xref: /linux/fs/btrfs/sysfs.c (revision a4ff64edf9edc8f05e2183610dc8306d3279c6ac)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2007 Oracle.  All rights reserved.
4  */
5 
6 #include <linux/sched.h>
7 #include <linux/sched/mm.h>
8 #include <linux/slab.h>
9 #include <linux/spinlock.h>
10 #include <linux/completion.h>
11 #include <linux/bug.h>
12 #include <linux/list.h>
13 #include <crypto/hash.h>
14 #include "messages.h"
15 #include "ctree.h"
16 #include "discard.h"
17 #include "disk-io.h"
18 #include "send.h"
19 #include "transaction.h"
20 #include "sysfs.h"
21 #include "volumes.h"
22 #include "space-info.h"
23 #include "block-group.h"
24 #include "qgroup.h"
25 #include "misc.h"
26 #include "fs.h"
27 #include "accessors.h"
28 
29 /*
30  * Structure name                       Path
31  * --------------------------------------------------------------------------
32  * btrfs_supported_static_feature_attrs /sys/fs/btrfs/features
33  * btrfs_supported_feature_attrs	/sys/fs/btrfs/features and
34  *					/sys/fs/btrfs/<uuid>/features
35  * btrfs_attrs				/sys/fs/btrfs/<uuid>
36  * devid_attrs				/sys/fs/btrfs/<uuid>/devinfo/<devid>
37  * allocation_attrs			/sys/fs/btrfs/<uuid>/allocation
38  * qgroup_attrs				/sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>
39  * space_info_attrs			/sys/fs/btrfs/<uuid>/allocation/<bg-type>
40  * raid_attrs				/sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>
41  * discard_attrs			/sys/fs/btrfs/<uuid>/discard
42  *
43  * When built with BTRFS_CONFIG_DEBUG:
44  *
45  * btrfs_debug_feature_attrs		/sys/fs/btrfs/debug
46  * btrfs_debug_mount_attrs		/sys/fs/btrfs/<uuid>/debug
47  */
48 
49 struct btrfs_feature_attr {
50 	struct kobj_attribute kobj_attr;
51 	enum btrfs_feature_set feature_set;
52 	u64 feature_bit;
53 };
54 
55 /* For raid type sysfs entries */
56 struct raid_kobject {
57 	u64 flags;
58 	struct kobject kobj;
59 };
60 
61 #define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)			\
62 {									\
63 	.attr	= { .name = __stringify(_name), .mode = _mode },	\
64 	.show	= _show,						\
65 	.store	= _store,						\
66 }
67 
68 #define BTRFS_ATTR_W(_prefix, _name, _store)			        \
69 	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
70 			__INIT_KOBJ_ATTR(_name, 0200, NULL, _store)
71 
72 #define BTRFS_ATTR_RW(_prefix, _name, _show, _store)			\
73 	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
74 			__INIT_KOBJ_ATTR(_name, 0644, _show, _store)
75 
76 #define BTRFS_ATTR(_prefix, _name, _show)				\
77 	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
78 			__INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
79 
80 #define BTRFS_ATTR_PTR(_prefix, _name)					\
81 	(&btrfs_attr_##_prefix##_##_name.attr)
82 
83 #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
84 static struct btrfs_feature_attr btrfs_attr_features_##_name = {	     \
85 	.kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,			     \
86 				      btrfs_feature_attr_show,		     \
87 				      btrfs_feature_attr_store),	     \
88 	.feature_set	= _feature_set,					     \
89 	.feature_bit	= _feature_prefix ##_## _feature_bit,		     \
90 }
91 #define BTRFS_FEAT_ATTR_PTR(_name)					     \
92 	(&btrfs_attr_features_##_name.kobj_attr.attr)
93 
94 #define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
95 	BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
96 #define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
97 	BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
98 #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
99 	BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)
100 
101 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
102 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
103 static struct kobject *get_btrfs_kobj(struct kobject *kobj);
104 
105 static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
106 {
107 	return container_of(a, struct btrfs_feature_attr, kobj_attr);
108 }
109 
110 static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
111 {
112 	return container_of(attr, struct kobj_attribute, attr);
113 }
114 
115 static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
116 		struct attribute *attr)
117 {
118 	return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
119 }
120 
121 static u64 get_features(struct btrfs_fs_info *fs_info,
122 			enum btrfs_feature_set set)
123 {
124 	struct btrfs_super_block *disk_super = fs_info->super_copy;
125 	if (set == FEAT_COMPAT)
126 		return btrfs_super_compat_flags(disk_super);
127 	else if (set == FEAT_COMPAT_RO)
128 		return btrfs_super_compat_ro_flags(disk_super);
129 	else
130 		return btrfs_super_incompat_flags(disk_super);
131 }
132 
133 static void set_features(struct btrfs_fs_info *fs_info,
134 			 enum btrfs_feature_set set, u64 features)
135 {
136 	struct btrfs_super_block *disk_super = fs_info->super_copy;
137 	if (set == FEAT_COMPAT)
138 		btrfs_set_super_compat_flags(disk_super, features);
139 	else if (set == FEAT_COMPAT_RO)
140 		btrfs_set_super_compat_ro_flags(disk_super, features);
141 	else
142 		btrfs_set_super_incompat_flags(disk_super, features);
143 }
144 
145 static int can_modify_feature(struct btrfs_feature_attr *fa)
146 {
147 	int val = 0;
148 	u64 set, clear;
149 	switch (fa->feature_set) {
150 	case FEAT_COMPAT:
151 		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
152 		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
153 		break;
154 	case FEAT_COMPAT_RO:
155 		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
156 		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
157 		break;
158 	case FEAT_INCOMPAT:
159 		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
160 		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
161 		break;
162 	default:
163 		pr_warn("btrfs: sysfs: unknown feature set %d\n",
164 				fa->feature_set);
165 		return 0;
166 	}
167 
168 	if (set & fa->feature_bit)
169 		val |= 1;
170 	if (clear & fa->feature_bit)
171 		val |= 2;
172 
173 	return val;
174 }
175 
176 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
177 				       struct kobj_attribute *a, char *buf)
178 {
179 	int val = 0;
180 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
181 	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
182 	if (fs_info) {
183 		u64 features = get_features(fs_info, fa->feature_set);
184 		if (features & fa->feature_bit)
185 			val = 1;
186 	} else
187 		val = can_modify_feature(fa);
188 
189 	return sysfs_emit(buf, "%d\n", val);
190 }
191 
192 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
193 					struct kobj_attribute *a,
194 					const char *buf, size_t count)
195 {
196 	struct btrfs_fs_info *fs_info;
197 	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
198 	u64 features, set, clear;
199 	unsigned long val;
200 	int ret;
201 
202 	fs_info = to_fs_info(kobj);
203 	if (!fs_info)
204 		return -EPERM;
205 
206 	if (sb_rdonly(fs_info->sb))
207 		return -EROFS;
208 
209 	ret = kstrtoul(skip_spaces(buf), 0, &val);
210 	if (ret)
211 		return ret;
212 
213 	if (fa->feature_set == FEAT_COMPAT) {
214 		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
215 		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
216 	} else if (fa->feature_set == FEAT_COMPAT_RO) {
217 		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
218 		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
219 	} else {
220 		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
221 		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
222 	}
223 
224 	features = get_features(fs_info, fa->feature_set);
225 
226 	/* Nothing to do */
227 	if ((val && (features & fa->feature_bit)) ||
228 	    (!val && !(features & fa->feature_bit)))
229 		return count;
230 
231 	if ((val && !(set & fa->feature_bit)) ||
232 	    (!val && !(clear & fa->feature_bit))) {
233 		btrfs_info(fs_info,
234 			"%sabling feature %s on mounted fs is not supported.",
235 			val ? "En" : "Dis", fa->kobj_attr.attr.name);
236 		return -EPERM;
237 	}
238 
239 	btrfs_info(fs_info, "%s %s feature flag",
240 		   val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
241 
242 	spin_lock(&fs_info->super_lock);
243 	features = get_features(fs_info, fa->feature_set);
244 	if (val)
245 		features |= fa->feature_bit;
246 	else
247 		features &= ~fa->feature_bit;
248 	set_features(fs_info, fa->feature_set, features);
249 	spin_unlock(&fs_info->super_lock);
250 
251 	/*
252 	 * We don't want to do full transaction commit from inside sysfs
253 	 */
254 	set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
255 	wake_up_process(fs_info->transaction_kthread);
256 
257 	return count;
258 }
259 
260 static umode_t btrfs_feature_visible(struct kobject *kobj,
261 				     struct attribute *attr, int unused)
262 {
263 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
264 	umode_t mode = attr->mode;
265 
266 	if (fs_info) {
267 		struct btrfs_feature_attr *fa;
268 		u64 features;
269 
270 		fa = attr_to_btrfs_feature_attr(attr);
271 		features = get_features(fs_info, fa->feature_set);
272 
273 		if (can_modify_feature(fa))
274 			mode |= S_IWUSR;
275 		else if (!(features & fa->feature_bit))
276 			mode = 0;
277 	}
278 
279 	return mode;
280 }
281 
282 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
283 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
284 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
285 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
286 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
287 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
288 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
289 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
290 BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
291 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
292 BTRFS_FEAT_ATTR_COMPAT_RO(block_group_tree, BLOCK_GROUP_TREE);
293 BTRFS_FEAT_ATTR_INCOMPAT(raid1c34, RAID1C34);
294 BTRFS_FEAT_ATTR_INCOMPAT(simple_quota, SIMPLE_QUOTA);
295 #ifdef CONFIG_BLK_DEV_ZONED
296 BTRFS_FEAT_ATTR_INCOMPAT(zoned, ZONED);
297 #endif
298 #ifdef CONFIG_BTRFS_DEBUG
299 /* Remove once support for extent tree v2 is feature complete */
300 BTRFS_FEAT_ATTR_INCOMPAT(extent_tree_v2, EXTENT_TREE_V2);
301 /* Remove once support for raid stripe tree is feature complete. */
302 BTRFS_FEAT_ATTR_INCOMPAT(raid_stripe_tree, RAID_STRIPE_TREE);
303 #endif
304 #ifdef CONFIG_FS_VERITY
305 BTRFS_FEAT_ATTR_COMPAT_RO(verity, VERITY);
306 #endif
307 
308 /*
309  * Features which depend on feature bits and may differ between each fs.
310  *
311  * /sys/fs/btrfs/features      - all available features implemented by this version
312  * /sys/fs/btrfs/UUID/features - features of the fs which are enabled or
313  *                               can be changed on a mounted filesystem.
