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#include <kunit/static_stub.h> 26 27static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 28 ext4_group_t block_group); 29/* 30 * balloc.c contains the blocks allocation and deallocation routines 31 */ 32 33/* 34 * Calculate block group number for a given block number 35 */ 36ext4_group_t ext4_get_group_number(struct super_block *sb, 37 ext4_fsblk_t block) 38{ 39 ext4_group_t group; 40 41 if (test_opt2(sb, STD_GROUP_SIZE)) 42 group = (block - 43 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >> 44 (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3); 45 else 46 ext4_get_group_no_and_offset(sb, block, &group, NULL); 47 return group; 48} 49 50/* 51 * Calculate the block group number and offset into the block/cluster 52 * allocation bitmap, given a block number 53 */ 54void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, 55 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) 56{ 57 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 58 ext4_grpblk_t offset; 59 60 blocknr = blocknr - le32_to_cpu(es->s_first_data_block); 61 offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> 62 EXT4_SB(sb)->s_cluster_bits; 63 if (offsetp) 64 *offsetp = offset; 65 if (blockgrpp) 66 *blockgrpp = blocknr; 67 68} 69 70/* 71 * Check whether the 'block' lives within the 'block_group'. Returns 1 if so 72 * and 0 otherwise. 73 */ 74static inline int ext4_block_in_group(struct super_block *sb, 75 ext4_fsblk_t block, 76 ext4_group_t block_group) 77{ 78 ext4_group_t actual_group; 79 80 actual_group = ext4_get_group_number(sb, block); 81 return (actual_group == block_group) ? 1 : 0; 82} 83 84/* 85 * Return the number of clusters used for file system metadata; this 86 * represents the overhead needed by the file system. 87 */ 88static unsigned ext4_num_overhead_clusters(struct super_block *sb, 89 ext4_group_t block_group, 90 struct ext4_group_desc *gdp) 91{ 92 unsigned base_clusters, num_clusters; 93 int block_cluster = -1, inode_cluster; 94 int itbl_cluster_start = -1, itbl_cluster_end = -1; 95 ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); 96 ext4_fsblk_t end = start + EXT4_BLOCKS_PER_GROUP(sb) - 1; 97 ext4_fsblk_t itbl_blk_start, itbl_blk_end; 98 struct ext4_sb_info *sbi = EXT4_SB(sb); 99 100 /* This is the number of clusters used by the superblock, 101 * block group descriptors, and reserved block group 102 * descriptor blocks */ 103 base_clusters = ext4_num_base_meta_clusters(sb, block_group); 104 num_clusters = base_clusters; 105 106 /* 107 * Account and record inode table clusters if any cluster 108 * is in the block group, or inode table cluster range is 109 * [-1, -1] and won't overlap with block/inode bitmap cluster 110 * accounted below. 111 */ 112 itbl_blk_start = ext4_inode_table(sb, gdp); 113 itbl_blk_end = itbl_blk_start + sbi->s_itb_per_group - 1; 114 if (itbl_blk_start <= end && itbl_blk_end >= start) { 115 itbl_blk_start = max(itbl_blk_start, start); 116 itbl_blk_end = min(itbl_blk_end, end); 117 118 itbl_cluster_start = EXT4_B2C(sbi, itbl_blk_start - start); 119 itbl_cluster_end = EXT4_B2C(sbi, itbl_blk_end - start); 120 121 num_clusters += itbl_cluster_end - itbl_cluster_start + 1; 122 /* check if border cluster is overlapped */ 123 if (itbl_cluster_start == base_clusters - 1) 124 num_clusters--; 125 } 126 127 /* 128 * For the allocation bitmaps, we first need to check to see 129 * if the block is in the block group. If it is, then check 130 * to see if the cluster is already accounted for in the clusters 131 * used for the base metadata cluster and inode tables cluster. 132 * Normally all of these blocks are contiguous, so the special 133 * case handling shouldn't be necessary except for *very* 134 * unusual file system layouts. 