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/stat.h>
  18 #include <linux/string.h>
  19 #include <linux/quotaops.h>
  20 #include <linux/buffer_head.h>
  21 #include <linux/random.h>
  22 #include <linux/bitops.h>
  23 #include <linux/blkdev.h>
  24 #include <asm/byteorder.h>
  25
  26 #include "ext4.h"
  27 #include "ext4_jbd2.h"
  28 #include "xattr.h"
  29 #include "acl.h"
  30
  31 #include <trace/events/ext4.h>
  32
  33 /*
  34  * ialloc.c contains the inodes allocation and deallocation routines
  35  */
  36
  37 /*
  38  * The free inodes are managed by bitmaps.  A file system contains several
  39  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  40  * block for inodes, N blocks for the inode table and data blocks.
  41  *
  42  * The file system contains group descriptors which are located after the
  43  * super block.  Each descriptor contains the number of the bitmap block and
  44  * the free blocks count in the block.
  45  */
  46
  47 /*
  48  * To avoid calling the atomic setbit hundreds or thousands of times, we only
  49  * need to use it within a single byte (to ensure we get endianness right).
  50  * We can use memset for the rest of the bitmap as there are no other users.
  51  */
  52 void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
  53 {
  54         int i;
  55
  56         if (start_bit >= end_bit)
  57                 return;
  58
  59         ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
  60         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
  61                 ext4_set_bit(i, bitmap);
  62         if (i < end_bit)
  63                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
  64 }
  65
  66 /* Initializes an uninitialized inode bitmap */
  67 static int ext4_init_inode_bitmap(struct super_block *sb,
  68                                        struct buffer_head *bh,
  69                                        ext4_group_t block_group,
  70                                        struct ext4_group_desc *gdp)
  71 {
  72         struct ext4_group_info *grp;
  73         struct ext4_sb_info *sbi = EXT4_SB(sb);
  74         J_ASSERT_BH(bh, buffer_locked(bh));
  75
  76         /* If checksum is bad mark all blocks and inodes use to prevent
  77          * allocation, essentially implementing a per-group read-only flag. */
  78         if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
  79                 ext4_error(sb, "Checksum bad for group %u", block_group);
  80                 grp = ext4_get_group_info(sb, block_group);
  81                 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
  82                         percpu_counter_sub(&sbi->s_freeclusters_counter,
  83                                            grp->bb_free);
  84                 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
  85                 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
  86                         int count;
  87                         count = ext4_free_inodes_count(sb, gdp);
  88                         percpu_counter_sub(&sbi->s_freeinodes_counter,
  89                                            count);
  90                 }
  91                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
  92                 return -EFSBADCRC;
  93         }
  94
  95         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
  96         ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
  97                         bh->b_data);
  98         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
  99                                    EXT4_INODES_PER_GROUP(sb) / 8);
 100         ext4_group_desc_csum_set(sb, block_group, gdp);
 101
 102         return 0;
 103 }
 104
 105 void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
 106 {
 107         if (uptodate) {
 108                 set_buffer_uptodate(bh);
 109                 set_bitmap_uptodate(bh);
 110         }
 111         unlock_buffer(bh);
 112         put_bh(bh);
 113 }
 114
 115 static int ext4_validate_inode_bitmap(struct super_block *sb,
 116                                       struct ext4_group_desc *desc,
 117                                       ext4_group_t block_group,
 118                                       struct buffer_head *bh)
 119 {
 120         ext4_fsblk_t    blk;
 121         struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
 122         struct ext4_sb_info *sbi = EXT4_SB(sb);
 123
 124         if (buffer_verified(bh))
 125                 return 0;
 126         if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
 127                 return -EFSCORRUPTED;
 128
 129         ext4_lock_group(sb, block_group);
 130         blk = ext4_inode_bitmap(sb, desc);
 131         if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
 132                                            EXT4_INODES_PER_GROUP(sb) / 8)) {
 133                 ext4_unlock_group(sb, block_group);
 134                 ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
 135                            "inode_bitmap = %llu", block_group, blk);
 136                 grp = ext4_get_group_info(sb, block_group);
 137                 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 138                         int count;
 139                         count = ext4_free_inodes_count(sb, desc);
 140                         percpu_counter_sub(&sbi->s_freeinodes_counter,
 141                                            count);
 142                 }
 143                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
 144                 return -EFSBADCRC;
 145         }
 146         set_buffer_verified(bh);
 147         ext4_unlock_group(sb, block_group);
 148         return 0;
 149 }
 150
 151 /*
 152  * Read the inode allocation bitmap for a given block_group, reading
 153  * into the specified slot in the superblock's bitmap cache.
 154  *
 155  * Return buffer_head of bitmap on success or NULL.
