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 /* 84 * Return the number of clusters used for file system metadata; this 85 * represents the overhead needed by the file system. 86 */ 87 static unsigned ext4_num_overhead_clusters(struct super_block *sb, 88 ext4_group_t block_group, 89 struct ext4_group_desc *gdp) 90 { 91 unsigned base_clusters, num_clusters; 92 int block_cluster = -1, inode_cluster; 93 int itbl_cluster_start = -1, itbl_cluster_end = -1; 94 ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); 95 ext4_fsblk_t end = start + EXT4_BLOCKS_PER_GROUP(sb) - 1; 96 ext4_fsblk_t itbl_blk_start, itbl_blk_end; 97 struct ext4_sb_info *sbi = EXT4_SB(sb); 98 99 /* This is the number of clusters used by the superblock, 100 * block group descriptors, and reserved block group 101 * descriptor blocks */ 102 base_clusters = ext4_num_base_meta_clusters(sb, block_group); 103 num_clusters = base_clusters; 104 105 /* 106 * Account and record inode table clusters if any cluster 107 * is in the block group, or inode table cluster range is 108 * [-1, -1] and won't overlap with block/inode bitmap cluster 109 * accounted below. 110 */ 111 itbl_blk_start = ext4_inode_table(sb, gdp); 112 itbl_blk_end = itbl_blk_start + sbi->s_itb_per_group - 1; 113 if (itbl_blk_start <= end && itbl_blk_end >= start) { 114 itbl_blk_start = itbl_blk_start >= start ? 115 itbl_blk_start : start; 116 itbl_blk_end = itbl_blk_end <= end ? 117 itbl_blk_end : end; 118 119 itbl_cluster_start = EXT4_B2C(sbi, itbl_blk_start - start); 120 itbl_cluster_end = EXT4_B2C(sbi, itbl_blk_end - start); 121 122 num_clusters += itbl_cluster_end - itbl_cluster_start + 1; 123 /* check if border cluster is overlapped */ 124 if (itbl_cluster_start == base_clusters - 1) 125 num_clusters--; 126 } 127 128 /* 129 * For the allocation bitmaps, we first need to check to see 130 * if the block is in the block group. If it is, then check 131 * to see if the cluster is already accounted for in the clusters 132 * used for the base metadata cluster and inode tables cluster. 133 * Normally all of these blocks are contiguous, so the special 134 * case handling shouldn't be necessary except for *very* 135 * unusual file system layouts. 136 */ 137 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { 138 block_cluster = EXT4_B2C(sbi, 139 ext4_block_bitmap(sb, gdp) - start); 140 if (block_cluster >= base_clusters && 141 (block_cluster < itbl_cluster_start || 142 block_cluster > itbl_cluster_end)) 143 num_clusters++; 144 } 145 146 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { 147 inode_cluster = EXT4_B2C(sbi, 148 ext4_inode_bitmap(sb, gdp) - start); 149 /* 150 * Additional check if inode bitmap is in just accounted 151 * block_cluster 152 */ 153 if (inode_cluster != block_cluster && 154 inode_cluster >= base_clusters && 155 (inode_cluster < itbl_cluster_start || 156 inode_cluster > itbl_cluster_end)) 157 num_clusters++; 158 } 159 160 return num_clusters; 161 } 162 163 static unsigned int num_clusters_in_group(struct super_block *sb, 164 ext4_group_t block_group) 165 { 166 unsigned int blocks; 167 168 if (block_group == ext4_get_groups_count(sb) - 1) { 169 /* 170 * Even though mke2fs always initializes the first and 171 * last group, just in case some other tool was used, 172 * we need to make sure we calculate the right free 173 * blocks. 174 */ 175 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - 176 ext4_group_first_block_no(sb, block_group); 177 } else 178 blocks = EXT4_BLOCKS_PER_GROUP(sb); 179 return EXT4_NUM_B2C(EXT4_SB(sb), blocks); 180 } 181 182 /* Initializes an uninitialized block bitmap */ 183 static int ext4_init_block_bitmap(struct super_block *sb, 184 struct buffer_head *bh, 185 ext4_group_t block_group, 186 struct ext4_group_desc *gdp) 187 { 188 unsigned int bit, bit_max; 189 struct ext4_sb_info *sbi = EXT4_SB(sb); 190 ext4_fsblk_t start, tmp; 191 192 ASSERT(buffer_locked(bh)); 193 194 if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) { 195 ext4_mark_group_bitmap_corrupted(sb, block_group, 196 EXT4_GROUP_INFO_BBITMAP_CORRUPT | 197 EXT4_GROUP_INFO_IBITMAP_CORRUPT); 198 return -EFSBADCRC; 199 } 200 memset(bh->b_data, 