4848a4318fb5429ada1e83114c48e99822f121df
[sfrench/cifs-2.6.git] / fs / btrfs / sysfs.c
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/slab.h>
8 #include <linux/spinlock.h>
9 #include <linux/completion.h>
10 #include <linux/buffer_head.h>
11 #include <linux/kobject.h>
12 #include <linux/bug.h>
13 #include <linux/genhd.h>
14 #include <linux/debugfs.h>
15
16 #include "ctree.h"
17 #include "disk-io.h"
18 #include "transaction.h"
19 #include "sysfs.h"
20 #include "volumes.h"
21
22 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
23 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
24
25 static u64 get_features(struct btrfs_fs_info *fs_info,
26                         enum btrfs_feature_set set)
27 {
28         struct btrfs_super_block *disk_super = fs_info->super_copy;
29         if (set == FEAT_COMPAT)
30                 return btrfs_super_compat_flags(disk_super);
31         else if (set == FEAT_COMPAT_RO)
32                 return btrfs_super_compat_ro_flags(disk_super);
33         else
34                 return btrfs_super_incompat_flags(disk_super);
35 }
36
37 static void set_features(struct btrfs_fs_info *fs_info,
38                          enum btrfs_feature_set set, u64 features)
39 {
40         struct btrfs_super_block *disk_super = fs_info->super_copy;
41         if (set == FEAT_COMPAT)
42                 btrfs_set_super_compat_flags(disk_super, features);
43         else if (set == FEAT_COMPAT_RO)
44                 btrfs_set_super_compat_ro_flags(disk_super, features);
45         else
46                 btrfs_set_super_incompat_flags(disk_super, features);
47 }
48
49 static int can_modify_feature(struct btrfs_feature_attr *fa)
50 {
51         int val = 0;
52         u64 set, clear;
53         switch (fa->feature_set) {
54         case FEAT_COMPAT:
55                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
56                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
57                 break;
58         case FEAT_COMPAT_RO:
59                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
60                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
61                 break;
62         case FEAT_INCOMPAT:
63                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
64                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
65                 break;
66         default:
67                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
68                                 fa->feature_set);
69                 return 0;
70         }
71
72         if (set & fa->feature_bit)
73                 val |= 1;
74         if (clear & fa->feature_bit)
75                 val |= 2;
76
77         return val;
78 }
79
80 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
81                                        struct kobj_attribute *a, char *buf)
82 {
83         int val = 0;
84         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
85         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
86         if (fs_info) {
87                 u64 features = get_features(fs_info, fa->feature_set);
88                 if (features & fa->feature_bit)
89                         val = 1;
90         } else
91                 val = can_modify_feature(fa);
92
93         return snprintf(buf, PAGE_SIZE, "%d\n", val);
94 }
95
96 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
97                                         struct kobj_attribute *a,
98                                         const char *buf, size_t count)
99 {
100         struct btrfs_fs_info *fs_info;
101         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
102         u64 features, set, clear;
103         unsigned long val;
104         int ret;
105
106         fs_info = to_fs_info(kobj);
107         if (!fs_info)
108                 return -EPERM;
109
110         if (sb_rdonly(fs_info->sb))
111                 return -EROFS;
112
113         ret = kstrtoul(skip_spaces(buf), 0, &val);
114         if (ret)
115                 return ret;
116
117         if (fa->feature_set == FEAT_COMPAT) {
118                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
119                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
120         } else if (fa->feature_set == FEAT_COMPAT_RO) {
121                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
122                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
123         } else {
124                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
125                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
126         }
127
128         features = get_features(fs_info, fa->feature_set);
129
130         /* Nothing to do */
131         if ((val && (features & fa->feature_bit)) ||
132             (!val && !(features & fa->feature_bit)))
133                 return count;
134
135         if ((val && !(set & fa->feature_bit)) ||
136             (!val && !(clear & fa->feature_bit))) {
137                 btrfs_info(fs_info,
138                         "%sabling feature %s on mounted fs is not supported.",
139                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
140                 return -EPERM;
141         }
142
143         btrfs_info(fs_info, "%s %s feature flag",
144                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
145
146         spin_lock(&fs_info->super_lock);
147         features = get_features(fs_info, fa->feature_set);
148         if (val)
149                 features |= fa->feature_bit;
150         else
151                 features &= ~fa->feature_bit;