 156  */
 157 static struct buffer_head *
 158 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 159 {
 160         struct ext4_group_desc *desc;
 161         struct buffer_head *bh = NULL;
 162         ext4_fsblk_t bitmap_blk;
 163         int err;
 164
 165         desc = ext4_get_group_desc(sb, block_group, NULL);
 166         if (!desc)
 167                 return ERR_PTR(-EFSCORRUPTED);
 168
 169         bitmap_blk = ext4_inode_bitmap(sb, desc);
 170         bh = sb_getblk(sb, bitmap_blk);
 171         if (unlikely(!bh)) {
 172                 ext4_error(sb, "Cannot read inode bitmap - "
 173                             "block_group = %u, inode_bitmap = %llu",
 174                             block_group, bitmap_blk);
 175                 return ERR_PTR(-EIO);
 176         }
 177         if (bitmap_uptodate(bh))
 178                 goto verify;
 179
 180         lock_buffer(bh);
 181         if (bitmap_uptodate(bh)) {
 182                 unlock_buffer(bh);
 183                 goto verify;
 184         }
 185
 186         ext4_lock_group(sb, block_group);
 187         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 188                 err = ext4_init_inode_bitmap(sb, bh, block_group, desc);
 189                 set_bitmap_uptodate(bh);
 190                 set_buffer_uptodate(bh);
 191                 set_buffer_verified(bh);
 192                 ext4_unlock_group(sb, block_group);
 193                 unlock_buffer(bh);
 194                 if (err)
 195                         goto out;
 196                 return bh;
 197         }
 198         ext4_unlock_group(sb, block_group);
 199
 200         if (buffer_uptodate(bh)) {
 201                 /*
 202                  * if not uninit if bh is uptodate,
 203                  * bitmap is also uptodate
 204                  */
 205                 set_bitmap_uptodate(bh);
 206                 unlock_buffer(bh);
 207                 goto verify;
 208         }
 209         /*
 210          * submit the buffer_head for reading
 211          */
 212         trace_ext4_load_inode_bitmap(sb, block_group);
 213         bh->b_end_io = ext4_end_bitmap_read;
 214         get_bh(bh);
 215         submit_bh(READ | REQ_META | REQ_PRIO, bh);
 216         wait_on_buffer(bh);
 217         if (!buffer_uptodate(bh)) {
 218                 put_bh(bh);
 219                 ext4_error(sb, "Cannot read inode bitmap - "
 220                            "block_group = %u, inode_bitmap = %llu",
 221                            block_group, bitmap_blk);
 222                 return ERR_PTR(-EIO);
 223         }
 224
 225 verify:
 226         err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
 227         if (err)
 228                 goto out;
 229         return bh;
 230 out:
 231         put_bh(bh);
 232         return ERR_PTR(err);
 233 }
 234
 235 /*
 236  * NOTE! When we get the inode, we're the only people
 237  * that have access to it, and as such there are no
 238  * race conditions we have to worry about. The inode
 239  * is not on the hash-lists, and it cannot be reached
 240  * through the filesystem because the directory entry
 241  * has been deleted earlier.
 242  *
 243  * HOWEVER: we must make sure that we get no aliases,
 244  * which means that we have to call "clear_inode()"
 245  * _before_ we mark the inode not in use in the inode
 246  * bitmaps. Otherwise a newly created file might use
 247  * the same inode number (not actually the same pointer
 248  * though), and then we'd have two inodes sharing the
 249  * same inode number and space on the harddisk.
 250  */
 251 void ext4_free_inode(handle_t *handle, struct inode *inode)
 252 {
 253         struct super_block *sb = inode->i_sb;
 254         int is_directory;
 255         unsigned long ino;
 256         struct buffer_head *bitmap_bh = NULL;
 257         struct buffer_head *bh2;
 258         ext4_group_t block_group;
 259         unsigned long bit;
 260         struct ext4_group_desc *gdp;
 261         struct ext4_super_block *es;
 262         struct ext4_sb_info *sbi;
 263         int fatal = 0, err, count, cleared;
 264         struct ext4_group_info *grp;
 265
 266         if (!sb) {
 267                 printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
 268                        "nonexistent device\n", __func__, __LINE__);
 269                 return;
 270         }
 271         if (atomic_read(&inode->i_count) > 1) {
 272                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
 273                          __func__, __LINE__, inode->i_ino,
 274                          atomic_read(&inode->i_count));
 275                 return;
 276         }
 277         if (inode->i_nlink) {
 278                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
 279                          __func__, __LINE__, inode->i_ino, inode->i_nlink);
 280                 return;
 281         }
 282         sbi = EXT4_SB(sb);
 283
 284         ino = inode->i_ino;
 285         ext4_debug("freeing inode %lu\n", ino);
 286         trace_ext4_free_inode(inode);
 287
 288         /*
 289          * Note: we must free any quota before locking the superblock,
 290          * as writing the quota to disk may need the lock as well.
 291          */
 292         dquot_initialize(inode);
 293         ext4_xattr_delete_inode(handle, inode);
 294         dquot_free_inode(inode);
 295         dquot_drop(inode);
 296
 297         is_directory = S_ISDIR(inode->i_mode);
 298
 299         /* Do this BEFORE marking the inode not in use or returning an error */
 300         ext4_clear_inode(inode);
 301
 302         es = EXT4_SB(sb)->s_es;
 303         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 304                 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
 305                 goto error_return;
 306         }
 307         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 308         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 309         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 310         /* Don't bother if the inode bitmap is corrupt. */
 311         grp = ext4_get_group_info(sb, block_group);
 312         if (IS_ERR(bitmap_bh)) {
 313                 fatal = PTR_ERR(bitmap_bh);
 314                 bitmap_bh = NULL;
 315                 goto error_return;
 316         }
 317         if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
 318                 fatal = -EFSCORRUPTED;
 319                 goto error_return;
 320         }
 321
 322         BUFFER_TRACE(bitmap_bh, "get_write_access");
 323         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 324         if (fatal)
 325                 goto error_return;
 326
 327         fatal = -ESRCH;
 328         gdp = ext4_get_group_desc(sb, block_group, &bh2);
 329         if (gdp) {
 330                 BUFFER_TRACE(bh2, "get_write_access");
 331                 fatal = ext4_journal_get_write_access(handle, bh2);
 332         }
 333         ext4_lock_group(sb, block_group);
 334         cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
 335         if (fatal || !cleared) {
 336                 ext4_unlock_group(sb, block_group);
 337                 goto out;
 338         }
 339
 340         count = ext4_free_inodes_count(sb, gdp) + 1;
 341         ext4_free_inodes_set(sb, gdp, count);
 342         if (is_directory) {
 343                 count = ext4_used_dirs_count(sb, gdp) - 1;
 344                 ext4_used_dirs_set(sb, gdp, count);
 345                 percpu_counter_dec(&sbi->s_dirs_counter);
 346         }
 347         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
 348                                    EXT4_INODES_PER_GROUP(sb) / 8);
 349         ext4_group_desc_csum_set(sb, block_group, gdp);
 350         ext4_unlock_group(sb, block_group);
 351
 352         percpu_counter_inc(&sbi->s_freeinodes_counter);
 353         if (sbi->s_log_groups_per_flex) {
 354                 ext4_group_t f = ext4_flex_group(sbi, block_group);
 355
 356                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 357                 if (is_directory)
 358                         atomic_dec(&sbi->s_flex_groups[f].used_dirs);
 359         }
 360         BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 361         fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
 362 out:
 363         if (cleared) {
 364                 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 365                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 366                 if (!fatal)
 367                         fatal = err;
 368         } else {
 369                 ext4_error(sb, "bit already cleared for inode %lu", ino);
 370                 if (gdp && !EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 371                         int count;
 372                         count = ext4_free_inodes_count(sb, gdp);
 373                         percpu_counter_sub(&sbi->s_freeinodes_counter,
 374                                            count);
 375                 }
 376                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
 377         }
 378
 379 error_return:
 380         brelse(bitmap_bh);
 381         ext4_std_error(sb, fatal);
 382 }
 383
 384 struct orlov_stats {
 385         __u64 free_clusters;
 386         __u32 free_inodes;
 387         __u32 used_dirs;
 388 };
 389
 390 /*
 391  * Helper function for Orlov's allocator; returns critical information
 392  * for a particular block group or flex_bg.  If flex_size is 1, then g
 393  * is a block group number; otherwise it is flex_bg number.
