2 * linux/fs/ext3/ialloc.c
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
9 * BSD ufs-inspired inode and directory allocation by
10 * Stephen Tweedie (sct@redhat.com), 1993
11 * Big-endian to little-endian byte-swapping/bitmaps by
12 * David S. Miller (davem@caip.rutgers.edu), 1995
15 #include <linux/time.h>
17 #include <linux/jbd.h>
18 #include <linux/ext3_fs.h>
19 #include <linux/ext3_jbd.h>
20 #include <linux/stat.h>
21 #include <linux/string.h>
22 #include <linux/quotaops.h>
23 #include <linux/buffer_head.h>
24 #include <linux/random.h>
25 #include <linux/bitops.h>
27 #include <asm/byteorder.h>
33 * ialloc.c contains the inodes allocation and deallocation routines
37 * The free inodes are managed by bitmaps. A file system contains several
38 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
39 * block for inodes, N blocks for the inode table and data blocks.
41 * The file system contains group descriptors which are located after the
42 * super block. Each descriptor contains the number of the bitmap block and
43 * the free blocks count in the block.
48 * Read the inode allocation bitmap for a given block_group, reading
49 * into the specified slot in the superblock's bitmap cache.
51 * Return buffer_head of bitmap on success or NULL.
53 static struct buffer_head *
54 read_inode_bitmap(struct super_block * sb, unsigned long block_group)
56 struct ext3_group_desc *desc;
57 struct buffer_head *bh = NULL;
59 desc = ext3_get_group_desc(sb, block_group, NULL);
63 bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
65 ext3_error(sb, "read_inode_bitmap",
66 "Cannot read inode bitmap - "
67 "block_group = %lu, inode_bitmap = %u",
68 block_group, le32_to_cpu(desc->bg_inode_bitmap));
74 * NOTE! When we get the inode, we're the only people
75 * that have access to it, and as such there are no
76 * race conditions we have to worry about. The inode
77 * is not on the hash-lists, and it cannot be reached
78 * through the filesystem because the directory entry
79 * has been deleted earlier.
81 * HOWEVER: we must make sure that we get no aliases,
82 * which means that we have to call "clear_inode()"
83 * _before_ we mark the inode not in use in the inode
84 * bitmaps. Otherwise a newly created file might use
85 * the same inode number (not actually the same pointer
86 * though), and then we'd have two inodes sharing the
87 * same inode number and space on the harddisk.
89 void ext3_free_inode (handle_t *handle, struct inode * inode)
91 struct super_block * sb = inode->i_sb;
94 struct buffer_head *bitmap_bh = NULL;
95 struct buffer_head *bh2;
96 unsigned long block_group;
98 struct ext3_group_desc * gdp;
99 struct ext3_super_block * es;
100 struct ext3_sb_info *sbi;
103 if (atomic_read(&inode->i_count) > 1) {
104 printk ("ext3_free_inode: inode has count=%d\n",
105 atomic_read(&inode->i_count));
108 if (inode->i_nlink) {
109 printk ("ext3_free_inode: inode has nlink=%d\n",
114 printk("ext3_free_inode: inode on nonexistent device\n");
120 ext3_debug ("freeing inode %lu\n", ino);
123 * Note: we must free any quota before locking the superblock,
124 * as writing the quota to disk may need the lock as well.
