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 
17 #include "ext4.h"
18 #include "ext4_jbd2.h"
19 
20 typedef enum {
21 	attr_noop,
22 	attr_delayed_allocation_blocks,
23 	attr_session_write_kbytes,
24 	attr_lifetime_write_kbytes,
25 	attr_reserved_clusters,
26 	attr_inode_readahead,
27 	attr_trigger_test_error,
28 	attr_first_error_time,
29 	attr_last_error_time,
30 	attr_feature,
31 	attr_pointer_ui,
32 	attr_pointer_atomic,
33 } attr_id_t;
34 
35 typedef enum {
36 	ptr_explicit,
37 	ptr_ext4_sb_info_offset,
38 	ptr_ext4_super_block_offset,
39 } attr_ptr_t;
40 
41 static const char proc_dirname[] = "fs/ext4";
42 static struct proc_dir_entry *ext4_proc_root;
43 
44 struct ext4_attr {
45 	struct attribute attr;
46 	short attr_id;
47 	short attr_ptr;
48 	union {
49 		int offset;
50 		void *explicit_ptr;
51 	} u;
52 };
53 
session_write_kbytes_show(struct ext4_sb_info * sbi,char * buf)54 static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
55 {
56 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
57 
58 	if (!sb->s_bdev->bd_part)
59 		return snprintf(buf, PAGE_SIZE, "0\n");
60 	return snprintf(buf, PAGE_SIZE, "%lu\n",
61 			(part_stat_read(sb->s_bdev->bd_part,
62 					sectors[STAT_WRITE]) -
63 			 sbi->s_sectors_written_start) >> 1);
64 }
65 
lifetime_write_kbytes_show(struct ext4_sb_info * sbi,char * buf)66 static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
67 {
68 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
69 
70 	if (!sb->s_bdev->bd_part)
71 		return snprintf(buf, PAGE_SIZE, "0\n");
72 	return snprintf(buf, PAGE_SIZE, "%llu\n",
73 			(unsigned long long)(sbi->s_kbytes_written +
74 			((part_stat_read(sb->s_bdev->bd_part,
75 					 sectors[STAT_WRITE]) -
76 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
77 }
78 
inode_readahead_blks_store(struct ext4_sb_info * sbi,const char * buf,size_t count)79 static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
80 					  const char *buf, size_t count)
81 {
82 	unsigned long t;
83 	int ret;
84 
85 	ret = kstrtoul(skip_spaces(buf), 0, &t);
86 	if (ret)
87 		return ret;
88 
89 	if (t && (!is_power_of_2(t) || t > 0x40000000))
90 		return -EINVAL;
91 
92 	sbi->s_inode_readahead_blks = t;
93 	return count;
94 }
95 
reserved_clusters_store(struct ext4_sb_info * sbi,const char * buf,size_t count)96 static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
97 				   const char *buf, size_t count)
98 {
99 	unsigned long long val;
100 	ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
101 				 sbi->s_cluster_bits);
102 	int ret;
103 
104 	ret = kstrtoull(skip_spaces(buf), 0, &val);
105 	if (ret || val >= clusters)
106 		return -EINVAL;
107 
108 	atomic64_set(&sbi->s_resv_clusters, val);
109 	return count;
110 }
111 
trigger_test_error(struct ext4_sb_info * sbi,const char * buf,size_t count)112 static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
113 				  const char *buf, size_t count)
114 {
115 	int len = count;
116 
117 	if (!capable(CAP_SYS_ADMIN))
118 		return -EPERM;
119 
120 	if (len && buf[len-1] == '\n')
121 		len--;
122 
123 	if (len)
124 		ext4_error(sbi->s_sb, "%.*s", len, buf);
125 	return count;
126 }
127 
128 #define EXT4_ATTR(_name,_mode,_id)					\
129 static struct ext4_attr ext4_attr_##_name = {				\
130 	.attr = {.name = __stringify(_name), .mode = _mode },		\
131 	.attr_id = attr_##_id,						\
132 }
133 
134 #define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
135 
136 #define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
