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 struct buffer_head *bh_p; 274 275 if (block_group >= ngroups) { 276 ext4_error(sb, "block_group >= groups_count - block_group = %u," 277 " groups_count = %u", block_group, ngroups); 278 279 return NULL; 280 } 281 282 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 283 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 284 bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc); 285 /* 286 * sbi_array_rcu_deref returns with rcu unlocked, this is ok since 287 * the pointer being dereferenced won't be dereferenced again. By 288 * looking at the usage in add_new_gdb() the value isn't modified, 289 * just the pointer, and so it remains valid. 290 */ 291 if (!bh_p) { 292 ext4_error(sb, "Group descriptor not loaded - " 293 "block_group = %u, group_desc = %u, desc = %u", 294 block_group, group_desc, offset); 295 return NULL; 296 } 297 298 desc = (struct ext4_group_desc *)( 299 (__u8 *)bh_p->b_data + 300 offset * EXT4_DESC_SIZE(sb)); 301 if (bh) 302 *bh = bh_p; 303 return desc; 304 } 305 306 /* 307 * Return the block number which was discovered to be invalid, or 0 if 308 * the block bitmap is valid. 309 */ 310 static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, 311 struct ext4_group_desc *desc, 312 ext4_group_t block_group, 313 struct buffer_head *bh) 314 { 315 struct ext4_sb_info *sbi = EXT4_SB(sb); 316 ext4_grpblk_t offset; 317 ext4_grpblk_t next_zero_bit; 318 ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); 319 ext4_fsblk_t blk; 320 ext4_fsblk_t group_first_block; 321 322 if (ext4_has_feature_flex_bg(sb)) { 323 /* with FLEX_BG, the inode/block bitmaps and itable 324 * blocks may not be in the group at all 325 * so the bitmap validation will be skipped for those groups 326 * or it has to also read the block group where the bitmaps 327 * are located to verify they are set. 328 */ 329 return 0; 330 } 331 group_first_block = ext4_group_first_block_no(sb, block_group); 332 333 /* check whether block bitmap block number is set */ 334 blk = ext4_block_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 bitmap block number is set */ 342 blk = ext4_inode_bitmap(sb, desc); 343 offset = blk - group_first_block; 344 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 345 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 346 /* bad block bitmap */ 347 return blk; 348 349 /* check whether the inode table block number is set */ 350 blk = ext4_inode_table(sb, desc); 351 offset = blk - group_first_block; 352 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 353 EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit) 354 return blk; 355 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 356 EXT4_B2C(sbi, offset + sbi->s_itb_per_group), 357 EXT4_B2C(sbi, offset)); 358 if (next_zero_bit < 359 EXT4_B2C(sbi, offset + sbi->s_itb_per_group)) 360 /* bad bitmap for inode tables */ 361 return blk; 362 return 0; 363 } 364 365 static int ext4_validate_block_bitmap(struct super_block *sb, 366 struct ext4_group_desc *desc, 367 ext4_group_t block_group, 368 struct buffer_head *bh) 369 { 370 ext4_fsblk_t blk; 371 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); 372 373 if (buffer_verified(bh)) 374 return 0; 375 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 376 return -EFSCORRUPTED; 377 378 ext4_lock_group(sb, block_group); 379 if (buffer_verified(bh)) 380 goto verified; 381 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, 382 desc, bh) || 383 ext4_simulate_fail(sb, EXT4_SIM_BBITMAP_CRC))) { 384 ext4_unlock_group(sb, block_group); 385 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 386 ext4_mark_group_bitmap_corrupted(sb, block_group, 387 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 388 return -EFSBADCRC; 389 } 390 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 391 if (unlikely(blk != 0)) { 392 ext4_unlock_group(sb, block_group); 393 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 394 block_group, blk); 395 ext4_mark_group_bitmap_corrupted(sb, block_group, 396 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 397 return -EFSCORRUPTED; 398 } 399 set_buffer_verified(bh); 400 verified: 401 ext4_unlock_group(sb, block_group); 402 return 0; 403 } 404 405 /** 406 * ext4_read_block_bitmap_nowait() 407 * @sb: super block 408 * @block_group: given block group 409 * 410 * Read the bitmap for a given block_group,and validate the 411 * bits for block/inode/inode tables are set in the bitmaps 412 * 413 * Return buffer_head on success or NULL in case of failure. 