xref: /openbmc/linux/fs/btrfs/sysfs.c (revision 609e478b)
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/spinlock.h>
22 #include <linux/completion.h>
23 #include <linux/buffer_head.h>
24 #include <linux/kobject.h>
25 #include <linux/bug.h>
26 #include <linux/genhd.h>
27 #include <linux/debugfs.h>
28 
29 #include "ctree.h"
30 #include "disk-io.h"
31 #include "transaction.h"
32 #include "sysfs.h"
33 #include "volumes.h"
34 
35 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
36 
37 static u64 get_features(struct btrfs_fs_info *fs_info,
38 			enum btrfs_feature_set set)
39 {
40 	struct btrfs_super_block *disk_super = fs_info->super_copy;
41 	if (set == FEAT_COMPAT)
42 		return btrfs_super_compat_flags(disk_super);
43 	else if (set == FEAT_COMPAT_RO)
44 		return btrfs_super_compat_ro_flags(disk_super);
45 	else
46 		return btrfs_super_incompat_flags(disk_super);
47 }
48 
49 static void set_features(struct btrfs_fs_info *fs_info,
50 			 enum btrfs_feature_set set, u64 features)
51 {
52 	struct btrfs_super_block *disk_super = fs_info->super_copy;
53 	if (set == FEAT_COMPAT)
54 		btrfs_set_super_compat_flags(disk_super, features);
55 	else if (set == FEAT_COMPAT_RO)
56 		btrfs_set_super_compat_ro_flags(disk_super, features);
57 	else
58 		btrfs_set_super_incompat_flags(disk_super, features);
59 }
60 
61 static int can_modify_feature(struct btrfs_feature_attr *fa)
62 {
63 	int val = 0;
64 	u64 set, clear;
65 	switch (fa->feature_set) {
66 	case FEAT_COMPAT:
67 		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
68 		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
69 		break;
70 	case FEAT_COMPAT_RO:
71 		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
72 		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
73 		break;
74 	case FEAT_INCOMPAT:
75 		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
76 		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
77 		break;
78 	default:
79 		printk(KERN_WARNING "btrfs: sysfs: unknown feature set %d\n",
80 				fa->feature_set);
81 		return 0;
82 	}
83 
84 	if (set & fa->feature_bit)
85 		val |= 1;
86 	if (clear & fa->feature_bit)
87 		val |= 2;
88 
89 	return val;
90 }
91 
92 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
93 				       struct kobj_attribute *a, char *buf)
94 {
95 	int val = 0;
96 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
97 	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
98 	if (fs_info) {
99 		u64 features = get_features(fs_info, fa->feature_set);
100 		if (features & fa->feature_bit)
101 			val = 1;
102 	} else
103 		val = can_modify_feature(fa);
104 
105 	return snprintf(buf, PAGE_SIZE, "%d\n", val);
106 }
107 
108 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
109 					struct kobj_attribute *a,
110 					const char *buf, size_t count)
111 {
112 	struct btrfs_fs_info *fs_info;
113 	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
114 	struct btrfs_trans_handle *trans;
115 	u64 features, set, clear;
116 	unsigned long val;
117 	int ret;
118 
119 	fs_info = to_fs_info(kobj);
120 	if (!fs_info)
121 		return -EPERM;
122 
123 	ret = kstrtoul(skip_spaces(buf), 0, &val);
124 	if (ret)
125 		return ret;
126 
127 	if (fa->feature_set == FEAT_COMPAT) {
128 		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
129 		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
130 	} else if (fa->feature_set == FEAT_COMPAT_RO) {
131 		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
132 		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
133 	} else {
134 		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
135 		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
