[linux.git] / fs / ext2 / ialloc.c

/*
 *  linux/fs/ext2/ialloc.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([email protected])
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  BSD ufs-inspired inode and directory allocation by 
 *  Stephen Tweedie ([email protected]), 1993
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller ([email protected]), 1995
 */

#include <linux/quotaops.h>
#include <linux/sched.h>
#include <linux/backing-dev.h>
#include <linux/buffer_head.h>
#include <linux/random.h>
#include "ext2.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 ext2_group_desc *desc;
	struct buffer_head *bh = NULL;

	desc = ext2_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)
		ext2_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;
}

static void ext2_release_inode(struct super_block *sb, int group, int dir)
{
	struct ext2_group_desc * desc;
	struct buffer_head *bh;

	desc = ext2_get_group_desc(sb, group, &bh);
	if (!desc) {
		ext2_error(sb, "ext2_release_inode",
			"can't get descriptor for group %d", group);
		return;
	}

	spin_lock(sb_bgl_lock(EXT2_SB(sb), group));
	le16_add_cpu(&desc->bg_free_inodes_count, 1);
	if (dir)
		le16_add_cpu(&desc->bg_used_dirs_count, -1);
	spin_unlock(sb_bgl_lock(EXT2_SB(sb), group));
	if (dir)
		percpu_counter_dec(&EXT2_SB(sb)->s_dirs_counter);
	mark_buffer_dirty(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 ext2_free_inode (struct inode * inode)
{
	struct super_block * sb = inode->i_sb;
	int is_directory;
	unsigned long ino;
	struct buffer_head *bitmap_bh;
	unsigned long block_group;
	unsigned long bit;
	struct ext2_super_block * es;

	ino = inode->i_ino;
	ext2_debug ("freeing inode %lu\n", ino);

	/*
	 * Note: we must free any quota before locking the superblock,
	 * as writing the quota to disk may need the lock as well.
	 */
	/* Quota is already initialized in iput() */
	dquot_free_inode(inode);
	dquot_drop(inode);

	es = EXT2_SB(sb)->s_es;
	is_directory = S_ISDIR(inode->i_mode);

	if (ino < EXT2_FIRST_INO(sb) ||
	    ino > le32_to_cpu(es->s_inodes_count)) {
		ext2_error (sb, "ext2_free_inode",
			    "reserved or nonexistent inode %lu", ino);
		return;
	}
	block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
	bit = (ino - 1) % EXT2_INODES_PER_GROUP(sb);
	bitmap_bh = read_inode_bitmap(sb, block_group);
	if (!bitmap_bh)
		return;

	/* Ok, now we can actually update the inode bitmaps.. */
	if (!ext2_clear_bit_atomic(sb_bgl_lock(EXT2_SB(sb), block_group),
				bit, (void *) bitmap_bh->b_data))
		ext2_error (sb, "ext2_free_inode",
			      "bit already cleared for inode %lu", ino);
	else
		ext2_release_inode(sb, block_group, is_directory);
	mark_buffer_dirty(bitmap_bh);
	if (sb->s_flags & MS_SYNCHRONOUS)
		sync_dirty_buffer(bitmap_bh);

	brelse(bitmap_bh);
}

/*
 * We perform asynchronous prereading of the new inode's inode block when
 * we create the inode, in the expectation that the inode will be written
 * back soon.  There are two reasons:
 *
 * - When creating a large number of files, the async prereads will be
 *   nicely merged into large reads
 * - When writing out a large number of inodes, we don't need to keep on
 *   stalling the writes while we read the inode block.
 *
 * FIXME: ext2_get_group_desc() needs to be simplified.
 */
static void ext2_preread_inode(struct inode *inode)
{
	unsigned long block_group;
	unsigned long offset;
	unsigned long block;
	struct ext2_group_desc * gdp;
	struct backing_dev_info *bdi;

	bdi = inode->i_mapping->backing_dev_info;
	if (bdi_read_congested(bdi))
		return;
	if (bdi_write_congested(bdi))
		return;

	block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
	gdp = ext2_get_group_desc(inode->i_sb, block_group, NULL);
	if (gdp == NULL)
		return;

	/*
	 * Figure out the offset within the block group inode table
	 */
	offset = ((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb)) *
				EXT2_INODE_SIZE(inode->i_sb);
	block = le32_to_cpu(gdp->bg_inode_table) +
				(offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));
	sb_breadahead(inode->i_sb, block);
}

/*
 * 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.
 */
static int find_group_dir(struct super_block *sb, struct inode *parent)
{
	int ngroups = EXT2_SB(sb)->s_groups_count;
	int avefreei = ext2_count_free_inodes(sb) / ngroups;
	struct ext2_group_desc *desc, *best_desc = NULL;
	int group, best_group = -1;

	for (group = 0; group < ngroups; group++) {
		desc = ext2_get_group_desc (sb, group, NULL);
		if (!desc || !desc->bg_free_inodes_count)
			continue;
		if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
			continue;
		if (!best_desc || 
		    (le16_to_cpu(desc->bg_free_blocks_count) >
		     le16_to_cpu(best_desc->bg_free_blocks_count))) {
			best_group = group;
			best_desc = desc;
		}
	}
	if (!best_desc)
		return -1;

	return best_group;
}

/* 
 * 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) or 
 * it's already running too large debt (max_debt). 
 * 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. 
 */ 

