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;
 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         if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
 252                                         bit, bitmap_bh->b_data))
 253                 ext4_error(sb, "ext4_free_inode",
 254                            "bit already cleared for inode %lu", ino);
 255         else {
 256                 gdp = ext4_get_group_desc(sb, block_group, &bh2);
 257
 258                 BUFFER_TRACE(bh2, "get_write_access");
 259                 fatal = ext4_journal_get_write_access(handle, bh2);
 260                 if (fatal) goto error_return;
 261
 262                 if (gdp) {
 263                         spin_lock(sb_bgl_lock(sbi, block_group));
 264                         count = ext4_free_inodes_count(sb, gdp) + 1;
 265                         ext4_free_inodes_set(sb, gdp, count);
 266                         if (is_directory) {
 267                                 count = ext4_used_dirs_count(sb, gdp) - 1;
 268                                 ext4_used_dirs_set(sb, gdp, count);
 269                         }
 270                         gdp->bg_checksum = ext4_group_desc_csum(sbi,
 271                                                         block_group, gdp);
 272                         spin_unlock(sb_bgl_lock(sbi, block_group));
 273                         percpu_counter_inc(&sbi->s_freeinodes_counter);
 274                         if (is_directory)
 275                                 percpu_counter_dec(&sbi->s_dirs_counter);
 276
 277                         if (sbi->s_log_groups_per_flex) {
 278                                 flex_group = ext4_flex_group(sbi, block_group);
 279                                 spin_lock(sb_bgl_lock(sbi, flex_group));
 280                                 sbi->s_flex_groups[flex_group].free_inodes++;
 281                                 spin_unlock(sb_bgl_lock(sbi, flex_group));
 282                         }
 283                 }
 284                 BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 285                 err = ext4_handle_dirty_metadata(handle, NULL, bh2);
 286                 if (!fatal) fatal = err;
 287         }
 288         BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 289         err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 290         if (!fatal)
 291                 fatal = err;
 292         sb->s_dirt = 1;
 293 error_return:
 294         brelse(bitmap_bh);
 295         ext4_std_error(sb, fatal);
 296 }
 297
 298 /*
 299  * There are two policies for allocating an inode.  If the new inode is
 300  * a directory, then a forward search is made for a block group with both
 301  * free space and a low directory-to-inode ratio; if that fails, then of
 302  * the groups with above-average free space, that group with the fewest
 303  * directories already is chosen.
 304  *
 305  * For other inodes, search forward from the parent directory\'s block
 306  * group to find a free inode.
 307  */
 308 static int find_group_dir(struct super_block *sb, struct inode *parent,
 309                                 ext4_group_t *best_group)
 310 {
 311         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 312         unsigned int freei, avefreei;
 313         struct ext4_group_desc *desc, *best_desc = NULL;
 314         ext4_group_t group;
 315         int ret = -1;
 316
 317         freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
 318         avefreei = freei / ngroups;
 319
 320         for (group = 0; group < ngroups; group++) {
 321                 desc = ext4_get_group_desc(sb, group, NULL);
 322                 if (!desc || !ext4_free_inodes_count(sb, desc))
 323                         continue;
 324                 if (ext4_free_inodes_count(sb, desc) < avefreei)
 325                         continue;
 326                 if (!best_desc ||
 327                     (ext4_free_blks_count(sb, desc) >
 328                      ext4_free_blks_count(sb, best_desc))) {
 329                         *best_group = group;
 330                         best_desc = desc;
