1 /* 2 * linux/fs/ext4/balloc.c 3 * 4 * Copyright (C) 1992, 1993, 1994, 1995 5 * Remy Card (card@masi.ibp.fr) 6 * Laboratoire MASI - Institut Blaise Pascal 7 * Universite Pierre et Marie Curie (Paris VI) 8 * 9 * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993 10 * Big-endian to little-endian byte-swapping/bitmaps by 11 * David S. Miller (davem@caip.rutgers.edu), 1995 12 */ 13 14 #include <linux/time.h> 15 #include <linux/capability.h> 16 #include <linux/fs.h> 17 #include <linux/quotaops.h> 18 #include <linux/buffer_head.h> 19 #include "ext4.h" 20 #include "ext4_jbd2.h" 21 #include "mballoc.h" 22 23 #include <trace/events/ext4.h> 24 25 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 26 ext4_group_t block_group); 27 /* 28 * balloc.c contains the blocks allocation and deallocation routines 29 */ 30 31 /* 32 * Calculate block group number for a given block number 33 */ 34 ext4_group_t ext4_get_group_number(struct super_block *sb, 35 ext4_fsblk_t block) 36 { 37 ext4_group_t group; 38 39 if (test_opt2(sb, STD_GROUP_SIZE)) 40 group = (block - 41 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >> 42 (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3); 43 else 44 ext4_get_group_no_and_offset(sb, block, &group, NULL); 45 return group; 46 } 47 48 /* 49 * Calculate the block group number and offset into the block/cluster 50 * allocation bitmap, given a block number 51 */ 52 void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, 53 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) 54 { 55 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 56 ext4_grpblk_t offset; 57 58 blocknr = blocknr - le32_to_cpu(es->s_first_data_block); 59 offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> 60 EXT4_SB(sb)->s_cluster_bits; 61 if (offsetp) 62 *offsetp = offset; 63 if (blockgrpp) 64 *blockgrpp = blocknr; 65 66 } 67 68 /* 69 * Check whether the 'block' lives within the 'block_group'. Returns 1 if so 70 * and 0 otherwise. 71 */ 72 static inline int ext4_block_in_group(struct super_block *sb, 73 ext4_fsblk_t block, 74 ext4_group_t block_group) 75 { 76 ext4_group_t actual_group; 77 78 actual_group = ext4_get_group_number(sb, block); 79 return (actual_group == block_group) ? 1 : 0; 80 } 81 82 /* Return the number of clusters used for file system metadata; this 83 * represents the overhead needed by the file system. 84 */ 85 static unsigned ext4_num_overhead_clusters(struct super_block *sb, 86 ext4_group_t block_group, 87 struct ext4_group_desc *gdp) 88 { 89 unsigned num_clusters; 90 int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c; 91 ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); 92 ext4_fsblk_t itbl_blk; 93 struct ext4_sb_info *sbi = EXT4_SB(sb); 94 95 /* This is the number of clusters used by the superblock, 96 * block group descriptors, and reserved block group 97 * descriptor blocks */ 98 num_clusters = ext4_num_base_meta_clusters(sb, block_group); 99 100 /* 101 * For the allocation bitmaps and inode table, we first need 102 * to check to see if the block is in the block group. If it 103 * is, then check to see if the cluster is already accounted 104 * for in the clusters used for the base metadata cluster, or 105 * if we can increment the base metadata cluster to include 106 * that block. Otherwise, we will have to track the cluster 107 * used for the allocation bitmap or inode table explicitly. 108 * Normally all of these blocks are contiguous, so the special 109 * case handling shouldn't be necessary except for *very* 110 * unusual file system layouts. 111 */ 112 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { 113 block_cluster = EXT4_B2C(sbi, 114 ext4_block_bitmap(sb, gdp) - start); 115 if (block_cluster < num_clusters) 116 block_cluster = -1; 117 else if (block_cluster == num_clusters) { 118 num_clusters++; 119 block_cluster = -1; 120 } 121 } 122 123 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { 124 inode_cluster = EXT4_B2C(sbi, 125 ext4_inode_bitmap(sb, gdp) - start); 126 if (inode_cluster < num_clusters) 127 inode_cluster = -1; 128 else if (inode_cluster == num_clusters) { 129 num_clusters++; 130 inode_cluster = -1; 131 } 132 } 133 134 itbl_blk = ext4_inode_table(sb, gdp); 135 for (i = 0; i < sbi->s_itb_per_group; i++) { 136 if (ext4_block_in_group(sb, itbl_blk + i, block_group)) { 137 c = EXT4_B2C(sbi, itbl_blk + i - start); 138 if ((c < num_clusters) || (c == inode_cluster) || 139 (c == block_cluster) || (c == itbl_cluster)) 140 continue; 141 if (c == num_clusters) { 142 num_clusters++; 143 continue; 144 } 145 num_clusters++; 146 itbl_cluster = c; 147 } 148 } 149 150 if (block_cluster != -1) 151 num_clusters++; 152 if (inode_cluster != -1) 153 num_clusters++; 154 155 return num_clusters; 156 } 157 158 static unsigned int num_clusters_in_group(struct super_block *sb, 159 ext4_group_t block_group) 160 { 161 unsigned int blocks; 162 163 if (block_group == ext4_get_groups_count(sb) - 1) { 164 /* 165 * Even though mke2fs always initializes the first and 166 * last group, just in case some other tool was used, 167 * we need to make sure we calculate the right free 168 * blocks. 