1 /* 2 * linux/fs/ext4/ialloc.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 * BSD ufs-inspired inode and directory allocation by 10 * Stephen Tweedie (sct@redhat.com), 1993 11 * Big-endian to little-endian byte-swapping/bitmaps by 12 * David S. Miller (davem@caip.rutgers.edu), 1995 13 */ 14 15 #include <linux/time.h> 16 #include <linux/fs.h> 17 #include <linux/jbd2.h> 18 #include <linux/stat.h> 19 #include <linux/string.h> 20 #include <linux/quotaops.h> 21 #include <linux/buffer_head.h> 22 #include <linux/random.h> 23 #include <linux/bitops.h> 24 #include <linux/blkdev.h> 25 #include <asm/byteorder.h> 26 27 #include "ext4.h" 28 #include "ext4_jbd2.h" 29 #include "xattr.h" 30 #include "acl.h" 31 32 #include <trace/events/ext4.h> 33 34 /* 35 * ialloc.c contains the inodes allocation and deallocation routines 36 */ 37 38 /* 39 * The free inodes are managed by bitmaps. A file system contains several 40 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 41 * block for inodes, N blocks for the inode table and data blocks. 42 * 43 * The file system contains group descriptors which are located after the 44 * super block. Each descriptor contains the number of the bitmap block and 45 * the free blocks count in the block. 46 */ 47 48 /* 49 * To avoid calling the atomic setbit hundreds or thousands of times, we only 50 * need to use it within a single byte (to ensure we get endianness right). 51 * We can use memset for the rest of the bitmap as there are no other users. 52 */ 53 void mark_bitmap_end(int start_bit, int end_bit, char *bitmap) 54 { 55 int i; 56 57 if (start_bit >= end_bit) 58 return; 59 60 ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit); 61 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++) 62 ext4_set_bit(i, bitmap); 63 if (i < end_bit) 64 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3); 65 } 66 67 /* Initializes an uninitialized inode bitmap */ 68 unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh, 69 ext4_group_t block_group, 70 struct ext4_group_desc *gdp) 71 { 72 struct ext4_sb_info *sbi = EXT4_SB(sb); 73 74 J_ASSERT_BH(bh, buffer_locked(bh)); 75 76 /* If checksum is bad mark all blocks and inodes use to prevent 77 * allocation, essentially implementing a per-group read-only flag. */ 78 if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) { 79 ext4_error(sb, "Checksum bad for group %u", block_group); 80 ext4_free_blks_set(sb, gdp, 0); 81 ext4_free_inodes_set(sb, gdp, 0); 82 ext4_itable_unused_set(sb, gdp, 0); 83 memset(bh->b_data, 0xff, sb->s_blocksize); 84 return 0; 85 } 86 87 memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8); 88 mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8, 89 bh->b_data); 90 91 return EXT4_INODES_PER_GROUP(sb); 92 } 93 94 /* 95 * Read the inode allocation bitmap for a given block_group, reading 96 * into the specified slot in the superblock's bitmap cache. 97 * 98 * Return buffer_head of bitmap on success or NULL. 99 */ 100 static struct buffer_head * 101 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) 102 { 103 struct ext4_group_desc *desc; 104 struct buffer_head *bh = NULL; 105 ext4_fsblk_t bitmap_blk; 106 107 desc = ext4_get_group_desc(sb, block_group, NULL); 108 if (!desc) 109 return NULL; 110 bitmap_blk = ext4_inode_bitmap(sb, desc); 111 bh = sb_getblk(sb, bitmap_blk); 112 if (unlikely(!bh)) { 113 ext4_error(sb, "Cannot read inode bitmap - " 114 "block_group = %u, inode_bitmap = %llu", 115 block_group, bitmap_blk); 116 return NULL; 117 } 118 if (bitmap_uptodate(bh)) 119 return bh; 120 121 lock_buffer(bh); 122 if (bitmap_uptodate(bh)) { 123 unlock_buffer(bh); 124 return bh; 125 } 126 ext4_lock_group(sb, block_group); 127 if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) { 128 ext4_init_inode_bitmap(sb, bh, block_group, desc); 129 set_bitmap_uptodate(bh); 130 set_buffer_uptodate(bh); 131 ext4_unlock_group(sb, block_group); 132 unlock_buffer(bh); 133 return bh; 134 } 135 ext4_unlock_group(sb, block_group); 136 if (buffer_uptodate(bh)) { 137 /* 138 * if not uninit if bh is uptodate, 139 * bitmap is also uptodate 140 */ 141 set_bitmap_uptodate(bh); 142 unlock_buffer(bh); 143 return bh; 144 } 145 /* 146 * submit the buffer_head for read. We can 147 * safely mark the bitmap as uptodate now. 148 * We do it here so the bitmap uptodate bit 149 * get set with buffer lock held. 150 */ 151 set_bitmap_uptodate(bh); 152 if (bh_submit_read(bh) < 0) { 153 put_bh(bh); 154 ext4_error(sb, "Cannot read inode bitmap - " 155 "block_group = %u, inode_bitmap = %llu", 156 block_group, bitmap_blk); 157 return NULL; 158 } 159 return bh; 160 } 161 162 /* 163 * NOTE! When we get the inode, we're the only people 164 * that have access to it, and as such there are no 165 * race conditions we have to worry about. The inode 166 * is not on the hash-lists, and it cannot be reached 167 * through the filesystem because the directory entry 168 * has been deleted earlier. 