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1/*
2 * linux/fs/ext4/ialloc.c
3 *
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)
8 *
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
13 */
14
15#include <linux/time.h>
16#include <linux/fs.h>
17#include <linux/jbd2.h>
18#include <linux/stat.h>
19#include <linux/string.h>
20#include <linux/quotaops.h>
21#include <linux/buffer_head.h>
22#include <linux/random.h>
23#include <linux/bitops.h>
24#include <linux/blkdev.h>
25#include <asm/byteorder.h>
26
27#include "ext4.h"
28#include "ext4_jbd2.h"
29#include "xattr.h"
30#include "acl.h"
31
32#include <trace/events/ext4.h>
33
34/*
35 * ialloc.c contains the inodes allocation and deallocation routines
36 */
37
38/*
39 * The free inodes are managed by bitmaps. A file system contains several
40 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
41 * block for inodes, N blocks for the inode table and data blocks.
42 *
43 * The file system contains group descriptors which are located after the
44 * super block. Each descriptor contains the number of the bitmap block and
45 * the free blocks count in the block.
46 */
47
48/*
49 * To avoid calling the atomic setbit hundreds or thousands of times, we only
50 * need to use it within a single byte (to ensure we get endianness right).
51 * We can use memset for the rest of the bitmap as there are no other users.
52 */
53void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
54{
55 int i;
56
57 if (start_bit >= end_bit)
58 return;
59
60 ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
61 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
62 ext4_set_bit(i, bitmap);
63 if (i < end_bit)
64 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
65}
66
67/* Initializes an uninitialized inode bitmap */
68static unsigned ext4_init_inode_bitmap(struct super_block *sb,
69 struct buffer_head *bh,
70 ext4_group_t block_group,
71 struct ext4_group_desc *gdp)
72{
73 struct ext4_sb_info *sbi = EXT4_SB(sb);
74
75 J_ASSERT_BH(bh, buffer_locked(bh));
76
77 /* If checksum is bad mark all blocks and inodes use to prevent
78 * allocation, essentially implementing a per-group read-only flag. */
79 if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
80 ext4_error(sb, "Checksum bad for group %u", block_group);
81 ext4_free_blks_set(sb, gdp, 0);
82 ext4_free_inodes_set(sb, gdp, 0);
83 ext4_itable_unused_set(sb, gdp, 0);
84 memset(bh->b_data, 0xff, sb->s_blocksize);
85 return 0;
86 }
87
88 memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
89 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
90 bh->b_data);
91
92 return EXT4_INODES_PER_GROUP(sb);
93}
94
95/*
96 * Read the inode allocation bitmap for a given block_group, reading
97 * into the specified slot in the superblock's bitmap cache.
98 *
99 * Return buffer_head of bitmap on success or NULL.
100 */
101static struct buffer_head *
102ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
103{
104 struct ext4_group_desc *desc;
105 struct buffer_head *bh = NULL;
106 ext4_fsblk_t bitmap_blk;
107
108 desc = ext4_get_group_desc(sb, block_group, NULL);
109 if (!desc)
110 return NULL;
111
112 bitmap_blk = ext4_inode_bitmap(sb, desc);
113 bh = sb_getblk(sb, bitmap_blk);
114 if (unlikely(!bh)) {
115 ext4_error(sb, "Cannot read inode bitmap - "
116 "block_group = %u, inode_bitmap = %llu",
117 block_group, bitmap_blk);
118 return NULL;
119 }
120 if (bitmap_uptodate(bh))
121 return bh;
122
123 lock_buffer(bh);
124 if (bitmap_uptodate(bh)) {
125 unlock_buffer(bh);
126 return bh;
127 }
128
129 ext4_lock_group(sb, block_group);
130 if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
131 ext4_init_inode_bitmap(sb, bh, block_group, desc);
132 set_bitmap_uptodate(bh);
133 set_buffer_uptodate(bh);
134 ext4_unlock_group(sb, block_group);
135 unlock_buffer(bh);
136 return bh;
137 }
138 ext4_unlock_group(sb, block_group);
139
140 if (buffer_uptodate(bh)) {
141 /*
142 * if not uninit if bh is uptodate,
143 * bitmap is also uptodate
144 */
145 set_bitmap_uptodate(bh);
146 unlock_buffer(bh);
147 return bh;
148 }
149 /*
150 * submit the buffer_head for read. We can
151 * safely mark the bitmap as uptodate now.
152 * We do it here so the bitmap uptodate bit
153 * get set with buffer lock held.
154 */
155 trace_ext4_load_inode_bitmap(sb, block_group);
156 set_bitmap_uptodate(bh);
157 if (bh_submit_read(bh) < 0) {
158 put_bh(bh);
159 ext4_error(sb, "Cannot read inode bitmap - "
160 "block_group = %u, inode_bitmap = %llu",
161 block_group, bitmap_blk);
162 return NULL;
163 }
164 return bh;
165}
166
167/*
168 * NOTE! When we get the inode, we're the only people
169 * that have access to it, and as such there are no
170 * race conditions we have to worry about. The inode
171 * is not on the hash-lists, and it cannot be reached
172 * through the filesystem because the directory entry
173 * has been deleted earlier.
174 *
175 * HOWEVER: we must make sure that we get no aliases,
176 * which means that we have to call "clear_inode()"
177 * _before_ we mark the inode not in use in the inode
178 * bitmaps. Otherwise a newly created file might use
179 * the same inode number (not actually the same pointer
180 * though), and then we'd have two inodes sharing the
181 * same inode number and space on the harddisk.
182 */
183void ext4_free_inode(handle_t *handle, struct inode *inode)
184{
185 struct super_block *sb = inode->i_sb;
186 int is_directory;
187 unsigned long ino;
188 struct buffer_head *bitmap_bh = NULL;
189 struct buffer_head *bh2;
190 ext4_group_t block_group;
191 unsigned long bit;
192 struct ext4_group_desc *gdp;
193 struct ext4_super_block *es;
194 struct ext4_sb_info *sbi;
195 int fatal = 0, err, count, cleared;
196
197 if (atomic_read(&inode->i_count) > 1) {
198 printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
199 atomic_read(&inode->i_count));
200 return;
201 }
202 if (inode->i_nlink) {
203 printk(KERN_ERR "ext4_free_inode: inode has nlink=%d\n",
204 inode->i_nlink);
205 return;
206 }
207 if (!sb) {
208 printk(KERN_ERR "ext4_free_inode: inode on "
209 "nonexistent device\n");
210 return;
211 }
212 sbi = EXT4_SB(sb);
213
214 ino = inode->i_ino;
215 ext4_debug("freeing inode %lu\n", ino);
216 trace_ext4_free_inode(inode);
217
218 /*
219 * Note: we must free any quota before locking the superblock,
220 * as writing the quota to disk may need the lock as well.
221 */
222 dquot_initialize(inode);
223 ext4_xattr_delete_inode(handle, inode);
224 dquot_free_inode(inode);
225 dquot_drop(inode);
226
227 is_directory = S_ISDIR(inode->i_mode);
228
229 /* Do this BEFORE marking the inode not in use or returning an error */
230 ext4_clear_inode(inode);
231
232 es = EXT4_SB(sb)->s_es;
233 if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
234 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
235 goto error_return;
236 }
237 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
238 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
239 bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
240 if (!bitmap_bh)
241 goto error_return;
242
243 BUFFER_TRACE(bitmap_bh, "get_write_access");
244 fatal = ext4_journal_get_write_access(handle, bitmap_bh);
245 if (fatal)
246 goto error_return;
247
248 fatal = -ESRCH;
249 gdp = ext4_get_group_desc(sb, block_group, &bh2);
250 if (gdp) {
251 BUFFER_TRACE(bh2, "get_write_access");
252 fatal = ext4_journal_get_write_access(handle, bh2);
253 }
254 ext4_lock_group(sb, block_group);
255 cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
256 if (fatal || !cleared) {
257 ext4_unlock_group(sb, block_group);
258 goto out;
259 }
260
261 count = ext4_free_inodes_count(sb, gdp) + 1;
262 ext4_free_inodes_set(sb, gdp, count);
263 if (is_directory) {
264 count = ext4_used_dirs_count(sb, gdp) - 1;
265 ext4_used_dirs_set(sb, gdp, count);
266 percpu_counter_dec(&sbi->s_dirs_counter);
267 }
268 gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
269 ext4_unlock_group(sb, block_group);
270
271 percpu_counter_inc(&sbi->s_freeinodes_counter);
272 if (sbi->s_log_groups_per_flex) {
273 ext4_group_t f = ext4_flex_group(sbi, block_group);
274
275 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
276 if (is_directory)
277 atomic_dec(&sbi->s_flex_groups[f].used_dirs);
278 }
279 BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
280 fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
281out:
282 if (cleared) {
283 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
284 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
285 if (!fatal)
286 fatal = err;
287 ext4_mark_super_dirty(sb);
288 } else
289 ext4_error(sb, "bit already cleared for inode %lu", ino);
290
291error_return:
292 brelse(bitmap_bh);
293 ext4_std_error(sb, fatal);
294}
295
296/*
297 * There are two policies for allocating an inode. If the new inode is
298 * a directory, then a forward search is made for a block group with both
299 * free space and a low directory-to-inode ratio; if that fails, then of
300 * the groups with above-average free space, that group with the fewest
301 * directories already is chosen.
302 *
303 * For other inodes, search forward from the parent directory\'s block
304 * group to find a free inode.
