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 grp = ext4_get_group_info(sb, block_group); 195 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 196 percpu_counter_sub(&sbi->s_freeclusters_counter, 197 grp->bb_free); 198 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 199 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) { 200 int count; 201 count = ext4_free_inodes_count(sb, gdp); 202 percpu_counter_sub(&sbi->s_freeinodes_counter, 203 count); 204 } 205 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state); 206 return -EIO; 207 } 208 memset(bh->b_data, 0, sb->s_blocksize); 209 210 bit_max = ext4_num_base_meta_clusters(sb, block_group); 211 for (bit = 0; bit < bit_max; bit++) 212 ext4_set_bit(bit, bh->b_data); 213 214 start = ext4_group_first_block_no(sb, block_group); 215 216 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) 217 flex_bg = 1; 218 219 /* Set bits for block and inode bitmaps, and inode table */ 220 tmp = ext4_block_bitmap(sb, gdp); 221 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 222 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 223 224 tmp = ext4_inode_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_table(sb, gdp); 229 for (; tmp < ext4_inode_table(sb, gdp) + 230 sbi->s_itb_per_group; tmp++) { 231 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 232 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 233 } 234 235 /* 236 * Also if the number of blocks within the group is less than 237 * the blocksize * 8 ( which is the size of bitmap ), set rest 238 * of the block bitmap to 1 239 */ 240 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), 241 sb->s_blocksize * 8, bh->b_data); 242 ext4_block_bitmap_csum_set(sb, block_group, gdp, bh); 243 ext4_group_desc_csum_set(sb, block_group, gdp); 244 return 0; 245 } 246 247 /* Return the number of free blocks in a block group. It is used when 248 * the block bitmap is uninitialized, so we can't just count the bits 249 * in the bitmap. */ 250 unsigned ext4_free_clusters_after_init(struct super_block *sb, 251 ext4_group_t block_group, 252 struct ext4_group_desc *gdp) 253 { 254 return num_clusters_in_group(sb, block_group) - 255 ext4_num_overhead_clusters(sb, block_group, gdp); 256 } 257 258 /* 259 * The free blocks are managed by bitmaps. A file system contains several 260 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 261 * block for inodes, N blocks for the inode table and data blocks. 262 * 263 * The file system contains group descriptors which are located after the 264 * super block. Each descriptor contains the number of the bitmap block and 265 * the free blocks count in the block. The descriptors are loaded in memory 266 * when a file system is mounted (see ext4_fill_super). 267 */ 268 269 /** 270 * ext4_get_group_desc() -- load group descriptor from disk 271 * @sb: super block 272 * @block_group: given block group 273 * @bh: pointer to the buffer head to store the block 274 * group descriptor 275 */ 276 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, 277 ext4_group_t block_group, 278 struct buffer_head **bh) 279 { 280 unsigned int group_desc; 281 unsigned int offset; 282 ext4_group_t ngroups = ext4_get_groups_count(sb); 283 struct ext4_group_desc *desc; 284 struct ext4_sb_info *sbi = EXT4_SB(sb); 285 286 if (block_group >= ngroups) { 287 ext4_error(sb, "block_group >= groups_count - block_group = %u," 288 " groups_count = %u", block_group, ngroups); 289 290 return NULL; 291 } 292 293 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 294 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 295 if (!sbi->s_group_desc[group_desc]) { 296 ext4_error(sb, "Group descriptor not loaded - " 297 "block_group = %u, group_desc = %u, desc = %u", 298 block_group, group_desc, offset); 299 return NULL; 300 } 301 302 desc = (struct ext4_group_desc *)( 303 (__u8 *)sbi->s_group_desc[group_desc]->b_data + 304 offset * EXT4_DESC_SIZE(sb)); 305 if (bh) 306 *bh = sbi->s_group_desc[group_desc]; 307 return desc; 308 } 309 310 /* 311 * Return the block number which was discovered to be invalid, or 0 if 312 * the block bitmap is valid. 