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 (buffer_uptodate(bh) &&
 119             !(desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
 120                 return bh;
 121
 122         lock_buffer(bh);
 123         spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
 124         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 125                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
 126                 set_buffer_uptodate(bh);
 127                 unlock_buffer(bh);
 128                 spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
 129                 return bh;
 130         }
 131         spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
 132         if (bh_submit_read(bh) < 0) {
 133                 put_bh(bh);
 134                 ext4_error(sb, __func__,
 135                             "Cannot read inode bitmap - "
 136                             "block_group = %lu, inode_bitmap = %llu",
 137                             block_group, bitmap_blk);
 138                 return NULL;
 139         }
 140         return bh;
 141 }
 142
 143 /*
 144  * NOTE! When we get the inode, we're the only people
 145  * that have access to it, and as such there are no
 146  * race conditions we have to worry about. The inode
 147  * is not on the hash-lists, and it cannot be reached
 148  * through the filesystem because the directory entry
 149  * has been deleted earlier.
 150  *
 151  * HOWEVER: we must make sure that we get no aliases,
 152  * which means that we have to call "clear_inode()"
 153  * _before_ we mark the inode not in use in the inode
 154  * bitmaps. Otherwise a newly created file might use
 155  * the same inode number (not actually the same pointer
 156  * though), and then we'd have two inodes sharing the
 157  * same inode number and space on the harddisk.
 158  */
 159 void ext4_free_inode(handle_t *handle, struct inode *inode)
 160 {
 161         struct super_block *sb = inode->i_sb;
 162         int is_directory;
 163         unsigned long ino;
 164         struct buffer_head *bitmap_bh = NULL;
 165         struct buffer_head *bh2;
 166         ext4_group_t block_group;
 167         unsigned long bit;
 168         struct ext4_group_desc *gdp;
 169         struct ext4_super_block *es;
 170         struct ext4_sb_info *sbi;
 171         int fatal = 0, err;
 172         ext4_group_t flex_group;
 173
 174         if (atomic_read(&inode->i_count) > 1) {
 175                 printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
 176                        atomic_read(&inode->i_count));
 177                 return;
 178         }
 179         if (inode->i_nlink) {
 180                 printk(KERN_ERR "ext4_free_inode: inode has nlink=%d\n",
 181                        inode->i_nlink);
 182                 return;
 183         }
 184         if (!sb) {
 185                 printk(KERN_ERR "ext4_free_inode: inode on "
 186                        "nonexistent device\n");
 187                 return;
 188         }
 189         sbi = EXT4_SB(sb);
 190
 191         ino = inode->i_ino;
 192         ext4_debug("freeing inode %lu\n", ino);
 193
 194         /*
 195          * Note: we must free any quota before locking the superblock,
 196          * as writing the quota to disk may need the lock as well.
 197          */
 198         DQUOT_INIT(inode);
 199         ext4_xattr_delete_inode(handle, inode);
 200         DQUOT_FREE_INODE(inode);
 201         DQUOT_DROP(inode);
 202
 203         is_directory = S_ISDIR(inode->i_mode);
 204
 205         /* Do this BEFORE marking the inode not in use or returning an error */
 206         clear_inode(inode);
 207
 208         es = EXT4_SB(sb)->s_es;
 209         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 210                 ext4_error(sb, "ext4_free_inode",
 211                            "reserved or nonexistent inode %lu", ino);
 212                 goto error_return;
 213         }
 214         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 215         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 216         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 217         if (!bitmap_bh)
 218                 goto error_return;
 219
 220         BUFFER_TRACE(bitmap_bh, "get_write_access");
 221         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 222         if (fatal)
 223                 goto error_return;
 224
 225         /* Ok, now we can actually update the inode bitmaps.. */
 226         if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
 227                                         bit, bitmap_bh->b_data))
 228                 ext4_error(sb, "ext4_free_inode",
 229                            "bit already cleared for inode %lu", ino);
 230         else {
 231                 gdp = ext4_get_group_desc(sb, block_group, &bh2);
 232
 233                 BUFFER_TRACE(bh2, "get_write_access");
 234                 fatal = ext4_journal_get_write_access(handle, bh2);
