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 <linux/cred.h>
  25
  26 #include <asm/byteorder.h>
  27
  28 #include "ext4.h"
  29 #include "ext4_jbd2.h"
  30 #include "xattr.h"
  31 #include "acl.h"
  32
  33 #include <trace/events/ext4.h>
  34
  35 /*
  36  * ialloc.c contains the inodes allocation and deallocation routines
  37  */
  38
  39 /*
  40  * The free inodes are managed by bitmaps.  A file system contains several
  41  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  42  * block for inodes, N blocks for the inode table and data blocks.
  43  *
  44  * The file system contains group descriptors which are located after the
  45  * super block.  Each descriptor contains the number of the bitmap block and
  46  * the free blocks count in the block.
  47  */
  48
  49 /*
  50  * To avoid calling the atomic setbit hundreds or thousands of times, we only
  51  * need to use it within a single byte (to ensure we get endianness right).
  52  * We can use memset for the rest of the bitmap as there are no other users.
  53  */
  54 void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
  55 {
  56         int i;
  57
  58         if (start_bit >= end_bit)
  59                 return;
  60
  61         ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
  62         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
  63                 ext4_set_bit(i, bitmap);
  64         if (i < end_bit)
  65                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
  66 }
  67
  68 /* Initializes an uninitialized inode bitmap */
  69 static int ext4_init_inode_bitmap(struct super_block *sb,
  70                                        struct buffer_head *bh,
  71                                        ext4_group_t block_group,
  72                                        struct ext4_group_desc *gdp)
  73 {
  74         struct ext4_group_info *grp;
  75         struct ext4_sb_info *sbi = EXT4_SB(sb);
  76         J_ASSERT_BH(bh, buffer_locked(bh));
  77
  78         /* If checksum is bad mark all blocks and inodes use to prevent
  79          * allocation, essentially implementing a per-group read-only flag. */
  80         if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
  81                 grp = ext4_get_group_info(sb, block_group);
  82                 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
  83                         percpu_counter_sub(&sbi->s_freeclusters_counter,
  84                                            grp->bb_free);
  85                 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
  86                 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
  87                         int count;
  88                         count = ext4_free_inodes_count(sb, gdp);
  89                         percpu_counter_sub(&sbi->s_freeinodes_counter,
  90                                            count);
  91                 }
  92                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
  93                 return -EFSBADCRC;
  94         }
  95
  96         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
  97         ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
  98                         bh->b_data);
  99         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
 100                                    EXT4_INODES_PER_GROUP(sb) / 8);
 101         ext4_group_desc_csum_set(sb, block_group, gdp);
 102
 103         return 0;
 104 }
 105
 106 void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
 107 {
 108         if (uptodate) {
 109                 set_buffer_uptodate(bh);
 110                 set_bitmap_uptodate(bh);
 111         }
 112         unlock_buffer(bh);
 113         put_bh(bh);
 114 }
 115
 116 static int ext4_validate_inode_bitmap(struct super_block *sb,
 117                                       struct ext4_group_desc *desc,
 118                                       ext4_group_t block_group,
 119                                       struct buffer_head *bh)
 120 {
 121         ext4_fsblk_t    blk;
 122         struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
 123         struct ext4_sb_info *sbi = EXT4_SB(sb);
 124
 125         if (buffer_verified(bh))
 126                 return 0;
 127         if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
 128                 return -EFSCORRUPTED;
 129
 130         ext4_lock_group(sb, block_group);
 131         blk = ext4_inode_bitmap(sb, desc);
 132         if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
 133                                            EXT4_INODES_PER_GROUP(sb) / 8)) {
 134                 ext4_unlock_group(sb, block_group);
 135                 ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
 136                            "inode_bitmap = %llu", block_group, blk);
 137                 grp = ext4_get_group_info(sb, block_group);
 138                 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 139                         int count;
 140                         count = ext4_free_inodes_count(sb, desc);
 141                         percpu_counter_sub(&sbi->s_freeinodes_counter,
 142                                            count);
 143                 }
 144                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
 145                 return -EFSBADCRC;
 146         }
 147         set_buffer_verified(bh);
 148         ext4_unlock_group(sb, block_group);
 149         return 0;
 150 }
 151
 152 /*
 153  * Read the inode allocation bitmap for a given block_group, reading
 154  * into the specified slot in the superblock's bitmap cache.
 155  *
 156  * Return buffer_head of bitmap on success or NULL.
