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 "discard.h"
  16 #include "disk-io.h"
  17 #include "send.h"
  18 #include "transaction.h"
  19 #include "sysfs.h"
  20 #include "volumes.h"
  21 #include "space-info.h"
  22 #include "block-group.h"
  23 #include "qgroup.h"
  24
  25 struct btrfs_feature_attr {
  26         struct kobj_attribute kobj_attr;
  27         enum btrfs_feature_set feature_set;
  28         u64 feature_bit;
  29 };
  30
  31 /* For raid type sysfs entries */
  32 struct raid_kobject {
  33         u64 flags;
  34         struct kobject kobj;
  35 };
  36
  37 #define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)                   \
  38 {                                                                       \
  39         .attr   = { .name = __stringify(_name), .mode = _mode },        \
  40         .show   = _show,                                                \
  41         .store  = _store,                                               \
  42 }
  43
  44 #define BTRFS_ATTR_RW(_prefix, _name, _show, _store)                    \
  45         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  46                         __INIT_KOBJ_ATTR(_name, 0644, _show, _store)
  47
  48 #define BTRFS_ATTR(_prefix, _name, _show)                               \
  49         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  50                         __INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
  51
  52 #define BTRFS_ATTR_PTR(_prefix, _name)                                  \
  53         (&btrfs_attr_##_prefix##_##_name.attr)
  54
  55 #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
  56 static struct btrfs_feature_attr btrfs_attr_features_##_name = {             \
  57         .kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,                        \
  58                                       btrfs_feature_attr_show,               \
  59                                       btrfs_feature_attr_store),             \
  60         .feature_set    = _feature_set,                                      \
  61         .feature_bit    = _feature_prefix ##_## _feature_bit,                \
  62 }
  63 #define BTRFS_FEAT_ATTR_PTR(_name)                                           \
  64         (&btrfs_attr_features_##_name.kobj_attr.attr)
  65
  66 #define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
  67         BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
  68 #define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
  69         BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
  70 #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
  71         BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)
  72
  73 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  74 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
  75
  76 static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
  77 {
  78         return container_of(a, struct btrfs_feature_attr, kobj_attr);
  79 }
  80
  81 static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
  82 {
  83         return container_of(attr, struct kobj_attribute, attr);
  84 }
  85
  86 static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
  87                 struct attribute *attr)
  88 {
  89         return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
  90 }
  91
  92 static u64 get_features(struct btrfs_fs_info *fs_info,
  93                         enum btrfs_feature_set set)
  94 {
  95         struct btrfs_super_block *disk_super = fs_info->super_copy;
  96         if (set == FEAT_COMPAT)
  97                 return btrfs_super_compat_flags(disk_super);
  98         else if (set == FEAT_COMPAT_RO)
  99                 return btrfs_super_compat_ro_flags(disk_super);
 100         else
 101                 return btrfs_super_incompat_flags(disk_super);
 102 }
 103
 104 static void set_features(struct btrfs_fs_info *fs_info,
 105                          enum btrfs_feature_set set, u64 features)
 106 {
 107         struct btrfs_super_block *disk_super = fs_info->super_copy;
 108         if (set == FEAT_COMPAT)
 109                 btrfs_set_super_compat_flags(disk_super, features);
 110         else if (set == FEAT_COMPAT_RO)
 111                 btrfs_set_super_compat_ro_flags(disk_super, features);
 112         else
 113                 btrfs_set_super_incompat_flags(disk_super, features);
 114 }
 115
 116 static int can_modify_feature(struct btrfs_feature_attr *fa)
 117 {
 118         int val = 0;
 119         u64 set, clear;
 120         switch (fa->feature_set) {
 121         case FEAT_COMPAT:
 122                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 123                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 124                 break;
 125         case FEAT_COMPAT_RO:
 126                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 127                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 128                 break;
 129         case FEAT_INCOMPAT:
 130                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 131                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 132                 break;
 133         default:
 134                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
 135                                 fa->feature_set);
 136                 return 0;
 137         }
 138
 139         if (set & fa->feature_bit)
 140                 val |= 1;
 141         if (clear & fa->feature_bit)
 142                 val |= 2;
 143
 144         return val;
 145 }
 146
 147 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
 148                                        struct kobj_attribute *a, char *buf)
 149 {
 150         int val = 0;
 151         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 152         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 153         if (fs_info) {
 154                 u64 features = get_features(fs_info, fa->feature_set);
 155                 if (features & fa->feature_bit)
 156                         val = 1;
 157         } else
 158                 val = can_modify_feature(fa);
 159
 160         return scnprintf(buf, PAGE_SIZE, "%d\n", val);
 161 }
 162
 163 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 164                                         struct kobj_attribute *a,
 165                                         const char *buf, size_t count)
 166 {
 167         struct btrfs_fs_info *fs_info;
 168         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 169         u64 features, set, clear;
 170         unsigned long val;
 171         int ret;
 172
 173         fs_info = to_fs_info(kobj);
 174         if (!fs_info)
 175                 return -EPERM;