169 * 170 * HOWEVER: we must make sure that we get no aliases, 171 * which means that we have to call "clear_inode()" 172 * _before_ we mark the inode not in use in the inode 173 * bitmaps. Otherwise a newly created file might use 174 * the same inode number (not actually the same pointer 175 * though), and then we'd have two inodes sharing the 176 * same inode number and space on the harddisk. 177 */ 178 void ext4_free_inode(handle_t *handle, struct inode *inode) 179 { 180 struct super_block *sb = inode->i_sb; 181 int is_directory; 182 unsigned long ino; 183 struct buffer_head *bitmap_bh = NULL; 184 struct buffer_head *bh2; 185 ext4_group_t block_group; 186 unsigned long bit; 187 struct ext4_group_desc *gdp; 188 struct ext4_super_block *es; 189 struct ext4_sb_info *sbi; 190 int fatal = 0, err, count, cleared; 191 192 if (atomic_read(&inode->i_count) > 1) { 193 printk(KERN_ERR "ext4_free_inode: inode has count=%d\n", 194 atomic_read(&inode->i_count)); 195 return; 196 } 197 if (inode->i_nlink) { 198 printk(KERN_ERR "ext4_free_inode: inode has nlink=%d\n", 199 inode->i_nlink); 200 return; 201 } 202 if (!sb) { 203 printk(KERN_ERR "ext4_free_inode: inode on " 204 "nonexistent device\n"); 205 return; 206 } 207 sbi = EXT4_SB(sb); 208 209 ino = inode->i_ino; 210 ext4_debug("freeing inode %lu\n", ino); 211 trace_ext4_free_inode(inode); 212 213 /* 214 * Note: we must free any quota before locking the superblock, 215 * as writing the quota to disk may need the lock as well. 216 */ 217 dquot_initialize(inode); 218 ext4_xattr_delete_inode(handle, inode); 219 dquot_free_inode(inode); 220 dquot_drop(inode); 221 222 is_directory = S_ISDIR(inode->i_mode); 223 224 /* Do this BEFORE marking the inode not in use or returning an error */ 225 clear_inode(inode); 226 227 es = EXT4_SB(sb)->s_es; 228 if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) { 229 ext4_error(sb, "reserved or nonexistent inode %lu", ino); 230 goto error_return; 231 } 232 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb); 233 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb); 234 bitmap_bh = ext4_read_inode_bitmap(sb, block_group); 235 if (!bitmap_bh) 236 goto error_return; 237 238 BUFFER_TRACE(bitmap_bh, "get_write_access"); 239 fatal = ext4_journal_get_write_access(handle, bitmap_bh); 240 if (fatal) 241 goto error_return; 242 243 /* Ok, now we can actually update the inode bitmaps.. */ 244 cleared = ext4_clear_bit_atomic(ext4_group_lock_ptr(sb, block_group), 245 bit, bitmap_bh->b_data); 246 if (!cleared) 247 ext4_error(sb, "bit already cleared for inode %lu", ino); 248 else { 249 gdp = ext4_get_group_desc(sb, block_group, &bh2); 250 251 BUFFER_TRACE(bh2, "get_write_access"); 252 fatal = ext4_journal_get_write_access(handle, bh2); 253 if (fatal) goto error_return; 254 255 if (gdp) { 256 ext4_lock_group(sb, block_group); 257 count = ext4_free_inodes_count(sb, gdp) + 1; 258 ext4_free_inodes_set(sb, gdp, count); 259 if (is_directory) { 260 count = ext4_used_dirs_count(sb, gdp) - 1; 261 ext4_used_dirs_set(sb, gdp, count); 262 if (sbi->s_log_groups_per_flex) { 263 ext4_group_t f; 264 265 f = ext4_flex_group(sbi, block_group); 266 atomic_dec(&sbi->s_flex_groups[f].used_dirs); 267 } 268 269 } 270 gdp->bg_checksum = ext4_group_desc_csum(sbi, 271 block_group, gdp); 272 ext4_unlock_group(sb, block_group); 273 percpu_counter_inc(&sbi->s_freeinodes_counter); 274 if (is_directory) 275 percpu_counter_dec(&sbi->s_dirs_counter); 276 277 if (sbi->s_log_groups_per_flex) { 278 ext4_group_t f; 279 280 f = ext4_flex_group(sbi, block_group); 281 atomic_inc(&sbi->s_flex_groups[f].free_inodes); 282 } 283 } 284 BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata"); 285 err = ext4_handle_dirty_metadata(handle, NULL, bh2); 286 if (!fatal) fatal = err; 287 } 288 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata"); 289 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh); 290 if (!fatal) 291 fatal = err; 292 sb->s_dirt = 1; 293 error_return: 294 brelse(bitmap_bh); 295 ext4_std_error(sb, fatal); 296 } 297 298 /* 299 * There are two policies for allocating an inode. If the new inode is 300 * a directory, then a forward search is made for a block group with both 301 * free space and a low directory-to-inode ratio; if that fails, then of 302 * the groups with above-average free space, that group with the fewest 303 * directories already is chosen. 