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 ext4_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 static unsigned ext4_init_inode_bitmap(struct super_block *sb,
  69                                        struct buffer_head *bh,
  70                                        ext4_group_t block_group,
  71                                        struct ext4_group_desc *gdp)
  72 {
  73         struct ext4_sb_info *sbi = EXT4_SB(sb);
  74
  75         J_ASSERT_BH(bh, buffer_locked(bh));
  76
  77         /* If checksum is bad mark all blocks and inodes use to prevent
  78          * allocation, essentially implementing a per-group read-only flag. */
  79         if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
  80                 ext4_error(sb, "Checksum bad for group %u", block_group);
  81                 ext4_free_blks_set(sb, gdp, 0);
  82                 ext4_free_inodes_set(sb, gdp, 0);
  83                 ext4_itable_unused_set(sb, gdp, 0);
  84                 memset(bh->b_data, 0xff, sb->s_blocksize);
  85                 return 0;
  86         }
  87
  88         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
  89         ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
  90                         bh->b_data);
  91
  92         return EXT4_INODES_PER_GROUP(sb);
  93 }
  94
  95 /*
  96  * Read the inode allocation bitmap for a given block_group, reading
  97  * into the specified slot in the superblock's bitmap cache.
  98  *
  99  * Return buffer_head of bitmap on success or NULL.
 100  */
 101 static struct buffer_head *
 102 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 103 {
 104         struct ext4_group_desc *desc;
 105         struct buffer_head *bh = NULL;
 106         ext4_fsblk_t bitmap_blk;
 107
 108         desc = ext4_get_group_desc(sb, block_group, NULL);
 109         if (!desc)
 110                 return NULL;
 111
 112         bitmap_blk = ext4_inode_bitmap(sb, desc);
 113         bh = sb_getblk(sb, bitmap_blk);
 114         if (unlikely(!bh)) {
 115                 ext4_error(sb, "Cannot read inode bitmap - "
 116                             "block_group = %u, inode_bitmap = %llu",
 117                             block_group, bitmap_blk);
 118                 return NULL;
 119         }
 120         if (bitmap_uptodate(bh))
 121                 return bh;
 122
 123         lock_buffer(bh);
 124         if (bitmap_uptodate(bh)) {
 125                 unlock_buffer(bh);
 126                 return bh;
 127         }
 128
 129         ext4_lock_group(sb, block_group);
 130         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 131                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
 132                 set_bitmap_uptodate(bh);
 133                 set_buffer_uptodate(bh);
 134                 ext4_unlock_group(sb, block_group);
 135                 unlock_buffer(bh);
 136                 return bh;
 137         }
 138         ext4_unlock_group(sb, block_group);
 139
 140         if (buffer_uptodate(bh)) {
 141                 /*
 142                  * if not uninit if bh is uptodate,
 143                  * bitmap is also uptodate
 144                  */
 145                 set_bitmap_uptodate(bh);
 146                 unlock_buffer(bh);
 147                 return bh;
 148         }
 149         /*
 150          * submit the buffer_head for read. We can
 151          * safely mark the bitmap as uptodate now.
 152          * We do it here so the bitmap uptodate bit
 153          * get set with buffer lock held.
 154          */
 155         trace_ext4_load_inode_bitmap(sb, block_group);
 156         set_bitmap_uptodate(bh);
 157         if (bh_submit_read(bh) < 0) {
 158                 put_bh(bh);
 159                 ext4_error(sb, "Cannot read inode bitmap - "
 160                             "block_group = %u, inode_bitmap = %llu",
 161                             block_group, bitmap_blk);
 162                 return NULL;
 163         }
 164         return bh;
 165 }
 166
 167 /*
 168  * NOTE! When we get the inode, we're the only people
 169  * that have access to it, and as such there are no
 170  * race conditions we have to worry about. The inode
 171  * is not on the hash-lists, and it cannot be reached
 172  * through the filesystem because the directory entry
 173  * has been deleted earlier.
 174  *
 175  * HOWEVER: we must make sure that we get no aliases,
 176  * which means that we have to call "clear_inode()"
 177  * _before_ we mark the inode not in use in the inode
 178  * bitmaps. Otherwise a newly created file might use
 179  * the same inode number (not actually the same pointer
 180  * though), and then we'd have two inodes sharing the
 181  * same inode number and space on the harddisk.
