xref: /linux/fs/btrfs/sysfs.c (revision 955abe0a1b41de5ba61fe4cd614ebc123084d499)
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 	"ignoremetacsums",
389 	"ignoresuperflags",
390 	"all",
391 };
392 
393 static ssize_t supported_rescue_options_show(struct kobject *kobj,
394 					     struct kobj_attribute *a,
395 					     char *buf)
396 {
397 	ssize_t ret = 0;
398 	int i;
399 
400 	for (i = 0; i < ARRAY_SIZE(rescue_opts); i++)
401 		ret += sysfs_emit_at(buf, ret, "%s%s", (i ? " " : ""), rescue_opts[i]);
402 	ret += sysfs_emit_at(buf, ret, "\n");
403 	return ret;
404 }
405 BTRFS_ATTR(static_feature, supported_rescue_options,
406 	   supported_rescue_options_show);
407 
408 static ssize_t supported_sectorsizes_show(struct kobject *kobj,
409 					  struct kobj_attribute *a,
410 					  char *buf)
411 {
412 	ssize_t ret = 0;
413 
414 	/* An artificial limit to only support 4K and PAGE_SIZE */
415 	if (PAGE_SIZE > SZ_4K)
416 		ret += sysfs_emit_at(buf, ret, "%u ", SZ_4K);
417 	ret += sysfs_emit_at(buf, ret, "%lu\n", PAGE_SIZE);
418 
419 	return ret;
420 }
421 BTRFS_ATTR(static_feature, supported_sectorsizes,
422 	   supported_sectorsizes_show);
423 
424 static ssize_t acl_show(struct kobject *kobj, struct kobj_attribute *a, char *buf)
425 {
426 	return sysfs_emit(buf, "%d\n", IS_ENABLED(CONFIG_BTRFS_FS_POSIX_ACL));
427 }
428 BTRFS_ATTR(static_feature, acl, acl_show);
429 
430 static ssize_t temp_fsid_supported_show(struct kobject *kobj,
431 					struct kobj_attribute *a, char *buf)
432 {
433 	return sysfs_emit(buf, "0\n");
434 }
435 BTRFS_ATTR(static_feature, temp_fsid, temp_fsid_supported_show);
436 
437 /*
438  * Features which only depend on kernel version.
439  *
440  * These are listed in /sys/fs/btrfs/features along with
441  * btrfs_supported_feature_attrs.
442  */
443 static struct attribute *btrfs_supported_static_feature_attrs[] = {
444 	BTRFS_ATTR_PTR(static_feature, acl),
445 	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
446 	BTRFS_ATTR_PTR(static_feature, supported_checksums),
447 	BTRFS_ATTR_PTR(static_feature, send_stream_version),
448 	BTRFS_ATTR_PTR(static_feature, supported_rescue_options),
449 	BTRFS_ATTR_PTR(static_feature, supported_sectorsizes),
450 	BTRFS_ATTR_PTR(static_feature, temp_fsid),
451 	NULL
452 };
453 
454 static const struct attribute_group btrfs_static_feature_attr_group = {
455 	.name = "features",
456 	.attrs = btrfs_supported_static_feature_attrs,
457 };
458 
459 /*
460  * Discard statistics and tunables
461  */
462 #define discard_to_fs_info(_kobj)	to_fs_info(get_btrfs_kobj(_kobj))
463 
464 static ssize_t btrfs_discardable_bytes_show(struct kobject *kobj,
465 					    struct kobj_attribute *a,
466 					    char *buf)
467 {
468 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
469 
470 	return sysfs_emit(buf, "%lld\n",
471 			atomic64_read(&fs_info->discard_ctl.discardable_bytes));
472 }
473 BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
474 
475 static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
476 					      struct kobj_attribute *a,
477 					      char *buf)
478 {
479 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
480 
481 	return sysfs_emit(buf, "%d\n",
482 			atomic_read(&fs_info->discard_ctl.discardable_extents));
483 }
484 BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
485 
486 static ssize_t btrfs_discard_bitmap_bytes_show(struct kobject *kobj,
487 					       struct kobj_attribute *a,
488 					       char *buf)
489 {
490 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
491 
492 	return sysfs_emit(buf, "%llu\n",
493 			  fs_info->discard_ctl.discard_bitmap_bytes);
494 }
495 BTRFS_ATTR(discard, discard_bitmap_bytes, btrfs_discard_bitmap_bytes_show);
496 
497 static ssize_t btrfs_discard_bytes_saved_show(struct kobject *kobj,
498 					      struct kobj_attribute *a,
499 					      char *buf)
500 {
501 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
502 
503 	return sysfs_emit(buf, "%lld\n",
504 		atomic64_read(&fs_info->discard_ctl.discard_bytes_saved));
505 }
506 BTRFS_ATTR(discard, discard_bytes_saved, btrfs_discard_bytes_saved_show);
507 
508 static ssize_t btrfs_discard_extent_bytes_show(struct kobject *kobj,
509 					       struct kobj_attribute *a,
510 					       char *buf)
511 {
512 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
513 
514 	return sysfs_emit(buf, "%llu\n",
515 			  fs_info->discard_ctl.discard_extent_bytes);
516 }
517 BTRFS_ATTR(discard, discard_extent_bytes, btrfs_discard_extent_bytes_show);
518 
519 static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
520 					     struct kobj_attribute *a,
521 					     char *buf)
522 {
523 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
524 
525 	return sysfs_emit(buf, "%u\n",
526 			  READ_ONCE(fs_info->discard_ctl.iops_limit));
527 }
528 
529 static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
530 					      struct kobj_attribute *a,
531 					      const char *buf, size_t len)
532 {
533 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
534 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
535 	u32 iops_limit;
536 	int ret;
537 
538 	ret = kstrtou32(buf, 10, &iops_limit);
539 	if (ret)
540 		return -EINVAL;
541 
542 	WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
543 	btrfs_discard_calc_delay(discard_ctl);
544 	btrfs_discard_schedule_work(discard_ctl, true);
545 	return len;
546 }
547 BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
548 	      btrfs_discard_iops_limit_store);
549 
550 static ssize_t btrfs_discard_kbps_limit_show(struct kobject *kobj,
551 					     struct kobj_attribute *a,
552 					     char *buf)
553 {
554 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
555 
556 	return sysfs_emit(buf, "%u\n",
557 			  READ_ONCE(fs_info->discard_ctl.kbps_limit));
558 }
559 
560 static ssize_t btrfs_discard_kbps_limit_store(struct kobject *kobj,
561 					      struct kobj_attribute *a,
562 					      const char *buf, size_t len)
563 {
564 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
565 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
566 	u32 kbps_limit;
567 	int ret;
568 
569 	ret = kstrtou32(buf, 10, &kbps_limit);
570 	if (ret)
571 		return -EINVAL;
572 
573 	WRITE_ONCE(discard_ctl->kbps_limit, kbps_limit);
574 	btrfs_discard_schedule_work(discard_ctl, true);
575 	return len;
576 }
577 BTRFS_ATTR_RW(discard, kbps_limit, btrfs_discard_kbps_limit_show,
578 	      btrfs_discard_kbps_limit_store);
579 
580 static ssize_t btrfs_discard_max_discard_size_show(struct kobject *kobj,
581 						   struct kobj_attribute *a,
582 						   char *buf)
583 {
584 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
585 
586 	return sysfs_emit(buf, "%llu\n",
587 			  READ_ONCE(fs_info->discard_ctl.max_discard_size));
588 }
589 
590 static ssize_t btrfs_discard_max_discard_size_store(struct kobject *kobj,
591 						    struct kobj_attribute *a,
592 						    const char *buf, size_t len)
593 {
594 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
595 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
596 	u64 max_discard_size;
597 	int ret;
598 
599 	ret = kstrtou64(buf, 10, &max_discard_size);
600 	if (ret)
601 		return -EINVAL;
602 
603 	WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);
604 
605 	return len;
606 }
607 BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
608 	      btrfs_discard_max_discard_size_store);
609 
610 /*
611  * Per-filesystem stats for discard (when mounted with discard=async).
612  *
613  * Path: /sys/fs/btrfs/<uuid>/discard/
614  */
615 static const struct attribute *discard_attrs[] = {
616 	BTRFS_ATTR_PTR(discard, discardable_bytes),
617 	BTRFS_ATTR_PTR(discard, discardable_extents),
618 	BTRFS_ATTR_PTR(discard, discard_bitmap_bytes),
619 	BTRFS_ATTR_PTR(discard, discard_bytes_saved),
620 	BTRFS_ATTR_PTR(discard, discard_extent_bytes),
621 	BTRFS_ATTR_PTR(discard, iops_limit),
622 	BTRFS_ATTR_PTR(discard, kbps_limit),
623 	BTRFS_ATTR_PTR(discard, max_discard_size),
624 	NULL,
625 };
626 
627 #ifdef CONFIG_BTRFS_DEBUG
628 
629 /*
630  * Per-filesystem runtime debugging exported via sysfs.
631  *
632  * Path: /sys/fs/btrfs/UUID/debug/
633  */
634 static const struct attribute *btrfs_debug_mount_attrs[] = {
635 	NULL,
636 };
637 
638 /*
639  * Runtime debugging exported via sysfs, applies to all mounted filesystems.
