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 if ((bit_max >> 3) >= bh->b_size) 212 return -EFSCORRUPTED; 213 214 for (bit = 0; bit < bit_max; bit++) 215 ext4_set_bit(bit, bh->b_data); 216 217 start = ext4_group_first_block_no(sb, block_group); 218 219 if (ext4_has_feature_flex_bg(sb)) 220 flex_bg = 1; 221 222 /* Set bits for block and inode bitmaps, and inode table */ 223 tmp = ext4_block_bitmap(sb, gdp); 224 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 225 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 226 227 tmp = ext4_inode_bitmap(sb, gdp); 228 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 229 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 230 231 tmp = ext4_inode_table(sb, gdp); 232 for (; tmp < ext4_inode_table(sb, gdp) + 233 sbi->s_itb_per_group; tmp++) { 234 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) 235 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); 236 } 237 238 /* 239 * Also if the number of blocks within the group is less than 240 * the blocksize * 8 ( which is the size of bitmap ), set rest 241 * of the block bitmap to 1 242 */ 243 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), 244 sb->s_blocksize * 8, bh->b_data); 245 ext4_block_bitmap_csum_set(sb, block_group, gdp, bh); 246 ext4_group_desc_csum_set(sb, block_group, gdp); 247 return 0; 248 } 249 250 /* Return the number of free blocks in a block group. It is used when 251 * the block bitmap is uninitialized, so we can't just count the bits 252 * in the bitmap. */ 253 unsigned ext4_free_clusters_after_init(struct super_block *sb, 254 ext4_group_t block_group, 255 struct ext4_group_desc *gdp) 256 { 257 return num_clusters_in_group(sb, block_group) - 258 ext4_num_overhead_clusters(sb, block_group, gdp); 259 } 260 261 /* 262 * The free blocks are managed by bitmaps. A file system contains several 263 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 264 * block for inodes, N blocks for the inode table and data blocks. 265 * 266 * The file system contains group descriptors which are located after the 267 * super block. Each descriptor contains the number of the bitmap block and 268 * the free blocks count in the block. The descriptors are loaded in memory 269 * when a file system is mounted (see ext4_fill_super). 270 */ 271 272 /** 273 * ext4_get_group_desc() -- load group descriptor from disk 274 * @sb: super block 275 * @block_group: given block group 276 * @bh: pointer to the buffer head to store the block 277 * group descriptor 278 */ 279 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, 280 ext4_group_t block_group, 281 struct buffer_head **bh) 282 { 283 unsigned int group_desc; 284 unsigned int offset; 285 ext4_group_t ngroups = ext4_get_groups_count(sb); 286 struct ext4_group_desc *desc; 287 struct ext4_sb_info *sbi = EXT4_SB(sb); 288 289 if (block_group >= ngroups) { 290 ext4_error(sb, "block_group >= groups_count - block_group = %u," 291 " groups_count = %u", block_group, ngroups); 292 293 return NULL; 294 } 295 296 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 297 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 298 if (!sbi->s_group_desc[group_desc]) { 299 ext4_error(sb, "Group descriptor not loaded - " 300 "block_group = %u, group_desc = %u, desc = %u", 301 block_group, group_desc, offset); 302 return NULL; 303 } 304 305 desc = (struct ext4_group_desc *)( 306 (__u8 *)sbi->s_group_desc[group_desc]->b_data + 307 offset * EXT4_DESC_SIZE(sb)); 308 if (bh) 309 *bh = sbi->s_group_desc[group_desc]; 310 return desc; 311 } 312 313 /* 314 * Return the block number which was discovered to be invalid, or 0 if 315 * the block bitmap is valid. 316 */ 317 static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, 318 struct ext4_group_desc *desc, 319 ext4_group_t block_group, 320 struct buffer_head *bh) 321 { 322 struct ext4_sb_info *sbi = EXT4_SB(sb); 323 ext4_grpblk_t offset; 324 ext4_grpblk_t next_zero_bit; 325 ext4_fsblk_t blk; 326 ext4_fsblk_t group_first_block; 327 328 if (ext4_has_feature_flex_bg(sb)) { 329 /* with FLEX_BG, the inode/block bitmaps and itable 330 * blocks may not be in the group at all 331 * so the bitmap validation will be skipped for those groups 332 * or it has to also read the block group where the bitmaps 333 * are located to verify they are set. 334 */ 335 return 0; 336 } 337 group_first_block = ext4_group_first_block_no(sb, block_group); 338 339 /* check whether block bitmap block number is set */ 340 blk = ext4_block_bitmap(sb, desc); 341 offset = blk - group_first_block; 342 if (!