xref: /linux/fs/btrfs/sysfs.c (revision 72bea132f3680ee51e7ed2cee62892b6f5121909)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2007 Oracle.  All rights reserved.
4  */
5 
6 #include <linux/sched.h>
7 #include <linux/sched/mm.h>
8 #include <linux/slab.h>
9 #include <linux/spinlock.h>
10 #include <linux/completion.h>
11 #include <linux/bug.h>
12 #include <linux/list.h>
13 #include <crypto/hash.h>
14 #include "messages.h"
15 #include "ctree.h"
16 #include "discard.h"
17 #include "disk-io.h"
18 #include "send.h"
19 #include "transaction.h"
20 #include "sysfs.h"
21 #include "volumes.h"
22 #include "space-info.h"
23 #include "block-group.h"
24 #include "qgroup.h"
25 #include "misc.h"
26 #include "fs.h"
27 #include "accessors.h"
28 
29 /*
30  * Structure name                       Path
31  * --------------------------------------------------------------------------
32  * btrfs_supported_static_feature_attrs /sys/fs/btrfs/features
33  * btrfs_supported_feature_attrs	/sys/fs/btrfs/features and
34  *					/sys/fs/btrfs/<uuid>/features
35  * btrfs_attrs				/sys/fs/btrfs/<uuid>
36  * devid_attrs				/sys/fs/btrfs/<uuid>/devinfo/<devid>
37  * allocation_attrs			/sys/fs/btrfs/<uuid>/allocation
38  * qgroup_attrs				/sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>
39  * space_info_attrs			/sys/fs/btrfs/<uuid>/allocation/<bg-type>
40  * raid_attrs				/sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>
41  * discard_attrs			/sys/fs/btrfs/<uuid>/discard
42  *
43  * When built with BTRFS_CONFIG_DEBUG:
44  *
45  * btrfs_debug_feature_attrs		/sys/fs/btrfs/debug
46  * btrfs_debug_mount_attrs		/sys/fs/btrfs/<uuid>/debug
47  */
48 
49 struct btrfs_feature_attr {
50 	struct kobj_attribute kobj_attr;
51 	enum btrfs_feature_set feature_set;
52 	u64 feature_bit;
53 };
54 
55 /* For raid type sysfs entries */
56 struct raid_kobject {
57 	u64 flags;
58 	struct kobject kobj;
59 };
60 
61 #define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)			\
62 {									\
63 	.attr	= { .name = __stringify(_name), .mode = _mode },	\
64 	.show	= _show,						\
65 	.store	= _store,						\
66 }
67 
68 #define BTRFS_ATTR_W(_prefix, _name, _store)			        \
69 	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
70 			__INIT_KOBJ_ATTR(_name, 0200, NULL, _store)
71 
72 #define BTRFS_ATTR_RW(_prefix, _name, _show, _store)			\
73 	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
74 			__INIT_KOBJ_ATTR(_name, 0644, _show, _store)
75 
76 #define BTRFS_ATTR(_prefix, _name, _show)				\
77 	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
78 			__INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
79 
80 #define BTRFS_ATTR_PTR(_prefix, _name)					\
81 	(&btrfs_attr_##_prefix##_##_name.attr)
82 
83 #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
84 static struct btrfs_feature_attr btrfs_attr_features_##_name = {	     \
85 	.kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,			     \
86 				      btrfs_feature_attr_show,		     \
87 				      btrfs_feature_attr_store),	     \
88 	.feature_set	= _feature_set,					     \
89 	.feature_bit	= _feature_prefix ##_## _feature_bit,		     \
90 }
91 #define BTRFS_FEAT_ATTR_PTR(_name)					     \
92 	(&btrfs_attr_features_##_name.kobj_attr.attr)
93 
94 #define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
95 	BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
96 #define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
97 	BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
98 #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
99 	BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)
100 
101 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
102 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
103 static struct kobject *get_btrfs_kobj(struct kobject *kobj);
104 
105 static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
106 {
107 	return container_of(a, struct btrfs_feature_attr, kobj_attr);
108 }
109 
110 static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
111 {
112 	return container_of(attr, struct kobj_attribute, attr);
113 }
114 
115 static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
116 		struct attribute *attr)
117 {
118 	return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
119 }
120 
121 static u64 get_features(struct btrfs_fs_info *fs_info,
122 			enum btrfs_feature_set set)
123 {
124 	struct btrfs_super_block *disk_super = fs_info->super_copy;
125 	if (set == FEAT_COMPAT)
126 		return btrfs_super_compat_flags(disk_super);
127 	else if (set == FEAT_COMPAT_RO)
128 		return btrfs_super_compat_ro_flags(disk_super);
129 	else
130 		return btrfs_super_incompat_flags(disk_super);
131 }
132 
133 static void set_features(struct btrfs_fs_info *fs_info,
134 			 enum btrfs_feature_set set, u64 features)
135 {
136 	struct btrfs_super_block *disk_super = fs_info->super_copy;
137 	if (set == FEAT_COMPAT)
138 		btrfs_set_super_compat_flags(disk_super, features);
139 	else if (set == FEAT_COMPAT_RO)
140 		btrfs_set_super_compat_ro_flags(disk_super, features);
141 	else
142 		btrfs_set_super_incompat_flags(disk_super, features);
143 }
144 
145 static int can_modify_feature(struct btrfs_feature_attr *fa)
146 {
147 	int val = 0;
148 	u64 set, clear;
149 	switch (fa->feature_set) {
150 	case FEAT_COMPAT:
151 		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
152 		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
153 		break;
154 	case FEAT_COMPAT_RO:
155 		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
156 		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
157 		break;
158 	case FEAT_INCOMPAT:
159 		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
160 		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
161 		break;
162 	default:
163 		pr_warn("btrfs: sysfs: unknown feature set %d\n",
164 				fa->feature_set);
165 		return 0;
166 	}
167 
168 	if (set & fa->feature_bit)
169 		val |= 1;
170 	if (clear & fa->feature_bit)
171 		val |= 2;
172 
173 	return val;
174 }
175 
176 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
177 				       struct kobj_attribute *a, char *buf)
178 {
179 	int val = 0;
180 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
181 	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
182 	if (fs_info) {
183 		u64 features = get_features(fs_info, fa->feature_set);
184 		if (features & fa->feature_bit)
185 			val = 1;
186 	} else
187 		val = can_modify_feature(fa);
188 
189 	return sysfs_emit(buf, "%d\n", val);
190 }
191 
192 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
193 					struct kobj_attribute *a,
194 					const char *buf, size_t count)
195 {
196 	struct btrfs_fs_info *fs_info;
197 	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
198 	u64 features, set, clear;
199 	unsigned long val;
200 	int ret;
201 
202 	fs_info = to_fs_info(kobj);
203 	if (!fs_info)
204 		return -EPERM;
205 
206 	if (sb_rdonly(fs_info->sb))
207 		return -EROFS;
208 
209 	ret = kstrtoul(skip_spaces(buf), 0, &val);
210 	if (ret)
211 		return ret;
212 
213 	if (fa->feature_set == FEAT_COMPAT) {
214 		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
215 		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
216 	} else if (fa->feature_set == FEAT_COMPAT_RO) {
217 		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
218 		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
219 	} else {
220 		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
221 		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
222 	}
223 
224 	features = get_features(fs_info, fa->feature_set);
225 
226 	/* Nothing to do */
227 	if ((val && (features & fa->feature_bit)) ||
228 	    (!val && !(features & fa->feature_bit)))
229 		return count;
230 
231 	if ((val && !(set & fa->feature_bit)) ||
232 	    (!val && !(clear & fa->feature_bit))) {
233 		btrfs_info(fs_info,
234 			"%sabling feature %s on mounted fs is not supported.",
235 			val ? "En" : "Dis", fa->kobj_attr.attr.name);
236 		return -EPERM;
237 	}
238 
239 	btrfs_info(fs_info, "%s %s feature flag",
240 		   val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
241 
242 	spin_lock(&fs_info->super_lock);
243 	features = get_features(fs_info, fa->feature_set);
244 	if (val)
245 		features |= fa->feature_bit;
246 	else
247 		features &= ~fa->feature_bit;
248 	set_features(fs_info, fa->feature_set, features);
249 	spin_unlock(&fs_info->super_lock);
250 
251 	/*
252 	 * We don't want to do full transaction commit from inside sysfs
253 	 */
254 	set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
255 	wake_up_process(fs_info->transaction_kthread);
256 
257 	return count;
258 }
259 
260 static umode_t btrfs_feature_visible(struct kobject *kobj,
261 				     struct attribute *attr, int unused)
262 {
263 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
264 	umode_t mode = attr->mode;
265 
266 	if (fs_info) {
267 		struct btrfs_feature_attr *fa;
268 		u64 features;
269 
270 		fa = attr_to_btrfs_feature_attr(attr);
271 		features = get_features(fs_info, fa->feature_set);
272 
273 		if (can_modify_feature(fa))
274 			mode |= S_IWUSR;
275 		else if (!(features & fa->feature_bit))
276 			mode = 0;
277 	}
278 
279 	return mode;
280 }
281 
282 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
283 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
284 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
285 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
286 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
287 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
288 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
289 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
290 BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
291 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
292 BTRFS_FEAT_ATTR_COMPAT_RO(block_group_tree, BLOCK_GROUP_TREE);
293 BTRFS_FEAT_ATTR_INCOMPAT(raid1c34, RAID1C34);
294 BTRFS_FEAT_ATTR_INCOMPAT(simple_quota, SIMPLE_QUOTA);
295 #ifdef CONFIG_BLK_DEV_ZONED
296 BTRFS_FEAT_ATTR_INCOMPAT(zoned, ZONED);
297 #endif
298 #ifdef CONFIG_BTRFS_DEBUG
299 /* Remove once support for extent tree v2 is feature complete */
300 BTRFS_FEAT_ATTR_INCOMPAT(extent_tree_v2, EXTENT_TREE_V2);
301 /* Remove once support for raid stripe tree is feature complete. */
302 BTRFS_FEAT_ATTR_INCOMPAT(raid_stripe_tree, RAID_STRIPE_TREE);
303 #endif
304 #ifdef CONFIG_FS_VERITY
305 BTRFS_FEAT_ATTR_COMPAT_RO(verity, VERITY);
306 #endif
307 
308 /*
309  * Features which depend on feature bits and may differ between each fs.
310  *
311  * /sys/fs/btrfs/features      - all available features implemented by this version
312  * /sys/fs/btrfs/UUID/features - features of the fs which are enabled or
313  *                               can be changed on a mounted filesystem.