304 * 305 * For other inodes, search forward from the parent directory\'s block 306 * group to find a free inode. 307 */ 308 static int find_group_dir(struct super_block *sb, struct inode *parent, 309 ext4_group_t *best_group) 310 { 311 ext4_group_t ngroups = ext4_get_groups_count(sb); 312 unsigned int freei, avefreei; 313 struct ext4_group_desc *desc, *best_desc = NULL; 314 ext4_group_t group; 315 int ret = -1; 316 317 freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter); 318 avefreei = freei / ngroups; 319 320 for (group = 0; group < ngroups; group++) { 321 desc = ext4_get_group_desc(sb, group, NULL); 322 if (!desc || !ext4_free_inodes_count(sb, desc)) 323 continue; 324 if (ext4_free_inodes_count(sb, desc) < avefreei) 325 continue; 326 if (!best_desc || 327 (ext4_free_blks_count(sb, desc) > 328 ext4_free_blks_count(sb, best_desc))) { 329 *best_group = group; 330 best_desc = desc; 331 ret = 0; 332 } 333 } 334 return ret; 335 } 336 337 #define free_block_ratio 10 338 339 static int find_group_flex(struct super_block *sb, struct inode *parent, 340 ext4_group_t *best_group) 341 { 342 struct ext4_sb_info *sbi = EXT4_SB(sb); 343 struct ext4_group_desc *desc; 344 struct flex_groups *flex_group = sbi->s_flex_groups; 345 ext4_group_t parent_group = EXT4_I(parent)->i_block_group; 346 ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group); 347 ext4_group_t ngroups = ext4_get_groups_count(sb); 348 int flex_size = ext4_flex_bg_size(sbi); 349 ext4_group_t best_flex = parent_fbg_group; 350 int blocks_per_flex = sbi->s_blocks_per_group * flex_size; 351 int flexbg_free_blocks; 352 int flex_freeb_ratio; 353 ext4_group_t n_fbg_groups; 354 ext4_group_t i; 355 356 n_fbg_groups = (ngroups + flex_size - 1) >> 357 sbi->s_log_groups_per_flex; 358 359 find_close_to_parent: 360 flexbg_free_blocks = atomic_read(&flex_group[best_flex].free_blocks); 361 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex; 362 if (atomic_read(&flex_group[best_flex].free_inodes) && 363 flex_freeb_ratio > free_block_ratio) 364 goto found_flexbg; 365 366 if (best_flex && best_flex == parent_fbg_group) { 367 best_flex--; 368 goto find_close_to_parent; 369 } 370 371 for (i = 0; i < n_fbg_groups; i++) { 372 if (i == parent_fbg_group || i == parent_fbg_group - 1) 373 continue; 374 375 flexbg_free_blocks = atomic_read(&flex_group[i].free_blocks); 376 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex; 377 378 if (flex_freeb_ratio > free_block_ratio && 379 (atomic_read(&flex_group[i].free_inodes))) { 380 best_flex = i; 381 goto found_flexbg; 382 } 383 384 if ((atomic_read(&flex_group[best_flex].free_inodes) == 0) || 385 ((atomic_read(&flex_group[i].free_blocks) > 386 atomic_read(&flex_group[best_flex].free_blocks)) && 387 atomic_read(&flex_group[i].free_inodes))) 388 best_flex = i; 389 } 390 391 if (!atomic_read(&flex_group[best_flex].free_inodes) || 392 !atomic_read(&flex_group[best_flex].free_blocks)) 393 return -1; 394 395 found_flexbg: 396 for (i = best_flex * flex_size; i < ngroups && 397 i < (best_flex + 1) * flex_size; i++) { 398 desc = ext4_get_group_desc(sb, i, NULL); 399 if (ext4_free_inodes_count(sb, desc)) { 400 *best_group = i; 401 goto out; 402 } 403 } 404 405 return -1; 406 out: 407 return 0; 408 } 409 410 struct orlov_stats { 411 __u32 free_inodes; 412 __u32 free_blocks; 413 __u32 used_dirs; 414 }; 415 416 /* 417 * Helper function for Orlov's allocator; returns critical information 418 * for a particular block group or flex_bg. If flex_size is 1, then g 419 * is a block group number; otherwise it is flex_bg number. 420 */ 421 void get_orlov_stats(struct super_block *sb, ext4_group_t g, 422 int flex_size, struct orlov_stats *stats) 423 { 424 struct ext4_group_desc *desc; 425 struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups; 426 427 if (flex_size > 1) { 428 stats->free_inodes = atomic_read(&flex_group[g].free_inodes); 429 stats->free_blocks = atomic_read(&flex_group[g].free_blocks); 430 stats->used_dirs = atomic_read(&flex_group[g].used_dirs); 431 return; 432 } 433 434 desc = ext4_get_group_desc(sb, g, NULL); 435 if (desc) { 436 stats->free_inodes = ext4_free_inodes_count(sb, desc); 437 stats->free_blocks = ext4_free_blks_count(sb, desc); 438 stats->used_dirs = ext4_used_dirs_count(sb, desc); 439 } else { 440 stats->free_inodes = 0; 441 stats->free_blocks = 0; 442 stats->used_dirs = 0; 443 } 444 } 445 446 /* 447 * Orlov's allocator for directories. 448 * 449 * We always try to spread first-level directories. 450 * 451 * If there are blockgroups with both free inodes and free blocks counts 452 * not worse than average we return one with smallest directory count. 