 182  */
 183 void ext4_free_inode(handle_t *handle, struct inode *inode)
 184 {
 185         struct super_block *sb = inode->i_sb;
 186         int is_directory;
 187         unsigned long ino;
 188         struct buffer_head *bitmap_bh = NULL;
 189         struct buffer_head *bh2;
 190         ext4_group_t block_group;
 191         unsigned long bit;
 192         struct ext4_group_desc *gdp;
 193         struct ext4_super_block *es;
 194         struct ext4_sb_info *sbi;
 195         int fatal = 0, err, count, cleared;
 196
 197         if (atomic_read(&inode->i_count) > 1) {
 198                 printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
 199                        atomic_read(&inode->i_count));
 200                 return;
 201         }
 202         if (inode->i_nlink) {
 203                 printk(KERN_ERR "ext4_free_inode: inode has nlink=%d\n",
 204                        inode->i_nlink);
 205                 return;
 206         }
 207         if (!sb) {
 208                 printk(KERN_ERR "ext4_free_inode: inode on "
 209                        "nonexistent device\n");
 210                 return;
 211         }
 212         sbi = EXT4_SB(sb);
 213
 214         ino = inode->i_ino;
 215         ext4_debug("freeing inode %lu\n", ino);
 216         trace_ext4_free_inode(inode);
 217
 218         /*
 219          * Note: we must free any quota before locking the superblock,
 220          * as writing the quota to disk may need the lock as well.
 221          */
 222         dquot_initialize(inode);
 223         ext4_xattr_delete_inode(handle, inode);
 224         dquot_free_inode(inode);
 225         dquot_drop(inode);
 226
 227         is_directory = S_ISDIR(inode->i_mode);
 228
 229         /* Do this BEFORE marking the inode not in use or returning an error */
 230         ext4_clear_inode(inode);
 231
 232         es = EXT4_SB(sb)->s_es;
 233         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 234                 ext4_error(sb, "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         fatal = -ESRCH;
 249         gdp = ext4_get_group_desc(sb, block_group, &bh2);
 250         if (gdp) {
 251                 BUFFER_TRACE(bh2, "get_write_access");
 252                 fatal = ext4_journal_get_write_access(handle, bh2);
 253         }
 254         ext4_lock_group(sb, block_group);
 255         cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
 256         if (fatal || !cleared) {
 257                 ext4_unlock_group(sb, block_group);
 258                 goto out;
 259         }
 260
 261         count = ext4_free_inodes_count(sb, gdp) + 1;
 262         ext4_free_inodes_set(sb, gdp, count);
 263         if (is_directory) {
 264                 count = ext4_used_dirs_count(sb, gdp) - 1;
 265                 ext4_used_dirs_set(sb, gdp, count);
 266                 percpu_counter_dec(&sbi->s_dirs_counter);
 267         }
 268         gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
 269         ext4_unlock_group(sb, block_group);
 270
 271         percpu_counter_inc(&sbi->s_freeinodes_counter);
 272         if (sbi->s_log_groups_per_flex) {
 273                 ext4_group_t f = ext4_flex_group(sbi, block_group);
 274
 275                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 276                 if (is_directory)
 277                         atomic_dec(&sbi->s_flex_groups[f].used_dirs);
 278         }
 279         BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 280         fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
 281 out:
 282         if (cleared) {
 283                 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 284                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 285                 if (!fatal)
 286                         fatal = err;
 287                 ext4_mark_super_dirty(sb);
 288         } else
 289                 ext4_error(sb, "bit already cleared for inode %lu", ino);
 290
 291 error_return:
 292         brelse(bitmap_bh);
 293         ext4_std_error(sb, fatal);
 294 }
 295
 296 /*
 297  * There are two policies for allocating an inode.  If the new inode is
 298  * a directory, then a forward search is made for a block group with both
 299  * free space and a low directory-to-inode ratio; if that fails, then of
 300  * the groups with above-average free space, that group with the fewest
 301  * directories already is chosen.
 302  *
 303  * For other inodes, search forward from the parent directory\'s block
 304  * group to find a free inode.