640  *
641  * Path: /sys/fs/btrfs/debug
642  */
643 static struct attribute *btrfs_debug_feature_attrs[] = {
644 	NULL
645 };
646 
647 static const struct attribute_group btrfs_debug_feature_attr_group = {
648 	.name = "debug",
649 	.attrs = btrfs_debug_feature_attrs,
650 };
651 
652 #endif
653 
654 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
655 {
656 	u64 val;
657 	if (lock)
658 		spin_lock(lock);
659 	val = *value_ptr;
660 	if (lock)
661 		spin_unlock(lock);
662 	return sysfs_emit(buf, "%llu\n", val);
663 }
664 
665 static ssize_t global_rsv_size_show(struct kobject *kobj,
666 				    struct kobj_attribute *ka, char *buf)
667 {
668 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
669 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
670 	return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
671 }
672 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
673 
674 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
675 					struct kobj_attribute *a, char *buf)
676 {
677 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
678 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
679 	return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
680 }
681 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
682 
683 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
684 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
685 
686 static ssize_t raid_bytes_show(struct kobject *kobj,
687 			       struct kobj_attribute *attr, char *buf);
688 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
689 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
690 
691 static ssize_t raid_bytes_show(struct kobject *kobj,
692 			       struct kobj_attribute *attr, char *buf)
693 
694 {
695 	struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
696 	struct btrfs_block_group *block_group;
697 	int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
698 	u64 val = 0;
699 
700 	down_read(&sinfo->groups_sem);
701 	list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
702 		if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
703 			val += block_group->length;
704 		else
705 			val += block_group->used;
706 	}
707 	up_read(&sinfo->groups_sem);
708 	return sysfs_emit(buf, "%llu\n", val);
709 }
710 
711 /*
712  * Allocation information about block group profiles.
713  *
714  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>/
715  */
716 static struct attribute *raid_attrs[] = {
717 	BTRFS_ATTR_PTR(raid, total_bytes),
718 	BTRFS_ATTR_PTR(raid, used_bytes),
719 	NULL
720 };
721 ATTRIBUTE_GROUPS(raid);
722 
723 static void release_raid_kobj(struct kobject *kobj)
724 {
725 	kfree(to_raid_kobj(kobj));
726 }
727 
728 static const struct kobj_type btrfs_raid_ktype = {
729 	.sysfs_ops = &kobj_sysfs_ops,
730 	.release = release_raid_kobj,
731 	.default_groups = raid_groups,
732 };
733 
734 #define SPACE_INFO_ATTR(field)						\
735 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,	\
736 					     struct kobj_attribute *a,	\
737 					     char *buf)			\
738 {									\
739 	struct btrfs_space_info *sinfo = to_space_info(kobj);		\
740 	return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);	\
741 }									\
742 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
743 
744 static ssize_t btrfs_chunk_size_show(struct kobject *kobj,
745 				     struct kobj_attribute *a, char *buf)
746 {
747 	struct btrfs_space_info *sinfo = to_space_info(kobj);
748 
749 	return sysfs_emit(buf, "%llu\n", READ_ONCE(sinfo->chunk_size));
750 }
751 
752 /*
753  * Store new chunk size in space info. Can be called on a read-only filesystem.
754  *
755  * If the new chunk size value is larger than 10% of free space it is reduced
756  * to match that limit. Alignment must be to 256M and the system chunk size
757  * cannot be set.
758  */
759 static ssize_t btrfs_chunk_size_store(struct kobject *kobj,
760 				      struct kobj_attribute *a,
761 				      const char *buf, size_t len)
762 {
763 	struct btrfs_space_info *space_info = to_space_info(kobj);
764 	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
765 	char *retptr;
766 	u64 val;
767 
768 	if (!capable(CAP_SYS_ADMIN))
769 		return -EPERM;
770 
771 	if (!fs_info->fs_devices)
772 		return -EINVAL;
773 
774 	if (btrfs_is_zoned(fs_info))
775 		return -EINVAL;
776 
777 	/* System block type must not be changed. */
778 	if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
779 		return -EPERM;
780 
781 	val = memparse(buf, &retptr);
782 	/* There could be trailing '\n', also catch any typos after the value */
783 	retptr = skip_spaces(retptr);
784 	if (*retptr != 0 || val == 0)
785 		return -EINVAL;
786 
787 	val = min(val, BTRFS_MAX_DATA_CHUNK_SIZE);
788 
789 	/* Limit stripe size to 10% of available space. */
790 	val = min(mult_perc(fs_info->fs_devices->total_rw_bytes, 10), val);
791 
792 	/* Must be multiple of 256M. */
793 	val &= ~((u64)SZ_256M - 1);
794 
795 	/* Must be at least 256M. */
796 	if (val < SZ_256M)
797 		return -EINVAL;
798 
799 	btrfs_update_space_info_chunk_size(space_info, val);
800 
801 	return len;
802 }
803 
804 static ssize_t btrfs_size_classes_show(struct kobject *kobj,
805 				       struct kobj_attribute *a, char *buf)
806 {
807 	struct btrfs_space_info *sinfo = to_space_info(kobj);
808 	struct btrfs_block_group *bg;
809 	u32 none = 0;
810 	u32 small = 0;
811 	u32 medium = 0;
812 	u32 large = 0;
813 
814 	for (int i = 0; i < BTRFS_NR_RAID_TYPES; ++i) {
815 		down_read(&sinfo->groups_sem);
816 		list_for_each_entry(bg, &sinfo->block_groups[i], list) {
817 			if (!btrfs_block_group_should_use_size_class(bg))
818 				continue;
819 			switch (bg->size_class) {
820 			case BTRFS_BG_SZ_NONE:
821 				none++;
822 				break;
823 			case BTRFS_BG_SZ_SMALL:
824 				small++;
825 				break;
826 			case BTRFS_BG_SZ_MEDIUM:
827 				medium++;
828 				break;
829 			case BTRFS_BG_SZ_LARGE:
830 				large++;
831 				break;
832 			}
833 		}
834 		up_read(&sinfo->groups_sem);
835 	}
836 	return sysfs_emit(buf, "none %u\n"
837 			       "small %u\n"
838 			       "medium %u\n"
839 			       "large %u\n",
840 			       none, small, medium, large);
841 }
842 
843 #ifdef CONFIG_BTRFS_DEBUG
844 /*
845  * Request chunk allocation with current chunk size.
846  */
847 static ssize_t btrfs_force_chunk_alloc_store(struct kobject *kobj,
848 					     struct kobj_attribute *a,
849 					     const char *buf, size_t len)
850 {
851 	struct btrfs_space_info *space_info = to_space_info(kobj);
852 	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
853 	struct btrfs_trans_handle *trans;
854 	bool val;
855 	int ret;
856 
857 	if (!capable(CAP_SYS_ADMIN))
858 		return -EPERM;
859 
860 	if (sb_rdonly(fs_info->sb))
861 		return -EROFS;
862 
863 	ret = kstrtobool(buf, &val);
864 	if (ret)
865 		return ret;
866 
867 	if (!val)
868 		return -EINVAL;
869 
870 	/*
871 	 * This is unsafe to be called from sysfs context and may cause
872 	 * unexpected problems.
873 	 */
874 	trans = btrfs_start_transaction(fs_info->tree_root, 0);
875 	if (IS_ERR(trans))
876 		return PTR_ERR(trans);
877 	ret = btrfs_force_chunk_alloc(trans, space_info->flags);
878 	btrfs_end_transaction(trans);
879 
880 	if (ret == 1)
881 		return len;
882 
883 	return -ENOSPC;
884 }
885 BTRFS_ATTR_W(space_info, force_chunk_alloc, btrfs_force_chunk_alloc_store);
886 
887 #endif
888 
889 SPACE_INFO_ATTR(flags);
890 SPACE_INFO_ATTR(total_bytes);
891 SPACE_INFO_ATTR(bytes_used);
892 SPACE_INFO_ATTR(bytes_pinned);
893 SPACE_INFO_ATTR(bytes_reserved);
894 SPACE_INFO_ATTR(bytes_may_use);
895 SPACE_INFO_ATTR(bytes_readonly);
896 SPACE_INFO_ATTR(bytes_zone_unusable);
897 SPACE_INFO_ATTR(disk_used);
898 SPACE_INFO_ATTR(disk_total);
899 SPACE_INFO_ATTR(reclaim_count);
900 SPACE_INFO_ATTR(reclaim_bytes);
901 SPACE_INFO_ATTR(reclaim_errors);
902 BTRFS_ATTR_RW(space_info, chunk_size, btrfs_chunk_size_show, btrfs_chunk_size_store);
903 BTRFS_ATTR(space_info, size_classes, btrfs_size_classes_show);
904 
905 static ssize_t btrfs_sinfo_bg_reclaim_threshold_show(struct kobject *kobj,
906 						     struct kobj_attribute *a,
907 						     char *buf)
908 {
909 	struct btrfs_space_info *space_info = to_space_info(kobj);
910 	ssize_t ret;
911 
912 	spin_lock(&space_info->lock);
913 	ret = sysfs_emit(buf, "%d\n", btrfs_calc_reclaim_threshold(space_info));
914 	spin_unlock(&space_info->lock);
915 	return ret;
916 }
917 
918 static ssize_t btrfs_sinfo_bg_reclaim_threshold_store(struct kobject *kobj,
919 						      struct kobj_attribute *a,
920 						      const char *buf, size_t len)
921 {
922 	struct btrfs_space_info *space_info = to_space_info(kobj);
923 	int thresh;
924 	int ret;
925 
926 	if (READ_ONCE(space_info->dynamic_reclaim))
927 		return -EINVAL;
928 
929 	ret = kstrtoint(buf, 10, &thresh);
930 	if (ret)
931 		return ret;
932 
933 	if (thresh < 0 || thresh > 100)
934 		return -EINVAL;
935 
936 	WRITE_ONCE(space_info->bg_reclaim_threshold, thresh);
937 
938 	return len;
939 }
940 
941 BTRFS_ATTR_RW(space_info, bg_reclaim_threshold,
942 	      btrfs_sinfo_bg_reclaim_threshold_show,
943 	      btrfs_sinfo_bg_reclaim_threshold_store);
944 
945 static ssize_t btrfs_sinfo_dynamic_reclaim_show(struct kobject *kobj,
946 						struct kobj_attribute *a,
947 						char *buf)
948 {
949 	struct btrfs_space_info *space_info = to_space_info(kobj);
950 
951 	return sysfs_emit(buf, "%d\n", READ_ONCE(space_info->dynamic_reclaim));
952 }
953 
954 static ssize_t btrfs_sinfo_dynamic_reclaim_store(struct kobject *kobj,
955 						 struct kobj_attribute *a,
956 						 const char *buf, size_t len)
957 {
958 	struct btrfs_space_info *space_info = to_space_info(kobj);
959 	int dynamic_reclaim;
960 	int ret;
961 
962 	ret = kstrtoint(buf, 10, &dynamic_reclaim);
963 	if (ret)
964 		return ret;
965 
966 	if (dynamic_reclaim < 0)
967 		return -EINVAL;
968 
969 	WRITE_ONCE(space_info->dynamic_reclaim, dynamic_reclaim != 0);
970 
971 	return len;
972 }
973 
974 BTRFS_ATTR_RW(space_info, dynamic_reclaim,
975 	      btrfs_sinfo_dynamic_reclaim_show,
976 	      btrfs_sinfo_dynamic_reclaim_store);
977 
978 static ssize_t btrfs_sinfo_periodic_reclaim_show(struct kobject *kobj,
979 						struct kobj_attribute *a,
980 						char *buf)
981 {
982 	struct btrfs_space_info *space_info = to_space_info(kobj);
983 
984 	return sysfs_emit(buf, "%d\n", READ_ONCE(space_info->periodic_reclaim));
985 }
986 
987 static ssize_t btrfs_sinfo_periodic_reclaim_store(struct kobject *kobj,
988 						 struct kobj_attribute *a,
989 						 const char *buf, size_t len)
990 {
991 	struct btrfs_space_info *space_info = to_space_info(kobj);
992 	int periodic_reclaim;
993 	int ret;
994 
995 	ret = kstrtoint(buf, 10, &periodic_reclaim);
996 	if (ret)
997 		return ret;
998 
999 	if (periodic_reclaim < 0)
1000 		return -EINVAL;
1001 
1002 	WRITE_ONCE(space_info->periodic_reclaim, periodic_reclaim != 0);
1003 
1004 	return len;
1005 }
1006 
1007 BTRFS_ATTR_RW(space_info, periodic_reclaim,
1008 	      btrfs_sinfo_periodic_reclaim_show,
1009 	      btrfs_sinfo_periodic_reclaim_store);
1010 
1011 /*
1012  * Allocation information about block group types.