169 */ 170 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - 171 ext4_group_first_block_no(sb, block_group); 172 } else 173 blocks = EXT4_BLOCKS_PER_GROUP(sb); 174 return EXT4_NUM_B2C(EXT4_SB(sb), blocks); 175 } 176 177 /* Initializes an uninitialized block bitmap */ 178 static int ext4_init_block_bitmap(struct super_block *sb, 179 struct buffer_head *bh, 180 ext4_group_t block_group, 181 struct ext4_group_desc *gdp) 182 { 183 unsigned int bit, bit_max; 184 struct ext4_sb_info *sbi = EXT4_SB(sb); 185 ext4_fsblk_t start, tmp; 186 int flex_bg = 0; 187 struct ext4_group_info *grp; 188 189 J_ASSERT_BH(bh, buffer_locked(bh)); 190 191 /* If checksum is bad mark all blocks used to prevent allocation 192 * essentially implementing a per-group read-only flag. */ 193 if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) { 194 ext4_error(sb, "Checksum bad for group %u", block_group); 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 for (bit = 0; bit < bit_max; bit++) 213 ext4_set_bit(bit, bh->b_data); 214 215 start = ext4_group_first_block_no(sb, block_group); 216 217 if (ext4_has_feature_flex_bg(sb)) 218 flex_bg = 1; 219 220 /* Set bits for block and inode bitmaps, and inode table */ 221 tmp = ext4_block_bitmap(sb, gdp); 222 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 223 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 224 225 tmp = ext4_inode_bitmap(sb, gdp); 226 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 227 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 228 229 tmp = ext4_inode_table(sb, gdp); 230 for (; tmp < ext4_inode_table(sb, gdp) + 231 sbi->s_itb_per_group; tmp++) { 232 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 233 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 234 } 235 236 /* 237 * Also if the number of blocks within the group is less than 238 * the blocksize * 8 ( which is the size of bitmap ), set rest 239 * of the block bitmap to 1 240 */ 241 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), 242 sb->s_blocksize * 8, bh->b_data); 243 ext4_block_bitmap_csum_set(sb, block_group, gdp, bh); 244 ext4_group_desc_csum_set(sb, block_group, gdp); 245 return 0; 246 } 247 248 /* Return the number of free blocks in a block group. It is used when 249 * the block bitmap is uninitialized, so we can't just count the bits 250 * in the bitmap. */ 251 unsigned ext4_free_clusters_after_init(struct super_block *sb, 252 ext4_group_t block_group, 253 struct ext4_group_desc *gdp) 254 { 255 return num_clusters_in_group(sb, block_group) - 256 ext4_num_overhead_clusters(sb, block_group, gdp); 257 } 258 259 /* 260 * The free blocks are managed by bitmaps. A file system contains several 261 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 262 * block for inodes, N blocks for the inode table and data blocks. 263 * 264 * The file system contains group descriptors which are located after the 265 * super block. Each descriptor contains the number of the bitmap block and 266 * the free blocks count in the block. The descriptors are loaded in memory 267 * when a file system is mounted (see ext4_fill_super). 268 */ 269 270 /** 271 * ext4_get_group_desc() -- load group descriptor from disk 272 * @sb: super block 273 * @block_group: given block group 274 * @bh: pointer to the buffer head to store the block 275 * group descriptor 276 */ 277 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, 278 ext4_group_t block_group, 279 struct buffer_head **bh) 280 { 281 unsigned int group_desc; 282 unsigned int offset; 283 ext4_group_t ngroups = ext4_get_groups_count(sb); 284 struct ext4_group_desc *desc; 285 struct ext4_sb_info *sbi = EXT4_SB(sb); 286 287 if (block_group >= ngroups) { 288 ext4_error(sb, "block_group >= groups_count - block_group = %u," 289 " groups_count = %u", block_group, ngroups); 290 