314  */
315 static struct attribute *btrfs_supported_feature_attrs[] = {
316 	BTRFS_FEAT_ATTR_PTR(default_subvol),
317 	BTRFS_FEAT_ATTR_PTR(mixed_groups),
318 	BTRFS_FEAT_ATTR_PTR(compress_lzo),
319 	BTRFS_FEAT_ATTR_PTR(compress_zstd),
320 	BTRFS_FEAT_ATTR_PTR(extended_iref),
321 	BTRFS_FEAT_ATTR_PTR(raid56),
322 	BTRFS_FEAT_ATTR_PTR(skinny_metadata),
323 	BTRFS_FEAT_ATTR_PTR(no_holes),
324 	BTRFS_FEAT_ATTR_PTR(metadata_uuid),
325 	BTRFS_FEAT_ATTR_PTR(free_space_tree),
326 	BTRFS_FEAT_ATTR_PTR(raid1c34),
327 	BTRFS_FEAT_ATTR_PTR(block_group_tree),
328 	BTRFS_FEAT_ATTR_PTR(simple_quota),
329 #ifdef CONFIG_BLK_DEV_ZONED
330 	BTRFS_FEAT_ATTR_PTR(zoned),
331 #endif
332 #ifdef CONFIG_BTRFS_DEBUG
333 	BTRFS_FEAT_ATTR_PTR(extent_tree_v2),
334 	BTRFS_FEAT_ATTR_PTR(raid_stripe_tree),
335 #endif
336 #ifdef CONFIG_FS_VERITY
337 	BTRFS_FEAT_ATTR_PTR(verity),
338 #endif
339 	NULL
340 };
341 
342 static const struct attribute_group btrfs_feature_attr_group = {
343 	.name = "features",
344 	.is_visible = btrfs_feature_visible,
345 	.attrs = btrfs_supported_feature_attrs,
346 };
347 
348 static ssize_t rmdir_subvol_show(struct kobject *kobj,
349 				 struct kobj_attribute *ka, char *buf)
350 {
351 	return sysfs_emit(buf, "0\n");
352 }
353 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
354 
355 static ssize_t supported_checksums_show(struct kobject *kobj,
356 					struct kobj_attribute *a, char *buf)
357 {
358 	ssize_t ret = 0;
359 	int i;
360 
361 	for (i = 0; i < btrfs_get_num_csums(); i++) {
362 		/*
363 		 * This "trick" only works as long as 'enum btrfs_csum_type' has
364 		 * no holes in it
365 		 */
366 		ret += sysfs_emit_at(buf, ret, "%s%s", (i == 0 ? "" : " "),
367 				     btrfs_super_csum_name(i));
368 
369 	}
370 
371 	ret += sysfs_emit_at(buf, ret, "\n");
372 	return ret;
373 }
374 BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);
375 
376 static ssize_t send_stream_version_show(struct kobject *kobj,
377 					struct kobj_attribute *ka, char *buf)
378 {
379 	return sysfs_emit(buf, "%d\n", BTRFS_SEND_STREAM_VERSION);
380 }
381 BTRFS_ATTR(static_feature, send_stream_version, send_stream_version_show);
382 
383 static const char *rescue_opts[] = {
384 	"usebackuproot",
385 	"nologreplay",
386 	"ignorebadroots",
387 	"ignoredatacsums",
388 	"all",
389 };
390 
391 static ssize_t supported_rescue_options_show(struct kobject *kobj,
392 					     struct kobj_attribute *a,
393 					     char *buf)
394 {
395 	ssize_t ret = 0;
396 	int i;
397 
398 	for (i = 0; i < ARRAY_SIZE(rescue_opts); i++)
399 		ret += sysfs_emit_at(buf, ret, "%s%s", (i ? " " : ""), rescue_opts[i]);
400 	ret += sysfs_emit_at(buf, ret, "\n");
401 	return ret;
402 }
403 BTRFS_ATTR(static_feature, supported_rescue_options,
404 	   supported_rescue_options_show);
405 
406 static ssize_t supported_sectorsizes_show(struct kobject *kobj,
407 					  struct kobj_attribute *a,
408 					  char *buf)
409 {
410 	ssize_t ret = 0;
411 
412 	/* An artificial limit to only support 4K and PAGE_SIZE */
413 	if (PAGE_SIZE > SZ_4K)
414 		ret += sysfs_emit_at(buf, ret, "%u ", SZ_4K);
415 	ret += sysfs_emit_at(buf, ret, "%lu\n", PAGE_SIZE);
416 
417 	return ret;
418 }
419 BTRFS_ATTR(static_feature, supported_sectorsizes,
420 	   supported_sectorsizes_show);
421 
422 static ssize_t acl_show(struct kobject *kobj, struct kobj_attribute *a, char *buf)
423 {
424 	return sysfs_emit(buf, "%d\n", !!IS_ENABLED(CONFIG_BTRFS_FS_POSIX_ACL));
425 }
426 BTRFS_ATTR(static_feature, acl, acl_show);
427 
428 static ssize_t temp_fsid_supported_show(struct kobject *kobj,
429 					struct kobj_attribute *a, char *buf)
430 {
431 	return sysfs_emit(buf, "0\n");
432 }
433 BTRFS_ATTR(static_feature, temp_fsid, temp_fsid_supported_show);
434 
435 /*
436  * Features which only depend on kernel version.
437  *
438  * These are listed in /sys/fs/btrfs/features along with
439  * btrfs_supported_feature_attrs.
440  */
441 static struct attribute *btrfs_supported_static_feature_attrs[] = {
442 	BTRFS_ATTR_PTR(static_feature, acl),
443 	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
444 	BTRFS_ATTR_PTR(static_feature, supported_checksums),
445 	BTRFS_ATTR_PTR(static_feature, send_stream_version),
446 	BTRFS_ATTR_PTR(static_feature, supported_rescue_options),
447 	BTRFS_ATTR_PTR(static_feature, supported_sectorsizes),
448 	BTRFS_ATTR_PTR(static_feature, temp_fsid),
449 	NULL
450 };
451 
452 static const struct attribute_group btrfs_static_feature_attr_group = {
453 	.name = "features",
454 	.attrs = btrfs_supported_static_feature_attrs,
455 };
456 
457 /*
458  * Discard statistics and tunables
459  */
460 #define discard_to_fs_info(_kobj)	to_fs_info(get_btrfs_kobj(_kobj))
461 
462 static ssize_t btrfs_discardable_bytes_show(struct kobject *kobj,
463 					    struct kobj_attribute *a,
464 					    char *buf)
465 {
466 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
467 
468 	return sysfs_emit(buf, "%lld\n",
469 			atomic64_read(&fs_info->discard_ctl.discardable_bytes));
470 }
471 BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
472 
473 static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
474 					      struct kobj_attribute *a,
475 					      char *buf)
476 {
477 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
478 
479 	return sysfs_emit(buf, "%d\n",
480 			atomic_read(&fs_info->discard_ctl.discardable_extents));
481 }
482 BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
483 
484 static ssize_t btrfs_discard_bitmap_bytes_show(struct kobject *kobj,
485 					       struct kobj_attribute *a,
486 					       char *buf)
487 {
488 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
489 
490 	return sysfs_emit(buf, "%llu\n",
491 			  fs_info->discard_ctl.discard_bitmap_bytes);
492 }
493 BTRFS_ATTR(discard, discard_bitmap_bytes, btrfs_discard_bitmap_bytes_show);
494 
495 static ssize_t btrfs_discard_bytes_saved_show(struct kobject *kobj,
496 					      struct kobj_attribute *a,
497 					      char *buf)
498 {
499 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
500 
501 	return sysfs_emit(buf, "%lld\n",
502 		atomic64_read(&fs_info->discard_ctl.discard_bytes_saved));
503 }
504 BTRFS_ATTR(discard, discard_bytes_saved, btrfs_discard_bytes_saved_show);
505 
506 static ssize_t btrfs_discard_extent_bytes_show(struct kobject *kobj,
507 					       struct kobj_attribute *a,
508 					       char *buf)
509 {
510 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
511 
512 	return sysfs_emit(buf, "%llu\n",
513 			  fs_info->discard_ctl.discard_extent_bytes);
514 }
515 BTRFS_ATTR(discard, discard_extent_bytes, btrfs_discard_extent_bytes_show);
516 
517 static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
518 					     struct kobj_attribute *a,
519 					     char *buf)
520 {
521 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
522 
523 	return sysfs_emit(buf, "%u\n",
524 			  READ_ONCE(fs_info->discard_ctl.iops_limit));
525 }
526 
527 static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
528 					      struct kobj_attribute *a,
529 					      const char *buf, size_t len)
530 {
531 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
532 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
533 	u32 iops_limit;
534 	int ret;
535 
536 	ret = kstrtou32(buf, 10, &iops_limit);
537 	if (ret)
538 		return -EINVAL;
539 
540 	WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
541 	btrfs_discard_calc_delay(discard_ctl);
542 	btrfs_discard_schedule_work(discard_ctl, true);
543 	return len;
544 }
545 BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
546 	      btrfs_discard_iops_limit_store);
547 
548 static ssize_t btrfs_discard_kbps_limit_show(struct kobject *kobj,
549 					     struct kobj_attribute *a,
550 					     char *buf)
551 {
552 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
553 
554 	return sysfs_emit(buf, "%u\n",
555 			  READ_ONCE(fs_info->discard_ctl.kbps_limit));
556 }
557 
558 static ssize_t btrfs_discard_kbps_limit_store(struct kobject *kobj,
559 					      struct kobj_attribute *a,
560 					      const char *buf, size_t len)
561 {
562 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
563 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
564 	u32 kbps_limit;
565 	int ret;
566 
567 	ret = kstrtou32(buf, 10, &kbps_limit);
568 	if (ret)
569 		return -EINVAL;
570 
571 	WRITE_ONCE(discard_ctl->kbps_limit, kbps_limit);
572 	btrfs_discard_schedule_work(discard_ctl, true);
573 	return len;
574 }
575 BTRFS_ATTR_RW(discard, kbps_limit, btrfs_discard_kbps_limit_show,
576 	      btrfs_discard_kbps_limit_store);
577 
578 static ssize_t btrfs_discard_max_discard_size_show(struct kobject *kobj,
579 						   struct kobj_attribute *a,
580 						   char *buf)
581 {
582 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
583 
584 	return sysfs_emit(buf, "%llu\n",
585 			  READ_ONCE(fs_info->discard_ctl.max_discard_size));
586 }
587 
588 static ssize_t btrfs_discard_max_discard_size_store(struct kobject *kobj,
589 						    struct kobj_attribute *a,
590 						    const char *buf, size_t len)
591 {
592 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
593 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
594 	u64 max_discard_size;
595 	int ret;
596 
597 	ret = kstrtou64(buf, 10, &max_discard_size);
598 	if (ret)
599 		return -EINVAL;
600 
601 	WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);
602 
603 	return len;
604 }
605 BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
606 	      btrfs_discard_max_discard_size_store);
607 
608 /*
609  * Per-filesystem stats for discard (when mounted with discard=async).
