fs/ext3/ialloc.c - kernel/msm-4.9 - Gitiles

 /*
  *  linux/fs/ext3/ialloc.c
  *
  * Copyright (C) 1992, 1993, 1994, 1995
  * Remy Card (card@masi.ibp.fr)
  * Laboratoire MASI - Institut Blaise Pascal
  * Universite Pierre et Marie Curie (Paris VI)
  *
  *  BSD ufs-inspired inode and directory allocation by
  *  Stephen Tweedie (sct@redhat.com), 1993
  *  Big-endian to little-endian byte-swapping/bitmaps by
  *        David S. Miller (davem@caip.rutgers.edu), 1995
  */

 #include <linux/quotaops.h>
 #include <linux/random.h>

 #include "ext3.h"
 #include "xattr.h"
 #include "acl.h"

 /*
  * ialloc.c contains the inodes allocation and deallocation routines
  */

 /*
  * The free inodes are managed by bitmaps.  A file system contains several
  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  * block for inodes, N blocks for the inode table and data blocks.
  *
  * The file system contains group descriptors which are located after the
  * super block.  Each descriptor contains the number of the bitmap block and
  * the free blocks count in the block.
  */


 /*
  * Read the inode allocation bitmap for a given block_group, reading
  * into the specified slot in the superblock's bitmap cache.
  *
  * Return buffer_head of bitmap on success or NULL.
  */
 static struct buffer_head *
 read_inode_bitmap(struct super_block * sb, unsigned long block_group)
 {
 	struct ext3_group_desc *desc;
 	struct buffer_head *bh = NULL;

 	desc = ext3_get_group_desc(sb, block_group, NULL);
 	if (!desc)
 		goto error_out;

 	bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
 	if (!bh)
 		ext3_error(sb, "read_inode_bitmap",
 			    "Cannot read inode bitmap - "
 			    "block_group = %lu, inode_bitmap = %u",
 			    block_group, le32_to_cpu(desc->bg_inode_bitmap));
 error_out:
 	return bh;
 }

 /*
  * NOTE! When we get the inode, we're the only people
  * that have access to it, and as such there are no
  * race conditions we have to worry about. The inode
  * is not on the hash-lists, and it cannot be reached
  * through the filesystem because the directory entry
  * has been deleted earlier.
  *
  * HOWEVER: we must make sure that we get no aliases,
  * which means that we have to call "clear_inode()"
  * _before_ we mark the inode not in use in the inode
  * bitmaps. Otherwise a newly created file might use
  * the same inode number (not actually the same pointer
  * though), and then we'd have two inodes sharing the
  * same inode number and space on the harddisk.
  */
 void ext3_free_inode (handle_t *handle, struct inode * inode)
 {
 	struct super_block * sb = inode->i_sb;
 	int is_directory;
 	unsigned long ino;
 	struct buffer_head *bitmap_bh = NULL;
 	struct buffer_head *bh2;
 	unsigned long block_group;
 	unsigned long bit;
 	struct ext3_group_desc * gdp;
 	struct ext3_super_block * es;
 	struct ext3_sb_info *sbi;
 	int fatal = 0, err;

 	if (atomic_read(&inode->i_count) > 1) {
 		printk ("ext3_free_inode: inode has count=%d\n",
 					atomic_read(&inode->i_count));
 		return;
 	}
 	if (inode->i_nlink) {
 		printk ("ext3_free_inode: inode has nlink=%d\n",
 			inode->i_nlink);
 		return;
 	}
 	if (!sb) {
 		printk("ext3_free_inode: inode on nonexistent device\n");
 		return;
 	}
 	sbi = EXT3_SB(sb);

 	ino = inode->i_ino;
 	ext3_debug ("freeing inode %lu\n", ino);
 	trace_ext3_free_inode(inode);

 	is_directory = S_ISDIR(inode->i_mode);

 	es = EXT3_SB(sb)->s_es;
 	if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 		ext3_error (sb, "ext3_free_inode",
 			    "reserved or nonexistent inode %lu", ino);
 		goto error_return;
 	}
 	block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
 	bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
 	bitmap_bh = read_inode_bitmap(sb, block_group);
 	if (!bitmap_bh)
 		goto error_return;

 	BUFFER_TRACE(bitmap_bh, "get_write_access");
 	fatal = ext3_journal_get_write_access(handle, bitmap_bh);
 	if (fatal)
 		goto error_return;

 	/* Ok, now we can actually update the inode bitmaps.. */
 	if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
 					bit, bitmap_bh->b_data))
 		ext3_error (sb, "ext3_free_inode",
 			      "bit already cleared for inode %lu", ino);
 	else {
 		gdp = ext3_get_group_desc (sb, block_group, &bh2);

 		BUFFER_TRACE(bh2, "get_write_access");
 		fatal = ext3_journal_get_write_access(handle, bh2);
 		if (fatal) goto error_return;

 		if (gdp) {
 			spin_lock(sb_bgl_lock(sbi, block_group));
 			le16_add_cpu(&gdp->bg_free_inodes_count, 1);
 			if (is_directory)
 				le16_add_cpu(&gdp->bg_used_dirs_count, -1);
 			spin_unlock(sb_bgl_lock(sbi, block_group));
 			percpu_counter_inc(&sbi->s_freeinodes_counter);
 			if (is_directory)
 				percpu_counter_dec(&sbi->s_dirs_counter);