314  */
315 static struct attribute *btrfs_supported_feature_attrs[] = {
316 	BTRFS_FEAT_ATTR_PTR(default_subvol),
317 	BTRFS_FEAT_ATTR_PTR(mixed_groups),
318 	BTRFS_FEAT_ATTR_PTR(compress_lzo),
319 	BTRFS_FEAT_ATTR_PTR(compress_zstd),
320 	BTRFS_FEAT_ATTR_PTR(extended_iref),
321 	BTRFS_FEAT_ATTR_PTR(raid56),
322 	BTRFS_FEAT_ATTR_PTR(skinny_metadata),
323 	BTRFS_FEAT_ATTR_PTR(no_holes),
324 	BTRFS_FEAT_ATTR_PTR(metadata_uuid),
325 	BTRFS_FEAT_ATTR_PTR(free_space_tree),
326 	BTRFS_FEAT_ATTR_PTR(raid1c34),
327 	BTRFS_FEAT_ATTR_PTR(block_group_tree),
328 	BTRFS_FEAT_ATTR_PTR(simple_quota),
329 #ifdef CONFIG_BLK_DEV_ZONED
330 	BTRFS_FEAT_ATTR_PTR(zoned),
331 #endif
332 #ifdef CONFIG_BTRFS_DEBUG
333 	BTRFS_FEAT_ATTR_PTR(extent_tree_v2),
334 	BTRFS_FEAT_ATTR_PTR(raid_stripe_tree),
335 #endif
336 #ifdef CONFIG_FS_VERITY
337 	BTRFS_FEAT_ATTR_PTR(verity),
338 #endif
339 	NULL
340 };
341 
342 static const struct attribute_group btrfs_feature_attr_group = {
343 	.name = "features",
344 	.is_visible = btrfs_feature_visible,
345 	.attrs = btrfs_supported_feature_attrs,
346 };
347 
348 static ssize_t rmdir_subvol_show(struct kobject *kobj,
349 				 struct kobj_attribute *ka, char *buf)
350 {
351 	return sysfs_emit(buf, "0\n");
352 }
353 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
354 
355 static ssize_t supported_checksums_show(struct kobject *kobj,
356 					struct kobj_attribute *a, char *buf)
357 {
358 	ssize_t ret = 0;
359 	int i;
360 
361 	for (i = 0; i < btrfs_get_num_csums(); i++) {
362 		/*
363 		 * This "trick" only works as long as 'enum btrfs_csum_type' has
364 		 * no holes in it
365 		 */
366 		ret += sysfs_emit_at(buf, ret, "%s%s", (i == 0 ? "" : " "),
367 				     btrfs_super_csum_name(i));
368 
369 	}
370 
371 	ret += sysfs_emit_at(buf, ret, "\n");
372 	return ret;
373 }
374 BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);
375 
376 static ssize_t send_stream_version_show(struct kobject *kobj,
377 					struct kobj_attribute *ka, char *buf)
378 {
379 	return sysfs_emit(buf, "%d\n", BTRFS_SEND_STREAM_VERSION);
380 }
381 BTRFS_ATTR(static_feature, send_stream_version, send_stream_version_show);
382 
383 static const char *rescue_opts[] = {
384 	"usebackuproot",
385 	"nologreplay",
386 	"ignorebadroots",
387 	"ignoredatacsums",
388 	"all",
389 };
390 
391 static ssize_t supported_rescue_options_show(struct kobject *kobj,
392 					     struct kobj_attribute *a,
393 					     char *buf)
394 {
395 	ssize_t ret = 0;
396 	int i;
397 
398 	for (i = 0; i < ARRAY_SIZE(rescue_opts); i++)
399 		ret += sysfs_emit_at(buf, ret, "%s%s", (i ? " " : ""), rescue_opts[i]);
400 	ret += sysfs_emit_at(buf, ret, "\n");
401 	return ret;
402 }
403 BTRFS_ATTR(static_feature, supported_rescue_options,
404 	   supported_rescue_options_show);
405 
406 static ssize_t supported_sectorsizes_show(struct kobject *kobj,
407 					  struct kobj_attribute *a,
408 					  char *buf)
409 {
410 	ssize_t ret = 0;
411 
412 	/* An artificial limit to only support 4K and PAGE_SIZE */
413 	if (PAGE_SIZE > SZ_4K)
414 		ret += sysfs_emit_at(buf, ret, "%u ", SZ_4K);
415 	ret += sysfs_emit_at(buf, ret, "%lu\n", PAGE_SIZE);
416 
417 	return ret;
418 }
419 BTRFS_ATTR(static_feature, supported_sectorsizes,
420 	   supported_sectorsizes_show);
421 
422 static ssize_t acl_show(struct kobject *kobj, struct kobj_attribute *a, char *buf)
423 {
424 	return sysfs_emit(buf, "%d\n", IS_ENABLED(CONFIG_BTRFS_FS_POSIX_ACL));
425 }
426 BTRFS_ATTR(static_feature, acl, acl_show);
427 
428 static ssize_t temp_fsid_supported_show(struct kobject *kobj,
429 					struct kobj_attribute *a, char *buf)
430 {
431 	return sysfs_emit(buf, "0\n");
432 }
433 BTRFS_ATTR(static_feature, temp_fsid, temp_fsid_supported_show);
434 
435 /*
436  * Features which only depend on kernel version.
437  *
438  * These are listed in /sys/fs/btrfs/features along with
439  * btrfs_supported_feature_attrs.
440  */
441 static struct attribute *btrfs_supported_static_feature_attrs[] = {
442 	BTRFS_ATTR_PTR(static_feature, acl),
443 	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
444 	BTRFS_ATTR_PTR(static_feature, supported_checksums),
445 	BTRFS_ATTR_PTR(static_feature, send_stream_version),
446 	BTRFS_ATTR_PTR(static_feature, supported_rescue_options),
447 	BTRFS_ATTR_PTR(static_feature, supported_sectorsizes),
448 	BTRFS_ATTR_PTR(static_feature, temp_fsid),
449 	NULL
450 };
451 
452 static const struct attribute_group btrfs_static_feature_attr_group = {
453 	.name = "features",
454 	.attrs = btrfs_supported_static_feature_attrs,
455 };
456 
457 /*
458  * Discard statistics and tunables
459  */
460 #define discard_to_fs_info(_kobj)	to_fs_info(get_btrfs_kobj(_kobj))
461 
462 static ssize_t btrfs_discardable_bytes_show(struct kobject *kobj,
463 					    struct kobj_attribute *a,
464 					    char *buf)
465 {
466 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
467 
468 	return sysfs_emit(buf, "%lld\n",
469 			atomic64_read(&fs_info->discard_ctl.discardable_bytes));
470 }
471 BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
472 
473 static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
474 					      struct kobj_attribute *a,
475 					      char *buf)
476 {
477 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
478 
479 	return sysfs_emit(buf, "%d\n",
480 			atomic_read(&fs_info->discard_ctl.discardable_extents));
481 }
482 BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
483 
484 static ssize_t btrfs_discard_bitmap_bytes_show(struct kobject *kobj,
485 					       struct kobj_attribute *a,
486 					       char *buf)
487 {
488 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
489 
490 	return sysfs_emit(buf, "%llu\n",
491 			  fs_info->discard_ctl.discard_bitmap_bytes);
492 }
493 BTRFS_ATTR(discard, discard_bitmap_bytes, btrfs_discard_bitmap_bytes_show);
494 
495 static ssize_t btrfs_discard_bytes_saved_show(struct kobject *kobj,
496 					      struct kobj_attribute *a,
497 					      char *buf)
498 {
499 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
500 
501 	return sysfs_emit(buf, "%lld\n",
502 		atomic64_read(&fs_info->discard_ctl.discard_bytes_saved));
503 }
504 BTRFS_ATTR(discard, discard_bytes_saved, btrfs_discard_bytes_saved_show);
505 
506 static ssize_t btrfs_discard_extent_bytes_show(struct kobject *kobj,
507 					       struct kobj_attribute *a,
508 					       char *buf)
509 {
510 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
511 
512 	return sysfs_emit(buf, "%llu\n",
513 			  fs_info->discard_ctl.discard_extent_bytes);
514 }
515 BTRFS_ATTR(discard, discard_extent_bytes, btrfs_discard_extent_bytes_show);
516 
517 static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
518 					     struct kobj_attribute *a,
519 					     char *buf)
520 {
521 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
522 
523 	return sysfs_emit(buf, "%u\n",
524 			  READ_ONCE(fs_info->discard_ctl.iops_limit));
525 }
526 
527 static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
528 					      struct kobj_attribute *a,
529 					      const char *buf, size_t len)
530 {
531 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
532 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
533 	u32 iops_limit;
534 	int ret;
535 
536 	ret = kstrtou32(buf, 10, &iops_limit);
537 	if (ret)
538 		return -EINVAL;
539 
540 	WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
541 	btrfs_discard_calc_delay(discard_ctl);
542 	btrfs_discard_schedule_work(discard_ctl, true);
543 	return len;
544 }
545 BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
546 	      btrfs_discard_iops_limit_store);
547 
548 static ssize_t btrfs_discard_kbps_limit_show(struct kobject *kobj,
549 					     struct kobj_attribute *a,
550 					     char *buf)
551 {
552 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
553 
554 	return sysfs_emit(buf, "%u\n",
555 			  READ_ONCE(fs_info->discard_ctl.kbps_limit));
556 }
557 
558 static ssize_t btrfs_discard_kbps_limit_store(struct kobject *kobj,
559 					      struct kobj_attribute *a,
560 					      const char *buf, size_t len)
561 {
562 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
563 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
564 	u32 kbps_limit;
565 	int ret;
566 
567 	ret = kstrtou32(buf, 10, &kbps_limit);
568 	if (ret)
569 		return -EINVAL;
570 
571 	WRITE_ONCE(discard_ctl->kbps_limit, kbps_limit);
572 	btrfs_discard_schedule_work(discard_ctl, true);
573 	return len;
574 }
575 BTRFS_ATTR_RW(discard, kbps_limit, btrfs_discard_kbps_limit_show,
576 	      btrfs_discard_kbps_limit_store);
577 
578 static ssize_t btrfs_discard_max_discard_size_show(struct kobject *kobj,
579 						   struct kobj_attribute *a,
580 						   char *buf)
581 {
582 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
583 
584 	return sysfs_emit(buf, "%llu\n",
585 			  READ_ONCE(fs_info->discard_ctl.max_discard_size));
586 }
587 
588 static ssize_t btrfs_discard_max_discard_size_store(struct kobject *kobj,
589 						    struct kobj_attribute *a,
590 						    const char *buf, size_t len)
591 {
592 	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
593 	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
594 	u64 max_discard_size;
595 	int ret;
596 
597 	ret = kstrtou64(buf, 10, &max_discard_size);
598 	if (ret)
599 		return -EINVAL;
600 
601 	WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);
602 
603 	return len;
604 }
605 BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
606 	      btrfs_discard_max_discard_size_store);
607 
608 /*
609  * Per-filesystem stats for discard (when mounted with discard=async).
