xref: /linux/fs/ext4/ialloc.c (revision af50e4ba34f4c45e92535364133d4deb5931c1c5)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/ext4/ialloc.c
4  *
5  * Copyright (C) 1992, 1993, 1994, 1995
6  * Remy Card (card@masi.ibp.fr)
7  * Laboratoire MASI - Institut Blaise Pascal
8  * Universite Pierre et Marie Curie (Paris VI)
9  *
10  *  BSD ufs-inspired inode and directory allocation by
11  *  Stephen Tweedie (sct@redhat.com), 1993
12  *  Big-endian to little-endian byte-swapping/bitmaps by
13  *        David S. Miller (davem@caip.rutgers.edu), 1995
14  */
15 
16 #include <linux/time.h>
17 #include <linux/fs.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 <linux/cred.h>
26 
27 #include <asm/byteorder.h>
28 
29 #include "ext4.h"
30 #include "ext4_jbd2.h"
31 #include "xattr.h"
32 #include "acl.h"
33 
34 #include <trace/events/ext4.h>
35 
36 /*
37  * ialloc.c contains the inodes allocation and deallocation routines
38  */
39 
40 /*
41  * The free inodes are managed by bitmaps.  A file system contains several
42  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
43  * block for inodes, N blocks for the inode table and data blocks.
44  *
45  * The file system contains group descriptors which are located after the
46  * super block.  Each descriptor contains the number of the bitmap block and
47  * the free blocks count in the block.
48  */
49 
50 /*
51  * To avoid calling the atomic setbit hundreds or thousands of times, we only
52  * need to use it within a single byte (to ensure we get endianness right).
53  * We can use memset for the rest of the bitmap as there are no other users.
54  */
55 void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
56 {
57 	int i;
58 
59 	if (start_bit >= end_bit)
60 		return;
61 
62 	ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
63 	for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
64 		ext4_set_bit(i, bitmap);
65 	if (i < end_bit)
66 		memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
67 }
68 
69 void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
70 {
71 	if (uptodate) {
72 		set_buffer_uptodate(bh);
73 		set_bitmap_uptodate(bh);
74 	}
75 	unlock_buffer(bh);
76 	put_bh(bh);
77 }
78 
79 static int ext4_validate_inode_bitmap(struct super_block *sb,
80 				      struct ext4_group_desc *desc,
81 				      ext4_group_t block_group,
82 				      struct buffer_head *bh)
83 {
84 	ext4_fsblk_t	blk;
85 	struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
86 	struct ext4_sb_info *sbi = EXT4_SB(sb);
87 
88 	if (buffer_verified(bh))
89 		return 0;
90 	if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
91 		return -EFSCORRUPTED;
92 
93 	ext4_lock_group(sb, block_group);
94 	blk = ext4_inode_bitmap(sb, desc);
95 	if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
96 					   EXT4_INODES_PER_GROUP(sb) / 8)) {
97 		ext4_unlock_group(sb, block_group);
98 		ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
99 			   "inode_bitmap = %llu", block_group, blk);
100 		grp = ext4_get_group_info(sb, block_group);
101 		if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
102 			int count;
103 			count = ext4_free_inodes_count(sb, desc);
104 			percpu_counter_sub(&sbi->s_freeinodes_counter,
105 					   count);
106 		}
107 		set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
108 		return -EFSBADCRC;
109 	}
110 	set_buffer_verified(bh);
111 	ext4_unlock_group(sb, block_group);
112 	return 0;
113 }
114 
115 /*
116  * Read the inode allocation bitmap for a given block_group, reading
117  * into the specified slot in the superblock's bitmap cache.
118  *
119  * Return buffer_head of bitmap on success or NULL.
120  */
121 static struct buffer_head *
122 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
123 {
124 	struct ext4_group_desc *desc;
125 	struct ext4_sb_info *sbi = EXT4_SB(sb);
126 	struct buffer_head *bh = NULL;
127 	ext4_fsblk_t bitmap_blk;
128 	int err;
129 
130 	desc = ext4_get_group_desc(sb, block_group, NULL);
131 	if (!desc)
132 		return ERR_PTR(-EFSCORRUPTED);
133 
134 	bitmap_blk = ext4_inode_bitmap(sb, desc);
135 	if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
136 	    (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
137 		ext4_error(sb, "Invalid inode bitmap blk %llu in "
138 			   "block_group %u", bitmap_blk, block_group);
139 		return ERR_PTR(-EFSCORRUPTED);
140 	}
141 	bh = sb_getblk(sb, bitmap_blk);
142 	if (unlikely(!bh)) {
143 		ext4_error(sb, "Cannot read inode bitmap - "
144 			    "block_group = %u, inode_bitmap = %llu",
145 			    block_group, bitmap_blk);
146 		return ERR_PTR(-EIO);
147 	}
148 	if (bitmap_uptodate(bh))
149 		goto verify;
150 
151 	lock_buffer(bh);
152 	if (bitmap_uptodate(bh)) {
153 		unlock_buffer(bh);
154 		goto verify;
155 	}
156 
157 	ext4_lock_group(sb, block_group);
158 	if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
159 		memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
160 		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
161 				     sb->s_blocksize * 8, bh->b_data);
162 		set_bitmap_uptodate(bh);
163 		set_buffer_uptodate(bh);
164 		set_buffer_verified(bh);
165 		ext4_unlock_group(sb, block_group);
166 		unlock_buffer(bh);
167 		return bh;
168 	}
169 	ext4_unlock_group(sb, block_group);
170 
171 	if (buffer_uptodate(bh)) {
172 		/*
173 		 * if not uninit if bh is uptodate,
174 		 * bitmap is also uptodate
175 		 */
176 		set_bitmap_uptodate(bh);
177 		unlock_buffer(bh);
178 		goto verify;
179 	}
180 	/*
181 	 * submit the buffer_head for reading
182 	 */
183 	trace_ext4_load_inode_bitmap(sb, block_group);
184 	bh->b_end_io = ext4_end_bitmap_read;
185 	get_bh(bh);
186 	submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
187 	wait_on_buffer(bh);
188 	if (!buffer_uptodate(bh)) {
189 		put_bh(bh);
190 		ext4_error(sb, "Cannot read inode bitmap - "
191 			   "block_group = %u, inode_bitmap = %llu",
192 			   block_group, bitmap_blk);
193 		return ERR_PTR(-EIO);
194 	}
195 
196 verify:
197 	err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
198 	if (err)
199 		goto out;
200 	return bh;
201 out:
202 	put_bh(bh);
203 	return ERR_PTR(err);
204 }
205 
206 /*
207  * NOTE! When we get the inode, we're the only people
208  * that have access to it, and as such there are no
209  * race conditions we have to worry about. The inode
210  * is not on the hash-lists, and it cannot be reached
211  * through the filesystem because the directory entry
212  * has been deleted earlier.
