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 #include "ext4.h" 27 #include "ext4_jbd2.h" 28 #include "xattr.h" 29 #include "acl.h" 30 #include "group.h" 31 32 /* 33 * ialloc.c contains the inodes allocation and deallocation routines 34 */ 35 36 /* 37 * The free inodes are managed by bitmaps. A file system contains several 38 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 39 * block for inodes, N blocks for the inode table and data blocks. 40 * 41 * The file system contains group descriptors which are located after the 42 * super block. Each descriptor contains the number of the bitmap block and 43 * the free blocks count in the block. 44 */ 45 46 /* 47 * To avoid calling the atomic setbit hundreds or thousands of times, we only 48 * need to use it within a single byte (to ensure we get endianness right). 49 * We can use memset for the rest of the bitmap as there are no other users. 50 */ 51 void mark_bitmap_end(int start_bit, int end_bit, char *bitmap) 52 { 53 int i; 54 55 if (start_bit >= end_bit) 56 return; 57 58 ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit); 59 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++) 60 ext4_set_bit(i, bitmap); 61 if (i < end_bit) 62 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3); 63 } 64 65 /* Initializes an uninitialized inode bitmap */ 66 unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh, 67 ext4_group_t block_group, 68 struct ext4_group_desc *gdp) 69 { 70 struct ext4_sb_info *sbi = EXT4_SB(sb); 71 72 J_ASSERT_BH(bh, buffer_locked(bh)); 73 74 /* If checksum is bad mark all blocks and inodes use to prevent 75 * allocation, essentially implementing a per-group read-only flag. */ 76 if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) { 77 ext4_error(sb, __func__, "Checksum bad for group %u", 78 block_group); 79 ext4_free_blks_set(sb, gdp, 0); 80 ext4_free_inodes_set(sb, gdp, 0); 81 ext4_itable_unused_set(sb, gdp, 0); 82 memset(bh->b_data, 0xff, sb->s_blocksize); 83 return 0; 84 } 85 86 memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8); 87 mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8, 88 bh->b_data); 89 90 return EXT4_INODES_PER_GROUP(sb); 91 } 92 93 /* 94 * Read the inode allocation bitmap for a given block_group, reading 95 * into the specified slot in the superblock's bitmap cache. 96 * 97 * Return buffer_head of bitmap on success or NULL. 98 */ 99 static struct buffer_head * 100 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) 101 { 102 struct ext4_group_desc *desc; 103 struct buffer_head *bh = NULL; 104 ext4_fsblk_t bitmap_blk; 105 106 desc = ext4_get_group_desc(sb, block_group, NULL); 107 if (!desc) 108 return NULL; 109 bitmap_blk = ext4_inode_bitmap(sb, desc); 110 bh = sb_getblk(sb, bitmap_blk); 111 if (unlikely(!bh)) { 112 ext4_error(sb, __func__, 113 "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 spin_lock(sb_bgl_lock(EXT4_SB(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 spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group)); 132 unlock_buffer(bh); 133 return bh; 134 } 135 spin_unlock(sb_bgl_lock(EXT4_SB(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, __func__, 155 "Cannot read inode bitmap - " 156 "block_group = %u, inode_bitmap = %llu", 157 block_group, bitmap_blk); 158 return NULL; 159 } 160 return bh; 161 } 162 163 /* 164 * NOTE! When we get the inode, we're the only people 165 * that have access to it, and as such there are no 166 * race conditions we have to worry about. The inode 167 * is not on the hash-lists, and it cannot be reached 168 * through the filesystem because the directory entry 169 * has been deleted earlier. 170 * 171 * HOWEVER: we must make sure that we get no aliases, 172 * which means that we have to call "clear_inode()" 173 * _before_ we mark the inode not in use in the inode 174 * bitmaps. Otherwise a newly created file might use 175 * the same inode number (not actually the same pointer 176 * though), and then we'd have two inodes sharing the 177 * same inode number and space on the harddisk. 