1013  *
1014  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/
1015  */
1016 static struct attribute *space_info_attrs[] = {
1017 	BTRFS_ATTR_PTR(space_info, flags),
1018 	BTRFS_ATTR_PTR(space_info, total_bytes),
1019 	BTRFS_ATTR_PTR(space_info, bytes_used),
1020 	BTRFS_ATTR_PTR(space_info, bytes_pinned),
1021 	BTRFS_ATTR_PTR(space_info, bytes_reserved),
1022 	BTRFS_ATTR_PTR(space_info, bytes_may_use),
1023 	BTRFS_ATTR_PTR(space_info, bytes_readonly),
1024 	BTRFS_ATTR_PTR(space_info, bytes_zone_unusable),
1025 	BTRFS_ATTR_PTR(space_info, disk_used),
1026 	BTRFS_ATTR_PTR(space_info, disk_total),
1027 	BTRFS_ATTR_PTR(space_info, bg_reclaim_threshold),
1028 	BTRFS_ATTR_PTR(space_info, dynamic_reclaim),
1029 	BTRFS_ATTR_PTR(space_info, chunk_size),
1030 	BTRFS_ATTR_PTR(space_info, size_classes),
1031 	BTRFS_ATTR_PTR(space_info, reclaim_count),
1032 	BTRFS_ATTR_PTR(space_info, reclaim_bytes),
1033 	BTRFS_ATTR_PTR(space_info, reclaim_errors),
1034 	BTRFS_ATTR_PTR(space_info, periodic_reclaim),
1035 #ifdef CONFIG_BTRFS_DEBUG
1036 	BTRFS_ATTR_PTR(space_info, force_chunk_alloc),
1037 #endif
1038 	NULL,
1039 };
1040 ATTRIBUTE_GROUPS(space_info);
1041 
1042 static void space_info_release(struct kobject *kobj)
1043 {
1044 	struct btrfs_space_info *sinfo = to_space_info(kobj);
1045 	kfree(sinfo);
1046 }
1047 
1048 static const struct kobj_type space_info_ktype = {
1049 	.sysfs_ops = &kobj_sysfs_ops,
1050 	.release = space_info_release,
1051 	.default_groups = space_info_groups,
1052 };
1053 
1054 /*
1055  * Allocation information about block groups.
1056  *
1057  * Path: /sys/fs/btrfs/<uuid>/allocation/
1058  */
1059 static const struct attribute *allocation_attrs[] = {
1060 	BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
1061 	BTRFS_ATTR_PTR(allocation, global_rsv_size),
1062 	NULL,
1063 };
1064 
1065 static ssize_t btrfs_label_show(struct kobject *kobj,
1066 				struct kobj_attribute *a, char *buf)
1067 {
1068 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1069 	char *label = fs_info->super_copy->label;
1070 	ssize_t ret;
1071 
1072 	spin_lock(&fs_info->super_lock);
1073 	ret = sysfs_emit(buf, label[0] ? "%s\n" : "%s", label);
1074 	spin_unlock(&fs_info->super_lock);
1075 
1076 	return ret;
1077 }
1078 
1079 static ssize_t btrfs_label_store(struct kobject *kobj,
1080 				 struct kobj_attribute *a,
1081 				 const char *buf, size_t len)
1082 {
1083 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1084 	size_t p_len;
1085 
1086 	if (!fs_info)
1087 		return -EPERM;
1088 
1089 	if (sb_rdonly(fs_info->sb))
1090 		return -EROFS;
1091 
1092 	/*
1093 	 * p_len is the len until the first occurrence of either
1094 	 * '\n' or '\0'
1095 	 */
1096 	p_len = strcspn(buf, "\n");
1097 
1098 	if (p_len >= BTRFS_LABEL_SIZE)
1099 		return -EINVAL;
1100 
1101 	spin_lock(&fs_info->super_lock);
1102 	memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
1103 	memcpy(fs_info->super_copy->label, buf, p_len);
1104 	spin_unlock(&fs_info->super_lock);
1105 
1106 	/*
1107 	 * We don't want to do full transaction commit from inside sysfs
1108 	 */
1109 	set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
1110 	wake_up_process(fs_info->transaction_kthread);
1111 
1112 	return len;
1113 }
1114 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
1115 
1116 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
1117 				struct kobj_attribute *a, char *buf)
1118 {
1119 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1120 
1121 	return sysfs_emit(buf, "%u\n", fs_info->super_copy->nodesize);
1122 }
1123 
1124 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
1125 
1126 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
1127 				struct kobj_attribute *a, char *buf)
1128 {
1129 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1130 
1131 	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
1132 }
1133 
1134 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
1135 
1136 static ssize_t btrfs_commit_stats_show(struct kobject *kobj,
1137 				       struct kobj_attribute *a, char *buf)
1138 {
1139 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1140 
1141 	return sysfs_emit(buf,
1142 		"commits %llu\n"
1143 		"last_commit_ms %llu\n"
1144 		"max_commit_ms %llu\n"
1145 		"total_commit_ms %llu\n",
1146 		fs_info->commit_stats.commit_count,
1147 		div_u64(fs_info->commit_stats.last_commit_dur, NSEC_PER_MSEC),
1148 		div_u64(fs_info->commit_stats.max_commit_dur, NSEC_PER_MSEC),
1149 		div_u64(fs_info->commit_stats.total_commit_dur, NSEC_PER_MSEC));
1150 }
1151 
1152 static ssize_t btrfs_commit_stats_store(struct kobject *kobj,
1153 					struct kobj_attribute *a,
1154 					const char *buf, size_t len)
1155 {
1156 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1157 	unsigned long val;
1158 	int ret;
1159 
1160 	if (!fs_info)
1161 		return -EPERM;
1162 
1163 	if (!capable(CAP_SYS_RESOURCE))
1164 		return -EPERM;
1165 
1166 	ret = kstrtoul(buf, 10, &val);
1167 	if (ret)
1168 		return ret;
1169 	if (val)
1170 		return -EINVAL;
1171 
1172 	WRITE_ONCE(fs_info->commit_stats.max_commit_dur, 0);
1173 
1174 	return len;
1175 }
1176 BTRFS_ATTR_RW(, commit_stats, btrfs_commit_stats_show, btrfs_commit_stats_store);
1177 
1178 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
1179 				struct kobj_attribute *a, char *buf)
1180 {
1181 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1182 
1183 	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
1184 }
1185 
1186 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
1187 
1188 static ssize_t quota_override_show(struct kobject *kobj,
1189 				   struct kobj_attribute *a, char *buf)
1190 {
1191 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1192 	int quota_override;
1193 
1194 	quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1195 	return sysfs_emit(buf, "%d\n", quota_override);
1196 }
1197 
1198 static ssize_t quota_override_store(struct kobject *kobj,
1199 				    struct kobj_attribute *a,
1200 				    const char *buf, size_t len)
1201 {
1202 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1203 	unsigned long knob;
1204 	int err;
1205 
1206 	if (!fs_info)
1207 		return -EPERM;
1208 
1209 	if (!capable(CAP_SYS_RESOURCE))
1210 		return -EPERM;
1211 
1212 	err = kstrtoul(buf, 10, &knob);
1213 	if (err)
1214 		return err;
1215 	if (knob > 1)
1216 		return -EINVAL;
1217 
1218 	if (knob)
1219 		set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1220 	else
1221 		clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1222 
1223 	return len;
1224 }
1225 
