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Linux/fs/ext2/ialloc.c

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  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         if (dir)
 84                 percpu_counter_dec(&EXT2_SB(sb)->s_dirs_counter);
 85         mark_buffer_dirty(bh);
 86 }
 87 
 88 /*
 89  * NOTE! When we get the inode, we're the only people
 90  * that have access to it, and as such there are no
 91  * race conditions we have to worry about. The inode
 92  * is not on the hash-lists, and it cannot be reached
 93  * through the filesystem because the directory entry
 94  * has been deleted earlier.
 95  *
 96  * HOWEVER: we must make sure that we get no aliases,
 97  * which means that we have to call "clear_inode()"
 98  * _before_ we mark the inode not in use in the inode
 99  * bitmaps. Otherwise a newly created file might use
100  * the same inode number (not actually the same pointer
101  * though), and then we'd have two inodes sharing the
102  * same inode number and space on the harddisk.
103  */
104 void ext2_free_inode (struct inode * inode)
105 {
106         struct super_block * sb = inode->i_sb;
107         int is_directory;
108         unsigned long ino;
109         struct buffer_head *bitmap_bh;
110         unsigned long block_group;
111         unsigned long bit;
112         struct ext2_super_block * es;
113 
114         ino = inode->i_ino;
115         ext2_debug ("freeing inode %lu\n", ino);
116 
117         /*
118          * Note: we must free any quota before locking the superblock,
119          * as writing the quota to disk may need the lock as well.
120          */
121         /* Quota is already initialized in iput() */
122         dquot_free_inode(inode);
123         dquot_drop(inode);
124 
125         es = EXT2_SB(sb)->s_es;
126         is_directory = S_ISDIR(inode->i_mode);
127 
128         if (ino < EXT2_FIRST_INO(sb) ||
129             ino > le32_to_cpu(es->s_inodes_count)) {
130                 ext2_error (sb, "ext2_free_inode",
131                             "reserved or nonexistent inode %lu", ino);
132                 return;
133         }
134         block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
135         bit = (ino - 1) % EXT2_INODES_PER_GROUP(sb);
136         bitmap_bh = read_inode_bitmap(sb, block_group);
137         if (!bitmap_bh)
138                 return;
139 
140         /* Ok, now we can actually update the inode bitmaps.. */
141         if (!ext2_clear_bit_atomic(sb_bgl_lock(EXT2_SB(sb), block_group),
142                                 bit, (void *) bitmap_bh->b_data))
143                 ext2_error (sb, "ext2_free_inode",
144                               "bit already cleared for inode %lu", ino);
145         else
146                 ext2_release_inode(sb, block_group, is_directory);
147         mark_buffer_dirty(bitmap_bh);
148         if (sb->s_flags & SB_SYNCHRONOUS)
149                 sync_dirty_buffer(bitmap_bh);
150 
151         brelse(bitmap_bh);
152 }
153 
154 /*
155  * We perform asynchronous prereading of the new inode's inode block when
156  * we create the inode, in the expectation that the inode will be written
157  * back soon.  There are two reasons:
158  *
159  * - When creating a large number of files, the async prereads will be
160  *   nicely merged into large reads
161  * - When writing out a large number of inodes, we don't need to keep on
162  *   stalling the writes while we read the inode block.
163  *
164  * FIXME: ext2_get_group_desc() needs to be simplified.
165  */
166 static void ext2_preread_inode(struct inode *inode)
167 {
168         unsigned long block_group;
169         unsigned long offset;
170         unsigned long block;
171         struct ext2_group_desc * gdp;
172         struct backing_dev_info *bdi;
173 
174         bdi = inode_to_bdi(inode);
175         if (bdi_rw_congested(bdi))
176                 return;
177 
178         block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
179         gdp = ext2_get_group_desc(inode->i_sb, block_group, NULL);
180         if (gdp == NULL)
181                 return;
182 
183         /*
184          * Figure out the offset within the block group inode table
185          */
186         offset = ((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb)) *
187                                 EXT2_INODE_SIZE(inode->i_sb);
188         block = le32_to_cpu(gdp->bg_inode_table) +
189                                 (offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));
190         sb_breadahead(inode->i_sb, block);
191 }
192 
193 /*
194  * There are two policies for allocating an inode.  If the new inode is
195  * a directory, then a forward search is made for a block group with both
196  * free space and a low directory-to-inode ratio; if that fails, then of
197  * the groups with above-average free space, that group with the fewest
198  * directories already is chosen.
