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 (card@masi.ibp.fr)
   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 (sct@redhat.com), 1993
  12  *  Big-endian to little-endian byte-swapping/bitmaps by
  13  *        David S. Miller (davem@caip.rutgers.edu), 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         struct ext4_sb_info *sbi = EXT4_SB(sb);
  87
  88         if (buffer_verified(bh))
  89                 return 0;
  90         if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
  91                 return -EFSCORRUPTED;
  92
  93         ext4_lock_group(sb, block_group);
  94         blk = ext4_inode_bitmap(sb, desc);
  95         if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
  96                                            EXT4_INODES_PER_GROUP(sb) / 8)) {
  97                 ext4_unlock_group(sb, block_group);
  98                 ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
  99                            "inode_bitmap = %llu", block_group, blk);
 100                 grp = ext4_get_group_info(sb, block_group);
 101                 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 102                         int count;
 103                         count = ext4_free_inodes_count(sb, desc);
 104                         percpu_counter_sub(&sbi->s_freeinodes_counter,
 105                                            count);
 106                 }
 107                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
 108                 return -EFSBADCRC;
 109         }
 110         set_buffer_verified(bh);
 111         ext4_unlock_group(sb, block_group);
 112         return 0;
 113 }
 114
 115 /*
 116  * Read the inode allocation bitmap for a given block_group, reading
 117  * into the specified slot in the superblock's bitmap cache.
 118  *
 119  * Return buffer_head of bitmap on success or NULL.
 120  */
 121 static struct buffer_head *
 122 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 123 {
 124         struct ext4_group_desc *desc;
 125         struct ext4_sb_info *sbi = EXT4_SB(sb);
 126         struct buffer_head *bh = NULL;
 127         ext4_fsblk_t bitmap_blk;
 128         int err;
 129
 130         desc = ext4_get_group_desc(sb, block_group, NULL);
 131         if (!desc)
 132                 return ERR_PTR(-EFSCORRUPTED);
 133
 134         bitmap_blk = ext4_inode_bitmap(sb, desc);
 135         if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
 136             (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
 137                 ext4_error(sb, "Invalid inode bitmap blk %llu in "
 138                            "block_group %u", bitmap_blk, block_group);
 139                 return ERR_PTR(-EFSCORRUPTED);
 140         }
 141         bh = sb_getblk(sb, bitmap_blk);
 142         if (unlikely(!bh)) {
 143                 ext4_error(sb, "Cannot read inode bitmap - "
 144                             "block_group = %u, inode_bitmap = %llu",
 145                             block_group, bitmap_blk);
 146                 return ERR_PTR(-EIO);
 147         }
 148         if (bitmap_uptodate(bh))
 149                 goto verify;
 150
 151         lock_buffer(bh);
 152         if (bitmap_uptodate(bh)) {
 153                 unlock_buffer(bh);
 154                 goto verify;
 155         }
 156
 157         ext4_lock_group(sb, block_group);
 158         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 159                 memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
 160                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 161                                      sb->s_blocksize * 8, bh->b_data);
 162                 set_bitmap_uptodate(bh);
 163                 set_buffer_uptodate(bh);
 164                 set_buffer_verified(bh);
 165                 ext4_unlock_group(sb, block_group);
 166                 unlock_buffer(bh);
 167                 return bh;
 168         }
 169         ext4_unlock_group(sb, block_group);
 170
 171         if (buffer_uptodate(bh)) {
 172                 /*
 173                  * if not uninit if bh is uptodate,
 174                  * bitmap is also uptodate
 175                  */
 176                 set_bitmap_uptodate(bh);
 177                 unlock_buffer(bh);
 178                 goto verify;
 179         }
 180         /*
 181          * submit the buffer_head for reading
 182          */
 183         trace_ext4_load_inode_bitmap(sb, block_group);
 184         bh->b_end_io = ext4_end_bitmap_read;
 185         get_bh(bh);
 186         submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
 187         wait_on_buffer(bh);
 188         if (!buffer_uptodate(bh)) {
 189                 put_bh(bh);
 190                 ext4_error(sb, "Cannot read inode bitmap - "
 191                            "block_group = %u, inode_bitmap = %llu",
 192                            block_group, bitmap_blk);
 193                 return ERR_PTR(-EIO);
 194         }
 195
 196 verify:
 197         err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
 198         if (err)
 199                 goto out;
 200         return bh;
 201 out:
 202         put_bh(bh);
 203         return ERR_PTR(err);
 204 }
 205
 206 /*
 207  * NOTE! When we get the inode, we're the only people
 208  * that have access to it, and as such there are no
 209  * race conditions we have to worry about. The inode
 210  * is not on the hash-lists, and it cannot be reached
 211  * through the filesystem because the directory entry
 212  * has been deleted earlier.
 213  *
 214  * HOWEVER: we must make sure that we get no aliases,
 215  * which means that we have to call "clear_inode()"
 216  * _before_ we mark the inode not in use in the inode
 217  * bitmaps. Otherwise a newly created file might use
 218  * the same inode number (not actually the same pointer
 219  * though), and then we'd have two inodes sharing the
 220  * same inode number and space on the harddisk.
 221  */
 222 void ext4_free_inode(handle_t *handle, struct inode *inode)
 223 {
 224         struct super_block *sb = inode->i_sb;
 225         int is_directory;
 226         unsigned long ino;
 227         struct buffer_head *bitmap_bh = NULL;
 228         struct buffer_head *bh2;
 229         ext4_group_t block_group;
 230         unsigned long bit;
 231         struct ext4_group_desc *gdp;
 232         struct ext4_super_block *es;
 233         struct ext4_sb_info *sbi;
 234         int fatal = 0, err, count, cleared;
 235         struct ext4_group_info *grp;
 236
 237         if (!sb) {
 238                 printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
 239                        "nonexistent device\n", __func__, __LINE__);
 240                 return;
 241         }
 242         if (atomic_read(&inode->i_count) > 1) {
 243                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
 244                          __func__, __LINE__, inode->i_ino,
 245                          atomic_read(&inode->i_count));
 246                 return;
 247         }
 248         if (inode->i_nlink) {
 249                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
 250                          __func__, __LINE__, inode->i_ino, inode->i_nlink);
 251                 return;
 252         }
 253         sbi = EXT4_SB(sb);
 254
 255         ino = inode->i_ino;
 256         ext4_debug("freeing inode %lu\n", ino);
 257         trace_ext4_free_inode(inode);
 258
 259         /*
 260          * Note: we must free any quota before locking the superblock,
 261          * as writing the quota to disk may need the lock as well.
