1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/ext4/balloc.c 4 * 5 * Copyright (C) 1992, 1993, 1994, 1995 6 * Remy Card (card@masi.ibp.fr) 7 * Laboratoire MASI - Institut Blaise Pascal 8 * Universite Pierre et Marie Curie (Paris VI) 9 * 10 * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993 11 * Big-endian to little-endian byte-swapping/bitmaps by 12 * David S. Miller (davem@caip.rutgers.edu), 1995 13 */ 14 15 #include <linux/time.h> 16 #include <linux/capability.h> 17 #include <linux/fs.h> 18 #include <linux/quotaops.h> 19 #include <linux/buffer_head.h> 20 #include "ext4.h" 21 #include "ext4_jbd2.h" 22 #include "mballoc.h" 23 24 #include <trace/events/ext4.h> 25 26 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 27 ext4_group_t block_group); 28 /* 29 * balloc.c contains the blocks allocation and deallocation routines 30 */ 31 32 /* 33 * Calculate block group number for a given block number 34 */ 35 ext4_group_t ext4_get_group_number(struct super_block *sb, 36 ext4_fsblk_t block) 37 { 38 ext4_group_t group; 39 40 if (test_opt2(sb, STD_GROUP_SIZE)) 41 group = (block - 42 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >> 43 (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3); 44 else 45 ext4_get_group_no_and_offset(sb, block, &group, NULL); 46 return group; 47 } 48 49 /* 50 * Calculate the block group number and offset into the block/cluster 51 * allocation bitmap, given a block number 52 */ 53 void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, 54 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) 55 { 56 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 57 ext4_grpblk_t offset; 58 59 blocknr = blocknr - le32_to_cpu(es->s_first_data_block); 60 offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> 61 EXT4_SB(sb)->s_cluster_bits; 62 if (offsetp) 63 *offsetp = offset; 64 if (blockgrpp) 65 *blockgrpp = blocknr; 66 67 } 68 69 /* 70 * Check whether the 'block' lives within the 'block_group'. Returns 1 if so 71 * and 0 otherwise. 72 */ 73 static inline int ext4_block_in_group(struct super_block *sb, 74 ext4_fsblk_t block, 75 ext4_group_t block_group) 76 { 77 ext4_group_t actual_group; 78 79 actual_group = ext4_get_group_number(sb, block); 80 return (actual_group == block_group) ? 1 : 0; 81 } 82 83 /* Return the number of clusters used for file system metadata; this 84 * represents the overhead needed by the file system. 85 */ 86 static unsigned ext4_num_overhead_clusters(struct super_block *sb, 87 ext4_group_t block_group, 88 struct ext4_group_desc *gdp) 89 { 90 unsigned num_clusters; 91 int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c; 92 ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); 93 ext4_fsblk_t itbl_blk; 94 struct ext4_sb_info *sbi = EXT4_SB(sb); 95 96 /* This is the number of clusters used by the superblock, 97 * block group descriptors, and reserved block group 98 * descriptor blocks */ 99 num_clusters = ext4_num_base_meta_clusters(sb, block_group); 100 101 /* 102 * For the allocation bitmaps and inode table, we first need 103 * to check to see if the block is in the block group. If it 104 * is, then check to see if the cluster is already accounted 105 * for in the clusters used for the base metadata cluster, or 106 * if we can increment the base metadata cluster to include 107 * that block. Otherwise, we will have to track the cluster 108 * used for the allocation bitmap or inode table explicitly. 109 * Normally all of these blocks are contiguous, so the special 110 * case handling shouldn't be necessary except for *very* 111 * unusual file system layouts. 