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 const struct attribute *btrfs_debug_mount_attrs[] = {
 348         NULL,
 349 };
 350
 351 static struct attribute *btrfs_debug_feature_attrs[] = {
 352         NULL
 353 };
 354
 355 static const struct attribute_group btrfs_debug_feature_attr_group = {
 356         .name = "debug",
 357         .attrs = btrfs_debug_feature_attrs,
 358 };
 359
 360 #endif
 361
 362 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 363 {
 364         u64 val;
 365         if (lock)
 366                 spin_lock(lock);
 367         val = *value_ptr;
 368         if (lock)
 369                 spin_unlock(lock);
 370         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 371 }
 372
 373 static ssize_t global_rsv_size_show(struct kobject *kobj,
 374                                     struct kobj_attribute *ka, char *buf)
 375 {
 376         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 377         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 378         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 379 }
 380 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 381
 382 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 383                                         struct kobj_attribute *a, char *buf)
 384 {
 385         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 386         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 387         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 388 }
 389 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 390
 391 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 392 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 393
 394 static ssize_t raid_bytes_show(struct kobject *kobj,
 395                                struct kobj_attribute *attr, char *buf);
 396 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 397 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 398
 399 static ssize_t raid_bytes_show(struct kobject *kobj,
 400                                struct kobj_attribute *attr, char *buf)
 401
 402 {
 403         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 404         struct btrfs_block_group *block_group;
 405         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 406         u64 val = 0;
 407
 408         down_read(&sinfo->groups_sem);
 409         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 410                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 411                         val += block_group->length;
 412                 else
 413                         val += block_group->used;
 414         }
 415         up_read(&sinfo->groups_sem);
 416         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 417 }
 418
 419 static struct attribute *raid_attrs[] = {
 420         BTRFS_ATTR_PTR(raid, total_bytes),
 421         BTRFS_ATTR_PTR(raid, used_bytes),
 422         NULL
 423 };
 424 ATTRIBUTE_GROUPS(raid);
 425
 426 static void release_raid_kobj(struct kobject *kobj)
 427 {
 428         kfree(to_raid_kobj(kobj));
 429 }
 430
 431 static struct kobj_type btrfs_raid_ktype = {
 432         .sysfs_ops = &kobj_sysfs_ops,
 433         .release = release_raid_kobj,
 434         .default_groups = raid_groups,
 435 };
 436
 437 #define SPACE_INFO_ATTR(field)                                          \
 438 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 439                                              struct kobj_attribute *a,  \
 440                                              char *buf)                 \
 441 {                                                                       \
 442         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 443         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 444 }                                                                       \
 445 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 446
 447 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 448                                                        struct kobj_attribute *a,
 449                                                        char *buf)
 450 {
 451         struct btrfs_space_info *sinfo = to_space_info(kobj);
 452         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 453         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 454 }
 455
 456 SPACE_INFO_ATTR(flags);
 457 SPACE_INFO_ATTR(total_bytes);
 458 SPACE_INFO_ATTR(bytes_used);
 459 SPACE_INFO_ATTR(bytes_pinned);
 460 SPACE_INFO_ATTR(bytes_reserved);
 461 SPACE_INFO_ATTR(bytes_may_use);
 462 SPACE_INFO_ATTR(bytes_readonly);
 463 SPACE_INFO_ATTR(disk_used);
 464 SPACE_INFO_ATTR(disk_total);
 465 BTRFS_ATTR(space_info, total_bytes_pinned,
 466            btrfs_space_info_show_total_bytes_pinned);
 467
 468 static struct attribute *space_info_attrs[] = {
 469         BTRFS_ATTR_PTR(space_info, flags),
 470         BTRFS_ATTR_PTR(space_info, total_bytes),
 471         BTRFS_ATTR_PTR(space_info, bytes_used),
