 573 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 574 return 1; 575 576 /* Hm, nope. Are (enough) root reserved clusters available? */ 577 if (uid_eq(sbi->s_resuid, current_fsuid()) || 578 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 579 capable(CAP_SYS_RESOURCE) || 580 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 581 582 if (free_clusters >= (nclusters + dirty_clusters + 583 resv_clusters)) 584 return 1; 585 } 586 /* No free blocks. Let's see if we can dip into reserved pool */ 587 if (flags & EXT4_MB_USE_RESERVED) { 588 if (free_clusters >= (nclusters + dirty_clusters)) 589 return 1; 590 } 591 592 return 0; 593 } 594 595 int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 596 s64 nclusters, unsigned int flags) 597 { 598 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 599 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 600 return 0; 601 } else 602 return -ENOSPC; 603 } 604 605 /** 606 * ext4_should_retry_alloc() - check if a block allocation should be retried 607 * @sb: super block 608 * @retries: number of attemps has been made 609 * 610 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if 611 * it is profitable to retry the operation, this function will wait 612 * for the current or committing transaction to complete, and then 613 * return TRUE. We will only retry once. 614 */ 615 int ext4_should_retry_alloc(struct super_block *sb, int *retries) 616 { 617 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || 618 (*retries)++ > 1 || 619 !EXT4_SB(sb)->s_journal) 620 return 0; 621 622 smp_mb(); 623 if (EXT4_SB(sb)->s_mb_free_pending == 0) 624 return 0; 625 626 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); 627 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); 628 return 1; 629 } 630 631 /* 632 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 633 * 634 * @handle: handle to this transaction 635 * @inode: file inode 636 * @goal: given target block(filesystem wide) 637 * @count: pointer to total number of clusters needed 638 * @errp: error code 639 * 640 * Return 1st allocated block number on success, *count stores total account 641 * error stores in errp pointer 642 */ 643 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 644 ext4_fsblk_t goal, unsigned int flags, 645 unsigned long *count, int *errp) 646 { 647 struct ext4_allocation_request ar; 648 ext4_fsblk_t ret; 649 650 memset(&ar, 0, sizeof(ar)); 651 /* Fill with neighbour allocated blocks */ 652 ar.inode = inode; 653 ar.goal = goal; 654 ar.len = count ? *count : 1; 655 ar.flags = flags; 656 657 ret = ext4_mb_new_blocks(handle, &ar, errp); 658 if (count) 659 *count = ar.len; 660 /* 661 * Account for the allocated meta blocks. We will never 662 * fail EDQUOT for metdata, but we do account for it. 663 */ 664 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 665 dquot_alloc_block_nofail(inode, 666 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 667 } 668 return ret; 669 } 670 671 /** 672 * ext4_count_free_clusters() -- count filesystem free clusters 673 * @sb: superblock 674 * 675 * Adds up the number of free clusters from each block group. 676 */ 677 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 678 { 679 ext4_fsblk_t desc_count; 680 struct ext4_group_desc *gdp; 681 ext4_group_t i; 682 ext4_group_t ngroups = ext4_get_groups_count(sb); 683 struct ext4_group_info *grp; 684 #ifdef EXT4FS_DEBUG 685 struct ext4_super_block *es; 686 ext4_fsblk_t bitmap_count; 687 unsigned int x; 688 struct buffer_head *bitmap_bh = NULL; 689 690 es = EXT4_SB(sb)->s_es; 691 desc_count = 0; 692 bitmap_count = 0; 693 gdp = NULL; 694 695 for (i = 0; i < ngroups; i++) { 696 gdp = ext4_get_group_desc(sb, i, NULL); 697 if (!gdp) 698 continue; 699 grp = NULL; 700 if (EXT4_SB(sb)->s_group_info) 701 grp = ext4_get_group_info(sb, i); 702 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 703 desc_count += ext4_free_group_clusters(sb, gdp); 704 brelse(bitmap_bh); 705 bitmap_bh = ext4_read_block_bitmap(sb, i); 706 if (IS_ERR(bitmap_bh)) { 707 bitmap_bh = NULL; 708 continue; 709 } 710 711 x = ext4_count_free(bitmap_bh->b_data, 712 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 713 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 714 i, ext4_free_group_clusters(sb, gdp), x); 715 bitmap_count += x; 716 } 717 brelse(bitmap_bh); 718 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 719 ", computed = %llu, %llu\n", 720 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 721 desc_count, bitmap_count); 722 return bitmap_count; 723 #else 724 desc_count = 0; 725 for (i = 0; i < ngroups; i++) { 726 gdp = ext4_get_group_desc(sb, i, NULL); 727 if (!gdp) 728 continue; 729 grp = NULL; 730 if (EXT4_SB(sb)->s_group_info) 731 grp = ext4_get_group_info(sb, i); 732 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 733 desc_count += ext4_free_group_clusters(sb, gdp); 734 } 735 736 return desc_count; 737 #endif 738 } 739 740 static inline int test_root(ext4_group_t a, int b) 741 { 742 while (1) { 743 if (a < b) 744 return 0; 745 if (a == b) 746 return 1; 747 if ((a % b) != 0) 748 return 0; 749 a = a / b; 750 } 751 } 752 753 /** 754 * ext4_bg_has_super - number of blocks used by the superblock in group 755 * @sb: superblock for filesystem 756 * @group: group number to check 757 * 758 * Return the number of blocks used by the superblock (primary or backup) 759 * in this group. Currently this will be only 0 or 1. 