fs/btrfs/sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/mm.h>
   8 #include <linux/slab.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/completion.h>
  11 #include <linux/bug.h>
  12 #include <crypto/hash.h>
  13
  14 #include "ctree.h"
  15 #include "disk-io.h"
  16 #include "transaction.h"
  17 #include "sysfs.h"
  18 #include "volumes.h"
  19 #include "space-info.h"
  20 #include "block-group.h"
  21
  22 struct btrfs_feature_attr {
  23         struct kobj_attribute kobj_attr;
  24         enum btrfs_feature_set feature_set;
  25         u64 feature_bit;
  26 };
  27
  28 /* For raid type sysfs entries */
  29 struct raid_kobject {
  30         u64 flags;
  31         struct kobject kobj;
  32 };
  33
  34 #define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)                   \
  35 {                                                                       \
  36         .attr   = { .name = __stringify(_name), .mode = _mode },        \
  37         .show   = _show,                                                \
  38         .store  = _store,                                               \
  39 }
  40
  41 #define BTRFS_ATTR_RW(_prefix, _name, _show, _store)                    \
  42         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  43                         __INIT_KOBJ_ATTR(_name, 0644, _show, _store)
  44
  45 #define BTRFS_ATTR(_prefix, _name, _show)                               \
  46         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  47                         __INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
  48
  49 #define BTRFS_ATTR_PTR(_prefix, _name)                                  \
  50         (&btrfs_attr_##_prefix##_##_name.attr)
  51
  52 #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
  53 static struct btrfs_feature_attr btrfs_attr_features_##_name = {             \
  54         .kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,                        \
  55                                       btrfs_feature_attr_show,               \
  56                                       btrfs_feature_attr_store),             \
  57         .feature_set    = _feature_set,                                      \
  58         .feature_bit    = _feature_prefix ##_## _feature_bit,                \
  59 }
  60 #define BTRFS_FEAT_ATTR_PTR(_name)                                           \
  61         (&btrfs_attr_features_##_name.kobj_attr.attr)
  62
  63 #define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
  64         BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
  65 #define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
  66         BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
  67 #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
  68         BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)
  69
  70 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  71 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
  72
  73 static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
  74 {
  75         return container_of(a, struct btrfs_feature_attr, kobj_attr);
  76 }
  77
  78 static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
  79 {
  80         return container_of(attr, struct kobj_attribute, attr);
  81 }
  82
  83 static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
  84                 struct attribute *attr)
  85 {
  86         return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
  87 }
  88
  89 static u64 get_features(struct btrfs_fs_info *fs_info,
  90                         enum btrfs_feature_set set)
  91 {
  92         struct btrfs_super_block *disk_super = fs_info->super_copy;
  93         if (set == FEAT_COMPAT)
  94                 return btrfs_super_compat_flags(disk_super);
  95         else if (set == FEAT_COMPAT_RO)
  96                 return btrfs_super_compat_ro_flags(disk_super);
  97         else
  98                 return btrfs_super_incompat_flags(disk_super);
  99 }
 100
 101 static void set_features(struct btrfs_fs_info *fs_info,
 102                          enum btrfs_feature_set set, u64 features)
 103 {
 104         struct btrfs_super_block *disk_super = fs_info->super_copy;
 105         if (set == FEAT_COMPAT)
 106                 btrfs_set_super_compat_flags(disk_super, features);
 107         else if (set == FEAT_COMPAT_RO)
 108                 btrfs_set_super_compat_ro_flags(disk_super, features);
 109         else
 110                 btrfs_set_super_incompat_flags(disk_super, features);
 111 }
 112
 113 static int can_modify_feature(struct btrfs_feature_attr *fa)
 114 {
 115         int val = 0;
 116         u64 set, clear;
 117         switch (fa->feature_set) {
 118         case FEAT_COMPAT:
 119                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 120                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 121                 break;
 122         case FEAT_COMPAT_RO:
 123                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 124                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 125                 break;
 126         case FEAT_INCOMPAT:
 127                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 128                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 129                 break;
 130         default:
 131                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
 132                                 fa->feature_set);
 133                 return 0;
 134         }
 135
 136         if (set & fa->feature_bit)
 137                 val |= 1;
 138         if (clear & fa->feature_bit)
 139                 val |= 2;
 140
 141         return val;
 142 }
 143
 144 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
 145                                        struct kobj_attribute *a, char *buf)
