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  */
ext4_mark_bitmap_end(int start_bit,int end_bit,char * bitmap)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 
ext4_end_bitmap_read(struct buffer_head * bh,int uptodate)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 
ext4_validate_inode_bitmap(struct super_block * sb,struct ext4_group_desc * desc,ext4_group_t block_group,struct buffer_head * bh)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 
87 	if (buffer_verified(bh))
88 		return 0;
89 	if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
90 		return -EFSCORRUPTED;
91 
92 	ext4_lock_group(sb, block_group);
93 	if (buffer_verified(bh))
94 		goto verified;
95 	blk = ext4_inode_bitmap(sb, desc);
96 	if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
97 					   EXT4_INODES_PER_GROUP(sb) / 8)) {
98 		ext4_unlock_group(sb, block_group);
99 		ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
100 			   "inode_bitmap = %llu", block_group, blk);
101 		ext4_mark_group_bitmap_corrupted(sb, block_group,
102 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
103 		return -EFSBADCRC;
104 	}
105 	set_buffer_verified(bh);
106 verified:
107 	ext4_unlock_group(sb, block_group);
108 	return 0;
109 }
110 
111 /*
112  * Read the inode allocation bitmap for a given block_group, reading
113  * into the specified slot in the superblock's bitmap cache.
114  *
115  * Return buffer_head of bitmap on success or NULL.
116  */
117 static struct buffer_head *
ext4_read_inode_bitmap(struct super_block * sb,ext4_group_t block_group)118 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
119 {
120 	struct ext4_group_desc *desc;
121 	struct ext4_sb_info *sbi = EXT4_SB(sb);
122 	struct buffer_head *bh = NULL;
123 	ext4_fsblk_t bitmap_blk;
124 	int err;
125 
126 	desc = ext4_get_group_desc(sb, block_group, NULL);
127 	if (!desc)
128 		return ERR_PTR(-EFSCORRUPTED);
129 
130 	bitmap_blk = ext4_inode_bitmap(sb, desc);
131 	if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
132 	    (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
133 		ext4_error(sb, "Invalid inode bitmap blk %llu in "
134 			   "block_group %u", bitmap_blk, block_group);
135 		ext4_mark_group_bitmap_corrupted(sb, block_group,
136 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
137 		return ERR_PTR(-EFSCORRUPTED);
138 	}
139 	bh = sb_getblk(sb, bitmap_blk);
140 	if (unlikely(!bh)) {
141 		ext4_warning(sb, "Cannot read inode bitmap - "
142 			     "block_group = %u, inode_bitmap = %llu",
143 			     block_group, bitmap_blk);
144 		return ERR_PTR(-ENOMEM);
145 	}
146 	if (bitmap_uptodate(bh))
147 		goto verify;
148 
149 	lock_buffer(bh);
150 	if (bitmap_uptodate(bh)) {
151 		unlock_buffer(bh);
152 		goto verify;
153 	}
154 
155 	ext4_lock_group(sb, block_group);
156 	if (ext4_has_group_desc_csum(sb) &&
157 	    (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
158 		if (block_group == 0) {
159 			ext4_unlock_group(sb, block_group);
160 			unlock_buffer(bh);
161 			ext4_error(sb, "Inode bitmap for bg 0 marked "
162 				   "uninitialized");
163 			err = -EFSCORRUPTED;
164 			goto out;
165 		}
166 		memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
167 		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
168 				     sb->s_blocksize * 8, bh->b_data);
169 		set_bitmap_uptodate(bh);
170 		set_buffer_uptodate(bh);
171 		set_buffer_verified(bh);
172 		ext4_unlock_group(sb, block_group);
173 		unlock_buffer(bh);
174 		return bh;
175 	}
176 	ext4_unlock_group(sb, block_group);
177 
178 	if (buffer_uptodate(bh)) {
179 		/*
180 		 * if not uninit if bh is uptodate,
181 		 * bitmap is also uptodate
182 		 */
183 		set_bitmap_uptodate(bh);
184 		unlock_buffer(bh);
185 		goto verify;
186 	}
187 	/*
188 	 * submit the buffer_head for reading
189 	 */
190 	trace_ext4_load_inode_bitmap(sb, block_group);
191 	bh->b_end_io = ext4_end_bitmap_read;
192 	get_bh(bh);
193 	submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
194 	wait_on_buffer(bh);
195 	if (!buffer_uptodate(bh)) {
196 		put_bh(bh);
197 		ext4_error(sb, "Cannot read inode bitmap - "
198 			   "block_group = %u, inode_bitmap = %llu",
199 			   block_group, bitmap_blk);
200 		ext4_mark_group_bitmap_corrupted(sb, block_group,
201 				EXT4_GROUP_INFO_IBITMAP_CORRUPT);
202 		return ERR_PTR(-EIO);
203 	}
204 
205 verify:
206 	err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
207 	if (err)
208 		goto out;
209 	return bh;
210 out:
211 	put_bh(bh);
212 	return ERR_PTR(err);
213 }
214 
215 /*
216  * NOTE! When we get the inode, we're the only people
217  * that have access to it, and as such there are no
218  * race conditions we have to worry about. The inode
219  * is not on the hash-lists, and it cannot be reached
220  * through the filesystem because the directory entry
221  * has been deleted earlier.
222  *
223  * HOWEVER: we must make sure that we get no aliases,
224  * which means that we have to call "clear_inode()"
225  * _before_ we mark the inode not in use in the inode
226  * bitmaps. Otherwise a newly created file might use
227  * the same inode number (not actually the same pointer
228  * though), and then we'd have two inodes sharing the
229  * same inode number and space on the harddisk.