 262          */
 263         dquot_initialize(inode);
 264         dquot_free_inode(inode);
 265         dquot_drop(inode);
 266
 267         is_directory = S_ISDIR(inode->i_mode);
 268
 269         /* Do this BEFORE marking the inode not in use or returning an error */
 270         ext4_clear_inode(inode);
 271
 272         es = sbi->s_es;
 273         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 274                 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
 275                 goto error_return;
 276         }
 277         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 278         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 279         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 280         /* Don't bother if the inode bitmap is corrupt. */
 281         grp = ext4_get_group_info(sb, block_group);
 282         if (IS_ERR(bitmap_bh)) {
 283                 fatal = PTR_ERR(bitmap_bh);
 284                 bitmap_bh = NULL;
 285                 goto error_return;
 286         }
 287         if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
 288                 fatal = -EFSCORRUPTED;
 289                 goto error_return;
 290         }
 291
 292         BUFFER_TRACE(bitmap_bh, "get_write_access");
 293         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 294         if (fatal)
 295                 goto error_return;
 296
 297         fatal = -ESRCH;
 298         gdp = ext4_get_group_desc(sb, block_group, &bh2);
 299         if (gdp) {
 300                 BUFFER_TRACE(bh2, "get_write_access");
 301                 fatal = ext4_journal_get_write_access(handle, bh2);
 302         }
 303         ext4_lock_group(sb, block_group);
 304         cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
 305         if (fatal || !cleared) {
 306                 ext4_unlock_group(sb, block_group);
 307                 goto out;
 308         }
 309
 310         count = ext4_free_inodes_count(sb, gdp) + 1;
 311         ext4_free_inodes_set(sb, gdp, count);
 312         if (is_directory) {
 313                 count = ext4_used_dirs_count(sb, gdp) - 1;
 314                 ext4_used_dirs_set(sb, gdp, count);
 315                 percpu_counter_dec(&sbi->s_dirs_counter);
 316         }
 317         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
 318                                    EXT4_INODES_PER_GROUP(sb) / 8);
 319         ext4_group_desc_csum_set(sb, block_group, gdp);
 320         ext4_unlock_group(sb, block_group);
 321
 322         percpu_counter_inc(&sbi->s_freeinodes_counter);
 323         if (sbi->s_log_groups_per_flex) {
 324                 ext4_group_t f = ext4_flex_group(sbi, block_group);
 325
 326                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 327                 if (is_directory)
 328                         atomic_dec(&sbi->s_flex_groups[f].used_dirs);
 329         }
 330         BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 331         fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
 332 out:
 333         if (cleared) {
 334                 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 335                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 336                 if (!fatal)
 337                         fatal = err;
 338         } else {
 339                 ext4_error(sb, "bit already cleared for inode %lu", ino);
 340                 if (gdp && !EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 341                         int count;
 342                         count = ext4_free_inodes_count(sb, gdp);
 343                         percpu_counter_sub(&sbi->s_freeinodes_counter,
 344                                            count);
 345                 }
 346                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
 347         }
 348
 349 error_return:
 350         brelse(bitmap_bh);
 351         ext4_std_error(sb, fatal);
 352 }
 353
 354 struct orlov_stats {
 355         __u64 free_clusters;
 356         __u32 free_inodes;
 357         __u32 used_dirs;
 358 };
 359
 360 /*
 361  * Helper function for Orlov's allocator; returns critical information
 362  * for a particular block group or flex_bg.  If flex_size is 1, then g
 363  * is a block group number; otherwise it is flex_bg number.
 364  */
 365 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 366                             int flex_size, struct orlov_stats *stats)
 367 {
 368         struct ext4_group_desc *desc;
 369         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
 370
 371         if (flex_size > 1) {
 372                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
 373                 stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
 374                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
 375                 return;
 376         }
 377
 378         desc = ext4_get_group_desc(sb, g, NULL);
 379         if (desc) {
 380                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
 381                 stats->free_clusters = ext4_free_group_clusters(sb, desc);
 382                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
 383         } else {
 384                 stats->free_inodes = 0;
 385                 stats->free_clusters = 0;
 386                 stats->used_dirs = 0;
 387         }
 388 }
 389
 390 /*
 391  * Orlov's allocator for directories.
 392  *
 393  * We always try to spread first-level directories.
 394  *
 395  * If there are blockgroups with both free inodes and free blocks counts
 396  * not worse than average we return one with smallest directory count.
 397  * Otherwise we simply return a random group.
 398  *
 399  * For the rest rules look so:
 400  *
 401  * It's OK to put directory into a group unless
 402  * it has too many directories already (max_dirs) or
 403  * it has too few free inodes left (min_inodes) or
 404  * it has too few free blocks left (min_blocks) or
 405  * Parent's group is preferred, if it doesn't satisfy these
 406  * conditions we search cyclically through the rest. If none
 407  * of the groups look good we just look for a group with more
 408  * free inodes than average (starting at parent's group).