178 */ 179 void ext4_free_inode(handle_t *handle, struct inode *inode) 180 { 181 struct super_block *sb = inode->i_sb; 182 int is_directory; 183 unsigned long ino; 184 struct buffer_head *bitmap_bh = NULL; 185 struct buffer_head *bh2; 186 ext4_group_t block_group; 187 unsigned long bit; 188 struct ext4_group_desc *gdp; 189 struct ext4_super_block *es; 190 struct ext4_sb_info *sbi; 191 int fatal = 0, err, count, cleared; 192 193 if (atomic_read(&inode->i_count) > 1) { 194 printk(KERN_ERR "ext4_free_inode: inode has count=%d\n", 195 atomic_read(&inode->i_count)); 196 return; 197 } 198 if (inode->i_nlink) { 199 printk(KERN_ERR "ext4_free_inode: inode has nlink=%d\n", 200 inode->i_nlink); 201 return; 202 } 203 if (!sb) { 204 printk(KERN_ERR "ext4_free_inode: inode on " 205 "nonexistent device\n"); 206 return; 207 } 208 sbi = EXT4_SB(sb); 209 210 ino = inode->i_ino; 211 ext4_debug("freeing inode %lu\n", ino); 212 trace_mark(ext4_free_inode, 213 "dev %s ino %lu mode %d uid %lu gid %lu bocks %llu", 214 sb->s_id, inode->i_ino, inode->i_mode, 215 (unsigned long) inode->i_uid, (unsigned long) inode->i_gid, 216 (unsigned long long) inode->i_blocks); 217 218 /* 219 * Note: we must free any quota before locking the superblock, 220 * as writing the quota to disk may need the lock as well. 221 */ 222 vfs_dq_init(inode); 223 ext4_xattr_delete_inode(handle, inode); 224 vfs_dq_free_inode(inode); 225 vfs_dq_drop(inode); 226 227 is_directory = S_ISDIR(inode->i_mode); 228 229 /* Do this BEFORE marking the inode not in use or returning an error */ 230 clear_inode(inode); 231 232 es = EXT4_SB(sb)->s_es; 233 if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) { 234 ext4_error(sb, "ext4_free_inode", 235 "reserved or nonexistent inode %lu", ino); 236 goto error_return; 237 } 238 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb); 239 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb); 240 bitmap_bh = ext4_read_inode_bitmap(sb, block_group); 241 if (!bitmap_bh) 242 goto error_return; 243 244 BUFFER_TRACE(bitmap_bh, "get_write_access"); 245 fatal = ext4_journal_get_write_access(handle, bitmap_bh); 246 if (fatal) 247 goto error_return; 248 249 /* Ok, now we can actually update the inode bitmaps.. */ 250 spin_lock(sb_bgl_lock(sbi, block_group)); 251 cleared = ext4_clear_bit(bit, bitmap_bh->b_data); 252 spin_unlock(sb_bgl_lock(sbi, block_group)); 253 if (!cleared) 254 ext4_error(sb, "ext4_free_inode", 255 "bit already cleared for inode %lu", ino); 256 else { 257 gdp = ext4_get_group_desc(sb, block_group, &bh2); 258 259 BUFFER_TRACE(bh2, "get_write_access"); 260 fatal = ext4_journal_get_write_access(handle, bh2); 261 if (fatal) goto error_return; 262 263 if (gdp) { 264 spin_lock(sb_bgl_lock(sbi, block_group)); 265 count = ext4_free_inodes_count(sb, gdp) + 1; 266 ext4_free_inodes_set(sb, gdp, count); 267 if (is_directory) { 268 count = ext4_used_dirs_count(sb, gdp) - 1; 269 ext4_used_dirs_set(sb, gdp, count); 270 if (sbi->s_log_groups_per_flex) { 271 ext4_group_t f; 272 273 f = ext4_flex_group(sbi, block_group); 274 atomic_dec(&sbi->s_flex_groups[f].free_inodes); 275 } 276 277 } 278 gdp->bg_checksum = ext4_group_desc_csum(sbi, 279 block_group, gdp); 280 spin_unlock(sb_bgl_lock(sbi, block_group)); 281 percpu_counter_inc(&sbi->s_freeinodes_counter); 282 if (is_directory) 283 percpu_counter_dec(&sbi->s_dirs_counter); 284 285 if (sbi->s_log_groups_per_flex) { 286 ext4_group_t f; 287 288 f = ext4_flex_group(sbi, block_group); 289 atomic_inc(&sbi->s_flex_groups[f].free_inodes); 290 } 291 } 292 BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata"); 293 err = ext4_handle_dirty_metadata(handle, NULL, bh2); 294 if (!fatal) fatal = err; 295 } 296 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata"); 297 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh); 298 if (!fatal) 299 fatal = err; 300 sb->s_dirt = 1; 301 error_return: 302 brelse(bitmap_bh); 303 ext4_std_error(sb, fatal); 304 } 305 306 /* 307 * There are two policies for allocating an inode. If the new inode is 308 * a directory, then a forward search is made for a block group with both 309 * free space and a low directory-to-inode ratio; if that fails, then of 310 * the groups with above-average free space, that group with the fewest 311 * directories already is chosen. 