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 %u",
  78                            block_group);
  79                 ext4_free_blks_set(sb, gdp, 0);
  80                 ext4_free_inodes_set(sb, gdp, 0);
  81                 ext4_itable_unused_set(sb, gdp, 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), sb->s_blocksize * 8,
  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 = %u, inode_bitmap = %llu",
 115                             block_group, bitmap_blk);
 116                 return NULL;
 117         }
 118         if (bitmap_uptodate(bh))
 119                 return bh;
 120
 121         lock_buffer(bh);
 122         if (bitmap_uptodate(bh)) {
 123                 unlock_buffer(bh);
 124                 return bh;
 125         }
 126         spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
 127         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 128                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
 129                 set_bitmap_uptodate(bh);
 130                 set_buffer_uptodate(bh);
 131                 spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
 132                 unlock_buffer(bh);
 133                 return bh;
 134         }
 135         spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
 136         if (buffer_uptodate(bh)) {
 137                 /*
 138                  * if not uninit if bh is uptodate,
 139                  * bitmap is also uptodate
 140                  */
 141                 set_bitmap_uptodate(bh);
 142                 unlock_buffer(bh);
 143                 return bh;
 144         }
 145         /*
 146          * submit the buffer_head for read. We can
 147          * safely mark the bitmap as uptodate now.
 148          * We do it here so the bitmap uptodate bit
 149          * get set with buffer lock held.
 150          */
 151         set_bitmap_uptodate(bh);
 152         if (bh_submit_read(bh) < 0) {
 153                 put_bh(bh);
 154                 ext4_error(sb, __func__,
 155                             "Cannot read inode bitmap - "
 156                             "block_group = %u, inode_bitmap = %llu",
 157                             block_group, bitmap_blk);
 158                 return NULL;
 159         }
 160         return bh;
 161 }
 162
 163 /*
 164  * NOTE! When we get the inode, we're the only people
 165  * that have access to it, and as such there are no
 166  * race conditions we have to worry about. The inode
 167  * is not on the hash-lists, and it cannot be reached
 168  * through the filesystem because the directory entry
 169  * has been deleted earlier.
 170  *
 171  * HOWEVER: we must make sure that we get no aliases,
 172  * which means that we have to call "clear_inode()"
 173  * _before_ we mark the inode not in use in the inode
 174  * bitmaps. Otherwise a newly created file might use
 175  * the same inode number (not actually the same pointer
 176  * though), and then we'd have two inodes sharing the
 177  * same inode number and space on the harddisk.
 178  */
 179 void ext4_free_inode(handle_t *handle, struct inode *inode)
 180 {
 181         struct super_block *sb = inode->i_sb;
 182         int is_directory;
 183         unsigned long ino;
 184         struct buffer_head *bitmap_bh = NULL;
 185         struct buffer_head *bh2;
 186         ext4_group_t block_group;
 187         unsigned long bit;
 188         struct ext4_group_desc *gdp;
 189         struct ext4_super_block *es;
 190         struct ext4_sb_info *sbi;
 191         int fatal = 0, err, count, cleared;
 192         ext4_group_t flex_group;
 193
 194         if (atomic_read(&inode->i_count) > 1) {
 195                 printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
 196                        atomic_read(&inode->i_count));
 197                 return;
 198         }
 199         if (inode->i_nlink) {
 200                 printk(KERN_ERR "ext4_free_inode: inode has nlink=%d\n",
 201                        inode->i_nlink);
 202                 return;
 203         }
 204         if (!sb) {
 205                 printk(KERN_ERR "ext4_free_inode: inode on "
 206                        "nonexistent device\n");
 207                 return;
 208         }
 209         sbi = EXT4_SB(sb);
 210
 211         ino = inode->i_ino;
 212         ext4_debug("freeing inode %lu\n", ino);
 213         trace_mark(ext4_free_inode,
 214                    "dev %s ino %lu mode %d uid %lu gid %lu bocks %llu",
 215                    sb->s_id, inode->i_ino, inode->i_mode,
 216                    (unsigned long) inode->i_uid, (unsigned long) inode->i_gid,
 217                    (unsigned long long) inode->i_blocks);
 218
 219         /*
 220          * Note: we must free any quota before locking the superblock,
 221          * as writing the quota to disk may need the lock as well.