 409  */
 410
 411 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 412                             ext4_group_t *group, umode_t mode,
 413                             const struct qstr *qstr)
 414 {
 415         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 416         struct ext4_sb_info *sbi = EXT4_SB(sb);
 417         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 418         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 419         unsigned int freei, avefreei, grp_free;
 420         ext4_fsblk_t freeb, avefreec;
 421         unsigned int ndirs;
 422         int max_dirs, min_inodes;
 423         ext4_grpblk_t min_clusters;
 424         ext4_group_t i, grp, g, ngroups;
 425         struct ext4_group_desc *desc;
 426         struct orlov_stats stats;
 427         int flex_size = ext4_flex_bg_size(sbi);
 428         struct dx_hash_info hinfo;
 429
 430         ngroups = real_ngroups;
 431         if (flex_size > 1) {
 432                 ngroups = (real_ngroups + flex_size - 1) >>
 433                         sbi->s_log_groups_per_flex;
 434                 parent_group >>= sbi->s_log_groups_per_flex;
 435         }
 436
 437         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 438         avefreei = freei / ngroups;
 439         freeb = EXT4_C2B(sbi,
 440                 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
 441         avefreec = freeb;
 442         do_div(avefreec, ngroups);
 443         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 444
 445         if (S_ISDIR(mode) &&
 446             ((parent == d_inode(sb->s_root)) ||
 447              (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
 448                 int best_ndir = inodes_per_group;
 449                 int ret = -1;
 450
 451                 if (qstr) {
 452                         hinfo.hash_version = DX_HASH_HALF_MD4;
 453                         hinfo.seed = sbi->s_hash_seed;
 454                         ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
 455                         grp = hinfo.hash;
 456                 } else
 457                         grp = prandom_u32();
 458                 parent_group = (unsigned)grp % ngroups;
 459                 for (i = 0; i < ngroups; i++) {
 460                         g = (parent_group + i) % ngroups;
 461                         get_orlov_stats(sb, g, flex_size, &stats);
 462                         if (!stats.free_inodes)
 463                                 continue;
 464                         if (stats.used_dirs >= best_ndir)
 465                                 continue;
 466                         if (stats.free_inodes < avefreei)
 467                                 continue;
 468                         if (stats.free_clusters < avefreec)
 469                                 continue;
 470                         grp = g;
 471                         ret = 0;
 472                         best_ndir = stats.used_dirs;
 473                 }
 474                 if (ret)
 475                         goto fallback;
 476         found_flex_bg:
 477                 if (flex_size == 1) {
 478                         *group = grp;
 479                         return 0;
 480                 }
 481
 482                 /*
 483                  * We pack inodes at the beginning of the flexgroup's
 484                  * inode tables.  Block allocation decisions will do
 485                  * something similar, although regular files will
 486                  * start at 2nd block group of the flexgroup.  See
 487                  * ext4_ext_find_goal() and ext4_find_near().
 488                  */
 489                 grp *= flex_size;
 490                 for (i = 0; i < flex_size; i++) {
 491                         if (grp+i >= real_ngroups)
 492                                 break;
 493                         desc = ext4_get_group_desc(sb, grp+i, NULL);
 494                         if (desc && ext4_free_inodes_count(sb, desc)) {
 495                                 *group = grp+i;
 496                                 return 0;
 497                         }
 498                 }
 499                 goto fallback;
 500         }
 501
 502         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 503         min_inodes = avefreei - inodes_per_group*flex_size / 4;
 504         if (min_inodes < 1)
 505                 min_inodes = 1;
 506         min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
 507
 508         /*
 509          * Start looking in the flex group where we last allocated an
 510          * inode for this parent directory
 511          */
 512         if (EXT4_I(parent)->i_last_alloc_group != ~0) {
 513                 parent_group = EXT4_I(parent)->i_last_alloc_group;
 514                 if (flex_size > 1)
 515                         parent_group >>= sbi->s_log_groups_per_flex;
 516         }
 517
 518         for (i = 0; i < ngroups; i++) {
 519                 grp = (parent_group + i) % ngroups;
 520                 get_orlov_stats(sb, grp, flex_size, &stats);
 521                 if (stats.used_dirs >= max_dirs)
 522                         continue;
 523                 if (stats.free_inodes < min_inodes)
 524                         continue;
 525                 if (stats.free_clusters < min_clusters)
 526                         continue;
 527                 goto found_flex_bg;
 528         }
 529
 530 fallback:
 531         ngroups = real_ngroups;
 532         avefreei = freei / ngroups;
 533 fallback_retry:
 534         parent_group = EXT4_I(parent)->i_block_group;
 535         for (i = 0; i < ngroups; i++) {
 536                 grp = (parent_group + i) % ngroups;
 537                 desc = ext4_get_group_desc(sb, grp, NULL);
 538                 if (desc) {
 539                         grp_free = ext4_free_inodes_count(sb, desc);
 540                         if (grp_free && grp_free >= avefreei) {
 541                                 *group = grp;
 542                                 return 0;
 543                         }
 544                 }
 545         }
 546
 547         if (avefreei) {
 548                 /*
 549                  * The free-inodes counter is approximate, and for really small
 550                  * filesystems the above test can fail to find any blockgroups
 551                  */
 552                 avefreei = 0;
 553                 goto fallback_retry;
 554         }
 555
 556         return -1;
 557 }
 558
 559 static int find_group_other(struct super_block *sb, struct inode *parent,
 560                             ext4_group_t *group, umode_t mode)
 561 {
 562         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 563         ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
 564         struct ext4_group_desc *desc;
 565         int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
 566
 567         /*
 568          * Try to place the inode is the same flex group as its
 569          * parent.  If we can't find space, use the Orlov algorithm to
 570          * find another flex group, and store that information in the
 571          * parent directory's inode information so that use that flex
 572          * group for future allocations.
