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_fsblk_t blk; 325 ext4_fsblk_t group_first_block; 326 327 if (ext4_has_feature_flex_bg(sb)) { 328 /* with FLEX_BG, the inode/block bitmaps and itable 329 * blocks may not be in the group at all 330 * so the bitmap validation will be skipped for those groups 331 * or it has to also read the block group where the bitmaps 332 * are located to verify they are set. 333 */ 334 return 0; 335 } 336 group_first_block = ext4_group_first_block_no(sb, block_group); 337 338 /* check whether block bitmap block number is set */ 339 blk = ext4_block_bitmap(sb, desc); 340 offset = blk - group_first_block; 341 if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize || 342 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 343 /* bad block bitmap */ 344 return blk; 345 346 /* check whether the inode bitmap block number is set */ 347 blk = ext4_inode_bitmap(sb, desc); 348 offset = blk - group_first_block; 349 if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize || 350 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 351 /* bad block bitmap */ 352 return blk; 353 354 /* check whether the inode table block number is set */ 355 blk = ext4_inode_table(sb, desc); 356 offset = blk - group_first_block; 357 if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize || 358 EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= sb->s_blocksize) 359 return blk; 360 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 361 EXT4_B2C(sbi, offset + sbi->s_itb_per_group), 362 EXT4_B2C(sbi, offset)); 363 if (next_zero_bit < 364 EXT4_B2C(sbi, offset + sbi->s_itb_per_group)) 365 /* bad bitmap for inode tables */ 366 return blk; 367 return 0; 368 } 369 370 static int ext4_validate_block_bitmap(struct super_block *sb, 371 struct ext4_group_desc *desc, 372 ext4_group_t block_group, 373 struct buffer_head *bh) 374 { 375 ext4_fsblk_t blk; 376 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); 377 struct ext4_sb_info *sbi = EXT4_SB(sb); 378 379 if (buffer_verified(bh)) 380 return 0; 381 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 382 return -EFSCORRUPTED; 383 384 ext4_lock_group(sb, block_group); 385 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, 386 desc, bh))) { 387 ext4_unlock_group(sb, block_group); 388 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 389 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 390 percpu_counter_sub(&sbi->s_freeclusters_counter, 391 grp->bb_free); 392 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 393 return -EFSBADCRC; 394 } 395 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 396 if (unlikely(blk != 0)) { 397 ext4_unlock_group(sb, block_group); 398 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 399 block_group, blk); 400 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 401 percpu_counter_sub(&sbi->s_freeclusters_counter, 402 grp->bb_free); 403 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 404 return -EFSCORRUPTED; 405 } 406 set_buffer_verified(bh); 407 ext4_unlock_group(sb, block_group); 408 return 0; 409 } 410 411 /** 412 * ext4_read_block_bitmap_nowait() 413 * @sb: super block 414 * @block_group: given block group 415 * 416 * Read the bitmap for a given block_group,and validate the 417 * bits for block/inode/inode tables are set in the bitmaps 418 * 419 * Return buffer_head on success or NULL in case of failure. 420 */ 421 struct buffer_head * 422 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) 423 { 424 struct ext4_group_desc *desc; 425 struct ext4_sb_info *sbi = EXT4_SB(sb); 426 struct buffer_head *bh; 427 ext4_fsblk_t bitmap_blk; 428 int err; 429 430 desc = ext4_get_group_desc(sb, block_group, NULL); 431 if (!desc) 432 return ERR_PTR(-EFSCORRUPTED); 433 bitmap_blk = ext4_block_bitmap(sb, desc); 434 if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || 435 (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { 436 ext4_error(sb, "Invalid block bitmap block %llu in " 437 "block_group %u", bitmap_blk, block_group); 438 return ERR_PTR(-EFSCORRUPTED); 439 } 440 bh = sb_getblk(sb, bitmap_blk); 441 if (unlikely(!bh)) { 442 ext4_error(sb, "Cannot get buffer for block bitmap - " 443 "block_group = %u, block_bitmap = %llu", 444 block_group, bitmap_blk); 445 return ERR_PTR(-ENOMEM); 446 } 447 448 if (bitmap_uptodate(bh)) 449 goto verify; 450 451 lock_buffer(bh); 452 if (bitmap_uptodate(bh)) { 453 unlock_buffer(bh); 