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                 grp = ext4_get_group_info(sb, block_group);
  80                 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
  81                         percpu_counter_sub(&sbi->s_freeclusters_counter,
  82                                            grp->bb_free);
  83                 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
  84                 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
  85                         int count;
  86                         count = ext4_free_inodes_count(sb, gdp);
  87                         percpu_counter_sub(&sbi->s_freeinodes_counter,
  88                                            count);
  89                 }
  90                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
  91                 return -EFSBADCRC;
  92         }
  93
  94         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
  95         ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
  96                         bh->b_data);
  97         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
  98                                    EXT4_INODES_PER_GROUP(sb) / 8);
  99         ext4_group_desc_csum_set(sb, block_group, gdp);
 100
 101         return 0;
 102 }
 103
 104 void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
 105 {
 106         if (uptodate) {
 107                 set_buffer_uptodate(bh);
 108                 set_bitmap_uptodate(bh);
 109         }
 110         unlock_buffer(bh);
 111         put_bh(bh);
 112 }
 113
 114 static int ext4_validate_inode_bitmap(struct super_block *sb,
 115                                       struct ext4_group_desc *desc,
 116                                       ext4_group_t block_group,
 117                                       struct buffer_head *bh)
 118 {
 119         ext4_fsblk_t    blk;
 120         struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
 121         struct ext4_sb_info *sbi = EXT4_SB(sb);
 122
 123         if (buffer_verified(bh))
 124                 return 0;
 125         if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
 126                 return -EFSCORRUPTED;
 127
 128         ext4_lock_group(sb, block_group);
 129         blk = ext4_inode_bitmap(sb, desc);
 130         if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
 131                                            EXT4_INODES_PER_GROUP(sb) / 8)) {
 132                 ext4_unlock_group(sb, block_group);
 133                 ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
 134                            "inode_bitmap = %llu", block_group, blk);
 135                 grp = ext4_get_group_info(sb, block_group);
 136                 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 137                         int count;
 138                         count = ext4_free_inodes_count(sb, desc);
 139                         percpu_counter_sub(&sbi->s_freeinodes_counter,
 140                                            count);
 141                 }
 142                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
 143                 return -EFSBADCRC;
 144         }
 145         set_buffer_verified(bh);
 146         ext4_unlock_group(sb, block_group);
 147         return 0;
 148 }
 149
 150 /*
 151  * Read the inode allocation bitmap for a given block_group, reading
 152  * into the specified slot in the superblock's bitmap cache.
 153  *
 154  * Return buffer_head of bitmap on success or NULL.
 155  */
 156 static struct buffer_head *
 157 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 158 {
 159         struct ext4_group_desc *desc;
 160         struct buffer_head *bh = NULL;
 161         ext4_fsblk_t bitmap_blk;
 162         int err;
 163
 164         desc = ext4_get_group_desc(sb, block_group, NULL);
 165         if (!desc)
 166                 return ERR_PTR(-EFSCORRUPTED);
 167
 168         bitmap_blk = ext4_inode_bitmap(sb, desc);
 169         bh = sb_getblk(sb, bitmap_blk);
 170         if (unlikely(!bh)) {
 171                 ext4_error(sb, "Cannot read inode bitmap - "
 172                             "block_group = %u, inode_bitmap = %llu",
 173                             block_group, bitmap_blk);
 174                 return ERR_PTR(-EIO);
 175         }
 176         if (bitmap_uptodate(bh))
 177                 goto verify;
 178
 179         lock_buffer(bh);
 180         if (bitmap_uptodate(bh)) {
 181                 unlock_buffer(bh);
 182                 goto verify;
 183         }
 184
 185         ext4_lock_group(sb, block_group);
 186         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 187                 err = ext4_init_inode_bitmap(sb, bh, block_group, desc);
 188                 set_bitmap_uptodate(bh);
 189                 set_buffer_uptodate(bh);
 190                 set_buffer_verified(bh);
 191                 ext4_unlock_group(sb, block_group);
 192                 unlock_buffer(bh);
 193                 if (err) {
 194                         ext4_error(sb, "Failed to init inode bitmap for group "
 195                                    "%u: %d", block_group, err);
 196                         goto out;
 197                 }
 198                 return bh;
 199         }
 200         ext4_unlock_group(sb, block_group);
 201
 202         if (buffer_uptodate(bh)) {
 203                 /*
 204                  * if not uninit if bh is uptodate,
 205                  * bitmap is also uptodate
 206                  */
 207                 set_bitmap_uptodate(bh);
 208                 unlock_buffer(bh);
 209                 goto verify;
 210         }
 211         /*
 212          * submit the buffer_head for reading
 213          */
 214         trace_ext4_load_inode_bitmap(sb, block_group);
 215         bh->b_end_io = ext4_end_bitmap_read;
 216         get_bh(bh);
 217         submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
 218         wait_on_buffer(bh);
 219         if (!buffer_uptodate(bh)) {
 220                 put_bh(bh);
 221                 ext4_error(sb, "Cannot read inode bitmap - "
 222                            "block_group = %u, inode_bitmap = %llu",
 223                            block_group, bitmap_blk);
 224                 return ERR_PTR(-EIO);
 225         }
 226
 227 verify:
 228         err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
 229         if (err)
 230                 goto out;
 231         return bh;
 232 out:
 233         put_bh(bh);
 234         return ERR_PTR(err);
 235 }
 236
 237 /*
 238  * NOTE! When we get the inode, we're the only people
 239  * that have access to it, and as such there are no
 240  * race conditions we have to worry about. The inode
 241  * is not on the hash-lists, and it cannot be reached
 242  * through the filesystem because the directory entry
 243  * has been deleted earlier.