 305  */
 306 static int find_group_dir(struct super_block *sb, struct inode *parent,
 307                                 ext4_group_t *best_group)
 308 {
 309         ext4_group_t ngroups = ext4_get_groups_count(sb);
 310         unsigned int freei, avefreei;
 311         struct ext4_group_desc *desc, *best_desc = NULL;
 312         ext4_group_t group;
 313         int ret = -1;
 314
 315         freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
 316         avefreei = freei / ngroups;
 317
 318         for (group = 0; group < ngroups; group++) {
 319                 desc = ext4_get_group_desc(sb, group, NULL);
 320                 if (!desc || !ext4_free_inodes_count(sb, desc))
 321                         continue;
 322                 if (ext4_free_inodes_count(sb, desc) < avefreei)
 323                         continue;
 324                 if (!best_desc ||
 325                     (ext4_free_blks_count(sb, desc) >
 326                      ext4_free_blks_count(sb, best_desc))) {
 327                         *best_group = group;
 328                         best_desc = desc;
 329                         ret = 0;
 330                 }
 331         }
 332         return ret;
 333 }
 334
 335 #define free_block_ratio 10
 336
 337 static int find_group_flex(struct super_block *sb, struct inode *parent,
 338                            ext4_group_t *best_group)
 339 {
 340         struct ext4_sb_info *sbi = EXT4_SB(sb);
 341         struct ext4_group_desc *desc;
 342         struct flex_groups *flex_group = sbi->s_flex_groups;
 343         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 344         ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
 345         ext4_group_t ngroups = ext4_get_groups_count(sb);
 346         int flex_size = ext4_flex_bg_size(sbi);
 347         ext4_group_t best_flex = parent_fbg_group;
 348         int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
 349         int flexbg_free_blocks;
 350         int flex_freeb_ratio;
 351         ext4_group_t n_fbg_groups;
 352         ext4_group_t i;
 353
 354         n_fbg_groups = (ngroups + flex_size - 1) >>
 355                 sbi->s_log_groups_per_flex;
 356
 357 find_close_to_parent:
 358         flexbg_free_blocks = atomic_read(&flex_group[best_flex].free_blocks);
 359         flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 360         if (atomic_read(&flex_group[best_flex].free_inodes) &&
 361             flex_freeb_ratio > free_block_ratio)
 362                 goto found_flexbg;
 363
 364         if (best_flex && best_flex == parent_fbg_group) {
 365                 best_flex--;
 366                 goto find_close_to_parent;
 367         }
 368
 369         for (i = 0; i < n_fbg_groups; i++) {
 370                 if (i == parent_fbg_group || i == parent_fbg_group - 1)
 371                         continue;
 372
 373                 flexbg_free_blocks = atomic_read(&flex_group[i].free_blocks);
 374                 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 375
 376                 if (flex_freeb_ratio > free_block_ratio &&
 377                     (atomic_read(&flex_group[i].free_inodes))) {
 378                         best_flex = i;
 379                         goto found_flexbg;
 380                 }
 381
 382                 if ((atomic_read(&flex_group[best_flex].free_inodes) == 0) ||
 383                     ((atomic_read(&flex_group[i].free_blocks) >
 384                       atomic_read(&flex_group[best_flex].free_blocks)) &&
 385                      atomic_read(&flex_group[i].free_inodes)))
 386                         best_flex = i;
 387         }
 388
 389         if (!atomic_read(&flex_group[best_flex].free_inodes) ||
 390             !atomic_read(&flex_group[best_flex].free_blocks))
 391                 return -1;
 392
 393 found_flexbg:
 394         for (i = best_flex * flex_size; i < ngroups &&
 395                      i < (best_flex + 1) * flex_size; i++) {
 396                 desc = ext4_get_group_desc(sb, i, NULL);
 397                 if (ext4_free_inodes_count(sb, desc)) {
 398                         *best_group = i;
 399                         goto out;
 400                 }
 401         }
 402
 403         return -1;
 404 out:
 405         return 0;
 406 }
 407
 408 struct orlov_stats {
 409         __u32 free_inodes;
 410         __u32 free_blocks;
 411         __u32 used_dirs;
 412 };
 413
 414 /*
 415  * Helper function for Orlov's allocator; returns critical information
 416  * for a particular block group or flex_bg.  If flex_size is 1, then g
 417  * is a block group number; otherwise it is flex_bg number.
 418  */
 419 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 420                             int flex_size, struct orlov_stats *stats)
 421 {
 422         struct ext4_group_desc *desc;
 423         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
 424
 425         if (flex_size > 1) {
 426                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
 427                 stats->free_blocks = atomic_read(&flex_group[g].free_blocks);
 428                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
 429                 return;
 430         }
 431
 432         desc = ext4_get_group_desc(sb, g, NULL);
 433         if (desc) {
 434                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
 435                 stats->free_blocks = ext4_free_blks_count(sb, desc);
 436                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
 437         } else {
 438                 stats->free_inodes = 0;
 439                 stats->free_blocks = 0;
 440                 stats->used_dirs = 0;
 441         }
 442 }
 443
 444 /*
 445  * Orlov's allocator for directories.
 446  *
 447  * We always try to spread first-level directories.
 448  *
 449  * If there are blockgroups with both free inodes and free blocks counts
 450  * not worse than average we return one with smallest directory count.
 451  * Otherwise we simply return a random group.
