fs/ext4/ialloc.c

   1 /*
   2  *  linux/fs/ext4/ialloc.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  BSD ufs-inspired inode and directory allocation by
  10  *  Stephen Tweedie (sct@redhat.com), 1993
  11  *  Big-endian to little-endian byte-swapping/bitmaps by
  12  *        David S. Miller (davem@caip.rutgers.edu), 1995
  13  */
  14
  15 #include <linux/time.h>
  16 #include <linux/fs.h>
  17 #include <linux/jbd2.h>
  18 #include <linux/stat.h>
  19 #include <linux/string.h>
  20 #include <linux/quotaops.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/random.h>
  23 #include <linux/bitops.h>
  24 #include <linux/blkdev.h>
  25 #include <asm/byteorder.h>
  26
  27 #include "ext4.h"
  28 #include "ext4_jbd2.h"
  29 #include "xattr.h"
  30 #include "acl.h"
  31
  32 #include <trace/events/ext4.h>
  33
  34 /*
  35  * ialloc.c contains the inodes allocation and deallocation routines
  36  */
  37
  38 /*
  39  * The free inodes are managed by bitmaps.  A file system contains several
  40  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  41  * block for inodes, N blocks for the inode table and data blocks.
  42  *
  43  * The file system contains group descriptors which are located after the
  44  * super block.  Each descriptor contains the number of the bitmap block and
  45  * the free blocks count in the block.
  46  */
  47
  48 /*
  49  * To avoid calling the atomic setbit hundreds or thousands of times, we only
  50  * need to use it within a single byte (to ensure we get endianness right).
  51  * We can use memset for the rest of the bitmap as there are no other users.
  52  */
  53 void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
  54 {
  55         int i;
  56
  57         if (start_bit >= end_bit)
  58                 return;
  59
  60         ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
  61         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
  62                 ext4_set_bit(i, bitmap);
  63         if (i < end_bit)
  64                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
  65 }
  66
  67 /* Initializes an uninitialized inode bitmap */
  68 unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh,
  69                                 ext4_group_t block_group,
  70                                 struct ext4_group_desc *gdp)
  71 {
  72         struct ext4_sb_info *sbi = EXT4_SB(sb);
  73
  74         J_ASSERT_BH(bh, buffer_locked(bh));
  75
  76         /* If checksum is bad mark all blocks and inodes use to prevent
  77          * allocation, essentially implementing a per-group read-only flag. */
  78         if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
  79                 ext4_error(sb, "Checksum bad for group %u", block_group);
  80                 ext4_free_blks_set(sb, gdp, 0);
  81                 ext4_free_inodes_set(sb, gdp, 0);
  82                 ext4_itable_unused_set(sb, gdp, 0);
  83                 memset(bh->b_data, 0xff, sb->s_blocksize);
  84                 return 0;
  85         }
  86
  87         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
  88         mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
  89                         bh->b_data);
  90
  91         return EXT4_INODES_PER_GROUP(sb);
  92 }
  93
  94 /*
  95  * Read the inode allocation bitmap for a given block_group, reading
  96  * into the specified slot in the superblock's bitmap cache.
  97  *
  98  * Return buffer_head of bitmap on success or NULL.
  99  */
 100 static struct buffer_head *
 101 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 102 {
 103         struct ext4_group_desc *desc;
 104         struct buffer_head *bh = NULL;
 105         ext4_fsblk_t bitmap_blk;
 106
 107         desc = ext4_get_group_desc(sb, block_group, NULL);
 108         if (!desc)
 109                 return NULL;
 110         bitmap_blk = ext4_inode_bitmap(sb, desc);
 111         bh = sb_getblk(sb, bitmap_blk);
 112         if (unlikely(!bh)) {
 113                 ext4_error(sb, "Cannot read inode bitmap - "
 114                             "block_group = %u, inode_bitmap = %llu",
 115                             block_group, bitmap_blk);
 116                 return NULL;
 117         }
 118         if (bitmap_uptodate(bh))
 119                 return bh;
 120
 121         lock_buffer(bh);
 122         if (bitmap_uptodate(bh)) {
 123                 unlock_buffer(bh);
 124                 return bh;
 125         }
 126         ext4_lock_group(sb, block_group);
 127         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 128                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
 129                 set_bitmap_uptodate(bh);
 130                 set_buffer_uptodate(bh);
 131                 ext4_unlock_group(sb, block_group);
 132                 unlock_buffer(bh);
 133                 return bh;
 134         }
 135         ext4_unlock_group(sb, block_group);
 136         if (buffer_uptodate(bh)) {
 137                 /*
 138                  * if not uninit if bh is uptodate,
 139                  * bitmap is also uptodate
 140                  */
 141                 set_bitmap_uptodate(bh);
 142                 unlock_buffer(bh);
 143                 return bh;
 144         }
 145         /*
 146          * submit the buffer_head for read. We can
 147          * safely mark the bitmap as uptodate now.
 148          * We do it here so the bitmap uptodate bit
 149          * get set with buffer lock held.
