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_EXPERIMENTAL
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_EXPERIMENTAL
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 	if (BTRFS_MIN_BLOCKSIZE != SZ_4K && BTRFS_MIN_BLOCKSIZE != PAGE_SIZE)
415 		ret += sysfs_emit_at(buf, ret, "%u ", BTRFS_MIN_BLOCKSIZE);
416 	if (PAGE_SIZE > SZ_4K)
417 		ret += sysfs_emit_at(buf, ret, "%u ", SZ_4K);
418 	ret += sysfs_emit_at(buf, ret, "%lu\n", PAGE_SIZE);
419 
420 	return ret;
421 }
422 BTRFS_ATTR(static_feature, supported_sectorsizes,
423 	   supported_sectorsizes_show);
424 
425 static ssize_t acl_show(struct kobject *kobj, struct kobj_attribute *a, char *buf)
426 {
427 	return sysfs_emit(buf, "%d\n", IS_ENABLED(CONFIG_BTRFS_FS_POSIX_ACL));
428 }
429 BTRFS_ATTR(static_feature, acl, acl_show);
430 
431 static ssize_t temp_fsid_supported_show(struct kobject *kobj,
432 					struct kobj_attribute *a, char *buf)
433 {
434 	return sysfs_emit(buf, "0\n");
435 }
436 BTRFS_ATTR(static_feature, temp_fsid, temp_fsid_supported_show);
437 
438 /*
439  * Features which only depend on kernel version.
440  *
441  * These are listed in /sys/fs/btrfs/features along with
442  * btrfs_supported_feature_attrs.
443  */
444 static struct attribute *btrfs_supported_static_feature_attrs[] = {
445 	BTRFS_ATTR_PTR(static_feature, acl),
446 	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
447 	BTRFS_ATTR_PTR(static_feature, supported_checksums),
448 	BTRFS_ATTR_PTR(static_feature, send_stream_version),
449 	BTRFS_ATTR_PTR(static_feature, supported_rescue_options),
450 	BTRFS_ATTR_PTR(static_feature, supported_sectorsizes),
451 	BTRFS_ATTR_PTR(static_feature, temp_fsid),
452 	NULL
453 };
454 
455 static const struct attribute_group btrfs_static_feature_attr_group = {
456 	.name = "features",
457 	.attrs = btrfs_supported_static_feature_attrs,
458 };
459 
460 /*
461  * Discard statistics and tunables
462  */
463 #define discard_to_fs_info(_kobj)	to_fs_info(get_btrfs_kobj(_kobj))
464 
465 static ssize_t btrfs_discardable_bytes_show(struct kobject *kobj,
466 					    struct kobj_attribute *a,
467 					    char *buf)
468 {
469 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
470 
471 	return sysfs_emit(buf, "%lld\n",
472 			atomic64_read(&fs_info->discard_ctl.discardable_bytes));
473 }
474 BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
475 
476 static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
477 					      struct kobj_attribute *a,
478 					      char *buf)
479 {
480 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
481 
482 	return sysfs_emit(buf, "%d\n",
483 			atomic_read(&fs_info->discard_ctl.discardable_extents));
484 }
485 BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
486 
487 static ssize_t btrfs_discard_bitmap_bytes_show(struct kobject *kobj,
488 					       struct kobj_attribute *a,
489 					       char *buf)
490 {
491 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
492 
493 	return sysfs_emit(buf, "%llu\n",
494 			  fs_info->discard_ctl.discard_bitmap_bytes);
495 }
496 BTRFS_ATTR(discard, discard_bitmap_bytes, btrfs_discard_bitmap_bytes_show);
497 
498 static ssize_t btrfs_discard_bytes_saved_show(struct kobject *kobj,
499 					      struct kobj_attribute *a,
500 					      char *buf)
501 {
502 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
503 
504 	return sysfs_emit(buf, "%lld\n",
505 		atomic64_read(&fs_info->discard_ctl.discard_bytes_saved));
506 }
507 BTRFS_ATTR(discard, discard_bytes_saved, btrfs_discard_bytes_saved_show);
508 
509 static ssize_t btrfs_discard_extent_bytes_show(struct kobject *kobj,
510 					       struct kobj_attribute *a,
511 					       char *buf)
512 {
513 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
514 
515 	return sysfs_emit(buf, "%llu\n",
516 			  fs_info->discard_ctl.discard_extent_bytes);
517 }
518 BTRFS_ATTR(discard, discard_extent_bytes, btrfs_discard_extent_bytes_show);
519 
520 static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
521 					     struct kobj_attribute *a,
522 					     char *buf)
523 {
524 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
525 
526 	return sysfs_emit(buf, "%u\n",
527 			  READ_ONCE(fs_info->discard_ctl.iops_limit));
528 }
529 
530 static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
531 					      struct kobj_attribute *a,
532 					      const char *buf, size_t len)
533 {
534 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
535 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
536 	u32 iops_limit;
537 	int ret;
538 
539 	ret = kstrtou32(buf, 10, &iops_limit);
540 	if (ret)
541 		return -EINVAL;
542 
543 	WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
544 	btrfs_discard_calc_delay(discard_ctl);
545 	btrfs_discard_schedule_work(discard_ctl, true);
546 	return len;
547 }
548 BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
549 	      btrfs_discard_iops_limit_store);
550 
551 static ssize_t btrfs_discard_kbps_limit_show(struct kobject *kobj,
552 					     struct kobj_attribute *a,
553 					     char *buf)
554 {
555 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
556 
557 	return sysfs_emit(buf, "%u\n",
558 			  READ_ONCE(fs_info->discard_ctl.kbps_limit));
559 }
560 
561 static ssize_t btrfs_discard_kbps_limit_store(struct kobject *kobj,
562 					      struct kobj_attribute *a,
563 					      const char *buf, size_t len)
564 {
565 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
566 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
567 	u32 kbps_limit;
568 	int ret;
569 
570 	ret = kstrtou32(buf, 10, &kbps_limit);
571 	if (ret)
572 		return -EINVAL;
573 
574 	WRITE_ONCE(discard_ctl->kbps_limit, kbps_limit);
575 	btrfs_discard_schedule_work(discard_ctl, true);
576 	return len;
577 }
578 BTRFS_ATTR_RW(discard, kbps_limit, btrfs_discard_kbps_limit_show,
579 	      btrfs_discard_kbps_limit_store);
580 
581 static ssize_t btrfs_discard_max_discard_size_show(struct kobject *kobj,
582 						   struct kobj_attribute *a,
583 						   char *buf)
584 {
585 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
586 
587 	return sysfs_emit(buf, "%llu\n",
588 			  READ_ONCE(fs_info->discard_ctl.max_discard_size));
589 }
590 
591 static ssize_t btrfs_discard_max_discard_size_store(struct kobject *kobj,
592 						    struct kobj_attribute *a,
593 						    const char *buf, size_t len)
594 {
595 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
596 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
597 	u64 max_discard_size;
598 	int ret;
599 
600 	ret = kstrtou64(buf, 10, &max_discard_size);
601 	if (ret)
602 		return -EINVAL;
603 
604 	WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);
605 
606 	return len;
607 }
608 BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
609 	      btrfs_discard_max_discard_size_store);
610 
611 /*
612  * Per-filesystem stats for discard (when mounted with discard=async).
613  *
614  * Path: /sys/fs/btrfs/<uuid>/discard/
615  */
616 static const struct attribute *discard_attrs[] = {
617 	BTRFS_ATTR_PTR(discard, discardable_bytes),
618 	BTRFS_ATTR_PTR(discard, discardable_extents),
619 	BTRFS_ATTR_PTR(discard, discard_bitmap_bytes),
620 	BTRFS_ATTR_PTR(discard, discard_bytes_saved),
621 	BTRFS_ATTR_PTR(discard, discard_extent_bytes),
622 	BTRFS_ATTR_PTR(discard, iops_limit),
623 	BTRFS_ATTR_PTR(discard, kbps_limit),
624 	BTRFS_ATTR_PTR(discard, max_discard_size),
625 	NULL,
626 };
627 
628 #ifdef CONFIG_BTRFS_DEBUG
629 
630 /*
631  * Per-filesystem runtime debugging exported via sysfs.
632  *
633  * Path: /sys/fs/btrfs/UUID/debug/
634  */
635 static const struct attribute *btrfs_debug_mount_attrs[] = {
636 	NULL,
637 };
638 
639 /*
640  * Runtime debugging exported via sysfs, applies to all mounted filesystems.
641  *
642  * Path: /sys/fs/btrfs/debug
643  */
644 static struct attribute *btrfs_debug_feature_attrs[] = {
645 	NULL
646 };
647 
648 static const struct attribute_group btrfs_debug_feature_attr_group = {
649 	.name = "debug",
650 	.attrs = btrfs_debug_feature_attrs,
651 };
652 
653 #endif
654 
655 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
656 {
657 	u64 val;
658 	if (lock)
659 		spin_lock(lock);
660 	val = *value_ptr;
661 	if (lock)
662 		spin_unlock(lock);
663 	return sysfs_emit(buf, "%llu\n", val);
664 }
665 
666 static ssize_t global_rsv_size_show(struct kobject *kobj,
667 				    struct kobj_attribute *ka, char *buf)
668 {
669 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
670 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
671 	return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
672 }
673 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
674 
675 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
676 					struct kobj_attribute *a, char *buf)
677 {
678 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
679 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
680 	return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
681 }
682 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
683 
684 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
685 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
686 
687 static ssize_t raid_bytes_show(struct kobject *kobj,
688 			       struct kobj_attribute *attr, char *buf);
689 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
690 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
691 
692 static ssize_t raid_bytes_show(struct kobject *kobj,
693 			       struct kobj_attribute *attr, char *buf)
694 
695 {
696 	struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
697 	struct btrfs_block_group *block_group;
698 	int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
699 	u64 val = 0;
700 
701 	down_read(&sinfo->groups_sem);
702 	list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
703 		if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
704 			val += block_group->length;
705 		else
706 			val += block_group->used;
707 	}
708 	up_read(&sinfo->groups_sem);
709 	return sysfs_emit(buf, "%llu\n", val);
710 }
711 
712 /*
713  * Allocation information about block group profiles.