136 	}
137 
138 	features = get_features(fs_info, fa->feature_set);
139 
140 	/* Nothing to do */
141 	if ((val && (features & fa->feature_bit)) ||
142 	    (!val && !(features & fa->feature_bit)))
143 		return count;
144 
145 	if ((val && !(set & fa->feature_bit)) ||
146 	    (!val && !(clear & fa->feature_bit))) {
147 		btrfs_info(fs_info,
148 			"%sabling feature %s on mounted fs is not supported.",
149 			val ? "En" : "Dis", fa->kobj_attr.attr.name);
150 		return -EPERM;
151 	}
152 
153 	btrfs_info(fs_info, "%s %s feature flag",
154 		   val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
155 
156 	trans = btrfs_start_transaction(fs_info->fs_root, 0);
157 	if (IS_ERR(trans))
158 		return PTR_ERR(trans);
159 
160 	spin_lock(&fs_info->super_lock);
161 	features = get_features(fs_info, fa->feature_set);
162 	if (val)
163 		features |= fa->feature_bit;
164 	else
165 		features &= ~fa->feature_bit;
166 	set_features(fs_info, fa->feature_set, features);
167 	spin_unlock(&fs_info->super_lock);
168 
169 	ret = btrfs_commit_transaction(trans, fs_info->fs_root);
170 	if (ret)
171 		return ret;
172 
173 	return count;
174 }
175 
176 static umode_t btrfs_feature_visible(struct kobject *kobj,
177 				     struct attribute *attr, int unused)
178 {
179 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
180 	umode_t mode = attr->mode;
181 
182 	if (fs_info) {
183 		struct btrfs_feature_attr *fa;
184 		u64 features;
185 
186 		fa = attr_to_btrfs_feature_attr(attr);
187 		features = get_features(fs_info, fa->feature_set);
188 
189 		if (can_modify_feature(fa))
190 			mode |= S_IWUSR;
191 		else if (!(features & fa->feature_bit))
192 			mode = 0;
193 	}
194 
195 	return mode;
196 }
197 
198 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
199 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
200 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
201 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
202 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
203 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
204 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
205 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
206 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
207 
208 static struct attribute *btrfs_supported_feature_attrs[] = {
209 	BTRFS_FEAT_ATTR_PTR(mixed_backref),
210 	BTRFS_FEAT_ATTR_PTR(default_subvol),
211 	BTRFS_FEAT_ATTR_PTR(mixed_groups),
212 	BTRFS_FEAT_ATTR_PTR(compress_lzo),
213 	BTRFS_FEAT_ATTR_PTR(big_metadata),
214 	BTRFS_FEAT_ATTR_PTR(extended_iref),
215 	BTRFS_FEAT_ATTR_PTR(raid56),
216 	BTRFS_FEAT_ATTR_PTR(skinny_metadata),
217 	BTRFS_FEAT_ATTR_PTR(no_holes),
218 	NULL
219 };
220 
221 static const struct attribute_group btrfs_feature_attr_group = {
222 	.name = "features",
223 	.is_visible = btrfs_feature_visible,
224 	.attrs = btrfs_supported_feature_attrs,
225 };
226 
227 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
228 {
229 	u64 val;
230 	if (lock)
231 		spin_lock(lock);
232 	val = *value_ptr;
233 	if (lock)
234 		spin_unlock(lock);
235 	return snprintf(buf, PAGE_SIZE, "%llu\n", val);
236 }
237 
238 static ssize_t global_rsv_size_show(struct kobject *kobj,
239 				    struct kobj_attribute *ka, char *buf)
240 {
241 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
242 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
243 	return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
244 }
245 BTRFS_ATTR(global_rsv_size, global_rsv_size_show);
246 
247 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
248 					struct kobj_attribute *a, char *buf)
249 {
250 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