0, sb->s_blocksize); 201 202 bit_max = ext4_num_base_meta_clusters(sb, block_group); 203 if ((bit_max >> 3) >= bh->b_size) 204 return -EFSCORRUPTED; 205 206 for (bit = 0; bit < bit_max; bit++) 207 ext4_set_bit(bit, bh->b_data); 208 209 start = ext4_group_first_block_no(sb, block_group); 210 211 /* Set bits for block and inode bitmaps, and inode table */ 212 tmp = ext4_block_bitmap(sb, gdp); 213 if (ext4_block_in_group(sb, tmp, block_group)) 214 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 215 216 tmp = ext4_inode_bitmap(sb, gdp); 217 if (ext4_block_in_group(sb, tmp, block_group)) 218 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 219 220 tmp = ext4_inode_table(sb, gdp); 221 for (; tmp < ext4_inode_table(sb, gdp) + 222 sbi->s_itb_per_group; tmp++) { 223 if (ext4_block_in_group(sb, tmp, block_group)) 224 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 225 } 226 227 /* 228 * Also if the number of blocks within the group is less than 229 * the blocksize * 8 ( which is the size of bitmap ), set rest 230 * of the block bitmap to 1 231 */ 232 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), 233 sb->s_blocksize * 8, bh->b_data); 234 return 0; 235 } 236 237 /* Return the number of free blocks in a block group. It is used when 238 * the block bitmap is uninitialized, so we can't just count the bits 239 * in the bitmap. */ 240 unsigned ext4_free_clusters_after_init(struct super_block *sb, 241 ext4_group_t block_group, 242 struct ext4_group_desc *gdp) 243 { 244 return num_clusters_in_group(sb, block_group) - 245 ext4_num_overhead_clusters(sb, block_group, gdp); 246 } 247 248 /* 249 * The free blocks are managed by bitmaps. A file system contains several 250 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 251 * block for inodes, N blocks for the inode table and data blocks. 252 * 253 * The file system contains group descriptors which are located after the 254 * super block. Each descriptor contains the number of the bitmap block and 255 * the free blocks count in the block. The descriptors are loaded in memory 256 * when a file system is mounted (see ext4_fill_super). 257 */ 258 259 /** 260 * ext4_get_group_desc() -- load group descriptor from disk 261 * @sb: super block 262 * @block_group: given block group 263 * @bh: pointer to the buffer head to store the block 264 * group descriptor 265 */ 266 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, 267 ext4_group_t block_group, 268 struct buffer_head **bh) 269 { 270 unsigned int group_desc; 271 unsigned int offset; 272 ext4_group_t ngroups = ext4_get_groups_count(sb); 273 struct ext4_group_desc *desc; 274 struct ext4_sb_info *sbi = EXT4_SB(sb); 275 struct buffer_head *bh_p; 276 277 if (block_group >= ngroups) { 278 ext4_error(sb, "block_group >= groups_count - block_group = %u," 279 " groups_count = %u", block_group, ngroups); 280 281 return NULL; 282 } 283 284 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 285 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 286 bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc); 287 /* 288 * sbi_array_rcu_deref returns with rcu unlocked, this is ok since 289 * the pointer being dereferenced won't be dereferenced again. By 290 * looking at the usage in add_new_gdb() the value isn't modified, 291 * just the pointer, and so it remains valid. 292 */ 293 if (!bh_p) { 294 ext4_error(sb, "Group descriptor not loaded - " 295 "block_group = %u, group_desc = %u, desc = %u", 296 block_group, group_desc, offset); 297 return NULL; 298 } 299 300 desc = (struct ext4_group_desc *)( 301 (__u8 *)bh_p->b_data + 302 offset * EXT4_DESC_SIZE(sb)); 303 if (bh) 304 *bh = bh_p; 305 return desc; 306 } 307 308 static ext4_fsblk_t ext4_valid_block_bitmap_padding(struct super_block *sb, 309 ext4_group_t block_group, 310 struct buffer_head *bh) 311 { 312 ext4_grpblk_t next_zero_bit; 313 unsigned long bitmap_size = sb->s_blocksize * 8; 314 unsigned int offset = num_clusters_in_group(sb, block_group); 315 316 if (bitmap_size <= offset) 317 return 0; 318 319 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, bitmap_size, offset); 320 321 return (next_zero_bit < bitmap_size ? next_zero_bit : 0); 322 } 323 324 struct ext4_group_info *ext4_get_group_info(struct super_block *sb, 325 ext4_group_t group) 326 { 327 struct ext4_group_info **grp_info; 328 long indexv, indexh; 329 330 if (unlikely(group >= EXT4_SB(sb)->s_groups_count)) 331 return NULL; 332 indexv = group >> (EXT4_DESC_PER_BLOCK_BITS(sb)); 333 indexh = group & ((EXT4_DESC_PER_BLOCK(sb)) - 1); 334 grp_info = sbi_array_rcu_deref(EXT4_SB(sb), s_group_info, indexv); 335 return grp_info[indexh]; 336 } 337 338 /* 339 * Return the block number which was discovered to be invalid, or 0 if 340 * the block bitmap is valid. 