313 */ 314 static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, 315 struct ext4_group_desc *desc, 316 ext4_group_t block_group, 317 struct buffer_head *bh) 318 { 319 struct ext4_sb_info *sbi = EXT4_SB(sb); 320 ext4_grpblk_t offset; 321 ext4_grpblk_t next_zero_bit; 322 ext4_fsblk_t blk; 323 ext4_fsblk_t group_first_block; 324 325 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { 326 /* with FLEX_BG, the inode/block bitmaps and itable 327 * blocks may not be in the group at all 328 * so the bitmap validation will be skipped for those groups 329 * or it has to also read the block group where the bitmaps 330 * are located to verify they are set. 331 */ 332 return 0; 333 } 334 group_first_block = ext4_group_first_block_no(sb, block_group); 335 336 /* check whether block bitmap block number is set */ 337 blk = ext4_block_bitmap(sb, desc); 338 offset = blk - group_first_block; 339 if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 340 /* bad block bitmap */ 341 return blk; 342 343 /* check whether the inode bitmap block number is set */ 344 blk = ext4_inode_bitmap(sb, desc); 345 offset = blk - group_first_block; 346 if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 347 /* bad block bitmap */ 348 return blk; 349 350 /* check whether the inode table block number is set */ 351 blk = ext4_inode_table(sb, desc); 352 offset = blk - group_first_block; 353 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 354 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group), 355 EXT4_B2C(sbi, offset)); 356 if (next_zero_bit < 357 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group)) 358 /* bad bitmap for inode tables */ 359 return blk; 360 return 0; 361 } 362 363 static void ext4_validate_block_bitmap(struct super_block *sb, 364 struct ext4_group_desc *desc, 365 ext4_group_t block_group, 366 struct buffer_head *bh) 367 { 368 ext4_fsblk_t blk; 369 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); 370 struct ext4_sb_info *sbi = EXT4_SB(sb); 371 372 if (buffer_verified(bh) || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 373 return; 374 375 ext4_lock_group(sb, block_group); 376 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 377 if (unlikely(blk != 0)) { 378 ext4_unlock_group(sb, block_group); 379 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 380 block_group, blk); 381 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 382 percpu_counter_sub(&sbi->s_freeclusters_counter, 383 grp->bb_free); 384 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 385 return; 386 } 387 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, 388 desc, bh))) { 389 ext4_unlock_group(sb, block_group); 390 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 391 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 392 percpu_counter_sub(&sbi->s_freeclusters_counter, 393 grp->bb_free); 394 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 395 return; 396 } 397 set_buffer_verified(bh); 398 ext4_unlock_group(sb, block_group); 399 } 400 401 /** 402 * ext4_read_block_bitmap_nowait() 403 * @sb: super block 404 * @block_group: given block group 405 * 406 * Read the bitmap for a given block_group,and validate the 407 * bits for block/inode/inode tables are set in the bitmaps 408 * 409 * Return buffer_head on success or NULL in case of failure. 410 */ 411 struct buffer_head * 412 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) 413 { 414 struct ext4_group_desc *desc; 415 struct buffer_head *bh; 416 ext4_fsblk_t bitmap_blk; 417 418 desc = ext4_get_group_desc(sb, block_group, NULL); 419 if (!desc) 420 return NULL; 421 bitmap_blk = ext4_block_bitmap(sb, desc); 422 bh = sb_getblk(sb, bitmap_blk); 423 if (unlikely(!bh)) { 424 ext4_error(sb, "Cannot get buffer for block bitmap - " 425 "block_group = %u, block_bitmap = %llu", 426 block_group, bitmap_blk); 427 return NULL; 428 } 429 430 if (bitmap_uptodate(bh)) 431 goto verify; 432 433 lock_buffer(bh); 434 if (bitmap_uptodate(bh)) { 435 unlock_buffer(bh); 436 goto verify; 437 } 438 ext4_lock_group(sb, block_group); 439 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 440 int err; 441 442 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 443 set_bitmap_uptodate(bh); 444 set_buffer_uptodate(bh); 445 ext4_unlock_group(sb, block_group); 446 unlock_buffer(bh); 447 if (err) 448 ext4_error(sb, "Checksum bad for grp %u", block_group); 449 goto verify; 450 } 451 ext4_unlock_group(sb, block_group); 452 