230  */
ext4_free_inode(handle_t * handle,struct inode * inode)231 void ext4_free_inode(handle_t *handle, struct inode *inode)
232 {
233 	struct super_block *sb = inode->i_sb;
234 	int is_directory;
235 	unsigned long ino;
236 	struct buffer_head *bitmap_bh = NULL;
237 	struct buffer_head *bh2;
238 	ext4_group_t block_group;
239 	unsigned long bit;
240 	struct ext4_group_desc *gdp;
241 	struct ext4_super_block *es;
242 	struct ext4_sb_info *sbi;
243 	int fatal = 0, err, count, cleared;
244 	struct ext4_group_info *grp;
245 
246 	if (!sb) {
247 		printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
248 		       "nonexistent device\n", __func__, __LINE__);
249 		return;
250 	}
251 	if (atomic_read(&inode->i_count) > 1) {
252 		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
253 			 __func__, __LINE__, inode->i_ino,
254 			 atomic_read(&inode->i_count));
255 		return;
256 	}
257 	if (inode->i_nlink) {
258 		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
259 			 __func__, __LINE__, inode->i_ino, inode->i_nlink);
260 		return;
261 	}
262 	sbi = EXT4_SB(sb);
263 
264 	ino = inode->i_ino;
265 	ext4_debug("freeing inode %lu\n", ino);
266 	trace_ext4_free_inode(inode);
267 
268 	/*
269 	 * Note: we must free any quota before locking the superblock,
270 	 * as writing the quota to disk may need the lock as well.
271 	 */
272 	dquot_initialize(inode);
273 	dquot_free_inode(inode);
274 	dquot_drop(inode);
275 
276 	is_directory = S_ISDIR(inode->i_mode);
277 
278 	/* Do this BEFORE marking the inode not in use or returning an error */
279 	ext4_clear_inode(inode);
280 
281 	es = sbi->s_es;
282 	if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
283 		ext4_error(sb, "reserved or nonexistent inode %lu", ino);
284 		goto error_return;
285 	}
286 	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
287 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
288 	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
289 	/* Don't bother if the inode bitmap is corrupt. */
290 	grp = ext4_get_group_info(sb, block_group);
291 	if (IS_ERR(bitmap_bh)) {
292 		fatal = PTR_ERR(bitmap_bh);
293 		bitmap_bh = NULL;
294 		goto error_return;
295 	}
296 	if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
297 		fatal = -EFSCORRUPTED;
298 		goto error_return;
299 	}
300 
301 	BUFFER_TRACE(bitmap_bh, "get_write_access");
302 	fatal = ext4_journal_get_write_access(handle, bitmap_bh);
303 	if (fatal)
304 		goto error_return;
305 
306 	fatal = -ESRCH;
307 	gdp = ext4_get_group_desc(sb, block_group, &bh2);
308 	if (gdp) {
309 		BUFFER_TRACE(bh2, "get_write_access");
310 		fatal = ext4_journal_get_write_access(handle, bh2);
311 	}
312 	ext4_lock_group(sb, block_group);
313 	cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
314 	if (fatal || !cleared) {
315 		ext4_unlock_group(sb, block_group);
316 		goto out;
317 	}
318 
319 	count = ext4_free_inodes_count(sb, gdp) + 1;
320 	ext4_free_inodes_set(sb, gdp, count);
321 	if (is_directory) {
322 		count = ext4_used_dirs_count(sb, gdp) - 1;
323 		ext4_used_dirs_set(sb, gdp, count);
324 		percpu_counter_dec(&sbi->s_dirs_counter);
325 	}
326 	ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
327 				   EXT4_INODES_PER_GROUP(sb) / 8);
328 	ext4_group_desc_csum_set(sb, block_group, gdp);
329 	ext4_unlock_group(sb, block_group);
330 
331 	percpu_counter_inc(&sbi->s_freeinodes_counter);
332 	if (sbi->s_log_groups_per_flex) {
333 		struct flex_groups *fg;
334 
335 		fg = sbi_array_rcu_deref(sbi, s_flex_groups,
336 					 ext4_flex_group(sbi, block_group));
337 		atomic_inc(&fg->free_inodes);
338 		if (is_directory)
339 			atomic_dec(&fg->used_dirs);
340 	}
341 	BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
342 	fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
343 out:
344 	if (cleared) {
345 		BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
346 		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
347 		if (!fatal)
348 			fatal = err;
349 	} else {
350 		ext4_error(sb, "bit already cleared for inode %lu", ino);
351 		ext4_mark_group_bitmap_corrupted(sb, block_group,
352 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
353 	}
354 
355 error_return:
356 	brelse(bitmap_bh);
357 	ext4_std_error(sb, fatal);
358 }
359 
360 struct orlov_stats {
361 	__u64 free_clusters;
362 	__u32 free_inodes;
363 	__u32 used_dirs;
364 };
365 
366 /*
367  * Helper function for Orlov's allocator; returns critical information
368  * for a particular block group or flex_bg.  If flex_size is 1, then g
369  * is a block group number; otherwise it is flex_bg number.
370  */
get_orlov_stats(struct super_block * sb,ext4_group_t g,int flex_size,struct orlov_stats * stats)371 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
372 			    int flex_size, struct orlov_stats *stats)
373 {
374 	struct ext4_group_desc *desc;
375 
376 	if (flex_size > 1) {
377 		struct flex_groups *fg = sbi_array_rcu_deref(EXT4_SB(sb),
378 							     s_flex_groups, g);
379 		stats->free_inodes = atomic_read(&fg->free_inodes);
380 		stats->free_clusters = atomic64_read(&fg->free_clusters);
381 		stats->used_dirs = atomic_read(&fg->used_dirs);
382 		return;
383 	}
384 
385 	desc = ext4_get_group_desc(sb, g, NULL);
386 	if (desc) {
387 		stats->free_inodes = ext4_free_inodes_count(sb, desc);
388 		stats->free_clusters = ext4_free_group_clusters(sb, desc);
389 		stats->used_dirs = ext4_used_dirs_count(sb, desc);
390 	} else {
391 		stats->free_inodes = 0;
392 		stats->free_clusters = 0;
393 		stats->used_dirs = 0;
394 	}
395 }
396 
397 /*
398  * Orlov's allocator for directories.
399  *
400  * We always try to spread first-level directories.
401  *
402  * If there are blockgroups with both free inodes and free clusters counts
403  * not worse than average we return one with smallest directory count.
404  * Otherwise we simply return a random group.
405  *
406  * For the rest rules look so:
407  *
408  * It's OK to put directory into a group unless
409  * it has too many directories already (max_dirs) or
410  * it has too few free inodes left (min_inodes) or
411  * it has too few free clusters left (min_clusters) or
412  * Parent's group is preferred, if it doesn't satisfy these
413  * conditions we search cyclically through the rest. If none
414  * of the groups look good we just look for a group with more
415  * free inodes than average (starting at parent's group).