 235                 if (fatal) goto error_return;
 236
 237                 if (gdp) {
 238                         spin_lock(sb_bgl_lock(sbi, block_group));
 239                         le16_add_cpu(&gdp->bg_free_inodes_count, 1);
 240                         if (is_directory)
 241                                 le16_add_cpu(&gdp->bg_used_dirs_count, -1);
 242                         gdp->bg_checksum = ext4_group_desc_csum(sbi,
 243                                                         block_group, gdp);
 244                         spin_unlock(sb_bgl_lock(sbi, block_group));
 245                         percpu_counter_inc(&sbi->s_freeinodes_counter);
 246                         if (is_directory)
 247                                 percpu_counter_dec(&sbi->s_dirs_counter);
 248
 249                         if (sbi->s_log_groups_per_flex) {
 250                                 flex_group = ext4_flex_group(sbi, block_group);
 251                                 spin_lock(sb_bgl_lock(sbi, flex_group));
 252                                 sbi->s_flex_groups[flex_group].free_inodes++;
 253                                 spin_unlock(sb_bgl_lock(sbi, flex_group));
 254                         }
 255                 }
 256                 BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
 257                 err = ext4_journal_dirty_metadata(handle, bh2);
 258                 if (!fatal) fatal = err;
 259         }
 260         BUFFER_TRACE(bitmap_bh, "call ext4_journal_dirty_metadata");
 261         err = ext4_journal_dirty_metadata(handle, bitmap_bh);
 262         if (!fatal)
 263                 fatal = err;
 264         sb->s_dirt = 1;
 265 error_return:
 266         brelse(bitmap_bh);
 267         ext4_std_error(sb, fatal);
 268 }
 269
 270 /*
 271  * There are two policies for allocating an inode.  If the new inode is
 272  * a directory, then a forward search is made for a block group with both
 273  * free space and a low directory-to-inode ratio; if that fails, then of
 274  * the groups with above-average free space, that group with the fewest
 275  * directories already is chosen.
 276  *
 277  * For other inodes, search forward from the parent directory\'s block
 278  * group to find a free inode.
 279  */
 280 static int find_group_dir(struct super_block *sb, struct inode *parent,
 281                                 ext4_group_t *best_group)
 282 {
 283         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 284         unsigned int freei, avefreei;
 285         struct ext4_group_desc *desc, *best_desc = NULL;
 286         ext4_group_t group;
 287         int ret = -1;
 288
 289         freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
 290         avefreei = freei / ngroups;
 291
 292         for (group = 0; group < ngroups; group++) {
 293                 desc = ext4_get_group_desc(sb, group, NULL);
 294                 if (!desc || !desc->bg_free_inodes_count)
 295                         continue;
 296                 if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
 297                         continue;
 298                 if (!best_desc ||
 299                     (le16_to_cpu(desc->bg_free_blocks_count) >
 300                      le16_to_cpu(best_desc->bg_free_blocks_count))) {
 301                         *best_group = group;
 302                         best_desc = desc;
 303                         ret = 0;
 304                 }
 305         }
 306         return ret;
 307 }
 308
 309 #define free_block_ratio 10
 310
 311 static int find_group_flex(struct super_block *sb, struct inode *parent,
 312                            ext4_group_t *best_group)
 313 {
 314         struct ext4_sb_info *sbi = EXT4_SB(sb);
 315         struct ext4_group_desc *desc;
 316         struct buffer_head *bh;
 317         struct flex_groups *flex_group = sbi->s_flex_groups;
 318         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 319         ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
 320         ext4_group_t ngroups = sbi->s_groups_count;
 321         int flex_size = ext4_flex_bg_size(sbi);
 322         ext4_group_t best_flex = parent_fbg_group;
 323         int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
 324         int flexbg_free_blocks;
 325         int flex_freeb_ratio;
 326         ext4_group_t n_fbg_groups;
 327         ext4_group_t i;
 328
 329         n_fbg_groups = (sbi->s_groups_count + flex_size - 1) >>
 330                 sbi->s_log_groups_per_flex;
 331
 332 find_close_to_parent:
 333         flexbg_free_blocks = flex_group[best_flex].free_blocks;
 334         flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 335         if (flex_group[best_flex].free_inodes &&
 336             flex_freeb_ratio > free_block_ratio)
 337                 goto found_flexbg;
 338
 339         if (best_flex && best_flex == parent_fbg_group) {
 340                 best_flex--;
 341                 goto find_close_to_parent;
 342         }
 343