610  *
611  * Path: /sys/fs/btrfs/<uuid>/discard/
612  */
613 static const struct attribute *discard_attrs[] = {
614 	BTRFS_ATTR_PTR(discard, discardable_bytes),
615 	BTRFS_ATTR_PTR(discard, discardable_extents),
616 	BTRFS_ATTR_PTR(discard, discard_bitmap_bytes),
617 	BTRFS_ATTR_PTR(discard, discard_bytes_saved),
618 	BTRFS_ATTR_PTR(discard, discard_extent_bytes),
619 	BTRFS_ATTR_PTR(discard, iops_limit),
620 	BTRFS_ATTR_PTR(discard, kbps_limit),
621 	BTRFS_ATTR_PTR(discard, max_discard_size),
622 	NULL,
623 };
624 
625 #ifdef CONFIG_BTRFS_DEBUG
626 
627 /*
628  * Per-filesystem runtime debugging exported via sysfs.
629  *
630  * Path: /sys/fs/btrfs/UUID/debug/
631  */
632 static const struct attribute *btrfs_debug_mount_attrs[] = {
633 	NULL,
634 };
635 
636 /*
637  * Runtime debugging exported via sysfs, applies to all mounted filesystems.
638  *
639  * Path: /sys/fs/btrfs/debug
640  */
641 static struct attribute *btrfs_debug_feature_attrs[] = {
642 	NULL
643 };
644 
645 static const struct attribute_group btrfs_debug_feature_attr_group = {
646 	.name = "debug",
647 	.attrs = btrfs_debug_feature_attrs,
648 };
649 
650 #endif
651 
652 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
653 {
654 	u64 val;
655 	if (lock)
656 		spin_lock(lock);
657 	val = *value_ptr;
658 	if (lock)
659 		spin_unlock(lock);
660 	return sysfs_emit(buf, "%llu\n", val);
661 }
662 
663 static ssize_t global_rsv_size_show(struct kobject *kobj,
664 				    struct kobj_attribute *ka, char *buf)
665 {
666 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
667 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
668 	return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
669 }
670 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
671 
672 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
673 					struct kobj_attribute *a, char *buf)
674 {
675 	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
676 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
677 	return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
678 }
679 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
680 
681 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
682 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
683 
684 static ssize_t raid_bytes_show(struct kobject *kobj,
685 			       struct kobj_attribute *attr, char *buf);
686 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
687 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
688 
689 static ssize_t raid_bytes_show(struct kobject *kobj,
690 			       struct kobj_attribute *attr, char *buf)
691 
692 {
693 	struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
694 	struct btrfs_block_group *block_group;
695 	int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
696 	u64 val = 0;
697 
698 	down_read(&sinfo->groups_sem);
699 	list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
700 		if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
701 			val += block_group->length;
702 		else
703 			val += block_group->used;
704 	}
705 	up_read(&sinfo->groups_sem);
706 	return sysfs_emit(buf, "%llu\n", val);
707 }
708 
709 /*
710  * Allocation information about block group profiles.
711  *
712  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>/
713  */
714 static struct attribute *raid_attrs[] = {
715 	BTRFS_ATTR_PTR(raid, total_bytes),
716 	BTRFS_ATTR_PTR(raid, used_bytes),
717 	NULL
718 };
719 ATTRIBUTE_GROUPS(raid);
720 
721 static void release_raid_kobj(struct kobject *kobj)
722 {
723 	kfree(to_raid_kobj(kobj));
724 }
725 
726 static const struct kobj_type btrfs_raid_ktype = {
727 	.sysfs_ops = &kobj_sysfs_ops,
728 	.release = release_raid_kobj,
729 	.default_groups = raid_groups,
730 };
731 
732 #define SPACE_INFO_ATTR(field)						\
733 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,	\
734 					     struct kobj_attribute *a,	\
735 					     char *buf)			\
736 {									\
737 	struct btrfs_space_info *sinfo = to_space_info(kobj);		\
738 	return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);	\
739 }									\
740 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
741 
742 static ssize_t btrfs_chunk_size_show(struct kobject *kobj,
743 				     struct kobj_attribute *a, char *buf)
744 {
745 	struct btrfs_space_info *sinfo = to_space_info(kobj);
746 
747 	return sysfs_emit(buf, "%llu\n", READ_ONCE(sinfo->chunk_size));
748 }
749 
750 /*
751  * Store new chunk size in space info. Can be called on a read-only filesystem.
752  *
753  * If the new chunk size value is larger than 10% of free space it is reduced
754  * to match that limit. Alignment must be to 256M and the system chunk size
755  * cannot be set.
756  */
757 static ssize_t btrfs_chunk_size_store(struct kobject *kobj,
758 				      struct kobj_attribute *a,
759 				      const char *buf, size_t len)
760 {
761 	struct btrfs_space_info *space_info = to_space_info(kobj);
762 	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
763 	char *retptr;
764 	u64 val;
765 
766 	if (!capable(CAP_SYS_ADMIN))
767 		return -EPERM;
768 
769 	if (!fs_info->fs_devices)
770 		return -EINVAL;
771 
772 	if (btrfs_is_zoned(fs_info))
773 		return -EINVAL;
774 
775 	/* System block type must not be changed. */
776 	if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
777 		return -EPERM;
778 
779 	val = memparse(buf, &retptr);
780 	/* There could be trailing '\n', also catch any typos after the value */
781 	retptr = skip_spaces(retptr);
782 	if (*retptr != 0 || val == 0)
783 		return -EINVAL;
784 
785 	val = min(val, BTRFS_MAX_DATA_CHUNK_SIZE);
786 
787 	/* Limit stripe size to 10% of available space. */
788 	val = min(mult_perc(fs_info->fs_devices->total_rw_bytes, 10), val);
789 
790 	/* Must be multiple of 256M. */
791 	val &= ~((u64)SZ_256M - 1);
792 
793 	/* Must be at least 256M. */
794 	if (val < SZ_256M)
795 		return -EINVAL;
796 
797 	btrfs_update_space_info_chunk_size(space_info, val);
798 
799 	return len;
800 }
801 
802 static ssize_t btrfs_size_classes_show(struct kobject *kobj,
803 				       struct kobj_attribute *a, char *buf)
804 {
805 	struct btrfs_space_info *sinfo = to_space_info(kobj);
806 	struct btrfs_block_group *bg;
807 	u32 none = 0;
808 	u32 small = 0;
809 	u32 medium = 0;
810 	u32 large = 0;
811 
812 	for (int i = 0; i < BTRFS_NR_RAID_TYPES; ++i) {
813 		down_read(&sinfo->groups_sem);
814 		list_for_each_entry(bg, &sinfo->block_groups[i], list) {
815 			if (!btrfs_block_group_should_use_size_class(bg))
816 				continue;
817 			switch (bg->size_class) {
818 			case BTRFS_BG_SZ_NONE:
819 				none++;
820 				break;
821 			case BTRFS_BG_SZ_SMALL:
822 				small++;
823 				break;
824 			case BTRFS_BG_SZ_MEDIUM:
825 				medium++;
826 				break;
827 			case BTRFS_BG_SZ_LARGE:
828 				large++;
829 				break;
830 			}
831 		}
832 		up_read(&sinfo->groups_sem);
833 	}
834 	return sysfs_emit(buf, "none %u\n"
835 			       "small %u\n"
836 			       "medium %u\n"
837 			       "large %u\n",
838 			       none, small, medium, large);
839 }
840 
841 #ifdef CONFIG_BTRFS_DEBUG
842 /*
843  * Request chunk allocation with current chunk size.
844  */
845 static ssize_t btrfs_force_chunk_alloc_store(struct kobject *kobj,
846 					     struct kobj_attribute *a,
847 					     const char *buf, size_t len)
848 {
849 	struct btrfs_space_info *space_info = to_space_info(kobj);
850 	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
851 	struct btrfs_trans_handle *trans;
852 	bool val;
853 	int ret;
854 
855 	if (!capable(CAP_SYS_ADMIN))
856 		return -EPERM;
857 
858 	if (sb_rdonly(fs_info->sb))
859 		return -EROFS;
860 
861 	ret = kstrtobool(buf, &val);
862 	if (ret)
863 		return ret;
864 
865 	if (!val)
866 		return -EINVAL;
867 
868 	/*
869 	 * This is unsafe to be called from sysfs context and may cause
870 	 * unexpected problems.
871 	 */
872 	trans = btrfs_start_transaction(fs_info->tree_root, 0);
873 	if (IS_ERR(trans))
874 		return PTR_ERR(trans);
875 	ret = btrfs_force_chunk_alloc(trans, space_info->flags);
876 	btrfs_end_transaction(trans);
877 
878 	if (ret == 1)
879 		return len;
880 
881 	return -ENOSPC;
882 }
883 BTRFS_ATTR_W(space_info, force_chunk_alloc, btrfs_force_chunk_alloc_store);
884 
885 #endif
886 
887 SPACE_INFO_ATTR(flags);
888 SPACE_INFO_ATTR(total_bytes);
889 SPACE_INFO_ATTR(bytes_used);
890 SPACE_INFO_ATTR(bytes_pinned);
891 SPACE_INFO_ATTR(bytes_reserved);
892 SPACE_INFO_ATTR(bytes_may_use);
893 SPACE_INFO_ATTR(bytes_readonly);
894 SPACE_INFO_ATTR(bytes_zone_unusable);
895 SPACE_INFO_ATTR(disk_used);
896 SPACE_INFO_ATTR(disk_total);
897 BTRFS_ATTR_RW(space_info, chunk_size, btrfs_chunk_size_show, btrfs_chunk_size_store);
898 BTRFS_ATTR(space_info, size_classes, btrfs_size_classes_show);
899 
900 static ssize_t btrfs_sinfo_bg_reclaim_threshold_show(struct kobject *kobj,
901 						     struct kobj_attribute *a,
902 						     char *buf)
903 {
904 	struct btrfs_space_info *space_info = to_space_info(kobj);
905 
906 	return sysfs_emit(buf, "%d\n", READ_ONCE(space_info->bg_reclaim_threshold));
907 }
908 
909 static ssize_t btrfs_sinfo_bg_reclaim_threshold_store(struct kobject *kobj,
910 						      struct kobj_attribute *a,
911 						      const char *buf, size_t len)
912 {
913 	struct btrfs_space_info *space_info = to_space_info(kobj);
914 	int thresh;
915 	int ret;
916 
917 	ret = kstrtoint(buf, 10, &thresh);
918 	if (ret)
919 		return ret;
920 
921 	if (thresh < 0 || thresh > 100)
922 		return -EINVAL;
923 
924 	WRITE_ONCE(space_info->bg_reclaim_threshold, thresh);
925 
926 	return len;
927 }
928 
929 BTRFS_ATTR_RW(space_info, bg_reclaim_threshold,
930 	      btrfs_sinfo_bg_reclaim_threshold_show,
931 	      btrfs_sinfo_bg_reclaim_threshold_store);
932 
933 /*
934  * Allocation information about block group types.
