xref: /linux/fs/btrfs/sysfs.c (revision 9acb51e9617c28a92f9ce2af767db6bd660a6d4f)
1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   * Copyright (C) 2007 Oracle.  All rights reserved.
4   */
5  
6  #include <linux/sched.h>
7  #include <linux/sched/mm.h>
8  #include <linux/slab.h>
9  #include <linux/spinlock.h>
10  #include <linux/completion.h>
11  #include <linux/bug.h>
12  #include <linux/list.h>
13  #include <crypto/hash.h>
14  #include "messages.h"
15  #include "ctree.h"
16  #include "discard.h"
17  #include "disk-io.h"
18  #include "send.h"
19  #include "transaction.h"
20  #include "sysfs.h"
21  #include "volumes.h"
22  #include "space-info.h"
23  #include "block-group.h"
24  #include "qgroup.h"
25  #include "misc.h"
26  #include "fs.h"
27  #include "accessors.h"
28  
29  /*
30   * Structure name                       Path
31   * --------------------------------------------------------------------------
32   * btrfs_supported_static_feature_attrs /sys/fs/btrfs/features
33   * btrfs_supported_feature_attrs	/sys/fs/btrfs/features and
34   *					/sys/fs/btrfs/<uuid>/features
35   * btrfs_attrs				/sys/fs/btrfs/<uuid>
36   * devid_attrs				/sys/fs/btrfs/<uuid>/devinfo/<devid>
37   * allocation_attrs			/sys/fs/btrfs/<uuid>/allocation
38   * qgroup_attrs				/sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>
39   * space_info_attrs			/sys/fs/btrfs/<uuid>/allocation/<bg-type>
40   * raid_attrs				/sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>
41   * discard_attrs			/sys/fs/btrfs/<uuid>/discard
42   *
43   * When built with BTRFS_CONFIG_DEBUG:
44   *
45   * btrfs_debug_feature_attrs		/sys/fs/btrfs/debug
46   * btrfs_debug_mount_attrs		/sys/fs/btrfs/<uuid>/debug
47   */
48  
49  struct btrfs_feature_attr {
50  	struct kobj_attribute kobj_attr;
51  	enum btrfs_feature_set feature_set;
52  	u64 feature_bit;
53  };
54  
55  /* For raid type sysfs entries */
56  struct raid_kobject {
57  	u64 flags;
58  	struct kobject kobj;
59  };
60  
61  #define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)			\
62  {									\
63  	.attr	= { .name = __stringify(_name), .mode = _mode },	\
64  	.show	= _show,						\
65  	.store	= _store,						\
66  }
67  
68  #define BTRFS_ATTR_W(_prefix, _name, _store)			        \
69  	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
70  			__INIT_KOBJ_ATTR(_name, 0200, NULL, _store)
71  
72  #define BTRFS_ATTR_RW(_prefix, _name, _show, _store)			\
73  	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
74  			__INIT_KOBJ_ATTR(_name, 0644, _show, _store)
75  
76  #define BTRFS_ATTR(_prefix, _name, _show)				\
77  	static struct kobj_attribute btrfs_attr_##_prefix##_##_name =	\
78  			__INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
79  
80  #define BTRFS_ATTR_PTR(_prefix, _name)					\
81  	(&btrfs_attr_##_prefix##_##_name.attr)
82  
83  #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
84  static struct btrfs_feature_attr btrfs_attr_features_##_name = {	     \
85  	.kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,			     \
86  				      btrfs_feature_attr_show,		     \
87  				      btrfs_feature_attr_store),	     \
88  	.feature_set	= _feature_set,					     \
89  	.feature_bit	= _feature_prefix ##_## _feature_bit,		     \
90  }
91  #define BTRFS_FEAT_ATTR_PTR(_name)					     \
92  	(&btrfs_attr_features_##_name.kobj_attr.attr)
93  
94  #define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
95  	BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
96  #define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
97  	BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
98  #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
99  	BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)
100  
101  static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
102  static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
103  static struct kobject *get_btrfs_kobj(struct kobject *kobj);
104  
105  static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
106  {
107  	return container_of(a, struct btrfs_feature_attr, kobj_attr);
108  }
109  
110  static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
111  {
112  	return container_of(attr, struct kobj_attribute, attr);
113  }
114  
115  static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
116  		struct attribute *attr)
117  {
118  	return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
119  }
120  
121  static u64 get_features(struct btrfs_fs_info *fs_info,
122  			enum btrfs_feature_set set)
123  {
124  	struct btrfs_super_block *disk_super = fs_info->super_copy;
125  	if (set == FEAT_COMPAT)
126  		return btrfs_super_compat_flags(disk_super);
127  	else if (set == FEAT_COMPAT_RO)
128  		return btrfs_super_compat_ro_flags(disk_super);
129  	else
130  		return btrfs_super_incompat_flags(disk_super);
131  }
132  
133  static void set_features(struct btrfs_fs_info *fs_info,
134  			 enum btrfs_feature_set set, u64 features)
135  {
136  	struct btrfs_super_block *disk_super = fs_info->super_copy;
137  	if (set == FEAT_COMPAT)
138  		btrfs_set_super_compat_flags(disk_super, features);
139  	else if (set == FEAT_COMPAT_RO)
140  		btrfs_set_super_compat_ro_flags(disk_super, features);
141  	else
142  		btrfs_set_super_incompat_flags(disk_super, features);
143  }
144  
145  static int can_modify_feature(struct btrfs_feature_attr *fa)
146  {
147  	int val = 0;
148  	u64 set, clear;
149  	switch (fa->feature_set) {
150  	case FEAT_COMPAT:
151  		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
152  		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
153  		break;
154  	case FEAT_COMPAT_RO:
155  		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
156  		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
157  		break;
158  	case FEAT_INCOMPAT:
159  		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
160  		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
161  		break;
162  	default:
163  		pr_warn("btrfs: sysfs: unknown feature set %d\n",
164  				fa->feature_set);
165  		return 0;
166  	}
167  
168  	if (set & fa->feature_bit)
169  		val |= 1;
170  	if (clear & fa->feature_bit)
171  		val |= 2;
172  
173  	return val;
174  }
175  
176  static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
177  				       struct kobj_attribute *a, char *buf)
178  {
179  	int val = 0;
180  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
181  	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
182  	if (fs_info) {
183  		u64 features = get_features(fs_info, fa->feature_set);
184  		if (features & fa->feature_bit)
185  			val = 1;
186  	} else
187  		val = can_modify_feature(fa);
188  
189  	return sysfs_emit(buf, "%d\n", val);
190  }
191  
192  static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
193  					struct kobj_attribute *a,
194  					const char *buf, size_t count)
195  {
196  	struct btrfs_fs_info *fs_info;
197  	struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
198  	u64 features, set, clear;
199  	unsigned long val;
200  	int ret;
201  
202  	fs_info = to_fs_info(kobj);
203  	if (!fs_info)
204  		return -EPERM;
205  
206  	if (sb_rdonly(fs_info->sb))
207  		return -EROFS;
208  
209  	ret = kstrtoul(skip_spaces(buf), 0, &val);
210  	if (ret)
211  		return ret;
212  
213  	if (fa->feature_set == FEAT_COMPAT) {
214  		set = BTRFS_FEATURE_COMPAT_SAFE_SET;
215  		clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
216  	} else if (fa->feature_set == FEAT_COMPAT_RO) {
217  		set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
218  		clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
219  	} else {
220  		set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
221  		clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
222  	}
223  
224  	features = get_features(fs_info, fa->feature_set);
225  
226  	/* Nothing to do */
227  	if ((val && (features & fa->feature_bit)) ||
228  	    (!val && !(features & fa->feature_bit)))
229  		return count;
230  
231  	if ((val && !(set & fa->feature_bit)) ||
232  	    (!val && !(clear & fa->feature_bit))) {
233  		btrfs_info(fs_info,
234  			"%sabling feature %s on mounted fs is not supported.",
235  			val ? "En" : "Dis", fa->kobj_attr.attr.name);
236  		return -EPERM;
237  	}
238  
239  	btrfs_info(fs_info, "%s %s feature flag",
240  		   val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
241  
242  	spin_lock(&fs_info->super_lock);
243  	features = get_features(fs_info, fa->feature_set);
244  	if (val)
245  		features |= fa->feature_bit;
246  	else
247  		features &= ~fa->feature_bit;
248  	set_features(fs_info, fa->feature_set, features);
249  	spin_unlock(&fs_info->super_lock);
250  
251  	/*
252  	 * We don't want to do full transaction commit from inside sysfs
253  	 */
254  	set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
255  	wake_up_process(fs_info->transaction_kthread);
256  
257  	return count;
258  }
259  
260  static umode_t btrfs_feature_visible(struct kobject *kobj,
261  				     struct attribute *attr, int unused)
262  {
263  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
264  	umode_t mode = attr->mode;
265  
266  	if (fs_info) {
267  		struct btrfs_feature_attr *fa;
268  		u64 features;
269  
270  		fa = attr_to_btrfs_feature_attr(attr);
271  		features = get_features(fs_info, fa->feature_set);
272  
273  		if (can_modify_feature(fa))
274  			mode |= S_IWUSR;
275  		else if (!(features & fa->feature_bit))
276  			mode = 0;
277  	}
278  
279  	return mode;
280  }
281  
282  BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
283  BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
284  BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
285  BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
286  BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
287  BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
288  BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
289  BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
290  BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
291  BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
292  BTRFS_FEAT_ATTR_COMPAT_RO(block_group_tree, BLOCK_GROUP_TREE);
293  BTRFS_FEAT_ATTR_INCOMPAT(raid1c34, RAID1C34);
294  BTRFS_FEAT_ATTR_INCOMPAT(simple_quota, SIMPLE_QUOTA);
295  #ifdef CONFIG_BLK_DEV_ZONED
296  BTRFS_FEAT_ATTR_INCOMPAT(zoned, ZONED);
297  #endif
298  #ifdef CONFIG_BTRFS_DEBUG
299  /* Remove once support for extent tree v2 is feature complete */
300  BTRFS_FEAT_ATTR_INCOMPAT(extent_tree_v2, EXTENT_TREE_V2);
301  /* Remove once support for raid stripe tree is feature complete. */
302  BTRFS_FEAT_ATTR_INCOMPAT(raid_stripe_tree, RAID_STRIPE_TREE);
303  #endif
304  #ifdef CONFIG_FS_VERITY
305  BTRFS_FEAT_ATTR_COMPAT_RO(verity, VERITY);
306  #endif
307  
308  /*
309   * Features which depend on feature bits and may differ between each fs.
310   *
311   * /sys/fs/btrfs/features      - all available features implemented by this version
312   * /sys/fs/btrfs/UUID/features - features of the fs which are enabled or
313   *                               can be changed on a mounted filesystem.