 344         for (i = 0; i < n_fbg_groups; i++) {
 345                 if (i == parent_fbg_group || i == parent_fbg_group - 1)
 346                         continue;
 347
 348                 flexbg_free_blocks = flex_group[i].free_blocks;
 349                 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 350
 351                 if (flex_freeb_ratio > free_block_ratio &&
 352                     flex_group[i].free_inodes) {
 353                         best_flex = i;
 354                         goto found_flexbg;
 355                 }
 356
 357                 if (flex_group[best_flex].free_inodes == 0 ||
 358                     (flex_group[i].free_blocks >
 359                      flex_group[best_flex].free_blocks &&
 360                      flex_group[i].free_inodes))
 361                         best_flex = i;
 362         }
 363
 364         if (!flex_group[best_flex].free_inodes ||
 365             !flex_group[best_flex].free_blocks)
 366                 return -1;
 367
 368 found_flexbg:
 369         for (i = best_flex * flex_size; i < ngroups &&
 370                      i < (best_flex + 1) * flex_size; i++) {
 371                 desc = ext4_get_group_desc(sb, i, &bh);
 372                 if (le16_to_cpu(desc->bg_free_inodes_count)) {
 373                         *best_group = i;
 374                         goto out;
 375                 }
 376         }
 377
 378         return -1;
 379 out:
 380         return 0;
 381 }
 382
 383 /*
 384  * Orlov's allocator for directories.
 385  *
 386  * We always try to spread first-level directories.
 387  *
 388  * If there are blockgroups with both free inodes and free blocks counts
 389  * not worse than average we return one with smallest directory count.
 390  * Otherwise we simply return a random group.
 391  *
 392  * For the rest rules look so:
 393  *
 394  * It's OK to put directory into a group unless
 395  * it has too many directories already (max_dirs) or
 396  * it has too few free inodes left (min_inodes) or
 397  * it has too few free blocks left (min_blocks) or
 398  * it's already running too large debt (max_debt).
 399  * Parent's group is preferred, if it doesn't satisfy these
 400  * conditions we search cyclically through the rest. If none
 401  * of the groups look good we just look for a group with more
 402  * free inodes than average (starting at parent's group).
 403  *
 404  * Debt is incremented each time we allocate a directory and decremented
 405  * when we allocate an inode, within 0--255.
 406  */
 407
 408 #define INODE_COST 64
 409 #define BLOCK_COST 256
 410
 411 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 412                                 ext4_group_t *group)
 413 {
 414         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 415         struct ext4_sb_info *sbi = EXT4_SB(sb);
 416         struct ext4_super_block *es = sbi->s_es;
 417         ext4_group_t ngroups = sbi->s_groups_count;
 418         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 419         unsigned int freei, avefreei;
 420         ext4_fsblk_t freeb, avefreeb;
 421         ext4_fsblk_t blocks_per_dir;
 422         unsigned int ndirs;
 423         int max_debt, max_dirs, min_inodes;
 424         ext4_grpblk_t min_blocks;
 425         ext4_group_t i;
 426         struct ext4_group_desc *desc;
 427
 428         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 429         avefreei = freei / ngroups;
 430         freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 431         avefreeb = freeb;
 432         do_div(avefreeb, ngroups);
 433         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 434
 435         if ((parent == sb->s_root->d_inode) ||
 436             (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
 437                 int best_ndir = inodes_per_group;
 438                 ext4_group_t grp;
 439                 int ret = -1;
 440
 441                 get_random_bytes(&grp, sizeof(grp));
 442                 parent_group = (unsigned)grp % ngroups;
 443                 for (i = 0; i < ngroups; i++) {
 444                         grp = (parent_group + i) % ngroups;
 445                         desc = ext4_get_group_desc(sb, grp, NULL);
 446                         if (!desc || !desc->bg_free_inodes_count)
 447                                 continue;
 448                         if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
 449                                 continue;
 450                         if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
 451                                 continue;
 452                         if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
 453                                 continue;
 454                         *group = grp;
 455                         ret = 0;
 456                         best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
 457                 }
 458                 if (ret == 0)
 459                         return ret;