312 * 313 * For other inodes, search forward from the parent directory\'s block 314 * group to find a free inode. 315 */ 316 static int find_group_dir(struct super_block *sb, struct inode *parent, 317 ext4_group_t *best_group) 318 { 319 ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count; 320 unsigned int freei, avefreei; 321 struct ext4_group_desc *desc, *best_desc = NULL; 322 ext4_group_t group; 323 int ret = -1; 324 325 freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter); 326 avefreei = freei / ngroups; 327 328 for (group = 0; group < ngroups; group++) { 329 desc = ext4_get_group_desc(sb, group, NULL); 330 if (!desc || !ext4_free_inodes_count(sb, desc)) 331 continue; 332 if (ext4_free_inodes_count(sb, desc) < avefreei) 333 continue; 334 if (!best_desc || 335 (ext4_free_blks_count(sb, desc) > 336 ext4_free_blks_count(sb, best_desc))) { 337 *best_group = group; 338 best_desc = desc; 339 ret = 0; 340 } 341 } 342 return ret; 343 } 344 345 #define free_block_ratio 10 346 347 static int find_group_flex(struct super_block *sb, struct inode *parent, 348 ext4_group_t *best_group) 349 { 350 struct ext4_sb_info *sbi = EXT4_SB(sb); 351 struct ext4_group_desc *desc; 352 struct buffer_head *bh; 353 struct flex_groups *flex_group = sbi->s_flex_groups; 354 ext4_group_t parent_group = EXT4_I(parent)->i_block_group; 355 ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group); 356 ext4_group_t ngroups = sbi->s_groups_count; 357 int flex_size = ext4_flex_bg_size(sbi); 358 ext4_group_t best_flex = parent_fbg_group; 359 int blocks_per_flex = sbi->s_blocks_per_group * flex_size; 360 int flexbg_free_blocks; 361 int flex_freeb_ratio; 362 ext4_group_t n_fbg_groups; 363 ext4_group_t i; 364 365 n_fbg_groups = (sbi->s_groups_count + flex_size - 1) >> 366 sbi->s_log_groups_per_flex; 367 368 find_close_to_parent: 369 flexbg_free_blocks = atomic_read(&flex_group[best_flex].free_blocks); 370 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex; 371 if (atomic_read(&flex_group[best_flex].free_inodes) && 372 flex_freeb_ratio > free_block_ratio) 373 goto found_flexbg; 374 375 if (best_flex && best_flex == parent_fbg_group) { 376 best_flex--; 377 goto find_close_to_parent; 378 } 379 380 for (i = 0; i < n_fbg_groups; i++) { 381 if (i == parent_fbg_group || i == parent_fbg_group - 1) 382 continue; 383 384 flexbg_free_blocks = atomic_read(&flex_group[i].free_blocks); 385 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex; 386 387 if (flex_freeb_ratio > free_block_ratio && 388 (atomic_read(&flex_group[i].free_inodes))) { 389 best_flex = i; 390 goto found_flexbg; 391 } 392 393 if ((atomic_read(&flex_group[best_flex].free_inodes) == 0) || 394 ((atomic_read(&flex_group[i].free_blocks) > 395 atomic_read(&flex_group[best_flex].free_blocks)) && 396 atomic_read(&flex_group[i].free_inodes))) 397 best_flex = i; 398 } 399 400 if (!atomic_read(&flex_group[best_flex].free_inodes) || 401 !atomic_read(&flex_group[best_flex].free_blocks)) 402 return -1; 403 404 found_flexbg: 405 for (i = best_flex * flex_size; i < ngroups && 406 i < (best_flex + 1) * flex_size; i++) { 407 desc = ext4_get_group_desc(sb, i, &bh); 408 if (ext4_free_inodes_count(sb, desc)) { 409 *best_group = i; 410 goto out; 411 } 412 } 413 414 return -1; 415 out: 416 return 0; 417 } 418 419 struct orlov_stats { 420 __u32 free_inodes; 421 __u32 free_blocks; 422 __u32 used_dirs; 423 }; 424 425 /* 426 * Helper function for Orlov's allocator; returns critical information 427 * for a particular block group or flex_bg. If flex_size is 1, then g 428 * is a block group number; otherwise it is flex_bg number. 429 */ 430 void get_orlov_stats(struct super_block *sb, ext4_group_t g, 431 int flex_size, struct orlov_stats *stats) 432 { 433 struct ext4_group_desc *desc; 434 struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups; 435 436 if (flex_size > 1) { 437 stats->free_inodes = atomic_read(&flex_group[g].free_inodes); 438 stats->free_blocks = atomic_read(&flex_group[g].free_blocks); 439 stats->used_dirs = atomic_read(&flex_group[g].used_dirs); 440 return; 441 } 442 443 desc = ext4_get_group_desc(sb, g, NULL); 444 if (desc) { 445 stats->free_inodes = ext4_free_inodes_count(sb, desc); 446 stats->free_blocks = ext4_free_blks_count(sb, desc); 447 stats->used_dirs = ext4_used_dirs_count(sb, desc); 448 } else { 449 stats->free_inodes = 0; 450 stats->free_blocks = 0; 451 stats->used_dirs = 0; 452 } 453 } 454 455 /* 456 * Orlov's allocator for directories. 