xref: /openbmc/linux/fs/ext2/ialloc.c (revision a251c17a)
1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   *  linux/fs/ext2/ialloc.c
4   *
5   * Copyright (C) 1992, 1993, 1994, 1995
6   * Remy Card (card@masi.ibp.fr)
7   * Laboratoire MASI - Institut Blaise Pascal
8   * Universite Pierre et Marie Curie (Paris VI)
9   *
10   *  BSD ufs-inspired inode and directory allocation by
11   *  Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
12   *  Big-endian to little-endian byte-swapping/bitmaps by
13   *        David S. Miller (davem@caip.rutgers.edu), 1995
14   */
15  
16  #include <linux/quotaops.h>
17  #include <linux/sched.h>
18  #include <linux/backing-dev.h>
19  #include <linux/buffer_head.h>
20  #include <linux/random.h>
21  #include "ext2.h"
22  #include "xattr.h"
23  #include "acl.h"
24  
25  /*
26   * ialloc.c contains the inodes allocation and deallocation routines
27   */
28  
29  /*
30   * The free inodes are managed by bitmaps.  A file system contains several
31   * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
32   * block for inodes, N blocks for the inode table and data blocks.
33   *
34   * The file system contains group descriptors which are located after the
35   * super block.  Each descriptor contains the number of the bitmap block and
36   * the free blocks count in the block.
37   */
38  
39  
40  /*
41   * Read the inode allocation bitmap for a given block_group, reading
42   * into the specified slot in the superblock's bitmap cache.
43   *
44   * Return buffer_head of bitmap on success or NULL.
45   */
46  static struct buffer_head *
47  read_inode_bitmap(struct super_block * sb, unsigned long block_group)
48  {
49  	struct ext2_group_desc *desc;
50  	struct buffer_head *bh = NULL;
51  
52  	desc = ext2_get_group_desc(sb, block_group, NULL);
53  	if (!desc)
54  		goto error_out;
55  
56  	bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
57  	if (!bh)
58  		ext2_error(sb, "read_inode_bitmap",
59  			    "Cannot read inode bitmap - "
60  			    "block_group = %lu, inode_bitmap = %u",
61  			    block_group, le32_to_cpu(desc->bg_inode_bitmap));
62  error_out:
63  	return bh;
64  }
65  
66  static void ext2_release_inode(struct super_block *sb, int group, int dir)
67  {
68  	struct ext2_group_desc * desc;
69  	struct buffer_head *bh;
70  
71  	desc = ext2_get_group_desc(sb, group, &bh);
72  	if (!desc) {
73  		ext2_error(sb, "ext2_release_inode",
74  			"can't get descriptor for group %d", group);
75  		return;
76  	}
77  
78  	spin_lock(sb_bgl_lock(EXT2_SB(sb), group));
79  	le16_add_cpu(&desc->bg_free_inodes_count, 1);
80  	if (dir)
81  		le16_add_cpu(&desc->bg_used_dirs_count, -1);
82  	spin_unlock(sb_bgl_lock(EXT2_SB(sb), group));
83  	percpu_counter_inc(&EXT2_SB(sb)->s_freeinodes_counter);
84  	if (dir)
85  		percpu_counter_dec(&EXT2_SB(sb)->s_dirs_counter);
86  	mark_buffer_dirty(bh);
87  }
88  
89  /*
90   * NOTE! When we get the inode, we're the only people
91   * that have access to it, and as such there are no
92   * race conditions we have to worry about. The inode
93   * is not on the hash-lists, and it cannot be reached
94   * through the filesystem because the directory entry
95   * has been deleted earlier.
96   *
97   * HOWEVER: we must make sure that we get no aliases,
98   * which means that we have to call "clear_inode()"
99   * _before_ we mark the inode not in use in the inode
100   * bitmaps. Otherwise a newly created file might use
101   * the same inode number (not actually the same pointer
102   * though), and then we'd have two inodes sharing the
103   * same inode number and space on the harddisk.
104   */
105  void ext2_free_inode (struct inode * inode)
106  {
107  	struct super_block * sb = inode->i_sb;
108  	int is_directory;
109  	unsigned long ino;
110  	struct buffer_head *bitmap_bh;
111  	unsigned long block_group;
112  	unsigned long bit;
113  	struct ext2_super_block * es;
114  
115  	ino = inode->i_ino;
116  	ext2_debug ("freeing inode %lu\n", ino);
117  
118  	/*
119  	 * Note: we must free any quota before locking the superblock,
120  	 * as writing the quota to disk may need the lock as well.
