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TOMOYO Linux Cross Reference
Linux/fs/btrfs/sysfs.c

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  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/kobject.h>
 11 #include <linux/bug.h>
 12 #include <linux/debugfs.h>
 13 
 14 #include "ctree.h"
 15 #include "disk-io.h"
 16 #include "transaction.h"
 17 #include "sysfs.h"
 18 #include "volumes.h"
 19 
 20 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
 21 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
 22 
 23 static u64 get_features(struct btrfs_fs_info *fs_info,
 24                         enum btrfs_feature_set set)
 25 {
 26         struct btrfs_super_block *disk_super = fs_info->super_copy;
 27         if (set == FEAT_COMPAT)
 28                 return btrfs_super_compat_flags(disk_super);
 29         else if (set == FEAT_COMPAT_RO)
 30                 return btrfs_super_compat_ro_flags(disk_super);
 31         else
 32                 return btrfs_super_incompat_flags(disk_super);
 33 }
 34 
 35 static void set_features(struct btrfs_fs_info *fs_info,
 36                          enum btrfs_feature_set set, u64 features)
 37 {
 38         struct btrfs_super_block *disk_super = fs_info->super_copy;
 39         if (set == FEAT_COMPAT)
 40                 btrfs_set_super_compat_flags(disk_super, features);
 41         else if (set == FEAT_COMPAT_RO)
 42                 btrfs_set_super_compat_ro_flags(disk_super, features);
 43         else
 44                 btrfs_set_super_incompat_flags(disk_super, features);
 45 }
 46 
 47 static int can_modify_feature(struct btrfs_feature_attr *fa)
 48 {
 49         int val = 0;
 50         u64 set, clear;
 51         switch (fa->feature_set) {
 52         case FEAT_COMPAT:
 53                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 54                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 55                 break;
 56         case FEAT_COMPAT_RO:
 57                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 58                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 59                 break;
 60         case FEAT_INCOMPAT:
 61                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 62                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 63                 break;
 64         default:
 65                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
 66                                 fa->feature_set);
 67                 return 0;
 68         }
 69 
 70         if (set & fa->feature_bit)
 71                 val |= 1;
 72         if (clear & fa->feature_bit)
 73                 val |= 2;
 74 
 75         return val;
 76 }
 77 
 78 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
 79                                        struct kobj_attribute *a, char *buf)
 80 {
 81         int val = 0;
 82         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 83         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 84         if (fs_info) {
 85                 u64 features = get_features(fs_info, fa->feature_set);
 86                 if (features & fa->feature_bit)
 87                         val = 1;
 88         } else
 89                 val = can_modify_feature(fa);
 90 
 91         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 92 }
 93 
 94 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 95                                         struct kobj_attribute *a,
 96                                         const char *buf, size_t count)
 97 {
 98         struct btrfs_fs_info *fs_info;
 99         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
100         u64 features, set, clear;
101         unsigned long val;
102         int ret;
103 
104         fs_info = to_fs_info(kobj);
105         if (!fs_info)
106                 return -EPERM;
107 
108         if (sb_rdonly(fs_info->sb))
109                 return -EROFS;
110 
111         ret = kstrtoul(skip_spaces(buf), 0, &val);
112         if (ret)
113                 return ret;
114 
115         if (fa->feature_set == FEAT_COMPAT) {
116                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
117                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
118         } else if (fa->feature_set == FEAT_COMPAT_RO) {
119                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
120                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
121         } else {
122                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
123                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
124         }
125 
126         features = get_features(fs_info, fa->feature_set);
127 
128         /* Nothing to do */
129         if ((val && (features & fa->feature_bit)) ||
130             (!val && !(features & fa->feature_bit)))
131                 return count;
132 
133         if ((val && !(set & fa->feature_bit)) ||
134             (!val && !(clear & fa->feature_bit))) {
135                 btrfs_info(fs_info,
136                         "%sabling feature %s on mounted fs is not supported.",
137                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
138                 return -EPERM;
139         }
140 
141         btrfs_info(fs_info, "%s %s feature flag",
142                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
143 
144         spin_lock(&fs_info->super_lock);
145         features = get_features(fs_info, fa->feature_set);
146         if (val)
147                 features |= fa->feature_bit;
148         else
149                 features &= ~fa->feature_bit;
150         set_features(fs_info, fa->feature_set, features);
151         spin_unlock(&fs_info->super_lock);
152 
153         /*
154          * We don't want to do full transaction commit from inside sysfs
155          */
156         btrfs_set_pending(fs_info, COMMIT);