414 */ 415 struct buffer_head * 416 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) 417 { 418 struct ext4_group_desc *desc; 419 struct ext4_sb_info *sbi = EXT4_SB(sb); 420 struct buffer_head *bh; 421 ext4_fsblk_t bitmap_blk; 422 int err; 423 424 desc = ext4_get_group_desc(sb, block_group, NULL); 425 if (!desc) 426 return ERR_PTR(-EFSCORRUPTED); 427 bitmap_blk = ext4_block_bitmap(sb, desc); 428 if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || 429 (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { 430 ext4_error(sb, "Invalid block bitmap block %llu in " 431 "block_group %u", bitmap_blk, block_group); 432 ext4_mark_group_bitmap_corrupted(sb, block_group, 433 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 434 return ERR_PTR(-EFSCORRUPTED); 435 } 436 bh = sb_getblk(sb, bitmap_blk); 437 if (unlikely(!bh)) { 438 ext4_warning(sb, "Cannot get buffer for block bitmap - " 439 "block_group = %u, block_bitmap = %llu", 440 block_group, bitmap_blk); 441 return ERR_PTR(-ENOMEM); 442 } 443 444 if (bitmap_uptodate(bh)) 445 goto verify; 446 447 lock_buffer(bh); 448 if (bitmap_uptodate(bh)) { 449 unlock_buffer(bh); 450 goto verify; 451 } 452 ext4_lock_group(sb, block_group); 453 if (ext4_has_group_desc_csum(sb) && 454 (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { 455 if (block_group == 0) { 456 ext4_unlock_group(sb, block_group); 457 unlock_buffer(bh); 458 ext4_error(sb, "Block bitmap for bg 0 marked " 459 "uninitialized"); 460 err = -EFSCORRUPTED; 461 goto out; 462 } 463 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 464 set_bitmap_uptodate(bh); 465 set_buffer_uptodate(bh); 466 set_buffer_verified(bh); 467 ext4_unlock_group(sb, block_group); 468 unlock_buffer(bh); 469 if (err) { 470 ext4_error(sb, "Failed to init block bitmap for group " 471 "%u: %d", block_group, err); 472 goto out; 473 } 474 goto verify; 475 } 476 ext4_unlock_group(sb, block_group); 477 if (buffer_uptodate(bh)) { 478 /* 479 * if not uninit if bh is uptodate, 480 * bitmap is also uptodate 481 */ 482 set_bitmap_uptodate(bh); 483 unlock_buffer(bh); 484 goto verify; 485 } 486 /* 487 * submit the buffer_head for reading 488 */ 489 set_buffer_new(bh); 490 trace_ext4_read_block_bitmap_load(sb, block_group); 491 bh->b_end_io = ext4_end_bitmap_read; 492 get_bh(bh); 493 submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh); 494 return bh; 495 verify: 496 err = ext4_validate_block_bitmap(sb, desc, block_group, bh); 497 if (err) 498 goto out; 499 return bh; 500 out: 501 put_bh(bh); 502 return ERR_PTR(err); 503 } 504 505 /* Returns 0 on success, 1 on error */ 506 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 507 struct buffer_head *bh) 508 { 509 struct ext4_group_desc *desc; 510 511 if (!buffer_new(bh)) 512 return 0; 513 desc = ext4_get_group_desc(sb, block_group, NULL); 514 if (!desc) 515 return -EFSCORRUPTED; 516 wait_on_buffer(bh); 517 ext4_simulate_fail_bh(sb, bh, EXT4_SIM_BBITMAP_EIO); 518 if (!buffer_uptodate(bh)) { 519 ext4_set_errno(sb, EIO); 520 ext4_error(sb, "Cannot read block bitmap - " 521 "block_group = %u, block_bitmap = %llu", 522 block_group, (unsigned long long) bh->b_blocknr); 523 ext4_mark_group_bitmap_corrupted(sb, block_group, 524 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 525 return -EIO; 526 } 527 clear_buffer_new(bh); 528 /* Panic or remount fs read-only if block bitmap is invalid */ 529 return ext4_validate_block_bitmap(sb, desc, block_group, bh); 530 } 531 532 struct buffer_head * 533 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 534 { 535 struct buffer_head *bh; 536 int err; 537 538 bh = ext4_read_block_bitmap_nowait(sb, block_group); 539 if (IS_ERR(bh)) 540 return bh; 541 err = ext4_wait_block_bitmap(sb, block_group, bh); 542 if (err) { 543 put_bh(bh); 544 return ERR_PTR(err); 545 } 546 return bh; 547 } 548 549 /** 550 * ext4_has_free_clusters() 551 * @sbi: in-core super block structure. 552 * @nclusters: number of needed blocks 553 * @flags: flags from ext4_mb_new_blocks() 554 * 555 * Check if filesystem has nclusters free & available for allocation. 556 * On success return 1, return 0 on failure. 557 */ 558 static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 559 s64 nclusters, unsigned int flags) 560 { 561 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 562 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 563 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 564 565 free_clusters = percpu_counter_read_positive(fcc); 566 dirty_clusters = percpu_counter_read_positive(dcc); 567 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 568 569 /* 570 * r_blocks_count should always be multiple of the cluster ratio so 571 * we are safe to do a plane bit shift only. 572 */ 573 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 574 resv_clusters; 575 576 if (free_clusters - (nclusters + rsv + dirty_clusters) < 577 EXT4_FREECLUSTERS_WATERMARK) { 578 free_clusters = percpu_counter_sum_positive(fcc); 579 dirty_clusters = percpu_counter_sum_positive(dcc); 580 } 581 /* Check whether we have space after accounting for current 582 * dirty clusters & root reserved clusters. 