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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/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_group_info *grp;
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 ext4_error(sb, "Checksum bad for group %u", block_group);
80 grp = ext4_get_group_info(sb, block_group);
81 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
82 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
83 return 0;
84 }
85
86 memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
87 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
88 bh->b_data);
89 ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
90 EXT4_INODES_PER_GROUP(sb) / 8);
91 ext4_group_desc_csum_set(sb, block_group, gdp);
92
93 return EXT4_INODES_PER_GROUP(sb);
94}
95
96void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
97{
98 if (uptodate) {
99 set_buffer_uptodate(bh);
100 set_bitmap_uptodate(bh);
101 }
102 unlock_buffer(bh);
103 put_bh(bh);
104}
105
106/*
107 * Read the inode allocation bitmap for a given block_group, reading
108 * into the specified slot in the superblock's bitmap cache.
109 *
110 * Return buffer_head of bitmap on success or NULL.
111 */
112static struct buffer_head *
113ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
114{
115 struct ext4_group_desc *desc;
116 struct buffer_head *bh = NULL;
117 ext4_fsblk_t bitmap_blk;
118 struct ext4_group_info *grp;
119
120 desc = ext4_get_group_desc(sb, block_group, NULL);
121 if (!desc)
122 return NULL;
123
124 bitmap_blk = ext4_inode_bitmap(sb, desc);
125 bh = sb_getblk(sb, bitmap_blk);
126 if (unlikely(!bh)) {
127 ext4_error(sb, "Cannot read inode bitmap - "
128 "block_group = %u, inode_bitmap = %llu",
129 block_group, bitmap_blk);
130 return NULL;
131 }
132 if (bitmap_uptodate(bh))
133 goto verify;
134
135 lock_buffer(bh);
136 if (bitmap_uptodate(bh)) {
137 unlock_buffer(bh);
138 goto verify;
139 }
140
141 ext4_lock_group(sb, block_group);
142 if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
143 ext4_init_inode_bitmap(sb, bh, block_group, desc);
144 set_bitmap_uptodate(bh);
145 set_buffer_uptodate(bh);
146 set_buffer_verified(bh);
147 ext4_unlock_group(sb, block_group);
148 unlock_buffer(bh);
149 return bh;
150 }
151 ext4_unlock_group(sb, block_group);
152
153 if (buffer_uptodate(bh)) {
154 /*
155 * if not uninit if bh is uptodate,
156 * bitmap is also uptodate
157 */
158 set_bitmap_uptodate(bh);
159 unlock_buffer(bh);
160 goto verify;
161 }
162 /*
163 * submit the buffer_head for reading
164 */
165 trace_ext4_load_inode_bitmap(sb, block_group);
166 bh->b_end_io = ext4_end_bitmap_read;
167 get_bh(bh);
168 submit_bh(READ | REQ_META | REQ_PRIO, bh);
169 wait_on_buffer(bh);
170 if (!buffer_uptodate(bh)) {
171 put_bh(bh);
172 ext4_error(sb, "Cannot read inode bitmap - "
173 "block_group = %u, inode_bitmap = %llu",
174 block_group, bitmap_blk);
175 return NULL;
176 }
177
178verify:
179 ext4_lock_group(sb, block_group);
180 if (!buffer_verified(bh) &&
181 !ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
182 EXT4_INODES_PER_GROUP(sb) / 8)) {
183 ext4_unlock_group(sb, block_group);
184 put_bh(bh);
185 ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
186 "inode_bitmap = %llu", block_group, bitmap_blk);
187 grp = ext4_get_group_info(sb, block_group);
188 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
189 return NULL;
190 }
191 ext4_unlock_group(sb, block_group);
192 set_buffer_verified(bh);
193 return bh;
194}
195
196/*
197 * NOTE! When we get the inode, we're the only people
198 * that have access to it, and as such there are no
199 * race conditions we have to worry about. The inode
200 * is not on the hash-lists, and it cannot be reached
201 * through the filesystem because the directory entry
202 * has been deleted earlier.
203 *
204 * HOWEVER: we must make sure that we get no aliases,
205 * which means that we have to call "clear_inode()"
206 * _before_ we mark the inode not in use in the inode
207 * bitmaps. Otherwise a newly created file might use
208 * the same inode number (not actually the same pointer
209 * though), and then we'd have two inodes sharing the
210 * same inode number and space on the harddisk.