199  *
200  * For other inodes, search forward from the parent directory\'s block
201  * group to find a free inode.
202  */
203 static int find_group_dir(struct super_block *sb, struct inode *parent)
204 {
205         int ngroups = EXT2_SB(sb)->s_groups_count;
206         int avefreei = ext2_count_free_inodes(sb) / ngroups;
207         struct ext2_group_desc *desc, *best_desc = NULL;
208         int group, best_group = -1;
209 
210         for (group = 0; group < ngroups; group++) {
211                 desc = ext2_get_group_desc (sb, group, NULL);
212                 if (!desc || !desc->bg_free_inodes_count)
213                         continue;
214                 if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
215                         continue;
216                 if (!best_desc || 
217                     (le16_to_cpu(desc->bg_free_blocks_count) >
218                      le16_to_cpu(best_desc->bg_free_blocks_count))) {
219                         best_group = group;
220                         best_desc = desc;
221                 }
222         }
223 
224         return best_group;
225 }
226 
227 /* 
228  * Orlov's allocator for directories. 
229  * 
230  * We always try to spread first-level directories.
231  *
232  * If there are blockgroups with both free inodes and free blocks counts 
233  * not worse than average we return one with smallest directory count. 
234  * Otherwise we simply return a random group. 
235  * 
236  * For the rest rules look so: 
237  * 
238  * It's OK to put directory into a group unless 
239  * it has too many directories already (max_dirs) or 
240  * it has too few free inodes left (min_inodes) or 
241  * it has too few free blocks left (min_blocks) or 
242  * it's already running too large debt (max_debt). 
243  * Parent's group is preferred, if it doesn't satisfy these 
244  * conditions we search cyclically through the rest. If none 
245  * of the groups look good we just look for a group with more 
246  * free inodes than average (starting at parent's group). 
247  * 
248  * Debt is incremented each time we allocate a directory and decremented 
249  * when we allocate an inode, within 0--255. 
250  */ 
251 
252 #define INODE_COST 64
253 #define BLOCK_COST 256
254 
255 static int find_group_orlov(struct super_block *sb, struct inode *parent)
256 {
257         int parent_group = EXT2_I(parent)->i_block_group;
258         struct ext2_sb_info *sbi = EXT2_SB(sb);
259         struct ext2_super_block *es = sbi->s_es;
260         int ngroups = sbi->s_groups_count;
261         int inodes_per_group = EXT2_INODES_PER_GROUP(sb);
262         int freei;
263         int avefreei;
264         int free_blocks;
265         int avefreeb;
266         int blocks_per_dir;
267         int ndirs;
268         int max_debt, max_dirs, min_blocks, min_inodes;
269         int group = -1, i;
270         struct ext2_group_desc *desc;
271 
272         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
273         avefreei = freei / ngroups;
274         free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
275         avefreeb = free_blocks / ngroups;
276         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
277 
278         if ((parent == d_inode(sb->s_root)) ||
279             (EXT2_I(parent)->i_flags & EXT2_TOPDIR_FL)) {
280                 struct ext2_group_desc *best_desc = NULL;
281                 int best_ndir = inodes_per_group;
282                 int best_group = -1;
283 
284                 group = prandom_u32();
285                 parent_group = (unsigned)group % ngroups;
286                 for (i = 0; i < ngroups; i++) {
287                         group = (parent_group + i) % ngroups;
288                         desc = ext2_get_group_desc (sb, group, NULL);
289                         if (!desc || !desc->bg_free_inodes_count)
290                                 continue;
291                         if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
292                                 continue;
293                         if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
294                                 continue;
295                         if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
296                                 continue;
297                         best_group = group;
298                         best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
299                         best_desc = desc;
300                 }