314   */
315  static struct attribute *btrfs_supported_feature_attrs[] = {
316  	BTRFS_FEAT_ATTR_PTR(default_subvol),
317  	BTRFS_FEAT_ATTR_PTR(mixed_groups),
318  	BTRFS_FEAT_ATTR_PTR(compress_lzo),
319  	BTRFS_FEAT_ATTR_PTR(compress_zstd),
320  	BTRFS_FEAT_ATTR_PTR(extended_iref),
321  	BTRFS_FEAT_ATTR_PTR(raid56),
322  	BTRFS_FEAT_ATTR_PTR(skinny_metadata),
323  	BTRFS_FEAT_ATTR_PTR(no_holes),
324  	BTRFS_FEAT_ATTR_PTR(metadata_uuid),
325  	BTRFS_FEAT_ATTR_PTR(free_space_tree),
326  	BTRFS_FEAT_ATTR_PTR(raid1c34),
327  	BTRFS_FEAT_ATTR_PTR(block_group_tree),
328  	BTRFS_FEAT_ATTR_PTR(simple_quota),
329  #ifdef CONFIG_BLK_DEV_ZONED
330  	BTRFS_FEAT_ATTR_PTR(zoned),
331  #endif
332  #ifdef CONFIG_BTRFS_DEBUG
333  	BTRFS_FEAT_ATTR_PTR(extent_tree_v2),
334  	BTRFS_FEAT_ATTR_PTR(raid_stripe_tree),
335  #endif
336  #ifdef CONFIG_FS_VERITY
337  	BTRFS_FEAT_ATTR_PTR(verity),
338  #endif
339  	NULL
340  };
341  
342  static const struct attribute_group btrfs_feature_attr_group = {
343  	.name = "features",
344  	.is_visible = btrfs_feature_visible,
345  	.attrs = btrfs_supported_feature_attrs,
346  };
347  
348  static ssize_t rmdir_subvol_show(struct kobject *kobj,
349  				 struct kobj_attribute *ka, char *buf)
350  {
351  	return sysfs_emit(buf, "0\n");
352  }
353  BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
354  
355  static ssize_t supported_checksums_show(struct kobject *kobj,
356  					struct kobj_attribute *a, char *buf)
357  {
358  	ssize_t ret = 0;
359  	int i;
360  
361  	for (i = 0; i < btrfs_get_num_csums(); i++) {
362  		/*
363  		 * This "trick" only works as long as 'enum btrfs_csum_type' has
364  		 * no holes in it
365  		 */
366  		ret += sysfs_emit_at(buf, ret, "%s%s", (i == 0 ? "" : " "),
367  				     btrfs_super_csum_name(i));
368  
369  	}
370  
371  	ret += sysfs_emit_at(buf, ret, "\n");
372  	return ret;
373  }
374  BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);
375  
376  static ssize_t send_stream_version_show(struct kobject *kobj,
377  					struct kobj_attribute *ka, char *buf)
378  {
379  	return sysfs_emit(buf, "%d\n", BTRFS_SEND_STREAM_VERSION);
380  }
381  BTRFS_ATTR(static_feature, send_stream_version, send_stream_version_show);
382  
383  static const char *rescue_opts[] = {
384  	"usebackuproot",
385  	"nologreplay",
386  	"ignorebadroots",
387  	"ignoredatacsums",
388  	"ignoremetacsums",
389  	"ignoresuperflags",
390  	"all",
391  };
392  
393  static ssize_t supported_rescue_options_show(struct kobject *kobj,
394  					     struct kobj_attribute *a,
395  					     char *buf)
396  {
397  	ssize_t ret = 0;
398  	int i;
399  
400  	for (i = 0; i < ARRAY_SIZE(rescue_opts); i++)
401  		ret += sysfs_emit_at(buf, ret, "%s%s", (i ? " " : ""), rescue_opts[i]);
402  	ret += sysfs_emit_at(buf, ret, "\n");
403  	return ret;
404  }
405  BTRFS_ATTR(static_feature, supported_rescue_options,
406  	   supported_rescue_options_show);
407  
408  static ssize_t supported_sectorsizes_show(struct kobject *kobj,
409  					  struct kobj_attribute *a,
410  					  char *buf)
411  {
412  	ssize_t ret = 0;
413  
414  	/* An artificial limit to only support 4K and PAGE_SIZE */
415  	if (PAGE_SIZE > SZ_4K)
416  		ret += sysfs_emit_at(buf, ret, "%u ", SZ_4K);
417  	ret += sysfs_emit_at(buf, ret, "%lu\n", PAGE_SIZE);
418  
419  	return ret;
420  }
421  BTRFS_ATTR(static_feature, supported_sectorsizes,
422  	   supported_sectorsizes_show);
423  
424  static ssize_t acl_show(struct kobject *kobj, struct kobj_attribute *a, char *buf)
425  {
426  	return sysfs_emit(buf, "%d\n", IS_ENABLED(CONFIG_BTRFS_FS_POSIX_ACL));
427  }
428  BTRFS_ATTR(static_feature, acl, acl_show);
429  
430  static ssize_t temp_fsid_supported_show(struct kobject *kobj,
431  					struct kobj_attribute *a, char *buf)
432  {
433  	return sysfs_emit(buf, "0\n");
434  }
435  BTRFS_ATTR(static_feature, temp_fsid, temp_fsid_supported_show);
436  
437  /*
438   * Features which only depend on kernel version.
439   *
440   * These are listed in /sys/fs/btrfs/features along with
441   * btrfs_supported_feature_attrs.
442   */
443  static struct attribute *btrfs_supported_static_feature_attrs[] = {
444  	BTRFS_ATTR_PTR(static_feature, acl),
445  	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
446  	BTRFS_ATTR_PTR(static_feature, supported_checksums),
447  	BTRFS_ATTR_PTR(static_feature, send_stream_version),
448  	BTRFS_ATTR_PTR(static_feature, supported_rescue_options),
449  	BTRFS_ATTR_PTR(static_feature, supported_sectorsizes),
450  	BTRFS_ATTR_PTR(static_feature, temp_fsid),
451  	NULL
452  };
453  
454  static const struct attribute_group btrfs_static_feature_attr_group = {
455  	.name = "features",
456  	.attrs = btrfs_supported_static_feature_attrs,
457  };
458  
459  /*
460   * Discard statistics and tunables
461   */
462  #define discard_to_fs_info(_kobj)	to_fs_info(get_btrfs_kobj(_kobj))
463  
464  static ssize_t btrfs_discardable_bytes_show(struct kobject *kobj,
465  					    struct kobj_attribute *a,
466  					    char *buf)
467  {
468  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
469  
470  	return sysfs_emit(buf, "%lld\n",
471  			atomic64_read(&fs_info->discard_ctl.discardable_bytes));
472  }
473  BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
474  
475  static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
476  					      struct kobj_attribute *a,
477  					      char *buf)
478  {
479  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
480  
481  	return sysfs_emit(buf, "%d\n",
482  			atomic_read(&fs_info->discard_ctl.discardable_extents));
483  }
484  BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
485  
486  static ssize_t btrfs_discard_bitmap_bytes_show(struct kobject *kobj,
487  					       struct kobj_attribute *a,
488  					       char *buf)
489  {
490  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
491  
492  	return sysfs_emit(buf, "%llu\n",
493  			  fs_info->discard_ctl.discard_bitmap_bytes);
494  }
495  BTRFS_ATTR(discard, discard_bitmap_bytes, btrfs_discard_bitmap_bytes_show);
496  
497  static ssize_t btrfs_discard_bytes_saved_show(struct kobject *kobj,
498  					      struct kobj_attribute *a,
499  					      char *buf)
500  {
501  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
502  
503  	return sysfs_emit(buf, "%lld\n",
504  		atomic64_read(&fs_info->discard_ctl.discard_bytes_saved));
505  }
506  BTRFS_ATTR(discard, discard_bytes_saved, btrfs_discard_bytes_saved_show);
507  
508  static ssize_t btrfs_discard_extent_bytes_show(struct kobject *kobj,
509  					       struct kobj_attribute *a,
510  					       char *buf)
511  {
512  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
513  
514  	return sysfs_emit(buf, "%llu\n",
515  			  fs_info->discard_ctl.discard_extent_bytes);
516  }
517  BTRFS_ATTR(discard, discard_extent_bytes, btrfs_discard_extent_bytes_show);
518  
519  static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
520  					     struct kobj_attribute *a,
521  					     char *buf)
522  {
523  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
524  
525  	return sysfs_emit(buf, "%u\n",
526  			  READ_ONCE(fs_info->discard_ctl.iops_limit));
527  }
528  
529  static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
530  					      struct kobj_attribute *a,
531  					      const char *buf, size_t len)
532  {
533  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
534  	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
535  	u32 iops_limit;
536  	int ret;
537  
538  	ret = kstrtou32(buf, 10, &iops_limit);
539  	if (ret)
540  		return -EINVAL;
541  
542  	WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
543  	btrfs_discard_calc_delay(discard_ctl);
544  	btrfs_discard_schedule_work(discard_ctl, true);
545  	return len;
546  }
547  BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
548  	      btrfs_discard_iops_limit_store);
549  
550  static ssize_t btrfs_discard_kbps_limit_show(struct kobject *kobj,
551  					     struct kobj_attribute *a,
552  					     char *buf)
553  {
554  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
555  
556  	return sysfs_emit(buf, "%u\n",
557  			  READ_ONCE(fs_info->discard_ctl.kbps_limit));
558  }
559  
560  static ssize_t btrfs_discard_kbps_limit_store(struct kobject *kobj,
561  					      struct kobj_attribute *a,
562  					      const char *buf, size_t len)
563  {
564  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
565  	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
566  	u32 kbps_limit;
567  	int ret;
568  
569  	ret = kstrtou32(buf, 10, &kbps_limit);
570  	if (ret)
571  		return -EINVAL;
572  
573  	WRITE_ONCE(discard_ctl->kbps_limit, kbps_limit);
574  	btrfs_discard_schedule_work(discard_ctl, true);
575  	return len;
576  }
577  BTRFS_ATTR_RW(discard, kbps_limit, btrfs_discard_kbps_limit_show,
578  	      btrfs_discard_kbps_limit_store);
579  
580  static ssize_t btrfs_discard_max_discard_size_show(struct kobject *kobj,
581  						   struct kobj_attribute *a,
582  						   char *buf)
583  {
584  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
585  
586  	return sysfs_emit(buf, "%llu\n",
587  			  READ_ONCE(fs_info->discard_ctl.max_discard_size));
588  }
589  
590  static ssize_t btrfs_discard_max_discard_size_store(struct kobject *kobj,
591  						    struct kobj_attribute *a,
592  						    const char *buf, size_t len)
593  {
594  	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
595  	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
596  	u64 max_discard_size;
597  	int ret;
598  
599  	ret = kstrtou64(buf, 10, &max_discard_size);
600  	if (ret)
601  		return -EINVAL;
602  
603  	WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);
604  
605  	return len;
606  }
607  BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
608  	      btrfs_discard_max_discard_size_store);
609  
610  /*
611   * Per-filesystem stats for discard (when mounted with discard=async).
612   *
613   * Path: /sys/fs/btrfs/<uuid>/discard/
614   */
615  static const struct attribute *discard_attrs[] = {
616  	BTRFS_ATTR_PTR(discard, discardable_bytes),
617  	BTRFS_ATTR_PTR(discard, discardable_extents),
618  	BTRFS_ATTR_PTR(discard, discard_bitmap_bytes),
619  	BTRFS_ATTR_PTR(discard, discard_bytes_saved),
620  	BTRFS_ATTR_PTR(discard, discard_extent_bytes),
621  	BTRFS_ATTR_PTR(discard, iops_limit),
622  	BTRFS_ATTR_PTR(discard, kbps_limit),
623  	BTRFS_ATTR_PTR(discard, max_discard_size),
624  	NULL,
625  };
626  
627  #ifdef CONFIG_BTRFS_DEBUG
628  
629  /*
630   * Per-filesystem runtime debugging exported via sysfs.
631   *
632   * Path: /sys/fs/btrfs/UUID/debug/
633   */
634  static const struct attribute *btrfs_debug_mount_attrs[] = {
635  	NULL,
636  };
637  
638  /*
639   * Runtime debugging exported via sysfs, applies to all mounted filesystems.