157         wake_up_process(fs_info->transaction_kthread);
158 
159         return count;
160 }
161 
162 static umode_t btrfs_feature_visible(struct kobject *kobj,
163                                      struct attribute *attr, int unused)
164 {
165         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
166         umode_t mode = attr->mode;
167 
168         if (fs_info) {
169                 struct btrfs_feature_attr *fa;
170                 u64 features;
171 
172                 fa = attr_to_btrfs_feature_attr(attr);
173                 features = get_features(fs_info, fa->feature_set);
174 
175                 if (can_modify_feature(fa))
176                         mode |= S_IWUSR;
177                 else if (!(features & fa->feature_bit))
178                         mode = 0;
179         }
180 
181         return mode;
182 }
183 
184 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
185 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
186 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
187 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
188 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
189 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
190 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
191 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
192 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
193 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
194 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
195 
196 static struct attribute *btrfs_supported_feature_attrs[] = {
197         BTRFS_FEAT_ATTR_PTR(mixed_backref),
198         BTRFS_FEAT_ATTR_PTR(default_subvol),
199         BTRFS_FEAT_ATTR_PTR(mixed_groups),
200         BTRFS_FEAT_ATTR_PTR(compress_lzo),
201         BTRFS_FEAT_ATTR_PTR(compress_zstd),
202         BTRFS_FEAT_ATTR_PTR(big_metadata),
203         BTRFS_FEAT_ATTR_PTR(extended_iref),
204         BTRFS_FEAT_ATTR_PTR(raid56),
205         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
206         BTRFS_FEAT_ATTR_PTR(no_holes),
207         BTRFS_FEAT_ATTR_PTR(free_space_tree),
208         NULL
209 };
210 
211 /*
212  * Features which depend on feature bits and may differ between each fs.
213  *
214  * /sys/fs/btrfs/features lists all available features of this kernel while
215  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
216  * can be changed online.
217  */
218 static const struct attribute_group btrfs_feature_attr_group = {
219         .name = "features",
220         .is_visible = btrfs_feature_visible,
221         .attrs = btrfs_supported_feature_attrs,
222 };
223 
224 static ssize_t rmdir_subvol_show(struct kobject *kobj,
225                                  struct kobj_attribute *ka, char *buf)
226 {
227         return snprintf(buf, PAGE_SIZE, "\n");
228 }
229 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
230 
231 static struct attribute *btrfs_supported_static_feature_attrs[] = {
232         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
233         NULL
234 };
235 
236 /*
237  * Features which only depend on kernel version.
238  *
239  * These are listed in /sys/fs/btrfs/features along with
240  * btrfs_feature_attr_group
241  */
242 static const struct attribute_group btrfs_static_feature_attr_group = {
243         .name = "features",
244         .attrs = btrfs_supported_static_feature_attrs,
245 };
246 
247 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
248 {
249         u64 val;
250         if (lock)
251                 spin_lock(lock);
252         val = *value_ptr;
253         if (lock)
254                 spin_unlock(lock);
255         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
256 }
257 
258 static ssize_t global_rsv_size_show(struct kobject *kobj,
259                                     struct kobj_attribute *ka, char *buf)
260 {
261         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
262         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
263         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
264 }
265 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
266 
267 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
268                                         struct kobj_attribute *a, char *buf)
269 {
270         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
271         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
272         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
273 }
274 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
275 
276 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
277 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
278 
279 static ssize_t raid_bytes_show(struct kobject *kobj,
280                                struct kobj_attribute *attr, char *buf);
281 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
282 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
283 
284 static ssize_t raid_bytes_show(struct kobject *kobj,
285                                struct kobj_attribute *attr, char *buf)
286 
287 {
288         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
289         struct btrfs_block_group_cache *block_group;
290         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
291         u64 val = 0;
292 
293         down_read(&sinfo->groups_sem);
294         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
295                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
296                         val += block_group->key.offset;
297                 else
298                         val += btrfs_block_group_used(&block_group->item);
299         }
300         up_read(&sinfo->groups_sem);
301         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
302 }
303 
304 static struct attribute *raid_attributes[] = {
305         BTRFS_ATTR_PTR(raid, total_bytes),
306         BTRFS_ATTR_PTR(raid, used_bytes),
307         NULL