610  *
611  * Path: /sys/fs/btrfs/<uuid>/discard/
612  */
613 static const struct attribute *discard_attrs[] = {
614 	BTRFS_ATTR_PTR(discard, discardable_bytes),
615 	BTRFS_ATTR_PTR(discard, discardable_extents),
616 	BTRFS_ATTR_PTR(discard, discard_bitmap_bytes),
617 	BTRFS_ATTR_PTR(discard, discard_bytes_saved),
618 	BTRFS_ATTR_PTR(discard, discard_extent_bytes),
619 	BTRFS_ATTR_PTR(discard, iops_limit),
620 	BTRFS_ATTR_PTR(discard, kbps_limit),
621 	BTRFS_ATTR_PTR(discard, max_discard_size),
622 	NULL,
623 };
624 
625 #ifdef CONFIG_BTRFS_DEBUG
626 
627 /*
628  * Per-filesystem runtime debugging exported via sysfs.
629  *
630  * Path: /sys/fs/btrfs/UUID/debug/
631  */
632 static const struct attribute *btrfs_debug_mount_attrs[] = {
633 	NULL,
634 };
635 
636 /*
637  * Runtime debugging exported via sysfs, applies to all mounted filesystems.
638  *
639  * Path: /sys/fs/btrfs/debug
640  */
641 static struct attribute *btrfs_debug_feature_attrs[] = {
642 	NULL
643 };
644 
645 static const struct attribute_group btrfs_debug_feature_attr_group = {
646 	.name = "debug",
647 	.attrs = btrfs_debug_feature_attrs,
648 };
649 
650 #endif
651 
652 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
653 {
654 	u64 val;
655 	if (lock)
656 		spin_lock(lock);
657 	val = *value_ptr;
658 	if (lock)
659 		spin_unlock(lock);
660 	return sysfs_emit(buf, "%llu\n", val);
661 }
662 
663 static ssize_t global_rsv_size_show(struct kobject *kobj,
664 				    struct kobj_attribute *ka, char *buf)
665 {
666 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
667 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
668 	return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
669 }
670 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
671 
672 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
673 					struct kobj_attribute *a, char *buf)
674 {
675 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
676 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
677 	return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
678 }
679 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
680 
681 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
682 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
683 
684 static ssize_t raid_bytes_show(struct kobject *kobj,
685 			       struct kobj_attribute *attr, char *buf);
686 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
687 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
688 
689 static ssize_t raid_bytes_show(struct kobject *kobj,
690 			       struct kobj_attribute *attr, char *buf)
691 
692 {
693 	struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
694 	struct btrfs_block_group *block_group;
695 	int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
696 	u64 val = 0;
697 
698 	down_read(&sinfo->groups_sem);
699 	list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
700 		if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
701 			val += block_group->length;
702 		else
703 			val += block_group->used;
704 	}
705 	up_read(&sinfo->groups_sem);
706 	return sysfs_emit(buf, "%llu\n", val);
707 }
708 
709 /*
710  * Allocation information about block group profiles.
711  *
712  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>/
713  */
714 static struct attribute *raid_attrs[] = {
715 	BTRFS_ATTR_PTR(raid, total_bytes),
716 	BTRFS_ATTR_PTR(raid, used_bytes),
717 	NULL
718 };
719 ATTRIBUTE_GROUPS(raid);
720 
721 static void release_raid_kobj(struct kobject *kobj)
722 {
723 	kfree(to_raid_kobj(kobj));
724 }
725 
726 static const struct kobj_type btrfs_raid_ktype = {
727 	.sysfs_ops = &kobj_sysfs_ops,
728 	.release = release_raid_kobj,
729 	.default_groups = raid_groups,
730 };
731 
732 #define SPACE_INFO_ATTR(field)						\
733 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,	\
734 					     struct kobj_attribute *a,	\
735 					     char *buf)			\
736 {									\
737 	struct btrfs_space_info *sinfo = to_space_info(kobj);		\
738 	return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);	\
739 }									\
740 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
741 
742 static ssize_t btrfs_chunk_size_show(struct kobject *kobj,
743 				     struct kobj_attribute *a, char *buf)
744 {
745 	struct btrfs_space_info *sinfo = to_space_info(kobj);
746 
747 	return sysfs_emit(buf, "%llu\n", READ_ONCE(sinfo->chunk_size));
748 }
749 
750 /*
751  * Store new chunk size in space info. Can be called on a read-only filesystem.
752  *
753  * If the new chunk size value is larger than 10% of free space it is reduced
754  * to match that limit. Alignment must be to 256M and the system chunk size
755  * cannot be set.
756  */
757 static ssize_t btrfs_chunk_size_store(struct kobject *kobj,
758 				      struct kobj_attribute *a,
759 				      const char *buf, size_t len)
760 {
761 	struct btrfs_space_info *space_info = to_space_info(kobj);
762 	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
763 	char *retptr;
764 	u64 val;
765 
766 	if (!capable(CAP_SYS_ADMIN))
767 		return -EPERM;
768 
769 	if (!fs_info->fs_devices)
770 		return -EINVAL;
771 
772 	if (btrfs_is_zoned(fs_info))
773 		return -EINVAL;
774 
775 	/* System block type must not be changed. */
776 	if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
777 		return -EPERM;
778 
779 	val = memparse(buf, &retptr);
780 	/* There could be trailing '\n', also catch any typos after the value */
781 	retptr = skip_spaces(retptr);
782 	if (*retptr != 0 || val == 0)
783 		return -EINVAL;
784 
785 	val = min(val, BTRFS_MAX_DATA_CHUNK_SIZE);
786 
787 	/* Limit stripe size to 10% of available space. */
788 	val = min(mult_perc(fs_info->fs_devices->total_rw_bytes, 10), val);
789 
790 	/* Must be multiple of 256M. */
791 	val &= ~((u64)SZ_256M - 1);
792 
793 	/* Must be at least 256M. */
794 	if (val < SZ_256M)
795 		return -EINVAL;
796 
797 	btrfs_update_space_info_chunk_size(space_info, val);
798 
799 	return len;
800 }
801 
802 static ssize_t btrfs_size_classes_show(struct kobject *kobj,
803 				       struct kobj_attribute *a, char *buf)
804 {
805 	struct btrfs_space_info *sinfo = to_space_info(kobj);
806 	struct btrfs_block_group *bg;
807 	u32 none = 0;
808 	u32 small = 0;
809 	u32 medium = 0;
810 	u32 large = 0;
811 
812 	for (int i = 0; i < BTRFS_NR_RAID_TYPES; ++i) {
813 		down_read(&sinfo->groups_sem);
814 		list_for_each_entry(bg, &sinfo->block_groups[i], list) {
815 			if (!btrfs_block_group_should_use_size_class(bg))
816 				continue;
817 			switch (bg->size_class) {
818 			case BTRFS_BG_SZ_NONE:
819 				none++;
820 				break;
821 			case BTRFS_BG_SZ_SMALL:
822 				small++;
823 				break;
824 			case BTRFS_BG_SZ_MEDIUM:
825 				medium++;
826 				break;
827 			case BTRFS_BG_SZ_LARGE:
828 				large++;
829 				break;
830 			}
831 		}
832 		up_read(&sinfo->groups_sem);
833 	}
834 	return sysfs_emit(buf, "none %u\n"
835 			       "small %u\n"
836 			       "medium %u\n"
837 			       "large %u\n",
838 			       none, small, medium, large);
839 }
840 
841 #ifdef CONFIG_BTRFS_DEBUG
842 /*
843  * Request chunk allocation with current chunk size.
844  */
845 static ssize_t btrfs_force_chunk_alloc_store(struct kobject *kobj,
846 					     struct kobj_attribute *a,
847 					     const char *buf, size_t len)
848 {
849 	struct btrfs_space_info *space_info = to_space_info(kobj);
850 	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
851 	struct btrfs_trans_handle *trans;
852 	bool val;
853 	int ret;
854 
855 	if (!capable(CAP_SYS_ADMIN))
856 		return -EPERM;
857 
858 	if (sb_rdonly(fs_info->sb))
859 		return -EROFS;
860 
861 	ret = kstrtobool(buf, &val);
862 	if (ret)
863 		return ret;
864 
865 	if (!val)
866 		return -EINVAL;
867 
868 	/*
869 	 * This is unsafe to be called from sysfs context and may cause
870 	 * unexpected problems.
871 	 */
872 	trans = btrfs_start_transaction(fs_info->tree_root, 0);
873 	if (IS_ERR(trans))
874 		return PTR_ERR(trans);
875 	ret = btrfs_force_chunk_alloc(trans, space_info->flags);
876 	btrfs_end_transaction(trans);
877 
878 	if (ret == 1)
879 		return len;
880 
881 	return -ENOSPC;
882 }
883 BTRFS_ATTR_W(space_info, force_chunk_alloc, btrfs_force_chunk_alloc_store);
884 
885 #endif
886 
887 SPACE_INFO_ATTR(flags);
888 SPACE_INFO_ATTR(total_bytes);
889 SPACE_INFO_ATTR(bytes_used);
890 SPACE_INFO_ATTR(bytes_pinned);
891 SPACE_INFO_ATTR(bytes_reserved);
892 SPACE_INFO_ATTR(bytes_may_use);
893 SPACE_INFO_ATTR(bytes_readonly);
894 SPACE_INFO_ATTR(bytes_zone_unusable);
895 SPACE_INFO_ATTR(disk_used);
896 SPACE_INFO_ATTR(disk_total);
897 BTRFS_ATTR_RW(space_info, chunk_size, btrfs_chunk_size_show, btrfs_chunk_size_store);
898 BTRFS_ATTR(space_info, size_classes, btrfs_size_classes_show);
899 
900 static ssize_t btrfs_sinfo_bg_reclaim_threshold_show(struct kobject *kobj,
901 						     struct kobj_attribute *a,
902 						     char *buf)
903 {
904 	struct btrfs_space_info *space_info = to_space_info(kobj);
905 
906 	return sysfs_emit(buf, "%d\n", READ_ONCE(space_info->bg_reclaim_threshold));
907 }
908 
909 static ssize_t btrfs_sinfo_bg_reclaim_threshold_store(struct kobject *kobj,
910 						      struct kobj_attribute *a,
911 						      const char *buf, size_t len)
912 {
913 	struct btrfs_space_info *space_info = to_space_info(kobj);
914 	int thresh;
915 	int ret;
916 
917 	ret = kstrtoint(buf, 10, &thresh);
918 	if (ret)
919 		return ret;
920 
921 	if (thresh < 0 || thresh > 100)
922 		return -EINVAL;
923 
924 	WRITE_ONCE(space_info->bg_reclaim_threshold, thresh);
925 
926 	return len;
927 }
928 
929 BTRFS_ATTR_RW(space_info, bg_reclaim_threshold,
930 	      btrfs_sinfo_bg_reclaim_threshold_show,
931 	      btrfs_sinfo_bg_reclaim_threshold_store);
932 
933 /*
934  * Allocation information about block group types.
