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

Version: ~ [ linux-5.3-rc5 ] ~ [ linux-5.2.9 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.67 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.139 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.189 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.189 ] ~ [ 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-3.16.72 ] ~ [ 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 /*
  2  * Copyright (C) 2007 Oracle.  All rights reserved.
  3  *
  4  * This program is free software; you can redistribute it and/or
  5  * modify it under the terms of the GNU General Public
  6  * License v2 as published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 11  * General Public License for more details.
 12  *
 13  * You should have received a copy of the GNU General Public
 14  * License along with this program; if not, write to the
 15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 16  * Boston, MA 021110-1307, USA.
 17  */
 18 
 19 #include <linux/sched.h>
 20 #include <linux/slab.h>
 21 #include <linux/spinlock.h>
 22 #include <linux/completion.h>
 23 #include <linux/buffer_head.h>
 24 #include <linux/kobject.h>
 25 #include <linux/bug.h>
 26 #include <linux/genhd.h>
 27 #include <linux/debugfs.h>
 28 
 29 #include "ctree.h"
 30 #include "disk-io.h"
 31 #include "transaction.h"
 32 #include "sysfs.h"
 33 #include "volumes.h"
 34 
 35 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
 36 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
 37 
 38 static u64 get_features(struct btrfs_fs_info *fs_info,
 39                         enum btrfs_feature_set set)
 40 {
 41         struct btrfs_super_block *disk_super = fs_info->super_copy;
 42         if (set == FEAT_COMPAT)
 43                 return btrfs_super_compat_flags(disk_super);
 44         else if (set == FEAT_COMPAT_RO)
 45                 return btrfs_super_compat_ro_flags(disk_super);
 46         else
 47                 return btrfs_super_incompat_flags(disk_super);
 48 }
 49 
 50 static void set_features(struct btrfs_fs_info *fs_info,
 51                          enum btrfs_feature_set set, u64 features)
 52 {
 53         struct btrfs_super_block *disk_super = fs_info->super_copy;
 54         if (set == FEAT_COMPAT)
 55                 btrfs_set_super_compat_flags(disk_super, features);
 56         else if (set == FEAT_COMPAT_RO)
 57                 btrfs_set_super_compat_ro_flags(disk_super, features);
 58         else
 59                 btrfs_set_super_incompat_flags(disk_super, features);
 60 }
 61 
 62 static int can_modify_feature(struct btrfs_feature_attr *fa)
 63 {
 64         int val = 0;
 65         u64 set, clear;
 66         switch (fa->feature_set) {
 67         case FEAT_COMPAT:
 68                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 69                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 70                 break;
 71         case FEAT_COMPAT_RO:
 72                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 73                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 74                 break;
 75         case FEAT_INCOMPAT:
 76                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 77                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 78                 break;
 79         default:
 80                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
 81                                 fa->feature_set);
 82                 return 0;
 83         }
 84 
 85         if (set & fa->feature_bit)
 86                 val |= 1;
 87         if (clear & fa->feature_bit)
 88                 val |= 2;
 89 
 90         return val;
 91 }
 92 
 93 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
 94                                        struct kobj_attribute *a, char *buf)
 95 {
 96         int val = 0;
 97         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 98         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 99         if (fs_info) {
100                 u64 features = get_features(fs_info, fa->feature_set);
101                 if (features & fa->feature_bit)
102                         val = 1;
103         } else
104                 val = can_modify_feature(fa);
105 
106         return snprintf(buf, PAGE_SIZE, "%d\n", val);
107 }
108 
109 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
110                                         struct kobj_attribute *a,
111                                         const char *buf, size_t count)
112 {
113         struct btrfs_fs_info *fs_info;
114         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
115         u64 features, set, clear;
116         unsigned long val;
117         int ret;
118 
119         fs_info = to_fs_info(kobj);
120         if (!fs_info)
121                 return -EPERM;
122 
123         if (fs_info->sb->s_flags & MS_RDONLY)
124                 return -EROFS;
125 
126         ret = kstrtoul(skip_spaces(buf), 0, &val);
127         if (ret)
128                 return ret;
129 
130         if (fa->feature_set == FEAT_COMPAT) {
131                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
132                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
133         } else if (fa->feature_set == FEAT_COMPAT_RO) {
134                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
135                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
136         } else {