457 * 458 * We always try to spread first-level directories. 459 * 460 * If there are blockgroups with both free inodes and free blocks counts 461 * not worse than average we return one with smallest directory count. 462 * Otherwise we simply return a random group. 463 * 464 * For the rest rules look so: 465 * 466 * It's OK to put directory into a group unless 467 * it has too many directories already (max_dirs) or 468 * it has too few free inodes left (min_inodes) or 469 * it has too few free blocks left (min_blocks) or 470 * Parent's group is preferred, if it doesn't satisfy these 471 * conditions we search cyclically through the rest. If none 472 * of the groups look good we just look for a group with more 473 * free inodes than average (starting at parent's group). 474 */ 475 476 static int find_group_orlov(struct super_block *sb, struct inode *parent, 477 ext4_group_t *group, int mode) 478 { 479 ext4_group_t parent_group = EXT4_I(parent)->i_block_group; 480 struct ext4_sb_info *sbi = EXT4_SB(sb); 481 ext4_group_t ngroups = sbi->s_groups_count; 482 int inodes_per_group = EXT4_INODES_PER_GROUP(sb); 483 unsigned int freei, avefreei; 484 ext4_fsblk_t freeb, avefreeb; 485 unsigned int ndirs; 486 int max_dirs, min_inodes; 487 ext4_grpblk_t min_blocks; 488 ext4_group_t i, grp, g; 489 struct ext4_group_desc *desc; 490 struct orlov_stats stats; 491 int flex_size = ext4_flex_bg_size(sbi); 492 493 if (flex_size > 1) { 494 ngroups = (ngroups + flex_size - 1) >> 495 sbi->s_log_groups_per_flex; 496 parent_group >>= sbi->s_log_groups_per_flex; 497 } 498 499 freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter); 500 avefreei = freei / ngroups; 501 freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter); 502 avefreeb = freeb; 503 do_div(avefreeb, ngroups); 504 ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter); 505 506 if (S_ISDIR(mode) && 507 ((parent == sb->s_root->d_inode) || 508 (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL))) { 509 int best_ndir = inodes_per_group; 510 int ret = -1; 511 512 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 >= sbi->s_groups_count) 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 = sbi->s_groups_count; 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 ngroups = EXT4_SB(sb)->s_groups_count; 617 struct ext4_group_desc *desc; 618 ext4_group_t i, last; 619 int flex_size = ext4_flex_bg_size(EXT4_SB(sb)); 620 621 /* 622 * Try to place the inode is the same flex group as its 623 * parent. If we can't find space, use the Orlov algorithm to 624 * find another flex group, and store that information in the 625 * parent directory's inode information so that use that flex 626 * group for future allocations. 627 */ 628 if (flex_size > 1) { 629 int retry = 0; 630 631 try_again: 632 parent_group &= ~(flex_size-1); 633 last = parent_group + flex_size; 634 if (last > ngroups) 635 last = ngroups; 636 for (i = parent_group; i < last; i++) { 637 desc = ext4_get_group_desc(sb, i, NULL); 638 if (desc && ext4_free_inodes_count(sb, desc)) { 639 *group = i; 640 return 0; 641 } 642 } 643 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) { 644 retry = 1; 645 parent_group = EXT4_I(parent)->i_last_alloc_group; 646 goto try_again; 647 } 648 /* 649 * If this didn't work, use the Orlov search algorithm 650 * to find a new flex group; we pass in the mode to 651 * avoid the topdir algorithms. 652 */ 653 *group = parent_group + flex_size; 654 if (*group > ngroups) 655 *group = 0; 656 return find_group_orlov(sb, parent, group, mode); 657 } 658 659 /* 660 * Try to place the inode in its parent directory 661 */ 662 *group = parent_group; 663 desc = ext4_get_group_desc(sb, *group, NULL); 664 if (desc && ext4_free_inodes_count(sb, desc) && 665 ext4_free_blks_count(sb, desc)) 666 return 0; 667 668 /* 669 * We're going to place this inode in a different blockgroup from its 670 * parent. We want to cause files in a common directory to all land in 671 * the same blockgroup. But we want files which are in a different 672 * directory which shares a blockgroup with our parent to land in a 673 * different blockgroup. 