935  *
936  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/
937  */
938 static struct attribute *space_info_attrs[] = {
939 	BTRFS_ATTR_PTR(space_info, flags),
940 	BTRFS_ATTR_PTR(space_info, total_bytes),
941 	BTRFS_ATTR_PTR(space_info, bytes_used),
942 	BTRFS_ATTR_PTR(space_info, bytes_pinned),
943 	BTRFS_ATTR_PTR(space_info, bytes_reserved),
944 	BTRFS_ATTR_PTR(space_info, bytes_may_use),
945 	BTRFS_ATTR_PTR(space_info, bytes_readonly),
946 	BTRFS_ATTR_PTR(space_info, bytes_zone_unusable),
947 	BTRFS_ATTR_PTR(space_info, disk_used),
948 	BTRFS_ATTR_PTR(space_info, disk_total),
949 	BTRFS_ATTR_PTR(space_info, bg_reclaim_threshold),
950 	BTRFS_ATTR_PTR(space_info, chunk_size),
951 	BTRFS_ATTR_PTR(space_info, size_classes),
952 #ifdef CONFIG_BTRFS_DEBUG
953 	BTRFS_ATTR_PTR(space_info, force_chunk_alloc),
954 #endif
955 	NULL,
956 };
957 ATTRIBUTE_GROUPS(space_info);
958 
959 static void space_info_release(struct kobject *kobj)
960 {
961 	struct btrfs_space_info *sinfo = to_space_info(kobj);
962 	kfree(sinfo);
963 }
964 
965 static const struct kobj_type space_info_ktype = {
966 	.sysfs_ops = &kobj_sysfs_ops,
967 	.release = space_info_release,
968 	.default_groups = space_info_groups,
969 };
970 
971 /*
972  * Allocation information about block groups.
973  *
974  * Path: /sys/fs/btrfs/<uuid>/allocation/
975  */
976 static const struct attribute *allocation_attrs[] = {
977 	BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
978 	BTRFS_ATTR_PTR(allocation, global_rsv_size),
979 	NULL,
980 };
981 
982 static ssize_t btrfs_label_show(struct kobject *kobj,
983 				struct kobj_attribute *a, char *buf)
984 {
985 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
986 	char *label = fs_info->super_copy->label;
987 	ssize_t ret;
988 
989 	spin_lock(&fs_info->super_lock);
990 	ret = sysfs_emit(buf, label[0] ? "%s\n" : "%s", label);
991 	spin_unlock(&fs_info->super_lock);
992 
993 	return ret;
994 }
995 
996 static ssize_t btrfs_label_store(struct kobject *kobj,
997 				 struct kobj_attribute *a,
998 				 const char *buf, size_t len)
999 {
1000 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1001 	size_t p_len;
1002 
1003 	if (!fs_info)
1004 		return -EPERM;
1005 
1006 	if (sb_rdonly(fs_info->sb))
1007 		return -EROFS;
1008 
1009 	/*
1010 	 * p_len is the len until the first occurrence of either
1011 	 * '\n' or '\0'
1012 	 */
1013 	p_len = strcspn(buf, "\n");
1014 
1015 	if (p_len >= BTRFS_LABEL_SIZE)
1016 		return -EINVAL;
1017 
1018 	spin_lock(&fs_info->super_lock);
1019 	memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
1020 	memcpy(fs_info->super_copy->label, buf, p_len);
1021 	spin_unlock(&fs_info->super_lock);
1022 
1023 	/*
1024 	 * We don't want to do full transaction commit from inside sysfs
1025 	 */
1026 	set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
1027 	wake_up_process(fs_info->transaction_kthread);
1028 
1029 	return len;
1030 }
1031 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
1032 
1033 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
1034 				struct kobj_attribute *a, char *buf)
1035 {
1036 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1037 
1038 	return sysfs_emit(buf, "%u\n", fs_info->super_copy->nodesize);
1039 }
1040 
1041 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
1042 
1043 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
1044 				struct kobj_attribute *a, char *buf)
1045 {
1046 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1047 
1048 	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
1049 }
1050 
1051 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
1052 
1053 static ssize_t btrfs_commit_stats_show(struct kobject *kobj,
1054 				       struct kobj_attribute *a, char *buf)
1055 {
1056 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1057 
1058 	return sysfs_emit(buf,
1059 		"commits %llu\n"
1060 		"last_commit_ms %llu\n"
1061 		"max_commit_ms %llu\n"
1062 		"total_commit_ms %llu\n",
1063 		fs_info->commit_stats.commit_count,
1064 		div_u64(fs_info->commit_stats.last_commit_dur, NSEC_PER_MSEC),
1065 		div_u64(fs_info->commit_stats.max_commit_dur, NSEC_PER_MSEC),
1066 		div_u64(fs_info->commit_stats.total_commit_dur, NSEC_PER_MSEC));
1067 }
1068 
1069 static ssize_t btrfs_commit_stats_store(struct kobject *kobj,
1070 					struct kobj_attribute *a,
1071 					const char *buf, size_t len)
1072 {
1073 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1074 	unsigned long val;
1075 	int ret;
1076 
1077 	if (!fs_info)
1078 		return -EPERM;
1079 
1080 	if (!capable(CAP_SYS_RESOURCE))
1081 		return -EPERM;
1082 
1083 	ret = kstrtoul(buf, 10, &val);
1084 	if (ret)
1085 		return ret;
1086 	if (val)
1087 		return -EINVAL;
1088 
1089 	WRITE_ONCE(fs_info->commit_stats.max_commit_dur, 0);
1090 
1091 	return len;
1092 }
1093 BTRFS_ATTR_RW(, commit_stats, btrfs_commit_stats_show, btrfs_commit_stats_store);
1094 
1095 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
1096 				struct kobj_attribute *a, char *buf)
1097 {
1098 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1099 
1100 	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
1101 }
1102 
1103 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
1104 
1105 static ssize_t quota_override_show(struct kobject *kobj,
1106 				   struct kobj_attribute *a, char *buf)
1107 {
1108 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1109 	int quota_override;
1110 
1111 	quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1112 	return sysfs_emit(buf, "%d\n", quota_override);
1113 }
1114 
1115 static ssize_t quota_override_store(struct kobject *kobj,
1116 				    struct kobj_attribute *a,
1117 				    const char *buf, size_t len)
1118 {
1119 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1120 	unsigned long knob;
1121 	int err;
1122 
1123 	if (!fs_info)
1124 		return -EPERM;
1125 
1126 	if (!capable(CAP_SYS_RESOURCE))
1127 		return -EPERM;
1128 
1129 	err = kstrtoul(buf, 10, &knob);
1130 	if (err)
1131 		return err;
1132 	if (knob > 1)
1133 		return -EINVAL;
1134 
1135 	if (knob)
1136 		set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1137 	else
1138 		clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1139 
1140 	return len;
1141 }
1142 
1143 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
1144 
1145 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
1146 				struct kobj_attribute *a, char *buf)
1147 {
1148 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1149 
1150 	return sysfs_emit(buf, "%pU\n", fs_info->fs_devices->metadata_uuid);
1151 }
1152 
1153 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
1154 
1155 static ssize_t btrfs_checksum_show(struct kobject *kobj,
1156 				   struct kobj_attribute *a, char *buf)
1157 {
1158 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1159 	u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
1160 
1161 	return sysfs_emit(buf, "%s (%s)\n",
1162 			  btrfs_super_csum_name(csum_type),
1163 			  crypto_shash_driver_name(fs_info->csum_shash));
1164 }
1165 
1166 BTRFS_ATTR(, checksum, btrfs_checksum_show);
1167 
1168 static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
1169 		struct kobj_attribute *a, char *buf)
1170 {
1171 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1172 	const char *str;
1173 
1174 	switch (READ_ONCE(fs_info->exclusive_operation)) {
1175 		case  BTRFS_EXCLOP_NONE:
1176 			str = "none\n";
1177 			break;
1178 		case BTRFS_EXCLOP_BALANCE:
1179 			str = "balance\n";
1180 			break;
1181 		case BTRFS_EXCLOP_BALANCE_PAUSED:
1182 			str = "balance paused\n";
1183 			break;
1184 		case BTRFS_EXCLOP_DEV_ADD:
1185 			str = "device add\n";
1186 			break;
1187 		case BTRFS_EXCLOP_DEV_REMOVE:
1188 			str = "device remove\n";
1189 			break;
1190 		case BTRFS_EXCLOP_DEV_REPLACE:
1191 			str = "device replace\n";
1192 			break;
1193 		case BTRFS_EXCLOP_RESIZE:
1194 			str = "resize\n";
1195 			break;
1196 		case BTRFS_EXCLOP_SWAP_ACTIVATE:
1197 			str = "swap activate\n";
1198 			break;
1199 		default:
1200 			str = "UNKNOWN\n";
1201 			break;
1202 	}
1203 	return sysfs_emit(buf, "%s", str);
1204 }
1205 BTRFS_ATTR(, exclusive_operation, btrfs_exclusive_operation_show);
1206 
1207 static ssize_t btrfs_generation_show(struct kobject *kobj,
1208 				     struct kobj_attribute *a, char *buf)
1209 {
1210 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1211 
1212 	return sysfs_emit(buf, "%llu\n", btrfs_get_fs_generation(fs_info));
1213 }
1214 BTRFS_ATTR(, generation, btrfs_generation_show);
1215 
1216 static ssize_t btrfs_temp_fsid_show(struct kobject *kobj,
1217 				    struct kobj_attribute *a, char *buf)
1218 {
1219 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1220 
1221 	return sysfs_emit(buf, "%d\n", fs_info->fs_devices->temp_fsid);
1222 }
1223 BTRFS_ATTR(, temp_fsid, btrfs_temp_fsid_show);
1224 
1225 static const char * const btrfs_read_policy_name[] = { "pid" };
1226 
1227 static ssize_t btrfs_read_policy_show(struct kobject *kobj,
1228 				      struct kobj_attribute *a, char *buf)
1229 {
1230 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1231 	ssize_t ret = 0;
1232 	int i;
1233 
1234 	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1235 		if (fs_devices->read_policy == i)
1236 			ret += sysfs_emit_at(buf, ret, "%s[%s]",
1237 					 (ret == 0 ? "" : " "),
1238 					 btrfs_read_policy_name[i]);
1239 		else
1240 			ret += sysfs_emit_at(buf, ret, "%s%s",
1241 					 (ret == 0 ? "" : " "),
1242 					 btrfs_read_policy_name[i]);
1243 	}
1244 
1245 	ret += sysfs_emit_at(buf, ret, "\n");
1246 
1247 	return ret;
1248 }
1249 
1250 static ssize_t btrfs_read_policy_store(struct kobject *kobj,
1251 				       struct kobj_attribute *a,
1252 				       const char *buf, size_t len)
1253 {
1254 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1255 	int i;
1256 
1257 	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1258 		if (sysfs_streq(buf, btrfs_read_policy_name[i])) {
1259 			if (i != fs_devices->read_policy) {
1260 				fs_devices->read_policy = i;
1261 				btrfs_info(fs_devices->fs_info,
1262 					   "read policy set to '%s'",
1263 					   btrfs_read_policy_name[i]);
1264 			}
1265 			return len;
1266 		}
1267 	}
1268 
1269 	return -EINVAL;
1270 }
1271 BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store);
1272 
1273 static ssize_t btrfs_bg_reclaim_threshold_show(struct kobject *kobj,
1274 					       struct kobj_attribute *a,
1275 					       char *buf)
1276 {
1277 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1278 
1279 	return sysfs_emit(buf, "%d\n", READ_ONCE(fs_info->bg_reclaim_threshold));
1280 }
1281 
1282 static ssize_t btrfs_bg_reclaim_threshold_store(struct kobject *kobj,
1283 						struct kobj_attribute *a,
1284 						const char *buf, size_t len)
1285 {
1286 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1287 	int thresh;
1288 	int ret;
1289 
1290 	ret = kstrtoint(buf, 10, &thresh);
1291 	if (ret)
1292 		return ret;
1293 
1294 #ifdef CONFIG_BTRFS_DEBUG
1295 	if (thresh != 0 && (thresh > 100))
1296 		return -EINVAL;
1297 #else
1298 	if (thresh != 0 && (thresh <= 50 || thresh > 100))
1299 		return -EINVAL;
1300 #endif
1301 
1302 	WRITE_ONCE(fs_info->bg_reclaim_threshold, thresh);
1303 
1304 	return len;
1305 }
1306 BTRFS_ATTR_RW(, bg_reclaim_threshold, btrfs_bg_reclaim_threshold_show,
1307 	      btrfs_bg_reclaim_threshold_store);
1308 
1309 /*
1310  * Per-filesystem information and stats.