112 */ 113 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { 114 block_cluster = EXT4_B2C(sbi, 115 ext4_block_bitmap(sb, gdp) - start); 116 if (block_cluster < num_clusters) 117 block_cluster = -1; 118 else if (block_cluster == num_clusters) { 119 num_clusters++; 120 block_cluster = -1; 121 } 122 } 123 124 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { 125 inode_cluster = EXT4_B2C(sbi, 126 ext4_inode_bitmap(sb, gdp) - start); 127 if (inode_cluster < num_clusters) 128 inode_cluster = -1; 129 else if (inode_cluster == num_clusters) { 130 num_clusters++; 131 inode_cluster = -1; 132 } 133 } 134 135 itbl_blk = ext4_inode_table(sb, gdp); 136 for (i = 0; i < sbi->s_itb_per_group; i++) { 137 if (ext4_block_in_group(sb, itbl_blk + i, block_group)) { 138 c = EXT4_B2C(sbi, itbl_blk + i - start); 139 if ((c < num_clusters) || (c == inode_cluster) || 140 (c == block_cluster) || (c == itbl_cluster)) 141 continue; 142 if (c == num_clusters) { 143 num_clusters++; 144 continue; 145 } 146 num_clusters++; 147 itbl_cluster = c; 148 } 149 } 150 151 if (block_cluster != -1) 152 num_clusters++; 153 if (inode_cluster != -1) 154 num_clusters++; 155 156 return num_clusters; 157 } 158 159 static unsigned int num_clusters_in_group(struct super_block *sb, 160 ext4_group_t block_group) 161 { 162 unsigned int blocks; 163 164 if (block_group == ext4_get_groups_count(sb) - 1) { 165 /* 166 * Even though mke2fs always initializes the first and 167 * last group, just in case some other tool was used, 168 * we need to make sure we calculate the right free 169 * blocks. 170 */ 171 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - 172 ext4_group_first_block_no(sb, block_group); 173 } else 174 blocks = EXT4_BLOCKS_PER_GROUP(sb); 175 return EXT4_NUM_B2C(EXT4_SB(sb), blocks); 176 } 177 178 /* Initializes an uninitialized block bitmap */ 179 static int ext4_init_block_bitmap(struct super_block *sb, 180 struct buffer_head *bh, 181 ext4_group_t block_group, 182 struct ext4_group_desc *gdp) 183 { 184 unsigned int bit, bit_max; 185 struct ext4_sb_info *sbi = EXT4_SB(sb); 186 ext4_fsblk_t start, tmp; 187 int flex_bg = 0; 188 struct ext4_group_info *grp; 189 190 J_ASSERT_BH(bh, buffer_locked(bh)); 191 192 /* If checksum is bad mark all blocks used to prevent allocation 193 * essentially implementing a per-group read-only flag. */ 194 if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) { 195 grp = ext4_get_group_info(sb, block_group); 196 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 197 percpu_counter_sub(&sbi->s_freeclusters_counter, 198 grp->bb_free); 199 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 200 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) { 201 int count; 202 count = ext4_free_inodes_count(sb, gdp); 203 percpu_counter_sub(&sbi->s_freeinodes_counter, 204 count); 205 } 206 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state); 207 return -EFSBADCRC; 208 } 209 memset(bh->b_data, 0, sb->s_blocksize); 210 211 bit_max = ext4_num_base_meta_clusters(sb, block_group); 212 if ((bit_max >> 3) >= bh->b_size) 213 return -EFSCORRUPTED; 214 215 for (bit = 0; bit < bit_max; bit++) 216 ext4_set_bit(bit, bh->b_data); 217 218 start = ext4_group_first_block_no(sb, block_group); 219 220 if (ext4_has_feature_flex_bg(sb)) 221 flex_bg = 1; 222 223 /* Set bits for block and inode bitmaps, and inode table */ 224 tmp = ext4_block_bitmap(sb, gdp); 225 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 226 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 227 228 tmp = ext4_inode_bitmap(sb, gdp); 229 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 230 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 231 232 tmp = ext4_inode_table(sb, gdp); 233 for (; tmp < ext4_inode_table(sb, gdp) + 234 sbi->s_itb_per_group; tmp++) { 235 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 236 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 237 } 238 239 /* 240 * Also if the number of blocks within the group is less than 241 * the blocksize * 8 ( which is the size of bitmap ), set rest 242 * of the block bitmap to 1 243 */ 244 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), 245 sb->s_blocksize * 8, bh->b_data); 246 return 0; 247 } 248 249 /* Return the number of free blocks in a block group. It is used when 250 * the block bitmap is uninitialized, so we can't just count the bits 251 * in the bitmap. */ 252 unsigned ext4_free_clusters_after_init(struct super_block *sb, 253 ext4_group_t block_group, 254 struct ext4_group_desc *gdp) 255 { 256 return num_clusters_in_group(sb, block_group) - 257 ext4_num_overhead_clusters(sb, block_group, gdp); 258 } 259 260 /* 261 * The free blocks are managed by bitmaps. A file system contains several 262 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 263 * block for inodes, N blocks for the inode table and data blocks. 