 331                         ret = 0;
 332                 }
 333         }
 334         return ret;
 335 }
 336
 337 #define free_block_ratio 10
 338
 339 static int find_group_flex(struct super_block *sb, struct inode *parent,
 340                            ext4_group_t *best_group)
 341 {
 342         struct ext4_sb_info *sbi = EXT4_SB(sb);
 343         struct ext4_group_desc *desc;
 344         struct buffer_head *bh;
 345         struct flex_groups *flex_group = sbi->s_flex_groups;
 346         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 347         ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
 348         ext4_group_t ngroups = sbi->s_groups_count;
 349         int flex_size = ext4_flex_bg_size(sbi);
 350         ext4_group_t best_flex = parent_fbg_group;
 351         int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
 352         int flexbg_free_blocks;
 353         int flex_freeb_ratio;
 354         ext4_group_t n_fbg_groups;
 355         ext4_group_t i;
 356
 357         n_fbg_groups = (sbi->s_groups_count + flex_size - 1) >>
 358                 sbi->s_log_groups_per_flex;
 359
 360 find_close_to_parent:
 361         flexbg_free_blocks = flex_group[best_flex].free_blocks;
 362         flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 363         if (flex_group[best_flex].free_inodes &&
 364             flex_freeb_ratio > free_block_ratio)
 365                 goto found_flexbg;
 366
 367         if (best_flex && best_flex == parent_fbg_group) {
 368                 best_flex--;
 369                 goto find_close_to_parent;
 370         }
 371
 372         for (i = 0; i < n_fbg_groups; i++) {
 373                 if (i == parent_fbg_group || i == parent_fbg_group - 1)
 374                         continue;
 375
 376                 flexbg_free_blocks = flex_group[i].free_blocks;
 377                 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 378
 379                 if (flex_freeb_ratio > free_block_ratio &&
 380                     flex_group[i].free_inodes) {
 381                         best_flex = i;
 382                         goto found_flexbg;
 383                 }
 384
 385                 if (flex_group[best_flex].free_inodes == 0 ||
 386                     (flex_group[i].free_blocks >
 387                      flex_group[best_flex].free_blocks &&
 388                      flex_group[i].free_inodes))
 389                         best_flex = i;
 390         }
 391
 392         if (!flex_group[best_flex].free_inodes ||
 393             !flex_group[best_flex].free_blocks)
 394                 return -1;
 395
 396 found_flexbg:
 397         for (i = best_flex * flex_size; i < ngroups &&
 398                      i < (best_flex + 1) * flex_size; i++) {
 399                 desc = ext4_get_group_desc(sb, i, &bh);
 400                 if (ext4_free_inodes_count(sb, desc)) {
 401                         *best_group = i;
 402                         goto out;
 403                 }
 404         }
 405
 406         return -1;
 407 out:
 408         return 0;
 409 }
 410
 411 /*
 412  * Orlov's allocator for directories.
 413  *
 414  * We always try to spread first-level directories.
 415  *
 416  * If there are blockgroups with both free inodes and free blocks counts
 417  * not worse than average we return one with smallest directory count.
 418  * Otherwise we simply return a random group.
 419  *
 420  * For the rest rules look so:
 421  *
 422  * It's OK to put directory into a group unless
 423  * it has too many directories already (max_dirs) or
 424  * it has too few free inodes left (min_inodes) or
 425  * it has too few free blocks left (min_blocks) or
 426  * it's already running too large debt (max_debt).
 427  * Parent's group is preferred, if it doesn't satisfy these
 428  * conditions we search cyclically through the rest. If none
 429  * of the groups look good we just look for a group with more
 430  * free inodes than average (starting at parent's group).
 431  *
 432  * Debt is incremented each time we allocate a directory and decremented
 433  * when we allocate an inode, within 0--255.