137 
138 #define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)	\
139 static struct ext4_attr ext4_attr_##_name = {			\
140 	.attr = {.name = __stringify(_name), .mode = _mode },	\
141 	.attr_id = attr_##_id,					\
142 	.attr_ptr = ptr_##_struct##_offset,			\
143 	.u = {							\
144 		.offset = offsetof(struct _struct, _elname),\
145 	},							\
146 }
147 
148 #define EXT4_RO_ATTR_ES_UI(_name,_elname)				\
149 	EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
150 
151 #define EXT4_RW_ATTR_SBI_UI(_name,_elname)	\
152 	EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
153 
154 #define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
155 static struct ext4_attr ext4_attr_##_name = {			\
156 	.attr = {.name = __stringify(_name), .mode = _mode },	\
157 	.attr_id = attr_##_id,					\
158 	.attr_ptr = ptr_explicit,				\
159 	.u = {							\
160 		.explicit_ptr = _ptr,				\
161 	},							\
162 }
163 
164 #define ATTR_LIST(name) &ext4_attr_##name.attr
165 
166 EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
167 EXT4_ATTR_FUNC(session_write_kbytes, 0444);
168 EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
169 EXT4_ATTR_FUNC(reserved_clusters, 0644);
170 
171 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
172 		 ext4_sb_info, s_inode_readahead_blks);
173 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
174 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
175 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
176 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
177 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
178 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
179 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
180 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
181 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
182 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
183 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
184 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
185 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
186 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
187 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
188 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
189 EXT4_ATTR(first_error_time, 0444, first_error_time);
190 EXT4_ATTR(last_error_time, 0444, last_error_time);
191 
192 static unsigned int old_bump_val = 128;
193 EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
194 
195 static struct attribute *ext4_attrs[] = {
196 	ATTR_LIST(delayed_allocation_blocks),
197 	ATTR_LIST(session_write_kbytes),
198 	ATTR_LIST(lifetime_write_kbytes),
199 	ATTR_LIST(reserved_clusters),
200 	ATTR_LIST(inode_readahead_blks),
201 	ATTR_LIST(inode_goal),
202 	ATTR_LIST(mb_stats),
203 	ATTR_LIST(mb_max_to_scan),
204 	ATTR_LIST(mb_min_to_scan),
205 	ATTR_LIST(mb_order2_req),
206 	ATTR_LIST(mb_stream_req),
207 	ATTR_LIST(mb_group_prealloc),
208 	ATTR_LIST(max_writeback_mb_bump),
209 	ATTR_LIST(extent_max_zeroout_kb),
210 	ATTR_LIST(trigger_fs_error),
211 	ATTR_LIST(err_ratelimit_interval_ms),
212 	ATTR_LIST(err_ratelimit_burst),
213 	ATTR_LIST(warning_ratelimit_interval_ms),
214 	ATTR_LIST(warning_ratelimit_burst),
215 	ATTR_LIST(msg_ratelimit_interval_ms),
216 	ATTR_LIST(msg_ratelimit_burst),
217 	ATTR_LIST(errors_count),
218 	ATTR_LIST(first_error_time),
219 	ATTR_LIST(last_error_time),
220 	NULL,
221 };
222 
223 /* Features this copy of ext4 supports */
224 EXT4_ATTR_FEATURE(lazy_itable_init);