 222          */
 223         DQUOT_INIT(inode);
 224         ext4_xattr_delete_inode(handle, inode);
 225         DQUOT_FREE_INODE(inode);
 226         DQUOT_DROP(inode);
 227
 228         is_directory = S_ISDIR(inode->i_mode);
 229
 230         /* Do this BEFORE marking the inode not in use or returning an error */
 231         clear_inode(inode);
 232
 233         es = EXT4_SB(sb)->s_es;
 234         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 235                 ext4_error(sb, "ext4_free_inode",
 236                            "reserved or nonexistent inode %lu", ino);
 237                 goto error_return;
 238         }
 239         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 240         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 241         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 242         if (!bitmap_bh)
 243                 goto error_return;
 244
 245         BUFFER_TRACE(bitmap_bh, "get_write_access");
 246         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 247         if (fatal)
 248                 goto error_return;
 249
 250         /* Ok, now we can actually update the inode bitmaps.. */
 251         spin_lock(sb_bgl_lock(sbi, block_group));
 252         cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
 253         spin_unlock(sb_bgl_lock(sbi, block_group));
 254         if (!cleared)
 255                 ext4_error(sb, "ext4_free_inode",
 256                            "bit already cleared for inode %lu", ino);
 257         else {
 258                 gdp = ext4_get_group_desc(sb, block_group, &bh2);
 259
 260                 BUFFER_TRACE(bh2, "get_write_access");
 261                 fatal = ext4_journal_get_write_access(handle, bh2);
 262                 if (fatal) goto error_return;
 263
 264                 if (gdp) {
 265                         spin_lock(sb_bgl_lock(sbi, block_group));
 266                         count = ext4_free_inodes_count(sb, gdp) + 1;
 267                         ext4_free_inodes_set(sb, gdp, count);
 268                         if (is_directory) {
 269                                 count = ext4_used_dirs_count(sb, gdp) - 1;
 270                                 ext4_used_dirs_set(sb, gdp, count);
 271                         }
 272                         gdp->bg_checksum = ext4_group_desc_csum(sbi,
 273                                                         block_group, gdp);
 274                         spin_unlock(sb_bgl_lock(sbi, block_group));
 275                         percpu_counter_inc(&sbi->s_freeinodes_counter);
 276                         if (is_directory)
 277                                 percpu_counter_dec(&sbi->s_dirs_counter);
 278
 279                         if (sbi->s_log_groups_per_flex) {
 280                                 flex_group = ext4_flex_group(sbi, block_group);
 281                                 spin_lock(sb_bgl_lock(sbi, flex_group));
 282                                 sbi->s_flex_groups[flex_group].free_inodes++;
 283                                 spin_unlock(sb_bgl_lock(sbi, flex_group));
 284                         }
 285                 }
 286                 BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 287                 err = ext4_handle_dirty_metadata(handle, NULL, bh2);
 288                 if (!fatal) fatal = err;
 289         }
 290         BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 291         err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 292         if (!fatal)
 293                 fatal = err;
 294         sb->s_dirt = 1;
 295 error_return:
 296         brelse(bitmap_bh);
 297         ext4_std_error(sb, fatal);
 298 }
 299
 300 /*
 301  * There are two policies for allocating an inode.  If the new inode is
 302  * a directory, then a forward search is made for a block group with both
 303  * free space and a low directory-to-inode ratio; if that fails, then of
 304  * the groups with above-average free space, that group with the fewest
 305  * directories already is chosen.
 306  *
 307  * For other inodes, search forward from the parent directory\'s block
 308  * group to find a free inode.
 309  */
 310 static int find_group_dir(struct super_block *sb, struct inode *parent,
 311                                 ext4_group_t *best_group)
 312 {
 313         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 314         unsigned int freei, avefreei;
 315         struct ext4_group_desc *desc, *best_desc = NULL;
 316         ext4_group_t group;
 317         int ret = -1;
 318
 319         freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
 320         avefreei = freei / ngroups;
 321
 322         for (group = 0; group < ngroups; group++) {