305 */
306static int find_group_dir(struct super_block *sb, struct inode *parent,
307 ext4_group_t *best_group)
308{
309 ext4_group_t ngroups = ext4_get_groups_count(sb);
310 unsigned int freei, avefreei;
311 struct ext4_group_desc *desc, *best_desc = NULL;
312 ext4_group_t group;
313 int ret = -1;
314
315 freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
316 avefreei = freei / ngroups;
317
318 for (group = 0; group < ngroups; group++) {
319 desc = ext4_get_group_desc(sb, group, NULL);
320 if (!desc || !ext4_free_inodes_count(sb, desc))
321 continue;
322 if (ext4_free_inodes_count(sb, desc) < avefreei)
323 continue;
324 if (!best_desc ||
325 (ext4_free_blks_count(sb, desc) >
326 ext4_free_blks_count(sb, best_desc))) {
327 *best_group = group;
328 best_desc = desc;
329 ret = 0;
330 }
331 }
332 return ret;
333}
334
335#define free_block_ratio 10
336
337static int find_group_flex(struct super_block *sb, struct inode *parent,
338 ext4_group_t *best_group)
339{
340 struct ext4_sb_info *sbi = EXT4_SB(sb);
341 struct ext4_group_desc *desc;
342 struct flex_groups *flex_group = sbi->s_flex_groups;
343 ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
344 ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
345 ext4_group_t ngroups = ext4_get_groups_count(sb);
346 int flex_size = ext4_flex_bg_size(sbi);
347 ext4_group_t best_flex = parent_fbg_group;
348 int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
349 int flexbg_free_blocks;
350 int flex_freeb_ratio;
351 ext4_group_t n_fbg_groups;
352 ext4_group_t i;
353
354 n_fbg_groups = (ngroups + flex_size - 1) >>
355 sbi->s_log_groups_per_flex;
356
357find_close_to_parent:
358 flexbg_free_blocks = atomic_read(&flex_group[best_flex].free_blocks);
359 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
360 if (atomic_read(&flex_group[best_flex].free_inodes) &&
361 flex_freeb_ratio > free_block_ratio)
362 goto found_flexbg;
363
364 if (best_flex && best_flex == parent_fbg_group) {
365 best_flex--;
366 goto find_close_to_parent;
367 }
368
369 for (i = 0; i < n_fbg_groups; i++) {
370 if (i == parent_fbg_group || i == parent_fbg_group - 1)
371 continue;
372
373 flexbg_free_blocks = atomic_read(&flex_group[i].free_blocks);
374 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
375
376 if (flex_freeb_ratio > free_block_ratio &&
377 (atomic_read(&flex_group[i].free_inodes))) {
378 best_flex = i;
379 goto found_flexbg;
380 }
381
382 if ((atomic_read(&flex_group[best_flex].free_inodes) == 0) ||
383 ((atomic_read(&flex_group[i].free_blocks) >
384 atomic_read(&flex_group[best_flex].free_blocks)) &&
385 atomic_read(&flex_group[i].free_inodes)))
386 best_flex = i;
387 }
388
389 if (!atomic_read(&flex_group[best_flex].free_inodes) ||
390 !atomic_read(&flex_group[best_flex].free_blocks))
391 return -1;
392
393found_flexbg:
394 for (i = best_flex * flex_size; i < ngroups &&
395 i < (best_flex + 1) * flex_size; i++) {
396 desc = ext4_get_group_desc(sb, i, NULL);
397 if (ext4_free_inodes_count(sb, desc)) {
398 *best_group = i;
399 goto out;
400 }
401 }
402
403 return -1;
404out:
405 return 0;
406}
407
408struct orlov_stats {
409 __u32 free_inodes;
410 __u32 free_blocks;
411 __u32 used_dirs;
412};
413
414/*
415 * Helper function for Orlov's allocator; returns critical information
416 * for a particular block group or flex_bg. If flex_size is 1, then g
417 * is a block group number; otherwise it is flex_bg number.
418 */
419static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
420 int flex_size, struct orlov_stats *stats)
421{
422 struct ext4_group_desc *desc;
423 struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
424
425 if (flex_size > 1) {
426 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
427 stats->free_blocks = atomic_read(&flex_group[g].free_blocks);
428 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
429 return;
430 }
431
432 desc = ext4_get_group_desc(sb, g, NULL);
433 if (desc) {
434 stats->free_inodes = ext4_free_inodes_count(sb, desc);
435 stats->free_blocks = ext4_free_blks_count(sb, desc);
436 stats->used_dirs = ext4_used_dirs_count(sb, desc);
437 } else {
438 stats->free_inodes = 0;
439 stats->free_blocks = 0;
440 stats->used_dirs = 0;
441 }
442}
443
444/*
445 * Orlov's allocator for directories.
446 *
447 * We always try to spread first-level directories.
448 *
449 * If there are blockgroups with both free inodes and free blocks counts
450 * not worse than average we return one with smallest directory count.
451 * Otherwise we simply return a random group.
452 *
453 * For the rest rules look so:
454 *
455 * It's OK to put directory into a group unless
456 * it has too many directories already (max_dirs) or
457 * it has too few free inodes left (min_inodes) or
458 * it has too few free blocks left (min_blocks) or
459 * Parent's group is preferred, if it doesn't satisfy these
460 * conditions we search cyclically through the rest. If none
461 * of the groups look good we just look for a group with more
462 * free inodes than average (starting at parent's group).
463 */
464
465static int find_group_orlov(struct super_block *sb, struct inode *parent,
466 ext4_group_t *group, int mode,
467 const struct qstr *qstr)
468{
469 ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
470 struct ext4_sb_info *sbi = EXT4_SB(sb);
471 ext4_group_t real_ngroups = ext4_get_groups_count(sb);
472 int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
473 unsigned int freei, avefreei;
474 ext4_fsblk_t freeb, avefreeb;
475 unsigned int ndirs;
476 int max_dirs, min_inodes;
477 ext4_grpblk_t min_blocks;
478 ext4_group_t i, grp, g, ngroups;
479 struct ext4_group_desc *desc;
480 struct orlov_stats stats;
481 int flex_size = ext4_flex_bg_size(sbi);
482 struct dx_hash_info hinfo;
483
484 ngroups = real_ngroups;
485 if (flex_size > 1) {
486 ngroups = (real_ngroups + flex_size - 1) >>
487 sbi->s_log_groups_per_flex;
488 parent_group >>= sbi->s_log_groups_per_flex;
489 }
490
491 freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
492 avefreei = freei / ngroups;
493 freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
494 avefreeb = freeb;
495 do_div(avefreeb, ngroups);
496 ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
497
498 if (S_ISDIR(mode) &&
499 ((parent == sb->s_root->d_inode) ||
500 (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
501 int best_ndir = inodes_per_group;
502 int ret = -1;
503
504 if (qstr) {
505 hinfo.hash_version = DX_HASH_HALF_MD4;
506 hinfo.seed = sbi->s_hash_seed;
507 ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
508 grp = hinfo.hash;
509 } else
510 get_random_bytes(&grp, sizeof(grp));
511 parent_group = (unsigned)grp % ngroups;
512 for (i = 0; i < ngroups; i++) {
513 g = (parent_group + i) % ngroups;
514 get_orlov_stats(sb, g, flex_size, &stats);
515 if (!stats.free_inodes)
516 continue;
517 if (stats.used_dirs >= best_ndir)
518 continue;
519 if (stats.free_inodes < avefreei)
520 continue;
521 if (stats.free_blocks < avefreeb)
522 continue;
523 grp = g;
524 ret = 0;
525 best_ndir = stats.used_dirs;
526 }
527 if (ret)
528 goto fallback;
529 found_flex_bg:
530 if (flex_size == 1) {
531 *group = grp;
532 return 0;
533 }
534
535 /*
536 * We pack inodes at the beginning of the flexgroup's
537 * inode tables. Block allocation decisions will do
538 * something similar, although regular files will
539 * start at 2nd block group of the flexgroup. See
540 * ext4_ext_find_goal() and ext4_find_near().
541 */
542 grp *= flex_size;
543 for (i = 0; i < flex_size; i++) {
544 if (grp+i >= real_ngroups)
545 break;
546 desc = ext4_get_group_desc(sb, grp+i, NULL);
547 if (desc && ext4_free_inodes_count(sb, desc)) {
548 *group = grp+i;
549 return 0;
550 }
551 }
552 goto fallback;
553 }
554
555 max_dirs = ndirs / ngroups + inodes_per_group / 16;
556 min_inodes = avefreei - inodes_per_group*flex_size / 4;
557 if (min_inodes < 1)
558 min_inodes = 1;
559 min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb)*flex_size / 4;
560
561 /*
562 * Start looking in the flex group where we last allocated an
563 * inode for this parent directory
564 */
565 if (EXT4_I(parent)->i_last_alloc_group != ~0) {
566 parent_group = EXT4_I(parent)->i_last_alloc_group;
567 if (flex_size > 1)
568 parent_group >>= sbi->s_log_groups_per_flex;
569 }
570
571 for (i = 0; i < ngroups; i++) {
572 grp = (parent_group + i) % ngroups;
573 get_orlov_stats(sb, grp, flex_size, &stats);
574 if (stats.used_dirs >= max_dirs)
575 continue;
576 if (stats.free_inodes < min_inodes)
577 continue;
578 if (stats.free_blocks < min_blocks)
579 continue;
580 goto found_flex_bg;
581 }
582
583fallback:
584 ngroups = real_ngroups;
585 avefreei = freei / ngroups;
586fallback_retry:
587 parent_group = EXT4_I(parent)->i_block_group;
588 for (i = 0; i < ngroups; i++) {
589 grp = (parent_group + i) % ngroups;
590 desc = ext4_get_group_desc(sb, grp, NULL);
591 if (desc && ext4_free_inodes_count(sb, desc) &&
592 ext4_free_inodes_count(sb, desc) >= avefreei) {
593 *group = grp;
594 return 0;
595 }
596 }
597
598 if (avefreei) {
599 /*
600 * The free-inodes counter is approximate, and for really small
601 * filesystems the above test can fail to find any blockgroups
602 */
603 avefreei = 0;
604 goto fallback_retry;
605 }
606
607 return -1;
608}
609
610static int find_group_other(struct super_block *sb, struct inode *parent,
611 ext4_group_t *group, int mode)
612{
613 ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
614 ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
615 struct ext4_group_desc *desc;
616 int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
617
618 /*
619 * Try to place the inode is the same flex group as its
620 * parent. If we can't find space, use the Orlov algorithm to
621 * find another flex group, and store that information in the
622 * parent directory's inode information so that use that flex
623 * group for future allocations.
624 */
625 if (flex_size > 1) {
626 int retry = 0;
627
628 try_again:
629 parent_group &= ~(flex_size-1);
630 last = parent_group + flex_size;
631 if (last > ngroups)
632 last = ngroups;
633 for (i = parent_group; i < last; i++) {
634 desc = ext4_get_group_desc(sb, i, NULL);
635 if (desc && ext4_free_inodes_count(sb, desc)) {
636 *group = i;
637 return 0;
638 }
639 }
640 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
641 retry = 1;
642 parent_group = EXT4_I(parent)->i_last_alloc_group;
643 goto try_again;
644 }
645 /*
646 * If this didn't work, use the Orlov search algorithm
647 * to find a new flex group; we pass in the mode to
648 * avoid the topdir algorithms.
649 */
650 *group = parent_group + flex_size;
651 if (*group > ngroups)
652 *group = 0;
653 return find_group_orlov(sb, parent, group, mode, NULL);
654 }
655
656 /*
657 * Try to place the inode in its parent directory
658 */
659 *group = parent_group;
660 desc = ext4_get_group_desc(sb, *group, NULL);
661 if (desc && ext4_free_inodes_count(sb, desc) &&
662 ext4_free_blks_count(sb, desc))
663 return 0;
664
665 /*
666 * We're going to place this inode in a different blockgroup from its
667 * parent. We want to cause files in a common directory to all land in
668 * the same blockgroup. But we want files which are in a different
669 * directory which shares a blockgroup with our parent to land in a
670 * different blockgroup.
671 *
672 * So add our directory's i_ino into the starting point for the hash.