291 return NULL; 292 } 293 294 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 295 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 296 if (!sbi->s_group_desc[group_desc]) { 297 ext4_error(sb, "Group descriptor not loaded - " 298 "block_group = %u, group_desc = %u, desc = %u", 299 block_group, group_desc, offset); 300 return NULL; 301 } 302 303 desc = (struct ext4_group_desc *)( 304 (__u8 *)sbi->s_group_desc[group_desc]->b_data + 305 offset * EXT4_DESC_SIZE(sb)); 306 if (bh) 307 *bh = sbi->s_group_desc[group_desc]; 308 return desc; 309 } 310 311 /* 312 * Return the block number which was discovered to be invalid, or 0 if 313 * the block bitmap is valid. 314 */ 315 static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, 316 struct ext4_group_desc *desc, 317 ext4_group_t block_group, 318 struct buffer_head *bh) 319 { 320 struct ext4_sb_info *sbi = EXT4_SB(sb); 321 ext4_grpblk_t offset; 322 ext4_grpblk_t next_zero_bit; 323 ext4_fsblk_t blk; 324 ext4_fsblk_t group_first_block; 325 326 if (ext4_has_feature_flex_bg(sb)) { 327 /* with FLEX_BG, the inode/block bitmaps and itable 328 * blocks may not be in the group at all 329 * so the bitmap validation will be skipped for those groups 330 * or it has to also read the block group where the bitmaps 331 * are located to verify they are set. 332 */ 333 return 0; 334 } 335 group_first_block = ext4_group_first_block_no(sb, block_group); 336 337 /* check whether block bitmap block number is set */ 338 blk = ext4_block_bitmap(sb, desc); 339 offset = blk - group_first_block; 340 if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 341 /* bad block bitmap */ 342 return blk; 343 344 /* check whether the inode bitmap block number is set */ 345 blk = ext4_inode_bitmap(sb, desc); 346 offset = blk - group_first_block; 347 if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 348 /* bad block bitmap */ 349 return blk; 350 351 /* check whether the inode table block number is set */ 352 blk = ext4_inode_table(sb, desc); 353 offset = blk - group_first_block; 354 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 355 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group), 356 EXT4_B2C(sbi, offset)); 357 if (next_zero_bit < 358 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group)) 359 /* bad bitmap for inode tables */ 360 return blk; 361 return 0; 362 } 363 364 static int ext4_validate_block_bitmap(struct super_block *sb, 365 struct ext4_group_desc *desc, 366 ext4_group_t block_group, 367 struct buffer_head *bh) 368 { 369 ext4_fsblk_t blk; 370 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); 371 struct ext4_sb_info *sbi = EXT4_SB(sb); 372 373 if (buffer_verified(bh)) 374 return 0; 375 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 376 return -EFSCORRUPTED; 377 378 ext4_lock_group(sb, block_group); 379 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, 380 desc, bh))) { 381 ext4_unlock_group(sb, block_group); 382 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 383 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 384 percpu_counter_sub(&sbi->s_freeclusters_counter, 385 grp->bb_free); 386 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 387 return -EFSBADCRC; 388 } 389 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 390 if (unlikely(blk != 0)) { 391 ext4_unlock_group(sb, block_group); 392 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 393 block_group, blk); 394 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 395 percpu_counter_sub(&sbi->s_freeclusters_counter, 396 grp->bb_free); 397 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 398 return -EFSCORRUPTED; 399 } 400 set_buffer_verified(bh); 401 ext4_unlock_group(sb, block_group); 402 return 0; 403 } 404 405 /** 406 * ext4_read_block_bitmap_nowait() 407 * @sb: super block 408 * @block_group: given block group 409 * 410 * Read the bitmap for a given block_group,and validate the 411 * bits for block/inode/inode tables are set in the bitmaps 412 * 413 * Return buffer_head on success or NULL in case of failure. 