213  *
214  * HOWEVER: we must make sure that we get no aliases,
215  * which means that we have to call "clear_inode()"
216  * _before_ we mark the inode not in use in the inode
217  * bitmaps. Otherwise a newly created file might use
218  * the same inode number (not actually the same pointer
219  * though), and then we'd have two inodes sharing the
220  * same inode number and space on the harddisk.
221  */
222 void ext4_free_inode(handle_t *handle, struct inode *inode)
223 {
224 	struct super_block *sb = inode->i_sb;
225 	int is_directory;
226 	unsigned long ino;
227 	struct buffer_head *bitmap_bh = NULL;
228 	struct buffer_head *bh2;
229 	ext4_group_t block_group;
230 	unsigned long bit;
231 	struct ext4_group_desc *gdp;
232 	struct ext4_super_block *es;
233 	struct ext4_sb_info *sbi;
234 	int fatal = 0, err, count, cleared;
235 	struct ext4_group_info *grp;
236 
237 	if (!sb) {
238 		printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
239 		       "nonexistent device\n", __func__, __LINE__);
240 		return;
241 	}
242 	if (atomic_read(&inode->i_count) > 1) {
243 		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
244 			 __func__, __LINE__, inode->i_ino,
245 			 atomic_read(&inode->i_count));
246 		return;
247 	}
248 	if (inode->i_nlink) {
249 		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
250 			 __func__, __LINE__, inode->i_ino, inode->i_nlink);
251 		return;
252 	}
253 	sbi = EXT4_SB(sb);
254 
255 	ino = inode->i_ino;
256 	ext4_debug("freeing inode %lu\n", ino);
257 	trace_ext4_free_inode(inode);
258 
259 	/*
260 	 * Note: we must free any quota before locking the superblock,
261 	 * as writing the quota to disk may need the lock as well.
262 	 */
263 	dquot_initialize(inode);
264 	dquot_free_inode(inode);
265 	dquot_drop(inode);
266 
267 	is_directory = S_ISDIR(inode->i_mode);
268 
269 	/* Do this BEFORE marking the inode not in use or returning an error */
270 	ext4_clear_inode(inode);
271 
272 	es = sbi->s_es;
273 	if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
274 		ext4_error(sb, "reserved or nonexistent inode %lu", ino);
275 		goto error_return;
276 	}
277 	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
278 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
279 	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
280 	/* Don't bother if the inode bitmap is corrupt. */
281 	grp = ext4_get_group_info(sb, block_group);
282 	if (IS_ERR(bitmap_bh)) {
283 		fatal = PTR_ERR(bitmap_bh);
284 		bitmap_bh = NULL;
285 		goto error_return;
286 	}
287 	if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
288 		fatal = -EFSCORRUPTED;
289 		goto error_return;
290 	}
291 
292 	BUFFER_TRACE(bitmap_bh, "get_write_access");
293 	fatal = ext4_journal_get_write_access(handle, bitmap_bh);
294 	if (fatal)
295 		goto error_return;
296 
297 	fatal = -ESRCH;
298 	gdp = ext4_get_group_desc(sb, block_group, &bh2);
299 	if (gdp) {
300 		BUFFER_TRACE(bh2, "get_write_access");
301 		fatal = ext4_journal_get_write_access(handle, bh2);
302 	}
303 	ext4_lock_group(sb, block_group);
304 	cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
305 	if (fatal || !cleared) {
306 		ext4_unlock_group(sb, block_group);
307 		goto out;
308 	}
309 
310 	count = ext4_free_inodes_count(sb, gdp) + 1;
311 	ext4_free_inodes_set(sb, gdp, count);
312 	if (is_directory) {
313 		count = ext4_used_dirs_count(sb, gdp) - 1;
314 		ext4_used_dirs_set(sb, gdp, count);
315 		percpu_counter_dec(&sbi->s_dirs_counter);
316 	}
317 	ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
318 				   EXT4_INODES_PER_GROUP(sb) / 8);
319 	ext4_group_desc_csum_set(sb, block_group, gdp);
320 	ext4_unlock_group(sb, block_group);
321 
322 	percpu_counter_inc(&sbi->s_freeinodes_counter);
323 	if (sbi->s_log_groups_per_flex) {
324 		ext4_group_t f = ext4_flex_group(sbi, block_group);
325 
326 		atomic_inc(&sbi->s_flex_groups[f].free_inodes);
327 		if (is_directory)
328 			atomic_dec(&sbi->s_flex_groups[f].used_dirs);
329 	}
330 	BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
331 	fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
332 out:
333 	if (cleared) {
334 		BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
335 		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
336 		if (!fatal)
337 			fatal = err;
338 	} else {
339 		ext4_error(sb, "bit already cleared for inode %lu", ino);
340 		if (gdp && !EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
341 			int count;
342 			count = ext4_free_inodes_count(sb, gdp);
343 			percpu_counter_sub(&sbi->s_freeinodes_counter,
344 					   count);
345 		}
346 		set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
347 	}
348 
349 error_return:
350 	brelse(bitmap_bh);
351 	ext4_std_error(sb, fatal);
352 }
353 
354 struct orlov_stats {
355 	__u64 free_clusters;
356 	__u32 free_inodes;
357 	__u32 used_dirs;
358 };
359 
360 /*
361  * Helper function for Orlov's allocator; returns critical information
362  * for a particular block group or flex_bg.  If flex_size is 1, then g
363  * is a block group number; otherwise it is flex_bg number.