416  */
417 
find_group_orlov(struct super_block * sb,struct inode * parent,ext4_group_t * group,umode_t mode,const struct qstr * qstr)418 static int find_group_orlov(struct super_block *sb, struct inode *parent,
419 			    ext4_group_t *group, umode_t mode,
420 			    const struct qstr *qstr)
421 {
422 	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
423 	struct ext4_sb_info *sbi = EXT4_SB(sb);
424 	ext4_group_t real_ngroups = ext4_get_groups_count(sb);
425 	int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
426 	unsigned int freei, avefreei, grp_free;
427 	ext4_fsblk_t freec, avefreec;
428 	unsigned int ndirs;
429 	int max_dirs, min_inodes;
430 	ext4_grpblk_t min_clusters;
431 	ext4_group_t i, grp, g, ngroups;
432 	struct ext4_group_desc *desc;
433 	struct orlov_stats stats;
434 	int flex_size = ext4_flex_bg_size(sbi);
435 	struct dx_hash_info hinfo;
436 
437 	ngroups = real_ngroups;
438 	if (flex_size > 1) {
439 		ngroups = (real_ngroups + flex_size - 1) >>
440 			sbi->s_log_groups_per_flex;
441 		parent_group >>= sbi->s_log_groups_per_flex;
442 	}
443 
444 	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
445 	avefreei = freei / ngroups;
446 	freec = percpu_counter_read_positive(&sbi->s_freeclusters_counter);
447 	avefreec = freec;
448 	do_div(avefreec, ngroups);
449 	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
450 
451 	if (S_ISDIR(mode) &&
452 	    ((parent == d_inode(sb->s_root)) ||
453 	     (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
454 		int best_ndir = inodes_per_group;
455 		int ret = -1;
456 
457 		if (qstr) {
458 			hinfo.hash_version = DX_HASH_HALF_MD4;
459 			hinfo.seed = sbi->s_hash_seed;
460 			ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
461 			grp = hinfo.hash;
462 		} else
463 			grp = prandom_u32();
464 		parent_group = (unsigned)grp % ngroups;
465 		for (i = 0; i < ngroups; i++) {
466 			g = (parent_group + i) % ngroups;
467 			get_orlov_stats(sb, g, flex_size, &stats);
468 			if (!stats.free_inodes)
469 				continue;
470 			if (stats.used_dirs >= best_ndir)
471 				continue;
472 			if (stats.free_inodes < avefreei)
473 				continue;
474 			if (stats.free_clusters < avefreec)
475 				continue;
476 			grp = g;
477 			ret = 0;
478 			best_ndir = stats.used_dirs;
479 		}
480 		if (ret)
481 			goto fallback;
482 	found_flex_bg:
483 		if (flex_size == 1) {
484 			*group = grp;
485 			return 0;
486 		}
487 
488 		/*
489 		 * We pack inodes at the beginning of the flexgroup's
490 		 * inode tables.  Block allocation decisions will do
491 		 * something similar, although regular files will
492 		 * start at 2nd block group of the flexgroup.  See
493 		 * ext4_ext_find_goal() and ext4_find_near().
494 		 */
495 		grp *= flex_size;
496 		for (i = 0; i < flex_size; i++) {
497 			if (grp+i >= real_ngroups)
498 				break;
499 			desc = ext4_get_group_desc(sb, grp+i, NULL);
500 			if (desc && ext4_free_inodes_count(sb, desc)) {
501 				*group = grp+i;
502 				return 0;
503 			}
504 		}
505 		goto fallback;
506 	}
507 
508 	max_dirs = ndirs / ngroups + inodes_per_group*flex_size / 16;
509 	min_inodes = avefreei - inodes_per_group*flex_size / 4;
510 	if (min_inodes < 1)
511 		min_inodes = 1;
512 	min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
513 
514 	/*
515 	 * Start looking in the flex group where we last allocated an
516 	 * inode for this parent directory
517 	 */
518 	if (EXT4_I(parent)->i_last_alloc_group != ~0) {
519 		parent_group = EXT4_I(parent)->i_last_alloc_group;
520 		if (flex_size > 1)
521 			parent_group >>= sbi->s_log_groups_per_flex;
522 	}
523 
524 	for (i = 0; i < ngroups; i++) {
525 		grp = (parent_group + i) % ngroups;
526 		get_orlov_stats(sb, grp, flex_size, &stats);
527 		if (stats.used_dirs >= max_dirs)
528 			continue;
529 		if (stats.free_inodes < min_inodes)
530 			continue;
531 		if (stats.free_clusters < min_clusters)
532 			continue;
533 		goto found_flex_bg;
534 	}
535 
536 fallback:
537 	ngroups = real_ngroups;
538 	avefreei = freei / ngroups;
539 fallback_retry:
540 	parent_group = EXT4_I(parent)->i_block_group;
541 	for (i = 0; i < ngroups; i++) {
542 		grp = (parent_group + i) % ngroups;
543 		desc = ext4_get_group_desc(sb, grp, NULL);
544 		if (desc) {
545 			grp_free = ext4_free_inodes_count(sb, desc);
546 			if (grp_free && grp_free >= avefreei) {
547 				*group = grp;
548 				return 0;
549 			}
550 		}
551 	}
552 
553 	if (avefreei) {
554 		/*
555 		 * The free-inodes counter is approximate, and for really small
556 		 * filesystems the above test can fail to find any blockgroups
557 		 */
558 		avefreei = 0;
559 		goto fallback_retry;
560 	}
561 
562 	return -1;
563 }
564 
find_group_other(struct super_block * sb,struct inode * parent,ext4_group_t * group,umode_t mode)565 static int find_group_other(struct super_block *sb, struct inode *parent,
566 			    ext4_group_t *group, umode_t mode)
567 {
568 	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
569 	ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
570 	struct ext4_group_desc *desc;
571 	int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
572 
573 	/*
574 	 * Try to place the inode is the same flex group as its
575 	 * parent.  If we can't find space, use the Orlov algorithm to
576 	 * find another flex group, and store that information in the
577 	 * parent directory's inode information so that use that flex
578 	 * group for future allocations.
579 	 */
580 	if (flex_size > 1) {
581 		int retry = 0;
582 
583 	try_again:
584 		parent_group &= ~(flex_size-1);
585 		last = parent_group + flex_size;
586 		if (last > ngroups)
587 			last = ngroups;
588 		for  (i = parent_group; i < last; i++) {
589 			desc = ext4_get_group_desc(sb, i, NULL);
590 			if (desc && ext4_free_inodes_count(sb, desc)) {
591 				*group = i;
592 				return 0;
593 			}
594 		}
595 		if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
596 			retry = 1;
597 			parent_group = EXT4_I(parent)->i_last_alloc_group;
598 			goto try_again;
599 		}
600 		/*
601 		 * If this didn't work, use the Orlov search algorithm
602 		 * to find a new flex group; we pass in the mode to
603 		 * avoid the topdir algorithms.