341 */ 342 static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, 343 struct ext4_group_desc *desc, 344 ext4_group_t block_group, 345 struct buffer_head *bh) 346 { 347 struct ext4_sb_info *sbi = EXT4_SB(sb); 348 ext4_grpblk_t offset; 349 ext4_grpblk_t next_zero_bit; 350 ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); 351 ext4_fsblk_t blk; 352 ext4_fsblk_t group_first_block; 353 354 if (ext4_has_feature_flex_bg(sb)) { 355 /* with FLEX_BG, the inode/block bitmaps and itable 356 * blocks may not be in the group at all 357 * so the bitmap validation will be skipped for those groups 358 * or it has to also read the block group where the bitmaps 359 * are located to verify they are set. 360 */ 361 return 0; 362 } 363 group_first_block = ext4_group_first_block_no(sb, block_group); 364 365 /* check whether block bitmap block number is set */ 366 blk = ext4_block_bitmap(sb, desc); 367 offset = blk - group_first_block; 368 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 369 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 370 /* bad block bitmap */ 371 return blk; 372 373 /* check whether the inode bitmap block number is set */ 374 blk = ext4_inode_bitmap(sb, desc); 375 offset = blk - group_first_block; 376 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 377 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 378 /* bad block bitmap */ 379 return blk; 380 381 /* check whether the inode table block number is set */ 382 blk = ext4_inode_table(sb, desc); 383 offset = blk - group_first_block; 384 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 385 EXT4_B2C(sbi, offset + sbi->s_itb_per_group - 1) >= max_bit) 386 return blk; 387 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 388 EXT4_B2C(sbi, offset + sbi->s_itb_per_group - 1) + 1, 389 EXT4_B2C(sbi, offset)); 390 if (next_zero_bit < 391 EXT4_B2C(sbi, offset + sbi->s_itb_per_group - 1) + 1) 392 /* bad bitmap for inode tables */ 393 return blk; 394 return 0; 395 } 396 397 static int ext4_validate_block_bitmap(struct super_block *sb, 398 struct ext4_group_desc *desc, 399 ext4_group_t block_group, 400 struct buffer_head *bh) 401 { 402 ext4_fsblk_t blk; 403 struct ext4_group_info *grp; 404 405 if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) 406 return 0; 407 408 grp = ext4_get_group_info(sb, block_group); 409 410 if (buffer_verified(bh)) 411 return 0; 412 if (!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 413 return -EFSCORRUPTED; 414 415 ext4_lock_group(sb, block_group); 416 if (buffer_verified(bh)) 417 goto verified; 418 if (unlikely(!ext4_block_bitmap_csum_verify(sb, desc, bh) || 419 ext4_simulate_fail(sb, EXT4_SIM_BBITMAP_CRC))) { 420 ext4_unlock_group(sb, block_group); 421 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 422 ext4_mark_group_bitmap_corrupted(sb, block_group, 423 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 424 return -EFSBADCRC; 425 } 426 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 427 if (unlikely(blk != 0)) { 428 ext4_unlock_group(sb, block_group); 429 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 430 block_group, blk); 431 ext4_mark_group_bitmap_corrupted(sb, block_group, 432 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 433 return -EFSCORRUPTED; 434 } 435 blk = ext4_valid_block_bitmap_padding(sb, block_group, bh); 436 if (unlikely(blk != 0)) { 437 ext4_unlock_group(sb, block_group); 438 ext4_error(sb, "bg %u: block %llu: padding at end of block bitmap is not set", 439 block_group, blk); 440 ext4_mark_group_bitmap_corrupted(sb, block_group, 441 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 442 return -EFSCORRUPTED; 443 } 444 set_buffer_verified(bh); 445 verified: 446 ext4_unlock_group(sb, block_group); 447 return 0; 448 } 449 450 /** 451 * ext4_read_block_bitmap_nowait() 452 * @sb: super block 453 * @block_group: given block group 454 * @ignore_locked: ignore locked buffers 455 * 456 * Read the bitmap for a given block_group,and validate the 457 * bits for block/inode/inode tables are set in the bitmaps 458 * 459 * Return buffer_head on success or an ERR_PTR in case of failure. 