714  *
715  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>/
716  */
717 static struct attribute *raid_attrs[] = {
718 	BTRFS_ATTR_PTR(raid, total_bytes),
719 	BTRFS_ATTR_PTR(raid, used_bytes),
720 	NULL
721 };
722 ATTRIBUTE_GROUPS(raid);
723 
724 static void release_raid_kobj(struct kobject *kobj)
725 {
726 	kfree(to_raid_kobj(kobj));
727 }
728 
729 static const struct kobj_type btrfs_raid_ktype = {
730 	.sysfs_ops = &kobj_sysfs_ops,
731 	.release = release_raid_kobj,
732 	.default_groups = raid_groups,
733 };
734 
735 #define SPACE_INFO_ATTR(field)						\
736 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,	\
737 					     struct kobj_attribute *a,	\
738 					     char *buf)			\
739 {									\
740 	struct btrfs_space_info *sinfo = to_space_info(kobj);		\
741 	return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);	\
742 }									\
743 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
744 
745 static ssize_t btrfs_chunk_size_show(struct kobject *kobj,
746 				     struct kobj_attribute *a, char *buf)
747 {
748 	struct btrfs_space_info *sinfo = to_space_info(kobj);
749 
750 	return sysfs_emit(buf, "%llu\n", READ_ONCE(sinfo->chunk_size));
751 }
752 
753 /*
754  * Store new chunk size in space info. Can be called on a read-only filesystem.
755  *
756  * If the new chunk size value is larger than 10% of free space it is reduced
757  * to match that limit. Alignment must be to 256M and the system chunk size
758  * cannot be set.
759  */
760 static ssize_t btrfs_chunk_size_store(struct kobject *kobj,
761 				      struct kobj_attribute *a,
762 				      const char *buf, size_t len)
763 {
764 	struct btrfs_space_info *space_info = to_space_info(kobj);
765 	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
766 	char *retptr;
767 	u64 val;
768 
769 	if (!capable(CAP_SYS_ADMIN))
770 		return -EPERM;
771 
772 	if (!fs_info->fs_devices)
773 		return -EINVAL;
774 
775 	if (btrfs_is_zoned(fs_info))
776 		return -EINVAL;
777 
778 	/* System block type must not be changed. */
779 	if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
780 		return -EPERM;
781 
782 	val = memparse(buf, &retptr);
783 	/* There could be trailing '\n', also catch any typos after the value */
784 	retptr = skip_spaces(retptr);
785 	if (*retptr != 0 || val == 0)
786 		return -EINVAL;
787 
788 	val = min(val, BTRFS_MAX_DATA_CHUNK_SIZE);
789 
790 	/* Limit stripe size to 10% of available space. */
791 	val = min(mult_perc(fs_info->fs_devices->total_rw_bytes, 10), val);
792 
793 	/* Must be multiple of 256M. */
794 	val &= ~((u64)SZ_256M - 1);
795 
796 	/* Must be at least 256M. */
797 	if (val < SZ_256M)
798 		return -EINVAL;
799 
800 	btrfs_update_space_info_chunk_size(space_info, val);
801 
802 	return len;
803 }
804 
805 static ssize_t btrfs_size_classes_show(struct kobject *kobj,
806 				       struct kobj_attribute *a, char *buf)
807 {
808 	struct btrfs_space_info *sinfo = to_space_info(kobj);
809 	struct btrfs_block_group *bg;
810 	u32 none = 0;
811 	u32 small = 0;
812 	u32 medium = 0;
813 	u32 large = 0;
814 
815 	for (int i = 0; i < BTRFS_NR_RAID_TYPES; ++i) {
816 		down_read(&sinfo->groups_sem);
817 		list_for_each_entry(bg, &sinfo->block_groups[i], list) {
818 			if (!btrfs_block_group_should_use_size_class(bg))
819 				continue;
820 			switch (bg->size_class) {
821 			case BTRFS_BG_SZ_NONE:
822 				none++;
823 				break;
824 			case BTRFS_BG_SZ_SMALL:
825 				small++;
826 				break;
827 			case BTRFS_BG_SZ_MEDIUM:
828 				medium++;
829 				break;
830 			case BTRFS_BG_SZ_LARGE:
831 				large++;
832 				break;
833 			}
834 		}
835 		up_read(&sinfo->groups_sem);
836 	}
837 	return sysfs_emit(buf, "none %u\n"
838 			       "small %u\n"
839 			       "medium %u\n"
840 			       "large %u\n",
841 			       none, small, medium, large);
842 }
843 
844 #ifdef CONFIG_BTRFS_DEBUG
845 /*
846  * Request chunk allocation with current chunk size.
847  */
848 static ssize_t btrfs_force_chunk_alloc_store(struct kobject *kobj,
849 					     struct kobj_attribute *a,
850 					     const char *buf, size_t len)
851 {
852 	struct btrfs_space_info *space_info = to_space_info(kobj);
853 	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
854 	struct btrfs_trans_handle *trans;
855 	bool val;
856 	int ret;
857 
858 	if (!capable(CAP_SYS_ADMIN))
859 		return -EPERM;
860 
861 	if (sb_rdonly(fs_info->sb))
862 		return -EROFS;
863 
864 	ret = kstrtobool(buf, &val);
865 	if (ret)
866 		return ret;
867 
868 	if (!val)
869 		return -EINVAL;
870 
871 	/*
872 	 * This is unsafe to be called from sysfs context and may cause
873 	 * unexpected problems.
874 	 */
875 	trans = btrfs_start_transaction(fs_info->tree_root, 0);
876 	if (IS_ERR(trans))
877 		return PTR_ERR(trans);
878 	ret = btrfs_force_chunk_alloc(trans, space_info->flags);
879 	btrfs_end_transaction(trans);
880 
881 	if (ret == 1)
882 		return len;
883 
884 	return -ENOSPC;
885 }
886 BTRFS_ATTR_W(space_info, force_chunk_alloc, btrfs_force_chunk_alloc_store);
887 
888 #endif
889 
890 SPACE_INFO_ATTR(flags);
891 SPACE_INFO_ATTR(total_bytes);
892 SPACE_INFO_ATTR(bytes_used);
893 SPACE_INFO_ATTR(bytes_pinned);
894 SPACE_INFO_ATTR(bytes_reserved);
895 SPACE_INFO_ATTR(bytes_may_use);
896 SPACE_INFO_ATTR(bytes_readonly);
897 SPACE_INFO_ATTR(bytes_zone_unusable);
898 SPACE_INFO_ATTR(disk_used);
899 SPACE_INFO_ATTR(disk_total);
900 SPACE_INFO_ATTR(reclaim_count);
901 SPACE_INFO_ATTR(reclaim_bytes);
902 SPACE_INFO_ATTR(reclaim_errors);
903 BTRFS_ATTR_RW(space_info, chunk_size, btrfs_chunk_size_show, btrfs_chunk_size_store);
904 BTRFS_ATTR(space_info, size_classes, btrfs_size_classes_show);
905 
906 static ssize_t btrfs_sinfo_bg_reclaim_threshold_show(struct kobject *kobj,
907 						     struct kobj_attribute *a,
908 						     char *buf)
909 {
910 	struct btrfs_space_info *space_info = to_space_info(kobj);
911 	ssize_t ret;
912 
913 	spin_lock(&space_info->lock);
914 	ret = sysfs_emit(buf, "%d\n", btrfs_calc_reclaim_threshold(space_info));
915 	spin_unlock(&space_info->lock);
916 	return ret;
917 }
918 
919 static ssize_t btrfs_sinfo_bg_reclaim_threshold_store(struct kobject *kobj,
920 						      struct kobj_attribute *a,
921 						      const char *buf, size_t len)
922 {
923 	struct btrfs_space_info *space_info = to_space_info(kobj);
924 	int thresh;
925 	int ret;
926 
927 	if (READ_ONCE(space_info->dynamic_reclaim))
928 		return -EINVAL;
929 
930 	ret = kstrtoint(buf, 10, &thresh);
931 	if (ret)
932 		return ret;
933 
934 	if (thresh < 0 || thresh > 100)
935 		return -EINVAL;
936 
937 	WRITE_ONCE(space_info->bg_reclaim_threshold, thresh);
938 
939 	return len;
940 }
941 
942 BTRFS_ATTR_RW(space_info, bg_reclaim_threshold,
943 	      btrfs_sinfo_bg_reclaim_threshold_show,
944 	      btrfs_sinfo_bg_reclaim_threshold_store);
945 
946 static ssize_t btrfs_sinfo_dynamic_reclaim_show(struct kobject *kobj,
947 						struct kobj_attribute *a,
948 						char *buf)
949 {
950 	struct btrfs_space_info *space_info = to_space_info(kobj);
951 
952 	return sysfs_emit(buf, "%d\n", READ_ONCE(space_info->dynamic_reclaim));
953 }
954 
955 static ssize_t btrfs_sinfo_dynamic_reclaim_store(struct kobject *kobj,
956 						 struct kobj_attribute *a,
957 						 const char *buf, size_t len)
958 {
959 	struct btrfs_space_info *space_info = to_space_info(kobj);
960 	int dynamic_reclaim;
961 	int ret;
962 
963 	ret = kstrtoint(buf, 10, &dynamic_reclaim);
964 	if (ret)
965 		return ret;
966 
967 	if (dynamic_reclaim < 0)
968 		return -EINVAL;
969 
970 	WRITE_ONCE(space_info->dynamic_reclaim, dynamic_reclaim != 0);
971 
972 	return len;
973 }
974 
975 BTRFS_ATTR_RW(space_info, dynamic_reclaim,
976 	      btrfs_sinfo_dynamic_reclaim_show,
977 	      btrfs_sinfo_dynamic_reclaim_store);
978 
979 static ssize_t btrfs_sinfo_periodic_reclaim_show(struct kobject *kobj,
980 						struct kobj_attribute *a,
981 						char *buf)
982 {
983 	struct btrfs_space_info *space_info = to_space_info(kobj);
984 
985 	return sysfs_emit(buf, "%d\n", READ_ONCE(space_info->periodic_reclaim));
986 }
987 
988 static ssize_t btrfs_sinfo_periodic_reclaim_store(struct kobject *kobj,
989 						 struct kobj_attribute *a,
990 						 const char *buf, size_t len)
991 {
992 	struct btrfs_space_info *space_info = to_space_info(kobj);
993 	int periodic_reclaim;
994 	int ret;
995 
996 	ret = kstrtoint(buf, 10, &periodic_reclaim);
997 	if (ret)
998 		return ret;
999 
1000 	if (periodic_reclaim < 0)
1001 		return -EINVAL;
1002 
1003 	WRITE_ONCE(space_info->periodic_reclaim, periodic_reclaim != 0);
1004 
1005 	return len;
1006 }
1007 
1008 BTRFS_ATTR_RW(space_info, periodic_reclaim,
1009 	      btrfs_sinfo_periodic_reclaim_show,
1010 	      btrfs_sinfo_periodic_reclaim_store);
1011 
1012 /*
1013  * Allocation information about block group types.