 150          */
 151         set_bitmap_uptodate(bh);
 152         if (bh_submit_read(bh) < 0) {
 153                 put_bh(bh);
 154                 ext4_error(sb, "Cannot read inode bitmap - "
 155                             "block_group = %u, inode_bitmap = %llu",
 156                             block_group, bitmap_blk);
 157                 return NULL;
 158         }
 159         return bh;
 160 }
 161
 162 /*
 163  * NOTE! When we get the inode, we're the only people
 164  * that have access to it, and as such there are no
 165  * race conditions we have to worry about. The inode
 166  * is not on the hash-lists, and it cannot be reached
 167  * through the filesystem because the directory entry
 168  * has been deleted earlier.
 169  *
 170  * HOWEVER: we must make sure that we get no aliases,
 171  * which means that we have to call "clear_inode()"
 172  * _before_ we mark the inode not in use in the inode
 173  * bitmaps. Otherwise a newly created file might use
 174  * the same inode number (not actually the same pointer
 175  * though), and then we'd have two inodes sharing the
 176  * same inode number and space on the harddisk.
 177  */
 178 void ext4_free_inode(handle_t *handle, struct inode *inode)
 179 {
 180         struct super_block *sb = inode->i_sb;
 181         int is_directory;
 182         unsigned long ino;
 183         struct buffer_head *bitmap_bh = NULL;
 184         struct buffer_head *bh2;
 185         ext4_group_t block_group;
 186         unsigned long bit;
 187         struct ext4_group_desc *gdp;
 188         struct ext4_super_block *es;
 189         struct ext4_sb_info *sbi;
 190         int fatal = 0, err, count, cleared;
 191
 192         if (atomic_read(&inode->i_count) > 1) {
 193                 printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
 194                        atomic_read(&inode->i_count));
 195                 return;
 196         }
 197         if (inode->i_nlink) {
 198                 printk(KERN_ERR "ext4_free_inode: inode has nlink=%d\n",
 199                        inode->i_nlink);
 200                 return;
 201         }
 202         if (!sb) {
 203                 printk(KERN_ERR "ext4_free_inode: inode on "
 204                        "nonexistent device\n");
 205                 return;
 206         }
 207         sbi = EXT4_SB(sb);
 208
 209         ino = inode->i_ino;
 210         ext4_debug("freeing inode %lu\n", ino);
 211         trace_ext4_free_inode(inode);
 212
 213         /*
 214          * Note: we must free any quota before locking the superblock,
 215          * as writing the quota to disk may need the lock as well.
 216          */
 217         dquot_initialize(inode);
 218         ext4_xattr_delete_inode(handle, inode);
 219         dquot_free_inode(inode);
 220         dquot_drop(inode);
 221
 222         is_directory = S_ISDIR(inode->i_mode);
 223
 224         /* Do this BEFORE marking the inode not in use or returning an error */
 225         ext4_clear_inode(inode);
 226
 227         es = EXT4_SB(sb)->s_es;
 228         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 229                 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
 230                 goto error_return;
 231         }
 232         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 233         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 234         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 235         if (!bitmap_bh)
 236                 goto error_return;
 237
 238         BUFFER_TRACE(bitmap_bh, "get_write_access");
 239         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 240         if (fatal)
 241                 goto error_return;
 242
 243         fatal = -ESRCH;
 244         gdp = ext4_get_group_desc(sb, block_group, &bh2);
 245         if (gdp) {
 246                 BUFFER_TRACE(bh2, "get_write_access");
 247                 fatal = ext4_journal_get_write_access(handle, bh2);
 248         }
 249         ext4_lock_group(sb, block_group);
 250         cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
 251         if (fatal || !cleared) {
 252                 ext4_unlock_group(sb, block_group);
 253                 goto out;
 254         }
 255
 256         count = ext4_free_inodes_count(sb, gdp) + 1;
 257         ext4_free_inodes_set(sb, gdp, count);
 258         if (is_directory) {
 259                 count = ext4_used_dirs_count(sb, gdp) - 1;
 260                 ext4_used_dirs_set(sb, gdp, count);
 261                 percpu_counter_dec(&sbi->s_dirs_counter);
 262         }
 263         gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
 264         ext4_unlock_group(sb, block_group);
 265
 266         percpu_counter_inc(&sbi->s_freeinodes_counter);
 267         if (sbi->s_log_groups_per_flex) {
 268                 ext4_group_t f = ext4_flex_group(sbi, block_group);
 269
 270                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 271                 if (is_directory)
 272                         atomic_dec(&sbi->s_flex_groups[f].used_dirs);
 273         }
 274         BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 275         fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
 276 out:
 277         if (cleared) {
 278                 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 279                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 280                 if (!fatal)
 281                         fatal = err;
 282                 ext4_mark_super_dirty(sb);
 283         } else
 284                 ext4_error(sb, "bit already cleared for inode %lu", ino);
 285
 286 error_return:
 287         brelse(bitmap_bh);
 288         ext4_std_error(sb, fatal);
 289 }
 290
 291 /*
 292  * There are two policies for allocating an inode.  If the new inode is
 293  * a directory, then a forward search is made for a block group with both
 294  * free space and a low directory-to-inode ratio; if that fails, then of
 295  * the groups with above-average free space, that group with the fewest
 296  * directories already is chosen.
 297  *
 298  * For other inodes, search forward from the parent directory\'s block
 299  * group to find a free inode.