135 */ 136 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { 137 block_cluster = EXT4_B2C(sbi, 138 ext4_block_bitmap(sb, gdp) - start); 139 if (block_cluster >= base_clusters && 140 (block_cluster < itbl_cluster_start || 141 block_cluster > itbl_cluster_end)) 142 num_clusters++; 143 } 144 145 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { 146 inode_cluster = EXT4_B2C(sbi, 147 ext4_inode_bitmap(sb, gdp) - start); 148 /* 149 * Additional check if inode bitmap is in just accounted 150 * block_cluster 151 */ 152 if (inode_cluster != block_cluster && 153 inode_cluster >= base_clusters && 154 (inode_cluster < itbl_cluster_start || 155 inode_cluster > itbl_cluster_end)) 156 num_clusters++; 157 } 158 159 return num_clusters; 160} 161 162static unsigned int num_clusters_in_group(struct super_block *sb, 163 ext4_group_t block_group) 164{ 165 unsigned int blocks; 166 167 if (block_group == ext4_get_groups_count(sb) - 1) { 168 /* 169 * Even though mke2fs always initializes the first and 170 * last group, just in case some other tool was used, 171 * we need to make sure we calculate the right free 172 * blocks. 173 */ 174 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - 175 ext4_group_first_block_no(sb, block_group); 176 } else 177 blocks = EXT4_BLOCKS_PER_GROUP(sb); 178 return EXT4_NUM_B2C(EXT4_SB(sb), blocks); 179} 180 181/* Initializes an uninitialized block bitmap */ 182static int ext4_init_block_bitmap(struct super_block *sb, 183 struct buffer_head *bh, 184 ext4_group_t block_group, 185 struct ext4_group_desc *gdp) 186{ 187 unsigned int bit, bit_max; 188 struct ext4_sb_info *sbi = EXT4_SB(sb); 189 ext4_fsblk_t start, tmp; 190 191 ASSERT(buffer_locked(bh)); 192 193 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 /* Set bits for block and inode bitmaps, and inode table */ 211 tmp = ext4_block_bitmap(sb, gdp); 212 if (ext4_block_in_group(sb, tmp, block_group)) 213 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 214 215 tmp = ext4_inode_bitmap(sb, gdp); 216 if (ext4_block_in_group(sb, tmp, block_group)) 217 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 218 219 tmp = ext4_inode_table(sb, gdp); 220 for (; tmp < ext4_inode_table(sb, gdp) + 221 sbi->s_itb_per_group; tmp++) { 222 if (ext4_block_in_group(sb, tmp, block_group)) 223 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 224 } 225 226 /* 227 * Also if the number of blocks within the group is less than 228 * the blocksize * 8 ( which is the size of bitmap ), set rest 229 * of the block bitmap to 1 230 */ 231 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), 232 sb->s_blocksize * 8, bh->b_data); 233 return 0; 234} 235 236/* Return the number of free blocks in a block group. It is used when 237 * the block bitmap is uninitialized, so we can't just count the bits 238 * in the bitmap. */ 239unsigned ext4_free_clusters_after_init(struct super_block *sb, 240 ext4_group_t block_group, 241 struct ext4_group_desc *gdp) 242{ 243 return num_clusters_in_group(sb, block_group) - 244 ext4_num_overhead_clusters(sb, block_group, gdp); 245} 246 247/* 248 * The free blocks are managed by bitmaps. A file system contains several 249 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 250 * block for inodes, N blocks for the inode table and data blocks. 251 * 252 * The file system contains group descriptors which are located after the 253 * super block. Each descriptor contains the number of the bitmap block and 254 * the free blocks count in the block. The descriptors are loaded in memory 255 * when a file system is mounted (see ext4_fill_super). 