 176
 177         if (sb_rdonly(fs_info->sb))
 178                 return -EROFS;
 179
 180         ret = kstrtoul(skip_spaces(buf), 0, &val);
 181         if (ret)
 182                 return ret;
 183
 184         if (fa->feature_set == FEAT_COMPAT) {
 185                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 186                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 187         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 188                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 189                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 190         } else {
 191                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 192                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 193         }
 194
 195         features = get_features(fs_info, fa->feature_set);
 196
 197         /* Nothing to do */
 198         if ((val && (features & fa->feature_bit)) ||
 199             (!val && !(features & fa->feature_bit)))
 200                 return count;
 201
 202         if ((val && !(set & fa->feature_bit)) ||
 203             (!val && !(clear & fa->feature_bit))) {
 204                 btrfs_info(fs_info,
 205                         "%sabling feature %s on mounted fs is not supported.",
 206                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 207                 return -EPERM;
 208         }
 209
 210         btrfs_info(fs_info, "%s %s feature flag",
 211                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 212
 213         spin_lock(&fs_info->super_lock);
 214         features = get_features(fs_info, fa->feature_set);
 215         if (val)
 216                 features |= fa->feature_bit;
 217         else
 218                 features &= ~fa->feature_bit;
 219         set_features(fs_info, fa->feature_set, features);
 220         spin_unlock(&fs_info->super_lock);
 221
 222         /*
 223          * We don't want to do full transaction commit from inside sysfs
 224          */
 225         btrfs_set_pending(fs_info, COMMIT);
 226         wake_up_process(fs_info->transaction_kthread);
 227
 228         return count;
 229 }
 230
 231 static umode_t btrfs_feature_visible(struct kobject *kobj,
 232                                      struct attribute *attr, int unused)
 233 {
 234         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 235         umode_t mode = attr->mode;
 236
 237         if (fs_info) {
 238                 struct btrfs_feature_attr *fa;
 239                 u64 features;
 240
 241                 fa = attr_to_btrfs_feature_attr(attr);
 242                 features = get_features(fs_info, fa->feature_set);
 243
 244                 if (can_modify_feature(fa))
 245                         mode |= S_IWUSR;
 246                 else if (!(features & fa->feature_bit))
 247                         mode = 0;
 248         }
 249
 250         return mode;
 251 }
 252
 253 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 254 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 255 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 256 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 257 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
 258 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 259 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 260 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 261 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 262 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 263 BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
 264 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 265 BTRFS_FEAT_ATTR_INCOMPAT(raid1c34, RAID1C34);
 266
 267 static struct attribute *btrfs_supported_feature_attrs[] = {
 268         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 269         BTRFS_FEAT_ATTR_PTR(default_subvol),
 270         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 271         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 272         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 273         BTRFS_FEAT_ATTR_PTR(big_metadata),
 274         BTRFS_FEAT_ATTR_PTR(extended_iref),
 275         BTRFS_FEAT_ATTR_PTR(raid56),
 276         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 277         BTRFS_FEAT_ATTR_PTR(no_holes),
 278         BTRFS_FEAT_ATTR_PTR(metadata_uuid),
 279         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 280         BTRFS_FEAT_ATTR_PTR(raid1c34),
 281         NULL
 282 };
 283
 284 /*
 285  * Features which depend on feature bits and may differ between each fs.
 286  *
 287  * /sys/fs/btrfs/features lists all available features of this kernel while
 288  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 289  * can be changed online.
 290  */
 291 static const struct attribute_group btrfs_feature_attr_group = {
 292         .name = "features",
 293         .is_visible = btrfs_feature_visible,
 294         .attrs = btrfs_supported_feature_attrs,
 295 };
 296
 297 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 298                                  struct kobj_attribute *ka, char *buf)
 299 {
 300         return scnprintf(buf, PAGE_SIZE, "0\n");
 301 }
 302 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 303
 304 static ssize_t supported_checksums_show(struct kobject *kobj,
 305                                         struct kobj_attribute *a, char *buf)
 306 {
 307         ssize_t ret = 0;
 308         int i;
 309
 310         for (i = 0; i < btrfs_get_num_csums(); i++) {
 311                 /*
 312                  * This "trick" only works as long as 'enum btrfs_csum_type' has
 313                  * no holes in it
 314                  */
 315                 ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
 316                                 (i == 0 ? "" : " "), btrfs_super_csum_name(i));
 317
 318         }
 319
 320         ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
 321         return ret;
 322 }
 323 BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);
 324
 325 static ssize_t send_stream_version_show(struct kobject *kobj,
 326                                         struct kobj_attribute *ka, char *buf)
 327 {
 328         return snprintf(buf, PAGE_SIZE, "%d\n", BTRFS_SEND_STREAM_VERSION);
 329 }
 330 BTRFS_ATTR(static_feature, send_stream_version, send_stream_version_show);
 331
 332 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 333         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 334         BTRFS_ATTR_PTR(static_feature, supported_checksums),
 335         BTRFS_ATTR_PTR(static_feature, send_stream_version),
 336         NULL
 337 };
 338
 339 /*
 340  * Features which only depend on kernel version.