211 */
212void ext4_free_inode(handle_t *handle, struct inode *inode)
213{
214 struct super_block *sb = inode->i_sb;
215 int is_directory;
216 unsigned long ino;
217 struct buffer_head *bitmap_bh = NULL;
218 struct buffer_head *bh2;
219 ext4_group_t block_group;
220 unsigned long bit;
221 struct ext4_group_desc *gdp;
222 struct ext4_super_block *es;
223 struct ext4_sb_info *sbi;
224 int fatal = 0, err, count, cleared;
225 struct ext4_group_info *grp;
226
227 if (!sb) {
228 printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
229 "nonexistent device\n", __func__, __LINE__);
230 return;
231 }
232 if (atomic_read(&inode->i_count) > 1) {
233 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
234 __func__, __LINE__, inode->i_ino,
235 atomic_read(&inode->i_count));
236 return;
237 }
238 if (inode->i_nlink) {
239 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
240 __func__, __LINE__, inode->i_ino, inode->i_nlink);
241 return;
242 }
243 sbi = EXT4_SB(sb);
244
245 ino = inode->i_ino;
246 ext4_debug("freeing inode %lu\n", ino);
247 trace_ext4_free_inode(inode);
248
249 /*
250 * Note: we must free any quota before locking the superblock,
251 * as writing the quota to disk may need the lock as well.
252 */
253 dquot_initialize(inode);
254 ext4_xattr_delete_inode(handle, inode);
255 dquot_free_inode(inode);
256 dquot_drop(inode);
257
258 is_directory = S_ISDIR(inode->i_mode);
259
260 /* Do this BEFORE marking the inode not in use or returning an error */
261 ext4_clear_inode(inode);
262
263 es = EXT4_SB(sb)->s_es;
264 if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
265 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
266 goto error_return;
267 }
268 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
269 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
270 bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
271 /* Don't bother if the inode bitmap is corrupt. */
272 grp = ext4_get_group_info(sb, block_group);
273 if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) || !bitmap_bh)
274 goto error_return;
275
276 BUFFER_TRACE(bitmap_bh, "get_write_access");
277 fatal = ext4_journal_get_write_access(handle, bitmap_bh);
278 if (fatal)
279 goto error_return;
280
281 fatal = -ESRCH;
282 gdp = ext4_get_group_desc(sb, block_group, &bh2);
283 if (gdp) {
284 BUFFER_TRACE(bh2, "get_write_access");
285 fatal = ext4_journal_get_write_access(handle, bh2);
286 }
287 ext4_lock_group(sb, block_group);
288 cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
289 if (fatal || !cleared) {
290 ext4_unlock_group(sb, block_group);
291 goto out;
292 }
293
294 count = ext4_free_inodes_count(sb, gdp) + 1;
295 ext4_free_inodes_set(sb, gdp, count);
296 if (is_directory) {
297 count = ext4_used_dirs_count(sb, gdp) - 1;
298 ext4_used_dirs_set(sb, gdp, count);
299 percpu_counter_dec(&sbi->s_dirs_counter);
300 }
301 ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
302 EXT4_INODES_PER_GROUP(sb) / 8);
303 ext4_group_desc_csum_set(sb, block_group, gdp);
304 ext4_unlock_group(sb, block_group);
305
306 percpu_counter_inc(&sbi->s_freeinodes_counter);
307 if (sbi->s_log_groups_per_flex) {
308 ext4_group_t f = ext4_flex_group(sbi, block_group);
309
310 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
311 if (is_directory)
312 atomic_dec(&sbi->s_flex_groups[f].used_dirs);
313 }
314 BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
315 fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
316out:
317 if (cleared) {
318 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
319 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
320 if (!fatal)
321 fatal = err;
322 } else {
323 ext4_error(sb, "bit already cleared for inode %lu", ino);
324 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
325 }
326
327error_return:
328 brelse(bitmap_bh);
329 ext4_std_error(sb, fatal);
330}
331
332struct orlov_stats {
333 __u64 free_clusters;
334 __u32 free_inodes;
335 __u32 used_dirs;
336};
337
338/*
339 * Helper function for Orlov's allocator; returns critical information
340 * for a particular block group or flex_bg. If flex_size is 1, then g
341 * is a block group number; otherwise it is flex_bg number.
342 */
343static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
344 int flex_size, struct orlov_stats *stats)
345{
346 struct ext4_group_desc *desc;
347 struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
348
349 if (flex_size > 1) {
350 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
351 stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
352 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
353 return;
354 }
355
356 desc = ext4_get_group_desc(sb, g, NULL);
357 if (desc) {
358 stats->free_inodes = ext4_free_inodes_count(sb, desc);
359 stats->free_clusters = ext4_free_group_clusters(sb, desc);
360 stats->used_dirs = ext4_used_dirs_count(sb, desc);
361 } else {
362 stats->free_inodes = 0;
363 stats->free_clusters = 0;
364 stats->used_dirs = 0;
365 }
366}
367
368/*
369 * Orlov's allocator for directories.
370 *
371 * We always try to spread first-level directories.
372 *
373 * If there are blockgroups with both free inodes and free blocks counts
374 * not worse than average we return one with smallest directory count.
375 * Otherwise we simply return a random group.
376 *
377 * For the rest rules look so:
378 *
379 * It's OK to put directory into a group unless
380 * it has too many directories already (max_dirs) or
381 * it has too few free inodes left (min_inodes) or
382 * it has too few free blocks left (min_blocks) or
383 * Parent's group is preferred, if it doesn't satisfy these
384 * conditions we search cyclically through the rest. If none
385 * of the groups look good we just look for a group with more
386 * free inodes than average (starting at parent's group).