137                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
138                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
139         }
140 
141         features = get_features(fs_info, fa->feature_set);
142 
143         /* Nothing to do */
144         if ((val && (features & fa->feature_bit)) ||
145             (!val && !(features & fa->feature_bit)))
146                 return count;
147 
148         if ((val && !(set & fa->feature_bit)) ||
149             (!val && !(clear & fa->feature_bit))) {
150                 btrfs_info(fs_info,
151                         "%sabling feature %s on mounted fs is not supported.",
152                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
153                 return -EPERM;
154         }
155 
156         btrfs_info(fs_info, "%s %s feature flag",
157                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
158 
159         spin_lock(&fs_info->super_lock);
160         features = get_features(fs_info, fa->feature_set);
161         if (val)
162                 features |= fa->feature_bit;
163         else
164                 features &= ~fa->feature_bit;
165         set_features(fs_info, fa->feature_set, features);
166         spin_unlock(&fs_info->super_lock);
167 
168         /*
169          * We don't want to do full transaction commit from inside sysfs
170          */
171         btrfs_set_pending(fs_info, COMMIT);
172         wake_up_process(fs_info->transaction_kthread);
173 
174         return count;
175 }
176 
177 static umode_t btrfs_feature_visible(struct kobject *kobj,
178                                      struct attribute *attr, int unused)
179 {
180         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
181         umode_t mode = attr->mode;
182 
183         if (fs_info) {
184                 struct btrfs_feature_attr *fa;
185                 u64 features;
186 
187                 fa = attr_to_btrfs_feature_attr(attr);
188                 features = get_features(fs_info, fa->feature_set);
189 
190                 if (can_modify_feature(fa))
191                         mode |= S_IWUSR;
192                 else if (!(features & fa->feature_bit))
193                         mode = 0;
194         }
195 
196         return mode;
197 }
198 
199 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
200 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
201 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
202 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
203 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
204 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
205 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
206 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
207 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
208 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
209 
210 static struct attribute *btrfs_supported_feature_attrs[] = {
211         BTRFS_FEAT_ATTR_PTR(mixed_backref),
212         BTRFS_FEAT_ATTR_PTR(default_subvol),
213         BTRFS_FEAT_ATTR_PTR(mixed_groups),
214         BTRFS_FEAT_ATTR_PTR(compress_lzo),
215         BTRFS_FEAT_ATTR_PTR(big_metadata),
216         BTRFS_FEAT_ATTR_PTR(extended_iref),
217         BTRFS_FEAT_ATTR_PTR(raid56),
218         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
219         BTRFS_FEAT_ATTR_PTR(no_holes),
220         BTRFS_FEAT_ATTR_PTR(free_space_tree),
221         NULL
222 };
223 
224 static const struct attribute_group btrfs_feature_attr_group = {
225         .name = "features",
226         .is_visible = btrfs_feature_visible,
227         .attrs = btrfs_supported_feature_attrs,
228 };
229 
230 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
231 {
232         u64 val;
233         if (lock)
234                 spin_lock(lock);
235         val = *value_ptr;
236         if (lock)
237                 spin_unlock(lock);
238         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
239 }
240 
241 static ssize_t global_rsv_size_show(struct kobject *kobj,
242                                     struct kobj_attribute *ka, char *buf)
243 {
244         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
245         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
246         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
247 }
248 BTRFS_ATTR(global_rsv_size, global_rsv_size_show);
249 
250 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
251                                         struct kobj_attribute *a, char *buf)
252 {
253         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
254         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
255         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
256 }
257 BTRFS_ATTR(global_rsv_reserved, global_rsv_reserved_show);
258 
259 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
260 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
261 
262 static ssize_t raid_bytes_show(struct kobject *kobj,
263                                struct kobj_attribute *attr, char *buf);
264 BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
265 BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
266 
267 static ssize_t raid_bytes_show(struct kobject *kobj,
268                                struct kobj_attribute *attr, char *buf)
269 
270 {
271         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
272         struct btrfs_block_group_cache *block_group;
273         int index = to_raid_kobj(kobj)->raid_type;
274         u64 val = 0;
275 