640   *
641   * Path: /sys/fs/btrfs/debug
642   */
643  static struct attribute *btrfs_debug_feature_attrs[] = {
644  	NULL
645  };
646  
647  static const struct attribute_group btrfs_debug_feature_attr_group = {
648  	.name = "debug",
649  	.attrs = btrfs_debug_feature_attrs,
650  };
651  
652  #endif
653  
654  static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
655  {
656  	u64 val;
657  	if (lock)
658  		spin_lock(lock);
659  	val = *value_ptr;
660  	if (lock)
661  		spin_unlock(lock);
662  	return sysfs_emit(buf, "%llu\n", val);
663  }
664  
665  static ssize_t global_rsv_size_show(struct kobject *kobj,
666  				    struct kobj_attribute *ka, char *buf)
667  {
668  	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
669  	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
670  	return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
671  }
672  BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
673  
674  static ssize_t global_rsv_reserved_show(struct kobject *kobj,
675  					struct kobj_attribute *a, char *buf)
676  {
677  	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
678  	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
679  	return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
680  }
681  BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
682  
683  #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
684  #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
685  
686  static ssize_t raid_bytes_show(struct kobject *kobj,
687  			       struct kobj_attribute *attr, char *buf);
688  BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
689  BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
690  
691  static ssize_t raid_bytes_show(struct kobject *kobj,
692  			       struct kobj_attribute *attr, char *buf)
693  
694  {
695  	struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
696  	struct btrfs_block_group *block_group;
697  	int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
698  	u64 val = 0;
699  
700  	down_read(&sinfo->groups_sem);
701  	list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
702  		if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
703  			val += block_group->length;
704  		else
705  			val += block_group->used;
706  	}
707  	up_read(&sinfo->groups_sem);
708  	return sysfs_emit(buf, "%llu\n", val);
709  }
710  
711  /*
712   * Allocation information about block group profiles.
713   *
714   * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>/
715   */
716  static struct attribute *raid_attrs[] = {
717  	BTRFS_ATTR_PTR(raid, total_bytes),
718  	BTRFS_ATTR_PTR(raid, used_bytes),
719  	NULL
720  };
721  ATTRIBUTE_GROUPS(raid);
722  
723  static void release_raid_kobj(struct kobject *kobj)
724  {
725  	kfree(to_raid_kobj(kobj));
726  }
727  
728  static const struct kobj_type btrfs_raid_ktype = {
729  	.sysfs_ops = &kobj_sysfs_ops,
730  	.release = release_raid_kobj,
731  	.default_groups = raid_groups,
732  };
733  
734  #define SPACE_INFO_ATTR(field)						\
735  static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,	\
736  					     struct kobj_attribute *a,	\
737  					     char *buf)			\
738  {									\
739  	struct btrfs_space_info *sinfo = to_space_info(kobj);		\
740  	return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);	\
741  }									\
742  BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
743  
744  static ssize_t btrfs_chunk_size_show(struct kobject *kobj,
745  				     struct kobj_attribute *a, char *buf)
746  {
747  	struct btrfs_space_info *sinfo = to_space_info(kobj);
748  
749  	return sysfs_emit(buf, "%llu\n", READ_ONCE(sinfo->chunk_size));
750  }
751  
752  /*
753   * Store new chunk size in space info. Can be called on a read-only filesystem.
754   *
755   * If the new chunk size value is larger than 10% of free space it is reduced
756   * to match that limit. Alignment must be to 256M and the system chunk size
757   * cannot be set.
758   */
759  static ssize_t btrfs_chunk_size_store(struct kobject *kobj,
760  				      struct kobj_attribute *a,
761  				      const char *buf, size_t len)
762  {
763  	struct btrfs_space_info *space_info = to_space_info(kobj);
764  	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
765  	char *retptr;
766  	u64 val;
767  
768  	if (!capable(CAP_SYS_ADMIN))
769  		return -EPERM;
770  
771  	if (!fs_info->fs_devices)
772  		return -EINVAL;
773  
774  	if (btrfs_is_zoned(fs_info))
775  		return -EINVAL;
776  
777  	/* System block type must not be changed. */
778  	if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
779  		return -EPERM;
780  
781  	val = memparse(buf, &retptr);
782  	/* There could be trailing '\n', also catch any typos after the value */
783  	retptr = skip_spaces(retptr);
784  	if (*retptr != 0 || val == 0)
785  		return -EINVAL;
786  
787  	val = min(val, BTRFS_MAX_DATA_CHUNK_SIZE);
788  
789  	/* Limit stripe size to 10% of available space. */
790  	val = min(mult_perc(fs_info->fs_devices->total_rw_bytes, 10), val);
791  
792  	/* Must be multiple of 256M. */
793  	val &= ~((u64)SZ_256M - 1);
794  
795  	/* Must be at least 256M. */
796  	if (val < SZ_256M)
797  		return -EINVAL;
798  
799  	btrfs_update_space_info_chunk_size(space_info, val);
800  
801  	return len;
802  }
803  
804  static ssize_t btrfs_size_classes_show(struct kobject *kobj,
805  				       struct kobj_attribute *a, char *buf)
806  {
807  	struct btrfs_space_info *sinfo = to_space_info(kobj);
808  	struct btrfs_block_group *bg;
809  	u32 none = 0;
810  	u32 small = 0;
811  	u32 medium = 0;
812  	u32 large = 0;
813  
814  	for (int i = 0; i < BTRFS_NR_RAID_TYPES; ++i) {
815  		down_read(&sinfo->groups_sem);
816  		list_for_each_entry(bg, &sinfo->block_groups[i], list) {
817  			if (!btrfs_block_group_should_use_size_class(bg))
818  				continue;
819  			switch (bg->size_class) {
820  			case BTRFS_BG_SZ_NONE:
821  				none++;
822  				break;
823  			case BTRFS_BG_SZ_SMALL:
824  				small++;
825  				break;
826  			case BTRFS_BG_SZ_MEDIUM:
827  				medium++;
828  				break;
829  			case BTRFS_BG_SZ_LARGE:
830  				large++;
831  				break;
832  			}
833  		}
834  		up_read(&sinfo->groups_sem);
835  	}
836  	return sysfs_emit(buf, "none %u\n"
837  			       "small %u\n"
838  			       "medium %u\n"
839  			       "large %u\n",
840  			       none, small, medium, large);
841  }
842  
843  #ifdef CONFIG_BTRFS_DEBUG
844  /*
845   * Request chunk allocation with current chunk size.
846   */
847  static ssize_t btrfs_force_chunk_alloc_store(struct kobject *kobj,
848  					     struct kobj_attribute *a,
849  					     const char *buf, size_t len)
850  {
851  	struct btrfs_space_info *space_info = to_space_info(kobj);
852  	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
853  	struct btrfs_trans_handle *trans;
854  	bool val;
855  	int ret;
856  
857  	if (!capable(CAP_SYS_ADMIN))
858  		return -EPERM;
859  
860  	if (sb_rdonly(fs_info->sb))
861  		return -EROFS;
862  
863  	ret = kstrtobool(buf, &val);
864  	if (ret)
865  		return ret;
866  
867  	if (!val)
868  		return -EINVAL;
869  
870  	/*
871  	 * This is unsafe to be called from sysfs context and may cause
872  	 * unexpected problems.
873  	 */
874  	trans = btrfs_start_transaction(fs_info->tree_root, 0);
875  	if (IS_ERR(trans))
876  		return PTR_ERR(trans);
877  	ret = btrfs_force_chunk_alloc(trans, space_info->flags);
878  	btrfs_end_transaction(trans);
879  
880  	if (ret == 1)
881  		return len;
882  
883  	return -ENOSPC;
884  }
885  BTRFS_ATTR_W(space_info, force_chunk_alloc, btrfs_force_chunk_alloc_store);
886  
887  #endif
888  
889  SPACE_INFO_ATTR(flags);
890  SPACE_INFO_ATTR(total_bytes);
891  SPACE_INFO_ATTR(bytes_used);
892  SPACE_INFO_ATTR(bytes_pinned);
893  SPACE_INFO_ATTR(bytes_reserved);
894  SPACE_INFO_ATTR(bytes_may_use);
895  SPACE_INFO_ATTR(bytes_readonly);
896  SPACE_INFO_ATTR(bytes_zone_unusable);
897  SPACE_INFO_ATTR(disk_used);
898  SPACE_INFO_ATTR(disk_total);
899  SPACE_INFO_ATTR(reclaim_count);
900  SPACE_INFO_ATTR(reclaim_bytes);
901  SPACE_INFO_ATTR(reclaim_errors);
902  BTRFS_ATTR_RW(space_info, chunk_size, btrfs_chunk_size_show, btrfs_chunk_size_store);
903  BTRFS_ATTR(space_info, size_classes, btrfs_size_classes_show);
904  
905  static ssize_t btrfs_sinfo_bg_reclaim_threshold_show(struct kobject *kobj,
906  						     struct kobj_attribute *a,
907  						     char *buf)
908  {
909  	struct btrfs_space_info *space_info = to_space_info(kobj);
910  	ssize_t ret;
911  
912  	spin_lock(&space_info->lock);
913  	ret = sysfs_emit(buf, "%d\n", btrfs_calc_reclaim_threshold(space_info));
914  	spin_unlock(&space_info->lock);
915  	return ret;
916  }
917  
918  static ssize_t btrfs_sinfo_bg_reclaim_threshold_store(struct kobject *kobj,
919  						      struct kobj_attribute *a,
920  						      const char *buf, size_t len)
921  {
922  	struct btrfs_space_info *space_info = to_space_info(kobj);
923  	int thresh;
924  	int ret;
925  
926  	if (READ_ONCE(space_info->dynamic_reclaim))
927  		return -EINVAL;
928  
929  	ret = kstrtoint(buf, 10, &thresh);
930  	if (ret)
931  		return ret;
932  
933  	if (thresh < 0 || thresh > 100)
934  		return -EINVAL;
935  
936  	WRITE_ONCE(space_info->bg_reclaim_threshold, thresh);
937  
938  	return len;
939  }
940  
941  BTRFS_ATTR_RW(space_info, bg_reclaim_threshold,
942  	      btrfs_sinfo_bg_reclaim_threshold_show,
943  	      btrfs_sinfo_bg_reclaim_threshold_store);
944  
945  static ssize_t btrfs_sinfo_dynamic_reclaim_show(struct kobject *kobj,
946  						struct kobj_attribute *a,
947  						char *buf)
948  {
949  	struct btrfs_space_info *space_info = to_space_info(kobj);
950  
951  	return sysfs_emit(buf, "%d\n", READ_ONCE(space_info->dynamic_reclaim));
952  }
953  
954  static ssize_t btrfs_sinfo_dynamic_reclaim_store(struct kobject *kobj,
955  						 struct kobj_attribute *a,
956  						 const char *buf, size_t len)
957  {
958  	struct btrfs_space_info *space_info = to_space_info(kobj);
959  	int dynamic_reclaim;
960  	int ret;
961  
962  	ret = kstrtoint(buf, 10, &dynamic_reclaim);
963  	if (ret)
964  		return ret;
965  
966  	if (dynamic_reclaim < 0)
967  		return -EINVAL;
968  
969  	WRITE_ONCE(space_info->dynamic_reclaim, dynamic_reclaim != 0);
970  
971  	return len;
972  }
973  
974  BTRFS_ATTR_RW(space_info, dynamic_reclaim,
975  	      btrfs_sinfo_dynamic_reclaim_show,
976  	      btrfs_sinfo_dynamic_reclaim_store);
977  
978  static ssize_t btrfs_sinfo_periodic_reclaim_show(struct kobject *kobj,
979  						struct kobj_attribute *a,
980  						char *buf)
981  {
982  	struct btrfs_space_info *space_info = to_space_info(kobj);
983  
984  	return sysfs_emit(buf, "%d\n", READ_ONCE(space_info->periodic_reclaim));
985  }
986  
987  static ssize_t btrfs_sinfo_periodic_reclaim_store(struct kobject *kobj,
988  						 struct kobj_attribute *a,
989  						 const char *buf, size_t len)
990  {
991  	struct btrfs_space_info *space_info = to_space_info(kobj);
992  	int periodic_reclaim;
993  	int ret;
994  
995  	ret = kstrtoint(buf, 10, &periodic_reclaim);
996  	if (ret)
997  		return ret;
998  
999  	if (periodic_reclaim < 0)
1000  		return -EINVAL;
1001  
1002  	WRITE_ONCE(space_info->periodic_reclaim, periodic_reclaim != 0);
1003  
1004  	return len;
1005  }
1006  
1007  BTRFS_ATTR_RW(space_info, periodic_reclaim,
1008  	      btrfs_sinfo_periodic_reclaim_show,
1009  	      btrfs_sinfo_periodic_reclaim_store);
1010  
1011  /*
1012   * Allocation information about block group types.