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 (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) 350 /* bad block bitmap */ 351 return blk; 352 353 /* check whether the inode table block number is set */ 354 blk = ext4_inode_table(sb, desc); 355 offset = blk - group_first_block; 356 next_zero_bit = ext4_find_next_zero_bit(bh->b_data, 357 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group), 358 EXT4_B2C(sbi, offset)); 359 if (next_zero_bit < 360 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group)) 361 /* bad bitmap for inode tables */ 362 return blk; 363 return 0; 364 } 365 366 static int ext4_validate_block_bitmap(struct super_block *sb, 367 struct ext4_group_desc *desc, 368 ext4_group_t block_group, 369 struct buffer_head *bh) 370 { 371 ext4_fsblk_t blk; 372 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); 373 struct ext4_sb_info *sbi = EXT4_SB(sb); 374 375 if (buffer_verified(bh)) 376 return 0; 377 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 378 return -EFSCORRUPTED; 379 380 ext4_lock_group(sb, block_group); 381 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, 382 desc, bh))) { 383 ext4_unlock_group(sb, block_group); 384 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); 385 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 386 percpu_counter_sub(&sbi->s_freeclusters_counter, 387 grp->bb_free); 388 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 389 return -EFSBADCRC; 390 } 391 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); 392 if (unlikely(blk != 0)) { 393 ext4_unlock_group(sb, block_group); 394 ext4_error(sb, "bg %u: block %llu: invalid block bitmap", 395 block_group, blk); 396 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 397 percpu_counter_sub(&sbi->s_freeclusters_counter, 398 grp->bb_free); 399 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); 400 return -EFSCORRUPTED; 401 } 402 set_buffer_verified(bh); 403 ext4_unlock_group(sb, block_group); 404 return 0; 405 } 406 407 /** 408 * ext4_read_block_bitmap_nowait() 409 * @sb: super block 410 * @block_group: given block group 411 * 412 * Read the bitmap for a given block_group,and validate the 413 * bits for block/inode/inode tables are set in the bitmaps 414 * 415 * Return buffer_head on success or NULL in case of failure. 416 */ 417 struct buffer_head * 418 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) 419 { 420 struct ext4_group_desc *desc; 421 struct buffer_head *bh; 422 ext4_fsblk_t bitmap_blk; 423 int err; 424 425 desc = ext4_get_group_desc(sb, block_group, NULL); 426 if (!desc) 427 return ERR_PTR(-EFSCORRUPTED); 428 bitmap_blk = ext4_block_bitmap(sb, desc); 429 bh = sb_getblk(sb, bitmap_blk); 430 if (unlikely(!bh)) { 431 ext4_error(sb, "Cannot get buffer for block bitmap - " 432 "block_group = %u, block_bitmap = %llu", 433 block_group, bitmap_blk); 434 return ERR_PTR(-ENOMEM); 435 } 436 437 if (bitmap_uptodate(bh)) 438 goto verify; 439 440 lock_buffer(bh); 441 if (bitmap_uptodate(bh)) { 442 unlock_buffer(bh); 443 goto verify; 444 } 445 ext4_lock_group(sb, block_group); 446 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 447 err = ext4_init_block_bitmap(sb, bh, block_group, desc); 448 set_bitmap_uptodate(bh); 449 set_buffer_uptodate(bh); 450 ext4_unlock_group(sb, block_group); 451 unlock_buffer(bh); 452 if (err) { 453 ext4_error(sb, "Failed to init block bitmap for group " 454 "%u: %d", block_group, err); 455 goto out; 456 } 457 goto verify; 458 } 459 ext4_unlock_group(sb, block_group); 460 if (buffer_uptodate(bh)) { 461 /* 462 * if not uninit if bh is uptodate, 463 * bitmap is also uptodate 464 */ 465 set_bitmap_uptodate(bh); 466 unlock_buffer(bh); 467 goto verify; 468 } 469 /* 470 * submit the buffer_head for reading 471 */ 472 set_buffer_new(bh); 473 