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

Version: ~ [ linux-5.5-rc7 ] ~ [ linux-5.4.13 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.97 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.166 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.210 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.210 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.81 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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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/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 /*
214  * Features which depend on feature bits and may differ between each fs.
215  *
216  * /sys/fs/btrfs/features lists all available features of this kernel while
217  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
218  * can be changed online.
219  */
220 static const struct attribute_group btrfs_feature_attr_group = {
221         .name = "features",
222         .is_visible = btrfs_feature_visible,
223         .attrs = btrfs_supported_feature_attrs,
224 };
225 
226 static ssize_t rmdir_subvol_show(struct kobject *kobj,
227                                  struct kobj_attribute *ka, char *buf)
228 {
229         return snprintf(buf, PAGE_SIZE, "\n");
230 }
231 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
232 
233 static struct attribute *btrfs_supported_static_feature_attrs[] = {
234         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
235         NULL
236 };
237 
238 /*
239  * Features which only depend on kernel version.
240  *
241  * These are listed in /sys/fs/btrfs/features along with
242  * btrfs_feature_attr_group
243  */
244 static const struct attribute_group btrfs_static_feature_attr_group = {
245         .name = "features",
246         .attrs = btrfs_supported_static_feature_attrs,
247 };
248 
249 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
250 {
251         u64 val;
252         if (lock)
253                 spin_lock(lock);
254         val = *value_ptr;
255         if (lock)
256                 spin_unlock(lock);
257         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
258 }
259 
260 static ssize_t global_rsv_size_show(struct kobject *kobj,
261                                     struct kobj_attribute *ka, char *buf)
262 {
263         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
264         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
265         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
266 }
267 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
268 
269 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
270                                         struct kobj_attribute *a, char *buf)
271 {
272         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
273         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
274         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
275 }
276 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
277 
278 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
279 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
280 
281 static ssize_t raid_bytes_show(struct kobject *kobj,
282                                struct kobj_attribute *attr, char *buf);
283 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
284 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
285 
286 static ssize_t raid_bytes_show(struct kobject *kobj,
287                                struct kobj_attribute *attr, char *buf)
288 
289 {
290         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
291         struct btrfs_block_group_cache *block_group;
292         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
293         u64 val = 0;
294 
295         down_read(&sinfo->groups_sem);
296         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
297                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
298                         val += block_group->key.offset;
299                 else
300                         val += btrfs_block_group_used(&block_group->item);
301         }
302         up_read(&sinfo->groups_sem);
303         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
304 }
305 
306 static struct attribute *raid_attributes[] = {
307         BTRFS_ATTR_PTR(raid, total_bytes),
308         BTRFS_ATTR_PTR(raid, used_bytes),
309         NULL
310 };
311 
312 static void release_raid_kobj(struct kobject *kobj)
313 {
314         kfree(to_raid_kobj(kobj));
315 }
316 
317 struct kobj_type btrfs_raid_ktype = {
318         .sysfs_ops = &kobj_sysfs_ops,
319         .release = release_raid_kobj,
320         .default_attrs = raid_attributes,
321 };
322 
323 #define SPACE_INFO_ATTR(field)                                          \
324 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
325                                              struct kobj_attribute *a,  \
326                                              char *buf)                 \
327 {                                                                       \
328         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
329         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
330 }                                                                       \
331 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
332 
333 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
334                                                        struct kobj_attribute *a,
335                                                        char *buf)