#define INODE_COST 64
#define BLOCK_COST 256

static int find_group_orlov(struct super_block *sb, struct inode *parent)
{
	int parent_group = EXT2_I(parent)->i_block_group;
	struct ext2_sb_info *sbi = EXT2_SB(sb);
	struct ext2_super_block *es = sbi->s_es;
	int ngroups = sbi->s_groups_count;
	int inodes_per_group = EXT2_INODES_PER_GROUP(sb);
	int freei;
	int avefreei;
	int free_blocks;
	int avefreeb;
	int blocks_per_dir;
	int ndirs;
	int max_debt, max_dirs, min_blocks, min_inodes;
	int group = -1, i;
	struct ext2_group_desc *desc;

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

	if ((parent == sb->s_root->d_inode) ||
	    (EXT2_I(parent)->i_flags & EXT2_TOPDIR_FL)) {
		struct ext2_group_desc *best_desc = NULL;
		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 = ext2_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);
			best_desc = desc;
		}
		if (best_group >= 0) {
			desc = best_desc;
			group = best_group;
			goto found;
		}
		goto fallback;
	}

	if (ndirs == 0)
		ndirs = 1;	/* percpu_counters are approximate... */

	blocks_per_dir = (le32_to_cpu(es->s_blocks_count)-free_blocks) / ndirs;

	max_dirs = ndirs / ngroups + inodes_per_group / 16;
	min_inodes = avefreei - inodes_per_group / 4;
	min_blocks = avefreeb - EXT2_BLOCKS_PER_GROUP(sb) / 4;

	max_debt = EXT2_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, BLOCK_COST);
	if (max_debt * INODE_COST > inodes_per_group)
		max_debt = inodes_per_group / INODE_COST;
	if (max_debt > 255)
		max_debt = 255;
	if (max_debt == 0)
		max_debt = 1;

	for (i = 0; i < ngroups; i++) {
		group = (parent_group + i) % ngroups;
		desc = ext2_get_group_desc (sb, group, NULL);
		if (!desc || !desc->bg_free_inodes_count)
			continue;
		if (sbi->s_debts[group] >= max_debt)
			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;
		goto found;
	}

fallback:
	for (i = 0; i < ngroups; i++) {
		group = (parent_group + i) % ngroups;
		desc = ext2_get_group_desc (sb, group, NULL);
		if (!desc || !desc->bg_free_inodes_count)
			continue;
		if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
			goto found;
	}

	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;

found:
	return group;
}

static int find_group_other(struct super_block *sb, struct inode *parent)
{
	int parent_group = EXT2_I(parent)->i_block_group;
	int ngroups = EXT2_SB(sb)->s_groups_count;
	struct ext2_group_desc *desc;
	int group, i;

	/*
	 * Try to place the inode in its parent directory
	 */
	group = parent_group;
	desc = ext2_get_group_desc (sb, group, NULL);
	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
			le16_to_cpu(desc->bg_free_blocks_count))
		goto found;

	/*
	 * 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 = ext2_get_group_desc (sb, group, NULL);
		if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
				le16_to_cpu(desc->bg_free_blocks_count))
			goto found;
	}

	/*
	 * 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 = ext2_get_group_desc (sb, group, NULL);
		if (desc && le16_to_cpu(desc->bg_free_inodes_count))
			goto found;
	}

	return -1;

found:
	return group;
}

struct inode *ext2_new_inode(struct inode *dir, umode_t mode,
			     const struct qstr *qstr)
{
	struct super_block *sb;
	struct buffer_head *bitmap_bh = NULL;
	struct buffer_head *bh2;
	int group, i;
	ino_t ino = 0;
	struct inode * inode;
	struct ext2_group_desc *gdp;
	struct ext2_super_block *es;
	struct ext2_inode_info *ei;
	struct ext2_sb_info *sbi;
	int err;

	sb = dir->i_sb;
	inode = new_inode(sb);
	if (!inode)
		return ERR_PTR(-ENOMEM);

	ei = EXT2_I(inode);
	sbi = EXT2_SB(sb);
	es = sbi->s_es;
	if (S_ISDIR(mode)) {
		if (test_opt(sb, OLDALLOC))
			group = find_group_dir(sb, dir);
		else
			group = find_group_orlov(sb, dir);
	} else 
		group = find_group_other(sb, dir);

	if (group == -1) {
		err = -ENOSPC;
		goto fail;
	}

	for (i = 0; i < sbi->s_groups_count; i++) {
		gdp = ext2_get_group_desc(sb, group, &bh2);
		brelse(bitmap_bh);
		bitmap_bh = read_inode_bitmap(sb, group);
		if (!bitmap_bh) {
			err = -EIO;
			goto fail;
		}
		ino = 0;

repeat_in_this_group:
		ino = ext2_find_next_zero_bit((unsigned long *)bitmap_bh->b_data,
					      EXT2_INODES_PER_GROUP(sb), ino);
		if (ino >= EXT2_INODES_PER_GROUP(sb)) {
			/*
			 * Rare race: find_group_xx() decided that there were
			 * free inodes in this group, but by the time we tried
			 * to allocate one, they're all gone.  This can also
			 * occur because the counters which find_group_orlov()
			 * uses are approximate.  So just go and search the
			 * next block group.
			 */
			if (++group == sbi->s_groups_count)
				group = 0;
			continue;
		}
		if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group),
						ino, bitmap_bh->b_data)) {
			/* we lost this inode */
			if (++ino >= EXT2_INODES_PER_GROUP(sb)) {
				/* this group is exhausted, try next group */
				if (++group == sbi->s_groups_count)
					group = 0;
				continue;
			}
			/* try to find free inode in the same group */
			goto repeat_in_this_group;
		}
		goto got;
	}