127 ext3_xattr_delete_inode(handle, inode);
128 DQUOT_FREE_INODE(inode);
131 is_directory = S_ISDIR(inode->i_mode);
133 /* Do this BEFORE marking the inode not in use or returning an error */
136 es = EXT3_SB(sb)->s_es;
137 if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
138 ext3_error (sb, "ext3_free_inode",
139 "reserved or nonexistent inode %lu", ino);
142 block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
143 bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
144 bitmap_bh = read_inode_bitmap(sb, block_group);
148 BUFFER_TRACE(bitmap_bh, "get_write_access");
149 fatal = ext3_journal_get_write_access(handle, bitmap_bh);
153 /* Ok, now we can actually update the inode bitmaps.. */
154 if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
155 bit, bitmap_bh->b_data))
156 ext3_error (sb, "ext3_free_inode",
157 "bit already cleared for inode %lu", ino);
159 gdp = ext3_get_group_desc (sb, block_group, &bh2);
161 BUFFER_TRACE(bh2, "get_write_access");
162 fatal = ext3_journal_get_write_access(handle, bh2);
163 if (fatal) goto error_return;
166 spin_lock(sb_bgl_lock(sbi, block_group));
167 gdp->bg_free_inodes_count = cpu_to_le16(
168 le16_to_cpu(gdp->bg_free_inodes_count) + 1);
170 gdp->bg_used_dirs_count = cpu_to_le16(
171 le16_to_cpu(gdp->bg_used_dirs_count) - 1);
172 spin_unlock(sb_bgl_lock(sbi, block_group));
173 percpu_counter_inc(&sbi->s_freeinodes_counter);
175 percpu_counter_dec(&sbi->s_dirs_counter);
178 BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
179 err = ext3_journal_dirty_metadata(handle, bh2);
180 if (!fatal) fatal = err;
182 BUFFER_TRACE(bitmap_bh, "call ext3_journal_dirty_metadata");
183 err = ext3_journal_dirty_metadata(handle, bitmap_bh);
189 ext3_std_error(sb, fatal);
193 * There are two policies for allocating an inode. If the new inode is
194 * a directory, then a forward search is made for a block group with both
195 * free space and a low directory-to-inode ratio; if that fails, then of
196 * the groups with above-average free space, that group with the fewest
197 * directories already is chosen.
199 * For other inodes, search forward from the parent directory\'s block
200 * group to find a free inode.
202 static int find_group_dir(struct super_block *sb, struct inode *parent)
204 int ngroups = EXT3_SB(sb)->s_groups_count;
206 struct ext3_group_desc *desc, *best_desc = NULL;
207 struct buffer_head *bh;
208 int group, best_group = -1;
210 freei = percpu_counter_read_positive(&EXT3_SB(sb)->s_freeinodes_counter);
211 avefreei = freei / ngroups;
213 for (group = 0; group < ngroups; group++) {
214 desc = ext3_get_group_desc (sb, group, &bh);
215 if (!desc || !desc->bg_free_inodes_count)
217 if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
220 (le16_to_cpu(desc->bg_free_blocks_count) >
221 le16_to_cpu(best_desc->bg_free_blocks_count))) {
230 * Orlov's allocator for directories.
232 * We always try to spread first-level directories.
234 * If there are blockgroups with both free inodes and free blocks counts
235 * not worse than average we return one with smallest directory count.
236 * Otherwise we simply return a random group.
238 * For the rest rules look so:
240 * It's OK to put directory into a group unless
241 * it has too many directories already (max_dirs) or
242 * it has too few free inodes left (min_inodes) or
243 * it has too few free blocks left (min_blocks) or
244 * it's already running too large debt (max_debt).
245 * Parent's group is prefered, if it doesn't satisfy these
246 * conditions we search cyclically through the rest. If none
247 * of the groups look good we just look for a group with more
248 * free inodes than average (starting at parent's group).
250 * Debt is incremented each time we allocate a directory and decremented
251 * when we allocate an inode, within 0--255.