 394  */
 395 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 396                             int flex_size, struct orlov_stats *stats)
 397 {
 398         struct ext4_group_desc *desc;
 399         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
 400
 401         if (flex_size > 1) {
 402                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
 403                 stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
 404                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
 405                 return;
 406         }
 407
 408         desc = ext4_get_group_desc(sb, g, NULL);
 409         if (desc) {
 410                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
 411                 stats->free_clusters = ext4_free_group_clusters(sb, desc);
 412                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
 413         } else {
 414                 stats->free_inodes = 0;
 415                 stats->free_clusters = 0;
 416                 stats->used_dirs = 0;
 417         }
 418 }
 419
 420 /*
 421  * Orlov's allocator for directories.
 422  *
 423  * We always try to spread first-level directories.
 424  *
 425  * If there are blockgroups with both free inodes and free blocks counts
 426  * not worse than average we return one with smallest directory count.
 427  * Otherwise we simply return a random group.
 428  *
 429  * For the rest rules look so:
 430  *
 431  * It's OK to put directory into a group unless
 432  * it has too many directories already (max_dirs) or
 433  * it has too few free inodes left (min_inodes) or
 434  * it has too few free blocks left (min_blocks) or
 435  * Parent's group is preferred, if it doesn't satisfy these
 436  * conditions we search cyclically through the rest. If none
 437  * of the groups look good we just look for a group with more
 438  * free inodes than average (starting at parent's group).
 439  */
 440
 441 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 442                             ext4_group_t *group, umode_t mode,
 443                             const struct qstr *qstr)
 444 {
 445         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 446         struct ext4_sb_info *sbi = EXT4_SB(sb);
 447         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 448         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 449         unsigned int freei, avefreei, grp_free;
 450         ext4_fsblk_t freeb, avefreec;
 451         unsigned int ndirs;
 452         int max_dirs, min_inodes;
 453         ext4_grpblk_t min_clusters;
 454         ext4_group_t i, grp, g, ngroups;
 455         struct ext4_group_desc *desc;
 456         struct orlov_stats stats;
 457         int flex_size = ext4_flex_bg_size(sbi);
 458         struct dx_hash_info hinfo;
 459
 460         ngroups = real_ngroups;
 461         if (flex_size > 1) {
 462                 ngroups = (real_ngroups + flex_size - 1) >>
 463                         sbi->s_log_groups_per_flex;
 464                 parent_group >>= sbi->s_log_groups_per_flex;
 465         }
 466
 467         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 468         avefreei = freei / ngroups;
 469         freeb = EXT4_C2B(sbi,
 470                 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
 471         avefreec = freeb;
 472         do_div(avefreec, ngroups);
 473         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 474
 475         if (S_ISDIR(mode) &&
 476             ((parent == d_inode(sb->s_root)) ||
 477              (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
 478                 int best_ndir = inodes_per_group;
 479                 int ret = -1;
 480
 481                 if (qstr) {
 482                         hinfo.hash_version = DX_HASH_HALF_MD4;
 483                         hinfo.seed = sbi->s_hash_seed;
 484                         ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
 485                         grp = hinfo.hash;
 486                 } else
 487                         grp = prandom_u32();
 488                 parent_group = (unsigned)grp % ngroups;
 489                 for (i = 0; i < ngroups; i++) {
 490                         g = (parent_group + i) % ngroups;
 491                         get_orlov_stats(sb, g, flex_size, &stats);
 492                         if (!stats.free_inodes)
 493                                 continue;
 494                         if (stats.used_dirs >= best_ndir)
 495                                 continue;
 496                         if (stats.free_inodes < avefreei)
 497                                 continue;
 498                         if (stats.free_clusters < avefreec)
 499                                 continue;
 500                         grp = g;
 501                         ret = 0;
 502                         best_ndir = stats.used_dirs;
 503                 }
 504                 if (ret)
 505                         goto fallback;
 506         found_flex_bg:
 507                 if (flex_size == 1) {
 508                         *group = grp;
 509                         return 0;
 510                 }
 511
 512                 /*
 513                  * We pack inodes at the beginning of the flexgroup's
 514                  * inode tables.  Block allocation decisions will do
 515                  * something similar, although regular files will
 516                  * start at 2nd block group of the flexgroup.  See
 517                  * ext4_ext_find_goal() and ext4_find_near().