 460                 goto fallback;
 461         }
 462
 463         blocks_per_dir = ext4_blocks_count(es) - freeb;
 464         do_div(blocks_per_dir, ndirs);
 465
 466         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 467         min_inodes = avefreei - inodes_per_group / 4;
 468         min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb) / 4;
 469
 470         max_debt = EXT4_BLOCKS_PER_GROUP(sb);
 471         max_debt /= max_t(int, blocks_per_dir, BLOCK_COST);
 472         if (max_debt * INODE_COST > inodes_per_group)
 473                 max_debt = inodes_per_group / INODE_COST;
 474         if (max_debt > 255)
 475                 max_debt = 255;
 476         if (max_debt == 0)
 477                 max_debt = 1;
 478
 479         for (i = 0; i < ngroups; i++) {
 480                 *group = (parent_group + i) % ngroups;
 481                 desc = ext4_get_group_desc(sb, *group, NULL);
 482                 if (!desc || !desc->bg_free_inodes_count)
 483                         continue;
 484                 if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
 485                         continue;
 486                 if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
 487                         continue;
 488                 if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
 489                         continue;
 490                 return 0;
 491         }
 492
 493 fallback:
 494         for (i = 0; i < ngroups; i++) {
 495                 *group = (parent_group + i) % ngroups;
 496                 desc = ext4_get_group_desc(sb, *group, NULL);
 497                 if (desc && desc->bg_free_inodes_count &&
 498                         le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
 499                         return 0;
 500         }
 501
 502         if (avefreei) {
 503                 /*
 504                  * The free-inodes counter is approximate, and for really small
 505                  * filesystems the above test can fail to find any blockgroups
 506                  */
 507                 avefreei = 0;
 508                 goto fallback;
 509         }
 510
 511         return -1;
 512 }
 513
 514 static int find_group_other(struct super_block *sb, struct inode *parent,
 515                                 ext4_group_t *group)
 516 {
 517         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 518         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 519         struct ext4_group_desc *desc;
 520         ext4_group_t i;
 521
 522         /*
 523          * Try to place the inode in its parent directory
 524          */
 525         *group = parent_group;
 526         desc = ext4_get_group_desc(sb, *group, NULL);
 527         if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 528                         le16_to_cpu(desc->bg_free_blocks_count))
 529                 return 0;
 530
 531         /*
 532          * We're going to place this inode in a different blockgroup from its
 533          * parent.  We want to cause files in a common directory to all land in
 534          * the same blockgroup.  But we want files which are in a different
 535          * directory which shares a blockgroup with our parent to land in a
 536          * different blockgroup.
 537          *
 538          * So add our directory's i_ino into the starting point for the hash.
 539          */
 540         *group = (*group + parent->i_ino) % ngroups;
 541
 542         /*
 543          * Use a quadratic hash to find a group with a free inode and some free
 544          * blocks.
 545          */
 546         for (i = 1; i < ngroups; i <<= 1) {
 547                 *group += i;
 548                 if (*group >= ngroups)
 549                         *group -= ngroups;
 550                 desc = ext4_get_group_desc(sb, *group, NULL);
 551                 if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 552                                 le16_to_cpu(desc->bg_free_blocks_count))
 553                         return 0;
 554         }
 555
 556         /*
 557          * That failed: try linear search for a free inode, even if that group
 558          * has no free blocks.
 559          */
 560         *group = parent_group;
 561         for (i = 0; i < ngroups; i++) {
 562                 if (++*group >= ngroups)
 563                         *group = 0;
 564                 desc = ext4_get_group_desc(sb, *group, NULL);
 565                 if (desc && le16_to_cpu(desc->bg_free_inodes_count))
 566                         return 0;
 567         }
 568
 569         return -1;
 570 }
 571
 572 /*
 573  * There are two policies for allocating an inode.  If the new inode is
 574  * a directory, then a forward search is made for a block group with both
 575  * free space and a low directory-to-inode ratio; if that fails, then of
 576  * the groups with above-average free space, that group with the fewest
 577  * directories already is chosen.