 157  */
 158 static struct buffer_head *
 159 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 160 {
 161         struct ext4_group_desc *desc;
 162         struct buffer_head *bh = NULL;
 163         ext4_fsblk_t bitmap_blk;
 164         int err;
 165
 166         desc = ext4_get_group_desc(sb, block_group, NULL);
 167         if (!desc)
 168                 return ERR_PTR(-EFSCORRUPTED);
 169
 170         bitmap_blk = ext4_inode_bitmap(sb, desc);
 171         bh = sb_getblk(sb, bitmap_blk);
 172         if (unlikely(!bh)) {
 173                 ext4_error(sb, "Cannot read inode bitmap - "
 174                             "block_group = %u, inode_bitmap = %llu",
 175                             block_group, bitmap_blk);
 176                 return ERR_PTR(-EIO);
 177         }
 178         if (bitmap_uptodate(bh))
 179                 goto verify;
 180
 181         lock_buffer(bh);
 182         if (bitmap_uptodate(bh)) {
 183                 unlock_buffer(bh);
 184                 goto verify;
 185         }
 186
 187         ext4_lock_group(sb, block_group);
 188         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 189                 err = ext4_init_inode_bitmap(sb, bh, block_group, desc);
 190                 set_bitmap_uptodate(bh);
 191                 set_buffer_uptodate(bh);
 192                 set_buffer_verified(bh);
 193                 ext4_unlock_group(sb, block_group);
 194                 unlock_buffer(bh);
 195                 if (err) {
 196                         ext4_error(sb, "Failed to init inode bitmap for group "
 197                                    "%u: %d", block_group, err);
 198                         goto out;
 199                 }
 200                 return bh;
 201         }
 202         ext4_unlock_group(sb, block_group);
 203
 204         if (buffer_uptodate(bh)) {
 205                 /*
 206                  * if not uninit if bh is uptodate,
 207                  * bitmap is also uptodate
 208                  */
 209                 set_bitmap_uptodate(bh);
 210                 unlock_buffer(bh);
 211                 goto verify;
 212         }
 213         /*
 214          * submit the buffer_head for reading
 215          */
 216         trace_ext4_load_inode_bitmap(sb, block_group);
 217         bh->b_end_io = ext4_end_bitmap_read;
 218         get_bh(bh);
 219         submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
 220         wait_on_buffer(bh);
 221         if (!buffer_uptodate(bh)) {
 222                 put_bh(bh);
 223                 ext4_error(sb, "Cannot read inode bitmap - "
 224                            "block_group = %u, inode_bitmap = %llu",
 225                            block_group, bitmap_blk);
 226                 return ERR_PTR(-EIO);
 227         }
 228
 229 verify:
 230         err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
 231         if (err)
 232                 goto out;
 233         return bh;
 234 out:
 235         put_bh(bh);
 236         return ERR_PTR(err);
 237 }
 238
 239 /*
 240  * NOTE! When we get the inode, we're the only people
 241  * that have access to it, and as such there are no
 242  * race conditions we have to worry about. The inode
 243  * is not on the hash-lists, and it cannot be reached
 244  * through the filesystem because the directory entry
 245  * has been deleted earlier.
 246  *
 247  * HOWEVER: we must make sure that we get no aliases,
 248  * which means that we have to call "clear_inode()"
 249  * _before_ we mark the inode not in use in the inode
 250  * bitmaps. Otherwise a newly created file might use
 251  * the same inode number (not actually the same pointer
 252  * though), and then we'd have two inodes sharing the
 253  * same inode number and space on the harddisk.
 254  */
 255 void ext4_free_inode(handle_t *handle, struct inode *inode)
 256 {
 257         struct super_block *sb = inode->i_sb;
 258         int is_directory;
 259         unsigned long ino;
 260         struct buffer_head *bitmap_bh = NULL;
 261         struct buffer_head *bh2;
 262         ext4_group_t block_group;
 263         unsigned long bit;
 264         struct ext4_group_desc *gdp;
 265         struct ext4_super_block *es;
 266         struct ext4_sb_info *sbi;
 267         int fatal = 0, err, count, cleared;
 268         struct ext4_group_info *grp;
 269
 270         if (!sb) {
 271                 printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
 272                        "nonexistent device\n", __func__, __LINE__);
 273                 return;
 274         }
 275         if (atomic_read(&inode->i_count) > 1) {
 276                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
 277                          __func__, __LINE__, inode->i_ino,
 278                          atomic_read(&inode->i_count));
 279                 return;
 280         }
 281         if (inode->i_nlink) {
 282                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
 283                          __func__, __LINE__, inode->i_ino, inode->i_nlink);
 284                 return;
 285         }
 286         sbi = EXT4_SB(sb);
 287
 288         ino = inode->i_ino;
 289         ext4_debug("freeing inode %lu\n", ino);
 290         trace_ext4_free_inode(inode);
 291
 292         /*
 293          * Note: we must free any quota before locking the superblock,
 294          * as writing the quota to disk may need the lock as well.
 295          */
 296         dquot_initialize(inode);
 297         ext4_xattr_delete_inode(handle, inode);
 298         dquot_free_inode(inode);
 299         dquot_drop(inode);
 300
 301         is_directory = S_ISDIR(inode->i_mode);
 302
 303         /* Do this BEFORE marking the inode not in use or returning an error */
 304         ext4_clear_inode(inode);
 305
 306         es = EXT4_SB(sb)->s_es;
 307         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 308                 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
 309                 goto error_return;
 310         }
 311         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 312         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 313         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 314         /* Don't bother if the inode bitmap is corrupt. */
 315         grp = ext4_get_group_info(sb, block_group);
 316         if (IS_ERR(bitmap_bh)) {
 317                 fatal = PTR_ERR(bitmap_bh);
 318                 bitmap_bh = NULL;
 319                 goto error_return;
 320         }
 321         if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
 322                 fatal = -EFSCORRUPTED;
 323                 goto error_return;
 324         }
 325
 326         BUFFER_TRACE(bitmap_bh, "get_write_access");
 327         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 328         if (fatal)
 329                 goto error_return;
 330
 331         fatal = -ESRCH;
 332         gdp = ext4_get_group_desc(sb, block_group, &bh2);
 333         if (gdp) {
 334                 BUFFER_TRACE(bh2, "get_write_access");
 335                 fatal = ext4_journal_get_write_access(handle, bh2);
 336         }
 337         ext4_lock_group(sb, block_group);
 338         cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
 339         if (fatal || !cleared) {
 340                 ext4_unlock_group(sb, block_group);
 341                 goto out;
 342         }
 343
 344         count = ext4_free_inodes_count(sb, gdp) + 1;
 345         ext4_free_inodes_set(sb, gdp, count);
 346         if (is_directory) {
 347                 count = ext4_used_dirs_count(sb, gdp) - 1;
 348                 ext4_used_dirs_set(sb, gdp, count);
 349                 percpu_counter_dec(&sbi->s_dirs_counter);
 350         }
 351         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
 352                                    EXT4_INODES_PER_GROUP(sb) / 8);
 353         ext4_group_desc_csum_set(sb, block_group, gdp);
 354         ext4_unlock_group(sb, block_group);
 355
 356         percpu_counter_inc(&sbi->s_freeinodes_counter);
 357         if (sbi->s_log_groups_per_flex) {
 358                 ext4_group_t f = ext4_flex_group(sbi, block_group);
 359
 360                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 361                 if (is_directory)
 362                         atomic_dec(&sbi->s_flex_groups[f].used_dirs);
 363         }
 364         BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 365         fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
 366 out:
 367         if (cleared) {
 368                 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 369                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 370                 if (!fatal)
 371                         fatal = err;
 372         } else {
 373                 ext4_error(sb, "bit already cleared for inode %lu", ino);
 374                 if (gdp && !EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 375                         int count;
 376                         count = ext4_free_inodes_count(sb, gdp);
 377                         percpu_counter_sub(&sbi->s_freeinodes_counter,
 378                                            count);
 379                 }
 380                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
 381         }
 382
 383 error_return:
 384         brelse(bitmap_bh);
 385         ext4_std_error(sb, fatal);
 386 }
 387
 388 struct orlov_stats {
 389         __u64 free_clusters;
 390         __u32 free_inodes;
 391         __u32 used_dirs;
 392 };
 393
 394 /*
 395  * Helper function for Orlov's allocator; returns critical information
 396  * for a particular block group or flex_bg.  If flex_size is 1, then g
 397  * is a block group number; otherwise it is flex_bg number.