 244  *
 245  * HOWEVER: we must make sure that we get no aliases,
 246  * which means that we have to call "clear_inode()"
 247  * _before_ we mark the inode not in use in the inode
 248  * bitmaps. Otherwise a newly created file might use
 249  * the same inode number (not actually the same pointer
 250  * though), and then we'd have two inodes sharing the
 251  * same inode number and space on the harddisk.
 252  */
 253 void ext4_free_inode(handle_t *handle, struct inode *inode)
 254 {
 255         struct super_block *sb = inode->i_sb;
 256         int is_directory;
 257         unsigned long ino;
 258         struct buffer_head *bitmap_bh = NULL;
 259         struct buffer_head *bh2;
 260         ext4_group_t block_group;
 261         unsigned long bit;
 262         struct ext4_group_desc *gdp;
 263         struct ext4_super_block *es;
 264         struct ext4_sb_info *sbi;
 265         int fatal = 0, err, count, cleared;
 266         struct ext4_group_info *grp;
 267
 268         if (!sb) {
 269                 printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
 270                        "nonexistent device\n", __func__, __LINE__);
 271                 return;
 272         }
 273         if (atomic_read(&inode->i_count) > 1) {
 274                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
 275                          __func__, __LINE__, inode->i_ino,
 276                          atomic_read(&inode->i_count));
 277                 return;
 278         }
 279         if (inode->i_nlink) {
 280                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
 281                          __func__, __LINE__, inode->i_ino, inode->i_nlink);
 282                 return;
 283         }
 284         sbi = EXT4_SB(sb);
 285
 286         ino = inode->i_ino;
 287         ext4_debug("freeing inode %lu\n", ino);
 288         trace_ext4_free_inode(inode);
 289
 290         /*
 291          * Note: we must free any quota before locking the superblock,
 292          * as writing the quota to disk may need the lock as well.
 293          */
 294         dquot_initialize(inode);
 295         ext4_xattr_delete_inode(handle, inode);
 296         dquot_free_inode(inode);
 297         dquot_drop(inode);
 298
 299         is_directory = S_ISDIR(inode->i_mode);
 300
 301         /* Do this BEFORE marking the inode not in use or returning an error */
 302         ext4_clear_inode(inode);
 303
 304         es = EXT4_SB(sb)->s_es;
 305         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 306                 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
 307                 goto error_return;
 308         }
 309         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 310         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 311         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 312         /* Don't bother if the inode bitmap is corrupt. */
 313         grp = ext4_get_group_info(sb, block_group);
 314         if (IS_ERR(bitmap_bh)) {
 315                 fatal = PTR_ERR(bitmap_bh);
 316                 bitmap_bh = NULL;
 317                 goto error_return;
 318         }
 319         if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
 320                 fatal = -EFSCORRUPTED;
 321                 goto error_return;
 322         }
 323
 324         BUFFER_TRACE(bitmap_bh, "get_write_access");
 325         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 326         if (fatal)
 327                 goto error_return;
 328
 329         fatal = -ESRCH;
 330         gdp = ext4_get_group_desc(sb, block_group, &bh2);
 331         if (gdp) {
 332                 BUFFER_TRACE(bh2, "get_write_access");
 333                 fatal = ext4_journal_get_write_access(handle, bh2);
 334         }
 335         ext4_lock_group(sb, block_group);
 336         cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
 337         if (fatal || !cleared) {
 338                 ext4_unlock_group(sb, block_group);
 339                 goto out;
 340         }
 341
 342         count = ext4_free_inodes_count(sb, gdp) + 1;
 343         ext4_free_inodes_set(sb, gdp, count);
 344         if (is_directory) {
 345                 count = ext4_used_dirs_count(sb, gdp) - 1;
 346                 ext4_used_dirs_set(sb, gdp, count);
 347                 percpu_counter_dec(&sbi->s_dirs_counter);
 348         }
 349         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
 350                                    EXT4_INODES_PER_GROUP(sb) / 8);
 351         ext4_group_desc_csum_set(sb, block_group, gdp);
 352         ext4_unlock_group(sb, block_group);
 353
 354         percpu_counter_inc(&sbi->s_freeinodes_counter);
 355         if (sbi->s_log_groups_per_flex) {
 356                 ext4_group_t f = ext4_flex_group(sbi, block_group);
 357
 358                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 359                 if (is_directory)
 360                         atomic_dec(&sbi->s_flex_groups[f].used_dirs);
 361         }
 362         BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 363         fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
 364 out:
 365         if (cleared) {
 366                 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 367                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 368                 if (!fatal)
 369                         fatal = err;
 370         } else {
 371                 ext4_error(sb, "bit already cleared for inode %lu", ino);
 372                 if (gdp && !EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 373                         int count;
 374                         count = ext4_free_inodes_count(sb, gdp);
 375                         percpu_counter_sub(&sbi->s_freeinodes_counter,
 376                                            count);
 377                 }
 378                 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
 379         }
 380
 381 error_return:
 382         brelse(bitmap_bh);
 383         ext4_std_error(sb, fatal);
 384 }
 385
 386 struct orlov_stats {
 387         __u64 free_clusters;
 388         __u32 free_inodes;
 389         __u32 used_dirs;
 390 };
 391
 392 /*
 393  * Helper function for Orlov's allocator; returns critical information
 394  * for a particular block group or flex_bg.  If flex_size is 1, then g
 395  * is a block group number; otherwise it is flex_bg number.