1226 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
1227 
1228 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
1229 				struct kobj_attribute *a, char *buf)
1230 {
1231 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1232 
1233 	return sysfs_emit(buf, "%pU\n", fs_info->fs_devices->metadata_uuid);
1234 }
1235 
1236 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
1237 
1238 static ssize_t btrfs_checksum_show(struct kobject *kobj,
1239 				   struct kobj_attribute *a, char *buf)
1240 {
1241 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1242 	u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
1243 
1244 	return sysfs_emit(buf, "%s (%s)\n",
1245 			  btrfs_super_csum_name(csum_type),
1246 			  crypto_shash_driver_name(fs_info->csum_shash));
1247 }
1248 
1249 BTRFS_ATTR(, checksum, btrfs_checksum_show);
1250 
1251 static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
1252 		struct kobj_attribute *a, char *buf)
1253 {
1254 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1255 	const char *str;
1256 
1257 	switch (READ_ONCE(fs_info->exclusive_operation)) {
1258 		case  BTRFS_EXCLOP_NONE:
1259 			str = "none\n";
1260 			break;
1261 		case BTRFS_EXCLOP_BALANCE:
1262 			str = "balance\n";
1263 			break;
1264 		case BTRFS_EXCLOP_BALANCE_PAUSED:
1265 			str = "balance paused\n";
1266 			break;
1267 		case BTRFS_EXCLOP_DEV_ADD:
1268 			str = "device add\n";
1269 			break;
1270 		case BTRFS_EXCLOP_DEV_REMOVE:
1271 			str = "device remove\n";
1272 			break;
1273 		case BTRFS_EXCLOP_DEV_REPLACE:
1274 			str = "device replace\n";
1275 			break;
1276 		case BTRFS_EXCLOP_RESIZE:
1277 			str = "resize\n";
1278 			break;
1279 		case BTRFS_EXCLOP_SWAP_ACTIVATE:
1280 			str = "swap activate\n";
1281 			break;
1282 		default:
1283 			str = "UNKNOWN\n";
1284 			break;
1285 	}
1286 	return sysfs_emit(buf, "%s", str);
1287 }
1288 BTRFS_ATTR(, exclusive_operation, btrfs_exclusive_operation_show);
1289 
1290 static ssize_t btrfs_generation_show(struct kobject *kobj,
1291 				     struct kobj_attribute *a, char *buf)
1292 {
1293 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1294 
1295 	return sysfs_emit(buf, "%llu\n", btrfs_get_fs_generation(fs_info));
1296 }
1297 BTRFS_ATTR(, generation, btrfs_generation_show);
1298 
1299 static ssize_t btrfs_temp_fsid_show(struct kobject *kobj,
1300 				    struct kobj_attribute *a, char *buf)
1301 {
1302 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1303 
1304 	return sysfs_emit(buf, "%d\n", fs_info->fs_devices->temp_fsid);
1305 }
1306 BTRFS_ATTR(, temp_fsid, btrfs_temp_fsid_show);
1307 
1308 static const char * const btrfs_read_policy_name[] = { "pid" };
1309 
1310 static ssize_t btrfs_read_policy_show(struct kobject *kobj,
1311 				      struct kobj_attribute *a, char *buf)
1312 {
1313 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1314 	const enum btrfs_read_policy policy = READ_ONCE(fs_devices->read_policy);
1315 	ssize_t ret = 0;
1316 	int i;
1317 
1318 	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1319 		if (policy == i)
1320 			ret += sysfs_emit_at(buf, ret, "%s[%s]",
1321 					 (ret == 0 ? "" : " "),
1322 					 btrfs_read_policy_name[i]);
1323 		else
1324 			ret += sysfs_emit_at(buf, ret, "%s%s",
1325 					 (ret == 0 ? "" : " "),
1326 					 btrfs_read_policy_name[i]);
1327 	}
1328 
1329 	ret += sysfs_emit_at(buf, ret, "\n");
1330 
1331 	return ret;
1332 }
1333 
1334 static ssize_t btrfs_read_policy_store(struct kobject *kobj,
1335 				       struct kobj_attribute *a,
1336 				       const char *buf, size_t len)
1337 {
1338 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1339 	int i;
1340 
1341 	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1342 		if (sysfs_streq(buf, btrfs_read_policy_name[i])) {
1343 			if (i != READ_ONCE(fs_devices->read_policy)) {
1344 				WRITE_ONCE(fs_devices->read_policy, i);
1345 				btrfs_info(fs_devices->fs_info,
1346 					   "read policy set to '%s'",
1347 					   btrfs_read_policy_name[i]);
1348 			}
1349 			return len;
1350 		}
1351 	}
1352 
1353 	return -EINVAL;
1354 }
1355 BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store);
1356 
1357 static ssize_t btrfs_bg_reclaim_threshold_show(struct kobject *kobj,
1358 					       struct kobj_attribute *a,
1359 					       char *buf)
1360 {
1361 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1362 
1363 	return sysfs_emit(buf, "%d\n", READ_ONCE(fs_info->bg_reclaim_threshold));
1364 }
1365 
1366 static ssize_t btrfs_bg_reclaim_threshold_store(struct kobject *kobj,
1367 						struct kobj_attribute *a,
1368 						const char *buf, size_t len)
1369 {
1370 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1371 	int thresh;
1372 	int ret;
1373 
1374 	ret = kstrtoint(buf, 10, &thresh);
1375 	if (ret)
1376 		return ret;
1377 
1378 #ifdef CONFIG_BTRFS_DEBUG
1379 	if (thresh != 0 && (thresh > 100))
1380 		return -EINVAL;
1381 #else
1382 	if (thresh != 0 && (thresh <= 50 || thresh > 100))
1383 		return -EINVAL;
1384 #endif
1385 
1386 	WRITE_ONCE(fs_info->bg_reclaim_threshold, thresh);
1387 
1388 	return len;
1389 }
1390 BTRFS_ATTR_RW(, bg_reclaim_threshold, btrfs_bg_reclaim_threshold_show,
1391 	      btrfs_bg_reclaim_threshold_store);
1392 
1393 #ifdef CONFIG_BTRFS_DEBUG
1394 static ssize_t btrfs_offload_csum_show(struct kobject *kobj,
1395 				       struct kobj_attribute *a, char *buf)
1396 {
1397 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1398 
1399 	switch (READ_ONCE(fs_devices->offload_csum_mode)) {
1400 	case BTRFS_OFFLOAD_CSUM_AUTO:
1401 		return sysfs_emit(buf, "auto\n");
1402 	case BTRFS_OFFLOAD_CSUM_FORCE_ON:
1403 		return sysfs_emit(buf, "1\n");
1404 	case BTRFS_OFFLOAD_CSUM_FORCE_OFF:
1405 		return sysfs_emit(buf, "0\n");
1406 	default:
1407 		WARN_ON(1);
1408 		return -EINVAL;
1409 	}
1410 }
1411 
1412 static ssize_t btrfs_offload_csum_store(struct kobject *kobj,
1413 					struct kobj_attribute *a, const char *buf,
1414 					size_t len)
1415 {
1416 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1417 	int ret;
1418 	bool val;
1419 
1420 	ret = kstrtobool(buf, &val);
1421 	if (ret == 0)
1422 		WRITE_ONCE(fs_devices->offload_csum_mode,
1423 			   val ? BTRFS_OFFLOAD_CSUM_FORCE_ON : BTRFS_OFFLOAD_CSUM_FORCE_OFF);
1424 	else if (ret == -EINVAL && sysfs_streq(buf, "auto"))
1425 		WRITE_ONCE(fs_devices->offload_csum_mode, BTRFS_OFFLOAD_CSUM_AUTO);
1426 	else
1427 		return -EINVAL;
1428 
1429 	return len;
1430 }
1431 BTRFS_ATTR_RW(, offload_csum, btrfs_offload_csum_show, btrfs_offload_csum_store);
1432 #endif
1433 
1434 /*
1435  * Per-filesystem information and stats.