 398  */
 399 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 400                             int flex_size, struct orlov_stats *stats)
 401 {
 402         struct ext4_group_desc *desc;
 403         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
 404
 405         if (flex_size > 1) {
 406                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
 407                 stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
 408                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
 409                 return;
 410         }
 411
 412         desc = ext4_get_group_desc(sb, g, NULL);
 413         if (desc) {
 414                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
 415                 stats->free_clusters = ext4_free_group_clusters(sb, desc);
 416                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
 417         } else {
 418                 stats->free_inodes = 0;
 419                 stats->free_clusters = 0;
 420                 stats->used_dirs = 0;
 421         }
 422 }
 423
 424 /*
 425  * Orlov's allocator for directories.
 426  *
 427  * We always try to spread first-level directories.
 428  *
 429  * If there are blockgroups with both free inodes and free blocks counts
 430  * not worse than average we return one with smallest directory count.
 431  * Otherwise we simply return a random group.
 432  *
 433  * For the rest rules look so:
 434  *
 435  * It's OK to put directory into a group unless
 436  * it has too many directories already (max_dirs) or
 437  * it has too few free inodes left (min_inodes) or
 438  * it has too few free blocks left (min_blocks) or
 439  * Parent's group is preferred, if it doesn't satisfy these
 440  * conditions we search cyclically through the rest. If none
 441  * of the groups look good we just look for a group with more
 442  * free inodes than average (starting at parent's group).
 443  */
 444
 445 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 446                             ext4_group_t *group, umode_t mode,
 447                             const struct qstr *qstr)
 448 {
 449         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 450         struct ext4_sb_info *sbi = EXT4_SB(sb);
 451         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 452         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 453         unsigned int freei, avefreei, grp_free;
 454         ext4_fsblk_t freeb, avefreec;
 455         unsigned int ndirs;
 456         int max_dirs, min_inodes;
 457         ext4_grpblk_t min_clusters;
 458         ext4_group_t i, grp, g, ngroups;
 459         struct ext4_group_desc *desc;
 460         struct orlov_stats stats;
 461         int flex_size = ext4_flex_bg_size(sbi);
 462         struct dx_hash_info hinfo;
 463
 464         ngroups = real_ngroups;
 465         if (flex_size > 1) {
 466                 ngroups = (real_ngroups + flex_size - 1) >>
 467                         sbi->s_log_groups_per_flex;
 468                 parent_group >>= sbi->s_log_groups_per_flex;
 469         }
 470
 471         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 472         avefreei = freei / ngroups;
 473         freeb = EXT4_C2B(sbi,
 474                 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
 475         avefreec = freeb;
 476         do_div(avefreec, ngroups);
 477         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 478
 479         if (S_ISDIR(mode) &&
 480             ((parent == d_inode(sb->s_root)) ||
 481              (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
 482                 int best_ndir = inodes_per_group;
 483                 int ret = -1;
 484
 485                 if (qstr) {
 486                         hinfo.hash_version = DX_HASH_HALF_MD4;
 487                         hinfo.seed = sbi->s_hash_seed;
 488                         ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
 489                         grp = hinfo.hash;
 490                 } else
 491                         grp = prandom_u32();
 492                 parent_group = (unsigned)grp % ngroups;
 493                 for (i = 0; i < ngroups; i++) {
 494                         g = (parent_group + i) % ngroups;
 495                         get_orlov_stats(sb, g, flex_size, &stats);
 496                         if (!stats.free_inodes)
 497                                 continue;
 498                         if (stats.used_dirs >= best_ndir)
 499                                 continue;
 500                         if (stats.free_inodes < avefreei)
 501                                 continue;
 502                         if (stats.free_clusters < avefreec)
 503                                 continue;
 504                         grp = g;
 505                         ret = 0;
 506                         best_ndir = stats.used_dirs;
 507                 }
 508                 if (ret)
 509                         goto fallback;
 510         found_flex_bg:
 511                 if (flex_size == 1) {
 512                         *group = grp;
 513                         return 0;
 514                 }
 515
 516                 /*
 517                  * We pack inodes at the beginning of the flexgroup's
 518                  * inode tables.  Block allocation decisions will do
 519                  * something similar, although regular files will
 520                  * start at 2nd block group of the flexgroup.  See
 521                  * ext4_ext_find_goal() and ext4_find_near().