 434  */
 435
 436 #define INODE_COST 64
 437 #define BLOCK_COST 256
 438
 439 static int find_group_orlov(struct super_block *sb, struct inode *parent,
 440                                 ext4_group_t *group)
 441 {
 442         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 443         struct ext4_sb_info *sbi = EXT4_SB(sb);
 444         struct ext4_super_block *es = sbi->s_es;
 445         ext4_group_t ngroups = sbi->s_groups_count;
 446         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 447         unsigned int freei, avefreei;
 448         ext4_fsblk_t freeb, avefreeb;
 449         ext4_fsblk_t blocks_per_dir;
 450         unsigned int ndirs;
 451         int max_debt, max_dirs, min_inodes;
 452         ext4_grpblk_t min_blocks;
 453         ext4_group_t i;
 454         struct ext4_group_desc *desc;
 455
 456         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 457         avefreei = freei / ngroups;
 458         freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 459         avefreeb = freeb;
 460         do_div(avefreeb, ngroups);
 461         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 462
 463         if ((parent == sb->s_root->d_inode) ||
 464             (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
 465                 int best_ndir = inodes_per_group;
 466                 ext4_group_t grp;
 467                 int ret = -1;
 468
 469                 get_random_bytes(&grp, sizeof(grp));
 470                 parent_group = (unsigned)grp % ngroups;
 471                 for (i = 0; i < ngroups; i++) {
 472                         grp = (parent_group + i) % ngroups;
 473                         desc = ext4_get_group_desc(sb, grp, NULL);
 474                         if (!desc || !ext4_free_inodes_count(sb, desc))
 475                                 continue;
 476                         if (ext4_used_dirs_count(sb, desc) >= best_ndir)
 477                                 continue;
 478                         if (ext4_free_inodes_count(sb, desc) < avefreei)
 479                                 continue;
 480                         if (ext4_free_blks_count(sb, desc) < avefreeb)
 481                                 continue;
 482                         *group = grp;
 483                         ret = 0;
 484                         best_ndir = ext4_used_dirs_count(sb, desc);
 485                 }
 486                 if (ret == 0)
 487                         return ret;
 488                 goto fallback;
 489         }
 490
 491         blocks_per_dir = ext4_blocks_count(es) - freeb;
 492         do_div(blocks_per_dir, ndirs);
 493
 494         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 495         min_inodes = avefreei - inodes_per_group / 4;
 496         min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb) / 4;
 497
 498         max_debt = EXT4_BLOCKS_PER_GROUP(sb);
 499         max_debt /= max_t(int, blocks_per_dir, BLOCK_COST);
 500         if (max_debt * INODE_COST > inodes_per_group)
 501                 max_debt = inodes_per_group / INODE_COST;
 502         if (max_debt > 255)
 503                 max_debt = 255;
 504         if (max_debt == 0)
 505                 max_debt = 1;
 506
 507         for (i = 0; i < ngroups; i++) {
 508                 *group = (parent_group + i) % ngroups;
 509                 desc = ext4_get_group_desc(sb, *group, NULL);
 510                 if (!desc || !ext4_free_inodes_count(sb, desc))
 511                         continue;
 512                 if (ext4_used_dirs_count(sb, desc) >= max_dirs)
 513                         continue;
 514                 if (ext4_free_inodes_count(sb, desc) < min_inodes)
 515                         continue;
 516                 if (ext4_free_blks_count(sb, desc) < min_blocks)
 517                         continue;
 518                 return 0;
 519         }
 520
 521 fallback:
 522         for (i = 0; i < ngroups; i++) {
 523                 *group = (parent_group + i) % ngroups;
 524                 desc = ext4_get_group_desc(sb, *group, NULL);
 525                 if (desc && ext4_free_inodes_count(sb, desc) &&
 526                         ext4_free_inodes_count(sb, desc) >= avefreei)
 527                         return 0;
 528         }
 529
 530         if (avefreei) {
 531                 /*
 532                  * The free-inodes counter is approximate, and for really small
 533                  * filesystems the above test can fail to find any blockgroups
 534                  */
 535                 avefreei = 0;
 536                 goto fallback;
 537         }
 538
 539         return -1;
 540 }
 541
 542 static int find_group_other(struct super_block *sb, struct inode *parent,
 543                                 ext4_group_t *group)
 544 {
 545         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 546         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
 547         struct ext4_group_desc *desc;
 548         ext4_group_t i;
 549
 550         /*
 551          * Try to place the inode in its parent directory
 552          */
 553         *group = parent_group;
 554         desc = ext4_get_group_desc(sb, *group, NULL);
 555         if (desc && ext4_free_inodes_count(sb, desc) &&
 556                         ext4_free_blks_count(sb, desc))
 557                 return 0;
 558
 559         /*
 560          * We're going to place this inode in a different blockgroup from its
 561          * parent.  We want to cause files in a common directory to all land in
 562          * the same blockgroup.  But we want files which are in a different
 563          * directory which shares a blockgroup with our parent to land in a
 564          * different blockgroup.