if (buffer_uptodate(bh)) { 453 /* 454 * if not uninit if bh is uptodate, 455 * bitmap is also uptodate 456 */ 457 set_bitmap_uptodate(bh); 458 unlock_buffer(bh); 459 goto verify; 460 } 461 /* 462 * submit the buffer_head for reading 463 */ 464 set_buffer_new(bh); 465 trace_ext4_read_block_bitmap_load(sb, block_group); 466 bh->b_end_io = ext4_end_bitmap_read; 467 get_bh(bh); 468 submit_bh(READ | REQ_META | REQ_PRIO, bh); 469 return bh; 470 verify: 471 ext4_validate_block_bitmap(sb, desc, block_group, bh); 472 if (buffer_verified(bh)) 473 return bh; 474 put_bh(bh); 475 return NULL; 476 } 477 478 /* Returns 0 on success, 1 on error */ 479 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 480 struct buffer_head *bh) 481 { 482 struct ext4_group_desc *desc; 483 484 if (!buffer_new(bh)) 485 return 0; 486 desc = ext4_get_group_desc(sb, block_group, NULL); 487 if (!desc) 488 return 1; 489 wait_on_buffer(bh); 490 if (!buffer_uptodate(bh)) { 491 ext4_error(sb, "Cannot read block bitmap - " 492 "block_group = %u, block_bitmap = %llu", 493 block_group, (unsigned long long) bh->b_blocknr); 494 return 1; 495 } 496 clear_buffer_new(bh); 497 /* Panic or remount fs read-only if block bitmap is invalid */ 498 ext4_validate_block_bitmap(sb, desc, block_group, bh); 499 /* ...but check for error just in case errors=continue. */ 500 return !buffer_verified(bh); 501 } 502 503 struct buffer_head * 504 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 505 { 506 struct buffer_head *bh; 507 508 bh = ext4_read_block_bitmap_nowait(sb, block_group); 509 if (!bh) 510 return NULL; 511 if (ext4_wait_block_bitmap(sb, block_group, bh)) { 512 put_bh(bh); 513 return NULL; 514 } 515 return bh; 516 } 517 518 /** 519 * ext4_has_free_clusters() 520 * @sbi: in-core super block structure. 521 * @nclusters: number of needed blocks 522 * @flags: flags from ext4_mb_new_blocks() 523 * 524 * Check if filesystem has nclusters free & available for allocation. 525 * On success return 1, return 0 on failure. 526 */ 527 static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 528 s64 nclusters, unsigned int flags) 529 { 530 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 531 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 532 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 533 534 free_clusters = percpu_counter_read_positive(fcc); 535 dirty_clusters = percpu_counter_read_positive(dcc); 536 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 537 538 /* 539 * r_blocks_count should always be multiple of the cluster ratio so 540 * we are safe to do a plane bit shift only. 541 */ 542 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 543 resv_clusters; 544 545 if (free_clusters - (nclusters + rsv + dirty_clusters) < 546 EXT4_FREECLUSTERS_WATERMARK) { 547 free_clusters = percpu_counter_sum_positive(fcc); 548 dirty_clusters = percpu_counter_sum_positive(dcc); 549 } 550 /* Check whether we have space after accounting for current 551 * dirty clusters & root reserved clusters. 552 */ 553 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 554 return 1; 555 556 /* Hm, nope. Are (enough) root reserved clusters available? */ 557 if (uid_eq(sbi->s_resuid, current_fsuid()) || 558 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 559 capable(CAP_SYS_RESOURCE) || 560 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 561 562 if (free_clusters >= (nclusters + dirty_clusters + 563 resv_clusters)) 564 return 1; 565 } 566 /* No free blocks. Let's see if we can dip into reserved pool */ 567 if (flags & EXT4_MB_USE_RESERVED) { 568 if (free_clusters >= (nclusters + dirty_clusters)) 569 return 1; 570 } 571 572 return 0; 573 } 574 575 int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 576 s64 nclusters, unsigned int flags) 577 { 578 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 579 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 580 return 0; 581 } else 582 return -ENOSPC; 583 } 584 585 /** 586 * ext4_should_retry_alloc() 587 * @sb: super block 588 * @retries number of attemps has been made 589 * 590 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if 591 * it is profitable to retry the operation, this function will wait 592 * for the current or committing transaction to complete, and then 593 * return TRUE. 594 * 595 * if the total number of retries exceed three times, return FALSE. 