fs/ext4/ialloc.c

   1 /*
   2  *  linux/fs/ext4/ialloc.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  BSD ufs-inspired inode and directory allocation by
  10  *  Stephen Tweedie (sct@redhat.com), 1993
  11  *  Big-endian to little-endian byte-swapping/bitmaps by
  12  *        David S. Miller (davem@caip.rutgers.edu), 1995
  13  */
  14
  15 #include <linux/time.h>
  16 #include <linux/fs.h>
  17 #include <linux/jbd2.h>
  18 #include <linux/stat.h>
  19 #include <linux/string.h>
  20 #include <linux/quotaops.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/random.h>
  23 #include <linux/bitops.h>
  24 #include <linux/blkdev.h>
  25 #include <asm/byteorder.h>
  26 #include "ext4.h"
  27 #include "ext4_jbd2.h"
  28 #include "xattr.h"
  29 #include "acl.h"
  30 #include "group.h"
  31
  32 /*
  33  * ialloc.c contains the inodes allocation and deallocation routines
  34  */
  35
  36 /*
  37  * The free inodes are managed by bitmaps.  A file system contains several
  38  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  39  * block for inodes, N blocks for the inode table and data blocks.
  40  *
  41  * The file system contains group descriptors which are located after the
  42  * super block.  Each descriptor contains the number of the bitmap block and
  43  * the free blocks count in the block.
  44  */
  45
  46 /*
  47  * To avoid calling the atomic setbit hundreds or thousands of times, we only
  48  * need to use it within a single byte (to ensure we get endianness right).
  49  * We can use memset for the rest of the bitmap as there are no other users.
  50  */
  51 void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
  52 {
  53         int i;
  54
  55         if (start_bit >= end_bit)
  56                 return;
  57
  58         ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
  59         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
  60                 ext4_set_bit(i, bitmap);
  61         if (i < end_bit)
  62                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
  63 }
  64
  65 /* Initializes an uninitialized inode bitmap */
  66 unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh,
  67                                 ext4_group_t block_group,
  68                                 struct ext4_group_desc *gdp)
  69 {
  70         struct ext4_sb_info *sbi = EXT4_SB(sb);
  71
  72         J_ASSERT_BH(bh, buffer_locked(bh));
  73
  74         /* If checksum is bad mark all blocks and inodes use to prevent
  75          * allocation, essentially implementing a per-group read-only flag. */
  76         if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
  77                 ext4_error(sb, __func__, "Checksum bad for group %lu\n",
  78                            block_group);
  79                 gdp->bg_free_blocks_count = 0;
  80                 gdp->bg_free_inodes_count = 0;
  81                 gdp->bg_itable_unused = 0;
  82                 memset(bh->b_data, 0xff, sb->s_blocksize);
  83                 return 0;
  84         }
  85
  86         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
  87         mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), EXT4_BLOCKS_PER_GROUP(sb),
  88                         bh->b_data);
  89
  90         return EXT4_INODES_PER_GROUP(sb);
  91 }
  92
  93 /*
  94  * Read the inode allocation bitmap for a given block_group, reading
  95  * into the specified slot in the superblock's bitmap cache.
  96  *
  97  * Return buffer_head of bitmap on success or NULL.
  98  */
  99 static struct buffer_head *
 100 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 101 {
 102         struct ext4_group_desc *desc;
 103         struct buffer_head *bh = NULL;
 104         ext4_fsblk_t bitmap_blk;
 105
 106         desc = ext4_get_group_desc(sb, block_group, NULL);
 107         if (!desc)
 108                 return NULL;
 109         bitmap_blk = ext4_inode_bitmap(sb, desc);
 110         bh = sb_getblk(sb, bitmap_blk);
 111         if (unlikely(!bh)) {
 112                 ext4_error(sb, __func__,
 113                             "Cannot read inode bitmap - "
 114                             "block_group = %lu, inode_bitmap = %llu",
 115                             block_group, bitmap_blk);
 116                 return NULL;
 117         }
 118         if (bh_uptodate_or_lock(bh))
 119                 return bh;
 120
 121         spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
 122         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 123                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
 124                 set_buffer_uptodate(bh);
 125                 unlock_buffer(bh);
 126                 spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
 127                 return bh;
 128         }
 129         spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
 130         if (bh_submit_read(bh) < 0) {
 131                 put_bh(bh);
 132                 ext4_error(sb, __func__,
 133                             "Cannot read inode bitmap - "
 134                             "block_group = %lu, inode_bitmap = %llu",
 135                             block_group, bitmap_blk);
 136                 return NULL;
 137         }
 138         return bh;
 139 }
 140
 141 /*
 142  * NOTE! When we get the inode, we're the only people
 143  * that have access to it, and as such there are no
 144  * race conditions we have to worry about. The inode
 145  * is not on the hash-lists, and it cannot be reached
 146  * through the filesystem because the directory entry
 147  * has been deleted earlier.