 565          *
 566          * So add our directory's i_ino into the starting point for the hash.
 567          */
 568         *group = (*group + parent->i_ino) % ngroups;
 569
 570         /*
 571          * Use a quadratic hash to find a group with a free inode and some free
 572          * blocks.
 573          */
 574         for (i = 1; i < ngroups; i <<= 1) {
 575                 *group += i;
 576                 if (*group >= ngroups)
 577                         *group -= ngroups;
 578                 desc = ext4_get_group_desc(sb, *group, NULL);
 579                 if (desc && ext4_free_inodes_count(sb, desc) &&
 580                                 ext4_free_blks_count(sb, desc))
 581                         return 0;
 582         }
 583
 584         /*
 585          * That failed: try linear search for a free inode, even if that group
 586          * has no free blocks.
 587          */
 588         *group = parent_group;
 589         for (i = 0; i < ngroups; i++) {
 590                 if (++*group >= ngroups)
 591                         *group = 0;
 592                 desc = ext4_get_group_desc(sb, *group, NULL);
 593                 if (desc && ext4_free_inodes_count(sb, desc))
 594                         return 0;
 595         }
 596
 597         return -1;
 598 }
 599
 600 /*
 601  * claim the inode from the inode bitmap. If the group
 602  * is uninit we need to take the groups's sb_bgl_lock
 603  * and clear the uninit flag. The inode bitmap update
 604  * and group desc uninit flag clear should be done
 605  * after holding sb_bgl_lock so that ext4_read_inode_bitmap
 606  * doesn't race with the ext4_claim_inode
 607  */
 608 static int ext4_claim_inode(struct super_block *sb,
 609                         struct buffer_head *inode_bitmap_bh,
 610                         unsigned long ino, ext4_group_t group, int mode)
 611 {
 612         int free = 0, retval = 0, count;
 613         struct ext4_sb_info *sbi = EXT4_SB(sb);
 614         struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
 615
 616         spin_lock(sb_bgl_lock(sbi, group));
 617         if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
 618                 /* not a free inode */
 619                 retval = 1;
 620                 goto err_ret;
 621         }
 622         ino++;
 623         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
 624                         ino > EXT4_INODES_PER_GROUP(sb)) {
 625                 spin_unlock(sb_bgl_lock(sbi, group));
 626                 ext4_error(sb, __func__,
 627                            "reserved inode or inode > inodes count - "
 628                            "block_group = %u, inode=%lu", group,
 629                            ino + group * EXT4_INODES_PER_GROUP(sb));
 630                 return 1;
 631         }
 632         /* If we didn't allocate from within the initialized part of the inode
 633          * table then we need to initialize up to this inode. */
 634         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 635
 636                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 637                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
 638                         /* When marking the block group with
 639                          * ~EXT4_BG_INODE_UNINIT we don't want to depend
 640                          * on the value of bg_itable_unused even though
 641                          * mke2fs could have initialized the same for us.