453 * Otherwise we simply return a random group. 454 * 455 * For the rest rules look so: 456 * 457 * It's OK to put directory into a group unless 458 * it has too many directories already (max_dirs) or 459 * it has too few free inodes left (min_inodes) or 460 * it has too few free blocks left (min_blocks) or 461 * Parent's group is preferred, if it doesn't satisfy these 462 * conditions we search cyclically through the rest. If none 463 * of the groups look good we just look for a group with more 464 * free inodes than average (starting at parent's group). 465 */ 466 467 static int find_group_orlov(struct super_block *sb, struct inode *parent, 468 ext4_group_t *group, int mode, 469 const struct qstr *qstr) 470 { 471 ext4_group_t parent_group = EXT4_I(parent)->i_block_group; 472 struct ext4_sb_info *sbi = EXT4_SB(sb); 473 ext4_group_t real_ngroups = ext4_get_groups_count(sb); 474 int inodes_per_group = EXT4_INODES_PER_GROUP(sb); 475 unsigned int freei, avefreei; 476 ext4_fsblk_t freeb, avefreeb; 477 unsigned int ndirs; 478 int max_dirs, min_inodes; 479 ext4_grpblk_t min_blocks; 480 ext4_group_t i, grp, g, ngroups; 481 struct ext4_group_desc *desc; 482 struct orlov_stats stats; 483 int flex_size = ext4_flex_bg_size(sbi); 484 struct dx_hash_info hinfo; 485 486 ngroups = real_ngroups; 487 if (flex_size > 1) { 488 ngroups = (real_ngroups + flex_size - 1) >> 489 sbi->s_log_groups_per_flex; 490 parent_group >>= sbi->s_log_groups_per_flex; 491 } 492 493 freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter); 494 avefreei = freei / ngroups; 495 freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter); 496 avefreeb = freeb; 497 do_div(avefreeb, ngroups); 498 ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter); 499 500 if (S_ISDIR(mode) && 501 ((parent == sb->s_root->d_inode) || 502 (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL))) { 503 int best_ndir = inodes_per_group; 504 int ret = -1; 505 506 if (qstr) { 507 hinfo.hash_version = DX_HASH_HALF_MD4; 508 hinfo.seed = sbi->s_hash_seed; 509 ext4fs_dirhash(qstr->name, qstr->len, &hinfo); 510 grp = hinfo.hash; 511 } else 512 get_random_bytes(&grp, sizeof(grp)); 513 parent_group = (unsigned)grp % ngroups; 514 for (i = 0; i < ngroups; i++) { 515 g = (parent_group + i) % ngroups; 516 get_orlov_stats(sb, g, flex_size, &stats); 517 if (!stats.free_inodes) 518 continue; 519 if (stats.used_dirs >= best_ndir) 520 continue; 521 if (stats.free_inodes < avefreei) 522 continue; 523 if (stats.free_blocks < avefreeb) 524 continue; 525 grp = g; 526 ret = 0; 527 best_ndir = stats.used_dirs; 528 } 529 if (ret) 530 goto fallback; 531 found_flex_bg: 532 if (flex_size == 1) { 533 *group = grp; 534 return 0; 535 } 536 537 /* 538 * We pack inodes at the beginning of the flexgroup's 539 * inode tables. Block allocation decisions will do 540 * something similar, although regular files will 541 * start at 2nd block group of the flexgroup. See 542 * ext4_ext_find_goal() and ext4_find_near(). 543 */ 544 grp *= flex_size; 545 for (i = 0; i < flex_size; i++) { 546 if (grp+i >= real_ngroups) 547 break; 548 desc = ext4_get_group_desc(sb, grp+i, NULL); 549 if (desc && ext4_free_inodes_count(sb, desc)) { 550 *group = grp+i; 551 return 0; 552 } 553 } 554 goto fallback; 555 } 556 557 max_dirs = ndirs / ngroups + inodes_per_group / 16; 558 min_inodes = avefreei - inodes_per_group*flex_size / 4; 559 if (min_inodes < 1) 560 min_inodes = 1; 561 min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb)*flex_size / 4; 562 563 /* 564 * Start looking in the flex group where we last allocated an 565 * inode for this parent directory 566 */ 567 if (EXT4_I(parent)->i_last_alloc_group != ~0) { 568 parent_group = EXT4_I(parent)->i_last_alloc_group; 569 if (flex_size > 1) 570 parent_group >>= sbi->s_log_groups_per_flex; 571 } 572 573 for (i = 0; i < ngroups; i++) { 574 grp = (parent_group + i) % ngroups; 575 get_orlov_stats(sb, grp, flex_size, &stats); 576 if (stats.used_dirs >= max_dirs) 577 continue; 578 if (stats.free_inodes < min_inodes) 579 continue; 580 if (stats.free_blocks < min_blocks) 581 continue; 582 goto found_flex_bg; 583 } 584 585 fallback: 586 ngroups = real_ngroups; 587 avefreei = freei / ngroups; 588 fallback_retry: 589 parent_group = EXT4_I(parent)->i_block_group; 590 for (i = 0; i < ngroups; i++) { 591 grp = (parent_group + i) % ngroups; 592 desc = ext4_get_group_desc(sb, grp, NULL); 593 if (desc && ext4_free_inodes_count(sb, desc) && 594 ext4_free_inodes_count(sb, desc) >= avefreei) { 595 *group = grp; 596 return 0; 597 } 598 } 599 600 if (avefreei) { 601 /* 602 * The free-inodes counter is approximate, and for really small 603 * filesystems the above