935  *
936  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/
937  */
938 static struct attribute *space_info_attrs[] = {
939 	BTRFS_ATTR_PTR(space_info, flags),
940 	BTRFS_ATTR_PTR(space_info, total_bytes),
941 	BTRFS_ATTR_PTR(space_info, bytes_used),
942 	BTRFS_ATTR_PTR(space_info, bytes_pinned),
943 	BTRFS_ATTR_PTR(space_info, bytes_reserved),
944 	BTRFS_ATTR_PTR(space_info, bytes_may_use),
945 	BTRFS_ATTR_PTR(space_info, bytes_readonly),
946 	BTRFS_ATTR_PTR(space_info, bytes_zone_unusable),
947 	BTRFS_ATTR_PTR(space_info, disk_used),
948 	BTRFS_ATTR_PTR(space_info, disk_total),
949 	BTRFS_ATTR_PTR(space_info, bg_reclaim_threshold),
950 	BTRFS_ATTR_PTR(space_info, chunk_size),
951 	BTRFS_ATTR_PTR(space_info, size_classes),
952 #ifdef CONFIG_BTRFS_DEBUG
953 	BTRFS_ATTR_PTR(space_info, force_chunk_alloc),
954 #endif
955 	NULL,
956 };
957 ATTRIBUTE_GROUPS(space_info);
958 
959 static void space_info_release(struct kobject *kobj)
960 {
961 	struct btrfs_space_info *sinfo = to_space_info(kobj);
962 	kfree(sinfo);
963 }
964 
965 static const struct kobj_type space_info_ktype = {
966 	.sysfs_ops = &kobj_sysfs_ops,
967 	.release = space_info_release,
968 	.default_groups = space_info_groups,
969 };
970 
971 /*
972  * Allocation information about block groups.
973  *
974  * Path: /sys/fs/btrfs/<uuid>/allocation/
975  */
976 static const struct attribute *allocation_attrs[] = {
977 	BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
978 	BTRFS_ATTR_PTR(allocation, global_rsv_size),
979 	NULL,
980 };
981 
982 static ssize_t btrfs_label_show(struct kobject *kobj,
983 				struct kobj_attribute *a, char *buf)
984 {
985 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
986 	char *label = fs_info->super_copy->label;
987 	ssize_t ret;
988 
989 	spin_lock(&fs_info->super_lock);
990 	ret = sysfs_emit(buf, label[0] ? "%s\n" : "%s", label);
991 	spin_unlock(&fs_info->super_lock);
992 
993 	return ret;
994 }
995 
996 static ssize_t btrfs_label_store(struct kobject *kobj,
997 				 struct kobj_attribute *a,
998 				 const char *buf, size_t len)
999 {
1000 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1001 	size_t p_len;
1002 
1003 	if (!fs_info)
1004 		return -EPERM;
1005 
1006 	if (sb_rdonly(fs_info->sb))
1007 		return -EROFS;
1008 
1009 	/*
1010 	 * p_len is the len until the first occurrence of either
1011 	 * '\n' or '\0'
1012 	 */
1013 	p_len = strcspn(buf, "\n");
1014 
1015 	if (p_len >= BTRFS_LABEL_SIZE)
1016 		return -EINVAL;
1017 
1018 	spin_lock(&fs_info->super_lock);
1019 	memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
1020 	memcpy(fs_info->super_copy->label, buf, p_len);
1021 	spin_unlock(&fs_info->super_lock);
1022 
1023 	/*
1024 	 * We don't want to do full transaction commit from inside sysfs
1025 	 */
1026 	set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
1027 	wake_up_process(fs_info->transaction_kthread);
1028 
1029 	return len;
1030 }
1031 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
1032 
1033 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
1034 				struct kobj_attribute *a, char *buf)
1035 {
1036 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1037 
1038 	return sysfs_emit(buf, "%u\n", fs_info->super_copy->nodesize);
1039 }
1040 
1041 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
1042 
1043 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
1044 				struct kobj_attribute *a, char *buf)
1045 {
1046 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1047 
1048 	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
1049 }
1050 
1051 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
1052 
1053 static ssize_t btrfs_commit_stats_show(struct kobject *kobj,
1054 				       struct kobj_attribute *a, char *buf)
1055 {
1056 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1057 
1058 	return sysfs_emit(buf,
1059 		"commits %llu\n"
1060 		"last_commit_ms %llu\n"
1061 		"max_commit_ms %llu\n"
1062 		"total_commit_ms %llu\n",
1063 		fs_info->commit_stats.commit_count,
1064 		div_u64(fs_info->commit_stats.last_commit_dur, NSEC_PER_MSEC),
1065 		div_u64(fs_info->commit_stats.max_commit_dur, NSEC_PER_MSEC),
1066 		div_u64(fs_info->commit_stats.total_commit_dur, NSEC_PER_MSEC));
1067 }
1068 
1069 static ssize_t btrfs_commit_stats_store(struct kobject *kobj,
1070 					struct kobj_attribute *a,
1071 					const char *buf, size_t len)
1072 {
1073 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1074 	unsigned long val;
1075 	int ret;
1076 
1077 	if (!fs_info)
1078 		return -EPERM;
1079 
1080 	if (!capable(CAP_SYS_RESOURCE))
1081 		return -EPERM;
1082 
1083 	ret = kstrtoul(buf, 10, &val);
1084 	if (ret)
1085 		return ret;
1086 	if (val)
1087 		return -EINVAL;
1088 
1089 	WRITE_ONCE(fs_info->commit_stats.max_commit_dur, 0);
1090 
1091 	return len;
1092 }
1093 BTRFS_ATTR_RW(, commit_stats, btrfs_commit_stats_show, btrfs_commit_stats_store);
1094 
1095 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
1096 				struct kobj_attribute *a, char *buf)
1097 {
1098 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1099 
1100 	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
1101 }
1102 
1103 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
1104 
1105 static ssize_t quota_override_show(struct kobject *kobj,
1106 				   struct kobj_attribute *a, char *buf)
1107 {
1108 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1109 	int quota_override;
1110 
1111 	quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1112 	return sysfs_emit(buf, "%d\n", quota_override);
1113 }
1114 
1115 static ssize_t quota_override_store(struct kobject *kobj,
1116 				    struct kobj_attribute *a,
1117 				    const char *buf, size_t len)
1118 {
1119 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1120 	unsigned long knob;
1121 	int err;
1122 
1123 	if (!fs_info)
1124 		return -EPERM;
1125 
1126 	if (!capable(CAP_SYS_RESOURCE))
1127 		return -EPERM;
1128 
1129 	err = kstrtoul(buf, 10, &knob);
1130 	if (err)
1131 		return err;
1132 	if (knob > 1)
1133 		return -EINVAL;
1134 
1135 	if (knob)
1136 		set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1137 	else
1138 		clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1139 
1140 	return len;
1141 }
1142 
1143 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
1144 
1145 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
1146 				struct kobj_attribute *a, char *buf)
1147 {
1148 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1149 
1150 	return sysfs_emit(buf, "%pU\n", fs_info->fs_devices->metadata_uuid);
1151 }
1152 
1153 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
1154 
1155 static ssize_t btrfs_checksum_show(struct kobject *kobj,
1156 				   struct kobj_attribute *a, char *buf)
1157 {
1158 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1159 	u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
1160 
1161 	return sysfs_emit(buf, "%s (%s)\n",
1162 			  btrfs_super_csum_name(csum_type),
1163 			  crypto_shash_driver_name(fs_info->csum_shash));
1164 }
1165 
1166 BTRFS_ATTR(, checksum, btrfs_checksum_show);
1167 
1168 static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
1169 		struct kobj_attribute *a, char *buf)
1170 {
1171 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1172 	const char *str;
1173 
1174 	switch (READ_ONCE(fs_info->exclusive_operation)) {
1175 		case  BTRFS_EXCLOP_NONE:
1176 			str = "none\n";
1177 			break;
1178 		case BTRFS_EXCLOP_BALANCE:
1179 			str = "balance\n";
1180 			break;
1181 		case BTRFS_EXCLOP_BALANCE_PAUSED:
1182 			str = "balance paused\n";
1183 			break;
1184 		case BTRFS_EXCLOP_DEV_ADD:
1185 			str = "device add\n";
1186 			break;
1187 		case BTRFS_EXCLOP_DEV_REMOVE:
1188 			str = "device remove\n";
1189 			break;
1190 		case BTRFS_EXCLOP_DEV_REPLACE:
1191 			str = "device replace\n";
1192 			break;
1193 		case BTRFS_EXCLOP_RESIZE:
1194 			str = "resize\n";
1195 			break;
1196 		case BTRFS_EXCLOP_SWAP_ACTIVATE:
1197 			str = "swap activate\n";
1198 			break;
1199 		default:
1200 			str = "UNKNOWN\n";
1201 			break;
1202 	}
1203 	return sysfs_emit(buf, "%s", str);
1204 }
1205 BTRFS_ATTR(, exclusive_operation, btrfs_exclusive_operation_show);
1206 
1207 static ssize_t btrfs_generation_show(struct kobject *kobj,
1208 				     struct kobj_attribute *a, char *buf)
1209 {
1210 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1211 
1212 	return sysfs_emit(buf, "%llu\n", btrfs_get_fs_generation(fs_info));
1213 }
1214 BTRFS_ATTR(, generation, btrfs_generation_show);
1215 
1216 static ssize_t btrfs_temp_fsid_show(struct kobject *kobj,
1217 				    struct kobj_attribute *a, char *buf)
1218 {
1219 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1220 
1221 	return sysfs_emit(buf, "%d\n", fs_info->fs_devices->temp_fsid);
1222 }
1223 BTRFS_ATTR(, temp_fsid, btrfs_temp_fsid_show);
1224 
1225 static const char * const btrfs_read_policy_name[] = { "pid" };
1226 
1227 static ssize_t btrfs_read_policy_show(struct kobject *kobj,
1228 				      struct kobj_attribute *a, char *buf)
1229 {
1230 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1231 	const enum btrfs_read_policy policy = READ_ONCE(fs_devices->read_policy);
1232 	ssize_t ret = 0;
1233 	int i;
1234 
1235 	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1236 		if (policy == i)
1237 			ret += sysfs_emit_at(buf, ret, "%s[%s]",
1238 					 (ret == 0 ? "" : " "),
1239 					 btrfs_read_policy_name[i]);
1240 		else
1241 			ret += sysfs_emit_at(buf, ret, "%s%s",
1242 					 (ret == 0 ? "" : " "),
1243 					 btrfs_read_policy_name[i]);
1244 	}
1245 
1246 	ret += sysfs_emit_at(buf, ret, "\n");
1247 
1248 	return ret;
1249 }
1250 
1251 static ssize_t btrfs_read_policy_store(struct kobject *kobj,
1252 				       struct kobj_attribute *a,
1253 				       const char *buf, size_t len)
1254 {
1255 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1256 	int i;
1257 
1258 	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1259 		if (sysfs_streq(buf, btrfs_read_policy_name[i])) {
1260 			if (i != READ_ONCE(fs_devices->read_policy)) {
1261 				WRITE_ONCE(fs_devices->read_policy, i);
1262 				btrfs_info(fs_devices->fs_info,
1263 					   "read policy set to '%s'",
1264 					   btrfs_read_policy_name[i]);
1265 			}
1266 			return len;
1267 		}
1268 	}
1269 
1270 	return -EINVAL;
1271 }
1272 BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store);
1273 
1274 static ssize_t btrfs_bg_reclaim_threshold_show(struct kobject *kobj,
1275 					       struct kobj_attribute *a,
1276 					       char *buf)
1277 {
1278 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1279 
1280 	return sysfs_emit(buf, "%d\n", READ_ONCE(fs_info->bg_reclaim_threshold));
1281 }
1282 
1283 static ssize_t btrfs_bg_reclaim_threshold_store(struct kobject *kobj,
1284 						struct kobj_attribute *a,
1285 						const char *buf, size_t len)
1286 {