 		}
 		BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
 		err = ext3_journal_dirty_metadata(handle, bh2);
 		if (!fatal) fatal = err;
 	}
 	BUFFER_TRACE(bitmap_bh, "call ext3_journal_dirty_metadata");
 	err = ext3_journal_dirty_metadata(handle, bitmap_bh);
 	if (!fatal)
 		fatal = err;

 error_return:
 	brelse(bitmap_bh);
 	ext3_std_error(sb, fatal);
 }

 /*
  * Orlov's allocator for directories.
  *
  * We always try to spread first-level directories.
  *
  * If there are blockgroups with both free inodes and free blocks counts
  * not worse than average we return one with smallest directory count.
  * Otherwise we simply return a random group.
  *
  * For the rest rules look so:
  *
  * It's OK to put directory into a group unless
  * it has too many directories already (max_dirs) or
  * it has too few free inodes left (min_inodes) or
  * it has too few free blocks left (min_blocks).
  * Parent's group is preferred, if it doesn't satisfy these
  * conditions we search cyclically through the rest. If none
  * of the groups look good we just look for a group with more
  * free inodes than average (starting at parent's group).
  *
  * Debt is incremented each time we allocate a directory and decremented
  * when we allocate an inode, within 0--255.
  */

 static int find_group_orlov(struct super_block *sb, struct inode *parent)
 {
 	int parent_group = EXT3_I(parent)->i_block_group;
 	struct ext3_sb_info *sbi = EXT3_SB(sb);
 	int ngroups = sbi->s_groups_count;
 	int inodes_per_group = EXT3_INODES_PER_GROUP(sb);
 	unsigned int freei, avefreei;
 	ext3_fsblk_t freeb, avefreeb;
 	unsigned int ndirs;
 	int max_dirs, min_inodes;
 	ext3_grpblk_t min_blocks;
 	int group = -1, i;
 	struct ext3_group_desc *desc;

 	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 	avefreei = freei / ngroups;
 	freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 	avefreeb = freeb / ngroups;
 	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);

 	if ((parent == sb->s_root->d_inode) ||
 	    (EXT3_I(parent)->i_flags & EXT3_TOPDIR_FL)) {
 		int best_ndir = inodes_per_group;
 		int best_group = -1;

 		get_random_bytes(&group, sizeof(group));
 		parent_group = (unsigned)group % ngroups;
 		for (i = 0; i < ngroups; i++) {
 			group = (parent_group + i) % ngroups;
 			desc = ext3_get_group_desc (sb, group, NULL);
 			if (!desc || !desc->bg_free_inodes_count)
 				continue;
 			if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
 				continue;
 			if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
 				continue;
 			if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
 				continue;
 			best_group = group;
 			best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
 		}
 		if (best_group >= 0)
 			return best_group;
 		goto fallback;
 	}

 	max_dirs = ndirs / ngroups + inodes_per_group / 16;
 	min_inodes = avefreei - inodes_per_group / 4;
 	min_blocks = avefreeb - EXT3_BLOCKS_PER_GROUP(sb) / 4;

 	for (i = 0; i < ngroups; i++) {
 		group = (parent_group + i) % ngroups;
 		desc = ext3_get_group_desc (sb, group, NULL);
 		if (!desc || !desc->bg_free_inodes_count)
 			continue;
 		if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
 			continue;
 		if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
 			continue;
 		if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
 			continue;
 		return group;
 	}

 fallback:
 	for (i = 0; i < ngroups; i++) {
 		group = (parent_group + i) % ngroups;
 		desc = ext3_get_group_desc (sb, group, NULL);
 		if (!desc || !desc->bg_free_inodes_count)
 			continue;
 		if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
 			return group;
 	}

 	if (avefreei) {
 		/*
 		 * The free-inodes counter is approximate, and for really small
 		 * filesystems the above test can fail to find any blockgroups
 		 */
 		avefreei = 0;
 		goto fallback;
 	}

 	return -1;
 }

 static int find_group_other(struct super_block *sb, struct inode *parent)
 {
 	int parent_group = EXT3_I(parent)->i_block_group;
 	int ngroups = EXT3_SB(sb)->s_groups_count;
 	struct ext3_group_desc *desc;
 	int group, i;

 	/*
 	 * Try to place the inode in its parent directory
 	 */
 	group = parent_group;
 	desc = ext3_get_group_desc (sb, group, NULL);
 	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 			le16_to_cpu(desc->bg_free_blocks_count))
 		return group;

 	/*
 	 * We're going to place this inode in a different blockgroup from its
 	 * parent.  We want to cause files in a common directory to all land in
 	 * the same blockgroup.  But we want files which are in a different
 	 * directory which shares a blockgroup with our parent to land in a
 	 * different blockgroup.
 	 *
 	 * So add our directory's i_ino into the starting point for the hash.
 	 */
 	group = (group + parent->i_ino) % ngroups;

 	/*
 	 * Use a quadratic hash to find a group with a free inode and some free
 	 * blocks.
 	 */
 	for (i = 1; i < ngroups; i <<= 1) {
 		group += i;
 		if (group >= ngroups)
 			group -= ngroups;
 		desc = ext3_get_group_desc (sb, group, NULL);
 		if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 				le16_to_cpu(desc->bg_free_blocks_count))
 			return group;
 	}

 	/*
 	 * That failed: try linear search for a free inode, even if that group
 	 * has no free blocks.
 	 */
 	group = parent_group;
 	for (i = 0; i < ngroups; i++) {
 		if (++group >= ngroups)
 			group = 0;
 		desc = ext3_get_group_desc (sb, group, NULL);
 		if (desc && le16_to_cpu(desc->bg_free_inodes_count))
 			return group;
 	}

 	return -1;
 }

 /*
  * There are two policies for allocating an inode.  If the new inode is
  * a directory, then a forward search is made for a block group with both
  * free space and a low directory-to-inode ratio; if that fails, then of
  * the groups with above-average free space, that group with the fewest
  * directories already is chosen.
  *
  * For other inodes, search forward from the parent directory's block
  * group to find a free inode.
  */
 struct inode *ext3_new_inode(handle_t *handle, struct inode * dir,
 			     const struct qstr *qstr, umode_t mode)
 {
 	struct super_block *sb;
 	struct buffer_head *bitmap_bh = NULL;
 	struct buffer_head *bh2;
 	int group;
 	unsigned long ino = 0;
 	struct inode * inode;
 	struct ext3_group_desc * gdp = NULL;
 	struct ext3_super_block * es;
 	struct ext3_inode_info *ei;
 	struct ext3_sb_info *sbi;
 	int err = 0;
 	struct inode *ret;
 	int i;