 573          */
 574         if (flex_size > 1) {
 575                 int retry = 0;
 576
 577         try_again:
 578                 parent_group &= ~(flex_size-1);
 579                 last = parent_group + flex_size;
 580                 if (last > ngroups)
 581                         last = ngroups;
 582                 for  (i = parent_group; i < last; i++) {
 583                         desc = ext4_get_group_desc(sb, i, NULL);
 584                         if (desc && ext4_free_inodes_count(sb, desc)) {
 585                                 *group = i;
 586                                 return 0;
 587                         }
 588                 }
 589                 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
 590                         retry = 1;
 591                         parent_group = EXT4_I(parent)->i_last_alloc_group;
 592                         goto try_again;
 593                 }
 594                 /*
 595                  * If this didn't work, use the Orlov search algorithm
 596                  * to find a new flex group; we pass in the mode to
 597                  * avoid the topdir algorithms.
 598                  */
 599                 *group = parent_group + flex_size;
 600                 if (*group > ngroups)
 601                         *group = 0;
 602                 return find_group_orlov(sb, parent, group, mode, NULL);
 603         }
 604
 605         /*
 606          * Try to place the inode in its parent directory
 607          */
 608         *group = parent_group;
 609         desc = ext4_get_group_desc(sb, *group, NULL);
 610         if (desc && ext4_free_inodes_count(sb, desc) &&
 611             ext4_free_group_clusters(sb, desc))
 612                 return 0;
 613
 614         /*
 615          * We're going to place this inode in a different blockgroup from its
 616          * parent.  We want to cause files in a common directory to all land in
 617          * the same blockgroup.  But we want files which are in a different
 618          * directory which shares a blockgroup with our parent to land in a
 619          * different blockgroup.
 620          *
 621          * So add our directory's i_ino into the starting point for the hash.
 622          */
 623         *group = (*group + parent->i_ino) % ngroups;
 624
 625         /*
 626          * Use a quadratic hash to find a group with a free inode and some free
 627          * blocks.
 628          */
 629         for (i = 1; i < ngroups; i <<= 1) {
 630                 *group += i;
 631                 if (*group >= ngroups)
 632                         *group -= ngroups;
 633                 desc = ext4_get_group_desc(sb, *group, NULL);
 634                 if (desc && ext4_free_inodes_count(sb, desc) &&
 635                     ext4_free_group_clusters(sb, desc))
 636                         return 0;
 637         }
 638
 639         /*
 640          * That failed: try linear search for a free inode, even if that group
 641          * has no free blocks.
 642          */
 643         *group = parent_group;
 644         for (i = 0; i < ngroups; i++) {
 645                 if (++*group >= ngroups)
 646                         *group = 0;
 647                 desc = ext4_get_group_desc(sb, *group, NULL);
 648                 if (desc && ext4_free_inodes_count(sb, desc))
 649                         return 0;
 650         }
 651
 652         return -1;
 653 }
 654
 655 /*
 656  * In no journal mode, if an inode has recently been deleted, we want
 657  * to avoid reusing it until we're reasonably sure the inode table
 658  * block has been written back to disk.  (Yes, these values are
 659  * somewhat arbitrary...)
 660  */
 661 #define RECENTCY_MIN    5
 662 #define RECENTCY_DIRTY  300
 663
 664 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
 665 {
 666         struct ext4_group_desc  *gdp;
 667         struct ext4_inode       *raw_inode;
 668         struct buffer_head      *bh;
 669         int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
 670         int offset, ret = 0;
 671         int recentcy = RECENTCY_MIN;
 672         u32 dtime, now;
 673
 674         gdp = ext4_get_group_desc(sb, group, NULL);
 675         if (unlikely(!gdp))
 676                 return 0;
 677
 678         bh = sb_find_get_block(sb, ext4_inode_table(sb, gdp) +
 679                        (ino / inodes_per_block));
 680         if (!bh || !buffer_uptodate(bh))
 681                 /*
 682                  * If the block is not in the buffer cache, then it
 683                  * must have been written out.
 684                  */
 685                 goto out;
 686
 687         offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
 688         raw_inode = (struct ext4_inode *) (bh->b_data + offset);
 689
 690         /* i_dtime is only 32 bits on disk, but we only care about relative
 691          * times in the range of a few minutes (i.e. long enough to sync a
 692          * recently-deleted inode to disk), so using the low 32 bits of the
 693          * clock (a 68 year range) is enough, see time_before32() */
 694         dtime = le32_to_cpu(raw_inode->i_dtime);
 695         now = ktime_get_real_seconds();
 696         if (buffer_dirty(bh))
 697                 recentcy += RECENTCY_DIRTY;
 698
 699         if (dtime && time_before32(dtime, now) &&
 700             time_before32(now, dtime + recentcy))
 701                 ret = 1;
 702 out:
 703         brelse(bh);
 704         return ret;
 705 }
 706
 707 static int find_inode_bit(struct super_block *sb, ext4_group_t group,
 708                           struct buffer_head *bitmap, unsigned long *ino)
 709 {
 710 next:
 711         *ino = ext4_find_next_zero_bit((unsigned long *)
 712                                        bitmap->b_data,
 713                                        EXT4_INODES_PER_GROUP(sb), *ino);
 714         if (*ino >= EXT4_INODES_PER_GROUP(sb))
 715                 return 0;
 716
 717         if ((EXT4_SB(sb)->s_journal == NULL) &&
 718             recently_deleted(sb, group, *ino)) {
 719                 *ino = *ino + 1;
 720                 if (*ino < EXT4_INODES_PER_GROUP(sb))
 721                         goto next;
 722                 return 0;
 723         }
 724
 725         return 1;
 726 }
 727
 728 /*
 729  * There are two policies for allocating an inode.  If the new inode is
 730  * a directory, then a forward search is made for a block group with both
 731  * free space and a low directory-to-inode ratio; if that fails, then of
 732  * the groups with above-average free space, that group with the fewest
 733  * directories already is chosen.
 734  *
 735  * For other inodes, search forward from the parent directory's block
 736  * group to find a free inode.