604 		 */
605 		*group = parent_group + flex_size;
606 		if (*group > ngroups)
607 			*group = 0;
608 		return find_group_orlov(sb, parent, group, mode, NULL);
609 	}
610 
611 	/*
612 	 * Try to place the inode in its parent directory
613 	 */
614 	*group = parent_group;
615 	desc = ext4_get_group_desc(sb, *group, NULL);
616 	if (desc && ext4_free_inodes_count(sb, desc) &&
617 	    ext4_free_group_clusters(sb, desc))
618 		return 0;
619 
620 	/*
621 	 * We're going to place this inode in a different blockgroup from its
622 	 * parent.  We want to cause files in a common directory to all land in
623 	 * the same blockgroup.  But we want files which are in a different
624 	 * directory which shares a blockgroup with our parent to land in a
625 	 * different blockgroup.
626 	 *
627 	 * So add our directory's i_ino into the starting point for the hash.
628 	 */
629 	*group = (*group + parent->i_ino) % ngroups;
630 
631 	/*
632 	 * Use a quadratic hash to find a group with a free inode and some free
633 	 * blocks.
634 	 */
635 	for (i = 1; i < ngroups; i <<= 1) {
636 		*group += i;
637 		if (*group >= ngroups)
638 			*group -= ngroups;
639 		desc = ext4_get_group_desc(sb, *group, NULL);
640 		if (desc && ext4_free_inodes_count(sb, desc) &&
641 		    ext4_free_group_clusters(sb, desc))
642 			return 0;
643 	}
644 
645 	/*
646 	 * That failed: try linear search for a free inode, even if that group
647 	 * has no free blocks.
648 	 */
649 	*group = parent_group;
650 	for (i = 0; i < ngroups; i++) {
651 		if (++*group >= ngroups)
652 			*group = 0;
653 		desc = ext4_get_group_desc(sb, *group, NULL);
654 		if (desc && ext4_free_inodes_count(sb, desc))
655 			return 0;
656 	}
657 
658 	return -1;
659 }
660 
661 /*
662  * In no journal mode, if an inode has recently been deleted, we want
663  * to avoid reusing it until we're reasonably sure the inode table
664  * block has been written back to disk.  (Yes, these values are
665  * somewhat arbitrary...)
666  */
667 #define RECENTCY_MIN	60
668 #define RECENTCY_DIRTY	300
669 
recently_deleted(struct super_block * sb,ext4_group_t group,int ino)670 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
671 {
672 	struct ext4_group_desc	*gdp;
673 	struct ext4_inode	*raw_inode;
674 	struct buffer_head	*bh;
675 	int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
676 	int offset, ret = 0;
677 	int recentcy = RECENTCY_MIN;
678 	u32 dtime, now;
679 
680 	gdp = ext4_get_group_desc(sb, group, NULL);
681 	if (unlikely(!gdp))
682 		return 0;
683 
684 	bh = sb_find_get_block(sb, ext4_inode_table(sb, gdp) +
685 		       (ino / inodes_per_block));
686 	if (!bh || !buffer_uptodate(bh))
687 		/*
688 		 * If the block is not in the buffer cache, then it
689 		 * must have been written out.
690 		 */
691 		goto out;
692 
693 	offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
694 	raw_inode = (struct ext4_inode *) (bh->b_data + offset);
695 
696 	/* i_dtime is only 32 bits on disk, but we only care about relative
697 	 * times in the range of a few minutes (i.e. long enough to sync a
698 	 * recently-deleted inode to disk), so using the low 32 bits of the
699 	 * clock (a 68 year range) is enough, see time_before32() */
700 	dtime = le32_to_cpu(raw_inode->i_dtime);
701 	now = ktime_get_real_seconds();
702 	if (buffer_dirty(bh))
703 		recentcy += RECENTCY_DIRTY;
704 
705 	if (dtime && time_before32(dtime, now) &&
706 	    time_before32(now, dtime + recentcy))
707 		ret = 1;
708 out:
709 	brelse(bh);
710 	return ret;
711 }
712 
find_inode_bit(struct super_block * sb,ext4_group_t group,struct buffer_head * bitmap,unsigned long * ino)713 static int find_inode_bit(struct super_block *sb, ext4_group_t group,
714 			  struct buffer_head *bitmap, unsigned long *ino)
715 {
716 next:
717 	*ino = ext4_find_next_zero_bit((unsigned long *)
718 				       bitmap->b_data,
719 				       EXT4_INODES_PER_GROUP(sb), *ino);
720 	if (*ino >= EXT4_INODES_PER_GROUP(sb))
721 		return 0;
722 
723 	if ((EXT4_SB(sb)->s_journal == NULL) &&
724 	    recently_deleted(sb, group, *ino)) {
725 		*ino = *ino + 1;
726 		if (*ino < EXT4_INODES_PER_GROUP(sb))
727 			goto next;
728 		return 0;
729 	}
730 
731 	return 1;
732 }
733 
734 /*
735  * There are two policies for allocating an inode.  If the new inode is
736  * a directory, then a forward search is made for a block group with both
737  * free space and a low directory-to-inode ratio; if that fails, then of
738  * the groups with above-average free space, that group with the fewest
739  * directories already is chosen.
740  *
741  * For other inodes, search forward from the parent directory's block
742  * group to find a free inode.