387 */
388
389static int find_group_orlov(struct super_block *sb, struct inode *parent,
390 ext4_group_t *group, umode_t mode,
391 const struct qstr *qstr)
392{
393 ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
394 struct ext4_sb_info *sbi = EXT4_SB(sb);
395 ext4_group_t real_ngroups = ext4_get_groups_count(sb);
396 int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
397 unsigned int freei, avefreei, grp_free;
398 ext4_fsblk_t freeb, avefreec;
399 unsigned int ndirs;
400 int max_dirs, min_inodes;
401 ext4_grpblk_t min_clusters;
402 ext4_group_t i, grp, g, ngroups;
403 struct ext4_group_desc *desc;
404 struct orlov_stats stats;
405 int flex_size = ext4_flex_bg_size(sbi);
406 struct dx_hash_info hinfo;
407
408 ngroups = real_ngroups;
409 if (flex_size > 1) {
410 ngroups = (real_ngroups + flex_size - 1) >>
411 sbi->s_log_groups_per_flex;
412 parent_group >>= sbi->s_log_groups_per_flex;
413 }
414
415 freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
416 avefreei = freei / ngroups;
417 freeb = EXT4_C2B(sbi,
418 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
419 avefreec = freeb;
420 do_div(avefreec, ngroups);
421 ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
422
423 if (S_ISDIR(mode) &&
424 ((parent == sb->s_root->d_inode) ||
425 (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
426 int best_ndir = inodes_per_group;
427 int ret = -1;
428
429 if (qstr) {
430 hinfo.hash_version = DX_HASH_HALF_MD4;
431 hinfo.seed = sbi->s_hash_seed;
432 ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
433 grp = hinfo.hash;
434 } else
435 grp = prandom_u32();
436 parent_group = (unsigned)grp % ngroups;
437 for (i = 0; i < ngroups; i++) {
438 g = (parent_group + i) % ngroups;
439 get_orlov_stats(sb, g, flex_size, &stats);
440 if (!stats.free_inodes)
441 continue;
442 if (stats.used_dirs >= best_ndir)
443 continue;
444 if (stats.free_inodes < avefreei)
445 continue;
446 if (stats.free_clusters < avefreec)
447 continue;
448 grp = g;
449 ret = 0;
450 best_ndir = stats.used_dirs;
451 }
452 if (ret)
453 goto fallback;
454 found_flex_bg:
455 if (flex_size == 1) {
456 *group = grp;
457 return 0;
458 }
459
460 /*
461 * We pack inodes at the beginning of the flexgroup's
462 * inode tables. Block allocation decisions will do
463 * something similar, although regular files will
464 * start at 2nd block group of the flexgroup. See
465 * ext4_ext_find_goal() and ext4_find_near().
466 */
467 grp *= flex_size;
468 for (i = 0; i < flex_size; i++) {
469 if (grp+i >= real_ngroups)
470 break;
471 desc = ext4_get_group_desc(sb, grp+i, NULL);
472 if (desc && ext4_free_inodes_count(sb, desc)) {
473 *group = grp+i;
474 return 0;
475 }
476 }
477 goto fallback;
478 }
479
480 max_dirs = ndirs / ngroups + inodes_per_group / 16;
481 min_inodes = avefreei - inodes_per_group*flex_size / 4;
482 if (min_inodes < 1)
483 min_inodes = 1;
484 min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
485
486 /*
487 * Start looking in the flex group where we last allocated an
488 * inode for this parent directory
489 */
490 if (EXT4_I(parent)->i_last_alloc_group != ~0) {
491 parent_group = EXT4_I(parent)->i_last_alloc_group;
492 if (flex_size > 1)
493 parent_group >>= sbi->s_log_groups_per_flex;
494 }
495
496 for (i = 0; i < ngroups; i++) {
497 grp = (parent_group + i) % ngroups;
498 get_orlov_stats(sb, grp, flex_size, &stats);
499 if (stats.used_dirs >= max_dirs)
500 continue;
501 if (stats.free_inodes < min_inodes)
502 continue;
503 if (stats.free_clusters < min_clusters)
504 continue;
505 goto found_flex_bg;
506 }
507
508fallback:
509 ngroups = real_ngroups;
510 avefreei = freei / ngroups;
511fallback_retry:
512 parent_group = EXT4_I(parent)->i_block_group;
513 for (i = 0; i < ngroups; i++) {
514 grp = (parent_group + i) % ngroups;
515 desc = ext4_get_group_desc(sb, grp, NULL);
516 if (desc) {
517 grp_free = ext4_free_inodes_count(sb, desc);
518 if (grp_free && grp_free >= avefreei) {
519 *group = grp;
520 return 0;
521 }
522 }
523 }
524
525 if (avefreei) {
526 /*
527 * The free-inodes counter is approximate, and for really small
528 * filesystems the above test can fail to find any blockgroups
529 */
530 avefreei = 0;
531 goto fallback_retry;
532 }
533
534 return -1;
535}
536
537static int find_group_other(struct super_block *sb, struct inode *parent,
538 ext4_group_t *group, umode_t mode)
539{
540 ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
541 ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
542 struct ext4_group_desc *desc;
543 int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
544
545 /*
546 * Try to place the inode is the same flex group as its
547 * parent. If we can't find space, use the Orlov algorithm to
548 * find another flex group, and store that information in the
549 * parent directory's inode information so that use that flex
550 * group for future allocations.