1014  *
1015  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/
1016  */
1017 static struct attribute *space_info_attrs[] = {
1018 	BTRFS_ATTR_PTR(space_info, flags),
1019 	BTRFS_ATTR_PTR(space_info, total_bytes),
1020 	BTRFS_ATTR_PTR(space_info, bytes_used),
1021 	BTRFS_ATTR_PTR(space_info, bytes_pinned),
1022 	BTRFS_ATTR_PTR(space_info, bytes_reserved),
1023 	BTRFS_ATTR_PTR(space_info, bytes_may_use),
1024 	BTRFS_ATTR_PTR(space_info, bytes_readonly),
1025 	BTRFS_ATTR_PTR(space_info, bytes_zone_unusable),
1026 	BTRFS_ATTR_PTR(space_info, disk_used),
1027 	BTRFS_ATTR_PTR(space_info, disk_total),
1028 	BTRFS_ATTR_PTR(space_info, bg_reclaim_threshold),
1029 	BTRFS_ATTR_PTR(space_info, dynamic_reclaim),
1030 	BTRFS_ATTR_PTR(space_info, chunk_size),
1031 	BTRFS_ATTR_PTR(space_info, size_classes),
1032 	BTRFS_ATTR_PTR(space_info, reclaim_count),
1033 	BTRFS_ATTR_PTR(space_info, reclaim_bytes),
1034 	BTRFS_ATTR_PTR(space_info, reclaim_errors),
1035 	BTRFS_ATTR_PTR(space_info, periodic_reclaim),
1036 #ifdef CONFIG_BTRFS_DEBUG
1037 	BTRFS_ATTR_PTR(space_info, force_chunk_alloc),
1038 #endif
1039 	NULL,
1040 };
1041 ATTRIBUTE_GROUPS(space_info);
1042 
1043 static void space_info_release(struct kobject *kobj)
1044 {
1045 	struct btrfs_space_info *sinfo = to_space_info(kobj);
1046 	kfree(sinfo);
1047 }
1048 
1049 static const struct kobj_type space_info_ktype = {
1050 	.sysfs_ops = &kobj_sysfs_ops,
1051 	.release = space_info_release,
1052 	.default_groups = space_info_groups,
1053 };
1054 
1055 /*
1056  * Allocation information about block groups.
1057  *
1058  * Path: /sys/fs/btrfs/<uuid>/allocation/
1059  */
1060 static const struct attribute *allocation_attrs[] = {
1061 	BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
1062 	BTRFS_ATTR_PTR(allocation, global_rsv_size),
1063 	NULL,
1064 };
1065 
1066 static ssize_t btrfs_label_show(struct kobject *kobj,
1067 				struct kobj_attribute *a, char *buf)
1068 {
1069 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1070 	char *label = fs_info->super_copy->label;
1071 	ssize_t ret;
1072 
1073 	spin_lock(&fs_info->super_lock);
1074 	ret = sysfs_emit(buf, label[0] ? "%s\n" : "%s", label);
1075 	spin_unlock(&fs_info->super_lock);
1076 
1077 	return ret;
1078 }
1079 
1080 static ssize_t btrfs_label_store(struct kobject *kobj,
1081 				 struct kobj_attribute *a,
1082 				 const char *buf, size_t len)
1083 {
1084 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1085 	size_t p_len;
1086 
1087 	if (!fs_info)
1088 		return -EPERM;
1089 
1090 	if (sb_rdonly(fs_info->sb))
1091 		return -EROFS;
1092 
1093 	/*
1094 	 * p_len is the len until the first occurrence of either
1095 	 * '\n' or '\0'
1096 	 */
1097 	p_len = strcspn(buf, "\n");
1098 
1099 	if (p_len >= BTRFS_LABEL_SIZE)
1100 		return -EINVAL;
1101 
1102 	spin_lock(&fs_info->super_lock);
1103 	memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
1104 	memcpy(fs_info->super_copy->label, buf, p_len);
1105 	spin_unlock(&fs_info->super_lock);
1106 
1107 	/*
1108 	 * We don't want to do full transaction commit from inside sysfs
1109 	 */
1110 	set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
1111 	wake_up_process(fs_info->transaction_kthread);
1112 
1113 	return len;
1114 }
1115 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
1116 
1117 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
1118 				struct kobj_attribute *a, char *buf)
1119 {
1120 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1121 
1122 	return sysfs_emit(buf, "%u\n", fs_info->nodesize);
1123 }
1124 
1125 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
1126 
1127 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
1128 				struct kobj_attribute *a, char *buf)
1129 {
1130 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1131 
1132 	return sysfs_emit(buf, "%u\n", fs_info->sectorsize);
1133 }
1134 
1135 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
1136 
1137 static ssize_t btrfs_commit_stats_show(struct kobject *kobj,
1138 				       struct kobj_attribute *a, char *buf)
1139 {
1140 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1141 
1142 	return sysfs_emit(buf,
1143 		"commits %llu\n"
1144 		"last_commit_ms %llu\n"
1145 		"max_commit_ms %llu\n"
1146 		"total_commit_ms %llu\n",
1147 		fs_info->commit_stats.commit_count,
1148 		div_u64(fs_info->commit_stats.last_commit_dur, NSEC_PER_MSEC),
1149 		div_u64(fs_info->commit_stats.max_commit_dur, NSEC_PER_MSEC),
1150 		div_u64(fs_info->commit_stats.total_commit_dur, NSEC_PER_MSEC));
1151 }
1152 
1153 static ssize_t btrfs_commit_stats_store(struct kobject *kobj,
1154 					struct kobj_attribute *a,
1155 					const char *buf, size_t len)
1156 {
1157 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1158 	unsigned long val;
1159 	int ret;
1160 
1161 	if (!fs_info)
1162 		return -EPERM;
1163 
1164 	if (!capable(CAP_SYS_RESOURCE))
1165 		return -EPERM;
1166 
1167 	ret = kstrtoul(buf, 10, &val);
1168 	if (ret)
1169 		return ret;
1170 	if (val)
1171 		return -EINVAL;
1172 
1173 	WRITE_ONCE(fs_info->commit_stats.max_commit_dur, 0);
1174 
1175 	return len;
1176 }
1177 BTRFS_ATTR_RW(, commit_stats, btrfs_commit_stats_show, btrfs_commit_stats_store);
1178 
1179 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
1180 				struct kobj_attribute *a, char *buf)
1181 {
1182 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1183 
1184 	return sysfs_emit(buf, "%u\n", fs_info->sectorsize);
1185 }
1186 
1187 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
1188 
1189 static ssize_t quota_override_show(struct kobject *kobj,
1190 				   struct kobj_attribute *a, char *buf)
1191 {
1192 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1193 	int quota_override;
1194 
1195 	quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1196 	return sysfs_emit(buf, "%d\n", quota_override);
1197 }
1198 
1199 static ssize_t quota_override_store(struct kobject *kobj,
1200 				    struct kobj_attribute *a,
1201 				    const char *buf, size_t len)
1202 {
1203 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1204 	unsigned long knob;
1205 	int err;
1206 
1207 	if (!fs_info)
1208 		return -EPERM;
1209 
1210 	if (!capable(CAP_SYS_RESOURCE))
1211 		return -EPERM;
1212 
1213 	err = kstrtoul(buf, 10, &knob);
1214 	if (err)
1215 		return err;
1216 	if (knob > 1)
1217 		return -EINVAL;
1218 
1219 	if (knob)
1220 		set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1221 	else
1222 		clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1223 
1224 	return len;
1225 }
1226 
1227 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
1228 
1229 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
1230 				struct kobj_attribute *a, char *buf)
1231 {
1232 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1233 
1234 	return sysfs_emit(buf, "%pU\n", fs_info->fs_devices->metadata_uuid);
1235 }
1236 
1237 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
1238 
1239 static ssize_t btrfs_checksum_show(struct kobject *kobj,
1240 				   struct kobj_attribute *a, char *buf)
1241 {
1242 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1243 	u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
1244 
1245 	return sysfs_emit(buf, "%s (%s)\n",
1246 			  btrfs_super_csum_name(csum_type),
1247 			  crypto_shash_driver_name(fs_info->csum_shash));
1248 }
1249 
1250 BTRFS_ATTR(, checksum, btrfs_checksum_show);
1251 
1252 static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
1253 		struct kobj_attribute *a, char *buf)
1254 {
1255 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1256 	const char *str;
1257 
1258 	switch (READ_ONCE(fs_info->exclusive_operation)) {
1259 		case  BTRFS_EXCLOP_NONE:
1260 			str = "none\n";
1261 			break;
1262 		case BTRFS_EXCLOP_BALANCE:
1263 			str = "balance\n";
1264 			break;
1265 		case BTRFS_EXCLOP_BALANCE_PAUSED:
1266 			str = "balance paused\n";
1267 			break;
1268 		case BTRFS_EXCLOP_DEV_ADD:
1269 			str = "device add\n";
1270 			break;
1271 		case BTRFS_EXCLOP_DEV_REMOVE:
1272 			str = "device remove\n";
1273 			break;
1274 		case BTRFS_EXCLOP_DEV_REPLACE:
1275 			str = "device replace\n";
1276 			break;
1277 		case BTRFS_EXCLOP_RESIZE:
1278 			str = "resize\n";
1279 			break;
1280 		case BTRFS_EXCLOP_SWAP_ACTIVATE:
1281 			str = "swap activate\n";
1282 			break;
1283 		default:
1284 			str = "UNKNOWN\n";
1285 			break;
1286 	}
1287 	return sysfs_emit(buf, "%s", str);
1288 }
1289 BTRFS_ATTR(, exclusive_operation, btrfs_exclusive_operation_show);
1290 
1291 static ssize_t btrfs_generation_show(struct kobject *kobj,
1292 				     struct kobj_attribute *a, char *buf)
1293 {