 452  *
 453  * For the rest rules look so:
 454  *
 455  * It's OK to put directory into a group unless
 456  * it has too many directories already (max_dirs) or
 457  * it has too few free inodes left (min_inodes) or
 458  * it has too few free blocks left (min_blocks) or
 459  * Parent's group is preferred, if it doesn't satisfy these
 460  * conditions we search cyclically through the rest. If none
 461  * of the groups look good we just look for a group with more
 462  * free inodes than average (starting at parent's group).
 463  */
 464
 465 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 466                             ext4_group_t *group, int mode,
 467                             const struct qstr *qstr)
 468 {
 469         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 470         struct ext4_sb_info *sbi = EXT4_SB(sb);
 471         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 472         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 473         unsigned int freei, avefreei;
 474         ext4_fsblk_t freeb, avefreeb;
 475         unsigned int ndirs;
 476         int max_dirs, min_inodes;
 477         ext4_grpblk_t min_blocks;
 478         ext4_group_t i, grp, g, ngroups;
 479         struct ext4_group_desc *desc;
 480         struct orlov_stats stats;
 481         int flex_size = ext4_flex_bg_size(sbi);
 482         struct dx_hash_info hinfo;
 483
 484         ngroups = real_ngroups;
 485         if (flex_size > 1) {
 486                 ngroups = (real_ngroups + flex_size - 1) >>
 487                         sbi->s_log_groups_per_flex;
 488                 parent_group >>= sbi->s_log_groups_per_flex;
 489         }
 490
 491         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 492         avefreei = freei / ngroups;
 493         freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 494         avefreeb = freeb;
 495         do_div(avefreeb, ngroups);
 496         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 497
 498         if (S_ISDIR(mode) &&
 499             ((parent == sb->s_root->d_inode) ||
 500              (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
 501                 int best_ndir = inodes_per_group;
 502                 int ret = -1;
 503
 504                 if (qstr) {
 505                         hinfo.hash_version = DX_HASH_HALF_MD4;
 506                         hinfo.seed = sbi->s_hash_seed;
 507                         ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
 508                         grp = hinfo.hash;
 509                 } else
 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, NULL);
 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_info *grp = ext4_get_group_info(sb, group);
 721         struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
 722
 723         /*
 724          * We have to be sure that new inode allocation does not race with
 725          * inode table initialization, because otherwise we may end up
 726          * allocating and writing new inode right before sb_issue_zeroout
 727          * takes place and overwriting our new inode with zeroes. So we
 728          * take alloc_sem to prevent it.
 729          */
 730         down_read(&grp->alloc_sem);
 731         ext4_lock_group(sb, group);
 732         if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
 733                 /* not a free inode */
 734                 retval = 1;
 735                 goto err_ret;
 736         }
 737         ino++;
 738         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
 739                         ino > EXT4_INODES_PER_GROUP(sb)) {
 740                 ext4_unlock_group(sb, group);
 741                 up_read(&grp->alloc_sem);
 742                 ext4_error(sb, "reserved inode or inode > inodes count - "
 743                            "block_group = %u, inode=%lu", group,
 744                            ino + group * EXT4_INODES_PER_GROUP(sb));
 745                 return 1;
 746         }
 747         /* If we didn't allocate from within the initialized part of the inode
 748          * table then we need to initialize up to this inode. */
 749         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 750
 751                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 752                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 753                         /* When marking the block group with
 754                          * ~EXT4_BG_INODE_UNINIT we don't want to depend
 755                          * on the value of bg_itable_unused even though
 756                          * mke2fs could have initialized the same for us.
 757                          * Instead we calculated the value below
 758                          */
 759
 760                         free = 0;
 761                 } else {
 762                         free = EXT4_INODES_PER_GROUP(sb) -
 763                                 ext4_itable_unused_count(sb, gdp);
 764                 }
 765
 766                 /*
 767                  * Check the relative inode number against the last used
 768                  * relative inode number in this group. if it is greater
 769                  * we need to  update the bg_itable_unused count
 770                  *
 771                  */
 772                 if (ino > free)
 773                         ext4_itable_unused_set(sb, gdp,
 774                                         (EXT4_INODES_PER_GROUP(sb) - ino));
 775         }
 776         count = ext4_free_inodes_count(sb, gdp) - 1;
 777         ext4_free_inodes_set(sb, gdp, count);
 778         if (S_ISDIR(mode)) {
 779                 count = ext4_used_dirs_count(sb, gdp) + 1;
 780                 ext4_used_dirs_set(sb, gdp, count);
 781                 if (sbi->s_log_groups_per_flex) {
 782                         ext4_group_t f = ext4_flex_group(sbi, group);
 783
 784                         atomic_inc(&sbi->s_flex_groups[f].used_dirs);
 785                 }
 786         }
 787         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
 788 err_ret:
 789         ext4_unlock_group(sb, group);
 790         up_read(&grp->alloc_sem);
 791         return retval;
 792 }
 793
 794 /*
 795  * There are two policies for allocating an inode.  If the new inode is
 796  * a directory, then a forward search is made for a block group with both
 797  * free space and a low directory-to-inode ratio; if that fails, then of
 798  * the groups with above-average free space, that group with the fewest
 799  * directories already is chosen.