trace_ext4_read_block_bitmap_load(sb, block_group); 474 bh->b_end_io = ext4_end_bitmap_read; 475 get_bh(bh); 476 submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh); 477 return bh; 478 verify: 479 err = ext4_validate_block_bitmap(sb, desc, block_group, bh); 480 if (err) 481 goto out; 482 return bh; 483 out: 484 put_bh(bh); 485 return ERR_PTR(err); 486 } 487 488 /* Returns 0 on success, 1 on error */ 489 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, 490 struct buffer_head *bh) 491 { 492 struct ext4_group_desc *desc; 493 494 if (!buffer_new(bh)) 495 return 0; 496 desc = ext4_get_group_desc(sb, block_group, NULL); 497 if (!desc) 498 return -EFSCORRUPTED; 499 wait_on_buffer(bh); 500 if (!buffer_uptodate(bh)) { 501 ext4_error(sb, "Cannot read block bitmap - " 502 "block_group = %u, block_bitmap = %llu", 503 block_group, (unsigned long long) bh->b_blocknr); 504 return -EIO; 505 } 506 clear_buffer_new(bh); 507 /* Panic or remount fs read-only if block bitmap is invalid */ 508 return ext4_validate_block_bitmap(sb, desc, block_group, bh); 509 } 510 511 struct buffer_head * 512 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) 513 { 514 struct buffer_head *bh; 515 int err; 516 517 bh = ext4_read_block_bitmap_nowait(sb, block_group); 518 if (IS_ERR(bh)) 519 return bh; 520 err = ext4_wait_block_bitmap(sb, block_group, bh); 521 if (err) { 522 put_bh(bh); 523 return ERR_PTR(err); 524 } 525 return bh; 526 } 527 528 /** 529 * ext4_has_free_clusters() 530 * @sbi: in-core super block structure. 531 * @nclusters: number of needed blocks 532 * @flags: flags from ext4_mb_new_blocks() 533 * 534 * Check if filesystem has nclusters free & available for allocation. 535 * On success return 1, return 0 on failure. 536 */ 537 static int ext4_has_free_clusters(struct ext4_sb_info *sbi, 538 s64 nclusters, unsigned int flags) 539 { 540 s64 free_clusters, dirty_clusters, rsv, resv_clusters; 541 struct percpu_counter *fcc = &sbi->s_freeclusters_counter; 542 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; 543 544 free_clusters = percpu_counter_read_positive(fcc); 545 dirty_clusters = percpu_counter_read_positive(dcc); 546 resv_clusters = atomic64_read(&sbi->s_resv_clusters); 547 548 /* 549 * r_blocks_count should always be multiple of the cluster ratio so 550 * we are safe to do a plane bit shift only. 551 */ 552 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + 553 resv_clusters; 554 555 if (free_clusters - (nclusters + rsv + dirty_clusters) < 556 EXT4_FREECLUSTERS_WATERMARK) { 557 free_clusters = percpu_counter_sum_positive(fcc); 558 dirty_clusters = percpu_counter_sum_positive(dcc); 559 } 560 /* Check whether we have space after accounting for current 561 * dirty clusters & root reserved clusters. 562 */ 563 if (free_clusters >= (rsv + nclusters + dirty_clusters)) 564 return 1; 565 566 /* Hm, nope. Are (enough) root reserved clusters available? */ 567 if (uid_eq(sbi->s_resuid, current_fsuid()) || 568 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || 569 capable(CAP_SYS_RESOURCE) || 570 (flags & EXT4_MB_USE_ROOT_BLOCKS)) { 571 572 if (free_clusters >= (nclusters + dirty_clusters + 573 resv_clusters)) 574 return 1; 575 } 576 /* No free blocks. Let's see if we can dip into reserved pool */ 577 if (flags & EXT4_MB_USE_RESERVED) { 578 if (free_clusters >= (nclusters + dirty_clusters)) 579 return 1; 580 } 581 582 return 0; 583 } 584 585 int ext4_claim_free_clusters(struct ext4_sb_info *sbi, 586 s64 nclusters, unsigned int flags) 587 { 588 if (ext4_has_free_clusters(sbi, nclusters, flags)) { 589 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); 590 return 0; 591 } else 592 return -ENOSPC; 593 } 594 595 /** 596 * ext4_should_retry_alloc() 597 * @sb: super block 598 * @retries number of attemps has been made 599 * 600 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if 601 * it is profitable to retry the operation, this function will wait 602 * for the current or committing transaction to complete, and then 603 * return TRUE. 604 * 605 * if the total number of retries exceed three times, return FALSE. 