152         set_features(fs_info, fa->feature_set, features);
153         spin_unlock(&fs_info->super_lock);
154
155         /*
156          * We don't want to do full transaction commit from inside sysfs
157          */
158         btrfs_set_pending(fs_info, COMMIT);
159         wake_up_process(fs_info->transaction_kthread);
160
161         return count;
162 }
163
164 static umode_t btrfs_feature_visible(struct kobject *kobj,
165                                      struct attribute *attr, int unused)
166 {
167         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
168         umode_t mode = attr->mode;
169
170         if (fs_info) {
171                 struct btrfs_feature_attr *fa;
172                 u64 features;
173
174                 fa = attr_to_btrfs_feature_attr(attr);
175                 features = get_features(fs_info, fa->feature_set);
176
177                 if (can_modify_feature(fa))
178                         mode |= S_IWUSR;
179                 else if (!(features & fa->feature_bit))
180                         mode = 0;
181         }
182
183         return mode;
184 }
185
186 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
187 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
188 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
189 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
190 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
191 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
192 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
193 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
194 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
195 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
196 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
197
198 static struct attribute *btrfs_supported_feature_attrs[] = {
199         BTRFS_FEAT_ATTR_PTR(mixed_backref),
200         BTRFS_FEAT_ATTR_PTR(default_subvol),
201         BTRFS_FEAT_ATTR_PTR(mixed_groups),
202         BTRFS_FEAT_ATTR_PTR(compress_lzo),
203         BTRFS_FEAT_ATTR_PTR(compress_zstd),
204         BTRFS_FEAT_ATTR_PTR(big_metadata),
205         BTRFS_FEAT_ATTR_PTR(extended_iref),
206         BTRFS_FEAT_ATTR_PTR(raid56),
207         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
208         BTRFS_FEAT_ATTR_PTR(no_holes),
209         BTRFS_FEAT_ATTR_PTR(free_space_tree),
210         NULL
211 };
212
213 static const struct attribute_group btrfs_feature_attr_group = {
214         .name = "features",
215         .is_visible = btrfs_feature_visible,
216         .attrs = btrfs_supported_feature_attrs,
217 };
218
219 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
220 {
221         u64 val;
222         if (lock)
223                 spin_lock(lock);
224         val = *value_ptr;
225         if (lock)
226                 spin_unlock(lock);
227         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
228 }
229
230 static ssize_t global_rsv_size_show(struct kobject *kobj,
231                                     struct kobj_attribute *ka, char *buf)
232 {
233         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
234         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
235         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
236 }
237 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
238
239 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
240                                         struct kobj_attribute *a, char *buf)
241 {
242         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
243         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
244         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
245 }
246 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
247
248 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
249 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
250
251 static ssize_t raid_bytes_show(struct kobject *kobj,
252                                struct kobj_attribute *attr, char *buf);
253 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
254 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
255
256 static ssize_t raid_bytes_show(struct kobject *kobj,
257                                struct kobj_attribute *attr, char *buf)
258
259 {
260         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
261         struct btrfs_block_group_cache *block_group;
262         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
263         u64 val = 0;
264
265         down_read(&sinfo->groups_sem);
266         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
267                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
268                         val += block_group->key.offset;
269                 else
270                         val += btrfs_block_group_used(&block_group->item);
271         }
272         up_read(&sinfo->groups_sem);
273         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
274 }
275
276 static struct attribute *raid_attributes[] = {
277         BTRFS_ATTR_PTR(raid, total_bytes),
278         BTRFS_ATTR_PTR(raid, used_bytes),
279         NULL
280 };
281
282 static void release_raid_kobj(struct kobject *kobj)
283 {
284         kfree(to_raid_kobj(kobj));
285 }
286
287 struct kobj_type btrfs_raid_ktype = {
288         .sysfs_ops = &kobj_sysfs_ops,
289         .release = release_raid_kobj,
290         .default_attrs = raid_attributes,
291 };
292
293 #define SPACE_INFO_ATTR(field)                                          \
294 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
295                                              struct kobj_attribute *a,  \
296                                              char *buf)                 \