 300  */
 301 static int find_group_dir(struct super_block *sb, struct inode *parent,
 302                                 ext4_group_t *best_group)
 303 {
 304         ext4_group_t ngroups = ext4_get_groups_count(sb);
 305         unsigned int freei, avefreei;
 306         struct ext4_group_desc *desc, *best_desc = NULL;
 307         ext4_group_t group;
 308         int ret = -1;
 309
 310         freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
 311         avefreei = freei / ngroups;
 312
 313         for (group = 0; group < ngroups; group++) {
 314                 desc = ext4_get_group_desc(sb, group, NULL);
 315                 if (!desc || !ext4_free_inodes_count(sb, desc))
 316                         continue;
 317                 if (ext4_free_inodes_count(sb, desc) < avefreei)
 318                         continue;
 319                 if (!best_desc ||
 320                     (ext4_free_blks_count(sb, desc) >
 321                      ext4_free_blks_count(sb, best_desc))) {
 322                         *best_group = group;
 323                         best_desc = desc;
 324                         ret = 0;
 325                 }
 326         }
 327         return ret;
 328 }
 329
 330 #define free_block_ratio 10
 331
 332 static int find_group_flex(struct super_block *sb, struct inode *parent,
 333                            ext4_group_t *best_group)
 334 {
 335         struct ext4_sb_info *sbi = EXT4_SB(sb);
 336         struct ext4_group_desc *desc;
 337         struct flex_groups *flex_group = sbi->s_flex_groups;
 338         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 339         ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
 340         ext4_group_t ngroups = ext4_get_groups_count(sb);
 341         int flex_size = ext4_flex_bg_size(sbi);
 342         ext4_group_t best_flex = parent_fbg_group;
 343         int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
 344         int flexbg_free_blocks;
 345         int flex_freeb_ratio;
 346         ext4_group_t n_fbg_groups;
 347         ext4_group_t i;
 348
 349         n_fbg_groups = (ngroups + flex_size - 1) >>
 350                 sbi->s_log_groups_per_flex;
 351
 352 find_close_to_parent:
 353         flexbg_free_blocks = atomic_read(&flex_group[best_flex].free_blocks);
 354         flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 355         if (atomic_read(&flex_group[best_flex].free_inodes) &&
 356             flex_freeb_ratio > free_block_ratio)
 357                 goto found_flexbg;
 358
 359         if (best_flex && best_flex == parent_fbg_group) {
 360                 best_flex--;
 361                 goto find_close_to_parent;
 362         }
 363
 364         for (i = 0; i < n_fbg_groups; i++) {
 365                 if (i == parent_fbg_group || i == parent_fbg_group - 1)
 366                         continue;
 367
 368                 flexbg_free_blocks = atomic_read(&flex_group[i].free_blocks);
 369                 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 370
 371                 if (flex_freeb_ratio > free_block_ratio &&
 372                     (atomic_read(&flex_group[i].free_inodes))) {
 373                         best_flex = i;
 374                         goto found_flexbg;
 375                 }
 376
 377                 if ((atomic_read(&flex_group[best_flex].free_inodes) == 0) ||
 378                     ((atomic_read(&flex_group[i].free_blocks) >
 379                       atomic_read(&flex_group[best_flex].free_blocks)) &&
 380                      atomic_read(&flex_group[i].free_inodes)))
 381                         best_flex = i;
 382         }
 383
 384         if (!atomic_read(&flex_group[best_flex].free_inodes) ||
 385             !atomic_read(&flex_group[best_flex].free_blocks))
 386                 return -1;
 387
 388 found_flexbg:
 389         for (i = best_flex * flex_size; i < ngroups &&
 390                      i < (best_flex + 1) * flex_size; i++) {
 391                 desc = ext4_get_group_desc(sb, i, NULL);
 392                 if (ext4_free_inodes_count(sb, desc)) {
 393                         *best_group = i;
 394                         goto out;
 395                 }
 396         }
 397
 398         return -1;
 399 out:
 400         return 0;
 401 }
 402
 403 struct orlov_stats {
 404         __u32 free_inodes;
 405         __u32 free_blocks;
 406         __u32 used_dirs;
 407 };
 408
 409 /*
 410  * Helper function for Orlov's allocator; returns critical information
 411  * for a particular block group or flex_bg.  If flex_size is 1, then g
 412  * is a block group number; otherwise it is flex_bg number.
 413  */
 414 void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 415                        int flex_size, struct orlov_stats *stats)
 416 {
 417         struct ext4_group_desc *desc;
 418         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
 419
 420         if (flex_size > 1) {
 421                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
 422                 stats->free_blocks = atomic_read(&flex_group[g].free_blocks);
 423                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
 424                 return;
 425         }
 426
 427         desc = ext4_get_group_desc(sb, g, NULL);
 428         if (desc) {
 429                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
 430                 stats->free_blocks = ext4_free_blks_count(sb, desc);
 431                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
 432         } else {
 433                 stats->free_inodes = 0;
 434                 stats->free_blocks = 0;
 435                 stats->used_dirs = 0;
 436         }
 437 }
 438
 439 /*
 440  * Orlov's allocator for directories.
 441  *
 442  * We always try to spread first-level directories.
 443  *
 444  * If there are blockgroups with both free inodes and free blocks counts
 445  * not worse than average we return one with smallest directory count.
 446  * Otherwise we simply return a random group.