583 */ 584 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 585 return 1; 586 587 /* Hm, nope. Are (enough) root reserved clusters available? */ 588 if (uid_eq(sbi->s_resuid, current_fsuid()) || 589 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 590 capable(CAP_SYS_RESOURCE) || 591 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 592 593 if (free_clusters >= (nclusters + dirty_clusters + 594 resv_clusters)) 595 return 1; 596 } 597 /* No free blocks. Let's see if we can dip into reserved pool */ 598 if (flags & EXT4_MB_USE_RESERVED) { 599 if (free_clusters >= (nclusters + dirty_clusters)) 600 return 1; 601 } 602 603 return 0; 604 } 605 606 int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 607 s64 nclusters, unsigned int flags) 608 { 609 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 610 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 611 return 0; 612 } else 613 return -ENOSPC; 614 } 615 616 /** 617 * ext4_should_retry_alloc() - check if a block allocation should be retried 618 * @sb: super block 619 * @retries: number of attemps has been made 620 * 621 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if 622 * it is profitable to retry the operation, this function will wait 623 * for the current or committing transaction to complete, and then 624 * return TRUE. We will only retry once. 625 */ 626 int ext4_should_retry_alloc(struct super_block *sb, int *retries) 627 { 628 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || 629 (*retries)++ > 1 || 630 !EXT4_SB(sb)->s_journal) 631 return 0; 632 633 smp_mb(); 634 if (EXT4_SB(sb)->s_mb_free_pending == 0) 635 return 0; 636 637 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); 638 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); 639 return 1; 640 } 641 642 /* 643 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 644 * 645 * @handle: handle to this transaction 646 * @inode: file inode 647 * @goal: given target block(filesystem wide) 648 * @count: pointer to total number of clusters needed 649 * @errp: error code 650 * 651 * Return 1st allocated block number on success, *count stores total account 652 * error stores in errp pointer 653 */ 654 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 655 ext4_fsblk_t goal, unsigned int flags, 656 unsigned long *count, int *errp) 657 { 658 struct ext4_allocation_request ar; 659 ext4_fsblk_t ret; 660 661 memset(&ar, 0, sizeof(ar)); 662 /* Fill with neighbour allocated blocks */ 663 ar.inode = inode; 664 ar.goal = goal; 665 ar.len = count ? *count : 1; 666 ar.flags = flags; 667 668 ret = ext4_mb_new_blocks(handle, &ar, errp); 669 if (count) 670 *count = ar.len; 671 /* 672 * Account for the allocated meta blocks. We will never 673 * fail EDQUOT for metdata, but we do account for it. 674 */ 675 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 676 dquot_alloc_block_nofail(inode, 677 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 678 } 679 return ret; 680 } 681 682 /** 683 * ext4_count_free_clusters() -- count filesystem free clusters 684 * @sb: superblock 685 * 686 * Adds up the number of free clusters from each block group. 687 */ 688 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 689 { 690 ext4_fsblk_t desc_count; 691 struct ext4_group_desc *gdp; 692 ext4_group_t i; 693 ext4_group_t ngroups = ext4_get_groups_count(sb); 694 struct ext4_group_info *grp; 695 #ifdef EXT4FS_DEBUG 696 struct ext4_super_block *es; 697 ext4_fsblk_t bitmap_count; 698 unsigned int x; 699 struct buffer_head *bitmap_bh = NULL; 700 701 es = EXT4_SB(sb)->s_es; 702 desc_count = 0; 703 bitmap_count = 0; 704 gdp = NULL; 705 706 for (i = 0; i < ngroups; i++) { 707 gdp = ext4_get_group_desc(sb, i, NULL); 708 if (!gdp) 709 continue; 710 grp = NULL; 711 if (EXT4_SB(sb)->s_group_info) 712 grp = ext4_get_group_info(sb, i); 713 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 714 desc_count += ext4_free_group_clusters(sb, gdp); 715 brelse(bitmap_bh); 716 bitmap_bh = ext4_read_block_bitmap(sb, i); 717 if (IS_ERR(bitmap_bh)) { 718 bitmap_bh = NULL; 719 continue; 720 } 721 722 x = ext4_count_free(bitmap_bh->b_data, 723 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 724 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 725 i, ext4_free_group_clusters(sb, gdp), x); 726 bitmap_count += x; 727 } 728 brelse(bitmap_bh); 729 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 730 ", computed = %llu, %llu\n", 731 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 732 desc_count, bitmap_count); 733 return bitmap_count; 734 #else 735 desc_count = 0; 736 for (i = 0; i < ngroups; i++) { 737 gdp = ext4_get_group_desc(sb, i, NULL); 738 if (!gdp) 739 continue; 740 grp = NULL; 741 if (EXT4_SB(sb)->s_group_info) 742 grp = ext4_get_group_info(sb, i); 743 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 744 desc_count += ext4_free_group_clusters(sb, gdp); 745 } 746 747 return desc_count; 748 #endif 749 } 750 751 static inline int test_root(ext4_group_t a, int b) 752 { 753 while (1) { 754 if (a < b) 755 return 0; 756 if (a == b) 757 return 1; 758 if ((a % b) != 0) 759 return 0; 760 a = a / b; 761 } 762 } 763 764 /** 765 * ext4_bg_has_super - number of blocks used by the superblock in group 766 * @sb: superblock for filesystem 767 * @group: group number to check 768 * 769 * Return the number of blocks used by the superblock (primary or backup) 770 * in this group. Currently this will be only 0 or 1. 