256 */ 257 258/** 259 * ext4_get_group_desc() -- load group descriptor from disk 260 * @sb: super block 261 * @block_group: given block group 262 * @bh: pointer to the buffer head to store the block 263 * group descriptor 264 */ 265struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, 266 ext4_group_t block_group, 267 struct buffer_head **bh) 268{ 269 unsigned int group_desc; 270 unsigned int offset; 271 ext4_group_t ngroups = ext4_get_groups_count(sb); 272 struct ext4_group_desc *desc; 273 struct ext4_sb_info *sbi = EXT4_SB(sb); 274 struct buffer_head *bh_p; 275 276 KUNIT_STATIC_STUB_REDIRECT(ext4_get_group_desc, 277 sb, block_group, bh); 278 279 if (block_group >= ngroups) { 280 ext4_error(sb, "block_group >= groups_count - block_group = %u," 281 " groups_count = %u", block_group, ngroups); 282 283 return NULL; 284 } 285 286 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 287 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 288 bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc); 289 /* 290 * sbi_array_rcu_deref returns with rcu unlocked, this is ok since 291 * the pointer being dereferenced won't be dereferenced again. By 292 * looking at the usage in add_new_gdb() the value isn't modified, 293 * just the pointer, and so it remains valid. 294 */ 295 if (!bh_p) { 296 ext4_error(sb, "Group descriptor not loaded - " 297 "block_group = %u, group_desc = %u, desc = %u", 298 block_group, group_desc, offset); 299 return NULL; 300 } 301 302 desc = (struct ext4_group_desc *)( 303 (__u8 *)bh_p->b_data + 304 offset * EXT4_DESC_SIZE(sb)); 305 if (bh) 306 *bh = bh_p; 307 return desc; 308} 309 310static ext4_fsblk_t ext4_valid_block_bitmap_padding(struct super_block *sb, 311 ext4_group_t block_group, 312 struct buffer_head *bh) 313{ 314 ext4_grpblk_t next_zero_bit; 315 unsigned long bitmap_size = sb->s_blocksize * 8; 316 unsigned int offset = num_clusters_in_group(sb, block_group); 317 318 if (bitmap_size <= offset) 319 return 0; 320 321 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, bitmap_size, offset); 322 323 return (next_zero_bit < bitmap_size ? next_zero_bit : 0); 324} 325 326struct ext4_group_info *ext4_get_group_info(struct super_block *sb, 327 ext4_group_t group) 328{ 329 struct ext4_group_info **grp_info; 330 long indexv, indexh; 331 332 if (unlikely(group >= EXT4_SB(sb)->s_groups_count)) 333 return NULL; 334 indexv = group >> (EXT4_DESC_PER_BLOCK_BITS(sb)); 335 indexh = group & ((EXT4_DESC_PER_BLOCK(sb)) - 1); 336 grp_info = sbi_array_rcu_deref(EXT4_SB(sb), s_group_info, indexv); 337 return grp_info[indexh]; 338} 339 340/* 341 * Return the block number which was discovered to be invalid, or 0 if 342 * the block bitmap is valid. 343 */ 344static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, 345 struct ext4_group_desc *desc, 346 ext4_group_t block_group, 347 struct buffer_head *bh) 348{ 349 struct ext4_sb_info *sbi = EXT4_SB(sb); 350 ext4_grpblk_t offset; 351 ext4_grpblk_t next_zero_bit; 352 ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); 353 ext4_fsblk_t blk; 354 ext4_fsblk_t group_first_block; 355 356 if (ext4_has_feature_flex_bg(sb)) { 357 /* with FLEX_BG, the inode/block bitmaps and itable 358 * blocks may not be in the group at all 359 * so the bitmap validation will be skipped for those groups 360 * or it has to also read the block group where the bitmaps 361 * are located to verify they are set. 362 */ 363 return 0; 364 } 365 group_first_block = ext4_group_first_block_no(sb, block_group); 366 367 /* check whether block bitmap block number is set */ 368 blk = ext4_block_bitmap(sb, desc); 369 offset = blk - group_first_block; 370 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 371 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 372 /* bad block bitmap */ 373 return blk; 374 375 /* check whether the inode bitmap block number is set */ 376 blk = ext4_inode_bitmap(sb, desc); 377 offset = blk - group_first_block; 378 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 379 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 