	/*
	 * Scanned all blockgroups.
	 */
	err = -ENOSPC;
	goto fail;
got:
	mark_buffer_dirty(bitmap_bh);
	if (sb->s_flags & MS_SYNCHRONOUS)
		sync_dirty_buffer(bitmap_bh);
	brelse(bitmap_bh);

	ino += group * EXT2_INODES_PER_GROUP(sb) + 1;
	if (ino < EXT2_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
		ext2_error (sb, "ext2_new_inode",
			    "reserved inode or inode > inodes count - "
			    "block_group = %d,inode=%lu", group,
			    (unsigned long) ino);
		err = -EIO;
		goto fail;
	}

	percpu_counter_add(&sbi->s_freeinodes_counter, -1);
	if (S_ISDIR(mode))
		percpu_counter_inc(&sbi->s_dirs_counter);

	spin_lock(sb_bgl_lock(sbi, group));
	le16_add_cpu(&gdp->bg_free_inodes_count, -1);
	if (S_ISDIR(mode)) {
		if (sbi->s_debts[group] < 255)
			sbi->s_debts[group]++;
		le16_add_cpu(&gdp->bg_used_dirs_count, 1);
	} else {
		if (sbi->s_debts[group])
			sbi->s_debts[group]--;
	}
	spin_unlock(sb_bgl_lock(sbi, group));

	mark_buffer_dirty(bh2);
	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;
	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_flags =
		ext2_mask_flags(mode, EXT2_I(dir)->i_flags & EXT2_FL_INHERITED);
	ei->i_faddr = 0;
	ei->i_frag_no = 0;
	ei->i_frag_size = 0;
	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;
	ei->i_dir_start_lookup = 0;
	ei->i_state = EXT2_STATE_NEW;
	ext2_set_inode_flags(inode);
	spin_lock(&sbi->s_next_gen_lock);
	inode->i_generation = sbi->s_next_generation++;
	spin_unlock(&sbi->s_next_gen_lock);
	if (insert_inode_locked(inode) < 0) {
		ext2_error(sb, "ext2_new_inode",
			   "inode number already in use - inode=%lu",
			   (unsigned long) ino);
		err = -EIO;
		goto fail;
	}

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

	err = ext2_init_acl(inode, dir);
	if (err)
		goto fail_free_drop;

	err = ext2_init_security(inode, dir, qstr);
	if (err)
		goto fail_free_drop;

	mark_inode_dirty(inode);
	ext2_debug("allocating inode %lu\n", inode->i_ino);
	ext2_preread_inode(inode);
	return inode;

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);
	return ERR_PTR(err);

fail:
	make_bad_inode(inode);
	iput(inode);
	return ERR_PTR(err);
}

unsigned long ext2_count_free_inodes (struct super_block * sb)
{
	struct ext2_group_desc *desc;
	unsigned long desc_count = 0;
	int i;	

#ifdef EXT2FS_DEBUG
	struct ext2_super_block *es;
	unsigned long bitmap_count = 0;
	struct buffer_head *bitmap_bh = NULL;

	es = EXT2_SB(sb)->s_es;
	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
		unsigned x;

		desc = ext2_get_group_desc (sb, i, NULL);
		if (!desc)
			continue;
		desc_count += le16_to_cpu(desc->bg_free_inodes_count);
		brelse(bitmap_bh);
		bitmap_bh = read_inode_bitmap(sb, i);
		if (!bitmap_bh)
			continue;

		x = ext2_count_free(bitmap_bh, EXT2_INODES_PER_GROUP(sb) / 8);
		printk("group %d: stored = %d, counted = %u\n",
			i, le16_to_cpu(desc->bg_free_inodes_count), x);
		bitmap_count += x;
	}
	brelse(bitmap_bh);
	printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
		(unsigned long)
		percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
		desc_count, bitmap_count);
	return desc_count;
#else
	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
		desc = ext2_get_group_desc (sb, i, NULL);
		if (!desc)
			continue;
		desc_count += le16_to_cpu(desc->bg_free_inodes_count);
	}
	return desc_count;
#endif
}

/* Called at mount-time, super-block is locked */
unsigned long ext2_count_dirs (struct super_block * sb)
{
	unsigned long count = 0;
	int i;