254 #define INODE_COST 64
255 #define BLOCK_COST 256
257 static int find_group_orlov(struct super_block *sb, struct inode *parent)
259 int parent_group = EXT3_I(parent)->i_block_group;
260 struct ext3_sb_info *sbi = EXT3_SB(sb);
261 struct ext3_super_block *es = sbi->s_es;
262 int ngroups = sbi->s_groups_count;
263 int inodes_per_group = EXT3_INODES_PER_GROUP(sb);
265 ext3_fsblk_t freeb, avefreeb;
266 ext3_fsblk_t blocks_per_dir;
268 int max_debt, max_dirs, min_inodes;
269 ext3_grpblk_t min_blocks;
271 struct ext3_group_desc *desc;
272 struct buffer_head *bh;
274 freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
275 avefreei = freei / ngroups;
276 freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
277 avefreeb = freeb / ngroups;
278 ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
280 if ((parent == sb->s_root->d_inode) ||
281 (EXT3_I(parent)->i_flags & EXT3_TOPDIR_FL)) {
282 int best_ndir = inodes_per_group;
285 get_random_bytes(&group, sizeof(group));
286 parent_group = (unsigned)group % ngroups;
287 for (i = 0; i < ngroups; i++) {
288 group = (parent_group + i) % ngroups;
289 desc = ext3_get_group_desc (sb, group, &bh);
290 if (!desc || !desc->bg_free_inodes_count)
292 if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
294 if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
296 if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
299 best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
306 blocks_per_dir = (le32_to_cpu(es->s_blocks_count) - freeb) / ndirs;
308 max_dirs = ndirs / ngroups + inodes_per_group / 16;
309 min_inodes = avefreei - inodes_per_group / 4;
310 min_blocks = avefreeb - EXT3_BLOCKS_PER_GROUP(sb) / 4;
312 max_debt = EXT3_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, (ext3_fsblk_t)BLOCK_COST);
313 if (max_debt * INODE_COST > inodes_per_group)
314 max_debt = inodes_per_group / INODE_COST;
320 for (i = 0; i < ngroups; i++) {
321 group = (parent_group + i) % ngroups;
322 desc = ext3_get_group_desc (sb, group, &bh);
323 if (!desc || !desc->bg_free_inodes_count)
325 if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
327 if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
329 if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
335 for (i = 0; i < ngroups; i++) {
336 group = (parent_group + i) % ngroups;
337 desc = ext3_get_group_desc (sb, group, &bh);
338 if (!desc || !desc->bg_free_inodes_count)
340 if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
346 * The free-inodes counter is approximate, and for really small
347 * filesystems the above test can fail to find any blockgroups
356 static int find_group_other(struct super_block *sb, struct inode *parent)
358 int parent_group = EXT3_I(parent)->i_block_group;
359 int ngroups = EXT3_SB(sb)->s_groups_count;
360 struct ext3_group_desc *desc;
361 struct buffer_head *bh;
365 * Try to place the inode in its parent directory
367 group = parent_group;
368 desc = ext3_get_group_desc (sb, group, &bh);
369 if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
370 le16_to_cpu(desc->bg_free_blocks_count))
374 * We're going to place this inode in a different blockgroup from its
375 * parent. We want to cause files in a common directory to all land in
376 * the same blockgroup. But we want files which are in a different
377 * directory which shares a blockgroup with our parent to land in a
378 * different blockgroup.
380 * So add our directory's i_ino into the starting point for the hash.
382 group = (group + parent->i_ino) % ngroups;
385 * Use a quadratic hash to find a group with a free inode and some free
388 for (i = 1; i < ngroups; i <<= 1) {
390 if (group >= ngroups)
392 desc = ext3_get_group_desc (sb, group, &bh);
393 if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
394 le16_to_cpu(desc->bg_free_blocks_count))
399 * That failed: try linear search for a free inode, even if that group
400 * has no free blocks.
402 group = parent_group;
403 for (i = 0; i < ngroups; i++) {
404 if (++group >= ngroups)
406 desc = ext3_get_group_desc (sb, group, &bh);
407 if (desc && le16_to_cpu(desc->bg_free_inodes_count))
415 * There are two policies for allocating an inode. If the new inode is
416 * a directory, then a forward search is made for a block group with both
417 * free space and a low directory-to-inode ratio; if that fails, then of
418 * the groups with above-average free space, that group with the fewest
419 * directories already is chosen.
421 * For other inodes, search forward from the parent directory's block
422 * group to find a free inode.