380 /* bad block bitmap */ 381 return blk; 382 383 /* check whether the inode table block number is set */ 384 blk = ext4_inode_table(sb, desc); 385 offset = blk - group_first_block; 386 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 387 EXT4_B2C(sbi, offset + sbi->s_itb_per_group - 1) >= max_bit) 388 return blk; 389 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 390 EXT4_B2C(sbi, offset + sbi->s_itb_per_group - 1) + 1, 391 EXT4_B2C(sbi, offset)); 392 if (next_zero_bit < 393 EXT4_B2C(sbi, offset + sbi->s_itb_per_group - 1) + 1) 394 /* bad bitmap for inode tables */ 395 return blk; 396 return 0; 397} 398 399static int ext4_validate_block_bitmap(struct super_block *sb, 400 struct ext4_group_desc *desc, 401 ext4_group_t block_group, 402 struct buffer_head *bh) 403{ 404 ext4_fsblk_t blk; 405 struct ext4_group_info *grp; 406 407 if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) 408 return 0; 409 410 grp = ext4_get_group_info(sb, block_group); 411 412 if (buffer_verified(bh)) 413 return 0; 414 if (!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 415 return -EFSCORRUPTED; 416 417 ext4_lock_group(sb, block_group); 418 if (buffer_verified(bh)) 419 goto verified; 420 if (unlikely(!ext4_block_bitmap_csum_verify(sb, desc, bh) || 421 ext4_simulate_fail(sb, EXT4_SIM_BBITMAP_CRC))) { 422 ext4_unlock_group(sb, block_group); 423 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 424 ext4_mark_group_bitmap_corrupted(sb, block_group, 425 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 426 return -EFSBADCRC; 427 } 428 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 429 if (unlikely(blk != 0)) { 430 ext4_unlock_group(sb, block_group); 431 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 432 block_group, blk); 433 ext4_mark_group_bitmap_corrupted(sb, block_group, 434 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 435 return -EFSCORRUPTED; 436 } 437 blk = ext4_valid_block_bitmap_padding(sb, block_group, bh); 438 if (unlikely(blk != 0)) { 439 ext4_unlock_group(sb, block_group); 440 ext4_error(sb, "bg %u: block %llu: padding at end of block bitmap is not set", 441 block_group, blk); 442 ext4_mark_group_bitmap_corrupted(sb, block_group, 443 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 444 return -EFSCORRUPTED; 445 } 446 set_buffer_verified(bh); 447verified: 448 ext4_unlock_group(sb, block_group); 449 return 0; 450} 451 452/** 453 * ext4_read_block_bitmap_nowait() 454 * @sb: super block 455 * @block_group: given block group 456 * @ignore_locked: ignore locked buffers 457 * 458 * Read the bitmap for a given block_group,and validate the 459 * bits for block/inode/inode tables are set in the bitmaps 460 * 461 * Return buffer_head on success or an ERR_PTR in case of failure. 462 */ 463struct buffer_head * 464ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group, 465 bool ignore_locked) 466{ 467 struct ext4_group_desc *desc; 468 struct ext4_sb_info *sbi = EXT4_SB(sb); 469 struct buffer_head *bh; 470 ext4_fsblk_t bitmap_blk; 471 int err; 472 473 KUNIT_STATIC_STUB_REDIRECT(ext4_read_block_bitmap_nowait, 474 sb, block_group, ignore_locked); 475 476 desc = ext4_get_group_desc(sb, block_group, NULL); 477 if (!desc) 478 return ERR_PTR(-EFSCORRUPTED); 479 bitmap_blk = ext4_block_bitmap(sb, desc); 480 if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || 481 (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { 482 ext4_error(sb, "Invalid block bitmap block %llu in " 483 "block_group %u", bitmap_blk, block_group); 484 ext4_mark_group_bitmap_corrupted(sb, block_group, 485 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 486 return ERR_PTR(-EFSCORRUPTED); 487 } 488 bh = sb_getblk(sb, bitmap_blk); 489 if (unlikely(!bh)) { 490 ext4_warning(sb, "Cannot get buffer for block