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;
86 
87 	if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
88 		return 0;
89 
90 	grp = ext4_get_group_info(sb, block_group);
91 
92 	if (buffer_verified(bh))
93 		return 0;
94 	if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
95 		return -EFSCORRUPTED;
96 
97 	ext4_lock_group(sb, block_group);
98 	if (buffer_verified(bh))
99 		goto verified;
100 	blk = ext4_inode_bitmap(sb, desc);
101 	if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
102 					   EXT4_INODES_PER_GROUP(sb) / 8) ||
103 	    ext4_simulate_fail(sb, EXT4_SIM_IBITMAP_CRC)) {
104 		ext4_unlock_group(sb, block_group);
105 		ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
106 			   "inode_bitmap = %llu", block_group, blk);
107 		ext4_mark_group_bitmap_corrupted(sb, block_group,
108 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
109 		return -EFSBADCRC;
110 	}
111 	set_buffer_verified(bh);
112 verified:
113 	ext4_unlock_group(sb, block_group);
114 	return 0;
115 }
116 
117 /*
118  * Read the inode allocation bitmap for a given block_group, reading
119  * into the specified slot in the superblock's bitmap cache.
120  *
121  * Return buffer_head of bitmap on success, or an ERR_PTR on error.
122  */
123 static struct buffer_head *
ext4_read_inode_bitmap(struct super_block * sb,ext4_group_t block_group)124 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
125 {
126 	struct ext4_group_desc *desc;
127 	struct ext4_sb_info *sbi = EXT4_SB(sb);
128 	struct buffer_head *bh = NULL;
129 	ext4_fsblk_t bitmap_blk;
130 	int err;
131 
132 	desc = ext4_get_group_desc(sb, block_group, NULL);
133 	if (!desc)
134 		return ERR_PTR(-EFSCORRUPTED);
135 
136 	bitmap_blk = ext4_inode_bitmap(sb, desc);
137 	if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
138 	    (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
139 		ext4_error(sb, "Invalid inode bitmap blk %llu in "
140 			   "block_group %u", bitmap_blk, block_group);
141 		ext4_mark_group_bitmap_corrupted(sb, block_group,
142 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
143 		return ERR_PTR(-EFSCORRUPTED);
144 	}
145 	bh = sb_getblk(sb, bitmap_blk);
146 	if (unlikely(!bh)) {
147 		ext4_warning(sb, "Cannot read inode bitmap - "
148 			     "block_group = %u, inode_bitmap = %llu",
149 			     block_group, bitmap_blk);
150 		return ERR_PTR(-ENOMEM);
151 	}
152 	if (bitmap_uptodate(bh))
153 		goto verify;
154 
155 	lock_buffer(bh);
156 	if (bitmap_uptodate(bh)) {
157 		unlock_buffer(bh);
158 		goto verify;
159 	}
160 
161 	ext4_lock_group(sb, block_group);
162 	if (ext4_has_group_desc_csum(sb) &&
163 	    (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
164 		if (block_group == 0) {
165 			ext4_unlock_group(sb, block_group);
166 			unlock_buffer(bh);
167 			ext4_error(sb, "Inode bitmap for bg 0 marked "
168 				   "uninitialized");
169 			err = -EFSCORRUPTED;
170 			goto out;
171 		}
172 		memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
173 		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
174 				     sb->s_blocksize * 8, bh->b_data);
175 		set_bitmap_uptodate(bh);
176 		set_buffer_uptodate(bh);
177 		set_buffer_verified(bh);
178 		ext4_unlock_group(sb, block_group);
179 		unlock_buffer(bh);
180 		return bh;
181 	}
182 	ext4_unlock_group(sb, block_group);
183 
184 	if (buffer_uptodate(bh)) {
185 		/*
186 		 * if not uninit if bh is uptodate,
187 		 * bitmap is also uptodate
188 		 */
189 		set_bitmap_uptodate(bh);
190 		unlock_buffer(bh);
191 		goto verify;
192 	}
193 	/*
194 	 * submit the buffer_head for reading
195 	 */
196 	trace_ext4_load_inode_bitmap(sb, block_group);
197 	ext4_read_bh(bh, REQ_META | REQ_PRIO, ext4_end_bitmap_read);
198 	ext4_simulate_fail_bh(sb, bh, EXT4_SIM_IBITMAP_EIO);
199 	if (!buffer_uptodate(bh)) {
200 		put_bh(bh);
201 		ext4_error_err(sb, EIO, "Cannot read inode bitmap - "
202 			       "block_group = %u, inode_bitmap = %llu",
203 			       block_group, bitmap_blk);
204 		ext4_mark_group_bitmap_corrupted(sb, block_group,
205 				EXT4_GROUP_INFO_IBITMAP_CORRUPT);
206 		return ERR_PTR(-EIO);
207 	}
208 
209 verify:
210 	err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
211 	if (err)
212 		goto out;
213 	return bh;
214 out:
215 	put_bh(bh);
216 	return ERR_PTR(err);
217 }
218 
219 /*
220  * NOTE! When we get the inode, we're the only people
221  * that have access to it, and as such there are no
222  * race conditions we have to worry about. The inode
223  * is not on the hash-lists, and it cannot be reached
224  * through the filesystem because the directory entry
225  * has been deleted earlier.
226  *
227  * HOWEVER: we must make sure that we get no aliases,
228  * which means that we have to call "clear_inode()"
229  * _before_ we mark the inode not in use in the inode
230  * bitmaps. Otherwise a newly created file might use
231  * the same inode number (not actually the same pointer
232  * though), and then we'd have two inodes sharing the
233  * same inode number and space on the harddisk.