 472         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 473         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 474         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 475         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 476         BTRFS_ATTR_PTR(space_info, disk_used),
 477         BTRFS_ATTR_PTR(space_info, disk_total),
 478         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 479         NULL,
 480 };
 481 ATTRIBUTE_GROUPS(space_info);
 482
 483 static void space_info_release(struct kobject *kobj)
 484 {
 485         struct btrfs_space_info *sinfo = to_space_info(kobj);
 486         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 487         kfree(sinfo);
 488 }
 489
 490 static struct kobj_type space_info_ktype = {
 491         .sysfs_ops = &kobj_sysfs_ops,
 492         .release = space_info_release,
 493         .default_groups = space_info_groups,
 494 };
 495
 496 static const struct attribute *allocation_attrs[] = {
 497         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 498         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 499         NULL,
 500 };
 501
 502 static ssize_t btrfs_label_show(struct kobject *kobj,
 503                                 struct kobj_attribute *a, char *buf)
 504 {
 505         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 506         char *label = fs_info->super_copy->label;
 507         ssize_t ret;
 508
 509         spin_lock(&fs_info->super_lock);
 510         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 511         spin_unlock(&fs_info->super_lock);
 512
 513         return ret;
 514 }
 515
 516 static ssize_t btrfs_label_store(struct kobject *kobj,
 517                                  struct kobj_attribute *a,
 518                                  const char *buf, size_t len)
 519 {
 520         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 521         size_t p_len;
 522
 523         if (!fs_info)
 524                 return -EPERM;
 525
 526         if (sb_rdonly(fs_info->sb))
 527                 return -EROFS;
 528
 529         /*
 530          * p_len is the len until the first occurrence of either
 531          * '\n' or '\0'
 532          */
 533         p_len = strcspn(buf, "\n");
 534
 535         if (p_len >= BTRFS_LABEL_SIZE)
 536                 return -EINVAL;
 537
 538         spin_lock(&fs_info->super_lock);
 539         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 540         memcpy(fs_info->super_copy->label, buf, p_len);
 541         spin_unlock(&fs_info->super_lock);
 542
 543         /*
 544          * We don't want to do full transaction commit from inside sysfs
 545          */
 546         btrfs_set_pending(fs_info, COMMIT);
 547         wake_up_process(fs_info->transaction_kthread);
 548
 549         return len;
 550 }
 551 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 552
 553 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 554                                 struct kobj_attribute *a, char *buf)
 555 {
 556         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 557
 558         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 559 }
 560
 561 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 562
 563 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 564                                 struct kobj_attribute *a, char *buf)
 565 {
 566         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 567
 568         return snprintf(buf, PAGE_SIZE, "%u\n",
 569                         fs_info->super_copy->sectorsize);
 570 }
 571
 572 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 573
 574 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 575                                 struct kobj_attribute *a, char *buf)
 576 {
 577         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 578
 579         return snprintf(buf, PAGE_SIZE, "%u\n",
 580                         fs_info->super_copy->sectorsize);
 581 }
 582
 583 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 584
 585 static ssize_t quota_override_show(struct kobject *kobj,
 586                                    struct kobj_attribute *a, char *buf)
 587 {
 588         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 589         int quota_override;
 590
 591         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 592         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 593 }
 594
 595 static ssize_t quota_override_store(struct kobject *kobj,
 596                                     struct kobj_attribute *a,
 597                                     const char *buf, size_t len)
 598 {
 599         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 600         unsigned long knob;
 601         int err;
 602
 603         if (!fs_info)
 604                 return -EPERM;
 605
 606         if (!capable(CAP_SYS_RESOURCE))
 607                 return -EPERM;
 608
 609         err = kstrtoul(buf, 10, &knob);
 610         if (err)
 611                 return err;
 612         if (knob > 1)
 613                 return -EINVAL;
 614
 615         if (knob)
 616                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 617         else
 618                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 619