 148  *
 149  * HOWEVER: we must make sure that we get no aliases,
 150  * which means that we have to call "clear_inode()"
 151  * _before_ we mark the inode not in use in the inode
 152  * bitmaps. Otherwise a newly created file might use
 153  * the same inode number (not actually the same pointer
 154  * though), and then we'd have two inodes sharing the
 155  * same inode number and space on the harddisk.
 156  */
 157 void ext4_free_inode (handle_t *handle, struct inode * inode)
 158 {
 159         struct super_block * sb = inode->i_sb;
 160         int is_directory;
 161         unsigned long ino;
 162         struct buffer_head *bitmap_bh = NULL;
 163         struct buffer_head *bh2;
 164         ext4_group_t block_group;
 165         unsigned long bit;
 166         struct ext4_group_desc * gdp;
 167         struct ext4_super_block * es;
 168         struct ext4_sb_info *sbi;
 169         int fatal = 0, err;
 170         ext4_group_t flex_group;
 171
 172         if (atomic_read(&inode->i_count) > 1) {
 173                 printk ("ext4_free_inode: inode has count=%d\n",
 174                                         atomic_read(&inode->i_count));
 175                 return;
 176         }
 177         if (inode->i_nlink) {
 178                 printk ("ext4_free_inode: inode has nlink=%d\n",
 179                         inode->i_nlink);
 180                 return;
 181         }
 182         if (!sb) {
 183                 printk("ext4_free_inode: inode on nonexistent device\n");
 184                 return;
 185         }
 186         sbi = EXT4_SB(sb);
 187
 188         ino = inode->i_ino;
 189         ext4_debug ("freeing inode %lu\n", ino);
 190
 191         /*
 192          * Note: we must free any quota before locking the superblock,
 193          * as writing the quota to disk may need the lock as well.
 194          */
 195         DQUOT_INIT(inode);
 196         ext4_xattr_delete_inode(handle, inode);
 197         DQUOT_FREE_INODE(inode);
 198         DQUOT_DROP(inode);
 199
 200         is_directory = S_ISDIR(inode->i_mode);
 201
 202         /* Do this BEFORE marking the inode not in use or returning an error */
 203         clear_inode (inode);
 204
 205         es = EXT4_SB(sb)->s_es;
 206         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 207                 ext4_error (sb, "ext4_free_inode",
 208                             "reserved or nonexistent inode %lu", ino);
 209                 goto error_return;
 210         }
 211         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 212         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 213         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 214         if (!bitmap_bh)
 215                 goto error_return;
 216
 217         BUFFER_TRACE(bitmap_bh, "get_write_access");
 218         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 219         if (fatal)
 220                 goto error_return;
 221
 222         /* Ok, now we can actually update the inode bitmaps.. */
 223         if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
 224                                         bit, bitmap_bh->b_data))
 225                 ext4_error (sb, "ext4_free_inode",
 226                               "bit already cleared for inode %lu", ino);
 227         else {
 228                 gdp = ext4_get_group_desc (sb, block_group, &bh2);
 229
 230                 BUFFER_TRACE(bh2, "get_write_access");
 231                 fatal = ext4_journal_get_write_access(handle, bh2);
 232                 if (fatal) goto error_return;
 233
 234                 if (gdp) {
 235                         spin_lock(sb_bgl_lock(sbi, block_group));
 236                         le16_add_cpu(&gdp->bg_free_inodes_count, 1);
 237                         if (is_directory)
 238                                 le16_add_cpu(&gdp->bg_used_dirs_count, -1);
 239                         gdp->bg_checksum = ext4_group_desc_csum(sbi,
 240                                                         block_group, gdp);
 241                         spin_unlock(sb_bgl_lock(sbi, block_group));
 242                         percpu_counter_inc(&sbi->s_freeinodes_counter);
 243                         if (is_directory)
 244                                 percpu_counter_dec(&sbi->s_dirs_counter);
 245
 246                         if (sbi->s_log_groups_per_flex) {
 247                                 flex_group = ext4_flex_group(sbi, block_group);
 248                                 spin_lock(sb_bgl_lock(sbi, flex_group));
 249                                 sbi->s_flex_groups[flex_group].free_inodes++;
 250                                 spin_unlock(sb_bgl_lock(sbi, flex_group));
 251                         }
 252                 }
 253                 BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
 254                 err = ext4_journal_dirty_metadata(handle, bh2);
 255                 if (!fatal) fatal = err;
 256         }
 257         BUFFER_TRACE(bitmap_bh, "call ext4_journal_dirty_metadata");
 258         err = ext4_journal_dirty_metadata(handle, bitmap_bh);
 259         if (!fatal)
 260                 fatal = err;
 261         sb->s_dirt = 1;
 262 error_return:
 263         brelse(bitmap_bh);
 264         ext4_std_error(sb, fatal);
 265 }
 266
 267 /*
 268  * There are two policies for allocating an inode.  If the new inode is
 269  * a directory, then a forward search is made for a block group with both
 270  * free space and a low directory-to-inode ratio; if that fails, then of
 271  * the groups with above-average free space, that group with the fewest
 272  * directories already is chosen.