301                 if (best_group >= 0) {
302                         desc = best_desc;
303                         group = best_group;
304                         goto found;
305                 }
306                 goto fallback;
307         }
308 
309         if (ndirs == 0)
310                 ndirs = 1;      /* percpu_counters are approximate... */
311 
312         blocks_per_dir = (le32_to_cpu(es->s_blocks_count)-free_blocks) / ndirs;
313 
314         max_dirs = ndirs / ngroups + inodes_per_group / 16;
315         min_inodes = avefreei - inodes_per_group / 4;
316         min_blocks = avefreeb - EXT2_BLOCKS_PER_GROUP(sb) / 4;
317 
318         max_debt = EXT2_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, BLOCK_COST);
319         if (max_debt * INODE_COST > inodes_per_group)
320                 max_debt = inodes_per_group / INODE_COST;
321         if (max_debt > 255)
322                 max_debt = 255;
323         if (max_debt == 0)
324                 max_debt = 1;
325 
326         for (i = 0; i < ngroups; i++) {
327                 group = (parent_group + i) % ngroups;
328                 desc = ext2_get_group_desc (sb, group, NULL);
329                 if (!desc || !desc->bg_free_inodes_count)
330                         continue;
331                 if (sbi->s_debts[group] >= max_debt)
332                         continue;
333                 if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
334                         continue;
335                 if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
336                         continue;
337                 if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
338                         continue;
339                 goto found;
340         }
341 
342 fallback:
343         for (i = 0; i < ngroups; i++) {
344                 group = (parent_group + i) % ngroups;
345                 desc = ext2_get_group_desc (sb, group, NULL);
346                 if (!desc || !desc->bg_free_inodes_count)
347                         continue;
348                 if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
349                         goto found;
350         }
351 
352         if (avefreei) {
353                 /*
354                  * The free-inodes counter is approximate, and for really small
355                  * filesystems the above test can fail to find any blockgroups
356                  */
357                 avefreei = 0;
358                 goto fallback;
359         }
360 
361         return -1;
362 
363 found:
364         return group;
365 }
366 
367 static int find_group_other(struct super_block *sb, struct inode *parent)
368 {
369         int parent_group = EXT2_I(parent)->i_block_group;
370         int ngroups = EXT2_SB(sb)->s_groups_count;
371         struct ext2_group_desc *desc;
372         int group, i;
373 
374         /*
375          * Try to place the inode in its parent directory
376          */
377         group = parent_group;
378         desc = ext2_get_group_desc (sb, group, NULL);
379         if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
380                         le16_to_cpu(desc->bg_free_blocks_count))
381                 goto found;
382 
383         /*
384          * We're going to place this inode in a different blockgroup from its
385          * parent.  We want to cause files in a common directory to all land in
386          * the same blockgroup.  But we want files which are in a different
387          * directory which shares a blockgroup with our parent to land in a
388          * different blockgroup.
389          *
390          * So add our directory's i_ino into the starting point for the hash.
391          */
392         group = (group + parent->i_ino) % ngroups;
393 
394         /*
395          * Use a quadratic hash to find a group with a free inode and some
396          * free blocks.
397          */
398         for (i = 1; i < ngroups; i <<= 1) {
399                 group += i;
400                 if (group >= ngroups)
401                         group -= ngroups;
402                 desc = ext2_get_group_desc (sb, group, NULL);
403                 if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
404                                 le16_to_cpu(desc->bg_free_blocks_count))
405                         goto found;
406         }
407 
408         /*
409          * That failed: try linear search for a free inode, even if that group
410          * has no free blocks.