414 */ 415 struct buffer_head * 416 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) 417 { 418 struct ext4_group_desc *desc; 419 struct buffer_head *bh; 420 ext4_fsblk_t bitmap_blk; 421 int err; 422 423 desc = ext4_get_group_desc(sb, block_group, NULL); 424 if (!desc) 425 return ERR_PTR(-EFSCORRUPTED); 426 bitmap_blk = ext4_block_bitmap(sb, desc); 427 bh = sb_getblk(sb, bitmap_blk); 428 if (unlikely(!bh)) { 429 ext4_error(sb, "Cannot get buffer for block bitmap - " 430 "block_group = %u, block_bitmap = %llu", 431 block_group, bitmap_blk); 432 return ERR_PTR(-ENOMEM); 433 } 434 435 if (bitmap_uptodate(bh)) 436 goto verify; 437 438 lock_buffer(bh); 439 if (bitmap_uptodate(bh)) { 440 unlock_buffer(bh); 441 goto verify; 442 } 443 ext4_lock_group(sb, block_group); 444 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 445 446 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 447 set_bitmap_uptodate(bh); 448 set_buffer_uptodate(bh); 449 ext4_unlock_group(sb, block_group); 450 unlock_buffer(bh); 451 if (err) 452 goto out; 453 goto verify; 454 } 455 ext4_unlock_group(sb, block_group); 456 if (buffer_uptodate(bh)) { 457 /* 458 * if not uninit if bh is uptodate, 459 * bitmap is also uptodate 460 */ 461 set_bitmap_uptodate(bh); 462 unlock_buffer(bh); 463 goto verify; 464 } 465 /* 466 * submit the buffer_head for reading 467 */ 468 set_buffer_new(bh); 469 trace_ext4_read_block_bitmap_load(sb, block_group); 470 bh->b_end_io = ext4_end_bitmap_read; 471 get_bh(bh); 472 submit_bh(READ | REQ_META | REQ_PRIO, bh); 473 return bh; 474 verify: 475 err = ext4_validate_block_bitmap(sb, desc, block_group, bh); 476 if (err) 477 goto out; 478 return bh; 479 out: 480 put_bh(bh); 481 return ERR_PTR(err); 482 } 483 484 /* Returns 0 on success, 1 on error */ 485 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 486 struct buffer_head *bh) 487 { 488 struct ext4_group_desc *desc; 489 490 if (!buffer_new(bh)) 491 return 0; 492 desc = ext4_get_group_desc(sb, block_group, NULL); 493 if (!desc) 494 return -EFSCORRUPTED; 495 wait_on_buffer(bh); 496 if (!buffer_uptodate(bh)) { 497 ext4_error(sb, "Cannot read block bitmap - " 498 "block_group = %u, block_bitmap = %llu", 499 block_group, (unsigned long long) bh->b_blocknr); 500 return -EIO; 501 } 502 clear_buffer_new(bh); 503 /* Panic or remount fs read-only if block bitmap is invalid */ 504 return ext4_validate_block_bitmap(sb, desc, block_group, bh); 505 } 506 507 struct buffer_head * 508 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 509 { 510 struct buffer_head *bh; 511 int err; 512 513 bh = ext4_read_block_bitmap_nowait(sb, block_group); 514 if (IS_ERR(bh)) 515 return bh; 516 err = ext4_wait_block_bitmap(sb, block_group, bh); 517 if (err) { 518 put_bh(bh); 519 return ERR_PTR(err); 520 } 521 return bh; 522 } 523 524 /** 525 * ext4_has_free_clusters() 526 * @sbi: in-core super block structure. 527 * @nclusters: number of needed blocks 528 * @flags: flags from ext4_mb_new_blocks() 529 * 530 * Check if filesystem has nclusters free & available for allocation. 531 * On success return 1, return 0 on failure. 532 */ 533 static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 534 s64 nclusters, unsigned int flags) 535 { 536 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 537 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 538 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 539 540 free_clusters = percpu_counter_read_positive(fcc); 541 dirty_clusters = percpu_counter_read_positive(dcc); 542 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 543 544 /* 545 * r_blocks_count should always be multiple of the cluster ratio so 546 * we are safe to do a plane bit shift only. 547 */ 548 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 549 resv_clusters; 550 551 if (free_clusters - (nclusters + rsv + dirty_clusters) < 552 EXT4_FREECLUSTERS_WATERMARK) { 553 free_clusters = percpu_counter_sum_positive(fcc); 554 dirty_clusters = percpu_counter_sum_positive(dcc); 555 } 556 /* Check whether we have space after accounting for current 557 * dirty clusters & root reserved clusters. 558 */ 559 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 560 return 1; 561 562 /* Hm, nope. Are (enough) root reserved clusters available? */ 563 if (uid_eq(sbi->s_resuid, current_fsuid()) || 564 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 565 capable(CAP_SYS_RESOURCE) || 566 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 567 568 if (free_clusters >= (nclusters + dirty_clusters + 569 resv_clusters)) 570 return 1; 571 } 572 /* No free blocks. Let's see if we can dip into reserved pool */ 573 if (flags & EXT4_MB_USE_RESERVED) { 574 if (free_clusters >= (nclusters + dirty_clusters)) 575 return 1; 576 } 577 578 return 0; 579 } 580 581 int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 582 s64 nclusters, unsigned int flags) 583 { 584 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 585 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 586 return 0; 587 } else 588 return -ENOSPC; 589 } 590 591 /** 592 * ext4_should_retry_alloc() 593 * @sb: super block 594 * @retries number of attemps has been made 595 * 596 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if 597 * it is profitable to retry the operation, this function will wait 598 * for the current or committing transaction to complete, and then 599 * return TRUE. 600 * 601 * if the total number of retries exceed three times, return FALSE. 