test can fail to find any blockgroups 604 */ 605 avefreei = 0; 606 goto fallback_retry; 607 } 608 609 return -1; 610 } 611 612 static int find_group_other(struct super_block *sb, struct inode *parent, 613 ext4_group_t *group, int mode) 614 { 615 ext4_group_t parent_group = EXT4_I(parent)->i_block_group; 616 ext4_group_t i, last, ngroups = ext4_get_groups_count(sb); 617 struct ext4_group_desc *desc; 618 int flex_size = ext4_flex_bg_size(EXT4_SB(sb)); 619 620 /* 621 * Try to place the inode is the same flex group as its 622 * parent. If we can't find space, use the Orlov algorithm to 623 * find another flex group, and store that information in the 624 * parent directory's inode information so that use that flex 625 * group for future allocations. 626 */ 627 if (flex_size > 1) { 628 int retry = 0; 629 630 try_again: 631 parent_group &= ~(flex_size-1); 632 last = parent_group + flex_size; 633 if (last > ngroups) 634 last = ngroups; 635 for (i = parent_group; i < last; i++) { 636 desc = ext4_get_group_desc(sb, i, NULL); 637 if (desc && ext4_free_inodes_count(sb, desc)) { 638 *group = i; 639 return 0; 640 } 641 } 642 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) { 643 retry = 1; 644 parent_group = EXT4_I(parent)->i_last_alloc_group; 645 goto try_again; 646 } 647 /* 648 * If this didn't work, use the Orlov search algorithm 649 * to find a new flex group; we pass in the mode to 650 * avoid the topdir algorithms. 651 */ 652 *group = parent_group + flex_size; 653 if (*group > ngroups) 654 *group = 0; 655 return find_group_orlov(sb, parent, group, mode, 0); 656 } 657 658 /* 659 * Try to place the inode in its parent directory 660 */ 661 *group = parent_group; 662 desc = ext4_get_group_desc(sb, *group, NULL); 663 if (desc && ext4_free_inodes_count(sb, desc) && 664 ext4_free_blks_count(sb, desc)) 665 return 0; 666 667 /* 668 * We're going to place this inode in a different blockgroup from its 669 * parent. We want to cause files in a common directory to all land in 670 * the same blockgroup. But we want files which are in a different 671 * directory which shares a blockgroup with our parent to land in a 672 * different blockgroup. 673 * 674 * So add our directory's i_ino into the starting point for the hash. 675 */ 676 *group = (*group + parent->i_ino) % ngroups; 677 678 /* 679 * Use a quadratic hash to find a group with a free inode and some free 680 * blocks. 681 */ 682 for (i = 1; i < ngroups; i <<= 1) { 683 *group += i; 684 if (*group >= ngroups) 685 *group -= ngroups; 686 desc = ext4_get_group_desc(sb, *group, NULL); 687 if (desc && ext4_free_inodes_count(sb, desc) && 688 ext4_free_blks_count(sb, desc)) 689 return 0; 690 } 691 692 /* 693 * That failed: try linear search for a free inode, even if that group 694 * has no free blocks. 695 */ 696 *group = parent_group; 697 for (i = 0; i < ngroups; i++) { 698 if (++*group >= ngroups) 699 *group = 0; 700 desc = ext4_get_group_desc(sb, *group, NULL); 701 if (desc && ext4_free_inodes_count(sb, desc)) 702 return 0; 703 } 704 705 return -1; 706 } 707 708 /* 709 * claim the inode from the inode bitmap. If the group 710 * is uninit we need to take the groups's ext4_group_lock 711 * and clear the uninit flag. The inode bitmap update 712 * and group desc uninit flag clear should be done 713 * after holding ext4_group_lock so that ext4_read_inode_bitmap 714 * doesn't race with the ext4_claim_inode 715 */ 716 static int ext4_claim_inode(struct super_block *sb, 717 struct buffer_head *inode_bitmap_bh, 718 unsigned long ino, ext4_group_t group, int mode) 719 { 720 int free = 0, retval = 0, count; 721 struct ext4_sb_info *sbi = EXT4_SB(sb); 722 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL); 723 724 ext4_lock_group(sb, group); 725 if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) { 726 /* not a free inode */ 727 retval = 1; 728 goto err_ret; 729 } 730 ino++; 731 if ((group == 0 && ino < EXT4_FIRST_INO(sb)) || 732 ino > EXT4_INODES_PER_GROUP(sb)) { 733 ext4_unlock_group(sb, group); 734 ext4_error(sb, "reserved inode or inode > inodes count - " 735 "block_group = %u, inode=%lu", group, 736 ino + group * EXT4_INODES_PER_GROUP(sb)); 737 return 1; 738 } 739 /* If we didn't allocate from within the initialized part of the inode 740 * table then we need to initialize up to this inode. */ 741 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { 742 743 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) { 744 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT); 745 /* When marking the block group with 746 * ~EXT4_BG_INODE_UNINIT we don't want to depend 747 * on the value of bg_itable_unused even though 748 * mke2fs could