 323                 desc = ext4_get_group_desc(sb, group, NULL);
 324                 if (!desc || !ext4_free_inodes_count(sb, desc))
 325                         continue;
 326                 if (ext4_free_inodes_count(sb, desc) < avefreei)
 327                         continue;
 328                 if (!best_desc ||
 329                     (ext4_free_blks_count(sb, desc) >
 330                      ext4_free_blks_count(sb, best_desc))) {
 331                         *best_group = group;
 332                         best_desc = desc;
 333                         ret = 0;
 334                 }
 335         }
 336         return ret;
 337 }
 338
 339 #define free_block_ratio 10
 340
 341 static int find_group_flex(struct super_block *sb, struct inode *parent,
 342                            ext4_group_t *best_group)
 343 {
 344         struct ext4_sb_info *sbi = EXT4_SB(sb);
 345         struct ext4_group_desc *desc;
 346         struct buffer_head *bh;
 347         struct flex_groups *flex_group = sbi->s_flex_groups;
 348         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 349         ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
 350         ext4_group_t ngroups = sbi->s_groups_count;
 351         int flex_size = ext4_flex_bg_size(sbi);
 352         ext4_group_t best_flex = parent_fbg_group;
 353         int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
 354         int flexbg_free_blocks;
 355         int flex_freeb_ratio;
 356         ext4_group_t n_fbg_groups;
 357         ext4_group_t i;
 358
 359         n_fbg_groups = (sbi->s_groups_count + flex_size - 1) >>
 360                 sbi->s_log_groups_per_flex;
 361
 362 find_close_to_parent:
 363         flexbg_free_blocks = flex_group[best_flex].free_blocks;
 364         flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 365         if (flex_group[best_flex].free_inodes &&
 366             flex_freeb_ratio > free_block_ratio)
 367                 goto found_flexbg;
 368
 369         if (best_flex && best_flex == parent_fbg_group) {
 370                 best_flex--;
 371                 goto find_close_to_parent;
 372         }
 373
 374         for (i = 0; i < n_fbg_groups; i++) {
 375                 if (i == parent_fbg_group || i == parent_fbg_group - 1)
 376                         continue;
 377
 378                 flexbg_free_blocks = flex_group[i].free_blocks;
 379                 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 380
 381                 if (flex_freeb_ratio > free_block_ratio &&
 382                     flex_group[i].free_inodes) {
 383                         best_flex = i;
 384                         goto found_flexbg;
 385                 }
 386
 387                 if (flex_group[best_flex].free_inodes == 0 ||
 388                     (flex_group[i].free_blocks >
 389                      flex_group[best_flex].free_blocks &&
 390                      flex_group[i].free_inodes))
 391                         best_flex = i;
 392         }
 393
 394         if (!flex_group[best_flex].free_inodes ||
 395             !flex_group[best_flex].free_blocks)
 396                 return -1;
 397
 398 found_flexbg:
 399         for (i = best_flex * flex_size; i < ngroups &&
 400                      i < (best_flex + 1) * flex_size; i++) {
 401                 desc = ext4_get_group_desc(sb, i, &bh);
 402                 if (ext4_free_inodes_count(sb, desc)) {
 403                         *best_group = i;
 404                         goto out;
 405                 }
 406         }
 407
 408         return -1;
 409 out:
 410         return 0;
 411 }
 412
 413 /*
 414  * Orlov's allocator for directories.
 415  *
 416  * We always try to spread first-level directories.
 417  *
 418  * If there are blockgroups with both free inodes and free blocks counts
 419  * not worse than average we return one with smallest directory count.
 420  * Otherwise we simply return a random group.
 421  *
 422  * For the rest rules look so:
 423  *
 424  * It's OK to put directory into a group unless
 425  * it has too many directories already (max_dirs) or
 426  * it has too few free inodes left (min_inodes) or
 427  * it has too few free blocks left (min_blocks) or
 428  * it's already running too large debt (max_debt).
 429  * Parent's group is preferred, if it doesn't satisfy these
 430  * conditions we search cyclically through the rest. If none
 431  * of the groups look good we just look for a group with more
 432  * free inodes than average (starting at parent's group).
 433  *
 434  * Debt is incremented each time we allocate a directory and decremented
 435  * when we allocate an inode, within 0--255.