1294 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1295 
1296 	return sysfs_emit(buf, "%llu\n", btrfs_get_fs_generation(fs_info));
1297 }
1298 BTRFS_ATTR(, generation, btrfs_generation_show);
1299 
1300 static ssize_t btrfs_temp_fsid_show(struct kobject *kobj,
1301 				    struct kobj_attribute *a, char *buf)
1302 {
1303 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1304 
1305 	return sysfs_emit(buf, "%d\n", fs_info->fs_devices->temp_fsid);
1306 }
1307 BTRFS_ATTR(, temp_fsid, btrfs_temp_fsid_show);
1308 
1309 static const char *btrfs_read_policy_name[] = {
1310 	"pid",
1311 #ifdef CONFIG_BTRFS_EXPERIMENTAL
1312 	"round-robin",
1313 	"devid",
1314 #endif
1315 };
1316 
1317 #ifdef CONFIG_BTRFS_EXPERIMENTAL
1318 
1319 /* Global module configuration parameters. */
1320 static char *read_policy;
1321 char *btrfs_get_mod_read_policy(void)
1322 {
1323 	return read_policy;
1324 }
1325 
1326 /* Set perms to 0, disable /sys/module/btrfs/parameter/read_policy interface. */
1327 module_param(read_policy, charp, 0);
1328 MODULE_PARM_DESC(read_policy,
1329 "Global read policy: pid (default), round-robin[:<min_contig_read>], devid[:<devid>]");
1330 #endif
1331 
1332 int btrfs_read_policy_to_enum(const char *str, s64 *value_ret)
1333 {
1334 	char param[32];
1335 	char __maybe_unused *value_str;
1336 
1337 	if (!str || strlen(str) == 0)
1338 		return 0;
1339 
1340 	strscpy(param, str);
1341 
1342 #ifdef CONFIG_BTRFS_EXPERIMENTAL
1343 	/* Separate value from input in policy:value format. */
1344 	value_str = strchr(param, ':');
1345 	if (value_str) {
1346 		char *retptr;
1347 
1348 		*value_str = 0;
1349 		value_str++;
1350 		if (!value_ret)
1351 			return -EINVAL;
1352 
1353 		*value_ret = memparse(value_str, &retptr);
1354 		/* There could be any trailing typos after the value. */
1355 		retptr = skip_spaces(retptr);
1356 		if (*retptr != 0 || *value_ret <= 0)
1357 			return -EINVAL;
1358 	}
1359 #endif
1360 
1361 	return sysfs_match_string(btrfs_read_policy_name, param);
1362 }
1363 
1364 #ifdef CONFIG_BTRFS_EXPERIMENTAL
1365 int __init btrfs_read_policy_init(void)
1366 {
1367 	s64 value;
1368 
1369 	if (btrfs_read_policy_to_enum(read_policy, &value) == -EINVAL) {
1370 		btrfs_err(NULL, "invalid read policy or value %s", read_policy);
1371 		return -EINVAL;
1372 	}
1373 
1374 	return 0;
1375 }
1376 #endif
1377 
1378 static ssize_t btrfs_read_policy_show(struct kobject *kobj,
1379 				      struct kobj_attribute *a, char *buf)
1380 {
1381 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1382 	const enum btrfs_read_policy policy = READ_ONCE(fs_devices->read_policy);
1383 	ssize_t ret = 0;
1384 	int i;
1385 
1386 	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1387 		if (ret != 0)
1388 			ret += sysfs_emit_at(buf, ret, " ");
1389 
1390 		if (i == policy)
1391 			ret += sysfs_emit_at(buf, ret, "[");
1392 
1393 		ret += sysfs_emit_at(buf, ret, "%s", btrfs_read_policy_name[i]);
1394 
1395 #ifdef CONFIG_BTRFS_EXPERIMENTAL
1396 		if (i == BTRFS_READ_POLICY_RR)
1397 			ret += sysfs_emit_at(buf, ret, ":%u",
1398 					     READ_ONCE(fs_devices->rr_min_contig_read));
1399 
1400 		if (i == BTRFS_READ_POLICY_DEVID)
1401 			ret += sysfs_emit_at(buf, ret, ":%llu",
1402 					     READ_ONCE(fs_devices->read_devid));
1403 #endif
1404 		if (i == policy)
1405 			ret += sysfs_emit_at(buf, ret, "]");
1406 	}
1407 
1408 	ret += sysfs_emit_at(buf, ret, "\n");
1409 
1410 	return ret;
1411 }
1412 
1413 static ssize_t btrfs_read_policy_store(struct kobject *kobj,
1414 				       struct kobj_attribute *a,
1415 				       const char *buf, size_t len)
1416 {
1417 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1418 	int index;
1419 	s64 value = -1;
1420 
1421 	index = btrfs_read_policy_to_enum(buf, &value);
1422 	if (index < 0)
1423 		return -EINVAL;
1424 
1425 #ifdef CONFIG_BTRFS_EXPERIMENTAL
1426 	/* If moving from RR then disable collecting fs stats. */
1427 	if (fs_devices->read_policy == BTRFS_READ_POLICY_RR && index != BTRFS_READ_POLICY_RR)
1428 		fs_devices->collect_fs_stats = false;
1429 
1430 	if (index == BTRFS_READ_POLICY_RR) {
1431 		if (value != -1) {
1432 			const u32 sectorsize = fs_devices->fs_info->sectorsize;
1433 
1434 			if (!IS_ALIGNED(value, sectorsize)) {
1435 				u64 temp_value = round_up(value, sectorsize);
1436 
1437 				btrfs_debug(fs_devices->fs_info,
1438 "read_policy: min contig read %lld should be multiple of sectorsize %u, rounded to %llu",
1439 					  value, sectorsize, temp_value);
1440 				value = temp_value;
1441 			}
1442 		} else {
1443 			value = BTRFS_DEFAULT_RR_MIN_CONTIG_READ;
1444 		}
1445 
1446 		if (index != READ_ONCE(fs_devices->read_policy) ||
1447 		    value != READ_ONCE(fs_devices->rr_min_contig_read)) {
1448 			WRITE_ONCE(fs_devices->read_policy, index);
1449 			WRITE_ONCE(fs_devices->rr_min_contig_read, value);
1450 
1451 			btrfs_info(fs_devices->fs_info, "read policy set to '%s:%lld'",
1452 				   btrfs_read_policy_name[index], value);
1453 		}
1454 
1455 		fs_devices->collect_fs_stats = true;
1456 
1457 		return len;
1458 	}
1459 
1460 	if (index == BTRFS_READ_POLICY_DEVID) {
1461 		if (value != -1) {
1462 			BTRFS_DEV_LOOKUP_ARGS(args);
1463 
1464 			/* Validate input devid. */
1465 			args.devid = value;
1466 			if (btrfs_find_device(fs_devices, &args) == NULL)
1467 				return -EINVAL;
1468 		} else {
1469 			/* Set default devid to the devid of the latest device. */
1470 			value = fs_devices->latest_dev->devid;
1471 		}
1472 
1473 		if (index != READ_ONCE(fs_devices->read_policy) ||
1474 		    value != READ_ONCE(fs_devices->read_devid)) {
1475 			WRITE_ONCE(fs_devices->read_policy, index);
1476 			WRITE_ONCE(fs_devices->read_devid, value);
1477 
1478 			btrfs_info(fs_devices->fs_info, "read policy set to '%s:%llu'",
1479 				   btrfs_read_policy_name[index], value);
1480 		}
1481 
1482 		return len;
1483 	}
1484 #endif
1485 	if (index != READ_ONCE(fs_devices->read_policy)) {
1486 		WRITE_ONCE(fs_devices->read_policy, index);
1487 		btrfs_info(fs_devices->fs_info, "read policy set to '%s'",
1488 			   btrfs_read_policy_name[index]);
1489 	}
1490 
1491 	return len;
1492 }
1493 BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store);
1494 
1495 static ssize_t btrfs_bg_reclaim_threshold_show(struct kobject *kobj,
1496 					       struct kobj_attribute *a,
1497 					       char *buf)
1498 {
1499 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1500 
1501 	return sysfs_emit(buf, "%d\n", READ_ONCE(fs_info->bg_reclaim_threshold));
1502 }
1503 
1504 static ssize_t btrfs_bg_reclaim_threshold_store(struct kobject *kobj,
1505 						struct kobj_attribute *a,
1506 						const char *buf, size_t len)
1507 {
1508 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1509 	int thresh;
1510 	int ret;
1511 
1512 	ret = kstrtoint(buf, 10, &thresh);
1513 	if (ret)
1514 		return ret;
1515 
1516 #ifdef CONFIG_BTRFS_DEBUG
1517 	if (thresh != 0 && (thresh > 100))
1518 		return -EINVAL;
1519 #else
1520 	if (thresh != 0 && (thresh <= 50 || thresh > 100))
1521 		return -EINVAL;
1522 #endif
1523 
1524 	WRITE_ONCE(fs_info->bg_reclaim_threshold, thresh);
1525 
1526 	return len;
1527 }
1528 BTRFS_ATTR_RW(, bg_reclaim_threshold, btrfs_bg_reclaim_threshold_show,
1529 	      btrfs_bg_reclaim_threshold_store);
1530 
1531 #ifdef CONFIG_BTRFS_EXPERIMENTAL
1532 static ssize_t btrfs_offload_csum_show(struct kobject *kobj,
1533 				       struct kobj_attribute *a, char *buf)
1534 {
1535 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1536 
1537 	switch (READ_ONCE(fs_devices->offload_csum_mode)) {
1538 	case BTRFS_OFFLOAD_CSUM_AUTO:
1539 		return sysfs_emit(buf, "auto\n");
1540 	case BTRFS_OFFLOAD_CSUM_FORCE_ON:
1541 		return sysfs_emit(buf, "1\n");
1542 	case BTRFS_OFFLOAD_CSUM_FORCE_OFF:
1543 		return sysfs_emit(buf, "0\n");
1544 	default:
1545 		WARN_ON(1);
1546 		return -EINVAL;
1547 	}
1548 }
1549 
1550 static ssize_t btrfs_offload_csum_store(struct kobject *kobj,
1551 					struct kobj_attribute *a, const char *buf,
1552 					size_t len)
1553 {
1554 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1555 	int ret;
1556 	bool val;
1557 
1558 	ret = kstrtobool(buf, &val);
1559 	if (ret == 0)
1560 		WRITE_ONCE(fs_devices->offload_csum_mode,
1561 			   val ? BTRFS_OFFLOAD_CSUM_FORCE_ON : BTRFS_OFFLOAD_CSUM_FORCE_OFF);
1562 	else if (ret == -EINVAL && sysfs_streq(buf, "auto"))
1563 		WRITE_ONCE(fs_devices->offload_csum_mode, BTRFS_OFFLOAD_CSUM_AUTO);
1564 	else
1565 		return -EINVAL;
1566 
1567 	return len;
1568 }
1569 BTRFS_ATTR_RW(, offload_csum, btrfs_offload_csum_show, btrfs_offload_csum_store);
1570 #endif
1571 
1572 /*
1573  * Per-filesystem information and stats.