551 */
552 if (flex_size > 1) {
553 int retry = 0;
554
555 try_again:
556 parent_group &= ~(flex_size-1);
557 last = parent_group + flex_size;
558 if (last > ngroups)
559 last = ngroups;
560 for (i = parent_group; i < last; i++) {
561 desc = ext4_get_group_desc(sb, i, NULL);
562 if (desc && ext4_free_inodes_count(sb, desc)) {
563 *group = i;
564 return 0;
565 }
566 }
567 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
568 retry = 1;
569 parent_group = EXT4_I(parent)->i_last_alloc_group;
570 goto try_again;
571 }
572 /*
573 * If this didn't work, use the Orlov search algorithm
574 * to find a new flex group; we pass in the mode to
575 * avoid the topdir algorithms.
576 */
577 *group = parent_group + flex_size;
578 if (*group > ngroups)
579 *group = 0;
580 return find_group_orlov(sb, parent, group, mode, NULL);
581 }
582
583 /*
584 * Try to place the inode in its parent directory
585 */
586 *group = parent_group;
587 desc = ext4_get_group_desc(sb, *group, NULL);
588 if (desc && ext4_free_inodes_count(sb, desc) &&
589 ext4_free_group_clusters(sb, desc))
590 return 0;
591
592 /*
593 * We're going to place this inode in a different blockgroup from its
594 * parent. We want to cause files in a common directory to all land in
595 * the same blockgroup. But we want files which are in a different
596 * directory which shares a blockgroup with our parent to land in a
597 * different blockgroup.
598 *
599 * So add our directory's i_ino into the starting point for the hash.
600 */
601 *group = (*group + parent->i_ino) % ngroups;
602
603 /*
604 * Use a quadratic hash to find a group with a free inode and some free
605 * blocks.
606 */
607 for (i = 1; i < ngroups; i <<= 1) {
608 *group += i;
609 if (*group >= ngroups)
610 *group -= ngroups;
611 desc = ext4_get_group_desc(sb, *group, NULL);
612 if (desc && ext4_free_inodes_count(sb, desc) &&
613 ext4_free_group_clusters(sb, desc))
614 return 0;
615 }
616
617 /*
618 * That failed: try linear search for a free inode, even if that group
619 * has no free blocks.
620 */
621 *group = parent_group;
622 for (i = 0; i < ngroups; i++) {
623 if (++*group >= ngroups)
624 *group = 0;
625 desc = ext4_get_group_desc(sb, *group, NULL);
626 if (desc && ext4_free_inodes_count(sb, desc))
627 return 0;
628 }
629
630 return -1;
631}
632
633/*
634 * In no journal mode, if an inode has recently been deleted, we want
635 * to avoid reusing it until we're reasonably sure the inode table
636 * block has been written back to disk. (Yes, these values are
637 * somewhat arbitrary...)
638 */
639#define RECENTCY_MIN 5
640#define RECENTCY_DIRTY 30
641
642static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
643{
644 struct ext4_group_desc *gdp;
645 struct ext4_inode *raw_inode;
646 struct buffer_head *bh;
647 unsigned long dtime, now;
648 int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
649 int offset, ret = 0, recentcy = RECENTCY_MIN;
650
651 gdp = ext4_get_group_desc(sb, group, NULL);
652 if (unlikely(!gdp))
653 return 0;
654
655 bh = sb_getblk(sb, ext4_inode_table(sb, gdp) +
656 (ino / inodes_per_block));
657 if (unlikely(!bh) || !buffer_uptodate(bh))
658 /*
659 * If the block is not in the buffer cache, then it
660 * must have been written out.
661 */
662 goto out;
663
664 offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
665 raw_inode = (struct ext4_inode *) (bh->b_data + offset);
666 dtime = le32_to_cpu(raw_inode->i_dtime);
667 now = get_seconds();
668 if (buffer_dirty(bh))
669 recentcy += RECENTCY_DIRTY;
670
671 if (dtime && (dtime < now) && (now < dtime + recentcy))
672 ret = 1;
673out:
674 brelse(bh);
675 return ret;
676}
677
678/*
679 * There are two policies for allocating an inode. If the new inode is
680 * a directory, then a forward search is made for a block group with both
681 * free space and a low directory-to-inode ratio; if that fails, then of
682 * the groups with above-average free space, that group with the fewest
683 * directories already is chosen.