234  */
ext4_free_inode(handle_t * handle,struct inode * inode)235 void ext4_free_inode(handle_t *handle, struct inode *inode)
236 {
237 	struct super_block *sb = inode->i_sb;
238 	int is_directory;
239 	unsigned long ino;
240 	struct buffer_head *bitmap_bh = NULL;
241 	struct buffer_head *bh2;
242 	ext4_group_t block_group;
243 	unsigned long bit;
244 	struct ext4_group_desc *gdp;
245 	struct ext4_super_block *es;
246 	struct ext4_sb_info *sbi;
247 	int fatal = 0, err, count, cleared;
248 	struct ext4_group_info *grp;
249 
250 	if (!sb) {
251 		printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
252 		       "nonexistent device\n", __func__, __LINE__);
253 		return;
254 	}
255 	if (atomic_read(&inode->i_count) > 1) {
256 		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
257 			 __func__, __LINE__, inode->i_ino,
258 			 atomic_read(&inode->i_count));
259 		return;
260 	}
261 	if (inode->i_nlink) {
262 		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
263 			 __func__, __LINE__, inode->i_ino, inode->i_nlink);
264 		return;
265 	}
266 	sbi = EXT4_SB(sb);
267 
268 	ino = inode->i_ino;
269 	ext4_debug("freeing inode %lu\n", ino);
270 	trace_ext4_free_inode(inode);
271 
272 	dquot_initialize(inode);
273 	dquot_free_inode(inode);
274 
275 	is_directory = S_ISDIR(inode->i_mode);
276 
277 	/* Do this BEFORE marking the inode not in use or returning an error */
278 	ext4_clear_inode(inode);
279 
280 	es = sbi->s_es;
281 	if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
282 		ext4_error(sb, "reserved or nonexistent inode %lu", ino);
283 		goto error_return;
284 	}
285 	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
286 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
287 	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
288 	/* Don't bother if the inode bitmap is corrupt. */
289 	if (IS_ERR(bitmap_bh)) {
290 		fatal = PTR_ERR(bitmap_bh);
291 		bitmap_bh = NULL;
292 		goto error_return;
293 	}
294 	if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
295 		grp = ext4_get_group_info(sb, block_group);
296 		if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
297 			fatal = -EFSCORRUPTED;
298 			goto error_return;
299 		}
300 	}
301 
302 	BUFFER_TRACE(bitmap_bh, "get_write_access");
303 	fatal = ext4_journal_get_write_access(handle, sb, bitmap_bh,
304 					      EXT4_JTR_NONE);
305 	if (fatal)
306 		goto error_return;
307 
308 	fatal = -ESRCH;
309 	gdp = ext4_get_group_desc(sb, block_group, &bh2);
310 	if (gdp) {
311 		BUFFER_TRACE(bh2, "get_write_access");
312 		fatal = ext4_journal_get_write_access(handle, sb, bh2,
313 						      EXT4_JTR_NONE);
314 	}
315 	ext4_lock_group(sb, block_group);
316 	cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
317 	if (fatal || !cleared) {
318 		ext4_unlock_group(sb, block_group);
319 		goto out;
320 	}
321 
322 	count = ext4_free_inodes_count(sb, gdp) + 1;
323 	ext4_free_inodes_set(sb, gdp, count);
324 	if (is_directory) {
325 		count = ext4_used_dirs_count(sb, gdp) - 1;
326 		ext4_used_dirs_set(sb, gdp, count);
327 		if (percpu_counter_initialized(&sbi->s_dirs_counter))
328 			percpu_counter_dec(&sbi->s_dirs_counter);
329 	}
330 	ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
331 				   EXT4_INODES_PER_GROUP(sb) / 8);
332 	ext4_group_desc_csum_set(sb, block_group, gdp);
333 	ext4_unlock_group(sb, block_group);
334 
335 	if (percpu_counter_initialized(&sbi->s_freeinodes_counter))
336 		percpu_counter_inc(&sbi->s_freeinodes_counter);
337 	if (sbi->s_log_groups_per_flex) {
338 		struct flex_groups *fg;
339 
340 		fg = sbi_array_rcu_deref(sbi, s_flex_groups,
341 					 ext4_flex_group(sbi, block_group));
342 		atomic_inc(&fg->free_inodes);
343 		if (is_directory)
344 			atomic_dec(&fg->used_dirs);
345 	}
346 	BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
347 	fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
348 out:
349 	if (cleared) {
350 		BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
351 		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
352 		if (!fatal)
353 			fatal = err;
354 	} else {
355 		ext4_error(sb, "bit already cleared for inode %lu", ino);
356 		ext4_mark_group_bitmap_corrupted(sb, block_group,
357 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
358 	}
359 
360 error_return:
361 	brelse(bitmap_bh);
362 	ext4_std_error(sb, fatal);
363 }
364 
365 struct orlov_stats {
366 	__u64 free_clusters;
367 	__u32 free_inodes;
368 	__u32 used_dirs;
369 };
370 
371 /*
372  * Helper function for Orlov's allocator; returns critical information
373  * for a particular block group or flex_bg.  If flex_size is 1, then g
374  * is a block group number; otherwise it is flex_bg number.
375  */
get_orlov_stats(struct super_block * sb,ext4_group_t g,int flex_size,struct orlov_stats * stats)376 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
377 			    int flex_size, struct orlov_stats *stats)
378 {
379 	struct ext4_group_desc *desc;
380 
381 	if (flex_size > 1) {
382 		struct flex_groups *fg = sbi_array_rcu_deref(EXT4_SB(sb),
383 							     s_flex_groups, g);
384 		stats->free_inodes = atomic_read(&fg->free_inodes);
385 		stats->free_clusters = atomic64_read(&fg->free_clusters);
386 		stats->used_dirs = atomic_read(&fg->used_dirs);
387 		return;
388 	}
389 
390 	desc = ext4_get_group_desc(sb, g, NULL);
391 	if (desc) {
392 		stats->free_inodes = ext4_free_inodes_count(sb, desc);
393 		stats->free_clusters = ext4_free_group_clusters(sb, desc);
394 		stats->used_dirs = ext4_used_dirs_count(sb, desc);
395 	} else {
396 		stats->free_inodes = 0;
397 		stats->free_clusters = 0;
398 		stats->used_dirs = 0;
399 	}
400 }
401 
402 /*
403  * Orlov's allocator for directories.
404  *
405  * We always try to spread first-level directories.
406  *
407  * If there are blockgroups with both free inodes and free clusters counts
408  * not worse than average we return one with smallest directory count.
409  * Otherwise we simply return a random group.
410  *
411  * For the rest rules look so:
412  *
413  * It's OK to put directory into a group unless
414  * it has too many directories already (max_dirs) or
415  * it has too few free inodes left (min_inodes) or
416  * it has too few free clusters left (min_clusters) or
417  * Parent's group is preferred, if it doesn't satisfy these
418  * conditions we search cyclically through the rest. If none
419  * of the groups look good we just look for a group with more
420  * free inodes than average (starting at parent's group).
421  */
422 
find_group_orlov(struct super_block * sb,struct inode * parent,ext4_group_t * group,umode_t mode,const struct qstr * qstr)423 static int find_group_orlov(struct super_block *sb, struct inode *parent,
424 			    ext4_group_t *group, umode_t mode,
425 			    const struct qstr *qstr)
426 {
427 	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
428 	struct ext4_sb_info *sbi = EXT4_SB(sb);
429 	ext4_group_t real_ngroups = ext4_get_groups_count(sb);
430 	int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
431 	unsigned int freei, avefreei, grp_free;
432 	ext4_fsblk_t freec, avefreec;
433 	unsigned int ndirs;
434 	int max_dirs, min_inodes;
435 	ext4_grpblk_t min_clusters;
436 	ext4_group_t i, grp, g, ngroups;
437 	struct ext4_group_desc *desc;
438 	struct orlov_stats stats;
439 	int flex_size = ext4_flex_bg_size(sbi);
440 	struct dx_hash_info hinfo;
441 
442 	ngroups = real_ngroups;
443 	if (flex_size > 1) {
444 		ngroups = (real_ngroups + flex_size - 1) >>
445 			sbi->s_log_groups_per_flex;
446 		parent_group >>= sbi->s_log_groups_per_flex;
447 	}
448 
449 	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
450 	avefreei = freei / ngroups;
451 	freec = percpu_counter_read_positive(&sbi->s_freeclusters_counter);
452 	avefreec = freec;
453 	do_div(avefreec, ngroups);
454 	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
455 
456 	if (S_ISDIR(mode) &&
457 	    ((parent == d_inode(sb->s_root)) ||
458 	     (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
459 		int best_ndir = inodes_per_group;
460 		int ret = -1;
461 
462 		if (qstr) {
463 			hinfo.hash_version = DX_HASH_HALF_MD4;
464 			hinfo.seed = sbi->s_hash_seed;
465 			ext4fs_dirhash(parent, qstr->name, qstr->len, &hinfo);
466 			parent_group = hinfo.hash % ngroups;
467 		} else
468 			parent_group = prandom_u32_max(ngroups);
469 		for (i = 0; i < ngroups; i++) {
470 			g = (parent_group + i) % ngroups;
471 			get_orlov_stats(sb, g, flex_size, &stats);
472 			if (!stats.free_inodes)
473 				continue;
474 			if (stats.used_dirs >= best_ndir)
475 				continue;
476 			if (stats.free_inodes < avefreei)
477 				continue;
478 			if (stats.free_clusters < avefreec)
479 				continue;
480 			grp = g;
481 			ret = 0;
482 			best_ndir = stats.used_dirs;
483 		}
484 		if (ret)
485 			goto fallback;
486 	found_flex_bg:
487 		if (flex_size == 1) {
488 			*group = grp;
489 			return 0;
490 		}
491 
492 		/*
493 		 * We pack inodes at the beginning of the flexgroup's
494 		 * inode tables.  Block allocation decisions will do
495 		 * something similar, although regular files will
496 		 * start at 2nd block group of the flexgroup.  See
497 		 * ext4_ext_find_goal() and ext4_find_near().