121  	 */
122  	/* Quota is already initialized in iput() */
123  	dquot_free_inode(inode);
124  	dquot_drop(inode);
125  
126  	es = EXT2_SB(sb)->s_es;
127  	is_directory = S_ISDIR(inode->i_mode);
128  
129  	if (ino < EXT2_FIRST_INO(sb) ||
130  	    ino > le32_to_cpu(es->s_inodes_count)) {
131  		ext2_error (sb, "ext2_free_inode",
132  			    "reserved or nonexistent inode %lu", ino);
133  		return;
134  	}
135  	block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
136  	bit = (ino - 1) % EXT2_INODES_PER_GROUP(sb);
137  	bitmap_bh = read_inode_bitmap(sb, block_group);
138  	if (!bitmap_bh)
139  		return;
140  
141  	/* Ok, now we can actually update the inode bitmaps.. */
142  	if (!ext2_clear_bit_atomic(sb_bgl_lock(EXT2_SB(sb), block_group),
143  				bit, (void *) bitmap_bh->b_data))
144  		ext2_error (sb, "ext2_free_inode",
145  			      "bit already cleared for inode %lu", ino);
146  	else
147  		ext2_release_inode(sb, block_group, is_directory);
148  	mark_buffer_dirty(bitmap_bh);
149  	if (sb->s_flags & SB_SYNCHRONOUS)
150  		sync_dirty_buffer(bitmap_bh);
151  
152  	brelse(bitmap_bh);
153  }
154  
155  /*
156   * We perform asynchronous prereading of the new inode's inode block when
157   * we create the inode, in the expectation that the inode will be written
158   * back soon.  There are two reasons:
159   *
160   * - When creating a large number of files, the async prereads will be
161   *   nicely merged into large reads
162   * - When writing out a large number of inodes, we don't need to keep on
163   *   stalling the writes while we read the inode block.
164   *
165   * FIXME: ext2_get_group_desc() needs to be simplified.
166   */
167  static void ext2_preread_inode(struct inode *inode)
168  {
169  	unsigned long block_group;
170  	unsigned long offset;
171  	unsigned long block;
172  	struct ext2_group_desc * gdp;
173  
174  	block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
175  	gdp = ext2_get_group_desc(inode->i_sb, block_group, NULL);
176  	if (gdp == NULL)
177  		return;
178  
179  	/*
180  	 * Figure out the offset within the block group inode table
181  	 */
182  	offset = ((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb)) *
183  				EXT2_INODE_SIZE(inode->i_sb);
184  	block = le32_to_cpu(gdp->bg_inode_table) +
185  				(offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));
186  	sb_breadahead(inode->i_sb, block);
187  }
188  
189  /*
190   * There are two policies for allocating an inode.  If the new inode is
191   * a directory, then a forward search is made for a block group with both
192   * free space and a low directory-to-inode ratio; if that fails, then of
193   * the groups with above-average free space, that group with the fewest
194   * directories already is chosen.
195   *
196   * For other inodes, search forward from the parent directory\'s block
197   * group to find a free inode.
198   */
199  static int find_group_dir(struct super_block *sb, struct inode *parent)
200  {
201  	int ngroups = EXT2_SB(sb)->s_groups_count;
202  	int avefreei = ext2_count_free_inodes(sb) / ngroups;
203  	struct ext2_group_desc *desc, *best_desc = NULL;
204  	int group, best_group = -1;
205  
206  	for (group = 0; group < ngroups; group++) {
207  		desc = ext2_get_group_desc (sb, group, NULL);
208  		if (!desc || !desc->bg_free_inodes_count)
209  			continue;
210  		if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
211  			continue;
212  		if (!best_desc ||
213  		    (le16_to_cpu(desc->bg_free_blocks_count) >
214  		     le16_to_cpu(best_desc->bg_free_blocks_count))) {
215  			best_group = group;
216  			best_desc = desc;
217  		}
218  	}
219  
220  	return best_group;
221  }
222  
223  /*
224   * Orlov's allocator for directories.
225   *
226   * We always try to spread first-level directories.
227   *
228   * If there are blockgroups with both free inodes and free blocks counts
229   * not worse than average we return one with smallest directory count.
230   * Otherwise we simply return a random group.
231   *
232   * For the rest rules look so:
233   *
234   * It's OK to put directory into a group unless
235   * it has too many directories already (max_dirs) or
236   * it has too few free inodes left (min_inodes) or
237   * it has too few free blocks left (min_blocks) or
238   * it's already running too large debt (max_debt).