	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
		struct ext2_group_desc *gdp = ext2_get_group_desc (sb, i, NULL);
		if (!gdp)
			continue;
		count += le16_to_cpu(gdp->bg_used_dirs_count);
	}
	return count;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/ext2/ialloc.c
	3	*
	4	* Copyright (C) 1992, 1993, 1994, 1995
	5	* Remy Card ([email protected])
	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 ([email protected]), 1993
	11	* Big-endian to little-endian byte-swapping/bitmaps by
	12	* David S. Miller ([email protected]), 1995
	13	*/
	14
1da177e4 LT	15	#include <linux/quotaops.h>
	16	#include <linux/sched.h>
	17	#include <linux/backing-dev.h>
	18	#include <linux/buffer_head.h>
	19	#include <linux/random.h>
	20	#include "ext2.h"
	21	#include "xattr.h"
	22	#include "acl.h"
	23
	24	/*
	25	* ialloc.c contains the inodes allocation and deallocation routines
	26	*/
	27
	28	/*
	29	* The free inodes are managed by bitmaps. A file system contains several
	30	* blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
	31	* block for inodes, N blocks for the inode table and data blocks.
	32	*
	33	* The file system contains group descriptors which are located after the
	34	* super block. Each descriptor contains the number of the bitmap block and
	35	* the free blocks count in the block.
	36	*/
	37
	38
	39	/*
	40	* Read the inode allocation bitmap for a given block_group, reading
	41	* into the specified slot in the superblock's bitmap cache.
	42	*
	43	* Return buffer_head of bitmap on success or NULL.
	44	*/
	45	static struct buffer_head *
	46	read_inode_bitmap(struct super_block * sb, unsigned long block_group)
	47	{
	48	struct ext2_group_desc *desc;
	49	struct buffer_head *bh = NULL;
	50
	51	desc = ext2_get_group_desc(sb, block_group, NULL);
	52	if (!desc)
	53	goto error_out;
	54
	55	bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
	56	if (!bh)
	57	ext2_error(sb, "read_inode_bitmap",
	58	"Cannot read inode bitmap - "
	59	"block_group = %lu, inode_bitmap = %u",
	60	block_group, le32_to_cpu(desc->bg_inode_bitmap));
	61	error_out:
	62	return bh;
	63	}
	64
	65	static void ext2_release_inode(struct super_block *sb, int group, int dir)
	66	{
	67	struct ext2_group_desc * desc;
	68	struct buffer_head *bh;
	69
	70	desc = ext2_get_group_desc(sb, group, &bh);
	71	if (!desc) {
	72	ext2_error(sb, "ext2_release_inode",
	73	"can't get descriptor for group %d", group);
	74	return;
	75	}
	76
	77	spin_lock(sb_bgl_lock(EXT2_SB(sb), group));
fba4d399	78	le16_add_cpu(&desc->bg_free_inodes_count, 1);
1da177e4	79	if (dir)
fba4d399	80	le16_add_cpu(&desc->bg_used_dirs_count, -1);
1da177e4 LT	81	spin_unlock(sb_bgl_lock(EXT2_SB(sb), group));
	82	if (dir)
	83	percpu_counter_dec(&EXT2_SB(sb)->s_dirs_counter);
1da177e4 LT	84	mark_buffer_dirty(bh);
	85	}
	86
	87	/*
	88	* NOTE! When we get the inode, we're the only people
	89	* that have access to it, and as such there are no
	90	* race conditions we have to worry about. The inode
	91	* is not on the hash-lists, and it cannot be reached
	92	* through the filesystem because the directory entry
	93	* has been deleted earlier.
	94	*
	95	* HOWEVER: we must make sure that we get no aliases,
	96	* which means that we have to call "clear_inode()"
	97	* _before_ we mark the inode not in use in the inode
	98	* bitmaps. Otherwise a newly created file might use
	99	* the same inode number (not actually the same pointer
	100	* though), and then we'd have two inodes sharing the
	101	* same inode number and space on the harddisk.
	102	*/
	103	void ext2_free_inode (struct inode * inode)
	104	{
	105	struct super_block * sb = inode->i_sb;
	106	int is_directory;
	107	unsigned long ino;
524e4a1d	108	struct buffer_head *bitmap_bh;
1da177e4 LT	109	unsigned long block_group;
	110	unsigned long bit;
	111	struct ext2_super_block * es;
	112
	113	ino = inode->i_ino;
	114	ext2_debug ("freeing inode %lu\n", ino);
	115
	116	/*
	117	* Note: we must free any quota before locking the superblock,
	118	* as writing the quota to disk may need the lock as well.
	119	*/
72edc4d0	120	/* Quota is already initialized in iput() */
72edc4d0 AV	121	dquot_free_inode(inode);
72edc4d0 AV	122	dquot_drop(inode);
1da177e4 LT	123
	124	es = EXT2_SB(sb)->s_es;
	125	is_directory = S_ISDIR(inode->i_mode);
	126
1da177e4 LT	127	if (ino < EXT2_FIRST_INO(sb) \|\|
	128	ino > le32_to_cpu(es->s_inodes_count)) {