454 goto verify; 455 } 456 ext4_lock_group(sb, block_group); 457 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 458 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 459 set_bitmap_uptodate(bh); 460 set_buffer_uptodate(bh); 461 set_buffer_verified(bh); 462 ext4_unlock_group(sb, block_group); 463 unlock_buffer(bh); 464 if (err) { 465 ext4_error(sb, "Failed to init block bitmap for group " 466 "%u: %d", block_group, err); 467 goto out; 468 } 469 goto verify; 470 } 471 ext4_unlock_group(sb, block_group); 472 if (buffer_uptodate(bh)) { 473 /* 474 * if not uninit if bh is uptodate, 475 * bitmap is also uptodate 476 */ 477 set_bitmap_uptodate(bh); 478 unlock_buffer(bh); 479 goto verify; 480 } 481 /* 482 * submit the buffer_head for reading 483 */ 484 set_buffer_new(bh); 485 trace_ext4_read_block_bitmap_load(sb, block_group); 486 bh->b_end_io = ext4_end_bitmap_read; 487 get_bh(bh); 488 submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh); 489 return bh; 490 verify: 491 err = ext4_validate_block_bitmap(sb, desc, block_group, bh); 492 if (err) 493 goto out; 494 return bh; 495 out: 496 put_bh(bh); 497 return ERR_PTR(err); 498 } 499 500 /* Returns 0 on success, 1 on error */ 501 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 502 struct buffer_head *bh) 503 { 504 struct ext4_group_desc *desc; 505 506 if (!buffer_new(bh)) 507 return 0; 508 desc = ext4_get_group_desc(sb, block_group, NULL); 509 if (!desc) 510 return -EFSCORRUPTED; 511 wait_on_buffer(bh); 512 if (!buffer_uptodate(bh)) { 513 ext4_error(sb, "Cannot read block bitmap - " 514 "block_group = %u, block_bitmap = %llu", 515 block_group, (unsigned long long) bh->b_blocknr); 516 return -EIO; 517 } 518 clear_buffer_new(bh); 519 /* Panic or remount fs read-only if block bitmap is invalid */ 520 return ext4_validate_block_bitmap(sb, desc, block_group, bh); 521 } 522 523 struct buffer_head * 524 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 525 { 526 struct buffer_head *bh; 527 int err; 528 529 bh = ext4_read_block_bitmap_nowait(sb, block_group); 530 if (IS_ERR(bh)) 531 return bh; 532 err = ext4_wait_block_bitmap(sb, block_group, bh); 533 if (err) { 534 put_bh(bh); 535 return ERR_PTR(err); 536 } 537 return bh; 538 } 539 540 /** 541 * ext4_has_free_clusters() 542 * @sbi: in-core super block structure. 543 * @nclusters: number of needed blocks 544 * @flags: flags from ext4_mb_new_blocks() 545 * 546 * Check if filesystem has nclusters free & available for allocation. 547 * On success return 1, return 0 on failure. 548 */ 549 static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 550 s64 nclusters, unsigned int flags) 551 { 552 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 553 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 554 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 555 556 free_clusters = percpu_counter_read_positive(fcc); 557 dirty_clusters = percpu_counter_read_positive(dcc); 558 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 559 560 /* 561 * r_blocks_count should always be multiple of the cluster ratio so 562 * we are safe to do a plane bit shift only. 563 */ 564 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 565 resv_clusters; 566 567 if (free_clusters - (nclusters + rsv + dirty_clusters) < 568 EXT4_FREECLUSTERS_WATERMARK) { 569 free_clusters = percpu_counter_sum_positive(fcc); 570 dirty_clusters = percpu_counter_sum_positive(dcc); 571 } 572 /* Check whether we have space after accounting for current 573 * dirty clusters & root reserved clusters. 574 */ 575 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 576 return 1; 577 578 /* Hm, nope. Are (enough) root reserved clusters available? */ 579 if (uid_eq(sbi->s_resuid, current_fsuid()) || 580 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 581 capable(CAP_SYS_RESOURCE) || 582 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 583 584 if (free_clusters >= (nclusters + dirty_clusters + 585 resv_clusters)) 586 return 1; 587 } 588 /* No free blocks. Let's see if we can dip into reserved pool */ 589 if (flags & EXT4_MB_USE_RESERVED) { 590 if (free_clusters >= (nclusters + dirty_clusters)) 591 return 1; 592 } 593 594 return 0; 595 } 596 597 int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 598 s64 nclusters, unsigned int flags) 599 { 600 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 601 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 602 return 0; 603 } else 604 return -ENOSPC; 605 } 606 607 /** 608 * ext4_should_retry_alloc() 609 * @sb: super block 610 * @retries number of attemps has been made 611 * 612 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if 613 * it is profitable to retry the operation, this function will wait 614 * for the current or committing transaction to complete, and then 615 * return TRUE. We will only retry once. 616 */ 617 int ext4_should_retry_alloc(struct super_block *sb, int *retries) 618 { 619 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || 620 (*retries)++ > 1 || 621 !EXT4_SB(sb)->s_journal) 622 return 0; 623 624 smp_mb(); 625 if (EXT4_SB(sb)->s_mb_free_pending == 0) 626 return 0; 627 628 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); 629 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); 630 return 1; 631 } 632 633 /* 634 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 635 * 636 * @handle: handle to this transaction 637 * @inode: file inode 638 * @goal: given target block(filesystem wide) 639 * @count: pointer to total number of clusters needed 640 * @errp: error code 641 * 642 * Return 1st allocated block number on success, *count stores total account 643 * error stores in errp pointer 644 */ 645 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 646 ext4_fsblk_t goal, unsigned int flags, 647 unsigned long *count, int *errp) 648 { 649 struct ext4_allocation_request ar; 650 ext4_fsblk_t ret; 651 652 memset(&ar, 0, sizeof(ar)); 653 /* Fill with neighbour allocated blocks */ 654 ar.inode = inode; 655 ar.goal = goal; 656 ar.len = count ? *count : 1; 657 ar.flags = flags; 658 659 ret = ext4_mb_new_blocks(handle, &ar, errp); 660 if (count) 661 *count = ar.len; 662 /* 663 * Account for the allocated meta blocks. We will never 664 * fail EDQUOT for metdata, but we do account for it. 665 */ 666 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 667 dquot_alloc_block_nofail(inode, 668 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 669 } 670 return ret; 671 } 672 673 /** 674 * ext4_count_free_clusters() -- count filesystem free clusters 675 * @sb: superblock 676 * 677 * Adds up the number of free clusters from each block group. 678 */ 679 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 680 { 681 ext4_fsblk_t desc_count; 682 struct ext4_group_desc *gdp; 683 ext4_group_t i; 684 ext4_group_t ngroups = ext4_get_groups_count(sb); 685 struct ext4_group_info *grp; 686 #ifdef EXT4FS_DEBUG 687 struct ext4_super_block *es; 688 ext4_fsblk_t bitmap_count; 689 unsigned int x; 690 struct buffer_head *bitmap_bh = NULL; 691 692 es = EXT4_SB(sb)->s_es; 693 desc_count = 0; 694 bitmap_count = 0; 695 gdp = NULL; 696 697 for (i = 0; i < ngroups; i++) { 698 gdp = ext4_get_group_desc(sb, i, NULL); 699 if (!gdp) 700 continue; 701 grp = NULL; 702 if (EXT4_SB(sb)->s_group_info) 703 grp = ext4_get_group_info(sb, i); 704 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 705 desc_count += ext4_free_group_clusters(sb, gdp); 706 brelse(bitmap_bh); 707 bitmap_bh = ext4_read_block_bitmap(sb, i); 708 if (IS_ERR(bitmap_bh)) { 709 bitmap_bh = NULL; 710 continue; 711 } 712 713 x = ext4_count_free(bitmap_bh->b_data, 714 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 715 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 716 i, ext4_free_group_clusters(sb, gdp), x); 717 bitmap_count += x; 718 } 719 brelse(bitmap_bh); 720 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 721 ", computed = %llu, %llu\n", 722 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 723 desc_count, bitmap_count); 724 return bitmap_count; 725 #else 726 desc_count = 0; 727 for (i = 0; i < ngroups; i++) { 728 gdp = ext4_get_group_desc(sb, i, NULL); 729 if (!gdp) 730 continue; 731 grp = NULL; 732 if (EXT4_SB(sb)->s_group_info) 733 grp = ext4_get_group_info(sb, i); 734 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 735 desc_count += ext4_free_group_clusters(sb, gdp); 736 } 737 738 return desc_count; 739 #endif 740 } 741 742 static inline int test_root(ext4_group_t a, int b) 743 { 744 while (1) { 745 if (a < b) 746 return 0; 747 if (a == b) 748 return 1; 749 if ((a % b) != 0) 750 return 0; 751 a = a / b; 752 } 753 } 754 755 /** 756 * ext4_bg_has_super - number of blocks used by the superblock in group 757 * @sb: superblock for filesystem 758 * @group: group number to check 759 * 760 * Return the number of blocks used by the superblock (primary or backup) 761 * in this group. Currently this will be only 0 or 1. 