276         down_read(&sinfo->groups_sem);
277         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
278                 if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
279                         val += block_group->key.offset;
280                 else
281                         val += btrfs_block_group_used(&block_group->item);
282         }
283         up_read(&sinfo->groups_sem);
284         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
285 }
286 
287 static struct attribute *raid_attributes[] = {
288         BTRFS_RAID_ATTR_PTR(total_bytes),
289         BTRFS_RAID_ATTR_PTR(used_bytes),
290         NULL
291 };
292 
293 static void release_raid_kobj(struct kobject *kobj)
294 {
295         kfree(to_raid_kobj(kobj));
296 }
297 
298 struct kobj_type btrfs_raid_ktype = {
299         .sysfs_ops = &kobj_sysfs_ops,
300         .release = release_raid_kobj,
301         .default_attrs = raid_attributes,
302 };
303 
304 #define SPACE_INFO_ATTR(field)                                          \
305 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
306                                              struct kobj_attribute *a,  \
307                                              char *buf)                 \
308 {                                                                       \
309         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
310         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
311 }                                                                       \
312 BTRFS_ATTR(field, btrfs_space_info_show_##field)
313 
314 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
315                                                        struct kobj_attribute *a,
316                                                        char *buf)
317 {
318         struct btrfs_space_info *sinfo = to_space_info(kobj);
319         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
320         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
321 }
322 
323 SPACE_INFO_ATTR(flags);
324 SPACE_INFO_ATTR(total_bytes);
325 SPACE_INFO_ATTR(bytes_used);
326 SPACE_INFO_ATTR(bytes_pinned);
327 SPACE_INFO_ATTR(bytes_reserved);
328 SPACE_INFO_ATTR(bytes_may_use);
329 SPACE_INFO_ATTR(bytes_readonly);
330 SPACE_INFO_ATTR(disk_used);
331 SPACE_INFO_ATTR(disk_total);
332 BTRFS_ATTR(total_bytes_pinned, btrfs_space_info_show_total_bytes_pinned);
333 
334 static struct attribute *space_info_attrs[] = {
335         BTRFS_ATTR_PTR(flags),
336         BTRFS_ATTR_PTR(total_bytes),
337         BTRFS_ATTR_PTR(bytes_used),
338         BTRFS_ATTR_PTR(bytes_pinned),
339         BTRFS_ATTR_PTR(bytes_reserved),
340         BTRFS_ATTR_PTR(bytes_may_use),
341         BTRFS_ATTR_PTR(bytes_readonly),
342         BTRFS_ATTR_PTR(disk_used),
343         BTRFS_ATTR_PTR(disk_total),
344         BTRFS_ATTR_PTR(total_bytes_pinned),
345         NULL,
346 };
347 
348 static void space_info_release(struct kobject *kobj)
349 {
350         struct btrfs_space_info *sinfo = to_space_info(kobj);
351         percpu_counter_destroy(&sinfo->total_bytes_pinned);
352         kfree(sinfo);
353 }
354 
355 struct kobj_type space_info_ktype = {
356         .sysfs_ops = &kobj_sysfs_ops,
357         .release = space_info_release,
358         .default_attrs = space_info_attrs,
359 };
360 
361 static const struct attribute *allocation_attrs[] = {
362         BTRFS_ATTR_PTR(global_rsv_reserved),
363         BTRFS_ATTR_PTR(global_rsv_size),
364         NULL,
365 };
366 
367 static ssize_t btrfs_label_show(struct kobject *kobj,
368                                 struct kobj_attribute *a, char *buf)
369 {
370         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
371         char *label = fs_info->super_copy->label;
372         ssize_t ret;
373 
374         spin_lock(&fs_info->super_lock);
375         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
376         spin_unlock(&fs_info->super_lock);
377 
378         return ret;
379 }
380 
381 static ssize_t btrfs_label_store(struct kobject *kobj,
382                                  struct kobj_attribute *a,
383                                  const char *buf, size_t len)
384 {
385         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
386         size_t p_len;
387 
388         if (!fs_info)
389                 return -EPERM;
390 
391         if (fs_info->sb->s_flags & MS_RDONLY)
392                 return -EROFS;
393 
394         /*
395          * p_len is the len until the first occurrence of either
396          * '\n' or '\0'
397          */
398         p_len = strcspn(buf, "\n");
399 
400         if (p_len >= BTRFS_LABEL_SIZE)
401                 return -EINVAL;
402 
403         spin_lock(&fs_info->super_lock);
404         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
405         memcpy(fs_info->super_copy->label, buf, p_len);
406         spin_unlock(&fs_info->super_lock);
407 
408         /*
409          * We don't want to do full transaction commit from inside sysfs
410          */
411         btrfs_set_pending(fs_info, COMMIT);
412         wake_up_process(fs_info->transaction_kthread);
413 
414         return len;
415 }
416 BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);
417 
418 static ssize_t btrfs_nodesize_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", fs_info->super_copy->nodesize);
424 }
425 
426 BTRFS_ATTR(nodesize, btrfs_nodesize_show);
427 
428 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
429                                 struct kobj_attribute *a, char *buf)