1013   *
1014   * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/
1015   */
1016  static struct attribute *space_info_attrs[] = {
1017  	BTRFS_ATTR_PTR(space_info, flags),
1018  	BTRFS_ATTR_PTR(space_info, total_bytes),
1019  	BTRFS_ATTR_PTR(space_info, bytes_used),
1020  	BTRFS_ATTR_PTR(space_info, bytes_pinned),
1021  	BTRFS_ATTR_PTR(space_info, bytes_reserved),
1022  	BTRFS_ATTR_PTR(space_info, bytes_may_use),
1023  	BTRFS_ATTR_PTR(space_info, bytes_readonly),
1024  	BTRFS_ATTR_PTR(space_info, bytes_zone_unusable),
1025  	BTRFS_ATTR_PTR(space_info, disk_used),
1026  	BTRFS_ATTR_PTR(space_info, disk_total),
1027  	BTRFS_ATTR_PTR(space_info, bg_reclaim_threshold),
1028  	BTRFS_ATTR_PTR(space_info, dynamic_reclaim),
1029  	BTRFS_ATTR_PTR(space_info, chunk_size),
1030  	BTRFS_ATTR_PTR(space_info, size_classes),
1031  	BTRFS_ATTR_PTR(space_info, reclaim_count),
1032  	BTRFS_ATTR_PTR(space_info, reclaim_bytes),
1033  	BTRFS_ATTR_PTR(space_info, reclaim_errors),
1034  	BTRFS_ATTR_PTR(space_info, periodic_reclaim),
1035  #ifdef CONFIG_BTRFS_DEBUG
1036  	BTRFS_ATTR_PTR(space_info, force_chunk_alloc),
1037  #endif
1038  	NULL,
1039  };
1040  ATTRIBUTE_GROUPS(space_info);
1041  
1042  static void space_info_release(struct kobject *kobj)
1043  {
1044  	struct btrfs_space_info *sinfo = to_space_info(kobj);
1045  	kfree(sinfo);
1046  }
1047  
1048  static const struct kobj_type space_info_ktype = {
1049  	.sysfs_ops = &kobj_sysfs_ops,
1050  	.release = space_info_release,
1051  	.default_groups = space_info_groups,
1052  };
1053  
1054  /*
1055   * Allocation information about block groups.
1056   *
1057   * Path: /sys/fs/btrfs/<uuid>/allocation/
1058   */
1059  static const struct attribute *allocation_attrs[] = {
1060  	BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
1061  	BTRFS_ATTR_PTR(allocation, global_rsv_size),
1062  	NULL,
1063  };
1064  
1065  static ssize_t btrfs_label_show(struct kobject *kobj,
1066  				struct kobj_attribute *a, char *buf)
1067  {
1068  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1069  	char *label = fs_info->super_copy->label;
1070  	ssize_t ret;
1071  
1072  	spin_lock(&fs_info->super_lock);
1073  	ret = sysfs_emit(buf, label[0] ? "%s\n" : "%s", label);
1074  	spin_unlock(&fs_info->super_lock);
1075  
1076  	return ret;
1077  }
1078  
1079  static ssize_t btrfs_label_store(struct kobject *kobj,
1080  				 struct kobj_attribute *a,
1081  				 const char *buf, size_t len)
1082  {
1083  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1084  	size_t p_len;
1085  
1086  	if (!fs_info)
1087  		return -EPERM;
1088  
1089  	if (sb_rdonly(fs_info->sb))
1090  		return -EROFS;
1091  
1092  	/*
1093  	 * p_len is the len until the first occurrence of either
1094  	 * '\n' or '\0'
1095  	 */
1096  	p_len = strcspn(buf, "\n");
1097  
1098  	if (p_len >= BTRFS_LABEL_SIZE)
1099  		return -EINVAL;
1100  
1101  	spin_lock(&fs_info->super_lock);
1102  	memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
1103  	memcpy(fs_info->super_copy->label, buf, p_len);
1104  	spin_unlock(&fs_info->super_lock);
1105  
1106  	/*
1107  	 * We don't want to do full transaction commit from inside sysfs
1108  	 */
1109  	set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
1110  	wake_up_process(fs_info->transaction_kthread);
1111  
1112  	return len;
1113  }
1114  BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
1115  
1116  static ssize_t btrfs_nodesize_show(struct kobject *kobj,
1117  				struct kobj_attribute *a, char *buf)
1118  {
1119  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1120  
1121  	return sysfs_emit(buf, "%u\n", fs_info->super_copy->nodesize);
1122  }
1123  
1124  BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
1125  
1126  static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
1127  				struct kobj_attribute *a, char *buf)
1128  {
1129  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1130  
1131  	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
1132  }
1133  
1134  BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
1135  
1136  static ssize_t btrfs_commit_stats_show(struct kobject *kobj,
1137  				       struct kobj_attribute *a, char *buf)
1138  {
1139  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1140  
1141  	return sysfs_emit(buf,
1142  		"commits %llu\n"
1143  		"last_commit_ms %llu\n"
1144  		"max_commit_ms %llu\n"
1145  		"total_commit_ms %llu\n",
1146  		fs_info->commit_stats.commit_count,
1147  		div_u64(fs_info->commit_stats.last_commit_dur, NSEC_PER_MSEC),
1148  		div_u64(fs_info->commit_stats.max_commit_dur, NSEC_PER_MSEC),
1149  		div_u64(fs_info->commit_stats.total_commit_dur, NSEC_PER_MSEC));
1150  }
1151  
1152  static ssize_t btrfs_commit_stats_store(struct kobject *kobj,
1153  					struct kobj_attribute *a,
1154  					const char *buf, size_t len)
1155  {
1156  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1157  	unsigned long val;
1158  	int ret;
1159  
1160  	if (!fs_info)
1161  		return -EPERM;
1162  
1163  	if (!capable(CAP_SYS_RESOURCE))
1164  		return -EPERM;
1165  
1166  	ret = kstrtoul(buf, 10, &val);
1167  	if (ret)
1168  		return ret;
1169  	if (val)
1170  		return -EINVAL;
1171  
1172  	WRITE_ONCE(fs_info->commit_stats.max_commit_dur, 0);
1173  
1174  	return len;
1175  }
1176  BTRFS_ATTR_RW(, commit_stats, btrfs_commit_stats_show, btrfs_commit_stats_store);
1177  
1178  static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
1179  				struct kobj_attribute *a, char *buf)
1180  {
1181  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1182  
1183  	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
1184  }
1185  
1186  BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
1187  
1188  static ssize_t quota_override_show(struct kobject *kobj,
1189  				   struct kobj_attribute *a, char *buf)
1190  {
1191  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1192  	int quota_override;
1193  
1194  	quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1195  	return sysfs_emit(buf, "%d\n", quota_override);
1196  }
1197  
1198  static ssize_t quota_override_store(struct kobject *kobj,
1199  				    struct kobj_attribute *a,
1200  				    const char *buf, size_t len)
1201  {
1202  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1203  	unsigned long knob;
1204  	int err;
1205  
1206  	if (!fs_info)
1207  		return -EPERM;
1208  
1209  	if (!capable(CAP_SYS_RESOURCE))
1210  		return -EPERM;
1211  
1212  	err = kstrtoul(buf, 10, &knob);
1213  	if (err)
1214  		return err;
1215  	if (knob > 1)
1216  		return -EINVAL;
1217  
1218  	if (knob)
1219  		set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1220  	else
1221  		clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1222  
1223  	return len;
1224  }
1225  
1226  BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
1227  
1228  static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
1229  				struct kobj_attribute *a, char *buf)
1230  {
1231  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1232  
1233  	return sysfs_emit(buf, "%pU\n", fs_info->fs_devices->metadata_uuid);
1234  }
1235  
1236  BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
1237  
1238  static ssize_t btrfs_checksum_show(struct kobject *kobj,
1239  				   struct kobj_attribute *a, char *buf)
1240  {
1241  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1242  	u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
1243  
1244  	return sysfs_emit(buf, "%s (%s)\n",
1245  			  btrfs_super_csum_name(csum_type),
1246  			  crypto_shash_driver_name(fs_info->csum_shash));
1247  }
1248  
1249  BTRFS_ATTR(, checksum, btrfs_checksum_show);
1250  
1251  static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
1252  		struct kobj_attribute *a, char *buf)
1253  {
1254  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1255  	const char *str;
1256  
1257  	switch (READ_ONCE(fs_info->exclusive_operation)) {
1258  		case  BTRFS_EXCLOP_NONE:
1259  			str = "none\n";
1260  			break;
1261  		case BTRFS_EXCLOP_BALANCE:
1262  			str = "balance\n";
1263  			break;
1264  		case BTRFS_EXCLOP_BALANCE_PAUSED:
1265  			str = "balance paused\n";
1266  			break;
1267  		case BTRFS_EXCLOP_DEV_ADD:
1268  			str = "device add\n";
1269  			break;
1270  		case BTRFS_EXCLOP_DEV_REMOVE:
1271  			str = "device remove\n";
1272  			break;
1273  		case BTRFS_EXCLOP_DEV_REPLACE:
1274  			str = "device replace\n";
1275  			break;
1276  		case BTRFS_EXCLOP_RESIZE:
1277  			str = "resize\n";
1278  			break;
1279  		case BTRFS_EXCLOP_SWAP_ACTIVATE:
1280  			str = "swap activate\n";
1281  			break;
1282  		default:
1283  			str = "UNKNOWN\n";
1284  			break;
1285  	}
1286  	return sysfs_emit(buf, "%s", str);
1287  }
1288  BTRFS_ATTR(, exclusive_operation, btrfs_exclusive_operation_show);
1289  
1290  static ssize_t btrfs_generation_show(struct kobject *kobj,
1291  				     struct kobj_attribute *a, char *buf)
1292  {
1293  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1294  
1295  	return sysfs_emit(buf, "%llu\n", btrfs_get_fs_generation(fs_info));
1296  }
1297  BTRFS_ATTR(, generation, btrfs_generation_show);
1298  
1299  static ssize_t btrfs_temp_fsid_show(struct kobject *kobj,
1300  				    struct kobj_attribute *a, char *buf)
1301  {
1302  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1303  
1304  	return sysfs_emit(buf, "%d\n", fs_info->fs_devices->temp_fsid);
1305  }
1306  BTRFS_ATTR(, temp_fsid, btrfs_temp_fsid_show);
1307  
1308  static const char * const btrfs_read_policy_name[] = { "pid" };
1309  
1310  static ssize_t btrfs_read_policy_show(struct kobject *kobj,
1311  				      struct kobj_attribute *a, char *buf)
1312  {
1313  	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1314  	const enum btrfs_read_policy policy = READ_ONCE(fs_devices->read_policy);
1315  	ssize_t ret = 0;
1316  	int i;
1317  
1318  	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1319  		if (policy == i)
1320  			ret += sysfs_emit_at(buf, ret, "%s[%s]",
1321  					 (ret == 0 ? "" : " "),
1322  					 btrfs_read_policy_name[i]);
1323  		else
1324  			ret += sysfs_emit_at(buf, ret, "%s%s",
1325  					 (ret == 0 ? "" : " "),