264 * 265 * The file system contains group descriptors which are located after the 266 * super block. Each descriptor contains the number of the bitmap block and 267 * the free blocks count in the block. The descriptors are loaded in memory 268 * when a file system is mounted (see ext4_fill_super). 269 */ 270 271 /** 272 * ext4_get_group_desc() -- load group descriptor from disk 273 * @sb: super block 274 * @block_group: given block group 275 * @bh: pointer to the buffer head to store the block 276 * group descriptor 277 */ 278 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, 279 ext4_group_t block_group, 280 struct buffer_head **bh) 281 { 282 unsigned int group_desc; 283 unsigned int offset; 284 ext4_group_t ngroups = ext4_get_groups_count(sb); 285 struct ext4_group_desc *desc; 286 struct ext4_sb_info *sbi = EXT4_SB(sb); 287 288 if (block_group >= ngroups) { 289 ext4_error(sb, "block_group >= groups_count - block_group = %u," 290 " groups_count = %u", block_group, ngroups); 291 292 return NULL; 293 } 294 295 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 296 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 297 if (!sbi->s_group_desc[group_desc]) { 298 ext4_error(sb, "Group descriptor not loaded - " 299 "block_group = %u, group_desc = %u, desc = %u", 300 block_group, group_desc, offset); 301 return NULL; 302 } 303 304 desc = (struct ext4_group_desc *)( 305 (__u8 *)sbi->s_group_desc[group_desc]->b_data + 306 offset * EXT4_DESC_SIZE(sb)); 307 if (bh) 308 *bh = sbi->s_group_desc[group_desc]; 309 return desc; 310 } 311 312 /* 313 * Return the block number which was discovered to be invalid, or 0 if 314 * the block bitmap is valid. 315 */ 316 static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, 317 struct ext4_group_desc *desc, 318 ext4_group_t block_group, 319 struct buffer_head *bh) 320 { 321 struct ext4_sb_info *sbi = EXT4_SB(sb); 322 ext4_grpblk_t offset; 323 ext4_grpblk_t next_zero_bit; 324 ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); 325 ext4_fsblk_t blk; 326 ext4_fsblk_t group_first_block; 327 328 if (ext4_has_feature_flex_bg(sb)) { 329 /* with FLEX_BG, the inode/block bitmaps and itable 330 * blocks may not be in the group at all 331 * so the bitmap validation will be skipped for those groups 332 * or it has to also read the block group where the bitmaps 333 * are located to verify they are set. 334 */ 335 return 0; 336 } 337 group_first_block = ext4_group_first_block_no(sb, block_group); 338 339 /* check whether block bitmap block number is set */ 340 blk = ext4_block_bitmap(sb, desc); 341 offset = blk - group_first_block; 342 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 343 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 344 /* bad block bitmap */ 345 return blk; 346 347 /* check whether the inode bitmap block number is set */ 348 blk = ext4_inode_bitmap(sb, desc); 349 offset = blk - group_first_block; 350 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 351 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 352 /* bad block bitmap */ 353 return blk; 354 355 /* check whether the inode table block number is set */ 356 blk = ext4_inode_table(sb, desc); 357 offset = blk - group_first_block; 358 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || 359 EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit) 360 return blk; 361 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 362 EXT4_B2C(sbi, offset + sbi->s_itb_per_group), 363 EXT4_B2C(sbi, offset)); 364 if (next_zero_bit < 365 EXT4_B2C(sbi, offset + sbi->s_itb_per_group)) 366 /* bad bitmap for inode