bitmap - " 491 "block_group = %u, block_bitmap = %llu", 492 block_group, bitmap_blk); 493 return ERR_PTR(-ENOMEM); 494 } 495 496 if (ignore_locked && buffer_locked(bh)) { 497 /* buffer under IO already, return if called for prefetching */ 498 put_bh(bh); 499 return NULL; 500 } 501 502 if (bitmap_uptodate(bh)) 503 goto verify; 504 505 lock_buffer(bh); 506 if (bitmap_uptodate(bh)) { 507 unlock_buffer(bh); 508 goto verify; 509 } 510 ext4_lock_group(sb, block_group); 511 if (ext4_has_group_desc_csum(sb) && 512 (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { 513 if (block_group == 0) { 514 ext4_unlock_group(sb, block_group); 515 unlock_buffer(bh); 516 ext4_error(sb, "Block bitmap for bg 0 marked " 517 "uninitialized"); 518 err = -EFSCORRUPTED; 519 goto out; 520 } 521 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 522 if (err) { 523 ext4_unlock_group(sb, block_group); 524 unlock_buffer(bh); 525 ext4_error(sb, "Failed to init block bitmap for group " 526 "%u: %d", block_group, err); 527 goto out; 528 } 529 set_bitmap_uptodate(bh); 530 set_buffer_uptodate(bh); 531 set_buffer_verified(bh); 532 ext4_unlock_group(sb, block_group); 533 unlock_buffer(bh); 534 return bh; 535 } 536 ext4_unlock_group(sb, block_group); 537 if (buffer_uptodate(bh)) { 538 /* 539 * if not uninit if bh is uptodate, 540 * bitmap is also uptodate 541 */ 542 set_bitmap_uptodate(bh); 543 unlock_buffer(bh); 544 goto verify; 545 } 546 /* 547 * submit the buffer_head for reading 548 */ 549 set_buffer_new(bh); 550 trace_ext4_read_block_bitmap_load(sb, block_group, ignore_locked); 551 ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO | 552 (ignore_locked ? REQ_RAHEAD : 0), 553 ext4_end_bitmap_read); 554 return bh; 555verify: 556 err = ext4_validate_block_bitmap(sb, desc, block_group, bh); 557 if (err) 558 goto out; 559 return bh; 560out: 561 put_bh(bh); 562 return ERR_PTR(err); 563} 564 565/* Returns 0 on success, -errno on error */ 566int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 567 struct buffer_head *bh) 568{ 569 struct ext4_group_desc *desc; 570 571 KUNIT_STATIC_STUB_REDIRECT(ext4_wait_block_bitmap, 572 sb, block_group, bh); 573 574 if (!buffer_new(bh)) 575 return 0; 576 desc = ext4_get_group_desc(sb, block_group, NULL); 577 if (!desc) 578 return -EFSCORRUPTED; 579 wait_on_buffer(bh); 580 ext4_simulate_fail_bh(sb, bh, EXT4_SIM_BBITMAP_EIO); 581 if (!buffer_uptodate(bh)) { 582 ext4_error_err(sb, EIO, "Cannot read block bitmap - " 583 "block_group = %u, block_bitmap = %llu", 584 block_group, (unsigned long long) bh->b_blocknr); 585 ext4_mark_group_bitmap_corrupted(sb, block_group, 586 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 587 return -EIO; 588 } 589 clear_buffer_new(bh); 590 /* Panic or remount fs read-only if block bitmap is invalid */ 591 return ext4_validate_block_bitmap(sb, desc, block_group, bh); 592} 593 594struct buffer_head * 595ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 596{ 597 struct buffer_head *bh; 598 int err; 599 600 bh = ext4_read_block_bitmap_nowait(sb, block_group, false); 601 if (IS_ERR(bh)) 602 return bh; 603 err = ext4_wait_block_bitmap(sb, block_group, bh); 604 if (err) { 605 put_bh(bh); 606 return ERR_PTR(err); 607 } 608 return bh; 609} 610 611/** 612 * ext4_has_free_clusters() 613 * @sbi: in-core super block structure. 614 * @nclusters: number of needed blocks 615 * @flags: flags from ext4_mb_new_blocks() 616 * 617 * Check if filesystem has nclusters free & available for allocation. 618 * On success return 1, return 0 on failure. 