 436  */
 437
 438 #define INODE_COST 64
 439 #define BLOCK_COST 256
 440
 441 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 442                                 ext4_group_t *group)
 443 {
 444         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 445         struct ext4_sb_info *sbi = EXT4_SB(sb);
 446         struct ext4_super_block *es = sbi->s_es;
 447         ext4_group_t ngroups = sbi->s_groups_count;
 448         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 449         unsigned int freei, avefreei;
 450         ext4_fsblk_t freeb, avefreeb;
 451         ext4_fsblk_t blocks_per_dir;
 452         unsigned int ndirs;
 453         int max_debt, max_dirs, min_inodes;
 454         ext4_grpblk_t min_blocks;
 455         ext4_group_t i;
 456         struct ext4_group_desc *desc;
 457
 458         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 459         avefreei = freei / ngroups;
 460         freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 461         avefreeb = freeb;
 462         do_div(avefreeb, ngroups);
 463         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 464
 465         if ((parent == sb->s_root->d_inode) ||
 466             (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
 467                 int best_ndir = inodes_per_group;
 468                 ext4_group_t grp;
 469                 int ret = -1;
 470
 471                 get_random_bytes(&grp, sizeof(grp));
 472                 parent_group = (unsigned)grp % ngroups;
 473                 for (i = 0; i < ngroups; i++) {
 474                         grp = (parent_group + i) % ngroups;
 475                         desc = ext4_get_group_desc(sb, grp, NULL);
 476                         if (!desc || !ext4_free_inodes_count(sb, desc))
 477                                 continue;
 478                         if (ext4_used_dirs_count(sb, desc) >= best_ndir)
 479                                 continue;
 480                         if (ext4_free_inodes_count(sb, desc) < avefreei)
 481                                 continue;
 482                         if (ext4_free_blks_count(sb, desc) < avefreeb)
 483                                 continue;
 484                         *group = grp;
 485                         ret = 0;
 486                         best_ndir = ext4_used_dirs_count(sb, desc);
 487                 }
 488                 if (ret == 0)
 489                         return ret;
 490                 goto fallback;
 491         }
 492
 493         blocks_per_dir = ext4_blocks_count(es) - freeb;
 494         do_div(blocks_per_dir, ndirs);
 495
 496         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 497         min_inodes = avefreei - inodes_per_group / 4;
 498         min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb) / 4;
 499
 500         max_debt = EXT4_BLOCKS_PER_GROUP(sb);
 501         max_debt /= max_t(int, blocks_per_dir, BLOCK_COST);
 502         if (max_debt * INODE_COST > inodes_per_group)
 503                 max_debt = inodes_per_group / INODE_COST;
 504         if (max_debt > 255)
 505                 max_debt = 255;
 506         if (max_debt == 0)
 507                 max_debt = 1;
 508
 509         for (i = 0; i < ngroups; i++) {
 510                 *group = (parent_group + i) % ngroups;
 511                 desc = ext4_get_group_desc(sb, *group, NULL);
 512                 if (!desc || !ext4_free_inodes_count(sb, desc))
 513                         continue;
 514                 if (ext4_used_dirs_count(sb, desc) >= max_dirs)
 515                         continue;
 516                 if (ext4_free_inodes_count(sb, desc) < min_inodes)
 517                         continue;
 518                 if (ext4_free_blks_count(sb, desc) < min_blocks)
 519                         continue;
 520                 return 0;
 521         }
 522
 523 fallback:
 524         for (i = 0; i < ngroups; i++) {
 525                 *group = (parent_group + i) % ngroups;
 526                 desc = ext4_get_group_desc(sb, *group, NULL);
 527                 if (desc && ext4_free_inodes_count(sb, desc) &&
 528                         ext4_free_inodes_count(sb, desc) >= avefreei)
 529                         return 0;
 530         }
 531
 532         if (avefreei) {
 533                 /*
 534                  * The free-inodes counter is approximate, and for really small
 535                  * filesystems the above test can fail to find any blockgroups
 536                  */
 537                 avefreei = 0;
 538                 goto fallback;
 539         }
 540
 541         return -1;
 542 }
 543
 544 static int find_group_other(struct super_block *sb, struct inode *parent,
 545                                 ext4_group_t *group)
 546 {
 547         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 548         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 549         struct ext4_group_desc *desc;
 550         ext4_group_t i;
 551
 552         /*
 553          * Try to place the inode in its parent directory
 554          */
 555         *group = parent_group;
 556         desc = ext4_get_group_desc(sb, *group, NULL);
 557         if (desc && ext4_free_inodes_count(sb, desc) &&
 558                         ext4_free_blks_count(sb, desc))
 559                 return 0;
 560
 561         /*
 562          * We're going to place this inode in a different blockgroup from its
 563          * parent.  We want to cause files in a common directory to all land in
 564          * the same blockgroup.  But we want files which are in a different
 565          * directory which shares a blockgroup with our parent to land in a
 566          * different blockgroup.
 567          *
 568          * So add our directory's i_ino into the starting point for the hash.
 569          */
 570         *group = (*group + parent->i_ino) % ngroups;
 571
 572         /*
 573          * Use a quadratic hash to find a group with a free inode and some free
 574          * blocks.
 575          */
 576         for (i = 1; i < ngroups; i <<= 1) {
 577                 *group += i;
 578                 if (*group >= ngroups)
 579                         *group -= ngroups;
 580                 desc = ext4_get_group_desc(sb, *group, NULL);
 581                 if (desc && ext4_free_inodes_count(sb, desc) &&
 582                                 ext4_free_blks_count(sb, desc))
 583                         return 0;
 584         }
 585
 586         /*
 587          * That failed: try linear search for a free inode, even if that group
 588          * has no free blocks.