 447  *
 448  * For the rest rules look so:
 449  *
 450  * It's OK to put directory into a group unless
 451  * it has too many directories already (max_dirs) or
 452  * it has too few free inodes left (min_inodes) or
 453  * it has too few free blocks left (min_blocks) or
 454  * Parent's group is preferred, if it doesn't satisfy these
 455  * conditions we search cyclically through the rest. If none
 456  * of the groups look good we just look for a group with more
 457  * free inodes than average (starting at parent's group).
 458  */
 459
 460 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 461                             ext4_group_t *group, int mode,
 462                             const struct qstr *qstr)
 463 {
 464         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 465         struct ext4_sb_info *sbi = EXT4_SB(sb);
 466         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 467         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 468         unsigned int freei, avefreei;
 469         ext4_fsblk_t freeb, avefreeb;
 470         unsigned int ndirs;
 471         int max_dirs, min_inodes;
 472         ext4_grpblk_t min_blocks;
 473         ext4_group_t i, grp, g, ngroups;
 474         struct ext4_group_desc *desc;
 475         struct orlov_stats stats;
 476         int flex_size = ext4_flex_bg_size(sbi);
 477         struct dx_hash_info hinfo;
 478
 479         ngroups = real_ngroups;
 480         if (flex_size > 1) {
 481                 ngroups = (real_ngroups + flex_size - 1) >>
 482                         sbi->s_log_groups_per_flex;
 483                 parent_group >>= sbi->s_log_groups_per_flex;
 484         }
 485
 486         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 487         avefreei = freei / ngroups;
 488         freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 489         avefreeb = freeb;
 490         do_div(avefreeb, ngroups);
 491         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 492
 493         if (S_ISDIR(mode) &&
 494             ((parent == sb->s_root->d_inode) ||
 495              (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
 496                 int best_ndir = inodes_per_group;
 497                 int ret = -1;
 498
 499                 if (qstr) {
 500                         hinfo.hash_version = DX_HASH_HALF_MD4;
 501                         hinfo.seed = sbi->s_hash_seed;
 502                         ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
 503                         grp = hinfo.hash;
 504                 } else
 505                         get_random_bytes(&grp, sizeof(grp));
 506                 parent_group = (unsigned)grp % ngroups;
 507                 for (i = 0; i < ngroups; i++) {
 508                         g = (parent_group + i) % ngroups;
 509                         get_orlov_stats(sb, g, flex_size, &stats);
 510                         if (!stats.free_inodes)
 511                                 continue;
 512                         if (stats.used_dirs >= best_ndir)
 513                                 continue;
 514                         if (stats.free_inodes < avefreei)
 515                                 continue;
 516                         if (stats.free_blocks < avefreeb)
 517                                 continue;
 518                         grp = g;
 519                         ret = 0;
 520                         best_ndir = stats.used_dirs;
 521                 }
 522                 if (ret)
 523                         goto fallback;
 524         found_flex_bg:
 525                 if (flex_size == 1) {
 526                         *group = grp;
 527                         return 0;
 528                 }
 529
 530                 /*
 531                  * We pack inodes at the beginning of the flexgroup's
 532                  * inode tables.  Block allocation decisions will do
 533                  * something similar, although regular files will
 534                  * start at 2nd block group of the flexgroup.  See
 535                  * ext4_ext_find_goal() and ext4_find_near().
 536                  */
 537                 grp *= flex_size;
 538                 for (i = 0; i < flex_size; i++) {
 539                         if (grp+i >= real_ngroups)
 540                                 break;
 541                         desc = ext4_get_group_desc(sb, grp+i, NULL);
 542                         if (desc && ext4_free_inodes_count(sb, desc)) {
 543                                 *group = grp+i;
 544                                 return 0;
 545                         }
 546                 }
 547                 goto fallback;
 548         }
 549
 550         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 551         min_inodes = avefreei - inodes_per_group*flex_size / 4;
 552         if (min_inodes < 1)
 553                 min_inodes = 1;
 554         min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb)*flex_size / 4;
 555
 556         /*
 557          * Start looking in the flex group where we last allocated an
 558          * inode for this parent directory
 559          */
 560         if (EXT4_I(parent)->i_last_alloc_group != ~0) {
 561                 parent_group = EXT4_I(parent)->i_last_alloc_group;
 562                 if (flex_size > 1)
 563                         parent_group >>= sbi->s_log_groups_per_flex;
 564         }
 565
 566         for (i = 0; i < ngroups; i++) {
 567                 grp = (parent_group + i) % ngroups;
 568                 get_orlov_stats(sb, grp, flex_size, &stats);
 569                 if (stats.used_dirs >= max_dirs)
 570                         continue;
 571                 if (stats.free_inodes < min_inodes)
 572                         continue;
 573                 if (stats.free_blocks < min_blocks)
 574                         continue;
 575                 goto found_flex_bg;
 576         }
 577
 578 fallback:
 579         ngroups = real_ngroups;
 580         avefreei = freei / ngroups;
 581 fallback_retry:
 582         parent_group = EXT4_I(parent)->i_block_group;
 583         for (i = 0; i < ngroups; i++) {
 584                 grp = (parent_group + i) % ngroups;
 585                 desc = ext4_get_group_desc(sb, grp, NULL);
 586                 if (desc && ext4_free_inodes_count(sb, desc) &&
 587                     ext4_free_inodes_count(sb, desc) >= avefreei) {
 588                         *group = grp;
 589                         return 0;
 590                 }
 591         }
 592
 593         if (avefreei) {
 594                 /*
 595                  * The free-inodes counter is approximate, and for really small
 596                  * filesystems the above test can fail to find any blockgroups
 597                  */
 598                 avefreei = 0;
 599                 goto fallback_retry;
 600         }
 601
 602         return -1;
 603 }
 604
 605 static int find_group_other(struct super_block *sb, struct inode *parent,
 606                             ext4_group_t *group, int mode)
 607 {
 608         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 609         ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
 610         struct ext4_group_desc *desc;
 611         int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
 612
 613         /*
 614          * Try to place the inode is the same flex group as its
 615          * parent.  If we can't find space, use the Orlov algorithm to
 616          * find another flex group, and store that information in the
 617          * parent directory's inode information so that use that flex
 618          * group for future allocations.