 800  *
 801  * For other inodes, search forward from the parent directory's block
 802  * group to find a free inode.
 803  */
 804 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode,
 805                              const struct qstr *qstr, __u32 goal)
 806 {
 807         struct super_block *sb;
 808         struct buffer_head *inode_bitmap_bh = NULL;
 809         struct buffer_head *group_desc_bh;
 810         ext4_group_t ngroups, group = 0;
 811         unsigned long ino = 0;
 812         struct inode *inode;
 813         struct ext4_group_desc *gdp = NULL;
 814         struct ext4_inode_info *ei;
 815         struct ext4_sb_info *sbi;
 816         int ret2, err = 0;
 817         struct inode *ret;
 818         ext4_group_t i;
 819         int free = 0;
 820         static int once = 1;
 821         ext4_group_t flex_group;
 822
 823         /* Cannot create files in a deleted directory */
 824         if (!dir || !dir->i_nlink)
 825                 return ERR_PTR(-EPERM);
 826
 827         sb = dir->i_sb;
 828         ngroups = ext4_get_groups_count(sb);
 829         trace_ext4_request_inode(dir, mode);
 830         inode = new_inode(sb);
 831         if (!inode)
 832                 return ERR_PTR(-ENOMEM);
 833         ei = EXT4_I(inode);
 834         sbi = EXT4_SB(sb);
 835
 836         if (!goal)
 837                 goal = sbi->s_inode_goal;
 838
 839         if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
 840                 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
 841                 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
 842                 ret2 = 0;
 843                 goto got_group;
 844         }
 845
 846         if (sbi->s_log_groups_per_flex && test_opt(sb, OLDALLOC)) {
 847                 ret2 = find_group_flex(sb, dir, &group);
 848                 if (ret2 == -1) {
 849                         ret2 = find_group_other(sb, dir, &group, mode);
 850                         if (ret2 == 0 && once) {
 851                                 once = 0;
 852                                 printk(KERN_NOTICE "ext4: find_group_flex "
 853                                        "failed, fallback succeeded dir %lu\n",
 854                                        dir->i_ino);
 855                         }
 856                 }
 857                 goto got_group;
 858         }
 859
 860         if (S_ISDIR(mode)) {
 861                 if (test_opt(sb, OLDALLOC))
 862                         ret2 = find_group_dir(sb, dir, &group);
 863                 else
 864                         ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
 865         } else
 866                 ret2 = find_group_other(sb, dir, &group, mode);
 867
 868 got_group:
 869         EXT4_I(dir)->i_last_alloc_group = group;
 870         err = -ENOSPC;
 871         if (ret2 == -1)
 872                 goto out;
 873
 874         for (i = 0; i < ngroups; i++, ino = 0) {
 875                 err = -EIO;
 876
 877                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 878                 if (!gdp)
 879                         goto fail;
 880
 881                 brelse(inode_bitmap_bh);
 882                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 883                 if (!inode_bitmap_bh)
 884                         goto fail;
 885
 886 repeat_in_this_group:
 887                 ino = ext4_find_next_zero_bit((unsigned long *)
 888                                               inode_bitmap_bh->b_data,
 889                                               EXT4_INODES_PER_GROUP(sb), ino);
 890
 891                 if (ino < EXT4_INODES_PER_GROUP(sb)) {
 892
 893                         BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 894                         err = ext4_journal_get_write_access(handle,
 895                                                             inode_bitmap_bh);
 896                         if (err)
 897                                 goto fail;
 898
 899                         BUFFER_TRACE(group_desc_bh, "get_write_access");
 900                         err = ext4_journal_get_write_access(handle,
 901                                                                 group_desc_bh);
 902                         if (err)
 903                                 goto fail;
 904                         if (!ext4_claim_inode(sb, inode_bitmap_bh,
 905                                                 ino, group, mode)) {
 906                                 /* we won it */
 907                                 BUFFER_TRACE(inode_bitmap_bh,
 908                                         "call ext4_handle_dirty_metadata");
 909                                 err = ext4_handle_dirty_metadata(handle,
 910                                                                  NULL,
 911                                                         inode_bitmap_bh);
 912                                 if (err)
 913                                         goto fail;
 914                                 /* zero bit is inode number 1*/
 915                                 ino++;
 916                                 goto got;
 917                         }
 918                         /* we lost it */
 919                         ext4_handle_release_buffer(handle, inode_bitmap_bh);
 920                         ext4_handle_release_buffer(handle, group_desc_bh);
 921
 922                         if (++ino < EXT4_INODES_PER_GROUP(sb))
 923                                 goto repeat_in_this_group;
 924                 }
 925
 926                 /*
 927                  * This case is possible in concurrent environment.  It is very
 928                  * rare.  We cannot repeat the find_group_xxx() call because
 929                  * that will simply return the same blockgroup, because the
 930                  * group descriptor metadata has not yet been updated.