 522                  */
 523                 grp *= flex_size;
 524                 for (i = 0; i < flex_size; i++) {
 525                         if (grp+i >= real_ngroups)
 526                                 break;
 527                         desc = ext4_get_group_desc(sb, grp+i, NULL);
 528                         if (desc && ext4_free_inodes_count(sb, desc)) {
 529                                 *group = grp+i;
 530                                 return 0;
 531                         }
 532                 }
 533                 goto fallback;
 534         }
 535
 536         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 537         min_inodes = avefreei - inodes_per_group*flex_size / 4;
 538         if (min_inodes < 1)
 539                 min_inodes = 1;
 540         min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
 541
 542         /*
 543          * Start looking in the flex group where we last allocated an
 544          * inode for this parent directory
 545          */
 546         if (EXT4_I(parent)->i_last_alloc_group != ~0) {
 547                 parent_group = EXT4_I(parent)->i_last_alloc_group;
 548                 if (flex_size > 1)
 549                         parent_group >>= sbi->s_log_groups_per_flex;
 550         }
 551
 552         for (i = 0; i < ngroups; i++) {
 553                 grp = (parent_group + i) % ngroups;
 554                 get_orlov_stats(sb, grp, flex_size, &stats);
 555                 if (stats.used_dirs >= max_dirs)
 556                         continue;
 557                 if (stats.free_inodes < min_inodes)
 558                         continue;
 559                 if (stats.free_clusters < min_clusters)
 560                         continue;
 561                 goto found_flex_bg;
 562         }
 563
 564 fallback:
 565         ngroups = real_ngroups;
 566         avefreei = freei / ngroups;
 567 fallback_retry:
 568         parent_group = EXT4_I(parent)->i_block_group;
 569         for (i = 0; i < ngroups; i++) {
 570                 grp = (parent_group + i) % ngroups;
 571                 desc = ext4_get_group_desc(sb, grp, NULL);
 572                 if (desc) {
 573                         grp_free = ext4_free_inodes_count(sb, desc);
 574                         if (grp_free && grp_free >= avefreei) {
 575                                 *group = grp;
 576                                 return 0;
 577                         }
 578                 }
 579         }
 580
 581         if (avefreei) {
 582                 /*
 583                  * The free-inodes counter is approximate, and for really small
 584                  * filesystems the above test can fail to find any blockgroups
 585                  */
 586                 avefreei = 0;
 587                 goto fallback_retry;
 588         }
 589
 590         return -1;
 591 }
 592
 593 static int find_group_other(struct super_block *sb, struct inode *parent,
 594                             ext4_group_t *group, umode_t mode)
 595 {
 596         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 597         ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
 598         struct ext4_group_desc *desc;
 599         int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
 600
 601         /*
 602          * Try to place the inode is the same flex group as its
 603          * parent.  If we can't find space, use the Orlov algorithm to
 604          * find another flex group, and store that information in the
 605          * parent directory's inode information so that use that flex
 606          * group for future allocations.
 607          */
 608         if (flex_size > 1) {
 609                 int retry = 0;
 610
 611         try_again:
 612                 parent_group &= ~(flex_size-1);
 613                 last = parent_group + flex_size;
 614                 if (last > ngroups)
 615                         last = ngroups;
 616                 for  (i = parent_group; i < last; i++) {
 617                         desc = ext4_get_group_desc(sb, i, NULL);
 618                         if (desc && ext4_free_inodes_count(sb, desc)) {
 619                                 *group = i;
 620                                 return 0;
 621                         }
 622                 }
 623                 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
 624                         retry = 1;
 625                         parent_group = EXT4_I(parent)->i_last_alloc_group;
 626                         goto try_again;
 627                 }
 628                 /*
 629                  * If this didn't work, use the Orlov search algorithm
 630                  * to find a new flex group; we pass in the mode to
 631                  * avoid the topdir algorithms.
 632                  */
 633                 *group = parent_group + flex_size;
 634                 if (*group > ngroups)
 635                         *group = 0;
 636                 return find_group_orlov(sb, parent, group, mode, NULL);
 637         }
 638
 639         /*
 640          * Try to place the inode in its parent directory
 641          */
 642         *group = parent_group;
 643         desc = ext4_get_group_desc(sb, *group, NULL);
 644         if (desc && ext4_free_inodes_count(sb, desc) &&
 645             ext4_free_group_clusters(sb, desc))
 646                 return 0;
 647
 648         /*
 649          * We're going to place this inode in a different blockgroup from its
 650          * parent.  We want to cause files in a common directory to all land in
 651          * the same blockgroup.  But we want files which are in a different
 652          * directory which shares a blockgroup with our parent to land in a
 653          * different blockgroup.
 654          *
 655          * So add our directory's i_ino into the starting point for the hash.
 656          */
 657         *group = (*group + parent->i_ino) % ngroups;
 658
 659         /*
 660          * Use a quadratic hash to find a group with a free inode and some free
 661          * blocks.
 662          */
 663         for (i = 1; i < ngroups; i <<= 1) {
 664                 *group += i;
 665                 if (*group >= ngroups)
 666                         *group -= ngroups;
 667                 desc = ext4_get_group_desc(sb, *group, NULL);
 668                 if (desc && ext4_free_inodes_count(sb, desc) &&
 669                     ext4_free_group_clusters(sb, desc))
 670                         return 0;
 671         }
 672
 673         /*
 674          * That failed: try linear search for a free inode, even if that group
 675          * has no free blocks.
 676          */
 677         *group = parent_group;
 678         for (i = 0; i < ngroups; i++) {
 679                 if (++*group >= ngroups)
 680                         *group = 0;
 681                 desc = ext4_get_group_desc(sb, *group, NULL);
 682                 if (desc && ext4_free_inodes_count(sb, desc))
 683                         return 0;
 684         }
 685
 686         return -1;
 687 }
 688
 689 /*
 690  * In no journal mode, if an inode has recently been deleted, we want
 691  * to avoid reusing it until we're reasonably sure the inode table
 692  * block has been written back to disk.  (Yes, these values are
 693  * somewhat arbitrary...)