 341  *
 342  * These are listed in /sys/fs/btrfs/features along with
 343  * btrfs_feature_attr_group
 344  */
 345 static const struct attribute_group btrfs_static_feature_attr_group = {
 346         .name = "features",
 347         .attrs = btrfs_supported_static_feature_attrs,
 348 };
 349
 350 #ifdef CONFIG_BTRFS_DEBUG
 351
 352 /*
 353  * Discard statistics and tunables
 354  */
 355 #define discard_to_fs_info(_kobj)       to_fs_info((_kobj)->parent->parent)
 356
 357 static ssize_t btrfs_discardable_bytes_show(struct kobject *kobj,
 358                                             struct kobj_attribute *a,
 359                                             char *buf)
 360 {
 361         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 362
 363         return scnprintf(buf, PAGE_SIZE, "%lld\n",
 364                         atomic64_read(&fs_info->discard_ctl.discardable_bytes));
 365 }
 366 BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
 367
 368 static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
 369                                               struct kobj_attribute *a,
 370                                               char *buf)
 371 {
 372         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 373
 374         return scnprintf(buf, PAGE_SIZE, "%d\n",
 375                         atomic_read(&fs_info->discard_ctl.discardable_extents));
 376 }
 377 BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
 378
 379 static ssize_t btrfs_discard_bitmap_bytes_show(struct kobject *kobj,
 380                                                struct kobj_attribute *a,
 381                                                char *buf)
 382 {
 383         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 384
 385         return scnprintf(buf, PAGE_SIZE, "%lld\n",
 386                         fs_info->discard_ctl.discard_bitmap_bytes);
 387 }
 388 BTRFS_ATTR(discard, discard_bitmap_bytes, btrfs_discard_bitmap_bytes_show);
 389
 390 static ssize_t btrfs_discard_bytes_saved_show(struct kobject *kobj,
 391                                               struct kobj_attribute *a,
 392                                               char *buf)
 393 {
 394         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 395
 396         return scnprintf(buf, PAGE_SIZE, "%lld\n",
 397                 atomic64_read(&fs_info->discard_ctl.discard_bytes_saved));
 398 }
 399 BTRFS_ATTR(discard, discard_bytes_saved, btrfs_discard_bytes_saved_show);
 400
 401 static ssize_t btrfs_discard_extent_bytes_show(struct kobject *kobj,
 402                                                struct kobj_attribute *a,
 403                                                char *buf)
 404 {
 405         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 406
 407         return scnprintf(buf, PAGE_SIZE, "%lld\n",
 408                         fs_info->discard_ctl.discard_extent_bytes);
 409 }
 410 BTRFS_ATTR(discard, discard_extent_bytes, btrfs_discard_extent_bytes_show);
 411
 412 static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
 413                                              struct kobj_attribute *a,
 414                                              char *buf)
 415 {
 416         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 417
 418         return scnprintf(buf, PAGE_SIZE, "%u\n",
 419                         READ_ONCE(fs_info->discard_ctl.iops_limit));
 420 }
 421
 422 static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
 423                                               struct kobj_attribute *a,
 424                                               const char *buf, size_t len)
 425 {
 426         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 427         struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
 428         u32 iops_limit;
 429         int ret;
 430
 431         ret = kstrtou32(buf, 10, &iops_limit);
 432         if (ret)
 433                 return -EINVAL;
 434
 435         WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
 436
 437         return len;
 438 }
 439 BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
 440               btrfs_discard_iops_limit_store);
 441
 442 static ssize_t btrfs_discard_kbps_limit_show(struct kobject *kobj,
 443                                              struct kobj_attribute *a,
 444                                              char *buf)
 445 {
 446         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 447
 448         return scnprintf(buf, PAGE_SIZE, "%u\n",
 449                         READ_ONCE(fs_info->discard_ctl.kbps_limit));
 450 }
 451
 452 static ssize_t btrfs_discard_kbps_limit_store(struct kobject *kobj,
 453                                               struct kobj_attribute *a,
 454                                               const char *buf, size_t len)
 455 {
 456         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 457         struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
 458         u32 kbps_limit;
 459         int ret;
 460
 461         ret = kstrtou32(buf, 10, &kbps_limit);
 462         if (ret)
 463                 return -EINVAL;
 464
 465         WRITE_ONCE(discard_ctl->kbps_limit, kbps_limit);
 466
 467         return len;
 468 }
 469 BTRFS_ATTR_RW(discard, kbps_limit, btrfs_discard_kbps_limit_show,
 470               btrfs_discard_kbps_limit_store);
 471
 472 static ssize_t btrfs_discard_max_discard_size_show(struct kobject *kobj,
 473                                                    struct kobj_attribute *a,
 474                                                    char *buf)
 475 {
 476         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 477
 478         return scnprintf(buf, PAGE_SIZE, "%llu\n",
 479                         READ_ONCE(fs_info->discard_ctl.max_discard_size));
 480 }
 481
 482 static ssize_t btrfs_discard_max_discard_size_store(struct kobject *kobj,
 483                                                     struct kobj_attribute *a,
 484                                                     const char *buf, size_t len)
 485 {