297 {                                                                       \
298         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
299         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
300 }                                                                       \
301 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
302
303 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
304                                                        struct kobj_attribute *a,
305                                                        char *buf)
306 {
307         struct btrfs_space_info *sinfo = to_space_info(kobj);
308         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
309         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
310 }
311
312 SPACE_INFO_ATTR(flags);
313 SPACE_INFO_ATTR(total_bytes);
314 SPACE_INFO_ATTR(bytes_used);
315 SPACE_INFO_ATTR(bytes_pinned);
316 SPACE_INFO_ATTR(bytes_reserved);
317 SPACE_INFO_ATTR(bytes_may_use);
318 SPACE_INFO_ATTR(bytes_readonly);
319 SPACE_INFO_ATTR(disk_used);
320 SPACE_INFO_ATTR(disk_total);
321 BTRFS_ATTR(space_info, total_bytes_pinned,
322            btrfs_space_info_show_total_bytes_pinned);
323
324 static struct attribute *space_info_attrs[] = {
325         BTRFS_ATTR_PTR(space_info, flags),
326         BTRFS_ATTR_PTR(space_info, total_bytes),
327         BTRFS_ATTR_PTR(space_info, bytes_used),
328         BTRFS_ATTR_PTR(space_info, bytes_pinned),
329         BTRFS_ATTR_PTR(space_info, bytes_reserved),
330         BTRFS_ATTR_PTR(space_info, bytes_may_use),
331         BTRFS_ATTR_PTR(space_info, bytes_readonly),
332         BTRFS_ATTR_PTR(space_info, disk_used),
333         BTRFS_ATTR_PTR(space_info, disk_total),
334         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
335         NULL,
336 };
337
338 static void space_info_release(struct kobject *kobj)
339 {
340         struct btrfs_space_info *sinfo = to_space_info(kobj);
341         percpu_counter_destroy(&sinfo->total_bytes_pinned);
342         kfree(sinfo);
343 }
344
345 struct kobj_type space_info_ktype = {
346         .sysfs_ops = &kobj_sysfs_ops,
347         .release = space_info_release,
348         .default_attrs = space_info_attrs,
349 };
350
351 static const struct attribute *allocation_attrs[] = {
352         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
353         BTRFS_ATTR_PTR(allocation, global_rsv_size),
354         NULL,
355 };
356
357 static ssize_t btrfs_label_show(struct kobject *kobj,
358                                 struct kobj_attribute *a, char *buf)
359 {
360         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
361         char *label = fs_info->super_copy->label;
362         ssize_t ret;
363
364         spin_lock(&fs_info->super_lock);
365         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
366         spin_unlock(&fs_info->super_lock);
367
368         return ret;
369 }
370
371 static ssize_t btrfs_label_store(struct kobject *kobj,
372                                  struct kobj_attribute *a,
373                                  const char *buf, size_t len)
374 {
375         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
376         size_t p_len;
377
378         if (!fs_info)
379                 return -EPERM;
380
381         if (sb_rdonly(fs_info->sb))
382                 return -EROFS;
383
384         /*
385          * p_len is the len until the first occurrence of either
386          * '\n' or '\0'
387          */
388         p_len = strcspn(buf, "\n");
389
390         if (p_len >= BTRFS_LABEL_SIZE)
391                 return -EINVAL;
392
393         spin_lock(&fs_info->super_lock);
394         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
395         memcpy(fs_info->super_copy->label, buf, p_len);
396         spin_unlock(&fs_info->super_lock);
397
398         /*
399          * We don't want to do full transaction commit from inside sysfs
400          */
401         btrfs_set_pending(fs_info, COMMIT);
402         wake_up_process(fs_info->transaction_kthread);
403
404         return len;
405 }
406 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
407
408 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
409                                 struct kobj_attribute *a, char *buf)
410 {
411         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
412
413         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
414 }
415
416 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
417
418 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
419                                 struct kobj_attribute *a, char *buf)
420 {
421         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
422
423         return snprintf(buf, PAGE_SIZE, "%u\n",
424                         fs_info->super_copy->sectorsize);
425 }
426
427 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
428
429 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
430                                 struct kobj_attribute *a, char *buf)
431 {
432         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
433
434         return snprintf(buf, PAGE_SIZE, "%u\n",
435                         fs_info->super_copy->sectorsize);
436 }
437
438 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
439
440 static ssize_t quota_override_show(struct kobject *kobj,
441                                    struct kobj_attribute *a, char *buf)
442 {
443         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
444         int quota_override;
445
446         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
447         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