 694  */
 695 #define RECENTCY_MIN    5
 696 #define RECENTCY_DIRTY  30
 697
 698 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
 699 {
 700         struct ext4_group_desc  *gdp;
 701         struct ext4_inode       *raw_inode;
 702         struct buffer_head      *bh;
 703         unsigned long           dtime, now;
 704         int     inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
 705         int     offset, ret = 0, recentcy = RECENTCY_MIN;
 706
 707         gdp = ext4_get_group_desc(sb, group, NULL);
 708         if (unlikely(!gdp))
 709                 return 0;
 710
 711         bh = sb_getblk(sb, ext4_inode_table(sb, gdp) +
 712                        (ino / inodes_per_block));
 713         if (unlikely(!bh) || !buffer_uptodate(bh))
 714                 /*
 715                  * If the block is not in the buffer cache, then it
 716                  * must have been written out.
 717                  */
 718                 goto out;
 719
 720         offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
 721         raw_inode = (struct ext4_inode *) (bh->b_data + offset);
 722         dtime = le32_to_cpu(raw_inode->i_dtime);
 723         now = get_seconds();
 724         if (buffer_dirty(bh))
 725                 recentcy += RECENTCY_DIRTY;
 726
 727         if (dtime && (dtime < now) && (now < dtime + recentcy))
 728                 ret = 1;
 729 out:
 730         brelse(bh);
 731         return ret;
 732 }
 733
 734 /*
 735  * There are two policies for allocating an inode.  If the new inode is
 736  * a directory, then a forward search is made for a block group with both
 737  * free space and a low directory-to-inode ratio; if that fails, then of
 738  * the groups with above-average free space, that group with the fewest
 739  * directories already is chosen.
 740  *
 741  * For other inodes, search forward from the parent directory's block
 742  * group to find a free inode.
 743  */
 744 struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 745                                umode_t mode, const struct qstr *qstr,
 746                                __u32 goal, uid_t *owner, int handle_type,
 747                                unsigned int line_no, int nblocks)
 748 {
 749         struct super_block *sb;
 750         struct buffer_head *inode_bitmap_bh = NULL;
 751         struct buffer_head *group_desc_bh;
 752         ext4_group_t ngroups, group = 0;
 753         unsigned long ino = 0;
 754         struct inode *inode;
 755         struct ext4_group_desc *gdp = NULL;
 756         struct ext4_inode_info *ei;
 757         struct ext4_sb_info *sbi;
 758         int ret2, err;
 759         struct inode *ret;
 760         ext4_group_t i;
 761         ext4_group_t flex_group;
 762         struct ext4_group_info *grp;
 763         int encrypt = 0;
 764
 765         /* Cannot create files in a deleted directory */
 766         if (!dir || !dir->i_nlink)
 767                 return ERR_PTR(-EPERM);
 768
 769         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
 770                 return ERR_PTR(-EIO);
 771
 772         if ((ext4_encrypted_inode(dir) ||
 773              DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb))) &&
 774             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
 775                 err = fscrypt_get_encryption_info(dir);
 776                 if (err)
 777                         return ERR_PTR(err);
 778                 if (!fscrypt_has_encryption_key(dir))
 779                         return ERR_PTR(-ENOKEY);
 780                 if (!handle)
 781                         nblocks += EXT4_DATA_TRANS_BLOCKS(dir->i_sb);
 782                 encrypt = 1;
 783         }
 784
 785         sb = dir->i_sb;
 786         ngroups = ext4_get_groups_count(sb);
 787         trace_ext4_request_inode(dir, mode);
 788         inode = new_inode(sb);
 789         if (!inode)
 790                 return ERR_PTR(-ENOMEM);
 791         ei = EXT4_I(inode);
 792         sbi = EXT4_SB(sb);
 793
 794         /*
 795          * Initialize owners and quota early so that we don't have to account
 796          * for quota initialization worst case in standard inode creating
 797          * transaction
 798          */
 799         if (owner) {
 800                 inode->i_mode = mode;
 801                 i_uid_write(inode, owner[0]);
 802                 i_gid_write(inode, owner[1]);
 803         } else if (test_opt(sb, GRPID)) {
 804                 inode->i_mode = mode;
 805                 inode->i_uid = current_fsuid();
 806                 inode->i_gid = dir->i_gid;
 807         } else
 808                 inode_init_owner(inode, dir, mode);
 809
 810         if (ext4_has_feature_project(sb) &&
 811             ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
 812                 ei->i_projid = EXT4_I(dir)->i_projid;
 813         else
 814                 ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
 815
 816         err = dquot_initialize(inode);
 817         if (err)
 818                 goto out;
 819
 820         if (!goal)
 821                 goal = sbi->s_inode_goal;
 822
 823         if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
 824                 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
 825                 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
 826                 ret2 = 0;
 827                 goto got_group;
 828         }
 829
 830         if (S_ISDIR(mode))
 831                 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
 832         else
 833                 ret2 = find_group_other(sb, dir, &group, mode);
 834
 835 got_group:
 836         EXT4_I(dir)->i_last_alloc_group = group;
 837         err = -ENOSPC;
 838         if (ret2 == -1)
 839                 goto out;
 840
 841         /*
 842          * Normally we will only go through one pass of this loop,
 843          * unless we get unlucky and it turns out the group we selected
 844          * had its last inode grabbed by someone else.
 845          */
 846         for (i = 0; i < ngroups; i++, ino = 0) {
 847                 err = -EIO;
 848
 849                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 850                 if (!gdp)
 851                         goto out;
 852
 853                 /*
 854                  * Check free inodes count before loading bitmap.