251 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
252 	return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
253 }
254 BTRFS_ATTR(global_rsv_reserved, global_rsv_reserved_show);
255 
256 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
257 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
258 
259 static ssize_t raid_bytes_show(struct kobject *kobj,
260 			       struct kobj_attribute *attr, char *buf);
261 BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
262 BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
263 
264 static ssize_t raid_bytes_show(struct kobject *kobj,
265 			       struct kobj_attribute *attr, char *buf)
266 
267 {
268 	struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
269 	struct btrfs_block_group_cache *block_group;
270 	int index = to_raid_kobj(kobj)->raid_type;
271 	u64 val = 0;
272 
273 	down_read(&sinfo->groups_sem);
274 	list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
275 		if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
276 			val += block_group->key.offset;
277 		else
278 			val += btrfs_block_group_used(&block_group->item);
279 	}
280 	up_read(&sinfo->groups_sem);
281 	return snprintf(buf, PAGE_SIZE, "%llu\n", val);
282 }
283 
284 static struct attribute *raid_attributes[] = {
285 	BTRFS_RAID_ATTR_PTR(total_bytes),
286 	BTRFS_RAID_ATTR_PTR(used_bytes),
287 	NULL
288 };
289 
290 static void release_raid_kobj(struct kobject *kobj)
291 {
292 	kfree(to_raid_kobj(kobj));
293 }
294 
295 struct kobj_type btrfs_raid_ktype = {
296 	.sysfs_ops = &kobj_sysfs_ops,
297 	.release = release_raid_kobj,
298 	.default_attrs = raid_attributes,
299 };
300 
301 #define SPACE_INFO_ATTR(field)						\
302 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,	\
303 					     struct kobj_attribute *a,	\
304 					     char *buf)			\
305 {									\
306 	struct btrfs_space_info *sinfo = to_space_info(kobj);		\
307 	return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);	\
308 }									\
309 BTRFS_ATTR(field, btrfs_space_info_show_##field)
310 
311 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
312 						       struct kobj_attribute *a,
313 						       char *buf)
314 {
315 	struct btrfs_space_info *sinfo = to_space_info(kobj);
316 	s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
317 	return snprintf(buf, PAGE_SIZE, "%lld\n", val);
318 }
319 
320 SPACE_INFO_ATTR(flags);
321 SPACE_INFO_ATTR(total_bytes);
322 SPACE_INFO_ATTR(bytes_used);
323 SPACE_INFO_ATTR(bytes_pinned);
324 SPACE_INFO_ATTR(bytes_reserved);
325 SPACE_INFO_ATTR(bytes_may_use);
326 SPACE_INFO_ATTR(disk_used);
327 SPACE_INFO_ATTR(disk_total);
328 BTRFS_ATTR(total_bytes_pinned, btrfs_space_info_show_total_bytes_pinned);
329 
330 static struct attribute *space_info_attrs[] = {
331 	BTRFS_ATTR_PTR(flags),
332 	BTRFS_ATTR_PTR(total_bytes),
333 	BTRFS_ATTR_PTR(bytes_used),
334 	BTRFS_ATTR_PTR(bytes_pinned),
335 	BTRFS_ATTR_PTR(bytes_reserved),
336 	BTRFS_ATTR_PTR(bytes_may_use),
337 	BTRFS_ATTR_PTR(disk_used),
338 	BTRFS_ATTR_PTR(disk_total),
339 	BTRFS_ATTR_PTR(total_bytes_pinned),
340 	NULL,
341 };
342 
343 static void space_info_release(struct kobject *kobj)
344 {
345 	struct btrfs_space_info *sinfo = to_space_info(kobj);
346 	percpu_counter_destroy(&sinfo->total_bytes_pinned);
347 	kfree(sinfo);
348 }
349 
350 struct kobj_type space_info_ktype = {
351 	.sysfs_ops = &kobj_sysfs_ops,
352 	.release = space_info_release,
353 	.default_attrs = space_info_attrs,
354 };
355 
356 static const struct attribute *allocation_attrs[] = {
357 	BTRFS_ATTR_PTR(global_rsv_reserved),
358 	BTRFS_ATTR_PTR(global_rsv_size),
359 	NULL,
