fs/ext4/ialloc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/ialloc.c
   4  *
   5  * Copyright (C) 1992, 1993, 1994, 1995
   6  * Remy Card ([email protected])
   7  * Laboratoire MASI - Institut Blaise Pascal
   8  * Universite Pierre et Marie Curie (Paris VI)
   9  *
  10  *  BSD ufs-inspired inode and directory allocation by
  11  *  Stephen Tweedie ([email protected]), 1993
  12  *  Big-endian to little-endian byte-swapping/bitmaps by
  13  *        David S. Miller ([email protected]), 1995
  14  */
  15
  16 #include <linux/time.h>
  17 #include <linux/fs.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 <linux/cred.h>
  26
  27 #include <asm/byteorder.h>
  28
  29 #include "ext4.h"
  30 #include "ext4_jbd2.h"
  31 #include "xattr.h"
  32 #include "acl.h"
  33
  34 #include <trace/events/ext4.h>
  35
  36 /*
  37  * ialloc.c contains the inodes allocation and deallocation routines
  38  */
  39
  40 /*
  41  * The free inodes are managed by bitmaps.  A file system contains several
  42  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  43  * block for inodes, N blocks for the inode table and data blocks.
  44  *
  45  * The file system contains group descriptors which are located after the
  46  * super block.  Each descriptor contains the number of the bitmap block and
  47  * the free blocks count in the block.
  48  */
  49
  50 /*
  51  * To avoid calling the atomic setbit hundreds or thousands of times, we only
  52  * need to use it within a single byte (to ensure we get endianness right).
  53  * We can use memset for the rest of the bitmap as there are no other users.
  54  */
  55 void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
  56 {
  57         int i;
  58
  59         if (start_bit >= end_bit)
  60                 return;
  61
  62         ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
  63         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
  64                 ext4_set_bit(i, bitmap);
  65         if (i < end_bit)
  66                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
  67 }
  68
  69 void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
  70 {
  71         if (uptodate) {
  72                 set_buffer_uptodate(bh);
  73                 set_bitmap_uptodate(bh);
  74         }
  75         unlock_buffer(bh);
  76         put_bh(bh);
  77 }
  78
  79 static int ext4_validate_inode_bitmap(struct super_block *sb,
  80                                       struct ext4_group_desc *desc,
  81                                       ext4_group_t block_group,
  82                                       struct buffer_head *bh)
  83 {
  84         ext4_fsblk_t    blk;
  85         struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
  86
  87         if (buffer_verified(bh))
  88                 return 0;
  89         if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
  90                 return -EFSCORRUPTED;
  91
  92         ext4_lock_group(sb, block_group);
  93         blk = ext4_inode_bitmap(sb, desc);
  94         if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
  95                                            EXT4_INODES_PER_GROUP(sb) / 8)) {
  96                 ext4_unlock_group(sb, block_group);
  97                 ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
  98                            "inode_bitmap = %llu", block_group, blk);
  99                 ext4_mark_group_bitmap_corrupted(sb, block_group,
 100                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 101                 return -EFSBADCRC;
 102         }
 103         set_buffer_verified(bh);
 104         ext4_unlock_group(sb, block_group);
 105         return 0;
 106 }
 107
 108 /*
 109  * Read the inode allocation bitmap for a given block_group, reading
 110  * into the specified slot in the superblock's bitmap cache.
 111  *
 112  * Return buffer_head of bitmap on success or NULL.
 113  */
 114 static struct buffer_head *
 115 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 116 {
 117         struct ext4_group_desc *desc;
 118         struct ext4_sb_info *sbi = EXT4_SB(sb);
 119         struct buffer_head *bh = NULL;
 120         ext4_fsblk_t bitmap_blk;
 121         int err;
 122
 123         desc = ext4_get_group_desc(sb, block_group, NULL);
 124         if (!desc)
 125                 return ERR_PTR(-EFSCORRUPTED);
 126
 127         bitmap_blk = ext4_inode_bitmap(sb, desc);
 128         if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
 129             (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
 130                 ext4_error(sb, "Invalid inode bitmap blk %llu in "
 131                            "block_group %u", bitmap_blk, block_group);
 132                 ext4_mark_group_bitmap_corrupted(sb, block_group,
 133                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 134                 return ERR_PTR(-EFSCORRUPTED);
 135         }
 136         bh = sb_getblk(sb, bitmap_blk);
 137         if (unlikely(!bh)) {
 138                 ext4_error(sb, "Cannot read inode bitmap - "
 139                             "block_group = %u, inode_bitmap = %llu",
 140                             block_group, bitmap_blk);
 141                 return ERR_PTR(-ENOMEM);
 142         }
 143         if (bitmap_uptodate(bh))
 144                 goto verify;
 145
 146         lock_buffer(bh);
 147         if (bitmap_uptodate(bh)) {
 148                 unlock_buffer(bh);
 149                 goto verify;
 150         }
 151
 152         ext4_lock_group(sb, block_group);
 153         if (ext4_has_group_desc_csum(sb) &&
 154             (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
 155                 if (block_group == 0) {
 156                         ext4_unlock_group(sb, block_group);
 157                         unlock_buffer(bh);
 158                         ext4_error(sb, "Inode bitmap for bg 0 marked "
 159                                    "uninitialized");
 160                         err = -EFSCORRUPTED;
 161                         goto out;
 162                 }
 163                 memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
 164                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 165                                      sb->s_blocksize * 8, bh->b_data);
 166                 set_bitmap_uptodate(bh);
 167                 set_buffer_uptodate(bh);
 168                 set_buffer_verified(bh);
 169                 ext4_unlock_group(sb, block_group);
 170                 unlock_buffer(bh);
 171                 return bh;
 172         }
 173         ext4_unlock_group(sb, block_group);
 174
 175         if (buffer_uptodate(bh)) {
 176                 /*
 177                  * if not uninit if bh is uptodate,
 178                  * bitmap is also uptodate
 179                  */
 180                 set_bitmap_uptodate(bh);
 181                 unlock_buffer(bh);
 182                 goto verify;
 183         }
 184         /*
 185          * submit the buffer_head for reading
 186          */
 187         trace_ext4_load_inode_bitmap(sb, block_group);
 188         bh->b_end_io = ext4_end_bitmap_read;
 189         get_bh(bh);
 190         submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
 191         wait_on_buffer(bh);
 192         if (!buffer_uptodate(bh)) {
 193                 put_bh(bh);
 194                 ext4_error(sb, "Cannot read inode bitmap - "
 195                            "block_group = %u, inode_bitmap = %llu",
 196                            block_group, bitmap_blk);
 197                 ext4_mark_group_bitmap_corrupted(sb, block_group,
 198                                 EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 199                 return ERR_PTR(-EIO);
 200         }
 201
 202 verify:
 203         err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
 204         if (err)
 205                 goto out;
 206         return bh;
 207 out:
 208         put_bh(bh);
 209         return ERR_PTR(err);
 210 }
 211
 212 /*
 213  * NOTE! When we get the inode, we're the only people
 214  * that have access to it, and as such there are no
 215  * race conditions we have to worry about. The inode
 216  * is not on the hash-lists, and it cannot be reached
 217  * through the filesystem because the directory entry
 218  * has been deleted earlier.