 619          */
 620         if (flex_size > 1) {
 621                 int retry = 0;
 622
 623         try_again:
 624                 parent_group &= ~(flex_size-1);
 625                 last = parent_group + flex_size;
 626                 if (last > ngroups)
 627                         last = ngroups;
 628                 for  (i = parent_group; i < last; i++) {
 629                         desc = ext4_get_group_desc(sb, i, NULL);
 630                         if (desc && ext4_free_inodes_count(sb, desc)) {
 631                                 *group = i;
 632                                 return 0;
 633                         }
 634                 }
 635                 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
 636                         retry = 1;
 637                         parent_group = EXT4_I(parent)->i_last_alloc_group;
 638                         goto try_again;
 639                 }
 640                 /*
 641                  * If this didn't work, use the Orlov search algorithm
 642                  * to find a new flex group; we pass in the mode to
 643                  * avoid the topdir algorithms.
 644                  */
 645                 *group = parent_group + flex_size;
 646                 if (*group > ngroups)
 647                         *group = 0;
 648                 return find_group_orlov(sb, parent, group, mode, 0);
 649         }
 650
 651         /*
 652          * Try to place the inode in its parent directory
 653          */
 654         *group = parent_group;
 655         desc = ext4_get_group_desc(sb, *group, NULL);
 656         if (desc && ext4_free_inodes_count(sb, desc) &&
 657                         ext4_free_blks_count(sb, desc))
 658                 return 0;
 659
 660         /*
 661          * We're going to place this inode in a different blockgroup from its
 662          * parent.  We want to cause files in a common directory to all land in
 663          * the same blockgroup.  But we want files which are in a different
 664          * directory which shares a blockgroup with our parent to land in a
 665          * different blockgroup.
 666          *
 667          * So add our directory's i_ino into the starting point for the hash.
 668          */
 669         *group = (*group + parent->i_ino) % ngroups;
 670
 671         /*
 672          * Use a quadratic hash to find a group with a free inode and some free
 673          * blocks.
 674          */
 675         for (i = 1; i < ngroups; i <<= 1) {
 676                 *group += i;
 677                 if (*group >= ngroups)
 678                         *group -= ngroups;
 679                 desc = ext4_get_group_desc(sb, *group, NULL);
 680                 if (desc && ext4_free_inodes_count(sb, desc) &&
 681                                 ext4_free_blks_count(sb, desc))
 682                         return 0;
 683         }
 684
 685         /*
 686          * That failed: try linear search for a free inode, even if that group
 687          * has no free blocks.
 688          */
 689         *group = parent_group;
 690         for (i = 0; i < ngroups; i++) {
 691                 if (++*group >= ngroups)
 692                         *group = 0;
 693                 desc = ext4_get_group_desc(sb, *group, NULL);
 694                 if (desc && ext4_free_inodes_count(sb, desc))
 695                         return 0;
 696         }
 697
 698         return -1;
 699 }
 700
 701 /*
 702  * claim the inode from the inode bitmap. If the group
 703  * is uninit we need to take the groups's ext4_group_lock
 704  * and clear the uninit flag. The inode bitmap update
 705  * and group desc uninit flag clear should be done
 706  * after holding ext4_group_lock so that ext4_read_inode_bitmap
 707  * doesn't race with the ext4_claim_inode
 708  */
 709 static int ext4_claim_inode(struct super_block *sb,
 710                         struct buffer_head *inode_bitmap_bh,
 711                         unsigned long ino, ext4_group_t group, int mode)
 712 {
 713         int free = 0, retval = 0, count;
 714         struct ext4_sb_info *sbi = EXT4_SB(sb);
 715         struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
 716
 717         ext4_lock_group(sb, group);
 718         if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
 719                 /* not a free inode */
 720                 retval = 1;
 721                 goto err_ret;
 722         }
 723         ino++;
 724         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
 725                         ino > EXT4_INODES_PER_GROUP(sb)) {
 726                 ext4_unlock_group(sb, group);
 727                 ext4_error(sb, "reserved inode or inode > inodes count - "
 728                            "block_group = %u, inode=%lu", group,
 729                            ino + group * EXT4_INODES_PER_GROUP(sb));
 730                 return 1;
 731         }
 732         /* If we didn't allocate from within the initialized part of the inode
 733          * table then we need to initialize up to this inode. */
 734         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 735
 736                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 737                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 738                         /* When marking the block group with
 739                          * ~EXT4_BG_INODE_UNINIT we don't want to depend
 740                          * on the value of bg_itable_unused even though
 741                          * mke2fs could have initialized the same for us.