 620         return len;
 621 }
 622
 623 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 624
 625 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 626                                 struct kobj_attribute *a, char *buf)
 627 {
 628         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 629
 630         return snprintf(buf, PAGE_SIZE, "%pU\n",
 631                         fs_info->fs_devices->metadata_uuid);
 632 }
 633
 634 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 635
 636 static ssize_t btrfs_checksum_show(struct kobject *kobj,
 637                                    struct kobj_attribute *a, char *buf)
 638 {
 639         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 640         u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
 641
 642         return snprintf(buf, PAGE_SIZE, "%s (%s)\n",
 643                         btrfs_super_csum_name(csum_type),
 644                         crypto_shash_driver_name(fs_info->csum_shash));
 645 }
 646
 647 BTRFS_ATTR(, checksum, btrfs_checksum_show);
 648
 649 static const struct attribute *btrfs_attrs[] = {
 650         BTRFS_ATTR_PTR(, label),
 651         BTRFS_ATTR_PTR(, nodesize),
 652         BTRFS_ATTR_PTR(, sectorsize),
 653         BTRFS_ATTR_PTR(, clone_alignment),
 654         BTRFS_ATTR_PTR(, quota_override),
 655         BTRFS_ATTR_PTR(, metadata_uuid),
 656         BTRFS_ATTR_PTR(, checksum),
 657         NULL,
 658 };
 659
 660 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 661 {
 662         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 663
 664         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 665         complete(&fs_devs->kobj_unregister);
 666 }
 667
 668 static struct kobj_type btrfs_ktype = {
 669         .sysfs_ops      = &kobj_sysfs_ops,
 670         .release        = btrfs_release_fsid_kobj,
 671 };
 672
 673 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 674 {
 675         if (kobj->ktype != &btrfs_ktype)
 676                 return NULL;
 677         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 678 }
 679
 680 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 681 {
 682         if (kobj->ktype != &btrfs_ktype)
 683                 return NULL;
 684         return to_fs_devs(kobj)->fs_info;
 685 }
 686
 687 #define NUM_FEATURE_BITS 64
 688 #define BTRFS_FEATURE_NAME_MAX 13
 689 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 690 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 691
 692 static const u64 supported_feature_masks[FEAT_MAX] = {
 693         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 694         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 695         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 696 };
 697
 698 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 699 {
 700         int set;
 701
 702         for (set = 0; set < FEAT_MAX; set++) {
 703                 int i;
 704                 struct attribute *attrs[2];
 705                 struct attribute_group agroup = {
 706                         .name = "features",
 707                         .attrs = attrs,
 708                 };
 709                 u64 features = get_features(fs_info, set);
 710                 features &= ~supported_feature_masks[set];
 711
 712                 if (!features)
 713                         continue;
 714
 715                 attrs[1] = NULL;
 716                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 717                         struct btrfs_feature_attr *fa;
 718
 719                         if (!(features & (1ULL << i)))
 720                                 continue;
 721
 722                         fa = &btrfs_feature_attrs[set][i];
 723                         attrs[0] = &fa->kobj_attr.attr;
 724                         if (add) {
 725                                 int ret;
 726                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 727                                                         &agroup);
 728                                 if (ret)
 729                                         return ret;
 730                         } else
 731                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 732                                                     &agroup);
 733                 }
 734
 735         }
 736         return 0;
 737 }
 738
 739 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 740 {
 741         if (fs_devs->devices_kobj) {
 742                 kobject_del(fs_devs->devices_kobj);
 743                 kobject_put(fs_devs->devices_kobj);
 744                 fs_devs->devices_kobj = NULL;
 745         }
 746
 747         if (fs_devs->fsid_kobj.state_initialized) {
 748                 kobject_del(&fs_devs->fsid_kobj);
 749                 kobject_put(&fs_devs->fsid_kobj);
 750                 wait_for_completion(&fs_devs->kobj_unregister);
 751         }
 752 }
 753
 754 /* when fs_devs is NULL it will remove all fsid kobject */
 755 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 756 {
 757         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 758