673 */
674 *group = (*group + parent->i_ino) % ngroups;
675
676 /*
677 * Use a quadratic hash to find a group with a free inode and some free
678 * blocks.
679 */
680 for (i = 1; i < ngroups; i <<= 1) {
681 *group += i;
682 if (*group >= ngroups)
683 *group -= ngroups;
684 desc = ext4_get_group_desc(sb, *group, NULL);
685 if (desc && ext4_free_inodes_count(sb, desc) &&
686 ext4_free_blks_count(sb, desc))
687 return 0;
688 }
689
690 /*
691 * That failed: try linear search for a free inode, even if that group
692 * has no free blocks.
693 */
694 *group = parent_group;
695 for (i = 0; i < ngroups; i++) {
696 if (++*group >= ngroups)
697 *group = 0;
698 desc = ext4_get_group_desc(sb, *group, NULL);
699 if (desc && ext4_free_inodes_count(sb, desc))
700 return 0;
701 }
702
703 return -1;
704}
705
706/*
707 * claim the inode from the inode bitmap. If the group
708 * is uninit we need to take the groups's ext4_group_lock
709 * and clear the uninit flag. The inode bitmap update
710 * and group desc uninit flag clear should be done
711 * after holding ext4_group_lock so that ext4_read_inode_bitmap
712 * doesn't race with the ext4_claim_inode
713 */
714static int ext4_claim_inode(struct super_block *sb,
715 struct buffer_head *inode_bitmap_bh,
716 unsigned long ino, ext4_group_t group, int mode)
717{
718 int free = 0, retval = 0, count;
719 struct ext4_sb_info *sbi = EXT4_SB(sb);
720 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
721 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
722
723 /*
724 * We have to be sure that new inode allocation does not race with
725 * inode table initialization, because otherwise we may end up
726 * allocating and writing new inode right before sb_issue_zeroout
727 * takes place and overwriting our new inode with zeroes. So we
728 * take alloc_sem to prevent it.
729 */
730 down_read(&grp->alloc_sem);
731 ext4_lock_group(sb, group);
732 if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
733 /* not a free inode */
734 retval = 1;
735 goto err_ret;
736 }
737 ino++;
738 if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
739 ino > EXT4_INODES_PER_GROUP(sb)) {
740 ext4_unlock_group(sb, group);
741 up_read(&grp->alloc_sem);
742 ext4_error(sb, "reserved inode or inode > inodes count - "
743 "block_group = %u, inode=%lu", group,
744 ino + group * EXT4_INODES_PER_GROUP(sb));
745 return 1;
746 }
747 /* If we didn't allocate from within the initialized part of the inode
748 * table then we need to initialize up to this inode. */
749 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
750
751 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
752 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
753 /* When marking the block group with
754 * ~EXT4_BG_INODE_UNINIT we don't want to depend
755 * on the value of bg_itable_unused even though
756 * mke2fs could have initialized the same for us.
757 * Instead we calculated the value below
758 */
759
760 free = 0;
761 } else {
762 free = EXT4_INODES_PER_GROUP(sb) -
763 ext4_itable_unused_count(sb, gdp);
764 }
765
766 /*
767 * Check the relative inode number against the last used
768 * relative inode number in this group. if it is greater
769 * we need to update the bg_itable_unused count
770 *
771 */
772 if (ino > free)
773 ext4_itable_unused_set(sb, gdp,
774 (EXT4_INODES_PER_GROUP(sb) - ino));
775 }
776 count = ext4_free_inodes_count(sb, gdp) - 1;
777 ext4_free_inodes_set(sb, gdp, count);
778 if (S_ISDIR(mode)) {
779 count = ext4_used_dirs_count(sb, gdp) + 1;
780 ext4_used_dirs_set(sb, gdp, count);
781 if (sbi->s_log_groups_per_flex) {
782 ext4_group_t f = ext4_flex_group(sbi, group);
783
784 atomic_inc(&sbi->s_flex_groups[f].used_dirs);
785 }
786 }
787 gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
788err_ret:
789 ext4_unlock_group(sb, group);
790 up_read(&grp->alloc_sem);
791 return retval;
792}
793
794/*
795 * There are two policies for allocating an inode. If the new inode is
796 * a directory, then a forward search is made for a block group with both
797 * free space and a low directory-to-inode ratio; if that fails, then of
798 * the groups with above-average free space, that group with the fewest
799 * directories already is chosen.
800 *
801 * For other inodes, search forward from the parent directory's block
802 * group to find a free inode.
803 */
804struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode,
805 const struct qstr *qstr, __u32 goal)
806{
807 struct super_block *sb;
808 struct buffer_head *inode_bitmap_bh = NULL;
809 struct buffer_head *group_desc_bh;
810 ext4_group_t ngroups, group = 0;
811 unsigned long ino = 0;
812 struct inode *inode;
813 struct ext4_group_desc *gdp = NULL;
814 struct ext4_inode_info *ei;
815 struct ext4_sb_info *sbi;
816 int ret2, err = 0;
817 struct inode *ret;
818 ext4_group_t i;
819 int free = 0;
820 static int once = 1;
821 ext4_group_t flex_group;
822
823 /* Cannot create files in a deleted directory */
824 if (!dir || !dir->i_nlink)
825 return ERR_PTR(-EPERM);
826
827 sb = dir->i_sb;
828 ngroups = ext4_get_groups_count(sb);
829 trace_ext4_request_inode(dir, mode);
830 inode = new_inode(sb);
831 if (!inode)
832 return ERR_PTR(-ENOMEM);
833 ei = EXT4_I(inode);
834 sbi = EXT4_SB(sb);
835
836 if (!goal)
837 goal = sbi->s_inode_goal;
838
839 if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
840 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
841 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
842 ret2 = 0;
843 goto got_group;
844 }
845
846 if (sbi->s_log_groups_per_flex && test_opt(sb, OLDALLOC)) {
847 ret2 = find_group_flex(sb, dir, &group);
848 if (ret2 == -1) {
849 ret2 = find_group_other(sb, dir, &group, mode);
850 if (ret2 == 0 && once) {
851 once = 0;
852 printk(KERN_NOTICE "ext4: find_group_flex "
853 "failed, fallback succeeded dir %lu\n",
854 dir->i_ino);
855 }
856 }
857 goto got_group;
858 }
859
860 if (S_ISDIR(mode)) {
861 if (test_opt(sb, OLDALLOC))
862 ret2 = find_group_dir(sb, dir, &group);
863 else
864 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
865 } else
866 ret2 = find_group_other(sb, dir, &group, mode);
867
868got_group:
869 EXT4_I(dir)->i_last_alloc_group = group;
870 err = -ENOSPC;
871 if (ret2 == -1)
872 goto out;
873
874 for (i = 0; i < ngroups; i++, ino = 0) {
875 err = -EIO;
876
877 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
878 if (!gdp)
879 goto fail;
880
881 brelse(inode_bitmap_bh);
882 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
883 if (!inode_bitmap_bh)
884 goto fail;
885
886repeat_in_this_group:
887 ino = ext4_find_next_zero_bit((unsigned long *)
888 inode_bitmap_bh->b_data,
889 EXT4_INODES_PER_GROUP(sb), ino);
890
891 if (ino < EXT4_INODES_PER_GROUP(sb)) {
892
893 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
894 err = ext4_journal_get_write_access(handle,
895 inode_bitmap_bh);
896 if (err)
897 goto fail;
898
899 BUFFER_TRACE(group_desc_bh, "get_write_access");
900 err = ext4_journal_get_write_access(handle,
901 group_desc_bh);
902 if (err)
903 goto fail;
904 if (!ext4_claim_inode(sb, inode_bitmap_bh,
905 ino, group, mode)) {
906 /* we won it */
907 BUFFER_TRACE(inode_bitmap_bh,
908 "call ext4_handle_dirty_metadata");
909 err = ext4_handle_dirty_metadata(handle,
910 NULL,
911 inode_bitmap_bh);
912 if (err)
913 goto fail;
914 /* zero bit is inode number 1*/
915 ino++;
916 goto got;
917 }
918 /* we lost it */
919 ext4_handle_release_buffer(handle, inode_bitmap_bh);
920 ext4_handle_release_buffer(handle, group_desc_bh);
921
922 if (++ino < EXT4_INODES_PER_GROUP(sb))
923 goto repeat_in_this_group;
924 }
925
926 /*
927 * This case is possible in concurrent environment. It is very
928 * rare. We cannot repeat the find_group_xxx() call because
929 * that will simply return the same blockgroup, because the
930 * group descriptor metadata has not yet been updated.
931 * So we just go onto the next blockgroup.
