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 #include "ext4.h"
  27 #include "ext4_jbd2.h"
  28 #include "xattr.h"
  29 #include "acl.h"
  30
  31 /*
  32  * ialloc.c contains the inodes allocation and deallocation routines
  33  */
  34
  35 /*
  36  * The free inodes are managed by bitmaps.  A file system contains several
  37  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  38  * block for inodes, N blocks for the inode table and data blocks.
  39  *
  40  * The file system contains group descriptors which are located after the
  41  * super block.  Each descriptor contains the number of the bitmap block and
  42  * the free blocks count in the block.
  43  */
  44
  45 /*
  46  * To avoid calling the atomic setbit hundreds or thousands of times, we only
  47  * need to use it within a single byte (to ensure we get endianness right).
  48  * We can use memset for the rest of the bitmap as there are no other users.
  49  */
  50 void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
  51 {
  52         int i;
  53
  54         if (start_bit >= end_bit)
  55                 return;
  56
  57         ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
  58         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
  59                 ext4_set_bit(i, bitmap);
  60         if (i < end_bit)
  61                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
  62 }
  63
  64 /* Initializes an uninitialized inode bitmap */
  65 unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh,
  66                                 ext4_group_t block_group,
  67                                 struct ext4_group_desc *gdp)
  68 {
  69         struct ext4_sb_info *sbi = EXT4_SB(sb);
  70
  71         J_ASSERT_BH(bh, buffer_locked(bh));
  72
  73         /* If checksum is bad mark all blocks and inodes use to prevent
  74          * allocation, essentially implementing a per-group read-only flag. */
  75         if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
  76                 ext4_error(sb, __func__, "Checksum bad for group %u",
  77                            block_group);
  78                 ext4_free_blks_set(sb, gdp, 0);
  79                 ext4_free_inodes_set(sb, gdp, 0);
  80                 ext4_itable_unused_set(sb, gdp, 0);
  81                 memset(bh->b_data, 0xff, sb->s_blocksize);
  82                 return 0;
  83         }
  84
  85         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
  86         mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
  87                         bh->b_data);
  88
  89         return EXT4_INODES_PER_GROUP(sb);
  90 }
  91
  92 /*
  93  * Read the inode allocation bitmap for a given block_group, reading
  94  * into the specified slot in the superblock's bitmap cache.
  95  *
  96  * Return buffer_head of bitmap on success or NULL.
  97  */
  98 static struct buffer_head *
  99 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 100 {
 101         struct ext4_group_desc *desc;
 102         struct buffer_head *bh = NULL;
 103         ext4_fsblk_t bitmap_blk;
 104
 105         desc = ext4_get_group_desc(sb, block_group, NULL);
 106         if (!desc)
 107                 return NULL;
 108         bitmap_blk = ext4_inode_bitmap(sb, desc);
 109         bh = sb_getblk(sb, bitmap_blk);
 110         if (unlikely(!bh)) {
 111                 ext4_error(sb, __func__,
 112                             "Cannot read inode bitmap - "
 113                             "block_group = %u, inode_bitmap = %llu",
 114                             block_group, bitmap_blk);
 115                 return NULL;
 116         }
 117         if (bitmap_uptodate(bh))
 118                 return bh;
 119
 120         lock_buffer(bh);
 121         if (bitmap_uptodate(bh)) {
 122                 unlock_buffer(bh);
 123                 return bh;
 124         }
 125         ext4_lock_group(sb, block_group);
 126         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 127                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
 128                 set_bitmap_uptodate(bh);
 129                 set_buffer_uptodate(bh);
 130                 ext4_unlock_group(sb, block_group);
 131                 unlock_buffer(bh);
 132                 return bh;
 133         }
 134         ext4_unlock_group(sb, block_group);
 135         if (buffer_uptodate(bh)) {
 136                 /*
 137                  * if not uninit if bh is uptodate,
 138                  * bitmap is also uptodate
 139                  */
 140                 set_bitmap_uptodate(bh);
 141                 unlock_buffer(bh);
 142                 return bh;
 143         }
 144         /*
 145          * submit the buffer_head for read. We can
 146          * safely mark the bitmap as uptodate now.
 147          * We do it here so the bitmap uptodate bit
 148          * get set with buffer lock held.
 149          */
 150         set_bitmap_uptodate(bh);
 151         if (bh_submit_read(bh) < 0) {
 152                 put_bh(bh);
 153                 ext4_error(sb, __func__,
 154                             "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_mark(ext4_free_inode,
 212                    "dev %s ino %lu mode %d uid %lu gid %lu bocks %llu",
 213                    sb->s_id, inode->i_ino, inode->i_mode,
 214                    (unsigned long) inode->i_uid, (unsigned long) inode->i_gid,
 215                    (unsigned long long) inode->i_blocks);
 216
 217         /*
 218          * Note: we must free any quota before locking the superblock,
 219          * as writing the quota to disk may need the lock as well.