 219  *
 220  * HOWEVER: we must make sure that we get no aliases,
 221  * which means that we have to call "clear_inode()"
 222  * _before_ we mark the inode not in use in the inode
 223  * bitmaps. Otherwise a newly created file might use
 224  * the same inode number (not actually the same pointer
 225  * though), and then we'd have two inodes sharing the
 226  * same inode number and space on the harddisk.
 227  */
 228 void ext4_free_inode(handle_t *handle, struct inode *inode)
 229 {
 230         struct super_block *sb = inode->i_sb;
 231         int is_directory;
 232         unsigned long ino;
 233         struct buffer_head *bitmap_bh = NULL;
 234         struct buffer_head *bh2;
 235         ext4_group_t block_group;
 236         unsigned long bit;
 237         struct ext4_group_desc *gdp;
 238         struct ext4_super_block *es;
 239         struct ext4_sb_info *sbi;
 240         int fatal = 0, err, count, cleared;
 241         struct ext4_group_info *grp;
 242
 243         if (!sb) {
 244                 printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
 245                        "nonexistent device\n", __func__, __LINE__);
 246                 return;
 247         }
 248         if (atomic_read(&inode->i_count) > 1) {
 249                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
 250                          __func__, __LINE__, inode->i_ino,
 251                          atomic_read(&inode->i_count));
 252                 return;
 253         }
 254         if (inode->i_nlink) {
 255                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
 256                          __func__, __LINE__, inode->i_ino, inode->i_nlink);
 257                 return;
 258         }
 259         sbi = EXT4_SB(sb);
 260
 261         ino = inode->i_ino;
 262         ext4_debug("freeing inode %lu\n", ino);
 263         trace_ext4_free_inode(inode);
 264
 265         /*
 266          * Note: we must free any quota before locking the superblock,
 267          * as writing the quota to disk may need the lock as well.
 268          */
 269         dquot_initialize(inode);
 270         dquot_free_inode(inode);
 271         dquot_drop(inode);
 272
 273         is_directory = S_ISDIR(inode->i_mode);
 274
 275         /* Do this BEFORE marking the inode not in use or returning an error */
 276         ext4_clear_inode(inode);
 277
 278         es = sbi->s_es;
 279         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 280                 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
 281                 goto error_return;
 282         }
 283         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 284         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 285         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 286         /* Don't bother if the inode bitmap is corrupt. */
 287         grp = ext4_get_group_info(sb, block_group);
 288         if (IS_ERR(bitmap_bh)) {
 289                 fatal = PTR_ERR(bitmap_bh);
 290                 bitmap_bh = NULL;
 291                 goto error_return;
 292         }
 293         if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
 294                 fatal = -EFSCORRUPTED;
 295                 goto error_return;
 296         }
 297
 298         BUFFER_TRACE(bitmap_bh, "get_write_access");
 299         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 300         if (fatal)
 301                 goto error_return;
 302
 303         fatal = -ESRCH;
 304         gdp = ext4_get_group_desc(sb, block_group, &bh2);
 305         if (gdp) {
 306                 BUFFER_TRACE(bh2, "get_write_access");
 307                 fatal = ext4_journal_get_write_access(handle, bh2);
 308         }
 309         ext4_lock_group(sb, block_group);
 310         cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
 311         if (fatal || !cleared) {
 312                 ext4_unlock_group(sb, block_group);
 313                 goto out;
 314         }
 315
 316         count = ext4_free_inodes_count(sb, gdp) + 1;
 317         ext4_free_inodes_set(sb, gdp, count);
 318         if (is_directory) {
 319                 count = ext4_used_dirs_count(sb, gdp) - 1;
 320                 ext4_used_dirs_set(sb, gdp, count);
 321                 percpu_counter_dec(&sbi->s_dirs_counter);
 322         }
 323         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
 324                                    EXT4_INODES_PER_GROUP(sb) / 8);
 325         ext4_group_desc_csum_set(sb, block_group, gdp);
 326         ext4_unlock_group(sb, block_group);
 327
 328         percpu_counter_inc(&sbi->s_freeinodes_counter);
 329         if (sbi->s_log_groups_per_flex) {
 330                 ext4_group_t f = ext4_flex_group(sbi, block_group);
 331
 332                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 333                 if (is_directory)
 334                         atomic_dec(&sbi->s_flex_groups[f].used_dirs);
 335         }
 336         BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 337         fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
 338 out:
 339         if (cleared) {
 340                 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 341                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 342                 if (!fatal)
 343                         fatal = err;
 344         } else {
 345                 ext4_error(sb, "bit already cleared for inode %lu", ino);
 346                 ext4_mark_group_bitmap_corrupted(sb, block_group,
 347                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 348         }
 349
 350 error_return:
 351         brelse(bitmap_bh);
 352         ext4_std_error(sb, fatal);
 353 }
 354
 355 struct orlov_stats {
 356         __u64 free_clusters;
 357         __u32 free_inodes;
 358         __u32 used_dirs;
 359 };
 360
 361 /*
 362  * Helper function for Orlov's allocator; returns critical information
 363  * for a particular block group or flex_bg.  If flex_size is 1, then g
 364  * is a block group number; otherwise it is flex_bg number.