 737  */
 738 struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 739                                umode_t mode, const struct qstr *qstr,
 740                                __u32 goal, uid_t *owner, __u32 i_flags,
 741                                int handle_type, unsigned int line_no,
 742                                int nblocks)
 743 {
 744         struct super_block *sb;
 745         struct buffer_head *inode_bitmap_bh = NULL;
 746         struct buffer_head *group_desc_bh;
 747         ext4_group_t ngroups, group = 0;
 748         unsigned long ino = 0;
 749         struct inode *inode;
 750         struct ext4_group_desc *gdp = NULL;
 751         struct ext4_inode_info *ei;
 752         struct ext4_sb_info *sbi;
 753         int ret2, err;
 754         struct inode *ret;
 755         ext4_group_t i;
 756         ext4_group_t flex_group;
 757         struct ext4_group_info *grp;
 758         int encrypt = 0;
 759
 760         /* Cannot create files in a deleted directory */
 761         if (!dir || !dir->i_nlink)
 762                 return ERR_PTR(-EPERM);
 763
 764         sb = dir->i_sb;
 765         sbi = EXT4_SB(sb);
 766
 767         if (unlikely(ext4_forced_shutdown(sbi)))
 768                 return ERR_PTR(-EIO);
 769
 770         if ((ext4_encrypted_inode(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) &&
 771             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) &&
 772             !(i_flags & EXT4_EA_INODE_FL)) {
 773                 err = fscrypt_get_encryption_info(dir);
 774                 if (err)
 775                         return ERR_PTR(err);
 776                 if (!fscrypt_has_encryption_key(dir))
 777                         return ERR_PTR(-ENOKEY);
 778                 encrypt = 1;
 779         }
 780
 781         if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
 782 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 783                 struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
 784
 785                 if (IS_ERR(p))
 786                         return ERR_CAST(p);
 787                 if (p) {
 788                         int acl_size = p->a_count * sizeof(ext4_acl_entry);
 789
 790                         nblocks += (S_ISDIR(mode) ? 2 : 1) *
 791                                 __ext4_xattr_set_credits(sb, NULL /* inode */,
 792                                         NULL /* block_bh */, acl_size,
 793                                         true /* is_create */);
 794                         posix_acl_release(p);
 795                 }
 796 #endif
 797
 798 #ifdef CONFIG_SECURITY
 799                 {
 800                         int num_security_xattrs = 1;
 801
 802 #ifdef CONFIG_INTEGRITY
 803                         num_security_xattrs++;
 804 #endif
 805                         /*
 806                          * We assume that security xattrs are never
 807                          * more than 1k.  In practice they are under
 808                          * 128 bytes.
 809                          */
 810                         nblocks += num_security_xattrs *
 811                                 __ext4_xattr_set_credits(sb, NULL /* inode */,
 812                                         NULL /* block_bh */, 1024,
 813                                         true /* is_create */);
 814                 }
 815 #endif
 816                 if (encrypt)
 817                         nblocks += __ext4_xattr_set_credits(sb,
 818                                         NULL /* inode */, NULL /* block_bh */,
 819                                         FSCRYPT_SET_CONTEXT_MAX_SIZE,
 820                                         true /* is_create */);
 821         }
 822
 823         ngroups = ext4_get_groups_count(sb);
 824         trace_ext4_request_inode(dir, mode);
 825         inode = new_inode(sb);
 826         if (!inode)
 827                 return ERR_PTR(-ENOMEM);
 828         ei = EXT4_I(inode);
 829
 830         /*
 831          * Initialize owners and quota early so that we don't have to account
 832          * for quota initialization worst case in standard inode creating
 833          * transaction
 834          */
 835         if (owner) {
 836                 inode->i_mode = mode;
 837                 i_uid_write(inode, owner[0]);
 838                 i_gid_write(inode, owner[1]);
 839         } else if (test_opt(sb, GRPID)) {
 840                 inode->i_mode = mode;
 841                 inode->i_uid = current_fsuid();
 842                 inode->i_gid = dir->i_gid;
 843         } else
 844                 inode_init_owner(inode, dir, mode);
 845
 846         if (ext4_has_feature_project(sb) &&
 847             ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
 848                 ei->i_projid = EXT4_I(dir)->i_projid;
 849         else
 850                 ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
 851
 852         err = dquot_initialize(inode);
 853         if (err)
 854                 goto out;
 855
 856         if (!goal)
 857                 goal = sbi->s_inode_goal;
 858
 859         if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
 860                 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
 861                 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
 862                 ret2 = 0;
 863                 goto got_group;
 864         }
 865
 866         if (S_ISDIR(mode))
 867                 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
 868         else
 869                 ret2 = find_group_other(sb, dir, &group, mode);
 870
 871 got_group:
 872         EXT4_I(dir)->i_last_alloc_group = group;
 873         err = -ENOSPC;
 874         if (ret2 == -1)
 875                 goto out;
 876
 877         /*
 878          * Normally we will only go through one pass of this loop,
 879          * unless we get unlucky and it turns out the group we selected
 880          * had its last inode grabbed by someone else.
 881          */
 882         for (i = 0; i < ngroups; i++, ino = 0) {
 883                 err = -EIO;
 884
 885                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 886                 if (!gdp)
 887                         goto out;
 888
 889                 /*
 890                  * Check free inodes count before loading bitmap.