 	/* Cannot create files in a deleted directory */
 	if (!dir || !dir->i_nlink)
 		return ERR_PTR(-EPERM);

 	sb = dir->i_sb;
 	trace_ext3_request_inode(dir, mode);
 	inode = new_inode(sb);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 	ei = EXT3_I(inode);

 	sbi = EXT3_SB(sb);
 	es = sbi->s_es;
 	if (S_ISDIR(mode))
 		group = find_group_orlov(sb, dir);
 	else
 		group = find_group_other(sb, dir);

 	err = -ENOSPC;
 	if (group == -1)
 		goto out;

 	for (i = 0; i < sbi->s_groups_count; i++) {
 		err = -EIO;

 		gdp = ext3_get_group_desc(sb, group, &bh2);
 		if (!gdp)
 			goto fail;

 		brelse(bitmap_bh);
 		bitmap_bh = read_inode_bitmap(sb, group);
 		if (!bitmap_bh)
 			goto fail;

 		ino = 0;

 repeat_in_this_group:
 		ino = ext3_find_next_zero_bit((unsigned long *)
 				bitmap_bh->b_data, EXT3_INODES_PER_GROUP(sb), ino);
 		if (ino < EXT3_INODES_PER_GROUP(sb)) {

 			BUFFER_TRACE(bitmap_bh, "get_write_access");
 			err = ext3_journal_get_write_access(handle, bitmap_bh);
 			if (err)
 				goto fail;

 			if (!ext3_set_bit_atomic(sb_bgl_lock(sbi, group),
 						ino, bitmap_bh->b_data)) {
 				/* we won it */
 				BUFFER_TRACE(bitmap_bh,
 					"call ext3_journal_dirty_metadata");
 				err = ext3_journal_dirty_metadata(handle,
 								bitmap_bh);
 				if (err)
 					goto fail;
 				goto got;
 			}
 			/* we lost it */
 			journal_release_buffer(handle, bitmap_bh);

 			if (++ino < EXT3_INODES_PER_GROUP(sb))
 				goto repeat_in_this_group;
 		}

 		/*
 		 * This case is possible in concurrent environment.  It is very
 		 * rare.  We cannot repeat the find_group_xxx() call because
 		 * that will simply return the same blockgroup, because the
 		 * group descriptor metadata has not yet been updated.
 		 * So we just go onto the next blockgroup.
 		 */
 		if (++group == sbi->s_groups_count)
 			group = 0;
 	}
 	err = -ENOSPC;
 	goto out;

 got:
 	ino += group * EXT3_INODES_PER_GROUP(sb) + 1;
 	if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 		ext3_error (sb, "ext3_new_inode",
 			    "reserved inode or inode > inodes count - "
 			    "block_group = %d, inode=%lu", group, ino);
 		err = -EIO;
 		goto fail;
 	}

 	BUFFER_TRACE(bh2, "get_write_access");
 	err = ext3_journal_get_write_access(handle, bh2);
 	if (err) goto fail;
 	spin_lock(sb_bgl_lock(sbi, group));
 	le16_add_cpu(&gdp->bg_free_inodes_count, -1);
 	if (S_ISDIR(mode)) {
 		le16_add_cpu(&gdp->bg_used_dirs_count, 1);
 	}
 	spin_unlock(sb_bgl_lock(sbi, group));
 	BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
 	err = ext3_journal_dirty_metadata(handle, bh2);
 	if (err) goto fail;

 	percpu_counter_dec(&sbi->s_freeinodes_counter);
 	if (S_ISDIR(mode))
 		percpu_counter_inc(&sbi->s_dirs_counter);


 	if (test_opt(sb, GRPID)) {
 		inode->i_mode = mode;
 		inode->i_uid = current_fsuid();
 		inode->i_gid = dir->i_gid;
 	} else
 		inode_init_owner(inode, dir, mode);

 	inode->i_ino = ino;
 	/* This is the optimal IO size (for stat), not the fs block size */
 	inode->i_blocks = 0;
 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;

 	memset(ei->i_data, 0, sizeof(ei->i_data));
 	ei->i_dir_start_lookup = 0;
 	ei->i_disksize = 0;

 	ei->i_flags =
 		ext3_mask_flags(mode, EXT3_I(dir)->i_flags & EXT3_FL_INHERITED);
 #ifdef EXT3_FRAGMENTS
 	ei->i_faddr = 0;
 	ei->i_frag_no = 0;
 	ei->i_frag_size = 0;
 #endif
 	ei->i_file_acl = 0;
 	ei->i_dir_acl = 0;
 	ei->i_dtime = 0;
 	ei->i_block_alloc_info = NULL;
 	ei->i_block_group = group;

 	ext3_set_inode_flags(inode);
 	if (IS_DIRSYNC(inode))
 		handle->h_sync = 1;
 	if (insert_inode_locked(inode) < 0) {
 		/*
 		 * Likely a bitmap corruption causing inode to be allocated
 		 * twice.
 		 */
 		err = -EIO;
 		goto fail;
 	}
 	spin_lock(&sbi->s_next_gen_lock);
 	inode->i_generation = sbi->s_next_generation++;
 	spin_unlock(&sbi->s_next_gen_lock);

 	ei->i_state_flags = 0;
 	ext3_set_inode_state(inode, EXT3_STATE_NEW);