308 };
309 
310 static void release_raid_kobj(struct kobject *kobj)
311 {
312         kfree(to_raid_kobj(kobj));
313 }
314 
315 struct kobj_type btrfs_raid_ktype = {
316         .sysfs_ops = &kobj_sysfs_ops,
317         .release = release_raid_kobj,
318         .default_attrs = raid_attributes,
319 };
320 
321 #define SPACE_INFO_ATTR(field)                                          \
322 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
323                                              struct kobj_attribute *a,  \
324                                              char *buf)                 \
325 {                                                                       \
326         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
327         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
328 }                                                                       \
329 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
330 
331 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
332                                                        struct kobj_attribute *a,
333                                                        char *buf)
334 {
335         struct btrfs_space_info *sinfo = to_space_info(kobj);
336         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
337         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
338 }
339 
340 SPACE_INFO_ATTR(flags);
341 SPACE_INFO_ATTR(total_bytes);
342 SPACE_INFO_ATTR(bytes_used);
343 SPACE_INFO_ATTR(bytes_pinned);
344 SPACE_INFO_ATTR(bytes_reserved);
345 SPACE_INFO_ATTR(bytes_may_use);
346 SPACE_INFO_ATTR(bytes_readonly);
347 SPACE_INFO_ATTR(disk_used);
348 SPACE_INFO_ATTR(disk_total);
349 BTRFS_ATTR(space_info, total_bytes_pinned,
350            btrfs_space_info_show_total_bytes_pinned);
351 
352 static struct attribute *space_info_attrs[] = {
353         BTRFS_ATTR_PTR(space_info, flags),
354         BTRFS_ATTR_PTR(space_info, total_bytes),
355         BTRFS_ATTR_PTR(space_info, bytes_used),
356         BTRFS_ATTR_PTR(space_info, bytes_pinned),
357         BTRFS_ATTR_PTR(space_info, bytes_reserved),
358         BTRFS_ATTR_PTR(space_info, bytes_may_use),
359         BTRFS_ATTR_PTR(space_info, bytes_readonly),
360         BTRFS_ATTR_PTR(space_info, disk_used),
361         BTRFS_ATTR_PTR(space_info, disk_total),
362         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
363         NULL,
364 };
365 
366 static void space_info_release(struct kobject *kobj)
367 {
368         struct btrfs_space_info *sinfo = to_space_info(kobj);
369         percpu_counter_destroy(&sinfo->total_bytes_pinned);
370         kfree(sinfo);
371 }
372 
373 struct kobj_type space_info_ktype = {
374         .sysfs_ops = &kobj_sysfs_ops,
375         .release = space_info_release,
376         .default_attrs = space_info_attrs,
377 };
378 
379 static const struct attribute *allocation_attrs[] = {
380         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
381         BTRFS_ATTR_PTR(allocation, global_rsv_size),
382         NULL,
383 };
384 
385 static ssize_t btrfs_label_show(struct kobject *kobj,
386                                 struct kobj_attribute *a, char *buf)
387 {
388         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
389         char *label = fs_info->super_copy->label;
390         ssize_t ret;
391 
392         spin_lock(&fs_info->super_lock);
393         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
394         spin_unlock(&fs_info->super_lock);
395 
396         return ret;
397 }
398 
399 static ssize_t btrfs_label_store(struct kobject *kobj,
400                                  struct kobj_attribute *a,
401                                  const char *buf, size_t len)
402 {
403         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
404         size_t p_len;
405 
406         if (!fs_info)
407                 return -EPERM;
408 
409         if (sb_rdonly(fs_info->sb))
410                 return -EROFS;
411 
412         /*
413          * p_len is the len until the first occurrence of either
414          * '\n' or '\0'
415          */
416         p_len = strcspn(buf, "\n");
417 
418         if (p_len >= BTRFS_LABEL_SIZE)
419                 return -EINVAL;
420 
421         spin_lock(&fs_info->super_lock);
422         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
423         memcpy(fs_info->super_copy->label, buf, p_len);
424         spin_unlock(&fs_info->super_lock);
425 
426         /*
427          * We don't want to do full transaction commit from inside sysfs
428          */
429         btrfs_set_pending(fs_info, COMMIT);
430         wake_up_process(fs_info->transaction_kthread);
431 
432         return len;
433 }
434 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
435 
436 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
437                                 struct kobj_attribute *a, char *buf)
438 {
439         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
440 
441         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
442 }
443 
444 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
445 
446 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
447                                 struct kobj_attribute *a, char *buf)
448 {
449         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
450 
451         return snprintf(buf, PAGE_SIZE, "%u\n",
452                         fs_info->super_copy->sectorsize);
453 }
454 
455 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
456 
457 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
458                                 struct kobj_attribute *a, char *buf)
459 {
460         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
461 
462         return snprintf(buf, PAGE_SIZE, "%u\n",
463                         fs_info->super_copy->sectorsize);
464 }
465 
466 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
467 