 759         if (fs_devs) {
 760                 __btrfs_sysfs_remove_fsid(fs_devs);
 761                 return;
 762         }
 763
 764         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 765                 __btrfs_sysfs_remove_fsid(fs_devs);
 766         }
 767 }
 768
 769 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 770 {
 771         btrfs_reset_fs_info_ptr(fs_info);
 772
 773         if (fs_info->space_info_kobj) {
 774                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 775                 kobject_del(fs_info->space_info_kobj);
 776                 kobject_put(fs_info->space_info_kobj);
 777         }
 778 #ifdef CONFIG_BTRFS_DEBUG
 779         if (fs_info->debug_kobj) {
 780                 sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
 781                 kobject_del(fs_info->debug_kobj);
 782                 kobject_put(fs_info->debug_kobj);
 783         }
 784 #endif
 785         addrm_unknown_feature_attrs(fs_info, false);
 786         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 787         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 788         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 789 }
 790
 791 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
 792         [FEAT_COMPAT]    = "compat",
 793         [FEAT_COMPAT_RO] = "compat_ro",
 794         [FEAT_INCOMPAT]  = "incompat",
 795 };
 796
 797 const char * const btrfs_feature_set_name(enum btrfs_feature_set set)
 798 {
 799         return btrfs_feature_set_names[set];
 800 }
 801
 802 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 803 {
 804         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 805         int len = 0;
 806         int i;
 807         char *str;
 808
 809         str = kmalloc(bufsize, GFP_KERNEL);
 810         if (!str)
 811                 return str;
 812
 813         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 814                 const char *name;
 815
 816                 if (!(flags & (1ULL << i)))
 817                         continue;
 818
 819                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 820                 len += snprintf(str + len, bufsize - len, "%s%s",
 821                                 len ? "," : "", name);
 822         }
 823
 824         return str;
 825 }
 826
 827 static void init_feature_attrs(void)
 828 {
 829         struct btrfs_feature_attr *fa;
 830         int set, i;
 831
 832         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 833                      ARRAY_SIZE(btrfs_feature_attrs));
 834         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 835                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 836
 837         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 838         memset(btrfs_unknown_feature_names, 0,
 839                sizeof(btrfs_unknown_feature_names));
 840
 841         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 842                 struct btrfs_feature_attr *sfa;
 843                 struct attribute *a = btrfs_supported_feature_attrs[i];
 844                 int bit;
 845                 sfa = attr_to_btrfs_feature_attr(a);
 846                 bit = ilog2(sfa->feature_bit);
 847                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 848
 849                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 850         }
 851
 852         for (set = 0; set < FEAT_MAX; set++) {
 853                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 854                         char *name = btrfs_unknown_feature_names[set][i];
 855                         fa = &btrfs_feature_attrs[set][i];
 856
 857                         if (fa->kobj_attr.attr.name)
 858                                 continue;
 859
 860                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 861                                  btrfs_feature_set_names[set], i);
 862
 863                         fa->kobj_attr.attr.name = name;
 864                         fa->kobj_attr.attr.mode = S_IRUGO;
 865                         fa->feature_set = set;
 866                         fa->feature_bit = 1ULL << i;
 867                 }
 868         }
 869 }
 870
 871 /*
 872  * Create a sysfs entry for a given block group type at path
 873  * /sys/fs/btrfs/UUID/allocation/data/TYPE
 874  */
 875 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
 876 {
 877         struct btrfs_fs_info *fs_info = cache->fs_info;
 878         struct btrfs_space_info *space_info = cache->space_info;
 879         struct raid_kobject *rkobj;
 880         const int index = btrfs_bg_flags_to_raid_index(cache->flags);
 881         unsigned int nofs_flag;
 882         int ret;
 883
 884         /*
 885          * Setup a NOFS context because kobject_add(), deep in its call chain,
 886          * does GFP_KERNEL allocations, and we are often called in a context
 887          * where if reclaim is triggered we can deadlock (we are either holding
 888          * a transaction handle or some lock required for a transaction
 889          * commit).