1574  *
1575  * Path: /sys/fs/btrfs/<uuid>/
1576  */
1577 static const struct attribute *btrfs_attrs[] = {
1578 	BTRFS_ATTR_PTR(, label),
1579 	BTRFS_ATTR_PTR(, nodesize),
1580 	BTRFS_ATTR_PTR(, sectorsize),
1581 	BTRFS_ATTR_PTR(, clone_alignment),
1582 	BTRFS_ATTR_PTR(, quota_override),
1583 	BTRFS_ATTR_PTR(, metadata_uuid),
1584 	BTRFS_ATTR_PTR(, checksum),
1585 	BTRFS_ATTR_PTR(, exclusive_operation),
1586 	BTRFS_ATTR_PTR(, generation),
1587 	BTRFS_ATTR_PTR(, read_policy),
1588 	BTRFS_ATTR_PTR(, bg_reclaim_threshold),
1589 	BTRFS_ATTR_PTR(, commit_stats),
1590 	BTRFS_ATTR_PTR(, temp_fsid),
1591 #ifdef CONFIG_BTRFS_EXPERIMENTAL
1592 	BTRFS_ATTR_PTR(, offload_csum),
1593 #endif
1594 	NULL,
1595 };
1596 
1597 static void btrfs_release_fsid_kobj(struct kobject *kobj)
1598 {
1599 	struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
1600 
1601 	memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
1602 	complete(&fs_devs->kobj_unregister);
1603 }
1604 
1605 static const struct kobj_type btrfs_ktype = {
1606 	.sysfs_ops	= &kobj_sysfs_ops,
1607 	.release	= btrfs_release_fsid_kobj,
1608 };
1609 
1610 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
1611 {
1612 	if (kobj->ktype != &btrfs_ktype)
1613 		return NULL;
1614 	return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
1615 }
1616 
1617 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
1618 {
1619 	if (kobj->ktype != &btrfs_ktype)
1620 		return NULL;
1621 	return to_fs_devs(kobj)->fs_info;
1622 }
1623 
1624 static struct kobject *get_btrfs_kobj(struct kobject *kobj)
1625 {
1626 	while (kobj) {
1627 		if (kobj->ktype == &btrfs_ktype)
1628 			return kobj;
1629 		kobj = kobj->parent;
1630 	}
1631 	return NULL;
1632 }
1633 
1634 #define NUM_FEATURE_BITS 64
1635 #define BTRFS_FEATURE_NAME_MAX 13
1636 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
1637 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
1638 
1639 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names) ==
1640 	      ARRAY_SIZE(btrfs_feature_attrs));
1641 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names[0]) ==
1642 	      ARRAY_SIZE(btrfs_feature_attrs[0]));
1643 
1644 static const u64 supported_feature_masks[FEAT_MAX] = {
1645 	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
1646 	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
1647 	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
1648 };
1649 
1650 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
1651 {
1652 	int set;
1653 
1654 	for (set = 0; set < FEAT_MAX; set++) {
1655 		int i;
1656 		struct attribute *attrs[2];
1657 		struct attribute_group agroup = {
1658 			.name = "features",
1659 			.attrs = attrs,
1660 		};
1661 		u64 features = get_features(fs_info, set);
1662 		features &= ~supported_feature_masks[set];
1663 
1664 		if (!features)
1665 			continue;
1666 
1667 		attrs[1] = NULL;
1668 		for (i = 0; i < NUM_FEATURE_BITS; i++) {
1669 			struct btrfs_feature_attr *fa;
1670 
1671 			if (!(features & (1ULL << i)))
1672 				continue;
1673 
1674 			fa = &btrfs_feature_attrs[set][i];
1675 			attrs[0] = &fa->kobj_attr.attr;
1676 			if (add) {
1677 				int ret;
1678 				ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
1679 							&agroup);
1680 				if (ret)
1681 					return ret;
1682 			} else
1683 				sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
1684 						    &agroup);
1685 		}
1686 
1687 	}
1688 	return 0;
1689 }
1690 
1691 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1692 {
1693 	if (fs_devs->devinfo_kobj) {
1694 		kobject_del(fs_devs->devinfo_kobj);
1695 		kobject_put(fs_devs->devinfo_kobj);
1696 		fs_devs->devinfo_kobj = NULL;
1697 	}
1698 
1699 	if (fs_devs->devices_kobj) {
1700 		kobject_del(fs_devs->devices_kobj);
1701 		kobject_put(fs_devs->devices_kobj);
1702 		fs_devs->devices_kobj = NULL;
1703 	}
1704 
1705 	if (fs_devs->fsid_kobj.state_initialized) {
1706 		kobject_del(&fs_devs->fsid_kobj);
1707 		kobject_put(&fs_devs->fsid_kobj);
1708 		wait_for_completion(&fs_devs->kobj_unregister);
1709 	}
1710 }
1711 
1712 /* when fs_devs is NULL it will remove all fsid kobject */
1713 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1714 {
1715 	struct list_head *fs_uuids = btrfs_get_fs_uuids();
1716 
1717 	if (fs_devs) {
1718 		__btrfs_sysfs_remove_fsid(fs_devs);
1719 		return;
1720 	}
1721 
1722 	list_for_each_entry(fs_devs, fs_uuids, fs_list) {
1723 		__btrfs_sysfs_remove_fsid(fs_devs);
1724 	}
1725 }
1726 
1727 static void btrfs_sysfs_remove_fs_devices(struct btrfs_fs_devices *fs_devices)
1728 {
1729 	struct btrfs_device *device;
1730 	struct btrfs_fs_devices *seed;
1731 
1732 	list_for_each_entry(device, &fs_devices->devices, dev_list)
1733 		btrfs_sysfs_remove_device(device);
1734 
1735 	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1736 		list_for_each_entry(device, &seed->devices, dev_list)
1737 			btrfs_sysfs_remove_device(device);
1738 	}
1739 }
1740 
1741 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
1742 {
1743 	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1744 
1745 	sysfs_remove_link(fsid_kobj, "bdi");
1746 
1747 	if (fs_info->space_info_kobj) {
1748 		sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
1749 		kobject_del(fs_info->space_info_kobj);
1750 		kobject_put(fs_info->space_info_kobj);
1751 	}
1752 	if (fs_info->discard_kobj) {
1753 		sysfs_remove_files(fs_info->discard_kobj, discard_attrs);
1754 		kobject_del(fs_info->discard_kobj);
1755 		kobject_put(fs_info->discard_kobj);
1756 	}
1757 #ifdef CONFIG_BTRFS_DEBUG
1758 	if (fs_info->debug_kobj) {
1759 		sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1760 		kobject_del(fs_info->debug_kobj);
1761 		kobject_put(fs_info->debug_kobj);
1762 	}
1763 #endif
1764 	addrm_unknown_feature_attrs(fs_info, false);
1765 	sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1766 	sysfs_remove_files(fsid_kobj, btrfs_attrs);
1767 	btrfs_sysfs_remove_fs_devices(fs_info->fs_devices);
1768 }
1769 
1770 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
1771 	[FEAT_COMPAT]	 = "compat",
1772 	[FEAT_COMPAT_RO] = "compat_ro",
1773 	[FEAT_INCOMPAT]	 = "incompat",
1774 };
1775 
1776 const char *btrfs_feature_set_name(enum btrfs_feature_set set)
1777 {
1778 	return btrfs_feature_set_names[set];
1779 }
1780 
1781 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
1782 {
1783 	size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
1784 	int len = 0;
1785 	int i;
1786 	char *str;
1787 
1788 	str = kmalloc(bufsize, GFP_KERNEL);
1789 	if (!str)
1790 		return str;
1791 
1792 	for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1793 		const char *name;
1794 
1795 		if (!(flags & (1ULL << i)))
1796 			continue;
1797 
1798 		name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
1799 		len += scnprintf(str + len, bufsize - len, "%s%s",
1800 				len ? "," : "", name);
1801 	}
1802 
1803 	return str;
1804 }
1805 
1806 static void init_feature_attrs(void)
1807 {
1808 	struct btrfs_feature_attr *fa;
1809 	int set, i;
1810 
1811 	memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
1812 	memset(btrfs_unknown_feature_names, 0,
1813 	       sizeof(btrfs_unknown_feature_names));
1814 
1815 	for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
1816 		struct btrfs_feature_attr *sfa;
1817 		struct attribute *a = btrfs_supported_feature_attrs[i];
1818 		int bit;
1819 		sfa = attr_to_btrfs_feature_attr(a);
1820 		bit = ilog2(sfa->feature_bit);
1821 		fa = &btrfs_feature_attrs[sfa->feature_set][bit];
1822 
1823 		fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
1824 	}
1825 
1826 	for (set = 0; set < FEAT_MAX; set++) {
1827 		for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1828 			char *name = btrfs_unknown_feature_names[set][i];
1829 			fa = &btrfs_feature_attrs[set][i];
1830 
1831 			if (fa->kobj_attr.attr.name)
1832 				continue;
1833 
1834 			snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
1835 				 btrfs_feature_set_names[set], i);
1836 
1837 			fa->kobj_attr.attr.name = name;
1838 			fa->kobj_attr.attr.mode = S_IRUGO;
1839 			fa->feature_set = set;
1840 			fa->feature_bit = 1ULL << i;
1841 		}
1842 	}
1843 }
1844 
1845 /*
1846  * Create a sysfs entry for a given block group type at path
1847  * /sys/fs/btrfs/UUID/allocation/data/TYPE
1848  */
1849 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
1850 {
1851 	struct btrfs_fs_info *fs_info = cache->fs_info;
1852 	struct btrfs_space_info *space_info = cache->space_info;
1853 	struct raid_kobject *rkobj;
1854 	const int index = btrfs_bg_flags_to_raid_index(cache->flags);
1855 	unsigned int nofs_flag;
1856 	int ret;
1857 
1858 	/*
1859 	 * Setup a NOFS context because kobject_add(), deep in its call chain,
1860 	 * does GFP_KERNEL allocations, and we are often called in a context
1861 	 * where if reclaim is triggered we can deadlock (we are either holding
1862 	 * a transaction handle or some lock required for a transaction
1863 	 * commit).