 486         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 487         struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
 488         u64 max_discard_size;
 489         int ret;
 490
 491         ret = kstrtou64(buf, 10, &max_discard_size);
 492         if (ret)
 493                 return -EINVAL;
 494
 495         WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);
 496
 497         return len;
 498 }
 499 BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
 500               btrfs_discard_max_discard_size_store);
 501
 502 static const struct attribute *discard_debug_attrs[] = {
 503         BTRFS_ATTR_PTR(discard, discardable_bytes),
 504         BTRFS_ATTR_PTR(discard, discardable_extents),
 505         BTRFS_ATTR_PTR(discard, discard_bitmap_bytes),
 506         BTRFS_ATTR_PTR(discard, discard_bytes_saved),
 507         BTRFS_ATTR_PTR(discard, discard_extent_bytes),
 508         BTRFS_ATTR_PTR(discard, iops_limit),
 509         BTRFS_ATTR_PTR(discard, kbps_limit),
 510         BTRFS_ATTR_PTR(discard, max_discard_size),
 511         NULL,
 512 };
 513
 514 /*
 515  * Runtime debugging exported via sysfs
 516  *
 517  * /sys/fs/btrfs/debug - applies to module or all filesystems
 518  * /sys/fs/btrfs/UUID  - applies only to the given filesystem
 519  */
 520 static const struct attribute *btrfs_debug_mount_attrs[] = {
 521         NULL,
 522 };
 523
 524 static struct attribute *btrfs_debug_feature_attrs[] = {
 525         NULL
 526 };
 527
 528 static const struct attribute_group btrfs_debug_feature_attr_group = {
 529         .name = "debug",
 530         .attrs = btrfs_debug_feature_attrs,
 531 };
 532
 533 #endif
 534
 535 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 536 {
 537         u64 val;
 538         if (lock)
 539                 spin_lock(lock);
 540         val = *value_ptr;
 541         if (lock)
 542                 spin_unlock(lock);
 543         return scnprintf(buf, PAGE_SIZE, "%llu\n", val);
 544 }
 545
 546 static ssize_t global_rsv_size_show(struct kobject *kobj,
 547                                     struct kobj_attribute *ka, char *buf)
 548 {
 549         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 550         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 551         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 552 }
 553 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 554
 555 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 556                                         struct kobj_attribute *a, char *buf)
 557 {
 558         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 559         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 560         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 561 }
 562 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 563
 564 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 565 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 566
 567 static ssize_t raid_bytes_show(struct kobject *kobj,
 568                                struct kobj_attribute *attr, char *buf);
 569 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 570 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 571
 572 static ssize_t raid_bytes_show(struct kobject *kobj,
 573                                struct kobj_attribute *attr, char *buf)
 574
 575 {
 576         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 577         struct btrfs_block_group *block_group;
 578         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 579         u64 val = 0;
 580
 581         down_read(&sinfo->groups_sem);
 582         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 583                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 584                         val += block_group->length;
 585                 else
 586                         val += block_group->used;
 587         }
 588         up_read(&sinfo->groups_sem);
 589         return scnprintf(buf, PAGE_SIZE, "%llu\n", val);
 590 }
 591
 592 static struct attribute *raid_attrs[] = {
 593         BTRFS_ATTR_PTR(raid, total_bytes),
 594         BTRFS_ATTR_PTR(raid, used_bytes),
 595         NULL
 596 };
 597 ATTRIBUTE_GROUPS(raid);
 598
 599 static void release_raid_kobj(struct kobject *kobj)
 600 {
 601         kfree(to_raid_kobj(kobj));
 602 }
 603
 604 static struct kobj_type btrfs_raid_ktype = {
 605         .sysfs_ops = &kobj_sysfs_ops,
 606         .release = release_raid_kobj,
 607         .default_groups = raid_groups,
 608 };
 609
 610 #define SPACE_INFO_ATTR(field)                                          \
 611 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 612                                              struct kobj_attribute *a,  \
 613                                              char *buf)                 \
 614 {                                                                       \
 615         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 616         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 617 }                                                                       \
 618 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 619
 620 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 621                                                        struct kobj_attribute *a,
 622                                                        char *buf)
 623 {
 624         struct btrfs_space_info *sinfo = to_space_info(kobj);
 625         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 626         return scnprintf(buf, PAGE_SIZE, "%lld\n", val);
 627 }
 628
 629 SPACE_INFO_ATTR(flags);
 630 SPACE_INFO_ATTR(total_bytes);
 631 SPACE_INFO_ATTR(bytes_used);
 632 SPACE_INFO_ATTR(bytes_pinned);
 633 SPACE_INFO_ATTR(bytes_reserved);
 634 SPACE_INFO_ATTR(bytes_may_use);
 635 SPACE_INFO_ATTR(bytes_readonly);
 636 SPACE_INFO_ATTR(disk_used);
 637 SPACE_INFO_ATTR(disk_total);
 638 BTRFS_ATTR(space_info, total_bytes_pinned,
 639            btrfs_space_info_show_total_bytes_pinned);
 640
 641 static struct attribute *space_info_attrs[] = {
 642         BTRFS_ATTR_PTR(space_info, flags),