364  */
365 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
366 			    int flex_size, struct orlov_stats *stats)
367 {
368 	struct ext4_group_desc *desc;
369 	struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
370 
371 	if (flex_size > 1) {
372 		stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
373 		stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
374 		stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
375 		return;
376 	}
377 
378 	desc = ext4_get_group_desc(sb, g, NULL);
379 	if (desc) {
380 		stats->free_inodes = ext4_free_inodes_count(sb, desc);
381 		stats->free_clusters = ext4_free_group_clusters(sb, desc);
382 		stats->used_dirs = ext4_used_dirs_count(sb, desc);
383 	} else {
384 		stats->free_inodes = 0;
385 		stats->free_clusters = 0;
386 		stats->used_dirs = 0;
387 	}
388 }
389 
390 /*
391  * Orlov's allocator for directories.
392  *
393  * We always try to spread first-level directories.
394  *
395  * If there are blockgroups with both free inodes and free blocks counts
396  * not worse than average we return one with smallest directory count.
397  * Otherwise we simply return a random group.
398  *
399  * For the rest rules look so:
400  *
401  * It's OK to put directory into a group unless
402  * it has too many directories already (max_dirs) or
403  * it has too few free inodes left (min_inodes) or
404  * it has too few free blocks left (min_blocks) or
405  * Parent's group is preferred, if it doesn't satisfy these
406  * conditions we search cyclically through the rest. If none
407  * of the groups look good we just look for a group with more
408  * free inodes than average (starting at parent's group).
409  */
410 
411 static int find_group_orlov(struct super_block *sb, struct inode *parent,
412 			    ext4_group_t *group, umode_t mode,
413 			    const struct qstr *qstr)
414 {
415 	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
416 	struct ext4_sb_info *sbi = EXT4_SB(sb);
417 	ext4_group_t real_ngroups = ext4_get_groups_count(sb);
418 	int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
419 	unsigned int freei, avefreei, grp_free;
420 	ext4_fsblk_t freeb, avefreec;
421 	unsigned int ndirs;
422 	int max_dirs, min_inodes;
423 	ext4_grpblk_t min_clusters;
424 	ext4_group_t i, grp, g, ngroups;
425 	struct ext4_group_desc *desc;
426 	struct orlov_stats stats;
427 	int flex_size = ext4_flex_bg_size(sbi);
428 	struct dx_hash_info hinfo;
429 
430 	ngroups = real_ngroups;
431 	if (flex_size > 1) {
432 		ngroups = (real_ngroups + flex_size - 1) >>
433 			sbi->s_log_groups_per_flex;
434 		parent_group >>= sbi->s_log_groups_per_flex;
435 	}
436 
437 	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
438 	avefreei = freei / ngroups;
439 	freeb = EXT4_C2B(sbi,
440 		percpu_counter_read_positive(&sbi->s_freeclusters_counter));
441 	avefreec = freeb;
442 	do_div(avefreec, ngroups);
443 	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
444 
445 	if (S_ISDIR(mode) &&
446 	    ((parent == d_inode(sb->s_root)) ||
447 	     (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
448 		int best_ndir = inodes_per_group;
449 		int ret = -1;
450 
451 		if (qstr) {
452 			hinfo.hash_version = DX_HASH_HALF_MD4;
453 			hinfo.seed = sbi->s_hash_seed;
454 			ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
455 			grp = hinfo.hash;
456 		} else
457 			grp = prandom_u32();
458 		parent_group = (unsigned)grp % ngroups;
459 		for (i = 0; i < ngroups; i++) {
460 			g = (parent_group + i) % ngroups;
461 			get_orlov_stats(sb, g, flex_size, &stats);
462 			if (!stats.free_inodes)
463 				continue;
464 			if (stats.used_dirs >= best_ndir)
465 				continue;
466 			if (stats.free_inodes < avefreei)
467 				continue;
468 			if (stats.free_clusters < avefreec)
469 				continue;
470 			grp = g;
471 			ret = 0;
472 			best_ndir = stats.used_dirs;
473 		}
474 		if (ret)
475 			goto fallback;
476 	found_flex_bg:
477 		if (flex_size == 1) {
478 			*group = grp;
479 			return 0;
480 		}
481 
482 		/*
483 		 * We pack inodes at the beginning of the flexgroup's
484 		 * inode tables.  Block allocation decisions will do
485 		 * something similar, although regular files will
486 		 * start at 2nd block group of the flexgroup.  See
487 		 * ext4_ext_find_goal() and ext4_find_near().
488 		 */
489 		grp *= flex_size;
490 		for (i = 0; i < flex_size; i++) {
491 			if (grp+i >= real_ngroups)
492 				break;
493 			desc = ext4_get_group_desc(sb, grp+i, NULL);
494 			if (desc && ext4_free_inodes_count(sb, desc)) {
495 				*group = grp+i;
496 				return 0;
497 			}
498 		}
499 		goto fallback;
500 	}
501 
502 	max_dirs = ndirs / ngroups + inodes_per_group / 16;
503 	min_inodes = avefreei - inodes_per_group*flex_size / 4;
504 	if (min_inodes < 1)
505 		min_inodes = 1;
506 	min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
507 
508 	/*
509 	 * Start looking in the flex group where we last allocated an
510 	 * inode for this parent directory
511 	 */
512 	if (EXT4_I(parent)->i_last_alloc_group != ~0) {
513 		parent_group = EXT4_I(parent)->i_last_alloc_group;
514 		if (flex_size > 1)
515 			parent_group >>= sbi->s_log_groups_per_flex;
516 	}
517 
518 	for (i = 0; i < ngroups; i++) {
519 		grp = (parent_group + i) % ngroups;
520 		get_orlov_stats(sb, grp, flex_size, &stats);
521 		if (stats.used_dirs >= max_dirs)
522 			continue;
523 		if (stats.free_inodes < min_inodes)
524 			continue;
525 		if (stats.free_clusters < min_clusters)
526 			continue;
527 		goto found_flex_bg;
528 	}
529 
530 fallback:
531 	ngroups = real_ngroups;
532 	avefreei = freei / ngroups;
533 fallback_retry:
534 	parent_group = EXT4_I(parent)->i_block_group;
535 	for (i = 0; i < ngroups; i++) {
536 		grp = (parent_group + i) % ngroups;
537 		desc = ext4_get_group_desc(sb, grp, NULL);
538 		if (desc) {
539 			grp_free = ext4_free_inodes_count(sb, desc);
540 			if (grp_free && grp_free >= avefreei) {
541 				*group = grp;
542 				return 0;
543 			}
544 		}
545 	}
546 
547 	if (avefreei) {
548 		/*
549 		 * The free-inodes counter is approximate, and for really small
550 		 * filesystems the above test can fail to find any blockgroups
551 		 */
552 		avefreei = 0;
553 		goto fallback_retry;
554 	}
555 
556 	return -1;
557 }
558 
559 static int find_group_other(struct super_block *sb, struct inode *parent,
560 			    ext4_group_t *group, umode_t mode)
561 {
562 	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
563 	ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
564 	struct ext4_group_desc *desc;
565 	int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
566 
567 	/*
568 	 * Try to place the inode is the same flex group as its
569 	 * parent.  If we can't find space, use the Orlov algorithm to
570 	 * find another flex group, and store that information in the
571 	 * parent directory's inode information so that use that flex
572 	 * group for future allocations.