1287 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1288 	int thresh;
1289 	int ret;
1290 
1291 	ret = kstrtoint(buf, 10, &thresh);
1292 	if (ret)
1293 		return ret;
1294 
1295 #ifdef CONFIG_BTRFS_DEBUG
1296 	if (thresh != 0 && (thresh > 100))
1297 		return -EINVAL;
1298 #else
1299 	if (thresh != 0 && (thresh <= 50 || thresh > 100))
1300 		return -EINVAL;
1301 #endif
1302 
1303 	WRITE_ONCE(fs_info->bg_reclaim_threshold, thresh);
1304 
1305 	return len;
1306 }
1307 BTRFS_ATTR_RW(, bg_reclaim_threshold, btrfs_bg_reclaim_threshold_show,
1308 	      btrfs_bg_reclaim_threshold_store);
1309 
1310 #ifdef CONFIG_BTRFS_DEBUG
1311 static ssize_t btrfs_offload_csum_show(struct kobject *kobj,
1312 				       struct kobj_attribute *a, char *buf)
1313 {
1314 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1315 
1316 	switch (READ_ONCE(fs_devices->offload_csum_mode)) {
1317 	case BTRFS_OFFLOAD_CSUM_AUTO:
1318 		return sysfs_emit(buf, "auto\n");
1319 	case BTRFS_OFFLOAD_CSUM_FORCE_ON:
1320 		return sysfs_emit(buf, "1\n");
1321 	case BTRFS_OFFLOAD_CSUM_FORCE_OFF:
1322 		return sysfs_emit(buf, "0\n");
1323 	default:
1324 		WARN_ON(1);
1325 		return -EINVAL;
1326 	}
1327 }
1328 
1329 static ssize_t btrfs_offload_csum_store(struct kobject *kobj,
1330 					struct kobj_attribute *a, const char *buf,
1331 					size_t len)
1332 {
1333 	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1334 	int ret;
1335 	bool val;
1336 
1337 	ret = kstrtobool(buf, &val);
1338 	if (ret == 0)
1339 		WRITE_ONCE(fs_devices->offload_csum_mode,
1340 			   val ? BTRFS_OFFLOAD_CSUM_FORCE_ON : BTRFS_OFFLOAD_CSUM_FORCE_OFF);
1341 	else if (ret == -EINVAL && sysfs_streq(buf, "auto"))
1342 		WRITE_ONCE(fs_devices->offload_csum_mode, BTRFS_OFFLOAD_CSUM_AUTO);
1343 	else
1344 		return -EINVAL;
1345 
1346 	return len;
1347 }
1348 BTRFS_ATTR_RW(, offload_csum, btrfs_offload_csum_show, btrfs_offload_csum_store);
1349 #endif
1350 
1351 /*
1352  * Per-filesystem information and stats.
1353  *
1354  * Path: /sys/fs/btrfs/<uuid>/
1355  */
1356 static const struct attribute *btrfs_attrs[] = {
1357 	BTRFS_ATTR_PTR(, label),
1358 	BTRFS_ATTR_PTR(, nodesize),
1359 	BTRFS_ATTR_PTR(, sectorsize),
1360 	BTRFS_ATTR_PTR(, clone_alignment),
1361 	BTRFS_ATTR_PTR(, quota_override),
1362 	BTRFS_ATTR_PTR(, metadata_uuid),
1363 	BTRFS_ATTR_PTR(, checksum),
1364 	BTRFS_ATTR_PTR(, exclusive_operation),
1365 	BTRFS_ATTR_PTR(, generation),
1366 	BTRFS_ATTR_PTR(, read_policy),
1367 	BTRFS_ATTR_PTR(, bg_reclaim_threshold),
1368 	BTRFS_ATTR_PTR(, commit_stats),
1369 	BTRFS_ATTR_PTR(, temp_fsid),
1370 #ifdef CONFIG_BTRFS_DEBUG
1371 	BTRFS_ATTR_PTR(, offload_csum),
1372 #endif
1373 	NULL,
1374 };
1375 
1376 static void btrfs_release_fsid_kobj(struct kobject *kobj)
1377 {
1378 	struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
1379 
1380 	memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
1381 	complete(&fs_devs->kobj_unregister);
1382 }
1383 
1384 static const struct kobj_type btrfs_ktype = {
1385 	.sysfs_ops	= &kobj_sysfs_ops,
1386 	.release	= btrfs_release_fsid_kobj,
1387 };
1388 
1389 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
1390 {
1391 	if (kobj->ktype != &btrfs_ktype)
1392 		return NULL;
1393 	return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
1394 }
1395 
1396 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
1397 {
1398 	if (kobj->ktype != &btrfs_ktype)
1399 		return NULL;
1400 	return to_fs_devs(kobj)->fs_info;
1401 }
1402 
1403 static struct kobject *get_btrfs_kobj(struct kobject *kobj)
1404 {
1405 	while (kobj) {
1406 		if (kobj->ktype == &btrfs_ktype)
1407 			return kobj;
1408 		kobj = kobj->parent;
1409 	}
1410 	return NULL;
1411 }
1412 
1413 #define NUM_FEATURE_BITS 64
1414 #define BTRFS_FEATURE_NAME_MAX 13
1415 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
1416 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
1417 
1418 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names) ==
1419 	      ARRAY_SIZE(btrfs_feature_attrs));
1420 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names[0]) ==
1421 	      ARRAY_SIZE(btrfs_feature_attrs[0]));
1422 
1423 static const u64 supported_feature_masks[FEAT_MAX] = {
1424 	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
1425 	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
1426 	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
1427 };
1428 
1429 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
1430 {
1431 	int set;
1432 
1433 	for (set = 0; set < FEAT_MAX; set++) {
1434 		int i;
1435 		struct attribute *attrs[2];
1436 		struct attribute_group agroup = {
1437 			.name = "features",
1438 			.attrs = attrs,
1439 		};
1440 		u64 features = get_features(fs_info, set);
1441 		features &= ~supported_feature_masks[set];
1442 
1443 		if (!features)
1444 			continue;
1445 
1446 		attrs[1] = NULL;
1447 		for (i = 0; i < NUM_FEATURE_BITS; i++) {
1448 			struct btrfs_feature_attr *fa;
1449 
1450 			if (!(features & (1ULL << i)))
1451 				continue;
1452 
1453 			fa = &btrfs_feature_attrs[set][i];
1454 			attrs[0] = &fa->kobj_attr.attr;
1455 			if (add) {
1456 				int ret;
1457 				ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
1458 							&agroup);
1459 				if (ret)
1460 					return ret;
1461 			} else
1462 				sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
1463 						    &agroup);
1464 		}
1465 
1466 	}
1467 	return 0;
1468 }
1469 
1470 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1471 {
1472 	if (fs_devs->devinfo_kobj) {
1473 		kobject_del(fs_devs->devinfo_kobj);
1474 		kobject_put(fs_devs->devinfo_kobj);
1475 		fs_devs->devinfo_kobj = NULL;
1476 	}
1477 
1478 	if (fs_devs->devices_kobj) {
1479 		kobject_del(fs_devs->devices_kobj);
1480 		kobject_put(fs_devs->devices_kobj);
1481 		fs_devs->devices_kobj = NULL;
1482 	}
1483 
1484 	if (fs_devs->fsid_kobj.state_initialized) {
1485 		kobject_del(&fs_devs->fsid_kobj);
1486 		kobject_put(&fs_devs->fsid_kobj);
1487 		wait_for_completion(&fs_devs->kobj_unregister);
1488 	}
1489 }
1490 
1491 /* when fs_devs is NULL it will remove all fsid kobject */
1492 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1493 {
1494 	struct list_head *fs_uuids = btrfs_get_fs_uuids();
1495 
1496 	if (fs_devs) {
1497 		__btrfs_sysfs_remove_fsid(fs_devs);
1498 		return;
1499 	}
1500 
1501 	list_for_each_entry(fs_devs, fs_uuids, fs_list) {
1502 		__btrfs_sysfs_remove_fsid(fs_devs);
1503 	}
1504 }
1505 
1506 static void btrfs_sysfs_remove_fs_devices(struct btrfs_fs_devices *fs_devices)
1507 {
1508 	struct btrfs_device *device;
1509 	struct btrfs_fs_devices *seed;
1510 
1511 	list_for_each_entry(device, &fs_devices->devices, dev_list)
1512 		btrfs_sysfs_remove_device(device);
1513 
1514 	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1515 		list_for_each_entry(device, &seed->devices, dev_list)
1516 			btrfs_sysfs_remove_device(device);
1517 	}
1518 }
1519 
1520 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
1521 {
1522 	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1523 
1524 	sysfs_remove_link(fsid_kobj, "bdi");
1525 
1526 	if (fs_info->space_info_kobj) {
1527 		sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
1528 		kobject_del(fs_info->space_info_kobj);
1529 		kobject_put(fs_info->space_info_kobj);
1530 	}
1531 	if (fs_info->discard_kobj) {
1532 		sysfs_remove_files(fs_info->discard_kobj, discard_attrs);
1533 		kobject_del(fs_info->discard_kobj);
1534 		kobject_put(fs_info->discard_kobj);
1535 	}
1536 #ifdef CONFIG_BTRFS_DEBUG
1537 	if (fs_info->debug_kobj) {
1538 		sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1539 		kobject_del(fs_info->debug_kobj);
1540 		kobject_put(fs_info->debug_kobj);
1541 	}
1542 #endif
1543 	addrm_unknown_feature_attrs(fs_info, false);
1544 	sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1545 	sysfs_remove_files(fsid_kobj, btrfs_attrs);
1546 	btrfs_sysfs_remove_fs_devices(fs_info->fs_devices);
1547 }
1548 
1549 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
1550 	[FEAT_COMPAT]	 = "compat",
1551 	[FEAT_COMPAT_RO] = "compat_ro",
1552 	[FEAT_INCOMPAT]	 = "incompat",
1553 };
1554 
1555 const char *btrfs_feature_set_name(enum btrfs_feature_set set)
1556 {
1557 	return btrfs_feature_set_names[set];
1558 }
1559 
1560 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
1561 {
1562 	size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
1563 	int len = 0;
1564 	int i;
1565 	char *str;
1566 
1567 	str = kmalloc(bufsize, GFP_KERNEL);
1568 	if (!str)
1569 		return str;
1570 
1571 	for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1572 		const char *name;
1573 
1574 		if (!(flags & (1ULL << i)))
1575 			continue;
1576 
1577 		name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
1578 		len += scnprintf(str + len, bufsize - len, "%s%s",
1579 				len ? "," : "", name);
1580 	}
1581 
1582 	return str;
1583 }
1584 
1585 static void init_feature_attrs(void)
1586 {
1587 	struct btrfs_feature_attr *fa;
1588 	int set, i;
1589 
1590 	memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
1591 	memset(btrfs_unknown_feature_names, 0,
1592 	       sizeof(btrfs_unknown_feature_names));
1593 
1594 	for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
1595 		struct btrfs_feature_attr *sfa;
1596 		struct attribute *a = btrfs_supported_feature_attrs[i];
1597 		int bit;
1598 		sfa = attr_to_btrfs_feature_attr(a);
1599 		bit = ilog2(sfa->feature_bit);
1600 		fa = &btrfs_feature_attrs[sfa->feature_set][bit];
1601 
1602 		fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
1603 	}
1604 
1605 	for (set = 0; set < FEAT_MAX; set++) {
1606 		for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1607 			char *name = btrfs_unknown_feature_names[set][i];
1608 			fa = &btrfs_feature_attrs[set][i];
1609 
1610 			if (fa->kobj_attr.attr.name)
1611 				continue;
1612 
1613 			snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
1614 				 btrfs_feature_set_names[set], i);
1615 
1616 			fa->kobj_attr.attr.name = name;
1617 			fa->kobj_attr.attr.mode = S_IRUGO;
1618 			fa->feature_set = set;
1619 			fa->feature_bit = 1ULL << i;
1620 		}
1621 	}
1622 }
1623 
1624 /*
1625  * Create a sysfs entry for a given block group type at path
1626  * /sys/fs/btrfs/UUID/allocation/data/TYPE
1627  */
1628 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
1629 {
1630 	struct btrfs_fs_info *fs_info = cache->fs_info;
1631 	struct btrfs_space_info *space_info = cache->space_info;
1632 	struct raid_kobject *rkobj;
1633 	const int index = btrfs_bg_flags_to_raid_index(cache->flags);
1634 	unsigned int nofs_flag;
1635 	int ret;
1636 
1637 	/*
1638 	 * Setup a NOFS context because kobject_add(), deep in its call chain,
1639 	 * does GFP_KERNEL allocations, and we are often called in a context
1640 	 * where if reclaim is triggered we can deadlock (we are either holding
1641 	 * a transaction handle or some lock required for a transaction
1642 	 * commit).