 396  */
 397 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 398                             int flex_size, struct orlov_stats *stats)
 399 {
 400         struct ext4_group_desc *desc;
 401         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
 402
 403         if (flex_size > 1) {
 404                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
 405                 stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
 406                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
 407                 return;
 408         }
 409
 410         desc = ext4_get_group_desc(sb, g, NULL);
 411         if (desc) {
 412                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
 413                 stats->free_clusters = ext4_free_group_clusters(sb, desc);
 414                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
 415         } else {
 416                 stats->free_inodes = 0;
 417                 stats->free_clusters = 0;
 418                 stats->used_dirs = 0;
 419         }
 420 }
 421
 422 /*
 423  * Orlov's allocator for directories.
 424  *
 425  * We always try to spread first-level directories.
 426  *
 427  * If there are blockgroups with both free inodes and free blocks counts
 428  * not worse than average we return one with smallest directory count.
 429  * Otherwise we simply return a random group.
 430  *
 431  * For the rest rules look so:
 432  *
 433  * It's OK to put directory into a group unless
 434  * it has too many directories already (max_dirs) or
 435  * it has too few free inodes left (min_inodes) or
 436  * it has too few free blocks left (min_blocks) or
 437  * Parent's group is preferred, if it doesn't satisfy these
 438  * conditions we search cyclically through the rest. If none
 439  * of the groups look good we just look for a group with more
 440  * free inodes than average (starting at parent's group).
 441  */
 442
 443 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 444                             ext4_group_t *group, umode_t mode,
 445                             const struct qstr *qstr)
 446 {
 447         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 448         struct ext4_sb_info *sbi = EXT4_SB(sb);
 449         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 450         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 451         unsigned int freei, avefreei, grp_free;
 452         ext4_fsblk_t freeb, avefreec;
 453         unsigned int ndirs;
 454         int max_dirs, min_inodes;
 455         ext4_grpblk_t min_clusters;
 456         ext4_group_t i, grp, g, ngroups;
 457         struct ext4_group_desc *desc;
 458         struct orlov_stats stats;
 459         int flex_size = ext4_flex_bg_size(sbi);
 460         struct dx_hash_info hinfo;
 461
 462         ngroups = real_ngroups;
 463         if (flex_size > 1) {
 464                 ngroups = (real_ngroups + flex_size - 1) >>
 465                         sbi->s_log_groups_per_flex;
 466                 parent_group >>= sbi->s_log_groups_per_flex;
 467         }
 468
 469         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 470         avefreei = freei / ngroups;
 471         freeb = EXT4_C2B(sbi,
 472                 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
 473         avefreec = freeb;
 474         do_div(avefreec, ngroups);
 475         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 476
 477         if (S_ISDIR(mode) &&
 478             ((parent == d_inode(sb->s_root)) ||
 479              (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
 480                 int best_ndir = inodes_per_group;
 481                 int ret = -1;
 482
 483                 if (qstr) {
 484                         hinfo.hash_version = DX_HASH_HALF_MD4;
 485                         hinfo.seed = sbi->s_hash_seed;
 486                         ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
 487                         grp = hinfo.hash;
 488                 } else
 489                         grp = prandom_u32();
 490                 parent_group = (unsigned)grp % ngroups;
 491                 for (i = 0; i < ngroups; i++) {
 492                         g = (parent_group + i) % ngroups;
 493                         get_orlov_stats(sb, g, flex_size, &stats);
 494                         if (!stats.free_inodes)
 495                                 continue;
 496                         if (stats.used_dirs >= best_ndir)
 497                                 continue;
 498                         if (stats.free_inodes < avefreei)
 499                                 continue;
 500                         if (stats.free_clusters < avefreec)
 501                                 continue;
 502                         grp = g;
 503                         ret = 0;
 504                         best_ndir = stats.used_dirs;
 505                 }
 506                 if (ret)
 507                         goto fallback;
 508         found_flex_bg:
 509                 if (flex_size == 1) {
 510                         *group = grp;
 511                         return 0;
 512                 }
 513
 514                 /*
 515                  * We pack inodes at the beginning of the flexgroup's
 516                  * inode tables.  Block allocation decisions will do
 517                  * something similar, although regular files will
 518                  * start at 2nd block group of the flexgroup.  See
 519                  * ext4_ext_find_goal() and ext4_find_near().
 520                  */
 521                 grp *= flex_size;
 522                 for (i = 0; i < flex_size; i++) {
 523                         if (grp+i >= real_ngroups)
 524                                 break;
 525                         desc = ext4_get_group_desc(sb, grp+i, NULL);
 526                         if (desc && ext4_free_inodes_count(sb, desc)) {
 527                                 *group = grp+i;
 528                                 return 0;
 529                         }
 530                 }
 531                 goto fallback;
 532         }
 533
 534         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 535         min_inodes = avefreei - inodes_per_group*flex_size / 4;
 536         if (min_inodes < 1)
 537                 min_inodes = 1;
 538         min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
 539
 540         /*
 541          * Start looking in the flex group where we last allocated an
 542          * inode for this parent directory
 543          */
 544         if (EXT4_I(parent)->i_last_alloc_group != ~0) {
 545                 parent_group = EXT4_I(parent)->i_last_alloc_group;
 546                 if (flex_size > 1)
 547                         parent_group >>= sbi->s_log_groups_per_flex;
 548         }
 549
 550         for (i = 0; i < ngroups; i++) {
 551                 grp = (parent_group + i) % ngroups;
 552                 get_orlov_stats(sb, grp, flex_size, &stats);
 553                 if (stats.used_dirs >= max_dirs)
 554                         continue;
 555                 if (stats.free_inodes < min_inodes)
 556                         continue;
 557                 if (stats.free_clusters < min_clusters)
 558                         continue;
 559                 goto found_flex_bg;
 560         }
 561
 562 fallback:
 563         ngroups = real_ngroups;
 564         avefreei = freei / ngroups;
 565 fallback_retry:
 566         parent_group = EXT4_I(parent)->i_block_group;
 567         for (i = 0; i < ngroups; i++) {
 568                 grp = (parent_group + i) % ngroups;
 569                 desc = ext4_get_group_desc(sb, grp, NULL);
 570                 if (desc) {
 571                         grp_free = ext4_free_inodes_count(sb, desc);
 572                         if (grp_free && grp_free >= avefreei) {
 573                                 *group = grp;
 574                                 return 0;
 575                         }
 576                 }
 577         }
 578
 579         if (avefreei) {
 580                 /*
 581                  * The free-inodes counter is approximate, and for really small
 582                  * filesystems the above test can fail to find any blockgroups
 583                  */
 584                 avefreei = 0;
 585                 goto fallback_retry;
 586         }
 587
 588         return -1;
 589 }
 590
 591 static int find_group_other(struct super_block *sb, struct inode *parent,
 592                             ext4_group_t *group, umode_t mode)
 593 {
 594         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 595         ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
 596         struct ext4_group_desc *desc;
 597         int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
 598
 599         /*
 600          * Try to place the inode is the same flex group as its
 601          * parent.  If we can't find space, use the Orlov algorithm to
 602          * find another flex group, and store that information in the
 603          * parent directory's inode information so that use that flex
 604          * group for future allocations.