 578  *
 579  * For other inodes, search forward from the parent directory's block
 580  * group to find a free inode.
 581  */
 582 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
 583 {
 584         struct super_block *sb;
 585         struct buffer_head *bitmap_bh = NULL;
 586         struct buffer_head *bh2;
 587         ext4_group_t group = 0;
 588         unsigned long ino = 0;
 589         struct inode *inode;
 590         struct ext4_group_desc *gdp = NULL;
 591         struct ext4_super_block *es;
 592         struct ext4_inode_info *ei;
 593         struct ext4_sb_info *sbi;
 594         int ret2, err = 0;
 595         struct inode *ret;
 596         ext4_group_t i;
 597         int free = 0;
 598         ext4_group_t flex_group;
 599
 600         /* Cannot create files in a deleted directory */
 601         if (!dir || !dir->i_nlink)
 602                 return ERR_PTR(-EPERM);
 603
 604         sb = dir->i_sb;
 605         inode = new_inode(sb);
 606         if (!inode)
 607                 return ERR_PTR(-ENOMEM);
 608         ei = EXT4_I(inode);
 609
 610         sbi = EXT4_SB(sb);
 611         es = sbi->s_es;
 612
 613         if (sbi->s_log_groups_per_flex) {
 614                 ret2 = find_group_flex(sb, dir, &group);
 615                 goto got_group;
 616         }
 617
 618         if (S_ISDIR(mode)) {
 619                 if (test_opt(sb, OLDALLOC))
 620                         ret2 = find_group_dir(sb, dir, &group);
 621                 else
 622                         ret2 = find_group_orlov(sb, dir, &group);
 623         } else
 624                 ret2 = find_group_other(sb, dir, &group);
 625
 626 got_group:
 627         err = -ENOSPC;
 628         if (ret2 == -1)
 629                 goto out;
 630
 631         for (i = 0; i < sbi->s_groups_count; i++) {
 632                 err = -EIO;
 633
 634                 gdp = ext4_get_group_desc(sb, group, &bh2);
 635                 if (!gdp)
 636                         goto fail;
 637
 638                 brelse(bitmap_bh);
 639                 bitmap_bh = ext4_read_inode_bitmap(sb, group);
 640                 if (!bitmap_bh)
 641                         goto fail;
 642
 643                 ino = 0;
 644
 645 repeat_in_this_group:
 646                 ino = ext4_find_next_zero_bit((unsigned long *)
 647                                 bitmap_bh->b_data, EXT4_INODES_PER_GROUP(sb), ino);
 648                 if (ino < EXT4_INODES_PER_GROUP(sb)) {
 649
 650                         BUFFER_TRACE(bitmap_bh, "get_write_access");
 651                         err = ext4_journal_get_write_access(handle, bitmap_bh);
 652                         if (err)
 653                                 goto fail;
 654
 655                         if (!ext4_set_bit_atomic(sb_bgl_lock(sbi, group),
 656                                                 ino, bitmap_bh->b_data)) {
 657                                 /* we won it */
 658                                 BUFFER_TRACE(bitmap_bh,
 659                                         "call ext4_journal_dirty_metadata");
 660                                 err = ext4_journal_dirty_metadata(handle,
 661                                                                 bitmap_bh);
 662                                 if (err)
 663                                         goto fail;
 664                                 goto got;
 665                         }
 666                         /* we lost it */
 667                         jbd2_journal_release_buffer(handle, bitmap_bh);
 668
 669                         if (++ino < EXT4_INODES_PER_GROUP(sb))
 670                                 goto repeat_in_this_group;
 671                 }
 672
 673                 /*
 674                  * This case is possible in concurrent environment.  It is very
 675                  * rare.  We cannot repeat the find_group_xxx() call because
 676                  * that will simply return the same blockgroup, because the
 677                  * group descriptor metadata has not yet been updated.
 678                  * So we just go onto the next blockgroup.