 	/* See comment in ext3_iget for explanation */
 	if (ino >= EXT3_FIRST_INO(sb) + 1 &&
 	    EXT3_INODE_SIZE(sb) > EXT3_GOOD_OLD_INODE_SIZE) {
 		ei->i_extra_isize =
 			sizeof(struct ext3_inode) - EXT3_GOOD_OLD_INODE_SIZE;
 	} else {
 		ei->i_extra_isize = 0;
 	}

 	ret = inode;
 	dquot_initialize(inode);
 	err = dquot_alloc_inode(inode);
 	if (err)
 		goto fail_drop;

 	err = ext3_init_acl(handle, inode, dir);
 	if (err)
 		goto fail_free_drop;

 	err = ext3_init_security(handle, inode, dir, qstr);
 	if (err)
 		goto fail_free_drop;

 	err = ext3_mark_inode_dirty(handle, inode);
 	if (err) {
 		ext3_std_error(sb, err);
 		goto fail_free_drop;
 	}

 	ext3_debug("allocating inode %lu\n", inode->i_ino);
 	trace_ext3_allocate_inode(inode, dir, mode);
 	goto really_out;
 fail:
 	ext3_std_error(sb, err);
 out:
 	iput(inode);
 	ret = ERR_PTR(err);
 really_out:
 	brelse(bitmap_bh);
 	return ret;

 fail_free_drop:
 	dquot_free_inode(inode);

 fail_drop:
 	dquot_drop(inode);
 	inode->i_flags |= S_NOQUOTA;
 	clear_nlink(inode);
 	unlock_new_inode(inode);
 	iput(inode);
 	brelse(bitmap_bh);
 	return ERR_PTR(err);
 }

 /* Verify that we are loading a valid orphan from disk */
 struct inode *ext3_orphan_get(struct super_block *sb, unsigned long ino)
 {
 	unsigned long max_ino = le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count);
 	unsigned long block_group;
 	int bit;
 	struct buffer_head *bitmap_bh;
 	struct inode *inode = NULL;
 	long err = -EIO;

 	/* Error cases - e2fsck has already cleaned up for us */
 	if (ino > max_ino) {
 		ext3_warning(sb, __func__,
 			     "bad orphan ino %lu!  e2fsck was run?", ino);
 		goto error;
 	}

 	block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
 	bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
 	bitmap_bh = read_inode_bitmap(sb, block_group);
 	if (!bitmap_bh) {
 		ext3_warning(sb, __func__,
 			     "inode bitmap error for orphan %lu", ino);
 		goto error;
 	}

 	/* Having the inode bit set should be a 100% indicator that this
 	 * is a valid orphan (no e2fsck run on fs).  Orphans also include
 	 * inodes that were being truncated, so we can't check i_nlink==0.
 	 */
 	if (!ext3_test_bit(bit, bitmap_bh->b_data))
 		goto bad_orphan;

 	inode = ext3_iget(sb, ino);
 	if (IS_ERR(inode))
 		goto iget_failed;

 	/*
 	 * If the orphans has i_nlinks > 0 then it should be able to be
 	 * truncated, otherwise it won't be removed from the orphan list
 	 * during processing and an infinite loop will result.
 	 */
 	if (inode->i_nlink && !ext3_can_truncate(inode))
 		goto bad_orphan;

 	if (NEXT_ORPHAN(inode) > max_ino)
 		goto bad_orphan;
 	brelse(bitmap_bh);
 	return inode;

 iget_failed:
 	err = PTR_ERR(inode);
 	inode = NULL;
 bad_orphan:
 	ext3_warning(sb, __func__,
 		     "bad orphan inode %lu!  e2fsck was run?", ino);
 	printk(KERN_NOTICE "ext3_test_bit(bit=%d, block=%llu) = %d\n",
 	       bit, (unsigned long long)bitmap_bh->b_blocknr,
 	       ext3_test_bit(bit, bitmap_bh->b_data));
 	printk(KERN_NOTICE "inode=%p\n", inode);
 	if (inode) {
 		printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
 		       is_bad_inode(inode));
 		printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
 		       NEXT_ORPHAN(inode));
 		printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
 		printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
 		/* Avoid freeing blocks if we got a bad deleted inode */
 		if (inode->i_nlink == 0)
 			inode->i_blocks = 0;
 		iput(inode);
 	}
 	brelse(bitmap_bh);
 error:
 	return ERR_PTR(err);
 }

 unsigned long ext3_count_free_inodes (struct super_block * sb)
 {
 	unsigned long desc_count;
 	struct ext3_group_desc *gdp;
 	int i;
 #ifdef EXT3FS_DEBUG
 	struct ext3_super_block *es;
 	unsigned long bitmap_count, x;
 	struct buffer_head *bitmap_bh = NULL;

 	es = EXT3_SB(sb)->s_es;
 	desc_count = 0;
 	bitmap_count = 0;
 	gdp = NULL;
 	for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
 		gdp = ext3_get_group_desc (sb, i, NULL);
 		if (!gdp)
 			continue;
 		desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
 		brelse(bitmap_bh);
 		bitmap_bh = read_inode_bitmap(sb, i);
 		if (!bitmap_bh)
 			continue;

 		x = ext3_count_free(bitmap_bh, EXT3_INODES_PER_GROUP(sb) / 8);
 		printk("group %d: stored = %d, counted = %lu\n",
 			i, le16_to_cpu(gdp->bg_free_inodes_count), x);
 		bitmap_count += x;
 	}
 	brelse(bitmap_bh);
 	printk("ext3_count_free_inodes: stored = %u, computed = %lu, %lu\n",
 		le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
 	return desc_count;
 #else
 	desc_count = 0;
 	for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
 		gdp = ext3_get_group_desc (sb, i, NULL);
 		if (!gdp)
 			continue;
 		desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
 		cond_resched();
 	}
 	return desc_count;
 #endif
 }