 643         BTRFS_ATTR_PTR(space_info, total_bytes),
 644         BTRFS_ATTR_PTR(space_info, bytes_used),
 645         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 646         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 647         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 648         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 649         BTRFS_ATTR_PTR(space_info, disk_used),
 650         BTRFS_ATTR_PTR(space_info, disk_total),
 651         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 652         NULL,
 653 };
 654 ATTRIBUTE_GROUPS(space_info);
 655
 656 static void space_info_release(struct kobject *kobj)
 657 {
 658         struct btrfs_space_info *sinfo = to_space_info(kobj);
 659         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 660         kfree(sinfo);
 661 }
 662
 663 static struct kobj_type space_info_ktype = {
 664         .sysfs_ops = &kobj_sysfs_ops,
 665         .release = space_info_release,
 666         .default_groups = space_info_groups,
 667 };
 668
 669 static const struct attribute *allocation_attrs[] = {
 670         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 671         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 672         NULL,
 673 };
 674
 675 static ssize_t btrfs_label_show(struct kobject *kobj,
 676                                 struct kobj_attribute *a, char *buf)
 677 {
 678         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 679         char *label = fs_info->super_copy->label;
 680         ssize_t ret;
 681
 682         spin_lock(&fs_info->super_lock);
 683         ret = scnprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 684         spin_unlock(&fs_info->super_lock);
 685
 686         return ret;
 687 }
 688
 689 static ssize_t btrfs_label_store(struct kobject *kobj,
 690                                  struct kobj_attribute *a,
 691                                  const char *buf, size_t len)
 692 {
 693         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 694         size_t p_len;
 695
 696         if (!fs_info)
 697                 return -EPERM;
 698
 699         if (sb_rdonly(fs_info->sb))
 700                 return -EROFS;
 701
 702         /*
 703          * p_len is the len until the first occurrence of either
 704          * '\n' or '\0'
 705          */
 706         p_len = strcspn(buf, "\n");
 707
 708         if (p_len >= BTRFS_LABEL_SIZE)
 709                 return -EINVAL;
 710
 711         spin_lock(&fs_info->super_lock);
 712         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 713         memcpy(fs_info->super_copy->label, buf, p_len);
 714         spin_unlock(&fs_info->super_lock);
 715
 716         /*
 717          * We don't want to do full transaction commit from inside sysfs
 718          */
 719         btrfs_set_pending(fs_info, COMMIT);
 720         wake_up_process(fs_info->transaction_kthread);
 721
 722         return len;
 723 }
 724 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 725
 726 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 727                                 struct kobj_attribute *a, char *buf)
 728 {
 729         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 730
 731         return scnprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 732 }
 733
 734 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 735
 736 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 737                                 struct kobj_attribute *a, char *buf)
 738 {
 739         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 740
 741         return scnprintf(buf, PAGE_SIZE, "%u\n",
 742                          fs_info->super_copy->sectorsize);
 743 }
 744
 745 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 746
 747 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 748                                 struct kobj_attribute *a, char *buf)
 749 {
 750         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 751
 752         return scnprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 753 }
 754
 755 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 756
 757 static ssize_t quota_override_show(struct kobject *kobj,
 758                                    struct kobj_attribute *a, char *buf)
 759 {
 760         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 761         int quota_override;
 762
 763         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 764         return scnprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 765 }
 766
 767 static ssize_t quota_override_store(struct kobject *kobj,
 768                                     struct kobj_attribute *a,
 769                                     const char *buf, size_t len)
 770 {
 771         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 772         unsigned long knob;
 773         int err;
 774
 775         if (!fs_info)
 776                 return -EPERM;
 777
 778         if (!capable(CAP_SYS_RESOURCE))
 779                 return -EPERM;
 780
 781         err = kstrtoul(buf, 10, &knob);
 782         if (err)
 783                 return err;
 784         if (knob > 1)
 785                 return -EINVAL;
 786
 787         if (knob)
 788                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 789         else
 790                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 791
 792         return len;
 793 }
 794
 795 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 796
 797 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 798                                 struct kobj_attribute *a, char *buf)
 799 {
 800         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 801
 802         return scnprintf(buf, PAGE_SIZE, "%pU\n",
 803                         fs_info->fs_devices->metadata_uuid);
 804 }
 805
 806 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 807
 808 static ssize_t btrfs_checksum_show(struct kobject *kobj,
 809                                    struct kobj_attribute *a, char *buf)
 810 {
 811         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 812         u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