 605          */
 606         if (flex_size > 1) {
 607                 int retry = 0;
 608
 609         try_again:
 610                 parent_group &= ~(flex_size-1);
 611                 last = parent_group + flex_size;
 612                 if (last > ngroups)
 613                         last = ngroups;
 614                 for  (i = parent_group; i < last; i++) {
 615                         desc = ext4_get_group_desc(sb, i, NULL);
 616                         if (desc && ext4_free_inodes_count(sb, desc)) {
 617                                 *group = i;
 618                                 return 0;
 619                         }
 620                 }
 621                 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
 622                         retry = 1;
 623                         parent_group = EXT4_I(parent)->i_last_alloc_group;
 624                         goto try_again;
 625                 }
 626                 /*
 627                  * If this didn't work, use the Orlov search algorithm
 628                  * to find a new flex group; we pass in the mode to
 629                  * avoid the topdir algorithms.
 630                  */
 631                 *group = parent_group + flex_size;
 632                 if (*group > ngroups)
 633                         *group = 0;
 634                 return find_group_orlov(sb, parent, group, mode, NULL);
 635         }
 636
 637         /*
 638          * Try to place the inode in its parent directory
 639          */
 640         *group = parent_group;
 641         desc = ext4_get_group_desc(sb, *group, NULL);
 642         if (desc && ext4_free_inodes_count(sb, desc) &&
 643             ext4_free_group_clusters(sb, desc))
 644                 return 0;
 645
 646         /*
 647          * We're going to place this inode in a different blockgroup from its
 648          * parent.  We want to cause files in a common directory to all land in
 649          * the same blockgroup.  But we want files which are in a different
 650          * directory which shares a blockgroup with our parent to land in a
 651          * different blockgroup.
 652          *
 653          * So add our directory's i_ino into the starting point for the hash.
 654          */
 655         *group = (*group + parent->i_ino) % ngroups;
 656
 657         /*
 658          * Use a quadratic hash to find a group with a free inode and some free
 659          * blocks.
 660          */
 661         for (i = 1; i < ngroups; i <<= 1) {
 662                 *group += i;
 663                 if (*group >= ngroups)
 664                         *group -= ngroups;
 665                 desc = ext4_get_group_desc(sb, *group, NULL);
 666                 if (desc && ext4_free_inodes_count(sb, desc) &&
 667                     ext4_free_group_clusters(sb, desc))
 668                         return 0;
 669         }
 670
 671         /*
 672          * That failed: try linear search for a free inode, even if that group
 673          * has no free blocks.
 674          */
 675         *group = parent_group;
 676         for (i = 0; i < ngroups; i++) {
 677                 if (++*group >= ngroups)
 678                         *group = 0;
 679                 desc = ext4_get_group_desc(sb, *group, NULL);
 680                 if (desc && ext4_free_inodes_count(sb, desc))
 681                         return 0;
 682         }
 683
 684         return -1;
 685 }
 686
 687 /*
 688  * In no journal mode, if an inode has recently been deleted, we want
 689  * to avoid reusing it until we're reasonably sure the inode table
 690  * block has been written back to disk.  (Yes, these values are
 691  * somewhat arbitrary...)
 692  */
 693 #define RECENTCY_MIN    5
 694 #define RECENTCY_DIRTY  30
 695
 696 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
 697 {
 698         struct ext4_group_desc  *gdp;
 699         struct ext4_inode       *raw_inode;
 700         struct buffer_head      *bh;
 701         unsigned long           dtime, now;
 702         int     inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
 703         int     offset, ret = 0, recentcy = RECENTCY_MIN;
 704
 705         gdp = ext4_get_group_desc(sb, group, NULL);
 706         if (unlikely(!gdp))
 707                 return 0;
 708
 709         bh = sb_getblk(sb, ext4_inode_table(sb, gdp) +
 710                        (ino / inodes_per_block));
 711         if (unlikely(!bh) || !buffer_uptodate(bh))
 712                 /*
 713                  * If the block is not in the buffer cache, then it
 714                  * must have been written out.