 365  */
 366 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 367                             int flex_size, struct orlov_stats *stats)
 368 {
 369         struct ext4_group_desc *desc;
 370         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
 371
 372         if (flex_size > 1) {
 373                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
 374                 stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
 375                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
 376                 return;
 377         }
 378
 379         desc = ext4_get_group_desc(sb, g, NULL);
 380         if (desc) {
 381                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
 382                 stats->free_clusters = ext4_free_group_clusters(sb, desc);
 383                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
 384         } else {
 385                 stats->free_inodes = 0;
 386                 stats->free_clusters = 0;
 387                 stats->used_dirs = 0;
 388         }
 389 }
 390
 391 /*
 392  * Orlov's allocator for directories.
 393  *
 394  * We always try to spread first-level directories.
 395  *
 396  * If there are blockgroups with both free inodes and free blocks counts
 397  * not worse than average we return one with smallest directory count.
 398  * Otherwise we simply return a random group.
 399  *
 400  * For the rest rules look so:
 401  *
 402  * It's OK to put directory into a group unless
 403  * it has too many directories already (max_dirs) or
 404  * it has too few free inodes left (min_inodes) or
 405  * it has too few free blocks left (min_blocks) or
 406  * Parent's group is preferred, if it doesn't satisfy these
 407  * conditions we search cyclically through the rest. If none
 408  * of the groups look good we just look for a group with more
 409  * free inodes than average (starting at parent's group).
 410  */
 411
 412 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 413                             ext4_group_t *group, umode_t mode,
 414                             const struct qstr *qstr)
 415 {
 416         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 417         struct ext4_sb_info *sbi = EXT4_SB(sb);
 418         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 419         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 420         unsigned int freei, avefreei, grp_free;
 421         ext4_fsblk_t freeb, avefreec;
 422         unsigned int ndirs;
 423         int max_dirs, min_inodes;
 424         ext4_grpblk_t min_clusters;
 425         ext4_group_t i, grp, g, ngroups;
 426         struct ext4_group_desc *desc;
 427         struct orlov_stats stats;
 428         int flex_size = ext4_flex_bg_size(sbi);
 429         struct dx_hash_info hinfo;
 430
 431         ngroups = real_ngroups;
 432         if (flex_size > 1) {
 433                 ngroups = (real_ngroups + flex_size - 1) >>
 434                         sbi->s_log_groups_per_flex;
 435                 parent_group >>= sbi->s_log_groups_per_flex;
 436         }
 437
 438         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 439         avefreei = freei / ngroups;
 440         freeb = EXT4_C2B(sbi,
 441                 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
 442         avefreec = freeb;
 443         do_div(avefreec, ngroups);
 444         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 445
 446         if (S_ISDIR(mode) &&
 447             ((parent == d_inode(sb->s_root)) ||
 448              (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
 449                 int best_ndir = inodes_per_group;
 450                 int ret = -1;
 451
 452                 if (qstr) {
 453                         hinfo.hash_version = DX_HASH_HALF_MD4;
 454                         hinfo.seed = sbi->s_hash_seed;
 455                         ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
 456                         grp = hinfo.hash;
 457                 } else
 458                         grp = prandom_u32();
 459                 parent_group = (unsigned)grp % ngroups;
 460                 for (i = 0; i < ngroups; i++) {
 461                         g = (parent_group + i) % ngroups;
 462                         get_orlov_stats(sb, g, flex_size, &stats);
 463                         if (!stats.free_inodes)
 464                                 continue;
 465                         if (stats.used_dirs >= best_ndir)
 466                                 continue;
 467                         if (stats.free_inodes < avefreei)
 468                                 continue;
 469                         if (stats.free_clusters < avefreec)
 470                                 continue;
 471                         grp = g;
 472                         ret = 0;
 473                         best_ndir = stats.used_dirs;
 474                 }
 475                 if (ret)
 476                         goto fallback;
 477         found_flex_bg:
 478                 if (flex_size == 1) {
 479                         *group = grp;
 480                         return 0;
 481                 }
 482
 483                 /*
 484                  * We pack inodes at the beginning of the flexgroup's
 485                  * inode tables.  Block allocation decisions will do
 486                  * something similar, although regular files will
 487                  * start at 2nd block group of the flexgroup.  See
 488                  * ext4_ext_find_goal() and ext4_find_near().
 489                  */
 490                 grp *= flex_size;
 491                 for (i = 0; i < flex_size; i++) {
 492                         if (grp+i >= real_ngroups)
 493                                 break;
 494                         desc = ext4_get_group_desc(sb, grp+i, NULL);
 495                         if (desc && ext4_free_inodes_count(sb, desc)) {
 496                                 *group = grp+i;
 497                                 return 0;
 498                         }
 499                 }
 500                 goto fallback;
 501         }
 502
 503         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 504         min_inodes = avefreei - inodes_per_group*flex_size / 4;
 505         if (min_inodes < 1)
 506                 min_inodes = 1;
 507         min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
 508
 509         /*
 510          * Start looking in the flex group where we last allocated an
 511          * inode for this parent directory
 512          */
 513         if (EXT4_I(parent)->i_last_alloc_group != ~0) {
 514                 parent_group = EXT4_I(parent)->i_last_alloc_group;
 515                 if (flex_size > 1)
 516                         parent_group >>= sbi->s_log_groups_per_flex;
 517         }
 518
 519         for (i = 0; i < ngroups; i++) {
 520                 grp = (parent_group + i) % ngroups;
 521                 get_orlov_stats(sb, grp, flex_size, &stats);
 522                 if (stats.used_dirs >= max_dirs)
 523                         continue;
 524                 if (stats.free_inodes < min_inodes)
 525                         continue;
 526                 if (stats.free_clusters < min_clusters)
 527                         continue;
 528                 goto found_flex_bg;
 529         }
 530
 531 fallback:
 532         ngroups = real_ngroups;
 533         avefreei = freei / ngroups;
 534 fallback_retry:
 535         parent_group = EXT4_I(parent)->i_block_group;
 536         for (i = 0; i < ngroups; i++) {
 537                 grp = (parent_group + i) % ngroups;
 538                 desc = ext4_get_group_desc(sb, grp, NULL);
 539                 if (desc) {
 540                         grp_free = ext4_free_inodes_count(sb, desc);
 541                         if (grp_free && grp_free >= avefreei) {
 542                                 *group = grp;
 543                                 return 0;
 544                         }
 545                 }
 546         }
 547
 548         if (avefreei) {
 549                 /*
 550                  * The free-inodes counter is approximate, and for really small
 551                  * filesystems the above test can fail to find any blockgroups
 552                  */
 553                 avefreei = 0;
 554                 goto fallback_retry;
 555         }
 556
 557         return -1;
 558 }
 559
 560 static int find_group_other(struct super_block *sb, struct inode *parent,
 561                             ext4_group_t *group, umode_t mode)
 562 {
 563         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 564         ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
 565         struct ext4_group_desc *desc;
 566         int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
 567
 568         /*
 569          * Try to place the inode is the same flex group as its
 570          * parent.  If we can't find space, use the Orlov algorithm to
 571          * find another flex group, and store that information in the
 572          * parent directory's inode information so that use that flex
 573          * group for future allocations.