 642                          * Instead we calculated the value below
 643                          */
 644
 645                         free = 0;
 646                 } else {
 647                         free = EXT4_INODES_PER_GROUP(sb) -
 648                                 ext4_itable_unused_count(sb, gdp);
 649                 }
 650
 651                 /*
 652                  * Check the relative inode number against the last used
 653                  * relative inode number in this group. if it is greater
 654                  * we need to  update the bg_itable_unused count
 655                  *
 656                  */
 657                 if (ino > free)
 658                         ext4_itable_unused_set(sb, gdp,
 659                                         (EXT4_INODES_PER_GROUP(sb) - ino));
 660         }
 661         count = ext4_free_inodes_count(sb, gdp) - 1;
 662         ext4_free_inodes_set(sb, gdp, count);
 663         if (S_ISDIR(mode)) {
 664                 count = ext4_used_dirs_count(sb, gdp) + 1;
 665                 ext4_used_dirs_set(sb, gdp, count);
 666         }
 667         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
 668 err_ret:
 669         spin_unlock(sb_bgl_lock(sbi, group));
 670         return retval;
 671 }
 672
 673 /*
 674  * There are two policies for allocating an inode.  If the new inode is
 675  * a directory, then a forward search is made for a block group with both
 676  * free space and a low directory-to-inode ratio; if that fails, then of
 677  * the groups with above-average free space, that group with the fewest
 678  * directories already is chosen.
 679  *
 680  * For other inodes, search forward from the parent directory's block
 681  * group to find a free inode.
 682  */
 683 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
 684 {
 685         struct super_block *sb;
 686         struct buffer_head *inode_bitmap_bh = NULL;
 687         struct buffer_head *group_desc_bh;
 688         ext4_group_t group = 0;
 689         unsigned long ino = 0;
 690         struct inode *inode;
 691         struct ext4_group_desc *gdp = NULL;
 692         struct ext4_super_block *es;
 693         struct ext4_inode_info *ei;
 694         struct ext4_sb_info *sbi;
 695         int ret2, err = 0;
 696         struct inode *ret;
 697         ext4_group_t i;
 698         int free = 0;
 699         ext4_group_t flex_group;
 700
 701         /* Cannot create files in a deleted directory */
 702         if (!dir || !dir->i_nlink)
 703                 return ERR_PTR(-EPERM);
 704
 705         sb = dir->i_sb;
 706         trace_mark(ext4_request_inode, "dev %s dir %lu mode %d", sb->s_id,
 707                    dir->i_ino, mode);
 708         inode = new_inode(sb);
 709         if (!inode)
 710                 return ERR_PTR(-ENOMEM);
 711         ei = EXT4_I(inode);
 712
 713         sbi = EXT4_SB(sb);
 714         es = sbi->s_es;
 715
 716         if (sbi->s_log_groups_per_flex) {
 717                 ret2 = find_group_flex(sb, dir, &group);
 718                 goto got_group;
 719         }
 720
 721         if (S_ISDIR(mode)) {
 722                 if (test_opt(sb, OLDALLOC))
 723                         ret2 = find_group_dir(sb, dir, &group);
 724                 else
 725                         ret2 = find_group_orlov(sb, dir, &group);
 726         } else
 727                 ret2 = find_group_other(sb, dir, &group);
 728
 729 got_group:
 730         err = -ENOSPC;
 731         if (ret2 == -1)
 732                 goto out;
 733
 734         for (i = 0; i < sbi->s_groups_count; i++) {
 735                 err = -EIO;
 736
 737                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 738                 if (!gdp)
 739                         goto fail;
 740
 741                 brelse(inode_bitmap_bh);
 742                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 743                 if (!inode_bitmap_bh)
 744                         goto fail;
 745
 746                 ino = 0;
 747
 748 repeat_in_this_group:
 749                 ino = ext4_find_next_zero_bit((unsigned long *)
 750                                               inode_bitmap_bh->b_data,
 751                                               EXT4_INODES_PER_GROUP(sb), ino);
 752
 753                 if (ino < EXT4_INODES_PER_GROUP(sb)) {
 754
 755                         BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 756                         err = ext4_journal_get_write_access(handle,
 757                                                             inode_bitmap_bh);
 758                         if (err)
 759                                 goto fail;
 760
 761                         BUFFER_TRACE(group_desc_bh, "get_write_access");
 762                         err = ext4_journal_get_write_access(handle,
 763                                                                 group_desc_bh);
 764                         if (err)
 765                                 goto fail;
 766                         if (!ext4_claim_inode(sb, inode_bitmap_bh,
 767                                                 ino, group, mode)) {
 768                                 /* we won it */
 769                                 BUFFER_TRACE(inode_bitmap_bh,
 770                                         "call ext4_handle_dirty_metadata");
 771                                 err = ext4_handle_dirty_metadata(handle,
 772                                                                  inode,
 773                                                         inode_bitmap_bh);
 774                                 if (err)
 775                                         goto fail;
 776                                 /* zero bit is inode number 1*/
 777                                 ino++;
 778                                 goto got;
 779                         }
 780                         /* we lost it */
 781                         ext4_handle_release_buffer(handle, inode_bitmap_bh);
 782                         ext4_handle_release_buffer(handle, group_desc_bh);
 783
 784                         if (++ino < EXT4_INODES_PER_GROUP(sb))
 785                                 goto repeat_in_this_group;
 786                 }
 787
 788                 /*
 789                  * This case is possible in concurrent environment.  It is very
 790                  * rare.  We cannot repeat the find_group_xxx() call because
 791                  * that will simply return the same blockgroup, because the
 792                  * group descriptor metadata has not yet been updated.