360 };
361 
362 static ssize_t btrfs_label_show(struct kobject *kobj,
363 				struct kobj_attribute *a, char *buf)
364 {
365 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
366 	char *label = fs_info->super_copy->label;
367 	return snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
368 }
369 
370 static ssize_t btrfs_label_store(struct kobject *kobj,
371 				 struct kobj_attribute *a,
372 				 const char *buf, size_t len)
373 {
374 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
375 	struct btrfs_trans_handle *trans;
376 	struct btrfs_root *root = fs_info->fs_root;
377 	int ret;
378 	size_t p_len;
379 
380 	if (fs_info->sb->s_flags & MS_RDONLY)
381 		return -EROFS;
382 
383 	/*
384 	 * p_len is the len until the first occurrence of either
385 	 * '\n' or '\0'
386 	 */
387 	p_len = strcspn(buf, "\n");
388 
389 	if (p_len >= BTRFS_LABEL_SIZE)
390 		return -EINVAL;
391 
392 	trans = btrfs_start_transaction(root, 0);
393 	if (IS_ERR(trans))
394 		return PTR_ERR(trans);
395 
396 	spin_lock(&root->fs_info->super_lock);
397 	memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
398 	memcpy(fs_info->super_copy->label, buf, p_len);
399 	spin_unlock(&root->fs_info->super_lock);
400 	ret = btrfs_commit_transaction(trans, root);
401 
402 	if (!ret)
403 		return len;
404 
405 	return ret;
406 }
407 BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);
408 
409 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
410 				struct kobj_attribute *a, char *buf)
411 {
412 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
413 
414 	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
415 }
416 
417 BTRFS_ATTR(nodesize, btrfs_nodesize_show);
418 
419 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
420 				struct kobj_attribute *a, char *buf)
421 {
422 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
423 
424 	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
425 }
426 
427 BTRFS_ATTR(sectorsize, btrfs_sectorsize_show);
428 
429 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
430 				struct kobj_attribute *a, char *buf)
431 {
432 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
433 
434 	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
435 }
436 
437 BTRFS_ATTR(clone_alignment, btrfs_clone_alignment_show);
438 
439 static struct attribute *btrfs_attrs[] = {
440 	BTRFS_ATTR_PTR(label),
441 	BTRFS_ATTR_PTR(nodesize),
442 	BTRFS_ATTR_PTR(sectorsize),
443 	BTRFS_ATTR_PTR(clone_alignment),
444 	NULL,
445 };
446 
447 static void btrfs_release_super_kobj(struct kobject *kobj)
448 {
449 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
450 	complete(&fs_info->kobj_unregister);
451 }
452 
453 static struct kobj_type btrfs_ktype = {
454 	.sysfs_ops	= &kobj_sysfs_ops,
455 	.release	= btrfs_release_super_kobj,
456 	.default_attrs	= btrfs_attrs,
457 };
458 
459 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
460 {
461 	if (kobj->ktype != &btrfs_ktype)
462 		return NULL;
463 	return container_of(kobj, struct btrfs_fs_info, super_kobj);
464 }
465 
466 #define NUM_FEATURE_BITS 64
467 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
468 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
469 
470 static u64 supported_feature_masks[3] = {
471 	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
472 	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
473 	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
474 };
475 
476 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
477 {
478 	int set;
479 
480 	for (set = 0; set < FEAT_MAX; set++) {
481 		int i;
482 		struct attribute *attrs[2];
483 		struct attribute_group agroup = {