674 * 675 * So add our directory's i_ino into the starting point for the hash. 676 */ 677 *group = (*group + parent->i_ino) % ngroups; 678 679 /* 680 * Use a quadratic hash to find a group with a free inode and some free 681 * blocks. 682 */ 683 for (i = 1; i < ngroups; i <<= 1) { 684 *group += i; 685 if (*group >= ngroups) 686 *group -= ngroups; 687 desc = ext4_get_group_desc(sb, *group, NULL); 688 if (desc && ext4_free_inodes_count(sb, desc) && 689 ext4_free_blks_count(sb, desc)) 690 return 0; 691 } 692 693 /* 694 * That failed: try linear search for a free inode, even if that group 695 * has no free blocks. 696 */ 697 *group = parent_group; 698 for (i = 0; i < ngroups; i++) { 699 if (++*group >= ngroups) 700 *group = 0; 701 desc = ext4_get_group_desc(sb, *group, NULL); 702 if (desc && ext4_free_inodes_count(sb, desc)) 703 return 0; 704 } 705 706 return -1; 707 } 708 709 /* 710 * claim the inode from the inode bitmap. If the group 711 * is uninit we need to take the groups's sb_bgl_lock 712 * and clear the uninit flag. The inode bitmap update 713 * and group desc uninit flag clear should be done 714 * after holding sb_bgl_lock so that ext4_read_inode_bitmap 715 * doesn't race with the ext4_claim_inode 716 */ 717 static int ext4_claim_inode(struct super_block *sb, 718 struct buffer_head *inode_bitmap_bh, 719 unsigned long ino, ext4_group_t group, int mode) 720 { 721 int free = 0, retval = 0, count; 722 struct ext4_sb_info *sbi = EXT4_SB(sb); 723 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL); 724 725 spin_lock(sb_bgl_lock(sbi, group)); 726 if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) { 727 /* not a free inode */ 728 retval = 1; 729 goto err_ret; 730 } 731 ino++; 732 if ((group == 0 && ino < EXT4_FIRST_INO(sb)) || 733 ino > EXT4_INODES_PER_GROUP(sb)) { 734 spin_unlock(sb_bgl_lock(sbi, group)); 735 ext4_error(sb, __func__, 736 "reserved inode or inode > inodes count - " 737 "block_group = %u, inode=%lu", group, 738 ino + group * EXT4_INODES_PER_GROUP(sb)); 739 return 1; 740 } 741 /* If we didn't allocate from within the initialized part of the inode 742 * table then we need to initialize up to this inode. */ 743 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { 744 745 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) { 746 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT); 747 /* When marking the block group with 748 * ~EXT4_BG_INODE_UNINIT we don't want to depend 749 * on the value of bg_itable_unused even though 750 * mke2fs could have initialized the same for us. 751 * Instead we calculated the value below 752 */ 753 754 free = 0; 755 } else { 756 free = EXT4_INODES_PER_GROUP(sb) - 757 ext4_itable_unused_count(sb, gdp); 758 } 759 760 /* 761 * Check the relative inode number against the last used 762 * relative inode number in this group. if it is greater 763 * we need to update the bg_itable_unused count 764 * 765 */ 766 if (ino > free) 767 ext4_itable_unused_set(sb, gdp, 768 (EXT4_INODES_PER_GROUP(sb) - ino)); 769 } 770 count = ext4_free_inodes_count(sb, gdp) - 1; 771 ext4_free_inodes_set(sb, gdp, count); 772 if (S_ISDIR(mode)) { 773 count = ext4_used_dirs_count(sb, gdp) + 1; 774 ext4_used_dirs_set(sb, gdp, count); 775 if (sbi->s_log_groups_per_flex) { 776 ext4_group_t f = ext4_flex_group(sbi, group); 777 778 atomic_inc(&sbi->s_flex_groups[f].free_inodes); 779 } 780 } 781 gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp); 782 err_ret: 783 spin_unlock(sb_bgl_lock(sbi, group)); 784 return retval; 785 } 786 787 /* 788 * There are two policies for allocating an inode. If the new inode is 789 * a directory, then a forward search is made for a block group with both 790 * free space and a low directory-to-inode ratio; if that fails, then of 791 * the groups with above-average free space, that group with the fewest 792 * directories already is chosen. 