498 		 */
499 		grp *= flex_size;
500 		for (i = 0; i < flex_size; i++) {
501 			if (grp+i >= real_ngroups)
502 				break;
503 			desc = ext4_get_group_desc(sb, grp+i, NULL);
504 			if (desc && ext4_free_inodes_count(sb, desc)) {
505 				*group = grp+i;
506 				return 0;
507 			}
508 		}
509 		goto fallback;
510 	}
511 
512 	max_dirs = ndirs / ngroups + inodes_per_group*flex_size / 16;
513 	min_inodes = avefreei - inodes_per_group*flex_size / 4;
514 	if (min_inodes < 1)
515 		min_inodes = 1;
516 	min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
517 
518 	/*
519 	 * Start looking in the flex group where we last allocated an
520 	 * inode for this parent directory
521 	 */
522 	if (EXT4_I(parent)->i_last_alloc_group != ~0) {
523 		parent_group = EXT4_I(parent)->i_last_alloc_group;
524 		if (flex_size > 1)
525 			parent_group >>= sbi->s_log_groups_per_flex;
526 	}
527 
528 	for (i = 0; i < ngroups; i++) {
529 		grp = (parent_group + i) % ngroups;
530 		get_orlov_stats(sb, grp, flex_size, &stats);
531 		if (stats.used_dirs >= max_dirs)
532 			continue;
533 		if (stats.free_inodes < min_inodes)
534 			continue;
535 		if (stats.free_clusters < min_clusters)
536 			continue;
537 		goto found_flex_bg;
538 	}
539 
540 fallback:
541 	ngroups = real_ngroups;
542 	avefreei = freei / ngroups;
543 fallback_retry:
544 	parent_group = EXT4_I(parent)->i_block_group;
545 	for (i = 0; i < ngroups; i++) {
546 		grp = (parent_group + i) % ngroups;
547 		desc = ext4_get_group_desc(sb, grp, NULL);
548 		if (desc) {
549 			grp_free = ext4_free_inodes_count(sb, desc);
550 			if (grp_free && grp_free >= avefreei) {
551 				*group = grp;
552 				return 0;
553 			}
554 		}
555 	}
556 
557 	if (avefreei) {
558 		/*
559 		 * The free-inodes counter is approximate, and for really small
560 		 * filesystems the above test can fail to find any blockgroups
561 		 */
562 		avefreei = 0;
563 		goto fallback_retry;
564 	}
565 
566 	return -1;
567 }
568 
find_group_other(struct super_block * sb,struct inode * parent,ext4_group_t * group,umode_t mode)569 static int find_group_other(struct super_block *sb, struct inode *parent,
570 			    ext4_group_t *group, umode_t mode)
571 {
572 	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
573 	ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
574 	struct ext4_group_desc *desc;
575 	int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
576 
577 	/*
578 	 * Try to place the inode is the same flex group as its
579 	 * parent.  If we can't find space, use the Orlov algorithm to
580 	 * find another flex group, and store that information in the
581 	 * parent directory's inode information so that use that flex
582 	 * group for future allocations.
583 	 */
584 	if (flex_size > 1) {
585 		int retry = 0;
586 
587 	try_again:
588 		parent_group &= ~(flex_size-1);
589 		last = parent_group + flex_size;
590 		if (last > ngroups)
591 			last = ngroups;
592 		for  (i = parent_group; i < last; i++) {
593 			desc = ext4_get_group_desc(sb, i, NULL);
594 			if (desc && ext4_free_inodes_count(sb, desc)) {
595 				*group = i;
596 				return 0;
597 			}
598 		}
599 		if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
600 			retry = 1;
601 			parent_group = EXT4_I(parent)->i_last_alloc_group;
602 			goto try_again;
603 		}
604 		/*
605 		 * If this didn't work, use the Orlov search algorithm
606 		 * to find a new flex group; we pass in the mode to
607 		 * avoid the topdir algorithms.
608 		 */
609 		*group = parent_group + flex_size;
610 		if (*group > ngroups)
611 			*group = 0;
612 		return find_group_orlov(sb, parent, group, mode, NULL);
613 	}
614 
615 	/*
616 	 * Try to place the inode in its parent directory
617 	 */
618 	*group = parent_group;
619 	desc = ext4_get_group_desc(sb, *group, NULL);
620 	if (desc && ext4_free_inodes_count(sb, desc) &&
621 	    ext4_free_group_clusters(sb, desc))
622 		return 0;
623 
624 	/*
625 	 * We're going to place this inode in a different blockgroup from its
626 	 * parent.  We want to cause files in a common directory to all land in
627 	 * the same blockgroup.  But we want files which are in a different
628 	 * directory which shares a blockgroup with our parent to land in a
629 	 * different blockgroup.
630 	 *
631 	 * So add our directory's i_ino into the starting point for the hash.
632 	 */
633 	*group = (*group + parent->i_ino) % ngroups;
634 
635 	/*
636 	 * Use a quadratic hash to find a group with a free inode and some free
637 	 * blocks.
638 	 */
639 	for (i = 1; i < ngroups; i <<= 1) {
640 		*group += i;
641 		if (*group >= ngroups)
642 			*group -= ngroups;
643 		desc = ext4_get_group_desc(sb, *group, NULL);
644 		if (desc && ext4_free_inodes_count(sb, desc) &&
645 		    ext4_free_group_clusters(sb, desc))
646 			return 0;
647 	}
648 
649 	/*
650 	 * That failed: try linear search for a free inode, even if that group
651 	 * has no free blocks.
652 	 */
653 	*group = parent_group;
654 	for (i = 0; i < ngroups; i++) {
655 		if (++*group >= ngroups)
656 			*group = 0;
657 		desc = ext4_get_group_desc(sb, *group, NULL);
658 		if (desc && ext4_free_inodes_count(sb, desc))
659 			return 0;
660 	}
661 
662 	return -1;
663 }
664 
665 /*
666  * In no journal mode, if an inode has recently been deleted, we want
667  * to avoid reusing it until we're reasonably sure the inode table
668  * block has been written back to disk.  (Yes, these values are
669  * somewhat arbitrary...)