 589          */
 590         *group = parent_group;
 591         for (i = 0; i < ngroups; i++) {
 592                 if (++*group >= ngroups)
 593                         *group = 0;
 594                 desc = ext4_get_group_desc(sb, *group, NULL);
 595                 if (desc && ext4_free_inodes_count(sb, desc))
 596                         return 0;
 597         }
 598
 599         return -1;
 600 }
 601
 602 /*
 603  * claim the inode from the inode bitmap. If the group
 604  * is uninit we need to take the groups's sb_bgl_lock
 605  * and clear the uninit flag. The inode bitmap update
 606  * and group desc uninit flag clear should be done
 607  * after holding sb_bgl_lock so that ext4_read_inode_bitmap
 608  * doesn't race with the ext4_claim_inode
 609  */
 610 static int ext4_claim_inode(struct super_block *sb,
 611                         struct buffer_head *inode_bitmap_bh,
 612                         unsigned long ino, ext4_group_t group, int mode)
 613 {
 614         int free = 0, retval = 0, count;
 615         struct ext4_sb_info *sbi = EXT4_SB(sb);
 616         struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
 617
 618         spin_lock(sb_bgl_lock(sbi, group));
 619         if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
 620                 /* not a free inode */
 621                 retval = 1;
 622                 goto err_ret;
 623         }
 624         ino++;
 625         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
 626                         ino > EXT4_INODES_PER_GROUP(sb)) {
 627                 spin_unlock(sb_bgl_lock(sbi, group));
 628                 ext4_error(sb, __func__,
 629                            "reserved inode or inode > inodes count - "
 630                            "block_group = %u, inode=%lu", group,
 631                            ino + group * EXT4_INODES_PER_GROUP(sb));
 632                 return 1;
 633         }
 634         /* If we didn't allocate from within the initialized part of the inode
 635          * table then we need to initialize up to this inode. */
 636         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 637
 638                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 639                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 640                         /* When marking the block group with
 641                          * ~EXT4_BG_INODE_UNINIT we don't want to depend
 642                          * on the value of bg_itable_unused even though
 643                          * mke2fs could have initialized the same for us.
 644                          * Instead we calculated the value below
 645                          */
 646
 647                         free = 0;
 648                 } else {
 649                         free = EXT4_INODES_PER_GROUP(sb) -
 650                                 ext4_itable_unused_count(sb, gdp);
 651                 }
 652
 653                 /*
 654                  * Check the relative inode number against the last used
 655                  * relative inode number in this group. if it is greater
 656                  * we need to  update the bg_itable_unused count
 657                  *
 658                  */
 659                 if (ino > free)
 660                         ext4_itable_unused_set(sb, gdp,
 661                                         (EXT4_INODES_PER_GROUP(sb) - ino));
 662         }
 663         count = ext4_free_inodes_count(sb, gdp) - 1;
 664         ext4_free_inodes_set(sb, gdp, count);
 665         if (S_ISDIR(mode)) {
 666                 count = ext4_used_dirs_count(sb, gdp) + 1;
 667                 ext4_used_dirs_set(sb, gdp, count);
 668         }
 669         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
 670 err_ret:
 671         spin_unlock(sb_bgl_lock(sbi, group));
 672         return retval;
 673 }
 674
 675 /*
 676  * There are two policies for allocating an inode.  If the new inode is
 677  * a directory, then a forward search is made for a block group with both
 678  * free space and a low directory-to-inode ratio; if that fails, then of
 679  * the groups with above-average free space, that group with the fewest
 680  * directories already is chosen.
 681  *
 682  * For other inodes, search forward from the parent directory's block
 683  * group to find a free inode.