430 {
431         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
432 
433         return snprintf(buf, PAGE_SIZE, "%u\n",
434                         fs_info->super_copy->sectorsize);
435 }
436 
437 BTRFS_ATTR(sectorsize, btrfs_sectorsize_show);
438 
439 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
440                                 struct kobj_attribute *a, char *buf)
441 {
442         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
443 
444         return snprintf(buf, PAGE_SIZE, "%u\n",
445                         fs_info->super_copy->sectorsize);
446 }
447 
448 BTRFS_ATTR(clone_alignment, btrfs_clone_alignment_show);
449 
450 static const struct attribute *btrfs_attrs[] = {
451         BTRFS_ATTR_PTR(label),
452         BTRFS_ATTR_PTR(nodesize),
453         BTRFS_ATTR_PTR(sectorsize),
454         BTRFS_ATTR_PTR(clone_alignment),
455         NULL,
456 };
457 
458 static void btrfs_release_fsid_kobj(struct kobject *kobj)
459 {
460         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
461 
462         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
463         complete(&fs_devs->kobj_unregister);
464 }
465 
466 static struct kobj_type btrfs_ktype = {
467         .sysfs_ops      = &kobj_sysfs_ops,
468         .release        = btrfs_release_fsid_kobj,
469 };
470 
471 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
472 {
473         if (kobj->ktype != &btrfs_ktype)
474                 return NULL;
475         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
476 }
477 
478 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
479 {
480         if (kobj->ktype != &btrfs_ktype)
481                 return NULL;
482         return to_fs_devs(kobj)->fs_info;
483 }
484 
485 #define NUM_FEATURE_BITS 64
486 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
487 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
488 
489 static const u64 supported_feature_masks[3] = {
490         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
491         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
492         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
493 };
494 
495 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
496 {
497         int set;
498 
499         for (set = 0; set < FEAT_MAX; set++) {
500                 int i;
501                 struct attribute *attrs[2];
502                 struct attribute_group agroup = {
503                         .name = "features",
504                         .attrs = attrs,
505                 };
506                 u64 features = get_features(fs_info, set);
507                 features &= ~supported_feature_masks[set];
508 
509                 if (!features)
510                         continue;
511 
512                 attrs[1] = NULL;
513                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
514                         struct btrfs_feature_attr *fa;
515 
516                         if (!(features & (1ULL << i)))
517                                 continue;
518 
519                         fa = &btrfs_feature_attrs[set][i];
520                         attrs[0] = &fa->kobj_attr.attr;
521                         if (add) {
522                                 int ret;
523                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
524                                                         &agroup);
525                                 if (ret)
526                                         return ret;
527                         } else
528                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
529                                                     &agroup);
530                 }
531 
532         }
533         return 0;
534 }
535 
536 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
537 {
538         if (fs_devs->device_dir_kobj) {
539                 kobject_del(fs_devs->device_dir_kobj);
540                 kobject_put(fs_devs->device_dir_kobj);
541                 fs_devs->device_dir_kobj = NULL;
542         }
543 
544         if (fs_devs->fsid_kobj.state_initialized) {
545                 kobject_del(&fs_devs->fsid_kobj);
546                 kobject_put(&fs_devs->fsid_kobj);
547                 wait_for_completion(&fs_devs->kobj_unregister);
548         }
549 }
550 
551 /* when fs_devs is NULL it will remove all fsid kobject */
552 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
553 {
554         struct list_head *fs_uuids = btrfs_get_fs_uuids();
555 
556         if (fs_devs) {
557                 __btrfs_sysfs_remove_fsid(fs_devs);
558                 return;
559         }
560 
561         list_for_each_entry(fs_devs, fs_uuids, list) {
562                 __btrfs_sysfs_remove_fsid(fs_devs);
563         }
564 }
565 
566 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
567 {
568         btrfs_reset_fs_info_ptr(fs_info);
569 
570         if (fs_info->space_info_kobj) {
571                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
572                 kobject_del(fs_info->space_info_kobj);
573                 kobject_put(fs_info->space_info_kobj);
574         }
575         addrm_unknown_feature_attrs(fs_info, false);
576         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
577         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
578         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
579 }
580 
581 const char * const btrfs_feature_set_names[3] = {
582         [FEAT_COMPAT]    = "compat",
583         [FEAT_COMPAT_RO] = "compat_ro",