 742                          * Instead we calculated the value below
 743                          */
 744
 745                         free = 0;
 746                 } else {
 747                         free = EXT4_INODES_PER_GROUP(sb) -
 748                                 ext4_itable_unused_count(sb, gdp);
 749                 }
 750
 751                 /*
 752                  * Check the relative inode number against the last used
 753                  * relative inode number in this group. if it is greater
 754                  * we need to  update the bg_itable_unused count
 755                  *
 756                  */
 757                 if (ino > free)
 758                         ext4_itable_unused_set(sb, gdp,
 759                                         (EXT4_INODES_PER_GROUP(sb) - ino));
 760         }
 761         count = ext4_free_inodes_count(sb, gdp) - 1;
 762         ext4_free_inodes_set(sb, gdp, count);
 763         if (S_ISDIR(mode)) {
 764                 count = ext4_used_dirs_count(sb, gdp) + 1;
 765                 ext4_used_dirs_set(sb, gdp, count);
 766                 if (sbi->s_log_groups_per_flex) {
 767                         ext4_group_t f = ext4_flex_group(sbi, group);
 768
 769                         atomic_inc(&sbi->s_flex_groups[f].used_dirs);
 770                 }
 771         }
 772         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
 773 err_ret:
 774         ext4_unlock_group(sb, group);
 775         return retval;
 776 }
 777
 778 /*
 779  * There are two policies for allocating an inode.  If the new inode is
 780  * a directory, then a forward search is made for a block group with both
 781  * free space and a low directory-to-inode ratio; if that fails, then of
 782  * the groups with above-average free space, that group with the fewest
 783  * directories already is chosen.
 784  *
 785  * For other inodes, search forward from the parent directory's block
 786  * group to find a free inode.
 787  */
 788 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode,
 789                              const struct qstr *qstr, __u32 goal)
 790 {
 791         struct super_block *sb;
 792         struct buffer_head *inode_bitmap_bh = NULL;
 793         struct buffer_head *group_desc_bh;
 794         ext4_group_t ngroups, group = 0;
 795         unsigned long ino = 0;
 796         struct inode *inode;
 797         struct ext4_group_desc *gdp = NULL;
 798         struct ext4_inode_info *ei;
 799         struct ext4_sb_info *sbi;
 800         int ret2, err = 0;
 801         struct inode *ret;
 802         ext4_group_t i;
 803         int free = 0;
 804         static int once = 1;
 805         ext4_group_t flex_group;
 806
 807         /* Cannot create files in a deleted directory */
 808         if (!dir || !dir->i_nlink)
 809                 return ERR_PTR(-EPERM);
 810
 811         sb = dir->i_sb;
 812         ngroups = ext4_get_groups_count(sb);
 813         trace_ext4_request_inode(dir, mode);
 814         inode = new_inode(sb);
 815         if (!inode)
 816                 return ERR_PTR(-ENOMEM);
 817         ei = EXT4_I(inode);
 818         sbi = EXT4_SB(sb);
 819
 820         if (!goal)
 821                 goal = sbi->s_inode_goal;
 822
 823         if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
 824                 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
 825                 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
 826                 ret2 = 0;
 827                 goto got_group;
 828         }
 829
 830         if (sbi->s_log_groups_per_flex && test_opt(sb, OLDALLOC)) {
 831                 ret2 = find_group_flex(sb, dir, &group);
 832                 if (ret2 == -1) {
 833                         ret2 = find_group_other(sb, dir, &group, mode);
 834                         if (ret2 == 0 && once) {
 835                                 once = 0;
 836                                 printk(KERN_NOTICE "ext4: find_group_flex "
 837                                        "failed, fallback succeeded dir %lu\n",
 838                                        dir->i_ino);
 839                         }
 840                 }
 841                 goto got_group;
 842         }
 843
 844         if (S_ISDIR(mode)) {
 845                 if (test_opt(sb, OLDALLOC))
 846                         ret2 = find_group_dir(sb, dir, &group);
 847                 else
 848                         ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
 849         } else
 850                 ret2 = find_group_other(sb, dir, &group, mode);
 851
 852 got_group:
 853         EXT4_I(dir)->i_last_alloc_group = group;
 854         err = -ENOSPC;
 855         if (ret2 == -1)
 856                 goto out;
 857
 858         for (i = 0; i < ngroups; i++, ino = 0) {
 859                 err = -EIO;
 860
 861                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 862                 if (!gdp)
 863                         goto fail;
 864
 865                 brelse(inode_bitmap_bh);
 866                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 867                 if (!inode_bitmap_bh)
 868                         goto fail;
 869
 870 repeat_in_this_group:
 871                 ino = ext4_find_next_zero_bit((unsigned long *)
 872                                               inode_bitmap_bh->b_data,
 873                                               EXT4_INODES_PER_GROUP(sb), ino);
 874
 875                 if (ino < EXT4_INODES_PER_GROUP(sb)) {
 876
 877                         BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 878                         err = ext4_journal_get_write_access(handle,
 879                                                             inode_bitmap_bh);
 880                         if (err)
 881                                 goto fail;
 882
 883                         BUFFER_TRACE(group_desc_bh, "get_write_access");
 884                         err = ext4_journal_get_write_access(handle,
 885                                                                 group_desc_bh);
 886                         if (err)
 887                                 goto fail;
 888                         if (!ext4_claim_inode(sb, inode_bitmap_bh,
 889                                                 ino, group, mode)) {
 890                                 /* we won it */
 891                                 BUFFER_TRACE(inode_bitmap_bh,
 892                                         "call ext4_handle_dirty_metadata");
 893                                 err = ext4_handle_dirty_metadata(handle,
 894                                                                  NULL,
 895                                                         inode_bitmap_bh);
 896                                 if (err)
 897                                         goto fail;
 898                                 /* zero bit is inode number 1*/
 899                                 ino++;
 900                                 goto got;
 901                         }
 902                         /* we lost it */
 903                         ext4_handle_release_buffer(handle, inode_bitmap_bh);
 904                         ext4_handle_release_buffer(handle, group_desc_bh);
 905
 906                         if (++ino < EXT4_INODES_PER_GROUP(sb))
 907                                 goto repeat_in_this_group;
 908                 }
 909
 910                 /*
 911                  * This case is possible in concurrent environment.  It is very
 912                  * rare.  We cannot repeat the find_group_xxx() call because
 913                  * that will simply return the same blockgroup, because the
 914                  * group descriptor metadata has not yet been updated.