 273  *
 274  * For other inodes, search forward from the parent directory\'s block
 275  * group to find a free inode.
 276  */
 277 static int find_group_dir(struct super_block *sb, struct inode *parent,
 278                                 ext4_group_t *best_group)
 279 {
 280         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 281         unsigned int freei, avefreei;
 282         struct ext4_group_desc *desc, *best_desc = NULL;
 283         ext4_group_t group;
 284         int ret = -1;
 285
 286         freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
 287         avefreei = freei / ngroups;
 288
 289         for (group = 0; group < ngroups; group++) {
 290                 desc = ext4_get_group_desc (sb, group, NULL);
 291                 if (!desc || !desc->bg_free_inodes_count)
 292                         continue;
 293                 if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
 294                         continue;
 295                 if (!best_desc ||
 296                     (le16_to_cpu(desc->bg_free_blocks_count) >
 297                      le16_to_cpu(best_desc->bg_free_blocks_count))) {
 298                         *best_group = group;
 299                         best_desc = desc;
 300                         ret = 0;
 301                 }
 302         }
 303         return ret;
 304 }
 305
 306 #define free_block_ratio 10
 307
 308 static int find_group_flex(struct super_block *sb, struct inode *parent,
 309                            ext4_group_t *best_group)
 310 {
 311         struct ext4_sb_info *sbi = EXT4_SB(sb);
 312         struct ext4_group_desc *desc;
 313         struct buffer_head *bh;
 314         struct flex_groups *flex_group = sbi->s_flex_groups;
 315         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 316         ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
 317         ext4_group_t ngroups = sbi->s_groups_count;
 318         int flex_size = ext4_flex_bg_size(sbi);
 319         ext4_group_t best_flex = parent_fbg_group;
 320         int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
 321         int flexbg_free_blocks;
 322         int flex_freeb_ratio;
 323         ext4_group_t n_fbg_groups;
 324         ext4_group_t i;
 325
 326         n_fbg_groups = (sbi->s_groups_count + flex_size - 1) >>
 327                 sbi->s_log_groups_per_flex;
 328
 329 find_close_to_parent:
 330         flexbg_free_blocks = flex_group[best_flex].free_blocks;
 331         flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 332         if (flex_group[best_flex].free_inodes &&
 333             flex_freeb_ratio > free_block_ratio)
 334                 goto found_flexbg;
 335
 336         if (best_flex && best_flex == parent_fbg_group) {
 337                 best_flex--;
 338                 goto find_close_to_parent;
 339         }
 340
 341         for (i = 0; i < n_fbg_groups; i++) {
 342                 if (i == parent_fbg_group || i == parent_fbg_group - 1)
 343                         continue;
 344
 345                 flexbg_free_blocks = flex_group[i].free_blocks;
 346                 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 347
 348                 if (flex_freeb_ratio > free_block_ratio &&
 349                     flex_group[i].free_inodes) {
 350                         best_flex = i;
 351                         goto found_flexbg;
 352                 }
 353
 354                 if (flex_group[best_flex].free_inodes == 0 ||
 355                     (flex_group[i].free_blocks >
 356                      flex_group[best_flex].free_blocks &&
 357                      flex_group[i].free_inodes))
 358                         best_flex = i;
 359         }
 360
 361         if (!flex_group[best_flex].free_inodes ||
 362             !flex_group[best_flex].free_blocks)
 363                 return -1;
 364
 365 found_flexbg:
 366         for (i = best_flex * flex_size; i < ngroups &&
 367                      i < (best_flex + 1) * flex_size; i++) {
 368                 desc = ext4_get_group_desc(sb, i, &bh);
 369                 if (le16_to_cpu(desc->bg_free_inodes_count)) {
 370                         *best_group = i;
 371                         goto out;
 372                 }
 373         }
 374
 375         return -1;
 376 out:
 377         return 0;
 378 }
 379
 380 /*
 381  * Orlov's allocator for directories.