670  */
671 #define RECENTCY_MIN	60
672 #define RECENTCY_DIRTY	300
673 
recently_deleted(struct super_block * sb,ext4_group_t group,int ino)674 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
675 {
676 	struct ext4_group_desc	*gdp;
677 	struct ext4_inode	*raw_inode;
678 	struct buffer_head	*bh;
679 	int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
680 	int offset, ret = 0;
681 	int recentcy = RECENTCY_MIN;
682 	u32 dtime, now;
683 
684 	gdp = ext4_get_group_desc(sb, group, NULL);
685 	if (unlikely(!gdp))
686 		return 0;
687 
688 	bh = sb_find_get_block(sb, ext4_inode_table(sb, gdp) +
689 		       (ino / inodes_per_block));
690 	if (!bh || !buffer_uptodate(bh))
691 		/*
692 		 * If the block is not in the buffer cache, then it
693 		 * must have been written out.
694 		 */
695 		goto out;
696 
697 	offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
698 	raw_inode = (struct ext4_inode *) (bh->b_data + offset);
699 
700 	/* i_dtime is only 32 bits on disk, but we only care about relative
701 	 * times in the range of a few minutes (i.e. long enough to sync a
702 	 * recently-deleted inode to disk), so using the low 32 bits of the
703 	 * clock (a 68 year range) is enough, see time_before32() */
704 	dtime = le32_to_cpu(raw_inode->i_dtime);
705 	now = ktime_get_real_seconds();
706 	if (buffer_dirty(bh))
707 		recentcy += RECENTCY_DIRTY;
708 
709 	if (dtime && time_before32(dtime, now) &&
710 	    time_before32(now, dtime + recentcy))
711 		ret = 1;
712 out:
713 	brelse(bh);
714 	return ret;
715 }
716 
find_inode_bit(struct super_block * sb,ext4_group_t group,struct buffer_head * bitmap,unsigned long * ino)717 static int find_inode_bit(struct super_block *sb, ext4_group_t group,
718 			  struct buffer_head *bitmap, unsigned long *ino)
719 {
720 	bool check_recently_deleted = EXT4_SB(sb)->s_journal == NULL;
721 	unsigned long recently_deleted_ino = EXT4_INODES_PER_GROUP(sb);
722 
723 next:
724 	*ino = ext4_find_next_zero_bit((unsigned long *)
725 				       bitmap->b_data,
726 				       EXT4_INODES_PER_GROUP(sb), *ino);
727 	if (*ino >= EXT4_INODES_PER_GROUP(sb))
728 		goto not_found;
729 
730 	if (check_recently_deleted && recently_deleted(sb, group, *ino)) {
731 		recently_deleted_ino = *ino;
732 		*ino = *ino + 1;
733 		if (*ino < EXT4_INODES_PER_GROUP(sb))
734 			goto next;
735 		goto not_found;
736 	}
737 	return 1;
738 not_found:
739 	if (recently_deleted_ino >= EXT4_INODES_PER_GROUP(sb))
740 		return 0;
741 	/*
742 	 * Not reusing recently deleted inodes is mostly a preference. We don't
743 	 * want to report ENOSPC or skew allocation patterns because of that.
744 	 * So return even recently deleted inode if we could find better in the
745 	 * given range.
746 	 */
747 	*ino = recently_deleted_ino;
748 	return 1;
749 }
750 
ext4_mark_inode_used(struct super_block * sb,int ino)751 int ext4_mark_inode_used(struct super_block *sb, int ino)
752 {
753 	unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
754 	struct buffer_head *inode_bitmap_bh = NULL, *group_desc_bh = NULL;
755 	struct ext4_group_desc *gdp;
756 	ext4_group_t group;
757 	int bit;
758 	int err = -EFSCORRUPTED;
759 
760 	if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
761 		goto out;
762 
763 	group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
764 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
765 	inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
766 	if (IS_ERR(inode_bitmap_bh))
767 		return PTR_ERR(inode_bitmap_bh);
768 
769 	if (ext4_test_bit(bit, inode_bitmap_bh->b_data)) {
770 		err = 0;
771 		goto out;
772 	}
773 
774 	gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
775 	if (!gdp || !group_desc_bh) {
776 		err = -EINVAL;
777 		goto out;
778 	}
779 
780 	ext4_set_bit(bit, inode_bitmap_bh->b_data);
781 
782 	BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
783 	err = ext4_handle_dirty_metadata(NULL, NULL, inode_bitmap_bh);
784 	if (err) {
785 		ext4_std_error(sb, err);
786 		goto out;
787 	}
788 	err = sync_dirty_buffer(inode_bitmap_bh);
789 	if (err) {
790 		ext4_std_error(sb, err);
791 		goto out;
792 	}
793 
794 	/* We may have to initialize the block bitmap if it isn't already */
795 	if (ext4_has_group_desc_csum(sb) &&
796 	    gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
797 		struct buffer_head *block_bitmap_bh;
798 
799 		block_bitmap_bh = ext4_read_block_bitmap(sb, group);
800 		if (IS_ERR(block_bitmap_bh)) {
801 			err = PTR_ERR(block_bitmap_bh);
802 			goto out;
803 		}
804 
805 		BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
806 		err = ext4_handle_dirty_metadata(NULL, NULL, block_bitmap_bh);
807 		sync_dirty_buffer(block_bitmap_bh);
808 
809 		/* recheck and clear flag under lock if we still need to */
810 		ext4_lock_group(sb, group);
811 		if (ext4_has_group_desc_csum(sb) &&
812 		    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
813 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
814 			ext4_free_group_clusters_set(sb, gdp,
815 				ext4_free_clusters_after_init(sb, group, gdp));
816 			ext4_block_bitmap_csum_set(sb, group, gdp,
817 						   block_bitmap_bh);
818 			ext4_group_desc_csum_set(sb, group, gdp);
819 		}
820 		ext4_unlock_group(sb, group);
821 		brelse(block_bitmap_bh);
822 
823 		if (err) {
824 			ext4_std_error(sb, err);
825 			goto out;
826 		}
827 	}
828 
829 	/* Update the relevant bg descriptor fields */
830 	if (ext4_has_group_desc_csum(sb)) {
831 		int free;
832 
833 		ext4_lock_group(sb, group); /* while we modify the bg desc */
834 		free = EXT4_INODES_PER_GROUP(sb) -
835 			ext4_itable_unused_count(sb, gdp);
836 		if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
837 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
838 			free = 0;
839 		}
840 
841 		/*
842 		 * Check the relative inode number against the last used
843 		 * relative inode number in this group. if it is greater
844 		 * we need to update the bg_itable_unused count
845 		 */
846 		if (bit >= free)
847 			ext4_itable_unused_set(sb, gdp,
848 					(EXT4_INODES_PER_GROUP(sb) - bit - 1));
849 	} else {
850 		ext4_lock_group(sb, group);
851 	}
852 
853 	ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
854 	if (ext4_has_group_desc_csum(sb)) {
855 		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
856 					   EXT4_INODES_PER_GROUP(sb) / 8);
857 		ext4_group_desc_csum_set(sb, group, gdp);
858 	}
859 
860 	ext4_unlock_group(sb, group);
861 	err = ext4_handle_dirty_metadata(NULL, NULL, group_desc_bh);
862 	sync_dirty_buffer(group_desc_bh);
863 out:
864 	return err;
865 }
866 
ext4_xattr_credits_for_new_inode(struct inode * dir,mode_t mode,bool encrypt)867 static int ext4_xattr_credits_for_new_inode(struct inode *dir, mode_t mode,
868 					    bool encrypt)
869 {
870 	struct super_block *sb = dir->i_sb;
871 	int nblocks = 0;
872 #ifdef CONFIG_EXT4_FS_POSIX_ACL
873 	struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
874 
875 	if (IS_ERR(p))
876 		return PTR_ERR(p);
877 	if (p) {
878 		int acl_size = p->a_count * sizeof(ext4_acl_entry);
879 
880 		nblocks += (S_ISDIR(mode) ? 2 : 1) *
881 			__ext4_xattr_set_credits(sb, NULL /* inode */,
882 						 NULL /* block_bh */, acl_size,
883 						 true /* is_create */);
884 		posix_acl_release(p);
885 	}
886 #endif
887 
888 #ifdef CONFIG_SECURITY
889 	{
890 		int num_security_xattrs = 1;
891 
892 #ifdef CONFIG_INTEGRITY
893 		num_security_xattrs++;
894 #endif
895 		/*
896 		 * We assume that security xattrs are never more than 1k.