 220          */
 221         vfs_dq_init(inode);
 222         ext4_xattr_delete_inode(handle, inode);
 223         vfs_dq_free_inode(inode);
 224         vfs_dq_drop(inode);
 225
 226         is_directory = S_ISDIR(inode->i_mode);
 227
 228         /* Do this BEFORE marking the inode not in use or returning an error */
 229         clear_inode(inode);
 230
 231         es = EXT4_SB(sb)->s_es;
 232         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 233                 ext4_error(sb, "ext4_free_inode",
 234                            "reserved or nonexistent inode %lu", ino);
 235                 goto error_return;
 236         }
 237         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 238         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 239         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 240         if (!bitmap_bh)
 241                 goto error_return;
 242
 243         BUFFER_TRACE(bitmap_bh, "get_write_access");
 244         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 245         if (fatal)
 246                 goto error_return;
 247
 248         /* Ok, now we can actually update the inode bitmaps.. */
 249         cleared = ext4_clear_bit_atomic(ext4_group_lock_ptr(sb, block_group),
 250                                         bit, bitmap_bh->b_data);
 251         if (!cleared)
 252                 ext4_error(sb, "ext4_free_inode",
 253                            "bit already cleared for inode %lu", ino);
 254         else {
 255                 gdp = ext4_get_group_desc(sb, block_group, &bh2);
 256
 257                 BUFFER_TRACE(bh2, "get_write_access");
 258                 fatal = ext4_journal_get_write_access(handle, bh2);
 259                 if (fatal) goto error_return;
 260
 261                 if (gdp) {
 262                         ext4_lock_group(sb, block_group);
 263                         count = ext4_free_inodes_count(sb, gdp) + 1;
 264                         ext4_free_inodes_set(sb, gdp, count);
 265                         if (is_directory) {
 266                                 count = ext4_used_dirs_count(sb, gdp) - 1;
 267                                 ext4_used_dirs_set(sb, gdp, count);
 268                                 if (sbi->s_log_groups_per_flex) {
 269                                         ext4_group_t f;
 270
 271                                         f = ext4_flex_group(sbi, block_group);
 272                                         atomic_dec(&sbi->s_flex_groups[f].free_inodes);
 273                                 }
 274
 275                         }
 276                         gdp->bg_checksum = ext4_group_desc_csum(sbi,
 277                                                         block_group, gdp);
 278                         ext4_unlock_group(sb, block_group);
 279                         percpu_counter_inc(&sbi->s_freeinodes_counter);
 280                         if (is_directory)
 281                                 percpu_counter_dec(&sbi->s_dirs_counter);
 282
 283                         if (sbi->s_log_groups_per_flex) {
 284                                 ext4_group_t f;
 285
 286                                 f = ext4_flex_group(sbi, block_group);
 287                                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 288                         }
 289                 }
 290                 BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 291                 err = ext4_handle_dirty_metadata(handle, NULL, bh2);
 292                 if (!fatal) fatal = err;
 293         }
 294         BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 295         err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 296         if (!fatal)
 297                 fatal = err;
 298         sb->s_dirt = 1;
 299 error_return:
 300         brelse(bitmap_bh);
 301         ext4_std_error(sb, fatal);
 302 }
 303
 304 /*
 305  * There are two policies for allocating an inode.  If the new inode is
 306  * a directory, then a forward search is made for a block group with both
 307  * free space and a low directory-to-inode ratio; if that fails, then of
 308  * the groups with above-average free space, that group with the fewest
 309  * directories already is chosen.
 310  *
 311  * For other inodes, search forward from the parent directory\'s block
 312  * group to find a free inode.
 313  */
 314 static int find_group_dir(struct super_block *sb, struct inode *parent,
 315                                 ext4_group_t *best_group)
 316 {
 317         ext4_group_t ngroups = ext4_get_groups_count(sb);
 318         unsigned int freei, avefreei;
 319         struct ext4_group_desc *desc, *best_desc = NULL;
 320         ext4_group_t group;
 321         int ret = -1;
 322
 323         freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
 324         avefreei = freei / ngroups;
 325
 326         for (group = 0; group < ngroups; group++) {
 327                 desc = ext4_get_group_desc(sb, group, NULL);
 328                 if (!desc || !ext4_free_inodes_count(sb, desc))
 329                         continue;
 330                 if (ext4_free_inodes_count(sb, desc) < avefreei)
 331                         continue;
 332                 if (!best_desc ||
 333                     (ext4_free_blks_count(sb, desc) >
 334                      ext4_free_blks_count(sb, best_desc))) {
 335                         *best_group = group;
 336                         best_desc = desc;