 382  *
 383  * We always try to spread first-level directories.
 384  *
 385  * If there are blockgroups with both free inodes and free blocks counts
 386  * not worse than average we return one with smallest directory count.
 387  * Otherwise we simply return a random group.
 388  *
 389  * For the rest rules look so:
 390  *
 391  * It's OK to put directory into a group unless
 392  * it has too many directories already (max_dirs) or
 393  * it has too few free inodes left (min_inodes) or
 394  * it has too few free blocks left (min_blocks) or
 395  * it's already running too large debt (max_debt).
 396  * Parent's group is preferred, if it doesn't satisfy these
 397  * conditions we search cyclically through the rest. If none
 398  * of the groups look good we just look for a group with more
 399  * free inodes than average (starting at parent's group).
 400  *
 401  * Debt is incremented each time we allocate a directory and decremented
 402  * when we allocate an inode, within 0--255.
 403  */
 404
 405 #define INODE_COST 64
 406 #define BLOCK_COST 256
 407
 408 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 409                                 ext4_group_t *group)
 410 {
 411         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 412         struct ext4_sb_info *sbi = EXT4_SB(sb);
 413         struct ext4_super_block *es = sbi->s_es;
 414         ext4_group_t ngroups = sbi->s_groups_count;
 415         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 416         unsigned int freei, avefreei;
 417         ext4_fsblk_t freeb, avefreeb;
 418         ext4_fsblk_t blocks_per_dir;
 419         unsigned int ndirs;
 420         int max_debt, max_dirs, min_inodes;
 421         ext4_grpblk_t min_blocks;
 422         ext4_group_t i;
 423         struct ext4_group_desc *desc;
 424
 425         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 426         avefreei = freei / ngroups;
 427         freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 428         avefreeb = freeb;
 429         do_div(avefreeb, ngroups);
 430         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 431
 432         if ((parent == sb->s_root->d_inode) ||
 433             (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
 434                 int best_ndir = inodes_per_group;
 435                 ext4_group_t grp;
 436                 int ret = -1;
 437
 438                 get_random_bytes(&grp, sizeof(grp));
 439                 parent_group = (unsigned)grp % ngroups;
 440                 for (i = 0; i < ngroups; i++) {
 441                         grp = (parent_group + i) % ngroups;
 442                         desc = ext4_get_group_desc(sb, grp, NULL);
 443                         if (!desc || !desc->bg_free_inodes_count)
 444                                 continue;
 445                         if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
 446                                 continue;
 447                         if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
 448                                 continue;
 449                         if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
 450                                 continue;
 451                         *group = grp;
 452                         ret = 0;
 453                         best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
 454                 }
 455                 if (ret == 0)
 456                         return ret;
 457                 goto fallback;
 458         }
 459
 460         blocks_per_dir = ext4_blocks_count(es) - freeb;
 461         do_div(blocks_per_dir, ndirs);
 462
 463         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 464         min_inodes = avefreei - inodes_per_group / 4;
 465         min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb) / 4;
 466
 467         max_debt = EXT4_BLOCKS_PER_GROUP(sb);
 468         max_debt /= max_t(int, blocks_per_dir, BLOCK_COST);
 469         if (max_debt * INODE_COST > inodes_per_group)
 470                 max_debt = inodes_per_group / INODE_COST;
 471         if (max_debt > 255)
 472                 max_debt = 255;
 473         if (max_debt == 0)
 474                 max_debt = 1;
 475
 476         for (i = 0; i < ngroups; i++) {
 477                 *group = (parent_group + i) % ngroups;
 478                 desc = ext4_get_group_desc(sb, *group, NULL);
 479                 if (!desc || !desc->bg_free_inodes_count)
 480                         continue;
 481                 if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
 482                         continue;
 483                 if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
 484                         continue;
 485                 if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
 486                         continue;
 487                 return 0;
 488         }
 489
 490 fallback:
 491         for (i = 0; i < ngroups; i++) {
 492                 *group = (parent_group + i) % ngroups;
 493                 desc = ext4_get_group_desc(sb, *group, NULL);
 494                 if (desc && desc->bg_free_inodes_count &&
 495                         le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
 496                         return 0;
 497         }
 498
 499         if (avefreei) {
 500                 /*
 501                  * The free-inodes counter is approximate, and for really small
 502                  * filesystems the above test can fail to find any blockgroups
 503                  */
 504                 avefreei = 0;
 505                 goto fallback;
 506         }
 507
 508         return -1;
 509 }
 510
 511 static int find_group_other(struct super_block *sb, struct inode *parent,
 512                                 ext4_group_t *group)
 513 {
 514         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 515         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 516         struct ext4_group_desc *desc;
 517         ext4_group_t i;
 518
 519         /*
 520          * Try to place the inode in its parent directory
 521          */
 522         *group = parent_group;
 523         desc = ext4_get_group_desc(sb, *group, NULL);
 524         if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 525                         le16_to_cpu(desc->bg_free_blocks_count))
 526                 return 0;
 527
 528         /*
 529          * We're going to place this inode in a different blockgroup from its
 530          * parent.  We want to cause files in a common directory to all land in
 531          * the same blockgroup.  But we want files which are in a different
 532          * directory which shares a blockgroup with our parent to land in a
 533          * different blockgroup.