584         [FEAT_INCOMPAT]  = "incompat",
585 };
586 
587 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
588 {
589         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
590         int len = 0;
591         int i;
592         char *str;
593 
594         str = kmalloc(bufsize, GFP_KERNEL);
595         if (!str)
596                 return str;
597 
598         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
599                 const char *name;
600 
601                 if (!(flags & (1ULL << i)))
602                         continue;
603 
604                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
605                 len += snprintf(str + len, bufsize - len, "%s%s",
606                                 len ? "," : "", name);
607         }
608 
609         return str;
610 }
611 
612 static void init_feature_attrs(void)
613 {
614         struct btrfs_feature_attr *fa;
615         int set, i;
616 
617         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
618                      ARRAY_SIZE(btrfs_feature_attrs));
619         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
620                      ARRAY_SIZE(btrfs_feature_attrs[0]));
621 
622         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
623         memset(btrfs_unknown_feature_names, 0,
624                sizeof(btrfs_unknown_feature_names));
625 
626         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
627                 struct btrfs_feature_attr *sfa;
628                 struct attribute *a = btrfs_supported_feature_attrs[i];
629                 int bit;
630                 sfa = attr_to_btrfs_feature_attr(a);
631                 bit = ilog2(sfa->feature_bit);
632                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
633 
634                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
635         }
636 
637         for (set = 0; set < FEAT_MAX; set++) {
638                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
639                         char *name = btrfs_unknown_feature_names[set][i];
640                         fa = &btrfs_feature_attrs[set][i];
641 
642                         if (fa->kobj_attr.attr.name)
643                                 continue;
644 
645                         snprintf(name, 13, "%s:%u",
646                                  btrfs_feature_set_names[set], i);
647 
648                         fa->kobj_attr.attr.name = name;
649                         fa->kobj_attr.attr.mode = S_IRUGO;
650                         fa->feature_set = set;
651                         fa->feature_bit = 1ULL << i;
652                 }
653         }
654 }
655 
656 /* when one_device is NULL, it removes all device links */
657 
658 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
659                 struct btrfs_device *one_device)
660 {
661         struct hd_struct *disk;
662         struct kobject *disk_kobj;
663 
664         if (!fs_devices->device_dir_kobj)
665                 return -EINVAL;
666 
667         if (one_device && one_device->bdev) {
668                 disk = one_device->bdev->bd_part;
669                 disk_kobj = &part_to_dev(disk)->kobj;
670 
671                 sysfs_remove_link(fs_devices->device_dir_kobj,
672                                                 disk_kobj->name);
673         }
674 
675         if (one_device)
676                 return 0;
677 
678         list_for_each_entry(one_device,
679                         &fs_devices->devices, dev_list) {
680                 if (!one_device->bdev)
681                         continue;
682                 disk = one_device->bdev->bd_part;
683                 disk_kobj = &part_to_dev(disk)->kobj;
684 
685                 sysfs_remove_link(fs_devices->device_dir_kobj,
686                                                 disk_kobj->name);
687         }
688 
689         return 0;
690 }
691 
692 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
693 {
694         if (!fs_devs->device_dir_kobj)
695                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
696                                                 &fs_devs->fsid_kobj);
697 
698         if (!fs_devs->device_dir_kobj)
699                 return -ENOMEM;
700 
701         return 0;
702 }
703 
704 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
705                                 struct btrfs_device *one_device)
706 {
707         int error = 0;
708         struct btrfs_device *dev;
709 
710         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
711                 struct hd_struct *disk;
712                 struct kobject *disk_kobj;
713 
714                 if (!dev->bdev)
715                         continue;
716 
717                 if (one_device && one_device != dev)
718                         continue;
719 
720                 disk = dev->bdev->bd_part;
721                 disk_kobj = &part_to_dev(disk)->kobj;
722 
723                 error = sysfs_create_link(fs_devices->device_dir_kobj,
724                                           disk_kobj, disk_kobj->name);
725                 if (error)
726                         break;
727         }
728 
729         return error;
730 }
731 
732 /* /sys/fs/btrfs/ entry */
733 static struct kset *btrfs_kset;
734 
735 /* /sys/kernel/debug/btrfs */
736 static struct dentry *btrfs_debugfs_root_dentry;
737 
738 /* Debugging tunables and exported data */
739 u64 btrfs_debugfs_test;
740 
741 /*
742  * Can be called by the device discovery thread.