239   * Parent's group is preferred, if it doesn't satisfy these
240   * conditions we search cyclically through the rest. If none
241   * of the groups look good we just look for a group with more
242   * free inodes than average (starting at parent's group).
243   *
244   * Debt is incremented each time we allocate a directory and decremented
245   * when we allocate an inode, within 0--255.
246   */
247  
248  #define INODE_COST 64
249  #define BLOCK_COST 256
250  
251  static int find_group_orlov(struct super_block *sb, struct inode *parent)
252  {
253  	int parent_group = EXT2_I(parent)->i_block_group;
254  	struct ext2_sb_info *sbi = EXT2_SB(sb);
255  	struct ext2_super_block *es = sbi->s_es;
256  	int ngroups = sbi->s_groups_count;
257  	int inodes_per_group = EXT2_INODES_PER_GROUP(sb);
258  	int freei;
259  	int avefreei;
260  	int free_blocks;
261  	int avefreeb;
262  	int blocks_per_dir;
263  	int ndirs;
264  	int max_debt, max_dirs, min_blocks, min_inodes;
265  	int group = -1, i;
266  	struct ext2_group_desc *desc;
267  
268  	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
269  	avefreei = freei / ngroups;
270  	free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
271  	avefreeb = free_blocks / ngroups;
272  	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
273  
274  	if ((parent == d_inode(sb->s_root)) ||
275  	    (EXT2_I(parent)->i_flags & EXT2_TOPDIR_FL)) {
276  		struct ext2_group_desc *best_desc = NULL;
277  		int best_ndir = inodes_per_group;
278  		int best_group = -1;
279  
280  		parent_group = prandom_u32_max(ngroups);
281  		for (i = 0; i < ngroups; i++) {
282  			group = (parent_group + i) % ngroups;
283  			desc = ext2_get_group_desc (sb, group, NULL);
284  			if (!desc || !desc->bg_free_inodes_count)
285  				continue;
286  			if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
287  				continue;
288  			if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
289  				continue;
290  			if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
291  				continue;
292  			best_group = group;
293  			best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
294  			best_desc = desc;
295  		}
296  		if (best_group >= 0) {
297  			desc = best_desc;
298  			group = best_group;
299  			goto found;
300  		}
301  		goto fallback;
302  	}
303  
304  	if (ndirs == 0)
305  		ndirs = 1;	/* percpu_counters are approximate... */
306  
307  	blocks_per_dir = (le32_to_cpu(es->s_blocks_count)-free_blocks) / ndirs;
308  
309  	max_dirs = ndirs / ngroups + inodes_per_group / 16;
310  	min_inodes = avefreei - inodes_per_group / 4;
311  	min_blocks = avefreeb - EXT2_BLOCKS_PER_GROUP(sb) / 4;
312  
313  	max_debt = EXT2_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, BLOCK_COST);
314  	if (max_debt * INODE_COST > inodes_per_group)
315  		max_debt = inodes_per_group / INODE_COST;
316  	if (max_debt > 255)
317  		max_debt = 255;
318  	if (max_debt == 0)
319  		max_debt = 1;
320  
321  	for (i = 0; i < ngroups; i++) {
322  		group = (parent_group + i) % ngroups;
323  		desc = ext2_get_group_desc (sb, group, NULL);
324  		if (!desc || !desc->bg_free_inodes_count)
325  			continue;
326  		if (sbi->s_debts[group] >= max_debt)
327  			continue;
328  		if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
329  			continue;
330  		if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
331  			continue;
332  		if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
333  			continue;
334  		goto found;
335  	}
336  
337  fallback:
338  	for (i = 0; i < ngroups; i++) {
339  		group = (parent_group + i) % ngroups;
340  		desc = ext2_get_group_desc (sb, group, NULL);
341  		if (!desc || !desc->bg_free_inodes_count)
342  			continue;
343  		if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
344  			goto found;
345  	}
346  
347  	if (avefreei) {
348  		/*
349  		 * The free-inodes counter is approximate, and for really small
350  		 * filesystems the above test can fail to find any blockgroups
351  		 */
352  		avefreei = 0;
353  		goto fallback;
354  	}
355  
356  	return -1;
357  
358  found:
359  	return group;
360  }
361  
362  static int find_group_other(struct super_block *sb, struct inode *parent)
363  {
364  	int parent_group = EXT2_I(parent)->i_block_group;
365  	int ngroups = EXT2_SB(sb)->s_groups_count;
366  	struct ext2_group_desc *desc;
367  	int group, i;
368  
369  	/*
370  	 * Try to place the inode in its parent directory
371  	 */
372  	group = parent_group;
373  	desc = ext2_get_group_desc (sb, group, NULL);
374  	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
375  			le16_to_cpu(desc->bg_free_blocks_count))
376  		goto found;
377  
378  	/*
379  	 * We're going to place this inode in a different blockgroup from its
380  	 * parent.  We want to cause files in a common directory to all land in
381  	 * the same blockgroup.  But we want files which are in a different
382  	 * directory which shares a blockgroup with our parent to land in a
383  	 * different blockgroup.