484 			.name = "features",
485 			.attrs = attrs,
486 		};
487 		u64 features = get_features(fs_info, set);
488 		features &= ~supported_feature_masks[set];
489 
490 		if (!features)
491 			continue;
492 
493 		attrs[1] = NULL;
494 		for (i = 0; i < NUM_FEATURE_BITS; i++) {
495 			struct btrfs_feature_attr *fa;
496 
497 			if (!(features & (1ULL << i)))
498 				continue;
499 
500 			fa = &btrfs_feature_attrs[set][i];
501 			attrs[0] = &fa->kobj_attr.attr;
502 			if (add) {
503 				int ret;
504 				ret = sysfs_merge_group(&fs_info->super_kobj,
505 							&agroup);
506 				if (ret)
507 					return ret;
508 			} else
509 				sysfs_unmerge_group(&fs_info->super_kobj,
510 						    &agroup);
511 		}
512 
513 	}
514 	return 0;
515 }
516 
517 static void __btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
518 {
519 	kobject_del(&fs_info->super_kobj);
520 	kobject_put(&fs_info->super_kobj);
521 	wait_for_completion(&fs_info->kobj_unregister);
522 }
523 
524 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
525 {
526 	if (fs_info->space_info_kobj) {
527 		sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
528 		kobject_del(fs_info->space_info_kobj);
529 		kobject_put(fs_info->space_info_kobj);
530 	}
531 	kobject_del(fs_info->device_dir_kobj);
532 	kobject_put(fs_info->device_dir_kobj);
533 	addrm_unknown_feature_attrs(fs_info, false);
534 	sysfs_remove_group(&fs_info->super_kobj, &btrfs_feature_attr_group);
535 	__btrfs_sysfs_remove_one(fs_info);
536 }
537 
538 const char * const btrfs_feature_set_names[3] = {
539 	[FEAT_COMPAT]	 = "compat",
540 	[FEAT_COMPAT_RO] = "compat_ro",
541 	[FEAT_INCOMPAT]	 = "incompat",
542 };
543 
544 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
545 {
546 	size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
547 	int len = 0;
548 	int i;
549 	char *str;
550 
551 	str = kmalloc(bufsize, GFP_KERNEL);
552 	if (!str)
553 		return str;
554 
555 	for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
556 		const char *name;
557 
558 		if (!(flags & (1ULL << i)))
559 			continue;
560 
561 		name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
562 		len += snprintf(str + len, bufsize - len, "%s%s",
563 				len ? "," : "", name);
564 	}
565 
566 	return str;
567 }
568 
569 static void init_feature_attrs(void)
570 {
571 	struct btrfs_feature_attr *fa;
572 	int set, i;
573 
574 	BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
575 		     ARRAY_SIZE(btrfs_feature_attrs));
576 	BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
577 		     ARRAY_SIZE(btrfs_feature_attrs[0]));
578 
579 	memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
580 	memset(btrfs_unknown_feature_names, 0,
581 	       sizeof(btrfs_unknown_feature_names));
582 
583 	for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
584 		struct btrfs_feature_attr *sfa;
585 		struct attribute *a = btrfs_supported_feature_attrs[i];
586 		int bit;
587 		sfa = attr_to_btrfs_feature_attr(a);
588 		bit = ilog2(sfa->feature_bit);
589 		fa = &btrfs_feature_attrs[sfa->feature_set][bit];
590 
591 		fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
592 	}
593 
594 	for (set = 0; set < FEAT_MAX; set++) {
595 		for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
596 			char *name = btrfs_unknown_feature_names[set][i];
597 			fa = &btrfs_feature_attrs[set][i];
598 
599 			if (fa->kobj_attr.attr.name)
600 				continue;
601 
602 			snprintf(name, 13, "%s:%u",
603 				 btrfs_feature_set_names[set], i);
604 
605 			fa->kobj_attr.attr.name = name;
606 			fa->kobj_attr.attr.mode = S_IRUGO;
607 			fa->feature_set = set;
608 			fa->feature_bit = 1ULL << i;
609 		}
610 	}
611 }