 855                  */
 856                 if (ext4_free_inodes_count(sb, gdp) == 0) {
 857                         if (++group == ngroups)
 858                                 group = 0;
 859                         continue;
 860                 }
 861
 862                 grp = ext4_get_group_info(sb, group);
 863                 /* Skip groups with already-known suspicious inode tables */
 864                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 865                         if (++group == ngroups)
 866                                 group = 0;
 867                         continue;
 868                 }
 869
 870                 brelse(inode_bitmap_bh);
 871                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 872                 /* Skip groups with suspicious inode tables */
 873                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
 874                     IS_ERR(inode_bitmap_bh)) {
 875                         inode_bitmap_bh = NULL;
 876                         if (++group == ngroups)
 877                                 group = 0;
 878                         continue;
 879                 }
 880
 881 repeat_in_this_group:
 882                 ino = ext4_find_next_zero_bit((unsigned long *)
 883                                               inode_bitmap_bh->b_data,
 884                                               EXT4_INODES_PER_GROUP(sb), ino);
 885                 if (ino >= EXT4_INODES_PER_GROUP(sb))
 886                         goto next_group;
 887                 if (group == 0 && (ino+1) < EXT4_FIRST_INO(sb)) {
 888                         ext4_error(sb, "reserved inode found cleared - "
 889                                    "inode=%lu", ino + 1);
 890                         continue;
 891                 }
 892                 if ((EXT4_SB(sb)->s_journal == NULL) &&
 893                     recently_deleted(sb, group, ino)) {
 894                         ino++;
 895                         goto next_inode;
 896                 }
 897                 if (!handle) {
 898                         BUG_ON(nblocks <= 0);
 899                         handle = __ext4_journal_start_sb(dir->i_sb, line_no,
 900                                                          handle_type, nblocks,
 901                                                          0);
 902                         if (IS_ERR(handle)) {
 903                                 err = PTR_ERR(handle);
 904                                 ext4_std_error(sb, err);
 905                                 goto out;
 906                         }
 907                 }
 908                 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 909                 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
 910                 if (err) {
 911                         ext4_std_error(sb, err);
 912                         goto out;
 913                 }
 914                 ext4_lock_group(sb, group);
 915                 ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
 916                 ext4_unlock_group(sb, group);
 917                 ino++;          /* the inode bitmap is zero-based */
 918                 if (!ret2)
 919                         goto got; /* we grabbed the inode! */
 920 next_inode:
 921                 if (ino < EXT4_INODES_PER_GROUP(sb))
 922                         goto repeat_in_this_group;
 923 next_group:
 924                 if (++group == ngroups)
 925                         group = 0;
 926         }
 927         err = -ENOSPC;
 928         goto out;
 929
 930 got:
 931         BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
 932         err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
 933         if (err) {
 934                 ext4_std_error(sb, err);
 935                 goto out;
 936         }
 937
 938         BUFFER_TRACE(group_desc_bh, "get_write_access");
 939         err = ext4_journal_get_write_access(handle, group_desc_bh);
 940         if (err) {
 941                 ext4_std_error(sb, err);
 942                 goto out;
 943         }
 944
 945         /* We may have to initialize the block bitmap if it isn't already */
 946         if (ext4_has_group_desc_csum(sb) &&
 947             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 948                 struct buffer_head *block_bitmap_bh;
 949
 950                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 951                 if (IS_ERR(block_bitmap_bh)) {
 952                         err = PTR_ERR(block_bitmap_bh);
 953                         goto out;
 954                 }
 955                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 956                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 957                 if (err) {
 958                         brelse(block_bitmap_bh);
 959                         ext4_std_error(sb, err);
 960                         goto out;
 961                 }
 962
 963                 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
 964                 err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
 965
 966                 /* recheck and clear flag under lock if we still need to */
 967                 ext4_lock_group(sb, group);
 968                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 969                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 970                         ext4_free_group_clusters_set(sb, gdp,
 971                                 ext4_free_clusters_after_init(sb, group, gdp));
 972                         ext4_block_bitmap_csum_set(sb, group, gdp,
 973                                                    block_bitmap_bh);
 974                         ext4_group_desc_csum_set(sb, group, gdp);
 975                 }
 976                 ext4_unlock_group(sb, group);
 977                 brelse(block_bitmap_bh);
 978
 979                 if (err) {
 980                         ext4_std_error(sb, err);
 981                         goto out;
 982                 }
 983         }
 984
 985         /* Update the relevant bg descriptor fields */
 986         if (ext4_has_group_desc_csum(sb)) {
 987                 int free;
 988                 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
 989
 990                 down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
 991                 ext4_lock_group(sb, group); /* while we modify the bg desc */
 992                 free = EXT4_INODES_PER_GROUP(sb) -
 993                         ext4_itable_unused_count(sb, gdp);
 994                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 995                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 996                         free = 0;
 997                 }
 998                 /*
 999                  * Check the relative inode number against the last used
1000                  * relative inode number in this group. if it is greater
1001                  * we need to update the bg_itable_unused count
1002                  */
1003                 if (ino > free)
1004                         ext4_itable_unused_set(sb, gdp,
1005                                         (EXT4_INODES_PER_GROUP(sb) - ino));
1006                 up_read(&grp->alloc_sem);
1007         } else {
1008                 ext4_lock_group(sb, group);
1009         }
1010
1011         ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1012         if (S_ISDIR(mode)) {
1013                 ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1014                 if (sbi->s_log_groups_per_flex) {
1015                         ext4_group_t f = ext4_flex_group(sbi, group);
1016
1017                         atomic_inc(&sbi->s_flex_groups[f].used_dirs);
1018                 }
1019         }
1020         if (ext4_has_group_desc_csum(sb)) {
1021                 ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1022                                            EXT4_INODES_PER_GROUP(sb) / 8);
1023                 ext4_group_desc_csum_set(sb, group, gdp);
1024         }
1025         ext4_unlock_group(sb, group);
1026
1027         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1028         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1029         if (err) {
1030                 ext4_std_error(sb, err);
1031                 goto out;
1032         }
1033
1034         percpu_counter_dec(&sbi->s_freeinodes_counter);
1035         if (S_ISDIR(mode))
1036                 percpu_counter_inc(&sbi->s_dirs_counter);
1037
1038         if (sbi->s_log_groups_per_flex) {
1039                 flex_group = ext4_flex_group(sbi, group);
1040                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
1041         }
1042
1043         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1044         /* This is the optimal IO size (for stat), not the fs block size */
1045         inode->i_blocks = 0;
1046         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
1047                                                        current_time(inode);
1048
1049         memset(ei->i_data, 0, sizeof(ei->i_data));
1050         ei->i_dir_start_lookup = 0;
1051         ei->i_disksize = 0;
1052
1053         /* Don't inherit extent flag from directory, amongst others. */
1054         ei->i_flags =
1055                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1056         ei->i_file_acl = 0;
1057         ei->i_dtime = 0;
1058         ei->i_block_group = group;
1059         ei->i_last_alloc_group = ~0;
1060
1061         ext4_set_inode_flags(inode);
1062         if (IS_DIRSYNC(inode))
1063                 ext4_handle_sync(handle);
1064         if (insert_inode_locked(inode) < 0) {
1065                 /*
1066                  * Likely a bitmap corruption causing inode to be allocated
1067                  * twice.
