xref: /openbmc/linux/fs/ext4/sysfs.c (revision dfc53baa)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/ext4/sysfs.c
4  *
5  * Copyright (C) 1992, 1993, 1994, 1995
6  * Remy Card (card@masi.ibp.fr)
7  * Theodore Ts'o (tytso@mit.edu)
8  *
9  */
10 
11 #include <linux/time.h>
12 #include <linux/fs.h>
13 #include <linux/seq_file.h>
14 #include <linux/slab.h>
15 #include <linux/proc_fs.h>
16 #include <linux/part_stat.h>
17 
18 #include "ext4.h"
19 #include "ext4_jbd2.h"
20 
21 typedef enum {
22 	attr_noop,
23 	attr_delayed_allocation_blocks,
24 	attr_session_write_kbytes,
25 	attr_lifetime_write_kbytes,
26 	attr_reserved_clusters,
27 	attr_inode_readahead,
28 	attr_trigger_test_error,
29 	attr_first_error_time,
30 	attr_last_error_time,
31 	attr_feature,
32 	attr_pointer_ui,
33 	attr_pointer_ul,
34 	attr_pointer_u64,
35 	attr_pointer_u8,
36 	attr_pointer_string,
37 	attr_pointer_atomic,
38 	attr_journal_task,
39 } attr_id_t;
40 
41 typedef enum {
42 	ptr_explicit,
43 	ptr_ext4_sb_info_offset,
44 	ptr_ext4_super_block_offset,
45 } attr_ptr_t;
46 
47 static const char proc_dirname[] = "fs/ext4";
48 static struct proc_dir_entry *ext4_proc_root;
49 
50 struct ext4_attr {
51 	struct attribute attr;
52 	short attr_id;
53 	short attr_ptr;
54 	unsigned short attr_size;
55 	union {
56 		int offset;
57 		void *explicit_ptr;
58 	} u;
59 };
60 
61 static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
62 {
63 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
64 
65 	if (!sb->s_bdev->bd_part)
66 		return snprintf(buf, PAGE_SIZE, "0\n");
67 	return snprintf(buf, PAGE_SIZE, "%lu\n",
68 			(part_stat_read(sb->s_bdev->bd_part,
69 					sectors[STAT_WRITE]) -
70 			 sbi->s_sectors_written_start) >> 1);
71 }
72 
73 static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
74 {
75 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
76 
77 	if (!sb->s_bdev->bd_part)
78 		return snprintf(buf, PAGE_SIZE, "0\n");
79 	return snprintf(buf, PAGE_SIZE, "%llu\n",
80 			(unsigned long long)(sbi->s_kbytes_written +
81 			((part_stat_read(sb->s_bdev->bd_part,
82 					 sectors[STAT_WRITE]) -
83 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
84 }
85 
86 static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
87 					  const char *buf, size_t count)
88 {
89 	unsigned long t;
90 	int ret;
91 
92 	ret = kstrtoul(skip_spaces(buf), 0, &t);
93 	if (ret)
94 		return ret;
95 
96 	if (t && (!is_power_of_2(t) || t > 0x40000000))
97 		return -EINVAL;
98 
99 	sbi->s_inode_readahead_blks = t;
100 	return count;
101 }
102 
103 static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
104 				   const char *buf, size_t count)
105 {
106 	unsigned long long val;
107 	ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
108 				 sbi->s_cluster_bits);
109 	int ret;
110 
111 	ret = kstrtoull(skip_spaces(buf), 0, &val);
112 	if (ret || val >= clusters)
113 		return -EINVAL;
114 
115 	atomic64_set(&sbi->s_resv_clusters, val);
116 	return count;
117 }
118 
119 static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
120 				  const char *buf, size_t count)
121 {
122 	int len = count;
123 
124 	if (!capable(CAP_SYS_ADMIN))
125 		return -EPERM;
126 
127 	if (len && buf[len-1] == '\n')
128 		len--;
129 
130 	if (len)
131 		ext4_error(sbi->s_sb, "%.*s", len, buf);
132 	return count;
133 }
134 
135 static ssize_t journal_task_show(struct ext4_sb_info *sbi, char *buf)
136 {
137 	if (!sbi->s_journal)
138 		return snprintf(buf, PAGE_SIZE, "<none>\n");
139 	return snprintf(buf, PAGE_SIZE, "%d\n",
140 			task_pid_vnr(sbi->s_journal->j_task));
141 }
142 
143 #define EXT4_ATTR(_name,_mode,_id)					\