1436  *
1437  * Path: /sys/fs/btrfs/<uuid>/
1438  */
1439 static const struct attribute *btrfs_attrs[] = {
1440 	BTRFS_ATTR_PTR(, label),
1441 	BTRFS_ATTR_PTR(, nodesize),
1442 	BTRFS_ATTR_PTR(, sectorsize),
1443 	BTRFS_ATTR_PTR(, clone_alignment),
1444 	BTRFS_ATTR_PTR(, quota_override),
1445 	BTRFS_ATTR_PTR(, metadata_uuid),
1446 	BTRFS_ATTR_PTR(, checksum),
1447 	BTRFS_ATTR_PTR(, exclusive_operation),
1448 	BTRFS_ATTR_PTR(, generation),
1449 	BTRFS_ATTR_PTR(, read_policy),
1450 	BTRFS_ATTR_PTR(, bg_reclaim_threshold),
1451 	BTRFS_ATTR_PTR(, commit_stats),
1452 	BTRFS_ATTR_PTR(, temp_fsid),
1453 #ifdef CONFIG_BTRFS_DEBUG
1454 	BTRFS_ATTR_PTR(, offload_csum),
1455 #endif
1456 	NULL,
1457 };
1458 
1459 static void btrfs_release_fsid_kobj(struct kobject *kobj)
1460 {
1461 	struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
1462 
1463 	memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
1464 	complete(&fs_devs->kobj_unregister);
1465 }
1466 
1467 static const struct kobj_type btrfs_ktype = {
1468 	.sysfs_ops	= &kobj_sysfs_ops,
1469 	.release	= btrfs_release_fsid_kobj,
1470 };
1471 
1472 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
1473 {
1474 	if (kobj->ktype != &btrfs_ktype)
1475 		return NULL;
1476 	return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
1477 }
1478 
1479 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
1480 {
1481 	if (kobj->ktype != &btrfs_ktype)
1482 		return NULL;
1483 	return to_fs_devs(kobj)->fs_info;
1484 }
1485 
1486 static struct kobject *get_btrfs_kobj(struct kobject *kobj)
1487 {
1488 	while (kobj) {
1489 		if (kobj->ktype == &btrfs_ktype)
1490 			return kobj;
1491 		kobj = kobj->parent;
1492 	}
1493 	return NULL;
1494 }
1495 
1496 #define NUM_FEATURE_BITS 64
1497 #define BTRFS_FEATURE_NAME_MAX 13
1498 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
1499 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
1500 
1501 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names) ==
1502 	      ARRAY_SIZE(btrfs_feature_attrs));
1503 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names[0]) ==
1504 	      ARRAY_SIZE(btrfs_feature_attrs[0]));
1505 
1506 static const u64 supported_feature_masks[FEAT_MAX] = {
1507 	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
1508 	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
1509 	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
1510 };
1511 
1512 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
1513 {
1514 	int set;
1515 
1516 	for (set = 0; set < FEAT_MAX; set++) {
1517 		int i;
1518 		struct attribute *attrs[2];
1519 		struct attribute_group agroup = {
1520 			.name = "features",
1521 			.attrs = attrs,
1522 		};
1523 		u64 features = get_features(fs_info, set);
1524 		features &= ~supported_feature_masks[set];
1525 
1526 		if (!features)
1527 			continue;
1528 
1529 		attrs[1] = NULL;
1530 		for (i = 0; i < NUM_FEATURE_BITS; i++) {
1531 			struct btrfs_feature_attr *fa;
1532 
1533 			if (!(features & (1ULL << i)))
1534 				continue;
1535 
1536 			fa = &btrfs_feature_attrs[set][i];
1537 			attrs[0] = &fa->kobj_attr.attr;
1538 			if (add) {
1539 				int ret;
1540 				ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
1541 							&agroup);
1542 				if (ret)
1543 					return ret;
1544 			} else
1545 				sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
1546 						    &agroup);
1547 		}
1548 
1549 	}
1550 	return 0;
1551 }
1552 
1553 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1554 {
1555 	if (fs_devs->devinfo_kobj) {
1556 		kobject_del(fs_devs->devinfo_kobj);
1557 		kobject_put(fs_devs->devinfo_kobj);
1558 		fs_devs->devinfo_kobj = NULL;
1559 	}
1560 
1561 	if (fs_devs->devices_kobj) {
1562 		kobject_del(fs_devs->devices_kobj);
1563 		kobject_put(fs_devs->devices_kobj);
1564 		fs_devs->devices_kobj = NULL;
1565 	}
1566 
1567 	if (fs_devs->fsid_kobj.state_initialized) {
1568 		kobject_del(&fs_devs->fsid_kobj);
1569 		kobject_put(&fs_devs->fsid_kobj);
1570 		wait_for_completion(&fs_devs->kobj_unregister);
1571 	}
1572 }
1573 
1574 /* when fs_devs is NULL it will remove all fsid kobject */
1575 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1576 {
1577 	struct list_head *fs_uuids = btrfs_get_fs_uuids();
1578 
1579 	if (fs_devs) {
1580 		__btrfs_sysfs_remove_fsid(fs_devs);
1581 		return;
1582 	}
1583 
1584 	list_for_each_entry(fs_devs, fs_uuids, fs_list) {
1585 		__btrfs_sysfs_remove_fsid(fs_devs);
1586 	}
1587 }
1588 
1589 static void btrfs_sysfs_remove_fs_devices(struct btrfs_fs_devices *fs_devices)
1590 {
1591 	struct btrfs_device *device;
1592 	struct btrfs_fs_devices *seed;
1593 
1594 	list_for_each_entry(device, &fs_devices->devices, dev_list)
1595 		btrfs_sysfs_remove_device(device);
1596 
1597 	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1598 		list_for_each_entry(device, &seed->devices, dev_list)
1599 			btrfs_sysfs_remove_device(device);
1600 	}
1601 }
1602 
1603 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
1604 {
1605 	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1606 
1607 	sysfs_remove_link(fsid_kobj, "bdi");
1608 
1609 	if (fs_info->space_info_kobj) {
1610 		sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
1611 		kobject_del(fs_info->space_info_kobj);
1612 		kobject_put(fs_info->space_info_kobj);
1613 	}
1614 	if (fs_info->discard_kobj) {
1615 		sysfs_remove_files(fs_info->discard_kobj, discard_attrs);
1616 		kobject_del(fs_info->discard_kobj);
1617 		kobject_put(fs_info->discard_kobj);
1618 	}
1619 #ifdef CONFIG_BTRFS_DEBUG
1620 	if (fs_info->debug_kobj) {
1621 		sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1622 		kobject_del(fs_info->debug_kobj);
1623 		kobject_put(fs_info->debug_kobj);
1624 	}
1625 #endif
1626 	addrm_unknown_feature_attrs(fs_info, false);
1627 	sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1628 	sysfs_remove_files(fsid_kobj, btrfs_attrs);
1629 	btrfs_sysfs_remove_fs_devices(fs_info->fs_devices);
1630 }
1631 
1632 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
1633 	[FEAT_COMPAT]	 = "compat",
1634 	[FEAT_COMPAT_RO] = "compat_ro",
1635 	[FEAT_INCOMPAT]	 = "incompat",
1636 };
1637 
1638 const char *btrfs_feature_set_name(enum btrfs_feature_set set)
1639 {
1640 	return btrfs_feature_set_names[set];
1641 }
1642 
1643 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
1644 {
1645 	size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
1646 	int len = 0;
1647 	int i;
1648 	char *str;
1649 
1650 	str = kmalloc(bufsize, GFP_KERNEL);
1651 	if (!str)
1652 		return str;
1653 
1654 	for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1655 		const char *name;
1656 
1657 		if (!(flags & (1ULL << i)))
1658 			continue;
1659 
1660 		name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
1661 		len += scnprintf(str + len, bufsize - len, "%s%s",
1662 				len ? "," : "", name);
1663 	}
1664 
1665 	return str;
1666 }
1667 
1668 static void init_feature_attrs(void)
1669 {
1670 	struct btrfs_feature_attr *fa;
1671 	int set, i;
1672 
1673 	memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
1674 	memset(btrfs_unknown_feature_names, 0,
1675 	       sizeof(btrfs_unknown_feature_names));
1676 
1677 	for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
1678 		struct btrfs_feature_attr *sfa;
1679 		struct attribute *a = btrfs_supported_feature_attrs[i];
1680 		int bit;
1681 		sfa = attr_to_btrfs_feature_attr(a);
1682 		bit = ilog2(sfa->feature_bit);
1683 		fa = &btrfs_feature_attrs[sfa->feature_set][bit];
1684 
1685 		fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
1686 	}
1687 
1688 	for (set = 0; set < FEAT_MAX; set++) {
1689 		for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1690 			char *name = btrfs_unknown_feature_names[set][i];
1691 			fa = &btrfs_feature_attrs[set][i];
1692 
1693 			if (fa->kobj_attr.attr.name)
1694 				continue;
1695 
1696 			snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
1697 				 btrfs_feature_set_names[set], i);
1698 
1699 			fa->kobj_attr.attr.name = name;
1700 			fa->kobj_attr.attr.mode = S_IRUGO;
1701 			fa->feature_set = set;
1702 			fa->feature_bit = 1ULL << i;
1703 		}
1704 	}
1705 }
1706 
1707 /*
1708  * Create a sysfs entry for a given block group type at path
1709  * /sys/fs/btrfs/UUID/allocation/data/TYPE
1710  */
1711 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
1712 {
1713 	struct btrfs_fs_info *fs_info = cache->fs_info;
1714 	struct btrfs_space_info *space_info = cache->space_info;
1715 	struct raid_kobject *rkobj;
1716 	const int index = btrfs_bg_flags_to_raid_index(cache->flags);
1717 	unsigned int nofs_flag;
1718 	int ret;
1719 
1720 	/*
1721 	 * Setup a NOFS context because kobject_add(), deep in its call chain,
1722 	 * does GFP_KERNEL allocations, and we are often called in a context
1723 	 * where if reclaim is triggered we can deadlock (we are either holding
1724 	 * a transaction handle or some lock required for a transaction
1725 	 * commit).
1726 	 */
1727 	nofs_flag = memalloc_nofs_save();
1728 
1729 	rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
1730 	if (!rkobj) {
1731 		memalloc_nofs_restore(nofs_flag);
1732 		btrfs_warn(cache->fs_info,
1733 				"couldn't alloc memory for raid level kobject");
1734 		return;
1735 	}
1736 
1737 	rkobj->flags = cache->flags;
1738 	kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
1739 
1740 	/*
1741 	 * We call this either on mount, or if we've created a block group for a
1742 	 * new index type while running (i.e. when restriping).  The running
1743 	 * case is tricky because we could race with other threads, so we need
1744 	 * to have this check to make sure we didn't already init the kobject.
1745 	 *
1746 	 * We don't have to protect on the free side because it only happens on
1747 	 * unmount.