743  */
__ext4_new_inode(handle_t * handle,struct inode * dir,umode_t mode,const struct qstr * qstr,__u32 goal,uid_t * owner,__u32 i_flags,int handle_type,unsigned int line_no,int nblocks)744 struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
745 			       umode_t mode, const struct qstr *qstr,
746 			       __u32 goal, uid_t *owner, __u32 i_flags,
747 			       int handle_type, unsigned int line_no,
748 			       int nblocks)
749 {
750 	struct super_block *sb;
751 	struct buffer_head *inode_bitmap_bh = NULL;
752 	struct buffer_head *group_desc_bh;
753 	ext4_group_t ngroups, group = 0;
754 	unsigned long ino = 0;
755 	struct inode *inode;
756 	struct ext4_group_desc *gdp = NULL;
757 	struct ext4_inode_info *ei;
758 	struct ext4_sb_info *sbi;
759 	int ret2, err;
760 	struct inode *ret;
761 	ext4_group_t i;
762 	ext4_group_t flex_group;
763 	struct ext4_group_info *grp;
764 	int encrypt = 0;
765 
766 	/* Cannot create files in a deleted directory */
767 	if (!dir || !dir->i_nlink)
768 		return ERR_PTR(-EPERM);
769 
770 	sb = dir->i_sb;
771 	sbi = EXT4_SB(sb);
772 
773 	if (unlikely(ext4_forced_shutdown(sbi)))
774 		return ERR_PTR(-EIO);
775 
776 	if ((ext4_encrypted_inode(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) &&
777 	    (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) &&
778 	    !(i_flags & EXT4_EA_INODE_FL)) {
779 		err = fscrypt_get_encryption_info(dir);
780 		if (err)
781 			return ERR_PTR(err);
782 		if (!fscrypt_has_encryption_key(dir))
783 			return ERR_PTR(-ENOKEY);
784 		encrypt = 1;
785 	}
786 
787 	if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
788 #ifdef CONFIG_EXT4_FS_POSIX_ACL
789 		struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
790 
791 		if (IS_ERR(p))
792 			return ERR_CAST(p);
793 		if (p) {
794 			int acl_size = p->a_count * sizeof(ext4_acl_entry);
795 
796 			nblocks += (S_ISDIR(mode) ? 2 : 1) *
797 				__ext4_xattr_set_credits(sb, NULL /* inode */,
798 					NULL /* block_bh */, acl_size,
799 					true /* is_create */);
800 			posix_acl_release(p);
801 		}
802 #endif
803 
804 #ifdef CONFIG_SECURITY
805 		{
806 			int num_security_xattrs = 1;
807 
808 #ifdef CONFIG_INTEGRITY
809 			num_security_xattrs++;
810 #endif
811 			/*
812 			 * We assume that security xattrs are never
813 			 * more than 1k.  In practice they are under
814 			 * 128 bytes.
815 			 */
816 			nblocks += num_security_xattrs *
817 				__ext4_xattr_set_credits(sb, NULL /* inode */,
818 					NULL /* block_bh */, 1024,
819 					true /* is_create */);
820 		}
821 #endif
822 		if (encrypt)
823 			nblocks += __ext4_xattr_set_credits(sb,
824 					NULL /* inode */, NULL /* block_bh */,
825 					FSCRYPT_SET_CONTEXT_MAX_SIZE,
826 					true /* is_create */);
827 	}
828 
829 	ngroups = ext4_get_groups_count(sb);
830 	trace_ext4_request_inode(dir, mode);
831 	inode = new_inode(sb);
832 	if (!inode)
833 		return ERR_PTR(-ENOMEM);
834 	ei = EXT4_I(inode);
835 
836 	/*
837 	 * Initialize owners and quota early so that we don't have to account
838 	 * for quota initialization worst case in standard inode creating
839 	 * transaction
840 	 */
841 	if (owner) {
842 		inode->i_mode = mode;
843 		i_uid_write(inode, owner[0]);
844 		i_gid_write(inode, owner[1]);
845 	} else if (test_opt(sb, GRPID)) {
846 		inode->i_mode = mode;
847 		inode->i_uid = current_fsuid();
848 		inode->i_gid = dir->i_gid;
849 	} else
850 		inode_init_owner(inode, dir, mode);
851 
852 	if (ext4_has_feature_project(sb) &&
853 	    ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
854 		ei->i_projid = EXT4_I(dir)->i_projid;
855 	else
856 		ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
857 
858 	err = dquot_initialize(inode);
859 	if (err)
860 		goto out;
861 
862 	if (!goal)
863 		goal = sbi->s_inode_goal;
864 
865 	if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
866 		group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
867 		ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
868 		ret2 = 0;
869 		goto got_group;
870 	}
871 
872 	if (S_ISDIR(mode))
873 		ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
874 	else
875 		ret2 = find_group_other(sb, dir, &group, mode);
876 
877 got_group:
878 	EXT4_I(dir)->i_last_alloc_group = group;
879 	err = -ENOSPC;
880 	if (ret2 == -1)
881 		goto out;
882 
883 	/*
884 	 * Normally we will only go through one pass of this loop,
885 	 * unless we get unlucky and it turns out the group we selected
886 	 * had its last inode grabbed by someone else.
887 	 */
888 	for (i = 0; i < ngroups; i++, ino = 0) {
889 		err = -EIO;
890 
891 		gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
892 		if (!gdp)
893 			goto out;
894 
895 		/*
896 		 * Check free inodes count before loading bitmap.
897 		 */
898 		if (ext4_free_inodes_count(sb, gdp) == 0)
899 			goto next_group;
900 
901 		grp = ext4_get_group_info(sb, group);
902 		/* Skip groups with already-known suspicious inode tables */
903 		if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
904 			goto next_group;
905 
906 		brelse(inode_bitmap_bh);
907 		inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
908 		/* Skip groups with suspicious inode tables */
909 		if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
910 		    IS_ERR(inode_bitmap_bh)) {
911 			inode_bitmap_bh = NULL;
912 			goto next_group;
913 		}
914 
915 repeat_in_this_group:
916 		ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
917 		if (!ret2)
918 			goto next_group;
919 
920 		if (group == 0 && (ino + 1) < EXT4_FIRST_INO(sb)) {
921 			ext4_error(sb, "reserved inode found cleared - "
922 				   "inode=%lu", ino + 1);
923 			ext4_mark_group_bitmap_corrupted(sb, group,
924 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
925 			goto next_group;
926 		}
927 
928 		if (!handle) {
929 			BUG_ON(nblocks <= 0);
930 			handle = __ext4_journal_start_sb(dir->i_sb, line_no,
931 							 handle_type, nblocks,
932 							 0);
933 			if (IS_ERR(handle)) {
934 				err = PTR_ERR(handle);
935 				ext4_std_error(sb, err);
936 				goto out;
937 			}
938 		}
939 		BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
940 		err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
941 		if (err) {
942 			ext4_std_error(sb, err);
943 			goto out;
944 		}
945 		ext4_lock_group(sb, group);
946 		ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
947 		if (ret2) {
948 			/* Someone already took the bit. Repeat the search
949 			 * with lock held.