 534          *
 535          * So add our directory's i_ino into the starting point for the hash.
 536          */
 537         *group = (*group + parent->i_ino) % ngroups;
 538
 539         /*
 540          * Use a quadratic hash to find a group with a free inode and some free
 541          * blocks.
 542          */
 543         for (i = 1; i < ngroups; i <<= 1) {
 544                 *group += i;
 545                 if (*group >= ngroups)
 546                         *group -= ngroups;
 547                 desc = ext4_get_group_desc(sb, *group, NULL);
 548                 if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 549                                 le16_to_cpu(desc->bg_free_blocks_count))
 550                         return 0;
 551         }
 552
 553         /*
 554          * That failed: try linear search for a free inode, even if that group
 555          * has no free blocks.
 556          */
 557         *group = parent_group;
 558         for (i = 0; i < ngroups; i++) {
 559                 if (++*group >= ngroups)
 560                         *group = 0;
 561                 desc = ext4_get_group_desc(sb, *group, NULL);
 562                 if (desc && le16_to_cpu(desc->bg_free_inodes_count))
 563                         return 0;
 564         }
 565
 566         return -1;
 567 }
 568
 569 /*
 570  * There are two policies for allocating an inode.  If the new inode is
 571  * a directory, then a forward search is made for a block group with both
 572  * free space and a low directory-to-inode ratio; if that fails, then of
 573  * the groups with above-average free space, that group with the fewest
 574  * directories already is chosen.
 575  *
 576  * For other inodes, search forward from the parent directory's block
 577  * group to find a free inode.
 578  */
 579 struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
 580 {
 581         struct super_block *sb;
 582         struct buffer_head *bitmap_bh = NULL;
 583         struct buffer_head *bh2;
 584         ext4_group_t group = 0;
 585         unsigned long ino = 0;
 586         struct inode * inode;
 587         struct ext4_group_desc * gdp = NULL;
 588         struct ext4_super_block * es;
 589         struct ext4_inode_info *ei;
 590         struct ext4_sb_info *sbi;
 591         int ret2, err = 0;
 592         struct inode *ret;
 593         ext4_group_t i;
 594         int free = 0;
 595         ext4_group_t flex_group;
 596
 597         /* Cannot create files in a deleted directory */
 598         if (!dir || !dir->i_nlink)
 599                 return ERR_PTR(-EPERM);
 600
 601         sb = dir->i_sb;
 602         inode = new_inode(sb);
 603         if (!inode)
 604                 return ERR_PTR(-ENOMEM);
 605         ei = EXT4_I(inode);
 606
 607         sbi = EXT4_SB(sb);
 608         es = sbi->s_es;
 609
 610         if (sbi->s_log_groups_per_flex) {
 611                 ret2 = find_group_flex(sb, dir, &group);
 612                 goto got_group;
 613         }
 614
 615         if (S_ISDIR(mode)) {
 616                 if (test_opt (sb, OLDALLOC))
 617                         ret2 = find_group_dir(sb, dir, &group);
 618                 else
 619                         ret2 = find_group_orlov(sb, dir, &group);
 620         } else
 621                 ret2 = find_group_other(sb, dir, &group);
 622
 623 got_group:
 624         err = -ENOSPC;
 625         if (ret2 == -1)
 626                 goto out;
 627
 628         for (i = 0; i < sbi->s_groups_count; i++) {
 629                 err = -EIO;
 630
 631                 gdp = ext4_get_group_desc(sb, group, &bh2);
 632                 if (!gdp)
 633                         goto fail;
 634
 635                 brelse(bitmap_bh);
 636                 bitmap_bh = ext4_read_inode_bitmap(sb, group);
 637                 if (!bitmap_bh)
 638                         goto fail;
 639
 640                 ino = 0;
 641
 642 repeat_in_this_group:
 643                 ino = ext4_find_next_zero_bit((unsigned long *)
 644                                 bitmap_bh->b_data, EXT4_INODES_PER_GROUP(sb), ino);
 645                 if (ino < EXT4_INODES_PER_GROUP(sb)) {
 646
 647                         BUFFER_TRACE(bitmap_bh, "get_write_access");
 648                         err = ext4_journal_get_write_access(handle, bitmap_bh);
 649                         if (err)
 650                                 goto fail;
 651
 652                         if (!ext4_set_bit_atomic(sb_bgl_lock(sbi, group),
 653                                                 ino, bitmap_bh->b_data)) {
 654                                 /* we won it */
 655                                 BUFFER_TRACE(bitmap_bh,
 656                                         "call ext4_journal_dirty_metadata");
 657                                 err = ext4_journal_dirty_metadata(handle,
 658                                                                 bitmap_bh);
 659                                 if (err)
 660                                         goto fail;
 661                                 goto got;
 662                         }
 663                         /* we lost it */
 664                         jbd2_journal_release_buffer(handle, bitmap_bh);
 665
 666                         if (++ino < EXT4_INODES_PER_GROUP(sb))
 667                                 goto repeat_in_this_group;
 668                 }
 669
 670                 /*
 671                  * This case is possible in concurrent environment.  It is very
 672                  * rare.  We cannot repeat the find_group_xxx() call because
 673                  * that will simply return the same blockgroup, because the
 674                  * group descriptor metadata has not yet been updated.