384  	 *
385  	 * So add our directory's i_ino into the starting point for the hash.
386  	 */
387  	group = (group + parent->i_ino) % ngroups;
388  
389  	/*
390  	 * Use a quadratic hash to find a group with a free inode and some
391  	 * free blocks.
392  	 */
393  	for (i = 1; i < ngroups; i <<= 1) {
394  		group += i;
395  		if (group >= ngroups)
396  			group -= ngroups;
397  		desc = ext2_get_group_desc (sb, group, NULL);
398  		if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
399  				le16_to_cpu(desc->bg_free_blocks_count))
400  			goto found;
401  	}
402  
403  	/*
404  	 * That failed: try linear search for a free inode, even if that group
405  	 * has no free blocks.
406  	 */
407  	group = parent_group;
408  	for (i = 0; i < ngroups; i++) {
409  		if (++group >= ngroups)
410  			group = 0;
411  		desc = ext2_get_group_desc (sb, group, NULL);
412  		if (desc && le16_to_cpu(desc->bg_free_inodes_count))
413  			goto found;
414  	}
415  
416  	return -1;
417  
418  found:
419  	return group;
420  }
421  
422  struct inode *ext2_new_inode(struct inode *dir, umode_t mode,
423  			     const struct qstr *qstr)
424  {
425  	struct super_block *sb;
426  	struct buffer_head *bitmap_bh = NULL;
427  	struct buffer_head *bh2;
428  	int group, i;
429  	ino_t ino = 0;
430  	struct inode * inode;
431  	struct ext2_group_desc *gdp;
432  	struct ext2_super_block *es;
433  	struct ext2_inode_info *ei;
434  	struct ext2_sb_info *sbi;
435  	int err;
436  
437  	sb = dir->i_sb;
438  	inode = new_inode(sb);
439  	if (!inode)
440  		return ERR_PTR(-ENOMEM);
441  
442  	ei = EXT2_I(inode);
443  	sbi = EXT2_SB(sb);
444  	es = sbi->s_es;
445  	if (S_ISDIR(mode)) {
446  		if (test_opt(sb, OLDALLOC))
447  			group = find_group_dir(sb, dir);
448  		else
449  			group = find_group_orlov(sb, dir);
450  	} else
451  		group = find_group_other(sb, dir);
452  
453  	if (group == -1) {
454  		err = -ENOSPC;
455  		goto fail;
456  	}
457  
458  	for (i = 0; i < sbi->s_groups_count; i++) {
459  		gdp = ext2_get_group_desc(sb, group, &bh2);
460  		if (!gdp) {
461  			if (++group == sbi->s_groups_count)
462  				group = 0;
463  			continue;
464  		}
465  		brelse(bitmap_bh);
466  		bitmap_bh = read_inode_bitmap(sb, group);
467  		if (!bitmap_bh) {
468  			err = -EIO;
469  			goto fail;
470  		}
471  		ino = 0;
472  
473  repeat_in_this_group:
474  		ino = ext2_find_next_zero_bit((unsigned long *)bitmap_bh->b_data,
475  					      EXT2_INODES_PER_GROUP(sb), ino);
476  		if (ino >= EXT2_INODES_PER_GROUP(sb)) {
477  			/*
478  			 * Rare race: find_group_xx() decided that there were
479  			 * free inodes in this group, but by the time we tried
480  			 * to allocate one, they're all gone.  This can also
481  			 * occur because the counters which find_group_orlov()
482  			 * uses are approximate.  So just go and search the
483  			 * next block group.