 574          */
 575         if (flex_size > 1) {
 576                 int retry = 0;
 577
 578         try_again:
 579                 parent_group &= ~(flex_size-1);
 580                 last = parent_group + flex_size;
 581                 if (last > ngroups)
 582                         last = ngroups;
 583                 for  (i = parent_group; i < last; i++) {
 584                         desc = ext4_get_group_desc(sb, i, NULL);
 585                         if (desc && ext4_free_inodes_count(sb, desc)) {
 586                                 *group = i;
 587                                 return 0;
 588                         }
 589                 }
 590                 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
 591                         retry = 1;
 592                         parent_group = EXT4_I(parent)->i_last_alloc_group;
 593                         goto try_again;
 594                 }
 595                 /*
 596                  * If this didn't work, use the Orlov search algorithm
 597                  * to find a new flex group; we pass in the mode to
 598                  * avoid the topdir algorithms.
 599                  */
 600                 *group = parent_group + flex_size;
 601                 if (*group > ngroups)
 602                         *group = 0;
 603                 return find_group_orlov(sb, parent, group, mode, NULL);
 604         }
 605
 606         /*
 607          * Try to place the inode in its parent directory
 608          */
 609         *group = parent_group;
 610         desc = ext4_get_group_desc(sb, *group, NULL);
 611         if (desc && ext4_free_inodes_count(sb, desc) &&
 612             ext4_free_group_clusters(sb, desc))
 613                 return 0;
 614
 615         /*
 616          * We're going to place this inode in a different blockgroup from its
 617          * parent.  We want to cause files in a common directory to all land in
 618          * the same blockgroup.  But we want files which are in a different
 619          * directory which shares a blockgroup with our parent to land in a
 620          * different blockgroup.
 621          *
 622          * So add our directory's i_ino into the starting point for the hash.
 623          */
 624         *group = (*group + parent->i_ino) % ngroups;
 625
 626         /*
 627          * Use a quadratic hash to find a group with a free inode and some free
 628          * blocks.
 629          */
 630         for (i = 1; i < ngroups; i <<= 1) {
 631                 *group += i;
 632                 if (*group >= ngroups)
 633                         *group -= ngroups;
 634                 desc = ext4_get_group_desc(sb, *group, NULL);
 635                 if (desc && ext4_free_inodes_count(sb, desc) &&
 636                     ext4_free_group_clusters(sb, desc))
 637                         return 0;
 638         }
 639
 640         /*
 641          * That failed: try linear search for a free inode, even if that group
 642          * has no free blocks.
 643          */
 644         *group = parent_group;
 645         for (i = 0; i < ngroups; i++) {
 646                 if (++*group >= ngroups)
 647                         *group = 0;
 648                 desc = ext4_get_group_desc(sb, *group, NULL);
 649                 if (desc && ext4_free_inodes_count(sb, desc))
 650                         return 0;
 651         }
 652
 653         return -1;
 654 }
 655
 656 /*
 657  * In no journal mode, if an inode has recently been deleted, we want
 658  * to avoid reusing it until we're reasonably sure the inode table
 659  * block has been written back to disk.  (Yes, these values are
 660  * somewhat arbitrary...)
 661  */
 662 #define RECENTCY_MIN    5
 663 #define RECENTCY_DIRTY  300
 664
 665 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
 666 {
 667         struct ext4_group_desc  *gdp;
 668         struct ext4_inode       *raw_inode;
 669         struct buffer_head      *bh;
 670         int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
 671         int offset, ret = 0;
 672         int recentcy = RECENTCY_MIN;
 673         u32 dtime, now;
 674
 675         gdp = ext4_get_group_desc(sb, group, NULL);
 676         if (unlikely(!gdp))
 677                 return 0;
 678
 679         bh = sb_find_get_block(sb, ext4_inode_table(sb, gdp) +
 680                        (ino / inodes_per_block));
 681         if (!bh || !buffer_uptodate(bh))
 682                 /*
 683                  * If the block is not in the buffer cache, then it
 684                  * must have been written out.
 685                  */
 686                 goto out;
 687
 688         offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
 689         raw_inode = (struct ext4_inode *) (bh->b_data + offset);
 690
 691         /* i_dtime is only 32 bits on disk, but we only care about relative
 692          * times in the range of a few minutes (i.e. long enough to sync a
 693          * recently-deleted inode to disk), so using the low 32 bits of the
 694          * clock (a 68 year range) is enough, see time_before32() */
 695         dtime = le32_to_cpu(raw_inode->i_dtime);
 696         now = ktime_get_real_seconds();
 697         if (buffer_dirty(bh))
 698                 recentcy += RECENTCY_DIRTY;
 699
 700         if (dtime && time_before32(dtime, now) &&
 701             time_before32(now, dtime + recentcy))
 702                 ret = 1;
 703 out:
 704         brelse(bh);
 705         return ret;
 706 }
 707
 708 static int find_inode_bit(struct super_block *sb, ext4_group_t group,
 709                           struct buffer_head *bitmap, unsigned long *ino)
 710 {
 711 next:
 712         *ino = ext4_find_next_zero_bit((unsigned long *)
 713                                        bitmap->b_data,
 714                                        EXT4_INODES_PER_GROUP(sb), *ino);
 715         if (*ino >= EXT4_INODES_PER_GROUP(sb))
 716                 return 0;
 717
 718         if ((EXT4_SB(sb)->s_journal == NULL) &&
 719             recently_deleted(sb, group, *ino)) {
 720                 *ino = *ino + 1;
 721                 if (*ino < EXT4_INODES_PER_GROUP(sb))
 722                         goto next;
 723                 return 0;
 724         }
 725
 726         return 1;
 727 }
 728
 729 /*
 730  * There are two policies for allocating an inode.  If the new inode is
 731  * a directory, then a forward search is made for a block group with both
 732  * free space and a low directory-to-inode ratio; if that fails, then of
 733  * the groups with above-average free space, that group with the fewest
 734  * directories already is chosen.