1326  					 btrfs_read_policy_name[i]);
1327  	}
1328  
1329  	ret += sysfs_emit_at(buf, ret, "\n");
1330  
1331  	return ret;
1332  }
1333  
1334  static ssize_t btrfs_read_policy_store(struct kobject *kobj,
1335  				       struct kobj_attribute *a,
1336  				       const char *buf, size_t len)
1337  {
1338  	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1339  	int i;
1340  
1341  	for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1342  		if (sysfs_streq(buf, btrfs_read_policy_name[i])) {
1343  			if (i != READ_ONCE(fs_devices->read_policy)) {
1344  				WRITE_ONCE(fs_devices->read_policy, i);
1345  				btrfs_info(fs_devices->fs_info,
1346  					   "read policy set to '%s'",
1347  					   btrfs_read_policy_name[i]);
1348  			}
1349  			return len;
1350  		}
1351  	}
1352  
1353  	return -EINVAL;
1354  }
1355  BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store);
1356  
1357  static ssize_t btrfs_bg_reclaim_threshold_show(struct kobject *kobj,
1358  					       struct kobj_attribute *a,
1359  					       char *buf)
1360  {
1361  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1362  
1363  	return sysfs_emit(buf, "%d\n", READ_ONCE(fs_info->bg_reclaim_threshold));
1364  }
1365  
1366  static ssize_t btrfs_bg_reclaim_threshold_store(struct kobject *kobj,
1367  						struct kobj_attribute *a,
1368  						const char *buf, size_t len)
1369  {
1370  	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1371  	int thresh;
1372  	int ret;
1373  
1374  	ret = kstrtoint(buf, 10, &thresh);
1375  	if (ret)
1376  		return ret;
1377  
1378  #ifdef CONFIG_BTRFS_DEBUG
1379  	if (thresh != 0 && (thresh > 100))
1380  		return -EINVAL;
1381  #else
1382  	if (thresh != 0 && (thresh <= 50 || thresh > 100))
1383  		return -EINVAL;
1384  #endif
1385  
1386  	WRITE_ONCE(fs_info->bg_reclaim_threshold, thresh);
1387  
1388  	return len;
1389  }
1390  BTRFS_ATTR_RW(, bg_reclaim_threshold, btrfs_bg_reclaim_threshold_show,
1391  	      btrfs_bg_reclaim_threshold_store);
1392  
1393  #ifdef CONFIG_BTRFS_DEBUG
1394  static ssize_t btrfs_offload_csum_show(struct kobject *kobj,
1395  				       struct kobj_attribute *a, char *buf)
1396  {
1397  	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1398  
1399  	switch (READ_ONCE(fs_devices->offload_csum_mode)) {
1400  	case BTRFS_OFFLOAD_CSUM_AUTO:
1401  		return sysfs_emit(buf, "auto\n");
1402  	case BTRFS_OFFLOAD_CSUM_FORCE_ON:
1403  		return sysfs_emit(buf, "1\n");
1404  	case BTRFS_OFFLOAD_CSUM_FORCE_OFF:
1405  		return sysfs_emit(buf, "0\n");
1406  	default:
1407  		WARN_ON(1);
1408  		return -EINVAL;
1409  	}
1410  }
1411  
1412  static ssize_t btrfs_offload_csum_store(struct kobject *kobj,
1413  					struct kobj_attribute *a, const char *buf,
1414  					size_t len)
1415  {
1416  	struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1417  	int ret;
1418  	bool val;
1419  
1420  	ret = kstrtobool(buf, &val);
1421  	if (ret == 0)
1422  		WRITE_ONCE(fs_devices->offload_csum_mode,
1423  			   val ? BTRFS_OFFLOAD_CSUM_FORCE_ON : BTRFS_OFFLOAD_CSUM_FORCE_OFF);
1424  	else if (ret == -EINVAL && sysfs_streq(buf, "auto"))
1425  		WRITE_ONCE(fs_devices->offload_csum_mode, BTRFS_OFFLOAD_CSUM_AUTO);
1426  	else
1427  		return -EINVAL;
1428  
1429  	return len;
1430  }
1431  BTRFS_ATTR_RW(, offload_csum, btrfs_offload_csum_show, btrfs_offload_csum_store);
1432  #endif
1433  
1434  /*
1435   * Per-filesystem information and stats.
1436   *
1437   * Path: /sys/fs/btrfs/<uuid>/
1438   */
1439  static const struct attribute *btrfs_attrs[] = {
1440  	BTRFS_ATTR_PTR(, label),
1441  	BTRFS_ATTR_PTR(, nodesize),
1442  	BTRFS_ATTR_PTR(, sectorsize),
1443  	BTRFS_ATTR_PTR(, clone_alignment),
1444  	BTRFS_ATTR_PTR(, quota_override),
1445  	BTRFS_ATTR_PTR(, metadata_uuid),
1446  	BTRFS_ATTR_PTR(, checksum),
1447  	BTRFS_ATTR_PTR(, exclusive_operation),
1448  	BTRFS_ATTR_PTR(, generation),
1449  	BTRFS_ATTR_PTR(, read_policy),
1450  	BTRFS_ATTR_PTR(, bg_reclaim_threshold),
1451  	BTRFS_ATTR_PTR(, commit_stats),
1452  	BTRFS_ATTR_PTR(, temp_fsid),
1453  #ifdef CONFIG_BTRFS_DEBUG
1454  	BTRFS_ATTR_PTR(, offload_csum),
1455  #endif
1456  	NULL,
1457  };
1458  
1459  static void btrfs_release_fsid_kobj(struct kobject *kobj)
1460  {
1461  	struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
1462  
1463  	memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
1464  	complete(&fs_devs->kobj_unregister);
1465  }
1466  
1467  static const struct kobj_type btrfs_ktype = {
1468  	.sysfs_ops	= &kobj_sysfs_ops,
1469  	.release	= btrfs_release_fsid_kobj,
1470  };
1471  
1472  static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
1473  {
1474  	if (kobj->ktype != &btrfs_ktype)
1475  		return NULL;
1476  	return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
1477  }
1478  
1479  static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
1480  {
1481  	if (kobj->ktype != &btrfs_ktype)
1482  		return NULL;
1483  	return to_fs_devs(kobj)->fs_info;
1484  }
1485  
1486  static struct kobject *get_btrfs_kobj(struct kobject *kobj)
1487  {
1488  	while (kobj) {
1489  		if (kobj->ktype == &btrfs_ktype)
1490  			return kobj;
1491  		kobj = kobj->parent;
1492  	}
1493  	return NULL;
1494  }
1495  
1496  #define NUM_FEATURE_BITS 64
1497  #define BTRFS_FEATURE_NAME_MAX 13
1498  static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
1499  static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
1500  
1501  static_assert(ARRAY_SIZE(btrfs_unknown_feature_names) ==
1502  	      ARRAY_SIZE(btrfs_feature_attrs));
1503  static_assert(ARRAY_SIZE(btrfs_unknown_feature_names[0]) ==
1504  	      ARRAY_SIZE(btrfs_feature_attrs[0]));
1505  
1506  static const u64 supported_feature_masks[FEAT_MAX] = {
1507  	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
1508  	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
1509  	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
1510  };
1511  
1512  static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
1513  {
1514  	int set;
1515  
1516  	for (set = 0; set < FEAT_MAX; set++) {
1517  		int i;
1518  		struct attribute *attrs[2];
1519  		struct attribute_group agroup = {
1520  			.name = "features",
1521  			.attrs = attrs,
1522  		};
1523  		u64 features = get_features(fs_info, set);
1524  		features &= ~supported_feature_masks[set];
1525  
1526  		if (!features)
1527  			continue;
1528  
1529  		attrs[1] = NULL;
1530  		for (i = 0; i < NUM_FEATURE_BITS; i++) {
1531  			struct btrfs_feature_attr *fa;
1532  
1533  			if (!(features & (1ULL << i)))
1534  				continue;
1535  
1536  			fa = &btrfs_feature_attrs[set][i];
1537  			attrs[0] = &fa->kobj_attr.attr;
1538  			if (add) {
1539  				int ret;
1540  				ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
1541  							&agroup);
1542  				if (ret)
1543  					return ret;
1544  			} else
1545  				sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
1546  						    &agroup);
1547  		}
1548  
1549  	}
1550  	return 0;
1551  }
1552  
1553  static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1554  {
1555  	if (fs_devs->devinfo_kobj) {
1556  		kobject_del(fs_devs->devinfo_kobj);
1557  		kobject_put(fs_devs->devinfo_kobj);
1558  		fs_devs->devinfo_kobj = NULL;
1559  	}
1560  
1561  	if (fs_devs->devices_kobj) {
1562  		kobject_del(fs_devs->devices_kobj);
1563  		kobject_put(fs_devs->devices_kobj);
1564  		fs_devs->devices_kobj = NULL;
1565  	}
1566  
1567  	if (fs_devs->fsid_kobj.state_initialized) {
1568  		kobject_del(&fs_devs->fsid_kobj);
1569  		kobject_put(&fs_devs->fsid_kobj);
1570  		wait_for_completion(&fs_devs->kobj_unregister);
1571  	}
1572  }
1573  
1574  /* when fs_devs is NULL it will remove all fsid kobject */
1575  void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1576  {
1577  	struct list_head *fs_uuids = btrfs_get_fs_uuids();
1578  
1579  	if (fs_devs) {
1580  		__btrfs_sysfs_remove_fsid(fs_devs);
1581  		return;
1582  	}
1583  
1584  	list_for_each_entry(fs_devs, fs_uuids, fs_list) {
1585  		__btrfs_sysfs_remove_fsid(fs_devs);
1586  	}
1587  }
1588  
1589  static void btrfs_sysfs_remove_fs_devices(struct btrfs_fs_devices *fs_devices)
1590  {
1591  	struct btrfs_device *device;
1592  	struct btrfs_fs_devices *seed;
1593  
1594  	list_for_each_entry(device, &fs_devices->devices, dev_list)
1595  		btrfs_sysfs_remove_device(device);
1596  
1597  	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1598  		list_for_each_entry(device, &seed->devices, dev_list)
1599  			btrfs_sysfs_remove_device(device);
1600  	}
1601  }
1602  
1603  void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
1604  {
1605  	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1606  
1607  	sysfs_remove_link(fsid_kobj, "bdi");
1608  
1609  	if (fs_info->space_info_kobj) {
1610  		sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
1611  		kobject_del(fs_info->space_info_kobj);
1612  		kobject_put(fs_info->space_info_kobj);
1613  	}
1614  	if (fs_info->discard_kobj) {
1615  		sysfs_remove_files(fs_info->discard_kobj, discard_attrs);
1616  		kobject_del(fs_info->discard_kobj);
1617  		kobject_put(fs_info->discard_kobj);
1618  	}
1619  #ifdef CONFIG_BTRFS_DEBUG
1620  	if (fs_info->debug_kobj) {
1621  		sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1622  		kobject_del(fs_info->debug_kobj);
1623  		kobject_put(fs_info->debug_kobj);
1624  	}
1625  #endif
1626  	addrm_unknown_feature_attrs(fs_info, false);
1627  	sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1628  	sysfs_remove_files(fsid_kobj, btrfs_attrs);
1629  	btrfs_sysfs_remove_fs_devices(fs_info->fs_devices);
1630  }
1631  
1632  static const char * const btrfs_feature_set_names[FEAT_MAX] = {
1633  	[FEAT_COMPAT]	 = "compat",
1634  	[FEAT_COMPAT_RO] = "compat_ro",
1635  	[FEAT_INCOMPAT]	 = "incompat",
1636  };
1637  
1638  const char *btrfs_feature_set_name(enum btrfs_feature_set set)
1639  {
1640  	return btrfs_feature_set_names[set];
1641  }
1642  
1643  char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
1644  {
1645  	size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
1646  	int len = 0;
1647  	int i;
1648  	char *str;
1649  
1650  	str = kmalloc(bufsize, GFP_KERNEL);