336 {
337         struct btrfs_space_info *sinfo = to_space_info(kobj);
338         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
339         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
340 }
341 
342 SPACE_INFO_ATTR(flags);
343 SPACE_INFO_ATTR(total_bytes);
344 SPACE_INFO_ATTR(bytes_used);
345 SPACE_INFO_ATTR(bytes_pinned);
346 SPACE_INFO_ATTR(bytes_reserved);
347 SPACE_INFO_ATTR(bytes_may_use);
348 SPACE_INFO_ATTR(bytes_readonly);
349 SPACE_INFO_ATTR(disk_used);
350 SPACE_INFO_ATTR(disk_total);
351 BTRFS_ATTR(space_info, total_bytes_pinned,
352            btrfs_space_info_show_total_bytes_pinned);
353 
354 static struct attribute *space_info_attrs[] = {
355         BTRFS_ATTR_PTR(space_info, flags),
356         BTRFS_ATTR_PTR(space_info, total_bytes),
357         BTRFS_ATTR_PTR(space_info, bytes_used),
358         BTRFS_ATTR_PTR(space_info, bytes_pinned),
359         BTRFS_ATTR_PTR(space_info, bytes_reserved),
360         BTRFS_ATTR_PTR(space_info, bytes_may_use),
361         BTRFS_ATTR_PTR(space_info, bytes_readonly),
362         BTRFS_ATTR_PTR(space_info, disk_used),
363         BTRFS_ATTR_PTR(space_info, disk_total),
364         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
365         NULL,
366 };
367 
368 static void space_info_release(struct kobject *kobj)
369 {
370         struct btrfs_space_info *sinfo = to_space_info(kobj);
371         percpu_counter_destroy(&sinfo->total_bytes_pinned);
372         kfree(sinfo);
373 }
374 
375 struct kobj_type space_info_ktype = {
376         .sysfs_ops = &kobj_sysfs_ops,
377         .release = space_info_release,
378         .default_attrs = space_info_attrs,
379 };
380 
381 static const struct attribute *allocation_attrs[] = {
382         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
383         BTRFS_ATTR_PTR(allocation, global_rsv_size),
384         NULL,
385 };
386 
387 static ssize_t btrfs_label_show(struct kobject *kobj,
388                                 struct kobj_attribute *a, char *buf)
389 {
390         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
391         char *label = fs_info->super_copy->label;
392         ssize_t ret;
393 
394         spin_lock(&fs_info->super_lock);
395         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
396         spin_unlock(&fs_info->super_lock);
397 
398         return ret;
399 }
400 
401 static ssize_t btrfs_label_store(struct kobject *kobj,
402                                  struct kobj_attribute *a,
403                                  const char *buf, size_t len)
404 {
405         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
406         size_t p_len;
407 
408         if (!fs_info)
409                 return -EPERM;
410 
411         if (sb_rdonly(fs_info->sb))
412                 return -EROFS;
413 
414         /*
415          * p_len is the len until the first occurrence of either
416          * '\n' or '\0'
417          */
418         p_len = strcspn(buf, "\n");
419 
420         if (p_len >= BTRFS_LABEL_SIZE)
421                 return -EINVAL;
422 
423         spin_lock(&fs_info->super_lock);
424         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
425         memcpy(fs_info->super_copy->label, buf, p_len);
426         spin_unlock(&fs_info->super_lock);
427 
428         /*
429          * We don't want to do full transaction commit from inside sysfs
430          */
431         btrfs_set_pending(fs_info, COMMIT);
432         wake_up_process(fs_info->transaction_kthread);
433 
434         return len;
435 }
436 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
437 
438 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
439                                 struct kobj_attribute *a, char *buf)
440 {
441         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
442 
443         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
444 }
445 
446 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
447 
448 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
449                                 struct kobj_attribute *a, char *buf)
450 {
451         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
452 
453         return snprintf(buf, PAGE_SIZE, "%u\n",
454                         fs_info->super_copy->sectorsize);
455 }
456 
457 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
458 
459 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
460                                 struct kobj_attribute *a, char *buf)
461 {
462         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
463 
464         return snprintf(buf, PAGE_SIZE, "%u\n",
465                         fs_info->super_copy->sectorsize);
466 }
467 
468 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
469 
470 static ssize_t quota_override_show(struct kobject *kobj,
471                                    struct kobj_attribute *a, char *buf)
472 {
473         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
474         int quota_override;
475 
476         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
477         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
478 }
479 
480 static ssize_t quota_override_store(struct kobject *kobj,
481                                     struct kobj_attribute *a,
482                                     const char *buf, size_t len)
483 {
484         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
485         unsigned long knob;
486         int err;
487 
488         if (!fs_info)
489                 return -EPERM;