573 	 */
574 	if (flex_size > 1) {
575 		int retry = 0;
576 
577 	try_again:
578 		parent_group &= ~(flex_size-1);
579 		last = parent_group + flex_size;
580 		if (last > ngroups)
581 			last = ngroups;
582 		for  (i = parent_group; i < last; i++) {
583 			desc = ext4_get_group_desc(sb, i, NULL);
584 			if (desc && ext4_free_inodes_count(sb, desc)) {
585 				*group = i;
586 				return 0;
587 			}
588 		}
589 		if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
590 			retry = 1;
591 			parent_group = EXT4_I(parent)->i_last_alloc_group;
592 			goto try_again;
593 		}
594 		/*
595 		 * If this didn't work, use the Orlov search algorithm
596 		 * to find a new flex group; we pass in the mode to
597 		 * avoid the topdir algorithms.
598 		 */
599 		*group = parent_group + flex_size;
600 		if (*group > ngroups)
601 			*group = 0;
602 		return find_group_orlov(sb, parent, group, mode, NULL);
603 	}
604 
605 	/*
606 	 * Try to place the inode in its parent directory
607 	 */
608 	*group = parent_group;
609 	desc = ext4_get_group_desc(sb, *group, NULL);
610 	if (desc && ext4_free_inodes_count(sb, desc) &&
611 	    ext4_free_group_clusters(sb, desc))
612 		return 0;
613 
614 	/*
615 	 * We're going to place this inode in a different blockgroup from its
616 	 * parent.  We want to cause files in a common directory to all land in
617 	 * the same blockgroup.  But we want files which are in a different
618 	 * directory which shares a blockgroup with our parent to land in a
619 	 * different blockgroup.
620 	 *
621 	 * So add our directory's i_ino into the starting point for the hash.
622 	 */
623 	*group = (*group + parent->i_ino) % ngroups;
624 
625 	/*
626 	 * Use a quadratic hash to find a group with a free inode and some free
627 	 * blocks.
628 	 */
629 	for (i = 1; i < ngroups; i <<= 1) {
630 		*group += i;
631 		if (*group >= ngroups)
632 			*group -= ngroups;
633 		desc = ext4_get_group_desc(sb, *group, NULL);
634 		if (desc && ext4_free_inodes_count(sb, desc) &&
635 		    ext4_free_group_clusters(sb, desc))
636 			return 0;
637 	}
638 
639 	/*
640 	 * That failed: try linear search for a free inode, even if that group
641 	 * has no free blocks.
642 	 */
643 	*group = parent_group;
644 	for (i = 0; i < ngroups; i++) {
645 		if (++*group >= ngroups)
646 			*group = 0;
647 		desc = ext4_get_group_desc(sb, *group, NULL);
648 		if (desc && ext4_free_inodes_count(sb, desc))
649 			return 0;
650 	}
651 
652 	return -1;
653 }
654 
655 /*
656  * In no journal mode, if an inode has recently been deleted, we want
657  * to avoid reusing it until we're reasonably sure the inode table
658  * block has been written back to disk.  (Yes, these values are
659  * somewhat arbitrary...)
660  */
661 #define RECENTCY_MIN	5
662 #define RECENTCY_DIRTY	300
663 
664 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
665 {
666 	struct ext4_group_desc	*gdp;
667 	struct ext4_inode	*raw_inode;
668 	struct buffer_head	*bh;
669 	int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
670 	int offset, ret = 0;
671 	int recentcy = RECENTCY_MIN;
672 	u32 dtime, now;
673 
674 	gdp = ext4_get_group_desc(sb, group, NULL);
675 	if (unlikely(!gdp))
676 		return 0;
677 
678 	bh = sb_find_get_block(sb, ext4_inode_table(sb, gdp) +
679 		       (ino / inodes_per_block));
680 	if (!bh || !buffer_uptodate(bh))
681 		/*
682 		 * If the block is not in the buffer cache, then it
683 		 * must have been written out.
684 		 */
685 		goto out;
686 
687 	offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
688 	raw_inode = (struct ext4_inode *) (bh->b_data + offset);
689 
690 	/* i_dtime is only 32 bits on disk, but we only care about relative
691 	 * times in the range of a few minutes (i.e. long enough to sync a
692 	 * recently-deleted inode to disk), so using the low 32 bits of the
693 	 * clock (a 68 year range) is enough, see time_before32() */
694 	dtime = le32_to_cpu(raw_inode->i_dtime);
695 	now = ktime_get_real_seconds();
696 	if (buffer_dirty(bh))
697 		recentcy += RECENTCY_DIRTY;
698 
699 	if (dtime && time_before32(dtime, now) &&
700 	    time_before32(now, dtime + recentcy))
701 		ret = 1;
702 out:
703 	brelse(bh);
704 	return ret;
705 }
706 
707 static int find_inode_bit(struct super_block *sb, ext4_group_t group,
708 			  struct buffer_head *bitmap, unsigned long *ino)
709 {
710 next:
711 	*ino = ext4_find_next_zero_bit((unsigned long *)
712 				       bitmap->b_data,
713 				       EXT4_INODES_PER_GROUP(sb), *ino);
714 	if (*ino >= EXT4_INODES_PER_GROUP(sb))
715 		return 0;
716 
717 	if ((EXT4_SB(sb)->s_journal == NULL) &&
718 	    recently_deleted(sb, group, *ino)) {
719 		*ino = *ino + 1;
720 		if (*ino < EXT4_INODES_PER_GROUP(sb))
721 			goto next;
722 		return 0;
723 	}
724 
725 	return 1;
726 }
727 
728 /*
729  * There are two policies for allocating an inode.  If the new inode is
730  * a directory, then a forward search is made for a block group with both
731  * free space and a low directory-to-inode ratio; if that fails, then of
732  * the groups with above-average free space, that group with the fewest
733  * directories already is chosen.