760 */ 761 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 762 { 763 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 764 765 if (group == 0) 766 return 1; 767 if (ext4_has_feature_sparse_super2(sb)) { 768 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 769 group == le32_to_cpu(es->s_backup_bgs[1])) 770 return 1; 771 return 0; 772 } 773 if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) 774 return 1; 775 if (!(group & 1)) 776 return 0; 777 if (test_root(group, 3) || (test_root(group, 5)) || 778 test_root(group, 7)) 779 return 1; 780 781 return 0; 782 } 783 784 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 785 ext4_group_t group) 786 { 787 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 788 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 789 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 790 791 if (group == first || group == first + 1 || group == last) 792 return 1; 793 return 0; 794 } 795 796 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 797 ext4_group_t group) 798 { 799 if (!ext4_bg_has_super(sb, group)) 800 return 0; 801 802 if (ext4_has_feature_meta_bg(sb)) 803 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 804 else 805 return EXT4_SB(sb)->s_gdb_count; 806 } 807 808 /** 809 * ext4_bg_num_gdb - number of blocks used by the group table in group 810 * @sb: superblock for filesystem 811 * @group: group number to check 812 * 813 * Return the number of blocks used by the group descriptor table 814 * (primary or backup) in this group. In the future there may be a 815 * different number of descriptor blocks in each group. 816 */ 817 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 818 { 819 unsigned long first_meta_bg = 820 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 821 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 822 823 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) 824 return ext4_bg_num_gdb_nometa(sb, group); 825 826 return ext4_bg_num_gdb_meta(sb,group); 827 828 } 829 830 /* 831 * This function returns the number of file system metadata clusters at 832 * the beginning of a block group, including the reserved gdt blocks. 833 */ 834 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 835 ext4_group_t block_group) 836 { 837 struct ext4_sb_info *sbi = EXT4_SB(sb); 838 unsigned num; 839 840 /* Check for superblock and gdt backups in this group */ 841 num = ext4_bg_has_super(sb, block_group); 842 843 if (!ext4_has_feature_meta_bg(sb) || 844 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 845 sbi->s_desc_per_block) { 846 if (num) { 847 num += ext4_bg_num_gdb(sb, block_group); 848 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 849 } 850 } else { /* For META_BG_BLOCK_GROUPS */ 851 num += ext4_bg_num_gdb(sb, block_group); 852 } 853 return EXT4_NUM_B2C(sbi, num); 854 } 855 /** 856 * ext4_inode_to_goal_block - return a hint for block allocation 857 * @inode: inode for block allocation 858 * 859 * Return the ideal location to start allocating blocks for a 860 * newly created inode. 861 */ 862 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 863 { 864 struct ext4_inode_info *ei = EXT4_I(inode); 865 ext4_group_t block_group; 866 ext4_grpblk_t colour; 867 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 868 ext4_fsblk_t bg_start; 869 ext4_fsblk_t last_block; 870 871 block_group = ei->i_block_group; 872 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 873 /* 874 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 875 * block groups per flexgroup, reserve the first block 876 * group for directories and special files. Regular 877 * files will start at the second block group. This 878 * tends to speed up directory access and improves 879 * fsck times. 880 */ 881 block_group &= ~(flex_size-1); 882 if (S_ISREG(inode->i_mode)) 883 block_group++; 884 } 885 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 886 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 887 888 /* 889 * If we are doing delayed allocation, we don't need take 890 * colour into account. 891 */ 892 if (test_opt(inode->i_sb, DELALLOC)) 893 return bg_start; 894 895 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 896 colour = (current->pid % 16) * 897 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 898 else 899 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 900 return bg_start + colour; 901 } 902 903