144 static struct ext4_attr ext4_attr_##_name = {				\
145 	.attr = {.name = __stringify(_name), .mode = _mode },		\
146 	.attr_id = attr_##_id,						\
147 }
148 
149 #define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
150 
151 #define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
152 
153 #define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)	\
154 static struct ext4_attr ext4_attr_##_name = {			\
155 	.attr = {.name = __stringify(_name), .mode = _mode },	\
156 	.attr_id = attr_##_id,					\
157 	.attr_ptr = ptr_##_struct##_offset,			\
158 	.u = {							\
159 		.offset = offsetof(struct _struct, _elname),\
160 	},							\
161 }
162 
163 #define EXT4_ATTR_STRING(_name,_mode,_size,_struct,_elname)	\
164 static struct ext4_attr ext4_attr_##_name = {			\
165 	.attr = {.name = __stringify(_name), .mode = _mode },	\
166 	.attr_id = attr_pointer_string,				\
167 	.attr_size = _size,					\
168 	.attr_ptr = ptr_##_struct##_offset,			\
169 	.u = {							\
170 		.offset = offsetof(struct _struct, _elname),\
171 	},							\
172 }
173 
174 #define EXT4_RO_ATTR_ES_UI(_name,_elname)				\
175 	EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
176 
177 #define EXT4_RO_ATTR_ES_U8(_name,_elname)				\
178 	EXT4_ATTR_OFFSET(_name, 0444, pointer_u8, ext4_super_block, _elname)
179 
180 #define EXT4_RO_ATTR_ES_U64(_name,_elname)				\
181 	EXT4_ATTR_OFFSET(_name, 0444, pointer_u64, ext4_super_block, _elname)
182 
183 #define EXT4_RO_ATTR_ES_STRING(_name,_elname,_size)			\
184 	EXT4_ATTR_STRING(_name, 0444, _size, ext4_super_block, _elname)
185 
186 #define EXT4_RW_ATTR_SBI_UI(_name,_elname)	\
187 	EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
188 
189 #define EXT4_RW_ATTR_SBI_UL(_name,_elname)	\
190 	EXT4_ATTR_OFFSET(_name, 0644, pointer_ul, ext4_sb_info, _elname)
191 
192 #define EXT4_RO_ATTR_SBI_ATOMIC(_name,_elname)	\
193 	EXT4_ATTR_OFFSET(_name, 0444, pointer_atomic, ext4_sb_info, _elname)
194 
195 #define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
196 static struct ext4_attr ext4_attr_##_name = {			\
197 	.attr = {.name = __stringify(_name), .mode = _mode },	\
198 	.attr_id = attr_##_id,					\
199 	.attr_ptr = ptr_explicit,				\
200 	.u = {							\
201 		.explicit_ptr = _ptr,				\
202 	},							\
203 }
204 
205 #define ATTR_LIST(name) &ext4_attr_##name.attr
206 
207 EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
208 EXT4_ATTR_FUNC(session_write_kbytes, 0444);
209 EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
210 EXT4_ATTR_FUNC(reserved_clusters, 0644);
211 
212 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
213 		 ext4_sb_info, s_inode_readahead_blks);
214 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
215 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
216 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
217 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
218 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
219 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
220 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
221 EXT4_RW_ATTR_SBI_UI(mb_max_inode_prealloc, s_mb_max_inode_prealloc);
222 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
223 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
224 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
225 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
226 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
227 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
228 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
229 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