734  *
735  * For other inodes, search forward from the parent directory's block
736  * group to find a free inode.
737  */
738 struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
739 			       umode_t mode, const struct qstr *qstr,
740 			       __u32 goal, uid_t *owner, __u32 i_flags,
741 			       int handle_type, unsigned int line_no,
742 			       int nblocks)
743 {
744 	struct super_block *sb;
745 	struct buffer_head *inode_bitmap_bh = NULL;
746 	struct buffer_head *group_desc_bh;
747 	ext4_group_t ngroups, group = 0;
748 	unsigned long ino = 0;
749 	struct inode *inode;
750 	struct ext4_group_desc *gdp = NULL;
751 	struct ext4_inode_info *ei;
752 	struct ext4_sb_info *sbi;
753 	int ret2, err;
754 	struct inode *ret;
755 	ext4_group_t i;
756 	ext4_group_t flex_group;
757 	struct ext4_group_info *grp;
758 	int encrypt = 0;
759 
760 	/* Cannot create files in a deleted directory */
761 	if (!dir || !dir->i_nlink)
762 		return ERR_PTR(-EPERM);
763 
764 	sb = dir->i_sb;
765 	sbi = EXT4_SB(sb);
766 
767 	if (unlikely(ext4_forced_shutdown(sbi)))
768 		return ERR_PTR(-EIO);
769 
770 	if ((ext4_encrypted_inode(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) &&
771 	    (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) &&
772 	    !(i_flags & EXT4_EA_INODE_FL)) {
773 		err = fscrypt_get_encryption_info(dir);
774 		if (err)
775 			return ERR_PTR(err);
776 		if (!fscrypt_has_encryption_key(dir))
777 			return ERR_PTR(-ENOKEY);
778 		encrypt = 1;
779 	}
780 
781 	if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
782 #ifdef CONFIG_EXT4_FS_POSIX_ACL
783 		struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
784 
785 		if (IS_ERR(p))
786 			return ERR_CAST(p);
787 		if (p) {
788 			int acl_size = p->a_count * sizeof(ext4_acl_entry);
789 
790 			nblocks += (S_ISDIR(mode) ? 2 : 1) *
791 				__ext4_xattr_set_credits(sb, NULL /* inode */,
792 					NULL /* block_bh */, acl_size,
793 					true /* is_create */);
794 			posix_acl_release(p);
795 		}
796 #endif
797 
798 #ifdef CONFIG_SECURITY
799 		{
800 			int num_security_xattrs = 1;
801 
802 #ifdef CONFIG_INTEGRITY
803 			num_security_xattrs++;
804 #endif
805 			/*
806 			 * We assume that security xattrs are never
807 			 * more than 1k.  In practice they are under
808 			 * 128 bytes.
809 			 */
810 			nblocks += num_security_xattrs *
811 				__ext4_xattr_set_credits(sb, NULL /* inode */,
812 					NULL /* block_bh */, 1024,
813 					true /* is_create */);
814 		}
815 #endif
816 		if (encrypt)
817 			nblocks += __ext4_xattr_set_credits(sb,
818 					NULL /* inode */, NULL /* block_bh */,
819 					FSCRYPT_SET_CONTEXT_MAX_SIZE,
820 					true /* is_create */);
821 	}
822 
823 	ngroups = ext4_get_groups_count(sb);
824 	trace_ext4_request_inode(dir, mode);
825 	inode = new_inode(sb);
826 	if (!inode)
827 		return ERR_PTR(-ENOMEM);
828 	ei = EXT4_I(inode);
829 
830 	/*
831 	 * Initialize owners and quota early so that we don't have to account
832 	 * for quota initialization worst case in standard inode creating
833 	 * transaction
834 	 */
835 	if (owner) {
836 		inode->i_mode = mode;
837 		i_uid_write(inode, owner[0]);
838 		i_gid_write(inode, owner[1]);
839 	} else if (test_opt(sb, GRPID)) {
840 		inode->i_mode = mode;
841 		inode->i_uid = current_fsuid();
842 		inode->i_gid = dir->i_gid;
843 	} else
844 		inode_init_owner(inode, dir, mode);
845 
846 	if (ext4_has_feature_project(sb) &&
847 	    ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
848 		ei->i_projid = EXT4_I(dir)->i_projid;
849 	else
850 		ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
851 
852 	err = dquot_initialize(inode);
853 	if (err)
854 		goto out;
855 
856 	if (!goal)
857 		goal = sbi->s_inode_goal;
858 
859 	if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
860 		group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
861 		ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
862 		ret2 = 0;
863 		goto got_group;
864 	}
865 
866 	if (S_ISDIR(mode))
867 		ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
868 	else
869 		ret2 = find_group_other(sb, dir, &group, mode);
870 
871 got_group:
872 	EXT4_I(dir)->i_last_alloc_group = group;
873 	err = -ENOSPC;
874 	if (ret2 == -1)
875 		goto out;
876 
877 	/*
878 	 * Normally we will only go through one pass of this loop,
879 	 * unless we get unlucky and it turns out the group we selected
880 	 * had its last inode grabbed by someone else.
881 	 */
882 	for (i = 0; i < ngroups; i++, ino = 0) {
883 		err = -EIO;
884 
885 		gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
886 		if (!gdp)
887 			goto out;
888 
889 		/*
890 		 * Check free inodes count before loading bitmap.