460 */ 461 struct buffer_head * 462 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group, 463 bool ignore_locked) 464 { 465 struct ext4_group_desc *desc; 466 struct ext4_sb_info *sbi = EXT4_SB(sb); 467 struct buffer_head *bh; 468 ext4_fsblk_t bitmap_blk; 469 int err; 470 471 desc = ext4_get_group_desc(sb, block_group, NULL); 472 if (!desc) 473 return ERR_PTR(-EFSCORRUPTED); 474 bitmap_blk = ext4_block_bitmap(sb, desc); 475 if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || 476 (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { 477 ext4_error(sb, "Invalid block bitmap block %llu in " 478 "block_group %u", bitmap_blk, block_group); 479 ext4_mark_group_bitmap_corrupted(sb, block_group, 480 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 481 return ERR_PTR(-EFSCORRUPTED); 482 } 483 bh = sb_getblk(sb, bitmap_blk); 484 if (unlikely(!bh)) { 485 ext4_warning(sb, "Cannot get buffer for block bitmap - " 486 "block_group = %u, block_bitmap = %llu", 487 block_group, bitmap_blk); 488 return ERR_PTR(-ENOMEM); 489 } 490 491 if (ignore_locked && buffer_locked(bh)) { 492 /* buffer under IO already, return if called for prefetching */ 493 put_bh(bh); 494 return NULL; 495 } 496 497 if (bitmap_uptodate(bh)) 498 goto verify; 499 500 lock_buffer(bh); 501 if (bitmap_uptodate(bh)) { 502 unlock_buffer(bh); 503 goto verify; 504 } 505 ext4_lock_group(sb, block_group); 506 if (ext4_has_group_desc_csum(sb) && 507 (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { 508 if (block_group == 0) { 509 ext4_unlock_group(sb, block_group); 510 unlock_buffer(bh); 511 ext4_error(sb, "Block bitmap for bg 0 marked " 512 "uninitialized"); 513 err = -EFSCORRUPTED; 514 goto out; 515 } 516 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 517 if (err) { 518 ext4_unlock_group(sb, block_group); 519 unlock_buffer(bh); 520 ext4_error(sb, "Failed to init block bitmap for group " 521 "%u: %d", block_group, err); 522 goto out; 523 } 524 set_bitmap_uptodate(bh); 525 set_buffer_uptodate(bh); 526 set_buffer_verified(bh); 527 ext4_unlock_group(sb, block_group); 528 unlock_buffer(bh); 529 return bh; 530 } 531 ext4_unlock_group(sb, block_group); 532 if (buffer_uptodate(bh)) { 533 /* 534 * if not uninit if bh is uptodate, 535 * bitmap is also uptodate 536 */ 537 set_bitmap_uptodate(bh); 538 unlock_buffer(bh); 539 goto verify; 540 } 541 /* 542 * submit the buffer_head for reading 543 */ 544 set_buffer_new(bh); 545 trace_ext4_read_block_bitmap_load(sb, block_group, ignore_locked); 546 ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO | 547 (ignore_locked ? REQ_RAHEAD : 0), 548 ext4_end_bitmap_read); 549 return bh; 550 verify: 551 err = ext4_validate_block_bitmap(sb, desc, block_group, bh); 552 if (err) 553 goto out; 554 return bh; 555 out: 556 put_bh(bh); 557 return ERR_PTR(err); 558 } 559 560 /* Returns 0 on success, -errno on error */ 561 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 562 struct buffer_head *bh) 563 { 564 struct ext4_group_desc *desc; 565 566 if (!buffer_new(bh)) 567 return 0; 568 desc = ext4_get_group_desc(sb, block_group, NULL); 569 if (!desc) 570 return -EFSCORRUPTED; 571 wait_on_buffer(bh); 572 ext4_simulate_fail_bh(sb, bh, EXT4_SIM_BBITMAP_EIO); 573 if (!buffer_uptodate(bh)) { 574 ext4_error_err(sb, EIO, "Cannot read block bitmap - " 575 "block_group = %u, block_bitmap = %llu", 576 block_group, (unsigned long long) bh->b_blocknr); 577 ext4_mark_group_bitmap_corrupted(sb, block_group, 578 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 579 return -EIO; 580 } 581 clear_buffer_new(bh); 582 /* Panic or remount fs read-only if block bitmap is invalid */ 583 return ext4_validate_block_bitmap(sb, desc, block_group, bh); 584 } 585 586 struct buffer_head * 587 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 588 { 589 struct buffer_head *bh; 590 int err; 591 592 bh = ext4_read_block_bitmap_nowait(sb, block_group, false); 593 if (IS_ERR(bh)) 594 return bh; 595 err = ext4_wait_block_bitmap(sb, block_group, bh); 596 if (err) { 597 put_bh(bh); 598 return ERR_PTR(err); 599 } 600 return bh; 601 } 602 603 /** 604 * ext4_has_free_clusters() 605 * @sbi: in-core super block structure. 