 684  */
 685 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
 686 {
 687         struct super_block *sb;
 688         struct buffer_head *inode_bitmap_bh = NULL;
 689         struct buffer_head *group_desc_bh;
 690         ext4_group_t group = 0;
 691         unsigned long ino = 0;
 692         struct inode *inode;
 693         struct ext4_group_desc *gdp = NULL;
 694         struct ext4_super_block *es;
 695         struct ext4_inode_info *ei;
 696         struct ext4_sb_info *sbi;
 697         int ret2, err = 0;
 698         struct inode *ret;
 699         ext4_group_t i;
 700         int free = 0;
 701         static int once = 1;
 702         ext4_group_t flex_group;
 703
 704         /* Cannot create files in a deleted directory */
 705         if (!dir || !dir->i_nlink)
 706                 return ERR_PTR(-EPERM);
 707
 708         sb = dir->i_sb;
 709         trace_mark(ext4_request_inode, "dev %s dir %lu mode %d", sb->s_id,
 710                    dir->i_ino, mode);
 711         inode = new_inode(sb);
 712         if (!inode)
 713                 return ERR_PTR(-ENOMEM);
 714         ei = EXT4_I(inode);
 715
 716         sbi = EXT4_SB(sb);
 717         es = sbi->s_es;
 718
 719         if (sbi->s_log_groups_per_flex) {
 720                 ret2 = find_group_flex(sb, dir, &group);
 721                 if (ret2 == -1) {
 722                         ret2 = find_group_other(sb, dir, &group);
 723                         if (ret2 == 0 && once)
 724                                 once = 0;
 725                                 printk(KERN_NOTICE "ext4: find_group_flex "
 726                                        "failed, fallback succeeded dir %lu\n",
 727                                        dir->i_ino);
 728                 }
 729                 goto got_group;
 730         }
 731
 732         if (S_ISDIR(mode)) {
 733                 if (test_opt(sb, OLDALLOC))
 734                         ret2 = find_group_dir(sb, dir, &group);
 735                 else
 736                         ret2 = find_group_orlov(sb, dir, &group);
 737         } else
 738                 ret2 = find_group_other(sb, dir, &group);
 739
 740 got_group:
 741         err = -ENOSPC;
 742         if (ret2 == -1)
 743                 goto out;
 744
 745         for (i = 0; i < sbi->s_groups_count; i++) {
 746                 err = -EIO;
 747
 748                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 749                 if (!gdp)
 750                         goto fail;
 751
 752                 brelse(inode_bitmap_bh);
 753                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 754                 if (!inode_bitmap_bh)
 755                         goto fail;
 756
 757                 ino = 0;
 758
 759 repeat_in_this_group:
 760                 ino = ext4_find_next_zero_bit((unsigned long *)
 761                                               inode_bitmap_bh->b_data,
 762                                               EXT4_INODES_PER_GROUP(sb), ino);
 763
 764                 if (ino < EXT4_INODES_PER_GROUP(sb)) {
 765
 766                         BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 767                         err = ext4_journal_get_write_access(handle,
 768                                                             inode_bitmap_bh);
 769                         if (err)
 770                                 goto fail;
 771
 772                         BUFFER_TRACE(group_desc_bh, "get_write_access");
 773                         err = ext4_journal_get_write_access(handle,
 774                                                                 group_desc_bh);
 775                         if (err)
 776                                 goto fail;
 777                         if (!ext4_claim_inode(sb, inode_bitmap_bh,
 778                                                 ino, group, mode)) {
 779                                 /* we won it */
 780                                 BUFFER_TRACE(inode_bitmap_bh,
 781                                         "call ext4_handle_dirty_metadata");
 782                                 err = ext4_handle_dirty_metadata(handle,
 783                                                                  inode,
 784                                                         inode_bitmap_bh);
 785                                 if (err)
 786                                         goto fail;
 787                                 /* zero bit is inode number 1*/
 788                                 ino++;
 789                                 goto got;
 790                         }
 791                         /* we lost it */
 792                         ext4_handle_release_buffer(handle, inode_bitmap_bh);
 793                         ext4_handle_release_buffer(handle, group_desc_bh);
 794
 795                         if (++ino < EXT4_INODES_PER_GROUP(sb))
 796                                 goto repeat_in_this_group;
 797                 }
 798
 799                 /*
 800                  * This case is possible in concurrent environment.  It is very
 801                  * rare.  We cannot repeat the find_group_xxx() call because
 802                  * that will simply return the same blockgroup, because the
 803                  * group descriptor metadata has not yet been updated.
 804                  * So we just go onto the next blockgroup.
