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