 890          */
 891         nofs_flag = memalloc_nofs_save();
 892
 893         rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
 894         if (!rkobj) {
 895                 memalloc_nofs_restore(nofs_flag);
 896                 btrfs_warn(cache->fs_info,
 897                                 "couldn't alloc memory for raid level kobject");
 898                 return;
 899         }
 900
 901         rkobj->flags = cache->flags;
 902         kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
 903         ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
 904                           btrfs_bg_type_to_raid_name(rkobj->flags));
 905         memalloc_nofs_restore(nofs_flag);
 906         if (ret) {
 907                 kobject_put(&rkobj->kobj);
 908                 btrfs_warn(fs_info,
 909                         "failed to add kobject for block cache, ignoring");
 910                 return;
 911         }
 912
 913         space_info->block_group_kobjs[index] = &rkobj->kobj;
 914 }
 915
 916 /*
 917  * Remove sysfs directories for all block group types of a given space info and
 918  * the space info as well
 919  */
 920 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
 921 {
 922         int i;
 923
 924         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
 925                 struct kobject *kobj;
 926
 927                 kobj = space_info->block_group_kobjs[i];
 928                 space_info->block_group_kobjs[i] = NULL;
 929                 if (kobj) {
 930                         kobject_del(kobj);
 931                         kobject_put(kobj);
 932                 }
 933         }
 934         kobject_del(&space_info->kobj);
 935         kobject_put(&space_info->kobj);
 936 }
 937
 938 static const char *alloc_name(u64 flags)
 939 {
 940         switch (flags) {
 941         case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
 942                 return "mixed";
 943         case BTRFS_BLOCK_GROUP_METADATA:
 944                 return "metadata";
 945         case BTRFS_BLOCK_GROUP_DATA:
 946                 return "data";
 947         case BTRFS_BLOCK_GROUP_SYSTEM:
 948                 return "system";
 949         default:
 950                 WARN_ON(1);
 951                 return "invalid-combination";
 952         };
 953 }
 954
 955 /*
 956  * Create a sysfs entry for a space info type at path
 957  * /sys/fs/btrfs/UUID/allocation/TYPE
 958  */
 959 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
 960                                     struct btrfs_space_info *space_info)
 961 {
 962         int ret;
 963
 964         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
 965                                    fs_info->space_info_kobj, "%s",
 966                                    alloc_name(space_info->flags));
 967         if (ret) {
 968                 kobject_put(&space_info->kobj);
 969                 return ret;
 970         }
 971
 972         return 0;
 973 }
 974
 975 /* when one_device is NULL, it removes all device links */
 976
 977 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 978                 struct btrfs_device *one_device)
 979 {
 980         struct hd_struct *disk;
 981         struct kobject *disk_kobj;
 982
 983         if (!fs_devices->devices_kobj)
 984                 return -EINVAL;
 985
 986         if (one_device && one_device->bdev) {
 987                 disk = one_device->bdev->bd_part;
 988                 disk_kobj = &part_to_dev(disk)->kobj;
 989
 990                 sysfs_remove_link(fs_devices->devices_kobj, disk_kobj->name);
 991         }
 992
 993         if (one_device)
 994                 return 0;
 995
 996         list_for_each_entry(one_device,
 997                         &fs_devices->devices, dev_list) {
 998                 if (!one_device->bdev)
 999                         continue;
1000                 disk = one_device->bdev->bd_part;
1001                 disk_kobj = &part_to_dev(disk)->kobj;
1002
1003                 sysfs_remove_link(fs_devices->devices_kobj, disk_kobj->name);
1004         }
1005
1006         return 0;
1007 }
1008
1009 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
1010                                 struct btrfs_device *one_device)
1011 {
1012         int error = 0;
1013         struct btrfs_device *dev;
1014
1015         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
1016                 struct hd_struct *disk;
1017                 struct kobject *disk_kobj;
1018
1019                 if (!dev->bdev)
1020                         continue;
1021
1022                 if (one_device && one_device != dev)
1023                         continue;
1024
1025                 disk = dev->bdev->bd_part;
1026                 disk_kobj = &part_to_dev(disk)->kobj;
1027
1028                 error = sysfs_create_link(fs_devices->devices_kobj,
1029                                           disk_kobj, disk_kobj->name);
1030                 if (error)
1031                         break;
1032         }
1033
1034         return error;
1035 }
1036
1037 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1038 {
1039         int ret;
1040
1041         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
1042         if (ret)
1043                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
1044                         action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
1045                         &disk_to_dev(bdev->bd_disk)->kobj);
1046 }
1047
1048 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices,
1049                                     const u8 *fsid)
1050 {
1051         char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
1052
1053         /*
1054          * Sprouting changes fsid of the mounted filesystem, rename the fsid
1055          * directory
1056          */
1057         snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fsid);
1058         if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
1059                 btrfs_warn(fs_devices->fs_info,
1060                                 "sysfs: failed to create fsid for sprout");
1061 }
1062
1063 /* /sys/fs/btrfs/ entry */
1064 static struct kset *btrfs_kset;
1065
1066 /*
1067  * Creates:
1068  *              /sys/fs/btrfs/UUID
1069  *
1070  * Can be called by the device discovery thread.