684 *
685 * For other inodes, search forward from the parent directory's block
686 * group to find a free inode.
687 */
688struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
689 umode_t mode, const struct qstr *qstr,
690 __u32 goal, uid_t *owner, int handle_type,
691 unsigned int line_no, int nblocks)
692{
693 struct super_block *sb;
694 struct buffer_head *inode_bitmap_bh = NULL;
695 struct buffer_head *group_desc_bh;
696 ext4_group_t ngroups, group = 0;
697 unsigned long ino = 0;
698 struct inode *inode;
699 struct ext4_group_desc *gdp = NULL;
700 struct ext4_inode_info *ei;
701 struct ext4_sb_info *sbi;
702 int ret2, err = 0;
703 struct inode *ret;
704 ext4_group_t i;
705 ext4_group_t flex_group;
706 struct ext4_group_info *grp;
707
708 /* Cannot create files in a deleted directory */
709 if (!dir || !dir->i_nlink)
710 return ERR_PTR(-EPERM);
711
712 sb = dir->i_sb;
713 ngroups = ext4_get_groups_count(sb);
714 trace_ext4_request_inode(dir, mode);
715 inode = new_inode(sb);
716 if (!inode)
717 return ERR_PTR(-ENOMEM);
718 ei = EXT4_I(inode);
719 sbi = EXT4_SB(sb);
720
721 /*
722 * Initalize owners and quota early so that we don't have to account
723 * for quota initialization worst case in standard inode creating
724 * transaction
725 */
726 if (owner) {
727 inode->i_mode = mode;
728 i_uid_write(inode, owner[0]);
729 i_gid_write(inode, owner[1]);
730 } else if (test_opt(sb, GRPID)) {
731 inode->i_mode = mode;
732 inode->i_uid = current_fsuid();
733 inode->i_gid = dir->i_gid;
734 } else
735 inode_init_owner(inode, dir, mode);
736 dquot_initialize(inode);
737
738 if (!goal)
739 goal = sbi->s_inode_goal;
740
741 if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
742 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
743 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
744 ret2 = 0;
745 goto got_group;
746 }
747
748 if (S_ISDIR(mode))
749 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
750 else
751 ret2 = find_group_other(sb, dir, &group, mode);
752
753got_group:
754 EXT4_I(dir)->i_last_alloc_group = group;
755 err = -ENOSPC;
756 if (ret2 == -1)
757 goto out;
758
759 /*
760 * Normally we will only go through one pass of this loop,
761 * unless we get unlucky and it turns out the group we selected
762 * had its last inode grabbed by someone else.
763 */
764 for (i = 0; i < ngroups; i++, ino = 0) {
765 err = -EIO;
766
767 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
768 if (!gdp)
769 goto out;
770
771 /*
772 * Check free inodes count before loading bitmap.
773 */
774 if (ext4_free_inodes_count(sb, gdp) == 0) {
775 if (++group == ngroups)
776 group = 0;
777 continue;
778 }
779
780 grp = ext4_get_group_info(sb, group);
781 /* Skip groups with already-known suspicious inode tables */
782 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
783 if (++group == ngroups)
784 group = 0;
785 continue;
786 }
787
788 brelse(inode_bitmap_bh);
789 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
790 /* Skip groups with suspicious inode tables */
791 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) || !inode_bitmap_bh) {
792 if (++group == ngroups)
793 group = 0;
794 continue;
795 }
796
797repeat_in_this_group:
798 ino = ext4_find_next_zero_bit((unsigned long *)
799 inode_bitmap_bh->b_data,
800 EXT4_INODES_PER_GROUP(sb), ino);
801 if (ino >= EXT4_INODES_PER_GROUP(sb))
802 goto next_group;
803 if (group == 0 && (ino+1) < EXT4_FIRST_INO(sb)) {
804 ext4_error(sb, "reserved inode found cleared - "
805 "inode=%lu", ino + 1);
806 continue;
807 }
808 if ((EXT4_SB(sb)->s_journal == NULL) &&
809 recently_deleted(sb, group, ino)) {
810 ino++;
811 goto next_inode;
812 }
813 if (!handle) {
814 BUG_ON(nblocks <= 0);
815 handle = __ext4_journal_start_sb(dir->i_sb, line_no,
816 handle_type, nblocks,
817 0);
818 if (IS_ERR(handle)) {
819 err = PTR_ERR(handle);
820 ext4_std_error(sb, err);
821 goto out;
822 }
823 }
824 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
825 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
826 if (err) {
827 ext4_std_error(sb, err);
828 goto out;
829 }
830 ext4_lock_group(sb, group);
831 ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
832 ext4_unlock_group(sb, group);
833 ino++; /* the inode bitmap is zero-based */
834 if (!ret2)
835 goto got; /* we grabbed the inode! */
836next_inode:
837 if (ino < EXT4_INODES_PER_GROUP(sb))