1864 	 */
1865 	nofs_flag = memalloc_nofs_save();
1866 
1867 	rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
1868 	if (!rkobj) {
1869 		memalloc_nofs_restore(nofs_flag);
1870 		btrfs_warn(cache->fs_info,
1871 				"couldn't alloc memory for raid level kobject");
1872 		return;
1873 	}
1874 
1875 	rkobj->flags = cache->flags;
1876 	kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
1877 
1878 	/*
1879 	 * We call this either on mount, or if we've created a block group for a
1880 	 * new index type while running (i.e. when restriping).  The running
1881 	 * case is tricky because we could race with other threads, so we need
1882 	 * to have this check to make sure we didn't already init the kobject.
1883 	 *
1884 	 * We don't have to protect on the free side because it only happens on
1885 	 * unmount.
1886 	 */
1887 	spin_lock(&space_info->lock);
1888 	if (space_info->block_group_kobjs[index]) {
1889 		spin_unlock(&space_info->lock);
1890 		kobject_put(&rkobj->kobj);
1891 		return;
1892 	} else {
1893 		space_info->block_group_kobjs[index] = &rkobj->kobj;
1894 	}
1895 	spin_unlock(&space_info->lock);
1896 
1897 	ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
1898 			  btrfs_bg_type_to_raid_name(rkobj->flags));
1899 	memalloc_nofs_restore(nofs_flag);
1900 	if (ret) {
1901 		spin_lock(&space_info->lock);
1902 		space_info->block_group_kobjs[index] = NULL;
1903 		spin_unlock(&space_info->lock);
1904 		kobject_put(&rkobj->kobj);
1905 		btrfs_warn(fs_info,
1906 			"failed to add kobject for block cache, ignoring");
1907 		return;
1908 	}
1909 }
1910 
1911 /*
1912  * Remove sysfs directories for all block group types of a given space info and
1913  * the space info as well
1914  */
1915 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
1916 {
1917 	int i;
1918 
1919 	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1920 		struct kobject *kobj;
1921 
1922 		kobj = space_info->block_group_kobjs[i];
1923 		space_info->block_group_kobjs[i] = NULL;
1924 		if (kobj) {
1925 			kobject_del(kobj);
1926 			kobject_put(kobj);
1927 		}
1928 	}
1929 	kobject_del(&space_info->kobj);
1930 	kobject_put(&space_info->kobj);
1931 }
1932 
1933 static const char *alloc_name(struct btrfs_space_info *space_info)
1934 {
1935 	u64 flags = space_info->flags;
1936 
1937 	switch (flags) {
1938 	case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
1939 		return "mixed";
1940 	case BTRFS_BLOCK_GROUP_METADATA:
1941 		switch (space_info->subgroup_id) {
1942 		case BTRFS_SUB_GROUP_PRIMARY:
1943 			return "metadata";
1944 		case BTRFS_SUB_GROUP_TREELOG:
1945 			return "metadata-treelog";
1946 		default:
1947 			WARN_ON_ONCE(1);
1948 			return "metadata (unknown sub-group)";
1949 		}
1950 	case BTRFS_BLOCK_GROUP_DATA:
1951 		switch (space_info->subgroup_id) {
1952 		case BTRFS_SUB_GROUP_PRIMARY:
1953 			return "data";
1954 		case BTRFS_SUB_GROUP_DATA_RELOC:
1955 			return "data-reloc";
1956 		default:
1957 			WARN_ON_ONCE(1);
1958 			return "data (unknown sub-group)";
1959 		}
1960 	case BTRFS_BLOCK_GROUP_SYSTEM:
1961 		ASSERT(space_info->subgroup_id == BTRFS_SUB_GROUP_PRIMARY);
1962 		return "system";
1963 	default:
1964 		WARN_ON(1);
1965 		return "invalid-combination";
1966 	}
1967 }
1968 
1969 /*
1970  * Create a sysfs entry for a space info type at path
1971  * /sys/fs/btrfs/UUID/allocation/TYPE
1972  */
1973 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
1974 				    struct btrfs_space_info *space_info)
1975 {
1976 	int ret;
1977 
1978 	ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
1979 				   fs_info->space_info_kobj, "%s",
1980 				   alloc_name(space_info));
1981 	if (ret) {
1982 		kobject_put(&space_info->kobj);
1983 		return ret;
1984 	}
1985 
1986 	return 0;
1987 }
1988 
1989 void btrfs_sysfs_remove_device(struct btrfs_device *device)
1990 {
1991 	struct kobject *devices_kobj;
1992 
1993 	/*
1994 	 * Seed fs_devices devices_kobj aren't used, fetch kobject from the
1995 	 * fs_info::fs_devices.
1996 	 */
1997 	devices_kobj = device->fs_info->fs_devices->devices_kobj;
1998 	ASSERT(devices_kobj);
1999 
2000 	if (device->bdev)
2001 		sysfs_remove_link(devices_kobj, bdev_kobj(device->bdev)->name);
2002 
2003 	if (device->devid_kobj.state_initialized) {
2004 		kobject_del(&device->devid_kobj);
2005 		kobject_put(&device->devid_kobj);
2006 		wait_for_completion(&device->kobj_unregister);
2007 	}
2008 }
2009 
2010 static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj,
2011 					         struct kobj_attribute *a,
2012 					         char *buf)
2013 {
2014 	int val;
2015 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
2016 						   devid_kobj);
2017 
2018 	val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
2019 
2020 	return sysfs_emit(buf, "%d\n", val);
2021 }
2022 BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show);
2023 
2024 static ssize_t btrfs_devinfo_missing_show(struct kobject *kobj,
2025 					struct kobj_attribute *a, char *buf)
2026 {
2027 	int val;
2028 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
2029 						   devid_kobj);
2030 
2031 	val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
2032 
2033 	return sysfs_emit(buf, "%d\n", val);
2034 }
2035 BTRFS_ATTR(devid, missing, btrfs_devinfo_missing_show);
2036 
2037 static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj,
2038 					         struct kobj_attribute *a,
2039 					         char *buf)
2040 {
2041 	int val;
2042 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
2043 						   devid_kobj);
2044 
2045 	val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
2046 
2047 	return sysfs_emit(buf, "%d\n", val);
2048 }
2049 BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show);
2050 
2051 static ssize_t btrfs_devinfo_scrub_speed_max_show(struct kobject *kobj,
2052 					     struct kobj_attribute *a,
2053 					     char *buf)
2054 {
2055 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
2056 						   devid_kobj);
2057 
2058 	return sysfs_emit(buf, "%llu\n", READ_ONCE(device->scrub_speed_max));
2059 }
2060 
2061 static ssize_t btrfs_devinfo_scrub_speed_max_store(struct kobject *kobj,
2062 					      struct kobj_attribute *a,
2063 					      const char *buf, size_t len)
2064 {
2065 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
2066 						   devid_kobj);
2067 	char *endptr;
2068 	unsigned long long limit;
2069 
2070 	limit = memparse(buf, &endptr);
2071 	/* There could be trailing '\n', also catch any typos after the value. */
2072 	endptr = skip_spaces(endptr);
2073 	if (*endptr != 0)
2074 		return -EINVAL;
2075 	WRITE_ONCE(device->scrub_speed_max, limit);
2076 	return len;
2077 }
2078 BTRFS_ATTR_RW(devid, scrub_speed_max, btrfs_devinfo_scrub_speed_max_show,
2079 	      btrfs_devinfo_scrub_speed_max_store);
2080 
2081 static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj,
2082 					    struct kobj_attribute *a, char *buf)
2083 {
2084 	int val;
2085 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
2086 						   devid_kobj);
2087 
2088 	val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
2089 
2090 	return sysfs_emit(buf, "%d\n", val);
2091 }
2092 BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show);
2093 
2094 static ssize_t btrfs_devinfo_fsid_show(struct kobject *kobj,
2095 				       struct kobj_attribute *a, char *buf)
2096 {
2097 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
2098 						   devid_kobj);
2099 
2100 	return sysfs_emit(buf, "%pU\n", device->fs_devices->fsid);
2101 }
2102 BTRFS_ATTR(devid, fsid, btrfs_devinfo_fsid_show);
2103 
2104 static ssize_t btrfs_devinfo_error_stats_show(struct kobject *kobj,
2105 		struct kobj_attribute *a, char *buf)
2106 {
2107 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
2108 						   devid_kobj);
2109 
2110 	if (!device->dev_stats_valid)
2111 		return sysfs_emit(buf, "invalid\n");
2112 
2113 	/*
2114 	 * Print all at once so we get a snapshot of all values from the same
2115 	 * time. Keep them in sync and in order of definition of
2116 	 * btrfs_dev_stat_values.
2117 	 */
2118 	return sysfs_emit(buf,
2119 		"write_errs %d\n"
2120 		"read_errs %d\n"
2121 		"flush_errs %d\n"
2122 		"corruption_errs %d\n"
2123 		"generation_errs %d\n",
2124 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_WRITE_ERRS),
2125 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_READ_ERRS),
2126 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_FLUSH_ERRS),
2127 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_CORRUPTION_ERRS),
2128 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_GENERATION_ERRS));
2129 }
2130 BTRFS_ATTR(devid, error_stats, btrfs_devinfo_error_stats_show);
2131 
2132 /*
2133  * Information about one device.