 675                  * So we just go onto the next blockgroup.
 676                  */
 677                 if (++group == sbi->s_groups_count)
 678                         group = 0;
 679         }
 680         err = -ENOSPC;
 681         goto out;
 682
 683 got:
 684         ino++;
 685         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
 686             ino > EXT4_INODES_PER_GROUP(sb)) {
 687                 ext4_error(sb, __func__,
 688                            "reserved inode or inode > inodes count - "
 689                            "block_group = %lu, inode=%lu", group,
 690                            ino + group * EXT4_INODES_PER_GROUP(sb));
 691                 err = -EIO;
 692                 goto fail;
 693         }
 694
 695         BUFFER_TRACE(bh2, "get_write_access");
 696         err = ext4_journal_get_write_access(handle, bh2);
 697         if (err) goto fail;
 698
 699         /* We may have to initialize the block bitmap if it isn't already */
 700         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
 701             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 702                 struct buffer_head *block_bh = ext4_read_block_bitmap(sb, group);
 703
 704                 BUFFER_TRACE(block_bh, "get block bitmap access");
 705                 err = ext4_journal_get_write_access(handle, block_bh);
 706                 if (err) {
 707                         brelse(block_bh);
 708                         goto fail;
 709                 }
 710
 711                 free = 0;
 712                 spin_lock(sb_bgl_lock(sbi, group));
 713                 /* recheck and clear flag under lock if we still need to */
 714                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 715                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 716                         free = ext4_free_blocks_after_init(sb, group, gdp);
 717                         gdp->bg_free_blocks_count = cpu_to_le16(free);
 718                 }
 719                 spin_unlock(sb_bgl_lock(sbi, group));
 720
 721                 /* Don't need to dirty bitmap block if we didn't change it */
 722                 if (free) {
 723                         BUFFER_TRACE(block_bh, "dirty block bitmap");
 724                         err = ext4_journal_dirty_metadata(handle, block_bh);
 725                 }
 726
 727                 brelse(block_bh);
 728                 if (err)
 729                         goto fail;
 730         }
 731
 732         spin_lock(sb_bgl_lock(sbi, group));
 733         /* If we didn't allocate from within the initialized part of the inode
 734          * table then we need to initialize up to this inode. */
 735         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 736                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 737                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 738
 739                         /* When marking the block group with
 740                          * ~EXT4_BG_INODE_UNINIT we don't want to depend
 741                          * on the value of bg_itable_unused even though
 742                          * mke2fs could have initialized the same for us.