793 * 794 * For other inodes, search forward from the parent directory's block 795 * group to find a free inode. 796 */ 797 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode) 798 { 799 struct super_block *sb; 800 struct buffer_head *inode_bitmap_bh = NULL; 801 struct buffer_head *group_desc_bh; 802 ext4_group_t group = 0; 803 unsigned long ino = 0; 804 struct inode *inode; 805 struct ext4_group_desc *gdp = NULL; 806 struct ext4_super_block *es; 807 struct ext4_inode_info *ei; 808 struct ext4_sb_info *sbi; 809 int ret2, err = 0; 810 struct inode *ret; 811 ext4_group_t i; 812 int free = 0; 813 static int once = 1; 814 ext4_group_t flex_group; 815 816 /* Cannot create files in a deleted directory */ 817 if (!dir || !dir->i_nlink) 818 return ERR_PTR(-EPERM); 819 820 sb = dir->i_sb; 821 trace_mark(ext4_request_inode, "dev %s dir %lu mode %d", sb->s_id, 822 dir->i_ino, mode); 823 inode = new_inode(sb); 824 if (!inode) 825 return ERR_PTR(-ENOMEM); 826 ei = EXT4_I(inode); 827 828 sbi = EXT4_SB(sb); 829 es = sbi->s_es; 830 831 if (sbi->s_log_groups_per_flex && test_opt(sb, OLDALLOC)) { 832 ret2 = find_group_flex(sb, dir, &group); 833 if (ret2 == -1) { 834 ret2 = find_group_other(sb, dir, &group, mode); 835 if (ret2 == 0 && once) { 836 once = 0; 837 printk(KERN_NOTICE "ext4: find_group_flex " 838 "failed, fallback succeeded dir %lu\n", 839 dir->i_ino); 840 } 841 } 842 goto got_group; 843 } 844 845 if (S_ISDIR(mode)) { 846 if (test_opt(sb, OLDALLOC)) 847 ret2 = find_group_dir(sb, dir, &group); 848 else 849 ret2 = find_group_orlov(sb, dir, &group, mode); 850 } else 851 ret2 = find_group_other(sb, dir, &group, mode); 852 853 got_group: 854 EXT4_I(dir)->i_last_alloc_group = group; 855 err = -ENOSPC; 856 if (ret2 == -1) 857 goto out; 858 859 for (i = 0; i < sbi->s_groups_count; i++) { 860 err = -EIO; 861 862 gdp = ext4_get_group_desc(sb, group, &group_desc_bh); 863 if (!gdp) 864 goto fail; 865 866 brelse(inode_bitmap_bh); 867 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group); 868 if (!inode_bitmap_bh) 869 goto fail; 870 871 ino = 0; 872 873 repeat_in_this_group: 874 ino = ext4_find_next_zero_bit((unsigned long *) 875 inode_bitmap_bh->b_data, 876 EXT4_INODES_PER_GROUP(sb), ino); 877 878 if (ino < EXT4_INODES_PER_GROUP(sb)) { 879 880 BUFFER_TRACE(inode_bitmap_bh, "get_write_access"); 881 err = ext4_journal_get_write_access(handle, 882 inode_bitmap_bh); 883 if (err) 884 goto fail; 885 886 BUFFER_TRACE(group_desc_bh, "get_write_access"); 887 err = ext4_journal_get_write_access(handle, 888 group_desc_bh); 889 if (err) 890 goto fail; 891 if (!ext4_claim_inode(sb, inode_bitmap_bh, 892 ino, group, mode)) { 893 /* we won it */ 894 BUFFER_TRACE(inode_bitmap_bh, 895 "call ext4_handle_dirty_metadata"); 896 err = ext4_handle_dirty_metadata(handle, 897 inode, 898 inode_bitmap_bh); 899 if (err) 900 goto fail; 901 /* zero bit is inode number 1*/ 902 ino++; 903 goto got; 904 } 905 /* we lost it */ 906 ext4_handle_release_buffer(handle, inode_bitmap_bh); 907 ext4_handle_release_buffer(handle, group_desc_bh); 908 909 if (++ino < EXT4_INODES_PER_GROUP(sb)) 910 goto repeat_in_this_group; 911 } 912 913 /* 914 * This case is possible in concurrent environment. It is very 915 * rare. We cannot repeat the find_group_xxx() call because 916 * that will simply return the same blockgroup, because the 917 * group descriptor metadata has not yet been updated. 918 * So we just go onto the next blockgroup. 919 */ 920 if (++group == sbi->s_groups_count) 921 group = 0; 922 } 923 err = -ENOSPC; 924 goto out; 925 926 got: 927 /* We may have to initialize the block bitmap if it isn't already */ 928 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) && 929 gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 930 struct buffer_head *block_bitmap_bh; 931 932 block_bitmap_bh = ext4_read_block_bitmap(sb, group); 933 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access"); 934 err = ext4_journal_get_write_access(handle, block_bitmap_bh); 935 if (err) { 936 brelse(block_bitmap_bh); 937 goto fail; 938 } 939 940 free = 0; 941 spin_lock(sb_bgl_lock(sbi, group)); 942 /* recheck and clear flag under lock if we still