 146 {
 147         int val = 0;
 148         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 149         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 150         if (fs_info) {
 151                 u64 features = get_features(fs_info, fa->feature_set);
 152                 if (features & fa->feature_bit)
 153                         val = 1;
 154         } else
 155                 val = can_modify_feature(fa);
 156
 157         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 158 }
 159
 160 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 161                                         struct kobj_attribute *a,
 162                                         const char *buf, size_t count)
 163 {
 164         struct btrfs_fs_info *fs_info;
 165         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 166         u64 features, set, clear;
 167         unsigned long val;
 168         int ret;
 169
 170         fs_info = to_fs_info(kobj);
 171         if (!fs_info)
 172                 return -EPERM;
 173
 174         if (sb_rdonly(fs_info->sb))
 175                 return -EROFS;
 176
 177         ret = kstrtoul(skip_spaces(buf), 0, &val);
 178         if (ret)
 179                 return ret;
 180
 181         if (fa->feature_set == FEAT_COMPAT) {
 182                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 183                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 184         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 185                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 186                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 187         } else {
 188                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 189                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 190         }
 191
 192         features = get_features(fs_info, fa->feature_set);
 193
 194         /* Nothing to do */
 195         if ((val && (features & fa->feature_bit)) ||
 196             (!val && !(features & fa->feature_bit)))
 197                 return count;
 198
 199         if ((val && !(set & fa->feature_bit)) ||
 200             (!val && !(clear & fa->feature_bit))) {
 201                 btrfs_info(fs_info,
 202                         "%sabling feature %s on mounted fs is not supported.",
 203                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 204                 return -EPERM;
 205         }
 206
 207         btrfs_info(fs_info, "%s %s feature flag",
 208                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 209
 210         spin_lock(&fs_info->super_lock);
 211         features = get_features(fs_info, fa->feature_set);
 212         if (val)
 213                 features |= fa->feature_bit;
 214         else
 215                 features &= ~fa->feature_bit;
 216         set_features(fs_info, fa->feature_set, features);
 217         spin_unlock(&fs_info->super_lock);
 218
 219         /*
 220          * We don't want to do full transaction commit from inside sysfs
 221          */
 222         btrfs_set_pending(fs_info, COMMIT);
 223         wake_up_process(fs_info->transaction_kthread);
 224
 225         return count;
 226 }
 227
 228 static umode_t btrfs_feature_visible(struct kobject *kobj,
 229                                      struct attribute *attr, int unused)
 230 {
 231         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 232         umode_t mode = attr->mode;
 233
 234         if (fs_info) {
 235                 struct btrfs_feature_attr *fa;
 236                 u64 features;
 237
 238                 fa = attr_to_btrfs_feature_attr(attr);
 239                 features = get_features(fs_info, fa->feature_set);
 240
 241                 if (can_modify_feature(fa))
 242                         mode |= S_IWUSR;
 243                 else if (!(features & fa->feature_bit))
 244                         mode = 0;
 245         }
 246
 247         return mode;
 248 }
 249
 250 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 251 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 252 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 253 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 254 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
 255 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 256 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 257 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 258 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 259 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 260 BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
 261 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 262 BTRFS_FEAT_ATTR_INCOMPAT(raid1c34, RAID1C34);
 263
 264 static struct attribute *btrfs_supported_feature_attrs[] = {
 265         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 266         BTRFS_FEAT_ATTR_PTR(default_subvol),
 267         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 268         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 269         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 270         BTRFS_FEAT_ATTR_PTR(big_metadata),
 271         BTRFS_FEAT_ATTR_PTR(extended_iref),
 272         BTRFS_FEAT_ATTR_PTR(raid56),
 273         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 274         BTRFS_FEAT_ATTR_PTR(no_holes),
 275         BTRFS_FEAT_ATTR_PTR(metadata_uuid),
 276         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 277         BTRFS_FEAT_ATTR_PTR(raid1c34),
 278         NULL
 279 };
 280
 281 /*
 282  * Features which depend on feature bits and may differ between each fs.
 283  *
 284  * /sys/fs/btrfs/features lists all available features of this kernel while
 285  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 286  * can be changed online.