 715                  */
 716                 goto out;
 717
 718         offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
 719         raw_inode = (struct ext4_inode *) (bh->b_data + offset);
 720         dtime = le32_to_cpu(raw_inode->i_dtime);
 721         now = get_seconds();
 722         if (buffer_dirty(bh))
 723                 recentcy += RECENTCY_DIRTY;
 724
 725         if (dtime && (dtime < now) && (now < dtime + recentcy))
 726                 ret = 1;
 727 out:
 728         brelse(bh);
 729         return ret;
 730 }
 731
 732 /*
 733  * There are two policies for allocating an inode.  If the new inode is
 734  * a directory, then a forward search is made for a block group with both
 735  * free space and a low directory-to-inode ratio; if that fails, then of
 736  * the groups with above-average free space, that group with the fewest
 737  * directories already is chosen.
 738  *
 739  * For other inodes, search forward from the parent directory's block
 740  * group to find a free inode.
 741  */
 742 struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 743                                umode_t mode, const struct qstr *qstr,
 744                                __u32 goal, uid_t *owner, int handle_type,
 745                                unsigned int line_no, int nblocks)
 746 {
 747         struct super_block *sb;
 748         struct buffer_head *inode_bitmap_bh = NULL;
 749         struct buffer_head *group_desc_bh;
 750         ext4_group_t ngroups, group = 0;
 751         unsigned long ino = 0;
 752         struct inode *inode;
 753         struct ext4_group_desc *gdp = NULL;
 754         struct ext4_inode_info *ei;
 755         struct ext4_sb_info *sbi;
 756         int ret2, err;
 757         struct inode *ret;
 758         ext4_group_t i;
 759         ext4_group_t flex_group;
 760         struct ext4_group_info *grp;
 761         int encrypt = 0;
 762
 763         /* Cannot create files in a deleted directory */
 764         if (!dir || !dir->i_nlink)
 765                 return ERR_PTR(-EPERM);
 766
 767         if ((ext4_encrypted_inode(dir) ||
 768              DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb))) &&
 769             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
 770                 err = fscrypt_get_encryption_info(dir);
 771                 if (err)
 772                         return ERR_PTR(err);
 773                 if (!fscrypt_has_encryption_key(dir))
 774                         return ERR_PTR(-EPERM);
 775                 if (!handle)
 776                         nblocks += EXT4_DATA_TRANS_BLOCKS(dir->i_sb);
 777                 encrypt = 1;
 778         }
 779
 780         sb = dir->i_sb;
 781         ngroups = ext4_get_groups_count(sb);
 782         trace_ext4_request_inode(dir, mode);
 783         inode = new_inode(sb);
 784         if (!inode)
 785                 return ERR_PTR(-ENOMEM);
 786         ei = EXT4_I(inode);
 787         sbi = EXT4_SB(sb);
 788
 789         /*
 790          * Initialize owners and quota early so that we don't have to account
 791          * for quota initialization worst case in standard inode creating
 792          * transaction
 793          */
 794         if (owner) {
 795                 inode->i_mode = mode;
 796                 i_uid_write(inode, owner[0]);
 797                 i_gid_write(inode, owner[1]);
 798         } else if (test_opt(sb, GRPID)) {
 799                 inode->i_mode = mode;
 800                 inode->i_uid = current_fsuid();
 801                 inode->i_gid = dir->i_gid;
 802         } else
 803                 inode_init_owner(inode, dir, mode);
 804
 805         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_PROJECT) &&
 806             ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
 807                 ei->i_projid = EXT4_I(dir)->i_projid;
 808         else
 809                 ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
 810
 811         err = dquot_initialize(inode);
 812         if (err)
 813                 goto out;
 814
 815         if (!goal)
 816                 goal = sbi->s_inode_goal;
 817
 818         if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
 819                 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
 820                 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
 821                 ret2 = 0;
 822                 goto got_group;
 823         }
 824
 825         if (S_ISDIR(mode))
 826                 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
 827         else
 828                 ret2 = find_group_other(sb, dir, &group, mode);
 829
 830 got_group:
 831         EXT4_I(dir)->i_last_alloc_group = group;
 832         err = -ENOSPC;
 833         if (ret2 == -1)
 834                 goto out;
 835
 836         /*
 837          * Normally we will only go through one pass of this loop,
 838          * unless we get unlucky and it turns out the group we selected
 839          * had its last inode grabbed by someone else.
 840          */
 841         for (i = 0; i < ngroups; i++, ino = 0) {
 842                 err = -EIO;
 843
 844                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 845                 if (!gdp)
 846                         goto out;
 847
 848                 /*
 849                  * Check free inodes count before loading bitmap.