1651  	if (!str)
1652  		return str;
1653  
1654  	for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1655  		const char *name;
1656  
1657  		if (!(flags & (1ULL << i)))
1658  			continue;
1659  
1660  		name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
1661  		len += scnprintf(str + len, bufsize - len, "%s%s",
1662  				len ? "," : "", name);
1663  	}
1664  
1665  	return str;
1666  }
1667  
1668  static void init_feature_attrs(void)
1669  {
1670  	struct btrfs_feature_attr *fa;
1671  	int set, i;
1672  
1673  	memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
1674  	memset(btrfs_unknown_feature_names, 0,
1675  	       sizeof(btrfs_unknown_feature_names));
1676  
1677  	for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
1678  		struct btrfs_feature_attr *sfa;
1679  		struct attribute *a = btrfs_supported_feature_attrs[i];
1680  		int bit;
1681  		sfa = attr_to_btrfs_feature_attr(a);
1682  		bit = ilog2(sfa->feature_bit);
1683  		fa = &btrfs_feature_attrs[sfa->feature_set][bit];
1684  
1685  		fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
1686  	}
1687  
1688  	for (set = 0; set < FEAT_MAX; set++) {
1689  		for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1690  			char *name = btrfs_unknown_feature_names[set][i];
1691  			fa = &btrfs_feature_attrs[set][i];
1692  
1693  			if (fa->kobj_attr.attr.name)
1694  				continue;
1695  
1696  			snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
1697  				 btrfs_feature_set_names[set], i);
1698  
1699  			fa->kobj_attr.attr.name = name;
1700  			fa->kobj_attr.attr.mode = S_IRUGO;
1701  			fa->feature_set = set;
1702  			fa->feature_bit = 1ULL << i;
1703  		}
1704  	}
1705  }
1706  
1707  /*
1708   * Create a sysfs entry for a given block group type at path
1709   * /sys/fs/btrfs/UUID/allocation/data/TYPE
1710   */
1711  void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
1712  {
1713  	struct btrfs_fs_info *fs_info = cache->fs_info;
1714  	struct btrfs_space_info *space_info = cache->space_info;
1715  	struct raid_kobject *rkobj;
1716  	const int index = btrfs_bg_flags_to_raid_index(cache->flags);
1717  	unsigned int nofs_flag;
1718  	int ret;
1719  
1720  	/*
1721  	 * Setup a NOFS context because kobject_add(), deep in its call chain,
1722  	 * does GFP_KERNEL allocations, and we are often called in a context
1723  	 * where if reclaim is triggered we can deadlock (we are either holding
1724  	 * a transaction handle or some lock required for a transaction
1725  	 * commit).
1726  	 */
1727  	nofs_flag = memalloc_nofs_save();
1728  
1729  	rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
1730  	if (!rkobj) {
1731  		memalloc_nofs_restore(nofs_flag);
1732  		btrfs_warn(cache->fs_info,
1733  				"couldn't alloc memory for raid level kobject");
1734  		return;
1735  	}
1736  
1737  	rkobj->flags = cache->flags;
1738  	kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
1739  
1740  	/*
1741  	 * We call this either on mount, or if we've created a block group for a
1742  	 * new index type while running (i.e. when restriping).  The running
1743  	 * case is tricky because we could race with other threads, so we need
1744  	 * to have this check to make sure we didn't already init the kobject.
1745  	 *
1746  	 * We don't have to protect on the free side because it only happens on
1747  	 * unmount.
1748  	 */
1749  	spin_lock(&space_info->lock);
1750  	if (space_info->block_group_kobjs[index]) {
1751  		spin_unlock(&space_info->lock);
1752  		kobject_put(&rkobj->kobj);
1753  		return;
1754  	} else {
1755  		space_info->block_group_kobjs[index] = &rkobj->kobj;
1756  	}
1757  	spin_unlock(&space_info->lock);
1758  
1759  	ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
1760  			  btrfs_bg_type_to_raid_name(rkobj->flags));
1761  	memalloc_nofs_restore(nofs_flag);
1762  	if (ret) {
1763  		spin_lock(&space_info->lock);
1764  		space_info->block_group_kobjs[index] = NULL;
1765  		spin_unlock(&space_info->lock);
1766  		kobject_put(&rkobj->kobj);
1767  		btrfs_warn(fs_info,
1768  			"failed to add kobject for block cache, ignoring");
1769  		return;
1770  	}
1771  }
1772  
1773  /*
1774   * Remove sysfs directories for all block group types of a given space info and
1775   * the space info as well
1776   */
1777  void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
1778  {
1779  	int i;
1780  
1781  	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1782  		struct kobject *kobj;
1783  
1784  		kobj = space_info->block_group_kobjs[i];
1785  		space_info->block_group_kobjs[i] = NULL;
1786  		if (kobj) {
1787  			kobject_del(kobj);
1788  			kobject_put(kobj);
1789  		}
1790  	}
1791  	kobject_del(&space_info->kobj);
1792  	kobject_put(&space_info->kobj);
1793  }
1794  
1795  static const char *alloc_name(u64 flags)
1796  {
1797  	switch (flags) {
1798  	case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
1799  		return "mixed";
1800  	case BTRFS_BLOCK_GROUP_METADATA:
1801  		return "metadata";
1802  	case BTRFS_BLOCK_GROUP_DATA:
1803  		return "data";
1804  	case BTRFS_BLOCK_GROUP_SYSTEM:
1805  		return "system";
1806  	default:
1807  		WARN_ON(1);
1808  		return "invalid-combination";
1809  	}
1810  }
1811  
1812  /*
1813   * Create a sysfs entry for a space info type at path
1814   * /sys/fs/btrfs/UUID/allocation/TYPE
1815   */
1816  int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
1817  				    struct btrfs_space_info *space_info)
1818  {
1819  	int ret;
1820  
1821  	ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
1822  				   fs_info->space_info_kobj, "%s",
1823  				   alloc_name(space_info->flags));
1824  	if (ret) {
1825  		kobject_put(&space_info->kobj);
1826  		return ret;
1827  	}
1828  
1829  	return 0;
1830  }
1831  
1832  void btrfs_sysfs_remove_device(struct btrfs_device *device)
1833  {
1834  	struct kobject *devices_kobj;
1835  
1836  	/*
1837  	 * Seed fs_devices devices_kobj aren't used, fetch kobject from the
1838  	 * fs_info::fs_devices.
1839  	 */
1840  	devices_kobj = device->fs_info->fs_devices->devices_kobj;
1841  	ASSERT(devices_kobj);
1842  
1843  	if (device->bdev)
1844  		sysfs_remove_link(devices_kobj, bdev_kobj(device->bdev)->name);
1845  
1846  	if (device->devid_kobj.state_initialized) {
1847  		kobject_del(&device->devid_kobj);
1848  		kobject_put(&device->devid_kobj);
1849  		wait_for_completion(&device->kobj_unregister);
1850  	}
1851  }
1852  
1853  static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj,
1854  					         struct kobj_attribute *a,
1855  					         char *buf)
1856  {
1857  	int val;
1858  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1859  						   devid_kobj);
1860  
1861  	val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
1862  
1863  	return sysfs_emit(buf, "%d\n", val);
1864  }
1865  BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show);
1866  
1867  static ssize_t btrfs_devinfo_missing_show(struct kobject *kobj,
1868  					struct kobj_attribute *a, char *buf)
1869  {
1870  	int val;
1871  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1872  						   devid_kobj);
1873  
1874  	val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
1875  
1876  	return sysfs_emit(buf, "%d\n", val);
1877  }
1878  BTRFS_ATTR(devid, missing, btrfs_devinfo_missing_show);
1879  
1880  static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj,
1881  					         struct kobj_attribute *a,
1882  					         char *buf)
1883  {
1884  	int val;
1885  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1886  						   devid_kobj);
1887  
1888  	val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
1889  
1890  	return sysfs_emit(buf, "%d\n", val);
1891  }
1892  BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show);
1893  
1894  static ssize_t btrfs_devinfo_scrub_speed_max_show(struct kobject *kobj,
1895  					     struct kobj_attribute *a,
1896  					     char *buf)
1897  {
1898  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1899  						   devid_kobj);
1900  
1901  	return sysfs_emit(buf, "%llu\n", READ_ONCE(device->scrub_speed_max));
1902  }
1903  
1904  static ssize_t btrfs_devinfo_scrub_speed_max_store(struct kobject *kobj,
1905  					      struct kobj_attribute *a,
1906  					      const char *buf, size_t len)
1907  {
1908  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1909  						   devid_kobj);
1910  	char *endptr;
1911  	unsigned long long limit;
1912  
1913  	limit = memparse(buf, &endptr);
1914  	/* There could be trailing '\n', also catch any typos after the value. */
1915  	endptr = skip_spaces(endptr);
1916  	if (*endptr != 0)
1917  		return -EINVAL;
1918  	WRITE_ONCE(device->scrub_speed_max, limit);
1919  	return len;
1920  }
1921  BTRFS_ATTR_RW(devid, scrub_speed_max, btrfs_devinfo_scrub_speed_max_show,
1922  	      btrfs_devinfo_scrub_speed_max_store);
1923  
1924  static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj,
1925  					    struct kobj_attribute *a, char *buf)
1926  {
1927  	int val;
1928  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1929  						   devid_kobj);
1930  
1931  	val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
1932  
1933  	return sysfs_emit(buf, "%d\n", val);
1934  }
1935  BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show);
1936  
1937  static ssize_t btrfs_devinfo_fsid_show(struct kobject *kobj,
1938  				       struct kobj_attribute *a, char *buf)
1939  {
1940  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1941  						   devid_kobj);
1942  
1943  	return sysfs_emit(buf, "%pU\n", device->fs_devices->fsid);
1944  }
1945  BTRFS_ATTR(devid, fsid, btrfs_devinfo_fsid_show);
1946  
1947  static ssize_t btrfs_devinfo_error_stats_show(struct kobject *kobj,
1948  		struct kobj_attribute *a, char *buf)
1949  {
1950  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1951  						   devid_kobj);
1952  
1953  	if (!device->dev_stats_valid)
1954  		return sysfs_emit(buf, "invalid\n");
1955  
1956  	/*
1957  	 * Print all at once so we get a snapshot of all values from the same
1958  	 * time. Keep them in sync and in order of definition of
1959  	 * btrfs_dev_stat_values.