602 */ 603 int ext4_should_retry_alloc(struct super_block *sb, int *retries) 604 { 605 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || 606 (*retries)++ > 3 || 607 !EXT4_SB(sb)->s_journal) 608 return 0; 609 610 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); 611 612 return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); 613 } 614 615 /* 616 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 617 * 618 * @handle: handle to this transaction 619 * @inode: file inode 620 * @goal: given target block(filesystem wide) 621 * @count: pointer to total number of clusters needed 622 * @errp: error code 623 * 624 * Return 1st allocated block number on success, *count stores total account 625 * error stores in errp pointer 626 */ 627 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 628 ext4_fsblk_t goal, unsigned int flags, 629 unsigned long *count, int *errp) 630 { 631 struct ext4_allocation_request ar; 632 ext4_fsblk_t ret; 633 634 memset(&ar, 0, sizeof(ar)); 635 /* Fill with neighbour allocated blocks */ 636 ar.inode = inode; 637 ar.goal = goal; 638 ar.len = count ? *count : 1; 639 ar.flags = flags; 640 641 ret = ext4_mb_new_blocks(handle, &ar, errp); 642 if (count) 643 *count = ar.len; 644 /* 645 * Account for the allocated meta blocks. We will never 646 * fail EDQUOT for metdata, but we do account for it. 647 */ 648 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 649 dquot_alloc_block_nofail(inode, 650 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 651 } 652 return ret; 653 } 654 655 /** 656 * ext4_count_free_clusters() -- count filesystem free clusters 657 * @sb: superblock 658 * 659 * Adds up the number of free clusters from each block group. 660 */ 661 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 662 { 663 ext4_fsblk_t desc_count; 664 struct ext4_group_desc *gdp; 665 ext4_group_t i; 666 ext4_group_t ngroups = ext4_get_groups_count(sb); 667 struct ext4_group_info *grp; 668 #ifdef EXT4FS_DEBUG 669 struct ext4_super_block *es; 670 ext4_fsblk_t bitmap_count; 671 unsigned int x; 672 struct buffer_head *bitmap_bh = NULL; 673 674 es = EXT4_SB(sb)->s_es; 675 desc_count = 0; 676 bitmap_count = 0; 677 gdp = NULL; 678 679 for (i = 0; i < ngroups; i++) { 680 gdp = ext4_get_group_desc(sb, i, NULL); 681 if (!gdp) 682 continue; 683 grp = NULL; 684 if (EXT4_SB(sb)->s_group_info) 685 grp = ext4_get_group_info(sb, i); 686 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 687 desc_count += ext4_free_group_clusters(sb, gdp); 688 brelse(bitmap_bh); 689 bitmap_bh = ext4_read_block_bitmap(sb, i); 690 if (IS_ERR(bitmap_bh)) { 691 bitmap_bh = NULL; 692 continue; 693 } 694 695 x = ext4_count_free(bitmap_bh->b_data, 696 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 697 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 698 i, ext4_free_group_clusters(sb, gdp), x); 699 bitmap_count += x; 700 } 701 brelse(bitmap_bh); 702 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 703 ", computed = %llu, %llu\n", 704 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 705 desc_count, bitmap_count); 706 return bitmap_count; 707 #else 708 desc_count = 0; 709 for (i = 0; i < ngroups; i++) { 710 gdp = ext4_get_group_desc(sb, i, NULL); 711 if (!gdp) 712 continue; 713 grp = NULL; 714 if (EXT4_SB(sb)->s_group_info) 715 grp = ext4_get_group_info(sb, i); 716 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 717 desc_count += ext4_free_group_clusters(sb, gdp); 718 } 719 720 return desc_count; 721 #endif 722 } 723 724 static inline int test_root(ext4_group_t a, int b) 725 { 726 while (1) { 727 if (a < b) 728 return 0; 729 if (a == b) 730 return 1; 731 if ((a % b) != 0) 732 return 0; 733 a = a / b; 734 } 735 } 736 737 /** 738 * ext4_bg_has_super - number of blocks used by the superblock in group 739 * @sb: superblock for filesystem 740 * @group: group number to check 741 * 742 * Return the number of blocks used by the superblock (primary or backup) 743 * in this group. Currently this will be only 0 or 1. 