950 			 */
951 			ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
952 			if (ret2) {
953 				ext4_set_bit(ino, inode_bitmap_bh->b_data);
954 				ret2 = 0;
955 			} else {
956 				ret2 = 1; /* we didn't grab the inode */
957 			}
958 		}
959 		ext4_unlock_group(sb, group);
960 		ino++;		/* the inode bitmap is zero-based */
961 		if (!ret2)
962 			goto got; /* we grabbed the inode! */
963 
964 		if (ino < EXT4_INODES_PER_GROUP(sb))
965 			goto repeat_in_this_group;
966 next_group:
967 		if (++group == ngroups)
968 			group = 0;
969 	}
970 	err = -ENOSPC;
971 	goto out;
972 
973 got:
974 	BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
975 	err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
976 	if (err) {
977 		ext4_std_error(sb, err);
978 		goto out;
979 	}
980 
981 	BUFFER_TRACE(group_desc_bh, "get_write_access");
982 	err = ext4_journal_get_write_access(handle, group_desc_bh);
983 	if (err) {
984 		ext4_std_error(sb, err);
985 		goto out;
986 	}
987 
988 	/* We may have to initialize the block bitmap if it isn't already */
989 	if (ext4_has_group_desc_csum(sb) &&
990 	    gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
991 		struct buffer_head *block_bitmap_bh;
992 
993 		block_bitmap_bh = ext4_read_block_bitmap(sb, group);
994 		if (IS_ERR(block_bitmap_bh)) {
995 			err = PTR_ERR(block_bitmap_bh);
996 			goto out;
997 		}
998 		BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
999 		err = ext4_journal_get_write_access(handle, block_bitmap_bh);
1000 		if (err) {
1001 			brelse(block_bitmap_bh);
1002 			ext4_std_error(sb, err);
1003 			goto out;
1004 		}
1005 
1006 		BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
1007 		err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
1008 
1009 		/* recheck and clear flag under lock if we still need to */
1010 		ext4_lock_group(sb, group);
1011 		if (ext4_has_group_desc_csum(sb) &&
1012 		    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
1013 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
1014 			ext4_free_group_clusters_set(sb, gdp,
1015 				ext4_free_clusters_after_init(sb, group, gdp));
1016 			ext4_block_bitmap_csum_set(sb, group, gdp,
1017 						   block_bitmap_bh);
1018 			ext4_group_desc_csum_set(sb, group, gdp);
1019 		}
1020 		ext4_unlock_group(sb, group);
1021 		brelse(block_bitmap_bh);
1022 
1023 		if (err) {
1024 			ext4_std_error(sb, err);
1025 			goto out;
1026 		}
1027 	}
1028 
1029 	/* Update the relevant bg descriptor fields */
1030 	if (ext4_has_group_desc_csum(sb)) {
1031 		int free;
1032 		struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1033 
1034 		down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
1035 		ext4_lock_group(sb, group); /* while we modify the bg desc */
1036 		free = EXT4_INODES_PER_GROUP(sb) -
1037 			ext4_itable_unused_count(sb, gdp);
1038 		if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
1039 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
1040 			free = 0;
1041 		}
1042 		/*
1043 		 * Check the relative inode number against the last used
1044 		 * relative inode number in this group. if it is greater
1045 		 * we need to update the bg_itable_unused count
1046 		 */
1047 		if (ino > free)
1048 			ext4_itable_unused_set(sb, gdp,
1049 					(EXT4_INODES_PER_GROUP(sb) - ino));
1050 		up_read(&grp->alloc_sem);
1051 	} else {
1052 		ext4_lock_group(sb, group);
1053 	}
1054 
1055 	ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1056 	if (S_ISDIR(mode)) {
1057 		ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1058 		if (sbi->s_log_groups_per_flex) {
1059 			ext4_group_t f = ext4_flex_group(sbi, group);
1060 
1061 			atomic_inc(&sbi_array_rcu_deref(sbi, s_flex_groups,
1062 							f)->used_dirs);
1063 		}
1064 	}
1065 	if (ext4_has_group_desc_csum(sb)) {
1066 		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1067 					   EXT4_INODES_PER_GROUP(sb) / 8);
1068 		ext4_group_desc_csum_set(sb, group, gdp);
1069 	}
1070 	ext4_unlock_group(sb, group);
1071 
1072 	BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1073 	err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1074 	if (err) {
1075 		ext4_std_error(sb, err);
1076 		goto out;
1077 	}
1078 
1079 	percpu_counter_dec(&sbi->s_freeinodes_counter);
1080 	if (S_ISDIR(mode))
1081 		percpu_counter_inc(&sbi->s_dirs_counter);
1082 
1083 	if (sbi->s_log_groups_per_flex) {
1084 		flex_group = ext4_flex_group(sbi, group);
1085 		atomic_dec(&sbi_array_rcu_deref(sbi, s_flex_groups,
1086 						flex_group)->free_inodes);
1087 	}
1088 
1089 	inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1090 	/* This is the optimal IO size (for stat), not the fs block size */
1091 	inode->i_blocks = 0;
1092 	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1093 	ei->i_crtime = inode->i_mtime;
1094 
1095 	memset(ei->i_data, 0, sizeof(ei->i_data));
1096 	ei->i_dir_start_lookup = 0;
1097 	ei->i_disksize = 0;
1098 
1099 	/* Don't inherit extent flag from directory, amongst others. */
1100 	ei->i_flags =
1101 		ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1102 	ei->i_flags |= i_flags;
1103 	ei->i_file_acl = 0;
1104 	ei->i_dtime = 0;
1105 	ei->i_block_group = group;
1106 	ei->i_last_alloc_group = ~0;
1107 
1108 	ext4_set_inode_flags(inode);
1109 	if (IS_DIRSYNC(inode))
1110 		ext4_handle_sync(handle);
1111 	if (insert_inode_locked(inode) < 0) {
1112 		/*
1113 		 * Likely a bitmap corruption causing inode to be allocated
1114 		 * twice.