1748 	 */
1749 	spin_lock(&space_info->lock);
1750 	if (space_info->block_group_kobjs[index]) {
1751 		spin_unlock(&space_info->lock);
1752 		kobject_put(&rkobj->kobj);
1753 		return;
1754 	} else {
1755 		space_info->block_group_kobjs[index] = &rkobj->kobj;
1756 	}
1757 	spin_unlock(&space_info->lock);
1758 
1759 	ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
1760 			  btrfs_bg_type_to_raid_name(rkobj->flags));
1761 	memalloc_nofs_restore(nofs_flag);
1762 	if (ret) {
1763 		spin_lock(&space_info->lock);
1764 		space_info->block_group_kobjs[index] = NULL;
1765 		spin_unlock(&space_info->lock);
1766 		kobject_put(&rkobj->kobj);
1767 		btrfs_warn(fs_info,
1768 			"failed to add kobject for block cache, ignoring");
1769 		return;
1770 	}
1771 }
1772 
1773 /*
1774  * Remove sysfs directories for all block group types of a given space info and
1775  * the space info as well
1776  */
1777 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
1778 {
1779 	int i;
1780 
1781 	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1782 		struct kobject *kobj;
1783 
1784 		kobj = space_info->block_group_kobjs[i];
1785 		space_info->block_group_kobjs[i] = NULL;
1786 		if (kobj) {
1787 			kobject_del(kobj);
1788 			kobject_put(kobj);
1789 		}
1790 	}
1791 	kobject_del(&space_info->kobj);
1792 	kobject_put(&space_info->kobj);
1793 }
1794 
1795 static const char *alloc_name(u64 flags)
1796 {
1797 	switch (flags) {
1798 	case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
1799 		return "mixed";
1800 	case BTRFS_BLOCK_GROUP_METADATA:
1801 		return "metadata";
1802 	case BTRFS_BLOCK_GROUP_DATA:
1803 		return "data";
1804 	case BTRFS_BLOCK_GROUP_SYSTEM:
1805 		return "system";
1806 	default:
1807 		WARN_ON(1);
1808 		return "invalid-combination";
1809 	}
1810 }
1811 
1812 /*
1813  * Create a sysfs entry for a space info type at path
1814  * /sys/fs/btrfs/UUID/allocation/TYPE
1815  */
1816 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
1817 				    struct btrfs_space_info *space_info)
1818 {
1819 	int ret;
1820 
1821 	ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
1822 				   fs_info->space_info_kobj, "%s",
1823 				   alloc_name(space_info->flags));
1824 	if (ret) {
1825 		kobject_put(&space_info->kobj);
1826 		return ret;
1827 	}
1828 
1829 	return 0;
1830 }
1831 
1832 void btrfs_sysfs_remove_device(struct btrfs_device *device)
1833 {
1834 	struct kobject *devices_kobj;
1835 
1836 	/*
1837 	 * Seed fs_devices devices_kobj aren't used, fetch kobject from the
1838 	 * fs_info::fs_devices.
1839 	 */
1840 	devices_kobj = device->fs_info->fs_devices->devices_kobj;
1841 	ASSERT(devices_kobj);
1842 
1843 	if (device->bdev)
1844 		sysfs_remove_link(devices_kobj, bdev_kobj(device->bdev)->name);
1845 
1846 	if (device->devid_kobj.state_initialized) {
1847 		kobject_del(&device->devid_kobj);
1848 		kobject_put(&device->devid_kobj);
1849 		wait_for_completion(&device->kobj_unregister);
1850 	}
1851 }
1852 
1853 static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj,
1854 					         struct kobj_attribute *a,
1855 					         char *buf)
1856 {
1857 	int val;
1858 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1859 						   devid_kobj);
1860 
1861 	val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
1862 
1863 	return sysfs_emit(buf, "%d\n", val);
1864 }
1865 BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show);
1866 
1867 static ssize_t btrfs_devinfo_missing_show(struct kobject *kobj,
1868 					struct kobj_attribute *a, char *buf)
1869 {
1870 	int val;
1871 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1872 						   devid_kobj);
1873 
1874 	val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
1875 
1876 	return sysfs_emit(buf, "%d\n", val);
1877 }
1878 BTRFS_ATTR(devid, missing, btrfs_devinfo_missing_show);
1879 
1880 static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj,
1881 					         struct kobj_attribute *a,
1882 					         char *buf)
1883 {
1884 	int val;
1885 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1886 						   devid_kobj);
1887 
1888 	val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
1889 
1890 	return sysfs_emit(buf, "%d\n", val);
1891 }
1892 BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show);
1893 
1894 static ssize_t btrfs_devinfo_scrub_speed_max_show(struct kobject *kobj,
1895 					     struct kobj_attribute *a,
1896 					     char *buf)
1897 {
1898 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1899 						   devid_kobj);
1900 
1901 	return sysfs_emit(buf, "%llu\n", READ_ONCE(device->scrub_speed_max));
1902 }
1903 
1904 static ssize_t btrfs_devinfo_scrub_speed_max_store(struct kobject *kobj,
1905 					      struct kobj_attribute *a,
1906 					      const char *buf, size_t len)
1907 {
1908 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1909 						   devid_kobj);
1910 	char *endptr;
1911 	unsigned long long limit;
1912 
1913 	limit = memparse(buf, &endptr);
1914 	/* There could be trailing '\n', also catch any typos after the value. */
1915 	endptr = skip_spaces(endptr);
1916 	if (*endptr != 0)
1917 		return -EINVAL;
1918 	WRITE_ONCE(device->scrub_speed_max, limit);
1919 	return len;
1920 }
1921 BTRFS_ATTR_RW(devid, scrub_speed_max, btrfs_devinfo_scrub_speed_max_show,
1922 	      btrfs_devinfo_scrub_speed_max_store);
1923 
1924 static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj,
1925 					    struct kobj_attribute *a, char *buf)
1926 {
1927 	int val;
1928 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1929 						   devid_kobj);
1930 
1931 	val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
1932 
1933 	return sysfs_emit(buf, "%d\n", val);
1934 }
1935 BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show);
1936 
1937 static ssize_t btrfs_devinfo_fsid_show(struct kobject *kobj,
1938 				       struct kobj_attribute *a, char *buf)
1939 {
1940 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1941 						   devid_kobj);
1942 
1943 	return sysfs_emit(buf, "%pU\n", device->fs_devices->fsid);
1944 }
1945 BTRFS_ATTR(devid, fsid, btrfs_devinfo_fsid_show);
1946 
1947 static ssize_t btrfs_devinfo_error_stats_show(struct kobject *kobj,
1948 		struct kobj_attribute *a, char *buf)
1949 {
1950 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1951 						   devid_kobj);
1952 
1953 	if (!device->dev_stats_valid)
1954 		return sysfs_emit(buf, "invalid\n");
1955 
1956 	/*
1957 	 * Print all at once so we get a snapshot of all values from the same
1958 	 * time. Keep them in sync and in order of definition of
1959 	 * btrfs_dev_stat_values.
1960 	 */
1961 	return sysfs_emit(buf,
1962 		"write_errs %d\n"
1963 		"read_errs %d\n"
1964 		"flush_errs %d\n"
1965 		"corruption_errs %d\n"
1966 		"generation_errs %d\n",
1967 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_WRITE_ERRS),
1968 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_READ_ERRS),
1969 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_FLUSH_ERRS),
1970 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_CORRUPTION_ERRS),
1971 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_GENERATION_ERRS));
1972 }
1973 BTRFS_ATTR(devid, error_stats, btrfs_devinfo_error_stats_show);
1974 
1975 /*
1976  * Information about one device.