606 * @nclusters: number of needed blocks 607 * @flags: flags from ext4_mb_new_blocks() 608 * 609 * Check if filesystem has nclusters free & available for allocation. 610 * On success return 1, return 0 on failure. 611 */ 612 static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 613 s64 nclusters, unsigned int flags) 614 { 615 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 616 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 617 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 618 619 free_clusters = percpu_counter_read_positive(fcc); 620 dirty_clusters = percpu_counter_read_positive(dcc); 621 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 622 623 /* 624 * r_blocks_count should always be multiple of the cluster ratio so 625 * we are safe to do a plane bit shift only. 626 */ 627 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 628 resv_clusters; 629 630 if (free_clusters - (nclusters + rsv + dirty_clusters) < 631 EXT4_FREECLUSTERS_WATERMARK) { 632 free_clusters = percpu_counter_sum_positive(fcc); 633 dirty_clusters = percpu_counter_sum_positive(dcc); 634 } 635 /* Check whether we have space after accounting for current 636 * dirty clusters & root reserved clusters. 637 */ 638 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 639 return 1; 640 641 /* Hm, nope. Are (enough) root reserved clusters available? */ 642 if (uid_eq(sbi->s_resuid, current_fsuid()) || 643 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 644 capable(CAP_SYS_RESOURCE) || 645 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 646 647 if (free_clusters >= (nclusters + dirty_clusters + 648 resv_clusters)) 649 return 1; 650 } 651 /* No free blocks. Let's see if we can dip into reserved pool */ 652 if (flags & EXT4_MB_USE_RESERVED) { 653 if (free_clusters >= (nclusters + dirty_clusters)) 654 return 1; 655 } 656 657 return 0; 658 } 659 660 int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 661 s64 nclusters, unsigned int flags) 662 { 663 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 664 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 665 return 0; 666 } else 667 return -ENOSPC; 668 } 669 670 /** 671 * ext4_should_retry_alloc() - check if a block allocation should be retried 672 * @sb: superblock 673 * @retries: number of retry attempts made so far 674 * 675 * ext4_should_retry_alloc() is called when ENOSPC is returned while 676 * attempting to allocate blocks. If there's an indication that a pending 677 * journal transaction might free some space and allow another attempt to 678 * succeed, this function will wait for the current or committing transaction 679 * to complete and then return TRUE. 680 */ 681 int ext4_should_retry_alloc(struct super_block *sb, int *retries) 682 { 683 struct ext4_sb_info *sbi = EXT4_SB(sb); 684 685 if (!sbi->s_journal) 686 return 0; 687 688 if (++(*retries) > 3) { 689 percpu_counter_inc(&sbi->s_sra_exceeded_retry_limit); 690 return 0; 691 } 692 693 /* 694 * if there's no indication that blocks are about to be freed it's 695 * possible we just missed a transaction commit that did so 696 */ 697 smp_mb(); 698 if (sbi->s_mb_free_pending == 0) { 699 if (test_opt(sb, DISCARD)) { 700 atomic_inc(&sbi->s_retry_alloc_pending); 701 flush_work(&sbi->s_discard_work); 702 atomic_dec(&sbi->s_retry_alloc_pending); 703 } 704 return ext4_has_free_clusters(sbi, 1, 0); 705 } 706 707 /* 708 * it's possible we've just missed a transaction commit here, 709 * so ignore the returned status 710 */ 711 ext4_debug("%s: retrying operation after ENOSPC\n", sb->s_id); 712 (void) jbd2_journal_force_commit_nested(sbi->s_journal); 713 return 1; 714 } 715 716 /* 717 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 718 * 719 * @handle: handle to this transaction 720 * @inode: file inode 721 * @goal: given target block(filesystem wide) 722 * @count: pointer to total number of clusters needed 723 * @errp: error code 724 * 725 * Return 1st allocated block number on success, *count stores total account 726 * error stores in errp pointer 727 */ 728 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 729 ext4_fsblk_t goal, unsigned int flags, 730 unsigned long *count, int *errp) 731 { 732 struct ext4_allocation_request ar; 733 ext4_fsblk_t ret; 734 735 memset(&ar, 0, sizeof(ar)); 736 /* Fill with neighbour allocated blocks */ 737 ar.inode = inode; 738 ar.goal = goal; 739 ar.len = count ? *count : 1; 740 ar.flags = flags; 741 742 ret = ext4_mb_new_blocks(handle, &ar, errp); 743 if (count) 744 *count = ar.len; 745 /* 746 * Account for the allocated meta blocks. We will never 747 * fail EDQUOT for metdata, but we do account for it. 748 */ 749 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 750 dquot_alloc_block_nofail(inode, 751 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 752 } 753 return ret; 754 } 755 756 /** 757 * ext4_count_free_clusters() -- count filesystem free clusters 758 * @sb: superblock 759 * 760 * Adds up the number of free clusters from each block group. 761 */ 762 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 763 { 764 ext4_fsblk_t desc_count; 765 struct ext4_group_desc *gdp; 766 ext4_group_t i; 767 ext4_group_t ngroups = ext4_get_groups_count(sb); 768 struct ext4_group_info *grp; 769 #ifdef EXT4FS_DEBUG 770 struct ext4_super_block *es; 771 ext4_fsblk_t bitmap_count; 772 unsigned int x; 773 struct buffer_head *bitmap_bh = NULL; 774 775 es = EXT4_SB(sb)->s_es; 776 desc_count = 0; 777 bitmap_count = 0; 778 gdp = NULL; 779 780 for (i = 0; i < ngroups; i++) { 781 gdp = ext4_get_group_desc(sb, i, NULL); 782 if (!gdp) 783 continue; 784 grp = NULL; 785 if (EXT4_SB(sb)->s_group_info) 786 grp = ext4_get_group_info(sb, i); 787 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 788 desc_count += ext4_free_group_clusters(sb, gdp); 789 brelse(bitmap_bh); 790 bitmap_bh = ext4_read_block_bitmap(sb, i); 791 if (IS_ERR(bitmap_bh)) { 792 bitmap_bh = NULL; 793 continue; 794 } 795 796 x = ext4_count_free(bitmap_bh->b_data, 797 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 798 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 799 i, ext4_free_group_clusters(sb, gdp), x); 800 bitmap_count += x; 801 } 802 brelse(bitmap_bh); 803 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 804 ", computed = %llu, %llu\n", 805 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 806 desc_count, bitmap_count); 807 return bitmap_count; 808 #else 809 desc_count = 0; 810 for (i = 0; i < ngroups; i++) { 811 gdp = ext4_get_group_desc(sb, i, NULL); 812 if (!gdp) 813 continue; 814 grp = NULL; 815 if (EXT4_SB(sb)->s_group_info) 816 grp = ext4_get_group_info(sb, i); 817 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 818 desc_count += ext4_free_group_clusters(sb, gdp); 819 } 820 821 return desc_count; 822 #endif 823 } 824 825 static inline int test_root(ext4_group_t a, int b) 826 { 827 while (1) { 828 if (a < b) 829 return 0; 830 if (a == b) 831 return 1; 832 if ((a % b) != 0) 833 return 0; 834 a = a / b; 835 } 836 } 837 838 /** 839 * ext4_bg_has_super - number of blocks used by the superblock in group 840 * @sb: superblock for filesystem 841 * @group: group number to check 842 * 843 * Return the number of blocks used by the superblock (primary or backup) 844 * in this group. Currently this will be only 0 or 1. 845 */ 846 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 847 { 848 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 849 850 if (group == 0) 851 return 1; 852 if (ext4_has_feature_sparse_super2(sb)) { 853 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 854 group == le32_to_cpu(es->s_backup_bgs[1])) 855 return 1; 856 return 0; 857 } 858 if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) 859 return 1; 860 if (!