	129	ext2_error (sb, "ext2_free_inode",
	130	"reserved or nonexistent inode %lu", ino);
524e4a1d	131	return;
1da177e4 LT	132	}
	133	block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
	134	bit = (ino - 1) % EXT2_INODES_PER_GROUP(sb);
1da177e4 LT	135	bitmap_bh = read_inode_bitmap(sb, block_group);
1da177e4 LT	136	if (!bitmap_bh)
524e4a1d	137	return;
1da177e4 LT	138
	139	/* Ok, now we can actually update the inode bitmaps.. */
	140	if (!ext2_clear_bit_atomic(sb_bgl_lock(EXT2_SB(sb), block_group),
	141	bit, (void *) bitmap_bh->b_data))
	142	ext2_error (sb, "ext2_free_inode",
	143	"bit already cleared for inode %lu", ino);
	144	else
	145	ext2_release_inode(sb, block_group, is_directory);
	146	mark_buffer_dirty(bitmap_bh);
	147	if (sb->s_flags & MS_SYNCHRONOUS)
	148	sync_dirty_buffer(bitmap_bh);
524e4a1d	149
1da177e4 LT	150	brelse(bitmap_bh);
	151	}
	152
	153	/*
	154	* We perform asynchronous prereading of the new inode's inode block when
	155	* we create the inode, in the expectation that the inode will be written
	156	* back soon. There are two reasons:
	157	*
	158	* - When creating a large number of files, the async prereads will be
	159	* nicely merged into large reads
	160	* - When writing out a large number of inodes, we don't need to keep on
	161	* stalling the writes while we read the inode block.
	162	*
	163	* FIXME: ext2_get_group_desc() needs to be simplified.
	164	*/
	165	static void ext2_preread_inode(struct inode *inode)
	166	{
	167	unsigned long block_group;
	168	unsigned long offset;
	169	unsigned long block;
1da177e4 LT	170	struct ext2_group_desc * gdp;
	171	struct backing_dev_info *bdi;
	172
	173	bdi = inode->i_mapping->backing_dev_info;
	174	if (bdi_read_congested(bdi))
	175	return;
	176	if (bdi_write_congested(bdi))
	177	return;
	178
	179	block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
ef2fb679	180	gdp = ext2_get_group_desc(inode->i_sb, block_group, NULL);
1da177e4 LT	181	if (gdp == NULL)
	182	return;
	183
	184	/*
	185	* Figure out the offset within the block group inode table
	186	*/
	187	offset = ((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb)) *
	188	EXT2_INODE_SIZE(inode->i_sb);
	189	block = le32_to_cpu(gdp->bg_inode_table) +
	190	(offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));
	191	sb_breadahead(inode->i_sb, block);
	192	}
	193
	194	/*
	195	* There are two policies for allocating an inode. If the new inode is
	196	* a directory, then a forward search is made for a block group with both
	197	* free space and a low directory-to-inode ratio; if that fails, then of
	198	* the groups with above-average free space, that group with the fewest
	199	* directories already is chosen.
	200	*
	201	* For other inodes, search forward from the parent directory\'s block
	202	* group to find a free inode.
	203	*/
	204	static int find_group_dir(struct super_block sb, struct inode parent)
	205	{
	206	int ngroups = EXT2_SB(sb)->s_groups_count;
	207	int avefreei = ext2_count_free_inodes(sb) / ngroups;
	208	struct ext2_group_desc desc, best_desc = NULL;
1da177e4 LT	209	int group, best_group = -1;
	210
	211	for (group = 0; group < ngroups; group++) {
ef2fb679	212	desc = ext2_get_group_desc (sb, group, NULL);
1da177e4 LT	213	if (!desc \|\| !desc->bg_free_inodes_count)
	214	continue;
	215	if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
	216	continue;
	217	if (!best_desc \|\|
	218	(le16_to_cpu(desc->bg_free_blocks_count) >
	219	le16_to_cpu(best_desc->bg_free_blocks_count))) {
	220	best_group = group;
	221	best_desc = desc;
1da177e4 LT	222	}
	223	}
	224	if (!best_desc)
	225	return -1;
	226
	227	return best_group;
	228	}
	229
	230	/*
	231	* Orlov's allocator for directories.
	232	*
	233	* We always try to spread first-level directories.
	234	*
	235	* If there are blockgroups with both free inodes and free blocks counts
	236	* not worse than average we return one with smallest directory count.
	237	* Otherwise we simply return a random group.
	238	*
	239	* For the rest rules look so:
	240	*
	241	* It's OK to put directory into a group unless
	242	* it has too many directories already (max_dirs) or
	243	* it has too few free inodes left (min_inodes) or
	244	* it has too few free blocks left (min_blocks) or
	245	* it's already running too large debt (max_debt).
1cc8dcf5	246	* Parent's group is preferred, if it doesn't satisfy these
1da177e4 LT	247	* conditions we search cyclically through the rest. If none