744 */ 745 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 746 { 747 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 748 749 if (group == 0) 750 return 1; 751 if (ext4_has_feature_sparse_super2(sb)) { 752 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 753 group == le32_to_cpu(es->s_backup_bgs[1])) 754 return 1; 755 return 0; 756 } 757 if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) 758 return 1; 759 if (!(group & 1)) 760 return 0; 761 if (test_root(group, 3) || (test_root(group, 5)) || 762 test_root(group, 7)) 763 return 1; 764 765 return 0; 766 } 767 768 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 769 ext4_group_t group) 770 { 771 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 772 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 773 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 774 775 if (group == first || group == first + 1 || group == last) 776 return 1; 777 return 0; 778 } 779 780 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 781 ext4_group_t group) 782 { 783 if (!ext4_bg_has_super(sb, group)) 784 return 0; 785 786 if (ext4_has_feature_meta_bg(sb)) 787 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 788 else 789 return EXT4_SB(sb)->s_gdb_count; 790 } 791 792 /** 793 * ext4_bg_num_gdb - number of blocks used by the group table in group 794 * @sb: superblock for filesystem 795 * @group: group number to check 796 * 797 * Return the number of blocks used by the group descriptor table 798 * (primary or backup) in this group. In the future there may be a 799 * different number of descriptor blocks in each group. 800 */ 801 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 802 { 803 unsigned long first_meta_bg = 804 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 805 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 806 807 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) 808 return ext4_bg_num_gdb_nometa(sb, group); 809 810 return ext4_bg_num_gdb_meta(sb,group); 811 812 } 813 814 /* 815 * This function returns the number of file system metadata clusters at 816 * the beginning of a block group, including the reserved gdt blocks. 817 */ 818 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 819 ext4_group_t block_group) 820 { 821 struct ext4_sb_info *sbi = EXT4_SB(sb); 822 unsigned num; 823 824 /* Check for superblock and gdt backups in this group */ 825 num = ext4_bg_has_super(sb, block_group); 826 827 if (!ext4_has_feature_meta_bg(sb) || 828 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 829 sbi->s_desc_per_block) { 830 if (num) { 831 num += ext4_bg_num_gdb(sb, block_group); 832 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 833 } 834 } else { /* For META_BG_BLOCK_GROUPS */ 835 num += ext4_bg_num_gdb(sb, block_group); 836 } 837 return EXT4_NUM_B2C(sbi, num); 838 } 839 /** 840 * ext4_inode_to_goal_block - return a hint for block allocation 841 * @inode: inode for block allocation 842 * 843 * Return the ideal location to start allocating blocks for a 844 * newly created inode. 845 */ 846 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 847 { 848 struct ext4_inode_info *ei = EXT4_I(inode); 849 ext4_group_t block_group; 850 ext4_grpblk_t colour; 851 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 852 ext4_fsblk_t bg_start; 853 ext4_fsblk_t last_block; 854 855 block_group = ei->i_block_group; 856 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 857 /* 858 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 859 * block groups per flexgroup, reserve the first block 860 * group for directories and special files. Regular 861 * files will start at the second block group. This 862 * tends to speed up directory access and improves 863 * fsck times. 864 */ 865 block_group &= ~(flex_size-1); 866 if (S_ISREG(inode->i_mode)) 867 block_group++; 868 } 869 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 870 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 871 872 /* 873 * If we are doing delayed allocation, we don't need take 874 * colour into account. 875 */ 876 if (test_opt(inode->i_sb, DELALLOC)) 877 return bg_start; 878 879 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 880 colour = (current->pid % 16) * 881 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 882 else 883 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 884 return bg_start + colour; 885 } 886 887