1643 	 */
1644 	nofs_flag = memalloc_nofs_save();
1645 
1646 	rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
1647 	if (!rkobj) {
1648 		memalloc_nofs_restore(nofs_flag);
1649 		btrfs_warn(cache->fs_info,
1650 				"couldn't alloc memory for raid level kobject");
1651 		return;
1652 	}
1653 
1654 	rkobj->flags = cache->flags;
1655 	kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
1656 
1657 	/*
1658 	 * We call this either on mount, or if we've created a block group for a
1659 	 * new index type while running (i.e. when restriping).  The running
1660 	 * case is tricky because we could race with other threads, so we need
1661 	 * to have this check to make sure we didn't already init the kobject.
1662 	 *
1663 	 * We don't have to protect on the free side because it only happens on
1664 	 * unmount.
1665 	 */
1666 	spin_lock(&space_info->lock);
1667 	if (space_info->block_group_kobjs[index]) {
1668 		spin_unlock(&space_info->lock);
1669 		kobject_put(&rkobj->kobj);
1670 		return;
1671 	} else {
1672 		space_info->block_group_kobjs[index] = &rkobj->kobj;
1673 	}
1674 	spin_unlock(&space_info->lock);
1675 
1676 	ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
1677 			  btrfs_bg_type_to_raid_name(rkobj->flags));
1678 	memalloc_nofs_restore(nofs_flag);
1679 	if (ret) {
1680 		spin_lock(&space_info->lock);
1681 		space_info->block_group_kobjs[index] = NULL;
1682 		spin_unlock(&space_info->lock);
1683 		kobject_put(&rkobj->kobj);
1684 		btrfs_warn(fs_info,
1685 			"failed to add kobject for block cache, ignoring");
1686 		return;
1687 	}
1688 }
1689 
1690 /*
1691  * Remove sysfs directories for all block group types of a given space info and
1692  * the space info as well
1693  */
1694 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
1695 {
1696 	int i;
1697 
1698 	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1699 		struct kobject *kobj;
1700 
1701 		kobj = space_info->block_group_kobjs[i];
1702 		space_info->block_group_kobjs[i] = NULL;
1703 		if (kobj) {
1704 			kobject_del(kobj);
1705 			kobject_put(kobj);
1706 		}
1707 	}
1708 	kobject_del(&space_info->kobj);
1709 	kobject_put(&space_info->kobj);
1710 }
1711 
1712 static const char *alloc_name(u64 flags)
1713 {
1714 	switch (flags) {
1715 	case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
1716 		return "mixed";
1717 	case BTRFS_BLOCK_GROUP_METADATA:
1718 		return "metadata";
1719 	case BTRFS_BLOCK_GROUP_DATA:
1720 		return "data";
1721 	case BTRFS_BLOCK_GROUP_SYSTEM:
1722 		return "system";
1723 	default:
1724 		WARN_ON(1);
1725 		return "invalid-combination";
1726 	}
1727 }
1728 
1729 /*
1730  * Create a sysfs entry for a space info type at path
1731  * /sys/fs/btrfs/UUID/allocation/TYPE
1732  */
1733 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
1734 				    struct btrfs_space_info *space_info)
1735 {
1736 	int ret;
1737 
1738 	ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
1739 				   fs_info->space_info_kobj, "%s",
1740 				   alloc_name(space_info->flags));
1741 	if (ret) {
1742 		kobject_put(&space_info->kobj);
1743 		return ret;
1744 	}
1745 
1746 	return 0;
1747 }
1748 
1749 void btrfs_sysfs_remove_device(struct btrfs_device *device)
1750 {
1751 	struct kobject *devices_kobj;
1752 
1753 	/*
1754 	 * Seed fs_devices devices_kobj aren't used, fetch kobject from the
1755 	 * fs_info::fs_devices.
1756 	 */
1757 	devices_kobj = device->fs_info->fs_devices->devices_kobj;
1758 	ASSERT(devices_kobj);
1759 
1760 	if (device->bdev)
1761 		sysfs_remove_link(devices_kobj, bdev_kobj(device->bdev)->name);
1762 
1763 	if (device->devid_kobj.state_initialized) {
1764 		kobject_del(&device->devid_kobj);
1765 		kobject_put(&device->devid_kobj);
1766 		wait_for_completion(&device->kobj_unregister);
1767 	}
1768 }
1769 
1770 static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj,
1771 					         struct kobj_attribute *a,
1772 					         char *buf)
1773 {
1774 	int val;
1775 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1776 						   devid_kobj);
1777 
1778 	val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
1779 
1780 	return sysfs_emit(buf, "%d\n", val);
1781 }
1782 BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show);
1783 
1784 static ssize_t btrfs_devinfo_missing_show(struct kobject *kobj,
1785 					struct kobj_attribute *a, char *buf)
1786 {
1787 	int val;
1788 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1789 						   devid_kobj);
1790 
1791 	val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
1792 
1793 	return sysfs_emit(buf, "%d\n", val);
1794 }
1795 BTRFS_ATTR(devid, missing, btrfs_devinfo_missing_show);
1796 
1797 static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj,
1798 					         struct kobj_attribute *a,
1799 					         char *buf)
1800 {
1801 	int val;
1802 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1803 						   devid_kobj);
1804 
1805 	val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
1806 
1807 	return sysfs_emit(buf, "%d\n", val);
1808 }
1809 BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show);
1810 
1811 static ssize_t btrfs_devinfo_scrub_speed_max_show(struct kobject *kobj,
1812 					     struct kobj_attribute *a,
1813 					     char *buf)
1814 {
1815 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1816 						   devid_kobj);
1817 
1818 	return sysfs_emit(buf, "%llu\n", READ_ONCE(device->scrub_speed_max));
1819 }
1820 
1821 static ssize_t btrfs_devinfo_scrub_speed_max_store(struct kobject *kobj,
1822 					      struct kobj_attribute *a,
1823 					      const char *buf, size_t len)
1824 {
1825 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1826 						   devid_kobj);
1827 	char *endptr;
1828 	unsigned long long limit;
1829 
1830 	limit = memparse(buf, &endptr);
1831 	/* There could be trailing '\n', also catch any typos after the value. */
1832 	endptr = skip_spaces(endptr);
1833 	if (*endptr != 0)
1834 		return -EINVAL;
1835 	WRITE_ONCE(device->scrub_speed_max, limit);
1836 	return len;
1837 }
1838 BTRFS_ATTR_RW(devid, scrub_speed_max, btrfs_devinfo_scrub_speed_max_show,
1839 	      btrfs_devinfo_scrub_speed_max_store);
1840 
1841 static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj,
1842 					    struct kobj_attribute *a, char *buf)
1843 {
1844 	int val;
1845 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1846 						   devid_kobj);
1847 
1848 	val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
1849 
1850 	return sysfs_emit(buf, "%d\n", val);
1851 }
1852 BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show);
1853 
1854 static ssize_t btrfs_devinfo_fsid_show(struct kobject *kobj,
1855 				       struct kobj_attribute *a, char *buf)
1856 {
1857 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1858 						   devid_kobj);
1859 
1860 	return sysfs_emit(buf, "%pU\n", device->fs_devices->fsid);
1861 }
1862 BTRFS_ATTR(devid, fsid, btrfs_devinfo_fsid_show);
1863 
1864 static ssize_t btrfs_devinfo_error_stats_show(struct kobject *kobj,
1865 		struct kobj_attribute *a, char *buf)
1866 {
1867 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1868 						   devid_kobj);
1869 
1870 	if (!device->dev_stats_valid)
1871 		return sysfs_emit(buf, "invalid\n");
1872 
1873 	/*
1874 	 * Print all at once so we get a snapshot of all values from the same
1875 	 * time. Keep them in sync and in order of definition of
1876 	 * btrfs_dev_stat_values.
1877 	 */
1878 	return sysfs_emit(buf,
1879 		"write_errs %d\n"
1880 		"read_errs %d\n"
1881 		"flush_errs %d\n"
1882 		"corruption_errs %d\n"
1883 		"generation_errs %d\n",
1884 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_WRITE_ERRS),
1885 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_READ_ERRS),
1886 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_FLUSH_ERRS),
1887 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_CORRUPTION_ERRS),
1888 		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_GENERATION_ERRS));
1889 }
1890 BTRFS_ATTR(devid, error_stats, btrfs_devinfo_error_stats_show);
1891 
1892 /*
1893  * Information about one device.