771 */ 772 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 773 { 774 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 775 776 if (group == 0) 777 return 1; 778 if (ext4_has_feature_sparse_super2(sb)) { 779 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 780 group == le32_to_cpu(es->s_backup_bgs[1])) 781 return 1; 782 return 0; 783 } 784 if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) 785 return 1; 786 if (!(group & 1)) 787 return 0; 788 if (test_root(group, 3) || (test_root(group, 5)) || 789 test_root(group, 7)) 790 return 1; 791 792 return 0; 793 } 794 795 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 796 ext4_group_t group) 797 { 798 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 799 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 800 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 801 802 if (group == first || group == first + 1 || group == last) 803 return 1; 804 return 0; 805 } 806 807 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 808 ext4_group_t group) 809 { 810 if (!ext4_bg_has_super(sb, group)) 811 return 0; 812 813 if (ext4_has_feature_meta_bg(sb)) 814 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 815 else 816 return EXT4_SB(sb)->s_gdb_count; 817 } 818 819 /** 820 * ext4_bg_num_gdb - number of blocks used by the group table in group 821 * @sb: superblock for filesystem 822 * @group: group number to check 823 * 824 * Return the number of blocks used by the group descriptor table 825 * (primary or backup) in this group. In the future there may be a 826 * different number of descriptor blocks in each group. 827 */ 828 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 829 { 830 unsigned long first_meta_bg = 831 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 832 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 833 834 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) 835 return ext4_bg_num_gdb_nometa(sb, group); 836 837 return ext4_bg_num_gdb_meta(sb,group); 838 839 } 840 841 /* 842 * This function returns the number of file system metadata clusters at 843 * the beginning of a block group, including the reserved gdt blocks. 844 */ 845 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 846 ext4_group_t block_group) 847 { 848 struct ext4_sb_info *sbi = EXT4_SB(sb); 849 unsigned num; 850 851 /* Check for superblock and gdt backups in this group */ 852 num = ext4_bg_has_super(sb, block_group); 853 854 if (!ext4_has_feature_meta_bg(sb) || 855 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 856 sbi->s_desc_per_block) { 857 if (num) { 858 num += ext4_bg_num_gdb(sb, block_group); 859 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 860 } 861 } else { /* For META_BG_BLOCK_GROUPS */ 862 num += ext4_bg_num_gdb(sb, block_group); 863 } 864 return EXT4_NUM_B2C(sbi, num); 865 } 866 /** 867 * ext4_inode_to_goal_block - return a hint for block allocation 868 * @inode: inode for block allocation 869 * 870 * Return the ideal location to start allocating blocks for a 871 * newly created inode. 872 */ 873 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 874 { 875 struct ext4_inode_info *ei = EXT4_I(inode); 876 ext4_group_t block_group; 877 ext4_grpblk_t colour; 878 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 879 ext4_fsblk_t bg_start; 880 ext4_fsblk_t last_block; 881 882 block_group = ei->i_block_group; 883 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 884 /* 885 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 886 * block groups per flexgroup, reserve the first block 887 * group for directories and special files. Regular 888 * files will start at the second block group. This 889 * tends to speed up directory access and improves 890 * fsck times. 891 */ 892 block_group &= ~(flex_size-1); 893 if (S_ISREG(inode->i_mode)) 894 block_group++; 895 } 896 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 897 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 898 899 /* 900 * If we are doing delayed allocation, we don't need take 901 * colour into account. 902 */ 903 if (test_opt(inode->i_sb, DELALLOC)) 904 return bg_start; 905 906 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 907 colour = (current->pid % 16) * 908 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 909 else 910 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 911 return bg_start + colour; 912 } 913 914