932 */
933 if (++group == ngroups)
934 group = 0;
935 }
936 err = -ENOSPC;
937 goto out;
938
939got:
940 /* We may have to initialize the block bitmap if it isn't already */
941 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
942 gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
943 struct buffer_head *block_bitmap_bh;
944
945 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
946 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
947 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
948 if (err) {
949 brelse(block_bitmap_bh);
950 goto fail;
951 }
952
953 free = 0;
954 ext4_lock_group(sb, group);
955 /* recheck and clear flag under lock if we still need to */
956 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
957 free = ext4_free_blocks_after_init(sb, group, gdp);
958 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
959 ext4_free_blks_set(sb, gdp, free);
960 gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
961 gdp);
962 }
963 ext4_unlock_group(sb, group);
964
965 /* Don't need to dirty bitmap block if we didn't change it */
966 if (free) {
967 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
968 err = ext4_handle_dirty_metadata(handle,
969 NULL, block_bitmap_bh);
970 }
971
972 brelse(block_bitmap_bh);
973 if (err)
974 goto fail;
975 }
976 BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
977 err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
978 if (err)
979 goto fail;
980
981 percpu_counter_dec(&sbi->s_freeinodes_counter);
982 if (S_ISDIR(mode))
983 percpu_counter_inc(&sbi->s_dirs_counter);
984 ext4_mark_super_dirty(sb);
985
986 if (sbi->s_log_groups_per_flex) {
987 flex_group = ext4_flex_group(sbi, group);
988 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
989 }
990
991 if (test_opt(sb, GRPID)) {
992 inode->i_mode = mode;
993 inode->i_uid = current_fsuid();
994 inode->i_gid = dir->i_gid;
995 } else
996 inode_init_owner(inode, dir, mode);
997
998 inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
999 /* This is the optimal IO size (for stat), not the fs block size */
1000 inode->i_blocks = 0;
1001 inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
1002 ext4_current_time(inode);
1003
1004 memset(ei->i_data, 0, sizeof(ei->i_data));
1005 ei->i_dir_start_lookup = 0;
1006 ei->i_disksize = 0;
1007
1008 /*
1009 * Don't inherit extent flag from directory, amongst others. We set
1010 * extent flag on newly created directory and file only if -o extent
1011 * mount option is specified
1012 */
1013 ei->i_flags =
1014 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1015 ei->i_file_acl = 0;
1016 ei->i_dtime = 0;
1017 ei->i_block_group = group;
1018 ei->i_last_alloc_group = ~0;
1019
1020 ext4_set_inode_flags(inode);
1021 if (IS_DIRSYNC(inode))
1022 ext4_handle_sync(handle);
1023 if (insert_inode_locked(inode) < 0) {
1024 err = -EINVAL;
1025 goto fail_drop;
1026 }
1027 spin_lock(&sbi->s_next_gen_lock);
1028 inode->i_generation = sbi->s_next_generation++;
1029 spin_unlock(&sbi->s_next_gen_lock);
1030
1031 ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1032 ext4_set_inode_state(inode, EXT4_STATE_NEW);
1033
1034 ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
1035
1036 ret = inode;
1037 dquot_initialize(inode);
1038 err = dquot_alloc_inode(inode);
1039 if (err)
1040 goto fail_drop;
1041
1042 err = ext4_init_acl(handle, inode, dir);
1043 if (err)
1044 goto fail_free_drop;
1045
1046 err = ext4_init_security(handle, inode, dir, qstr);
1047 if (err)
1048 goto fail_free_drop;
1049
1050 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
1051 /* set extent flag only for directory, file and normal symlink*/
1052 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1053 ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1054 ext4_ext_tree_init(handle, inode);
1055 }
1056 }
1057
1058 if (ext4_handle_valid(handle)) {
1059 ei->i_sync_tid = handle->h_transaction->t_tid;
1060 ei->i_datasync_tid = handle->h_transaction->t_tid;
1061 }
1062
1063 err = ext4_mark_inode_dirty(handle, inode);
1064 if (err) {
1065 ext4_std_error(sb, err);
1066 goto fail_free_drop;
1067 }
1068
1069 ext4_debug("allocating inode %lu\n", inode->i_ino);
1070 trace_ext4_allocate_inode(inode, dir, mode);
1071 goto really_out;
1072fail:
1073 ext4_std_error(sb, err);
1074out:
1075 iput(inode);
1076 ret = ERR_PTR(err);
1077really_out:
1078 brelse(inode_bitmap_bh);
1079 return ret;
1080
1081fail_free_drop:
1082 dquot_free_inode(inode);
1083
1084fail_drop:
1085 dquot_drop(inode);
1086 inode->i_flags |= S_NOQUOTA;
1087 inode->i_nlink = 0;
1088 unlock_new_inode(inode);
1089 iput(inode);
1090 brelse(inode_bitmap_bh);
1091 return ERR_PTR(err);
1092}
1093
1094/* Verify that we are loading a valid orphan from disk */
1095struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1096{
1097 unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1098 ext4_group_t block_group;
1099 int bit;
1100 struct buffer_head *bitmap_bh;
1101 struct inode *inode = NULL;
1102 long err = -EIO;
1103
1104 /* Error cases - e2fsck has already cleaned up for us */
1105 if (ino > max_ino) {
1106 ext4_warning(sb, "bad orphan ino %lu! e2fsck was run?", ino);
1107 goto error;
1108 }
1109
1110 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1111 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1112 bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1113 if (!bitmap_bh) {
1114 ext4_warning(sb, "inode bitmap error for orphan %lu", ino);
1115 goto error;
1116 }
1117
1118 /* Having the inode bit set should be a 100% indicator that this
1119 * is a valid orphan (no e2fsck run on fs). Orphans also include
1120 * inodes that were being truncated, so we can't check i_nlink==0.
1121 */
1122 if (!ext4_test_bit(bit, bitmap_bh->b_data))
1123 goto bad_orphan;
1124
1125 inode = ext4_iget(sb, ino);
1126 if (IS_ERR(inode))
1127 goto iget_failed;
1128
1129 /*
1130 * If the orphans has i_nlinks > 0 then it should be able to be
1131 * truncated, otherwise it won't be removed from the orphan list
1132 * during processing and an infinite loop will result.
1133 */
1134 if (inode->i_nlink && !ext4_can_truncate(inode))
1135 goto bad_orphan;
1136
1137 if (NEXT_ORPHAN(inode) > max_ino)
1138 goto bad_orphan;
1139 brelse(bitmap_bh);
1140 return inode;
1141
1142iget_failed:
1143 err = PTR_ERR(inode);
1144 inode = NULL;
1145bad_orphan:
1146 ext4_warning(sb, "bad orphan inode %lu! e2fsck was run?", ino);
1147 printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1148 bit, (unsigned long long)bitmap_bh->b_blocknr,
1149 ext4_test_bit(bit, bitmap_bh->b_data));
1150 printk(KERN_NOTICE "inode=%p\n", inode);
1151 if (inode) {
1152 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
1153 is_bad_inode(inode));
1154 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
1155 NEXT_ORPHAN(inode));
1156 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
1157 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
1158 /* Avoid freeing blocks if we got a bad deleted inode */
1159 if (inode->i_nlink == 0)
1160 inode->i_blocks = 0;
1161 iput(inode);
1162 }
1163 brelse(bitmap_bh);
1164error:
1165 return ERR_PTR(err);
1166}
1167
1168unsigned long ext4_count_free_inodes(struct super_block *sb)
1169{
1170 unsigned long desc_count;
1171 struct ext4_group_desc *gdp;
1172 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1173#ifdef EXT4FS_DEBUG
1174 struct ext4_super_block *es;
1175 unsigned long bitmap_count, x;
1176 struct buffer_head *bitmap_bh = NULL;
1177
1178 es = EXT4_SB(sb)->s_es;
1179 desc_count = 0;
1180 bitmap_count = 0;
1181 gdp = NULL;
1182 for (i = 0; i < ngroups; i++) {
1183 gdp = ext4_get_group_desc(sb, i, NULL);
1184 if (!gdp)
1185 continue;
1186 desc_count += ext4_free_inodes_count(sb, gdp);
1187 brelse(bitmap_bh);
1188 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1189 if (!bitmap_bh)
1190 continue;
1191
1192 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
1193 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1194 (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1195 bitmap_count += x;
1196 }
1197 brelse(bitmap_bh);
1198 printk(KERN_DEBUG "ext4_count_free_inodes: "
1199 "stored = %u, computed = %lu, %lu\n",
1200 le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1201 return desc_count;
1202#else
1203 desc_count = 0;
1204 for (i = 0; i < ngroups; i++) {
1205 gdp = ext4_get_group_desc(sb, i, NULL);
1206 if (!gdp)
1207 continue;
1208 desc_count += ext4_free_inodes_count(sb, gdp);
1209 cond_resched();
1210 }
1211 return desc_count;
1212#endif
1213}
1214
1215/* Called at mount-time, super-block is locked */
1216unsigned long ext4_count_dirs(struct super_block * sb)
1217{
1218 unsigned long count = 0;
1219 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1220
1221 for (i = 0; i < ngroups; i++) {
1222 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1223 if (!gdp)
1224 continue;
1225 count += ext4_used_dirs_count(sb, gdp);
1226 }
1227 return count;
1228}
1229
1230/*
1231 * Zeroes not yet zeroed inode table - just write zeroes through the whole
1232 * inode table. Must be called without any spinlock held. The only place
1233 * where it is called from on active part of filesystem is ext4lazyinit
1234 * thread, so we do not need any special locks, however we have to prevent
1235 * inode allocation from the current group, so we take alloc_sem lock, to
1236 * block ext4_claim_inode until we are finished.
1237 */
1238extern int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1239 int barrier)
1240{
1241 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1242 struct ext4_sb_info *sbi = EXT4_SB(sb);
1243 struct ext4_group_desc *gdp = NULL;
1244 struct buffer_head *group_desc_bh;
1245 handle_t *handle;
1246 ext4_fsblk_t blk;
1247 int num, ret = 0, used_blks = 0;
1248
1249 /* This should not happen, but just to be sure check this */
1250 if (sb->s_flags & MS_RDONLY) {
1251 ret = 1;
1252 goto out;
1253 }
1254
1255 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1256 if (!gdp)
1257 goto out;
1258
1259 /*
1260 * We do not need to lock this, because we are the only one
1261 * handling this flag.
1262 */
1263 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1264 goto out;
1265
1266 handle = ext4_journal_start_sb(sb, 1);
1267 if (IS_ERR(handle)) {
1268 ret = PTR_ERR(handle);
1269 goto out;
1270 }
1271
1272 down_write(&grp->alloc_sem);
1273 /*
1274 * If inode bitmap was already initialized there may be some
1275 * used inodes so we need to skip blocks with used inodes in
1276 * inode table.
1277 */
1278 if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1279 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1280 ext4_itable_unused_count(sb, gdp)),
1281 sbi->s_inodes_per_block);
1282
1283 if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1284 ext4_error(sb, "Something is wrong with group %u\n"
1285 "Used itable blocks: %d"
1286 "itable unused count: %u\n",
1287 group, used_blks,
1288 ext4_itable_unused_count(sb, gdp));
1289 ret = 1;
1290 goto err_out;
1291 }
1292
1293 blk = ext4_inode_table(sb, gdp) + used_blks;
1294 num = sbi->s_itb_per_group - used_blks;
1295
1296 BUFFER_TRACE(group_desc_bh, "get_write_access");
1297 ret = ext4_journal_get_write_access(handle,
1298 group_desc_bh);
1299 if (ret)
1300 goto err_out;
1301
1302 /*
1303 * Skip zeroout if the inode table is full. But we set the ZEROED
1304 * flag anyway, because obviously, when it is full it does not need
1305 * further zeroing.
1306 */
1307 if (unlikely(num == 0))
1308 goto skip_zeroout;
1309
1310 ext4_debug("going to zero out inode table in group %d\n",
1311 group);
1312 ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1313 if (ret < 0)
1314 goto err_out;
1315 if (barrier)
1316 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1317
1318skip_zeroout:
1319 ext4_lock_group(sb, group);
1320 gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1321 gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
1322 ext4_unlock_group(sb, group);
1323
1324 BUFFER_TRACE(group_desc_bh,
1325 "call ext4_handle_dirty_metadata");
1326 ret = ext4_handle_dirty_metadata(handle, NULL,
1327 group_desc_bh);
1328
1329err_out:
1330 up_write(&grp->alloc_sem);
1331 ext4_journal_stop(handle);
1332out:
1333 return ret;
1334}
1/*
2 * linux/fs/ext4/ialloc.c
3 *
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)
8 *
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
13 */
14
15#include <linux/time.h>
16#include <linux/fs.h>
17#include <linux/stat.h>
18#include <linux/string.h>
19#include <linux/quotaops.h>
20#include <linux/buffer_head.h>
21#include <linux/random.h>
22#include <linux/bitops.h>
23#include <linux/blkdev.h>
24#include <asm/byteorder.h>
25
26#include "ext4.h"
27#include "ext4_jbd2.h"
28#include "xattr.h"
29#include "acl.h"
30
31#include <trace/events/ext4.h>
32
33/*
34 * ialloc.c contains the inodes allocation and deallocation routines
35 */
36
37/*
38 * The free inodes are managed by bitmaps. A file system contains several
39 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
40 * block for inodes, N blocks for the inode table and data blocks.