 679                  */
 680                 if (++group == sbi->s_groups_count)
 681                         group = 0;
 682         }
 683         err = -ENOSPC;
 684         goto out;
 685
 686 got:
 687         ino++;
 688         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
 689             ino > EXT4_INODES_PER_GROUP(sb)) {
 690                 ext4_error(sb, __func__,
 691                            "reserved inode or inode > inodes count - "
 692                            "block_group = %lu, inode=%lu", group,
 693                            ino + group * EXT4_INODES_PER_GROUP(sb));
 694                 err = -EIO;
 695                 goto fail;
 696         }
 697
 698         BUFFER_TRACE(bh2, "get_write_access");
 699         err = ext4_journal_get_write_access(handle, bh2);
 700         if (err) goto fail;
 701
 702         /* We may have to initialize the block bitmap if it isn't already */
 703         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
 704             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 705                 struct buffer_head *block_bh = ext4_read_block_bitmap(sb, group);
 706
 707                 BUFFER_TRACE(block_bh, "get block bitmap access");
 708                 err = ext4_journal_get_write_access(handle, block_bh);
 709                 if (err) {
 710                         brelse(block_bh);
 711                         goto fail;
 712                 }
 713
 714                 free = 0;
 715                 spin_lock(sb_bgl_lock(sbi, group));
 716                 /* recheck and clear flag under lock if we still need to */
 717                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 718                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 719                         free = ext4_free_blocks_after_init(sb, group, gdp);
 720                         gdp->bg_free_blocks_count = cpu_to_le16(free);
 721                         gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
 722                                                                 gdp);
 723                 }
 724                 spin_unlock(sb_bgl_lock(sbi, group));
 725
 726                 /* Don't need to dirty bitmap block if we didn't change it */
 727                 if (free) {
 728                         BUFFER_TRACE(block_bh, "dirty block bitmap");
 729                         err = ext4_journal_dirty_metadata(handle, block_bh);
 730                 }
 731
 732                 brelse(block_bh);
 733                 if (err)
 734                         goto fail;
 735         }
 736
 737         spin_lock(sb_bgl_lock(sbi, group));
 738         /* If we didn't allocate from within the initialized part of the inode
 739          * table then we need to initialize up to this inode. */
 740         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 741                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 742                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 743
 744                         /* When marking the block group with
 745                          * ~EXT4_BG_INODE_UNINIT we don't want to depend
 746                          * on the value of bg_itable_unused even though
 747                          * mke2fs could have initialized the same for us.
 748                          * Instead we calculated the value below
 749                          */
 750
 751                         free = 0;
 752                 } else {
 753                         free = EXT4_INODES_PER_GROUP(sb) -
 754                                 le16_to_cpu(gdp->bg_itable_unused);
 755                 }
 756
 757                 /*
 758                  * Check the relative inode number against the last used
 759                  * relative inode number in this group. if it is greater
 760                  * we need to  update the bg_itable_unused count
 761                  *
 762                  */
 763                 if (ino > free)
 764                         gdp->bg_itable_unused =
 765                                 cpu_to_le16(EXT4_INODES_PER_GROUP(sb) - ino);
 766         }
 767
 768         le16_add_cpu(&gdp->bg_free_inodes_count, -1);
 769         if (S_ISDIR(mode)) {
 770                 le16_add_cpu(&gdp->bg_used_dirs_count, 1);
 771         }
 772         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
 773         spin_unlock(sb_bgl_lock(sbi, group));
 774         BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
 775         err = ext4_journal_dirty_metadata(handle, bh2);
 776         if (err) goto fail;
 777
 778         percpu_counter_dec(&sbi->s_freeinodes_counter);
 779         if (S_ISDIR(mode))
 780                 percpu_counter_inc(&sbi->s_dirs_counter);
 781         sb->s_dirt = 1;
 782
 783         if (sbi->s_log_groups_per_flex) {
 784                 flex_group = ext4_flex_group(sbi, group);
 785                 spin_lock(sb_bgl_lock(sbi, flex_group));