411          */
412         group = parent_group;
413         for (i = 0; i < ngroups; i++) {
414                 if (++group >= ngroups)
415                         group = 0;
416                 desc = ext2_get_group_desc (sb, group, NULL);
417                 if (desc && le16_to_cpu(desc->bg_free_inodes_count))
418                         goto found;
419         }
420 
421         return -1;
422 
423 found:
424         return group;
425 }
426 
427 struct inode *ext2_new_inode(struct inode *dir, umode_t mode,
428                              const struct qstr *qstr)
429 {
430         struct super_block *sb;
431         struct buffer_head *bitmap_bh = NULL;
432         struct buffer_head *bh2;
433         int group, i;
434         ino_t ino = 0;
435         struct inode * inode;
436         struct ext2_group_desc *gdp;
437         struct ext2_super_block *es;
438         struct ext2_inode_info *ei;
439         struct ext2_sb_info *sbi;
440         int err;
441 
442         sb = dir->i_sb;
443         inode = new_inode(sb);
444         if (!inode)
445                 return ERR_PTR(-ENOMEM);
446 
447         ei = EXT2_I(inode);
448         sbi = EXT2_SB(sb);
449         es = sbi->s_es;
450         if (S_ISDIR(mode)) {
451                 if (test_opt(sb, OLDALLOC))
452                         group = find_group_dir(sb, dir);
453                 else
454                         group = find_group_orlov(sb, dir);
455         } else 
456                 group = find_group_other(sb, dir);
457 
458         if (group == -1) {
459                 err = -ENOSPC;
460                 goto fail;
461         }
462 
463         for (i = 0; i < sbi->s_groups_count; i++) {
464                 gdp = ext2_get_group_desc(sb, group, &bh2);
465                 if (!gdp) {
466                         if (++group == sbi->s_groups_count)
467                                 group = 0;
468                         continue;
469                 }
470                 brelse(bitmap_bh);
471                 bitmap_bh = read_inode_bitmap(sb, group);
472                 if (!bitmap_bh) {
473                         err = -EIO;
474                         goto fail;
475                 }
476                 ino = 0;
477 
478 repeat_in_this_group:
479                 ino = ext2_find_next_zero_bit((unsigned long *)bitmap_bh->b_data,
480                                               EXT2_INODES_PER_GROUP(sb), ino);
481                 if (ino >= EXT2_INODES_PER_GROUP(sb)) {
482                         /*
483                          * Rare race: find_group_xx() decided that there were
484                          * free inodes in this group, but by the time we tried
485                          * to allocate one, they're all gone.  This can also
486                          * occur because the counters which find_group_orlov()
487                          * uses are approximate.  So just go and search the
488                          * next block group.
489                          */
490                         if (++group == sbi->s_groups_count)
491                                 group = 0;
492                         continue;
493                 }
494                 if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group),
495                                                 ino, bitmap_bh->b_data)) {
496                         /* we lost this inode */
497                         if (++ino >= EXT2_INODES_PER_GROUP(sb)) {
498                                 /* this group is exhausted, try next group */
499                                 if (++group == sbi->s_groups_count)
500                                         group = 0;
501                                 continue;
502                         }
503                         /* try to find free inode in the same group */
504                         goto repeat_in_this_group;
505                 }
506                 goto got;
507         }
508 
509         /*
510          * Scanned all blockgroups.
511          */
512         brelse(bitmap_bh);
513         err = -ENOSPC;
514         goto fail;
515 got:
516         mark_buffer_dirty(bitmap_bh);
517         if (sb->s_flags & SB_SYNCHRONOUS)
518                 sync_dirty_buffer(bitmap_bh);
519         brelse(bitmap_bh);
520 
521         ino += group * EXT2_INODES_PER_GROUP(sb) + 1;
522         if (ino < EXT2_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
523                 ext2_error (sb, "ext2_new_inode",
524                             "reserved inode or inode > inodes count - "
525                             "block_group = %d,inode=%lu", group,
526                             (unsigned long) ino);
527                 err = -EIO;
528                 goto fail;
529         }
530 
531         percpu_counter_add(&sbi->s_freeinodes_counter, -1);
532         if (S_ISDIR(mode))
533                 percpu_counter_inc(&sbi->s_dirs_counter);
534 
535         spin_lock(sb_bgl_lock(sbi, group));
536         le16_add_cpu(&gdp->bg_free_inodes_count, -1);
537         if (S_ISDIR(mode)) {
538                 if (sbi->s_debts[group] < 255)