 735  *
 736  * For other inodes, search forward from the parent directory's block
 737  * group to find a free inode.
 738  */
 739 struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 740                                umode_t mode, const struct qstr *qstr,
 741                                __u32 goal, uid_t *owner, __u32 i_flags,
 742                                int handle_type, unsigned int line_no,
 743                                int nblocks)
 744 {
 745         struct super_block *sb;
 746         struct buffer_head *inode_bitmap_bh = NULL;
 747         struct buffer_head *group_desc_bh;
 748         ext4_group_t ngroups, group = 0;
 749         unsigned long ino = 0;
 750         struct inode *inode;
 751         struct ext4_group_desc *gdp = NULL;
 752         struct ext4_inode_info *ei;
 753         struct ext4_sb_info *sbi;
 754         int ret2, err;
 755         struct inode *ret;
 756         ext4_group_t i;
 757         ext4_group_t flex_group;
 758         struct ext4_group_info *grp;
 759         int encrypt = 0;
 760
 761         /* Cannot create files in a deleted directory */
 762         if (!dir || !dir->i_nlink)
 763                 return ERR_PTR(-EPERM);
 764
 765         sb = dir->i_sb;
 766         sbi = EXT4_SB(sb);
 767
 768         if (unlikely(ext4_forced_shutdown(sbi)))
 769                 return ERR_PTR(-EIO);
 770
 771         if ((ext4_encrypted_inode(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) &&
 772             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) &&
 773             !(i_flags & EXT4_EA_INODE_FL)) {
 774                 err = fscrypt_get_encryption_info(dir);
 775                 if (err)
 776                         return ERR_PTR(err);
 777                 if (!fscrypt_has_encryption_key(dir))
 778                         return ERR_PTR(-ENOKEY);
 779                 encrypt = 1;
 780         }
 781
 782         if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
 783 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 784                 struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
 785
 786                 if (IS_ERR(p))
 787                         return ERR_CAST(p);
 788                 if (p) {
 789                         int acl_size = p->a_count * sizeof(ext4_acl_entry);
 790
 791                         nblocks += (S_ISDIR(mode) ? 2 : 1) *
 792                                 __ext4_xattr_set_credits(sb, NULL /* inode */,
 793                                         NULL /* block_bh */, acl_size,
 794                                         true /* is_create */);
 795                         posix_acl_release(p);
 796                 }
 797 #endif
 798
 799 #ifdef CONFIG_SECURITY
 800                 {
 801                         int num_security_xattrs = 1;
 802
 803 #ifdef CONFIG_INTEGRITY
 804                         num_security_xattrs++;
 805 #endif
 806                         /*
 807                          * We assume that security xattrs are never
 808                          * more than 1k.  In practice they are under
 809                          * 128 bytes.
 810                          */
 811                         nblocks += num_security_xattrs *
 812                                 __ext4_xattr_set_credits(sb, NULL /* inode */,
 813                                         NULL /* block_bh */, 1024,
 814                                         true /* is_create */);
 815                 }
 816 #endif
 817                 if (encrypt)
 818                         nblocks += __ext4_xattr_set_credits(sb,
 819                                         NULL /* inode */, NULL /* block_bh */,
 820                                         FSCRYPT_SET_CONTEXT_MAX_SIZE,
 821                                         true /* is_create */);
 822         }
 823
 824         ngroups = ext4_get_groups_count(sb);
 825         trace_ext4_request_inode(dir, mode);
 826         inode = new_inode(sb);
 827         if (!inode)
 828                 return ERR_PTR(-ENOMEM);
 829         ei = EXT4_I(inode);
 830
 831         /*
 832          * Initialize owners and quota early so that we don't have to account
 833          * for quota initialization worst case in standard inode creating
 834          * transaction
 835          */
 836         if (owner) {
 837                 inode->i_mode = mode;
 838                 i_uid_write(inode, owner[0]);
 839                 i_gid_write(inode, owner[1]);
 840         } else if (test_opt(sb, GRPID)) {
 841                 inode->i_mode = mode;
 842                 inode->i_uid = current_fsuid();
 843                 inode->i_gid = dir->i_gid;
 844         } else
 845                 inode_init_owner(inode, dir, mode);
 846
 847         if (ext4_has_feature_project(sb) &&
 848             ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
 849                 ei->i_projid = EXT4_I(dir)->i_projid;
 850         else
 851                 ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
 852
 853         err = dquot_initialize(inode);
 854         if (err)
 855                 goto out;
 856
 857         if (!goal)
 858                 goal = sbi->s_inode_goal;
 859
 860         if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
 861                 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
 862                 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
 863                 ret2 = 0;
 864                 goto got_group;
 865         }
 866
 867         if (S_ISDIR(mode))
 868                 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
 869         else
 870                 ret2 = find_group_other(sb, dir, &group, mode);
 871
 872 got_group:
 873         EXT4_I(dir)->i_last_alloc_group = group;
 874         err = -ENOSPC;
 875         if (ret2 == -1)
 876                 goto out;
 877
 878         /*
 879          * Normally we will only go through one pass of this loop,
 880          * unless we get unlucky and it turns out the group we selected
 881          * had its last inode grabbed by someone else.