762 */ 763 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 764 { 765 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 766 767 if (group == 0) 768 return 1; 769 if (ext4_has_feature_sparse_super2(sb)) { 770 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 771 group == le32_to_cpu(es->s_backup_bgs[1])) 772 return 1; 773 return 0; 774 } 775 if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) 776 return 1; 777 if (!(group & 1)) 778 return 0; 779 if (test_root(group, 3) || (test_root(group, 5)) || 780 test_root(group, 7)) 781 return 1; 782 783 return 0; 784 } 785 786 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 787 ext4_group_t group) 788 { 789 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 790 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 791 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 792 793 if (group == first || group == first + 1 || group == last) 794 return 1; 795 return 0; 796 } 797 798 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 799 ext4_group_t group) 800 { 801 if (!ext4_bg_has_super(sb, group)) 802 return 0; 803 804 if (ext4_has_feature_meta_bg(sb)) 805 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 806 else 807 return EXT4_SB(sb)->s_gdb_count; 808 } 809 810 /** 811 * ext4_bg_num_gdb - number of blocks used by the group table in group 812 * @sb: superblock for filesystem 813 * @group: group number to check 814 * 815 * Return the number of blocks used by the group descriptor table 816 * (primary or backup) in this group. In the future there may be a 817 * different number of descriptor blocks in each group. 818 */ 819 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 820 { 821 unsigned long first_meta_bg = 822 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 823 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 824 825 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) 826 return ext4_bg_num_gdb_nometa(sb, group); 827 828 return ext4_bg_num_gdb_meta(sb,group); 829 830 } 831 832 /* 833 * This function returns the number of file system metadata clusters at 834 * the beginning of a block group, including the reserved gdt blocks. 835 */ 836 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 837 ext4_group_t block_group) 838 { 839 struct ext4_sb_info *sbi = EXT4_SB(sb); 840 unsigned num; 841 842 /* Check for superblock and gdt backups in this group */ 843 num = ext4_bg_has_super(sb, block_group); 844 845 if (!ext4_has_feature_meta_bg(sb) || 846 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 847 sbi->s_desc_per_block) { 848 if (num) { 849 num += ext4_bg_num_gdb(sb, block_group); 850 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 851 } 852 } else { /* For META_BG_BLOCK_GROUPS */ 853 num += ext4_bg_num_gdb(sb, block_group); 854 } 855 return EXT4_NUM_B2C(sbi, num); 856 } 857 /** 858 * ext4_inode_to_goal_block - return a hint for block allocation 859 * @inode: inode for block allocation 860 * 861 * Return the ideal location to start allocating blocks for a 862 * newly created inode. 863 */ 864 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 865 { 866 struct ext4_inode_info *ei = EXT4_I(inode); 867 ext4_group_t block_group; 868 ext4_grpblk_t colour; 869 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 870 ext4_fsblk_t bg_start; 871 ext4_fsblk_t last_block; 872 873 block_group = ei->i_block_group; 874 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 875 /* 876 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 877 * block groups per flexgroup, reserve the first block 878 * group for directories and special files. Regular 879 * files will start at the second block group. This 880 * tends to speed up directory access and improves 881 * fsck times. 882 */ 883 block_group &= ~(flex_size-1); 884 if (S_ISREG(inode->i_mode)) 885 block_group++; 886 } 887 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 888 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 889 890 /* 891 * If we are doing delayed allocation, we don't need take 892 * colour into account. 893 */ 894 if (test_opt(inode->i_sb, DELALLOC)) 895 return bg_start; 896 897 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 898 colour = (current->pid % 16) * 899 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 900 else 901 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 902 return bg_start + colour; 903 } 904 905