743  * And parent can be specified for seed device
744  */
745 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
746                                 struct kobject *parent)
747 {
748         int error;
749 
750         init_completion(&fs_devs->kobj_unregister);
751         fs_devs->fsid_kobj.kset = btrfs_kset;
752         error = kobject_init_and_add(&fs_devs->fsid_kobj,
753                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
754         return error;
755 }
756 
757 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
758 {
759         int error;
760         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
761         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
762 
763         btrfs_set_fs_info_ptr(fs_info);
764 
765         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
766         if (error)
767                 return error;
768 
769         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
770         if (error) {
771                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
772                 return error;
773         }
774 
775         error = sysfs_create_group(fsid_kobj,
776                                    &btrfs_feature_attr_group);
777         if (error)
778                 goto failure;
779 
780         error = addrm_unknown_feature_attrs(fs_info, true);
781         if (error)
782                 goto failure;
783 
784         fs_info->space_info_kobj = kobject_create_and_add("allocation",
785                                                   fsid_kobj);
786         if (!fs_info->space_info_kobj) {
787                 error = -ENOMEM;
788                 goto failure;
789         }
790 
791         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
792         if (error)
793                 goto failure;
794 
795         return 0;
796 failure:
797         btrfs_sysfs_remove_mounted(fs_info);
798         return error;
799 }
800 
801 
802 /*
803  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
804  * values in superblock. Call after any changes to incompat/compat_ro flags
805  */
806 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
807                 u64 bit, enum btrfs_feature_set set)
808 {
809         struct btrfs_fs_devices *fs_devs;
810         struct kobject *fsid_kobj;
811         u64 features;
812         int ret;
813 
814         if (!fs_info)
815                 return;
816 
817         features = get_features(fs_info, set);
818         ASSERT(bit & supported_feature_masks[set]);
819 
820         fs_devs = fs_info->fs_devices;
821         fsid_kobj = &fs_devs->fsid_kobj;
822 
823         if (!fsid_kobj->state_initialized)
824                 return;
825 
826         /*
827          * FIXME: this is too heavy to update just one value, ideally we'd like
828          * to use sysfs_update_group but some refactoring is needed first.
829          */
830         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
831         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
832 }
833 
834 static int btrfs_init_debugfs(void)
835 {
836 #ifdef CONFIG_DEBUG_FS
837         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
838         if (!btrfs_debugfs_root_dentry)
839                 return -ENOMEM;
840 
841         /*
842          * Example code, how to export data through debugfs.
843          *
844          * file:        /sys/kernel/debug/btrfs/test
845          * contents of: btrfs_debugfs_test
846          */
847 #ifdef CONFIG_BTRFS_DEBUG
848         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
849                         &btrfs_debugfs_test);
850 #endif
851 
852 #endif
853         return 0;
854 }
855 
856 int btrfs_init_sysfs(void)
857 {
858         int ret;
859 
860         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
861         if (!btrfs_kset)
862                 return -ENOMEM;
863 
864         ret = btrfs_init_debugfs();
865         if (ret)
866                 goto out1;
867 
868         init_feature_attrs();
869         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
870         if (ret)
871                 goto out2;
872 
873         return 0;
874 out2:
875         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
876 out1:
877         kset_unregister(btrfs_kset);
878 
879         return ret;
880 }
881 
882 void btrfs_exit_sysfs(void)
883 {
884         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
885         kset_unregister(btrfs_kset);
886         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
887 }
888 
889 

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