 882          */
 883         for (i = 0; i < ngroups; i++, ino = 0) {
 884                 err = -EIO;
 885
 886                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 887                 if (!gdp)
 888                         goto out;
 889
 890                 /*
 891                  * Check free inodes count before loading bitmap.
 892                  */
 893                 if (ext4_free_inodes_count(sb, gdp) == 0)
 894                         goto next_group;
 895
 896                 grp = ext4_get_group_info(sb, group);
 897                 /* Skip groups with already-known suspicious inode tables */
 898                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
 899                         goto next_group;
 900
 901                 brelse(inode_bitmap_bh);
 902                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 903                 /* Skip groups with suspicious inode tables */
 904                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
 905                     IS_ERR(inode_bitmap_bh)) {
 906                         inode_bitmap_bh = NULL;
 907                         goto next_group;
 908                 }
 909
 910 repeat_in_this_group:
 911                 ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
 912                 if (!ret2)
 913                         goto next_group;
 914
 915                 if (group == 0 && (ino + 1) < EXT4_FIRST_INO(sb)) {
 916                         ext4_error(sb, "reserved inode found cleared - "
 917                                    "inode=%lu", ino + 1);
 918                         ext4_mark_group_bitmap_corrupted(sb, group,
 919                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 920                         goto next_group;
 921                 }
 922
 923                 if (!handle) {
 924                         BUG_ON(nblocks <= 0);
 925                         handle = __ext4_journal_start_sb(dir->i_sb, line_no,
 926                                                          handle_type, nblocks,
 927                                                          0);
 928                         if (IS_ERR(handle)) {
 929                                 err = PTR_ERR(handle);
 930                                 ext4_std_error(sb, err);
 931                                 goto out;
 932                         }
 933                 }
 934                 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 935                 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
 936                 if (err) {
 937                         ext4_std_error(sb, err);
 938                         goto out;
 939                 }
 940                 ext4_lock_group(sb, group);
 941                 ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
 942                 if (ret2) {
 943                         /* Someone already took the bit. Repeat the search
 944                          * with lock held.
 945                          */
 946                         ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
 947                         if (ret2) {
 948                                 ext4_set_bit(ino, inode_bitmap_bh->b_data);
 949                                 ret2 = 0;
 950                         } else {
 951                                 ret2 = 1; /* we didn't grab the inode */
 952                         }
 953                 }
 954                 ext4_unlock_group(sb, group);
 955                 ino++;          /* the inode bitmap is zero-based */
 956                 if (!ret2)
 957                         goto got; /* we grabbed the inode! */
 958
 959                 if (ino < EXT4_INODES_PER_GROUP(sb))
 960                         goto repeat_in_this_group;
 961 next_group:
 962                 if (++group == ngroups)
 963                         group = 0;
 964         }
 965         err = -ENOSPC;
 966         goto out;
 967
 968 got:
 969         BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
 970         err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
 971         if (err) {
 972                 ext4_std_error(sb, err);
 973                 goto out;
 974         }
 975
 976         BUFFER_TRACE(group_desc_bh, "get_write_access");
 977         err = ext4_journal_get_write_access(handle, group_desc_bh);
 978         if (err) {
 979                 ext4_std_error(sb, err);
 980                 goto out;
 981         }
 982
 983         /* We may have to initialize the block bitmap if it isn't already */
 984         if (ext4_has_group_desc_csum(sb) &&
 985             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 986                 struct buffer_head *block_bitmap_bh;
 987
 988                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 989                 if (IS_ERR(block_bitmap_bh)) {
 990                         err = PTR_ERR(block_bitmap_bh);
 991                         goto out;
 992                 }
 993                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 994                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 995                 if (err) {
 996                         brelse(block_bitmap_bh);
 997                         ext4_std_error(sb, err);
 998                         goto out;
 999                 }
1000
1001                 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
1002                 err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
1003
1004                 /* recheck and clear flag under lock if we still need to */
1005                 ext4_lock_group(sb, group);
1006                 if (ext4_has_group_desc_csum(sb) &&
1007                     (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
1008                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
1009                         ext4_free_group_clusters_set(sb, gdp,
1010                                 ext4_free_clusters_after_init(sb, group, gdp));
1011                         ext4_block_bitmap_csum_set(sb, group, gdp,
1012                                                    block_bitmap_bh);
1013                         ext4_group_desc_csum_set(sb, group, gdp);
1014                 }
1015                 ext4_unlock_group(sb, group);
1016                 brelse(block_bitmap_bh);
1017
1018                 if (err) {
1019                         ext4_std_error(sb, err);
1020                         goto out;
1021                 }
1022         }
1023
1024         /* Update the relevant bg descriptor fields */
1025         if (ext4_has_group_desc_csum(sb)) {
1026                 int free;
1027                 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1028
1029                 down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
1030                 ext4_lock_group(sb, group); /* while we modify the bg desc */
1031                 free = EXT4_INODES_PER_GROUP(sb) -
1032                         ext4_itable_unused_count(sb, gdp);
1033                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
1034                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
1035                         free = 0;
1036                 }
1037                 /*
1038                  * Check the relative inode number against the last used
1039                  * relative inode number in this group. if it is greater
1040                  * we need to update the bg_itable_unused count
1041                  */
1042                 if (ino > free)
1043                         ext4_itable_unused_set(sb, gdp,
1044                                         (EXT4_INODES_PER_GROUP(sb) - ino));
1045                 up_read(&grp->alloc_sem);
1046         } else {
1047                 ext4_lock_group(sb, group);
1048         }
1049
1050         ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1051         if (S_ISDIR(mode)) {
1052                 ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1053                 if (sbi->s_log_groups_per_flex) {
1054                         ext4_group_t f = ext4_flex_group(sbi, group);
1055
1056                         atomic_inc(&sbi->s_flex_groups[f].used_dirs);
1057                 }
1058         }
1059         if (ext4_has_group_desc_csum(sb)) {
1060                 ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1061                                            EXT4_INODES_PER_GROUP(sb) / 8);
1062                 ext4_group_desc_csum_set(sb, group, gdp);
1063         }
1064         ext4_unlock_group(sb, group);
1065
1066         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1067         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1068         if (err) {
1069                 ext4_std_error(sb, err);
1070                 goto out;
1071         }
1072
1073         percpu_counter_dec(&sbi->s_freeinodes_counter);
1074         if (S_ISDIR(mode))
1075                 percpu_counter_inc(&sbi->s_dirs_counter);
1076
1077         if (sbi->s_log_groups_per_flex) {
1078                 flex_group = ext4_flex_group(sbi, group);
1079                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
1080         }
1081
1082         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1083         /* This is the optimal IO size (for stat), not the fs block size */
1084         inode->i_blocks = 0;
1085         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
1086                                                        current_time(inode);
1087
1088         memset(ei->i_data, 0, sizeof(ei->i_data));
1089         ei->i_dir_start_lookup = 0;
1090         ei->i_disksize = 0;
1091
1092         /* Don't inherit extent flag from directory, amongst others. */
1093         ei->i_flags =
1094                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1095         ei->i_flags |= i_flags;
1096         ei->i_file_acl = 0;
1097         ei->i_dtime = 0;
1098         ei->i_block_group = group;
1099         ei->i_last_alloc_group = ~0;
1100
1101         ext4_set_inode_flags(inode);
1102         if (IS_DIRSYNC(inode))
1103                 ext4_handle_sync(handle);
1104         if (insert_inode_locked(inode) < 0) {
1105                 /*
1106                  * Likely a bitmap corruption causing inode to be allocated
1107                  * twice.