 337                         ret = 0;
 338                 }
 339         }
 340         return ret;
 341 }
 342
 343 #define free_block_ratio 10
 344
 345 static int find_group_flex(struct super_block *sb, struct inode *parent,
 346                            ext4_group_t *best_group)
 347 {
 348         struct ext4_sb_info *sbi = EXT4_SB(sb);
 349         struct ext4_group_desc *desc;
 350         struct flex_groups *flex_group = sbi->s_flex_groups;
 351         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 352         ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
 353         ext4_group_t ngroups = ext4_get_groups_count(sb);
 354         int flex_size = ext4_flex_bg_size(sbi);
 355         ext4_group_t best_flex = parent_fbg_group;
 356         int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
 357         int flexbg_free_blocks;
 358         int flex_freeb_ratio;
 359         ext4_group_t n_fbg_groups;
 360         ext4_group_t i;
 361
 362         n_fbg_groups = (ngroups + flex_size - 1) >>
 363                 sbi->s_log_groups_per_flex;
 364
 365 find_close_to_parent:
 366         flexbg_free_blocks = atomic_read(&flex_group[best_flex].free_blocks);
 367         flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 368         if (atomic_read(&flex_group[best_flex].free_inodes) &&
 369             flex_freeb_ratio > free_block_ratio)
 370                 goto found_flexbg;
 371
 372         if (best_flex && best_flex == parent_fbg_group) {
 373                 best_flex--;
 374                 goto find_close_to_parent;
 375         }
 376
 377         for (i = 0; i < n_fbg_groups; i++) {
 378                 if (i == parent_fbg_group || i == parent_fbg_group - 1)
 379                         continue;
 380
 381                 flexbg_free_blocks = atomic_read(&flex_group[i].free_blocks);
 382                 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 383
 384                 if (flex_freeb_ratio > free_block_ratio &&
 385                     (atomic_read(&flex_group[i].free_inodes))) {
 386                         best_flex = i;
 387                         goto found_flexbg;
 388                 }
 389
 390                 if ((atomic_read(&flex_group[best_flex].free_inodes) == 0) ||
 391                     ((atomic_read(&flex_group[i].free_blocks) >
 392                       atomic_read(&flex_group[best_flex].free_blocks)) &&
 393                      atomic_read(&flex_group[i].free_inodes)))
 394                         best_flex = i;
 395         }
 396
 397         if (!atomic_read(&flex_group[best_flex].free_inodes) ||
 398             !atomic_read(&flex_group[best_flex].free_blocks))
 399                 return -1;
 400
 401 found_flexbg:
 402         for (i = best_flex * flex_size; i < ngroups &&
 403                      i < (best_flex + 1) * flex_size; i++) {
 404                 desc = ext4_get_group_desc(sb, i, NULL);
 405                 if (ext4_free_inodes_count(sb, desc)) {
 406                         *best_group = i;
 407                         goto out;
 408                 }
 409         }
 410
 411         return -1;
 412 out:
 413         return 0;
 414 }
 415
 416 struct orlov_stats {
 417         __u32 free_inodes;
 418         __u32 free_blocks;
 419         __u32 used_dirs;
 420 };
 421
 422 /*
 423  * Helper function for Orlov's allocator; returns critical information
 424  * for a particular block group or flex_bg.  If flex_size is 1, then g
 425  * is a block group number; otherwise it is flex_bg number.
 426  */
 427 void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 428                        int flex_size, struct orlov_stats *stats)
 429 {
 430         struct ext4_group_desc *desc;
 431         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
 432
 433         if (flex_size > 1) {
 434                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
 435                 stats->free_blocks = atomic_read(&flex_group[g].free_blocks);
 436                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
 437                 return;
 438         }
 439
 440         desc = ext4_get_group_desc(sb, g, NULL);
 441         if (desc) {
 442                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
 443                 stats->free_blocks = ext4_free_blks_count(sb, desc);
 444                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
 445         } else {
 446                 stats->free_inodes = 0;
 447                 stats->free_blocks = 0;
 448                 stats->used_dirs = 0;
 449         }
 450 }
 451
 452 /*
 453  * Orlov's allocator for directories.
 454  *
 455  * We always try to spread first-level directories.
 456  *
 457  * If there are blockgroups with both free inodes and free blocks counts
 458  * not worse than average we return one with smallest directory count.
 459  * Otherwise we simply return a random group.
 460  *
 461  * For the rest rules look so:
 462  *
 463  * It's OK to put directory into a group unless
 464  * it has too many directories already (max_dirs) or
 465  * it has too few free inodes left (min_inodes) or
 466  * it has too few free blocks left (min_blocks) or
 467  * Parent's group is preferred, if it doesn't satisfy these
 468  * conditions we search cyclically through the rest. If none
 469  * of the groups look good we just look for a group with more
 470  * free inodes than average (starting at parent's group).