 518                  */
 519                 grp *= flex_size;
 520                 for (i = 0; i < flex_size; i++) {
 521                         if (grp+i >= real_ngroups)
 522                                 break;
 523                         desc = ext4_get_group_desc(sb, grp+i, NULL);
 524                         if (desc && ext4_free_inodes_count(sb, desc)) {
 525                                 *group = grp+i;
 526                                 return 0;
 527                         }
 528                 }
 529                 goto fallback;
 530         }
 531
 532         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 533         min_inodes = avefreei - inodes_per_group*flex_size / 4;
 534         if (min_inodes < 1)
 535                 min_inodes = 1;
 536         min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
 537
 538         /*
 539          * Start looking in the flex group where we last allocated an
 540          * inode for this parent directory
 541          */
 542         if (EXT4_I(parent)->i_last_alloc_group != ~0) {
 543                 parent_group = EXT4_I(parent)->i_last_alloc_group;
 544                 if (flex_size > 1)
 545                         parent_group >>= sbi->s_log_groups_per_flex;
 546         }
 547
 548         for (i = 0; i < ngroups; i++) {
 549                 grp = (parent_group + i) % ngroups;
 550                 get_orlov_stats(sb, grp, flex_size, &stats);
 551                 if (stats.used_dirs >= max_dirs)
 552                         continue;
 553                 if (stats.free_inodes < min_inodes)
 554                         continue;
 555                 if (stats.free_clusters < min_clusters)
 556                         continue;
 557                 goto found_flex_bg;
 558         }
 559
 560 fallback:
 561         ngroups = real_ngroups;
 562         avefreei = freei / ngroups;
 563 fallback_retry:
 564         parent_group = EXT4_I(parent)->i_block_group;
 565         for (i = 0; i < ngroups; i++) {
 566                 grp = (parent_group + i) % ngroups;
 567                 desc = ext4_get_group_desc(sb, grp, NULL);
 568                 if (desc) {
 569                         grp_free = ext4_free_inodes_count(sb, desc);
 570                         if (grp_free && grp_free >= avefreei) {
 571                                 *group = grp;
 572                                 return 0;
 573                         }
 574                 }
 575         }
 576
 577         if (avefreei) {
 578                 /*
 579                  * The free-inodes counter is approximate, and for really small
 580                  * filesystems the above test can fail to find any blockgroups
 581                  */
 582                 avefreei = 0;
 583                 goto fallback_retry;
 584         }
 585
 586         return -1;
 587 }
 588
 589 static int find_group_other(struct super_block *sb, struct inode *parent,
 590                             ext4_group_t *group, umode_t mode)
 591 {
 592         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 593         ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
 594         struct ext4_group_desc *desc;
 595         int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
 596
 597         /*
 598          * Try to place the inode is the same flex group as its
 599          * parent.  If we can't find space, use the Orlov algorithm to
 600          * find another flex group, and store that information in the
 601          * parent directory's inode information so that use that flex
 602          * group for future allocations.
 603          */
 604         if (flex_size > 1) {
 605                 int retry = 0;
 606
 607         try_again:
 608                 parent_group &= ~(flex_size-1);
 609                 last = parent_group + flex_size;
 610                 if (last > ngroups)
 611                         last = ngroups;
 612                 for  (i = parent_group; i < last; i++) {
 613                         desc = ext4_get_group_desc(sb, i, NULL);
 614                         if (desc && ext4_free_inodes_count(sb, desc)) {
 615                                 *group = i;
 616                                 return 0;
 617                         }
 618                 }
 619                 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
 620                         retry = 1;
 621                         parent_group = EXT4_I(parent)->i_last_alloc_group;
 622                         goto try_again;
 623                 }
 624                 /*
 625                  * If this didn't work, use the Orlov search algorithm
 626                  * to find a new flex group; we pass in the mode to
 627                  * avoid the topdir algorithms.
 628                  */
 629                 *group = parent_group + flex_size;
 630                 if (*group > ngroups)
 631                         *group = 0;
 632                 return find_group_orlov(sb, parent, group, mode, NULL);
 633         }
 634
 635         /*
 636          * Try to place the inode in its parent directory
 637          */
 638         *group = parent_group;
 639         desc = ext4_get_group_desc(sb, *group, NULL);
 640         if (desc && ext4_free_inodes_count(sb, desc) &&
 641             ext4_free_group_clusters(sb, desc))
 642                 return 0;
 643
 644         /*
 645          * We're going to place this inode in a different blockgroup from its
 646          * parent.  We want to cause files in a common directory to all land in
 647          * the same blockgroup.  But we want files which are in a different
 648          * directory which shares a blockgroup with our parent to land in a
 649          * different blockgroup.
 650          *
 651          * So add our directory's i_ino into the starting point for the hash.
 652          */
 653         *group = (*group + parent->i_ino) % ngroups;
 654
 655         /*
 656          * Use a quadratic hash to find a group with a free inode and some free
 657          * blocks.
 658          */
 659         for (i = 1; i < ngroups; i <<= 1) {
 660                 *group += i;
 661                 if (*group >= ngroups)
 662                         *group -= ngroups;
 663                 desc = ext4_get_group_desc(sb, *group, NULL);
 664                 if (desc && ext4_free_inodes_count(sb, desc) &&
 665                     ext4_free_group_clusters(sb, desc))
 666                         return 0;
 667         }
 668
 669         /*
 670          * That failed: try linear search for a free inode, even if that group
 671          * has no free blocks.
 672          */
 673         *group = parent_group;
 674         for (i = 0; i < ngroups; i++) {
 675                 if (++*group >= ngroups)
 676                         *group = 0;
 677                 desc = ext4_get_group_desc(sb, *group, NULL);
 678                 if (desc && ext4_free_inodes_count(sb, desc))
 679                         return 0;
 680         }
 681
 682         return -1;
 683 }
 684
 685 /*
 686  * In no journal mode, if an inode has recently been deleted, we want
 687  * to avoid reusing it until we're reasonably sure the inode table
 688  * block has been written back to disk.  (Yes, these values are
 689  * somewhat arbitrary...)