 786                 sbi->s_flex_groups[flex_group].free_inodes--;
 787                 spin_unlock(sb_bgl_lock(sbi, flex_group));
 788         }
 789
 790         inode->i_uid = current->fsuid;
 791         if (test_opt(sb, GRPID))
 792                 inode->i_gid = dir->i_gid;
 793         else if (dir->i_mode & S_ISGID) {
 794                 inode->i_gid = dir->i_gid;
 795                 if (S_ISDIR(mode))
 796                         mode |= S_ISGID;
 797         } else
 798                 inode->i_gid = current->fsgid;
 799         inode->i_mode = mode;
 800
 801         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
 802         /* This is the optimal IO size (for stat), not the fs block size */
 803         inode->i_blocks = 0;
 804         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
 805                                                        ext4_current_time(inode);
 806
 807         memset(ei->i_data, 0, sizeof(ei->i_data));
 808         ei->i_dir_start_lookup = 0;
 809         ei->i_disksize = 0;
 810
 811         /*
 812          * Don't inherit extent flag from directory. We set extent flag on
 813          * newly created directory and file only if -o extent mount option is
 814          * specified
 815          */
 816         ei->i_flags = EXT4_I(dir)->i_flags & ~(EXT4_INDEX_FL|EXT4_EXTENTS_FL);
 817         if (S_ISLNK(mode))
 818                 ei->i_flags &= ~(EXT4_IMMUTABLE_FL|EXT4_APPEND_FL);
 819         /* dirsync only applies to directories */
 820         if (!S_ISDIR(mode))
 821                 ei->i_flags &= ~EXT4_DIRSYNC_FL;
 822         ei->i_file_acl = 0;
 823         ei->i_dtime = 0;
 824         ei->i_block_group = group;
 825
 826         ext4_set_inode_flags(inode);
 827         if (IS_DIRSYNC(inode))
 828                 handle->h_sync = 1;
 829         insert_inode_hash(inode);
 830         spin_lock(&sbi->s_next_gen_lock);
 831         inode->i_generation = sbi->s_next_generation++;
 832         spin_unlock(&sbi->s_next_gen_lock);
 833
 834         ei->i_state = EXT4_STATE_NEW;
 835
 836         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
 837
 838         ret = inode;
 839         if (DQUOT_ALLOC_INODE(inode)) {
 840                 err = -EDQUOT;
 841                 goto fail_drop;
 842         }
 843
 844         err = ext4_init_acl(handle, inode, dir);
 845         if (err)
 846                 goto fail_free_drop;
 847
 848         err = ext4_init_security(handle, inode, dir);
 849         if (err)
 850                 goto fail_free_drop;
 851
 852         if (test_opt(sb, EXTENTS)) {
 853                 /* set extent flag only for directory, file and normal symlink*/
 854                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
 855                         EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;
 856                         ext4_ext_tree_init(handle, inode);
 857                 }
 858         }
 859
 860         err = ext4_mark_inode_dirty(handle, inode);
 861         if (err) {
 862                 ext4_std_error(sb, err);
 863                 goto fail_free_drop;
 864         }
 865
 866         ext4_debug("allocating inode %lu\n", inode->i_ino);
 867         goto really_out;
 868 fail:
 869         ext4_std_error(sb, err);
 870 out:
 871         iput(inode);
 872         ret = ERR_PTR(err);
 873 really_out:
 874         brelse(bitmap_bh);
 875         return ret;
 876
 877 fail_free_drop:
 878         DQUOT_FREE_INODE(inode);
 879
 880 fail_drop:
 881         DQUOT_DROP(inode);
 882         inode->i_flags |= S_NOQUOTA;
 883         inode->i_nlink = 0;
 884         iput(inode);
 885         brelse(bitmap_bh);
 886         return ERR_PTR(err);
 887 }
 888
 889 /* Verify that we are loading a valid orphan from disk */
 890 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
 891 {
 892         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
 893         ext4_group_t block_group;
 894         int bit;
 895         struct buffer_head *bitmap_bh;
 896         struct inode *inode = NULL;
 897         long err = -EIO;
 898
 899         /* Error cases - e2fsck has already cleaned up for us */
 900         if (ino > max_ino) {
 901                 ext4_warning(sb, __func__,
 902                              "bad orphan ino %lu!  e2fsck was run?", ino);
 903                 goto error;
 904         }
 905
 906         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 907         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 908         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 909         if (!bitmap_bh) {
 910                 ext4_warning(sb, __func__,
 911                              "inode bitmap error for orphan %lu", ino);
 912                 goto error;
 913         }
 914
 915         /* Having the inode bit set should be a 100% indicator that this
 916          * is a valid orphan (no e2fsck run on fs).  Orphans also include
 917          * inodes that were being truncated, so we can't check i_nlink==0.