 813
 814         return scnprintf(buf, PAGE_SIZE, "%s (%s)\n",
 815                         btrfs_super_csum_name(csum_type),
 816                         crypto_shash_driver_name(fs_info->csum_shash));
 817 }
 818
 819 BTRFS_ATTR(, checksum, btrfs_checksum_show);
 820
 821 static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
 822                 struct kobj_attribute *a, char *buf)
 823 {
 824         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 825         const char *str;
 826
 827         switch (READ_ONCE(fs_info->exclusive_operation)) {
 828                 case  BTRFS_EXCLOP_NONE:
 829                         str = "none\n";
 830                         break;
 831                 case BTRFS_EXCLOP_BALANCE:
 832                         str = "balance\n";
 833                         break;
 834                 case BTRFS_EXCLOP_DEV_ADD:
 835                         str = "device add\n";
 836                         break;
 837                 case BTRFS_EXCLOP_DEV_REMOVE:
 838                         str = "device remove\n";
 839                         break;
 840                 case BTRFS_EXCLOP_DEV_REPLACE:
 841                         str = "device replace\n";
 842                         break;
 843                 case BTRFS_EXCLOP_RESIZE:
 844                         str = "resize\n";
 845                         break;
 846                 case BTRFS_EXCLOP_SWAP_ACTIVATE:
 847                         str = "swap activate\n";
 848                         break;
 849                 default:
 850                         str = "UNKNOWN\n";
 851                         break;
 852         }
 853         return scnprintf(buf, PAGE_SIZE, "%s", str);
 854 }
 855 BTRFS_ATTR(, exclusive_operation, btrfs_exclusive_operation_show);
 856
 857 static const struct attribute *btrfs_attrs[] = {
 858         BTRFS_ATTR_PTR(, label),
 859         BTRFS_ATTR_PTR(, nodesize),
 860         BTRFS_ATTR_PTR(, sectorsize),
 861         BTRFS_ATTR_PTR(, clone_alignment),
 862         BTRFS_ATTR_PTR(, quota_override),
 863         BTRFS_ATTR_PTR(, metadata_uuid),
 864         BTRFS_ATTR_PTR(, checksum),
 865         BTRFS_ATTR_PTR(, exclusive_operation),
 866         NULL,
 867 };
 868
 869 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 870 {
 871         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 872
 873         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 874         complete(&fs_devs->kobj_unregister);
 875 }
 876
 877 static struct kobj_type btrfs_ktype = {
 878         .sysfs_ops      = &kobj_sysfs_ops,
 879         .release        = btrfs_release_fsid_kobj,
 880 };
 881
 882 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 883 {
 884         if (kobj->ktype != &btrfs_ktype)
 885                 return NULL;
 886         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 887 }
 888
 889 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 890 {
 891         if (kobj->ktype != &btrfs_ktype)
 892                 return NULL;
 893         return to_fs_devs(kobj)->fs_info;
 894 }
 895
 896 #define NUM_FEATURE_BITS 64
 897 #define BTRFS_FEATURE_NAME_MAX 13
 898 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 899 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 900
 901 static const u64 supported_feature_masks[FEAT_MAX] = {
 902         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 903         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 904         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 905 };
 906
 907 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 908 {
 909         int set;
 910
 911         for (set = 0; set < FEAT_MAX; set++) {
 912                 int i;
 913                 struct attribute *attrs[2];
 914                 struct attribute_group agroup = {
 915                         .name = "features",
 916                         .attrs = attrs,
 917                 };
 918                 u64 features = get_features(fs_info, set);
 919                 features &= ~supported_feature_masks[set];
 920
 921                 if (!features)
 922                         continue;
 923
 924                 attrs[1] = NULL;
 925                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 926                         struct btrfs_feature_attr *fa;
 927
 928                         if (!(features & (1ULL << i)))
 929                                 continue;
 930
 931                         fa = &btrfs_feature_attrs[set][i];
 932                         attrs[0] = &fa->kobj_attr.attr;
 933                         if (add) {
 934                                 int ret;
 935                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 936                                                         &agroup);
 937                                 if (ret)
 938                                         return ret;
 939                         } else
 940                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 941                                                     &agroup);
 942                 }
 943
 944         }
 945         return 0;
 946 }
 947
 948 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 949 {
 950         if (fs_devs->devinfo_kobj) {
 951                 kobject_del(fs_devs->devinfo_kobj);
 952                 kobject_put(fs_devs->devinfo_kobj);
 953                 fs_devs->devinfo_kobj = NULL;
 954         }
 955
 956         if (fs_devs->devices_kobj) {
 957                 kobject_del(fs_devs->devices_kobj);
 958                 kobject_put(fs_devs->devices_kobj);
 959                 fs_devs->devices_kobj = NULL;
 960         }
 961
 962         if (fs_devs->fsid_kobj.state_initialized) {
 963                 kobject_del(&fs_devs->fsid_kobj);
 964                 kobject_put(&fs_devs->fsid_kobj);
 965                 wait_for_completion(&fs_devs->kobj_unregister);
 966         }
 967 }
 968
 969 /* when fs_devs is NULL it will remove all fsid kobject */
 970 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 971 {