have initialized the same for us. 749 * Instead we calculated the value below 750 */ 751 752 free = 0; 753 } else { 754 free = EXT4_INODES_PER_GROUP(sb) - 755 ext4_itable_unused_count(sb, gdp); 756 } 757 758 /* 759 * Check the relative inode number against the last used 760 * relative inode number in this group. if it is greater 761 * we need to update the bg_itable_unused count 762 * 763 */ 764 if (ino > free) 765 ext4_itable_unused_set(sb, gdp, 766 (EXT4_INODES_PER_GROUP(sb) - ino)); 767 } 768 count = ext4_free_inodes_count(sb, gdp) - 1; 769 ext4_free_inodes_set(sb, gdp, count); 770 if (S_ISDIR(mode)) { 771 count = ext4_used_dirs_count(sb, gdp) + 1; 772 ext4_used_dirs_set(sb, gdp, count); 773 if (sbi->s_log_groups_per_flex) { 774 ext4_group_t f = ext4_flex_group(sbi, group); 775 776 atomic_inc(&sbi->s_flex_groups[f].used_dirs); 777 } 778 } 779 gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp); 780 err_ret: 781 ext4_unlock_group(sb, group); 782 return retval; 783 } 784 785 /* 786 * There are two policies for allocating an inode. If the new inode is 787 * a directory, then a forward search is made for a block group with both 788 * free space and a low directory-to-inode ratio; if that fails, then of 789 * the groups with above-average free space, that group with the fewest 790 * directories already is chosen. 791 * 792 * For other inodes, search forward from the parent directory's block 793 * group to find a free inode. 794 */ 795 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode, 796 const struct qstr *qstr, __u32 goal) 797 { 798 struct super_block *sb; 799 struct buffer_head *inode_bitmap_bh = NULL; 800 struct buffer_head *group_desc_bh; 801 ext4_group_t ngroups, group = 0; 802 unsigned long ino = 0; 803 struct inode *inode; 804 struct ext4_group_desc *gdp = NULL; 805 struct ext4_inode_info *ei; 806 struct ext4_sb_info *sbi; 807 int ret2, err = 0; 808 struct inode *ret; 809 ext4_group_t i; 810 int free = 0; 811 static int once = 1; 812 ext4_group_t flex_group; 813 814 /* Cannot create files in a deleted directory */ 815 if (!dir || !dir->i_nlink) 816 return ERR_PTR(-EPERM); 817 818 sb = dir->i_sb; 819 ngroups = ext4_get_groups_count(sb); 820 trace_ext4_request_inode(dir, mode); 821 inode = new_inode(sb); 822 if (!inode) 823 return ERR_PTR(-ENOMEM); 824 ei = EXT4_I(inode); 825 sbi = EXT4_SB(sb); 826 827 if (!goal) 828 goal = sbi->s_inode_goal; 829 830 if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) { 831 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb); 832 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb); 833 ret2 = 0; 834 goto got_group; 835 } 836 837 if (sbi->s_log_groups_per_flex && test_opt(sb, OLDALLOC)) { 838 ret2 = find_group_flex(sb, dir, &group); 839 if (ret2 == -1) { 840 ret2 = find_group_other(sb, dir, &group, mode); 841 if (ret2 == 0 && once) { 842 once = 0; 843 printk(KERN_NOTICE "ext4: find_group_flex " 844 "failed, fallback succeeded dir %lu\n", 845 dir->i_ino); 846 } 847 } 848 goto got_group; 849 } 850 851 if (S_ISDIR(mode)) { 852 if (test_opt(sb, OLDALLOC)) 853 ret2 = find_group_dir(sb, dir, &group); 854 else 855 ret2 = find_group_orlov(sb, dir, &group, mode, qstr); 856 } else 857 ret2 = find_group_other(sb, dir, &group, mode); 858 859 got_group: 860 EXT4_I(dir)->i_last_alloc_group = group; 861 err = -ENOSPC; 862 if (ret2 == -1) 863 goto out; 864 865 for (i = 0; i < ngroups; i++, ino = 0) { 866 err = -EIO; 867 868 gdp = ext4_get_group_desc(sb, group, &group_desc_bh); 869 if (!gdp) 870 goto fail; 871 872 brelse(inode_bitmap_bh); 873 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group); 874 if (!inode_bitmap_bh) 875 goto fail; 876 877 repeat_in_this_group: 878 ino = ext4_find_next_zero_bit((unsigned long *) 879 inode_bitmap_bh->b_data, 880 EXT4_INODES_PER_GROUP(sb), ino); 881 882 if (ino < EXT4_INODES_PER_GROUP(sb)) { 883 884 BUFFER_TRACE(inode_bitmap_bh, "get_write_access"); 885 err = ext4_journal_get_write_access(handle, 886 inode_bitmap_bh); 887 if (err) 888 goto fail; 889 890 BUFFER_TRACE(group_desc_bh, "get_write_access"); 891 err = ext4_journal_get_write_access(handle, 892 group_desc_bh); 893 if (err) 894 goto fail; 895 if (!ext4_claim_inode(sb, inode_bitmap_bh, 896 ino, group, mode)) { 897 /* we won it */ 898 BUFFER_TRACE(inode_bitmap_bh, 899 "call ext4_handle_dirty_metadata"); 900 err = ext4_handle_dirty_metadata(handle, 901 NULL, 902 inode_bitmap_bh); 903 if (err) 904 goto fail; 905 /* zero bit is inode number 1*/ 906 ino++; 907 goto got; 908 } 909 /* we lost it */ 910 ext4_handle_release_buffer(handle, inode_bitmap_bh); 911 ext4_handle_release_buffer(handle, group_desc_bh); 912 913 if (++ino < EXT4_INODES_PER_GROUP(sb)) 914 goto repeat_in_this_group; 915 } 916 917 /* 918 * This case is possible in concurrent environment. It is very 919 * rare. We cannot repeat the find_group_xxx() call because 920 * that will simply return the same blockgroup, because the 921 * group descriptor metadata has not yet been updated. 