 931                  * So we just go onto the next blockgroup.
 932                  */
 933                 if (++group == ngroups)
 934                         group = 0;
 935         }
 936         err = -ENOSPC;
 937         goto out;
 938
 939 got:
 940         /* We may have to initialize the block bitmap if it isn't already */
 941         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
 942             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 943                 struct buffer_head *block_bitmap_bh;
 944
 945                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 946                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 947                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 948                 if (err) {
 949                         brelse(block_bitmap_bh);
 950                         goto fail;
 951                 }
 952
 953                 free = 0;
 954                 ext4_lock_group(sb, group);
 955                 /* recheck and clear flag under lock if we still need to */
 956                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 957                         free = ext4_free_blocks_after_init(sb, group, gdp);
 958                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 959                         ext4_free_blks_set(sb, gdp, free);
 960                         gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
 961                                                                 gdp);
 962                 }
 963                 ext4_unlock_group(sb, group);
 964
 965                 /* Don't need to dirty bitmap block if we didn't change it */
 966                 if (free) {
 967                         BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
 968                         err = ext4_handle_dirty_metadata(handle,
 969                                                         NULL, block_bitmap_bh);
 970                 }
 971
 972                 brelse(block_bitmap_bh);
 973                 if (err)
 974                         goto fail;
 975         }
 976         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
 977         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
 978         if (err)
 979                 goto fail;
 980
 981         percpu_counter_dec(&sbi->s_freeinodes_counter);
 982         if (S_ISDIR(mode))
 983                 percpu_counter_inc(&sbi->s_dirs_counter);
 984         ext4_mark_super_dirty(sb);
 985
 986         if (sbi->s_log_groups_per_flex) {
 987                 flex_group = ext4_flex_group(sbi, group);
 988                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
 989         }
 990
 991         if (test_opt(sb, GRPID)) {
 992                 inode->i_mode = mode;
 993                 inode->i_uid = current_fsuid();
 994                 inode->i_gid = dir->i_gid;
 995         } else
 996                 inode_init_owner(inode, dir, mode);
 997
 998         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
 999         /* This is the optimal IO size (for stat), not the fs block size */
1000         inode->i_blocks = 0;
1001         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
1002                                                        ext4_current_time(inode);
1003
1004         memset(ei->i_data, 0, sizeof(ei->i_data));
1005         ei->i_dir_start_lookup = 0;
1006         ei->i_disksize = 0;
1007
1008         /*
1009          * Don't inherit extent flag from directory, amongst others. We set
1010          * extent flag on newly created directory and file only if -o extent
1011          * mount option is specified
1012          */
1013         ei->i_flags =
1014                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1015         ei->i_file_acl = 0;
1016         ei->i_dtime = 0;
1017         ei->i_block_group = group;
1018         ei->i_last_alloc_group = ~0;
1019
1020         ext4_set_inode_flags(inode);
1021         if (IS_DIRSYNC(inode))
1022                 ext4_handle_sync(handle);
1023         if (insert_inode_locked(inode) < 0) {
1024                 err = -EINVAL;
1025                 goto fail_drop;
1026         }
1027         spin_lock(&sbi->s_next_gen_lock);
1028         inode->i_generation = sbi->s_next_generation++;
1029         spin_unlock(&sbi->s_next_gen_lock);
1030
1031         ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1032         ext4_set_inode_state(inode, EXT4_STATE_NEW);
1033
1034         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
1035
1036         ret = inode;
1037         dquot_initialize(inode);
1038         err = dquot_alloc_inode(inode);
1039         if (err)
1040                 goto fail_drop;
1041
1042         err = ext4_init_acl(handle, inode, dir);
1043         if (err)
1044                 goto fail_free_drop;
1045
1046         err = ext4_init_security(handle, inode, dir, qstr);
1047         if (err)
1048                 goto fail_free_drop;
1049
1050         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
1051                 /* set extent flag only for directory, file and normal symlink*/
1052                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1053                         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1054                         ext4_ext_tree_init(handle, inode);
1055                 }
1056         }
1057