 690  */
 691 #define RECENTCY_MIN    5
 692 #define RECENTCY_DIRTY  30
 693
 694 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
 695 {
 696         struct ext4_group_desc  *gdp;
 697         struct ext4_inode       *raw_inode;
 698         struct buffer_head      *bh;
 699         unsigned long           dtime, now;
 700         int     inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
 701         int     offset, ret = 0, recentcy = RECENTCY_MIN;
 702
 703         gdp = ext4_get_group_desc(sb, group, NULL);
 704         if (unlikely(!gdp))
 705                 return 0;
 706
 707         bh = sb_getblk(sb, ext4_inode_table(sb, gdp) +
 708                        (ino / inodes_per_block));
 709         if (unlikely(!bh) || !buffer_uptodate(bh))
 710                 /*
 711                  * If the block is not in the buffer cache, then it
 712                  * must have been written out.
 713                  */
 714                 goto out;
 715
 716         offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
 717         raw_inode = (struct ext4_inode *) (bh->b_data + offset);
 718         dtime = le32_to_cpu(raw_inode->i_dtime);
 719         now = get_seconds();
 720         if (buffer_dirty(bh))
 721                 recentcy += RECENTCY_DIRTY;
 722
 723         if (dtime && (dtime < now) && (now < dtime + recentcy))
 724                 ret = 1;
 725 out:
 726         brelse(bh);
 727         return ret;
 728 }
 729
 730 /*
 731  * There are two policies for allocating an inode.  If the new inode is
 732  * a directory, then a forward search is made for a block group with both
 733  * free space and a low directory-to-inode ratio; if that fails, then of
 734  * the groups with above-average free space, that group with the fewest
 735  * directories already is chosen.
 736  *
 737  * For other inodes, search forward from the parent directory's block
 738  * group to find a free inode.
 739  */
 740 struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 741                                umode_t mode, const struct qstr *qstr,
 742                                __u32 goal, uid_t *owner, int handle_type,
 743                                unsigned int line_no, int nblocks)
 744 {
 745         struct super_block *sb;
 746         struct buffer_head *inode_bitmap_bh = NULL;
 747         struct buffer_head *group_desc_bh;
 748         ext4_group_t ngroups, group = 0;
 749         unsigned long ino = 0;
 750         struct inode *inode;
 751         struct ext4_group_desc *gdp = NULL;
 752         struct ext4_inode_info *ei;
 753         struct ext4_sb_info *sbi;
 754         int ret2, err;
 755         struct inode *ret;
 756         ext4_group_t i;
 757         ext4_group_t flex_group;
 758         struct ext4_group_info *grp;
 759         int encrypt = 0;
 760
 761         /* Cannot create files in a deleted directory */
 762         if (!dir || !dir->i_nlink)
 763                 return ERR_PTR(-EPERM);
 764
 765         if ((ext4_encrypted_inode(dir) ||
 766              DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb))) &&
 767             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
 768                 err = ext4_get_encryption_info(dir);
 769                 if (err)
 770                         return ERR_PTR(err);
 771                 if (ext4_encryption_info(dir) == NULL)
 772                         return ERR_PTR(-EPERM);
 773                 if (!handle)
 774                         nblocks += EXT4_DATA_TRANS_BLOCKS(dir->i_sb);
 775                 encrypt = 1;
 776         }
 777
 778         sb = dir->i_sb;
 779         ngroups = ext4_get_groups_count(sb);
 780         trace_ext4_request_inode(dir, mode);
 781         inode = new_inode(sb);
 782         if (!inode)
 783                 return ERR_PTR(-ENOMEM);
 784         ei = EXT4_I(inode);
 785         sbi = EXT4_SB(sb);
 786
 787         /*
 788          * Initalize owners and quota early so that we don't have to account
 789          * for quota initialization worst case in standard inode creating
 790          * transaction
 791          */
 792         if (owner) {
 793                 inode->i_mode = mode;
 794                 i_uid_write(inode, owner[0]);
 795                 i_gid_write(inode, owner[1]);
 796         } else if (test_opt(sb, GRPID)) {
 797                 inode->i_mode = mode;
 798                 inode->i_uid = current_fsuid();
 799                 inode->i_gid = dir->i_gid;
 800         } else
 801                 inode_init_owner(inode, dir, mode);
 802         err = dquot_initialize(inode);
 803         if (err)
 804                 goto out;
 805
 806         if (!goal)
 807                 goal = sbi->s_inode_goal;
 808
 809         if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
 810                 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
 811                 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
 812                 ret2 = 0;
 813                 goto got_group;
 814         }
 815
 816         if (S_ISDIR(mode))
 817                 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
 818         else
 819                 ret2 = find_group_other(sb, dir, &group, mode);
 820
 821 got_group:
 822         EXT4_I(dir)->i_last_alloc_group = group;
 823         err = -ENOSPC;
 824         if (ret2 == -1)
 825                 goto out;
 826
 827         /*
 828          * Normally we will only go through one pass of this loop,
 829          * unless we get unlucky and it turns out the group we selected
 830          * had its last inode grabbed by someone else.
 831          */
 832         for (i = 0; i < ngroups; i++, ino = 0) {
 833                 err = -EIO;
 834
 835                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 836                 if (!gdp)
 837                         goto out;
 838
 839                 /*
 840                  * Check free inodes count before loading bitmap.