 793                  * So we just go onto the next blockgroup.
 794                  */
 795                 if (++group == sbi->s_groups_count)
 796                         group = 0;
 797         }
 798         err = -ENOSPC;
 799         goto out;
 800
 801 got:
 802         /* We may have to initialize the block bitmap if it isn't already */
 803         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
 804             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 805                 struct buffer_head *block_bitmap_bh;
 806
 807                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 808                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 809                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 810                 if (err) {
 811                         brelse(block_bitmap_bh);
 812                         goto fail;
 813                 }
 814
 815                 free = 0;
 816                 spin_lock(sb_bgl_lock(sbi, group));
 817                 /* recheck and clear flag under lock if we still need to */
 818                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 819                         free = ext4_free_blocks_after_init(sb, group, gdp);
 820                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 821                         ext4_free_blks_set(sb, gdp, free);
 822                         gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
 823                                                                 gdp);
 824                 }
 825                 spin_unlock(sb_bgl_lock(sbi, group));
 826
 827                 /* Don't need to dirty bitmap block if we didn't change it */
 828                 if (free) {
 829                         BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
 830                         err = ext4_handle_dirty_metadata(handle,
 831                                                         NULL, block_bitmap_bh);
 832                 }
 833
 834                 brelse(block_bitmap_bh);
 835                 if (err)
 836                         goto fail;
 837         }
 838         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
 839         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
 840         if (err)
 841                 goto fail;
 842
 843         percpu_counter_dec(&sbi->s_freeinodes_counter);
 844         if (S_ISDIR(mode))
 845                 percpu_counter_inc(&sbi->s_dirs_counter);
 846         sb->s_dirt = 1;
 847
 848         if (sbi->s_log_groups_per_flex) {
 849                 flex_group = ext4_flex_group(sbi, group);
 850                 spin_lock(sb_bgl_lock(sbi, flex_group));
 851                 sbi->s_flex_groups[flex_group].free_inodes--;
 852                 spin_unlock(sb_bgl_lock(sbi, flex_group));
 853         }
 854
 855         inode->i_uid = current_fsuid();
 856         if (test_opt(sb, GRPID))
 857                 inode->i_gid = dir->i_gid;
 858         else if (dir->i_mode & S_ISGID) {
 859                 inode->i_gid = dir->i_gid;
 860                 if (S_ISDIR(mode))
 861                         mode |= S_ISGID;
 862         } else
 863                 inode->i_gid = current_fsgid();
 864         inode->i_mode = mode;
 865
 866         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
 867         /* This is the optimal IO size (for stat), not the fs block size */
 868         inode->i_blocks = 0;
 869         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
 870                                                        ext4_current_time(inode);
 871
 872         memset(ei->i_data, 0, sizeof(ei->i_data));
 873         ei->i_dir_start_lookup = 0;
 874         ei->i_disksize = 0;
 875
 876         /*
 877          * Don't inherit extent flag from directory. We set extent flag on
 878          * newly created directory and file only if -o extent mount option is
 879          * specified
 880          */
 881         ei->i_flags = EXT4_I(dir)->i_flags & ~(EXT4_INDEX_FL|EXT4_EXTENTS_FL);