1068                  */
1069                 err = -EIO;
1070                 ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1071                            inode->i_ino);
1072                 goto out;
1073         }
1074         spin_lock(&sbi->s_next_gen_lock);
1075         inode->i_generation = sbi->s_next_generation++;
1076         spin_unlock(&sbi->s_next_gen_lock);
1077
1078         /* Precompute checksum seed for inode metadata */
1079         if (ext4_has_metadata_csum(sb)) {
1080                 __u32 csum;
1081                 __le32 inum = cpu_to_le32(inode->i_ino);
1082                 __le32 gen = cpu_to_le32(inode->i_generation);
1083                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1084                                    sizeof(inum));
1085                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1086                                               sizeof(gen));
1087         }
1088
1089         ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1090         ext4_set_inode_state(inode, EXT4_STATE_NEW);
1091
1092         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
1093         ei->i_inline_off = 0;
1094         if (ext4_has_feature_inline_data(sb))
1095                 ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1096         ret = inode;
1097         err = dquot_alloc_inode(inode);
1098         if (err)
1099                 goto fail_drop;
1100
1101         /*
1102          * Since the encryption xattr will always be unique, create it first so
1103          * that it's less likely to end up in an external xattr block and
1104          * prevent its deduplication.
1105          */
1106         if (encrypt) {
1107                 err = fscrypt_inherit_context(dir, inode, handle, true);
1108                 if (err)
1109                         goto fail_free_drop;
1110         }
1111
1112         err = ext4_init_acl(handle, inode, dir);
1113         if (err)
1114                 goto fail_free_drop;
1115
1116         err = ext4_init_security(handle, inode, dir, qstr);
1117         if (err)
1118                 goto fail_free_drop;
1119
1120         if (ext4_has_feature_extents(sb)) {
1121                 /* set extent flag only for directory, file and normal symlink*/
1122                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1123                         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1124                         ext4_ext_tree_init(handle, inode);
1125                 }
1126         }
1127
1128         if (ext4_handle_valid(handle)) {
1129                 ei->i_sync_tid = handle->h_transaction->t_tid;
1130                 ei->i_datasync_tid = handle->h_transaction->t_tid;
1131         }
1132
1133         err = ext4_mark_inode_dirty(handle, inode);
1134         if (err) {
1135                 ext4_std_error(sb, err);
1136                 goto fail_free_drop;
1137         }
1138
1139         ext4_debug("allocating inode %lu\n", inode->i_ino);
1140         trace_ext4_allocate_inode(inode, dir, mode);
1141         brelse(inode_bitmap_bh);
1142         return ret;
1143
1144 fail_free_drop:
1145         dquot_free_inode(inode);
1146 fail_drop:
1147         clear_nlink(inode);
1148         unlock_new_inode(inode);
1149 out:
1150         dquot_drop(inode);
1151         inode->i_flags |= S_NOQUOTA;
1152         iput(inode);
1153         brelse(inode_bitmap_bh);
1154         return ERR_PTR(err);
1155 }
1156
1157 /* Verify that we are loading a valid orphan from disk */
1158 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1159 {
1160         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1161         ext4_group_t block_group;
1162         int bit;
1163         struct buffer_head *bitmap_bh = NULL;
1164         struct inode *inode = NULL;
1165         int err = -EFSCORRUPTED;
1166
1167         if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
1168                 goto bad_orphan;
1169
1170         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1171         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1172         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1173         if (IS_ERR(bitmap_bh)) {
1174                 ext4_error(sb, "inode bitmap error %ld for orphan %lu",
1175                            ino, PTR_ERR(bitmap_bh));
1176                 return (struct inode *) bitmap_bh;
1177         }
1178
1179         /* Having the inode bit set should be a 100% indicator that this
1180          * is a valid orphan (no e2fsck run on fs).  Orphans also include
1181          * inodes that were being truncated, so we can't check i_nlink==0.
1182          */
1183         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1184                 goto bad_orphan;
1185
1186         inode = ext4_iget(sb, ino);
1187         if (IS_ERR(inode)) {
1188                 err = PTR_ERR(inode);
1189                 ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
1190                            ino, err);
1191                 return inode;
1192         }
1193
1194         /*
1195          * If the orphans has i_nlinks > 0 then it should be able to
1196          * be truncated, otherwise it won't be removed from the orphan
1197          * list during processing and an infinite loop will result.
1198          * Similarly, it must not be a bad inode.