 /* Called at mount-time, super-block is locked */
 unsigned long ext3_count_dirs (struct super_block * sb)
 {
 	unsigned long count = 0;
 	int i;

 	for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
 		struct ext3_group_desc *gdp = ext3_get_group_desc (sb, i, NULL);
 		if (!gdp)
 			continue;
 		count += le16_to_cpu(gdp->bg_used_dirs_count);
 	}
 	return count;
 }
	/*
	* linux/fs/ext3/ialloc.c
	*
	* Copyright (C) 1992, 1993, 1994, 1995
	* Remy Card (card@masi.ibp.fr)
	* Laboratoire MASI - Institut Blaise Pascal
	* Universite Pierre et Marie Curie (Paris VI)
	*
	* BSD ufs-inspired inode and directory allocation by
	* Stephen Tweedie (sct@redhat.com), 1993
	* Big-endian to little-endian byte-swapping/bitmaps by
	* David S. Miller (davem@caip.rutgers.edu), 1995
	*/

	#include <linux/quotaops.h>
	#include <linux/random.h>

	#include "ext3.h"
	#include "xattr.h"
	#include "acl.h"

	/*
	* ialloc.c contains the inodes allocation and deallocation routines
	*/

	/*
	* The free inodes are managed by bitmaps. A file system contains several
	* blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
	* block for inodes, N blocks for the inode table and data blocks.
	*
	* The file system contains group descriptors which are located after the
	* super block. Each descriptor contains the number of the bitmap block and
	* the free blocks count in the block.
	*/


	/*
	* Read the inode allocation bitmap for a given block_group, reading
	* into the specified slot in the superblock's bitmap cache.
	*
	* Return buffer_head of bitmap on success or NULL.
	*/
	static struct buffer_head *
	read_inode_bitmap(struct super_block * sb, unsigned long block_group)
	{
	struct ext3_group_desc *desc;
	struct buffer_head *bh = NULL;

	desc = ext3_get_group_desc(sb, block_group, NULL);
	if (!desc)
	goto error_out;

	bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
	if (!bh)
	ext3_error(sb, "read_inode_bitmap",
	"Cannot read inode bitmap - "
	"block_group = %lu, inode_bitmap = %u",
	block_group, le32_to_cpu(desc->bg_inode_bitmap));
	error_out:
	return bh;
	}

	/*
	* NOTE! When we get the inode, we're the only people
	* that have access to it, and as such there are no
	* race conditions we have to worry about. The inode
	* is not on the hash-lists, and it cannot be reached
	* through the filesystem because the directory entry
	* has been deleted earlier.
	*
	* HOWEVER: we must make sure that we get no aliases,
	* which means that we have to call "clear_inode()"
	* _before_ we mark the inode not in use in the inode
	* bitmaps. Otherwise a newly created file might use
	* the same inode number (not actually the same pointer
	* though), and then we'd have two inodes sharing the
	* same inode number and space on the harddisk.
	*/
	void ext3_free_inode (handle_t handle, struct inode inode)
	{
	struct super_block * sb = inode->i_sb;
	int is_directory;
	unsigned long ino;
	struct buffer_head *bitmap_bh = NULL;
	struct buffer_head *bh2;
	unsigned long block_group;
	unsigned long bit;
	struct ext3_group_desc * gdp;
	struct ext3_super_block * es;
	struct ext3_sb_info *sbi;
	int fatal = 0, err;

	if (atomic_read(&inode->i_count) > 1) {
	printk ("ext3_free_inode: inode has count=%d\n",
	atomic_read(&inode->i_count));
	return;
	}
	if (inode->i_nlink) {
	printk ("ext3_free_inode: inode has nlink=%d\n",
	inode->i_nlink);
	return;
	}
	if (!sb) {
	printk("ext3_free_inode: inode on nonexistent device\n");
	return;
	}
	sbi = EXT3_SB(sb);

	ino = inode->i_ino;
	ext3_debug ("freeing inode %lu\n", ino);
	trace_ext3_free_inode(inode);

	is_directory = S_ISDIR(inode->i_mode);

	es = EXT3_SB(sb)->s_es;
	if (ino < EXT3_FIRST_INO(sb) \|\| ino > le32_to_cpu(es->s_inodes_count)) {
	ext3_error (sb, "ext3_free_inode",
	"reserved or nonexistent inode %lu", ino);
	goto error_return;
	}
	block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
	bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
	bitmap_bh = read_inode_bitmap(sb, block_group);
	if (!bitmap_bh)
	goto error_return;

	BUFFER_TRACE(bitmap_bh, "get_write_access");
	fatal = ext3_journal_get_write_access(handle, bitmap_bh);
	if (fatal)
	goto error_return;

	/* Ok, now we can actually update the inode bitmaps.. */
	if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
	bit, bitmap_bh->b_data))
	ext3_error (sb, "ext3_free_inode",
	"bit already cleared for inode %lu", ino);
	else {
	gdp = ext3_get_group_desc (sb, block_group, &bh2);

	BUFFER_TRACE(bh2, "get_write_access");
	fatal = ext3_journal_get_write_access(handle, bh2);
	if (fatal) goto error_return;

	if (gdp) {
	spin_lock(sb_bgl_lock(sbi, block_group));
	le16_add_cpu(&gdp->bg_free_inodes_count, 1);
	if (is_directory)
	le16_add_cpu(&gdp->bg_used_dirs_count, -1);
	spin_unlock(sb_bgl_lock(sbi, block_group));
	percpu_counter_inc(&sbi->s_freeinodes_counter);
	if (is_directory)
	percpu_counter_dec(&sbi->s_dirs_counter);