 891                  */
 892                 if (ext4_free_inodes_count(sb, gdp) == 0)
 893                         goto next_group;
 894
 895                 grp = ext4_get_group_info(sb, group);
 896                 /* Skip groups with already-known suspicious inode tables */
 897                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
 898                         goto next_group;
 899
 900                 brelse(inode_bitmap_bh);
 901                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 902                 /* Skip groups with suspicious inode tables */
 903                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
 904                     IS_ERR(inode_bitmap_bh)) {
 905                         inode_bitmap_bh = NULL;
 906                         goto next_group;
 907                 }
 908
 909 repeat_in_this_group:
 910                 ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
 911                 if (!ret2)
 912                         goto next_group;
 913
 914                 if (group == 0 && (ino + 1) < EXT4_FIRST_INO(sb)) {
 915                         ext4_error(sb, "reserved inode found cleared - "
 916                                    "inode=%lu", ino + 1);
 917                         goto next_group;
 918                 }
 919
 920                 if (!handle) {
 921                         BUG_ON(nblocks <= 0);
 922                         handle = __ext4_journal_start_sb(dir->i_sb, line_no,
 923                                                          handle_type, nblocks,
 924                                                          0);
 925                         if (IS_ERR(handle)) {
 926                                 err = PTR_ERR(handle);
 927                                 ext4_std_error(sb, err);
 928                                 goto out;
 929                         }
 930                 }
 931                 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 932                 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
 933                 if (err) {
 934                         ext4_std_error(sb, err);
 935                         goto out;
 936                 }
 937                 ext4_lock_group(sb, group);
 938                 ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
 939                 if (ret2) {
 940                         /* Someone already took the bit. Repeat the search
 941                          * with lock held.
 942                          */
 943                         ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
 944                         if (ret2) {
 945                                 ext4_set_bit(ino, inode_bitmap_bh->b_data);
 946                                 ret2 = 0;
 947                         } else {
 948                                 ret2 = 1; /* we didn't grab the inode */
 949                         }
 950                 }
 951                 ext4_unlock_group(sb, group);
 952                 ino++;          /* the inode bitmap is zero-based */
 953                 if (!ret2)
 954                         goto got; /* we grabbed the inode! */
 955
 956                 if (ino < EXT4_INODES_PER_GROUP(sb))
 957                         goto repeat_in_this_group;
 958 next_group:
 959                 if (++group == ngroups)
 960                         group = 0;
 961         }
 962         err = -ENOSPC;
 963         goto out;
 964
 965 got:
 966         BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
 967         err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
 968         if (err) {
 969                 ext4_std_error(sb, err);
 970                 goto out;
 971         }
 972
 973         BUFFER_TRACE(group_desc_bh, "get_write_access");
 974         err = ext4_journal_get_write_access(handle, group_desc_bh);
 975         if (err) {
 976                 ext4_std_error(sb, err);
 977                 goto out;
 978         }
 979
 980         /* We may have to initialize the block bitmap if it isn't already */
 981         if (ext4_has_group_desc_csum(sb) &&
 982             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 983                 struct buffer_head *block_bitmap_bh;
 984
 985                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 986                 if (IS_ERR(block_bitmap_bh)) {
 987                         err = PTR_ERR(block_bitmap_bh);
 988                         goto out;
 989                 }
 990                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 991                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 992                 if (err) {
 993                         brelse(block_bitmap_bh);
 994                         ext4_std_error(sb, err);
 995                         goto out;
 996                 }
 997
 998                 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
 999                 err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
1000
1001                 /* recheck and clear flag under lock if we still need to */
1002                 ext4_lock_group(sb, group);
1003                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
1004                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
1005                         ext4_free_group_clusters_set(sb, gdp,
1006                                 ext4_free_clusters_after_init(sb, group, gdp));
1007                         ext4_block_bitmap_csum_set(sb, group, gdp,
1008                                                    block_bitmap_bh);
1009                         ext4_group_desc_csum_set(sb, group, gdp);
1010                 }
1011                 ext4_unlock_group(sb, group);
1012                 brelse(block_bitmap_bh);
1013
1014                 if (err) {
1015                         ext4_std_error(sb, err);
1016                         goto out;
1017                 }
1018         }
1019
1020         /* Update the relevant bg descriptor fields */
1021         if (ext4_has_group_desc_csum(sb)) {
1022                 int free;
1023                 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1024
1025                 down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
1026                 ext4_lock_group(sb, group); /* while we modify the bg desc */
1027                 free = EXT4_INODES_PER_GROUP(sb) -
1028                         ext4_itable_unused_count(sb, gdp);
1029                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
1030                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
1031                         free = 0;
1032                 }
1033                 /*
1034                  * Check the relative inode number against the last used
1035                  * relative inode number in this group. if it is greater
1036                  * we need to update the bg_itable_unused count
1037                  */
1038                 if (ino > free)
1039                         ext4_itable_unused_set(sb, gdp,
1040                                         (EXT4_INODES_PER_GROUP(sb) - ino));
1041                 up_read(&grp->alloc_sem);
1042         } else {
1043                 ext4_lock_group(sb, group);
1044         }
1045
1046         ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1047         if (S_ISDIR(mode)) {
1048                 ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1049                 if (sbi->s_log_groups_per_flex) {
1050                         ext4_group_t f = ext4_flex_group(sbi, group);
1051
1052                         atomic_inc(&sbi->s_flex_groups[f].used_dirs);
1053                 }
1054         }
1055         if (ext4_has_group_desc_csum(sb)) {
1056                 ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1057                                            EXT4_INODES_PER_GROUP(sb) / 8);
1058                 ext4_group_desc_csum_set(sb, group, gdp);
1059         }
1060         ext4_unlock_group(sb, group);
1061
1062         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1063         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1064         if (err) {
1065                 ext4_std_error(sb, err);
1066                 goto out;
1067         }
1068
1069         percpu_counter_dec(&sbi->s_freeinodes_counter);
1070         if (S_ISDIR(mode))
1071                 percpu_counter_inc(&sbi->s_dirs_counter);
1072
1073         if (sbi->s_log_groups_per_flex) {
1074                 flex_group = ext4_flex_group(sbi, group);
1075                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
1076         }
1077
1078         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1079         /* This is the optimal IO size (for stat), not the fs block size */
1080         inode->i_blocks = 0;
1081         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
1082                                                        current_time(inode);
1083
1084         memset(ei->i_data, 0, sizeof(ei->i_data));
1085         ei->i_dir_start_lookup = 0;
1086         ei->i_disksize = 0;
1087
1088         /* Don't inherit extent flag from directory, amongst others. */
1089         ei->i_flags =
1090                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1091         ei->i_flags |= i_flags;
1092         ei->i_file_acl = 0;
1093         ei->i_dtime = 0;
1094         ei->i_block_group = group;
1095         ei->i_last_alloc_group = ~0;
1096
1097         ext4_set_inode_flags(inode);
1098         if (IS_DIRSYNC(inode))
1099                 ext4_handle_sync(handle);
1100         if (insert_inode_locked(inode) < 0) {
1101                 /*
1102                  * Likely a bitmap corruption causing inode to be allocated
1103                  * twice.