1071  */
1072 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
1073 {
1074         int error;
1075
1076         init_completion(&fs_devs->kobj_unregister);
1077         fs_devs->fsid_kobj.kset = btrfs_kset;
1078         error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
1079                                      "%pU", fs_devs->fsid);
1080         if (error) {
1081                 kobject_put(&fs_devs->fsid_kobj);
1082                 return error;
1083         }
1084
1085         fs_devs->devices_kobj = kobject_create_and_add("devices",
1086                                                        &fs_devs->fsid_kobj);
1087         if (!fs_devs->devices_kobj) {
1088                 btrfs_err(fs_devs->fs_info,
1089                           "failed to init sysfs device interface");
1090                 kobject_put(&fs_devs->fsid_kobj);
1091                 return -ENOMEM;
1092         }
1093
1094         return 0;
1095 }
1096
1097 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
1098 {
1099         int error;
1100         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
1101         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
1102
1103         btrfs_set_fs_info_ptr(fs_info);
1104
1105         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
1106         if (error)
1107                 return error;
1108
1109         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
1110         if (error) {
1111                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
1112                 return error;
1113         }
1114
1115         error = sysfs_create_group(fsid_kobj,
1116                                    &btrfs_feature_attr_group);
1117         if (error)
1118                 goto failure;
1119
1120 #ifdef CONFIG_BTRFS_DEBUG
1121         fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
1122         if (!fs_info->debug_kobj) {
1123                 error = -ENOMEM;
1124                 goto failure;
1125         }
1126
1127         error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1128         if (error)
1129                 goto failure;
1130 #endif
1131
1132         error = addrm_unknown_feature_attrs(fs_info, true);
1133         if (error)
1134                 goto failure;
1135
1136         fs_info->space_info_kobj = kobject_create_and_add("allocation",
1137                                                   fsid_kobj);
1138         if (!fs_info->space_info_kobj) {
1139                 error = -ENOMEM;
1140                 goto failure;
1141         }
1142
1143         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
1144         if (error)
1145                 goto failure;
1146
1147         return 0;
1148 failure:
1149         btrfs_sysfs_remove_mounted(fs_info);
1150         return error;
1151 }
1152
1153
1154 /*
1155  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
1156  * values in superblock. Call after any changes to incompat/compat_ro flags
1157  */
1158 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
1159                 u64 bit, enum btrfs_feature_set set)
1160 {
1161         struct btrfs_fs_devices *fs_devs;
1162         struct kobject *fsid_kobj;
1163         u64 features;
1164         int ret;
1165
1166         if (!fs_info)
1167                 return;
1168
1169         features = get_features(fs_info, set);
1170         ASSERT(bit & supported_feature_masks[set]);
1171
1172         fs_devs = fs_info->fs_devices;
1173         fsid_kobj = &fs_devs->fsid_kobj;
1174
1175         if (!fsid_kobj->state_initialized)
1176                 return;
1177
1178         /*
1179          * FIXME: this is too heavy to update just one value, ideally we'd like
1180          * to use sysfs_update_group but some refactoring is needed first.
1181          */
1182         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1183         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
1184 }
1185
1186 int __init btrfs_init_sysfs(void)
1187 {
1188         int ret;
1189
1190         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
1191         if (!btrfs_kset)
1192                 return -ENOMEM;
1193
1194         init_feature_attrs();
1195         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1196         if (ret)
1197                 goto out2;
1198         ret = sysfs_merge_group(&btrfs_kset->kobj,
1199                                 &btrfs_static_feature_attr_group);
1200         if (ret)
1201                 goto out_remove_group;
1202
1203 #ifdef CONFIG_BTRFS_DEBUG
1204         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1205         if (ret)
1206                 goto out2;
1207 #endif
1208
1209         return 0;
1210
1211 out_remove_group:
1212         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1213 out2:
1214         kset_unregister(btrfs_kset);
1215
1216         return ret;
1217 }
1218
1219 void __cold btrfs_exit_sysfs(void)
1220 {
1221         sysfs_unmerge_group(&btrfs_kset->kobj,
1222                             &btrfs_static_feature_attr_group);
1223         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1224 #ifdef CONFIG_BTRFS_DEBUG
1225         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1226 #endif
1227         kset_unregister(btrfs_kset);
1228 }
1229