1108                  */
1109                 err = -EIO;
1110                 ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1111                            inode->i_ino);
1112                 ext4_mark_group_bitmap_corrupted(sb, group,
1113                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
1114                 goto out;
1115         }
1116         inode->i_generation = prandom_u32();
1117
1118         /* Precompute checksum seed for inode metadata */
1119         if (ext4_has_metadata_csum(sb)) {
1120                 __u32 csum;
1121                 __le32 inum = cpu_to_le32(inode->i_ino);
1122                 __le32 gen = cpu_to_le32(inode->i_generation);
1123                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1124                                    sizeof(inum));
1125                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1126                                               sizeof(gen));
1127         }
1128
1129         ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1130         ext4_set_inode_state(inode, EXT4_STATE_NEW);
1131
1132         ei->i_extra_isize = sbi->s_want_extra_isize;
1133         ei->i_inline_off = 0;
1134         if (ext4_has_feature_inline_data(sb))
1135                 ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1136         ret = inode;
1137         err = dquot_alloc_inode(inode);
1138         if (err)
1139                 goto fail_drop;
1140
1141         /*
1142          * Since the encryption xattr will always be unique, create it first so
1143          * that it's less likely to end up in an external xattr block and
1144          * prevent its deduplication.
1145          */
1146         if (encrypt) {
1147                 err = fscrypt_inherit_context(dir, inode, handle, true);
1148                 if (err)
1149                         goto fail_free_drop;
1150         }
1151
1152         if (!(ei->i_flags & EXT4_EA_INODE_FL)) {
1153                 err = ext4_init_acl(handle, inode, dir);
1154                 if (err)
1155                         goto fail_free_drop;
1156
1157                 err = ext4_init_security(handle, inode, dir, qstr);
1158                 if (err)
1159                         goto fail_free_drop;
1160         }
1161
1162         if (ext4_has_feature_extents(sb)) {
1163                 /* set extent flag only for directory, file and normal symlink*/
1164                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1165                         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1166                         ext4_ext_tree_init(handle, inode);
1167                 }
1168         }
1169
1170         if (ext4_handle_valid(handle)) {
1171                 ei->i_sync_tid = handle->h_transaction->t_tid;
1172                 ei->i_datasync_tid = handle->h_transaction->t_tid;
1173         }
1174
1175         err = ext4_mark_inode_dirty(handle, inode);
1176         if (err) {
1177                 ext4_std_error(sb, err);
1178                 goto fail_free_drop;
1179         }
1180
1181         ext4_debug("allocating inode %lu\n", inode->i_ino);
1182         trace_ext4_allocate_inode(inode, dir, mode);
1183         brelse(inode_bitmap_bh);
1184         return ret;
1185
1186 fail_free_drop:
1187         dquot_free_inode(inode);
1188 fail_drop:
1189         clear_nlink(inode);
1190         unlock_new_inode(inode);
1191 out:
1192         dquot_drop(inode);
1193         inode->i_flags |= S_NOQUOTA;
1194         iput(inode);
1195         brelse(inode_bitmap_bh);
1196         return ERR_PTR(err);
1197 }
1198
1199 /* Verify that we are loading a valid orphan from disk */
1200 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1201 {
1202         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1203         ext4_group_t block_group;
1204         int bit;
1205         struct buffer_head *bitmap_bh = NULL;
1206         struct inode *inode = NULL;
1207         int err = -EFSCORRUPTED;
1208
1209         if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
1210                 goto bad_orphan;
1211
1212         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1213         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1214         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1215         if (IS_ERR(bitmap_bh))
1216                 return (struct inode *) bitmap_bh;
1217
1218         /* Having the inode bit set should be a 100% indicator that this
1219          * is a valid orphan (no e2fsck run on fs).  Orphans also include
1220          * inodes that were being truncated, so we can't check i_nlink==0.
1221          */
1222         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1223                 goto bad_orphan;
1224
1225         inode = ext4_iget(sb, ino);
1226         if (IS_ERR(inode)) {
1227                 err = PTR_ERR(inode);
1228                 ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
1229                            ino, err);
1230                 return inode;
1231         }
1232
1233         /*
1234          * If the orphans has i_nlinks > 0 then it should be able to
1235          * be truncated, otherwise it won't be removed from the orphan
1236          * list during processing and an infinite loop will result.
1237          * Similarly, it must not be a bad inode.