	248	* of the groups look good we just look for a group with more
	249	* free inodes than average (starting at parent's group).
	250	*
	251	* Debt is incremented each time we allocate a directory and decremented
	252	* when we allocate an inode, within 0--255.
	253	*/
	254
	255	#define INODE_COST 64
	256	#define BLOCK_COST 256
	257
	258	static int find_group_orlov(struct super_block sb, struct inode parent)
	259	{
	260	int parent_group = EXT2_I(parent)->i_block_group;
	261	struct ext2_sb_info *sbi = EXT2_SB(sb);
	262	struct ext2_super_block *es = sbi->s_es;
	263	int ngroups = sbi->s_groups_count;
	264	int inodes_per_group = EXT2_INODES_PER_GROUP(sb);
	265	int freei;
	266	int avefreei;
	267	int free_blocks;
	268	int avefreeb;
	269	int blocks_per_dir;
	270	int ndirs;
	271	int max_debt, max_dirs, min_blocks, min_inodes;
	272	int group = -1, i;
	273	struct ext2_group_desc *desc;
1da177e4 LT	274
	275	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
	276	avefreei = freei / ngroups;
	277	free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
	278	avefreeb = free_blocks / ngroups;
	279	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
	280
	281	if ((parent == sb->s_root->d_inode) \|\|
	282	(EXT2_I(parent)->i_flags & EXT2_TOPDIR_FL)) {
	283	struct ext2_group_desc *best_desc = NULL;
1da177e4 LT	284	int best_ndir = inodes_per_group;
	285	int best_group = -1;
	286
	287	get_random_bytes(&group, sizeof(group));
	288	parent_group = (unsigned)group % ngroups;
	289	for (i = 0; i < ngroups; i++) {
	290	group = (parent_group + i) % ngroups;
ef2fb679	291	desc = ext2_get_group_desc (sb, group, NULL);
1da177e4 LT	292	if (!desc \|\| !desc->bg_free_inodes_count)
	293	continue;
	294	if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
	295	continue;
	296	if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
	297	continue;
	298	if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
	299	continue;
	300	best_group = group;
	301	best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
	302	best_desc = desc;
1da177e4 LT	303	}
	304	if (best_group >= 0) {
	305	desc = best_desc;
1da177e4 LT	306	group = best_group;
	307	goto found;
	308	}
	309	goto fallback;
	310	}
	311
	312	if (ndirs == 0)
	313	ndirs = 1; /* percpu_counters are approximate... */
	314
	315	blocks_per_dir = (le32_to_cpu(es->s_blocks_count)-free_blocks) / ndirs;
	316
	317	max_dirs = ndirs / ngroups + inodes_per_group / 16;
	318	min_inodes = avefreei - inodes_per_group / 4;
	319	min_blocks = avefreeb - EXT2_BLOCKS_PER_GROUP(sb) / 4;
	320
	321	max_debt = EXT2_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, BLOCK_COST);
	322	if (max_debt * INODE_COST > inodes_per_group)
	323	max_debt = inodes_per_group / INODE_COST;
	324	if (max_debt > 255)
	325	max_debt = 255;
	326	if (max_debt == 0)
	327	max_debt = 1;
	328
	329	for (i = 0; i < ngroups; i++) {
	330	group = (parent_group + i) % ngroups;
ef2fb679	331	desc = ext2_get_group_desc (sb, group, NULL);
1da177e4 LT	332	if (!desc \|\| !desc->bg_free_inodes_count)
	333	continue;
	334	if (sbi->s_debts[group] >= max_debt)
	335	continue;
	336	if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
	337	continue;
	338	if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
	339	continue;
	340	if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
	341	continue;
	342	goto found;
	343	}
	344
	345	fallback:
	346	for (i = 0; i < ngroups; i++) {
	347	group = (parent_group + i) % ngroups;
ef2fb679	348	desc = ext2_get_group_desc (sb, group, NULL);
1da177e4 LT	349	if (!desc \|\| !desc->bg_free_inodes_count)
	350	continue;
	351	if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
	352	goto found;
	353	}
	354
	355	if (avefreei) {
	356	/*
	357	* The free-inodes counter is approximate, and for really small
	358	* filesystems the above test can fail to find any blockgroups
	359	*/
	360	avefreei = 0;
	361	goto fallback;
	362	}
	363
	364	return -1;
	365
	366	found:
	367	return group;
	368	}
	369
	370	static int find_group_other(struct super_block sb, struct inode parent)
	371	{
	372	int parent_group = EXT2_I(parent)->i_block_group;
	373	int ngroups = EXT2_SB(sb)->s_groups_count;
	374	struct ext2_group_desc *desc;
1da177e4 LT	375	int group, i;
	376
	377	/*
	378	* Try to place the inode in its parent directory
	379	*/
	380	group = parent_group;
ef2fb679	381	desc = ext2_get_group_desc (sb, group, NULL);