1115 		 */
1116 		err = -EIO;
1117 		ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1118 			   inode->i_ino);
1119 		ext4_mark_group_bitmap_corrupted(sb, group,
1120 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
1121 		goto out;
1122 	}
1123 	inode->i_generation = prandom_u32();
1124 
1125 	/* Precompute checksum seed for inode metadata */
1126 	if (ext4_has_metadata_csum(sb)) {
1127 		__u32 csum;
1128 		__le32 inum = cpu_to_le32(inode->i_ino);
1129 		__le32 gen = cpu_to_le32(inode->i_generation);
1130 		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1131 				   sizeof(inum));
1132 		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1133 					      sizeof(gen));
1134 	}
1135 
1136 	ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1137 	ext4_set_inode_state(inode, EXT4_STATE_NEW);
1138 
1139 	ei->i_extra_isize = sbi->s_want_extra_isize;
1140 	ei->i_inline_off = 0;
1141 	if (ext4_has_feature_inline_data(sb))
1142 		ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1143 	ret = inode;
1144 	err = dquot_alloc_inode(inode);
1145 	if (err)
1146 		goto fail_drop;
1147 
1148 	/*
1149 	 * Since the encryption xattr will always be unique, create it first so
1150 	 * that it's less likely to end up in an external xattr block and
1151 	 * prevent its deduplication.
1152 	 */
1153 	if (encrypt) {
1154 		err = fscrypt_inherit_context(dir, inode, handle, true);
1155 		if (err)
1156 			goto fail_free_drop;
1157 	}
1158 
1159 	if (!(ei->i_flags & EXT4_EA_INODE_FL)) {
1160 		err = ext4_init_acl(handle, inode, dir);
1161 		if (err)
1162 			goto fail_free_drop;
1163 
1164 		err = ext4_init_security(handle, inode, dir, qstr);
1165 		if (err)
1166 			goto fail_free_drop;
1167 	}
1168 
1169 	if (ext4_has_feature_extents(sb)) {
1170 		/* set extent flag only for directory, file and normal symlink*/
1171 		if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1172 			ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1173 			ext4_ext_tree_init(handle, inode);
1174 		}
1175 	}
1176 
1177 	if (ext4_handle_valid(handle)) {
1178 		ei->i_sync_tid = handle->h_transaction->t_tid;
1179 		ei->i_datasync_tid = handle->h_transaction->t_tid;
1180 	}
1181 
1182 	err = ext4_mark_inode_dirty(handle, inode);
1183 	if (err) {
1184 		ext4_std_error(sb, err);
1185 		goto fail_free_drop;
1186 	}
1187 
1188 	ext4_debug("allocating inode %lu\n", inode->i_ino);
1189 	trace_ext4_allocate_inode(inode, dir, mode);
1190 	brelse(inode_bitmap_bh);
1191 	return ret;
1192 
1193 fail_free_drop:
1194 	dquot_free_inode(inode);
1195 fail_drop:
1196 	clear_nlink(inode);
1197 	unlock_new_inode(inode);
1198 out:
1199 	dquot_drop(inode);
1200 	inode->i_flags |= S_NOQUOTA;
1201 	iput(inode);
1202 	brelse(inode_bitmap_bh);
1203 	return ERR_PTR(err);
1204 }
1205 
1206 /* Verify that we are loading a valid orphan from disk */
ext4_orphan_get(struct super_block * sb,unsigned long ino)1207 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1208 {
1209 	unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1210 	ext4_group_t block_group;
1211 	int bit;
1212 	struct buffer_head *bitmap_bh = NULL;
1213 	struct inode *inode = NULL;
1214 	int err = -EFSCORRUPTED;
1215 
1216 	if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
1217 		goto bad_orphan;
1218 
1219 	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1220 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1221 	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1222 	if (IS_ERR(bitmap_bh))
1223 		return (struct inode *) bitmap_bh;
1224 
1225 	/* Having the inode bit set should be a 100% indicator that this
1226 	 * is a valid orphan (no e2fsck run on fs).  Orphans also include
1227 	 * inodes that were being truncated, so we can't check i_nlink==0.
1228 	 */
1229 	if (!ext4_test_bit(bit, bitmap_bh->b_data))
1230 		goto bad_orphan;
1231 
1232 	inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
1233 	if (IS_ERR(inode)) {
1234 		err = PTR_ERR(inode);
1235 		ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
1236 			   ino, err);
1237 		return inode;
1238 	}
1239 
1240 	/*
1241 	 * If the orphans has i_nlinks > 0 then it should be able to
1242 	 * be truncated, otherwise it won't be removed from the orphan
1243 	 * list during processing and an infinite loop will result.
1244 	 * Similarly, it must not be a bad inode.
1245 	 */
1246 	if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
1247 	    is_bad_inode(inode))
1248 		goto bad_orphan;
1249 
1250 	if (NEXT_ORPHAN(inode) > max_ino)
1251 		goto bad_orphan;
1252 	brelse(bitmap_bh);
1253 	return inode;
1254 
1255 bad_orphan:
1256 	ext4_error(sb, "bad orphan inode %lu", ino);
1257 	if (bitmap_bh)
1258 		printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1259 		       bit, (unsigned long long)bitmap_bh->b_blocknr,
1260 		       ext4_test_bit(bit, bitmap_bh->b_data));
1261 	if (inode) {
1262 		printk(KERN_ERR "is_bad_inode(inode)=%d\n",
1263 		       is_bad_inode(inode));
1264 		printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
1265 		       NEXT_ORPHAN(inode));
1266 		printk(KERN_ERR "max_ino=%lu\n", max_ino);
1267 		printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
1268 		/* Avoid freeing blocks if we got a bad deleted inode */
1269 		if (inode->i_nlink == 0)
1270 			inode->i_blocks = 0;
1271 		iput(inode);
1272 	}
1273 	brelse(bitmap_bh);
1274 	return ERR_PTR(err);
1275 }
1276 
ext4_count_free_inodes(struct super_block * sb)1277 unsigned long ext4_count_free_inodes(struct super_block *sb)
1278 {
1279 	unsigned long desc_count;
1280 	struct ext4_group_desc *gdp;
1281 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1282 #ifdef EXT4FS_DEBUG
1283 	struct ext4_super_block *es;
1284 	unsigned long bitmap_count, x;
1285 	struct buffer_head *bitmap_bh = NULL;
1286 
1287 	es = EXT4_SB(sb)->s_es;
1288 	desc_count = 0;