 850                  */
 851                 if (ext4_free_inodes_count(sb, gdp) == 0) {
 852                         if (++group == ngroups)
 853                                 group = 0;
 854                         continue;
 855                 }
 856
 857                 grp = ext4_get_group_info(sb, group);
 858                 /* Skip groups with already-known suspicious inode tables */
 859                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
 860                         if (++group == ngroups)
 861                                 group = 0;
 862                         continue;
 863                 }
 864
 865                 brelse(inode_bitmap_bh);
 866                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 867                 /* Skip groups with suspicious inode tables */
 868                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
 869                     IS_ERR(inode_bitmap_bh)) {
 870                         inode_bitmap_bh = NULL;
 871                         if (++group == ngroups)
 872                                 group = 0;
 873                         continue;
 874                 }
 875
 876 repeat_in_this_group:
 877                 ino = ext4_find_next_zero_bit((unsigned long *)
 878                                               inode_bitmap_bh->b_data,
 879                                               EXT4_INODES_PER_GROUP(sb), ino);
 880                 if (ino >= EXT4_INODES_PER_GROUP(sb))
 881                         goto next_group;
 882                 if (group == 0 && (ino+1) < EXT4_FIRST_INO(sb)) {
 883                         ext4_error(sb, "reserved inode found cleared - "
 884                                    "inode=%lu", ino + 1);
 885                         continue;
 886                 }
 887                 if ((EXT4_SB(sb)->s_journal == NULL) &&
 888                     recently_deleted(sb, group, ino)) {
 889                         ino++;
 890                         goto next_inode;
 891                 }
 892                 if (!handle) {
 893                         BUG_ON(nblocks <= 0);
 894                         handle = __ext4_journal_start_sb(dir->i_sb, line_no,
 895                                                          handle_type, nblocks,
 896                                                          0);
 897                         if (IS_ERR(handle)) {
 898                                 err = PTR_ERR(handle);
 899                                 ext4_std_error(sb, err);
 900                                 goto out;
 901                         }
 902                 }
 903                 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 904                 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
 905                 if (err) {
 906                         ext4_std_error(sb, err);
 907                         goto out;
 908                 }
 909                 ext4_lock_group(sb, group);
 910                 ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
 911                 ext4_unlock_group(sb, group);
 912                 ino++;          /* the inode bitmap is zero-based */
 913                 if (!ret2)
 914                         goto got; /* we grabbed the inode! */
 915 next_inode:
 916                 if (ino < EXT4_INODES_PER_GROUP(sb))
 917                         goto repeat_in_this_group;
 918 next_group:
 919                 if (++group == ngroups)
 920                         group = 0;
 921         }
 922         err = -ENOSPC;
 923         goto out;
 924
 925 got:
 926         BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
 927         err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
 928         if (err) {
 929                 ext4_std_error(sb, err);
 930                 goto out;
 931         }
 932
 933         BUFFER_TRACE(group_desc_bh, "get_write_access");
 934         err = ext4_journal_get_write_access(handle, group_desc_bh);
 935         if (err) {
 936                 ext4_std_error(sb, err);
 937                 goto out;
 938         }
 939
 940         /* We may have to initialize the block bitmap if it isn't already */
 941         if (ext4_has_group_desc_csum(sb) &&
 942             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 943                 struct buffer_head *block_bitmap_bh;
 944
 945                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 946                 if (IS_ERR(block_bitmap_bh)) {
 947                         err = PTR_ERR(block_bitmap_bh);
 948                         goto out;
 949                 }
 950                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 951                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 952                 if (err) {
 953                         brelse(block_bitmap_bh);
 954                         ext4_std_error(sb, err);
 955                         goto out;
 956                 }
 957
 958                 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
 959                 err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
 960
 961                 /* recheck and clear flag under lock if we still need to */
 962                 ext4_lock_group(sb, group);
 963                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 964                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 965                         ext4_free_group_clusters_set(sb, gdp,
 966                                 ext4_free_clusters_after_init(sb, group, gdp));
 967                         ext4_block_bitmap_csum_set(sb, group, gdp,
 968                                                    block_bitmap_bh);
 969                         ext4_group_desc_csum_set(sb, group, gdp);
 970                 }
 971                 ext4_unlock_group(sb, group);
 972                 brelse(block_bitmap_bh);
 973
 974                 if (err) {
 975                         ext4_std_error(sb, err);
 976                         goto out;
 977                 }
 978         }
 979
 980         /* Update the relevant bg descriptor fields */
 981         if (ext4_has_group_desc_csum(sb)) {
 982                 int free;
 983                 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
 984
 985                 down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
 986                 ext4_lock_group(sb, group); /* while we modify the bg desc */
 987                 free = EXT4_INODES_PER_GROUP(sb) -
 988                         ext4_itable_unused_count(sb, gdp);
 989                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 990                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 991                         free = 0;
 992                 }
 993                 /*
 994                  * Check the relative inode number against the last used
 995                  * relative inode number in this group. if it is greater
 996                  * we need to update the bg_itable_unused count
 997                  */
 998                 if (ino > free)
 999                         ext4_itable_unused_set(sb, gdp,
1000                                         (EXT4_INODES_PER_GROUP(sb) - ino));
1001                 up_read(&grp->alloc_sem);
1002         } else {
1003                 ext4_lock_group(sb, group);
1004         }
1005
1006         ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1007         if (S_ISDIR(mode)) {
1008                 ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1009                 if (sbi->s_log_groups_per_flex) {
1010                         ext4_group_t f = ext4_flex_group(sbi, group);
1011
1012                         atomic_inc(&sbi->s_flex_groups[f].used_dirs);
1013                 }
1014         }
1015         if (ext4_has_group_desc_csum(sb)) {
1016                 ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1017                                            EXT4_INODES_PER_GROUP(sb) / 8);
1018                 ext4_group_desc_csum_set(sb, group, gdp);
1019         }
1020         ext4_unlock_group(sb, group);
1021
1022         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1023         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1024         if (err) {
1025                 ext4_std_error(sb, err);
1026                 goto out;
1027         }
1028
1029         percpu_counter_dec(&sbi->s_freeinodes_counter);
1030         if (S_ISDIR(mode))
1031                 percpu_counter_inc(&sbi->s_dirs_counter);
1032
1033         if (sbi->s_log_groups_per_flex) {
1034                 flex_group = ext4_flex_group(sbi, group);
1035                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
1036         }
1037
1038         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1039         /* This is the optimal IO size (for stat), not the fs block size */
1040         inode->i_blocks = 0;
1041         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
1042                                                        ext4_current_time(inode);
1043
1044         memset(ei->i_data, 0, sizeof(ei->i_data));
1045         ei->i_dir_start_lookup = 0;
1046         ei->i_disksize = 0;
1047
1048         /* Don't inherit extent flag from directory, amongst others. */
1049         ei->i_flags =
1050                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1051         ei->i_file_acl = 0;
1052         ei->i_dtime = 0;
1053         ei->i_block_group = group;
1054         ei->i_last_alloc_group = ~0;
1055
1056         ext4_set_inode_flags(inode);
1057         if (IS_DIRSYNC(inode))
1058                 ext4_handle_sync(handle);
1059         if (insert_inode_locked(inode) < 0) {
1060                 /*
1061                  * Likely a bitmap corruption causing inode to be allocated
1062                  * twice.