1da177e4 LT	382	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
	383	le16_to_cpu(desc->bg_free_blocks_count))
	384	goto found;
	385
	386	/*
	387	* We're going to place this inode in a different blockgroup from its
	388	* parent. We want to cause files in a common directory to all land in
	389	* the same blockgroup. But we want files which are in a different
	390	* directory which shares a blockgroup with our parent to land in a
	391	* different blockgroup.
	392	*
	393	* So add our directory's i_ino into the starting point for the hash.
	394	*/
	395	group = (group + parent->i_ino) % ngroups;
	396
	397	/*
	398	* Use a quadratic hash to find a group with a free inode and some
	399	* free blocks.
	400	*/
	401	for (i = 1; i < ngroups; i <<= 1) {
	402	group += i;
	403	if (group >= ngroups)
	404	group -= ngroups;
ef2fb679	405	desc = ext2_get_group_desc (sb, group, NULL);
1da177e4 LT	406	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
	407	le16_to_cpu(desc->bg_free_blocks_count))
	408	goto found;
	409	}
	410
	411	/*
	412	* That failed: try linear search for a free inode, even if that group
	413	* has no free blocks.
	414	*/
	415	group = parent_group;
	416	for (i = 0; i < ngroups; i++) {
	417	if (++group >= ngroups)
	418	group = 0;
ef2fb679	419	desc = ext2_get_group_desc (sb, group, NULL);
1da177e4 LT	420	if (desc && le16_to_cpu(desc->bg_free_inodes_count))
	421	goto found;
	422	}
	423
	424	return -1;
	425
	426	found:
	427	return group;
	428	}
	429
3ea40bc9	430	struct inode ext2_new_inode(struct inode dir, umode_t mode,
2a7dba39	431	const struct qstr *qstr)
1da177e4 LT	432	{
	433	struct super_block *sb;
	434	struct buffer_head *bitmap_bh = NULL;
	435	struct buffer_head *bh2;
	436	int group, i;
	437	ino_t ino = 0;
	438	struct inode * inode;
	439	struct ext2_group_desc *gdp;
	440	struct ext2_super_block *es;
	441	struct ext2_inode_info *ei;
	442	struct ext2_sb_info *sbi;
	443	int err;
	444
	445	sb = dir->i_sb;
	446	inode = new_inode(sb);
	447	if (!inode)
	448	return ERR_PTR(-ENOMEM);
	449
	450	ei = EXT2_I(inode);
	451	sbi = EXT2_SB(sb);
	452	es = sbi->s_es;
	453	if (S_ISDIR(mode)) {
	454	if (test_opt(sb, OLDALLOC))
	455	group = find_group_dir(sb, dir);
	456	else
	457	group = find_group_orlov(sb, dir);
	458	} else
	459	group = find_group_other(sb, dir);
	460
	461	if (group == -1) {
	462	err = -ENOSPC;
	463	goto fail;
	464	}
	465
	466	for (i = 0; i < sbi->s_groups_count; i++) {
	467	gdp = ext2_get_group_desc(sb, group, &bh2);
	468	brelse(bitmap_bh);
	469	bitmap_bh = read_inode_bitmap(sb, group);
	470	if (!bitmap_bh) {
	471	err = -EIO;
	472	goto fail;
	473	}
	474	ino = 0;
	475
	476	repeat_in_this_group:
	477	ino = ext2_find_next_zero_bit((unsigned long *)bitmap_bh->b_data,
	478	EXT2_INODES_PER_GROUP(sb), ino);
	479	if (ino >= EXT2_INODES_PER_GROUP(sb)) {
	480	/*
	481	* Rare race: find_group_xx() decided that there were
	482	* free inodes in this group, but by the time we tried
	483	* to allocate one, they're all gone. This can also
	484	* occur because the counters which find_group_orlov()
	485	* uses are approximate. So just go and search the
	486	* next block group.
	487	*/
	488	if (++group == sbi->s_groups_count)
	489	group = 0;
	490	continue;
	491	}
	492	if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group),
	493	ino, bitmap_bh->b_data)) {
	494	/* we lost this inode */
	495	if (++ino >= EXT2_INODES_PER_GROUP(sb)) {
496	/* this group is exhausted, try next group */
497	if (++group == sbi->s_groups_count)
498	group = 0;
499	continue;
500	}
501	/* try to find free inode in the same group */
502	goto repeat_in_this_group;
503	}
504	goto got;
505	}
506
507	/*
508	* Scanned all blockgroups.
509	*/
510	err = -ENOSPC;
511	goto fail;
512	got:
513	mark_buffer_dirty(bitmap_bh);
514	if (sb->s_flags & MS_SYNCHRONOUS)
515	sync_dirty_buffer(bitmap_bh);
516	brelse(bitmap_bh);
517
518	ino += group * EXT2_INODES_PER_GROUP(sb) + 1;
519	if (ino < EXT2_FIRST_INO(sb) \|\| ino > le32_to_cpu(es->s_inodes_count)) {
520	ext2_error (sb, "ext2_new_inode",
521	"reserved inode or inode > inodes count - "
522	"block_group = %d,inode=%lu", group,
523	(unsigned long) ino);
524	err = -EIO;
525	goto fail;
526	}
527
aa0dff2d	528	percpu_counter_add(&sbi->s_freeinodes_counter, -1);
1da177e4 LT	529	if (S_ISDIR(mode))
	530	percpu_counter_inc(&sbi->s_dirs_counter);
	531
	532	spin_lock(sb_bgl_lock(sbi, group));