490 
491         if (!capable(CAP_SYS_RESOURCE))
492                 return -EPERM;
493 
494         err = kstrtoul(buf, 10, &knob);
495         if (err)
496                 return err;
497         if (knob > 1)
498                 return -EINVAL;
499 
500         if (knob)
501                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
502         else
503                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
504 
505         return len;
506 }
507 
508 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
509 
510 static const struct attribute *btrfs_attrs[] = {
511         BTRFS_ATTR_PTR(, label),
512         BTRFS_ATTR_PTR(, nodesize),
513         BTRFS_ATTR_PTR(, sectorsize),
514         BTRFS_ATTR_PTR(, clone_alignment),
515         BTRFS_ATTR_PTR(, quota_override),
516         NULL,
517 };
518 
519 static void btrfs_release_fsid_kobj(struct kobject *kobj)
520 {
521         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
522 
523         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
524         complete(&fs_devs->kobj_unregister);
525 }
526 
527 static struct kobj_type btrfs_ktype = {
528         .sysfs_ops      = &kobj_sysfs_ops,
529         .release        = btrfs_release_fsid_kobj,
530 };
531 
532 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
533 {
534         if (kobj->ktype != &btrfs_ktype)
535                 return NULL;
536         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
537 }
538 
539 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
540 {
541         if (kobj->ktype != &btrfs_ktype)
542                 return NULL;
543         return to_fs_devs(kobj)->fs_info;
544 }
545 
546 #define NUM_FEATURE_BITS 64
547 #define BTRFS_FEATURE_NAME_MAX 13
548 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
549 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
550 
551 static const u64 supported_feature_masks[FEAT_MAX] = {
552         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
553         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
554         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
555 };
556 
557 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
558 {
559         int set;
560 
561         for (set = 0; set < FEAT_MAX; set++) {
562                 int i;
563                 struct attribute *attrs[2];
564                 struct attribute_group agroup = {
565                         .name = "features",
566                         .attrs = attrs,
567                 };
568                 u64 features = get_features(fs_info, set);
569                 features &= ~supported_feature_masks[set];
570 
571                 if (!features)
572                         continue;
573 
574                 attrs[1] = NULL;
575                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
576                         struct btrfs_feature_attr *fa;
577 
578                         if (!(features & (1ULL << i)))
579                                 continue;
580 
581                         fa = &btrfs_feature_attrs[set][i];
582                         attrs[0] = &fa->kobj_attr.attr;
583                         if (add) {
584                                 int ret;
585                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
586                                                         &agroup);
587                                 if (ret)
588                                         return ret;
589                         } else
590                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
591                                                     &agroup);
592                 }
593 
594         }
595         return 0;
596 }
597 
598 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
599 {
600         if (fs_devs->device_dir_kobj) {
601                 kobject_del(fs_devs->device_dir_kobj);
602                 kobject_put(fs_devs->device_dir_kobj);
603                 fs_devs->device_dir_kobj = NULL;
604         }
605 
606         if (fs_devs->fsid_kobj.state_initialized) {
607                 kobject_del(&fs_devs->fsid_kobj);
608                 kobject_put(&fs_devs->fsid_kobj);
609                 wait_for_completion(&fs_devs->kobj_unregister);
610         }
611 }
612 
613 /* when fs_devs is NULL it will remove all fsid kobject */
614 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
615 {
616         struct list_head *fs_uuids = btrfs_get_fs_uuids();
617 
618         if (fs_devs) {
619                 __btrfs_sysfs_remove_fsid(fs_devs);
620                 return;
621         }
622 
623         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
624                 __btrfs_sysfs_remove_fsid(fs_devs);
625         }
626 }
627 
628 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
629 {
630         btrfs_reset_fs_info_ptr(fs_info);
631 
632         if (fs_info->space_info_kobj) {
633                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
634                 kobject_del(fs_info->space_info_kobj);
635                 kobject_put(fs_info->space_info_kobj);
636         }
637         addrm_unknown_feature_attrs(fs_info, false);
638         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
639         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
640         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
641 }
642 
643 const char * const btrfs_feature_set_names[FEAT_MAX] = {
644         [FEAT_COMPAT]    = "compat",
645         [FEAT_COMPAT_RO] = "compat_ro",