897 		 * In practice they are under 128 bytes.
898 		 */
899 		nblocks += num_security_xattrs *
900 			__ext4_xattr_set_credits(sb, NULL /* inode */,
901 						 NULL /* block_bh */, 1024,
902 						 true /* is_create */);
903 	}
904 #endif
905 	if (encrypt)
906 		nblocks += __ext4_xattr_set_credits(sb,
907 						    NULL /* inode */,
908 						    NULL /* block_bh */,
909 						    FSCRYPT_SET_CONTEXT_MAX_SIZE,
910 						    true /* is_create */);
911 	return nblocks;
912 }
913 
914 /*
915  * There are two policies for allocating an inode.  If the new inode is
916  * a directory, then a forward search is made for a block group with both
917  * free space and a low directory-to-inode ratio; if that fails, then of
918  * the groups with above-average free space, that group with the fewest
919  * directories already is chosen.
920  *
921  * For other inodes, search forward from the parent directory's block
922  * group to find a free inode.
923  */
__ext4_new_inode(struct user_namespace * mnt_userns,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)924 struct inode *__ext4_new_inode(struct user_namespace *mnt_userns,
925 			       handle_t *handle, struct inode *dir,
926 			       umode_t mode, const struct qstr *qstr,
927 			       __u32 goal, uid_t *owner, __u32 i_flags,
928 			       int handle_type, unsigned int line_no,
929 			       int nblocks)
930 {
931 	struct super_block *sb;
932 	struct buffer_head *inode_bitmap_bh = NULL;
933 	struct buffer_head *group_desc_bh;
934 	ext4_group_t ngroups, group = 0;
935 	unsigned long ino = 0;
936 	struct inode *inode;
937 	struct ext4_group_desc *gdp = NULL;
938 	struct ext4_inode_info *ei;
939 	struct ext4_sb_info *sbi;
940 	int ret2, err;
941 	struct inode *ret;
942 	ext4_group_t i;
943 	ext4_group_t flex_group;
944 	struct ext4_group_info *grp = NULL;
945 	bool encrypt = false;
946 
947 	/* Cannot create files in a deleted directory */
948 	if (!dir || !dir->i_nlink)
949 		return ERR_PTR(-EPERM);
950 
951 	sb = dir->i_sb;
952 	sbi = EXT4_SB(sb);
953 
954 	if (unlikely(ext4_forced_shutdown(sbi)))
955 		return ERR_PTR(-EIO);
956 
957 	ngroups = ext4_get_groups_count(sb);
958 	trace_ext4_request_inode(dir, mode);
959 	inode = new_inode(sb);
960 	if (!inode)
961 		return ERR_PTR(-ENOMEM);
962 	ei = EXT4_I(inode);
963 
964 	/*
965 	 * Initialize owners and quota early so that we don't have to account
966 	 * for quota initialization worst case in standard inode creating
967 	 * transaction
968 	 */
969 	if (owner) {
970 		inode->i_mode = mode;
971 		i_uid_write(inode, owner[0]);
972 		i_gid_write(inode, owner[1]);
973 	} else if (test_opt(sb, GRPID)) {
974 		inode->i_mode = mode;
975 		inode_fsuid_set(inode, mnt_userns);
976 		inode->i_gid = dir->i_gid;
977 	} else
978 		inode_init_owner(mnt_userns, inode, dir, mode);
979 
980 	if (ext4_has_feature_project(sb) &&
981 	    ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
982 		ei->i_projid = EXT4_I(dir)->i_projid;
983 	else
984 		ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
985 
986 	if (!(i_flags & EXT4_EA_INODE_FL)) {
987 		err = fscrypt_prepare_new_inode(dir, inode, &encrypt);
988 		if (err)
989 			goto out;
990 	}
991 
992 	err = dquot_initialize(inode);
993 	if (err)
994 		goto out;
995 
996 	if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
997 		ret2 = ext4_xattr_credits_for_new_inode(dir, mode, encrypt);
998 		if (ret2 < 0) {
999 			err = ret2;
1000 			goto out;
1001 		}
1002 		nblocks += ret2;
1003 	}
1004 
1005 	if (!goal)
1006 		goal = sbi->s_inode_goal;
1007 
1008 	if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
1009 		group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
1010 		ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
1011 		ret2 = 0;
1012 		goto got_group;
1013 	}
1014 
1015 	if (S_ISDIR(mode))
1016 		ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
1017 	else
1018 		ret2 = find_group_other(sb, dir, &group, mode);
1019 
1020 got_group:
1021 	EXT4_I(dir)->i_last_alloc_group = group;
1022 	err = -ENOSPC;
1023 	if (ret2 == -1)
1024 		goto out;
1025 
1026 	/*
1027 	 * Normally we will only go through one pass of this loop,
1028 	 * unless we get unlucky and it turns out the group we selected
1029 	 * had its last inode grabbed by someone else.
1030 	 */
1031 	for (i = 0; i < ngroups; i++, ino = 0) {
1032 		err = -EIO;
1033 
1034 		gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1035 		if (!gdp)
1036 			goto out;
1037 
1038 		/*
1039 		 * Check free inodes count before loading bitmap.