1311  *
1312  * Path: /sys/fs/btrfs/<uuid>/
1313  */
1314 static const struct attribute *btrfs_attrs[] = {
1315 	BTRFS_ATTR_PTR(, label),
1316 	BTRFS_ATTR_PTR(, nodesize),
1317 	BTRFS_ATTR_PTR(, sectorsize),
1318 	BTRFS_ATTR_PTR(, clone_alignment),
1319 	BTRFS_ATTR_PTR(, quota_override),
1320 	BTRFS_ATTR_PTR(, metadata_uuid),
1321 	BTRFS_ATTR_PTR(, checksum),
1322 	BTRFS_ATTR_PTR(, exclusive_operation),
1323 	BTRFS_ATTR_PTR(, generation),
1324 	BTRFS_ATTR_PTR(, read_policy),
1325 	BTRFS_ATTR_PTR(, bg_reclaim_threshold),
1326 	BTRFS_ATTR_PTR(, commit_stats),
1327 	BTRFS_ATTR_PTR(, temp_fsid),
1328 	NULL,
1329 };
1330 
1331 static void btrfs_release_fsid_kobj(struct kobject *kobj)
1332 {
1333 	struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
1334 
1335 	memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
1336 	complete(&fs_devs->kobj_unregister);
1337 }
1338 
1339 static const struct kobj_type btrfs_ktype = {
1340 	.sysfs_ops	= &kobj_sysfs_ops,
1341 	.release	= btrfs_release_fsid_kobj,
1342 };
1343 
1344 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
1345 {
1346 	if (kobj->ktype != &btrfs_ktype)
1347 		return NULL;
1348 	return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
1349 }
1350 
1351 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
1352 {
1353 	if (kobj->ktype != &btrfs_ktype)
1354 		return NULL;
1355 	return to_fs_devs(kobj)->fs_info;
1356 }
1357 
1358 static struct kobject *get_btrfs_kobj(struct kobject *kobj)
1359 {
1360 	while (kobj) {
1361 		if (kobj->ktype == &btrfs_ktype)
1362 			return kobj;
1363 		kobj = kobj->parent;
1364 	}
1365 	return NULL;
1366 }
1367 
1368 #define NUM_FEATURE_BITS 64
1369 #define BTRFS_FEATURE_NAME_MAX 13
1370 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
1371 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
1372 
1373 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names) ==
1374 	      ARRAY_SIZE(btrfs_feature_attrs));
1375 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names[0]) ==
1376 	      ARRAY_SIZE(btrfs_feature_attrs[0]));
1377 
1378 static const u64 supported_feature_masks[FEAT_MAX] = {
1379 	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
1380 	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
1381 	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
1382 };
1383 
1384 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
1385 {
1386 	int set;
1387 
1388 	for (set = 0; set < FEAT_MAX; set++) {
1389 		int i;
1390 		struct attribute *attrs[2];
1391 		struct attribute_group agroup = {
1392 			.name = "features",
1393 			.attrs = attrs,
1394 		};
1395 		u64 features = get_features(fs_info, set);
1396 		features &= ~supported_feature_masks[set];
1397 
1398 		if (!features)
1399 			continue;
1400 
1401 		attrs[1] = NULL;
1402 		for (i = 0; i < NUM_FEATURE_BITS; i++) {
1403 			struct btrfs_feature_attr *fa;
1404 
1405 			if (!(features & (1ULL << i)))
1406 				continue;
1407 
1408 			fa = &btrfs_feature_attrs[set][i];
1409 			attrs[0] = &fa->kobj_attr.attr;
1410 			if (add) {
1411 				int ret;
1412 				ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
1413 							&agroup);
1414 				if (ret)
1415 					return ret;
1416 			} else
1417 				sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
1418 						    &agroup);
1419 		}
1420 
1421 	}
1422 	return 0;
1423 }
1424 
1425 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1426 {
1427 	if (fs_devs->devinfo_kobj) {
1428 		kobject_del(fs_devs->devinfo_kobj);
1429 		kobject_put(fs_devs->devinfo_kobj);
1430 		fs_devs->devinfo_kobj = NULL;
1431 	}
1432 
1433 	if (fs_devs->devices_kobj) {
1434 		kobject_del(fs_devs->devices_kobj);
1435 		kobject_put(fs_devs->devices_kobj);
1436 		fs_devs->devices_kobj = NULL;
1437 	}
1438 
1439 	if (fs_devs->fsid_kobj.state_initialized) {
1440 		kobject_del(&fs_devs->fsid_kobj);
1441 		kobject_put(&fs_devs->fsid_kobj);
1442 		wait_for_completion(&fs_devs->kobj_unregister);
1443 	}
1444 }
1445 
1446 /* when fs_devs is NULL it will remove all fsid kobject */
1447 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1448 {
1449 	struct list_head *fs_uuids = btrfs_get_fs_uuids();
1450 
1451 	if (fs_devs) {
1452 		__btrfs_sysfs_remove_fsid(fs_devs);
1453 		return;
1454 	}
1455 
1456 	list_for_each_entry(fs_devs, fs_uuids, fs_list) {
1457 		__btrfs_sysfs_remove_fsid(fs_devs);
1458 	}
1459 }
1460 
1461 static void btrfs_sysfs_remove_fs_devices(struct btrfs_fs_devices *fs_devices)
1462 {
1463 	struct btrfs_device *device;
1464 	struct btrfs_fs_devices *seed;
1465 
1466 	list_for_each_entry(device, &fs_devices->devices, dev_list)
1467 		btrfs_sysfs_remove_device(device);
1468 
1469 	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1470 		list_for_each_entry(device, &seed->devices, dev_list)
1471 			btrfs_sysfs_remove_device(device);
1472 	}
1473 }
1474 
1475 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
1476 {
1477 	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1478 
1479 	sysfs_remove_link(fsid_kobj, "bdi");
1480 
1481 	if (fs_info->space_info_kobj) {
1482 		sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
1483 		kobject_del(fs_info->space_info_kobj);
1484 		kobject_put(fs_info->space_info_kobj);
1485 	}
1486 	if (fs_info->discard_kobj) {
1487 		sysfs_remove_files(fs_info->discard_kobj, discard_attrs);
1488 		kobject_del(fs_info->discard_kobj);
1489 		kobject_put(fs_info->discard_kobj);
1490 	}
1491 #ifdef CONFIG_BTRFS_DEBUG
1492 	if (fs_info->debug_kobj) {
1493 		sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1494 		kobject_del(fs_info->debug_kobj);
1495 		kobject_put(fs_info->debug_kobj);
1496 	}
1497 #endif
1498 	addrm_unknown_feature_attrs(fs_info, false);
1499 	sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1500 	sysfs_remove_files(fsid_kobj, btrfs_attrs);
1501 	btrfs_sysfs_remove_fs_devices(fs_info->fs_devices);
1502 }
1503 
1504 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
1505 	[FEAT_COMPAT]	 = "compat",
1506 	[FEAT_COMPAT_RO] = "compat_ro",
1507 	[FEAT_INCOMPAT]	 = "incompat",
1508 };
1509 
1510 const char *btrfs_feature_set_name(enum btrfs_feature_set set)
1511 {
1512 	return btrfs_feature_set_names[set];
1513 }
1514 
1515 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
1516 {
1517 	size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
1518 	int len = 0;
1519 	int i;
1520 	char *str;
1521 
1522 	str = kmalloc(bufsize, GFP_KERNEL);
1523 	if (!str)
1524 		return str;
1525 
1526 	for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1527 		const char *name;
1528 
1529 		if (!(flags & (1ULL << i)))
1530 			continue;
1531 
1532 		name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
1533 		len += scnprintf(str + len, bufsize - len, "%s%s",
1534 				len ? "," : "", name);
1535 	}
1536 
1537 	return str;
1538 }
1539 
1540 static void init_feature_attrs(void)
1541 {
1542 	struct btrfs_feature_attr *fa;
1543 	int set, i;
1544 
1545 	memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
1546 	memset(btrfs_unknown_feature_names, 0,
1547 	       sizeof(btrfs_unknown_feature_names));
1548 
1549 	for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
1550 		struct btrfs_feature_attr *sfa;
1551 		struct attribute *a = btrfs_supported_feature_attrs[i];
1552 		int bit;
1553 		sfa = attr_to_btrfs_feature_attr(a);
1554 		bit = ilog2(sfa->feature_bit);
1555 		fa = &btrfs_feature_attrs[sfa->feature_set][bit];
1556 
1557 		fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
1558 	}
1559 
1560 	for (set = 0; set < FEAT_MAX; set++) {
1561 		for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1562 			char *name = btrfs_unknown_feature_names[set][i];
1563 			fa = &btrfs_feature_attrs[set][i];
1564 
1565 			if (fa->kobj_attr.attr.name)
1566 				continue;
1567 
1568 			snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
1569 				 btrfs_feature_set_names[set], i);
1570 
1571 			fa->kobj_attr.attr.name = name;
1572 			fa->kobj_attr.attr.mode = S_IRUGO;
1573 			fa->feature_set = set;
1574 			fa->feature_bit = 1ULL << i;
1575 		}
1576 	}
1577 }
1578 
1579 /*
1580  * Create a sysfs entry for a given block group type at path
1581  * /sys/fs/btrfs/UUID/allocation/data/TYPE
1582  */
1583 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
1584 {
1585 	struct btrfs_fs_info *fs_info = cache->fs_info;
1586 	struct btrfs_space_info *space_info = cache->space_info;
1587 	struct raid_kobject *rkobj;
1588 	const int index = btrfs_bg_flags_to_raid_index(cache->flags);
1589 	unsigned int nofs_flag;
1590 	int ret;
1591 
1592 	/*
1593 	 * Setup a NOFS context because kobject_add(), deep in its call chain,
1594 	 * does GFP_KERNEL allocations, and we are often called in a context
1595 	 * where if reclaim is triggered we can deadlock (we are either holding
1596 	 * a transaction handle or some lock required for a transaction
1597 	 * commit).