 471  */
 472
 473 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 474                             ext4_group_t *group, int mode)
 475 {
 476         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 477         struct ext4_sb_info *sbi = EXT4_SB(sb);
 478         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 479         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 480         unsigned int freei, avefreei;
 481         ext4_fsblk_t freeb, avefreeb;
 482         unsigned int ndirs;
 483         int max_dirs, min_inodes;
 484         ext4_grpblk_t min_blocks;
 485         ext4_group_t i, grp, g, ngroups;
 486         struct ext4_group_desc *desc;
 487         struct orlov_stats stats;
 488         int flex_size = ext4_flex_bg_size(sbi);
 489
 490         ngroups = real_ngroups;
 491         if (flex_size > 1) {
 492                 ngroups = (real_ngroups + flex_size - 1) >>
 493                         sbi->s_log_groups_per_flex;
 494                 parent_group >>= sbi->s_log_groups_per_flex;
 495         }
 496
 497         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 498         avefreei = freei / ngroups;
 499         freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 500         avefreeb = freeb;
 501         do_div(avefreeb, ngroups);
 502         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 503
 504         if (S_ISDIR(mode) &&
 505             ((parent == sb->s_root->d_inode) ||
 506              (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL))) {
 507                 int best_ndir = inodes_per_group;
 508                 int ret = -1;
 509
 510                 get_random_bytes(&grp, sizeof(grp));
 511                 parent_group = (unsigned)grp % ngroups;
 512                 for (i = 0; i < ngroups; i++) {
 513                         g = (parent_group + i) % ngroups;
 514                         get_orlov_stats(sb, g, flex_size, &stats);
 515                         if (!stats.free_inodes)
 516                                 continue;
 517                         if (stats.used_dirs >= best_ndir)
 518                                 continue;
 519                         if (stats.free_inodes < avefreei)
 520                                 continue;
 521                         if (stats.free_blocks < avefreeb)
 522                                 continue;
 523                         grp = g;
 524                         ret = 0;
 525                         best_ndir = stats.used_dirs;
 526                 }
 527                 if (ret)
 528                         goto fallback;
 529         found_flex_bg:
 530                 if (flex_size == 1) {
 531                         *group = grp;
 532                         return 0;
 533                 }
 534
 535                 /*
 536                  * We pack inodes at the beginning of the flexgroup's
 537                  * inode tables.  Block allocation decisions will do
 538                  * something similar, although regular files will
 539                  * start at 2nd block group of the flexgroup.  See
 540                  * ext4_ext_find_goal() and ext4_find_near().
 541                  */
 542                 grp *= flex_size;
 543                 for (i = 0; i < flex_size; i++) {
 544                         if (grp+i >= real_ngroups)
 545                                 break;
 546                         desc = ext4_get_group_desc(sb, grp+i, NULL);
 547                         if (desc && ext4_free_inodes_count(sb, desc)) {
 548                                 *group = grp+i;
 549                                 return 0;
 550                         }
 551                 }
 552                 goto fallback;
 553         }
 554
 555         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 556         min_inodes = avefreei - inodes_per_group*flex_size / 4;
 557         if (min_inodes < 1)
 558                 min_inodes = 1;
 559         min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb)*flex_size / 4;
 560
 561         /*
 562          * Start looking in the flex group where we last allocated an
 563          * inode for this parent directory
 564          */
 565         if (EXT4_I(parent)->i_last_alloc_group != ~0) {
 566                 parent_group = EXT4_I(parent)->i_last_alloc_group;
 567                 if (flex_size > 1)
 568                         parent_group >>= sbi->s_log_groups_per_flex;
 569         }
 570
 571         for (i = 0; i < ngroups; i++) {
 572                 grp = (parent_group + i) % ngroups;
 573                 get_orlov_stats(sb, grp, flex_size, &stats);
 574                 if (stats.used_dirs >= max_dirs)
 575                         continue;
 576                 if (stats.free_inodes < min_inodes)
 577                         continue;
 578                 if (stats.free_blocks < min_blocks)
 579                         continue;
 580                 goto found_flex_bg;
 581         }
 582
 583 fallback:
 584         ngroups = real_ngroups;
 585         avefreei = freei / ngroups;
 586 fallback_retry:
 587         parent_group = EXT4_I(parent)->i_block_group;
 588         for (i = 0; i < ngroups; i++) {
 589                 grp = (parent_group + i) % ngroups;
 590                 desc = ext4_get_group_desc(sb, grp, NULL);
 591                 if (desc && ext4_free_inodes_count(sb, desc) &&
 592                     ext4_free_inodes_count(sb, desc) >= avefreei) {
 593                         *group = grp;
 594                         return 0;
 595                 }
 596         }
 597
 598         if (avefreei) {
 599                 /*
 600                  * The free-inodes counter is approximate, and for really small
 601                  * filesystems the above test can fail to find any blockgroups
 602                  */
 603                 avefreei = 0;
 604                 goto fallback_retry;
 605         }
 606
 607         return -1;
 608 }
 609
 610 static int find_group_other(struct super_block *sb, struct inode *parent,
 611                             ext4_group_t *group, int mode)
 612 {
 613         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 614         ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
 615         struct ext4_group_desc *desc;
 616         int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
 617
 618         /*
 619          * Try to place the inode is the same flex group as its
 620          * parent.  If we can't find space, use the Orlov algorithm to
 621          * find another flex group, and store that information in the
 622          * parent directory's inode information so that use that flex
 623          * group for future allocations.
 624          */
 625         if (flex_size > 1) {
 626                 int retry = 0;
 627
 628         try_again:
 629                 parent_group &= ~(flex_size-1);
 630                 last = parent_group + flex_size;
 631                 if (last > ngroups)
 632                         last = ngroups;
 633                 for  (i = parent_group; i < last; i++) {
 634                         desc = ext4_get_group_desc(sb, i, NULL);
 635                         if (desc && ext4_free_inodes_count(sb, desc)) {
 636                                 *group = i;
 637                                 return 0;
 638                         }
 639                 }
 640                 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
 641                         retry = 1;
 642                         parent_group = EXT4_I(parent)->i_last_alloc_group;
 643                         goto try_again;
 644                 }
 645                 /*
 646                  * If this didn't work, use the Orlov search algorithm
 647                  * to find a new flex group; we pass in the mode to
 648                  * avoid the topdir algorithms.