1040 		 */
1041 		if (ext4_free_inodes_count(sb, gdp) == 0)
1042 			goto next_group;
1043 
1044 		if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
1045 			grp = ext4_get_group_info(sb, group);
1046 			/*
1047 			 * Skip groups with already-known suspicious inode
1048 			 * tables
1049 			 */
1050 			if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
1051 				goto next_group;
1052 		}
1053 
1054 		brelse(inode_bitmap_bh);
1055 		inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
1056 		/* Skip groups with suspicious inode tables */
1057 		if (((!(sbi->s_mount_state & EXT4_FC_REPLAY))
1058 		     && EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) ||
1059 		    IS_ERR(inode_bitmap_bh)) {
1060 			inode_bitmap_bh = NULL;
1061 			goto next_group;
1062 		}
1063 
1064 repeat_in_this_group:
1065 		ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
1066 		if (!ret2)
1067 			goto next_group;
1068 
1069 		if (group == 0 && (ino + 1) < EXT4_FIRST_INO(sb)) {
1070 			ext4_error(sb, "reserved inode found cleared - "
1071 				   "inode=%lu", ino + 1);
1072 			ext4_mark_group_bitmap_corrupted(sb, group,
1073 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
1074 			goto next_group;
1075 		}
1076 
1077 		if ((!(sbi->s_mount_state & EXT4_FC_REPLAY)) && !handle) {
1078 			BUG_ON(nblocks <= 0);
1079 			handle = __ext4_journal_start_sb(dir->i_sb, line_no,
1080 				 handle_type, nblocks, 0,
1081 				 ext4_trans_default_revoke_credits(sb));
1082 			if (IS_ERR(handle)) {
1083 				err = PTR_ERR(handle);
1084 				ext4_std_error(sb, err);
1085 				goto out;
1086 			}
1087 		}
1088 		BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
1089 		err = ext4_journal_get_write_access(handle, sb, inode_bitmap_bh,
1090 						    EXT4_JTR_NONE);
1091 		if (err) {
1092 			ext4_std_error(sb, err);
1093 			goto out;
1094 		}
1095 		ext4_lock_group(sb, group);
1096 		ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
1097 		if (ret2) {
1098 			/* Someone already took the bit. Repeat the search
1099 			 * with lock held.
1100 			 */
1101 			ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
1102 			if (ret2) {
1103 				ext4_set_bit(ino, inode_bitmap_bh->b_data);
1104 				ret2 = 0;
1105 			} else {
1106 				ret2 = 1; /* we didn't grab the inode */
1107 			}
1108 		}
1109 		ext4_unlock_group(sb, group);
1110 		ino++;		/* the inode bitmap is zero-based */
1111 		if (!ret2)
1112 			goto got; /* we grabbed the inode! */
1113 
1114 		if (ino < EXT4_INODES_PER_GROUP(sb))
1115 			goto repeat_in_this_group;
1116 next_group:
1117 		if (++group == ngroups)
1118 			group = 0;
1119 	}
1120 	err = -ENOSPC;
1121 	goto out;
1122 
1123 got:
1124 	BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
1125 	err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
1126 	if (err) {
1127 		ext4_std_error(sb, err);
1128 		goto out;
1129 	}
1130 
1131 	BUFFER_TRACE(group_desc_bh, "get_write_access");
1132 	err = ext4_journal_get_write_access(handle, sb, group_desc_bh,
1133 					    EXT4_JTR_NONE);
1134 	if (err) {
1135 		ext4_std_error(sb, err);
1136 		goto out;
1137 	}
1138 
1139 	/* We may have to initialize the block bitmap if it isn't already */
1140 	if (ext4_has_group_desc_csum(sb) &&
1141 	    gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
1142 		struct buffer_head *block_bitmap_bh;
1143 
1144 		block_bitmap_bh = ext4_read_block_bitmap(sb, group);
1145 		if (IS_ERR(block_bitmap_bh)) {
1146 			err = PTR_ERR(block_bitmap_bh);
1147 			goto out;
1148 		}
1149 		BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
1150 		err = ext4_journal_get_write_access(handle, sb, block_bitmap_bh,
1151 						    EXT4_JTR_NONE);
1152 		if (err) {
1153 			brelse(block_bitmap_bh);
1154 			ext4_std_error(sb, err);
1155 			goto out;
1156 		}
1157 
1158 		BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
1159 		err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
1160 
1161 		/* recheck and clear flag under lock if we still need to */
1162 		ext4_lock_group(sb, group);
1163 		if (ext4_has_group_desc_csum(sb) &&
1164 		    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
1165 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
1166 			ext4_free_group_clusters_set(sb, gdp,
1167 				ext4_free_clusters_after_init(sb, group, gdp));
1168 			ext4_block_bitmap_csum_set(sb, group, gdp,
1169 						   block_bitmap_bh);
1170 			ext4_group_desc_csum_set(sb, group, gdp);
1171 		}
1172 		ext4_unlock_group(sb, group);
1173 		brelse(block_bitmap_bh);
1174 
1175 		if (err) {
1176 			ext4_std_error(sb, err);
1177 			goto out;
1178 		}
1179 	}
1180 
1181 	/* Update the relevant bg descriptor fields */
1182 	if (ext4_has_group_desc_csum(sb)) {
1183 		int free;
1184 		struct ext4_group_info *grp = NULL;
1185 
1186 		if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
1187 			grp = ext4_get_group_info(sb, group);
1188 			down_read(&grp->alloc_sem); /*
1189 						     * protect vs itable
1190 						     * lazyinit
1191 						     */
1192 		}
1193 		ext4_lock_group(sb, group); /* while we modify the bg desc */
1194 		free = EXT4_INODES_PER_GROUP(sb) -
1195 			ext4_itable_unused_count(sb, gdp);
1196 		if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
1197 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
1198 			free = 0;
1199 		}
1200 		/*
1201 		 * Check the relative inode number against the last used
1202 		 * relative inode number in this group. if it is greater
1203 		 * we need to update the bg_itable_unused count
1204 		 */
1205 		if (ino > free)
1206 			ext4_itable_unused_set(sb, gdp,
1207 					(EXT4_INODES_PER_GROUP(sb) - ino));
1208 		if (!(sbi->s_mount_state & EXT4_FC_REPLAY))
1209 			up_read(&grp->alloc_sem);
1210 	} else {
1211 		ext4_lock_group(sb, group);
1212 	}
1213 
1214 	ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1215 	if (S_ISDIR(mode)) {
1216 		ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1217 		if (sbi->s_log_groups_per_flex) {
1218 			ext4_group_t f = ext4_flex_group(sbi, group);
1219 
1220 			atomic_inc(&sbi_array_rcu_deref(sbi, s_flex_groups,
1221 							f)->used_dirs);
1222 		}
1223 	}
1224 	if (ext4_has_group_desc_csum(sb)) {
1225 		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1226 					   EXT4_INODES_PER_GROUP(sb) / 8);
1227 		ext4_group_desc_csum_set(sb, group, gdp);
1228 	}
1229 	ext4_unlock_group(sb, group);
1230 
1231 	BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1232 	err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1233 	if (err) {
1234 		ext4_std_error(sb, err);
1235 		goto out;
1236 	}
1237 
1238 	percpu_counter_dec(&sbi->s_freeinodes_counter);
1239 	if (S_ISDIR(mode))
1240 		percpu_counter_inc(&sbi->s_dirs_counter);
1241 
1242 	if (sbi->s_log_groups_per_flex) {
1243 		flex_group = ext4_flex_group(sbi, group);
1244 		atomic_dec(&sbi_array_rcu_deref(sbi, s_flex_groups,
1245 						flex_group)->free_inodes);
1246 	}
1247 
1248 	inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1249 	/* This is the optimal IO size (for stat), not the fs block size */
1250 	inode->i_blocks = 0;
1251 	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1252 	ei->i_crtime = inode->i_mtime;
1253 
1254 	memset(ei->i_data, 0, sizeof(ei->i_data));
1255 	ei->i_dir_start_lookup = 0;
1256 	ei->i_disksize = 0;
1257 
1258 	/* Don't inherit extent flag from directory, amongst others. */
1259 	ei->i_flags =
1260 		ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1261 	ei->i_flags |= i_flags;
1262 	ei->i_file_acl = 0;
1263 	ei->i_dtime = 0;
1264 	ei->i_block_group = group;
1265 	ei->i_last_alloc_group = ~0;
1266 
1267 	ext4_set_inode_flags(inode, true);
1268 	if (IS_DIRSYNC(inode))
1269 		ext4_handle_sync(handle);
1270 	if (insert_inode_locked(inode) < 0) {
1271 		/*
1272 		 * Likely a bitmap corruption causing inode to be allocated
1273 		 * twice.