1977  *
1978  * Path: /sys/fs/btrfs/<uuid>/devinfo/<devid>/
1979  */
1980 static struct attribute *devid_attrs[] = {
1981 	BTRFS_ATTR_PTR(devid, error_stats),
1982 	BTRFS_ATTR_PTR(devid, fsid),
1983 	BTRFS_ATTR_PTR(devid, in_fs_metadata),
1984 	BTRFS_ATTR_PTR(devid, missing),
1985 	BTRFS_ATTR_PTR(devid, replace_target),
1986 	BTRFS_ATTR_PTR(devid, scrub_speed_max),
1987 	BTRFS_ATTR_PTR(devid, writeable),
1988 	NULL
1989 };
1990 ATTRIBUTE_GROUPS(devid);
1991 
1992 static void btrfs_release_devid_kobj(struct kobject *kobj)
1993 {
1994 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1995 						   devid_kobj);
1996 
1997 	memset(&device->devid_kobj, 0, sizeof(struct kobject));
1998 	complete(&device->kobj_unregister);
1999 }
2000 
2001 static const struct kobj_type devid_ktype = {
2002 	.sysfs_ops	= &kobj_sysfs_ops,
2003 	.default_groups = devid_groups,
2004 	.release	= btrfs_release_devid_kobj,
2005 };
2006 
2007 int btrfs_sysfs_add_device(struct btrfs_device *device)
2008 {
2009 	int ret;
2010 	unsigned int nofs_flag;
2011 	struct kobject *devices_kobj;
2012 	struct kobject *devinfo_kobj;
2013 
2014 	/*
2015 	 * Make sure we use the fs_info::fs_devices to fetch the kobjects even
2016 	 * for the seed fs_devices
2017 	 */
2018 	devices_kobj = device->fs_info->fs_devices->devices_kobj;
2019 	devinfo_kobj = device->fs_info->fs_devices->devinfo_kobj;
2020 	ASSERT(devices_kobj);
2021 	ASSERT(devinfo_kobj);
2022 
2023 	nofs_flag = memalloc_nofs_save();
2024 
2025 	if (device->bdev) {
2026 		struct kobject *disk_kobj = bdev_kobj(device->bdev);
2027 
2028 		ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
2029 		if (ret) {
2030 			btrfs_warn(device->fs_info,
2031 				"creating sysfs device link for devid %llu failed: %d",
2032 				device->devid, ret);
2033 			goto out;
2034 		}
2035 	}
2036 
2037 	init_completion(&device->kobj_unregister);
2038 	ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype,
2039 				   devinfo_kobj, "%llu", device->devid);
2040 	if (ret) {
2041 		kobject_put(&device->devid_kobj);
2042 		btrfs_warn(device->fs_info,
2043 			   "devinfo init for devid %llu failed: %d",
2044 			   device->devid, ret);
2045 	}
2046 
2047 out:
2048 	memalloc_nofs_restore(nofs_flag);
2049 	return ret;
2050 }
2051 
2052 static int btrfs_sysfs_add_fs_devices(struct btrfs_fs_devices *fs_devices)
2053 {
2054 	int ret;
2055 	struct btrfs_device *device;
2056 	struct btrfs_fs_devices *seed;
2057 
2058 	list_for_each_entry(device, &fs_devices->devices, dev_list) {
2059 		ret = btrfs_sysfs_add_device(device);
2060 		if (ret)
2061 			goto fail;
2062 	}
2063 
2064 	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
2065 		list_for_each_entry(device, &seed->devices, dev_list) {
2066 			ret = btrfs_sysfs_add_device(device);
2067 			if (ret)
2068 				goto fail;
2069 		}
2070 	}
2071 
2072 	return 0;
2073 
2074 fail:
2075 	btrfs_sysfs_remove_fs_devices(fs_devices);
2076 	return ret;
2077 }
2078 
2079 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
2080 {
2081 	int ret;
2082 
2083 	ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
2084 	if (ret)
2085 		pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
2086 			action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
2087 			&disk_to_dev(bdev->bd_disk)->kobj);
2088 }
2089 
2090 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices)
2091 
2092 {
2093 	char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2094 
2095 	/*
2096 	 * Sprouting changes fsid of the mounted filesystem, rename the fsid
2097 	 * directory
2098 	 */
2099 	snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fs_devices->fsid);
2100 	if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
2101 		btrfs_warn(fs_devices->fs_info,
2102 				"sysfs: failed to create fsid for sprout");
2103 }
2104 
2105 void btrfs_sysfs_update_devid(struct btrfs_device *device)
2106 {
2107 	char tmp[24];
2108 
2109 	snprintf(tmp, sizeof(tmp), "%llu", device->devid);
2110 
2111 	if (kobject_rename(&device->devid_kobj, tmp))
2112 		btrfs_warn(device->fs_devices->fs_info,
2113 			   "sysfs: failed to update devid for %llu",
2114 			   device->devid);
2115 }
2116 
2117 /* /sys/fs/btrfs/ entry */
2118 static struct kset *btrfs_kset;
2119 
2120 /*
2121  * Creates:
2122  *		/sys/fs/btrfs/UUID
2123  *
2124  * Can be called by the device discovery thread.
2125  */
2126 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
2127 {
2128 	int error;
2129 
2130 	init_completion(&fs_devs->kobj_unregister);
2131 	fs_devs->fsid_kobj.kset = btrfs_kset;
2132 	error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
2133 				     "%pU", fs_devs->fsid);
2134 	if (error) {
2135 		kobject_put(&fs_devs->fsid_kobj);
2136 		return error;
2137 	}
2138 
2139 	fs_devs->devices_kobj = kobject_create_and_add("devices",
2140 						       &fs_devs->fsid_kobj);
2141 	if (!fs_devs->devices_kobj) {
2142 		btrfs_err(fs_devs->fs_info,
2143 			  "failed to init sysfs device interface");
2144 		btrfs_sysfs_remove_fsid(fs_devs);
2145 		return -ENOMEM;
2146 	}
2147 
2148 	fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
2149 						       &fs_devs->fsid_kobj);
2150 	if (!fs_devs->devinfo_kobj) {
2151 		btrfs_err(fs_devs->fs_info,
2152 			  "failed to init sysfs devinfo kobject");
2153 		btrfs_sysfs_remove_fsid(fs_devs);
2154 		return -ENOMEM;
2155 	}
2156 
2157 	return 0;
2158 }
2159 
2160 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
2161 {
2162 	int error;
2163 	struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
2164 	struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
2165 
2166 	error = btrfs_sysfs_add_fs_devices(fs_devs);
2167 	if (error)
2168 		return error;
2169 
2170 	error = sysfs_create_files(fsid_kobj, btrfs_attrs);
2171 	if (error) {
2172 		btrfs_sysfs_remove_fs_devices(fs_devs);
2173 		return error;
2174 	}
2175 
2176 	error = sysfs_create_group(fsid_kobj,
2177 				   &btrfs_feature_attr_group);
2178 	if (error)
2179 		goto failure;
2180 
2181 #ifdef CONFIG_BTRFS_DEBUG
2182 	fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
2183 	if (!fs_info->debug_kobj) {
2184 		error = -ENOMEM;
2185 		goto failure;
2186 	}
2187 
2188 	error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
2189 	if (error)
2190 		goto failure;
2191 #endif
2192 
2193 	/* Discard directory */
2194 	fs_info->discard_kobj = kobject_create_and_add("discard", fsid_kobj);
2195 	if (!fs_info->discard_kobj) {
2196 		error = -ENOMEM;
2197 		goto failure;
2198 	}
2199 
2200 	error = sysfs_create_files(fs_info->discard_kobj, discard_attrs);
2201 	if (error)
2202 		goto failure;
2203 
2204 	error = addrm_unknown_feature_attrs(fs_info, true);
2205 	if (error)
2206 		goto failure;
2207 
2208 	error = sysfs_create_link(fsid_kobj, &fs_info->sb->s_bdi->dev->kobj, "bdi");
2209 	if (error)
2210 		goto failure;
2211 
2212 	fs_info->space_info_kobj = kobject_create_and_add("allocation",
2213 						  fsid_kobj);
2214 	if (!fs_info->space_info_kobj) {
2215 		error = -ENOMEM;
2216 		goto failure;
2217 	}
2218 
2219 	error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
2220 	if (error)
2221 		goto failure;
2222 
2223 	return 0;
2224 failure:
2225 	btrfs_sysfs_remove_mounted(fs_info);
2226 	return error;
2227 }
2228 
2229 static ssize_t qgroup_enabled_show(struct kobject *qgroups_kobj,
2230 				   struct kobj_attribute *a,
2231 				   char *buf)
2232 {
2233 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2234 	bool enabled;
2235 
2236 	spin_lock(&fs_info->qgroup_lock);
2237 	enabled = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON;
2238 	spin_unlock(&fs_info->qgroup_lock);
2239 
2240 	return sysfs_emit(buf, "%d\n", enabled);
2241 }
2242 BTRFS_ATTR(qgroups, enabled, qgroup_enabled_show);
2243 
2244 static ssize_t qgroup_mode_show(struct kobject *qgroups_kobj,
2245 				struct kobj_attribute *a,
2246 				char *buf)
2247 {
2248 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2249 	ssize_t ret = 0;
2250 
2251 	spin_lock(&fs_info->qgroup_lock);
2252 	ASSERT(btrfs_qgroup_enabled(fs_info));
2253 	switch (btrfs_qgroup_mode(fs_info)) {
2254 	case BTRFS_QGROUP_MODE_FULL:
2255 		ret = sysfs_emit(buf, "qgroup\n");
2256 		break;
2257 	case BTRFS_QGROUP_MODE_SIMPLE:
2258 		ret = sysfs_emit(buf, "squota\n");
2259 		break;
2260 	default:
2261 		btrfs_warn(fs_info, "unexpected qgroup mode %d\n",
2262 			   btrfs_qgroup_mode(fs_info));
2263 		break;
2264 	}
2265 	spin_unlock(&fs_info->qgroup_lock);
2266 
2267 	return ret;
2268 }
2269 BTRFS_ATTR(qgroups, mode, qgroup_mode_show);
2270 
2271 static ssize_t qgroup_inconsistent_show(struct kobject *qgroups_kobj,
2272 					struct kobj_attribute *a,
2273 					char *buf)
2274 {
2275 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2276 	bool inconsistent;
2277 
2278 	spin_lock(&fs_info->qgroup_lock);
2279 	inconsistent = (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT);
2280 	spin_unlock(&fs_info->qgroup_lock);
2281 
2282 	return sysfs_emit(buf, "%d\n", inconsistent);
2283 }