 915                  * So we just go onto the next blockgroup.
 916                  */
 917                 if (++group == ngroups)
 918                         group = 0;
 919         }
 920         err = -ENOSPC;
 921         goto out;
 922
 923 got:
 924         /* We may have to initialize the block bitmap if it isn't already */
 925         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
 926             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 927                 struct buffer_head *block_bitmap_bh;
 928
 929                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 930                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 931                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 932                 if (err) {
 933                         brelse(block_bitmap_bh);
 934                         goto fail;
 935                 }
 936
 937                 free = 0;
 938                 ext4_lock_group(sb, group);
 939                 /* recheck and clear flag under lock if we still need to */
 940                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 941                         free = ext4_free_blocks_after_init(sb, group, gdp);
 942                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 943                         ext4_free_blks_set(sb, gdp, free);
 944                         gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
 945                                                                 gdp);
 946                 }
 947                 ext4_unlock_group(sb, group);
 948
 949                 /* Don't need to dirty bitmap block if we didn't change it */
 950                 if (free) {
 951                         BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
 952                         err = ext4_handle_dirty_metadata(handle,
 953                                                         NULL, block_bitmap_bh);
 954                 }
 955
 956                 brelse(block_bitmap_bh);
 957                 if (err)
 958                         goto fail;
 959         }
 960         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
 961         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
 962         if (err)
 963                 goto fail;
 964
 965         percpu_counter_dec(&sbi->s_freeinodes_counter);
 966         if (S_ISDIR(mode))
 967                 percpu_counter_inc(&sbi->s_dirs_counter);
 968         ext4_mark_super_dirty(sb);
 969
 970         if (sbi->s_log_groups_per_flex) {
 971                 flex_group = ext4_flex_group(sbi, group);
 972                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
 973         }
 974
 975         if (test_opt(sb, GRPID)) {
 976                 inode->i_mode = mode;
 977                 inode->i_uid = current_fsuid();
 978                 inode->i_gid = dir->i_gid;
 979         } else
 980                 inode_init_owner(inode, dir, mode);
 981
 982         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
 983         /* This is the optimal IO size (for stat), not the fs block size */
 984         inode->i_blocks = 0;
 985         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
 986                                                        ext4_current_time(inode);
 987
 988         memset(ei->i_data, 0, sizeof(ei->i_data));
 989         ei->i_dir_start_lookup = 0;
 990         ei->i_disksize = 0;
 991
 992         /*
 993          * Don't inherit extent flag from directory, amongst others. We set
 994          * extent flag on newly created directory and file only if -o extent
 995          * mount option is specified
 996          */
 997         ei->i_flags =
 998                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
 999         ei->i_file_acl = 0;
1000         ei->i_dtime = 0;
1001         ei->i_block_group = group;
1002         ei->i_last_alloc_group = ~0;
1003
1004         ext4_set_inode_flags(inode);
1005         if (IS_DIRSYNC(inode))
1006                 ext4_handle_sync(handle);
1007         if (insert_inode_locked(inode) < 0) {
1008                 err = -EINVAL;
1009                 goto fail_drop;
1010         }
1011         spin_lock(&sbi->s_next_gen_lock);
1012         inode->i_generation = sbi->s_next_generation++;
1013         spin_unlock(&sbi->s_next_gen_lock);
1014
1015         ei->i_state_flags = 0;
1016         ext4_set_inode_state(inode, EXT4_STATE_NEW);
1017
1018         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
1019
1020         ret = inode;
1021         dquot_initialize(inode);
1022         err = dquot_alloc_inode(inode);
1023         if (err)
1024                 goto fail_drop;
1025
1026         err = ext4_init_acl(handle, inode, dir);
1027         if (err)
1028                 goto fail_free_drop;
1029
1030         err = ext4_init_security(handle, inode, dir);
1031         if (err)
1032                 goto fail_free_drop;
1033
1034         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
1035                 /* set extent flag only for directory, file and normal symlink*/
1036                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1037                         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1038                         ext4_ext_tree_init(handle, inode);
1039                 }
1040         }
1041
1042         err = ext4_mark_inode_dirty(handle, inode);
1043         if (err) {
1044                 ext4_std_error(sb, err);
1045                 goto fail_free_drop;
1046         }
1047
1048         ext4_debug("allocating inode %lu\n", inode->i_ino);
1049         trace_ext4_allocate_inode(inode, dir, mode);
1050         goto really_out;
1051 fail:
1052         ext4_std_error(sb, err);
1053 out:
1054         iput(inode);
1055         ret = ERR_PTR(err);
1056 really_out:
1057         brelse(inode_bitmap_bh);