 649                  */
 650                 *group = parent_group + flex_size;
 651                 if (*group > ngroups)
 652                         *group = 0;
 653                 return find_group_orlov(sb, parent, group, mode);
 654         }
 655
 656         /*
 657          * Try to place the inode in its parent directory
 658          */
 659         *group = parent_group;
 660         desc = ext4_get_group_desc(sb, *group, NULL);
 661         if (desc && ext4_free_inodes_count(sb, desc) &&
 662                         ext4_free_blks_count(sb, desc))
 663                 return 0;
 664
 665         /*
 666          * We're going to place this inode in a different blockgroup from its
 667          * parent.  We want to cause files in a common directory to all land in
 668          * the same blockgroup.  But we want files which are in a different
 669          * directory which shares a blockgroup with our parent to land in a
 670          * different blockgroup.
 671          *
 672          * So add our directory's i_ino into the starting point for the hash.
 673          */
 674         *group = (*group + parent->i_ino) % ngroups;
 675
 676         /*
 677          * Use a quadratic hash to find a group with a free inode and some free
 678          * blocks.
 679          */
 680         for (i = 1; i < ngroups; i <<= 1) {
 681                 *group += i;
 682                 if (*group >= ngroups)
 683                         *group -= ngroups;
 684                 desc = ext4_get_group_desc(sb, *group, NULL);
 685                 if (desc && ext4_free_inodes_count(sb, desc) &&
 686                                 ext4_free_blks_count(sb, desc))
 687                         return 0;
 688         }
 689
 690         /*
 691          * That failed: try linear search for a free inode, even if that group
 692          * has no free blocks.
 693          */
 694         *group = parent_group;
 695         for (i = 0; i < ngroups; i++) {
 696                 if (++*group >= ngroups)
 697                         *group = 0;
 698                 desc = ext4_get_group_desc(sb, *group, NULL);
 699                 if (desc && ext4_free_inodes_count(sb, desc))
 700                         return 0;
 701         }
 702
 703         return -1;
 704 }
 705
 706 /*
 707  * claim the inode from the inode bitmap. If the group
 708  * is uninit we need to take the groups's ext4_group_lock
 709  * and clear the uninit flag. The inode bitmap update
 710  * and group desc uninit flag clear should be done
 711  * after holding ext4_group_lock so that ext4_read_inode_bitmap
 712  * doesn't race with the ext4_claim_inode
 713  */
 714 static int ext4_claim_inode(struct super_block *sb,
 715                         struct buffer_head *inode_bitmap_bh,
 716                         unsigned long ino, ext4_group_t group, int mode)
 717 {
 718         int free = 0, retval = 0, count;
 719         struct ext4_sb_info *sbi = EXT4_SB(sb);
 720         struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
 721
 722         ext4_lock_group(sb, group);
 723         if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
 724                 /* not a free inode */
 725                 retval = 1;
 726                 goto err_ret;
 727         }
 728         ino++;
 729         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
 730                         ino > EXT4_INODES_PER_GROUP(sb)) {
 731                 ext4_unlock_group(sb, group);
 732                 ext4_error(sb, __func__,
 733                            "reserved inode or inode > inodes count - "
 734                            "block_group = %u, inode=%lu", group,
 735                            ino + group * EXT4_INODES_PER_GROUP(sb));
 736                 return 1;
 737         }
 738         /* If we didn't allocate from within the initialized part of the inode
 739          * table then we need to initialize up to this inode. */
 740         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 741
 742                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 743                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 744                         /* When marking the block group with
 745                          * ~EXT4_BG_INODE_UNINIT we don't want to depend
 746                          * on the value of bg_itable_unused even though
 747                          * mke2fs could have initialized the same for us.
 748                          * Instead we calculated the value below
 749                          */
 750
 751                         free = 0;
 752                 } else {
 753                         free = EXT4_INODES_PER_GROUP(sb) -
 754                                 ext4_itable_unused_count(sb, gdp);
 755                 }
 756
 757                 /*
 758                  * Check the relative inode number against the last used
 759                  * relative inode number in this group. if it is greater
 760                  * we need to  update the bg_itable_unused count
 761                  *
 762                  */
 763                 if (ino > free)
 764                         ext4_itable_unused_set(sb, gdp,
 765                                         (EXT4_INODES_PER_GROUP(sb) - ino));
 766         }
 767         count = ext4_free_inodes_count(sb, gdp) - 1;
 768         ext4_free_inodes_set(sb, gdp, count);
 769         if (S_ISDIR(mode)) {
 770                 count = ext4_used_dirs_count(sb, gdp) + 1;
 771                 ext4_used_dirs_set(sb, gdp, count);
 772                 if (sbi->s_log_groups_per_flex) {
 773                         ext4_group_t f = ext4_flex_group(sbi, group);
 774
 775                         atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 776                 }
 777         }
 778         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
 779 err_ret:
 780         ext4_unlock_group(sb, group);
 781         return retval;
 782 }
 783
 784 /*
 785  * There are two policies for allocating an inode.  If the new inode is
 786  * a directory, then a forward search is made for a block group with both
 787  * free space and a low directory-to-inode ratio; if that fails, then of
 788  * the groups with above-average free space, that group with the fewest
 789  * directories already is chosen.