41 *
42 * The file system contains group descriptors which are located after the
43 * super block. Each descriptor contains the number of the bitmap block and
44 * the free blocks count in the block.
45 */
46
47/*
48 * To avoid calling the atomic setbit hundreds or thousands of times, we only
49 * need to use it within a single byte (to ensure we get endianness right).
50 * We can use memset for the rest of the bitmap as there are no other users.
51 */
52void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
53{
54 int i;
55
56 if (start_bit >= end_bit)
57 return;
58
59 ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
60 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
61 ext4_set_bit(i, bitmap);
62 if (i < end_bit)
63 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
64}
65
66/* Initializes an uninitialized inode bitmap */
67static int ext4_init_inode_bitmap(struct super_block *sb,
68 struct buffer_head *bh,
69 ext4_group_t block_group,
70 struct ext4_group_desc *gdp)
71{
72 struct ext4_group_info *grp;
73 struct ext4_sb_info *sbi = EXT4_SB(sb);
74 J_ASSERT_BH(bh, buffer_locked(bh));
75
76 /* If checksum is bad mark all blocks and inodes use to prevent
77 * allocation, essentially implementing a per-group read-only flag. */
78 if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
79 grp = ext4_get_group_info(sb, block_group);
80 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
81 percpu_counter_sub(&sbi->s_freeclusters_counter,
82 grp->bb_free);
83 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
84 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
85 int count;
86 count = ext4_free_inodes_count(sb, gdp);
87 percpu_counter_sub(&sbi->s_freeinodes_counter,
88 count);
89 }
90 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
91 return -EFSBADCRC;
92 }
93
94 memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
95 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
96 bh->b_data);
97 ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
98 EXT4_INODES_PER_GROUP(sb) / 8);
99 ext4_group_desc_csum_set(sb, block_group, gdp);
100
101 return 0;
102}
103
104void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
105{
106 if (uptodate) {
107 set_buffer_uptodate(bh);
108 set_bitmap_uptodate(bh);
109 }
110 unlock_buffer(bh);
111 put_bh(bh);
112}
113
114static int ext4_validate_inode_bitmap(struct super_block *sb,
115 struct ext4_group_desc *desc,
116 ext4_group_t block_group,
117 struct buffer_head *bh)
118{
119 ext4_fsblk_t blk;
120 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
121 struct ext4_sb_info *sbi = EXT4_SB(sb);
122
123 if (buffer_verified(bh))
124 return 0;
125 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
126 return -EFSCORRUPTED;
127
128 ext4_lock_group(sb, block_group);
129 blk = ext4_inode_bitmap(sb, desc);
130 if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
131 EXT4_INODES_PER_GROUP(sb) / 8)) {
132 ext4_unlock_group(sb, block_group);
133 ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
134 "inode_bitmap = %llu", block_group, blk);
135 grp = ext4_get_group_info(sb, block_group);
136 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
137 int count;
138 count = ext4_free_inodes_count(sb, desc);
139 percpu_counter_sub(&sbi->s_freeinodes_counter,
140 count);
141 }
142 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
143 return -EFSBADCRC;
144 }
145 set_buffer_verified(bh);
146 ext4_unlock_group(sb, block_group);
147 return 0;
148}
149
150/*
151 * Read the inode allocation bitmap for a given block_group, reading
152 * into the specified slot in the superblock's bitmap cache.
153 *
154 * Return buffer_head of bitmap on success or NULL.
155 */
156static struct buffer_head *
157ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
158{
159 struct ext4_group_desc *desc;
160 struct buffer_head *bh = NULL;
161 ext4_fsblk_t bitmap_blk;
162 int err;
163
164 desc = ext4_get_group_desc(sb, block_group, NULL);
165 if (!desc)
166 return ERR_PTR(-EFSCORRUPTED);
167
168 bitmap_blk = ext4_inode_bitmap(sb, desc);
169 bh = sb_getblk(sb, bitmap_blk);
170 if (unlikely(!bh)) {
171 ext4_error(sb, "Cannot read inode bitmap - "
172 "block_group = %u, inode_bitmap = %llu",
173 block_group, bitmap_blk);
174 return ERR_PTR(-EIO);
175 }
176 if (bitmap_uptodate(bh))
177 goto verify;
178
179 lock_buffer(bh);
180 if (bitmap_uptodate(bh)) {
181 unlock_buffer(bh);
182 goto verify;
183 }
184
185 ext4_lock_group(sb, block_group);
186 if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
187 err = ext4_init_inode_bitmap(sb, bh, block_group, desc);
188 set_bitmap_uptodate(bh);
189 set_buffer_uptodate(bh);
190 set_buffer_verified(bh);
191 ext4_unlock_group(sb, block_group);
192 unlock_buffer(bh);
193 if (err) {
194 ext4_error(sb, "Failed to init inode bitmap for group "
195 "%u: %d", block_group, err);
196 goto out;
197 }
198 return bh;
199 }
200 ext4_unlock_group(sb, block_group);
201
202 if (buffer_uptodate(bh)) {
203 /*
204 * if not uninit if bh is uptodate,
205 * bitmap is also uptodate
206 */
207 set_bitmap_uptodate(bh);
208 unlock_buffer(bh);
209 goto verify;
210 }
211 /*
212 * submit the buffer_head for reading
213 */
214 trace_ext4_load_inode_bitmap(sb, block_group);
215 bh->b_end_io = ext4_end_bitmap_read;
216 get_bh(bh);
217 submit_bh(READ | REQ_META | REQ_PRIO, bh);
218 wait_on_buffer(bh);
219 if (!buffer_uptodate(bh)) {
220 put_bh(bh);
221 ext4_error(sb, "Cannot read inode bitmap - "
222 "block_group = %u, inode_bitmap = %llu",
223 block_group, bitmap_blk);
224 return ERR_PTR(-EIO);
225 }
226
227verify:
228 err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
229 if (err)
230 goto out;
231 return bh;
232out:
233 put_bh(bh);
234 return ERR_PTR(err);
235}
236
237/*
238 * NOTE! When we get the inode, we're the only people
239 * that have access to it, and as such there are no
240 * race conditions we have to worry about. The inode
241 * is not on the hash-lists, and it cannot be reached
242 * through the filesystem because the directory entry
243 * has been deleted earlier.
244 *
245 * HOWEVER: we must make sure that we get no aliases,
246 * which means that we have to call "clear_inode()"
247 * _before_ we mark the inode not in use in the inode
248 * bitmaps. Otherwise a newly created file might use
249 * the same inode number (not actually the same pointer
250 * though), and then we'd have two inodes sharing the
251 * same inode number and space on the harddisk.
252 */
253void ext4_free_inode(handle_t *handle, struct inode *inode)
254{
255 struct super_block *sb = inode->i_sb;
256 int is_directory;
257 unsigned long ino;
258 struct buffer_head *bitmap_bh = NULL;
259 struct buffer_head *bh2;
260 ext4_group_t block_group;
261 unsigned long bit;
262 struct ext4_group_desc *gdp;
263 struct ext4_super_block *es;
264 struct ext4_sb_info *sbi;
265 int fatal = 0, err, count, cleared;
266 struct ext4_group_info *grp;
267
268 if (!sb) {
269 printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
270 "nonexistent device\n", __func__, __LINE__);
271 return;
272 }
273 if (atomic_read(&inode->i_count) > 1) {
274 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
275 __func__, __LINE__, inode->i_ino,
276 atomic_read(&inode->i_count));
277 return;
278 }
279 if (inode->i_nlink) {
280 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
281 __func__, __LINE__, inode->i_ino, inode->i_nlink);
282 return;
283 }
284 sbi = EXT4_SB(sb);
285
286 ino = inode->i_ino;
287 ext4_debug("freeing inode %lu\n", ino);
288 trace_ext4_free_inode(inode);
289
290 /*
291 * Note: we must free any quota before locking the superblock,
292 * as writing the quota to disk may need the lock as well.
293 */
294 dquot_initialize(inode);
295 ext4_xattr_delete_inode(handle, inode);
296 dquot_free_inode(inode);
297 dquot_drop(inode);
298
299 is_directory = S_ISDIR(inode->i_mode);
300
301 /* Do this BEFORE marking the inode not in use or returning an error */
302 ext4_clear_inode(inode);
303
304 es = EXT4_SB(sb)->s_es;
305 if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
306 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
307 goto error_return;
308 }
309 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
310 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
311 bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
312 /* Don't bother if the inode bitmap is corrupt. */
313 grp = ext4_get_group_info(sb, block_group);
314 if (IS_ERR(bitmap_bh)) {
315 fatal = PTR_ERR(bitmap_bh);
316 bitmap_bh = NULL;
317 goto error_return;
318 }
319 if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
320 fatal = -EFSCORRUPTED;
321 goto error_return;
322 }
323
324 BUFFER_TRACE(bitmap_bh, "get_write_access");
325 fatal = ext4_journal_get_write_access(handle, bitmap_bh);
326 if (fatal)
327 goto error_return;
328
329 fatal = -ESRCH;
330 gdp = ext4_get_group_desc(sb, block_group, &bh2);
331 if (gdp) {
332 BUFFER_TRACE(bh2, "get_write_access");
333 fatal = ext4_journal_get_write_access(handle, bh2);
334 }
335 ext4_lock_group(sb, block_group);
336 cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
337 if (fatal || !cleared) {
338 ext4_unlock_group(sb, block_group);
339 goto out;
340 }
341
342 count = ext4_free_inodes_count(sb, gdp) + 1;
343 ext4_free_inodes_set(sb, gdp, count);
344 if (is_directory) {
345 count = ext4_used_dirs_count(sb, gdp) - 1;
346 ext4_used_dirs_set(sb, gdp, count);
347 percpu_counter_dec(&sbi->s_dirs_counter);
348 }
349 ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
350 EXT4_INODES_PER_GROUP(sb) / 8);
351 ext4_group_desc_csum_set(sb, block_group, gdp);
352 ext4_unlock_group(sb, block_group);
353
354 percpu_counter_inc(&sbi->s_freeinodes_counter);
355 if (sbi->s_log_groups_per_flex) {
356 ext4_group_t f = ext4_flex_group(sbi, block_group);
357
358 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
359 if (is_directory)
360 atomic_dec(&sbi->s_flex_groups[f].used_dirs);
361 }
362 BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
363 fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
364out:
365 if (cleared) {
366 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
367 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
368 if (!fatal)
369 fatal = err;
370 } else {
371 ext4_error(sb, "bit already cleared for inode %lu", ino);
372 if (gdp && !EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
373 int count;
374 count = ext4_free_inodes_count(sb, gdp);
375 percpu_counter_sub(&sbi->s_freeinodes_counter,
376 count);
377 }
378 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
379 }
380
381error_return:
382 brelse(bitmap_bh);
383 ext4_std_error(sb, fatal);
384}
385
386struct orlov_stats {
387 __u64 free_clusters;
388 __u32 free_inodes;
389 __u32 used_dirs;
390};
391
392/*
393 * Helper function for Orlov's allocator; returns critical information
394 * for a particular block group or flex_bg. If flex_size is 1, then g
395 * is a block group number; otherwise it is flex_bg number.