1063                  */
1064                 err = -EIO;
1065                 ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1066                            inode->i_ino);
1067                 goto out;
1068         }
1069         spin_lock(&sbi->s_next_gen_lock);
1070         inode->i_generation = sbi->s_next_generation++;
1071         spin_unlock(&sbi->s_next_gen_lock);
1072
1073         /* Precompute checksum seed for inode metadata */
1074         if (ext4_has_metadata_csum(sb)) {
1075                 __u32 csum;
1076                 __le32 inum = cpu_to_le32(inode->i_ino);
1077                 __le32 gen = cpu_to_le32(inode->i_generation);
1078                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1079                                    sizeof(inum));
1080                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1081                                               sizeof(gen));
1082         }
1083
1084         ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1085         ext4_set_inode_state(inode, EXT4_STATE_NEW);
1086
1087         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
1088         ei->i_inline_off = 0;
1089         if (ext4_has_feature_inline_data(sb))
1090                 ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1091         ret = inode;
1092         err = dquot_alloc_inode(inode);
1093         if (err)
1094                 goto fail_drop;
1095
1096         err = ext4_init_acl(handle, inode, dir);
1097         if (err)
1098                 goto fail_free_drop;
1099
1100         err = ext4_init_security(handle, inode, dir, qstr);
1101         if (err)
1102                 goto fail_free_drop;
1103
1104         if (ext4_has_feature_extents(sb)) {
1105                 /* set extent flag only for directory, file and normal symlink*/
1106                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1107                         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1108                         ext4_ext_tree_init(handle, inode);
1109                 }
1110         }
1111
1112         if (ext4_handle_valid(handle)) {
1113                 ei->i_sync_tid = handle->h_transaction->t_tid;
1114                 ei->i_datasync_tid = handle->h_transaction->t_tid;
1115         }
1116
1117         if (encrypt) {
1118                 /* give pointer to avoid set_context with journal ops. */
1119                 err = fscrypt_inherit_context(dir, inode, &encrypt, true);
1120                 if (err)
1121                         goto fail_free_drop;
1122         }
1123
1124         err = ext4_mark_inode_dirty(handle, inode);
1125         if (err) {
1126                 ext4_std_error(sb, err);
1127                 goto fail_free_drop;
1128         }
1129
1130         ext4_debug("allocating inode %lu\n", inode->i_ino);
1131         trace_ext4_allocate_inode(inode, dir, mode);
1132         brelse(inode_bitmap_bh);
1133         return ret;
1134
1135 fail_free_drop:
1136         dquot_free_inode(inode);
1137 fail_drop:
1138         clear_nlink(inode);
1139         unlock_new_inode(inode);
1140 out:
1141         dquot_drop(inode);
1142         inode->i_flags |= S_NOQUOTA;
1143         iput(inode);
1144         brelse(inode_bitmap_bh);
1145         return ERR_PTR(err);
1146 }
1147
1148 /* Verify that we are loading a valid orphan from disk */
1149 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1150 {
1151         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1152         ext4_group_t block_group;
1153         int bit;
1154         struct buffer_head *bitmap_bh = NULL;
1155         struct inode *inode = NULL;
1156         int err = -EFSCORRUPTED;
1157
1158         if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
1159                 goto bad_orphan;
1160
1161         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1162         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1163         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1164         if (IS_ERR(bitmap_bh)) {
1165                 ext4_error(sb, "inode bitmap error %ld for orphan %lu",
1166                            ino, PTR_ERR(bitmap_bh));
1167                 return (struct inode *) bitmap_bh;
1168         }
1169
1170         /* Having the inode bit set should be a 100% indicator that this
1171          * is a valid orphan (no e2fsck run on fs).  Orphans also include
1172          * inodes that were being truncated, so we can't check i_nlink==0.
1173          */
1174         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1175                 goto bad_orphan;
1176
1177         inode = ext4_iget(sb, ino);
1178         if (IS_ERR(inode)) {
1179                 err = PTR_ERR(inode);
1180                 ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
1181                            ino, err);
1182                 return inode;
1183         }
1184
1185         /*
1186          * If the orphans has i_nlinks > 0 then it should be able to
1187          * be truncated, otherwise it won't be removed from the orphan
1188          * list during processing and an infinite loop will result.
1189          * Similarly, it must not be a bad inode.