 790  *
 791  * For other inodes, search forward from the parent directory's block
 792  * group to find a free inode.
 793  */
 794 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
 795 {
 796         struct super_block *sb;
 797         struct buffer_head *inode_bitmap_bh = NULL;
 798         struct buffer_head *group_desc_bh;
 799         ext4_group_t ngroups, group = 0;
 800         unsigned long ino = 0;
 801         struct inode *inode;
 802         struct ext4_group_desc *gdp = NULL;
 803         struct ext4_inode_info *ei;
 804         struct ext4_sb_info *sbi;
 805         int ret2, err = 0;
 806         struct inode *ret;
 807         ext4_group_t i;
 808         int free = 0;
 809         static int once = 1;
 810         ext4_group_t flex_group;
 811
 812         /* Cannot create files in a deleted directory */
 813         if (!dir || !dir->i_nlink)
 814                 return ERR_PTR(-EPERM);
 815
 816         sb = dir->i_sb;
 817         ngroups = ext4_get_groups_count(sb);
 818         trace_mark(ext4_request_inode, "dev %s dir %lu mode %d", sb->s_id,
 819                    dir->i_ino, mode);
 820         inode = new_inode(sb);
 821         if (!inode)
 822                 return ERR_PTR(-ENOMEM);
 823         ei = EXT4_I(inode);
 824         sbi = EXT4_SB(sb);
 825
 826         if (sbi->s_log_groups_per_flex && test_opt(sb, OLDALLOC)) {
 827                 ret2 = find_group_flex(sb, dir, &group);
 828                 if (ret2 == -1) {
 829                         ret2 = find_group_other(sb, dir, &group, mode);
 830                         if (ret2 == 0 && once) {
 831                                 once = 0;
 832                                 printk(KERN_NOTICE "ext4: find_group_flex "
 833                                        "failed, fallback succeeded dir %lu\n",
 834                                        dir->i_ino);
 835                         }
 836                 }
 837                 goto got_group;
 838         }
 839
 840         if (S_ISDIR(mode)) {
 841                 if (test_opt(sb, OLDALLOC))
 842                         ret2 = find_group_dir(sb, dir, &group);
 843                 else
 844                         ret2 = find_group_orlov(sb, dir, &group, mode);
 845         } else
 846                 ret2 = find_group_other(sb, dir, &group, mode);
 847
 848 got_group:
 849         EXT4_I(dir)->i_last_alloc_group = group;
 850         err = -ENOSPC;
 851         if (ret2 == -1)
 852                 goto out;
 853
 854         for (i = 0; i < ngroups; i++) {
 855                 err = -EIO;
 856
 857                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 858                 if (!gdp)
 859                         goto fail;
 860
 861                 brelse(inode_bitmap_bh);
 862                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 863                 if (!inode_bitmap_bh)
 864                         goto fail;
 865
 866                 ino = 0;
 867
 868 repeat_in_this_group:
 869                 ino = ext4_find_next_zero_bit((unsigned long *)
 870                                               inode_bitmap_bh->b_data,
 871                                               EXT4_INODES_PER_GROUP(sb), ino);
 872
 873                 if (ino < EXT4_INODES_PER_GROUP(sb)) {
 874
 875                         BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 876                         err = ext4_journal_get_write_access(handle,
 877                                                             inode_bitmap_bh);
 878                         if (err)
 879                                 goto fail;
 880
 881                         BUFFER_TRACE(group_desc_bh, "get_write_access");
 882                         err = ext4_journal_get_write_access(handle,
 883                                                                 group_desc_bh);
 884                         if (err)
 885                                 goto fail;
 886                         if (!ext4_claim_inode(sb, inode_bitmap_bh,
 887                                                 ino, group, mode)) {
 888                                 /* we won it */
 889                                 BUFFER_TRACE(inode_bitmap_bh,
 890                                         "call ext4_handle_dirty_metadata");
 891                                 err = ext4_handle_dirty_metadata(handle,
 892                                                                  inode,
 893                                                         inode_bitmap_bh);
 894                                 if (err)
 895                                         goto fail;
 896                                 /* zero bit is inode number 1*/
 897                                 ino++;
 898                                 goto got;
 899                         }
 900                         /* we lost it */
 901                         ext4_handle_release_buffer(handle, inode_bitmap_bh);
 902                         ext4_handle_release_buffer(handle, group_desc_bh);
 903
 904                         if (++ino < EXT4_INODES_PER_GROUP(sb))
 905                                 goto repeat_in_this_group;
 906                 }
 907
 908                 /*
 909                  * This case is possible in concurrent environment.  It is very
 910                  * rare.  We cannot repeat the find_group_xxx() call because
 911                  * that will simply return the same blockgroup, because the
 912                  * group descriptor metadata has not yet been updated.