448 }
449
450 static ssize_t quota_override_store(struct kobject *kobj,
451                                     struct kobj_attribute *a,
452                                     const char *buf, size_t len)
453 {
454         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
455         unsigned long knob;
456         int err;
457
458         if (!fs_info)
459                 return -EPERM;
460
461         if (!capable(CAP_SYS_RESOURCE))
462                 return -EPERM;
463
464         err = kstrtoul(buf, 10, &knob);
465         if (err)
466                 return err;
467         if (knob > 1)
468                 return -EINVAL;
469
470         if (knob)
471                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
472         else
473                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
474
475         return len;
476 }
477
478 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
479
480 static const struct attribute *btrfs_attrs[] = {
481         BTRFS_ATTR_PTR(, label),
482         BTRFS_ATTR_PTR(, nodesize),
483         BTRFS_ATTR_PTR(, sectorsize),
484         BTRFS_ATTR_PTR(, clone_alignment),
485         BTRFS_ATTR_PTR(, quota_override),
486         NULL,
487 };
488
489 static void btrfs_release_fsid_kobj(struct kobject *kobj)
490 {
491         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
492
493         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
494         complete(&fs_devs->kobj_unregister);
495 }
496
497 static struct kobj_type btrfs_ktype = {
498         .sysfs_ops      = &kobj_sysfs_ops,
499         .release        = btrfs_release_fsid_kobj,
500 };
501
502 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
503 {
504         if (kobj->ktype != &btrfs_ktype)
505                 return NULL;
506         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
507 }
508
509 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
510 {
511         if (kobj->ktype != &btrfs_ktype)
512                 return NULL;
513         return to_fs_devs(kobj)->fs_info;
514 }
515
516 #define NUM_FEATURE_BITS 64
517 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
518 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
519
520 static const u64 supported_feature_masks[3] = {
521         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
522         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
523         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
524 };
525
526 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
527 {
528         int set;
529
530         for (set = 0; set < FEAT_MAX; set++) {
531                 int i;
532                 struct attribute *attrs[2];
533                 struct attribute_group agroup = {
534                         .name = "features",
535                         .attrs = attrs,
536                 };
537                 u64 features = get_features(fs_info, set);
538                 features &= ~supported_feature_masks[set];
539
540                 if (!features)
541                         continue;
542
543                 attrs[1] = NULL;
544                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
545                         struct btrfs_feature_attr *fa;
546
547                         if (!(features & (1ULL << i)))
548                                 continue;
549
550                         fa = &btrfs_feature_attrs[set][i];
551                         attrs[0] = &fa->kobj_attr.attr;
552                         if (add) {
553                                 int ret;
554                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
555                                                         &agroup);
556                                 if (ret)
557                                         return ret;
558                         } else
559                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
560                                                     &agroup);
561                 }
562
563         }
564         return 0;
565 }
566
567 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
568 {
569         if (fs_devs->device_dir_kobj) {
570                 kobject_del(fs_devs->device_dir_kobj);
571                 kobject_put(fs_devs->device_dir_kobj);
572                 fs_devs->device_dir_kobj = NULL;
573         }
574
575         if (fs_devs->fsid_kobj.state_initialized) {
576                 kobject_del(&fs_devs->fsid_kobj);
577                 kobject_put(&fs_devs->fsid_kobj);
578                 wait_for_completion(&fs_devs->kobj_unregister);
579         }
580 }
581
582 /* when fs_devs is NULL it will remove all fsid kobject */
583 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
584 {
585         struct list_head *fs_uuids = btrfs_get_fs_uuids();
586
587         if (fs_devs) {
588                 __btrfs_sysfs_remove_fsid(fs_devs);
589                 return;
590         }
591
592         list_for_each_entry(fs_devs, fs_uuids, list) {
593                 __btrfs_sysfs_remove_fsid(fs_devs);
594         }
595 }
596
597 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
598 {
599         btrfs_reset_fs_info_ptr(fs_info);
600
601         if (fs_info->space_info_kobj) {
602                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
603                 kobject_del(fs_info->space_info_kobj);
604                 kobject_put(fs_info->space_info_kobj);
605         }
606         addrm_unknown_feature_attrs(fs_info, false);
607         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
608         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