 743                          * Instead we calculated the value below
 744                          */
 745
 746                         free = 0;
 747                 } else {
 748                         free = EXT4_INODES_PER_GROUP(sb) -
 749                                 le16_to_cpu(gdp->bg_itable_unused);
 750                 }
 751
 752                 /*
 753                  * Check the relative inode number against the last used
 754                  * relative inode number in this group. if it is greater
 755                  * we need to  update the bg_itable_unused count
 756                  *
 757                  */
 758                 if (ino > free)
 759                         gdp->bg_itable_unused =
 760                                 cpu_to_le16(EXT4_INODES_PER_GROUP(sb) - ino);
 761         }
 762
 763         le16_add_cpu(&gdp->bg_free_inodes_count, -1);
 764         if (S_ISDIR(mode)) {
 765                 le16_add_cpu(&gdp->bg_used_dirs_count, 1);
 766         }
 767         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
 768         spin_unlock(sb_bgl_lock(sbi, group));
 769         BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
 770         err = ext4_journal_dirty_metadata(handle, bh2);
 771         if (err) goto fail;
 772
 773         percpu_counter_dec(&sbi->s_freeinodes_counter);
 774         if (S_ISDIR(mode))
 775                 percpu_counter_inc(&sbi->s_dirs_counter);
 776         sb->s_dirt = 1;
 777
 778         if (sbi->s_log_groups_per_flex) {
 779                 flex_group = ext4_flex_group(sbi, group);
 780                 spin_lock(sb_bgl_lock(sbi, flex_group));
 781                 sbi->s_flex_groups[flex_group].free_inodes--;
 782                 spin_unlock(sb_bgl_lock(sbi, flex_group));
 783         }
 784
 785         inode->i_uid = current->fsuid;
 786         if (test_opt (sb, GRPID))
 787                 inode->i_gid = dir->i_gid;
 788         else if (dir->i_mode & S_ISGID) {
 789                 inode->i_gid = dir->i_gid;
 790                 if (S_ISDIR(mode))
 791                         mode |= S_ISGID;
 792         } else
 793                 inode->i_gid = current->fsgid;
 794         inode->i_mode = mode;
 795
 796         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
 797         /* This is the optimal IO size (for stat), not the fs block size */
 798         inode->i_blocks = 0;
 799         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
 800                                                        ext4_current_time(inode);
 801
 802         memset(ei->i_data, 0, sizeof(ei->i_data));
 803         ei->i_dir_start_lookup = 0;
 804         ei->i_disksize = 0;
 805
 806         /*
 807          * Don't inherit extent flag from directory. We set extent flag on
 808          * newly created directory and file only if -o extent mount option is
 809          * specified
 810          */
 811         ei->i_flags = EXT4_I(dir)->i_flags & ~(EXT4_INDEX_FL|EXT4_EXTENTS_FL);
 812         if (S_ISLNK(mode))
 813                 ei->i_flags &= ~(EXT4_IMMUTABLE_FL|EXT4_APPEND_FL);
 814         /* dirsync only applies to directories */
 815         if (!S_ISDIR(mode))
 816                 ei->i_flags &= ~EXT4_DIRSYNC_FL;
 817         ei->i_file_acl = 0;
 818         ei->i_dtime = 0;
 819         ei->i_block_alloc_info = NULL;
 820         ei->i_block_group = group;
 821
 822         ext4_set_inode_flags(inode);
 823         if (IS_DIRSYNC(inode))
 824                 handle->h_sync = 1;
 825         insert_inode_hash(inode);
 826         spin_lock(&sbi->s_next_gen_lock);
 827         inode->i_generation = sbi->s_next_generation++;
 828         spin_unlock(&sbi->s_next_gen_lock);
 829
 830         ei->i_state = EXT4_STATE_NEW;
 831
 832         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
 833
 834         ret = inode;
 835         if(DQUOT_ALLOC_INODE(inode)) {
 836                 err = -EDQUOT;
 837                 goto fail_drop;
 838         }
 839
 840         err = ext4_init_acl(handle, inode, dir);
 841         if (err)
 842                 goto fail_free_drop;
 843
 844         err = ext4_init_security(handle,inode, dir);
 845         if (err)
 846                 goto fail_free_drop;
 847
 848         if (test_opt(sb, EXTENTS)) {
 849                 /* set extent flag only for directory, file and normal symlink*/
 850                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
 851                         EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;
 852                         ext4_ext_tree_init(handle, inode);
 853                 }
 854         }
 855
 856         err = ext4_mark_inode_dirty(handle, inode);
 857         if (err) {
 858                 ext4_std_error(sb, err);
 859                 goto fail_free_drop;
 860         }
 861
 862         ext4_debug("allocating inode %lu\n", inode->i_ino);
 863         goto really_out;
 864 fail:
 865         ext4_std_error(sb, err);
 866 out:
 867         iput(inode);
 868         ret = ERR_PTR(err);
 869 really_out:
 870         brelse(bitmap_bh);
 871         return ret;
 872
 873 fail_free_drop:
 874         DQUOT_FREE_INODE(inode);
 875
 876 fail_drop:
 877         DQUOT_DROP(inode);
 878         inode->i_flags |= S_NOQUOTA;
 879         inode->i_nlink = 0;
 880         iput(inode);
 881         brelse(bitmap_bh);
 882         return ERR_PTR(err);
 883 }
 884
 885 /* Verify that we are loading a valid orphan from disk */
 886 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
 887 {
 888         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
 889         ext4_group_t block_group;
 890         int bit;
 891         struct buffer_head *bitmap_bh;
 892         struct inode *inode = NULL;
 893         long err = -EIO;
 894
 895         /* Error cases - e2fsck has already cleaned up for us */
 896         if (ino > max_ino) {
 897                 ext4_warning(sb, __func__,
 898                              "bad orphan ino %lu!  e2fsck was run?", ino);
 899                 goto error;
 900         }
 901
 902         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 903         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 904         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 905         if (!bitmap_bh) {
 906                 ext4_warning(sb, __func__,
 907                              "inode bitmap error for orphan %lu", ino);
 908                 goto error;
 909         }
 910
 911         /* Having the inode bit set should be a 100% indicator that this
 912          * is a valid orphan (no e2fsck run on fs).  Orphans also include
 913          * inodes that were being truncated, so we can't check i_nlink==0.