1960  	 */
1961  	return sysfs_emit(buf,
1962  		"write_errs %d\n"
1963  		"read_errs %d\n"
1964  		"flush_errs %d\n"
1965  		"corruption_errs %d\n"
1966  		"generation_errs %d\n",
1967  		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_WRITE_ERRS),
1968  		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_READ_ERRS),
1969  		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_FLUSH_ERRS),
1970  		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_CORRUPTION_ERRS),
1971  		btrfs_dev_stat_read(device, BTRFS_DEV_STAT_GENERATION_ERRS));
1972  }
1973  BTRFS_ATTR(devid, error_stats, btrfs_devinfo_error_stats_show);
1974  
1975  /*
1976   * Information about one device.
1977   *
1978   * Path: /sys/fs/btrfs/<uuid>/devinfo/<devid>/
1979   */
1980  static struct attribute *devid_attrs[] = {
1981  	BTRFS_ATTR_PTR(devid, error_stats),
1982  	BTRFS_ATTR_PTR(devid, fsid),
1983  	BTRFS_ATTR_PTR(devid, in_fs_metadata),
1984  	BTRFS_ATTR_PTR(devid, missing),
1985  	BTRFS_ATTR_PTR(devid, replace_target),
1986  	BTRFS_ATTR_PTR(devid, scrub_speed_max),
1987  	BTRFS_ATTR_PTR(devid, writeable),
1988  	NULL
1989  };
1990  ATTRIBUTE_GROUPS(devid);
1991  
1992  static void btrfs_release_devid_kobj(struct kobject *kobj)
1993  {
1994  	struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1995  						   devid_kobj);
1996  
1997  	memset(&device->devid_kobj, 0, sizeof(struct kobject));
1998  	complete(&device->kobj_unregister);
1999  }
2000  
2001  static const struct kobj_type devid_ktype = {
2002  	.sysfs_ops	= &kobj_sysfs_ops,
2003  	.default_groups = devid_groups,
2004  	.release	= btrfs_release_devid_kobj,
2005  };
2006  
2007  int btrfs_sysfs_add_device(struct btrfs_device *device)
2008  {
2009  	int ret;
2010  	unsigned int nofs_flag;
2011  	struct kobject *devices_kobj;
2012  	struct kobject *devinfo_kobj;
2013  
2014  	/*
2015  	 * Make sure we use the fs_info::fs_devices to fetch the kobjects even
2016  	 * for the seed fs_devices
2017  	 */
2018  	devices_kobj = device->fs_info->fs_devices->devices_kobj;
2019  	devinfo_kobj = device->fs_info->fs_devices->devinfo_kobj;
2020  	ASSERT(devices_kobj);
2021  	ASSERT(devinfo_kobj);
2022  
2023  	nofs_flag = memalloc_nofs_save();
2024  
2025  	if (device->bdev) {
2026  		struct kobject *disk_kobj = bdev_kobj(device->bdev);
2027  
2028  		ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
2029  		if (ret) {
2030  			btrfs_warn(device->fs_info,
2031  				"creating sysfs device link for devid %llu failed: %d",
2032  				device->devid, ret);
2033  			goto out;
2034  		}
2035  	}
2036  
2037  	init_completion(&device->kobj_unregister);
2038  	ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype,
2039  				   devinfo_kobj, "%llu", device->devid);
2040  	if (ret) {
2041  		kobject_put(&device->devid_kobj);
2042  		btrfs_warn(device->fs_info,
2043  			   "devinfo init for devid %llu failed: %d",
2044  			   device->devid, ret);
2045  	}
2046  
2047  out:
2048  	memalloc_nofs_restore(nofs_flag);
2049  	return ret;
2050  }
2051  
2052  static int btrfs_sysfs_add_fs_devices(struct btrfs_fs_devices *fs_devices)
2053  {
2054  	int ret;
2055  	struct btrfs_device *device;
2056  	struct btrfs_fs_devices *seed;
2057  
2058  	list_for_each_entry(device, &fs_devices->devices, dev_list) {
2059  		ret = btrfs_sysfs_add_device(device);
2060  		if (ret)
2061  			goto fail;
2062  	}
2063  
2064  	list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
2065  		list_for_each_entry(device, &seed->devices, dev_list) {
2066  			ret = btrfs_sysfs_add_device(device);
2067  			if (ret)
2068  				goto fail;
2069  		}
2070  	}
2071  
2072  	return 0;
2073  
2074  fail:
2075  	btrfs_sysfs_remove_fs_devices(fs_devices);
2076  	return ret;
2077  }
2078  
2079  void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
2080  {
2081  	int ret;
2082  
2083  	ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
2084  	if (ret)
2085  		pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
2086  			action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
2087  			&disk_to_dev(bdev->bd_disk)->kobj);
2088  }
2089  
2090  void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices)
2091  
2092  {
2093  	char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2094  
2095  	/*
2096  	 * Sprouting changes fsid of the mounted filesystem, rename the fsid
2097  	 * directory
2098  	 */
2099  	snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fs_devices->fsid);
2100  	if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
2101  		btrfs_warn(fs_devices->fs_info,
2102  				"sysfs: failed to create fsid for sprout");
2103  }
2104  
2105  void btrfs_sysfs_update_devid(struct btrfs_device *device)
2106  {
2107  	char tmp[24];
2108  
2109  	snprintf(tmp, sizeof(tmp), "%llu", device->devid);
2110  
2111  	if (kobject_rename(&device->devid_kobj, tmp))
2112  		btrfs_warn(device->fs_devices->fs_info,
2113  			   "sysfs: failed to update devid for %llu",
2114  			   device->devid);
2115  }
2116  
2117  /* /sys/fs/btrfs/ entry */
2118  static struct kset *btrfs_kset;
2119  
2120  /*
2121   * Creates:
2122   *		/sys/fs/btrfs/UUID
2123   *
2124   * Can be called by the device discovery thread.
2125   */
2126  int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
2127  {
2128  	int error;
2129  
2130  	init_completion(&fs_devs->kobj_unregister);
2131  	fs_devs->fsid_kobj.kset = btrfs_kset;
2132  	error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
2133  				     "%pU", fs_devs->fsid);
2134  	if (error) {
2135  		kobject_put(&fs_devs->fsid_kobj);
2136  		return error;
2137  	}
2138  
2139  	fs_devs->devices_kobj = kobject_create_and_add("devices",
2140  						       &fs_devs->fsid_kobj);
2141  	if (!fs_devs->devices_kobj) {
2142  		btrfs_err(fs_devs->fs_info,
2143  			  "failed to init sysfs device interface");
2144  		btrfs_sysfs_remove_fsid(fs_devs);
2145  		return -ENOMEM;
2146  	}
2147  
2148  	fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
2149  						       &fs_devs->fsid_kobj);
2150  	if (!fs_devs->devinfo_kobj) {
2151  		btrfs_err(fs_devs->fs_info,
2152  			  "failed to init sysfs devinfo kobject");
2153  		btrfs_sysfs_remove_fsid(fs_devs);
2154  		return -ENOMEM;
2155  	}
2156  
2157  	return 0;
2158  }
2159  
2160  int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
2161  {
2162  	int error;
2163  	struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
2164  	struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
2165  
2166  	error = btrfs_sysfs_add_fs_devices(fs_devs);
2167  	if (error)
2168  		return error;
2169  
2170  	error = sysfs_create_files(fsid_kobj, btrfs_attrs);
2171  	if (error) {
2172  		btrfs_sysfs_remove_fs_devices(fs_devs);
2173  		return error;
2174  	}
2175  
2176  	error = sysfs_create_group(fsid_kobj,
2177  				   &btrfs_feature_attr_group);
2178  	if (error)
2179  		goto failure;
2180  
2181  #ifdef CONFIG_BTRFS_DEBUG
2182  	fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
2183  	if (!fs_info->debug_kobj) {
2184  		error = -ENOMEM;
2185  		goto failure;
2186  	}
2187  
2188  	error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
2189  	if (error)
2190  		goto failure;
2191  #endif
2192  
2193  	/* Discard directory */
2194  	fs_info->discard_kobj = kobject_create_and_add("discard", fsid_kobj);
2195  	if (!fs_info->discard_kobj) {
2196  		error = -ENOMEM;
2197  		goto failure;
2198  	}
2199  
2200  	error = sysfs_create_files(fs_info->discard_kobj, discard_attrs);
2201  	if (error)
2202  		goto failure;
2203  
2204  	error = addrm_unknown_feature_attrs(fs_info, true);
2205  	if (error)
2206  		goto failure;
2207  
2208  	error = sysfs_create_link(fsid_kobj, &fs_info->sb->s_bdi->dev->kobj, "bdi");
2209  	if (error)
2210  		goto failure;
2211  
2212  	fs_info->space_info_kobj = kobject_create_and_add("allocation",
2213  						  fsid_kobj);
2214  	if (!fs_info->space_info_kobj) {
2215  		error = -ENOMEM;
2216  		goto failure;
2217  	}
2218  
2219  	error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
2220  	if (error)
2221  		goto failure;
2222  
2223  	return 0;
2224  failure:
2225  	btrfs_sysfs_remove_mounted(fs_info);
2226  	return error;
2227  }
2228  
2229  static ssize_t qgroup_enabled_show(struct kobject *qgroups_kobj,
2230  				   struct kobj_attribute *a,
2231  				   char *buf)
2232  {
2233  	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2234  	bool enabled;
2235  
2236  	spin_lock(&fs_info->qgroup_lock);
2237  	enabled = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON;
2238  	spin_unlock(&fs_info->qgroup_lock);
2239  
2240  	return sysfs_emit(buf, "%d\n", enabled);
2241  }
2242  BTRFS_ATTR(qgroups, enabled, qgroup_enabled_show);
2243  
2244  static ssize_t qgroup_mode_show(struct kobject *qgroups_kobj,
2245  				struct kobj_attribute *a,
2246  				char *buf)
2247  {
2248  	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2249  	ssize_t ret = 0;
2250  
2251  	spin_lock(&fs_info->qgroup_lock);
2252  	ASSERT(btrfs_qgroup_enabled(fs_info));
2253  	switch (btrfs_qgroup_mode(fs_info)) {
2254  	case BTRFS_QGROUP_MODE_FULL:
2255  		ret = sysfs_emit(buf, "qgroup\n");
2256  		break;
2257  	case BTRFS_QGROUP_MODE_SIMPLE:
2258  		ret = sysfs_emit(buf, "squota\n");
2259  		break;
2260  	default:
2261  		btrfs_warn(fs_info, "unexpected qgroup mode %d\n",
2262  			   btrfs_qgroup_mode(fs_info));
2263  		break;
2264  	}
2265  	spin_unlock(&fs_info->qgroup_lock);
2266  
2267  	return ret;
2268  }
2269  BTRFS_ATTR(qgroups, mode, qgroup_mode_show);
2270  
2271  static ssize_t qgroup_inconsistent_show(struct kobject *qgroups_kobj,
2272  					struct kobj_attribute *a,
2273  					char *buf)