891 		 */
892 		if (ext4_free_inodes_count(sb, gdp) == 0)
893 			goto next_group;
894 
895 		grp = ext4_get_group_info(sb, group);
896 		/* Skip groups with already-known suspicious inode tables */
897 		if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
898 			goto next_group;
899 
900 		brelse(inode_bitmap_bh);
901 		inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
902 		/* Skip groups with suspicious inode tables */
903 		if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
904 		    IS_ERR(inode_bitmap_bh)) {
905 			inode_bitmap_bh = NULL;
906 			goto next_group;
907 		}
908 
909 repeat_in_this_group:
910 		ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
911 		if (!ret2)
912 			goto next_group;
913 
914 		if (group == 0 && (ino + 1) < EXT4_FIRST_INO(sb)) {
915 			ext4_error(sb, "reserved inode found cleared - "
916 				   "inode=%lu", ino + 1);
917 			goto next_group;
918 		}
919 
920 		if (!handle) {
921 			BUG_ON(nblocks <= 0);
922 			handle = __ext4_journal_start_sb(dir->i_sb, line_no,
923 							 handle_type, nblocks,
924 							 0);
925 			if (IS_ERR(handle)) {
926 				err = PTR_ERR(handle);
927 				ext4_std_error(sb, err);
928 				goto out;
929 			}
930 		}
931 		BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
932 		err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
933 		if (err) {
934 			ext4_std_error(sb, err);
935 			goto out;
936 		}
937 		ext4_lock_group(sb, group);
938 		ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
939 		if (ret2) {
940 			/* Someone already took the bit. Repeat the search
941 			 * with lock held.
942 			 */
943 			ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
944 			if (ret2) {
945 				ext4_set_bit(ino, inode_bitmap_bh->b_data);
946 				ret2 = 0;
947 			} else {
948 				ret2 = 1; /* we didn't grab the inode */
949 			}
950 		}
951 		ext4_unlock_group(sb, group);
952 		ino++;		/* the inode bitmap is zero-based */
953 		if (!ret2)
954 			goto got; /* we grabbed the inode! */
955 
956 		if (ino < EXT4_INODES_PER_GROUP(sb))
957 			goto repeat_in_this_group;
958 next_group:
959 		if (++group == ngroups)
960 			group = 0;
961 	}
962 	err = -ENOSPC;
963 	goto out;
964 
965 got:
966 	BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
967 	err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
968 	if (err) {
969 		ext4_std_error(sb, err);
970 		goto out;
971 	}
972 
973 	BUFFER_TRACE(group_desc_bh, "get_write_access");
974 	err = ext4_journal_get_write_access(handle, group_desc_bh);
975 	if (err) {
976 		ext4_std_error(sb, err);
977 		goto out;
978 	}
979 
980 	/* We may have to initialize the block bitmap if it isn't already */
981 	if (ext4_has_group_desc_csum(sb) &&
982 	    gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
983 		struct buffer_head *block_bitmap_bh;
984 
985 		block_bitmap_bh = ext4_read_block_bitmap(sb, group);
986 		if (IS_ERR(block_bitmap_bh)) {
987 			err = PTR_ERR(block_bitmap_bh);
988 			goto out;
989 		}
990 		BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
991 		err = ext4_journal_get_write_access(handle, block_bitmap_bh);
992 		if (err) {
993 			brelse(block_bitmap_bh);
994 			ext4_std_error(sb, err);
995 			goto out;
996 		}
997 
998 		BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
999 		err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
1000 
1001 		/* recheck and clear flag under lock if we still need to */
1002 		ext4_lock_group(sb, group);
1003 		if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
1004 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
1005 			ext4_free_group_clusters_set(sb, gdp,
1006 				ext4_free_clusters_after_init(sb, group, gdp));
1007 			ext4_block_bitmap_csum_set(sb, group, gdp,
1008 						   block_bitmap_bh);
1009 			ext4_group_desc_csum_set(sb, group, gdp);
1010 		}
1011 		ext4_unlock_group(sb, group);
1012 		brelse(block_bitmap_bh);
1013 
1014 		if (err) {
1015 			ext4_std_error(sb, err);
1016 			goto out;
1017 		}
1018 	}
1019 
1020 	/* Update the relevant bg descriptor fields */
1021 	if (ext4_has_group_desc_csum(sb)) {
1022 		int free;
1023 		struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1024 
1025 		down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
1026 		ext4_lock_group(sb, group); /* while we modify the bg desc */
1027 		free = EXT4_INODES_PER_GROUP(sb) -
1028 			ext4_itable_unused_count(sb, gdp);
1029 		if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
1030 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
1031 			free = 0;
1032 		}
1033 		/*
1034 		 * Check the relative inode number against the last used
1035 		 * relative inode number in this group. if it is greater
1036 		 * we need to update the bg_itable_unused count
1037 		 */
1038 		if (ino > free)
1039 			ext4_itable_unused_set(sb, gdp,
1040 					(EXT4_INODES_PER_GROUP(sb) - ino));
1041 		up_read(&grp->alloc_sem);
1042 	} else {
1043 		ext4_lock_group(sb, group);
1044 	}
1045 
1046 	ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1047 	if (S_ISDIR(mode)) {
1048 		ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1049 		if (sbi->s_log_groups_per_flex) {
1050 			ext4_group_t f = ext4_flex_group(sbi, group);
1051 
1052 			atomic_inc(&sbi->s_flex_groups[f].used_dirs);
1053 		}
1054 	}
1055 	if (ext4_has_group_desc_csum(sb)) {
1056 		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1057 					   EXT4_INODES_PER_GROUP(sb) / 8);
1058 		ext4_group_desc_csum_set(sb, group, gdp);
1059 	}
1060 	ext4_unlock_group(sb, group);
1061 
1062 	BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1063 	err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1064 	if (err) {
1065 		ext4_std_error(sb, err);
1066 		goto out;
1067 	}
1068 
1069 	percpu_counter_dec(&sbi->s_freeinodes_counter);
1070 	if (S_ISDIR(mode))
1071 		percpu_counter_inc(&sbi->s_dirs_counter);
1072 
1073 	if (sbi->s_log_groups_per_flex) {
1074 		flex_group = ext4_flex_group(sbi, group);
1075 		atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
1076 	}
1077 
1078 	inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1079 	/* This is the optimal IO size (for stat), not the fs block size */
1080 	inode->i_blocks = 0;
1081 	inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
1082 						       current_time(inode);
1083 
1084 	memset(ei->i_data, 0, sizeof(ei->i_data));
1085 	ei->i_dir_start_lookup = 0;
1086 	ei->i_disksize = 0;
1087 
1088 	/* Don't inherit extent flag from directory, amongst others. */
1089 	ei->i_flags =
1090 		ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1091 	ei->i_flags |= i_flags;
1092 	ei->i_file_acl = 0;
1093 	ei->i_dtime = 0;
1094 	ei->i_block_group = group;
1095 	ei->i_last_alloc_group = ~0;
1096 
1097 	ext4_set_inode_flags(inode);
1098 	if (IS_DIRSYNC(inode))
1099 		ext4_handle_sync(handle);
1100 	if (insert_inode_locked(inode) < 0) {
1101 		/*
1102 		 * Likely a bitmap corruption causing inode to be allocated
1103 		 * twice.