2134  *
2135  * Path: /sys/fs/btrfs/<uuid>/devinfo/<devid>/
2136  */
2137 static struct attribute *devid_attrs[] = {
2138 	BTRFS_ATTR_PTR(devid, error_stats),
2139 	BTRFS_ATTR_PTR(devid, fsid),
2140 	BTRFS_ATTR_PTR(devid, in_fs_metadata),
2141 	BTRFS_ATTR_PTR(devid, missing),
2142 	BTRFS_ATTR_PTR(devid, replace_target),
2143 	BTRFS_ATTR_PTR(devid, scrub_speed_max),
2144 	BTRFS_ATTR_PTR(devid, writeable),
2145 	NULL
2146 };
2147 ATTRIBUTE_GROUPS(devid);
2148 
2149 static void btrfs_release_devid_kobj(struct kobject *kobj)
2150 {
2151 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
2152 						   devid_kobj);
2153 
2154 	memset(&device->devid_kobj, 0, sizeof(struct kobject));
2155 	complete(&device->kobj_unregister);
2156 }
2157 
2158 static const struct kobj_type devid_ktype = {
2159 	.sysfs_ops	= &kobj_sysfs_ops,
2160 	.default_groups = devid_groups,
2161 	.release	= btrfs_release_devid_kobj,
2162 };
2163 
2164 int btrfs_sysfs_add_device(struct btrfs_device *device)
2165 {
2166 	int ret;
2167 	unsigned int nofs_flag;
2168 	struct kobject *devices_kobj;
2169 	struct kobject *devinfo_kobj;
2170 
2171 	/*
2172 	 * Make sure we use the fs_info::fs_devices to fetch the kobjects even
2173 	 * for the seed fs_devices
2174 	 */
2175 	devices_kobj = device->fs_info->fs_devices->devices_kobj;
2176 	devinfo_kobj = device->fs_info->fs_devices->devinfo_kobj;
2177 	ASSERT(devices_kobj);
2178 	ASSERT(devinfo_kobj);
2179 
2180 	nofs_flag = memalloc_nofs_save();
2181 
2182 	if (device->bdev) {
2183 		struct kobject *disk_kobj = bdev_kobj(device->bdev);
2184 
2185 		ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
2186 		if (ret) {
2187 			btrfs_warn(device->fs_info,
2188 				"creating sysfs device link for devid %llu failed: %d",
2189 				device->devid, ret);
2190 			goto out;
2191 		}
2192 	}
2193 
2194 	init_completion(&device->kobj_unregister);
2195 	ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype,
2196 				   devinfo_kobj, "%llu", device->devid);
2197 	if (ret) {
2198 		kobject_put(&device->devid_kobj);
2199 		btrfs_warn(device->fs_info,
2200 			   "devinfo init for devid %llu failed: %d",
2201 			   device->devid, ret);
2202 	}
2203 
2204 out:
2205 	memalloc_nofs_restore(nofs_flag);
2206 	return ret;
2207 }
2208 
2209 static int btrfs_sysfs_add_fs_devices(struct btrfs_fs_devices *fs_devices)
2210 {
2211 	int ret;
2212 	struct btrfs_device *device;
2213 	struct btrfs_fs_devices *seed;
2214 
2215 	list_for_each_entry(device, &fs_devices->devices, dev_list) {
2216 		ret = btrfs_sysfs_add_device(device);
2217 		if (ret)
2218 			goto fail;
2219 	}
2220 
2221 	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
2222 		list_for_each_entry(device, &seed->devices, dev_list) {
2223 			ret = btrfs_sysfs_add_device(device);
2224 			if (ret)
2225 				goto fail;
2226 		}
2227 	}
2228 
2229 	return 0;
2230 
2231 fail:
2232 	btrfs_sysfs_remove_fs_devices(fs_devices);
2233 	return ret;
2234 }
2235 
2236 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
2237 {
2238 	int ret;
2239 
2240 	ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
2241 	if (ret)
2242 		pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
2243 			action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
2244 			&disk_to_dev(bdev->bd_disk)->kobj);
2245 }
2246 
2247 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices)
2248 
2249 {
2250 	char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2251 
2252 	/*
2253 	 * Sprouting changes fsid of the mounted filesystem, rename the fsid
2254 	 * directory
2255 	 */
2256 	snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fs_devices->fsid);
2257 	if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
2258 		btrfs_warn(fs_devices->fs_info,
2259 				"sysfs: failed to create fsid for sprout");
2260 }
2261 
2262 void btrfs_sysfs_update_devid(struct btrfs_device *device)
2263 {
2264 	char tmp[24];
2265 
2266 	snprintf(tmp, sizeof(tmp), "%llu", device->devid);
2267 
2268 	if (kobject_rename(&device->devid_kobj, tmp))
2269 		btrfs_warn(device->fs_devices->fs_info,
2270 			   "sysfs: failed to update devid for %llu",
2271 			   device->devid);
2272 }
2273 
2274 /* /sys/fs/btrfs/ entry */
2275 static struct kset *btrfs_kset;
2276 
2277 /*
2278  * Creates:
2279  *		/sys/fs/btrfs/UUID
2280  *
2281  * Can be called by the device discovery thread.
2282  */
2283 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
2284 {
2285 	int error;
2286 
2287 	init_completion(&fs_devs->kobj_unregister);
2288 	fs_devs->fsid_kobj.kset = btrfs_kset;
2289 	error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
2290 				     "%pU", fs_devs->fsid);
2291 	if (error) {
2292 		kobject_put(&fs_devs->fsid_kobj);
2293 		return error;
2294 	}
2295 
2296 	fs_devs->devices_kobj = kobject_create_and_add("devices",
2297 						       &fs_devs->fsid_kobj);
2298 	if (!fs_devs->devices_kobj) {
2299 		btrfs_err(fs_devs->fs_info,
2300 			  "failed to init sysfs device interface");
2301 		btrfs_sysfs_remove_fsid(fs_devs);
2302 		return -ENOMEM;
2303 	}
2304 
2305 	fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
2306 						       &fs_devs->fsid_kobj);
2307 	if (!fs_devs->devinfo_kobj) {
2308 		btrfs_err(fs_devs->fs_info,
2309 			  "failed to init sysfs devinfo kobject");
2310 		btrfs_sysfs_remove_fsid(fs_devs);
2311 		return -ENOMEM;
2312 	}
2313 
2314 	return 0;
2315 }
2316 
2317 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
2318 {
2319 	int error;
2320 	struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
2321 	struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
2322 
2323 	error = btrfs_sysfs_add_fs_devices(fs_devs);
2324 	if (error)
2325 		return error;
2326 
2327 	error = sysfs_create_files(fsid_kobj, btrfs_attrs);
2328 	if (error) {
2329 		btrfs_sysfs_remove_fs_devices(fs_devs);
2330 		return error;
2331 	}
2332 
2333 	error = sysfs_create_group(fsid_kobj,
2334 				   &btrfs_feature_attr_group);
2335 	if (error)
2336 		goto failure;
2337 
2338 #ifdef CONFIG_BTRFS_DEBUG
2339 	fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
2340 	if (!fs_info->debug_kobj) {
2341 		error = -ENOMEM;
2342 		goto failure;
2343 	}
2344 
2345 	error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
2346 	if (error)
2347 		goto failure;
2348 #endif
2349 
2350 	/* Discard directory */
2351 	fs_info->discard_kobj = kobject_create_and_add("discard", fsid_kobj);
2352 	if (!fs_info->discard_kobj) {
2353 		error = -ENOMEM;
2354 		goto failure;
2355 	}
2356 
2357 	error = sysfs_create_files(fs_info->discard_kobj, discard_attrs);
2358 	if (error)
2359 		goto failure;
2360 
2361 	error = addrm_unknown_feature_attrs(fs_info, true);
2362 	if (error)
2363 		goto failure;
2364 
2365 	error = sysfs_create_link(fsid_kobj, &fs_info->sb->s_bdi->dev->kobj, "bdi");
2366 	if (error)
2367 		goto failure;
2368 
2369 	fs_info->space_info_kobj = kobject_create_and_add("allocation",
2370 						  fsid_kobj);
2371 	if (!fs_info->space_info_kobj) {
2372 		error = -ENOMEM;
2373 		goto failure;
2374 	}
2375 
2376 	error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
2377 	if (error)
2378 		goto failure;
2379 
2380 	return 0;
2381 failure:
2382 	btrfs_sysfs_remove_mounted(fs_info);
2383 	return error;
2384 }
2385 
2386 static ssize_t qgroup_enabled_show(struct kobject *qgroups_kobj,
2387 				   struct kobj_attribute *a,
2388 				   char *buf)
2389 {
2390 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2391 	bool enabled;
2392 
2393 	spin_lock(&fs_info->qgroup_lock);
2394 	enabled = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON;
2395 	spin_unlock(&fs_info->qgroup_lock);
2396 
2397 	return sysfs_emit(buf, "%d\n", enabled);
2398 }
2399 BTRFS_ATTR(qgroups, enabled, qgroup_enabled_show);
2400 
2401 static ssize_t qgroup_mode_show(struct kobject *qgroups_kobj,
2402 				struct kobj_attribute *a,
2403 				char *buf)
2404 {
2405 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2406 	ssize_t ret = 0;
2407 
2408 	spin_lock(&fs_info->qgroup_lock);
2409 	ASSERT(btrfs_qgroup_enabled(fs_info));
2410 	switch (btrfs_qgroup_mode(fs_info)) {
2411 	case BTRFS_QGROUP_MODE_FULL:
2412 		ret = sysfs_emit(buf, "qgroup\n");
2413 		break;
2414 	case BTRFS_QGROUP_MODE_SIMPLE:
2415 		ret = sysfs_emit(buf, "squota\n");
2416 		break;
2417 	default:
2418 		btrfs_warn(fs_info, "unexpected qgroup mode %d\n",
2419 			   btrfs_qgroup_mode(fs_info));
2420 		break;
2421 	}
2422 	spin_unlock(&fs_info->qgroup_lock);
2423 
2424 	return ret;
2425 }
2426 BTRFS_ATTR(qgroups, mode, qgroup_mode_show);
2427 
2428 static ssize_t qgroup_inconsistent_show(struct kobject *qgroups_kobj,
2429 					struct kobj_attribute *a,
2430 					char *buf)
2431 {
2432 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2433 	bool inconsistent;
2434 
2435 	spin_lock(&fs_info->qgroup_lock);
2436 	inconsistent = (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT);
2437 	spin_unlock(&fs_info->qgroup_lock);
2438 
2439 	return sysfs_emit(buf, "%d\n", inconsistent);
2440 }