1104                  */
1105                 err = -EIO;
1106                 ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1107                            inode->i_ino);
1108                 goto out;
1109         }
1110         inode->i_generation = prandom_u32();
1111
1112         /* Precompute checksum seed for inode metadata */
1113         if (ext4_has_metadata_csum(sb)) {
1114                 __u32 csum;
1115                 __le32 inum = cpu_to_le32(inode->i_ino);
1116                 __le32 gen = cpu_to_le32(inode->i_generation);
1117                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1118                                    sizeof(inum));
1119                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1120                                               sizeof(gen));
1121         }
1122
1123         ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1124         ext4_set_inode_state(inode, EXT4_STATE_NEW);
1125
1126         ei->i_extra_isize = sbi->s_want_extra_isize;
1127         ei->i_inline_off = 0;
1128         if (ext4_has_feature_inline_data(sb))
1129                 ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1130         ret = inode;
1131         err = dquot_alloc_inode(inode);
1132         if (err)
1133                 goto fail_drop;
1134
1135         /*
1136          * Since the encryption xattr will always be unique, create it first so
1137          * that it's less likely to end up in an external xattr block and
1138          * prevent its deduplication.
1139          */
1140         if (encrypt) {
1141                 err = fscrypt_inherit_context(dir, inode, handle, true);
1142                 if (err)
1143                         goto fail_free_drop;
1144         }
1145
1146         if (!(ei->i_flags & EXT4_EA_INODE_FL)) {
1147                 err = ext4_init_acl(handle, inode, dir);
1148                 if (err)
1149                         goto fail_free_drop;
1150
1151                 err = ext4_init_security(handle, inode, dir, qstr);
1152                 if (err)
1153                         goto fail_free_drop;
1154         }
1155
1156         if (ext4_has_feature_extents(sb)) {
1157                 /* set extent flag only for directory, file and normal symlink*/
1158                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1159                         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1160                         ext4_ext_tree_init(handle, inode);
1161                 }
1162         }
1163
1164         if (ext4_handle_valid(handle)) {
1165                 ei->i_sync_tid = handle->h_transaction->t_tid;
1166                 ei->i_datasync_tid = handle->h_transaction->t_tid;
1167         }
1168
1169         err = ext4_mark_inode_dirty(handle, inode);
1170         if (err) {
1171                 ext4_std_error(sb, err);
1172                 goto fail_free_drop;
1173         }
1174
1175         ext4_debug("allocating inode %lu\n", inode->i_ino);
1176         trace_ext4_allocate_inode(inode, dir, mode);
1177         brelse(inode_bitmap_bh);
1178         return ret;
1179
1180 fail_free_drop:
1181         dquot_free_inode(inode);
1182 fail_drop:
1183         clear_nlink(inode);
1184         unlock_new_inode(inode);
1185 out:
1186         dquot_drop(inode);
1187         inode->i_flags |= S_NOQUOTA;
1188         iput(inode);
1189         brelse(inode_bitmap_bh);
1190         return ERR_PTR(err);
1191 }
1192
1193 /* Verify that we are loading a valid orphan from disk */
1194 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1195 {
1196         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1197         ext4_group_t block_group;
1198         int bit;
1199         struct buffer_head *bitmap_bh = NULL;
1200         struct inode *inode = NULL;
1201         int err = -EFSCORRUPTED;
1202
1203         if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
1204                 goto bad_orphan;
1205
1206         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1207         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1208         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1209         if (IS_ERR(bitmap_bh)) {
1210                 ext4_error(sb, "inode bitmap error %ld for orphan %lu",
1211                            ino, PTR_ERR(bitmap_bh));
1212                 return (struct inode *) bitmap_bh;
1213         }
1214
1215         /* Having the inode bit set should be a 100% indicator that this
1216          * is a valid orphan (no e2fsck run on fs).  Orphans also include
1217          * inodes that were being truncated, so we can't check i_nlink==0.
1218          */
1219         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1220                 goto bad_orphan;
1221
1222         inode = ext4_iget(sb, ino);
1223         if (IS_ERR(inode)) {
1224                 err = PTR_ERR(inode);
1225                 ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
1226                            ino, err);
1227                 return inode;
1228         }
1229
1230         /*
1231          * If the orphans has i_nlinks > 0 then it should be able to
1232          * be truncated, otherwise it won't be removed from the orphan
1233          * list during processing and an infinite loop will result.
1234          * Similarly, it must not be a bad inode.