609         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
610 }
611
612 const char * const btrfs_feature_set_names[3] = {
613         [FEAT_COMPAT]    = "compat",
614         [FEAT_COMPAT_RO] = "compat_ro",
615         [FEAT_INCOMPAT]  = "incompat",
616 };
617
618 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
619 {
620         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
621         int len = 0;
622         int i;
623         char *str;
624
625         str = kmalloc(bufsize, GFP_KERNEL);
626         if (!str)
627                 return str;
628
629         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
630                 const char *name;
631
632                 if (!(flags & (1ULL << i)))
633                         continue;
634
635                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
636                 len += snprintf(str + len, bufsize - len, "%s%s",
637                                 len ? "," : "", name);
638         }
639
640         return str;
641 }
642
643 static void init_feature_attrs(void)
644 {
645         struct btrfs_feature_attr *fa;
646         int set, i;
647
648         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
649                      ARRAY_SIZE(btrfs_feature_attrs));
650         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
651                      ARRAY_SIZE(btrfs_feature_attrs[0]));
652
653         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
654         memset(btrfs_unknown_feature_names, 0,
655                sizeof(btrfs_unknown_feature_names));
656
657         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
658                 struct btrfs_feature_attr *sfa;
659                 struct attribute *a = btrfs_supported_feature_attrs[i];
660                 int bit;
661                 sfa = attr_to_btrfs_feature_attr(a);
662                 bit = ilog2(sfa->feature_bit);
663                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
664
665                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
666         }
667
668         for (set = 0; set < FEAT_MAX; set++) {
669                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
670                         char *name = btrfs_unknown_feature_names[set][i];
671                         fa = &btrfs_feature_attrs[set][i];
672
673                         if (fa->kobj_attr.attr.name)
674                                 continue;
675
676                         snprintf(name, 13, "%s:%u",
677                                  btrfs_feature_set_names[set], i);
678
679                         fa->kobj_attr.attr.name = name;
680                         fa->kobj_attr.attr.mode = S_IRUGO;
681                         fa->feature_set = set;
682                         fa->feature_bit = 1ULL << i;
683                 }
684         }
685 }
686
687 /* when one_device is NULL, it removes all device links */
688
689 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
690                 struct btrfs_device *one_device)
691 {
692         struct hd_struct *disk;
693         struct kobject *disk_kobj;
694
695         if (!fs_devices->device_dir_kobj)
696                 return -EINVAL;
697
698         if (one_device && one_device->bdev) {
699                 disk = one_device->bdev->bd_part;
700                 disk_kobj = &part_to_dev(disk)->kobj;
701
702                 sysfs_remove_link(fs_devices->device_dir_kobj,
703                                                 disk_kobj->name);
704         }
705
706         if (one_device)
707                 return 0;
708
709         list_for_each_entry(one_device,
710                         &fs_devices->devices, dev_list) {
711                 if (!one_device->bdev)
712                         continue;
713                 disk = one_device->bdev->bd_part;
714                 disk_kobj = &part_to_dev(disk)->kobj;
715
716                 sysfs_remove_link(fs_devices->device_dir_kobj,
717                                                 disk_kobj->name);
718         }
719
720         return 0;
721 }
722
723 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
724 {
725         if (!fs_devs->device_dir_kobj)
726                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
727                                                 &fs_devs->fsid_kobj);
728
729         if (!fs_devs->device_dir_kobj)
730                 return -ENOMEM;
731
732         return 0;
733 }
734
735 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
736                                 struct btrfs_device *one_device)
737 {
738         int error = 0;
739         struct btrfs_device *dev;
740
741         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
742                 struct hd_struct *disk;
743                 struct kobject *disk_kobj;
744
745                 if (!dev->bdev)
746                         continue;
747
748                 if (one_device && one_device != dev)
749                         continue;
750
751                 disk = dev->bdev->bd_part;
752                 disk_kobj = &part_to_dev(disk)->kobj;
753
754                 error = sysfs_create_link(fs_devices->device_dir_kobj,
755                                           disk_kobj, disk_kobj->name);
756                 if (error)
757                         break;
758         }
759
760         return error;
761 }
762
763 /* /sys/fs/btrfs/ entry */
764 static struct kset *btrfs_kset;
765
766 /* /sys/kernel/debug/btrfs */
767 static struct dentry *btrfs_debugfs_root_dentry;
768
769 /* Debugging tunables and exported data */
770 u64 btrfs_debugfs_test;
771
772 /*
773  * Can be called by the device discovery thread.