	}
	BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
	err = ext3_journal_dirty_metadata(handle, bh2);
	if (!fatal) fatal = err;
	}
	BUFFER_TRACE(bitmap_bh, "call ext3_journal_dirty_metadata");
	err = ext3_journal_dirty_metadata(handle, bitmap_bh);
	if (!fatal)
	fatal = err;

	error_return:
	brelse(bitmap_bh);
	ext3_std_error(sb, fatal);
	}

	/*
	* Orlov's allocator for directories.
	*
	* We always try to spread first-level directories.
	*
	* If there are blockgroups with both free inodes and free blocks counts
	* not worse than average we return one with smallest directory count.
	* Otherwise we simply return a random group.
	*
	* For the rest rules look so:
	*
	* It's OK to put directory into a group unless
	* it has too many directories already (max_dirs) or
	* it has too few free inodes left (min_inodes) or
	* it has too few free blocks left (min_blocks).
	* Parent's group is preferred, if it doesn't satisfy these
	* conditions we search cyclically through the rest. If none
	* of the groups look good we just look for a group with more
	* free inodes than average (starting at parent's group).
	*
	* Debt is incremented each time we allocate a directory and decremented
	* when we allocate an inode, within 0--255.
	*/

	static int find_group_orlov(struct super_block sb, struct inode parent)
	{
	int parent_group = EXT3_I(parent)->i_block_group;
	struct ext3_sb_info *sbi = EXT3_SB(sb);
	int ngroups = sbi->s_groups_count;
	int inodes_per_group = EXT3_INODES_PER_GROUP(sb);
	unsigned int freei, avefreei;
	ext3_fsblk_t freeb, avefreeb;
	unsigned int ndirs;
	int max_dirs, min_inodes;
	ext3_grpblk_t min_blocks;
	int group = -1, i;
	struct ext3_group_desc *desc;

	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
	avefreei = freei / ngroups;
	freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
	avefreeb = freeb / ngroups;
	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);

	if ((parent == sb->s_root->d_inode) \|\|
	(EXT3_I(parent)->i_flags & EXT3_TOPDIR_FL)) {
	int best_ndir = inodes_per_group;
	int best_group = -1;

	get_random_bytes(&group, sizeof(group));
	parent_group = (unsigned)group % ngroups;
	for (i = 0; i < ngroups; i++) {
	group = (parent_group + i) % ngroups;
	desc = ext3_get_group_desc (sb, group, NULL);
	if (!desc \|\| !desc->bg_free_inodes_count)
	continue;
	if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
	continue;
	if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
	continue;
	if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
	continue;
	best_group = group;
	best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
	}
	if (best_group >= 0)
	return best_group;
	goto fallback;
	}

	max_dirs = ndirs / ngroups + inodes_per_group / 16;
	min_inodes = avefreei - inodes_per_group / 4;
	min_blocks = avefreeb - EXT3_BLOCKS_PER_GROUP(sb) / 4;

	for (i = 0; i < ngroups; i++) {
	group = (parent_group + i) % ngroups;
	desc = ext3_get_group_desc (sb, group, NULL);
	if (!desc \|\| !desc->bg_free_inodes_count)
	continue;
	if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
	continue;
	if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
	continue;
	if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
	continue;
	return group;
	}

	fallback:
	for (i = 0; i < ngroups; i++) {
	group = (parent_group + i) % ngroups;
	desc = ext3_get_group_desc (sb, group, NULL);
	if (!desc \|\| !desc->bg_free_inodes_count)
	continue;
	if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
	return group;
	}

	if (avefreei) {
	/*
	* The free-inodes counter is approximate, and for really small
	* filesystems the above test can fail to find any blockgroups
	*/
	avefreei = 0;
	goto fallback;
	}

	return -1;
	}

	static int find_group_other(struct super_block sb, struct inode parent)
	{
	int parent_group = EXT3_I(parent)->i_block_group;
	int ngroups = EXT3_SB(sb)->s_groups_count;
	struct ext3_group_desc *desc;
	int group, i;

	/*
	* Try to place the inode in its parent directory
	*/
	group = parent_group;
	desc = ext3_get_group_desc (sb, group, NULL);
	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
	le16_to_cpu(desc->bg_free_blocks_count))
	return group;

	/*
	* We're going to place this inode in a different blockgroup from its
	* parent. We want to cause files in a common directory to all land in
	* the same blockgroup. But we want files which are in a different
	* directory which shares a blockgroup with our parent to land in a
	* different blockgroup.
	*
	* So add our directory's i_ino into the starting point for the hash.
	*/
	group = (group + parent->i_ino) % ngroups;

	/*
	* Use a quadratic hash to find a group with a free inode and some free
	* blocks.
	*/
	for (i = 1; i < ngroups; i <<= 1) {
	group += i;
	if (group >= ngroups)
	group -= ngroups;
	desc = ext3_get_group_desc (sb, group, NULL);
	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
	le16_to_cpu(desc->bg_free_blocks_count))
	return group;
	}

	/*
	* That failed: try linear search for a free inode, even if that group
	* has no free blocks.
	*/
	group = parent_group;
	for (i = 0; i < ngroups; i++) {
	if (++group >= ngroups)
	group = 0;
	desc = ext3_get_group_desc (sb, group, NULL);
	if (desc && le16_to_cpu(desc->bg_free_inodes_count))
	return group;
	}

	return -1;
	}

	/*
	* There are two policies for allocating an inode. If the new inode is
	* a directory, then a forward search is made for a block group with both
	* free space and a low directory-to-inode ratio; if that fails, then of
	* the groups with above-average free space, that group with the fewest
	* directories already is chosen.
	*
	* For other inodes, search forward from the parent directory's block
	* group to find a free inode.
	*/
	struct inode ext3_new_inode(handle_t handle, struct inode * dir,
	const struct qstr *qstr, umode_t mode)
	{
	struct super_block *sb;
	struct buffer_head *bitmap_bh = NULL;
	struct buffer_head *bh2;
	int group;
	unsigned long ino = 0;
	struct inode * inode;
	struct ext3_group_desc * gdp = NULL;
	struct ext3_super_block * es;
	struct ext3_inode_info *ei;
	struct ext3_sb_info *sbi;
	int err = 0;
	struct inode *ret;
	int i;