1598 	 */
1599 	nofs_flag = memalloc_nofs_save();
1600 
1601 	rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
1602 	if (!rkobj) {
1603 		memalloc_nofs_restore(nofs_flag);
1604 		btrfs_warn(cache->fs_info,
1605 				"couldn't alloc memory for raid level kobject");
1606 		return;
1607 	}
1608 
1609 	rkobj->flags = cache->flags;
1610 	kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
1611 
1612 	/*
1613 	 * We call this either on mount, or if we've created a block group for a
1614 	 * new index type while running (i.e. when restriping).  The running
1615 	 * case is tricky because we could race with other threads, so we need
1616 	 * to have this check to make sure we didn't already init the kobject.
1617 	 *
1618 	 * We don't have to protect on the free side because it only happens on
1619 	 * unmount.
1620 	 */
1621 	spin_lock(&space_info->lock);
1622 	if (space_info->block_group_kobjs[index]) {
1623 		spin_unlock(&space_info->lock);
1624 		kobject_put(&rkobj->kobj);
1625 		return;
1626 	} else {
1627 		space_info->block_group_kobjs[index] = &rkobj->kobj;
1628 	}
1629 	spin_unlock(&space_info->lock);
1630 
1631 	ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
1632 			  btrfs_bg_type_to_raid_name(rkobj->flags));
1633 	memalloc_nofs_restore(nofs_flag);
1634 	if (ret) {
1635 		spin_lock(&space_info->lock);
1636 		space_info->block_group_kobjs[index] = NULL;
1637 		spin_unlock(&space_info->lock);
1638 		kobject_put(&rkobj->kobj);
1639 		btrfs_warn(fs_info,
1640 			"failed to add kobject for block cache, ignoring");
1641 		return;
1642 	}
1643 }
1644 
1645 /*
1646  * Remove sysfs directories for all block group types of a given space info and
1647  * the space info as well
1648  */
1649 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
1650 {
1651 	int i;
1652 
1653 	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1654 		struct kobject *kobj;
1655 
1656 		kobj = space_info->block_group_kobjs[i];
1657 		space_info->block_group_kobjs[i] = NULL;
1658 		if (kobj) {
1659 			kobject_del(kobj);
1660 			kobject_put(kobj);
1661 		}
1662 	}
1663 	kobject_del(&space_info->kobj);
1664 	kobject_put(&space_info->kobj);
1665 }
1666 
1667 static const char *alloc_name(u64 flags)
1668 {
1669 	switch (flags) {
1670 	case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
1671 		return "mixed";
1672 	case BTRFS_BLOCK_GROUP_METADATA:
1673 		return "metadata";
1674 	case BTRFS_BLOCK_GROUP_DATA:
1675 		return "data";
1676 	case BTRFS_BLOCK_GROUP_SYSTEM:
1677 		return "system";
1678 	default:
1679 		WARN_ON(1);
1680 		return "invalid-combination";
1681 	}
1682 }
1683 
1684 /*
1685  * Create a sysfs entry for a space info type at path
1686  * /sys/fs/btrfs/UUID/allocation/TYPE
1687  */
1688 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
1689 				    struct btrfs_space_info *space_info)
1690 {
1691 	int ret;
1692 
1693 	ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
1694 				   fs_info->space_info_kobj, "%s",
1695 				   alloc_name(space_info->flags));
1696 	if (ret) {
1697 		kobject_put(&space_info->kobj);
1698 		return ret;
1699 	}
1700 
1701 	return 0;
1702 }
1703 
1704 void btrfs_sysfs_remove_device(struct btrfs_device *device)
1705 {
1706 	struct kobject *devices_kobj;
1707 
1708 	/*
1709 	 * Seed fs_devices devices_kobj aren't used, fetch kobject from the
1710 	 * fs_info::fs_devices.
1711 	 */
1712 	devices_kobj = device->fs_info->fs_devices->devices_kobj;
1713 	ASSERT(devices_kobj);
1714 
1715 	if (device->bdev)
1716 		sysfs_remove_link(devices_kobj, bdev_kobj(device->bdev)->name);
1717 
1718 	if (device->devid_kobj.state_initialized) {
1719 		kobject_del(&device->devid_kobj);
1720 		kobject_put(&device->devid_kobj);
1721 		wait_for_completion(&device->kobj_unregister);
1722 	}
1723 }
1724 
1725 static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj,
1726 					         struct kobj_attribute *a,
1727 					         char *buf)
1728 {
1729 	int val;
1730 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1731 						   devid_kobj);
1732 
1733 	val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
1734 
1735 	return sysfs_emit(buf, "%d\n", val);
1736 }
1737 BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show);
1738 
1739 static ssize_t btrfs_devinfo_missing_show(struct kobject *kobj,
1740 					struct kobj_attribute *a, char *buf)
1741 {
1742 	int val;
1743 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1744 						   devid_kobj);
1745 
1746 	val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
1747 
1748 	return sysfs_emit(buf, "%d\n", val);
1749 }
1750 BTRFS_ATTR(devid, missing, btrfs_devinfo_missing_show);
1751 
1752 static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj,
1753 					         struct kobj_attribute *a,
1754 					         char *buf)
1755 {
1756 	int val;
1757 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1758 						   devid_kobj);
1759 
1760 	val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
1761 
1762 	return sysfs_emit(buf, "%d\n", val);
1763 }
1764 BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show);
1765 
1766 static ssize_t btrfs_devinfo_scrub_speed_max_show(struct kobject *kobj,
1767 					     struct kobj_attribute *a,
1768 					     char *buf)
1769 {
1770 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1771 						   devid_kobj);
1772 
1773 	return sysfs_emit(buf, "%llu\n", READ_ONCE(device->scrub_speed_max));
1774 }
1775 
1776 static ssize_t btrfs_devinfo_scrub_speed_max_store(struct kobject *kobj,
1777 					      struct kobj_attribute *a,
1778 					      const char *buf, size_t len)
1779 {
1780 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1781 						   devid_kobj);
1782 	char *endptr;
1783 	unsigned long long limit;
1784 
1785 	limit = memparse(buf, &endptr);
1786 	WRITE_ONCE(device->scrub_speed_max, limit);
1787 	return len;
1788 }
1789 BTRFS_ATTR_RW(devid, scrub_speed_max, btrfs_devinfo_scrub_speed_max_show,
1790 	      btrfs_devinfo_scrub_speed_max_store);
1791 
1792 static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj,
1793 					    struct kobj_attribute *a, char *buf)
1794 {
1795 	int val;
1796 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1797 						   devid_kobj);
1798 
1799 	val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
1800 
1801 	return sysfs_emit(buf, "%d\n", val);
1802 }
1803 BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show);
1804 
1805 static ssize_t btrfs_devinfo_fsid_show(struct kobject *kobj,
1806 				       struct kobj_attribute *a, char *buf)
1807 {
1808 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1809 						   devid_kobj);
1810 
1811 	return sysfs_emit(buf, "%pU\n", device->fs_devices->fsid);
1812 }
1813 BTRFS_ATTR(devid, fsid, btrfs_devinfo_fsid_show);
1814 
1815 static ssize_t btrfs_devinfo_error_stats_show(struct kobject *kobj,
1816 		struct kobj_attribute *a, char *buf)
1817 {
1818 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1819 						   devid_kobj);
1820 
1821 	if (!device->dev_stats_valid)
1822 		return sysfs_emit(buf, "invalid\n");
1823 
1824 	/*
1825 	 * Print all at once so we get a snapshot of all values from the same
1826 	 * time. Keep them in sync and in order of definition of
1827 	 * btrfs_dev_stat_values.
1828 	 */
1829 	return sysfs_emit(buf,
1830 		"write_errs %d\n"
1831 		"read_errs %d\n"
1832 		"flush_errs %d\n"
1833 		"corruption_errs %d\n"
1834 		"generation_errs %d\n",
1835 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_WRITE_ERRS),
1836 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_READ_ERRS),
1837 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_FLUSH_ERRS),
1838 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_CORRUPTION_ERRS),
1839 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_GENERATION_ERRS));
1840 }
1841 BTRFS_ATTR(devid, error_stats, btrfs_devinfo_error_stats_show);
1842 
1843 /*
1844  * Information about one device.