 287  */
 288 static const struct attribute_group btrfs_feature_attr_group = {
 289         .name = "features",
 290         .is_visible = btrfs_feature_visible,
 291         .attrs = btrfs_supported_feature_attrs,
 292 };
 293
 294 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 295                                  struct kobj_attribute *ka, char *buf)
 296 {
 297         return snprintf(buf, PAGE_SIZE, "0\n");
 298 }
 299 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 300
 301 static ssize_t supported_checksums_show(struct kobject *kobj,
 302                                         struct kobj_attribute *a, char *buf)
 303 {
 304         ssize_t ret = 0;
 305         int i;
 306
 307         for (i = 0; i < btrfs_get_num_csums(); i++) {
 308                 /*
 309                  * This "trick" only works as long as 'enum btrfs_csum_type' has
 310                  * no holes in it
 311                  */
 312                 ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
 313                                 (i == 0 ? "" : " "), btrfs_super_csum_name(i));
 314
 315         }
 316
 317         ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n");
 318         return ret;
 319 }
 320 BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);
 321
 322 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 323         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 324         BTRFS_ATTR_PTR(static_feature, supported_checksums),
 325         NULL
 326 };
 327
 328 /*
 329  * Features which only depend on kernel version.
 330  *
 331  * These are listed in /sys/fs/btrfs/features along with
 332  * btrfs_feature_attr_group
 333  */
 334 static const struct attribute_group btrfs_static_feature_attr_group = {
 335         .name = "features",
 336         .attrs = btrfs_supported_static_feature_attrs,
 337 };
 338
 339 #ifdef CONFIG_BTRFS_DEBUG
 340
 341 /*
 342  * Runtime debugging exported via sysfs
 343  *
 344  * /sys/fs/btrfs/debug - applies to module or all filesystems
 345  * /sys/fs/btrfs/UUID  - applies only to the given filesystem
 346  */
 347 static struct attribute *btrfs_debug_feature_attrs[] = {
 348         NULL
 349 };
 350
 351 static const struct attribute_group btrfs_debug_feature_attr_group = {
 352         .name = "debug",
 353         .attrs = btrfs_debug_feature_attrs,
 354 };
 355
 356 #endif
 357
 358 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 359 {
 360         u64 val;
 361         if (lock)
 362                 spin_lock(lock);
 363         val = *value_ptr;
 364         if (lock)
 365                 spin_unlock(lock);
 366         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 367 }
 368
 369 static ssize_t global_rsv_size_show(struct kobject *kobj,
 370                                     struct kobj_attribute *ka, char *buf)
 371 {
 372         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 373         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 374         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 375 }
 376 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 377
 378 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 379                                         struct kobj_attribute *a, char *buf)
 380 {
 381         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 382         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 383         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 384 }
 385 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 386
 387 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 388 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 389
 390 static ssize_t raid_bytes_show(struct kobject *kobj,
 391                                struct kobj_attribute *attr, char *buf);
 392 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 393 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 394
 395 static ssize_t raid_bytes_show(struct kobject *kobj,
 396                                struct kobj_attribute *attr, char *buf)
 397
 398 {
 399         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 400         struct btrfs_block_group *block_group;
 401         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 402         u64 val = 0;
 403
 404         down_read(&sinfo->groups_sem);
 405         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 406                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 407                         val += block_group->length;
 408                 else
 409                         val += block_group->used;
 410         }
 411         up_read(&sinfo->groups_sem);
 412         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 413 }
 414
 415 static struct attribute *raid_attrs[] = {
 416         BTRFS_ATTR_PTR(raid, total_bytes),
 417         BTRFS_ATTR_PTR(raid, used_bytes),
 418         NULL
 419 };
 420 ATTRIBUTE_GROUPS(raid);
 421
 422 static void release_raid_kobj(struct kobject *kobj)
 423 {
 424         kfree(to_raid_kobj(kobj));
 425 }
 426
 427 static struct kobj_type btrfs_raid_ktype = {
 428         .sysfs_ops = &kobj_sysfs_ops,
 429         .release = release_raid_kobj,
 430         .default_groups = raid_groups,
 431 };
 432
 433 #define SPACE_INFO_ATTR(field)                                          \
 434 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 435                                              struct kobj_attribute *a,  \
 436                                              char *buf)                 \