922 * So we just go onto the next blockgroup. 923 */ 924 if (++group == ngroups) 925 group = 0; 926 } 927 err = -ENOSPC; 928 goto out; 929 930 got: 931 /* We may have to initialize the block bitmap if it isn't already */ 932 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) && 933 gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 934 struct buffer_head *block_bitmap_bh; 935 936 block_bitmap_bh = ext4_read_block_bitmap(sb, group); 937 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access"); 938 err = ext4_journal_get_write_access(handle, block_bitmap_bh); 939 if (err) { 940 brelse(block_bitmap_bh); 941 goto fail; 942 } 943 944 free = 0; 945 ext4_lock_group(sb, group); 946 /* recheck and clear flag under lock if we still need to */ 947 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 948 free = ext4_free_blocks_after_init(sb, group, gdp); 949 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT); 950 ext4_free_blks_set(sb, gdp, free); 951 gdp->bg_checksum = ext4_group_desc_csum(sbi, group, 952 gdp); 953 } 954 ext4_unlock_group(sb, group); 955 956 /* Don't need to dirty bitmap block if we didn't change it */ 957 if (free) { 958 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap"); 959 err = ext4_handle_dirty_metadata(handle, 960 NULL, block_bitmap_bh); 961 } 962 963 brelse(block_bitmap_bh); 964 if (err) 965 goto fail; 966 } 967 BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata"); 968 err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh); 969 if (err) 970 goto fail; 971 972 percpu_counter_dec(&sbi->s_freeinodes_counter); 973 if (S_ISDIR(mode)) 974 percpu_counter_inc(&sbi->s_dirs_counter); 975 sb->s_dirt = 1; 976 977 if (sbi->s_log_groups_per_flex) { 978 flex_group = ext4_flex_group(sbi, group); 979 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes); 980 } 981 982 inode->i_uid = current_fsuid(); 983 if (test_opt(sb, GRPID)) 984 inode->i_gid = dir->i_gid; 985 else if (dir->i_mode & S_ISGID) { 986 inode->i_gid = dir->i_gid; 987 if (S_ISDIR(mode)) 988 mode |= S_ISGID; 989 } else 990 inode->i_gid = current_fsgid(); 991 inode->i_mode = mode; 992 993 inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb); 994 /* This is the optimal IO size (for stat), not the fs block size */ 995 inode->i_blocks = 0; 996 inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime = 997 ext4_current_time(inode); 998 999 memset(ei->i_data, 0, sizeof(ei->i_data)); 1000 ei->i_dir_start_lookup = 0; 1001 ei->i_disksize = 0; 1002 1003 /* 1004 * Don't inherit extent flag from directory, amongst others. We set 1005 * extent flag on newly created directory and file only if -o extent 1006 * mount option is specified 1007 */ 1008 ei->i_flags = 1009 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED); 1010 ei->i_file_acl = 0; 1011 ei->i_dtime = 0; 1012 ei->i_block_group = group; 1013 ei->i_last_alloc_group = ~0; 1014 1015 ext4_set_inode_flags(inode); 1016 if (IS_DIRSYNC(inode)) 1017 ext4_handle_sync(handle); 1018 if (insert_inode_locked(inode) < 0) { 1019 err = -EINVAL; 1020 goto fail_drop; 1021 } 1022 spin_lock(&sbi->s_next_gen_lock); 1023 inode->i_generation = sbi->s_next_generation++; 1024 spin_unlock(&sbi->s_next_gen_lock); 1025 1026 ei->i_state_flags = 0; 1027 ext4_set_inode_state(inode, EXT4_STATE_NEW); 1028 1029 ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize; 1030 1031 ret = inode; 1032 dquot_initialize(inode); 1033 err = dquot_alloc_inode(inode); 1034 if (err) 1035 goto fail_drop; 1036 1037 err = ext4_init_acl(handle, inode, dir); 1038 if (err) 1039 goto fail_free_drop; 1040 1041 err = ext4_init_security(handle, inode, dir); 1042 if (err) 1043 goto fail_free_drop; 1044 1045 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) { 1046 /* set extent flag only for directory, file and normal symlink*/ 1047 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) { 1048 EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL; 1049 ext4_ext_tree_init(handle, inode); 1050 } 1051 } 1052 1053 err = ext4_mark_inode_dirty(handle, inode); 1054 if (err) { 1055 ext4_std_error(sb, err); 1056 goto fail_free_drop; 1057 } 1058 1059 ext4_debug("allocating inode %lu\n", inode->i_ino); 1060 trace_ext4_allocate_inode(inode, dir, mode); 1061 goto really_out; 1062 fail: 1063 ext4_std_error(sb, err); 1064 out: 1065 iput(inode); 1066 ret = ERR_PTR(err); 1067 