539                         sbi->s_debts[group]++;
540                 le16_add_cpu(&gdp->bg_used_dirs_count, 1);
541         } else {
542                 if (sbi->s_debts[group])
543                         sbi->s_debts[group]--;
544         }
545         spin_unlock(sb_bgl_lock(sbi, group));
546 
547         mark_buffer_dirty(bh2);
548         if (test_opt(sb, GRPID)) {
549                 inode->i_mode = mode;
550                 inode->i_uid = current_fsuid();
551                 inode->i_gid = dir->i_gid;
552         } else
553                 inode_init_owner(inode, dir, mode);
554 
555         inode->i_ino = ino;
556         inode->i_blocks = 0;
557         inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
558         memset(ei->i_data, 0, sizeof(ei->i_data));
559         ei->i_flags =
560                 ext2_mask_flags(mode, EXT2_I(dir)->i_flags & EXT2_FL_INHERITED);
561         ei->i_faddr = 0;
562         ei->i_frag_no = 0;
563         ei->i_frag_size = 0;
564         ei->i_file_acl = 0;
565         ei->i_dir_acl = 0;
566         ei->i_dtime = 0;
567         ei->i_block_alloc_info = NULL;
568         ei->i_block_group = group;
569         ei->i_dir_start_lookup = 0;
570         ei->i_state = EXT2_STATE_NEW;
571         ext2_set_inode_flags(inode);
572         spin_lock(&sbi->s_next_gen_lock);
573         inode->i_generation = sbi->s_next_generation++;
574         spin_unlock(&sbi->s_next_gen_lock);
575         if (insert_inode_locked(inode) < 0) {
576                 ext2_error(sb, "ext2_new_inode",
577                            "inode number already in use - inode=%lu",
578                            (unsigned long) ino);
579                 err = -EIO;
580                 goto fail;
581         }
582 
583         err = dquot_initialize(inode);
584         if (err)
585                 goto fail_drop;
586 
587         err = dquot_alloc_inode(inode);
588         if (err)
589                 goto fail_drop;
590 
591         err = ext2_init_acl(inode, dir);
592         if (err)
593                 goto fail_free_drop;
594 
595         err = ext2_init_security(inode, dir, qstr);
596         if (err)
597                 goto fail_free_drop;
598 
599         mark_inode_dirty(inode);
600         ext2_debug("allocating inode %lu\n", inode->i_ino);
601         ext2_preread_inode(inode);
602         return inode;
603 
604 fail_free_drop:
605         dquot_free_inode(inode);
606 
607 fail_drop:
608         dquot_drop(inode);
609         inode->i_flags |= S_NOQUOTA;
610         clear_nlink(inode);
611         discard_new_inode(inode);
612         return ERR_PTR(err);
613 
614 fail:
615         make_bad_inode(inode);
616         iput(inode);
617         return ERR_PTR(err);
618 }
619 
620 unsigned long ext2_count_free_inodes (struct super_block * sb)
621 {
622         struct ext2_group_desc *desc;
623         unsigned long desc_count = 0;
624         int i;  
625 
626 #ifdef EXT2FS_DEBUG
627         struct ext2_super_block *es;
628         unsigned long bitmap_count = 0;
629         struct buffer_head *bitmap_bh = NULL;
630 
631         es = EXT2_SB(sb)->s_es;
632         for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
633                 unsigned x;
634 
635                 desc = ext2_get_group_desc (sb, i, NULL);
636                 if (!desc)
637                         continue;
638                 desc_count += le16_to_cpu(desc->bg_free_inodes_count);
639                 brelse(bitmap_bh);
640                 bitmap_bh = read_inode_bitmap(sb, i);
641                 if (!bitmap_bh)
642                         continue;
643 
644                 x = ext2_count_free(bitmap_bh, EXT2_INODES_PER_GROUP(sb) / 8);
645                 printk("group %d: stored = %d, counted = %u\n",
646                         i, le16_to_cpu(desc->bg_free_inodes_count), x);
647                 bitmap_count += x;
648         }
649         brelse(bitmap_bh);
650         printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
651                 (unsigned long)
652                 percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
653                 desc_count, bitmap_count);
654         return desc_count;
655 #else
656         for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
657                 desc = ext2_get_group_desc (sb, i, NULL);
658                 if (!desc)
659                         continue;
660                 desc_count += le16_to_cpu(desc->bg_free_inodes_count);
661         }
662         return desc_count;
663 #endif
664 }
665 
666 /* Called at mount-time, super-block is locked */
667 unsigned long ext2_count_dirs (struct super_block * sb)
668 {
669         unsigned long count = 0;
670         int i;
671 
672         for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
673                 struct ext2_group_desc *gdp = ext2_get_group_desc (sb, i, NULL);
674                 if (!gdp)
675                         continue;
676                 count += le16_to_cpu(gdp->bg_used_dirs_count);
677         }
678         return count;
679 }
680 
681 

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