612 
613 int btrfs_kobj_rm_device(struct btrfs_fs_info *fs_info,
614 		struct btrfs_device *one_device)
615 {
616 	struct hd_struct *disk;
617 	struct kobject *disk_kobj;
618 
619 	if (!fs_info->device_dir_kobj)
620 		return -EINVAL;
621 
622 	if (one_device && one_device->bdev) {
623 		disk = one_device->bdev->bd_part;
624 		disk_kobj = &part_to_dev(disk)->kobj;
625 
626 		sysfs_remove_link(fs_info->device_dir_kobj,
627 						disk_kobj->name);
628 	}
629 
630 	return 0;
631 }
632 
633 int btrfs_kobj_add_device(struct btrfs_fs_info *fs_info,
634 		struct btrfs_device *one_device)
635 {
636 	int error = 0;
637 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
638 	struct btrfs_device *dev;
639 
640 	if (!fs_info->device_dir_kobj)
641 		fs_info->device_dir_kobj = kobject_create_and_add("devices",
642 						&fs_info->super_kobj);
643 
644 	if (!fs_info->device_dir_kobj)
645 		return -ENOMEM;
646 
647 	list_for_each_entry(dev, &fs_devices->devices, dev_list) {
648 		struct hd_struct *disk;
649 		struct kobject *disk_kobj;
650 
651 		if (!dev->bdev)
652 			continue;
653 
654 		if (one_device && one_device != dev)
655 			continue;
656 
657 		disk = dev->bdev->bd_part;
658 		disk_kobj = &part_to_dev(disk)->kobj;
659 
660 		error = sysfs_create_link(fs_info->device_dir_kobj,
661 					  disk_kobj, disk_kobj->name);
662 		if (error)
663 			break;
664 	}
665 
666 	return error;
667 }
668 
669 /* /sys/fs/btrfs/ entry */
670 static struct kset *btrfs_kset;
671 
672 /* /sys/kernel/debug/btrfs */
673 static struct dentry *btrfs_debugfs_root_dentry;
674 
675 /* Debugging tunables and exported data */
676 u64 btrfs_debugfs_test;
677 
678 int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
679 {
680 	int error;
681 
682 	init_completion(&fs_info->kobj_unregister);
683 	fs_info->super_kobj.kset = btrfs_kset;
684 	error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
685 				     "%pU", fs_info->fsid);
686 	if (error)
687 		return error;
688 
689 	error = sysfs_create_group(&fs_info->super_kobj,
690 				   &btrfs_feature_attr_group);
691 	if (error) {
692 		__btrfs_sysfs_remove_one(fs_info);
693 		return error;
694 	}
695 
696 	error = addrm_unknown_feature_attrs(fs_info, true);
697 	if (error)
698 		goto failure;
699 
700 	error = btrfs_kobj_add_device(fs_info, NULL);
701 	if (error)
702 		goto failure;
703 
704 	fs_info->space_info_kobj = kobject_create_and_add("allocation",
705 						  &fs_info->super_kobj);
706 	if (!fs_info->space_info_kobj) {
707 		error = -ENOMEM;
708 		goto failure;
709 	}
710 
711 	error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
712 	if (error)
713 		goto failure;
714 
715 	return 0;
716 failure:
717 	btrfs_sysfs_remove_one(fs_info);
718 	return error;
719 }
720 
721 static int btrfs_init_debugfs(void)
722 {
723 #ifdef CONFIG_DEBUG_FS
724 	btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
725 	if (!btrfs_debugfs_root_dentry)
726 		return -ENOMEM;
727 
728 	debugfs_create_u64("test", S_IRUGO | S_IWUGO, btrfs_debugfs_root_dentry,
729 			&btrfs_debugfs_test);
730 #endif
731 	return 0;
732 }
733 
734 int btrfs_init_sysfs(void)
735 {
736 	int ret;
737 
738 	btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
739 	if (!btrfs_kset)
740 		return -ENOMEM;
741 
742 	ret = btrfs_init_debugfs();
743 	if (ret)
744 		return ret;
745 
746 	init_feature_attrs();
747 	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
748 
749 	return ret;
750 }
751 
752 void btrfs_exit_sysfs(void)
753 {
754 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
755 	kset_unregister(btrfs_kset);
756 	debugfs_remove_recursive(btrfs_debugfs_root_dentry);
757 }
758 
759