1894  *
1895  * Path: /sys/fs/btrfs/<uuid>/devinfo/<devid>/
1896  */
1897 static struct attribute *devid_attrs[] = {
1898 	BTRFS_ATTR_PTR(devid, error_stats),
1899 	BTRFS_ATTR_PTR(devid, fsid),
1900 	BTRFS_ATTR_PTR(devid, in_fs_metadata),
1901 	BTRFS_ATTR_PTR(devid, missing),
1902 	BTRFS_ATTR_PTR(devid, replace_target),
1903 	BTRFS_ATTR_PTR(devid, scrub_speed_max),
1904 	BTRFS_ATTR_PTR(devid, writeable),
1905 	NULL
1906 };
1907 ATTRIBUTE_GROUPS(devid);
1908 
1909 static void btrfs_release_devid_kobj(struct kobject *kobj)
1910 {
1911 	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1912 						   devid_kobj);
1913 
1914 	memset(&device->devid_kobj, 0, sizeof(struct kobject));
1915 	complete(&device->kobj_unregister);
1916 }
1917 
1918 static const struct kobj_type devid_ktype = {
1919 	.sysfs_ops	= &kobj_sysfs_ops,
1920 	.default_groups = devid_groups,
1921 	.release	= btrfs_release_devid_kobj,
1922 };
1923 
1924 int btrfs_sysfs_add_device(struct btrfs_device *device)
1925 {
1926 	int ret;
1927 	unsigned int nofs_flag;
1928 	struct kobject *devices_kobj;
1929 	struct kobject *devinfo_kobj;
1930 
1931 	/*
1932 	 * Make sure we use the fs_info::fs_devices to fetch the kobjects even
1933 	 * for the seed fs_devices
1934 	 */
1935 	devices_kobj = device->fs_info->fs_devices->devices_kobj;
1936 	devinfo_kobj = device->fs_info->fs_devices->devinfo_kobj;
1937 	ASSERT(devices_kobj);
1938 	ASSERT(devinfo_kobj);
1939 
1940 	nofs_flag = memalloc_nofs_save();
1941 
1942 	if (device->bdev) {
1943 		struct kobject *disk_kobj = bdev_kobj(device->bdev);
1944 
1945 		ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
1946 		if (ret) {
1947 			btrfs_warn(device->fs_info,
1948 				"creating sysfs device link for devid %llu failed: %d",
1949 				device->devid, ret);
1950 			goto out;
1951 		}
1952 	}
1953 
1954 	init_completion(&device->kobj_unregister);
1955 	ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype,
1956 				   devinfo_kobj, "%llu", device->devid);
1957 	if (ret) {
1958 		kobject_put(&device->devid_kobj);
1959 		btrfs_warn(device->fs_info,
1960 			   "devinfo init for devid %llu failed: %d",
1961 			   device->devid, ret);
1962 	}
1963 
1964 out:
1965 	memalloc_nofs_restore(nofs_flag);
1966 	return ret;
1967 }
1968 
1969 static int btrfs_sysfs_add_fs_devices(struct btrfs_fs_devices *fs_devices)
1970 {
1971 	int ret;
1972 	struct btrfs_device *device;
1973 	struct btrfs_fs_devices *seed;
1974 
1975 	list_for_each_entry(device, &fs_devices->devices, dev_list) {
1976 		ret = btrfs_sysfs_add_device(device);
1977 		if (ret)
1978 			goto fail;
1979 	}
1980 
1981 	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1982 		list_for_each_entry(device, &seed->devices, dev_list) {
1983 			ret = btrfs_sysfs_add_device(device);
1984 			if (ret)
1985 				goto fail;
1986 		}
1987 	}
1988 
1989 	return 0;
1990 
1991 fail:
1992 	btrfs_sysfs_remove_fs_devices(fs_devices);
1993 	return ret;
1994 }
1995 
1996 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1997 {
1998 	int ret;
1999 
2000 	ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
2001 	if (ret)
2002 		pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
2003 			action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
2004 			&disk_to_dev(bdev->bd_disk)->kobj);
2005 }
2006 
2007 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices)
2008 
2009 {
2010 	char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2011 
2012 	/*
2013 	 * Sprouting changes fsid of the mounted filesystem, rename the fsid
2014 	 * directory
2015 	 */
2016 	snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fs_devices->fsid);
2017 	if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
2018 		btrfs_warn(fs_devices->fs_info,
2019 				"sysfs: failed to create fsid for sprout");
2020 }
2021 
2022 void btrfs_sysfs_update_devid(struct btrfs_device *device)
2023 {
2024 	char tmp[24];
2025 
2026 	snprintf(tmp, sizeof(tmp), "%llu", device->devid);
2027 
2028 	if (kobject_rename(&device->devid_kobj, tmp))
2029 		btrfs_warn(device->fs_devices->fs_info,
2030 			   "sysfs: failed to update devid for %llu",
2031 			   device->devid);
2032 }
2033 
2034 /* /sys/fs/btrfs/ entry */
2035 static struct kset *btrfs_kset;
2036 
2037 /*
2038  * Creates:
2039  *		/sys/fs/btrfs/UUID
2040  *
2041  * Can be called by the device discovery thread.
2042  */
2043 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
2044 {
2045 	int error;
2046 
2047 	init_completion(&fs_devs->kobj_unregister);
2048 	fs_devs->fsid_kobj.kset = btrfs_kset;
2049 	error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
2050 				     "%pU", fs_devs->fsid);
2051 	if (error) {
2052 		kobject_put(&fs_devs->fsid_kobj);
2053 		return error;
2054 	}
2055 
2056 	fs_devs->devices_kobj = kobject_create_and_add("devices",
2057 						       &fs_devs->fsid_kobj);
2058 	if (!fs_devs->devices_kobj) {
2059 		btrfs_err(fs_devs->fs_info,
2060 			  "failed to init sysfs device interface");
2061 		btrfs_sysfs_remove_fsid(fs_devs);
2062 		return -ENOMEM;
2063 	}
2064 
2065 	fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
2066 						       &fs_devs->fsid_kobj);
2067 	if (!fs_devs->devinfo_kobj) {
2068 		btrfs_err(fs_devs->fs_info,
2069 			  "failed to init sysfs devinfo kobject");
2070 		btrfs_sysfs_remove_fsid(fs_devs);
2071 		return -ENOMEM;
2072 	}
2073 
2074 	return 0;
2075 }
2076 
2077 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
2078 {
2079 	int error;
2080 	struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
2081 	struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
2082 
2083 	error = btrfs_sysfs_add_fs_devices(fs_devs);
2084 	if (error)
2085 		return error;
2086 
2087 	error = sysfs_create_files(fsid_kobj, btrfs_attrs);
2088 	if (error) {
2089 		btrfs_sysfs_remove_fs_devices(fs_devs);
2090 		return error;
2091 	}
2092 
2093 	error = sysfs_create_group(fsid_kobj,
2094 				   &btrfs_feature_attr_group);
2095 	if (error)
2096 		goto failure;
2097 
2098 #ifdef CONFIG_BTRFS_DEBUG
2099 	fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
2100 	if (!fs_info->debug_kobj) {
2101 		error = -ENOMEM;
2102 		goto failure;
2103 	}
2104 
2105 	error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
2106 	if (error)
2107 		goto failure;
2108 #endif
2109 
2110 	/* Discard directory */
2111 	fs_info->discard_kobj = kobject_create_and_add("discard", fsid_kobj);
2112 	if (!fs_info->discard_kobj) {
2113 		error = -ENOMEM;
2114 		goto failure;
2115 	}
2116 
2117 	error = sysfs_create_files(fs_info->discard_kobj, discard_attrs);
2118 	if (error)
2119 		goto failure;
2120 
2121 	error = addrm_unknown_feature_attrs(fs_info, true);
2122 	if (error)
2123 		goto failure;
2124 
2125 	error = sysfs_create_link(fsid_kobj, &fs_info->sb->s_bdi->dev->kobj, "bdi");
2126 	if (error)
2127 		goto failure;
2128 
2129 	fs_info->space_info_kobj = kobject_create_and_add("allocation",
2130 						  fsid_kobj);
2131 	if (!fs_info->space_info_kobj) {
2132 		error = -ENOMEM;
2133 		goto failure;
2134 	}
2135 
2136 	error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
2137 	if (error)
2138 		goto failure;
2139 
2140 	return 0;
2141 failure:
2142 	btrfs_sysfs_remove_mounted(fs_info);
2143 	return error;
2144 }
2145 
2146 static ssize_t qgroup_enabled_show(struct kobject *qgroups_kobj,
2147 				   struct kobj_attribute *a,
2148 				   char *buf)
2149 {
2150 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2151 	bool enabled;
2152 
2153 	spin_lock(&fs_info->qgroup_lock);
2154 	enabled = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON;
2155 	spin_unlock(&fs_info->qgroup_lock);
2156 
2157 	return sysfs_emit(buf, "%d\n", enabled);
2158 }
2159 BTRFS_ATTR(qgroups, enabled, qgroup_enabled_show);
2160 
2161 static ssize_t qgroup_mode_show(struct kobject *qgroups_kobj,
2162 				struct kobj_attribute *a,
2163 				char *buf)
2164 {
2165 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2166 	ssize_t ret = 0;
2167 
2168 	spin_lock(&fs_info->qgroup_lock);
2169 	ASSERT(btrfs_qgroup_enabled(fs_info));
2170 	switch (btrfs_qgroup_mode(fs_info)) {
2171 	case BTRFS_QGROUP_MODE_FULL:
2172 		ret = sysfs_emit(buf, "qgroup\n");
2173 		break;
2174 	case BTRFS_QGROUP_MODE_SIMPLE:
2175 		ret = sysfs_emit(buf, "squota\n");
2176 		break;
2177 	default:
2178 		btrfs_warn(fs_info, "unexpected qgroup mode %d\n",
2179 			   btrfs_qgroup_mode(fs_info));
2180 		break;
2181 	}
2182 	spin_unlock(&fs_info->qgroup_lock);
2183 
2184 	return ret;
2185 }
2186 BTRFS_ATTR(qgroups, mode, qgroup_mode_show);
2187 
2188 static ssize_t qgroup_inconsistent_show(struct kobject *qgroups_kobj,
2189 					struct kobj_attribute *a,
2190 					char *buf)
2191 {
2192 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2193 	bool inconsistent;
2194 
2195 	spin_lock(&fs_info->qgroup_lock);
2196 	inconsistent = (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT);
2197 	spin_unlock(&fs_info->qgroup_lock);
2198 
2199 	return sysfs_emit(buf, "%d\n", inconsistent);
2200 }
2201 BTRFS_ATTR(qgroups, inconsistent, qgroup_inconsistent_show);