230 #ifdef CONFIG_EXT4_DEBUG
231 EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail);
232 #endif
233 EXT4_RO_ATTR_SBI_ATOMIC(warning_count, s_warning_count);
234 EXT4_RO_ATTR_SBI_ATOMIC(msg_count, s_msg_count);
235 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
236 EXT4_RO_ATTR_ES_U8(first_error_errcode, s_first_error_errcode);
237 EXT4_RO_ATTR_ES_U8(last_error_errcode, s_last_error_errcode);
238 EXT4_RO_ATTR_ES_UI(first_error_ino, s_first_error_ino);
239 EXT4_RO_ATTR_ES_UI(last_error_ino, s_last_error_ino);
240 EXT4_RO_ATTR_ES_U64(first_error_block, s_first_error_block);
241 EXT4_RO_ATTR_ES_U64(last_error_block, s_last_error_block);
242 EXT4_RO_ATTR_ES_UI(first_error_line, s_first_error_line);
243 EXT4_RO_ATTR_ES_UI(last_error_line, s_last_error_line);
244 EXT4_RO_ATTR_ES_STRING(first_error_func, s_first_error_func, 32);
245 EXT4_RO_ATTR_ES_STRING(last_error_func, s_last_error_func, 32);
246 EXT4_ATTR(first_error_time, 0444, first_error_time);
247 EXT4_ATTR(last_error_time, 0444, last_error_time);
248 EXT4_ATTR(journal_task, 0444, journal_task);
249 EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch);
250 EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit);
251 
252 static unsigned int old_bump_val = 128;
253 EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
254 
255 static struct attribute *ext4_attrs[] = {
256 	ATTR_LIST(delayed_allocation_blocks),
257 	ATTR_LIST(session_write_kbytes),
258 	ATTR_LIST(lifetime_write_kbytes),
259 	ATTR_LIST(reserved_clusters),
260 	ATTR_LIST(inode_readahead_blks),
261 	ATTR_LIST(inode_goal),
262 	ATTR_LIST(mb_stats),
263 	ATTR_LIST(mb_max_to_scan),
264 	ATTR_LIST(mb_min_to_scan),
265 	ATTR_LIST(mb_order2_req),
266 	ATTR_LIST(mb_stream_req),
267 	ATTR_LIST(mb_group_prealloc),
268 	ATTR_LIST(mb_max_inode_prealloc),
269 	ATTR_LIST(max_writeback_mb_bump),
270 	ATTR_LIST(extent_max_zeroout_kb),
271 	ATTR_LIST(trigger_fs_error),
272 	ATTR_LIST(err_ratelimit_interval_ms),
273 	ATTR_LIST(err_ratelimit_burst),
274 	ATTR_LIST(warning_ratelimit_interval_ms),
275 	ATTR_LIST(warning_ratelimit_burst),
276 	ATTR_LIST(msg_ratelimit_interval_ms),
277 	ATTR_LIST(msg_ratelimit_burst),
278 	ATTR_LIST(errors_count),
279 	ATTR_LIST(warning_count),
280 	ATTR_LIST(msg_count),
281 	ATTR_LIST(first_error_ino),
282 	ATTR_LIST(last_error_ino),
283 	ATTR_LIST(first_error_block),
284 	ATTR_LIST(last_error_block),
285 	ATTR_LIST(first_error_line),
286 	ATTR_LIST(last_error_line),
287 	ATTR_LIST(first_error_func),
288 	ATTR_LIST(last_error_func),
289 	ATTR_LIST(first_error_errcode),
290 	ATTR_LIST(last_error_errcode),
291 	ATTR_LIST(first_error_time),
292 	ATTR_LIST(last_error_time),
293 	ATTR_LIST(journal_task),
294 #ifdef CONFIG_EXT4_DEBUG
295 	ATTR_LIST(simulate_fail),
296 #endif
297 	ATTR_LIST(mb_prefetch),
298 	ATTR_LIST(mb_prefetch_limit),
299 	NULL,
300 };
301 ATTRIBUTE_GROUPS(ext4);
302 
303 /* Features this copy of ext4 supports */
304 EXT4_ATTR_FEATURE(lazy_itable_init);
305 EXT4_ATTR_FEATURE(batched_discard);
306 EXT4_ATTR_FEATURE(meta_bg_resize);
307 #ifdef CONFIG_FS_ENCRYPTION
308 EXT4_ATTR_FEATURE(encryption);
309 EXT4_ATTR_FEATURE(test_dummy_encryption_v2);
310 #endif
311 #ifdef CONFIG_UNICODE
312 EXT4_ATTR_FEATURE(casefold);
313 #endif
314 #ifdef CONFIG_FS_VERITY
315 EXT4_ATTR_FEATURE(verity);
316 #endif
317 EXT4_ATTR_FEATURE(metadata_csum_seed);
318 
319 static struct attribute *ext4_feat_attrs[] = {
320 	ATTR_LIST(lazy_itable_init),
321 	ATTR_LIST(batched_discard),
322 	ATTR_LIST(meta_bg_resize),
323 #ifdef CONFIG_FS_ENCRYPTION
324 	ATTR_LIST(encryption),
325 	ATTR_LIST(test_dummy_encryption_v2),