1289 	bitmap_count = 0;
1290 	gdp = NULL;
1291 	for (i = 0; i < ngroups; i++) {
1292 		gdp = ext4_get_group_desc(sb, i, NULL);
1293 		if (!gdp)
1294 			continue;
1295 		desc_count += ext4_free_inodes_count(sb, gdp);
1296 		brelse(bitmap_bh);
1297 		bitmap_bh = ext4_read_inode_bitmap(sb, i);
1298 		if (IS_ERR(bitmap_bh)) {
1299 			bitmap_bh = NULL;
1300 			continue;
1301 		}
1302 
1303 		x = ext4_count_free(bitmap_bh->b_data,
1304 				    EXT4_INODES_PER_GROUP(sb) / 8);
1305 		printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1306 			(unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1307 		bitmap_count += x;
1308 	}
1309 	brelse(bitmap_bh);
1310 	printk(KERN_DEBUG "ext4_count_free_inodes: "
1311 	       "stored = %u, computed = %lu, %lu\n",
1312 	       le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1313 	return desc_count;
1314 #else
1315 	desc_count = 0;
1316 	for (i = 0; i < ngroups; i++) {
1317 		gdp = ext4_get_group_desc(sb, i, NULL);
1318 		if (!gdp)
1319 			continue;
1320 		desc_count += ext4_free_inodes_count(sb, gdp);
1321 		cond_resched();
1322 	}
1323 	return desc_count;
1324 #endif
1325 }
1326 
1327 /* Called at mount-time, super-block is locked */
ext4_count_dirs(struct super_block * sb)1328 unsigned long ext4_count_dirs(struct super_block * sb)
1329 {
1330 	unsigned long count = 0;
1331 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1332 
1333 	for (i = 0; i < ngroups; i++) {
1334 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1335 		if (!gdp)
1336 			continue;
1337 		count += ext4_used_dirs_count(sb, gdp);
1338 	}
1339 	return count;
1340 }
1341 
1342 /*
1343  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1344  * inode table. Must be called without any spinlock held. The only place
1345  * where it is called from on active part of filesystem is ext4lazyinit
1346  * thread, so we do not need any special locks, however we have to prevent
1347  * inode allocation from the current group, so we take alloc_sem lock, to
1348  * block ext4_new_inode() until we are finished.
1349  */
ext4_init_inode_table(struct super_block * sb,ext4_group_t group,int barrier)1350 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1351 				 int barrier)
1352 {
1353 	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1354 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1355 	struct ext4_group_desc *gdp = NULL;
1356 	struct buffer_head *group_desc_bh;
1357 	handle_t *handle;
1358 	ext4_fsblk_t blk;
1359 	int num, ret = 0, used_blks = 0;
1360 	unsigned long used_inos = 0;
1361 
1362 	/* This should not happen, but just to be sure check this */
1363 	if (sb_rdonly(sb)) {
1364 		ret = 1;
1365 		goto out;
1366 	}
1367 
1368 	gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1369 	if (!gdp)
1370 		goto out;
1371 
1372 	/*
1373 	 * We do not need to lock this, because we are the only one
1374 	 * handling this flag.
1375 	 */
1376 	if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1377 		goto out;
1378 
1379 	handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1380 	if (IS_ERR(handle)) {
1381 		ret = PTR_ERR(handle);
1382 		goto out;
1383 	}
1384 
1385 	down_write(&grp->alloc_sem);
1386 	/*
1387 	 * If inode bitmap was already initialized there may be some
1388 	 * used inodes so we need to skip blocks with used inodes in
1389 	 * inode table.
1390 	 */
1391 	if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
1392 		used_inos = EXT4_INODES_PER_GROUP(sb) -
1393 			    ext4_itable_unused_count(sb, gdp);
1394 		used_blks = DIV_ROUND_UP(used_inos, sbi->s_inodes_per_block);
1395 
1396 		/* Bogus inode unused count? */
1397 		if (used_blks < 0 || used_blks > sbi->s_itb_per_group) {
1398 			ext4_error(sb, "Something is wrong with group %u: "
1399 				   "used itable blocks: %d; "
1400 				   "itable unused count: %u",
1401 				   group, used_blks,
1402 				   ext4_itable_unused_count(sb, gdp));
1403 			ret = 1;
1404 			goto err_out;
1405 		}
1406 
1407 		used_inos += group * EXT4_INODES_PER_GROUP(sb);
1408 		/*
1409 		 * Are there some uninitialized inodes in the inode table
1410 		 * before the first normal inode?
1411 		 */
1412 		if ((used_blks != sbi->s_itb_per_group) &&
1413 		     (used_inos < EXT4_FIRST_INO(sb))) {
1414 			ext4_error(sb, "Something is wrong with group %u: "
1415 				   "itable unused count: %u; "
1416 				   "itables initialized count: %ld",
1417 				   group, ext4_itable_unused_count(sb, gdp),
1418 				   used_inos);
1419 			ret = 1;
1420 			goto err_out;
1421 		}
1422 	}
1423 
1424 	blk = ext4_inode_table(sb, gdp) + used_blks;
1425 	num = sbi->s_itb_per_group - used_blks;
1426 
1427 	BUFFER_TRACE(group_desc_bh, "get_write_access");
1428 	ret = ext4_journal_get_write_access(handle,
1429 					    group_desc_bh);
1430 	if (ret)
1431 		goto err_out;
1432 
1433 	/*
1434 	 * Skip zeroout if the inode table is full. But we set the ZEROED
1435 	 * flag anyway, because obviously, when it is full it does not need
1436 	 * further zeroing.
1437 	 */
1438 	if (unlikely(num == 0))
1439 		goto skip_zeroout;
1440 
1441 	ext4_debug("going to zero out inode table in group %d\n",
1442 		   group);
1443 	ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1444 	if (ret < 0)
1445 		goto err_out;
1446 	if (barrier)
1447 		blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1448 
1449 skip_zeroout:
1450 	ext4_lock_group(sb, group);
1451 	gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1452 	ext4_group_desc_csum_set(sb, group, gdp);
1453 	ext4_unlock_group(sb, group);
1454 
1455 	BUFFER_TRACE(group_desc_bh,
1456 		     "call ext4_handle_dirty_metadata");
1457 	ret = ext4_handle_dirty_metadata(handle, NULL,
1458 					 group_desc_bh);
1459 
1460 err_out:
1461 	up_write(&grp->alloc_sem);
1462 	ext4_journal_stop(handle);
1463 out:
1464 	return ret;
1465 }
1466