 972         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 973
 974         if (fs_devs) {
 975                 __btrfs_sysfs_remove_fsid(fs_devs);
 976                 return;
 977         }
 978
 979         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 980                 __btrfs_sysfs_remove_fsid(fs_devs);
 981         }
 982 }
 983
 984 static void btrfs_sysfs_remove_fs_devices(struct btrfs_fs_devices *fs_devices)
 985 {
 986         struct btrfs_device *device;
 987         struct btrfs_fs_devices *seed;
 988
 989         list_for_each_entry(device, &fs_devices->devices, dev_list)
 990                 btrfs_sysfs_remove_device(device);
 991
 992         list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
 993                 list_for_each_entry(device, &seed->devices, dev_list)
 994                         btrfs_sysfs_remove_device(device);
 995         }
 996 }
 997
 998 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 999 {
1000         struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1001
1002         sysfs_remove_link(fsid_kobj, "bdi");
1003
1004         if (fs_info->space_info_kobj) {
1005                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
1006                 kobject_del(fs_info->space_info_kobj);
1007                 kobject_put(fs_info->space_info_kobj);
1008         }
1009 #ifdef CONFIG_BTRFS_DEBUG
1010         if (fs_info->discard_debug_kobj) {
1011                 sysfs_remove_files(fs_info->discard_debug_kobj,
1012                                    discard_debug_attrs);
1013                 kobject_del(fs_info->discard_debug_kobj);
1014                 kobject_put(fs_info->discard_debug_kobj);
1015         }
1016         if (fs_info->debug_kobj) {
1017                 sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1018                 kobject_del(fs_info->debug_kobj);
1019                 kobject_put(fs_info->debug_kobj);
1020         }
1021 #endif
1022         addrm_unknown_feature_attrs(fs_info, false);
1023         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1024         sysfs_remove_files(fsid_kobj, btrfs_attrs);
1025         btrfs_sysfs_remove_fs_devices(fs_info->fs_devices);
1026 }
1027
1028 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
1029         [FEAT_COMPAT]    = "compat",
1030         [FEAT_COMPAT_RO] = "compat_ro",
1031         [FEAT_INCOMPAT]  = "incompat",
1032 };
1033
1034 const char *btrfs_feature_set_name(enum btrfs_feature_set set)
1035 {
1036         return btrfs_feature_set_names[set];
1037 }
1038
1039 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
1040 {
1041         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
1042         int len = 0;
1043         int i;
1044         char *str;
1045
1046         str = kmalloc(bufsize, GFP_KERNEL);
1047         if (!str)
1048                 return str;
1049
1050         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1051                 const char *name;
1052
1053                 if (!(flags & (1ULL << i)))
1054                         continue;
1055
1056                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
1057                 len += scnprintf(str + len, bufsize - len, "%s%s",
1058                                 len ? "," : "", name);
1059         }
1060
1061         return str;
1062 }
1063
1064 static void init_feature_attrs(void)
1065 {
1066         struct btrfs_feature_attr *fa;
1067         int set, i;
1068
1069         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
1070                      ARRAY_SIZE(btrfs_feature_attrs));
1071         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
1072                      ARRAY_SIZE(btrfs_feature_attrs[0]));
1073
1074         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
1075         memset(btrfs_unknown_feature_names, 0,
1076                sizeof(btrfs_unknown_feature_names));
1077
1078         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
1079                 struct btrfs_feature_attr *sfa;
1080                 struct attribute *a = btrfs_supported_feature_attrs[i];
1081                 int bit;
1082                 sfa = attr_to_btrfs_feature_attr(a);
1083                 bit = ilog2(sfa->feature_bit);
1084                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
1085
1086                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
1087         }
1088
1089         for (set = 0; set < FEAT_MAX; set++) {
1090                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1091                         char *name = btrfs_unknown_feature_names[set][i];
1092                         fa = &btrfs_feature_attrs[set][i];
1093
1094                         if (fa->kobj_attr.attr.name)
1095                                 continue;
1096
1097                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
1098                                  btrfs_feature_set_names[set], i);
1099
1100                         fa->kobj_attr.attr.name = name;
1101                         fa->kobj_attr.attr.mode = S_IRUGO;
1102                         fa->feature_set = set;
1103                         fa->feature_bit = 1ULL << i;
1104                 }
1105         }
1106 }
1107
1108 /*
1109  * Create a sysfs entry for a given block group type at path
1110  * /sys/fs/btrfs/UUID/allocation/data/TYPE
1111  */
1112 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
1113 {
1114         struct btrfs_fs_info *fs_info = cache->fs_info;
1115         struct btrfs_space_info *space_info = cache->space_info;
1116         struct raid_kobject *rkobj;
1117         const int index = btrfs_bg_flags_to_raid_index(cache->flags);
1118         unsigned int nofs_flag;
1119         int ret;
1120
1121         /*
1122          * Setup a NOFS context because kobject_add(), deep in its call chain,
1123          * does GFP_KERNEL allocations, and we are often called in a context
1124          * where if reclaim is triggered we can deadlock (we are either holding
1125          * a transaction handle or some lock required for a transaction
1126          * commit).