2274  {
2275  	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2276  	bool inconsistent;
2277  
2278  	spin_lock(&fs_info->qgroup_lock);
2279  	inconsistent = (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT);
2280  	spin_unlock(&fs_info->qgroup_lock);
2281  
2282  	return sysfs_emit(buf, "%d\n", inconsistent);
2283  }
2284  BTRFS_ATTR(qgroups, inconsistent, qgroup_inconsistent_show);
2285  
2286  static ssize_t qgroup_drop_subtree_thres_show(struct kobject *qgroups_kobj,
2287  					      struct kobj_attribute *a,
2288  					      char *buf)
2289  {
2290  	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2291  	u8 result;
2292  
2293  	spin_lock(&fs_info->qgroup_lock);
2294  	result = fs_info->qgroup_drop_subtree_thres;
2295  	spin_unlock(&fs_info->qgroup_lock);
2296  
2297  	return sysfs_emit(buf, "%d\n", result);
2298  }
2299  
2300  static ssize_t qgroup_drop_subtree_thres_store(struct kobject *qgroups_kobj,
2301  					       struct kobj_attribute *a,
2302  					       const char *buf, size_t len)
2303  {
2304  	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2305  	u8 new_thres;
2306  	int ret;
2307  
2308  	ret = kstrtou8(buf, 10, &new_thres);
2309  	if (ret)
2310  		return -EINVAL;
2311  
2312  	if (new_thres > BTRFS_MAX_LEVEL)
2313  		return -EINVAL;
2314  
2315  	spin_lock(&fs_info->qgroup_lock);
2316  	fs_info->qgroup_drop_subtree_thres = new_thres;
2317  	spin_unlock(&fs_info->qgroup_lock);
2318  
2319  	return len;
2320  }
2321  BTRFS_ATTR_RW(qgroups, drop_subtree_threshold, qgroup_drop_subtree_thres_show,
2322  	      qgroup_drop_subtree_thres_store);
2323  
2324  /*
2325   * Qgroups global info
2326   *
2327   * Path: /sys/fs/btrfs/<uuid>/qgroups/
2328   */
2329  static struct attribute *qgroups_attrs[] = {
2330  	BTRFS_ATTR_PTR(qgroups, enabled),
2331  	BTRFS_ATTR_PTR(qgroups, inconsistent),
2332  	BTRFS_ATTR_PTR(qgroups, drop_subtree_threshold),
2333  	BTRFS_ATTR_PTR(qgroups, mode),
2334  	NULL
2335  };
2336  ATTRIBUTE_GROUPS(qgroups);
2337  
2338  static void qgroups_release(struct kobject *kobj)
2339  {
2340  	kfree(kobj);
2341  }
2342  
2343  static const struct kobj_type qgroups_ktype = {
2344  	.sysfs_ops = &kobj_sysfs_ops,
2345  	.default_groups = qgroups_groups,
2346  	.release = qgroups_release,
2347  };
2348  
2349  static inline struct btrfs_fs_info *qgroup_kobj_to_fs_info(struct kobject *kobj)
2350  {
2351  	return to_fs_info(kobj->parent->parent);
2352  }
2353  
2354  #define QGROUP_ATTR(_member, _show_name)					\
2355  static ssize_t btrfs_qgroup_show_##_member(struct kobject *qgroup_kobj,		\
2356  					   struct kobj_attribute *a,		\
2357  					   char *buf)				\
2358  {										\
2359  	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2360  	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2361  			struct btrfs_qgroup, kobj);				\
2362  	return btrfs_show_u64(&qgroup->_member, &fs_info->qgroup_lock, buf);	\
2363  }										\
2364  BTRFS_ATTR(qgroup, _show_name, btrfs_qgroup_show_##_member)
2365  
2366  #define QGROUP_RSV_ATTR(_name, _type)						\
2367  static ssize_t btrfs_qgroup_rsv_show_##_name(struct kobject *qgroup_kobj,	\
2368  					     struct kobj_attribute *a,		\
2369  					     char *buf)				\
2370  {										\
2371  	struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);	\
2372  	struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,			\
2373  			struct btrfs_qgroup, kobj);				\
2374  	return btrfs_show_u64(&qgroup->rsv.values[_type],			\
2375  			&fs_info->qgroup_lock, buf);				\
2376  }										\
2377  BTRFS_ATTR(qgroup, rsv_##_name, btrfs_qgroup_rsv_show_##_name)
2378  
2379  QGROUP_ATTR(rfer, referenced);
2380  QGROUP_ATTR(excl, exclusive);
2381  QGROUP_ATTR(max_rfer, max_referenced);
2382  QGROUP_ATTR(max_excl, max_exclusive);
2383  QGROUP_ATTR(lim_flags, limit_flags);
2384  QGROUP_RSV_ATTR(data, BTRFS_QGROUP_RSV_DATA);
2385  QGROUP_RSV_ATTR(meta_pertrans, BTRFS_QGROUP_RSV_META_PERTRANS);
2386  QGROUP_RSV_ATTR(meta_prealloc, BTRFS_QGROUP_RSV_META_PREALLOC);
2387  
2388  /*
2389   * Qgroup information.
2390   *
2391   * Path: /sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>/
2392   */
2393  static struct attribute *qgroup_attrs[] = {
2394  	BTRFS_ATTR_PTR(qgroup, referenced),
2395  	BTRFS_ATTR_PTR(qgroup, exclusive),
2396  	BTRFS_ATTR_PTR(qgroup, max_referenced),
2397  	BTRFS_ATTR_PTR(qgroup, max_exclusive),
2398  	BTRFS_ATTR_PTR(qgroup, limit_flags),
2399  	BTRFS_ATTR_PTR(qgroup, rsv_data),
2400  	BTRFS_ATTR_PTR(qgroup, rsv_meta_pertrans),
2401  	BTRFS_ATTR_PTR(qgroup, rsv_meta_prealloc),
2402  	NULL
2403  };
2404  ATTRIBUTE_GROUPS(qgroup);
2405  
2406  static void qgroup_release(struct kobject *kobj)
2407  {
2408  	struct btrfs_qgroup *qgroup = container_of(kobj, struct btrfs_qgroup, kobj);
2409  
2410  	memset(&qgroup->kobj, 0, sizeof(*kobj));
2411  }
2412  
2413  static const struct kobj_type qgroup_ktype = {
2414  	.sysfs_ops = &kobj_sysfs_ops,
2415  	.release = qgroup_release,
2416  	.default_groups = qgroup_groups,
2417  };
2418  
2419  int btrfs_sysfs_add_one_qgroup(struct btrfs_fs_info *fs_info,
2420  				struct btrfs_qgroup *qgroup)
2421  {
2422  	struct kobject *qgroups_kobj = fs_info->qgroups_kobj;
2423  	int ret;
2424  
2425  	if (btrfs_is_testing(fs_info))
2426  		return 0;
2427  	if (qgroup->kobj.state_initialized)
2428  		return 0;
2429  	if (!qgroups_kobj)
2430  		return -EINVAL;
2431  
2432  	ret = kobject_init_and_add(&qgroup->kobj, &qgroup_ktype, qgroups_kobj,
2433  			"%hu_%llu", btrfs_qgroup_level(qgroup->qgroupid),
2434  			btrfs_qgroup_subvolid(qgroup->qgroupid));
2435  	if (ret < 0)
2436  		kobject_put(&qgroup->kobj);
2437  
2438  	return ret;
2439  }
2440  
2441  void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info)
2442  {
2443  	struct btrfs_qgroup *qgroup;
2444  	struct btrfs_qgroup *next;
2445  
2446  	if (btrfs_is_testing(fs_info))
2447  		return;
2448  
2449  	rbtree_postorder_for_each_entry_safe(qgroup, next,
2450  					     &fs_info->qgroup_tree, node)
2451  		btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
2452  	if (fs_info->qgroups_kobj) {
2453  		kobject_del(fs_info->qgroups_kobj);
2454  		kobject_put(fs_info->qgroups_kobj);
2455  		fs_info->qgroups_kobj = NULL;
2456  	}
2457  }
2458  
2459  /* Called when qgroups get initialized, thus there is no need for locking */
2460  int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info)
2461  {
2462  	struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2463  	struct btrfs_qgroup *qgroup;
2464  	struct btrfs_qgroup *next;
2465  	int ret = 0;
2466  
2467  	if (btrfs_is_testing(fs_info))
2468  		return 0;
2469  
2470  	ASSERT(fsid_kobj);
2471  	if (fs_info->qgroups_kobj)
2472  		return 0;
2473  
2474  	fs_info->qgroups_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
2475  	if (!fs_info->qgroups_kobj)
2476  		return -ENOMEM;
2477  
2478  	ret = kobject_init_and_add(fs_info->qgroups_kobj, &qgroups_ktype,
2479  				   fsid_kobj, "qgroups");
2480  	if (ret < 0)
2481  		goto out;
2482  
2483  	rbtree_postorder_for_each_entry_safe(qgroup, next,
2484  					     &fs_info->qgroup_tree, node) {
2485  		ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
2486  		if (ret < 0)
2487  			goto out;
2488  	}
2489  
2490  out:
2491  	if (ret < 0)
2492  		btrfs_sysfs_del_qgroups(fs_info);
2493  	return ret;
2494  }
2495  
2496  void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
2497  				struct btrfs_qgroup *qgroup)
2498  {
2499  	if (btrfs_is_testing(fs_info))
2500  		return;
2501  
2502  	if (qgroup->kobj.state_initialized) {
2503  		kobject_del(&qgroup->kobj);
2504  		kobject_put(&qgroup->kobj);
2505  	}
2506  }
2507  
2508  /*
2509   * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
2510   * values in superblock. Call after any changes to incompat/compat_ro flags
2511   */
2512  void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info)
2513  {
2514  	struct kobject *fsid_kobj;
2515  	int ret;
2516  
2517  	if (!fs_info)
2518  		return;
2519  
2520  	fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2521  	if (!fsid_kobj->state_initialized)
2522  		return;
2523  
2524  	ret = sysfs_update_group(fsid_kobj, &btrfs_feature_attr_group);
2525  	if (ret < 0)
2526  		btrfs_warn(fs_info,
2527  			   "failed to update /sys/fs/btrfs/%pU/features: %d",
2528  			   fs_info->fs_devices->fsid, ret);
2529  }
2530  
2531  int __init btrfs_init_sysfs(void)
2532  {
2533  	int ret;
2534  
2535  	btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
2536  	if (!btrfs_kset)
2537  		return -ENOMEM;
2538  
2539  	init_feature_attrs();
2540  	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2541  	if (ret)
2542  		goto out2;
2543  	ret = sysfs_merge_group(&btrfs_kset->kobj,
2544  				&btrfs_static_feature_attr_group);
2545  	if (ret)
2546  		goto out_remove_group;
2547  
2548  #ifdef CONFIG_BTRFS_DEBUG
2549  	ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2550  	if (ret) {
2551  		sysfs_unmerge_group(&btrfs_kset->kobj,
2552  				    &btrfs_static_feature_attr_group);
2553  		goto out_remove_group;
2554  	}
2555  #endif
2556  
2557  	return 0;
2558  
2559  out_remove_group:
2560  	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2561  out2:
2562  	kset_unregister(btrfs_kset);
2563  
2564  	return ret;
2565  }
2566  
2567  void __cold btrfs_exit_sysfs(void)
2568  {
2569  	sysfs_unmerge_group(&btrfs_kset->kobj,
2570  			    &btrfs_static_feature_attr_group);
2571  	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2572  #ifdef CONFIG_BTRFS_DEBUG
2573  	sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2574  #endif
2575  	kset_unregister(btrfs_kset);
2576  }
2577