619 */ 620static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 621 s64 nclusters, unsigned int flags) 622{ 623 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 624 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 625 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 626 627 free_clusters = percpu_counter_read_positive(fcc); 628 dirty_clusters = percpu_counter_read_positive(dcc); 629 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 630 631 /* 632 * r_blocks_count should always be multiple of the cluster ratio so 633 * we are safe to do a plane bit shift only. 634 */ 635 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 636 resv_clusters; 637 638 if (free_clusters - (nclusters + rsv + dirty_clusters) < 639 EXT4_FREECLUSTERS_WATERMARK) { 640 free_clusters = percpu_counter_sum_positive(fcc); 641 dirty_clusters = percpu_counter_sum_positive(dcc); 642 } 643 /* Check whether we have space after accounting for current 644 * dirty clusters & root reserved clusters. 645 */ 646 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 647 return 1; 648 649 /* Hm, nope. Are (enough) root reserved clusters available? */ 650 if (uid_eq(sbi->s_resuid, current_fsuid()) || 651 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 652 capable(CAP_SYS_RESOURCE) || 653 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 654 655 if (free_clusters >= (nclusters + dirty_clusters + 656 resv_clusters)) 657 return 1; 658 } 659 /* No free blocks. Let's see if we can dip into reserved pool */ 660 if (flags & EXT4_MB_USE_RESERVED) { 661 if (free_clusters >= (nclusters + dirty_clusters)) 662 return 1; 663 } 664 665 return 0; 666} 667 668int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 669 s64 nclusters, unsigned int flags) 670{ 671 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 672 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 673 return 0; 674 } else 675 return -ENOSPC; 676} 677 678/** 679 * ext4_should_retry_alloc() - check if a block allocation should be retried 680 * @sb: superblock 681 * @retries: number of retry attempts made so far 682 * 683 * ext4_should_retry_alloc() is called when ENOSPC is returned while 684 * attempting to allocate blocks. If there's an indication that a pending 685 * journal transaction might free some space and allow another attempt to 686 * succeed, this function will wait for the current or committing transaction 687 * to complete and then return TRUE. 688 */ 689int ext4_should_retry_alloc(struct super_block *sb, int *retries) 690{ 691 struct ext4_sb_info *sbi = EXT4_SB(sb); 692 693 if (!sbi->s_journal) 694 return 0; 695 696 if (++(*retries) > 3) { 697 percpu_counter_inc(&sbi->s_sra_exceeded_retry_limit); 698 return 0; 699 } 700 701 /* 702 * if there's no indication that blocks are about to be freed it's 703 * possible we just missed a transaction commit that did so 704 */ 705 smp_mb(); 706 if (sbi->s_mb_free_pending == 0) { 707 if (test_opt(sb, DISCARD)) { 708 atomic_inc(&sbi->s_retry_alloc_pending); 709 flush_work(&sbi->s_discard_work); 710 atomic_dec(&sbi->s_retry_alloc_pending); 711 } 712 return ext4_has_free_clusters(sbi, 1, 0); 713 } 714 715 /* 716 * it's possible we've just missed a transaction commit here, 717 * so ignore the returned status 718 */ 719 ext4_debug("%s: retrying operation after ENOSPC\n", sb->s_id); 720 (void) jbd2_journal_force_commit_nested(sbi->s_journal); 721 return 1; 722} 723 724/* 725 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 726 * 727 * @handle: handle to this transaction 728 * @inode: file inode 729 * @goal: given target block(filesystem wide) 730 * @count: pointer to total number of clusters needed 731 * @errp: error code 732 * 733 * Return 1st allocated block number on success, *count stores total account 734 * error stores in errp pointer 735 */ 736ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 737 ext4_fsblk_t goal, unsigned int flags, 738 unsigned long *count, int *errp) 739{ 740 struct ext4_allocation_request ar; 741 ext4_fsblk_t ret; 742 743 memset(&ar, 0, sizeof(ar)); 744 /* Fill