need to */ 943 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { 944 free = ext4_free_blocks_after_init(sb, group, gdp); 945 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT); 946 ext4_free_blks_set(sb, gdp, free); 947 gdp->bg_checksum = ext4_group_desc_csum(sbi, group, 948 gdp); 949 } 950 spin_unlock(sb_bgl_lock(sbi, group)); 951 952 /* Don't need to dirty bitmap block if we didn't change it */ 953 if (free) { 954 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap"); 955 err = ext4_handle_dirty_metadata(handle, 956 NULL, block_bitmap_bh); 957 } 958 959 brelse(block_bitmap_bh); 960 if (err) 961 goto fail; 962 } 963 BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata"); 964 err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh); 965 if (err) 966 goto fail; 967 968 percpu_counter_dec(&sbi->s_freeinodes_counter); 969 if (S_ISDIR(mode)) 970 percpu_counter_inc(&sbi->s_dirs_counter); 971 sb->s_dirt = 1; 972 973 if (sbi->s_log_groups_per_flex) { 974 flex_group = ext4_flex_group(sbi, group); 975 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes); 976 } 977 978 inode->i_uid = current_fsuid(); 979 if (test_opt(sb, GRPID)) 980 inode->i_gid = dir->i_gid; 981 else if (dir->i_mode & S_ISGID) { 982 inode->i_gid = dir->i_gid; 983 if (S_ISDIR(mode)) 984 mode |= S_ISGID; 985 } else 986 inode->i_gid = current_fsgid(); 987 inode->i_mode = mode; 988 989 inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb); 990 /* This is the optimal IO size (for stat), not the fs block size */ 991 inode->i_blocks = 0; 992 inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime = 993 ext4_current_time(inode); 994 995 memset(ei->i_data, 0, sizeof(ei->i_data)); 996 ei->i_dir_start_lookup = 0; 997 ei->i_disksize = 0; 998 999 /* 1000 * Don't inherit extent flag from directory, amongst others. We set 1001 * extent flag on newly created directory and file only if -o extent 1002 * mount option is specified 1003 */ 1004 ei->i_flags = 1005 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED); 1006 ei->i_file_acl = 0; 1007 ei->i_dtime = 0; 1008 ei->i_block_group = group; 1009 ei->i_last_alloc_group = ~0; 1010 1011 ext4_set_inode_flags(inode); 1012 if (IS_DIRSYNC(inode)) 1013 ext4_handle_sync(handle); 1014 if (insert_inode_locked(inode) < 0) { 1015 err = -EINVAL; 1016 goto fail_drop; 1017 } 1018 spin_lock(&sbi->s_next_gen_lock); 1019 inode->i_generation = sbi->s_next_generation++; 1020 spin_unlock(&sbi->s_next_gen_lock); 1021 1022 ei->i_state = EXT4_STATE_NEW; 1023 1024 ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize; 1025 1026 ret = inode; 1027 if (vfs_dq_alloc_inode(inode)) { 1028 err = -EDQUOT; 1029 goto fail_drop; 1030 } 1031 1032 err = ext4_init_acl(handle, inode, dir); 1033 if (err) 1034 goto fail_free_drop; 1035 1036 err = ext4_init_security(handle, inode, dir); 1037 if (err) 1038 goto fail_free_drop; 1039 1040 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) { 1041 /* set extent flag only for directory, file and normal symlink*/ 1042 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) { 1043 EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL; 1044 ext4_ext_tree_init(handle, inode); 1045 } 1046 } 1047 1048 err = ext4_mark_inode_dirty(handle, inode); 1049 if (err) { 1050 ext4_std_error(sb, err); 1051 goto fail_free_drop; 1052 } 1053 1054 ext4_debug("allocating inode %lu\n", inode->i_ino); 1055 trace_mark(ext4_allocate_inode, "dev %s ino %lu dir %lu mode %d", 1056 sb->s_id, inode->i_ino, dir->i_ino, mode); 1057 goto really_out; 1058 fail: 1059 ext4_std_error(sb, err); 1060 out: 1061 iput(inode); 1062 ret = ERR_PTR(err); 1063 really_out: 1064 brelse(inode_bitmap_bh); 1065 return ret; 1066 1067 fail_free_drop: 1068 vfs_dq_free_inode(inode); 1069 1070 fail_drop: 1071 vfs_dq_drop(inode); 1072 inode->i_flags |= S_NOQUOTA; 1073 inode->i_nlink = 0; 1074 unlock_new_inode(inode); 1075 iput(inode); 1076 brelse(inode_bitmap_bh); 1077 return ERR_PTR(err); 1078 } 1079 1080 /* Verify that we are loading a valid orphan from disk */ 1081 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino) 1082 { 1083 unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count); 1084 