596 */ 597 int ext4_should_retry_alloc(struct super_block *sb, int *retries) 598 { 599 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || 600 (*retries)++ > 3 || 601 !EXT4_SB(sb)->s_journal) 602 return 0; 603 604 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); 605 606 return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); 607 } 608 609 /* 610 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 611 * 612 * @handle: handle to this transaction 613 * @inode: file inode 614 * @goal: given target block(filesystem wide) 615 * @count: pointer to total number of clusters needed 616 * @errp: error code 617 * 618 * Return 1st allocated block number on success, *count stores total account 619 * error stores in errp pointer 620 */ 621 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 622 ext4_fsblk_t goal, unsigned int flags, 623 unsigned long *count, int *errp) 624 { 625 struct ext4_allocation_request ar; 626 ext4_fsblk_t ret; 627 628 memset(&ar, 0, sizeof(ar)); 629 /* Fill with neighbour allocated blocks */ 630 ar.inode = inode; 631 ar.goal = goal; 632 ar.len = count ? *count : 1; 633 ar.flags = flags; 634 635 ret = ext4_mb_new_blocks(handle, &ar, errp); 636 if (count) 637 *count = ar.len; 638 /* 639 * Account for the allocated meta blocks. We will never 640 * fail EDQUOT for metdata, but we do account for it. 641 */ 642 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 643 dquot_alloc_block_nofail(inode, 644 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 645 } 646 return ret; 647 } 648 649 /** 650 * ext4_count_free_clusters() -- count filesystem free clusters 651 * @sb: superblock 652 * 653 * Adds up the number of free clusters from each block group. 654 */ 655 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 656 { 657 ext4_fsblk_t desc_count; 658 struct ext4_group_desc *gdp; 659 ext4_group_t i; 660 ext4_group_t ngroups = ext4_get_groups_count(sb); 661 struct ext4_group_info *grp; 662 #ifdef EXT4FS_DEBUG 663 struct ext4_super_block *es; 664 ext4_fsblk_t bitmap_count; 665 unsigned int x; 666 struct buffer_head *bitmap_bh = NULL; 667 668 es = EXT4_SB(sb)->s_es; 669 desc_count = 0; 670 bitmap_count = 0; 671 gdp = NULL; 672 673 for (i = 0; i < ngroups; i++) { 674 gdp = ext4_get_group_desc(sb, i, NULL); 675 if (!gdp) 676 continue; 677 grp = NULL; 678 if (EXT4_SB(sb)->s_group_info) 679 grp = ext4_get_group_info(sb, i); 680 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 681 desc_count += ext4_free_group_clusters(sb, gdp); 682 brelse(bitmap_bh); 683 bitmap_bh = ext4_read_block_bitmap(sb, i); 684 if (bitmap_bh == NULL) 685 continue; 686 687 x = ext4_count_free(bitmap_bh->b_data, 688 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 689 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 690 i, ext4_free_group_clusters(sb, gdp), x); 691 bitmap_count += x; 692 } 693 brelse(bitmap_bh); 694 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 695 ", computed = %llu, %llu\n", 696 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 697 desc_count, bitmap_count); 698 return bitmap_count; 699 #else 700 desc_count = 0; 701 for (i = 0; i < ngroups; i++) { 702 gdp = ext4_get_group_desc(sb, i, NULL); 703 if (!gdp) 704 continue; 705 grp = NULL; 706 if (EXT4_SB(sb)->s_group_info) 707 grp = ext4_get_group_info(sb, i); 708 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 709 desc_count += ext4_free_group_clusters(sb, gdp); 710 } 711 712 return desc_count; 713 #endif 714 } 715 716 static inline int test_root(ext4_group_t a, int b) 717 { 718 while (1) { 719 if (a < b) 720 return 0; 721 if (a == b) 722 return 1; 723 if ((a % b) != 0) 724 return 0; 725 a = a / b; 726 } 727 } 728 729 /** 730 * ext4_bg_has_super - number of blocks used by the superblock in group 731 * @sb: superblock for filesystem 732 * @group: group number to check 733 * 734 * Return the number of blocks used by the superblock (primary or backup) 735 * in this group. Currently this will be only 0 or 1. 