GNU Linux-libre 4.9.308-gnu1
[releases.git] / fs / btrfs / sysfs.c
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         if (error) {
755                 kobject_put(&fs_devs->fsid_kobj);
756                 return error;
757         }
758
759         return 0;
760 }
761
762 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
763 {
764         int error;
765         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
766         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
767
768         btrfs_set_fs_info_ptr(fs_info);
769
770         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
771         if (error)
772                 return error;
773
774         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
775         if (error) {
776                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
777                 return error;
778         }
779
780         error = sysfs_create_group(fsid_kobj,
781                                    &btrfs_feature_attr_group);
782         if (error)
783                 goto failure;
784
785         error = addrm_unknown_feature_attrs(fs_info, true);
786         if (error)
787                 goto failure;
788
789         fs_info->space_info_kobj = kobject_create_and_add("allocation",
790                                                   fsid_kobj);
791         if (!fs_info->space_info_kobj) {
792                 error = -ENOMEM;
793                 goto failure;
794         }
795
796         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
797         if (error)
798                 goto failure;
799
800         return 0;
801 failure:
802         btrfs_sysfs_remove_mounted(fs_info);
803         return error;
804 }
805
806
807 /*
808  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
809  * values in superblock. Call after any changes to incompat/compat_ro flags
810  */
811 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
812                 u64 bit, enum btrfs_feature_set set)
813 {
814         struct btrfs_fs_devices *fs_devs;
815         struct kobject *fsid_kobj;
816         u64 features;
817         int ret;
818
819         if (!fs_info)
820                 return;
821
822         features = get_features(fs_info, set);
823         ASSERT(bit & supported_feature_masks[set]);
824
825         fs_devs = fs_info->fs_devices;
826         fsid_kobj = &fs_devs->fsid_kobj;
827
828         if (!fsid_kobj->state_initialized)
829                 return;
830
831         /*
832          * FIXME: this is too heavy to update just one value, ideally we'd like
833          * to use sysfs_update_group but some refactoring is needed first.
834          */
835         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
836         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
837 }
838
839 static int btrfs_init_debugfs(void)
840 {
841 #ifdef CONFIG_DEBUG_FS
842         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
843         if (!btrfs_debugfs_root_dentry)
844                 return -ENOMEM;
845
846         /*
847          * Example code, how to export data through debugfs.
848          *
849          * file:        /sys/kernel/debug/btrfs/test
850          * contents of: btrfs_debugfs_test
851          */
852 #ifdef CONFIG_BTRFS_DEBUG
853         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
854                         &btrfs_debugfs_test);
855 #endif
856
857 #endif
858         return 0;
859 }
860
861 int btrfs_init_sysfs(void)
862 {
863         int ret;
864
865         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
866         if (!btrfs_kset)
867                 return -ENOMEM;
868
869         ret = btrfs_init_debugfs();
870         if (ret)
871                 goto out1;
872
873         init_feature_attrs();
874         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
875         if (ret)
876                 goto out2;
877
878         return 0;
879 out2:
880         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
881 out1:
882         kset_unregister(btrfs_kset);
883
884         return ret;
885 }
886
887 void btrfs_exit_sysfs(void)
888 {
889         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
890         kset_unregister(btrfs_kset);
891         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
892 }
893