fba4d399	533	le16_add_cpu(&gdp->bg_free_inodes_count, -1);
1da177e4 LT	534	if (S_ISDIR(mode)) {
	535	if (sbi->s_debts[group] < 255)
	536	sbi->s_debts[group]++;
fba4d399	537	le16_add_cpu(&gdp->bg_used_dirs_count, 1);
1da177e4 LT	538	} else {
	539	if (sbi->s_debts[group])
	540	sbi->s_debts[group]--;
	541	}
	542	spin_unlock(sb_bgl_lock(sbi, group));
	543
1da177e4	544	mark_buffer_dirty(bh2);
ffba102d DM	545	if (test_opt(sb, GRPID)) {
	546	inode->i_mode = mode;
	547	inode->i_uid = current_fsuid();
1da177e4	548	inode->i_gid = dir->i_gid;
1da177e4	549	} else
ffba102d	550	inode_init_owner(inode, dir, mode);
1da177e4 LT	551
1da177e4 LT	552	inode->i_ino = ino;
1da177e4 LT	553	inode->i_blocks = 0;
	554	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
	555	memset(ei->i_data, 0, sizeof(ei->i_data));
ef8b6461 DG	556	ei->i_flags =
ef8b6461 DG	557	ext2_mask_flags(mode, EXT2_I(dir)->i_flags & EXT2_FL_INHERITED);
1da177e4 LT	558	ei->i_faddr = 0;
	559	ei->i_frag_no = 0;
	560	ei->i_frag_size = 0;
	561	ei->i_file_acl = 0;
	562	ei->i_dir_acl = 0;
	563	ei->i_dtime = 0;
a686cd89	564	ei->i_block_alloc_info = NULL;
1da177e4	565	ei->i_block_group = group;
1da177e4 LT	566	ei->i_dir_start_lookup = 0;
	567	ei->i_state = EXT2_STATE_NEW;
	568	ext2_set_inode_flags(inode);
	569	spin_lock(&sbi->s_next_gen_lock);
	570	inode->i_generation = sbi->s_next_generation++;
	571	spin_unlock(&sbi->s_next_gen_lock);
41080b5a	572	if (insert_inode_locked(inode) < 0) {
ef6919c2 JK	573	ext2_error(sb, "ext2_new_inode",
	574	"inode number already in use - inode=%lu",
	575	(unsigned long) ino);
	576	err = -EIO;
	577	goto fail;
41080b5a	578	}
1da177e4	579
871a2931	580	dquot_initialize(inode);
63936dda CH	581	err = dquot_alloc_inode(inode);
63936dda CH	582	if (err)
9ed6c2fb	583	goto fail_drop;
9ed6c2fb	584
1da177e4	585	err = ext2_init_acl(inode, dir);
9ed6c2fb CS	586	if (err)
	587	goto fail_free_drop;
	588
2a7dba39	589	err = ext2_init_security(inode, dir, qstr);
9ed6c2fb CS	590	if (err)
	591	goto fail_free_drop;
	592
1da177e4 LT	593	mark_inode_dirty(inode);
	594	ext2_debug("allocating inode %lu\n", inode->i_ino);
	595	ext2_preread_inode(inode);
	596	return inode;
	597
9ed6c2fb	598	fail_free_drop:
63936dda	599	dquot_free_inode(inode);
9ed6c2fb CS	600
9ed6c2fb CS	601	fail_drop:
9f754758	602	dquot_drop(inode);
1da177e4	603	inode->i_flags \|= S_NOQUOTA;
6d6b77f1	604	clear_nlink(inode);
41080b5a	605	unlock_new_inode(inode);
1da177e4 LT	606	iput(inode);
	607	return ERR_PTR(err);
	608
	609	fail:
	610	make_bad_inode(inode);
	611	iput(inode);
	612	return ERR_PTR(err);
	613	}
	614
	615	unsigned long ext2_count_free_inodes (struct super_block * sb)
	616	{
	617	struct ext2_group_desc *desc;
	618	unsigned long desc_count = 0;
	619	int i;
	620
	621	#ifdef EXT2FS_DEBUG
	622	struct ext2_super_block *es;
	623	unsigned long bitmap_count = 0;
	624	struct buffer_head *bitmap_bh = NULL;
	625
1da177e4 LT	626	es = EXT2_SB(sb)->s_es;
	627	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
	628	unsigned x;
	629
	630	desc = ext2_get_group_desc (sb, i, NULL);
	631	if (!desc)
	632	continue;
	633	desc_count += le16_to_cpu(desc->bg_free_inodes_count);
	634	brelse(bitmap_bh);
	635	bitmap_bh = read_inode_bitmap(sb, i);
	636	if (!bitmap_bh)
	637	continue;
	638
	639	x = ext2_count_free(bitmap_bh, EXT2_INODES_PER_GROUP(sb) / 8);
	640	printk("group %d: stored = %d, counted = %u\n",
	641	i, le16_to_cpu(desc->bg_free_inodes_count), x);
	642	bitmap_count += x;
	643	}
	644	brelse(bitmap_bh);
	645	printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
ecd0afa3	646	(unsigned long)
1da177e4 LT	647	percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
1da177e4 LT	648	desc_count, bitmap_count);
1da177e4 LT	649	return desc_count;
	650	#else
	651	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
	652	desc = ext2_get_group_desc (sb, i, NULL);
	653	if (!desc)
	654	continue;
	655	desc_count += le16_to_cpu(desc->bg_free_inodes_count);
	656	}
	657	return desc_count;
	658	#endif
	659	}
	660
	661	/* Called at mount-time, super-block is locked */
	662	unsigned long ext2_count_dirs (struct super_block * sb)
	663	{
	664	unsigned long count = 0;
	665	int i;
	666
	667	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
	668	struct ext2_group_desc *gdp = ext2_get_group_desc (sb, i, NULL);
	669	if (!gdp)
	670	continue;
	671	count += le16_to_cpu(gdp->bg_used_dirs_count);
	672	}
	673	return count;
	674	}
	675