468 static ssize_t quota_override_show(struct kobject *kobj,
469                                    struct kobj_attribute *a, char *buf)
470 {
471         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
472         int quota_override;
473 
474         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
475         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
476 }
477 
478 static ssize_t quota_override_store(struct kobject *kobj,
479                                     struct kobj_attribute *a,
480                                     const char *buf, size_t len)
481 {
482         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
483         unsigned long knob;
484         int err;
485 
486         if (!fs_info)
487                 return -EPERM;
488 
489         if (!capable(CAP_SYS_RESOURCE))
490                 return -EPERM;
491 
492         err = kstrtoul(buf, 10, &knob);
493         if (err)
494                 return err;
495         if (knob > 1)
496                 return -EINVAL;
497 
498         if (knob)
499                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
500         else
501                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
502 
503         return len;
504 }
505 
506 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
507 
508 static const struct attribute *btrfs_attrs[] = {
509         BTRFS_ATTR_PTR(, label),
510         BTRFS_ATTR_PTR(, nodesize),
511         BTRFS_ATTR_PTR(, sectorsize),
512         BTRFS_ATTR_PTR(, clone_alignment),
513         BTRFS_ATTR_PTR(, quota_override),
514         NULL,
515 };
516 
517 static void btrfs_release_fsid_kobj(struct kobject *kobj)
518 {
519         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
520 
521         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
522         complete(&fs_devs->kobj_unregister);
523 }
524 
525 static struct kobj_type btrfs_ktype = {
526         .sysfs_ops      = &kobj_sysfs_ops,
527         .release        = btrfs_release_fsid_kobj,
528 };
529 
530 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
531 {
532         if (kobj->ktype != &btrfs_ktype)
533                 return NULL;
534         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
535 }
536 
537 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
538 {
539         if (kobj->ktype != &btrfs_ktype)
540                 return NULL;
541         return to_fs_devs(kobj)->fs_info;
542 }
543 
544 #define NUM_FEATURE_BITS 64
545 #define BTRFS_FEATURE_NAME_MAX 13
546 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
547 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
548 
549 static const u64 supported_feature_masks[FEAT_MAX] = {
550         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
551         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
552         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
553 };
554 
555 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
556 {
557         int set;
558 
559         for (set = 0; set < FEAT_MAX; set++) {
560                 int i;
561                 struct attribute *attrs[2];
562                 struct attribute_group agroup = {
563                         .name = "features",
564                         .attrs = attrs,
565                 };
566                 u64 features = get_features(fs_info, set);
567                 features &= ~supported_feature_masks[set];
568 
569                 if (!features)
570                         continue;
571 
572                 attrs[1] = NULL;
573                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
574                         struct btrfs_feature_attr *fa;
575 
576                         if (!(features & (1ULL << i)))
577                                 continue;
578 
579                         fa = &btrfs_feature_attrs[set][i];
580                         attrs[0] = &fa->kobj_attr.attr;
581                         if (add) {
582                                 int ret;
583                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
584                                                         &agroup);
585                                 if (ret)
586                                         return ret;
587                         } else
588                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
589                                                     &agroup);
590                 }
591 
592         }
593         return 0;
594 }
595 
596 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
597 {
598         if (fs_devs->device_dir_kobj) {
599                 kobject_del(fs_devs->device_dir_kobj);
600                 kobject_put(fs_devs->device_dir_kobj);
601                 fs_devs->device_dir_kobj = NULL;
602         }
603 
604         if (fs_devs->fsid_kobj.state_initialized) {
605                 kobject_del(&fs_devs->fsid_kobj);
606                 kobject_put(&fs_devs->fsid_kobj);
607                 wait_for_completion(&fs_devs->kobj_unregister);
608         }
609 }
610 
611 /* when fs_devs is NULL it will remove all fsid kobject */
612 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
613 {
614         struct list_head *fs_uuids = btrfs_get_fs_uuids();
615 
616         if (fs_devs) {
617                 __btrfs_sysfs_remove_fsid(fs_devs);
618                 return;
619         }
620 
621         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
622                 __btrfs_sysfs_remove_fsid(fs_devs);
623         }
624 }
625 
626 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
627 {
628         btrfs_reset_fs_info_ptr(fs_info);
629 
630         if (fs_info->space_info_kobj) {
631                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
632                 kobject_del(fs_info->space_info_kobj);
633                 kobject_put(fs_info->space_info_kobj);
634         }