	/* Cannot create files in a deleted directory */
	if (!dir \|\| !dir->i_nlink)
	return ERR_PTR(-EPERM);

	sb = dir->i_sb;
	trace_ext3_request_inode(dir, mode);
	inode = new_inode(sb);
	if (!inode)
	return ERR_PTR(-ENOMEM);
	ei = EXT3_I(inode);

	sbi = EXT3_SB(sb);
	es = sbi->s_es;
	if (S_ISDIR(mode))
	group = find_group_orlov(sb, dir);
	else
	group = find_group_other(sb, dir);

	err = -ENOSPC;
	if (group == -1)
	goto out;

	for (i = 0; i < sbi->s_groups_count; i++) {
	err = -EIO;

	gdp = ext3_get_group_desc(sb, group, &bh2);
	if (!gdp)
	goto fail;

	brelse(bitmap_bh);
	bitmap_bh = read_inode_bitmap(sb, group);
	if (!bitmap_bh)
	goto fail;

	ino = 0;

	repeat_in_this_group:
	ino = ext3_find_next_zero_bit((unsigned long *)
	bitmap_bh->b_data, EXT3_INODES_PER_GROUP(sb), ino);
	if (ino < EXT3_INODES_PER_GROUP(sb)) {

	BUFFER_TRACE(bitmap_bh, "get_write_access");
	err = ext3_journal_get_write_access(handle, bitmap_bh);
	if (err)
	goto fail;

	if (!ext3_set_bit_atomic(sb_bgl_lock(sbi, group),
	ino, bitmap_bh->b_data)) {
	/* we won it */
	BUFFER_TRACE(bitmap_bh,
	"call ext3_journal_dirty_metadata");
	err = ext3_journal_dirty_metadata(handle,
	bitmap_bh);
	if (err)
	goto fail;
	goto got;
	}
	/* we lost it */
	journal_release_buffer(handle, bitmap_bh);

	if (++ino < EXT3_INODES_PER_GROUP(sb))
	goto repeat_in_this_group;
	}

	/*
	* This case is possible in concurrent environment. It is very
	* rare. We cannot repeat the find_group_xxx() call because
	* that will simply return the same blockgroup, because the
	* group descriptor metadata has not yet been updated.
	* So we just go onto the next blockgroup.
	*/
	if (++group == sbi->s_groups_count)
	group = 0;
	}
	err = -ENOSPC;
	goto out;

	got:
	ino += group * EXT3_INODES_PER_GROUP(sb) + 1;
	if (ino < EXT3_FIRST_INO(sb) \|\| ino > le32_to_cpu(es->s_inodes_count)) {
	ext3_error (sb, "ext3_new_inode",
	"reserved inode or inode > inodes count - "
	"block_group = %d, inode=%lu", group, ino);
	err = -EIO;
	goto fail;
	}

	BUFFER_TRACE(bh2, "get_write_access");
	err = ext3_journal_get_write_access(handle, bh2);
	if (err) goto fail;
	spin_lock(sb_bgl_lock(sbi, group));
	le16_add_cpu(&gdp->bg_free_inodes_count, -1);
	if (S_ISDIR(mode)) {
	le16_add_cpu(&gdp->bg_used_dirs_count, 1);
	}
	spin_unlock(sb_bgl_lock(sbi, group));
	BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
	err = ext3_journal_dirty_metadata(handle, bh2);
	if (err) goto fail;

	percpu_counter_dec(&sbi->s_freeinodes_counter);
	if (S_ISDIR(mode))
	percpu_counter_inc(&sbi->s_dirs_counter);


	if (test_opt(sb, GRPID)) {
	inode->i_mode = mode;
	inode->i_uid = current_fsuid();
	inode->i_gid = dir->i_gid;
	} else
	inode_init_owner(inode, dir, mode);

	inode->i_ino = ino;
	/* This is the optimal IO size (for stat), not the fs block size */
	inode->i_blocks = 0;
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;

	memset(ei->i_data, 0, sizeof(ei->i_data));
	ei->i_dir_start_lookup = 0;
	ei->i_disksize = 0;

	ei->i_flags =
	ext3_mask_flags(mode, EXT3_I(dir)->i_flags & EXT3_FL_INHERITED);
	#ifdef EXT3_FRAGMENTS
	ei->i_faddr = 0;
	ei->i_frag_no = 0;
	ei->i_frag_size = 0;
	#endif
	ei->i_file_acl = 0;
	ei->i_dir_acl = 0;
	ei->i_dtime = 0;
	ei->i_block_alloc_info = NULL;
	ei->i_block_group = group;

	ext3_set_inode_flags(inode);
	if (IS_DIRSYNC(inode))
	handle->h_sync = 1;
	if (insert_inode_locked(inode) < 0) {
	/*
	* Likely a bitmap corruption causing inode to be allocated
	* twice.
	*/
	err = -EIO;
	goto fail;
	}
	spin_lock(&sbi->s_next_gen_lock);
	inode->i_generation = sbi->s_next_generation++;
	spin_unlock(&sbi->s_next_gen_lock);

	ei->i_state_flags = 0;
	ext3_set_inode_state(inode, EXT3_STATE_NEW);