646         [FEAT_INCOMPAT]  = "incompat",
647 };
648 
649 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
650 {
651         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
652         int len = 0;
653         int i;
654         char *str;
655 
656         str = kmalloc(bufsize, GFP_KERNEL);
657         if (!str)
658                 return str;
659 
660         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
661                 const char *name;
662 
663                 if (!(flags & (1ULL << i)))
664                         continue;
665 
666                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
667                 len += snprintf(str + len, bufsize - len, "%s%s",
668                                 len ? "," : "", name);
669         }
670 
671         return str;
672 }
673 
674 static void init_feature_attrs(void)
675 {
676         struct btrfs_feature_attr *fa;
677         int set, i;
678 
679         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
680                      ARRAY_SIZE(btrfs_feature_attrs));
681         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
682                      ARRAY_SIZE(btrfs_feature_attrs[0]));
683 
684         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
685         memset(btrfs_unknown_feature_names, 0,
686                sizeof(btrfs_unknown_feature_names));
687 
688         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
689                 struct btrfs_feature_attr *sfa;
690                 struct attribute *a = btrfs_supported_feature_attrs[i];
691                 int bit;
692                 sfa = attr_to_btrfs_feature_attr(a);
693                 bit = ilog2(sfa->feature_bit);
694                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
695 
696                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
697         }
698 
699         for (set = 0; set < FEAT_MAX; set++) {
700                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
701                         char *name = btrfs_unknown_feature_names[set][i];
702                         fa = &btrfs_feature_attrs[set][i];
703 
704                         if (fa->kobj_attr.attr.name)
705                                 continue;
706 
707                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
708                                  btrfs_feature_set_names[set], i);
709 
710                         fa->kobj_attr.attr.name = name;
711                         fa->kobj_attr.attr.mode = S_IRUGO;
712                         fa->feature_set = set;
713                         fa->feature_bit = 1ULL << i;
714                 }
715         }
716 }
717 
718 /* when one_device is NULL, it removes all device links */
719 
720 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
721                 struct btrfs_device *one_device)
722 {
723         struct hd_struct *disk;
724         struct kobject *disk_kobj;
725 
726         if (!fs_devices->device_dir_kobj)
727                 return -EINVAL;
728 
729         if (one_device && one_device->bdev) {
730                 disk = one_device->bdev->bd_part;
731                 disk_kobj = &part_to_dev(disk)->kobj;
732 
733                 sysfs_remove_link(fs_devices->device_dir_kobj,
734                                                 disk_kobj->name);
735         }
736 
737         if (one_device)
738                 return 0;
739 
740         list_for_each_entry(one_device,
741                         &fs_devices->devices, dev_list) {
742                 if (!one_device->bdev)
743                         continue;
744                 disk = one_device->bdev->bd_part;
745                 disk_kobj = &part_to_dev(disk)->kobj;
746 
747                 sysfs_remove_link(fs_devices->device_dir_kobj,
748                                                 disk_kobj->name);
749         }
750 
751         return 0;
752 }
753 
754 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
755 {
756         if (!fs_devs->device_dir_kobj)
757                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
758                                                 &fs_devs->fsid_kobj);
759 
760         if (!fs_devs->device_dir_kobj)
761                 return -ENOMEM;
762 
763         return 0;
764 }
765 
766 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
767                                 struct btrfs_device *one_device)
768 {
769         int error = 0;
770         struct btrfs_device *dev;
771 
772         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
773                 struct hd_struct *disk;
774                 struct kobject *disk_kobj;
775 
776                 if (!dev->bdev)
777                         continue;
778 
779                 if (one_device && one_device != dev)
780                         continue;
781 
782                 disk = dev->bdev->bd_part;
783                 disk_kobj = &part_to_dev(disk)->kobj;
784 
785                 error = sysfs_create_link(fs_devices->device_dir_kobj,
786                                           disk_kobj, disk_kobj->name);
787                 if (error)
788                         break;
789         }
790 
791         return error;
792 }
793 
794 /* /sys/fs/btrfs/ entry */
795 static struct kset *btrfs_kset;
796 
797 /* /sys/kernel/debug/btrfs */
798 static struct dentry *btrfs_debugfs_root_dentry;
799 
800 /* Debugging tunables and exported data */
801 u64 btrfs_debugfs_test;
802 
803 /*
804  * Can be called by the device discovery thread.