 805                  */
 806                 if (++group == sbi->s_groups_count)
 807                         group = 0;
 808         }
 809         err = -ENOSPC;
 810         goto out;
 811
 812 got:
 813         /* We may have to initialize the block bitmap if it isn't already */
 814         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
 815             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 816                 struct buffer_head *block_bitmap_bh;
 817
 818                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 819                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 820                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 821                 if (err) {
 822                         brelse(block_bitmap_bh);
 823                         goto fail;
 824                 }
 825
 826                 free = 0;
 827                 spin_lock(sb_bgl_lock(sbi, group));
 828                 /* recheck and clear flag under lock if we still need to */
 829                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 830                         free = ext4_free_blocks_after_init(sb, group, gdp);
 831                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 832                         ext4_free_blks_set(sb, gdp, free);
 833                         gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
 834                                                                 gdp);
 835                 }
 836                 spin_unlock(sb_bgl_lock(sbi, group));
 837
 838                 /* Don't need to dirty bitmap block if we didn't change it */
 839                 if (free) {
 840                         BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
 841                         err = ext4_handle_dirty_metadata(handle,
 842                                                         NULL, block_bitmap_bh);
 843                 }
 844
 845                 brelse(block_bitmap_bh);
 846                 if (err)
 847                         goto fail;
 848         }
 849         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
 850         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
 851         if (err)
 852                 goto fail;
 853
 854         percpu_counter_dec(&sbi->s_freeinodes_counter);
 855         if (S_ISDIR(mode))
 856                 percpu_counter_inc(&sbi->s_dirs_counter);
 857         sb->s_dirt = 1;
 858
 859         if (sbi->s_log_groups_per_flex) {
 860                 flex_group = ext4_flex_group(sbi, group);
 861                 spin_lock(sb_bgl_lock(sbi, flex_group));
 862                 sbi->s_flex_groups[flex_group].free_inodes--;
 863                 spin_unlock(sb_bgl_lock(sbi, flex_group));
 864         }
 865
 866         inode->i_uid = current_fsuid();
 867         if (test_opt(sb, GRPID))
 868                 inode->i_gid = dir->i_gid;
 869         else if (dir->i_mode & S_ISGID) {
 870                 inode->i_gid = dir->i_gid;
 871                 if (S_ISDIR(mode))
 872                         mode |= S_ISGID;
 873         } else
 874                 inode->i_gid = current_fsgid();
 875         inode->i_mode = mode;
 876
 877         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
 878         /* This is the optimal IO size (for stat), not the fs block size */
 879         inode->i_blocks = 0;
 880         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
 881                                                        ext4_current_time(inode);
 882
 883         memset(ei->i_data, 0, sizeof(ei->i_data));
 884         ei->i_dir_start_lookup = 0;
 885         ei->i_disksize = 0;
 886
 887         /*
 888          * Don't inherit extent flag from directory. We set extent flag on
 889          * newly created directory and file only if -o extent mount option is
 890          * specified
 891          */
 892         ei->i_flags = EXT4_I(dir)->i_flags & ~(EXT4_INDEX_FL|EXT4_EXTENTS_FL);
 893         if (S_ISLNK(mode))
 894                 ei->i_flags &= ~(EXT4_IMMUTABLE_FL|EXT4_APPEND_FL);
 895         /* dirsync only applies to directories */
 896         if (!S_ISDIR(mode))
 897                 ei->i_flags &= ~EXT4_DIRSYNC_FL;
 898         ei->i_file_acl = 0;
 899         ei->i_dtime = 0;
 900         ei->i_block_group = group;
 901
 902         ext4_set_inode_flags(inode);
 903         if (IS_DIRSYNC(inode))
 904                 ext4_handle_sync(handle);
 905         if (insert_inode_locked(inode) < 0) {
 906                 err = -EINVAL;
 907                 goto fail_drop;
 908         }
 909         spin_lock(&sbi->s_next_gen_lock);
 910         inode->i_generation = sbi->s_next_generation++;
 911         spin_unlock(&sbi->s_next_gen_lock);
 912
 913         ei->i_state = EXT4_STATE_NEW;
 914
 915         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
 916
 917         ret = inode;
 918         if (DQUOT_ALLOC_INODE(inode)) {
 919                 err = -EDQUOT;
 920                 goto fail_drop;
 921         }
 922
 923         err = ext4_init_acl(handle, inode, dir);
 924         if (err)
 925                 goto fail_free_drop;
 926
 927         err = ext4_init_security(handle, inode, dir);
 928         if (err)
 929                 goto fail_free_drop;
 930
 931         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
 932                 /* set extent flag only for directory, file and normal symlink*/
 933                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
 934                         EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;
 935                         ext4_ext_tree_init(handle, inode);
 936                 }
 937         }
 938
 939         err = ext4_mark_inode_dirty(handle, inode);
 940         if (err) {
 941                 ext4_std_error(sb, err);
 942                 goto fail_free_drop;
 943         }
 944
 945         ext4_debug("allocating inode %lu\n", inode->i_ino);
 946         trace_mark(ext4_allocate_inode, "dev %s ino %lu dir %lu mode %d",
 947                    sb->s_id, inode->i_ino, dir->i_ino, mode);
 948         goto really_out;
 949 fail:
 950         ext4_std_error(sb, err);
 951 out:
 952         iput(inode);
 953         ret = ERR_PTR(err);
 954 really_out:
 955         brelse(inode_bitmap_bh);
 956         return ret;
 957
 958 fail_free_drop:
 959         DQUOT_FREE_INODE(inode);
 960
 961 fail_drop:
 962         DQUOT_DROP(inode);
 963         inode->i_flags |= S_NOQUOTA;
 964         inode->i_nlink = 0;
 965         unlock_new_inode(inode);
 966         iput(inode);
 967         brelse(inode_bitmap_bh);
 968         return ERR_PTR(err);
 969 }
 970
 971 /* Verify that we are loading a valid orphan from disk */
 972 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
 973 {
 974         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
 975         ext4_group_t block_group;
 976         int bit;
 977         struct buffer_head *bitmap_bh;
 978         struct inode *inode = NULL;
 979         long err = -EIO;
 980
 981         /* Error cases - e2fsck has already cleaned up for us */
 982         if (ino > max_ino) {
 983                 ext4_warning(sb, __func__,
 984                              "bad orphan ino %lu!  e2fsck was run?", ino);
 985                 goto error;
 986         }
 987
 988         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 989         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 990         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 991         if (!bitmap_bh) {
 992                 ext4_warning(sb, __func__,
 993                              "inode bitmap error for orphan %lu", ino);
 994                 goto error;
 995         }
 996
 997         /* Having the inode bit set should be a 100% indicator that this
 998          * is a valid orphan (no e2fsck run on fs).  Orphans also include
 999          * inodes that were being truncated, so we can't check i_nlink==0.