 437 {                                                                       \
 438         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 439         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 440 }                                                                       \
 441 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 442
 443 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 444                                                        struct kobj_attribute *a,
 445                                                        char *buf)
 446 {
 447         struct btrfs_space_info *sinfo = to_space_info(kobj);
 448         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 449         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 450 }
 451
 452 SPACE_INFO_ATTR(flags);
 453 SPACE_INFO_ATTR(total_bytes);
 454 SPACE_INFO_ATTR(bytes_used);
 455 SPACE_INFO_ATTR(bytes_pinned);
 456 SPACE_INFO_ATTR(bytes_reserved);
 457 SPACE_INFO_ATTR(bytes_may_use);
 458 SPACE_INFO_ATTR(bytes_readonly);
 459 SPACE_INFO_ATTR(disk_used);
 460 SPACE_INFO_ATTR(disk_total);
 461 BTRFS_ATTR(space_info, total_bytes_pinned,
 462            btrfs_space_info_show_total_bytes_pinned);
 463
 464 static struct attribute *space_info_attrs[] = {
 465         BTRFS_ATTR_PTR(space_info, flags),
 466         BTRFS_ATTR_PTR(space_info, total_bytes),
 467         BTRFS_ATTR_PTR(space_info, bytes_used),
 468         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 469         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 470         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 471         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 472         BTRFS_ATTR_PTR(space_info, disk_used),
 473         BTRFS_ATTR_PTR(space_info, disk_total),
 474         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 475         NULL,
 476 };
 477 ATTRIBUTE_GROUPS(space_info);
 478
 479 static void space_info_release(struct kobject *kobj)
 480 {
 481         struct btrfs_space_info *sinfo = to_space_info(kobj);
 482         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 483         kfree(sinfo);
 484 }
 485
 486 static struct kobj_type space_info_ktype = {
 487         .sysfs_ops = &kobj_sysfs_ops,
 488         .release = space_info_release,
 489         .default_groups = space_info_groups,
 490 };
 491
 492 static const struct attribute *allocation_attrs[] = {
 493         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 494         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 495         NULL,
 496 };
 497
 498 static ssize_t btrfs_label_show(struct kobject *kobj,
 499                                 struct kobj_attribute *a, char *buf)
 500 {
 501         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 502         char *label = fs_info->super_copy->label;
 503         ssize_t ret;
 504
 505         spin_lock(&fs_info->super_lock);
 506         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 507         spin_unlock(&fs_info->super_lock);
 508
 509         return ret;
 510 }
 511
 512 static ssize_t btrfs_label_store(struct kobject *kobj,
 513                                  struct kobj_attribute *a,
 514                                  const char *buf, size_t len)
 515 {
 516         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 517         size_t p_len;
 518
 519         if (!fs_info)
 520                 return -EPERM;
 521
 522         if (sb_rdonly(fs_info->sb))
 523                 return -EROFS;
 524
 525         /*
 526          * p_len is the len until the first occurrence of either
 527          * '\n' or '\0'
 528          */
 529         p_len = strcspn(buf, "\n");
 530
 531         if (p_len >= BTRFS_LABEL_SIZE)
 532                 return -EINVAL;
 533
 534         spin_lock(&fs_info->super_lock);
 535         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 536         memcpy(fs_info->super_copy->label, buf, p_len);
 537         spin_unlock(&fs_info->super_lock);
 538
 539         /*
 540          * We don't want to do full transaction commit from inside sysfs
 541          */
 542         btrfs_set_pending(fs_info, COMMIT);
 543         wake_up_process(fs_info->transaction_kthread);
 544
 545         return len;
 546 }
 547 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 548
 549 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 550                                 struct kobj_attribute *a, char *buf)
 551 {
 552         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 553
 554         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 555 }
 556
 557 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 558
 559 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 560                                 struct kobj_attribute *a, char *buf)
 561 {
 562         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 563
 564         return snprintf(buf, PAGE_SIZE, "%u\n",
 565                         fs_info->super_copy->sectorsize);
 566 }
 567
 568 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 569
 570 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 571                                 struct kobj_attribute *a, char *buf)
 572 {
 573         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 574
 575         return snprintf(buf, PAGE_SIZE, "%u\n",
 576                         fs_info->super_copy->sectorsize);
 577 }
 578
 579 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 580
 581 static ssize_t quota_override_show(struct kobject *kobj,