396 */
397static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
398 int flex_size, struct orlov_stats *stats)
399{
400 struct ext4_group_desc *desc;
401 struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
402
403 if (flex_size > 1) {
404 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
405 stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
406 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
407 return;
408 }
409
410 desc = ext4_get_group_desc(sb, g, NULL);
411 if (desc) {
412 stats->free_inodes = ext4_free_inodes_count(sb, desc);
413 stats->free_clusters = ext4_free_group_clusters(sb, desc);
414 stats->used_dirs = ext4_used_dirs_count(sb, desc);
415 } else {
416 stats->free_inodes = 0;
417 stats->free_clusters = 0;
418 stats->used_dirs = 0;
419 }
420}
421
422/*
423 * Orlov's allocator for directories.
424 *
425 * We always try to spread first-level directories.
426 *
427 * If there are blockgroups with both free inodes and free blocks counts
428 * not worse than average we return one with smallest directory count.
429 * Otherwise we simply return a random group.
430 *
431 * For the rest rules look so:
432 *
433 * It's OK to put directory into a group unless
434 * it has too many directories already (max_dirs) or
435 * it has too few free inodes left (min_inodes) or
436 * it has too few free blocks left (min_blocks) or
437 * Parent's group is preferred, if it doesn't satisfy these
438 * conditions we search cyclically through the rest. If none
439 * of the groups look good we just look for a group with more
440 * free inodes than average (starting at parent's group).
441 */
442
443static int find_group_orlov(struct super_block *sb, struct inode *parent,
444 ext4_group_t *group, umode_t mode,
445 const struct qstr *qstr)
446{
447 ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
448 struct ext4_sb_info *sbi = EXT4_SB(sb);
449 ext4_group_t real_ngroups = ext4_get_groups_count(sb);
450 int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
451 unsigned int freei, avefreei, grp_free;
452 ext4_fsblk_t freeb, avefreec;
453 unsigned int ndirs;
454 int max_dirs, min_inodes;
455 ext4_grpblk_t min_clusters;
456 ext4_group_t i, grp, g, ngroups;
457 struct ext4_group_desc *desc;
458 struct orlov_stats stats;
459 int flex_size = ext4_flex_bg_size(sbi);
460 struct dx_hash_info hinfo;
461
462 ngroups = real_ngroups;
463 if (flex_size > 1) {
464 ngroups = (real_ngroups + flex_size - 1) >>
465 sbi->s_log_groups_per_flex;
466 parent_group >>= sbi->s_log_groups_per_flex;
467 }
468
469 freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
470 avefreei = freei / ngroups;
471 freeb = EXT4_C2B(sbi,
472 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
473 avefreec = freeb;
474 do_div(avefreec, ngroups);
475 ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
476
477 if (S_ISDIR(mode) &&
478 ((parent == d_inode(sb->s_root)) ||
479 (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
480 int best_ndir = inodes_per_group;
481 int ret = -1;
482
483 if (qstr) {
484 hinfo.hash_version = DX_HASH_HALF_MD4;
485 hinfo.seed = sbi->s_hash_seed;
486 ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
487 grp = hinfo.hash;
488 } else
489 grp = prandom_u32();
490 parent_group = (unsigned)grp % ngroups;
491 for (i = 0; i < ngroups; i++) {
492 g = (parent_group + i) % ngroups;
493 get_orlov_stats(sb, g, flex_size, &stats);
494 if (!stats.free_inodes)
495 continue;
496 if (stats.used_dirs >= best_ndir)
497 continue;
498 if (stats.free_inodes < avefreei)
499 continue;
500 if (stats.free_clusters < avefreec)
501 continue;
502 grp = g;
503 ret = 0;
504 best_ndir = stats.used_dirs;
505 }
506 if (ret)
507 goto fallback;
508 found_flex_bg:
509 if (flex_size == 1) {
510 *group = grp;
511 return 0;
512 }
513
514 /*
515 * We pack inodes at the beginning of the flexgroup's
516 * inode tables. Block allocation decisions will do
517 * something similar, although regular files will
518 * start at 2nd block group of the flexgroup. See
519 * ext4_ext_find_goal() and ext4_find_near().
520 */
521 grp *= flex_size;
522 for (i = 0; i < flex_size; i++) {
523 if (grp+i >= real_ngroups)
524 break;
525 desc = ext4_get_group_desc(sb, grp+i, NULL);
526 if (desc && ext4_free_inodes_count(sb, desc)) {
527 *group = grp+i;
528 return 0;
529 }
530 }
531 goto fallback;
532 }
533
534 max_dirs = ndirs / ngroups + inodes_per_group / 16;
535 min_inodes = avefreei - inodes_per_group*flex_size / 4;
536 if (min_inodes < 1)
537 min_inodes = 1;
538 min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
539
540 /*
541 * Start looking in the flex group where we last allocated an
542 * inode for this parent directory
543 */
544 if (EXT4_I(parent)->i_last_alloc_group != ~0) {
545 parent_group = EXT4_I(parent)->i_last_alloc_group;
546 if (flex_size > 1)
547 parent_group >>= sbi->s_log_groups_per_flex;
548 }
549
550 for (i = 0; i < ngroups; i++) {
551 grp = (parent_group + i) % ngroups;
552 get_orlov_stats(sb, grp, flex_size, &stats);
553 if (stats.used_dirs >= max_dirs)
554 continue;
555 if (stats.free_inodes < min_inodes)
556 continue;
557 if (stats.free_clusters < min_clusters)
558 continue;
559 goto found_flex_bg;
560 }
561
562fallback:
563 ngroups = real_ngroups;
564 avefreei = freei / ngroups;
565fallback_retry:
566 parent_group = EXT4_I(parent)->i_block_group;
567 for (i = 0; i < ngroups; i++) {
568 grp = (parent_group + i) % ngroups;
569 desc = ext4_get_group_desc(sb, grp, NULL);
570 if (desc) {
571 grp_free = ext4_free_inodes_count(sb, desc);
572 if (grp_free && grp_free >= avefreei) {
573 *group = grp;
574 return 0;
575 }
576 }
577 }
578
579 if (avefreei) {
580 /*
581 * The free-inodes counter is approximate, and for really small
582 * filesystems the above test can fail to find any blockgroups
583 */
584 avefreei = 0;
585 goto fallback_retry;
586 }
587
588 return -1;
589}
590
591static int find_group_other(struct super_block *sb, struct inode *parent,
592 ext4_group_t *group, umode_t mode)
593{
594 ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
595 ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
596 struct ext4_group_desc *desc;
597 int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
598
599 /*
600 * Try to place the inode is the same flex group as its
601 * parent. If we can't find space, use the Orlov algorithm to
602 * find another flex group, and store that information in the
603 * parent directory's inode information so that use that flex
604 * group for future allocations.
605 */
606 if (flex_size > 1) {
607 int retry = 0;
608
609 try_again:
610 parent_group &= ~(flex_size-1);
611 last = parent_group + flex_size;
612 if (last > ngroups)
613 last = ngroups;
614 for (i = parent_group; i < last; i++) {
615 desc = ext4_get_group_desc(sb, i, NULL);
616 if (desc && ext4_free_inodes_count(sb, desc)) {
617 *group = i;
618 return 0;
619 }
620 }
621 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
622 retry = 1;
623 parent_group = EXT4_I(parent)->i_last_alloc_group;
624 goto try_again;
625 }
626 /*
627 * If this didn't work, use the Orlov search algorithm
628 * to find a new flex group; we pass in the mode to
629 * avoid the topdir algorithms.
630 */
631 *group = parent_group + flex_size;
632 if (*group > ngroups)
633 *group = 0;
634 return find_group_orlov(sb, parent, group, mode, NULL);
635 }
636
637 /*
638 * Try to place the inode in its parent directory
639 */
640 *group = parent_group;
641 desc = ext4_get_group_desc(sb, *group, NULL);
642 if (desc && ext4_free_inodes_count(sb, desc) &&
643 ext4_free_group_clusters(sb, desc))
644 return 0;
645
646 /*
647 * We're going to place this inode in a different blockgroup from its
648 * parent. We want to cause files in a common directory to all land in
649 * the same blockgroup. But we want files which are in a different
650 * directory which shares a blockgroup with our parent to land in a
651 * different blockgroup.
652 *
653 * So add our directory's i_ino into the starting point for the hash.
654 */
655 *group = (*group + parent->i_ino) % ngroups;
656
657 /*
658 * Use a quadratic hash to find a group with a free inode and some free
659 * blocks.
660 */
661 for (i = 1; i < ngroups; i <<= 1) {
662 *group += i;
663 if (*group >= ngroups)
664 *group -= ngroups;
665 desc = ext4_get_group_desc(sb, *group, NULL);
666 if (desc && ext4_free_inodes_count(sb, desc) &&
667 ext4_free_group_clusters(sb, desc))
668 return 0;
669 }
670
671 /*
672 * That failed: try linear search for a free inode, even if that group
673 * has no free blocks.
674 */
675 *group = parent_group;
676 for (i = 0; i < ngroups; i++) {
677 if (++*group >= ngroups)
678 *group = 0;
679 desc = ext4_get_group_desc(sb, *group, NULL);
680 if (desc && ext4_free_inodes_count(sb, desc))
681 return 0;
682 }
683
684 return -1;
685}
686
687/*
688 * In no journal mode, if an inode has recently been deleted, we want
689 * to avoid reusing it until we're reasonably sure the inode table
690 * block has been written back to disk. (Yes, these values are
691 * somewhat arbitrary...)
692 */
693#define RECENTCY_MIN 5
694#define RECENTCY_DIRTY 30
695
696static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
697{
698 struct ext4_group_desc *gdp;
699 struct ext4_inode *raw_inode;
700 struct buffer_head *bh;
701 unsigned long dtime, now;
702 int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
703 int offset, ret = 0, recentcy = RECENTCY_MIN;
704
705 gdp = ext4_get_group_desc(sb, group, NULL);
706 if (unlikely(!gdp))
707 return 0;
708
709 bh = sb_getblk(sb, ext4_inode_table(sb, gdp) +
710 (ino / inodes_per_block));
711 if (unlikely(!bh) || !buffer_uptodate(bh))
712 /*
713 * If the block is not in the buffer cache, then it
714 * must have been written out.