 913                  * So we just go onto the next blockgroup.
 914                  */
 915                 if (++group == ngroups)
 916                         group = 0;
 917         }
 918         err = -ENOSPC;
 919         goto out;
 920
 921 got:
 922         /* We may have to initialize the block bitmap if it isn't already */
 923         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
 924             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 925                 struct buffer_head *block_bitmap_bh;
 926
 927                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 928                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 929                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 930                 if (err) {
 931                         brelse(block_bitmap_bh);
 932                         goto fail;
 933                 }
 934
 935                 free = 0;
 936                 ext4_lock_group(sb, group);
 937                 /* recheck and clear flag under lock if we still need to */
 938                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 939                         free = ext4_free_blocks_after_init(sb, group, gdp);
 940                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 941                         ext4_free_blks_set(sb, gdp, free);
 942                         gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
 943                                                                 gdp);
 944                 }
 945                 ext4_unlock_group(sb, group);
 946
 947                 /* Don't need to dirty bitmap block if we didn't change it */
 948                 if (free) {
 949                         BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
 950                         err = ext4_handle_dirty_metadata(handle,
 951                                                         NULL, block_bitmap_bh);
 952                 }
 953
 954                 brelse(block_bitmap_bh);
 955                 if (err)
 956                         goto fail;
 957         }
 958         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
 959         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
 960         if (err)
 961                 goto fail;
 962
 963         percpu_counter_dec(&sbi->s_freeinodes_counter);
 964         if (S_ISDIR(mode))
 965                 percpu_counter_inc(&sbi->s_dirs_counter);
 966         sb->s_dirt = 1;
 967
 968         if (sbi->s_log_groups_per_flex) {
 969                 flex_group = ext4_flex_group(sbi, group);
 970                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
 971         }
 972
 973         inode->i_uid = current_fsuid();
 974         if (test_opt(sb, GRPID))
 975                 inode->i_gid = dir->i_gid;
 976         else if (dir->i_mode & S_ISGID) {
 977                 inode->i_gid = dir->i_gid;
 978                 if (S_ISDIR(mode))
 979                         mode |= S_ISGID;
 980         } else
 981                 inode->i_gid = current_fsgid();
 982         inode->i_mode = mode;
 983
 984         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
 985         /* This is the optimal IO size (for stat), not the fs block size */
 986         inode->i_blocks = 0;
 987         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
 988                                                        ext4_current_time(inode);
 989
 990         memset(ei->i_data, 0, sizeof(ei->i_data));
 991         ei->i_dir_start_lookup = 0;
 992         ei->i_disksize = 0;
 993
 994         /*
 995          * Don't inherit extent flag from directory, amongst others. We set
 996          * extent flag on newly created directory and file only if -o extent
 997          * mount option is specified
 998          */
 999         ei->i_flags =
1000                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1001         ei->i_file_acl = 0;
1002         ei->i_dtime = 0;
1003         ei->i_block_group = group;
1004         ei->i_last_alloc_group = ~0;
1005
1006         ext4_set_inode_flags(inode);
1007         if (IS_DIRSYNC(inode))
1008                 ext4_handle_sync(handle);
1009         if (insert_inode_locked(inode) < 0) {
1010                 err = -EINVAL;
1011                 goto fail_drop;
1012         }
1013         spin_lock(&sbi->s_next_gen_lock);
1014         inode->i_generation = sbi->s_next_generation++;
1015         spin_unlock(&sbi->s_next_gen_lock);
1016
1017         ei->i_state = EXT4_STATE_NEW;
1018
1019         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
1020
1021         ret = inode;
1022         if (vfs_dq_alloc_inode(inode)) {
1023                 err = -EDQUOT;
1024                 goto fail_drop;
1025         }
1026
1027         err = ext4_init_acl(handle, inode, dir);
1028         if (err)
1029                 goto fail_free_drop;
1030
1031         err = ext4_init_security(handle, inode, dir);
1032         if (err)
1033                 goto fail_free_drop;
1034
1035         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
1036                 /* set extent flag only for directory, file and normal symlink*/
1037                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1038                         EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;
1039                         ext4_ext_tree_init(handle, inode);
1040                 }
1041         }
1042
1043         err = ext4_mark_inode_dirty(handle, inode);
1044         if (err) {
1045                 ext4_std_error(sb, err);
1046                 goto fail_free_drop;
1047         }
1048
1049         ext4_debug("allocating inode %lu\n", inode->i_ino);
1050         trace_mark(ext4_allocate_inode, "dev %s ino %lu dir %lu mode %d",
1051                    sb->s_id, inode->i_ino, dir->i_ino, mode);
1052         goto really_out;
1053 fail:
1054         ext4_std_error(sb, err);
1055 out:
1056         iput(inode);
1057         ret = ERR_PTR(err);
1058 really_out:
1059         brelse(inode_bitmap_bh);
1060         return ret;
1061
1062 fail_free_drop:
1063         vfs_dq_free_inode(inode);
1064
1065 fail_drop:
1066         vfs_dq_drop(inode);
1067         inode->i_flags |= S_NOQUOTA;
1068         inode->i_nlink = 0;
1069         unlock_new_inode(inode);
1070         iput(inode);
1071         brelse(inode_bitmap_bh);
1072         return ERR_PTR(err);
1073 }
1074
1075 /* Verify that we are loading a valid orphan from disk */
1076 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1077 {
1078         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1079         ext4_group_t block_group;
1080         int bit;
1081         struct buffer_head *bitmap_bh;
1082         struct inode *inode = NULL;
1083         long err = -EIO;
1084
1085         /* Error cases - e2fsck has already cleaned up for us */
1086         if (ino > max_ino) {
1087                 ext4_warning(sb, __func__,
1088                              "bad orphan ino %lu!  e2fsck was run?", ino);
1089                 goto error;
1090         }
1091
1092         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1093         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1094         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1095         if (!bitmap_bh) {
1096                 ext4_warning(sb, __func__,
1097                              "inode bitmap error for orphan %lu", ino);
1098                 goto error;
1099         }
1100
1101         /* Having the inode bit set should be a 100% indicator that this
1102          * is a valid orphan (no e2fsck run on fs).  Orphans also include
1103          * inodes that were being truncated, so we can't check i_nlink==0.