424 struct inode *ext3_new_inode(handle_t *handle, struct inode * dir, int mode)
426 struct super_block *sb;
427 struct buffer_head *bitmap_bh = NULL;
428 struct buffer_head *bh2;
430 unsigned long ino = 0;
431 struct inode * inode;
432 struct ext3_group_desc * gdp = NULL;
433 struct ext3_super_block * es;
434 struct ext3_inode_info *ei;
435 struct ext3_sb_info *sbi;
440 /* Cannot create files in a deleted directory */
441 if (!dir || !dir->i_nlink)
442 return ERR_PTR(-EPERM);
445 inode = new_inode(sb);
447 return ERR_PTR(-ENOMEM);
453 if (test_opt (sb, OLDALLOC))
454 group = find_group_dir(sb, dir);
456 group = find_group_orlov(sb, dir);
458 group = find_group_other(sb, dir);
464 for (i = 0; i < sbi->s_groups_count; i++) {
467 gdp = ext3_get_group_desc(sb, group, &bh2);
472 bitmap_bh = read_inode_bitmap(sb, group);
478 repeat_in_this_group:
479 ino = ext3_find_next_zero_bit((unsigned long *)
480 bitmap_bh->b_data, EXT3_INODES_PER_GROUP(sb), ino);
481 if (ino < EXT3_INODES_PER_GROUP(sb)) {
483 BUFFER_TRACE(bitmap_bh, "get_write_access");
484 err = ext3_journal_get_write_access(handle, bitmap_bh);
488 if (!ext3_set_bit_atomic(sb_bgl_lock(sbi, group),
489 ino, bitmap_bh->b_data)) {
491 BUFFER_TRACE(bitmap_bh,
492 "call ext3_journal_dirty_metadata");
493 err = ext3_journal_dirty_metadata(handle,
500 journal_release_buffer(handle, bitmap_bh);
502 if (++ino < EXT3_INODES_PER_GROUP(sb))
503 goto repeat_in_this_group;
507 * This case is possible in concurrent environment. It is very
508 * rare. We cannot repeat the find_group_xxx() call because
509 * that will simply return the same blockgroup, because the
510 * group descriptor metadata has not yet been updated.
511 * So we just go onto the next blockgroup.
513 if (++group == sbi->s_groups_count)
520 ino += group * EXT3_INODES_PER_GROUP(sb) + 1;
521 if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
522 ext3_error (sb, "ext3_new_inode",
523 "reserved inode or inode > inodes count - "
524 "block_group = %d, inode=%lu", group, ino);
529 BUFFER_TRACE(bh2, "get_write_access");
530 err = ext3_journal_get_write_access(handle, bh2);
532 spin_lock(sb_bgl_lock(sbi, group));
533 gdp->bg_free_inodes_count =
534 cpu_to_le16(le16_to_cpu(gdp->bg_free_inodes_count) - 1);
536 gdp->bg_used_dirs_count =
537 cpu_to_le16(le16_to_cpu(gdp->bg_used_dirs_count) + 1);
539 spin_unlock(sb_bgl_lock(sbi, group));
540 BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
541 err = ext3_journal_dirty_metadata(handle, bh2);
544 percpu_counter_dec(&sbi->s_freeinodes_counter);
546 percpu_counter_inc(&sbi->s_dirs_counter);
549 inode->i_uid = current->fsuid;
550 if (test_opt (sb, GRPID))
551 inode->i_gid = dir->i_gid;
552 else if (dir->i_mode & S_ISGID) {
553 inode->i_gid = dir->i_gid;
557 inode->i_gid = current->fsgid;
558 inode->i_mode = mode;
561 /* This is the optimal IO size (for stat), not the fs block size */
562 inode->i_blksize = PAGE_SIZE;
564 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
566 memset(ei->i_data, 0, sizeof(ei->i_data));
567 ei->i_dir_start_lookup = 0;
570 ei->i_flags = EXT3_I(dir)->i_flags & ~EXT3_INDEX_FL;
572 ei->i_flags &= ~(EXT3_IMMUTABLE_FL|EXT3_APPEND_FL);
573 /* dirsync only applies to directories */
575 ei->i_flags &= ~EXT3_DIRSYNC_FL;
576 #ifdef EXT3_FRAGMENTS
584 ei->i_block_alloc_info = NULL;
585 ei->i_block_group = group;
587 ext3_set_inode_flags(inode);
588 if (IS_DIRSYNC(inode))
590 insert_inode_hash(inode);
591 spin_lock(&sbi->s_next_gen_lock);
592 inode->i_generation = sbi->s_next_generation++;
593 spin_unlock(&sbi->s_next_gen_lock);
595 ei->i_state = EXT3_STATE_NEW;
597 (EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) ?