326 #endif
327 #ifdef CONFIG_UNICODE
328 	ATTR_LIST(casefold),
329 #endif
330 #ifdef CONFIG_FS_VERITY
331 	ATTR_LIST(verity),
332 #endif
333 	ATTR_LIST(metadata_csum_seed),
334 	NULL,
335 };
336 ATTRIBUTE_GROUPS(ext4_feat);
337 
338 static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
339 {
340 	switch (a->attr_ptr) {
341 	case ptr_explicit:
342 		return a->u.explicit_ptr;
343 	case ptr_ext4_sb_info_offset:
344 		return (void *) (((char *) sbi) + a->u.offset);
345 	case ptr_ext4_super_block_offset:
346 		return (void *) (((char *) sbi->s_es) + a->u.offset);
347 	}
348 	return NULL;
349 }
350 
351 static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
352 {
353 	return snprintf(buf, PAGE_SIZE, "%lld\n",
354 			((time64_t)hi << 32) + le32_to_cpu(lo));
355 }
356 
357 #define print_tstamp(buf, es, tstamp) \
358 	__print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
359 
360 static ssize_t ext4_attr_show(struct kobject *kobj,
361 			      struct attribute *attr, char *buf)
362 {
363 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
364 						s_kobj);
365 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
366 	void *ptr = calc_ptr(a, sbi);
367 
368 	switch (a->attr_id) {
369 	case attr_delayed_allocation_blocks:
370 		return snprintf(buf, PAGE_SIZE, "%llu\n",
371 				(s64) EXT4_C2B(sbi,
372 		       percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
373 	case attr_session_write_kbytes:
374 		return session_write_kbytes_show(sbi, buf);
375 	case attr_lifetime_write_kbytes:
376 		return lifetime_write_kbytes_show(sbi, buf);
377 	case attr_reserved_clusters:
378 		return snprintf(buf, PAGE_SIZE, "%llu\n",
379 				(unsigned long long)
380 				atomic64_read(&sbi->s_resv_clusters));
381 	case attr_inode_readahead:
382 	case attr_pointer_ui:
383 		if (!ptr)
384 			return 0;
385 		if (a->attr_ptr == ptr_ext4_super_block_offset)
386 			return snprintf(buf, PAGE_SIZE, "%u\n",
387 					le32_to_cpup(ptr));
388 		else
389 			return snprintf(buf, PAGE_SIZE, "%u\n",
390 					*((unsigned int *) ptr));
391 	case attr_pointer_ul:
392 		if (!ptr)
393 			return 0;
394 		return snprintf(buf, PAGE_SIZE, "%lu\n",
395 				*((unsigned long *) ptr));
396 	case attr_pointer_u8:
397 		if (!ptr)
398 			return 0;
399 		return snprintf(buf, PAGE_SIZE, "%u\n",
400 				*((unsigned char *) ptr));
401 	case attr_pointer_u64:
402 		if (!ptr)
403 			return 0;
404 		if (a->attr_ptr == ptr_ext4_super_block_offset)
405 			return snprintf(buf, PAGE_SIZE, "%llu\n",
406 					le64_to_cpup(ptr));
407 		else
408 			return snprintf(buf, PAGE_SIZE, "%llu\n",
409 					*((unsigned long long *) ptr));
410 	case attr_pointer_string:
411 		if (!ptr)
412 			return 0;
413 		return snprintf(buf, PAGE_SIZE, "%.*s\n", a->attr_size,
414 				(char *) ptr);
415 	case attr_pointer_atomic:
416 		if (!ptr)
417 			return 0;
418 		return snprintf(buf, PAGE_SIZE, "%d\n",
419 				atomic_read((atomic_t *) ptr));
420 	case attr_feature:
421 		return snprintf(buf, PAGE_SIZE, "supported\n");
422 	case attr_first_error_time:
423 		return print_tstamp(buf, sbi->s_es, s_first_error_time);
424 	case attr_last_error_time:
425 		return print_tstamp(buf, sbi->s_es, s_last_error_time);
426 	case attr_journal_task:
427 		return journal_task_show(sbi, buf);
428 	}
429 
430 	return 0;
431 }
432 
433 static ssize_t ext4_attr_store(struct kobject *kobj,
434 			       struct attribute *attr,
435 			       const char *buf, size_t len)
436 {
437 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
438 						s_kobj);
439 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