with neighbour allocated blocks */ 745 ar.inode = inode; 746 ar.goal = goal; 747 ar.len = count ? *count : 1; 748 ar.flags = flags; 749 750 ret = ext4_mb_new_blocks(handle, &ar, errp); 751 if (count) 752 *count = ar.len; 753 /* 754 * Account for the allocated meta blocks. We will never 755 * fail EDQUOT for metdata, but we do account for it. 756 */ 757 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 758 dquot_alloc_block_nofail(inode, 759 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 760 } 761 return ret; 762} 763 764/** 765 * ext4_count_free_clusters() -- count filesystem free clusters 766 * @sb: superblock 767 * 768 * Adds up the number of free clusters from each block group. 769 */ 770ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 771{ 772 ext4_fsblk_t desc_count; 773 struct ext4_group_desc *gdp; 774 ext4_group_t i; 775 ext4_group_t ngroups = ext4_get_groups_count(sb); 776 struct ext4_group_info *grp; 777#ifdef EXT4FS_DEBUG 778 struct ext4_super_block *es; 779 ext4_fsblk_t bitmap_count; 780 unsigned int x; 781 struct buffer_head *bitmap_bh = NULL; 782 783 es = EXT4_SB(sb)->s_es; 784 desc_count = 0; 785 bitmap_count = 0; 786 gdp = NULL; 787 788 for (i = 0; i < ngroups; i++) { 789 gdp = ext4_get_group_desc(sb, i, NULL); 790 if (!gdp) 791 continue; 792 grp = NULL; 793 if (EXT4_SB(sb)->s_group_info) 794 grp = ext4_get_group_info(sb, i); 795 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 796 desc_count += ext4_free_group_clusters(sb, gdp); 797 brelse(bitmap_bh); 798 bitmap_bh = ext4_read_block_bitmap(sb, i); 799 if (IS_ERR(bitmap_bh)) { 800 bitmap_bh = NULL; 801 continue; 802 } 803 804 x = ext4_count_free(bitmap_bh->b_data, 805 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 806 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 807 i, ext4_free_group_clusters(sb, gdp), x); 808 bitmap_count += x; 809 } 810 brelse(bitmap_bh); 811 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 812 ", computed = %llu, %llu\n", 813 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 814 desc_count, bitmap_count); 815 return bitmap_count; 816#else 817 desc_count = 0; 818 for (i = 0; i < ngroups; i++) { 819 gdp = ext4_get_group_desc(sb, i, NULL); 820 if (!gdp) 821 continue; 822 grp = NULL; 823 if (EXT4_SB(sb)->s_group_info) 824 grp = ext4_get_group_info(sb, i); 825 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 826 desc_count += ext4_free_group_clusters(sb, gdp); 827 } 828 829 return desc_count; 830#endif 831} 832 833static inline int test_root(ext4_group_t a, int b) 834{ 835 while (1) { 836 if (a < b) 837 return 0; 838 if (a == b) 839 return 1; 840 if ((a % b) != 0) 841 return 0; 842 a = a / b; 843 } 844} 845 846/** 847 * ext4_bg_has_super - number of blocks used by the superblock in group 848 * @sb: superblock for filesystem 849 * @group: group number to check 850 * 851 * Return the number of blocks used by the superblock (primary or backup) 852 * in this group. Currently this will be only 0 or 1. 853 */ 854int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 855{ 856 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 857 858 if (group == 0) 859 return 1; 860 if (ext4_has_feature_sparse_super2(sb)) { 861 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 862 group == le32_to_cpu(es->s_backup_bgs[1])) 863 return 1; 864 return 0; 865 } 866 if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) 867 return 1; 868 if (!