1238          */
1239         if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
1240             is_bad_inode(inode))
1241                 goto bad_orphan;
1242
1243         if (NEXT_ORPHAN(inode) > max_ino)
1244                 goto bad_orphan;
1245         brelse(bitmap_bh);
1246         return inode;
1247
1248 bad_orphan:
1249         ext4_error(sb, "bad orphan inode %lu", ino);
1250         if (bitmap_bh)
1251                 printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1252                        bit, (unsigned long long)bitmap_bh->b_blocknr,
1253                        ext4_test_bit(bit, bitmap_bh->b_data));
1254         if (inode) {
1255                 printk(KERN_ERR "is_bad_inode(inode)=%d\n",
1256                        is_bad_inode(inode));
1257                 printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
1258                        NEXT_ORPHAN(inode));
1259                 printk(KERN_ERR "max_ino=%lu\n", max_ino);
1260                 printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
1261                 /* Avoid freeing blocks if we got a bad deleted inode */
1262                 if (inode->i_nlink == 0)
1263                         inode->i_blocks = 0;
1264                 iput(inode);
1265         }
1266         brelse(bitmap_bh);
1267         return ERR_PTR(err);
1268 }
1269
1270 unsigned long ext4_count_free_inodes(struct super_block *sb)
1271 {
1272         unsigned long desc_count;
1273         struct ext4_group_desc *gdp;
1274         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1275 #ifdef EXT4FS_DEBUG
1276         struct ext4_super_block *es;
1277         unsigned long bitmap_count, x;
1278         struct buffer_head *bitmap_bh = NULL;
1279
1280         es = EXT4_SB(sb)->s_es;
1281         desc_count = 0;
1282         bitmap_count = 0;
1283         gdp = NULL;
1284         for (i = 0; i < ngroups; i++) {
1285                 gdp = ext4_get_group_desc(sb, i, NULL);
1286                 if (!gdp)
1287                         continue;
1288                 desc_count += ext4_free_inodes_count(sb, gdp);
1289                 brelse(bitmap_bh);
1290                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1291                 if (IS_ERR(bitmap_bh)) {
1292                         bitmap_bh = NULL;
1293                         continue;
1294                 }
1295
1296                 x = ext4_count_free(bitmap_bh->b_data,
1297                                     EXT4_INODES_PER_GROUP(sb) / 8);
1298                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1299                         (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1300                 bitmap_count += x;
1301         }
1302         brelse(bitmap_bh);
1303         printk(KERN_DEBUG "ext4_count_free_inodes: "
1304                "stored = %u, computed = %lu, %lu\n",
1305                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1306         return desc_count;
1307 #else
1308         desc_count = 0;
1309         for (i = 0; i < ngroups; i++) {
1310                 gdp = ext4_get_group_desc(sb, i, NULL);
1311                 if (!gdp)
1312                         continue;
1313                 desc_count += ext4_free_inodes_count(sb, gdp);
1314                 cond_resched();
1315         }
1316         return desc_count;
1317 #endif
1318 }
1319
1320 /* Called at mount-time, super-block is locked */
1321 unsigned long ext4_count_dirs(struct super_block * sb)
1322 {
1323         unsigned long count = 0;
1324         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1325
1326         for (i = 0; i < ngroups; i++) {
1327                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1328                 if (!gdp)
1329                         continue;
1330                 count += ext4_used_dirs_count(sb, gdp);
1331         }
1332         return count;
1333 }
1334
1335 /*
1336  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1337  * inode table. Must be called without any spinlock held. The only place
1338  * where it is called from on active part of filesystem is ext4lazyinit
1339  * thread, so we do not need any special locks, however we have to prevent
1340  * inode allocation from the current group, so we take alloc_sem lock, to
1341  * block ext4_new_inode() until we are finished.
1342  */
1343 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1344                                  int barrier)
1345 {
1346         struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1347         struct ext4_sb_info *sbi = EXT4_SB(sb);
1348         struct ext4_group_desc *gdp = NULL;
1349         struct buffer_head *group_desc_bh;
1350         handle_t *handle;
1351         ext4_fsblk_t blk;
1352         int num, ret = 0, used_blks = 0;
1353
1354         /* This should not happen, but just to be sure check this */
1355         if (sb_rdonly(sb)) {
1356                 ret = 1;
1357                 goto out;
1358         }
1359
1360         gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1361         if (!gdp)
1362                 goto out;
1363
1364         /*
1365          * We do not need to lock this, because we are the only one
1366          * handling this flag.
1367          */
1368         if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1369                 goto out;
1370
1371         handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1372         if (IS_ERR(handle)) {
1373                 ret = PTR_ERR(handle);
1374                 goto out;
1375         }
1376
1377         down_write(&grp->alloc_sem);
1378         /*
1379          * If inode bitmap was already initialized there may be some
1380          * used inodes so we need to skip blocks with used inodes in
1381          * inode table.
1382          */
1383         if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1384                 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1385                             ext4_itable_unused_count(sb, gdp)),
1386                             sbi->s_inodes_per_block);
1387
1388         if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1389                 ext4_error(sb, "Something is wrong with group %u: "
1390                            "used itable blocks: %d; "
1391                            "itable unused count: %u",
1392                            group, used_blks,
1393                            ext4_itable_unused_count(sb, gdp));
1394                 ret = 1;
1395                 goto err_out;
1396         }
1397
1398         blk = ext4_inode_table(sb, gdp) + used_blks;
1399         num = sbi->s_itb_per_group - used_blks;
1400
1401         BUFFER_TRACE(group_desc_bh, "get_write_access");
1402         ret = ext4_journal_get_write_access(handle,
1403                                             group_desc_bh);
1404         if (ret)
1405                 goto err_out;
1406
1407         /*
1408          * Skip zeroout if the inode table is full. But we set the ZEROED
1409          * flag anyway, because obviously, when it is full it does not need
1410          * further zeroing.
1411          */
1412         if (unlikely(num == 0))
1413                 goto skip_zeroout;
1414
1415         ext4_debug("going to zero out inode table in group %d\n",
1416                    group);
1417         ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1418         if (ret < 0)
1419                 goto err_out;
1420         if (barrier)
1421                 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1422
1423 skip_zeroout:
1424         ext4_lock_group(sb, group);
1425         gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1426         ext4_group_desc_csum_set(sb, group, gdp);
1427         ext4_unlock_group(sb, group);
1428
1429         BUFFER_TRACE(group_desc_bh,
1430                      "call ext4_handle_dirty_metadata");
1431         ret = ext4_handle_dirty_metadata(handle, NULL,
1432                                          group_desc_bh);
1433
1434 err_out:
1435         up_write(&grp->alloc_sem);
1436         ext4_journal_stop(handle);
1437 out:
1438         return ret;
1439 }