774  * And parent can be specified for seed device
775  */
776 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
777                                 struct kobject *parent)
778 {
779         int error;
780
781         init_completion(&fs_devs->kobj_unregister);
782         fs_devs->fsid_kobj.kset = btrfs_kset;
783         error = kobject_init_and_add(&fs_devs->fsid_kobj,
784                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
785         return error;
786 }
787
788 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
789 {
790         int error;
791         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
792         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
793
794         btrfs_set_fs_info_ptr(fs_info);
795
796         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
797         if (error)
798                 return error;
799
800         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
801         if (error) {
802                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
803                 return error;
804         }
805
806         error = sysfs_create_group(fsid_kobj,
807                                    &btrfs_feature_attr_group);
808         if (error)
809                 goto failure;
810
811         error = addrm_unknown_feature_attrs(fs_info, true);
812         if (error)
813                 goto failure;
814
815         fs_info->space_info_kobj = kobject_create_and_add("allocation",
816                                                   fsid_kobj);
817         if (!fs_info->space_info_kobj) {
818                 error = -ENOMEM;
819                 goto failure;
820         }
821
822         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
823         if (error)
824                 goto failure;
825
826         return 0;
827 failure:
828         btrfs_sysfs_remove_mounted(fs_info);
829         return error;
830 }
831
832
833 /*
834  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
835  * values in superblock. Call after any changes to incompat/compat_ro flags
836  */
837 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
838                 u64 bit, enum btrfs_feature_set set)
839 {
840         struct btrfs_fs_devices *fs_devs;
841         struct kobject *fsid_kobj;
842         u64 features;
843         int ret;
844
845         if (!fs_info)
846                 return;
847
848         features = get_features(fs_info, set);
849         ASSERT(bit & supported_feature_masks[set]);
850
851         fs_devs = fs_info->fs_devices;
852         fsid_kobj = &fs_devs->fsid_kobj;
853
854         if (!fsid_kobj->state_initialized)
855                 return;
856
857         /*
858          * FIXME: this is too heavy to update just one value, ideally we'd like
859          * to use sysfs_update_group but some refactoring is needed first.
860          */
861         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
862         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
863 }
864
865 static int btrfs_init_debugfs(void)
866 {
867 #ifdef CONFIG_DEBUG_FS
868         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
869         if (!btrfs_debugfs_root_dentry)
870                 return -ENOMEM;
871
872         /*
873          * Example code, how to export data through debugfs.
874          *
875          * file:        /sys/kernel/debug/btrfs/test
876          * contents of: btrfs_debugfs_test
877          */
878 #ifdef CONFIG_BTRFS_DEBUG
879         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
880                         &btrfs_debugfs_test);
881 #endif
882
883 #endif
884         return 0;
885 }
886
887 int __init btrfs_init_sysfs(void)
888 {
889         int ret;
890
891         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
892         if (!btrfs_kset)
893                 return -ENOMEM;
894
895         ret = btrfs_init_debugfs();
896         if (ret)
897                 goto out1;
898
899         init_feature_attrs();
900         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
901         if (ret)
902                 goto out2;
903
904         return 0;
905 out2:
906         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
907 out1:
908         kset_unregister(btrfs_kset);
909
910         return ret;
911 }
912
913 void __cold btrfs_exit_sysfs(void)
914 {
915         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
916         kset_unregister(btrfs_kset);
917         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
918 }
919