1190          */
1191         if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
1192             is_bad_inode(inode))
1193                 goto bad_orphan;
1194
1195         if (NEXT_ORPHAN(inode) > max_ino)
1196                 goto bad_orphan;
1197         brelse(bitmap_bh);
1198         return inode;
1199
1200 bad_orphan:
1201         ext4_error(sb, "bad orphan inode %lu", ino);
1202         if (bitmap_bh)
1203                 printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1204                        bit, (unsigned long long)bitmap_bh->b_blocknr,
1205                        ext4_test_bit(bit, bitmap_bh->b_data));
1206         if (inode) {
1207                 printk(KERN_ERR "is_bad_inode(inode)=%d\n",
1208                        is_bad_inode(inode));
1209                 printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
1210                        NEXT_ORPHAN(inode));
1211                 printk(KERN_ERR "max_ino=%lu\n", max_ino);
1212                 printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
1213                 /* Avoid freeing blocks if we got a bad deleted inode */
1214                 if (inode->i_nlink == 0)
1215                         inode->i_blocks = 0;
1216                 iput(inode);
1217         }
1218         brelse(bitmap_bh);
1219         return ERR_PTR(err);
1220 }
1221
1222 unsigned long ext4_count_free_inodes(struct super_block *sb)
1223 {
1224         unsigned long desc_count;
1225         struct ext4_group_desc *gdp;
1226         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1227 #ifdef EXT4FS_DEBUG
1228         struct ext4_super_block *es;
1229         unsigned long bitmap_count, x;
1230         struct buffer_head *bitmap_bh = NULL;
1231
1232         es = EXT4_SB(sb)->s_es;
1233         desc_count = 0;
1234         bitmap_count = 0;
1235         gdp = NULL;
1236         for (i = 0; i < ngroups; i++) {
1237                 gdp = ext4_get_group_desc(sb, i, NULL);
1238                 if (!gdp)
1239                         continue;
1240                 desc_count += ext4_free_inodes_count(sb, gdp);
1241                 brelse(bitmap_bh);
1242                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1243                 if (IS_ERR(bitmap_bh)) {
1244                         bitmap_bh = NULL;
1245                         continue;
1246                 }
1247
1248                 x = ext4_count_free(bitmap_bh->b_data,
1249                                     EXT4_INODES_PER_GROUP(sb) / 8);
1250                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1251                         (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1252                 bitmap_count += x;
1253         }
1254         brelse(bitmap_bh);
1255         printk(KERN_DEBUG "ext4_count_free_inodes: "
1256                "stored = %u, computed = %lu, %lu\n",
1257                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1258         return desc_count;
1259 #else
1260         desc_count = 0;
1261         for (i = 0; i < ngroups; i++) {
1262                 gdp = ext4_get_group_desc(sb, i, NULL);
1263                 if (!gdp)
1264                         continue;
1265                 desc_count += ext4_free_inodes_count(sb, gdp);
1266                 cond_resched();
1267         }
1268         return desc_count;
1269 #endif
1270 }
1271
1272 /* Called at mount-time, super-block is locked */
1273 unsigned long ext4_count_dirs(struct super_block * sb)
1274 {
1275         unsigned long count = 0;
1276         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1277
1278         for (i = 0; i < ngroups; i++) {
1279                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1280                 if (!gdp)
1281                         continue;
1282                 count += ext4_used_dirs_count(sb, gdp);
1283         }
1284         return count;
1285 }
1286
1287 /*
1288  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1289  * inode table. Must be called without any spinlock held. The only place
1290  * where it is called from on active part of filesystem is ext4lazyinit
1291  * thread, so we do not need any special locks, however we have to prevent
1292  * inode allocation from the current group, so we take alloc_sem lock, to
1293  * block ext4_new_inode() until we are finished.
1294  */
1295 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1296                                  int barrier)
1297 {
1298         struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1299         struct ext4_sb_info *sbi = EXT4_SB(sb);
1300         struct ext4_group_desc *gdp = NULL;
1301         struct buffer_head *group_desc_bh;
1302         handle_t *handle;
1303         ext4_fsblk_t blk;
1304         int num, ret = 0, used_blks = 0;
1305
1306         /* This should not happen, but just to be sure check this */
1307         if (sb->s_flags & MS_RDONLY) {
1308                 ret = 1;
1309                 goto out;
1310         }
1311
1312         gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1313         if (!gdp)
1314                 goto out;
1315
1316         /*
1317          * We do not need to lock this, because we are the only one
1318          * handling this flag.
1319          */
1320         if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1321                 goto out;
1322
1323         handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1324         if (IS_ERR(handle)) {
1325                 ret = PTR_ERR(handle);
1326                 goto out;
1327         }
1328
1329         down_write(&grp->alloc_sem);
1330         /*
1331          * If inode bitmap was already initialized there may be some
1332          * used inodes so we need to skip blocks with used inodes in
1333          * inode table.
1334          */
1335         if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1336                 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1337                             ext4_itable_unused_count(sb, gdp)),
1338                             sbi->s_inodes_per_block);
1339
1340         if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1341                 ext4_error(sb, "Something is wrong with group %u: "
1342                            "used itable blocks: %d; "
1343                            "itable unused count: %u",
1344                            group, used_blks,
1345                            ext4_itable_unused_count(sb, gdp));
1346                 ret = 1;
1347                 goto err_out;
1348         }
1349
1350         blk = ext4_inode_table(sb, gdp) + used_blks;
1351         num = sbi->s_itb_per_group - used_blks;
1352
1353         BUFFER_TRACE(group_desc_bh, "get_write_access");
1354         ret = ext4_journal_get_write_access(handle,
1355                                             group_desc_bh);
1356         if (ret)
1357                 goto err_out;
1358
1359         /*
1360          * Skip zeroout if the inode table is full. But we set the ZEROED
1361          * flag anyway, because obviously, when it is full it does not need
1362          * further zeroing.
1363          */
1364         if (unlikely(num == 0))
1365                 goto skip_zeroout;
1366
1367         ext4_debug("going to zero out inode table in group %d\n",
1368                    group);
1369         ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1370         if (ret < 0)
1371                 goto err_out;
1372         if (barrier)
1373                 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1374
1375 skip_zeroout:
1376         ext4_lock_group(sb, group);
1377         gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1378         ext4_group_desc_csum_set(sb, group, gdp);
1379         ext4_unlock_group(sb, group);
1380
1381         BUFFER_TRACE(group_desc_bh,
1382                      "call ext4_handle_dirty_metadata");
1383         ret = ext4_handle_dirty_metadata(handle, NULL,
1384                                          group_desc_bh);
1385
1386 err_out:
1387         up_write(&grp->alloc_sem);
1388         ext4_journal_stop(handle);
1389 out:
1390         return ret;
1391 }