2202 
2203 static ssize_t qgroup_drop_subtree_thres_show(struct kobject *qgroups_kobj,
2204 					      struct kobj_attribute *a,
2205 					      char *buf)
2206 {
2207 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2208 	u8 result;
2209 
2210 	spin_lock(&fs_info->qgroup_lock);
2211 	result = fs_info->qgroup_drop_subtree_thres;
2212 	spin_unlock(&fs_info->qgroup_lock);
2213 
2214 	return sysfs_emit(buf, "%d\n", result);
2215 }
2216 
2217 static ssize_t qgroup_drop_subtree_thres_store(struct kobject *qgroups_kobj,
2218 					       struct kobj_attribute *a,
2219 					       const char *buf, size_t len)
2220 {
2221 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2222 	u8 new_thres;
2223 	int ret;
2224 
2225 	ret = kstrtou8(buf, 10, &new_thres);
2226 	if (ret)
2227 		return -EINVAL;
2228 
2229 	if (new_thres > BTRFS_MAX_LEVEL)
2230 		return -EINVAL;
2231 
2232 	spin_lock(&fs_info->qgroup_lock);
2233 	fs_info->qgroup_drop_subtree_thres = new_thres;
2234 	spin_unlock(&fs_info->qgroup_lock);
2235 
2236 	return len;
2237 }
2238 BTRFS_ATTR_RW(qgroups, drop_subtree_threshold, qgroup_drop_subtree_thres_show,
2239 	      qgroup_drop_subtree_thres_store);
2240 
2241 /*
2242  * Qgroups global info
2243  *
2244  * Path: /sys/fs/btrfs/<uuid>/qgroups/
2245  */
2246 static struct attribute *qgroups_attrs[] = {
2247 	BTRFS_ATTR_PTR(qgroups, enabled),
2248 	BTRFS_ATTR_PTR(qgroups, inconsistent),
2249 	BTRFS_ATTR_PTR(qgroups, drop_subtree_threshold),
2250 	BTRFS_ATTR_PTR(qgroups, mode),
2251 	NULL
2252 };
2253 ATTRIBUTE_GROUPS(qgroups);
2254 
2255 static void qgroups_release(struct kobject *kobj)
2256 {
2257 	kfree(kobj);
2258 }
2259 
2260 static const struct kobj_type qgroups_ktype = {
2261 	.sysfs_ops = &kobj_sysfs_ops,
2262 	.default_groups = qgroups_groups,
2263 	.release = qgroups_release,
2264 };
2265 
2266 static inline struct btrfs_fs_info *qgroup_kobj_to_fs_info(struct kobject *kobj)
2267 {
2268 	return to_fs_info(kobj->parent->parent);
2269 }
2270 
2271 #define QGROUP_ATTR(_member, _show_name)					\
2272 static ssize_t btrfs_qgroup_show_##_member(struct kobject *qgroup_kobj,		\
2273 					   struct kobj_attribute *a,		\
2274 					   char *buf)				\
2275 {										\
2276 	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2277 	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2278 			struct btrfs_qgroup, kobj);				\
2279 	return btrfs_show_u64(&qgroup->_member, &fs_info->qgroup_lock, buf);	\
2280 }										\
2281 BTRFS_ATTR(qgroup, _show_name, btrfs_qgroup_show_##_member)
2282 
2283 #define QGROUP_RSV_ATTR(_name, _type)						\
2284 static ssize_t btrfs_qgroup_rsv_show_##_name(struct kobject *qgroup_kobj,	\
2285 					     struct kobj_attribute *a,		\
2286 					     char *buf)				\
2287 {										\
2288 	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2289 	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2290 			struct btrfs_qgroup, kobj);				\
2291 	return btrfs_show_u64(&qgroup->rsv.values[_type],			\
2292 			&fs_info->qgroup_lock, buf);				\
2293 }										\
2294 BTRFS_ATTR(qgroup, rsv_##_name, btrfs_qgroup_rsv_show_##_name)
2295 
2296 QGROUP_ATTR(rfer, referenced);
2297 QGROUP_ATTR(excl, exclusive);
2298 QGROUP_ATTR(max_rfer, max_referenced);
2299 QGROUP_ATTR(max_excl, max_exclusive);
2300 QGROUP_ATTR(lim_flags, limit_flags);
2301 QGROUP_RSV_ATTR(data, BTRFS_QGROUP_RSV_DATA);
2302 QGROUP_RSV_ATTR(meta_pertrans, BTRFS_QGROUP_RSV_META_PERTRANS);
2303 QGROUP_RSV_ATTR(meta_prealloc, BTRFS_QGROUP_RSV_META_PREALLOC);
2304 
2305 /*
2306  * Qgroup information.
2307  *
2308  * Path: /sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>/
2309  */
2310 static struct attribute *qgroup_attrs[] = {
2311 	BTRFS_ATTR_PTR(qgroup, referenced),
2312 	BTRFS_ATTR_PTR(qgroup, exclusive),
2313 	BTRFS_ATTR_PTR(qgroup, max_referenced),
2314 	BTRFS_ATTR_PTR(qgroup, max_exclusive),
2315 	BTRFS_ATTR_PTR(qgroup, limit_flags),
2316 	BTRFS_ATTR_PTR(qgroup, rsv_data),
2317 	BTRFS_ATTR_PTR(qgroup, rsv_meta_pertrans),
2318 	BTRFS_ATTR_PTR(qgroup, rsv_meta_prealloc),
2319 	NULL
2320 };
2321 ATTRIBUTE_GROUPS(qgroup);
2322 
2323 static void qgroup_release(struct kobject *kobj)
2324 {
2325 	struct btrfs_qgroup *qgroup = container_of(kobj, struct btrfs_qgroup, kobj);
2326 
2327 	memset(&qgroup->kobj, 0, sizeof(*kobj));
2328 }
2329 
2330 static const struct kobj_type qgroup_ktype = {
2331 	.sysfs_ops = &kobj_sysfs_ops,
2332 	.release = qgroup_release,
2333 	.default_groups = qgroup_groups,
2334 };
2335 
2336 int btrfs_sysfs_add_one_qgroup(struct btrfs_fs_info *fs_info,
2337 				struct btrfs_qgroup *qgroup)
2338 {
2339 	struct kobject *qgroups_kobj = fs_info->qgroups_kobj;
2340 	int ret;
2341 
2342 	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2343 		return 0;
2344 	if (qgroup->kobj.state_initialized)
2345 		return 0;
2346 	if (!qgroups_kobj)
2347 		return -EINVAL;
2348 
2349 	ret = kobject_init_and_add(&qgroup->kobj, &qgroup_ktype, qgroups_kobj,
2350 			"%hu_%llu", btrfs_qgroup_level(qgroup->qgroupid),
2351 			btrfs_qgroup_subvolid(qgroup->qgroupid));
2352 	if (ret < 0)
2353 		kobject_put(&qgroup->kobj);
2354 
2355 	return ret;
2356 }
2357 
2358 void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info)
2359 {
2360 	struct btrfs_qgroup *qgroup;
2361 	struct btrfs_qgroup *next;
2362 
2363 	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2364 		return;
2365 
2366 	rbtree_postorder_for_each_entry_safe(qgroup, next,
2367 					     &fs_info->qgroup_tree, node)
2368 		btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
2369 	if (fs_info->qgroups_kobj) {
2370 		kobject_del(fs_info->qgroups_kobj);
2371 		kobject_put(fs_info->qgroups_kobj);
2372 		fs_info->qgroups_kobj = NULL;
2373 	}
2374 }
2375 
2376 /* Called when qgroups get initialized, thus there is no need for locking */
2377 int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info)
2378 {
2379 	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2380 	struct btrfs_qgroup *qgroup;
2381 	struct btrfs_qgroup *next;
2382 	int ret = 0;
2383 
2384 	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2385 		return 0;
2386 
2387 	ASSERT(fsid_kobj);
2388 	if (fs_info->qgroups_kobj)
2389 		return 0;
2390 
2391 	fs_info->qgroups_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
2392 	if (!fs_info->qgroups_kobj)
2393 		return -ENOMEM;
2394 
2395 	ret = kobject_init_and_add(fs_info->qgroups_kobj, &qgroups_ktype,
2396 				   fsid_kobj, "qgroups");
2397 	if (ret < 0)
2398 		goto out;
2399 
2400 	rbtree_postorder_for_each_entry_safe(qgroup, next,
2401 					     &fs_info->qgroup_tree, node) {
2402 		ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
2403 		if (ret < 0)
2404 			goto out;
2405 	}
2406 
2407 out:
2408 	if (ret < 0)
2409 		btrfs_sysfs_del_qgroups(fs_info);
2410 	return ret;
2411 }
2412 
2413 void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
2414 				struct btrfs_qgroup *qgroup)
2415 {
2416 	if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2417 		return;
2418 
2419 	if (qgroup->kobj.state_initialized) {
2420 		kobject_del(&qgroup->kobj);
2421 		kobject_put(&qgroup->kobj);
2422 	}
2423 }
2424 
2425 /*
2426  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
2427  * values in superblock. Call after any changes to incompat/compat_ro flags
2428  */
2429 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info)
2430 {
2431 	struct kobject *fsid_kobj;
2432 	int ret;
2433 
2434 	if (!fs_info)
2435 		return;
2436 
2437 	fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2438 	if (!fsid_kobj->state_initialized)
2439 		return;
2440 
2441 	ret = sysfs_update_group(fsid_kobj, &btrfs_feature_attr_group);
2442 	if (ret < 0)
2443 		btrfs_warn(fs_info,
2444 			   "failed to update /sys/fs/btrfs/%pU/features: %d",
2445 			   fs_info->fs_devices->fsid, ret);
2446 }
2447 
2448 int __init btrfs_init_sysfs(void)
2449 {
2450 	int ret;
2451 
2452 	btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
2453 	if (!btrfs_kset)
2454 		return -ENOMEM;
2455 
2456 	init_feature_attrs();
2457 	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2458 	if (ret)
2459 		goto out2;
2460 	ret = sysfs_merge_group(&btrfs_kset->kobj,
2461 				&btrfs_static_feature_attr_group);
2462 	if (ret)
2463 		goto out_remove_group;
2464 
2465 #ifdef CONFIG_BTRFS_DEBUG
2466 	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2467 	if (ret) {
2468 		sysfs_unmerge_group(&btrfs_kset->kobj,
2469 				    &btrfs_static_feature_attr_group);
2470 		goto out_remove_group;
2471 	}
2472 #endif
2473 
2474 	return 0;
2475 
2476 out_remove_group:
2477 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2478 out2:
2479 	kset_unregister(btrfs_kset);
2480 
2481 	return ret;
2482 }
2483 
2484 void __cold btrfs_exit_sysfs(void)
2485 {
2486 	sysfs_unmerge_group(&btrfs_kset->kobj,
2487 			    &btrfs_static_feature_attr_group);
2488 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2489 #ifdef CONFIG_BTRFS_DEBUG
2490 	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2491 #endif
2492 	kset_unregister(btrfs_kset);
2493 }
2494