 582                                    struct kobj_attribute *a, char *buf)
 583 {
 584         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 585         int quota_override;
 586
 587         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 588         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 589 }
 590
 591 static ssize_t quota_override_store(struct kobject *kobj,
 592                                     struct kobj_attribute *a,
 593                                     const char *buf, size_t len)
 594 {
 595         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 596         unsigned long knob;
 597         int err;
 598
 599         if (!fs_info)
 600                 return -EPERM;
 601
 602         if (!capable(CAP_SYS_RESOURCE))
 603                 return -EPERM;
 604
 605         err = kstrtoul(buf, 10, &knob);
 606         if (err)
 607                 return err;
 608         if (knob > 1)
 609                 return -EINVAL;
 610
 611         if (knob)
 612                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 613         else
 614                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 615
 616         return len;
 617 }
 618
 619 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 620
 621 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 622                                 struct kobj_attribute *a, char *buf)
 623 {
 624         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 625
 626         return snprintf(buf, PAGE_SIZE, "%pU\n",
 627                         fs_info->fs_devices->metadata_uuid);
 628 }
 629
 630 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 631
 632 static ssize_t btrfs_checksum_show(struct kobject *kobj,
 633                                    struct kobj_attribute *a, char *buf)
 634 {
 635         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 636         u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
 637
 638         return snprintf(buf, PAGE_SIZE, "%s (%s)\n",
 639                         btrfs_super_csum_name(csum_type),
 640                         crypto_shash_driver_name(fs_info->csum_shash));
 641 }
 642
 643 BTRFS_ATTR(, checksum, btrfs_checksum_show);
 644
 645 static const struct attribute *btrfs_attrs[] = {
 646         BTRFS_ATTR_PTR(, label),
 647         BTRFS_ATTR_PTR(, nodesize),
 648         BTRFS_ATTR_PTR(, sectorsize),
 649         BTRFS_ATTR_PTR(, clone_alignment),
 650         BTRFS_ATTR_PTR(, quota_override),
 651         BTRFS_ATTR_PTR(, metadata_uuid),
 652         BTRFS_ATTR_PTR(, checksum),
 653         NULL,
 654 };
 655
 656 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 657 {
 658         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 659
 660         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 661         complete(&fs_devs->kobj_unregister);
 662 }
 663
 664 static struct kobj_type btrfs_ktype = {
 665         .sysfs_ops      = &kobj_sysfs_ops,
 666         .release        = btrfs_release_fsid_kobj,
 667 };
 668
 669 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 670 {
 671         if (kobj->ktype != &btrfs_ktype)
 672                 return NULL;
 673         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 674 }
 675
 676 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 677 {
 678         if (kobj->ktype != &btrfs_ktype)
 679                 return NULL;
 680         return to_fs_devs(kobj)->fs_info;
 681 }
 682
 683 #define NUM_FEATURE_BITS 64
 684 #define BTRFS_FEATURE_NAME_MAX 13
 685 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 686 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 687
 688 static const u64 supported_feature_masks[FEAT_MAX] = {
 689         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 690         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 691         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 692 };
 693
 694 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 695 {
 696         int set;
 697
 698         for (set = 0; set < FEAT_MAX; set++) {
 699                 int i;
 700                 struct attribute *attrs[2];
 701                 struct attribute_group agroup = {
 702                         .name = "features",
 703                         .attrs = attrs,
 704                 };
 705                 u64 features = get_features(fs_info, set);
 706                 features &= ~supported_feature_masks[set];
 707
 708                 if (!features)
 709                         continue;
 710
 711                 attrs[1] = NULL;
 712                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 713                         struct btrfs_feature_attr *fa;
 714
 715                         if (!(features & (1ULL << i)))
 716                                 continue;
 717
 718                         fa = &btrfs_feature_attrs[set][i];
 719                         attrs[0] = &fa->kobj_attr.attr;
 720                         if (add) {
 721                                 int ret;
 722                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 723                                                         &agroup);
 724                                 if (ret)
 725                                         return ret;
 726                         } else
 727                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 728                                                     &agroup);
 729                 }
 730
 731         }
 732         return 0;
 733 }
 734
 735 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 736 {