635         addrm_unknown_feature_attrs(fs_info, false);
636         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
637         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
638         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
639 }
640 
641 const char * const btrfs_feature_set_names[FEAT_MAX] = {
642         [FEAT_COMPAT]    = "compat",
643         [FEAT_COMPAT_RO] = "compat_ro",
644         [FEAT_INCOMPAT]  = "incompat",
645 };
646 
647 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
648 {
649         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
650         int len = 0;
651         int i;
652         char *str;
653 
654         str = kmalloc(bufsize, GFP_KERNEL);
655         if (!str)
656                 return str;
657 
658         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
659                 const char *name;
660 
661                 if (!(flags & (1ULL << i)))
662                         continue;
663 
664                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
665                 len += snprintf(str + len, bufsize - len, "%s%s",
666                                 len ? "," : "", name);
667         }
668 
669         return str;
670 }
671 
672 static void init_feature_attrs(void)
673 {
674         struct btrfs_feature_attr *fa;
675         int set, i;
676 
677         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
678                      ARRAY_SIZE(btrfs_feature_attrs));
679         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
680                      ARRAY_SIZE(btrfs_feature_attrs[0]));
681 
682         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
683         memset(btrfs_unknown_feature_names, 0,
684                sizeof(btrfs_unknown_feature_names));
685 
686         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
687                 struct btrfs_feature_attr *sfa;
688                 struct attribute *a = btrfs_supported_feature_attrs[i];
689                 int bit;
690                 sfa = attr_to_btrfs_feature_attr(a);
691                 bit = ilog2(sfa->feature_bit);
692                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
693 
694                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
695         }
696 
697         for (set = 0; set < FEAT_MAX; set++) {
698                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
699                         char *name = btrfs_unknown_feature_names[set][i];
700                         fa = &btrfs_feature_attrs[set][i];
701 
702                         if (fa->kobj_attr.attr.name)
703                                 continue;
704 
705                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
706                                  btrfs_feature_set_names[set], i);
707 
708                         fa->kobj_attr.attr.name = name;
709                         fa->kobj_attr.attr.mode = S_IRUGO;
710                         fa->feature_set = set;
711                         fa->feature_bit = 1ULL << i;
712                 }
713         }
714 }
715 
716 /* when one_device is NULL, it removes all device links */
717 
718 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
719                 struct btrfs_device *one_device)
720 {
721         struct hd_struct *disk;
722         struct kobject *disk_kobj;
723 
724         if (!fs_devices->device_dir_kobj)
725                 return -EINVAL;
726 
727         if (one_device && one_device->bdev) {
728                 disk = one_device->bdev->bd_part;
729                 disk_kobj = &part_to_dev(disk)->kobj;
730 
731                 sysfs_remove_link(fs_devices->device_dir_kobj,
732                                                 disk_kobj->name);
733         }
734 
735         if (one_device)
736                 return 0;
737 
738         list_for_each_entry(one_device,
739                         &fs_devices->devices, dev_list) {
740                 if (!one_device->bdev)
741                         continue;
742                 disk = one_device->bdev->bd_part;
743                 disk_kobj = &part_to_dev(disk)->kobj;
744 
745                 sysfs_remove_link(fs_devices->device_dir_kobj,
746                                                 disk_kobj->name);
747         }
748 
749         return 0;
750 }
751 
752 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
753 {
754         if (!fs_devs->device_dir_kobj)
755                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
756                                                 &fs_devs->fsid_kobj);
757 
758         if (!fs_devs->device_dir_kobj)
759                 return -ENOMEM;
760 
761         return 0;
762 }
763 
764 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
765                                 struct btrfs_device *one_device)
766 {
767         int error = 0;
768         struct btrfs_device *dev;
769 
770         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
771                 struct hd_struct *disk;
772                 struct kobject *disk_kobj;
773 
774                 if (!dev->bdev)
775                         continue;
776 
777                 if (one_device && one_device != dev)
778                         continue;
779 
780                 disk = dev->bdev->bd_part;
781                 disk_kobj = &part_to_dev(disk)->kobj;
782 
783                 error = sysfs_create_link(fs_devices->device_dir_kobj,
784                                           disk_kobj, disk_kobj->name);
785                 if (error)
786                         break;
787         }
788 
789         return error;
790 }
791 
792 /* /sys/fs/btrfs/ entry */
793 static struct kset *btrfs_kset;
794 
795 /* /sys/kernel/debug/btrfs */
796 static struct dentry *btrfs_debugfs_root_dentry;
797 
798 /* Debugging tunables and exported data */
799 u64 btrfs_debugfs_test;
800 
801 /*
802  * Can be called by the device discovery thread.