1104 		 */
1105 		err = -EIO;
1106 		ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1107 			   inode->i_ino);
1108 		goto out;
1109 	}
1110 	inode->i_generation = prandom_u32();
1111 
1112 	/* Precompute checksum seed for inode metadata */
1113 	if (ext4_has_metadata_csum(sb)) {
1114 		__u32 csum;
1115 		__le32 inum = cpu_to_le32(inode->i_ino);
1116 		__le32 gen = cpu_to_le32(inode->i_generation);
1117 		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1118 				   sizeof(inum));
1119 		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1120 					      sizeof(gen));
1121 	}
1122 
1123 	ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1124 	ext4_set_inode_state(inode, EXT4_STATE_NEW);
1125 
1126 	ei->i_extra_isize = sbi->s_want_extra_isize;
1127 	ei->i_inline_off = 0;
1128 	if (ext4_has_feature_inline_data(sb))
1129 		ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1130 	ret = inode;
1131 	err = dquot_alloc_inode(inode);
1132 	if (err)
1133 		goto fail_drop;
1134 
1135 	/*
1136 	 * Since the encryption xattr will always be unique, create it first so
1137 	 * that it's less likely to end up in an external xattr block and
1138 	 * prevent its deduplication.
1139 	 */
1140 	if (encrypt) {
1141 		err = fscrypt_inherit_context(dir, inode, handle, true);
1142 		if (err)
1143 			goto fail_free_drop;
1144 	}
1145 
1146 	if (!(ei->i_flags & EXT4_EA_INODE_FL)) {
1147 		err = ext4_init_acl(handle, inode, dir);
1148 		if (err)
1149 			goto fail_free_drop;
1150 
1151 		err = ext4_init_security(handle, inode, dir, qstr);
1152 		if (err)
1153 			goto fail_free_drop;
1154 	}
1155 
1156 	if (ext4_has_feature_extents(sb)) {
1157 		/* set extent flag only for directory, file and normal symlink*/
1158 		if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1159 			ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1160 			ext4_ext_tree_init(handle, inode);
1161 		}
1162 	}
1163 
1164 	if (ext4_handle_valid(handle)) {
1165 		ei->i_sync_tid = handle->h_transaction->t_tid;
1166 		ei->i_datasync_tid = handle->h_transaction->t_tid;
1167 	}
1168 
1169 	err = ext4_mark_inode_dirty(handle, inode);
1170 	if (err) {
1171 		ext4_std_error(sb, err);
1172 		goto fail_free_drop;
1173 	}
1174 
1175 	ext4_debug("allocating inode %lu\n", inode->i_ino);
1176 	trace_ext4_allocate_inode(inode, dir, mode);
1177 	brelse(inode_bitmap_bh);
1178 	return ret;
1179 
1180 fail_free_drop:
1181 	dquot_free_inode(inode);
1182 fail_drop:
1183 	clear_nlink(inode);
1184 	unlock_new_inode(inode);
1185 out:
1186 	dquot_drop(inode);
1187 	inode->i_flags |= S_NOQUOTA;
1188 	iput(inode);
1189 	brelse(inode_bitmap_bh);
1190 	return ERR_PTR(err);
1191 }
1192 
1193 /* Verify that we are loading a valid orphan from disk */
1194 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1195 {
1196 	unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1197 	ext4_group_t block_group;
1198 	int bit;
1199 	struct buffer_head *bitmap_bh = NULL;
1200 	struct inode *inode = NULL;
1201 	int err = -EFSCORRUPTED;
1202 
1203 	if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
1204 		goto bad_orphan;
1205 
1206 	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1207 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1208 	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1209 	if (IS_ERR(bitmap_bh)) {
1210 		ext4_error(sb, "inode bitmap error %ld for orphan %lu",
1211 			   ino, PTR_ERR(bitmap_bh));
1212 		return (struct inode *) bitmap_bh;
1213 	}
1214 
1215 	/* Having the inode bit set should be a 100% indicator that this
1216 	 * is a valid orphan (no e2fsck run on fs).  Orphans also include
1217 	 * inodes that were being truncated, so we can't check i_nlink==0.
1218 	 */
1219 	if (!ext4_test_bit(bit, bitmap_bh->b_data))
1220 		goto bad_orphan;
1221 
1222 	inode = ext4_iget(sb, ino);
1223 	if (IS_ERR(inode)) {
1224 		err = PTR_ERR(inode);
1225 		ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
1226 			   ino, err);
1227 		return inode;
1228 	}
1229 
1230 	/*
1231 	 * If the orphans has i_nlinks > 0 then it should be able to
1232 	 * be truncated, otherwise it won't be removed from the orphan
1233 	 * list during processing and an infinite loop will result.
1234 	 * Similarly, it must not be a bad inode.