1274 		 */
1275 		err = -EIO;
1276 		ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1277 			   inode->i_ino);
1278 		ext4_mark_group_bitmap_corrupted(sb, group,
1279 					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
1280 		goto out;
1281 	}
1282 	inode->i_generation = get_random_u32();
1283 
1284 	/* Precompute checksum seed for inode metadata */
1285 	if (ext4_has_metadata_csum(sb)) {
1286 		__u32 csum;
1287 		__le32 inum = cpu_to_le32(inode->i_ino);
1288 		__le32 gen = cpu_to_le32(inode->i_generation);
1289 		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1290 				   sizeof(inum));
1291 		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1292 					      sizeof(gen));
1293 	}
1294 
1295 	ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1296 	ext4_set_inode_state(inode, EXT4_STATE_NEW);
1297 
1298 	ei->i_extra_isize = sbi->s_want_extra_isize;
1299 	ei->i_inline_off = 0;
1300 	if (ext4_has_feature_inline_data(sb) &&
1301 	    (!(ei->i_flags & EXT4_DAX_FL) || S_ISDIR(mode)))
1302 		ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1303 	ret = inode;
1304 	err = dquot_alloc_inode(inode);
1305 	if (err)
1306 		goto fail_drop;
1307 
1308 	/*
1309 	 * Since the encryption xattr will always be unique, create it first so
1310 	 * that it's less likely to end up in an external xattr block and
1311 	 * prevent its deduplication.
1312 	 */
1313 	if (encrypt) {
1314 		err = fscrypt_set_context(inode, handle);
1315 		if (err)
1316 			goto fail_free_drop;
1317 	}
1318 
1319 	if (!(ei->i_flags & EXT4_EA_INODE_FL)) {
1320 		err = ext4_init_acl(handle, inode, dir);
1321 		if (err)
1322 			goto fail_free_drop;
1323 
1324 		err = ext4_init_security(handle, inode, dir, qstr);
1325 		if (err)
1326 			goto fail_free_drop;
1327 	}
1328 
1329 	if (ext4_has_feature_extents(sb)) {
1330 		/* set extent flag only for directory, file and normal symlink*/
1331 		if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1332 			ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1333 			ext4_ext_tree_init(handle, inode);
1334 		}
1335 	}
1336 
1337 	if (ext4_handle_valid(handle)) {
1338 		ei->i_sync_tid = handle->h_transaction->t_tid;
1339 		ei->i_datasync_tid = handle->h_transaction->t_tid;
1340 	}
1341 
1342 	err = ext4_mark_inode_dirty(handle, inode);
1343 	if (err) {
1344 		ext4_std_error(sb, err);
1345 		goto fail_free_drop;
1346 	}
1347 
1348 	ext4_debug("allocating inode %lu\n", inode->i_ino);
1349 	trace_ext4_allocate_inode(inode, dir, mode);
1350 	brelse(inode_bitmap_bh);
1351 	return ret;
1352 
1353 fail_free_drop:
1354 	dquot_free_inode(inode);
1355 fail_drop:
1356 	clear_nlink(inode);
1357 	unlock_new_inode(inode);
1358 out:
1359 	dquot_drop(inode);
1360 	inode->i_flags |= S_NOQUOTA;
1361 	iput(inode);
1362 	brelse(inode_bitmap_bh);
1363 	return ERR_PTR(err);
1364 }
1365 
1366 /* Verify that we are loading a valid orphan from disk */
ext4_orphan_get(struct super_block * sb,unsigned long ino)1367 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1368 {
1369 	unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1370 	ext4_group_t block_group;
1371 	int bit;
1372 	struct buffer_head *bitmap_bh = NULL;
1373 	struct inode *inode = NULL;
1374 	int err = -EFSCORRUPTED;
1375 
1376 	if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
1377 		goto bad_orphan;
1378 
1379 	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1380 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1381 	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1382 	if (IS_ERR(bitmap_bh))
1383 		return ERR_CAST(bitmap_bh);
1384 
1385 	/* Having the inode bit set should be a 100% indicator that this
1386 	 * is a valid orphan (no e2fsck run on fs).  Orphans also include
1387 	 * inodes that were being truncated, so we can't check i_nlink==0.
1388 	 */
1389 	if (!ext4_test_bit(bit, bitmap_bh->b_data))
1390 		goto bad_orphan;
1391 
1392 	inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
1393 	if (IS_ERR(inode)) {
1394 		err = PTR_ERR(inode);
1395 		ext4_error_err(sb, -err,
1396 			       "couldn't read orphan inode %lu (err %d)",
1397 			       ino, err);
1398 		brelse(bitmap_bh);
1399 		return inode;
1400 	}
1401 
1402 	/*
1403 	 * If the orphans has i_nlinks > 0 then it should be able to
1404 	 * be truncated, otherwise it won't be removed from the orphan
1405 	 * list during processing and an infinite loop will result.
1406 	 * Similarly, it must not be a bad inode.