1845  *
1846  * Path: /sys/fs/btrfs/<uuid>/devinfo/<devid>/
1847  */
1848 static struct attribute *devid_attrs[] = {
1849 	BTRFS_ATTR_PTR(devid, error_stats),
1850 	BTRFS_ATTR_PTR(devid, fsid),
1851 	BTRFS_ATTR_PTR(devid, in_fs_metadata),
1852 	BTRFS_ATTR_PTR(devid, missing),
1853 	BTRFS_ATTR_PTR(devid, replace_target),
1854 	BTRFS_ATTR_PTR(devid, scrub_speed_max),
1855 	BTRFS_ATTR_PTR(devid, writeable),
1856 	NULL
1857 };
1858 ATTRIBUTE_GROUPS(devid);
1859 
1860 static void btrfs_release_devid_kobj(struct kobject *kobj)
1861 {
1862 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1863 						   devid_kobj);
1864 
1865 	memset(&device->devid_kobj, 0, sizeof(struct kobject));
1866 	complete(&device->kobj_unregister);
1867 }
1868 
1869 static const struct kobj_type devid_ktype = {
1870 	.sysfs_ops	= &kobj_sysfs_ops,
1871 	.default_groups = devid_groups,
1872 	.release	= btrfs_release_devid_kobj,
1873 };
1874 
1875 int btrfs_sysfs_add_device(struct btrfs_device *device)
1876 {
1877 	int ret;
1878 	unsigned int nofs_flag;
1879 	struct kobject *devices_kobj;
1880 	struct kobject *devinfo_kobj;
1881 
1882 	/*
1883 	 * Make sure we use the fs_info::fs_devices to fetch the kobjects even
1884 	 * for the seed fs_devices
1885 	 */
1886 	devices_kobj = device->fs_info->fs_devices->devices_kobj;
1887 	devinfo_kobj = device->fs_info->fs_devices->devinfo_kobj;
1888 	ASSERT(devices_kobj);
1889 	ASSERT(devinfo_kobj);
1890 
1891 	nofs_flag = memalloc_nofs_save();
1892 
1893 	if (device->bdev) {
1894 		struct kobject *disk_kobj = bdev_kobj(device->bdev);
1895 
1896 		ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
1897 		if (ret) {
1898 			btrfs_warn(device->fs_info,
1899 				"creating sysfs device link for devid %llu failed: %d",
1900 				device->devid, ret);
1901 			goto out;
1902 		}
1903 	}
1904 
1905 	init_completion(&device->kobj_unregister);
1906 	ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype,
1907 				   devinfo_kobj, "%llu", device->devid);
1908 	if (ret) {
1909 		kobject_put(&device->devid_kobj);
1910 		btrfs_warn(device->fs_info,
1911 			   "devinfo init for devid %llu failed: %d",
1912 			   device->devid, ret);
1913 	}
1914 
1915 out:
1916 	memalloc_nofs_restore(nofs_flag);
1917 	return ret;
1918 }
1919 
1920 static int btrfs_sysfs_add_fs_devices(struct btrfs_fs_devices *fs_devices)
1921 {
1922 	int ret;
1923 	struct btrfs_device *device;
1924 	struct btrfs_fs_devices *seed;
1925 
1926 	list_for_each_entry(device, &fs_devices->devices, dev_list) {
1927 		ret = btrfs_sysfs_add_device(device);
1928 		if (ret)
1929 			goto fail;
1930 	}
1931 
1932 	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1933 		list_for_each_entry(device, &seed->devices, dev_list) {
1934 			ret = btrfs_sysfs_add_device(device);
1935 			if (ret)
1936 				goto fail;
1937 		}
1938 	}
1939 
1940 	return 0;
1941 
1942 fail:
1943 	btrfs_sysfs_remove_fs_devices(fs_devices);
1944 	return ret;
1945 }
1946 
1947 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1948 {
1949 	int ret;
1950 
1951 	ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
1952 	if (ret)
1953 		pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
1954 			action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
1955 			&disk_to_dev(bdev->bd_disk)->kobj);
1956 }
1957 
1958 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices)
1959 
1960 {
1961 	char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
1962 
1963 	/*
1964 	 * Sprouting changes fsid of the mounted filesystem, rename the fsid
1965 	 * directory
1966 	 */
1967 	snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fs_devices->fsid);
1968 	if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
1969 		btrfs_warn(fs_devices->fs_info,
1970 				"sysfs: failed to create fsid for sprout");
1971 }
1972 
1973 void btrfs_sysfs_update_devid(struct btrfs_device *device)
1974 {
1975 	char tmp[24];
1976 
1977 	snprintf(tmp, sizeof(tmp), "%llu", device->devid);
1978 
1979 	if (kobject_rename(&device->devid_kobj, tmp))
1980 		btrfs_warn(device->fs_devices->fs_info,
1981 			   "sysfs: failed to update devid for %llu",
1982 			   device->devid);
1983 }
1984 
1985 /* /sys/fs/btrfs/ entry */
1986 static struct kset *btrfs_kset;
1987 
1988 /*
1989  * Creates:
1990  *		/sys/fs/btrfs/UUID
1991  *
1992  * Can be called by the device discovery thread.
1993  */
1994 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
1995 {
1996 	int error;
1997 
1998 	init_completion(&fs_devs->kobj_unregister);
1999 	fs_devs->fsid_kobj.kset = btrfs_kset;
2000 	error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
2001 				     "%pU", fs_devs->fsid);
2002 	if (error) {
2003 		kobject_put(&fs_devs->fsid_kobj);
2004 		return error;
2005 	}
2006 
2007 	fs_devs->devices_kobj = kobject_create_and_add("devices",
2008 						       &fs_devs->fsid_kobj);
2009 	if (!fs_devs->devices_kobj) {
2010 		btrfs_err(fs_devs->fs_info,
2011 			  "failed to init sysfs device interface");
2012 		btrfs_sysfs_remove_fsid(fs_devs);
2013 		return -ENOMEM;
2014 	}
2015 
2016 	fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
2017 						       &fs_devs->fsid_kobj);
2018 	if (!fs_devs->devinfo_kobj) {
2019 		btrfs_err(fs_devs->fs_info,
2020 			  "failed to init sysfs devinfo kobject");
2021 		btrfs_sysfs_remove_fsid(fs_devs);
2022 		return -ENOMEM;
2023 	}
2024 
2025 	return 0;
2026 }
2027 
2028 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
2029 {
2030 	int error;
2031 	struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
2032 	struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
2033 
2034 	error = btrfs_sysfs_add_fs_devices(fs_devs);
2035 	if (error)
2036 		return error;
2037 
2038 	error = sysfs_create_files(fsid_kobj, btrfs_attrs);
2039 	if (error) {
2040 		btrfs_sysfs_remove_fs_devices(fs_devs);
2041 		return error;
2042 	}
2043 
2044 	error = sysfs_create_group(fsid_kobj,
2045 				   &btrfs_feature_attr_group);
2046 	if (error)
2047 		goto failure;
2048 
2049 #ifdef CONFIG_BTRFS_DEBUG
2050 	fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
2051 	if (!fs_info->debug_kobj) {
2052 		error = -ENOMEM;
2053 		goto failure;
2054 	}
2055 
2056 	error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
2057 	if (error)
2058 		goto failure;
2059 #endif
2060 
2061 	/* Discard directory */
2062 	fs_info->discard_kobj = kobject_create_and_add("discard", fsid_kobj);
2063 	if (!fs_info->discard_kobj) {
2064 		error = -ENOMEM;
2065 		goto failure;
2066 	}
2067 
2068 	error = sysfs_create_files(fs_info->discard_kobj, discard_attrs);
2069 	if (error)
2070 		goto failure;
2071 
2072 	error = addrm_unknown_feature_attrs(fs_info, true);
2073 	if (error)
2074 		goto failure;
2075 
2076 	error = sysfs_create_link(fsid_kobj, &fs_info->sb->s_bdi->dev->kobj, "bdi");
2077 	if (error)
2078 		goto failure;
2079 
2080 	fs_info->space_info_kobj = kobject_create_and_add("allocation",
2081 						  fsid_kobj);
2082 	if (!fs_info->space_info_kobj) {
2083 		error = -ENOMEM;
2084 		goto failure;
2085 	}
2086 
2087 	error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
2088 	if (error)
2089 		goto failure;
2090 
2091 	return 0;
2092 failure:
2093 	btrfs_sysfs_remove_mounted(fs_info);
2094 	return error;
2095 }
2096 
2097 static ssize_t qgroup_enabled_show(struct kobject *qgroups_kobj,
2098 				   struct kobj_attribute *a,
2099 				   char *buf)
2100 {
2101 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2102 	bool enabled;
2103 
2104 	spin_lock(&fs_info->qgroup_lock);
2105 	enabled = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON;
2106 	spin_unlock(&fs_info->qgroup_lock);
2107 
2108 	return sysfs_emit(buf, "%d\n", enabled);
2109 }
2110 BTRFS_ATTR(qgroups, enabled, qgroup_enabled_show);
2111 
2112 static ssize_t qgroup_mode_show(struct kobject *qgroups_kobj,
2113 				struct kobj_attribute *a,
2114 				char *buf)
2115 {
2116 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2117 	ssize_t ret = 0;
2118 
2119 	spin_lock(&fs_info->qgroup_lock);
2120 	ASSERT(btrfs_qgroup_enabled(fs_info));
2121 	switch (btrfs_qgroup_mode(fs_info)) {
2122 	case BTRFS_QGROUP_MODE_FULL:
2123 		ret = sysfs_emit(buf, "qgroup\n");
2124 		break;
2125 	case BTRFS_QGROUP_MODE_SIMPLE:
2126 		ret = sysfs_emit(buf, "squota\n");
2127 		break;
2128 	default:
2129 		btrfs_warn(fs_info, "unexpected qgroup mode %d\n",
2130 			   btrfs_qgroup_mode(fs_info));
2131 		break;
2132 	}
2133 	spin_unlock(&fs_info->qgroup_lock);
2134 
2135 	return ret;
2136 }
2137 BTRFS_ATTR(qgroups, mode, qgroup_mode_show);
2138 
2139 static ssize_t qgroup_inconsistent_show(struct kobject *qgroups_kobj,
2140 					struct kobj_attribute *a,
2141 					char *buf)
2142 {
2143 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2144 	bool inconsistent;
2145 
2146 	spin_lock(&fs_info->qgroup_lock);
2147 	inconsistent = (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT);
2148 	spin_unlock(&fs_info->qgroup_lock);
2149 
2150 	return sysfs_emit(buf, "%d\n", inconsistent);
2151 }
2152 BTRFS_ATTR(qgroups, inconsistent, qgroup_inconsistent_show);