tables */ 367 return blk; 368 return 0; 369 } 370 371 static int ext4_validate_block_bitmap(struct super_block *sb, 372 struct ext4_group_desc *desc, 373 ext4_group_t block_group, 374 struct buffer_head *bh) 375 { 376 ext4_fsblk_t blk; 377 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); 378 struct ext4_sb_info *sbi = EXT4_SB(sb); 379 380 if (buffer_verified(bh)) 381 return 0; 382 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 383 return -EFSCORRUPTED; 384 385 ext4_lock_group(sb, block_group); 386 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, 387 desc, bh))) { 388 ext4_unlock_group(sb, block_group); 389 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 390 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 391 percpu_counter_sub(&sbi->s_freeclusters_counter, 392 grp->bb_free); 393 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 394 return -EFSBADCRC; 395 } 396 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 397 if (unlikely(blk != 0)) { 398 ext4_unlock_group(sb, block_group); 399 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 400 block_group, blk); 401 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 402 percpu_counter_sub(&sbi->s_freeclusters_counter, 403 grp->bb_free); 404 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 405 return -EFSCORRUPTED; 406 } 407 set_buffer_verified(bh); 408 ext4_unlock_group(sb, block_group); 409 return 0; 410 } 411 412 /** 413 * ext4_read_block_bitmap_nowait() 414 * @sb: super block 415 * @block_group: given block group 416 * 417 * Read the bitmap for a given block_group,and validate the 418 * bits for block/inode/inode tables are set in the bitmaps 419 * 420 * Return buffer_head on success or NULL in case of failure. 421 */ 422 struct buffer_head * 423 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) 424 { 425 struct ext4_group_desc *desc; 426 struct ext4_sb_info *sbi = EXT4_SB(sb); 427 struct buffer_head *bh; 428 ext4_fsblk_t bitmap_blk; 429 int err; 430 431 desc = ext4_get_group_desc(sb, block_group, NULL); 432 if (!desc) 433 return ERR_PTR(-EFSCORRUPTED); 434 bitmap_blk = ext4_block_bitmap(sb, desc); 435 if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || 436 (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { 437 ext4_error(sb, "Invalid block bitmap block %llu in " 438 "block_group %u", bitmap_blk, block_group); 439 return ERR_PTR(-EFSCORRUPTED); 440 } 441 bh = sb_getblk(sb, bitmap_blk); 442 if (unlikely(!bh)) { 443 ext4_error(sb, "Cannot get buffer for block bitmap - " 444 "block_group = %u, block_bitmap = %llu", 445 block_group, bitmap_blk); 446 return ERR_PTR(-ENOMEM); 447 } 448 449 if (bitmap_uptodate(bh)) 450 goto verify; 451 452 lock_buffer(bh); 453 if (bitmap_uptodate(bh)) { 454 unlock_buffer(bh); 455 goto verify; 456 } 457 ext4_lock_group(sb, block_group); 458 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 459 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 460 set_bitmap_uptodate(bh); 461 set_buffer_uptodate(bh); 462 set_buffer_verified(bh); 463 ext4_unlock_group(sb, block_group); 464 unlock_buffer(bh); 465 if (err) { 466 ext4_error(sb, "Failed to init block bitmap for group " 467 "%u: %d", block_group, err); 468 goto out; 469 } 470 goto verify; 471 } 472 ext4_unlock_group(sb, block_group); 473 if (buffer_uptodate(bh)) { 474 /* 475 * if not uninit if bh is uptodate, 476 * bitmap is also uptodate 477 */ 478 set_bitmap_uptodate(bh); 479 unlock_buffer(bh); 480 goto verify; 481 } 482 /* 483 * submit the buffer_head for reading 484 */ 485 set_buffer_new(bh); 486 trace_ext4_read_block_bitmap_load(sb, block_group); 487 bh->b_end_io = ext4_end_bitmap_read; 488 get_bh(bh); 489 submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh); 490 return bh; 491 verify: 492 err = ext4_validate_block_bitmap(sb, desc, block_group, bh); 493 if (err) 494 goto out; 495 return bh; 496 out: 497 put_bh(bh); 498 return ERR_PTR(err); 499 } 500 501 /* Returns 0 on success, 1 on error */ 502 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 