838 goto repeat_in_this_group;
839next_group:
840 if (++group == ngroups)
841 group = 0;
842 }
843 err = -ENOSPC;
844 goto out;
845
846got:
847 BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
848 err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
849 if (err) {
850 ext4_std_error(sb, err);
851 goto out;
852 }
853
854 /* We may have to initialize the block bitmap if it isn't already */
855 if (ext4_has_group_desc_csum(sb) &&
856 gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
857 struct buffer_head *block_bitmap_bh;
858
859 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
860 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
861 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
862 if (err) {
863 brelse(block_bitmap_bh);
864 ext4_std_error(sb, err);
865 goto out;
866 }
867
868 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
869 err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
870
871 /* recheck and clear flag under lock if we still need to */
872 ext4_lock_group(sb, group);
873 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
874 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
875 ext4_free_group_clusters_set(sb, gdp,
876 ext4_free_clusters_after_init(sb, group, gdp));
877 ext4_block_bitmap_csum_set(sb, group, gdp,
878 block_bitmap_bh);
879 ext4_group_desc_csum_set(sb, group, gdp);
880 }
881 ext4_unlock_group(sb, group);
882 brelse(block_bitmap_bh);
883
884 if (err) {
885 ext4_std_error(sb, err);
886 goto out;
887 }
888 }
889
890 BUFFER_TRACE(group_desc_bh, "get_write_access");
891 err = ext4_journal_get_write_access(handle, group_desc_bh);
892 if (err) {
893 ext4_std_error(sb, err);
894 goto out;
895 }
896
897 /* Update the relevant bg descriptor fields */
898 if (ext4_has_group_desc_csum(sb)) {
899 int free;
900 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
901
902 down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
903 ext4_lock_group(sb, group); /* while we modify the bg desc */
904 free = EXT4_INODES_PER_GROUP(sb) -
905 ext4_itable_unused_count(sb, gdp);
906 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
907 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
908 free = 0;
909 }
910 /*
911 * Check the relative inode number against the last used
912 * relative inode number in this group. if it is greater
913 * we need to update the bg_itable_unused count
914 */
915 if (ino > free)
916 ext4_itable_unused_set(sb, gdp,
917 (EXT4_INODES_PER_GROUP(sb) - ino));
918 up_read(&grp->alloc_sem);
919 } else {
920 ext4_lock_group(sb, group);
921 }
922
923 ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
924 if (S_ISDIR(mode)) {
925 ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
926 if (sbi->s_log_groups_per_flex) {
927 ext4_group_t f = ext4_flex_group(sbi, group);
928
929 atomic_inc(&sbi->s_flex_groups[f].used_dirs);
930 }
931 }
932 if (ext4_has_group_desc_csum(sb)) {
933 ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
934 EXT4_INODES_PER_GROUP(sb) / 8);
935 ext4_group_desc_csum_set(sb, group, gdp);
936 }
937 ext4_unlock_group(sb, group);
938
939 BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
940 err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
941 if (err) {
942 ext4_std_error(sb, err);
943 goto out;
944 }
945
946 percpu_counter_dec(&sbi->s_freeinodes_counter);
947 if (S_ISDIR(mode))
948 percpu_counter_inc(&sbi->s_dirs_counter);
949
950 if (sbi->s_log_groups_per_flex) {
951 flex_group = ext4_flex_group(sbi, group);
952 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
953 }
954
955 inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
956 /* This is the optimal IO size (for stat), not the fs block size */
957 inode->i_blocks = 0;
958 inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
959 ext4_current_time(inode);
960
961 memset(ei->i_data, 0, sizeof(ei->i_data));
962 ei->i_dir_start_lookup = 0;
963 ei->i_disksize = 0;
964
965 /* Don't inherit extent flag from directory, amongst others. */
966 ei->i_flags =
967 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
968 ei->i_file_acl = 0;
969 ei->i_dtime = 0;
970 ei->i_block_group = group;
971 ei->i_last_alloc_group = ~0;
972
973 ext4_set_inode_flags(inode);
974 if (IS_DIRSYNC(inode))
975 ext4_handle_sync(handle);
976 if (insert_inode_locked(inode) < 0) {
977 /*
978 * Likely a bitmap corruption causing inode to be allocated
979 * twice.