 918          */
 919         if (!ext4_test_bit(bit, bitmap_bh->b_data))
 920                 goto bad_orphan;
 921
 922         inode = ext4_iget(sb, ino);
 923         if (IS_ERR(inode))
 924                 goto iget_failed;
 925
 926         /*
 927          * If the orphans has i_nlinks > 0 then it should be able to be
 928          * truncated, otherwise it won't be removed from the orphan list
 929          * during processing and an infinite loop will result.
 930          */
 931         if (inode->i_nlink && !ext4_can_truncate(inode))
 932                 goto bad_orphan;
 933
 934         if (NEXT_ORPHAN(inode) > max_ino)
 935                 goto bad_orphan;
 936         brelse(bitmap_bh);
 937         return inode;
 938
 939 iget_failed:
 940         err = PTR_ERR(inode);
 941         inode = NULL;
 942 bad_orphan:
 943         ext4_warning(sb, __func__,
 944                      "bad orphan inode %lu!  e2fsck was run?", ino);
 945         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
 946                bit, (unsigned long long)bitmap_bh->b_blocknr,
 947                ext4_test_bit(bit, bitmap_bh->b_data));
 948         printk(KERN_NOTICE "inode=%p\n", inode);
 949         if (inode) {
 950                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
 951                        is_bad_inode(inode));
 952                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
 953                        NEXT_ORPHAN(inode));
 954                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
 955                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
 956                 /* Avoid freeing blocks if we got a bad deleted inode */
 957                 if (inode->i_nlink == 0)
 958                         inode->i_blocks = 0;
 959                 iput(inode);
 960         }
 961         brelse(bitmap_bh);
 962 error:
 963         return ERR_PTR(err);
 964 }
 965
 966 unsigned long ext4_count_free_inodes(struct super_block *sb)
 967 {
 968         unsigned long desc_count;
 969         struct ext4_group_desc *gdp;
 970         ext4_group_t i;
 971 #ifdef EXT4FS_DEBUG
 972         struct ext4_super_block *es;
 973         unsigned long bitmap_count, x;
 974         struct buffer_head *bitmap_bh = NULL;
 975
 976         es = EXT4_SB(sb)->s_es;
 977         desc_count = 0;
 978         bitmap_count = 0;
 979         gdp = NULL;
 980         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
 981                 gdp = ext4_get_group_desc(sb, i, NULL);
 982                 if (!gdp)
 983                         continue;
 984                 desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
 985                 brelse(bitmap_bh);
 986                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
 987                 if (!bitmap_bh)
 988                         continue;
 989
 990                 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
 991                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
 992                         i, le16_to_cpu(gdp->bg_free_inodes_count), x);
 993                 bitmap_count += x;
 994         }
 995         brelse(bitmap_bh);
 996         printk(KERN_DEBUG "ext4_count_free_inodes: "
 997                "stored = %u, computed = %lu, %lu\n",
 998                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
 999         return desc_count;
1000 #else
1001         desc_count = 0;
1002         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1003                 gdp = ext4_get_group_desc(sb, i, NULL);
1004                 if (!gdp)
1005                         continue;
1006                 desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
1007                 cond_resched();
1008         }
1009         return desc_count;
1010 #endif
1011 }
1012
1013 /* Called at mount-time, super-block is locked */
1014 unsigned long ext4_count_dirs(struct super_block * sb)
1015 {
1016         unsigned long count = 0;
1017         ext4_group_t i;
1018
1019         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1020                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1021                 if (!gdp)
1022                         continue;
1023                 count += le16_to_cpu(gdp->bg_used_dirs_count);
1024         }
1025         return count;
1026 }
1027