225 EXT4_ATTR_FEATURE(batched_discard);
226 EXT4_ATTR_FEATURE(meta_bg_resize);
227 #ifdef CONFIG_EXT4_FS_ENCRYPTION
228 EXT4_ATTR_FEATURE(encryption);
229 #endif
230 EXT4_ATTR_FEATURE(metadata_csum_seed);
231 
232 static struct attribute *ext4_feat_attrs[] = {
233 	ATTR_LIST(lazy_itable_init),
234 	ATTR_LIST(batched_discard),
235 	ATTR_LIST(meta_bg_resize),
236 #ifdef CONFIG_EXT4_FS_ENCRYPTION
237 	ATTR_LIST(encryption),
238 #endif
239 	ATTR_LIST(metadata_csum_seed),
240 	NULL,
241 };
242 
calc_ptr(struct ext4_attr * a,struct ext4_sb_info * sbi)243 static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
244 {
245 	switch (a->attr_ptr) {
246 	case ptr_explicit:
247 		return a->u.explicit_ptr;
248 	case ptr_ext4_sb_info_offset:
249 		return (void *) (((char *) sbi) + a->u.offset);
250 	case ptr_ext4_super_block_offset:
251 		return (void *) (((char *) sbi->s_es) + a->u.offset);
252 	}
253 	return NULL;
254 }
255 
__print_tstamp(char * buf,__le32 lo,__u8 hi)256 static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
257 {
258 	return snprintf(buf, PAGE_SIZE, "%lld",
259 			((time64_t)hi << 32) + le32_to_cpu(lo));
260 }
261 
262 #define print_tstamp(buf, es, tstamp) \
263 	__print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
264 
ext4_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)265 static ssize_t ext4_attr_show(struct kobject *kobj,
266 			      struct attribute *attr, char *buf)
267 {
268 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
269 						s_kobj);
270 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
271 	void *ptr = calc_ptr(a, sbi);
272 
273 	switch (a->attr_id) {
274 	case attr_delayed_allocation_blocks:
275 		return snprintf(buf, PAGE_SIZE, "%llu\n",
276 				(s64) EXT4_C2B(sbi,
277 		       percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
278 	case attr_session_write_kbytes:
279 		return session_write_kbytes_show(sbi, buf);
280 	case attr_lifetime_write_kbytes:
281 		return lifetime_write_kbytes_show(sbi, buf);
282 	case attr_reserved_clusters:
283 		return snprintf(buf, PAGE_SIZE, "%llu\n",
284 				(unsigned long long)
285 				atomic64_read(&sbi->s_resv_clusters));
286 	case attr_inode_readahead:
287 	case attr_pointer_ui:
288 		if (!ptr)
289 			return 0;
290 		if (a->attr_ptr == ptr_ext4_super_block_offset)
291 			return snprintf(buf, PAGE_SIZE, "%u\n",
292 					le32_to_cpup(ptr));
293 		else
294 			return snprintf(buf, PAGE_SIZE, "%u\n",
295 					*((unsigned int *) ptr));
296 	case attr_pointer_atomic:
297 		if (!ptr)
298 			return 0;
299 		return snprintf(buf, PAGE_SIZE, "%d\n",
300 				atomic_read((atomic_t *) ptr));
301 	case attr_feature:
302 		return snprintf(buf, PAGE_SIZE, "supported\n");
303 	case attr_first_error_time:
304 		return print_tstamp(buf, sbi->s_es, s_first_error_time);
305 	case attr_last_error_time:
306 		return print_tstamp(buf, sbi->s_es, s_last_error_time);
307 	}
308 
309 	return 0;
310 }
311 
ext4_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t len)312 static ssize_t ext4_attr_store(struct kobject *kobj,
313 			       struct attribute *attr,
314 			       const char *buf, size_t len)
315 {
316 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
317 						s_kobj);
318 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
319 	void *ptr = calc_ptr(a, sbi);
320 	unsigned long t;
321 	int ret;
322 
323 	switch (a->attr_id) {
324 	case attr_reserved_clusters:
325 		return reserved_clusters_store(sbi, buf, len);
326 	case attr_pointer_ui:
327 		if (!ptr)
328 			return 0;
329 		ret = kstrtoul(skip_spaces(buf), 0, &t);
330 		if (ret)
331 			return ret;
332 		if (a->attr_ptr == ptr_ext4_super_block_offset)
333 			*((__le32 *) ptr) = cpu_to_le32(t);
334 		else
335 			*((unsigned int *) ptr) = t;
336 		return len;
337 	case attr_inode_readahead:
338 		return inode_readahead_blks_store(sbi, buf, len);
339 	case attr_trigger_test_error:
340 		return trigger_test_error(sbi, buf, len);
341 	}
342 	return 0;
343 }
344 
ext4_sb_release(struct kobject * kobj)345 static void ext4_sb_release(struct kobject *kobj)
346 {
347 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
348 						s_kobj);
349 	complete(&sbi->s_kobj_unregister);
350 }
351 
ext4_feat_release(struct kobject * kobj)352 static void ext4_feat_release(struct kobject *kobj)
353 {
354 	kfree(kobj);
355 }
356 
357 static const struct sysfs_ops ext4_attr_ops = {
358 	.show	= ext4_attr_show,
359 	.store	= ext4_attr_store,
360 };
361 
362 static struct kobj_type ext4_sb_ktype = {
363 	.default_attrs	= ext4_attrs,
364 	.sysfs_ops	= &ext4_attr_ops,
365 	.release	= ext4_sb_release,
366 };
367 
368 static struct kobj_type ext4_feat_ktype = {
369 	.default_attrs	= ext4_feat_attrs,
370 	.sysfs_ops	= &ext4_attr_ops,
371 	.release	= ext4_feat_release,
372 };
373 
374 static struct kobject *ext4_root;
375 
376 static struct kobject *ext4_feat;
377 
ext4_register_sysfs(struct super_block * sb)378 int ext4_register_sysfs(struct super_block *sb)
379 {
380 	struct ext4_sb_info *sbi = EXT4_SB(sb);
381 	int err;
382 
383 	init_completion(&sbi->s_kobj_unregister);
384 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
385 				   "%s", sb->s_id);
386 	if (err) {
387 		kobject_put(&sbi->s_kobj);
388 		wait_for_completion(&sbi->s_kobj_unregister);
389 		return err;
390 	}
391 
392 	if (ext4_proc_root)
393 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
394 	if (sbi->s_proc) {
395 		proc_create_single_data("options", S_IRUGO, sbi->s_proc,
396 				ext4_seq_options_show, sb);
397 		proc_create_single_data("es_shrinker_info", S_IRUGO,
398 				sbi->s_proc, ext4_seq_es_shrinker_info_show,
399 				sb);
400 		proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
401 				&ext4_mb_seq_groups_ops, sb);
402 	}
403 	return 0;
404 }
405 
ext4_unregister_sysfs(struct super_block * sb)406 void ext4_unregister_sysfs(struct super_block *sb)
407 {
408 	struct ext4_sb_info *sbi = EXT4_SB(sb);
409 
410 	if (sbi->s_proc)
411 		remove_proc_subtree(sb->s_id, ext4_proc_root);
412 	kobject_del(&sbi->s_kobj);
413 }
414 
ext4_init_sysfs(void)415 int __init ext4_init_sysfs(void)
416 {
417 	int ret;
418 
419 	ext4_root = kobject_create_and_add("ext4", fs_kobj);
420 	if (!ext4_root)
421 		return -ENOMEM;
422 
423 	ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
424 	if (!ext4_feat) {
425 		ret = -ENOMEM;
426 		goto root_err;
427 	}
428 
429 	ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
430 				   ext4_root, "features");
431 	if (ret)
432 		goto feat_err;
433 
434 	ext4_proc_root = proc_mkdir(proc_dirname, NULL);
435 	return ret;
436 
437 feat_err:
438 	kobject_put(ext4_feat);
439 	ext4_feat = NULL;
440 root_err:
441 	kobject_put(ext4_root);
442 	ext4_root = NULL;
443 	return ret;
444 }
445 
ext4_exit_sysfs(void)446 void ext4_exit_sysfs(void)
447 {
448 	kobject_put(ext4_feat);
449 	ext4_feat = NULL;
450 	kobject_put(ext4_root);
451 	ext4_root = NULL;
452 	remove_proc_entry(proc_dirname, NULL);
453 	ext4_proc_root = NULL;
454 }
455 
456