(group & 1)) 869 return 0; 870 if (test_root(group, 3) || (test_root(group, 5)) || 871 test_root(group, 7)) 872 return 1; 873 874 return 0; 875} 876 877static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 878 ext4_group_t group) 879{ 880 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 881 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 882 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 883 884 if (group == first || group == first + 1 || group == last) 885 return 1; 886 return 0; 887} 888 889static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 890 ext4_group_t group) 891{ 892 if (!ext4_bg_has_super(sb, group)) 893 return 0; 894 895 if (ext4_has_feature_meta_bg(sb)) 896 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 897 else 898 return EXT4_SB(sb)->s_gdb_count; 899} 900 901/** 902 * ext4_bg_num_gdb - number of blocks used by the group table in group 903 * @sb: superblock for filesystem 904 * @group: group number to check 905 * 906 * Return the number of blocks used by the group descriptor table 907 * (primary or backup) in this group. In the future there may be a 908 * different number of descriptor blocks in each group. 909 */ 910unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 911{ 912 unsigned long first_meta_bg = 913 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 914 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 915 916 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) 917 return ext4_bg_num_gdb_nometa(sb, group); 918 919 return ext4_bg_num_gdb_meta(sb,group); 920 921} 922 923/* 924 * This function returns the number of file system metadata blocks at 925 * the beginning of a block group, including the reserved gdt blocks. 926 */ 927unsigned int ext4_num_base_meta_blocks(struct super_block *sb, 928 ext4_group_t block_group) 929{ 930 struct ext4_sb_info *sbi = EXT4_SB(sb); 931 unsigned num; 932 933 /* Check for superblock and gdt backups in this group */ 934 num = ext4_bg_has_super(sb, block_group); 935 936 if (!ext4_has_feature_meta_bg(sb) || 937 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 938 sbi->s_desc_per_block) { 939 if (num) { 940 num += ext4_bg_num_gdb_nometa(sb, block_group); 941 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 942 } 943 } else { /* For META_BG_BLOCK_GROUPS */ 944 num += ext4_bg_num_gdb_meta(sb, block_group); 945 } 946 return num; 947} 948 949static unsigned int ext4_num_base_meta_clusters(struct super_block *sb, 950 ext4_group_t block_group) 951{ 952 return EXT4_NUM_B2C(EXT4_SB(sb), ext4_num_base_meta_blocks(sb, block_group)); 953} 954 955/** 956 * ext4_inode_to_goal_block - return a hint for block allocation 957 * @inode: inode for block allocation 958 * 959 * Return the ideal location to start allocating blocks for a 960 * newly created inode. 961 */ 962ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 963{ 964 struct ext4_inode_info *ei = EXT4_I(inode); 965 ext4_group_t block_group; 966 ext4_grpblk_t colour; 967 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 968 ext4_fsblk_t bg_start; 969 ext4_fsblk_t last_block; 970 971 block_group = ei->i_block_group; 972 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 973 /* 974 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 975 * block groups per flexgroup, reserve the first block 976 * group for directories and special files. Regular 977 * files will start at the second block group. This 978 * tends to speed up directory access and improves 979 * fsck times. 980 */ 981 block_group &= ~(flex_size-1); 982 if (S_ISREG(inode->i_mode)) 983 block_group++; 984 } 985 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 986 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 987 988 /* 989 * If we are doing delayed allocation, we don't need take 990 * colour into account. 991 */ 992 if (test_opt(inode->i_sb, DELALLOC)) 993 return bg_start; 994 995 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 996 colour = (task_pid_nr(current) % 16) * 997 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 998 else 999 colour = (task_pid_nr(current) % 16) * 1000 ((last_block - bg_start) / 16); 1001 return bg_start + colour; 1002} 1003 1004