2153 
2154 static ssize_t qgroup_drop_subtree_thres_show(struct kobject *qgroups_kobj,
2155 					      struct kobj_attribute *a,
2156 					      char *buf)
2157 {
2158 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2159 	u8 result;
2160 
2161 	spin_lock(&fs_info->qgroup_lock);
2162 	result = fs_info->qgroup_drop_subtree_thres;
2163 	spin_unlock(&fs_info->qgroup_lock);
2164 
2165 	return sysfs_emit(buf, "%d\n", result);
2166 }
2167 
2168 static ssize_t qgroup_drop_subtree_thres_store(struct kobject *qgroups_kobj,
2169 					       struct kobj_attribute *a,
2170 					       const char *buf, size_t len)
2171 {
2172 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2173 	u8 new_thres;
2174 	int ret;
2175 
2176 	ret = kstrtou8(buf, 10, &new_thres);
2177 	if (ret)
2178 		return -EINVAL;
2179 
2180 	if (new_thres > BTRFS_MAX_LEVEL)
2181 		return -EINVAL;
2182 
2183 	spin_lock(&fs_info->qgroup_lock);
2184 	fs_info->qgroup_drop_subtree_thres = new_thres;
2185 	spin_unlock(&fs_info->qgroup_lock);
2186 
2187 	return len;
2188 }
2189 BTRFS_ATTR_RW(qgroups, drop_subtree_threshold, qgroup_drop_subtree_thres_show,
2190 	      qgroup_drop_subtree_thres_store);
2191 
2192 /*
2193  * Qgroups global info
2194  *
2195  * Path: /sys/fs/btrfs/<uuid>/qgroups/
2196  */
2197 static struct attribute *qgroups_attrs[] = {
2198 	BTRFS_ATTR_PTR(qgroups, enabled),
2199 	BTRFS_ATTR_PTR(qgroups, inconsistent),
2200 	BTRFS_ATTR_PTR(qgroups, drop_subtree_threshold),
2201 	BTRFS_ATTR_PTR(qgroups, mode),
2202 	NULL
2203 };
2204 ATTRIBUTE_GROUPS(qgroups);
2205 
2206 static void qgroups_release(struct kobject *kobj)
2207 {
2208 	kfree(kobj);
2209 }
2210 
2211 static const struct kobj_type qgroups_ktype = {
2212 	.sysfs_ops = &kobj_sysfs_ops,
2213 	.default_groups = qgroups_groups,
2214 	.release = qgroups_release,
2215 };
2216 
2217 static inline struct btrfs_fs_info *qgroup_kobj_to_fs_info(struct kobject *kobj)
2218 {
2219 	return to_fs_info(kobj->parent->parent);
2220 }
2221 
2222 #define QGROUP_ATTR(_member, _show_name)					\
2223 static ssize_t btrfs_qgroup_show_##_member(struct kobject *qgroup_kobj,		\
2224 					   struct kobj_attribute *a,		\
2225 					   char *buf)				\
2226 {										\
2227 	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2228 	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2229 			struct btrfs_qgroup, kobj);				\
2230 	return btrfs_show_u64(&qgroup->_member, &fs_info->qgroup_lock, buf);	\
2231 }										\
2232 BTRFS_ATTR(qgroup, _show_name, btrfs_qgroup_show_##_member)
2233 
2234 #define QGROUP_RSV_ATTR(_name, _type)						\
2235 static ssize_t btrfs_qgroup_rsv_show_##_name(struct kobject *qgroup_kobj,	\
2236 					     struct kobj_attribute *a,		\
2237 					     char *buf)				\
2238 {										\
2239 	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2240 	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2241 			struct btrfs_qgroup, kobj);				\
2242 	return btrfs_show_u64(&qgroup->rsv.values[_type],			\
2243 			&fs_info->qgroup_lock, buf);				\
2244 }										\
2245 BTRFS_ATTR(qgroup, rsv_##_name, btrfs_qgroup_rsv_show_##_name)
2246 
2247 QGROUP_ATTR(rfer, referenced);
2248 QGROUP_ATTR(excl, exclusive);
2249 QGROUP_ATTR(max_rfer, max_referenced);
2250 QGROUP_ATTR(max_excl, max_exclusive);
2251 QGROUP_ATTR(lim_flags, limit_flags);
2252 QGROUP_RSV_ATTR(data, BTRFS_QGROUP_RSV_DATA);
2253 QGROUP_RSV_ATTR(meta_pertrans, BTRFS_QGROUP_RSV_META_PERTRANS);
2254 QGROUP_RSV_ATTR(meta_prealloc, BTRFS_QGROUP_RSV_META_PREALLOC);
2255 
2256 /*
2257  * Qgroup information.
2258  *
2259  * Path: /sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>/
2260  */
2261 static struct attribute *qgroup_attrs[] = {
2262 	BTRFS_ATTR_PTR(qgroup, referenced),
2263 	BTRFS_ATTR_PTR(qgroup, exclusive),
2264 	BTRFS_ATTR_PTR(qgroup, max_referenced),
2265 	BTRFS_ATTR_PTR(qgroup, max_exclusive),
2266 	BTRFS_ATTR_PTR(qgroup, limit_flags),
2267 	BTRFS_ATTR_PTR(qgroup, rsv_data),
2268 	BTRFS_ATTR_PTR(qgroup, rsv_meta_pertrans),
2269 	BTRFS_ATTR_PTR(qgroup, rsv_meta_prealloc),
2270 	NULL
2271 };
2272 ATTRIBUTE_GROUPS(qgroup);
2273 
2274 static void qgroup_release(struct kobject *kobj)
2275 {
2276 	struct btrfs_qgroup *qgroup = container_of(kobj, struct btrfs_qgroup, kobj);
2277 
2278 	memset(&qgroup->kobj, 0, sizeof(*kobj));
2279 }
2280 
2281 static const struct kobj_type qgroup_ktype = {
2282 	.sysfs_ops = &kobj_sysfs_ops,
2283 	.release = qgroup_release,
2284 	.default_groups = qgroup_groups,
2285 };
2286 
2287 int btrfs_sysfs_add_one_qgroup(struct btrfs_fs_info *fs_info,
2288 				struct btrfs_qgroup *qgroup)
2289 {
2290 	struct kobject *qgroups_kobj = fs_info->qgroups_kobj;
2291 	int ret;
2292 
2293 	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2294 		return 0;
2295 	if (qgroup->kobj.state_initialized)
2296 		return 0;
2297 	if (!qgroups_kobj)
2298 		return -EINVAL;
2299 
2300 	ret = kobject_init_and_add(&qgroup->kobj, &qgroup_ktype, qgroups_kobj,
2301 			"%hu_%llu", btrfs_qgroup_level(qgroup->qgroupid),
2302 			btrfs_qgroup_subvolid(qgroup->qgroupid));
2303 	if (ret < 0)
2304 		kobject_put(&qgroup->kobj);
2305 
2306 	return ret;
2307 }
2308 
2309 void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info)
2310 {
2311 	struct btrfs_qgroup *qgroup;
2312 	struct btrfs_qgroup *next;
2313 
2314 	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2315 		return;
2316 
2317 	rbtree_postorder_for_each_entry_safe(qgroup, next,
2318 					     &fs_info->qgroup_tree, node)
2319 		btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
2320 	if (fs_info->qgroups_kobj) {
2321 		kobject_del(fs_info->qgroups_kobj);
2322 		kobject_put(fs_info->qgroups_kobj);
2323 		fs_info->qgroups_kobj = NULL;
2324 	}
2325 }
2326 
2327 /* Called when qgroups get initialized, thus there is no need for locking */
2328 int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info)
2329 {
2330 	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2331 	struct btrfs_qgroup *qgroup;
2332 	struct btrfs_qgroup *next;
2333 	int ret = 0;
2334 
2335 	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2336 		return 0;
2337 
2338 	ASSERT(fsid_kobj);
2339 	if (fs_info->qgroups_kobj)
2340 		return 0;
2341 
2342 	fs_info->qgroups_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
2343 	if (!fs_info->qgroups_kobj)
2344 		return -ENOMEM;
2345 
2346 	ret = kobject_init_and_add(fs_info->qgroups_kobj, &qgroups_ktype,
2347 				   fsid_kobj, "qgroups");
2348 	if (ret < 0)
2349 		goto out;
2350 
2351 	rbtree_postorder_for_each_entry_safe(qgroup, next,
2352 					     &fs_info->qgroup_tree, node) {
2353 		ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
2354 		if (ret < 0)
2355 			goto out;
2356 	}
2357 
2358 out:
2359 	if (ret < 0)
2360 		btrfs_sysfs_del_qgroups(fs_info);
2361 	return ret;
2362 }
2363 
2364 void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
2365 				struct btrfs_qgroup *qgroup)
2366 {
2367 	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2368 		return;
2369 
2370 	if (qgroup->kobj.state_initialized) {
2371 		kobject_del(&qgroup->kobj);
2372 		kobject_put(&qgroup->kobj);
2373 	}
2374 }
2375 
2376 /*
2377  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
2378  * values in superblock. Call after any changes to incompat/compat_ro flags
2379  */
2380 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info)
2381 {
2382 	struct kobject *fsid_kobj;
2383 	int ret;
2384 
2385 	if (!fs_info)
2386 		return;
2387 
2388 	fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2389 	if (!fsid_kobj->state_initialized)
2390 		return;
2391 
2392 	ret = sysfs_update_group(fsid_kobj, &btrfs_feature_attr_group);
2393 	if (ret < 0)
2394 		btrfs_warn(fs_info,
2395 			   "failed to update /sys/fs/btrfs/%pU/features: %d",
2396 			   fs_info->fs_devices->fsid, ret);
2397 }
2398 
2399 int __init btrfs_init_sysfs(void)
2400 {
2401 	int ret;
2402 
2403 	btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
2404 	if (!btrfs_kset)
2405 		return -ENOMEM;
2406 
2407 	init_feature_attrs();
2408 	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2409 	if (ret)
2410 		goto out2;
2411 	ret = sysfs_merge_group(&btrfs_kset->kobj,
2412 				&btrfs_static_feature_attr_group);
2413 	if (ret)
2414 		goto out_remove_group;
2415 
2416 #ifdef CONFIG_BTRFS_DEBUG
2417 	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2418 	if (ret) {
2419 		sysfs_unmerge_group(&btrfs_kset->kobj,
2420 				    &btrfs_static_feature_attr_group);
2421 		goto out_remove_group;
2422 	}
2423 #endif
2424 
2425 	return 0;
2426 
2427 out_remove_group:
2428 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2429 out2:
2430 	kset_unregister(btrfs_kset);
2431 
2432 	return ret;
2433 }
2434 
2435 void __cold btrfs_exit_sysfs(void)
2436 {
2437 	sysfs_unmerge_group(&btrfs_kset->kobj,
2438 			    &btrfs_static_feature_attr_group);
2439 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2440 #ifdef CONFIG_BTRFS_DEBUG
2441 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2442 #endif
2443 	kset_unregister(btrfs_kset);
2444 }
2445