606 */ 607 int ext4_should_retry_alloc(struct super_block *sb, int *retries) 608 { 609 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || 610 (*retries)++ > 3 || 611 !EXT4_SB(sb)->s_journal) 612 return 0; 613 614 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); 615 616 smp_mb(); 617 if (EXT4_SB(sb)->s_mb_free_pending) 618 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); 619 return 1; 620 } 621 622 /* 623 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks 624 * 625 * @handle: handle to this transaction 626 * @inode: file inode 627 * @goal: given target block(filesystem wide) 628 * @count: pointer to total number of clusters needed 629 * @errp: error code 630 * 631 * Return 1st allocated block number on success, *count stores total account 632 * error stores in errp pointer 633 */ 634 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, 635 ext4_fsblk_t goal, unsigned int flags, 636 unsigned long *count, int *errp) 637 { 638 struct ext4_allocation_request ar; 639 ext4_fsblk_t ret; 640 641 memset(&ar, 0, sizeof(ar)); 642 /* Fill with neighbour allocated blocks */ 643 ar.inode = inode; 644 ar.goal = goal; 645 ar.len = count ? *count : 1; 646 ar.flags = flags; 647 648 ret = ext4_mb_new_blocks(handle, &ar, errp); 649 if (count) 650 *count = ar.len; 651 /* 652 * Account for the allocated meta blocks. We will never 653 * fail EDQUOT for metdata, but we do account for it. 654 */ 655 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { 656 dquot_alloc_block_nofail(inode, 657 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); 658 } 659 return ret; 660 } 661 662 /** 663 * ext4_count_free_clusters() -- count filesystem free clusters 664 * @sb: superblock 665 * 666 * Adds up the number of free clusters from each block group. 667 */ 668 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) 669 { 670 ext4_fsblk_t desc_count; 671 struct ext4_group_desc *gdp; 672 ext4_group_t i; 673 ext4_group_t ngroups = ext4_get_groups_count(sb); 674 struct ext4_group_info *grp; 675 #ifdef EXT4FS_DEBUG 676 struct ext4_super_block *es; 677 ext4_fsblk_t bitmap_count; 678 unsigned int x; 679 struct buffer_head *bitmap_bh = NULL; 680 681 es = EXT4_SB(sb)->s_es; 682 desc_count = 0; 683 bitmap_count = 0; 684 gdp = NULL; 685 686 for (i = 0; i < ngroups; i++) { 687 gdp = ext4_get_group_desc(sb, i, NULL); 688 if (!gdp) 689 continue; 690 grp = NULL; 691 if (EXT4_SB(sb)->s_group_info) 692 grp = ext4_get_group_info(sb, i); 693 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 694 desc_count += ext4_free_group_clusters(sb, gdp); 695 brelse(bitmap_bh); 696 bitmap_bh = ext4_read_block_bitmap(sb, i); 697 if (IS_ERR(bitmap_bh)) { 698 bitmap_bh = NULL; 699 continue; 700 } 701 702 x = ext4_count_free(bitmap_bh->b_data, 703 EXT4_CLUSTERS_PER_GROUP(sb) / 8); 704 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", 705 i, ext4_free_group_clusters(sb, gdp), x); 706 bitmap_count += x; 707 } 708 brelse(bitmap_bh); 709 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" 710 ", computed = %llu, %llu\n", 711 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), 712 desc_count, bitmap_count); 713 return bitmap_count; 714 #else 715 desc_count = 0; 716 for (i = 0; i < ngroups; i++) { 717 gdp = ext4_get_group_desc(sb, i, NULL); 718 if (!gdp) 719 continue; 720 grp = NULL; 721 if (EXT4_SB(sb)->s_group_info) 722 grp = ext4_get_group_info(sb, i); 723 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) 724 desc_count += ext4_free_group_clusters(sb, gdp); 725 } 726 727 return desc_count; 728 #endif 729 } 730 731 static inline int test_root(ext4_group_t a, int b) 732 { 733 while (1) { 734 if (a < b) 735 return 0; 736 if (a == b) 737 return 1; 738 if ((a % b) != 0) 739 return 0; 740 a = a / b; 741 } 742 } 743 744 /** 745 * ext4_bg_has_super - number of blocks used by the superblock in group 746 * @sb: superblock for filesystem 747 * @group: group number to check 748 * 749 * Return the number of blocks used by the superblock (primary or backup) 750 * in this group. Currently this will be only 0 or 1. 751 */ 752 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) 753 { 754 struct ext4_super_block *es = EXT4_SB(sb)->s_es; 755 756 if (group == 0) 757 return 1; 758 if (ext4_has_feature_sparse_super2(sb)) { 759 if (group == le32_to_cpu(es->s_backup_bgs[0]) || 760 group == le32_to_cpu(es->s_backup_bgs[1])) 761 return 1; 762 return 0; 763 } 764 if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) 765 return 1; 766 if (!