715 */
716 goto out;
717
718 offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
719 raw_inode = (struct ext4_inode *) (bh->b_data + offset);
720 dtime = le32_to_cpu(raw_inode->i_dtime);
721 now = get_seconds();
722 if (buffer_dirty(bh))
723 recentcy += RECENTCY_DIRTY;
724
725 if (dtime && (dtime < now) && (now < dtime + recentcy))
726 ret = 1;
727out:
728 brelse(bh);
729 return ret;
730}
731
732/*
733 * There are two policies for allocating an inode. If the new inode is
734 * a directory, then a forward search is made for a block group with both
735 * free space and a low directory-to-inode ratio; if that fails, then of
736 * the groups with above-average free space, that group with the fewest
737 * directories already is chosen.
738 *
739 * For other inodes, search forward from the parent directory's block
740 * group to find a free inode.
741 */
742struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
743 umode_t mode, const struct qstr *qstr,
744 __u32 goal, uid_t *owner, int handle_type,
745 unsigned int line_no, int nblocks)
746{
747 struct super_block *sb;
748 struct buffer_head *inode_bitmap_bh = NULL;
749 struct buffer_head *group_desc_bh;
750 ext4_group_t ngroups, group = 0;
751 unsigned long ino = 0;
752 struct inode *inode;
753 struct ext4_group_desc *gdp = NULL;
754 struct ext4_inode_info *ei;
755 struct ext4_sb_info *sbi;
756 int ret2, err;
757 struct inode *ret;
758 ext4_group_t i;
759 ext4_group_t flex_group;
760 struct ext4_group_info *grp;
761 int encrypt = 0;
762
763 /* Cannot create files in a deleted directory */
764 if (!dir || !dir->i_nlink)
765 return ERR_PTR(-EPERM);
766
767 if ((ext4_encrypted_inode(dir) ||
768 DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb))) &&
769 (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
770 err = ext4_get_encryption_info(dir);
771 if (err)
772 return ERR_PTR(err);
773 if (ext4_encryption_info(dir) == NULL)
774 return ERR_PTR(-EPERM);
775 if (!handle)
776 nblocks += EXT4_DATA_TRANS_BLOCKS(dir->i_sb);
777 encrypt = 1;
778 }
779
780 sb = dir->i_sb;
781 ngroups = ext4_get_groups_count(sb);
782 trace_ext4_request_inode(dir, mode);
783 inode = new_inode(sb);
784 if (!inode)
785 return ERR_PTR(-ENOMEM);
786 ei = EXT4_I(inode);
787 sbi = EXT4_SB(sb);
788
789 /*
790 * Initialize owners and quota early so that we don't have to account
791 * for quota initialization worst case in standard inode creating
792 * transaction
793 */
794 if (owner) {
795 inode->i_mode = mode;
796 i_uid_write(inode, owner[0]);
797 i_gid_write(inode, owner[1]);
798 } else if (test_opt(sb, GRPID)) {
799 inode->i_mode = mode;
800 inode->i_uid = current_fsuid();
801 inode->i_gid = dir->i_gid;
802 } else
803 inode_init_owner(inode, dir, mode);
804
805 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_PROJECT) &&
806 ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
807 ei->i_projid = EXT4_I(dir)->i_projid;
808 else
809 ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
810
811 err = dquot_initialize(inode);
812 if (err)
813 goto out;
814
815 if (!goal)
816 goal = sbi->s_inode_goal;
817
818 if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
819 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
820 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
821 ret2 = 0;
822 goto got_group;
823 }
824
825 if (S_ISDIR(mode))
826 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
827 else
828 ret2 = find_group_other(sb, dir, &group, mode);
829
830got_group:
831 EXT4_I(dir)->i_last_alloc_group = group;
832 err = -ENOSPC;
833 if (ret2 == -1)
834 goto out;
835
836 /*
837 * Normally we will only go through one pass of this loop,
838 * unless we get unlucky and it turns out the group we selected
839 * had its last inode grabbed by someone else.
840 */
841 for (i = 0; i < ngroups; i++, ino = 0) {
842 err = -EIO;
843
844 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
845 if (!gdp)
846 goto out;
847
848 /*
849 * Check free inodes count before loading bitmap.
850 */
851 if (ext4_free_inodes_count(sb, gdp) == 0) {
852 if (++group == ngroups)
853 group = 0;
854 continue;
855 }
856
857 grp = ext4_get_group_info(sb, group);
858 /* Skip groups with already-known suspicious inode tables */
859 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
860 if (++group == ngroups)
861 group = 0;
862 continue;
863 }
864
865 brelse(inode_bitmap_bh);
866 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
867 /* Skip groups with suspicious inode tables */
868 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
869 IS_ERR(inode_bitmap_bh)) {
870 inode_bitmap_bh = NULL;
871 if (++group == ngroups)
872 group = 0;
873 continue;
874 }
875
876repeat_in_this_group:
877 ino = ext4_find_next_zero_bit((unsigned long *)
878 inode_bitmap_bh->b_data,
879 EXT4_INODES_PER_GROUP(sb), ino);
880 if (ino >= EXT4_INODES_PER_GROUP(sb))
881 goto next_group;
882 if (group == 0 && (ino+1) < EXT4_FIRST_INO(sb)) {
883 ext4_error(sb, "reserved inode found cleared - "
884 "inode=%lu", ino + 1);
885 continue;
886 }
887 if ((EXT4_SB(sb)->s_journal == NULL) &&
888 recently_deleted(sb, group, ino)) {
889 ino++;
890 goto next_inode;
891 }
892 if (!handle) {
893 BUG_ON(nblocks <= 0);
894 handle = __ext4_journal_start_sb(dir->i_sb, line_no,
895 handle_type, nblocks,
896 0);
897 if (IS_ERR(handle)) {
898 err = PTR_ERR(handle);
899 ext4_std_error(sb, err);
900 goto out;
901 }
902 }
903 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
904 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
905 if (err) {
906 ext4_std_error(sb, err);
907 goto out;
908 }
909 ext4_lock_group(sb, group);
910 ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
911 ext4_unlock_group(sb, group);
912 ino++; /* the inode bitmap is zero-based */
913 if (!ret2)
914 goto got; /* we grabbed the inode! */
915next_inode:
916 if (ino < EXT4_INODES_PER_GROUP(sb))
917 goto repeat_in_this_group;
918next_group:
919 if (++group == ngroups)
920 group = 0;
921 }
922 err = -ENOSPC;
923 goto out;
924
925got:
926 BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
927 err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
928 if (err) {
929 ext4_std_error(sb, err);
930 goto out;
931 }
932
933 BUFFER_TRACE(group_desc_bh, "get_write_access");
934 err = ext4_journal_get_write_access(handle, group_desc_bh);
935 if (err) {
936 ext4_std_error(sb, err);
937 goto out;
938 }
939
940 /* We may have to initialize the block bitmap if it isn't already */
941 if (ext4_has_group_desc_csum(sb) &&
942 gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
943 struct buffer_head *block_bitmap_bh;
944
945 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
946 if (IS_ERR(block_bitmap_bh)) {
947 err = PTR_ERR(block_bitmap_bh);
948 goto out;
949 }
950 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
951 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
952 if (err) {
953 brelse(block_bitmap_bh);
954 ext4_std_error(sb, err);
955 goto out;
956 }
957
958 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
959 err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
960
961 /* recheck and clear flag under lock if we still need to */
962 ext4_lock_group(sb, group);
963 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
964 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
965 ext4_free_group_clusters_set(sb, gdp,
966 ext4_free_clusters_after_init(sb, group, gdp));
967 ext4_block_bitmap_csum_set(sb, group, gdp,
968 block_bitmap_bh);
969 ext4_group_desc_csum_set(sb, group, gdp);
970 }
971 ext4_unlock_group(sb, group);
972 brelse(block_bitmap_bh);
973
974 if (err) {
975 ext4_std_error(sb, err);
976 goto out;
977 }
978 }
979
980 /* Update the relevant bg descriptor fields */
981 if (ext4_has_group_desc_csum(sb)) {
982 int free;
983 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
984
985 down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
986 ext4_lock_group(sb, group); /* while we modify the bg desc */
987 free = EXT4_INODES_PER_GROUP(sb) -
988 ext4_itable_unused_count(sb, gdp);
989 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
990 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
991 free = 0;
992 }
993 /*
994 * Check the relative inode number against the last used
995 * relative inode number in this group. if it is greater
996 * we need to update the bg_itable_unused count
997 */
998 if (ino > free)
999 ext4_itable_unused_set(sb, gdp,
1000 (EXT4_INODES_PER_GROUP(sb) - ino));
1001 up_read(&grp->alloc_sem);
1002 } else {
1003 ext4_lock_group(sb, group);
1004 }
1005
1006 ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1007 if (S_ISDIR(mode)) {
1008 ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1009 if (sbi->s_log_groups_per_flex) {
1010 ext4_group_t f = ext4_flex_group(sbi, group);
1011
1012 atomic_inc(&sbi->s_flex_groups[f].used_dirs);
1013 }
1014 }
1015 if (ext4_has_group_desc_csum(sb)) {
1016 ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1017 EXT4_INODES_PER_GROUP(sb) / 8);
1018 ext4_group_desc_csum_set(sb, group, gdp);
1019 }
1020 ext4_unlock_group(sb, group);
1021
1022 BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1023 err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1024 if (err) {
1025 ext4_std_error(sb, err);
1026 goto out;
1027 }
1028
1029 percpu_counter_dec(&sbi->s_freeinodes_counter);
1030 if (S_ISDIR(mode))
1031 percpu_counter_inc(&sbi->s_dirs_counter);
1032
1033 if (sbi->s_log_groups_per_flex) {
1034 flex_group = ext4_flex_group(sbi, group);
1035 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
1036 }
1037
1038 inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1039 /* This is the optimal IO size (for stat), not the fs block size */
1040 inode->i_blocks = 0;
1041 inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
1042 ext4_current_time(inode);
1043
1044 memset(ei->i_data, 0, sizeof(ei->i_data));
1045 ei->i_dir_start_lookup = 0;
1046 ei->i_disksize = 0;
1047
1048 /* Don't inherit extent flag from directory, amongst others. */
1049 ei->i_flags =
1050 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1051 ei->i_file_acl = 0;
1052 ei->i_dtime = 0;
1053 ei->i_block_group = group;
1054 ei->i_last_alloc_group = ~0;
1055
1056 ext4_set_inode_flags(inode);
1057 if (IS_DIRSYNC(inode))
1058 ext4_handle_sync(handle);
1059 if (insert_inode_locked(inode) < 0) {
1060 /*
1061 * Likely a bitmap corruption causing inode to be allocated
1062 * twice.