503 struct buffer_head *bh) 504 { 505 struct ext4_group_desc *desc; 506 507 if (!buffer_new(bh)) 508 return 0; 509 desc = ext4_get_group_desc(sb, block_group, NULL); 510 if (!desc) 511 return -EFSCORRUPTED; 512 wait_on_buffer(bh); 513 if (!buffer_uptodate(bh)) { 514 ext4_error(sb, "Cannot read block bitmap - " 515 "block_group = %u, block_bitmap = %llu", 516 block_group, (unsigned long long) bh->b_blocknr); 517 return -EIO; 518 } 519 clear_buffer_new(bh); 520 /* Panic or remount fs read-only if block bitmap is invalid */ 521 return ext4_validate_block_bitmap(sb, desc, block_group, bh); 522 } 523 524 struct buffer_head * 525 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 526 { 527 struct buffer_head *bh; 528 int err; 529 530 bh = ext4_read_block_bitmap_nowait(sb, block_group); 531 if (IS_ERR(bh)) 532 return bh; 533 err = ext4_wait_block_bitmap(sb, block_group, bh); 534 if (err) { 535 put_bh(bh); 536 return ERR_PTR(err); 537 } 538 return bh; 539 } 540 541 /** 542 * ext4_has_free_clusters() 543 * @sbi: in-core super block structure. 544 * @nclusters: number of needed blocks 545 * @flags: flags from ext4_mb_new_blocks() 546 * 547 * Check if filesystem has nclusters free & available for allocation. 548 * On success return 1, return 0 on failure. 549 */ 550 static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 551 s64 nclusters, unsigned int flags) 552 { 553 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 554 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 555 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 556 557 free_clusters = percpu_counter_read_positive(fcc); 558 dirty_clusters = percpu_counter_read_positive(dcc); 559 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 560 561 /* 562 * r_blocks_count should always be multiple of the cluster ratio so 563 * we are safe to do a plane bit shift only. 564 */ 565 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 566 resv_clusters; 567 568 if (free_clusters - (nclusters + rsv + dirty_clusters) < 569 EXT4_FREECLUSTERS_WATERMARK) { 570 free_clusters = percpu_counter_sum_positive(fcc); 571 dirty_clusters = percpu_counter_sum_positive(dcc); 572 } 573 /* Check whether we have space after accounting for current 574 * dirty clusters & root reserved clusters. 575 */ 576 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 577 return 1; 578 579 /* Hm, nope. Are (enough) root reserved clusters available? */ 580 if (uid_eq(sbi->s_resuid, current_fsuid()) || 581 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 582 capable(CAP_SYS_RESOURCE) || 583 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 584 585 if (free_clusters >= (nclusters + dirty_clusters + 586 resv_clusters)) 587 return 1; 588 } 589 /* No free blocks. Let's see if we can dip into reserved pool */ 590 if (flags & EXT4_MB_USE_RESERVED) { 591 if (free_clusters >= (nclusters + dirty_clusters)) 592 return 1; 593 } 594 595 return 0; 596 } 597 598 int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 599 s64 nclusters, unsigned int flags) 600 { 601 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 602 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 603 return 0; 604 } else 605 return -ENOSPC; 606 } 607 608 /** 609 * ext4_should_retry_alloc() 610 * @sb: super block 611 * @retries number of attemps has been made 612 * 613 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if 614 * it is profitable to retry the operation, this function will wait 615 * for the current or committing transaction to complete, and then 616 * return TRUE. We will only retry once. 617 */ 618 int ext4_should_retry_alloc(struct super_block *sb, int *retries) 619 { 620 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || 621 (*retries)++ > 1 || 622 !EXT4_SB(sb)->s_journal) 623 return 0; 624 625 smp_mb(); 626 if (EXT4_SB(sb)->s_mb_free_pending == 0) 627 return 0; 628 629 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); 630 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); 631 return 1; 632 } 