 737         if (fs_devs->device_dir_kobj) {
 738                 kobject_del(fs_devs->device_dir_kobj);
 739                 kobject_put(fs_devs->device_dir_kobj);
 740                 fs_devs->device_dir_kobj = NULL;
 741         }
 742
 743         if (fs_devs->fsid_kobj.state_initialized) {
 744                 kobject_del(&fs_devs->fsid_kobj);
 745                 kobject_put(&fs_devs->fsid_kobj);
 746                 wait_for_completion(&fs_devs->kobj_unregister);
 747         }
 748 }
 749
 750 /* when fs_devs is NULL it will remove all fsid kobject */
 751 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 752 {
 753         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 754
 755         if (fs_devs) {
 756                 __btrfs_sysfs_remove_fsid(fs_devs);
 757                 return;
 758         }
 759
 760         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 761                 __btrfs_sysfs_remove_fsid(fs_devs);
 762         }
 763 }
 764
 765 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 766 {
 767         btrfs_reset_fs_info_ptr(fs_info);
 768
 769         if (fs_info->space_info_kobj) {
 770                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 771                 kobject_del(fs_info->space_info_kobj);
 772                 kobject_put(fs_info->space_info_kobj);
 773         }
 774         addrm_unknown_feature_attrs(fs_info, false);
 775         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 776         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 777         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 778 }
 779
 780 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
 781         [FEAT_COMPAT]    = "compat",
 782         [FEAT_COMPAT_RO] = "compat_ro",
 783         [FEAT_INCOMPAT]  = "incompat",
 784 };
 785
 786 const char * const btrfs_feature_set_name(enum btrfs_feature_set set)
 787 {
 788         return btrfs_feature_set_names[set];
 789 }
 790
 791 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 792 {
 793         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 794         int len = 0;
 795         int i;
 796         char *str;
 797
 798         str = kmalloc(bufsize, GFP_KERNEL);
 799         if (!str)
 800                 return str;
 801
 802         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 803                 const char *name;
 804
 805                 if (!(flags & (1ULL << i)))
 806                         continue;
 807
 808                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 809                 len += snprintf(str + len, bufsize - len, "%s%s",
 810                                 len ? "," : "", name);
 811         }
 812
 813         return str;
 814 }
 815
 816 static void init_feature_attrs(void)
 817 {
 818         struct btrfs_feature_attr *fa;
 819         int set, i;
 820
 821         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 822                      ARRAY_SIZE(btrfs_feature_attrs));
 823         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 824                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 825
 826         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 827         memset(btrfs_unknown_feature_names, 0,
 828                sizeof(btrfs_unknown_feature_names));
 829
 830         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 831                 struct btrfs_feature_attr *sfa;
 832                 struct attribute *a = btrfs_supported_feature_attrs[i];
 833                 int bit;
 834                 sfa = attr_to_btrfs_feature_attr(a);
 835                 bit = ilog2(sfa->feature_bit);
 836                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 837
 838                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 839         }
 840
 841         for (set = 0; set < FEAT_MAX; set++) {
 842                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 843                         char *name = btrfs_unknown_feature_names[set][i];
 844                         fa = &btrfs_feature_attrs[set][i];
 845
 846                         if (fa->kobj_attr.attr.name)
 847                                 continue;
 848
 849                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 850                                  btrfs_feature_set_names[set], i);
 851
 852                         fa->kobj_attr.attr.name = name;
 853                         fa->kobj_attr.attr.mode = S_IRUGO;
 854                         fa->feature_set = set;
 855                         fa->feature_bit = 1ULL << i;
 856                 }
 857         }
 858 }
 859
 860 /*
 861  * Create a sysfs entry for a given block group type at path
 862  * /sys/fs/btrfs/UUID/allocation/data/TYPE
 863  */
 864 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
 865 {
 866         struct btrfs_fs_info *fs_info = cache->fs_info;
 867         struct btrfs_space_info *space_info = cache->space_info;
 868         struct raid_kobject *rkobj;
 869         const int index = btrfs_bg_flags_to_raid_index(cache->flags);
 870         unsigned int nofs_flag;
 871         int ret;
 872
 873         /*
 874          * Setup a NOFS context because kobject_add(), deep in its call chain,
 875          * does GFP_KERNEL allocations, and we are often called in a context
 876          * where if reclaim is triggered we can deadlock (we are either holding
 877          * a transaction handle or some lock required for a transaction
 878          * commit).