 841                  */
 842                 if (ext4_free_inodes_count(sb, gdp) == 0) {
 843                         if (++group == ngroups)
 844                                 group = 0;
 845                         continue;
 846                 }
 847
 848                 grp = ext4_get_group_info(sb, group);
 849                 /* Skip groups with already-known suspicious inode tables */
 850                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 851                         if (++group == ngroups)
 852                                 group = 0;
 853                         continue;
 854                 }
 855
 856                 brelse(inode_bitmap_bh);
 857                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 858                 /* Skip groups with suspicious inode tables */
 859                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
 860                     IS_ERR(inode_bitmap_bh)) {
 861                         inode_bitmap_bh = NULL;
 862                         if (++group == ngroups)
 863                                 group = 0;
 864                         continue;
 865                 }
 866
 867 repeat_in_this_group:
 868                 ino = ext4_find_next_zero_bit((unsigned long *)
 869                                               inode_bitmap_bh->b_data,
 870                                               EXT4_INODES_PER_GROUP(sb), ino);
 871                 if (ino >= EXT4_INODES_PER_GROUP(sb))
 872                         goto next_group;
 873                 if (group == 0 && (ino+1) < EXT4_FIRST_INO(sb)) {
 874                         ext4_error(sb, "reserved inode found cleared - "
 875                                    "inode=%lu", ino + 1);
 876                         continue;
 877                 }
 878                 if ((EXT4_SB(sb)->s_journal == NULL) &&
 879                     recently_deleted(sb, group, ino)) {
 880                         ino++;
 881                         goto next_inode;
 882                 }
 883                 if (!handle) {
 884                         BUG_ON(nblocks <= 0);
 885                         handle = __ext4_journal_start_sb(dir->i_sb, line_no,
 886                                                          handle_type, nblocks,
 887                                                          0);
 888                         if (IS_ERR(handle)) {
 889                                 err = PTR_ERR(handle);
 890                                 ext4_std_error(sb, err);
 891                                 goto out;
 892                         }
 893                 }
 894                 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 895                 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
 896                 if (err) {
 897                         ext4_std_error(sb, err);
 898                         goto out;
 899                 }
 900                 ext4_lock_group(sb, group);
 901                 ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
 902                 ext4_unlock_group(sb, group);
 903                 ino++;          /* the inode bitmap is zero-based */
 904                 if (!ret2)
 905                         goto got; /* we grabbed the inode! */
 906 next_inode:
 907                 if (ino < EXT4_INODES_PER_GROUP(sb))
 908                         goto repeat_in_this_group;
 909 next_group:
 910                 if (++group == ngroups)
 911                         group = 0;
 912         }
 913         err = -ENOSPC;
 914         goto out;
 915
 916 got:
 917         BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
 918         err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
 919         if (err) {
 920                 ext4_std_error(sb, err);
 921                 goto out;
 922         }
 923
 924         BUFFER_TRACE(group_desc_bh, "get_write_access");
 925         err = ext4_journal_get_write_access(handle, group_desc_bh);
 926         if (err) {
 927                 ext4_std_error(sb, err);
 928                 goto out;
 929         }
 930
 931         /* We may have to initialize the block bitmap if it isn't already */
 932         if (ext4_has_group_desc_csum(sb) &&
 933             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 934                 struct buffer_head *block_bitmap_bh;
 935
 936                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 937                 if (IS_ERR(block_bitmap_bh)) {
 938                         err = PTR_ERR(block_bitmap_bh);
 939                         goto out;
 940                 }
 941                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 942                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 943                 if (err) {
 944                         brelse(block_bitmap_bh);
 945                         ext4_std_error(sb, err);
 946                         goto out;
 947                 }
 948
 949                 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
 950                 err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
 951
 952                 /* recheck and clear flag under lock if we still need to */
 953                 ext4_lock_group(sb, group);
 954                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 955                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 956                         ext4_free_group_clusters_set(sb, gdp,
 957                                 ext4_free_clusters_after_init(sb, group, gdp));
 958                         ext4_block_bitmap_csum_set(sb, group, gdp,
 959                                                    block_bitmap_bh);
 960                         ext4_group_desc_csum_set(sb, group, gdp);
 961                 }
 962                 ext4_unlock_group(sb, group);
 963                 brelse(block_bitmap_bh);
 964
 965                 if (err) {
 966                         ext4_std_error(sb, err);
 967                         goto out;
 968                 }
 969         }
 970
 971         /* Update the relevant bg descriptor fields */
 972         if (ext4_has_group_desc_csum(sb)) {
 973                 int free;
 974                 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
 975
 976                 down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
 977                 ext4_lock_group(sb, group); /* while we modify the bg desc */
 978                 free = EXT4_INODES_PER_GROUP(sb) -
 979                         ext4_itable_unused_count(sb, gdp);
 980                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 981                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 982                         free = 0;
 983                 }
 984                 /*
 985                  * Check the relative inode number against the last used
 986                  * relative inode number in this group. if it is greater
 987                  * we need to update the bg_itable_unused count
 988                  */
 989                 if (ino > free)
 990                         ext4_itable_unused_set(sb, gdp,
 991                                         (EXT4_INODES_PER_GROUP(sb) - ino));
 992                 up_read(&grp->alloc_sem);
 993         } else {
 994                 ext4_lock_group(sb, group);
 995         }
 996
 997         ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
 998         if (S_ISDIR(mode)) {
 999                 ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1000                 if (sbi->s_log_groups_per_flex) {
1001                         ext4_group_t f = ext4_flex_group(sbi, group);
1002
1003                         atomic_inc(&sbi->s_flex_groups[f].used_dirs);
1004                 }
1005         }
1006         if (ext4_has_group_desc_csum(sb)) {
1007                 ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1008                                            EXT4_INODES_PER_GROUP(sb) / 8);
1009                 ext4_group_desc_csum_set(sb, group, gdp);
1010         }
1011         ext4_unlock_group(sb, group);
1012
1013         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1014         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1015         if (err) {
1016                 ext4_std_error(sb, err);
1017                 goto out;
1018         }
1019
1020         percpu_counter_dec(&sbi->s_freeinodes_counter);
1021         if (S_ISDIR(mode))
1022                 percpu_counter_inc(&sbi->s_dirs_counter);
1023
1024         if (sbi->s_log_groups_per_flex) {
1025                 flex_group = ext4_flex_group(sbi, group);
1026                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
1027         }
1028
1029         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1030         /* This is the optimal IO size (for stat), not the fs block size */
1031         inode->i_blocks = 0;
1032         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
1033                                                        ext4_current_time(inode);
1034
1035         memset(ei->i_data, 0, sizeof(ei->i_data));
1036         ei->i_dir_start_lookup = 0;
1037         ei->i_disksize = 0;
1038
1039         /* Don't inherit extent flag from directory, amongst others. */
1040         ei->i_flags =
1041                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1042         ei->i_file_acl = 0;
1043         ei->i_dtime = 0;
1044         ei->i_block_group = group;
1045         ei->i_last_alloc_group = ~0;
1046
1047         ext4_set_inode_flags(inode);
1048         if (IS_DIRSYNC(inode))
1049                 ext4_handle_sync(handle);
1050         if (insert_inode_locked(inode) < 0) {
1051                 /*
1052                  * Likely a bitmap corruption causing inode to be allocated
1053                  * twice.