(group & 1)) 767 return 0; 768 if (test_root(group, 3) || (test_root(group, 5)) || 769 test_root(group, 7)) 770 return 1; 771 772 return 0; 773 } 774 775 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, 776 ext4_group_t group) 777 { 778 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 779 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); 780 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; 781 782 if (group == first || group == first + 1 || group == last) 783 return 1; 784 return 0; 785 } 786 787 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, 788 ext4_group_t group) 789 { 790 if (!ext4_bg_has_super(sb, group)) 791 return 0; 792 793 if (ext4_has_feature_meta_bg(sb)) 794 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 795 else 796 return EXT4_SB(sb)->s_gdb_count; 797 } 798 799 /** 800 * ext4_bg_num_gdb - number of blocks used by the group table in group 801 * @sb: superblock for filesystem 802 * @group: group number to check 803 * 804 * Return the number of blocks used by the group descriptor table 805 * (primary or backup) in this group. In the future there may be a 806 * different number of descriptor blocks in each group. 807 */ 808 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) 809 { 810 unsigned long first_meta_bg = 811 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); 812 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); 813 814 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) 815 return ext4_bg_num_gdb_nometa(sb, group); 816 817 return ext4_bg_num_gdb_meta(sb,group); 818 819 } 820 821 /* 822 * This function returns the number of file system metadata clusters at 823 * the beginning of a block group, including the reserved gdt blocks. 824 */ 825 static unsigned ext4_num_base_meta_clusters(struct super_block *sb, 826 ext4_group_t block_group) 827 { 828 struct ext4_sb_info *sbi = EXT4_SB(sb); 829 unsigned num; 830 831 /* Check for superblock and gdt backups in this group */ 832 num = ext4_bg_has_super(sb, block_group); 833 834 if (!ext4_has_feature_meta_bg(sb) || 835 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * 836 sbi->s_desc_per_block) { 837 if (num) { 838 num += ext4_bg_num_gdb(sb, block_group); 839 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 840 } 841 } else { /* For META_BG_BLOCK_GROUPS */ 842 num += ext4_bg_num_gdb(sb, block_group); 843 } 844 return EXT4_NUM_B2C(sbi, num); 845 } 846 /** 847 * ext4_inode_to_goal_block - return a hint for block allocation 848 * @inode: inode for block allocation 849 * 850 * Return the ideal location to start allocating blocks for a 851 * newly created inode. 852 */ 853 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) 854 { 855 struct ext4_inode_info *ei = EXT4_I(inode); 856 ext4_group_t block_group; 857 ext4_grpblk_t colour; 858 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 859 ext4_fsblk_t bg_start; 860 ext4_fsblk_t last_block; 861 862 block_group = ei->i_block_group; 863 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 864 /* 865 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 866 * block groups per flexgroup, reserve the first block 867 * group for directories and special files. Regular 868 * files will start at the second block group. This 869 * tends to speed up directory access and improves 870 * fsck times. 871 */ 872 block_group &= ~(flex_size-1); 873 if (S_ISREG(inode->i_mode)) 874 block_group++; 875 } 876 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 877 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 878 879 /* 880 * If we are doing delayed allocation, we don't need take 881 * colour into account. 882 */ 883 if (test_opt(inode->i_sb, DELALLOC)) 884 return bg_start; 885 886 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 887 colour = (current->pid % 16) * 888 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 889 else 890 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 891 return bg_start + colour; 892 } 893 894