 914          */
 915         if (!ext4_test_bit(bit, bitmap_bh->b_data))
 916                 goto bad_orphan;
 917
 918         inode = ext4_iget(sb, ino);
 919         if (IS_ERR(inode))
 920                 goto iget_failed;
 921
 922         /*
 923          * If the orphans has i_nlinks > 0 then it should be able to be
 924          * truncated, otherwise it won't be removed from the orphan list
 925          * during processing and an infinite loop will result.
 926          */
 927         if (inode->i_nlink && !ext4_can_truncate(inode))
 928                 goto bad_orphan;
 929
 930         if (NEXT_ORPHAN(inode) > max_ino)
 931                 goto bad_orphan;
 932         brelse(bitmap_bh);
 933         return inode;
 934
 935 iget_failed:
 936         err = PTR_ERR(inode);
 937         inode = NULL;
 938 bad_orphan:
 939         ext4_warning(sb, __func__,
 940                      "bad orphan inode %lu!  e2fsck was run?", ino);
 941         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
 942                bit, (unsigned long long)bitmap_bh->b_blocknr,
 943                ext4_test_bit(bit, bitmap_bh->b_data));
 944         printk(KERN_NOTICE "inode=%p\n", inode);
 945         if (inode) {
 946                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
 947                        is_bad_inode(inode));
 948                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
 949                        NEXT_ORPHAN(inode));
 950                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
 951                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
 952                 /* Avoid freeing blocks if we got a bad deleted inode */
 953                 if (inode->i_nlink == 0)
 954                         inode->i_blocks = 0;
 955                 iput(inode);
 956         }
 957         brelse(bitmap_bh);
 958 error:
 959         return ERR_PTR(err);
 960 }
 961
 962 unsigned long ext4_count_free_inodes (struct super_block * sb)
 963 {
 964         unsigned long desc_count;
 965         struct ext4_group_desc *gdp;
 966         ext4_group_t i;
 967 #ifdef EXT4FS_DEBUG
 968         struct ext4_super_block *es;
 969         unsigned long bitmap_count, x;
 970         struct buffer_head *bitmap_bh = NULL;
 971
 972         es = EXT4_SB(sb)->s_es;
 973         desc_count = 0;
 974         bitmap_count = 0;
 975         gdp = NULL;
 976         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
 977                 gdp = ext4_get_group_desc (sb, i, NULL);
 978                 if (!gdp)
 979                         continue;
 980                 desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
 981                 brelse(bitmap_bh);
 982                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
 983                 if (!bitmap_bh)
 984                         continue;
 985
 986                 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
 987                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
 988                         i, le16_to_cpu(gdp->bg_free_inodes_count), x);
 989                 bitmap_count += x;
 990         }
 991         brelse(bitmap_bh);
 992         printk("ext4_count_free_inodes: stored = %u, computed = %lu, %lu\n",
 993                 le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
 994         return desc_count;
 995 #else
 996         desc_count = 0;
 997         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
 998                 gdp = ext4_get_group_desc (sb, i, NULL);
 999                 if (!gdp)
1000                         continue;
1001                 desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
1002                 cond_resched();
1003         }
1004         return desc_count;
1005 #endif
1006 }
1007
1008 /* Called at mount-time, super-block is locked */
1009 unsigned long ext4_count_dirs (struct super_block * sb)
1010 {
1011         unsigned long count = 0;
1012         ext4_group_t i;
1013
1014         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1015                 struct ext4_group_desc *gdp = ext4_get_group_desc (sb, i, NULL);
1016                 if (!gdp)
1017                         continue;
1018                 count += le16_to_cpu(gdp->bg_used_dirs_count);
1019         }
1020         return count;
1021 }
1022