633 634 /* 635 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 636 * 637 * @handle: handle to this transaction 638 * @inode: file inode 639 * @goal: given target block(filesystem wide) 640 * @count: pointer to total number of clusters needed 641 * @errp: error code 642 * 643 * Return 1st allocated block number on success, *count stores total account 644 * error stores in errp pointer 645 */ 646 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 647 ext4_fsblk_t goal, unsigned int flags, 648 unsigned long *count, int *errp) 649 { 650 struct ext4_allocation_request ar; 651 ext4_fsblk_t ret; 652 653 memset(&ar, 0, sizeof(ar)); 654 /* Fill with neighbour allocated blocks */ 655 ar.inode = inode; 656 ar.goal = goal; 657 ar.len = count ? *count : 1; 658 ar.flags = flags; 659 660 ret = ext4_mb_new_blocks(handle, &ar, errp); 661 if (count) 662 *count = ar.len; 663 /* 664 * Account for the allocated meta blocks. We will never 665 * fail EDQUOT for metdata, but we do account for it. 666 */ 667 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 668 dquot_alloc_block_nofail(inode, 669 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 670 } 671 return ret; 672 } 673 674 /** 675 * ext4_count_free_clusters() -- count filesystem free clusters 676 * @sb: superblock 677 * 678 * Adds up the number of free clusters from each block group. 679 */ 680 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 681 { 682 ext4_fsblk_t desc_count; 683 struct ext4_group_desc *gdp; 684 ext4_group_t i; 685 ext4_group_t ngroups = ext4_get_groups_count(sb); 686 struct ext4_group_info *grp; 687 #ifdef EXT4FS_DEBUG 688 struct ext4_super_block *es; 689 ext4_fsblk_t bitmap_count; 690 unsigned int x; 691 struct buffer_head *bitmap_bh = NULL; 692 693 es = EXT4_SB(sb)->s_es; 694 desc_count = 0; 695 bitmap_count = 0; 696 gdp = NULL; 697 698 for (i = 0; i < ngroups; i++) { 699 gdp = ext4_get_group_desc(sb, i, NULL); 700 if (!gdp) 701 continue; 702 grp = NULL; 703 if (EXT4_SB(sb)->s_group_info) 704 grp = ext4_get_group_info(sb, i); 705 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 706 desc_count += ext4_free_group_clusters(sb, gdp); 707 brelse(bitmap_bh); 708 bitmap_bh = ext4_read_block_bitmap(sb, i); 709 if (IS_ERR(bitmap_bh)) { 710 bitmap_bh = NULL; 711 continue; 712 } 713 714 x = ext4_count_free(bitmap_bh->b_data, 715 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 716 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 717 i, ext4_free_group_clusters(sb, gdp), x); 718 bitmap_count += x; 719 } 720 brelse(bitmap_bh); 721 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 722 ", computed = %llu, %llu\n", 723 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 724 desc_count, bitmap_count); 725 return bitmap_count; 726 #else 727 desc_count = 0; 728 for (i = 0; i < ngroups; i++) { 729 gdp = ext4_get_group_desc(sb, i, NULL); 730 if (!gdp) 731 continue; 732 grp = NULL; 733 if (EXT4_SB(sb)->s_group_info) 734 grp = ext4_get_group_info(sb, i); 735 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 736 desc_count += ext4_free_group_clusters(sb, gdp); 737 } 738 739 return desc_count; 740 #endif 741 } 742 743 static inline int test_root(ext4_group_t a, int b) 744 { 745 while (1) { 746 if (a < b) 747 return 0; 748 if (a == b) 749 return 1; 750 if ((a % b) != 0) 751 return 0; 752 a = a / b; 753 } 754 } 755 756 /** 757 * ext4_bg_has_super - number of blocks used by the superblock in group 758 * @sb: superblock for filesystem 759 * @group: group number to check 760 * 761 * Return the number of blocks used by the superblock (primary or backup) 762 * in this group. Currently this will be only 0 or 1. 763 */ 764 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 765 { 766 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 767 768 if (group == 0) 769 return 1; 770 if (ext4_has_feature_sparse_super2(sb)) { 771 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 772 group == le32_to_cpu(es->s_backup_bgs[1])) 773 return 1; 774 return 0; 775 } 776 if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) 777 return 1; 778 if (!