484  			 */
485  			if (++group == sbi->s_groups_count)
486  				group = 0;
487  			continue;
488  		}
489  		if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group),
490  						ino, bitmap_bh->b_data)) {
491  			/* we lost this inode */
492  			if (++ino >= EXT2_INODES_PER_GROUP(sb)) {
493  				/* this group is exhausted, try next group */
494  				if (++group == sbi->s_groups_count)
495  					group = 0;
496  				continue;
497  			}
498  			/* try to find free inode in the same group */
499  			goto repeat_in_this_group;
500  		}
501  		goto got;
502  	}
503  
504  	/*
505  	 * Scanned all blockgroups.
506  	 */
507  	brelse(bitmap_bh);
508  	err = -ENOSPC;
509  	goto fail;
510  got:
511  	mark_buffer_dirty(bitmap_bh);
512  	if (sb->s_flags & SB_SYNCHRONOUS)
513  		sync_dirty_buffer(bitmap_bh);
514  	brelse(bitmap_bh);
515  
516  	ino += group * EXT2_INODES_PER_GROUP(sb) + 1;
517  	if (ino < EXT2_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
518  		ext2_error (sb, "ext2_new_inode",
519  			    "reserved inode or inode > inodes count - "
520  			    "block_group = %d,inode=%lu", group,
521  			    (unsigned long) ino);
522  		err = -EIO;
523  		goto fail;
524  	}
525  
526  	percpu_counter_dec(&sbi->s_freeinodes_counter);
527  	if (S_ISDIR(mode))
528  		percpu_counter_inc(&sbi->s_dirs_counter);
529  
530  	spin_lock(sb_bgl_lock(sbi, group));
531  	le16_add_cpu(&gdp->bg_free_inodes_count, -1);
532  	if (S_ISDIR(mode)) {
533  		if (sbi->s_debts[group] < 255)
534  			sbi->s_debts[group]++;
535  		le16_add_cpu(&gdp->bg_used_dirs_count, 1);
536  	} else {
537  		if (sbi->s_debts[group])
538  			sbi->s_debts[group]--;
539  	}
540  	spin_unlock(sb_bgl_lock(sbi, group));
541  
542  	mark_buffer_dirty(bh2);
543  	if (test_opt(sb, GRPID)) {
544  		inode->i_mode = mode;
545  		inode->i_uid = current_fsuid();
546  		inode->i_gid = dir->i_gid;
547  	} else
548  		inode_init_owner(&init_user_ns, inode, dir, mode);
549  
550  	inode->i_ino = ino;
551  	inode->i_blocks = 0;
552  	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
553  	memset(ei->i_data, 0, sizeof(ei->i_data));
554  	ei->i_flags =
555  		ext2_mask_flags(mode, EXT2_I(dir)->i_flags & EXT2_FL_INHERITED);
556  	ei->i_faddr = 0;
557  	ei->i_frag_no = 0;
558  	ei->i_frag_size = 0;
559  	ei->i_file_acl = 0;
560  	ei->i_dir_acl = 0;
561  	ei->i_dtime = 0;
562  	ei->i_block_alloc_info = NULL;
563  	ei->i_block_group = group;
564  	ei->i_dir_start_lookup = 0;
565  	ei->i_state = EXT2_STATE_NEW;
566  	ext2_set_inode_flags(inode);
567  	spin_lock(&sbi->s_next_gen_lock);
568  	inode->i_generation = sbi->s_next_generation++;
569  	spin_unlock(&sbi->s_next_gen_lock);
570  	if (insert_inode_locked(inode) < 0) {
571  		ext2_error(sb, "ext2_new_inode",
572  			   "inode number already in use - inode=%lu",
573  			   (unsigned long) ino);
574  		err = -EIO;
575  		goto fail;
576  	}
577  
578  	err = dquot_initialize(inode);
579  	if (err)
580  		goto fail_drop;
581  
582  	err = dquot_alloc_inode(inode);
583  	if (err)
584  		goto fail_drop;
585  
586  	err = ext2_init_acl(inode, dir);
587  	if (err)
588  		goto fail_free_drop;
589  
590  	err = ext2_init_security(inode, dir, qstr);
591  	if (err)
592  		goto fail_free_drop;
593  
594  	mark_inode_dirty(inode);
595  	ext2_debug("allocating inode %lu\n", inode->i_ino);
596  	ext2_preread_inode(inode);
597  	return inode;
598  
599  fail_free_drop:
600  	dquot_free_inode(inode);
601  
602  fail_drop:
603  	dquot_drop(inode);
604  	inode->i_flags |= S_NOQUOTA;
605  	clear_nlink(inode);
606  	discard_new_inode(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  
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",
646  		(unsigned long)
647  		percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
648  		desc_count, bitmap_count);
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  
676