1058         if (ext4_handle_valid(handle)) {
1059                 ei->i_sync_tid = handle->h_transaction->t_tid;
1060                 ei->i_datasync_tid = handle->h_transaction->t_tid;
1061         }
1062
1063         err = ext4_mark_inode_dirty(handle, inode);
1064         if (err) {
1065                 ext4_std_error(sb, err);
1066                 goto fail_free_drop;
1067         }
1068
1069         ext4_debug("allocating inode %lu\n", inode->i_ino);
1070         trace_ext4_allocate_inode(inode, dir, mode);
1071         goto really_out;
1072 fail:
1073         ext4_std_error(sb, err);
1074 out:
1075         iput(inode);
1076         ret = ERR_PTR(err);
1077 really_out:
1078         brelse(inode_bitmap_bh);
1079         return ret;
1080
1081 fail_free_drop:
1082         dquot_free_inode(inode);
1083
1084 fail_drop:
1085         dquot_drop(inode);
1086         inode->i_flags |= S_NOQUOTA;
1087         inode->i_nlink = 0;
1088         unlock_new_inode(inode);
1089         iput(inode);
1090         brelse(inode_bitmap_bh);
1091         return ERR_PTR(err);
1092 }
1093
1094 /* Verify that we are loading a valid orphan from disk */
1095 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1096 {
1097         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1098         ext4_group_t block_group;
1099         int bit;
1100         struct buffer_head *bitmap_bh;
1101         struct inode *inode = NULL;
1102         long err = -EIO;
1103
1104         /* Error cases - e2fsck has already cleaned up for us */
1105         if (ino > max_ino) {
1106                 ext4_warning(sb, "bad orphan ino %lu!  e2fsck was run?", ino);
1107                 goto error;
1108         }
1109
1110         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1111         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1112         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1113         if (!bitmap_bh) {
1114                 ext4_warning(sb, "inode bitmap error for orphan %lu", ino);
1115                 goto error;
1116         }
1117
1118         /* Having the inode bit set should be a 100% indicator that this
1119          * is a valid orphan (no e2fsck run on fs).  Orphans also include
1120          * inodes that were being truncated, so we can't check i_nlink==0.
1121          */
1122         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1123                 goto bad_orphan;
1124
1125         inode = ext4_iget(sb, ino);
1126         if (IS_ERR(inode))
1127                 goto iget_failed;
1128
1129         /*
1130          * If the orphans has i_nlinks > 0 then it should be able to be
1131          * truncated, otherwise it won't be removed from the orphan list
1132          * during processing and an infinite loop will result.
1133          */
1134         if (inode->i_nlink && !ext4_can_truncate(inode))
1135                 goto bad_orphan;
1136
1137         if (NEXT_ORPHAN(inode) > max_ino)
1138                 goto bad_orphan;
1139         brelse(bitmap_bh);
1140         return inode;
1141
1142 iget_failed:
1143         err = PTR_ERR(inode);
1144         inode = NULL;
1145 bad_orphan:
1146         ext4_warning(sb, "bad orphan inode %lu!  e2fsck was run?", ino);
1147         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1148                bit, (unsigned long long)bitmap_bh->b_blocknr,
1149                ext4_test_bit(bit, bitmap_bh->b_data));
1150         printk(KERN_NOTICE "inode=%p\n", inode);
1151         if (inode) {
1152                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
1153                        is_bad_inode(inode));
1154                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
1155                        NEXT_ORPHAN(inode));
1156                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
1157                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
1158                 /* Avoid freeing blocks if we got a bad deleted inode */
1159                 if (inode->i_nlink == 0)
1160                         inode->i_blocks = 0;
1161                 iput(inode);
1162         }
1163         brelse(bitmap_bh);
1164 error:
1165         return ERR_PTR(err);
1166 }
1167
1168 unsigned long ext4_count_free_inodes(struct super_block *sb)
1169 {
1170         unsigned long desc_count;
1171         struct ext4_group_desc *gdp;
1172         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1173 #ifdef EXT4FS_DEBUG
1174         struct ext4_super_block *es;
1175         unsigned long bitmap_count, x;
1176         struct buffer_head *bitmap_bh = NULL;
1177
1178         es = EXT4_SB(sb)->s_es;
1179         desc_count = 0;
1180         bitmap_count = 0;
1181         gdp = NULL;
1182         for (i = 0; i < ngroups; i++) {
1183                 gdp = ext4_get_group_desc(sb, i, NULL);
1184                 if (!gdp)
1185                         continue;
1186                 desc_count += ext4_free_inodes_count(sb, gdp);
1187                 brelse(bitmap_bh);
1188                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1189                 if (!bitmap_bh)
1190                         continue;
1191
1192                 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
1193                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1194                         (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1195                 bitmap_count += x;
1196         }