736 */ 737 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 738 { 739 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 740 741 if (group == 0) 742 return 1; 743 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_SPARSE_SUPER2)) { 744 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 745 group == le32_to_cpu(es->s_backup_bgs[1])) 746 return 1; 747 return 0; 748 } 749 if ((group <= 1) || !EXT4_HAS_RO_COMPAT_FEATURE(sb, 750 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) 751 return 1; 752 if (!(group & 1)) 753 return 0; 754 if (test_root(group, 3) || (test_root(group, 5)) || 755 test_root(group, 7)) 756 return 1; 757 758 return 0; 759 } 760 761 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 762 ext4_group_t group) 763 { 764 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 765 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 766 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 767 768 if (group == first || group == first + 1 || group == last) 769 return 1; 770 return 0; 771 } 772 773 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 774 ext4_group_t group) 775 { 776 if (!ext4_bg_has_super(sb, group)) 777 return 0; 778 779 if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG)) 780 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 781 else 782 return EXT4_SB(sb)->s_gdb_count; 783 } 784 785 /** 786 * ext4_bg_num_gdb - number of blocks used by the group table in group 787 * @sb: superblock for filesystem 788 * @group: group number to check 789 * 790 * Return the number of blocks used by the group descriptor table 791 * (primary or backup) in this group. In the future there may be a 792 * different number of descriptor blocks in each group. 793 */ 794 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 795 { 796 unsigned long first_meta_bg = 797 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 798 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 799 800 if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) || 801 metagroup < first_meta_bg) 802 return ext4_bg_num_gdb_nometa(sb, group); 803 804 return ext4_bg_num_gdb_meta(sb,group); 805 806 } 807 808 /* 809 * This function returns the number of file system metadata clusters at 810 * the beginning of a block group, including the reserved gdt blocks. 811 */ 812 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 813 ext4_group_t block_group) 814 { 815 struct ext4_sb_info *sbi = EXT4_SB(sb); 816 unsigned num; 817 818 /* Check for superblock and gdt backups in this group */ 819 num = ext4_bg_has_super(sb, block_group); 820 821 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) || 822 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 823 sbi->s_desc_per_block) { 824 if (num) { 825 num += ext4_bg_num_gdb(sb, block_group); 826 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 827 } 828 } else { /* For META_BG_BLOCK_GROUPS */ 829 num += ext4_bg_num_gdb(sb, block_group); 830 } 831 return EXT4_NUM_B2C(sbi, num); 832 } 833 /** 834 * ext4_inode_to_goal_block - return a hint for block allocation 835 * @inode: inode for block allocation 836 * 837 * Return the ideal location to start allocating blocks for a 838 * newly created inode. 839 */ 840 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 841 { 842 struct ext4_inode_info *ei = EXT4_I(inode); 843 ext4_group_t block_group; 844 ext4_grpblk_t colour; 845 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 846 ext4_fsblk_t bg_start; 847 ext4_fsblk_t last_block; 848 849 block_group = ei->i_block_group; 850 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 851 /* 852 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 853 * block groups per flexgroup, reserve the first block 854 * group for directories and special files. Regular 855 * files will start at the second block group. This 856 * tends to speed up directory access and improves 857 * fsck times. 858 */ 859 block_group &= ~(flex_size-1); 860 if (S_ISREG(inode->i_mode)) 861 block_group++; 862 } 863 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 864 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 865 866 /* 867 * If we are doing delayed allocation, we don't need take 868 * colour into account. 869 */ 870 if (test_opt(inode->i_sb, DELALLOC)) 871 return bg_start; 872 873 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 874 colour = (current->pid % 16) * 875 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 876 else 877 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 878 return bg_start + colour; 879 } 880 881