	/* See comment in ext3_iget for explanation */
	if (ino >= EXT3_FIRST_INO(sb) + 1 &&
	EXT3_INODE_SIZE(sb) > EXT3_GOOD_OLD_INODE_SIZE) {
	ei->i_extra_isize =
	sizeof(struct ext3_inode) - EXT3_GOOD_OLD_INODE_SIZE;
	} else {
	ei->i_extra_isize = 0;
	}

	ret = inode;
	dquot_initialize(inode);
	err = dquot_alloc_inode(inode);
	if (err)
	goto fail_drop;

	err = ext3_init_acl(handle, inode, dir);
	if (err)
	goto fail_free_drop;

	err = ext3_init_security(handle, inode, dir, qstr);
	if (err)
	goto fail_free_drop;

	err = ext3_mark_inode_dirty(handle, inode);
	if (err) {
	ext3_std_error(sb, err);
	goto fail_free_drop;
	}

	ext3_debug("allocating inode %lu\n", inode->i_ino);
	trace_ext3_allocate_inode(inode, dir, mode);
	goto really_out;
	fail:
	ext3_std_error(sb, err);
	out:
	iput(inode);
	ret = ERR_PTR(err);
	really_out:
	brelse(bitmap_bh);
	return ret;

	fail_free_drop:
	dquot_free_inode(inode);

	fail_drop:
	dquot_drop(inode);
	inode->i_flags \|= S_NOQUOTA;
	clear_nlink(inode);
	unlock_new_inode(inode);
	iput(inode);
	brelse(bitmap_bh);
	return ERR_PTR(err);
	}

	/* Verify that we are loading a valid orphan from disk */
	struct inode ext3_orphan_get(struct super_block sb, unsigned long ino)
	{
	unsigned long max_ino = le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count);
	unsigned long block_group;
	int bit;
	struct buffer_head *bitmap_bh;
	struct inode *inode = NULL;
	long err = -EIO;

	/* Error cases - e2fsck has already cleaned up for us */
	if (ino > max_ino) {
	ext3_warning(sb, __func__,
	"bad orphan ino %lu! e2fsck was run?", ino);
	goto error;
	}

	block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
	bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
	bitmap_bh = read_inode_bitmap(sb, block_group);
	if (!bitmap_bh) {
	ext3_warning(sb, __func__,
	"inode bitmap error for orphan %lu", ino);
	goto error;
	}

	/* Having the inode bit set should be a 100% indicator that this
	* is a valid orphan (no e2fsck run on fs). Orphans also include
	* inodes that were being truncated, so we can't check i_nlink==0.
	*/
	if (!ext3_test_bit(bit, bitmap_bh->b_data))
	goto bad_orphan;

	inode = ext3_iget(sb, ino);
	if (IS_ERR(inode))
	goto iget_failed;

	/*
	* If the orphans has i_nlinks > 0 then it should be able to be
	* truncated, otherwise it won't be removed from the orphan list
	* during processing and an infinite loop will result.
	*/
	if (inode->i_nlink && !ext3_can_truncate(inode))
	goto bad_orphan;

	if (NEXT_ORPHAN(inode) > max_ino)
	goto bad_orphan;
	brelse(bitmap_bh);
	return inode;

	iget_failed:
	err = PTR_ERR(inode);
	inode = NULL;
	bad_orphan:
	ext3_warning(sb, __func__,
	"bad orphan inode %lu! e2fsck was run?", ino);
	printk(KERN_NOTICE "ext3_test_bit(bit=%d, block=%llu) = %d\n",
	bit, (unsigned long long)bitmap_bh->b_blocknr,
	ext3_test_bit(bit, bitmap_bh->b_data));
	printk(KERN_NOTICE "inode=%p\n", inode);
	if (inode) {
	printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
	is_bad_inode(inode));
	printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
	NEXT_ORPHAN(inode));
	printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
	printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
	/* Avoid freeing blocks if we got a bad deleted inode */
	if (inode->i_nlink == 0)
	inode->i_blocks = 0;
	iput(inode);
	}
	brelse(bitmap_bh);
	error:
	return ERR_PTR(err);
	}

	unsigned long ext3_count_free_inodes (struct super_block * sb)
	{
	unsigned long desc_count;
	struct ext3_group_desc *gdp;
	int i;
	#ifdef EXT3FS_DEBUG
	struct ext3_super_block *es;
	unsigned long bitmap_count, x;
	struct buffer_head *bitmap_bh = NULL;

	es = EXT3_SB(sb)->s_es;
	desc_count = 0;
	bitmap_count = 0;
	gdp = NULL;
	for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
	gdp = ext3_get_group_desc (sb, i, NULL);
	if (!gdp)
	continue;
	desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
	brelse(bitmap_bh);
	bitmap_bh = read_inode_bitmap(sb, i);
	if (!bitmap_bh)
	continue;

	x = ext3_count_free(bitmap_bh, EXT3_INODES_PER_GROUP(sb) / 8);
	printk("group %d: stored = %d, counted = %lu\n",
	i, le16_to_cpu(gdp->bg_free_inodes_count), x);
	bitmap_count += x;
	}
	brelse(bitmap_bh);
	printk("ext3_count_free_inodes: stored = %u, computed = %lu, %lu\n",
	le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
	return desc_count;
	#else
	desc_count = 0;
	for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
	gdp = ext3_get_group_desc (sb, i, NULL);
	if (!gdp)
	continue;
	desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
	cond_resched();
	}
	return desc_count;
	#endif
	}

	/* Called at mount-time, super-block is locked */
	unsigned long ext3_count_dirs (struct super_block * sb)
	{
	unsigned long count = 0;
	int i;

	for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
	struct ext3_group_desc *gdp = ext3_get_group_desc (sb, i, NULL);
	if (!gdp)
	continue;
	count += le16_to_cpu(gdp->bg_used_dirs_count);
	}
	return count;
	}