(group & 1)) 861 return 0; 862 if (test_root(group, 3) || (test_root(group, 5)) || 863 test_root(group, 7)) 864 return 1; 865 866 return 0; 867 } 868 869 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 870 ext4_group_t group) 871 { 872 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 873 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 874 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 875 876 if (group == first || group == first + 1 || group == last) 877 return 1; 878 return 0; 879 } 880 881 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 882 ext4_group_t group) 883 { 884 if (!ext4_bg_has_super(sb, group)) 885 return 0; 886 887 if (ext4_has_feature_meta_bg(sb)) 888 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 889 else 890 return EXT4_SB(sb)->s_gdb_count; 891 } 892 893 /** 894 * ext4_bg_num_gdb - number of blocks used by the group table in group 895 * @sb: superblock for filesystem 896 * @group: group number to check 897 * 898 * Return the number of blocks used by the group descriptor table 899 * (primary or backup) in this group. In the future there may be a 900 * different number of descriptor blocks in each group. 901 */ 902 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 903 { 904 unsigned long first_meta_bg = 905 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 906 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 907 908 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) 909 return ext4_bg_num_gdb_nometa(sb, group); 910 911 return ext4_bg_num_gdb_meta(sb,group); 912 913 } 914 915 /* 916 * This function returns the number of file system metadata blocks at 917 * the beginning of a block group, including the reserved gdt blocks. 918 */ 919 unsigned int ext4_num_base_meta_blocks(struct super_block *sb, 920 ext4_group_t block_group) 921 { 922 struct ext4_sb_info *sbi = EXT4_SB(sb); 923 unsigned num; 924 925 /* Check for superblock and gdt backups in this group */ 926 num = ext4_bg_has_super(sb, block_group); 927 928 if (!ext4_has_feature_meta_bg(sb) || 929 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 930 sbi->s_desc_per_block) { 931 if (num) { 932 num += ext4_bg_num_gdb_nometa(sb, block_group); 933 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 934 } 935 } else { /* For META_BG_BLOCK_GROUPS */ 936 num += ext4_bg_num_gdb_meta(sb, block_group); 937 } 938 return num; 939 } 940 941 static unsigned int ext4_num_base_meta_clusters(struct super_block *sb, 942 ext4_group_t block_group) 943 { 944 return EXT4_NUM_B2C(EXT4_SB(sb), ext4_num_base_meta_blocks(sb, block_group)); 945 } 946 947 /** 948 * ext4_inode_to_goal_block - return a hint for block allocation 949 * @inode: inode for block allocation 950 * 951 * Return the ideal location to start allocating blocks for a 952 * newly created inode. 953 */ 954 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 955 { 956 struct ext4_inode_info *ei = EXT4_I(inode); 957 ext4_group_t block_group; 958 ext4_grpblk_t colour; 959 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 960 ext4_fsblk_t bg_start; 961 ext4_fsblk_t last_block; 962 963 block_group = ei->i_block_group; 964 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 965 /* 966 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 967 * block groups per flexgroup, reserve the first block 968 * group for directories and special files. Regular 969 * files will start at the second block group. This 970 * tends to speed up directory access and improves 971 * fsck times. 972 */ 973 block_group &= ~(flex_size-1); 974 if (S_ISREG(inode->i_mode)) 975 block_group++; 976 } 977 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 978 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 979 980 /* 981 * If we are doing delayed allocation, we don't need take 982 * colour into account. 983 */ 984 if (test_opt(inode->i_sb, DELALLOC)) 985 return bg_start; 986 987 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 988 colour = (task_pid_nr(current) % 16) * 989 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 990 else 991 colour = (task_pid_nr(current) % 16) * 992 ((last_block - bg_start) / 16); 993 return bg_start + colour; 994 } 995 996