980 */
981 err = -EIO;
982 ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
983 inode->i_ino);
984 goto out;
985 }
986 spin_lock(&sbi->s_next_gen_lock);
987 inode->i_generation = sbi->s_next_generation++;
988 spin_unlock(&sbi->s_next_gen_lock);
989
990 /* Precompute checksum seed for inode metadata */
991 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
992 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
993 __u32 csum;
994 __le32 inum = cpu_to_le32(inode->i_ino);
995 __le32 gen = cpu_to_le32(inode->i_generation);
996 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
997 sizeof(inum));
998 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
999 sizeof(gen));
1000 }
1001
1002 ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1003 ext4_set_inode_state(inode, EXT4_STATE_NEW);
1004
1005 ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
1006
1007 ei->i_inline_off = 0;
1008 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_INLINE_DATA))
1009 ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1010
1011 ret = inode;
1012 err = dquot_alloc_inode(inode);
1013 if (err)
1014 goto fail_drop;
1015
1016 err = ext4_init_acl(handle, inode, dir);
1017 if (err)
1018 goto fail_free_drop;
1019
1020 err = ext4_init_security(handle, inode, dir, qstr);
1021 if (err)
1022 goto fail_free_drop;
1023
1024 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
1025 /* set extent flag only for directory, file and normal symlink*/
1026 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1027 ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1028 ext4_ext_tree_init(handle, inode);
1029 }
1030 }
1031
1032 if (ext4_handle_valid(handle)) {
1033 ei->i_sync_tid = handle->h_transaction->t_tid;
1034 ei->i_datasync_tid = handle->h_transaction->t_tid;
1035 }
1036
1037 err = ext4_mark_inode_dirty(handle, inode);
1038 if (err) {
1039 ext4_std_error(sb, err);
1040 goto fail_free_drop;
1041 }
1042
1043 ext4_debug("allocating inode %lu\n", inode->i_ino);
1044 trace_ext4_allocate_inode(inode, dir, mode);
1045 brelse(inode_bitmap_bh);
1046 return ret;
1047
1048fail_free_drop:
1049 dquot_free_inode(inode);
1050fail_drop:
1051 clear_nlink(inode);
1052 unlock_new_inode(inode);
1053out:
1054 dquot_drop(inode);
1055 inode->i_flags |= S_NOQUOTA;
1056 iput(inode);
1057 brelse(inode_bitmap_bh);
1058 return ERR_PTR(err);
1059}
1060
1061/* Verify that we are loading a valid orphan from disk */
1062struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1063{
1064 unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1065 ext4_group_t block_group;
1066 int bit;
1067 struct buffer_head *bitmap_bh;
1068 struct inode *inode = NULL;
1069 long err = -EIO;
1070
1071 /* Error cases - e2fsck has already cleaned up for us */
1072 if (ino > max_ino) {
1073 ext4_warning(sb, "bad orphan ino %lu! e2fsck was run?", ino);
1074 goto error;
1075 }
1076
1077 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1078 bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1079 bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1080 if (!bitmap_bh) {
1081 ext4_warning(sb, "inode bitmap error for orphan %lu", ino);
1082 goto error;
1083 }
1084
1085 /* Having the inode bit set should be a 100% indicator that this
1086 * is a valid orphan (no e2fsck run on fs). Orphans also include
1087 * inodes that were being truncated, so we can't check i_nlink==0.
1088 */
1089 if (!ext4_test_bit(bit, bitmap_bh->b_data))
1090 goto bad_orphan;
1091
1092 inode = ext4_iget(sb, ino);
1093 if (IS_ERR(inode))
1094 goto iget_failed;
1095
1096 /*
1097 * If the orphans has i_nlinks > 0 then it should be able to be
1098 * truncated, otherwise it won't be removed from the orphan list
1099 * during processing and an infinite loop will result.
1100 */
1101 if (inode->i_nlink && !ext4_can_truncate(inode))
1102 goto bad_orphan;
1103
1104 if (NEXT_ORPHAN(inode) > max_ino)
1105 goto bad_orphan;
1106 brelse(bitmap_bh);
1107 return inode;
1108
1109iget_failed:
1110 err = PTR_ERR(inode);
1111 inode = NULL;
1112bad_orphan:
1113 ext4_warning(sb, "bad orphan inode %lu! e2fsck was run?", ino);
1114 printk(KERN_WARNING "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1115 bit, (unsigned long long)bitmap_bh->b_blocknr,
1116 ext4_test_bit(bit, bitmap_bh->b_data));
1117 printk(KERN_WARNING "inode=%p\n", inode);
1118 if (inode) {
1119 printk(KERN_WARNING "is_bad_inode(inode)=%d\n",
1120 is_bad_inode(inode));
1121 printk(KERN_WARNING "NEXT_ORPHAN(inode)=%u\n",
1122 NEXT_ORPHAN(inode));
1123 printk(KERN_WARNING "max_ino=%lu\n", max_ino);
1124 printk(KERN_WARNING "i_nlink=%u\n", inode->i_nlink);
1125 /* Avoid freeing blocks if we got a bad deleted inode */
1126 if (inode->i_nlink == 0)
1127 inode->i_blocks = 0;
1128 iput(inode);
1129 }
1130 brelse(bitmap_bh);
1131error:
1132 return ERR_PTR(err);
1133}
1134
1135unsigned long ext4_count_free_inodes(struct super_block *sb)
1136{
1137 unsigned long desc_count;
1138 struct ext4_group_desc *gdp;