598 sizeof(struct ext3_inode) - EXT3_GOOD_OLD_INODE_SIZE : 0;
601 if(DQUOT_ALLOC_INODE(inode)) {
606 err = ext3_init_acl(handle, inode, dir);
610 err = ext3_init_security(handle,inode, dir);
614 err = ext3_mark_inode_dirty(handle, inode);
616 ext3_std_error(sb, err);
620 ext3_debug("allocating inode %lu\n", inode->i_ino);
623 ext3_std_error(sb, err);
632 DQUOT_FREE_INODE(inode);
636 inode->i_flags |= S_NOQUOTA;
643 /* Verify that we are loading a valid orphan from disk */
644 struct inode *ext3_orphan_get(struct super_block *sb, unsigned long ino)
646 unsigned long max_ino = le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count);
647 unsigned long block_group;
649 struct buffer_head *bitmap_bh = NULL;
650 struct inode *inode = NULL;
652 /* Error cases - e2fsck has already cleaned up for us */
654 ext3_warning(sb, __FUNCTION__,
655 "bad orphan ino %lu! e2fsck was run?", ino);
659 block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
660 bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
661 bitmap_bh = read_inode_bitmap(sb, block_group);
663 ext3_warning(sb, __FUNCTION__,
664 "inode bitmap error for orphan %lu", ino);
668 /* Having the inode bit set should be a 100% indicator that this
669 * is a valid orphan (no e2fsck run on fs). Orphans also include
670 * inodes that were being truncated, so we can't check i_nlink==0.
672 if (!ext3_test_bit(bit, bitmap_bh->b_data) ||
673 !(inode = iget(sb, ino)) || is_bad_inode(inode) ||
674 NEXT_ORPHAN(inode) > max_ino) {
675 ext3_warning(sb, __FUNCTION__,
676 "bad orphan inode %lu! e2fsck was run?", ino);
677 printk(KERN_NOTICE "ext3_test_bit(bit=%d, block=%llu) = %d\n",
678 bit, (unsigned long long)bitmap_bh->b_blocknr,
679 ext3_test_bit(bit, bitmap_bh->b_data));
680 printk(KERN_NOTICE "inode=%p\n", inode);
682 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
683 is_bad_inode(inode));
684 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
686 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
688 /* Avoid freeing blocks if we got a bad deleted inode */
689 if (inode && inode->i_nlink == 0)
699 unsigned long ext3_count_free_inodes (struct super_block * sb)
701 unsigned long desc_count;
702 struct ext3_group_desc *gdp;
705 struct ext3_super_block *es;
706 unsigned long bitmap_count, x;
707 struct buffer_head *bitmap_bh = NULL;
709 es = EXT3_SB(sb)->s_es;
713 for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
714 gdp = ext3_get_group_desc (sb, i, NULL);
717 desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
719 bitmap_bh = read_inode_bitmap(sb, i);
723 x = ext3_count_free(bitmap_bh, EXT3_INODES_PER_GROUP(sb) / 8);
724 printk("group %d: stored = %d, counted = %lu\n",
725 i, le16_to_cpu(gdp->bg_free_inodes_count), x);
729 printk("ext3_count_free_inodes: stored = %u, computed = %lu, %lu\n",
730 le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
734 for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
735 gdp = ext3_get_group_desc (sb, i, NULL);
738 desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
745 /* Called at mount-time, super-block is locked */
746 unsigned long ext3_count_dirs (struct super_block * sb)
748 unsigned long count = 0;
751 for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
752 struct ext3_group_desc *gdp = ext3_get_group_desc (sb, i, NULL);
755 count += le16_to_cpu(gdp->bg_used_dirs_count);