1000          */
1001         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1002                 goto bad_orphan;
1003
1004         inode = ext4_iget(sb, ino);
1005         if (IS_ERR(inode))
1006                 goto iget_failed;
1007
1008         /*
1009          * If the orphans has i_nlinks > 0 then it should be able to be
1010          * truncated, otherwise it won't be removed from the orphan list
1011          * during processing and an infinite loop will result.
1012          */
1013         if (inode->i_nlink && !ext4_can_truncate(inode))
1014                 goto bad_orphan;
1015
1016         if (NEXT_ORPHAN(inode) > max_ino)
1017                 goto bad_orphan;
1018         brelse(bitmap_bh);
1019         return inode;
1020
1021 iget_failed:
1022         err = PTR_ERR(inode);
1023         inode = NULL;
1024 bad_orphan:
1025         ext4_warning(sb, __func__,
1026                      "bad orphan inode %lu!  e2fsck was run?", ino);
1027         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1028                bit, (unsigned long long)bitmap_bh->b_blocknr,
1029                ext4_test_bit(bit, bitmap_bh->b_data));
1030         printk(KERN_NOTICE "inode=%p\n", inode);
1031         if (inode) {
1032                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
1033                        is_bad_inode(inode));
1034                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
1035                        NEXT_ORPHAN(inode));
1036                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
1037                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
1038                 /* Avoid freeing blocks if we got a bad deleted inode */
1039                 if (inode->i_nlink == 0)
1040                         inode->i_blocks = 0;
1041                 iput(inode);
1042         }
1043         brelse(bitmap_bh);
1044 error:
1045         return ERR_PTR(err);
1046 }
1047
1048 unsigned long ext4_count_free_inodes(struct super_block *sb)
1049 {
1050         unsigned long desc_count;
1051         struct ext4_group_desc *gdp;
1052         ext4_group_t i;
1053 #ifdef EXT4FS_DEBUG
1054         struct ext4_super_block *es;
1055         unsigned long bitmap_count, x;
1056         struct buffer_head *bitmap_bh = NULL;
1057
1058         es = EXT4_SB(sb)->s_es;
1059         desc_count = 0;
1060         bitmap_count = 0;
1061         gdp = NULL;
1062         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1063                 gdp = ext4_get_group_desc(sb, i, NULL);
1064                 if (!gdp)
1065                         continue;
1066                 desc_count += ext4_free_inodes_count(sb, gdp);
1067                 brelse(bitmap_bh);
1068                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1069                 if (!bitmap_bh)
1070                         continue;
1071
1072                 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
1073                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1074                         i, ext4_free_inodes_count(sb, gdp), x);
1075                 bitmap_count += x;
1076         }
1077         brelse(bitmap_bh);
1078         printk(KERN_DEBUG "ext4_count_free_inodes: "
1079                "stored = %u, computed = %lu, %lu\n",
1080                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1081         return desc_count;
1082 #else
1083         desc_count = 0;
1084         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1085                 gdp = ext4_get_group_desc(sb, i, NULL);
1086                 if (!gdp)
1087                         continue;
1088                 desc_count += ext4_free_inodes_count(sb, gdp);
1089                 cond_resched();
1090         }
1091         return desc_count;
1092 #endif
1093 }
1094
1095 /* Called at mount-time, super-block is locked */
1096 unsigned long ext4_count_dirs(struct super_block * sb)
1097 {
1098         unsigned long count = 0;
1099         ext4_group_t i;
1100
1101         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1102                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1103                 if (!gdp)
1104                         continue;
1105                 count += ext4_used_dirs_count(sb, gdp);
1106         }
1107         return count;
1108 }