 879          */
 880         nofs_flag = memalloc_nofs_save();
 881
 882         rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
 883         if (!rkobj) {
 884                 memalloc_nofs_restore(nofs_flag);
 885                 btrfs_warn(cache->fs_info,
 886                                 "couldn't alloc memory for raid level kobject");
 887                 return;
 888         }
 889
 890         rkobj->flags = cache->flags;
 891         kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
 892         ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
 893                           btrfs_bg_type_to_raid_name(rkobj->flags));
 894         memalloc_nofs_restore(nofs_flag);
 895         if (ret) {
 896                 kobject_put(&rkobj->kobj);
 897                 btrfs_warn(fs_info,
 898                         "failed to add kobject for block cache, ignoring");
 899                 return;
 900         }
 901
 902         space_info->block_group_kobjs[index] = &rkobj->kobj;
 903 }
 904
 905 /*
 906  * Remove sysfs directories for all block group types of a given space info and
 907  * the space info as well
 908  */
 909 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
 910 {
 911         int i;
 912
 913         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
 914                 struct kobject *kobj;
 915
 916                 kobj = space_info->block_group_kobjs[i];
 917                 space_info->block_group_kobjs[i] = NULL;
 918                 if (kobj) {
 919                         kobject_del(kobj);
 920                         kobject_put(kobj);
 921                 }
 922         }
 923         kobject_del(&space_info->kobj);
 924         kobject_put(&space_info->kobj);
 925 }
 926
 927 static const char *alloc_name(u64 flags)
 928 {
 929         switch (flags) {
 930         case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
 931                 return "mixed";
 932         case BTRFS_BLOCK_GROUP_METADATA:
 933                 return "metadata";
 934         case BTRFS_BLOCK_GROUP_DATA:
 935                 return "data";
 936         case BTRFS_BLOCK_GROUP_SYSTEM:
 937                 return "system";
 938         default:
 939                 WARN_ON(1);
 940                 return "invalid-combination";
 941         };
 942 }
 943
 944 /*
 945  * Create a sysfs entry for a space info type at path
 946  * /sys/fs/btrfs/UUID/allocation/TYPE
 947  */
 948 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
 949                                     struct btrfs_space_info *space_info)
 950 {
 951         int ret;
 952
 953         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
 954                                    fs_info->space_info_kobj, "%s",
 955                                    alloc_name(space_info->flags));
 956         if (ret) {
 957                 kobject_put(&space_info->kobj);
 958                 return ret;
 959         }
 960
 961         return 0;
 962 }
 963
 964 /* when one_device is NULL, it removes all device links */
 965
 966 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 967                 struct btrfs_device *one_device)
 968 {
 969         struct hd_struct *disk;
 970         struct kobject *disk_kobj;
 971
 972         if (!fs_devices->device_dir_kobj)
 973                 return -EINVAL;
 974
 975         if (one_device && one_device->bdev) {
 976                 disk = one_device->bdev->bd_part;
 977                 disk_kobj = &part_to_dev(disk)->kobj;
 978
 979                 sysfs_remove_link(fs_devices->device_dir_kobj,
 980                                                 disk_kobj->name);
 981         }
 982
 983         if (one_device)
 984                 return 0;
 985
 986         list_for_each_entry(one_device,
 987                         &fs_devices->devices, dev_list) {
 988                 if (!one_device->bdev)
 989                         continue;
 990                 disk = one_device->bdev->bd_part;
 991                 disk_kobj = &part_to_dev(disk)->kobj;
 992
 993                 sysfs_remove_link(fs_devices->device_dir_kobj,
 994                                                 disk_kobj->name);
 995         }
 996
 997         return 0;
 998 }
 999
1000 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
1001 {
1002         if (!fs_devs->device_dir_kobj)
1003                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
1004                                                 &fs_devs->fsid_kobj);
1005
1006         if (!fs_devs->device_dir_kobj)
1007                 return -ENOMEM;
1008
1009         return 0;
1010 }
1011
1012 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
1013                                 struct btrfs_device *one_device)
1014 {
1015         int error = 0;
1016         struct btrfs_device *dev;
1017
1018         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
1019                 struct hd_struct *disk;
1020                 struct kobject *disk_kobj;
1021
1022                 if (!dev->bdev)
1023                         continue;
1024
1025                 if (one_device && one_device != dev)
1026                         continue;
1027
1028                 disk = dev->bdev->bd_part;
1029                 disk_kobj = &part_to_dev(disk)->kobj;
1030
1031                 error = sysfs_create_link(fs_devices->device_dir_kobj,
1032                                           disk_kobj, disk_kobj->name);
1033                 if (error)
1034                         break;
1035         }
1036
1037         return error;
1038 }
1039
1040 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1041 {
1042         int ret;
1043
1044         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
1045         if (ret)
1046                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
1047                         action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
1048                         &disk_to_dev(bdev->bd_disk)->kobj);
1049 }
1050
1051 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices,
1052                                     const u8 *fsid)
1053 {
1054         char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
1055
1056         /*
1057          * Sprouting changes fsid of the mounted filesystem, rename the fsid
1058          * directory
1059          */
1060         snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fsid);
1061         if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
1062                 btrfs_warn(fs_devices->fs_info,
1063                                 "sysfs: failed to create fsid for sprout");
1064 }
1065
1066 /* /sys/fs/btrfs/ entry */
1067 static struct kset *btrfs_kset;
1068
1069 /*
1070  * Can be called by the device discovery thread.