 882         if (S_ISLNK(mode))
 883                 ei->i_flags &= ~(EXT4_IMMUTABLE_FL|EXT4_APPEND_FL);
 884         /* dirsync only applies to directories */
 885         if (!S_ISDIR(mode))
 886                 ei->i_flags &= ~EXT4_DIRSYNC_FL;
 887         ei->i_file_acl = 0;
 888         ei->i_dtime = 0;
 889         ei->i_block_group = group;
 890
 891         ext4_set_inode_flags(inode);
 892         if (IS_DIRSYNC(inode))
 893                 ext4_handle_sync(handle);
 894         if (insert_inode_locked(inode) < 0) {
 895                 err = -EINVAL;
 896                 goto fail_drop;
 897         }
 898         spin_lock(&sbi->s_next_gen_lock);
 899         inode->i_generation = sbi->s_next_generation++;
 900         spin_unlock(&sbi->s_next_gen_lock);
 901
 902         ei->i_state = EXT4_STATE_NEW;
 903
 904         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
 905
 906         ret = inode;
 907         if (DQUOT_ALLOC_INODE(inode)) {
 908                 err = -EDQUOT;
 909                 goto fail_drop;
 910         }
 911
 912         err = ext4_init_acl(handle, inode, dir);
 913         if (err)
 914                 goto fail_free_drop;
 915
 916         err = ext4_init_security(handle, inode, dir);
 917         if (err)
 918                 goto fail_free_drop;
 919
 920         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
 921                 /* set extent flag only for directory, file and normal symlink*/
 922                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
 923                         EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;
 924                         ext4_ext_tree_init(handle, inode);
 925                 }
 926         }
 927
 928         err = ext4_mark_inode_dirty(handle, inode);
 929         if (err) {
 930                 ext4_std_error(sb, err);
 931                 goto fail_free_drop;
 932         }
 933
 934         ext4_debug("allocating inode %lu\n", inode->i_ino);
 935         trace_mark(ext4_allocate_inode, "dev %s ino %lu dir %lu mode %d",
 936                    sb->s_id, inode->i_ino, dir->i_ino, mode);
 937         goto really_out;
 938 fail:
 939         ext4_std_error(sb, err);
 940 out:
 941         iput(inode);
 942         ret = ERR_PTR(err);
 943 really_out:
 944         brelse(inode_bitmap_bh);
 945         return ret;
 946
 947 fail_free_drop:
 948         DQUOT_FREE_INODE(inode);
 949
 950 fail_drop:
 951         DQUOT_DROP(inode);
 952         inode->i_flags |= S_NOQUOTA;
 953         inode->i_nlink = 0;
 954         unlock_new_inode(inode);
 955         iput(inode);
 956         brelse(inode_bitmap_bh);
 957         return ERR_PTR(err);
 958 }
 959
 960 /* Verify that we are loading a valid orphan from disk */
 961 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
 962 {
 963         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
 964         ext4_group_t block_group;
 965         int bit;
 966         struct buffer_head *bitmap_bh;
 967         struct inode *inode = NULL;
 968         long err = -EIO;
 969
 970         /* Error cases - e2fsck has already cleaned up for us */
 971         if (ino > max_ino) {
 972                 ext4_warning(sb, __func__,
 973                              "bad orphan ino %lu!  e2fsck was run?", ino);
 974                 goto error;
 975         }
 976
 977         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 978         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 979         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 980         if (!bitmap_bh) {
 981                 ext4_warning(sb, __func__,
 982                              "inode bitmap error for orphan %lu", ino);
 983                 goto error;
 984         }
 985
 986         /* Having the inode bit set should be a 100% indicator that this
 987          * is a valid orphan (no e2fsck run on fs).  Orphans also include
 988          * inodes that were being truncated, so we can't check i_nlink==0.