2441 BTRFS_ATTR(qgroups, inconsistent, qgroup_inconsistent_show);
2442 
2443 static ssize_t qgroup_drop_subtree_thres_show(struct kobject *qgroups_kobj,
2444 					      struct kobj_attribute *a,
2445 					      char *buf)
2446 {
2447 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2448 	u8 result;
2449 
2450 	spin_lock(&fs_info->qgroup_lock);
2451 	result = fs_info->qgroup_drop_subtree_thres;
2452 	spin_unlock(&fs_info->qgroup_lock);
2453 
2454 	return sysfs_emit(buf, "%d\n", result);
2455 }
2456 
2457 static ssize_t qgroup_drop_subtree_thres_store(struct kobject *qgroups_kobj,
2458 					       struct kobj_attribute *a,
2459 					       const char *buf, size_t len)
2460 {
2461 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2462 	u8 new_thres;
2463 	int ret;
2464 
2465 	ret = kstrtou8(buf, 10, &new_thres);
2466 	if (ret)
2467 		return -EINVAL;
2468 
2469 	if (new_thres > BTRFS_MAX_LEVEL)
2470 		return -EINVAL;
2471 
2472 	spin_lock(&fs_info->qgroup_lock);
2473 	fs_info->qgroup_drop_subtree_thres = new_thres;
2474 	spin_unlock(&fs_info->qgroup_lock);
2475 
2476 	return len;
2477 }
2478 BTRFS_ATTR_RW(qgroups, drop_subtree_threshold, qgroup_drop_subtree_thres_show,
2479 	      qgroup_drop_subtree_thres_store);
2480 
2481 /*
2482  * Qgroups global info
2483  *
2484  * Path: /sys/fs/btrfs/<uuid>/qgroups/
2485  */
2486 static struct attribute *qgroups_attrs[] = {
2487 	BTRFS_ATTR_PTR(qgroups, enabled),
2488 	BTRFS_ATTR_PTR(qgroups, inconsistent),
2489 	BTRFS_ATTR_PTR(qgroups, drop_subtree_threshold),
2490 	BTRFS_ATTR_PTR(qgroups, mode),
2491 	NULL
2492 };
2493 ATTRIBUTE_GROUPS(qgroups);
2494 
2495 static void qgroups_release(struct kobject *kobj)
2496 {
2497 	kfree(kobj);
2498 }
2499 
2500 static const struct kobj_type qgroups_ktype = {
2501 	.sysfs_ops = &kobj_sysfs_ops,
2502 	.default_groups = qgroups_groups,
2503 	.release = qgroups_release,
2504 };
2505 
2506 static inline struct btrfs_fs_info *qgroup_kobj_to_fs_info(struct kobject *kobj)
2507 {
2508 	return to_fs_info(kobj->parent->parent);
2509 }
2510 
2511 #define QGROUP_ATTR(_member, _show_name)					\
2512 static ssize_t btrfs_qgroup_show_##_member(struct kobject *qgroup_kobj,		\
2513 					   struct kobj_attribute *a,		\
2514 					   char *buf)				\
2515 {										\
2516 	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2517 	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2518 			struct btrfs_qgroup, kobj);				\
2519 	return btrfs_show_u64(&qgroup->_member, &fs_info->qgroup_lock, buf);	\
2520 }										\
2521 BTRFS_ATTR(qgroup, _show_name, btrfs_qgroup_show_##_member)
2522 
2523 #define QGROUP_RSV_ATTR(_name, _type)						\
2524 static ssize_t btrfs_qgroup_rsv_show_##_name(struct kobject *qgroup_kobj,	\
2525 					     struct kobj_attribute *a,		\
2526 					     char *buf)				\
2527 {										\
2528 	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2529 	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2530 			struct btrfs_qgroup, kobj);				\
2531 	return btrfs_show_u64(&qgroup->rsv.values[_type],			\
2532 			&fs_info->qgroup_lock, buf);				\
2533 }										\
2534 BTRFS_ATTR(qgroup, rsv_##_name, btrfs_qgroup_rsv_show_##_name)
2535 
2536 QGROUP_ATTR(rfer, referenced);
2537 QGROUP_ATTR(excl, exclusive);
2538 QGROUP_ATTR(max_rfer, max_referenced);
2539 QGROUP_ATTR(max_excl, max_exclusive);
2540 QGROUP_ATTR(lim_flags, limit_flags);
2541 QGROUP_RSV_ATTR(data, BTRFS_QGROUP_RSV_DATA);
2542 QGROUP_RSV_ATTR(meta_pertrans, BTRFS_QGROUP_RSV_META_PERTRANS);
2543 QGROUP_RSV_ATTR(meta_prealloc, BTRFS_QGROUP_RSV_META_PREALLOC);
2544 
2545 /*
2546  * Qgroup information.
2547  *
2548  * Path: /sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>/
2549  */
2550 static struct attribute *qgroup_attrs[] = {
2551 	BTRFS_ATTR_PTR(qgroup, referenced),
2552 	BTRFS_ATTR_PTR(qgroup, exclusive),
2553 	BTRFS_ATTR_PTR(qgroup, max_referenced),
2554 	BTRFS_ATTR_PTR(qgroup, max_exclusive),
2555 	BTRFS_ATTR_PTR(qgroup, limit_flags),
2556 	BTRFS_ATTR_PTR(qgroup, rsv_data),
2557 	BTRFS_ATTR_PTR(qgroup, rsv_meta_pertrans),
2558 	BTRFS_ATTR_PTR(qgroup, rsv_meta_prealloc),
2559 	NULL
2560 };
2561 ATTRIBUTE_GROUPS(qgroup);
2562 
2563 static void qgroup_release(struct kobject *kobj)
2564 {
2565 	struct btrfs_qgroup *qgroup = container_of(kobj, struct btrfs_qgroup, kobj);
2566 
2567 	memset(&qgroup->kobj, 0, sizeof(*kobj));
2568 }
2569 
2570 static const struct kobj_type qgroup_ktype = {
2571 	.sysfs_ops = &kobj_sysfs_ops,
2572 	.release = qgroup_release,
2573 	.default_groups = qgroup_groups,
2574 };
2575 
2576 int btrfs_sysfs_add_one_qgroup(struct btrfs_fs_info *fs_info,
2577 				struct btrfs_qgroup *qgroup)
2578 {
2579 	struct kobject *qgroups_kobj = fs_info->qgroups_kobj;
2580 	int ret;
2581 
2582 	if (btrfs_is_testing(fs_info))
2583 		return 0;
2584 	if (qgroup->kobj.state_initialized)
2585 		return 0;
2586 	if (!qgroups_kobj)
2587 		return -EINVAL;
2588 
2589 	ret = kobject_init_and_add(&qgroup->kobj, &qgroup_ktype, qgroups_kobj,
2590 			"%hu_%llu", btrfs_qgroup_level(qgroup->qgroupid),
2591 			btrfs_qgroup_subvolid(qgroup->qgroupid));
2592 	if (ret < 0)
2593 		kobject_put(&qgroup->kobj);
2594 
2595 	return ret;
2596 }
2597 
2598 void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info)
2599 {
2600 	struct btrfs_qgroup *qgroup;
2601 	struct btrfs_qgroup *next;
2602 
2603 	if (btrfs_is_testing(fs_info))
2604 		return;
2605 
2606 	rbtree_postorder_for_each_entry_safe(qgroup, next,
2607 					     &fs_info->qgroup_tree, node)
2608 		btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
2609 	if (fs_info->qgroups_kobj) {
2610 		kobject_del(fs_info->qgroups_kobj);
2611 		kobject_put(fs_info->qgroups_kobj);
2612 		fs_info->qgroups_kobj = NULL;
2613 	}
2614 }
2615 
2616 /* Called when qgroups get initialized, thus there is no need for locking */
2617 int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info)
2618 {
2619 	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2620 	struct btrfs_qgroup *qgroup;
2621 	struct btrfs_qgroup *next;
2622 	int ret = 0;
2623 
2624 	if (btrfs_is_testing(fs_info))
2625 		return 0;
2626 
2627 	ASSERT(fsid_kobj);
2628 	if (fs_info->qgroups_kobj)
2629 		return 0;
2630 
2631 	fs_info->qgroups_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
2632 	if (!fs_info->qgroups_kobj)
2633 		return -ENOMEM;
2634 
2635 	ret = kobject_init_and_add(fs_info->qgroups_kobj, &qgroups_ktype,
2636 				   fsid_kobj, "qgroups");
2637 	if (ret < 0)
2638 		goto out;
2639 
2640 	rbtree_postorder_for_each_entry_safe(qgroup, next,
2641 					     &fs_info->qgroup_tree, node) {
2642 		ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
2643 		if (ret < 0)
2644 			goto out;
2645 	}
2646 
2647 out:
2648 	if (ret < 0)
2649 		btrfs_sysfs_del_qgroups(fs_info);
2650 	return ret;
2651 }
2652 
2653 void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
2654 				struct btrfs_qgroup *qgroup)
2655 {
2656 	if (btrfs_is_testing(fs_info))
2657 		return;
2658 
2659 	if (qgroup->kobj.state_initialized) {
2660 		kobject_del(&qgroup->kobj);
2661 		kobject_put(&qgroup->kobj);
2662 	}
2663 }
2664 
2665 /*
2666  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
2667  * values in superblock. Call after any changes to incompat/compat_ro flags
2668  */
2669 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info)
2670 {
2671 	struct kobject *fsid_kobj;
2672 	int ret;
2673 
2674 	if (!fs_info)
2675 		return;
2676 
2677 	fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2678 	if (!fsid_kobj->state_initialized)
2679 		return;
2680 
2681 	ret = sysfs_update_group(fsid_kobj, &btrfs_feature_attr_group);
2682 	if (ret < 0)
2683 		btrfs_warn(fs_info,
2684 			   "failed to update /sys/fs/btrfs/%pU/features: %d",
2685 			   fs_info->fs_devices->fsid, ret);
2686 }
2687 
2688 int __init btrfs_init_sysfs(void)
2689 {
2690 	int ret;
2691 
2692 	btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
2693 	if (!btrfs_kset)
2694 		return -ENOMEM;
2695 
2696 	init_feature_attrs();
2697 	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2698 	if (ret)
2699 		goto out2;
2700 	ret = sysfs_merge_group(&btrfs_kset->kobj,
2701 				&btrfs_static_feature_attr_group);
2702 	if (ret)
2703 		goto out_remove_group;
2704 
2705 #ifdef CONFIG_BTRFS_DEBUG
2706 	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2707 	if (ret) {
2708 		sysfs_unmerge_group(&btrfs_kset->kobj,
2709 				    &btrfs_static_feature_attr_group);
2710 		goto out_remove_group;
2711 	}
2712 #endif
2713 
2714 	return 0;
2715 
2716 out_remove_group:
2717 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2718 out2:
2719 	kset_unregister(btrfs_kset);
2720 
2721 	return ret;
2722 }
2723 
2724 void __cold btrfs_exit_sysfs(void)
2725 {
2726 	sysfs_unmerge_group(&btrfs_kset->kobj,
2727 			    &btrfs_static_feature_attr_group);
2728 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2729 #ifdef CONFIG_BTRFS_DEBUG
2730 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2731 #endif
2732 	kset_unregister(btrfs_kset);
2733 }
2734