1197         brelse(bitmap_bh);
1198         printk(KERN_DEBUG "ext4_count_free_inodes: "
1199                "stored = %u, computed = %lu, %lu\n",
1200                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1201         return desc_count;
1202 #else
1203         desc_count = 0;
1204         for (i = 0; i < ngroups; i++) {
1205                 gdp = ext4_get_group_desc(sb, i, NULL);
1206                 if (!gdp)
1207                         continue;
1208                 desc_count += ext4_free_inodes_count(sb, gdp);
1209                 cond_resched();
1210         }
1211         return desc_count;
1212 #endif
1213 }
1214
1215 /* Called at mount-time, super-block is locked */
1216 unsigned long ext4_count_dirs(struct super_block * sb)
1217 {
1218         unsigned long count = 0;
1219         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1220
1221         for (i = 0; i < ngroups; i++) {
1222                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1223                 if (!gdp)
1224                         continue;
1225                 count += ext4_used_dirs_count(sb, gdp);
1226         }
1227         return count;
1228 }
1229
1230 /*
1231  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1232  * inode table. Must be called without any spinlock held. The only place
1233  * where it is called from on active part of filesystem is ext4lazyinit
1234  * thread, so we do not need any special locks, however we have to prevent
1235  * inode allocation from the current group, so we take alloc_sem lock, to
1236  * block ext4_claim_inode until we are finished.
1237  */
1238 extern int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1239                                  int barrier)
1240 {
1241         struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1242         struct ext4_sb_info *sbi = EXT4_SB(sb);
1243         struct ext4_group_desc *gdp = NULL;
1244         struct buffer_head *group_desc_bh;
1245         handle_t *handle;
1246         ext4_fsblk_t blk;
1247         int num, ret = 0, used_blks = 0;
1248
1249         /* This should not happen, but just to be sure check this */
1250         if (sb->s_flags & MS_RDONLY) {
1251                 ret = 1;
1252                 goto out;
1253         }
1254
1255         gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1256         if (!gdp)
1257                 goto out;
1258
1259         /*
1260          * We do not need to lock this, because we are the only one
1261          * handling this flag.
1262          */
1263         if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1264                 goto out;
1265
1266         handle = ext4_journal_start_sb(sb, 1);
1267         if (IS_ERR(handle)) {
1268                 ret = PTR_ERR(handle);
1269                 goto out;
1270         }
1271
1272         down_write(&grp->alloc_sem);
1273         /*
1274          * If inode bitmap was already initialized there may be some
1275          * used inodes so we need to skip blocks with used inodes in
1276          * inode table.
1277          */
1278         if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1279                 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1280                             ext4_itable_unused_count(sb, gdp)),
1281                             sbi->s_inodes_per_block);
1282
1283         if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1284                 ext4_error(sb, "Something is wrong with group %u\n"
1285                            "Used itable blocks: %d"
1286                            "itable unused count: %u\n",
1287                            group, used_blks,
1288                            ext4_itable_unused_count(sb, gdp));
1289                 ret = 1;
1290                 goto out;
1291         }
1292
1293         blk = ext4_inode_table(sb, gdp) + used_blks;
1294         num = sbi->s_itb_per_group - used_blks;
1295
1296         BUFFER_TRACE(group_desc_bh, "get_write_access");
1297         ret = ext4_journal_get_write_access(handle,
1298                                             group_desc_bh);
1299         if (ret)
1300                 goto err_out;
1301
1302         /*
1303          * Skip zeroout if the inode table is full. But we set the ZEROED
1304          * flag anyway, because obviously, when it is full it does not need
1305          * further zeroing.
1306          */
1307         if (unlikely(num == 0))
1308                 goto skip_zeroout;
1309
1310         ext4_debug("going to zero out inode table in group %d\n",
1311                    group);
1312         ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1313         if (ret < 0)
1314                 goto err_out;
1315         if (barrier)
1316                 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1317
1318 skip_zeroout:
1319         ext4_lock_group(sb, group);
1320         gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1321         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
1322         ext4_unlock_group(sb, group);
1323
1324         BUFFER_TRACE(group_desc_bh,
1325                      "call ext4_handle_dirty_metadata");
1326         ret = ext4_handle_dirty_metadata(handle, NULL,
1327                                          group_desc_bh);
1328
1329 err_out:
1330         up_write(&grp->alloc_sem);
1331         ext4_journal_stop(handle);
1332 out:
1333         return ret;
1334 }