1235          */
1236         if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
1237             is_bad_inode(inode))
1238                 goto bad_orphan;
1239
1240         if (NEXT_ORPHAN(inode) > max_ino)
1241                 goto bad_orphan;
1242         brelse(bitmap_bh);
1243         return inode;
1244
1245 bad_orphan:
1246         ext4_error(sb, "bad orphan inode %lu", ino);
1247         if (bitmap_bh)
1248                 printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1249                        bit, (unsigned long long)bitmap_bh->b_blocknr,
1250                        ext4_test_bit(bit, bitmap_bh->b_data));
1251         if (inode) {
1252                 printk(KERN_ERR "is_bad_inode(inode)=%d\n",
1253                        is_bad_inode(inode));
1254                 printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
1255                        NEXT_ORPHAN(inode));
1256                 printk(KERN_ERR "max_ino=%lu\n", max_ino);
1257                 printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
1258                 /* Avoid freeing blocks if we got a bad deleted inode */
1259                 if (inode->i_nlink == 0)
1260                         inode->i_blocks = 0;
1261                 iput(inode);
1262         }
1263         brelse(bitmap_bh);
1264         return ERR_PTR(err);
1265 }
1266
1267 unsigned long ext4_count_free_inodes(struct super_block *sb)
1268 {
1269         unsigned long desc_count;
1270         struct ext4_group_desc *gdp;
1271         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1272 #ifdef EXT4FS_DEBUG
1273         struct ext4_super_block *es;
1274         unsigned long bitmap_count, x;
1275         struct buffer_head *bitmap_bh = NULL;
1276
1277         es = EXT4_SB(sb)->s_es;
1278         desc_count = 0;
1279         bitmap_count = 0;
1280         gdp = NULL;
1281         for (i = 0; i < ngroups; i++) {
1282                 gdp = ext4_get_group_desc(sb, i, NULL);
1283                 if (!gdp)
1284                         continue;
1285                 desc_count += ext4_free_inodes_count(sb, gdp);
1286                 brelse(bitmap_bh);
1287                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1288                 if (IS_ERR(bitmap_bh)) {
1289                         bitmap_bh = NULL;
1290                         continue;
1291                 }
1292
1293                 x = ext4_count_free(bitmap_bh->b_data,
1294                                     EXT4_INODES_PER_GROUP(sb) / 8);
1295                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1296                         (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1297                 bitmap_count += x;
1298         }
1299         brelse(bitmap_bh);
1300         printk(KERN_DEBUG "ext4_count_free_inodes: "
1301                "stored = %u, computed = %lu, %lu\n",
1302                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1303         return desc_count;
1304 #else
1305         desc_count = 0;
1306         for (i = 0; i < ngroups; i++) {
1307                 gdp = ext4_get_group_desc(sb, i, NULL);
1308                 if (!gdp)
1309                         continue;
1310                 desc_count += ext4_free_inodes_count(sb, gdp);
1311                 cond_resched();
1312         }
1313         return desc_count;
1314 #endif
1315 }
1316
1317 /* Called at mount-time, super-block is locked */
1318 unsigned long ext4_count_dirs(struct super_block * sb)
1319 {
1320         unsigned long count = 0;
1321         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1322
1323         for (i = 0; i < ngroups; i++) {
1324                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1325                 if (!gdp)
1326                         continue;
1327                 count += ext4_used_dirs_count(sb, gdp);
1328         }
1329         return count;
1330 }
1331
1332 /*
1333  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1334  * inode table. Must be called without any spinlock held. The only place
1335  * where it is called from on active part of filesystem is ext4lazyinit
1336  * thread, so we do not need any special locks, however we have to prevent
1337  * inode allocation from the current group, so we take alloc_sem lock, to
1338  * block ext4_new_inode() until we are finished.
1339  */
1340 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1341                                  int barrier)
1342 {
1343         struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1344         struct ext4_sb_info *sbi = EXT4_SB(sb);
1345         struct ext4_group_desc *gdp = NULL;
1346         struct buffer_head *group_desc_bh;
1347         handle_t *handle;
1348         ext4_fsblk_t blk;
1349         int num, ret = 0, used_blks = 0;
1350
1351         /* This should not happen, but just to be sure check this */
1352         if (sb_rdonly(sb)) {
1353                 ret = 1;
1354                 goto out;
1355         }
1356
1357         gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1358         if (!gdp)
1359                 goto out;
1360
1361         /*
1362          * We do not need to lock this, because we are the only one
1363          * handling this flag.
1364          */
1365         if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1366                 goto out;
1367
1368         handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1369         if (IS_ERR(handle)) {
1370                 ret = PTR_ERR(handle);
1371                 goto out;
1372         }
1373
1374         down_write(&grp->alloc_sem);
1375         /*
1376          * If inode bitmap was already initialized there may be some
1377          * used inodes so we need to skip blocks with used inodes in
1378          * inode table.
1379          */
1380         if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1381                 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1382                             ext4_itable_unused_count(sb, gdp)),
1383                             sbi->s_inodes_per_block);
1384
1385         if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1386                 ext4_error(sb, "Something is wrong with group %u: "
1387                            "used itable blocks: %d; "
1388                            "itable unused count: %u",
1389                            group, used_blks,
1390                            ext4_itable_unused_count(sb, gdp));
1391                 ret = 1;
1392                 goto err_out;
1393         }
1394
1395         blk = ext4_inode_table(sb, gdp) + used_blks;
1396         num = sbi->s_itb_per_group - used_blks;
1397
1398         BUFFER_TRACE(group_desc_bh, "get_write_access");
1399         ret = ext4_journal_get_write_access(handle,
1400                                             group_desc_bh);
1401         if (ret)
1402                 goto err_out;
1403
1404         /*
1405          * Skip zeroout if the inode table is full. But we set the ZEROED
1406          * flag anyway, because obviously, when it is full it does not need
1407          * further zeroing.
1408          */
1409         if (unlikely(num == 0))
1410                 goto skip_zeroout;
1411
1412         ext4_debug("going to zero out inode table in group %d\n",
1413                    group);
1414         ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1415         if (ret < 0)
1416                 goto err_out;
1417         if (barrier)
1418                 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1419
1420 skip_zeroout:
1421         ext4_lock_group(sb, group);
1422         gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1423         ext4_group_desc_csum_set(sb, group, gdp);
1424         ext4_unlock_group(sb, group);
1425
1426         BUFFER_TRACE(group_desc_bh,
1427                      "call ext4_handle_dirty_metadata");
1428         ret = ext4_handle_dirty_metadata(handle, NULL,
1429                                          group_desc_bh);
1430
1431 err_out:
1432         up_write(&grp->alloc_sem);
1433         ext4_journal_stop(handle);
1434 out:
1435         return ret;
1436 }