2284 BTRFS_ATTR(qgroups, inconsistent, qgroup_inconsistent_show);
2285 
2286 static ssize_t qgroup_drop_subtree_thres_show(struct kobject *qgroups_kobj,
2287 					      struct kobj_attribute *a,
2288 					      char *buf)
2289 {
2290 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2291 	u8 result;
2292 
2293 	spin_lock(&fs_info->qgroup_lock);
2294 	result = fs_info->qgroup_drop_subtree_thres;
2295 	spin_unlock(&fs_info->qgroup_lock);
2296 
2297 	return sysfs_emit(buf, "%d\n", result);
2298 }
2299 
2300 static ssize_t qgroup_drop_subtree_thres_store(struct kobject *qgroups_kobj,
2301 					       struct kobj_attribute *a,
2302 					       const char *buf, size_t len)
2303 {
2304 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2305 	u8 new_thres;
2306 	int ret;
2307 
2308 	ret = kstrtou8(buf, 10, &new_thres);
2309 	if (ret)
2310 		return -EINVAL;
2311 
2312 	if (new_thres > BTRFS_MAX_LEVEL)
2313 		return -EINVAL;
2314 
2315 	spin_lock(&fs_info->qgroup_lock);
2316 	fs_info->qgroup_drop_subtree_thres = new_thres;
2317 	spin_unlock(&fs_info->qgroup_lock);
2318 
2319 	return len;
2320 }
2321 BTRFS_ATTR_RW(qgroups, drop_subtree_threshold, qgroup_drop_subtree_thres_show,
2322 	      qgroup_drop_subtree_thres_store);
2323 
2324 /*
2325  * Qgroups global info
2326  *
2327  * Path: /sys/fs/btrfs/<uuid>/qgroups/
2328  */
2329 static struct attribute *qgroups_attrs[] = {
2330 	BTRFS_ATTR_PTR(qgroups, enabled),
2331 	BTRFS_ATTR_PTR(qgroups, inconsistent),
2332 	BTRFS_ATTR_PTR(qgroups, drop_subtree_threshold),
2333 	BTRFS_ATTR_PTR(qgroups, mode),
2334 	NULL
2335 };
2336 ATTRIBUTE_GROUPS(qgroups);
2337 
2338 static void qgroups_release(struct kobject *kobj)
2339 {
2340 	kfree(kobj);
2341 }
2342 
2343 static const struct kobj_type qgroups_ktype = {
2344 	.sysfs_ops = &kobj_sysfs_ops,
2345 	.default_groups = qgroups_groups,
2346 	.release = qgroups_release,
2347 };
2348 
2349 static inline struct btrfs_fs_info *qgroup_kobj_to_fs_info(struct kobject *kobj)
2350 {
2351 	return to_fs_info(kobj->parent->parent);
2352 }
2353 
2354 #define QGROUP_ATTR(_member, _show_name)					\
2355 static ssize_t btrfs_qgroup_show_##_member(struct kobject *qgroup_kobj,		\
2356 					   struct kobj_attribute *a,		\
2357 					   char *buf)				\
2358 {										\
2359 	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2360 	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2361 			struct btrfs_qgroup, kobj);				\
2362 	return btrfs_show_u64(&qgroup->_member, &fs_info->qgroup_lock, buf);	\
2363 }										\
2364 BTRFS_ATTR(qgroup, _show_name, btrfs_qgroup_show_##_member)
2365 
2366 #define QGROUP_RSV_ATTR(_name, _type)						\
2367 static ssize_t btrfs_qgroup_rsv_show_##_name(struct kobject *qgroup_kobj,	\
2368 					     struct kobj_attribute *a,		\
2369 					     char *buf)				\
2370 {										\
2371 	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2372 	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2373 			struct btrfs_qgroup, kobj);				\
2374 	return btrfs_show_u64(&qgroup->rsv.values[_type],			\
2375 			&fs_info->qgroup_lock, buf);				\
2376 }										\
2377 BTRFS_ATTR(qgroup, rsv_##_name, btrfs_qgroup_rsv_show_##_name)
2378 
2379 QGROUP_ATTR(rfer, referenced);
2380 QGROUP_ATTR(excl, exclusive);
2381 QGROUP_ATTR(max_rfer, max_referenced);
2382 QGROUP_ATTR(max_excl, max_exclusive);
2383 QGROUP_ATTR(lim_flags, limit_flags);
2384 QGROUP_RSV_ATTR(data, BTRFS_QGROUP_RSV_DATA);
2385 QGROUP_RSV_ATTR(meta_pertrans, BTRFS_QGROUP_RSV_META_PERTRANS);
2386 QGROUP_RSV_ATTR(meta_prealloc, BTRFS_QGROUP_RSV_META_PREALLOC);
2387 
2388 /*
2389  * Qgroup information.
2390  *
2391  * Path: /sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>/
2392  */
2393 static struct attribute *qgroup_attrs[] = {
2394 	BTRFS_ATTR_PTR(qgroup, referenced),
2395 	BTRFS_ATTR_PTR(qgroup, exclusive),
2396 	BTRFS_ATTR_PTR(qgroup, max_referenced),
2397 	BTRFS_ATTR_PTR(qgroup, max_exclusive),
2398 	BTRFS_ATTR_PTR(qgroup, limit_flags),
2399 	BTRFS_ATTR_PTR(qgroup, rsv_data),
2400 	BTRFS_ATTR_PTR(qgroup, rsv_meta_pertrans),
2401 	BTRFS_ATTR_PTR(qgroup, rsv_meta_prealloc),
2402 	NULL
2403 };
2404 ATTRIBUTE_GROUPS(qgroup);
2405 
2406 static void qgroup_release(struct kobject *kobj)
2407 {
2408 	struct btrfs_qgroup *qgroup = container_of(kobj, struct btrfs_qgroup, kobj);
2409 
2410 	memset(&qgroup->kobj, 0, sizeof(*kobj));
2411 }
2412 
2413 static const struct kobj_type qgroup_ktype = {
2414 	.sysfs_ops = &kobj_sysfs_ops,
2415 	.release = qgroup_release,
2416 	.default_groups = qgroup_groups,
2417 };
2418 
2419 int btrfs_sysfs_add_one_qgroup(struct btrfs_fs_info *fs_info,
2420 				struct btrfs_qgroup *qgroup)
2421 {
2422 	struct kobject *qgroups_kobj = fs_info->qgroups_kobj;
2423 	int ret;
2424 
2425 	if (btrfs_is_testing(fs_info))
2426 		return 0;
2427 	if (qgroup->kobj.state_initialized)
2428 		return 0;
2429 	if (!qgroups_kobj)
2430 		return -EINVAL;
2431 
2432 	ret = kobject_init_and_add(&qgroup->kobj, &qgroup_ktype, qgroups_kobj,
2433 			"%hu_%llu", btrfs_qgroup_level(qgroup->qgroupid),
2434 			btrfs_qgroup_subvolid(qgroup->qgroupid));
2435 	if (ret < 0)
2436 		kobject_put(&qgroup->kobj);
2437 
2438 	return ret;
2439 }
2440 
2441 void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info)
2442 {
2443 	struct btrfs_qgroup *qgroup;
2444 	struct btrfs_qgroup *next;
2445 
2446 	if (btrfs_is_testing(fs_info))
2447 		return;
2448 
2449 	rbtree_postorder_for_each_entry_safe(qgroup, next,
2450 					     &fs_info->qgroup_tree, node)
2451 		btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
2452 	if (fs_info->qgroups_kobj) {
2453 		kobject_del(fs_info->qgroups_kobj);
2454 		kobject_put(fs_info->qgroups_kobj);
2455 		fs_info->qgroups_kobj = NULL;
2456 	}
2457 }
2458 
2459 /* Called when qgroups get initialized, thus there is no need for locking */
2460 int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info)
2461 {
2462 	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2463 	struct btrfs_qgroup *qgroup;
2464 	struct btrfs_qgroup *next;
2465 	int ret = 0;
2466 
2467 	if (btrfs_is_testing(fs_info))
2468 		return 0;
2469 
2470 	ASSERT(fsid_kobj);
2471 	if (fs_info->qgroups_kobj)
2472 		return 0;
2473 
2474 	fs_info->qgroups_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
2475 	if (!fs_info->qgroups_kobj)
2476 		return -ENOMEM;
2477 
2478 	ret = kobject_init_and_add(fs_info->qgroups_kobj, &qgroups_ktype,
2479 				   fsid_kobj, "qgroups");
2480 	if (ret < 0)
2481 		goto out;
2482 
2483 	rbtree_postorder_for_each_entry_safe(qgroup, next,
2484 					     &fs_info->qgroup_tree, node) {
2485 		ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
2486 		if (ret < 0)
2487 			goto out;
2488 	}
2489 
2490 out:
2491 	if (ret < 0)
2492 		btrfs_sysfs_del_qgroups(fs_info);
2493 	return ret;
2494 }
2495 
2496 void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
2497 				struct btrfs_qgroup *qgroup)
2498 {
2499 	if (btrfs_is_testing(fs_info))
2500 		return;
2501 
2502 	if (qgroup->kobj.state_initialized) {
2503 		kobject_del(&qgroup->kobj);
2504 		kobject_put(&qgroup->kobj);
2505 	}
2506 }
2507 
2508 /*
2509  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
2510  * values in superblock. Call after any changes to incompat/compat_ro flags
2511  */
2512 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info)
2513 {
2514 	struct kobject *fsid_kobj;
2515 	int ret;
2516 
2517 	if (!fs_info)
2518 		return;
2519 
2520 	fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2521 	if (!fsid_kobj->state_initialized)
2522 		return;
2523 
2524 	ret = sysfs_update_group(fsid_kobj, &btrfs_feature_attr_group);
2525 	if (ret < 0)
2526 		btrfs_warn(fs_info,
2527 			   "failed to update /sys/fs/btrfs/%pU/features: %d",
2528 			   fs_info->fs_devices->fsid, ret);
2529 }
2530 
2531 int __init btrfs_init_sysfs(void)
2532 {
2533 	int ret;
2534 
2535 	btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
2536 	if (!btrfs_kset)
2537 		return -ENOMEM;
2538 
2539 	init_feature_attrs();
2540 	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2541 	if (ret)
2542 		goto out2;
2543 	ret = sysfs_merge_group(&btrfs_kset->kobj,
2544 				&btrfs_static_feature_attr_group);
2545 	if (ret)
2546 		goto out_remove_group;
2547 
2548 #ifdef CONFIG_BTRFS_DEBUG
2549 	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2550 	if (ret) {
2551 		sysfs_unmerge_group(&btrfs_kset->kobj,
2552 				    &btrfs_static_feature_attr_group);
2553 		goto out_remove_group;
2554 	}
2555 #endif
2556 
2557 	return 0;
2558 
2559 out_remove_group:
2560 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2561 out2:
2562 	kset_unregister(btrfs_kset);
2563 
2564 	return ret;
2565 }
2566 
2567 void __cold btrfs_exit_sysfs(void)
2568 {
2569 	sysfs_unmerge_group(&btrfs_kset->kobj,
2570 			    &btrfs_static_feature_attr_group);
2571 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2572 #ifdef CONFIG_BTRFS_DEBUG
2573 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2574 #endif
2575 	kset_unregister(btrfs_kset);
2576 }
2577