1071  * And parent can be specified for seed device
1072  */
1073 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
1074                                 struct kobject *parent)
1075 {
1076         int error;
1077
1078         init_completion(&fs_devs->kobj_unregister);
1079         fs_devs->fsid_kobj.kset = btrfs_kset;
1080         error = kobject_init_and_add(&fs_devs->fsid_kobj,
1081                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
1082         if (error) {
1083                 kobject_put(&fs_devs->fsid_kobj);
1084                 return error;
1085         }
1086
1087         return 0;
1088 }
1089
1090 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
1091 {
1092         int error;
1093         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
1094         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
1095
1096         btrfs_set_fs_info_ptr(fs_info);
1097
1098         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
1099         if (error)
1100                 return error;
1101
1102         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
1103         if (error) {
1104                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
1105                 return error;
1106         }
1107
1108         error = sysfs_create_group(fsid_kobj,
1109                                    &btrfs_feature_attr_group);
1110         if (error)
1111                 goto failure;
1112
1113 #ifdef CONFIG_BTRFS_DEBUG
1114         error = sysfs_create_group(fsid_kobj,
1115                                    &btrfs_debug_feature_attr_group);
1116         if (error)
1117                 goto failure;
1118 #endif
1119
1120         error = addrm_unknown_feature_attrs(fs_info, true);
1121         if (error)
1122                 goto failure;
1123
1124         fs_info->space_info_kobj = kobject_create_and_add("allocation",
1125                                                   fsid_kobj);
1126         if (!fs_info->space_info_kobj) {
1127                 error = -ENOMEM;
1128                 goto failure;
1129         }
1130
1131         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
1132         if (error)
1133                 goto failure;
1134
1135         return 0;
1136 failure:
1137         btrfs_sysfs_remove_mounted(fs_info);
1138         return error;
1139 }
1140
1141
1142 /*
1143  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
1144  * values in superblock. Call after any changes to incompat/compat_ro flags
1145  */
1146 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
1147                 u64 bit, enum btrfs_feature_set set)
1148 {
1149         struct btrfs_fs_devices *fs_devs;
1150         struct kobject *fsid_kobj;
1151         u64 features;
1152         int ret;
1153
1154         if (!fs_info)
1155                 return;
1156
1157         features = get_features(fs_info, set);
1158         ASSERT(bit & supported_feature_masks[set]);
1159
1160         fs_devs = fs_info->fs_devices;
1161         fsid_kobj = &fs_devs->fsid_kobj;
1162
1163         if (!fsid_kobj->state_initialized)
1164                 return;
1165
1166         /*
1167          * FIXME: this is too heavy to update just one value, ideally we'd like
1168          * to use sysfs_update_group but some refactoring is needed first.
1169          */
1170         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1171         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
1172 }
1173
1174 int __init btrfs_init_sysfs(void)
1175 {
1176         int ret;
1177
1178         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
1179         if (!btrfs_kset)
1180                 return -ENOMEM;
1181
1182         init_feature_attrs();
1183         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1184         if (ret)
1185                 goto out2;
1186         ret = sysfs_merge_group(&btrfs_kset->kobj,
1187                                 &btrfs_static_feature_attr_group);
1188         if (ret)
1189                 goto out_remove_group;
1190
1191 #ifdef CONFIG_BTRFS_DEBUG
1192         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1193         if (ret)
1194                 goto out2;
1195 #endif
1196
1197         return 0;
1198
1199 out_remove_group:
1200         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1201 out2:
1202         kset_unregister(btrfs_kset);
1203
1204         return ret;
1205 }
1206
1207 void __cold btrfs_exit_sysfs(void)
1208 {
1209         sysfs_unmerge_group(&btrfs_kset->kobj,
1210                             &btrfs_static_feature_attr_group);
1211         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1212         kset_unregister(btrfs_kset);
1213 }
1214