1139 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1140#ifdef EXT4FS_DEBUG
1141 struct ext4_super_block *es;
1142 unsigned long bitmap_count, x;
1143 struct buffer_head *bitmap_bh = NULL;
1144
1145 es = EXT4_SB(sb)->s_es;
1146 desc_count = 0;
1147 bitmap_count = 0;
1148 gdp = NULL;
1149 for (i = 0; i < ngroups; i++) {
1150 gdp = ext4_get_group_desc(sb, i, NULL);
1151 if (!gdp)
1152 continue;
1153 desc_count += ext4_free_inodes_count(sb, gdp);
1154 brelse(bitmap_bh);
1155 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1156 if (!bitmap_bh)
1157 continue;
1158
1159 x = ext4_count_free(bitmap_bh->b_data,
1160 EXT4_INODES_PER_GROUP(sb) / 8);
1161 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1162 (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1163 bitmap_count += x;
1164 }
1165 brelse(bitmap_bh);
1166 printk(KERN_DEBUG "ext4_count_free_inodes: "
1167 "stored = %u, computed = %lu, %lu\n",
1168 le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1169 return desc_count;
1170#else
1171 desc_count = 0;
1172 for (i = 0; i < ngroups; i++) {
1173 gdp = ext4_get_group_desc(sb, i, NULL);
1174 if (!gdp)
1175 continue;
1176 desc_count += ext4_free_inodes_count(sb, gdp);
1177 cond_resched();
1178 }
1179 return desc_count;
1180#endif
1181}
1182
1183/* Called at mount-time, super-block is locked */
1184unsigned long ext4_count_dirs(struct super_block * sb)
1185{
1186 unsigned long count = 0;
1187 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1188
1189 for (i = 0; i < ngroups; i++) {
1190 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1191 if (!gdp)
1192 continue;
1193 count += ext4_used_dirs_count(sb, gdp);
1194 }
1195 return count;
1196}
1197
1198/*
1199 * Zeroes not yet zeroed inode table - just write zeroes through the whole
1200 * inode table. Must be called without any spinlock held. The only place
1201 * where it is called from on active part of filesystem is ext4lazyinit
1202 * thread, so we do not need any special locks, however we have to prevent
1203 * inode allocation from the current group, so we take alloc_sem lock, to
1204 * block ext4_new_inode() until we are finished.
1205 */
1206int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1207 int barrier)
1208{
1209 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1210 struct ext4_sb_info *sbi = EXT4_SB(sb);
1211 struct ext4_group_desc *gdp = NULL;
1212 struct buffer_head *group_desc_bh;
1213 handle_t *handle;
1214 ext4_fsblk_t blk;
1215 int num, ret = 0, used_blks = 0;
1216
1217 /* This should not happen, but just to be sure check this */
1218 if (sb->s_flags & MS_RDONLY) {
1219 ret = 1;
1220 goto out;
1221 }
1222
1223 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1224 if (!gdp)
1225 goto out;
1226
1227 /*
1228 * We do not need to lock this, because we are the only one
1229 * handling this flag.
1230 */
1231 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1232 goto out;
1233
1234 handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1235 if (IS_ERR(handle)) {
1236 ret = PTR_ERR(handle);
1237 goto out;
1238 }
1239
1240 down_write(&grp->alloc_sem);
1241 /*
1242 * If inode bitmap was already initialized there may be some
1243 * used inodes so we need to skip blocks with used inodes in
1244 * inode table.
1245 */
1246 if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1247 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1248 ext4_itable_unused_count(sb, gdp)),
1249 sbi->s_inodes_per_block);
1250
1251 if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1252 ext4_error(sb, "Something is wrong with group %u: "
1253 "used itable blocks: %d; "
1254 "itable unused count: %u",
1255 group, used_blks,
1256 ext4_itable_unused_count(sb, gdp));
1257 ret = 1;
1258 goto err_out;
1259 }
1260
1261 blk = ext4_inode_table(sb, gdp) + used_blks;
1262 num = sbi->s_itb_per_group - used_blks;
1263
1264 BUFFER_TRACE(group_desc_bh, "get_write_access");
1265 ret = ext4_journal_get_write_access(handle,
1266 group_desc_bh);
1267 if (ret)
1268 goto err_out;
1269
1270 /*
1271 * Skip zeroout if the inode table is full. But we set the ZEROED
1272 * flag anyway, because obviously, when it is full it does not need
1273 * further zeroing.
1274 */
1275 if (unlikely(num == 0))
1276 goto skip_zeroout;
1277
1278 ext4_debug("going to zero out inode table in group %d\n",
1279 group);
1280 ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1281 if (ret < 0)
1282 goto err_out;
1283 if (barrier)
1284 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1285
1286skip_zeroout:
1287 ext4_lock_group(sb, group);
1288 gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1289 ext4_group_desc_csum_set(sb, group, gdp);
1290 ext4_unlock_group(sb, group);
1291
1292 BUFFER_TRACE(group_desc_bh,
1293 "call ext4_handle_dirty_metadata");
1294 ret = ext4_handle_dirty_metadata(handle, NULL,
1295 group_desc_bh);
1296
1297err_out:
1298 up_write(&grp->alloc_sem);
1299 ext4_journal_stop(handle);
1300out:
1301 return ret;
1302}