803  * And parent can be specified for seed device
804  */
805 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
806                                 struct kobject *parent)
807 {
808         int error;
809 
810         init_completion(&fs_devs->kobj_unregister);
811         fs_devs->fsid_kobj.kset = btrfs_kset;
812         error = kobject_init_and_add(&fs_devs->fsid_kobj,
813                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
814         return error;
815 }
816 
817 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
818 {
819         int error;
820         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
821         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
822 
823         btrfs_set_fs_info_ptr(fs_info);
824 
825         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
826         if (error)
827                 return error;
828 
829         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
830         if (error) {
831                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
832                 return error;
833         }
834 
835         error = sysfs_create_group(fsid_kobj,
836                                    &btrfs_feature_attr_group);
837         if (error)
838                 goto failure;
839 
840         error = addrm_unknown_feature_attrs(fs_info, true);
841         if (error)
842                 goto failure;
843 
844         fs_info->space_info_kobj = kobject_create_and_add("allocation",
845                                                   fsid_kobj);
846         if (!fs_info->space_info_kobj) {
847                 error = -ENOMEM;
848                 goto failure;
849         }
850 
851         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
852         if (error)
853                 goto failure;
854 
855         return 0;
856 failure:
857         btrfs_sysfs_remove_mounted(fs_info);
858         return error;
859 }
860 
861 
862 /*
863  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
864  * values in superblock. Call after any changes to incompat/compat_ro flags
865  */
866 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
867                 u64 bit, enum btrfs_feature_set set)
868 {
869         struct btrfs_fs_devices *fs_devs;
870         struct kobject *fsid_kobj;
871         u64 features;
872         int ret;
873 
874         if (!fs_info)
875                 return;
876 
877         features = get_features(fs_info, set);
878         ASSERT(bit & supported_feature_masks[set]);
879 
880         fs_devs = fs_info->fs_devices;
881         fsid_kobj = &fs_devs->fsid_kobj;
882 
883         if (!fsid_kobj->state_initialized)
884                 return;
885 
886         /*
887          * FIXME: this is too heavy to update just one value, ideally we'd like
888          * to use sysfs_update_group but some refactoring is needed first.
889          */
890         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
891         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
892 }
893 
894 static int btrfs_init_debugfs(void)
895 {
896 #ifdef CONFIG_DEBUG_FS
897         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
898         if (!btrfs_debugfs_root_dentry)
899                 return -ENOMEM;
900 
901         /*
902          * Example code, how to export data through debugfs.
903          *
904          * file:        /sys/kernel/debug/btrfs/test
905          * contents of: btrfs_debugfs_test
906          */
907 #ifdef CONFIG_BTRFS_DEBUG
908         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
909                         &btrfs_debugfs_test);
910 #endif
911 
912 #endif
913         return 0;
914 }
915 
916 int __init btrfs_init_sysfs(void)
917 {
918         int ret;
919 
920         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
921         if (!btrfs_kset)
922                 return -ENOMEM;
923 
924         ret = btrfs_init_debugfs();
925         if (ret)
926                 goto out1;
927 
928         init_feature_attrs();
929         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
930         if (ret)
931                 goto out2;
932         ret = sysfs_merge_group(&btrfs_kset->kobj,
933                                 &btrfs_static_feature_attr_group);
934         if (ret)
935                 goto out_remove_group;
936 
937         return 0;
938 
939 out_remove_group:
940         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
941 out2:
942         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
943 out1:
944         kset_unregister(btrfs_kset);
945 
946         return ret;
947 }
948 
949 void __cold btrfs_exit_sysfs(void)
950 {
951         sysfs_unmerge_group(&btrfs_kset->kobj,
952                             &btrfs_static_feature_attr_group);
953         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
954         kset_unregister(btrfs_kset);
955         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
956 }
957 
958 

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