(group & 1)) 779 return 0; 780 if (test_root(group, 3) || (test_root(group, 5)) || 781 test_root(group, 7)) 782 return 1; 783 784 return 0; 785 } 786 787 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 788 ext4_group_t group) 789 { 790 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 791 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 792 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 793 794 if (group == first || group == first + 1 || group == last) 795 return 1; 796 return 0; 797 } 798 799 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 800 ext4_group_t group) 801 { 802 if (!ext4_bg_has_super(sb, group)) 803 return 0; 804 805 if (ext4_has_feature_meta_bg(sb)) 806 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 807 else 808 return EXT4_SB(sb)->s_gdb_count; 809 } 810 811 /** 812 * ext4_bg_num_gdb - number of blocks used by the group table in group 813 * @sb: superblock for filesystem 814 * @group: group number to check 815 * 816 * Return the number of blocks used by the group descriptor table 817 * (primary or backup) in this group. In the future there may be a 818 * different number of descriptor blocks in each group. 819 */ 820 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 821 { 822 unsigned long first_meta_bg = 823 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 824 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 825 826 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) 827 return ext4_bg_num_gdb_nometa(sb, group); 828 829 return ext4_bg_num_gdb_meta(sb,group); 830 831 } 832 833 /* 834 * This function returns the number of file system metadata clusters at 835 * the beginning of a block group, including the reserved gdt blocks. 836 */ 837 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 838 ext4_group_t block_group) 839 { 840 struct ext4_sb_info *sbi = EXT4_SB(sb); 841 unsigned num; 842 843 /* Check for superblock and gdt backups in this group */ 844 num = ext4_bg_has_super(sb, block_group); 845 846 if (!ext4_has_feature_meta_bg(sb) || 847 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 848 sbi->s_desc_per_block) { 849 if (num) { 850 num += ext4_bg_num_gdb(sb, block_group); 851 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 852 } 853 } else { /* For META_BG_BLOCK_GROUPS */ 854 num += ext4_bg_num_gdb(sb, block_group); 855 } 856 return EXT4_NUM_B2C(sbi, num); 857 } 858 /** 859 * ext4_inode_to_goal_block - return a hint for block allocation 860 * @inode: inode for block allocation 861 * 862 * Return the ideal location to start allocating blocks for a 863 * newly created inode. 864 */ 865 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 866 { 867 struct ext4_inode_info *ei = EXT4_I(inode); 868 ext4_group_t block_group; 869 ext4_grpblk_t colour; 870 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 871 ext4_fsblk_t bg_start; 872 ext4_fsblk_t last_block; 873 874 block_group = ei->i_block_group; 875 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 876 /* 877 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 878 * block groups per flexgroup, reserve the first block 879 * group for directories and special files. Regular 880 * files will start at the second block group. This 881 * tends to speed up directory access and improves 882 * fsck times. 883 */ 884 block_group &= ~(flex_size-1); 885 if (S_ISREG(inode->i_mode)) 886 block_group++; 887 } 888 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 889 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 890 891 /* 892 * If we are doing delayed allocation, we don't need take 893 * colour into account. 894 */ 895 if (test_opt(inode->i_sb, DELALLOC)) 896 return bg_start; 897 898 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 899 colour = (current->pid % 16) * 900 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 901 else 902 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 903 return bg_start + colour; 904 } 905 906