440 	void *ptr = calc_ptr(a, sbi);
441 	unsigned long t;
442 	int ret;
443 
444 	switch (a->attr_id) {
445 	case attr_reserved_clusters:
446 		return reserved_clusters_store(sbi, buf, len);
447 	case attr_pointer_ui:
448 		if (!ptr)
449 			return 0;
450 		ret = kstrtoul(skip_spaces(buf), 0, &t);
451 		if (ret)
452 			return ret;
453 		if (a->attr_ptr == ptr_ext4_super_block_offset)
454 			*((__le32 *) ptr) = cpu_to_le32(t);
455 		else
456 			*((unsigned int *) ptr) = t;
457 		return len;
458 	case attr_pointer_ul:
459 		if (!ptr)
460 			return 0;
461 		ret = kstrtoul(skip_spaces(buf), 0, &t);
462 		if (ret)
463 			return ret;
464 		*((unsigned long *) ptr) = t;
465 		return len;
466 	case attr_inode_readahead:
467 		return inode_readahead_blks_store(sbi, buf, len);
468 	case attr_trigger_test_error:
469 		return trigger_test_error(sbi, buf, len);
470 	}
471 	return 0;
472 }
473 
474 static void ext4_sb_release(struct kobject *kobj)
475 {
476 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
477 						s_kobj);
478 	complete(&sbi->s_kobj_unregister);
479 }
480 
481 static const struct sysfs_ops ext4_attr_ops = {
482 	.show	= ext4_attr_show,
483 	.store	= ext4_attr_store,
484 };
485 
486 static struct kobj_type ext4_sb_ktype = {
487 	.default_groups = ext4_groups,
488 	.sysfs_ops	= &ext4_attr_ops,
489 	.release	= ext4_sb_release,
490 };
491 
492 static struct kobj_type ext4_feat_ktype = {
493 	.default_groups = ext4_feat_groups,
494 	.sysfs_ops	= &ext4_attr_ops,
495 	.release	= (void (*)(struct kobject *))kfree,
496 };
497 
498 static struct kobject *ext4_root;
499 
500 static struct kobject *ext4_feat;
501 
502 int ext4_register_sysfs(struct super_block *sb)
503 {
504 	struct ext4_sb_info *sbi = EXT4_SB(sb);
505 	int err;
506 
507 	init_completion(&sbi->s_kobj_unregister);
508 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
509 				   "%s", sb->s_id);
510 	if (err) {
511 		kobject_put(&sbi->s_kobj);
512 		wait_for_completion(&sbi->s_kobj_unregister);
513 		return err;
514 	}
515 
516 	if (ext4_proc_root)
517 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
518 	if (sbi->s_proc) {
519 		proc_create_single_data("options", S_IRUGO, sbi->s_proc,
520 				ext4_seq_options_show, sb);
521 		proc_create_single_data("es_shrinker_info", S_IRUGO,
522 				sbi->s_proc, ext4_seq_es_shrinker_info_show,
523 				sb);
524 		proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
525 				&ext4_mb_seq_groups_ops, sb);
526 	}
527 	return 0;
528 }
529 
530 void ext4_unregister_sysfs(struct super_block *sb)
531 {
532 	struct ext4_sb_info *sbi = EXT4_SB(sb);
533 
534 	if (sbi->s_proc)
535 		remove_proc_subtree(sb->s_id, ext4_proc_root);
536 	kobject_del(&sbi->s_kobj);
537 }
538 
539 int __init ext4_init_sysfs(void)
540 {
541 	int ret;
542 
543 	ext4_root = kobject_create_and_add("ext4", fs_kobj);
544 	if (!ext4_root)
545 		return -ENOMEM;
546 
547 	ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
548 	if (!ext4_feat) {
549 		ret = -ENOMEM;
550 		goto root_err;
551 	}
552 
553 	ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
554 				   ext4_root, "features");
555 	if (ret)
556 		goto feat_err;
557 
558 	ext4_proc_root = proc_mkdir(proc_dirname, NULL);
559 	return ret;
560 
561 feat_err:
562 	kobject_put(ext4_feat);
563 	ext4_feat = NULL;
564 root_err:
565 	kobject_put(ext4_root);
566 	ext4_root = NULL;
567 	return ret;
568 }
569 
570 void ext4_exit_sysfs(void)
571 {
572 	kobject_put(ext4_feat);
573 	ext4_feat = NULL;
574 	kobject_put(ext4_root);
575 	ext4_root = NULL;
576 	remove_proc_entry(proc_dirname, NULL);
577 	ext4_proc_root = NULL;
578 }
579 
580