1058         return ret;
1059
1060 fail_free_drop:
1061         dquot_free_inode(inode);
1062
1063 fail_drop:
1064         dquot_drop(inode);
1065         inode->i_flags |= S_NOQUOTA;
1066         inode->i_nlink = 0;
1067         unlock_new_inode(inode);
1068         iput(inode);
1069         brelse(inode_bitmap_bh);
1070         return ERR_PTR(err);
1071 }
1072
1073 /* Verify that we are loading a valid orphan from disk */
1074 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1075 {
1076         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1077         ext4_group_t block_group;
1078         int bit;
1079         struct buffer_head *bitmap_bh;
1080         struct inode *inode = NULL;
1081         long err = -EIO;
1082
1083         /* Error cases - e2fsck has already cleaned up for us */
1084         if (ino > max_ino) {
1085                 ext4_warning(sb, "bad orphan ino %lu!  e2fsck was run?", ino);
1086                 goto error;
1087         }
1088
1089         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1090         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1091         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1092         if (!bitmap_bh) {
1093                 ext4_warning(sb, "inode bitmap error for orphan %lu", ino);
1094                 goto error;
1095         }
1096
1097         /* Having the inode bit set should be a 100% indicator that this
1098          * is a valid orphan (no e2fsck run on fs).  Orphans also include
1099          * inodes that were being truncated, so we can't check i_nlink==0.
1100          */
1101         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1102                 goto bad_orphan;
1103
1104         inode = ext4_iget(sb, ino);
1105         if (IS_ERR(inode))
1106                 goto iget_failed;
1107
1108         /*
1109          * If the orphans has i_nlinks > 0 then it should be able to be
1110          * truncated, otherwise it won't be removed from the orphan list
1111          * during processing and an infinite loop will result.
1112          */
1113         if (inode->i_nlink && !ext4_can_truncate(inode))
1114                 goto bad_orphan;
1115
1116         if (NEXT_ORPHAN(inode) > max_ino)
1117                 goto bad_orphan;
1118         brelse(bitmap_bh);
1119         return inode;
1120
1121 iget_failed:
1122         err = PTR_ERR(inode);
1123         inode = NULL;
1124 bad_orphan:
1125         ext4_warning(sb, "bad orphan inode %lu!  e2fsck was run?", ino);
1126         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1127                bit, (unsigned long long)bitmap_bh->b_blocknr,
1128                ext4_test_bit(bit, bitmap_bh->b_data));
1129         printk(KERN_NOTICE "inode=%p\n", inode);
1130         if (inode) {
1131                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
1132                        is_bad_inode(inode));
1133                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
1134                        NEXT_ORPHAN(inode));
1135                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
1136                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
1137                 /* Avoid freeing blocks if we got a bad deleted inode */
1138                 if (inode->i_nlink == 0)
1139                         inode->i_blocks = 0;
1140                 iput(inode);
1141         }
1142         brelse(bitmap_bh);
1143 error:
1144         return ERR_PTR(err);
1145 }
1146
1147 unsigned long ext4_count_free_inodes(struct super_block *sb)
1148 {
1149         unsigned long desc_count;
1150         struct ext4_group_desc *gdp;
1151         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1152 #ifdef EXT4FS_DEBUG
1153         struct ext4_super_block *es;
1154         unsigned long bitmap_count, x;
1155         struct buffer_head *bitmap_bh = NULL;
1156
1157         es = EXT4_SB(sb)->s_es;
1158         desc_count = 0;
1159         bitmap_count = 0;
1160         gdp = NULL;
1161         for (i = 0; i < ngroups; i++) {
1162                 gdp = ext4_get_group_desc(sb, i, NULL);
1163                 if (!gdp)
1164                         continue;
1165                 desc_count += ext4_free_inodes_count(sb, gdp);
1166                 brelse(bitmap_bh);
1167                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1168                 if (!bitmap_bh)
1169                         continue;
1170
1171                 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
1172                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1173                         (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1174                 bitmap_count += x;
1175         }
1176         brelse(bitmap_bh);
1177         printk(KERN_DEBUG "ext4_count_free_inodes: "
1178                "stored = %u, computed = %lu, %lu\n",
1179                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1180         return desc_count;
1181 #else
1182         desc_count = 0;
1183         for (i = 0; i < ngroups; i++) {
1184                 gdp = ext4_get_group_desc(sb, i, NULL);
1185                 if (!gdp)
1186                         continue;
1187                 desc_count += ext4_free_inodes_count(sb, gdp);
1188                 cond_resched();
1189         }
1190         return desc_count;
1191 #endif
1192 }
1193
1194 /* Called at mount-time, super-block is locked */
1195 unsigned long ext4_count_dirs(struct super_block * sb)
1196 {
1197         unsigned long count = 0;
1198         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1199
1200         for (i = 0; i < ngroups; i++) {
1201                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1202                 if (!gdp)
1203                         continue;
1204                 count += ext4_used_dirs_count(sb, gdp);
1205         }
1206         return count;
1207 }