1054                  */
1055                 err = -EIO;
1056                 ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1057                            inode->i_ino);
1058                 goto out;
1059         }
1060         spin_lock(&sbi->s_next_gen_lock);
1061         inode->i_generation = sbi->s_next_generation++;
1062         spin_unlock(&sbi->s_next_gen_lock);
1063
1064         /* Precompute checksum seed for inode metadata */
1065         if (ext4_has_metadata_csum(sb)) {
1066                 __u32 csum;
1067                 __le32 inum = cpu_to_le32(inode->i_ino);
1068                 __le32 gen = cpu_to_le32(inode->i_generation);
1069                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1070                                    sizeof(inum));
1071                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1072                                               sizeof(gen));
1073         }
1074
1075         ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1076         ext4_set_inode_state(inode, EXT4_STATE_NEW);
1077
1078         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
1079         ei->i_inline_off = 0;
1080         if (ext4_has_feature_inline_data(sb))
1081                 ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1082         ret = inode;
1083         err = dquot_alloc_inode(inode);
1084         if (err)
1085                 goto fail_drop;
1086
1087         err = ext4_init_acl(handle, inode, dir);
1088         if (err)
1089                 goto fail_free_drop;
1090
1091         err = ext4_init_security(handle, inode, dir, qstr);
1092         if (err)
1093                 goto fail_free_drop;
1094
1095         if (ext4_has_feature_extents(sb)) {
1096                 /* set extent flag only for directory, file and normal symlink*/
1097                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1098                         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1099                         ext4_ext_tree_init(handle, inode);
1100                 }
1101         }
1102
1103         if (ext4_handle_valid(handle)) {
1104                 ei->i_sync_tid = handle->h_transaction->t_tid;
1105                 ei->i_datasync_tid = handle->h_transaction->t_tid;
1106         }
1107
1108         if (encrypt) {
1109                 err = ext4_inherit_context(dir, inode);
1110                 if (err)
1111                         goto fail_free_drop;
1112         }
1113
1114         err = ext4_mark_inode_dirty(handle, inode);
1115         if (err) {
1116                 ext4_std_error(sb, err);
1117                 goto fail_free_drop;
1118         }
1119
1120         ext4_debug("allocating inode %lu\n", inode->i_ino);
1121         trace_ext4_allocate_inode(inode, dir, mode);
1122         brelse(inode_bitmap_bh);
1123         return ret;
1124
1125 fail_free_drop:
1126         dquot_free_inode(inode);
1127 fail_drop:
1128         clear_nlink(inode);
1129         unlock_new_inode(inode);
1130 out:
1131         dquot_drop(inode);
1132         inode->i_flags |= S_NOQUOTA;
1133         iput(inode);
1134         brelse(inode_bitmap_bh);
1135         return ERR_PTR(err);
1136 }
1137
1138 /* Verify that we are loading a valid orphan from disk */
1139 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1140 {
1141         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1142         ext4_group_t block_group;
1143         int bit;
1144         struct buffer_head *bitmap_bh;
1145         struct inode *inode = NULL;
1146         long err = -EIO;
1147
1148         /* Error cases - e2fsck has already cleaned up for us */
1149         if (ino > max_ino) {
1150                 ext4_warning(sb, "bad orphan ino %lu!  e2fsck was run?", ino);
1151                 err = -EFSCORRUPTED;
1152                 goto error;
1153         }
1154
1155         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1156         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1157         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1158         if (IS_ERR(bitmap_bh)) {
1159                 err = PTR_ERR(bitmap_bh);
1160                 ext4_warning(sb, "inode bitmap error %ld for orphan %lu",
1161                              ino, err);
1162                 goto error;
1163         }
1164
1165         /* Having the inode bit set should be a 100% indicator that this
1166          * is a valid orphan (no e2fsck run on fs).  Orphans also include
1167          * inodes that were being truncated, so we can't check i_nlink==0.
1168          */
1169         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1170                 goto bad_orphan;
1171
1172         inode = ext4_iget(sb, ino);
1173         if (IS_ERR(inode))
1174                 goto iget_failed;
1175
1176         /*
1177          * If the orphans has i_nlinks > 0 then it should be able to be
1178          * truncated, otherwise it won't be removed from the orphan list
1179          * during processing and an infinite loop will result.