 989          */
 990         if (!ext4_test_bit(bit, bitmap_bh->b_data))
 991                 goto bad_orphan;
 992
 993         inode = ext4_iget(sb, ino);
 994         if (IS_ERR(inode))
 995                 goto iget_failed;
 996
 997         /*
 998          * If the orphans has i_nlinks > 0 then it should be able to be
 999          * truncated, otherwise it won't be removed from the orphan list
1000          * during processing and an infinite loop will result.
1001          */
1002         if (inode->i_nlink && !ext4_can_truncate(inode))
1003                 goto bad_orphan;
1004
1005         if (NEXT_ORPHAN(inode) > max_ino)
1006                 goto bad_orphan;
1007         brelse(bitmap_bh);
1008         return inode;
1009
1010 iget_failed:
1011         err = PTR_ERR(inode);
1012         inode = NULL;
1013 bad_orphan:
1014         ext4_warning(sb, __func__,
1015                      "bad orphan inode %lu!  e2fsck was run?", ino);
1016         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1017                bit, (unsigned long long)bitmap_bh->b_blocknr,
1018                ext4_test_bit(bit, bitmap_bh->b_data));
1019         printk(KERN_NOTICE "inode=%p\n", inode);
1020         if (inode) {
1021                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
1022                        is_bad_inode(inode));
1023                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
1024                        NEXT_ORPHAN(inode));
1025                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
1026                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
1027                 /* Avoid freeing blocks if we got a bad deleted inode */
1028                 if (inode->i_nlink == 0)
1029                         inode->i_blocks = 0;
1030                 iput(inode);
1031         }
1032         brelse(bitmap_bh);
1033 error:
1034         return ERR_PTR(err);
1035 }
1036
1037 unsigned long ext4_count_free_inodes(struct super_block *sb)
1038 {
1039         unsigned long desc_count;
1040         struct ext4_group_desc *gdp;
1041         ext4_group_t i;
1042 #ifdef EXT4FS_DEBUG
1043         struct ext4_super_block *es;
1044         unsigned long bitmap_count, x;
1045         struct buffer_head *bitmap_bh = NULL;
1046
1047         es = EXT4_SB(sb)->s_es;
1048         desc_count = 0;
1049         bitmap_count = 0;
1050         gdp = NULL;
1051         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1052                 gdp = ext4_get_group_desc(sb, i, NULL);
1053                 if (!gdp)
1054                         continue;
1055                 desc_count += ext4_free_inodes_count(sb, gdp);
1056                 brelse(bitmap_bh);
1057                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1058                 if (!bitmap_bh)
1059                         continue;
1060
1061                 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
1062                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1063                         i, ext4_free_inodes_count(sb, gdp), x);
1064                 bitmap_count += x;
1065         }
1066         brelse(bitmap_bh);
1067         printk(KERN_DEBUG "ext4_count_free_inodes: "
1068                "stored = %u, computed = %lu, %lu\n",
1069                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1070         return desc_count;
1071 #else
1072         desc_count = 0;
1073         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1074                 gdp = ext4_get_group_desc(sb, i, NULL);
1075                 if (!gdp)
1076                         continue;
1077                 desc_count += ext4_free_inodes_count(sb, gdp);
1078                 cond_resched();
1079         }
1080         return desc_count;
1081 #endif
1082 }
1083
1084 /* Called at mount-time, super-block is locked */
1085 unsigned long ext4_count_dirs(struct super_block * sb)
1086 {
1087         unsigned long count = 0;
1088         ext4_group_t i;
1089
1090         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1091                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1092                 if (!gdp)
1093                         continue;
1094                 count += ext4_used_dirs_count(sb, gdp);
1095         }
1096         return count;
1097 }