1235 	 */
1236 	if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
1237 	    is_bad_inode(inode))
1238 		goto bad_orphan;
1239 
1240 	if (NEXT_ORPHAN(inode) > max_ino)
1241 		goto bad_orphan;
1242 	brelse(bitmap_bh);
1243 	return inode;
1244 
1245 bad_orphan:
1246 	ext4_error(sb, "bad orphan inode %lu", ino);
1247 	if (bitmap_bh)
1248 		printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1249 		       bit, (unsigned long long)bitmap_bh->b_blocknr,
1250 		       ext4_test_bit(bit, bitmap_bh->b_data));
1251 	if (inode) {
1252 		printk(KERN_ERR "is_bad_inode(inode)=%d\n",
1253 		       is_bad_inode(inode));
1254 		printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
1255 		       NEXT_ORPHAN(inode));
1256 		printk(KERN_ERR "max_ino=%lu\n", max_ino);
1257 		printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
1258 		/* Avoid freeing blocks if we got a bad deleted inode */
1259 		if (inode->i_nlink == 0)
1260 			inode->i_blocks = 0;
1261 		iput(inode);
1262 	}
1263 	brelse(bitmap_bh);
1264 	return ERR_PTR(err);
1265 }
1266 
1267 unsigned long ext4_count_free_inodes(struct super_block *sb)
1268 {
1269 	unsigned long desc_count;
1270 	struct ext4_group_desc *gdp;
1271 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1272 #ifdef EXT4FS_DEBUG
1273 	struct ext4_super_block *es;
1274 	unsigned long bitmap_count, x;
1275 	struct buffer_head *bitmap_bh = NULL;
1276 
1277 	es = EXT4_SB(sb)->s_es;
1278 	desc_count = 0;
1279 	bitmap_count = 0;
1280 	gdp = NULL;
1281 	for (i = 0; i < ngroups; i++) {
1282 		gdp = ext4_get_group_desc(sb, i, NULL);
1283 		if (!gdp)
1284 			continue;
1285 		desc_count += ext4_free_inodes_count(sb, gdp);
1286 		brelse(bitmap_bh);
1287 		bitmap_bh = ext4_read_inode_bitmap(sb, i);
1288 		if (IS_ERR(bitmap_bh)) {
1289 			bitmap_bh = NULL;
1290 			continue;
1291 		}
1292 
1293 		x = ext4_count_free(bitmap_bh->b_data,
1294 				    EXT4_INODES_PER_GROUP(sb) / 8);
1295 		printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1296 			(unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1297 		bitmap_count += x;
1298 	}
1299 	brelse(bitmap_bh);
1300 	printk(KERN_DEBUG "ext4_count_free_inodes: "
1301 	       "stored = %u, computed = %lu, %lu\n",
1302 	       le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1303 	return desc_count;
1304 #else
1305 	desc_count = 0;
1306 	for (i = 0; i < ngroups; i++) {
1307 		gdp = ext4_get_group_desc(sb, i, NULL);
1308 		if (!gdp)
1309 			continue;
1310 		desc_count += ext4_free_inodes_count(sb, gdp);
1311 		cond_resched();
1312 	}
1313 	return desc_count;
1314 #endif
1315 }
1316 
1317 /* Called at mount-time, super-block is locked */
1318 unsigned long ext4_count_dirs(struct super_block * sb)
1319 {
1320 	unsigned long count = 0;
1321 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1322 
1323 	for (i = 0; i < ngroups; i++) {
1324 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1325 		if (!gdp)
1326 			continue;
1327 		count += ext4_used_dirs_count(sb, gdp);
1328 	}
1329 	return count;
1330 }
1331 
1332 /*
1333  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1334  * inode table. Must be called without any spinlock held. The only place
1335  * where it is called from on active part of filesystem is ext4lazyinit
1336  * thread, so we do not need any special locks, however we have to prevent
1337  * inode allocation from the current group, so we take alloc_sem lock, to
1338  * block ext4_new_inode() until we are finished.
1339  */
1340 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1341 				 int barrier)
1342 {
1343 	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1344 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1345 	struct ext4_group_desc *gdp = NULL;
1346 	struct buffer_head *group_desc_bh;
1347 	handle_t *handle;
1348 	ext4_fsblk_t blk;
1349 	int num, ret = 0, used_blks = 0;
1350 
1351 	/* This should not happen, but just to be sure check this */
1352 	if (sb_rdonly(sb)) {
1353 		ret = 1;
1354 		goto out;
1355 	}
1356 
1357 	gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1358 	if (!gdp)
1359 		goto out;
1360 
1361 	/*
1362 	 * We do not need to lock this, because we are the only one
1363 	 * handling this flag.
1364 	 */
1365 	if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1366 		goto out;
1367 
1368 	handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1369 	if (IS_ERR(handle)) {
1370 		ret = PTR_ERR(handle);
1371 		goto out;
1372 	}
1373 
1374 	down_write(&grp->alloc_sem);
1375 	/*
1376 	 * If inode bitmap was already initialized there may be some
1377 	 * used inodes so we need to skip blocks with used inodes in
1378 	 * inode table.
1379 	 */
1380 	if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1381 		used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1382 			    ext4_itable_unused_count(sb, gdp)),
1383 			    sbi->s_inodes_per_block);
1384 
1385 	if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1386 		ext4_error(sb, "Something is wrong with group %u: "
1387 			   "used itable blocks: %d; "
1388 			   "itable unused count: %u",
1389 			   group, used_blks,
1390 			   ext4_itable_unused_count(sb, gdp));
1391 		ret = 1;
1392 		goto err_out;
1393 	}
1394 
1395 	blk = ext4_inode_table(sb, gdp) + used_blks;
1396 	num = sbi->s_itb_per_group - used_blks;
1397 
1398 	BUFFER_TRACE(group_desc_bh, "get_write_access");
1399 	ret = ext4_journal_get_write_access(handle,
1400 					    group_desc_bh);
1401 	if (ret)
1402 		goto err_out;
1403 
1404 	/*
1405 	 * Skip zeroout if the inode table is full. But we set the ZEROED
1406 	 * flag anyway, because obviously, when it is full it does not need
1407 	 * further zeroing.
1408 	 */
1409 	if (unlikely(num == 0))
1410 		goto skip_zeroout;
1411 
1412 	ext4_debug("going to zero out inode table in group %d\n",
1413 		   group);
1414 	ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1415 	if (ret < 0)
1416 		goto err_out;
1417 	if (barrier)
1418 		blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1419 
1420 skip_zeroout:
1421 	ext4_lock_group(sb, group);
1422 	gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1423 	ext4_group_desc_csum_set(sb, group, gdp);
1424 	ext4_unlock_group(sb, group);
1425 
1426 	BUFFER_TRACE(group_desc_bh,
1427 		     "call ext4_handle_dirty_metadata");
1428 	ret = ext4_handle_dirty_metadata(handle, NULL,
1429 					 group_desc_bh);
1430 
1431 err_out:
1432 	up_write(&grp->alloc_sem);
1433 	ext4_journal_stop(handle);
1434 out:
1435 	return ret;
1436 }
1437