1407 	 */
1408 	if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
1409 	    is_bad_inode(inode))
1410 		goto bad_orphan;
1411 
1412 	if (NEXT_ORPHAN(inode) > max_ino)
1413 		goto bad_orphan;
1414 	brelse(bitmap_bh);
1415 	return inode;
1416 
1417 bad_orphan:
1418 	ext4_error(sb, "bad orphan inode %lu", ino);
1419 	if (bitmap_bh)
1420 		printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1421 		       bit, (unsigned long long)bitmap_bh->b_blocknr,
1422 		       ext4_test_bit(bit, bitmap_bh->b_data));
1423 	if (inode) {
1424 		printk(KERN_ERR "is_bad_inode(inode)=%d\n",
1425 		       is_bad_inode(inode));
1426 		printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
1427 		       NEXT_ORPHAN(inode));
1428 		printk(KERN_ERR "max_ino=%lu\n", max_ino);
1429 		printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
1430 		/* Avoid freeing blocks if we got a bad deleted inode */
1431 		if (inode->i_nlink == 0)
1432 			inode->i_blocks = 0;
1433 		iput(inode);
1434 	}
1435 	brelse(bitmap_bh);
1436 	return ERR_PTR(err);
1437 }
1438 
ext4_count_free_inodes(struct super_block * sb)1439 unsigned long ext4_count_free_inodes(struct super_block *sb)
1440 {
1441 	unsigned long desc_count;
1442 	struct ext4_group_desc *gdp;
1443 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1444 #ifdef EXT4FS_DEBUG
1445 	struct ext4_super_block *es;
1446 	unsigned long bitmap_count, x;
1447 	struct buffer_head *bitmap_bh = NULL;
1448 
1449 	es = EXT4_SB(sb)->s_es;
1450 	desc_count = 0;
1451 	bitmap_count = 0;
1452 	gdp = NULL;
1453 	for (i = 0; i < ngroups; i++) {
1454 		gdp = ext4_get_group_desc(sb, i, NULL);
1455 		if (!gdp)
1456 			continue;
1457 		desc_count += ext4_free_inodes_count(sb, gdp);
1458 		brelse(bitmap_bh);
1459 		bitmap_bh = ext4_read_inode_bitmap(sb, i);
1460 		if (IS_ERR(bitmap_bh)) {
1461 			bitmap_bh = NULL;
1462 			continue;
1463 		}
1464 
1465 		x = ext4_count_free(bitmap_bh->b_data,
1466 				    EXT4_INODES_PER_GROUP(sb) / 8);
1467 		printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1468 			(unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1469 		bitmap_count += x;
1470 	}
1471 	brelse(bitmap_bh);
1472 	printk(KERN_DEBUG "ext4_count_free_inodes: "
1473 	       "stored = %u, computed = %lu, %lu\n",
1474 	       le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1475 	return desc_count;
1476 #else
1477 	desc_count = 0;
1478 	for (i = 0; i < ngroups; i++) {
1479 		gdp = ext4_get_group_desc(sb, i, NULL);
1480 		if (!gdp)
1481 			continue;
1482 		desc_count += ext4_free_inodes_count(sb, gdp);
1483 		cond_resched();
1484 	}
1485 	return desc_count;
1486 #endif
1487 }
1488 
1489 /* Called at mount-time, super-block is locked */
ext4_count_dirs(struct super_block * sb)1490 unsigned long ext4_count_dirs(struct super_block * sb)
1491 {
1492 	unsigned long count = 0;
1493 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1494 
1495 	for (i = 0; i < ngroups; i++) {
1496 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1497 		if (!gdp)
1498 			continue;
1499 		count += ext4_used_dirs_count(sb, gdp);
1500 	}
1501 	return count;
1502 }
1503 
1504 /*
1505  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1506  * inode table. Must be called without any spinlock held. The only place
1507  * where it is called from on active part of filesystem is ext4lazyinit
1508  * thread, so we do not need any special locks, however we have to prevent
1509  * inode allocation from the current group, so we take alloc_sem lock, to
1510  * block ext4_new_inode() until we are finished.
1511  */
ext4_init_inode_table(struct super_block * sb,ext4_group_t group,int barrier)1512 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1513 				 int barrier)
1514 {
1515 	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1516 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1517 	struct ext4_group_desc *gdp = NULL;
1518 	struct buffer_head *group_desc_bh;
1519 	handle_t *handle;
1520 	ext4_fsblk_t blk;
1521 	int num, ret = 0, used_blks = 0;
1522 	unsigned long used_inos = 0;
1523 
1524 	/* This should not happen, but just to be sure check this */
1525 	if (sb_rdonly(sb)) {
1526 		ret = 1;
1527 		goto out;
1528 	}
1529 
1530 	gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1531 	if (!gdp)
1532 		goto out;
1533 
1534 	/*
1535 	 * We do not need to lock this, because we are the only one
1536 	 * handling this flag.
1537 	 */
1538 	if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1539 		goto out;
1540 
1541 	handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1542 	if (IS_ERR(handle)) {
1543 		ret = PTR_ERR(handle);
1544 		goto out;
1545 	}
1546 
1547 	down_write(&grp->alloc_sem);
1548 	/*
1549 	 * If inode bitmap was already initialized there may be some
1550 	 * used inodes so we need to skip blocks with used inodes in
1551 	 * inode table.
1552 	 */
1553 	if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
1554 		used_inos = EXT4_INODES_PER_GROUP(sb) -
1555 			    ext4_itable_unused_count(sb, gdp);
1556 		used_blks = DIV_ROUND_UP(used_inos, sbi->s_inodes_per_block);
1557 
1558 		/* Bogus inode unused count? */
1559 		if (used_blks < 0 || used_blks > sbi->s_itb_per_group) {
1560 			ext4_error(sb, "Something is wrong with group %u: "
1561 				   "used itable blocks: %d; "
1562 				   "itable unused count: %u",
1563 				   group, used_blks,
1564 				   ext4_itable_unused_count(sb, gdp));
1565 			ret = 1;
1566 			goto err_out;
1567 		}
1568 
1569 		used_inos += group * EXT4_INODES_PER_GROUP(sb);
1570 		/*
1571 		 * Are there some uninitialized inodes in the inode table
1572 		 * before the first normal inode?
1573 		 */
1574 		if ((used_blks != sbi->s_itb_per_group) &&
1575 		     (used_inos < EXT4_FIRST_INO(sb))) {
1576 			ext4_error(sb, "Something is wrong with group %u: "
1577 				   "itable unused count: %u; "
1578 				   "itables initialized count: %ld",
1579 				   group, ext4_itable_unused_count(sb, gdp),
1580 				   used_inos);
1581 			ret = 1;
1582 			goto err_out;
1583 		}
1584 	}
1585 
1586 	blk = ext4_inode_table(sb, gdp) + used_blks;
1587 	num = sbi->s_itb_per_group - used_blks;
1588 
1589 	BUFFER_TRACE(group_desc_bh, "get_write_access");
1590 	ret = ext4_journal_get_write_access(handle, sb, group_desc_bh,
1591 					    EXT4_JTR_NONE);
1592 	if (ret)
1593 		goto err_out;
1594 
1595 	/*
1596 	 * Skip zeroout if the inode table is full. But we set the ZEROED
1597 	 * flag anyway, because obviously, when it is full it does not need
1598 	 * further zeroing.
1599 	 */
1600 	if (unlikely(num == 0))
1601 		goto skip_zeroout;
1602 
1603 	ext4_debug("going to zero out inode table in group %d\n",
1604 		   group);
1605 	ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1606 	if (ret < 0)
1607 		goto err_out;
1608 	if (barrier)
1609 		blkdev_issue_flush(sb->s_bdev);
1610 
1611 skip_zeroout:
1612 	ext4_lock_group(sb, group);
1613 	gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1614 	ext4_group_desc_csum_set(sb, group, gdp);
1615 	ext4_unlock_group(sb, group);
1616 
1617 	BUFFER_TRACE(group_desc_bh,
1618 		     "call ext4_handle_dirty_metadata");
1619 	ret = ext4_handle_dirty_metadata(handle, NULL,
1620 					 group_desc_bh);
1621 
1622 err_out:
1623 	up_write(&grp->alloc_sem);
1624 	ext4_journal_stop(handle);
1625 out:
1626 	return ret;
1627 }
1628