1180          */
1181         if (inode->i_nlink && !ext4_can_truncate(inode))
1182                 goto bad_orphan;
1183
1184         if (NEXT_ORPHAN(inode) > max_ino)
1185                 goto bad_orphan;
1186         brelse(bitmap_bh);
1187         return inode;
1188
1189 iget_failed:
1190         err = PTR_ERR(inode);
1191         inode = NULL;
1192 bad_orphan:
1193         ext4_warning(sb, "bad orphan inode %lu!  e2fsck was run?", ino);
1194         printk(KERN_WARNING "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1195                bit, (unsigned long long)bitmap_bh->b_blocknr,
1196                ext4_test_bit(bit, bitmap_bh->b_data));
1197         printk(KERN_WARNING "inode=%p\n", inode);
1198         if (inode) {
1199                 printk(KERN_WARNING "is_bad_inode(inode)=%d\n",
1200                        is_bad_inode(inode));
1201                 printk(KERN_WARNING "NEXT_ORPHAN(inode)=%u\n",
1202                        NEXT_ORPHAN(inode));
1203                 printk(KERN_WARNING "max_ino=%lu\n", max_ino);
1204                 printk(KERN_WARNING "i_nlink=%u\n", inode->i_nlink);
1205                 /* Avoid freeing blocks if we got a bad deleted inode */
1206                 if (inode->i_nlink == 0)
1207                         inode->i_blocks = 0;
1208                 iput(inode);
1209         }
1210         brelse(bitmap_bh);
1211 error:
1212         return ERR_PTR(err);
1213 }
1214
1215 unsigned long ext4_count_free_inodes(struct super_block *sb)
1216 {
1217         unsigned long desc_count;
1218         struct ext4_group_desc *gdp;
1219         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1220 #ifdef EXT4FS_DEBUG
1221         struct ext4_super_block *es;
1222         unsigned long bitmap_count, x;
1223         struct buffer_head *bitmap_bh = NULL;
1224
1225         es = EXT4_SB(sb)->s_es;
1226         desc_count = 0;
1227         bitmap_count = 0;
1228         gdp = NULL;
1229         for (i = 0; i < ngroups; i++) {
1230                 gdp = ext4_get_group_desc(sb, i, NULL);
1231                 if (!gdp)
1232                         continue;
1233                 desc_count += ext4_free_inodes_count(sb, gdp);
1234                 brelse(bitmap_bh);
1235                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1236                 if (IS_ERR(bitmap_bh)) {
1237                         bitmap_bh = NULL;
1238                         continue;
1239                 }
1240
1241                 x = ext4_count_free(bitmap_bh->b_data,
1242                                     EXT4_INODES_PER_GROUP(sb) / 8);
1243                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1244                         (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1245                 bitmap_count += x;
1246         }
1247         brelse(bitmap_bh);
1248         printk(KERN_DEBUG "ext4_count_free_inodes: "
1249                "stored = %u, computed = %lu, %lu\n",
1250                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1251         return desc_count;
1252 #else
1253         desc_count = 0;
1254         for (i = 0; i < ngroups; i++) {
1255                 gdp = ext4_get_group_desc(sb, i, NULL);
1256                 if (!gdp)
1257                         continue;
1258                 desc_count += ext4_free_inodes_count(sb, gdp);
1259                 cond_resched();
1260         }
1261         return desc_count;
1262 #endif
1263 }
1264
1265 /* Called at mount-time, super-block is locked */
1266 unsigned long ext4_count_dirs(struct super_block * sb)
1267 {
1268         unsigned long count = 0;
1269         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1270
1271         for (i = 0; i < ngroups; i++) {
1272                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1273                 if (!gdp)
1274                         continue;
1275                 count += ext4_used_dirs_count(sb, gdp);
1276         }
1277         return count;
1278 }
1279
1280 /*
1281  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1282  * inode table. Must be called without any spinlock held. The only place
1283  * where it is called from on active part of filesystem is ext4lazyinit
1284  * thread, so we do not need any special locks, however we have to prevent
1285  * inode allocation from the current group, so we take alloc_sem lock, to
1286  * block ext4_new_inode() until we are finished.
1287  */
1288 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1289                                  int barrier)
1290 {
1291         struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1292         struct ext4_sb_info *sbi = EXT4_SB(sb);
1293         struct ext4_group_desc *gdp = NULL;
1294         struct buffer_head *group_desc_bh;
1295         handle_t *handle;
1296         ext4_fsblk_t blk;
1297         int num, ret = 0, used_blks = 0;
1298
1299         /* This should not happen, but just to be sure check this */
1300         if (sb->s_flags & MS_RDONLY) {
1301                 ret = 1;
1302                 goto out;
1303         }
1304
1305         gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1306         if (!gdp)
1307                 goto out;
1308
1309         /*
1310          * We do not need to lock this, because we are the only one
1311          * handling this flag.
1312          */
1313         if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1314                 goto out;
1315
1316         handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1317         if (IS_ERR(handle)) {
1318                 ret = PTR_ERR(handle);
1319                 goto out;
1320         }
1321
1322         down_write(&grp->alloc_sem);
1323         /*
1324          * If inode bitmap was already initialized there may be some
1325          * used inodes so we need to skip blocks with used inodes in
1326          * inode table.
1327          */
1328         if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1329                 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1330                             ext4_itable_unused_count(sb, gdp)),
1331                             sbi->s_inodes_per_block);
1332
1333         if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1334                 ext4_error(sb, "Something is wrong with group %u: "
1335                            "used itable blocks: %d; "
1336                            "itable unused count: %u",
1337                            group, used_blks,
1338                            ext4_itable_unused_count(sb, gdp));
1339                 ret = 1;
1340                 goto err_out;
1341         }
1342
1343         blk = ext4_inode_table(sb, gdp) + used_blks;
1344         num = sbi->s_itb_per_group - used_blks;
1345
1346         BUFFER_TRACE(group_desc_bh, "get_write_access");
1347         ret = ext4_journal_get_write_access(handle,
1348                                             group_desc_bh);
1349         if (ret)
1350                 goto err_out;
1351
1352         /*
1353          * Skip zeroout if the inode table is full. But we set the ZEROED
1354          * flag anyway, because obviously, when it is full it does not need
1355          * further zeroing.
1356          */
1357         if (unlikely(num == 0))
1358                 goto skip_zeroout;
1359
1360         ext4_debug("going to zero out inode table in group %d\n",
1361                    group);
1362         ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1363         if (ret < 0)
1364                 goto err_out;
1365         if (barrier)
1366                 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1367
1368 skip_zeroout:
1369         ext4_lock_group(sb, group);
1370         gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1371         ext4_group_desc_csum_set(sb, group, gdp);
1372         ext4_unlock_group(sb, group);
1373
1374         BUFFER_TRACE(group_desc_bh,
1375                      "call ext4_handle_dirty_metadata");
1376         ret = ext4_handle_dirty_metadata(handle, NULL,
1377                                          group_desc_bh);
1378
1379 err_out:
1380         up_write(&grp->alloc_sem);
1381         ext4_journal_stop(handle);
1382 out:
1383         return ret;
1384 }