1104          */
1105         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1106                 goto bad_orphan;
1107
1108         inode = ext4_iget(sb, ino);
1109         if (IS_ERR(inode))
1110                 goto iget_failed;
1111
1112         /*
1113          * If the orphans has i_nlinks > 0 then it should be able to be
1114          * truncated, otherwise it won't be removed from the orphan list
1115          * during processing and an infinite loop will result.
1116          */
1117         if (inode->i_nlink && !ext4_can_truncate(inode))
1118                 goto bad_orphan;
1119
1120         if (NEXT_ORPHAN(inode) > max_ino)
1121                 goto bad_orphan;
1122         brelse(bitmap_bh);
1123         return inode;
1124
1125 iget_failed:
1126         err = PTR_ERR(inode);
1127         inode = NULL;
1128 bad_orphan:
1129         ext4_warning(sb, __func__,
1130                      "bad orphan inode %lu!  e2fsck was run?", ino);
1131         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1132                bit, (unsigned long long)bitmap_bh->b_blocknr,
1133                ext4_test_bit(bit, bitmap_bh->b_data));
1134         printk(KERN_NOTICE "inode=%p\n", inode);
1135         if (inode) {
1136                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
1137                        is_bad_inode(inode));
1138                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
1139                        NEXT_ORPHAN(inode));
1140                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
1141                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
1142                 /* Avoid freeing blocks if we got a bad deleted inode */
1143                 if (inode->i_nlink == 0)
1144                         inode->i_blocks = 0;
1145                 iput(inode);
1146         }
1147         brelse(bitmap_bh);
1148 error:
1149         return ERR_PTR(err);
1150 }
1151
1152 unsigned long ext4_count_free_inodes(struct super_block *sb)
1153 {
1154         unsigned long desc_count;
1155         struct ext4_group_desc *gdp;
1156         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1157 #ifdef EXT4FS_DEBUG
1158         struct ext4_super_block *es;
1159         unsigned long bitmap_count, x;
1160         struct buffer_head *bitmap_bh = NULL;
1161
1162         es = EXT4_SB(sb)->s_es;
1163         desc_count = 0;
1164         bitmap_count = 0;
1165         gdp = NULL;
1166         for (i = 0; i < ngroups; i++) {
1167                 gdp = ext4_get_group_desc(sb, i, NULL);
1168                 if (!gdp)
1169                         continue;
1170                 desc_count += ext4_free_inodes_count(sb, gdp);
1171                 brelse(bitmap_bh);
1172                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1173                 if (!bitmap_bh)
1174                         continue;
1175
1176                 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
1177                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1178                         i, ext4_free_inodes_count(sb, gdp), x);
1179                 bitmap_count += x;
1180         }
1181         brelse(bitmap_bh);
1182         printk(KERN_DEBUG "ext4_count_free_inodes: "
1183                "stored = %u, computed = %lu, %lu\n",
1184                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1185         return desc_count;
1186 #else
1187         desc_count = 0;
1188         for (i = 0; i < ngroups; i++) {
1189                 gdp = ext4_get_group_desc(sb, i, NULL);
1190                 if (!gdp)
1191                         continue;
1192                 desc_count += ext4_free_inodes_count(sb, gdp);
1193                 cond_resched();
1194         }
1195         return desc_count;
1196 #endif
1197 }
1198
1199 /* Called at mount-time, super-block is locked */
1200 unsigned long ext4_count_dirs(struct super_block * sb)
1201 {
1202         unsigned long count = 0;
1203         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1204
1205         for (i = 0; i < ngroups; i++) {
1206                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1207                 if (!gdp)
1208                         continue;
1209                 count += ext4_used_dirs_count(sb, gdp);
1210         }
1211         return count;
1212 }