really_out: 1068 brelse(inode_bitmap_bh); 1069 return ret; 1070 1071 fail_free_drop: 1072 dquot_free_inode(inode); 1073 1074 fail_drop: 1075 dquot_drop(inode); 1076 inode->i_flags |= S_NOQUOTA; 1077 inode->i_nlink = 0; 1078 unlock_new_inode(inode); 1079 iput(inode); 1080 brelse(inode_bitmap_bh); 1081 return ERR_PTR(err); 1082 } 1083 1084 /* Verify that we are loading a valid orphan from disk */ 1085 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino) 1086 { 1087 unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count); 1088 ext4_group_t block_group; 1089 int bit; 1090 struct buffer_head *bitmap_bh; 1091 struct inode *inode = NULL; 1092 long err = -EIO; 1093 1094 /* Error cases - e2fsck has already cleaned up for us */ 1095 if (ino > max_ino) { 1096 ext4_warning(sb, "bad orphan ino %lu! e2fsck was run?", ino); 1097 goto error; 1098 } 1099 1100 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb); 1101 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb); 1102 bitmap_bh = ext4_read_inode_bitmap(sb, block_group); 1103 if (!bitmap_bh) { 1104 ext4_warning(sb, "inode bitmap error for orphan %lu", ino); 1105 goto error; 1106 } 1107 1108 /* Having the inode bit set should be a 100% indicator that this 1109 * is a valid orphan (no e2fsck run on fs). Orphans also include 1110 * inodes that were being truncated, so we can't check i_nlink==0. 1111 */ 1112 if (!ext4_test_bit(bit, bitmap_bh->b_data)) 1113 goto bad_orphan; 1114 1115 inode = ext4_iget(sb, ino); 1116 if (IS_ERR(inode)) 1117 goto iget_failed; 1118 1119 /* 1120 * If the orphans has i_nlinks > 0 then it should be able to be 1121 * truncated, otherwise it won't be removed from the orphan list 1122 * during processing and an infinite loop will result. 1123 */ 1124 if (inode->i_nlink && !ext4_can_truncate(inode)) 1125 goto bad_orphan; 1126 1127 if (NEXT_ORPHAN(inode) > max_ino) 1128 goto bad_orphan; 1129 brelse(bitmap_bh); 1130 return inode; 1131 1132 iget_failed: 1133 err = PTR_ERR(inode); 1134 inode = NULL; 1135 bad_orphan: 1136 ext4_warning(sb, "bad orphan inode %lu! e2fsck was run?", ino); 1137 printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n", 1138 bit, (unsigned long long)bitmap_bh->b_blocknr, 1139 ext4_test_bit(bit, bitmap_bh->b_data)); 1140 printk(KERN_NOTICE "inode=%p\n", inode); 1141 if (inode) { 1142 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n", 1143 is_bad_inode(inode)); 1144 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n", 1145 NEXT_ORPHAN(inode)); 1146 printk(KERN_NOTICE "max_ino=%lu\n", max_ino); 1147 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink); 1148 /* Avoid freeing blocks if we got a bad deleted inode */ 1149 if (inode->i_nlink == 0) 1150 inode->i_blocks = 0; 1151 iput(inode); 1152 } 1153 brelse(bitmap_bh); 1154 error: 1155 return ERR_PTR(err); 1156 } 1157 1158 unsigned long ext4_count_free_inodes(struct super_block *sb) 1159 { 1160 unsigned long desc_count; 1161 struct ext4_group_desc *gdp; 1162 ext4_group_t i, ngroups = ext4_get_groups_count(sb); 1163 #ifdef EXT4FS_DEBUG 1164 struct ext4_super_block *es; 1165 unsigned long bitmap_count, x; 1166 struct buffer_head *bitmap_bh = NULL; 1167 1168 es = EXT4_SB(sb)->s_es; 1169 desc_count = 0; 1170 bitmap_count = 0; 1171 gdp = NULL; 1172 for (i = 0; i < ngroups; i++) { 1173 gdp = ext4_get_group_desc(sb, i, NULL); 1174 if (!gdp) 1175 continue; 1176 desc_count += ext4_free_inodes_count(sb, gdp); 1177 brelse(bitmap_bh); 1178 bitmap_bh = ext4_read_inode_bitmap(sb, i); 1179 if (!bitmap_bh) 1180 continue; 1181 1182 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8); 1183 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n", 1184 (unsigned long) i, ext4_free_inodes_count(sb, gdp), x); 1185 bitmap_count += x; 1186 } 1187 brelse(bitmap_bh); 1188 printk(KERN_DEBUG "ext4_count_free_inodes: " 1189 "stored = %u, computed = %lu, %lu\n", 1190 le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count); 1191 return desc_count; 1192 #else 1193 desc_count = 0; 1194 for (i = 0; i < ngroups; i++) { 1195 gdp = ext4_get_group_desc(sb, i, NULL); 1196 if (!gdp) 1197 continue; 1198 desc_count += ext4_free_inodes_count(sb, gdp); 1199 cond_resched(); 1200 } 1201 return desc_count; 1202 #endif 1203 } 1204 1205 /* Called at mount-time, super-block is locked */ 1206 unsigned long ext4_count_dirs(struct super_block * sb) 1207 { 1208 unsigned long count = 0; 1209 ext4_group_t i, ngroups = ext4_get_groups_count(sb); 1210 1211 for (i = 0; i < ngroups; i++) { 1212 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL); 1213 if (!gdp) 1214 continue; 1215 count += ext4_used_dirs_count(sb, gdp); 1216 } 1217 return count; 1218 } 1219