ext4_group_t block_group; 1085 int bit; 1086 struct buffer_head *bitmap_bh; 1087 struct inode *inode = NULL; 1088 long err = -EIO; 1089 1090 /* Error cases - e2fsck has already cleaned up for us */ 1091 if (ino > max_ino) { 1092 ext4_warning(sb, __func__, 1093 "bad orphan ino %lu! e2fsck was run?", ino); 1094 goto error; 1095 } 1096 1097 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb); 1098 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb); 1099 bitmap_bh = ext4_read_inode_bitmap(sb, block_group); 1100 if (!bitmap_bh) { 1101 ext4_warning(sb, __func__, 1102 "inode bitmap error for orphan %lu", ino); 1103 goto error; 1104 } 1105 1106 /* Having the inode bit set should be a 100% indicator that this 1107 * is a valid orphan (no e2fsck run on fs). Orphans also include 1108 * inodes that were being truncated, so we can't check i_nlink==0. 1109 */ 1110 if (!ext4_test_bit(bit, bitmap_bh->b_data)) 1111 goto bad_orphan; 1112 1113 inode = ext4_iget(sb, ino); 1114 if (IS_ERR(inode)) 1115 goto iget_failed; 1116 1117 /* 1118 * If the orphans has i_nlinks > 0 then it should be able to be 1119 * truncated, otherwise it won't be removed from the orphan list 1120 * during processing and an infinite loop will result. 1121 */ 1122 if (inode->i_nlink && !ext4_can_truncate(inode)) 1123 goto bad_orphan; 1124 1125 if (NEXT_ORPHAN(inode) > max_ino) 1126 goto bad_orphan; 1127 brelse(bitmap_bh); 1128 return inode; 1129 1130 iget_failed: 1131 err = PTR_ERR(inode); 1132 inode = NULL; 1133 bad_orphan: 1134 ext4_warning(sb, __func__, 1135 "bad orphan inode %lu! e2fsck was run?", ino); 1136 printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n", 1137 bit, (unsigned long long)bitmap_bh->b_blocknr, 1138 ext4_test_bit(bit, bitmap_bh->b_data)); 1139 printk(KERN_NOTICE "inode=%p\n", inode); 1140 if (inode) { 1141 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n", 1142 is_bad_inode(inode)); 1143 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n", 1144 NEXT_ORPHAN(inode)); 1145 printk(KERN_NOTICE "max_ino=%lu\n", max_ino); 1146 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink); 1147 /* Avoid freeing blocks if we got a bad deleted inode */ 1148 if (inode->i_nlink == 0) 1149 inode->i_blocks = 0; 1150 iput(inode); 1151 } 1152 brelse(bitmap_bh); 1153 error: 1154 return ERR_PTR(err); 1155 } 1156 1157 unsigned long ext4_count_free_inodes(struct super_block *sb) 1158 { 1159 unsigned long desc_count; 1160 struct ext4_group_desc *gdp; 1161 ext4_group_t i; 1162 #ifdef EXT4FS_DEBUG 1163 struct ext4_super_block *es; 1164 unsigned long bitmap_count, x; 1165 struct buffer_head *bitmap_bh = NULL; 1166 1167 es = EXT4_SB(sb)->s_es; 1168 desc_count = 0; 1169 bitmap_count = 0; 1170 gdp = NULL; 1171 for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) { 1172 gdp = ext4_get_group_desc(sb, i, NULL); 1173 if (!gdp) 1174 continue; 1175 desc_count += ext4_free_inodes_count(sb, gdp); 1176 brelse(bitmap_bh); 1177 bitmap_bh = ext4_read_inode_bitmap(sb, i); 1178 if (!bitmap_bh) 1179 continue; 1180 1181 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8); 1182 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n", 1183 i, ext4_free_inodes_count(sb, gdp), x); 1184 bitmap_count += x; 1185 } 1186 brelse(bitmap_bh); 1187 printk(KERN_DEBUG "ext4_count_free_inodes: " 1188 "stored = %u, computed = %lu, %lu\n", 1189 le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count); 1190 return desc_count; 1191 #else 1192 desc_count = 0; 1193 for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) { 1194 gdp = ext4_get_group_desc(sb, i, NULL); 1195 if (!gdp) 1196 continue; 1197 desc_count += ext4_free_inodes_count(sb, gdp); 1198 cond_resched(); 1199 } 1200 return desc_count; 1201 #endif 1202 } 1203 1204 /* Called at mount-time, super-block is locked */ 1205 unsigned long ext4_count_dirs(struct super_block * sb) 1206 { 1207 unsigned long count = 0; 1208 ext4_group_t i; 1209 1210 for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) { 1211 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL); 1212 if (!gdp) 1213 continue; 1214 count += ext4_used_dirs_count(sb, gdp); 1215 } 1216 return count; 1217 } 1218