805  * And parent can be specified for seed device
806  */
807 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
808                                 struct kobject *parent)
809 {
810         int error;
811 
812         init_completion(&fs_devs->kobj_unregister);
813         fs_devs->fsid_kobj.kset = btrfs_kset;
814         error = kobject_init_and_add(&fs_devs->fsid_kobj,
815                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
816         return error;
817 }
818 
819 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
820 {
821         int error;
822         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
823         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
824 
825         btrfs_set_fs_info_ptr(fs_info);
826 
827         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
828         if (error)
829                 return error;
830 
831         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
832         if (error) {
833                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
834                 return error;
835         }
836 
837         error = sysfs_create_group(fsid_kobj,
838                                    &btrfs_feature_attr_group);
839         if (error)
840                 goto failure;
841 
842         error = addrm_unknown_feature_attrs(fs_info, true);
843         if (error)
844                 goto failure;
845 
846         fs_info->space_info_kobj = kobject_create_and_add("allocation",
847                                                   fsid_kobj);
848         if (!fs_info->space_info_kobj) {
849                 error = -ENOMEM;
850                 goto failure;
851         }
852 
853         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
854         if (error)
855                 goto failure;
856 
857         return 0;
858 failure:
859         btrfs_sysfs_remove_mounted(fs_info);
860         return error;
861 }
862 
863 
864 /*
865  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
866  * values in superblock. Call after any changes to incompat/compat_ro flags
867  */
868 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
869                 u64 bit, enum btrfs_feature_set set)
870 {
871         struct btrfs_fs_devices *fs_devs;
872         struct kobject *fsid_kobj;
873         u64 features;
874         int ret;
875 
876         if (!fs_info)
877                 return;
878 
879         features = get_features(fs_info, set);
880         ASSERT(bit & supported_feature_masks[set]);
881 
882         fs_devs = fs_info->fs_devices;
883         fsid_kobj = &fs_devs->fsid_kobj;
884 
885         if (!fsid_kobj->state_initialized)
886                 return;
887 
888         /*
889          * FIXME: this is too heavy to update just one value, ideally we'd like
890          * to use sysfs_update_group but some refactoring is needed first.
891          */
892         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
893         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
894 }
895 
896 static int btrfs_init_debugfs(void)
897 {
898 #ifdef CONFIG_DEBUG_FS
899         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
900         if (!btrfs_debugfs_root_dentry)
901                 return -ENOMEM;
902 
903         /*
904          * Example code, how to export data through debugfs.
905          *
906          * file:        /sys/kernel/debug/btrfs/test
907          * contents of: btrfs_debugfs_test
908          */
909 #ifdef CONFIG_BTRFS_DEBUG
910         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
911                         &btrfs_debugfs_test);
912 #endif
913 
914 #endif
915         return 0;
916 }
917 
918 int __init btrfs_init_sysfs(void)
919 {
920         int ret;
921 
922         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
923         if (!btrfs_kset)
924                 return -ENOMEM;
925 
926         ret = btrfs_init_debugfs();
927         if (ret)
928                 goto out1;
929 
930         init_feature_attrs();
931         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
932         if (ret)
933                 goto out2;
934         ret = sysfs_merge_group(&btrfs_kset->kobj,
935                                 &btrfs_static_feature_attr_group);
936         if (ret)
937                 goto out_remove_group;
938 
939         return 0;
940 
941 out_remove_group:
942         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
943 out2:
944         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
945 out1:
946         kset_unregister(btrfs_kset);
947 
948         return ret;
949 }
950 
951 void __cold btrfs_exit_sysfs(void)
952 {
953         sysfs_unmerge_group(&btrfs_kset->kobj,
954                             &btrfs_static_feature_attr_group);
955         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
956         kset_unregister(btrfs_kset);
957         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
958 }
959 
960 

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