1199          */
1200         if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
1201             is_bad_inode(inode))
1202                 goto bad_orphan;
1203
1204         if (NEXT_ORPHAN(inode) > max_ino)
1205                 goto bad_orphan;
1206         brelse(bitmap_bh);
1207         return inode;
1208
1209 bad_orphan:
1210         ext4_error(sb, "bad orphan inode %lu", ino);
1211         if (bitmap_bh)
1212                 printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1213                        bit, (unsigned long long)bitmap_bh->b_blocknr,
1214                        ext4_test_bit(bit, bitmap_bh->b_data));
1215         if (inode) {
1216                 printk(KERN_ERR "is_bad_inode(inode)=%d\n",
1217                        is_bad_inode(inode));
1218                 printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
1219                        NEXT_ORPHAN(inode));
1220                 printk(KERN_ERR "max_ino=%lu\n", max_ino);
1221                 printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
1222                 /* Avoid freeing blocks if we got a bad deleted inode */
1223                 if (inode->i_nlink == 0)
1224                         inode->i_blocks = 0;
1225                 iput(inode);
1226         }
1227         brelse(bitmap_bh);
1228         return ERR_PTR(err);
1229 }
1230
1231 unsigned long ext4_count_free_inodes(struct super_block *sb)
1232 {
1233         unsigned long desc_count;
1234         struct ext4_group_desc *gdp;
1235         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1236 #ifdef EXT4FS_DEBUG
1237         struct ext4_super_block *es;
1238         unsigned long bitmap_count, x;
1239         struct buffer_head *bitmap_bh = NULL;
1240
1241         es = EXT4_SB(sb)->s_es;
1242         desc_count = 0;
1243         bitmap_count = 0;
1244         gdp = NULL;
1245         for (i = 0; i < ngroups; i++) {
1246                 gdp = ext4_get_group_desc(sb, i, NULL);
1247                 if (!gdp)
1248                         continue;
1249                 desc_count += ext4_free_inodes_count(sb, gdp);
1250                 brelse(bitmap_bh);
1251                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1252                 if (IS_ERR(bitmap_bh)) {
1253                         bitmap_bh = NULL;
1254                         continue;
1255                 }
1256
1257                 x = ext4_count_free(bitmap_bh->b_data,
1258                                     EXT4_INODES_PER_GROUP(sb) / 8);
1259                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1260                         (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1261                 bitmap_count += x;
1262         }
1263         brelse(bitmap_bh);
1264         printk(KERN_DEBUG "ext4_count_free_inodes: "
1265                "stored = %u, computed = %lu, %lu\n",
1266                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1267         return desc_count;
1268 #else
1269         desc_count = 0;
1270         for (i = 0; i < ngroups; i++) {
1271                 gdp = ext4_get_group_desc(sb, i, NULL);
1272                 if (!gdp)
1273                         continue;
1274                 desc_count += ext4_free_inodes_count(sb, gdp);
1275                 cond_resched();
1276         }
1277         return desc_count;
1278 #endif
1279 }
1280
1281 /* Called at mount-time, super-block is locked */
1282 unsigned long ext4_count_dirs(struct super_block * sb)
1283 {
1284         unsigned long count = 0;
1285         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1286
1287         for (i = 0; i < ngroups; i++) {
1288                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1289                 if (!gdp)
1290                         continue;
1291                 count += ext4_used_dirs_count(sb, gdp);
1292         }
1293         return count;
1294 }
1295
1296 /*
1297  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1298  * inode table. Must be called without any spinlock held. The only place
1299  * where it is called from on active part of filesystem is ext4lazyinit
1300  * thread, so we do not need any special locks, however we have to prevent
1301  * inode allocation from the current group, so we take alloc_sem lock, to
1302  * block ext4_new_inode() until we are finished.
1303  */
1304 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1305                                  int barrier)
1306 {
1307         struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1308         struct ext4_sb_info *sbi = EXT4_SB(sb);
1309         struct ext4_group_desc *gdp = NULL;
1310         struct buffer_head *group_desc_bh;
1311         handle_t *handle;
1312         ext4_fsblk_t blk;
1313         int num, ret = 0, used_blks = 0;
1314
1315         /* This should not happen, but just to be sure check this */
1316         if (sb->s_flags & MS_RDONLY) {
1317                 ret = 1;
1318                 goto out;
1319         }
1320
1321         gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1322         if (!gdp)
1323                 goto out;
1324
1325         /*
1326          * We do not need to lock this, because we are the only one
1327          * handling this flag.
1328          */
1329         if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1330                 goto out;
1331
1332         handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1333         if (IS_ERR(handle)) {
1334                 ret = PTR_ERR(handle);
1335                 goto out;
1336         }
1337
1338         down_write(&grp->alloc_sem);
1339         /*
1340          * If inode bitmap was already initialized there may be some
1341          * used inodes so we need to skip blocks with used inodes in
1342          * inode table.
1343          */
1344         if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1345                 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1346                             ext4_itable_unused_count(sb, gdp)),
1347                             sbi->s_inodes_per_block);
1348
1349         if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1350                 ext4_error(sb, "Something is wrong with group %u: "
1351                            "used itable blocks: %d; "
1352                            "itable unused count: %u",
1353                            group, used_blks,
1354                            ext4_itable_unused_count(sb, gdp));
1355                 ret = 1;
1356                 goto err_out;
1357         }
1358
1359         blk = ext4_inode_table(sb, gdp) + used_blks;
1360         num = sbi->s_itb_per_group - used_blks;
1361
1362         BUFFER_TRACE(group_desc_bh, "get_write_access");
1363         ret = ext4_journal_get_write_access(handle,
1364                                             group_desc_bh);
1365         if (ret)
1366                 goto err_out;
1367
1368         /*
1369          * Skip zeroout if the inode table is full. But we set the ZEROED
1370          * flag anyway, because obviously, when it is full it does not need
1371          * further zeroing.
1372          */
1373         if (unlikely(num == 0))
1374                 goto skip_zeroout;
1375
1376         ext4_debug("going to zero out inode table in group %d\n",
1377                    group);
1378         ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1379         if (ret < 0)
1380                 goto err_out;
1381         if (barrier)
1382                 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1383
1384 skip_zeroout:
1385         ext4_lock_group(sb, group);
1386         gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1387         ext4_group_desc_csum_set(sb, group, gdp);
1388         ext4_unlock_group(sb, group);
1389
1390         BUFFER_TRACE(group_desc_bh,
1391                      "call ext4_handle_dirty_metadata");
1392         ret = ext4_handle_dirty_metadata(handle, NULL,
1393                                          group_desc_bh);
1394
1395 err_out:
1396         up_write(&grp->alloc_sem);
1397         ext4_journal_stop(handle);
1398 out:
1399         return ret;
1400 }