1063 */
1064 err = -EIO;
1065 ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1066 inode->i_ino);
1067 goto out;
1068 }
1069 spin_lock(&sbi->s_next_gen_lock);
1070 inode->i_generation = sbi->s_next_generation++;
1071 spin_unlock(&sbi->s_next_gen_lock);
1072
1073 /* Precompute checksum seed for inode metadata */
1074 if (ext4_has_metadata_csum(sb)) {
1075 __u32 csum;
1076 __le32 inum = cpu_to_le32(inode->i_ino);
1077 __le32 gen = cpu_to_le32(inode->i_generation);
1078 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1079 sizeof(inum));
1080 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1081 sizeof(gen));
1082 }
1083
1084 ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1085 ext4_set_inode_state(inode, EXT4_STATE_NEW);
1086
1087 ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
1088 ei->i_inline_off = 0;
1089 if (ext4_has_feature_inline_data(sb))
1090 ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1091 ret = inode;
1092 err = dquot_alloc_inode(inode);
1093 if (err)
1094 goto fail_drop;
1095
1096 err = ext4_init_acl(handle, inode, dir);
1097 if (err)
1098 goto fail_free_drop;
1099
1100 err = ext4_init_security(handle, inode, dir, qstr);
1101 if (err)
1102 goto fail_free_drop;
1103
1104 if (ext4_has_feature_extents(sb)) {
1105 /* set extent flag only for directory, file and normal symlink*/
1106 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1107 ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1108 ext4_ext_tree_init(handle, inode);
1109 }
1110 }
1111
1112 if (ext4_handle_valid(handle)) {
1113 ei->i_sync_tid = handle->h_transaction->t_tid;
1114 ei->i_datasync_tid = handle->h_transaction->t_tid;
1115 }
1116
1117 if (encrypt) {
1118 err = ext4_inherit_context(dir, inode);
1119 if (err)
1120 goto fail_free_drop;
1121 }
1122
1123 err = ext4_mark_inode_dirty(handle, inode);
1124 if (err) {
1125 ext4_std_error(sb, err);
1126 goto fail_free_drop;
1127 }
1128
1129 ext4_debug("allocating inode %lu\n", inode->i_ino);
1130 trace_ext4_allocate_inode(inode, dir, mode);
1131 brelse(inode_bitmap_bh);
1132 return ret;
1133
1134fail_free_drop:
1135 dquot_free_inode(inode);
1136fail_drop:
1137 clear_nlink(inode);
1138 unlock_new_inode(inode);
1139out:
1140 dquot_drop(inode);
1141 inode->i_flags |= S_NOQUOTA;
1142 iput(inode);
1143 brelse(inode_bitmap_bh);
1144 return ERR_PTR(err);
1145}
1146
1147/* Verify that we are loading a valid orphan from disk */
1148struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1149{
1150 unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1151 ext4_group_t block_group;
1152 int bit;
1153 struct buffer_head *bitmap_bh;
1154 struct inode *inode = NULL;
1155 long err = -EIO;
1156
1157 /* Error cases - e2fsck has already cleaned up for us */
1158 if (ino > max_ino) {
1159 ext4_warning(sb, "bad orphan ino %lu! e2fsck was run?", ino);
1160 err = -EFSCORRUPTED;
1161 goto error;
1162 }
1163
1164 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1165 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1166 bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1167 if (IS_ERR(bitmap_bh)) {
1168 err = PTR_ERR(bitmap_bh);
1169 ext4_warning(sb, "inode bitmap error %ld for orphan %lu",
1170 ino, err);
1171 goto error;
1172 }
1173
1174 /* Having the inode bit set should be a 100% indicator that this
1175 * is a valid orphan (no e2fsck run on fs). Orphans also include
1176 * inodes that were being truncated, so we can't check i_nlink==0.
1177 */
1178 if (!ext4_test_bit(bit, bitmap_bh->b_data))
1179 goto bad_orphan;
1180
1181 inode = ext4_iget(sb, ino);
1182 if (IS_ERR(inode))
1183 goto iget_failed;
1184
1185 /*
1186 * If the orphans has i_nlinks > 0 then it should be able to be
1187 * truncated, otherwise it won't be removed from the orphan list
1188 * during processing and an infinite loop will result.
1189 */
1190 if (inode->i_nlink && !ext4_can_truncate(inode))
1191 goto bad_orphan;
1192
1193 if (NEXT_ORPHAN(inode) > max_ino)
1194 goto bad_orphan;
1195 brelse(bitmap_bh);
1196 return inode;
1197
1198iget_failed:
1199 err = PTR_ERR(inode);
1200 inode = NULL;
1201bad_orphan:
1202 ext4_warning(sb, "bad orphan inode %lu! e2fsck was run?", ino);
1203 printk(KERN_WARNING "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1204 bit, (unsigned long long)bitmap_bh->b_blocknr,
1205 ext4_test_bit(bit, bitmap_bh->b_data));
1206 printk(KERN_WARNING "inode=%p\n", inode);
1207 if (inode) {
1208 printk(KERN_WARNING "is_bad_inode(inode)=%d\n",
1209 is_bad_inode(inode));
1210 printk(KERN_WARNING "NEXT_ORPHAN(inode)=%u\n",
1211 NEXT_ORPHAN(inode));
1212 printk(KERN_WARNING "max_ino=%lu\n", max_ino);
1213 printk(KERN_WARNING "i_nlink=%u\n", inode->i_nlink);
1214 /* Avoid freeing blocks if we got a bad deleted inode */
1215 if (inode->i_nlink == 0)
1216 inode->i_blocks = 0;
1217 iput(inode);
1218 }
1219 brelse(bitmap_bh);
1220error:
1221 return ERR_PTR(err);
1222}
1223
1224unsigned long ext4_count_free_inodes(struct super_block *sb)
1225{
1226 unsigned long desc_count;
1227 struct ext4_group_desc *gdp;
1228 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1229#ifdef EXT4FS_DEBUG
1230 struct ext4_super_block *es;
1231 unsigned long bitmap_count, x;
1232 struct buffer_head *bitmap_bh = NULL;
1233
1234 es = EXT4_SB(sb)->s_es;
1235 desc_count = 0;
1236 bitmap_count = 0;
1237 gdp = NULL;
1238 for (i = 0; i < ngroups; i++) {
1239 gdp = ext4_get_group_desc(sb, i, NULL);
1240 if (!gdp)
1241 continue;
1242 desc_count += ext4_free_inodes_count(sb, gdp);
1243 brelse(bitmap_bh);
1244 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1245 if (IS_ERR(bitmap_bh)) {
1246 bitmap_bh = NULL;
1247 continue;
1248 }
1249
1250 x = ext4_count_free(bitmap_bh->b_data,
1251 EXT4_INODES_PER_GROUP(sb) / 8);
1252 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1253 (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1254 bitmap_count += x;
1255 }
1256 brelse(bitmap_bh);
1257 printk(KERN_DEBUG "ext4_count_free_inodes: "
1258 "stored = %u, computed = %lu, %lu\n",
1259 le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1260 return desc_count;
1261#else
1262 desc_count = 0;
1263 for (i = 0; i < ngroups; i++) {
1264 gdp = ext4_get_group_desc(sb, i, NULL);
1265 if (!gdp)
1266 continue;
1267 desc_count += ext4_free_inodes_count(sb, gdp);
1268 cond_resched();
1269 }
1270 return desc_count;
1271#endif
1272}
1273
1274/* Called at mount-time, super-block is locked */
1275unsigned long ext4_count_dirs(struct super_block * sb)
1276{
1277 unsigned long count = 0;
1278 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1279
1280 for (i = 0; i < ngroups; i++) {
1281 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1282 if (!gdp)
1283 continue;
1284 count += ext4_used_dirs_count(sb, gdp);
1285 }
1286 return count;
1287}
1288
1289/*
1290 * Zeroes not yet zeroed inode table - just write zeroes through the whole
1291 * inode table. Must be called without any spinlock held. The only place
1292 * where it is called from on active part of filesystem is ext4lazyinit
1293 * thread, so we do not need any special locks, however we have to prevent
1294 * inode allocation from the current group, so we take alloc_sem lock, to
1295 * block ext4_new_inode() until we are finished.
1296 */
1297int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1298 int barrier)
1299{
1300 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1301 struct ext4_sb_info *sbi = EXT4_SB(sb);
1302 struct ext4_group_desc *gdp = NULL;
1303 struct buffer_head *group_desc_bh;
1304 handle_t *handle;
1305 ext4_fsblk_t blk;
1306 int num, ret = 0, used_blks = 0;
1307
1308 /* This should not happen, but just to be sure check this */
1309 if (sb->s_flags & MS_RDONLY) {
1310 ret = 1;
1311 goto out;
1312 }
1313
1314 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1315 if (!gdp)
1316 goto out;
1317
1318 /*
1319 * We do not need to lock this, because we are the only one
1320 * handling this flag.
1321 */
1322 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1323 goto out;
1324
1325 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1326 if (IS_ERR(handle)) {
1327 ret = PTR_ERR(handle);
1328 goto out;
1329 }
1330
1331 down_write(&grp->alloc_sem);
1332 /*
1333 * If inode bitmap was already initialized there may be some
1334 * used inodes so we need to skip blocks with used inodes in
1335 * inode table.
1336 */
1337 if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1338 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1339 ext4_itable_unused_count(sb, gdp)),
1340 sbi->s_inodes_per_block);
1341
1342 if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1343 ext4_error(sb, "Something is wrong with group %u: "
1344 "used itable blocks: %d; "
1345 "itable unused count: %u",
1346 group, used_blks,
1347 ext4_itable_unused_count(sb, gdp));
1348 ret = 1;
1349 goto err_out;
1350 }
1351
1352 blk = ext4_inode_table(sb, gdp) + used_blks;
1353 num = sbi->s_itb_per_group - used_blks;
1354
1355 BUFFER_TRACE(group_desc_bh, "get_write_access");
1356 ret = ext4_journal_get_write_access(handle,
1357 group_desc_bh);
1358 if (ret)
1359 goto err_out;
1360
1361 /*
1362 * Skip zeroout if the inode table is full. But we set the ZEROED
1363 * flag anyway, because obviously, when it is full it does not need
1364 * further zeroing.
1365 */
1366 if (unlikely(num == 0))
1367 goto skip_zeroout;
1368
1369 ext4_debug("going to zero out inode table in group %d\n",
1370 group);
1371 ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1372 if (ret < 0)
1373 goto err_out;
1374 if (barrier)
1375 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1376
1377skip_zeroout:
1378 ext4_lock_group(sb, group);
1379 gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1380 ext4_group_desc_csum_set(sb, group, gdp);
1381 ext4_unlock_group(sb, group);
1382
1383 BUFFER_TRACE(group_desc_bh,
1384 "call ext4_handle_dirty_metadata");
1385 ret = ext4_handle_dirty_metadata(handle, NULL,
1386 group_desc_bh);
1387
1388err_out:
1389 up_write(&grp->alloc_sem);
1390 ext4_journal_stop(handle);
1391out:
1392 return ret;
1393}