1127          */
1128         nofs_flag = memalloc_nofs_save();
1129
1130         rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
1131         if (!rkobj) {
1132                 memalloc_nofs_restore(nofs_flag);
1133                 btrfs_warn(cache->fs_info,
1134                                 "couldn't alloc memory for raid level kobject");
1135                 return;
1136         }
1137
1138         rkobj->flags = cache->flags;
1139         kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
1140
1141         /*
1142          * We call this either on mount, or if we've created a block group for a
1143          * new index type while running (i.e. when restriping).  The running
1144          * case is tricky because we could race with other threads, so we need
1145          * to have this check to make sure we didn't already init the kobject.
1146          *
1147          * We don't have to protect on the free side because it only happens on
1148          * unmount.
1149          */
1150         spin_lock(&space_info->lock);
1151         if (space_info->block_group_kobjs[index]) {
1152                 spin_unlock(&space_info->lock);
1153                 kobject_put(&rkobj->kobj);
1154                 return;
1155         } else {
1156                 space_info->block_group_kobjs[index] = &rkobj->kobj;
1157         }
1158         spin_unlock(&space_info->lock);
1159
1160         ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
1161                           btrfs_bg_type_to_raid_name(rkobj->flags));
1162         memalloc_nofs_restore(nofs_flag);
1163         if (ret) {
1164                 spin_lock(&space_info->lock);
1165                 space_info->block_group_kobjs[index] = NULL;
1166                 spin_unlock(&space_info->lock);
1167                 kobject_put(&rkobj->kobj);
1168                 btrfs_warn(fs_info,
1169                         "failed to add kobject for block cache, ignoring");
1170                 return;
1171         }
1172 }
1173
1174 /*
1175  * Remove sysfs directories for all block group types of a given space info and
1176  * the space info as well
1177  */
1178 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
1179 {
1180         int i;
1181
1182         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1183                 struct kobject *kobj;
1184
1185                 kobj = space_info->block_group_kobjs[i];
1186                 space_info->block_group_kobjs[i] = NULL;
1187                 if (kobj) {
1188                         kobject_del(kobj);
1189                         kobject_put(kobj);
1190                 }
1191         }
1192         kobject_del(&space_info->kobj);
1193         kobject_put(&space_info->kobj);
1194 }
1195
1196 static const char *alloc_name(u64 flags)
1197 {
1198         switch (flags) {
1199         case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
1200                 return "mixed";
1201         case BTRFS_BLOCK_GROUP_METADATA:
1202                 return "metadata";
1203         case BTRFS_BLOCK_GROUP_DATA:
1204                 return "data";
1205         case BTRFS_BLOCK_GROUP_SYSTEM:
1206                 return "system";
1207         default:
1208                 WARN_ON(1);
1209                 return "invalid-combination";
1210         };
1211 }
1212
1213 /*
1214  * Create a sysfs entry for a space info type at path
1215  * /sys/fs/btrfs/UUID/allocation/TYPE
1216  */
1217 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
1218                                     struct btrfs_space_info *space_info)
1219 {
1220         int ret;
1221
1222         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
1223                                    fs_info->space_info_kobj, "%s",
1224                                    alloc_name(space_info->flags));
1225         if (ret) {
1226                 kobject_put(&space_info->kobj);
1227                 return ret;
1228         }
1229
1230         return 0;
1231 }
1232
1233 void btrfs_sysfs_remove_device(struct btrfs_device *device)
1234 {
1235         struct hd_struct *disk;
1236         struct kobject *disk_kobj;
1237         struct kobject *devices_kobj;
1238
1239         /*
1240          * Seed fs_devices devices_kobj aren't used, fetch kobject from the
1241          * fs_info::fs_devices.
1242          */
1243         devices_kobj = device->fs_info->fs_devices->devices_kobj;
1244         ASSERT(devices_kobj);
1245
1246         if (device->bdev) {
1247                 disk = device->bdev->bd_part;
1248                 disk_kobj = &part_to_dev(disk)->kobj;
1249                 sysfs_remove_link(devices_kobj, disk_kobj->name);
1250         }
1251
1252         if (device->devid_kobj.state_initialized) {
1253                 kobject_del(&device->devid_kobj);
1254                 kobject_put(&device->devid_kobj);
1255                 wait_for_completion(&device->kobj_unregister);
1256         }
1257 }
1258
1259 static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj,
1260                                                  struct kobj_attribute *a,
1261                                                  char *buf)
1262 {
1263         int val;
1264         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1265                                                    devid_kobj);
1266
1267         val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
1268
1269         return scnprintf(buf, PAGE_SIZE, "%d\n", val);
1270 }
1271 BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show);
1272
1273 static ssize_t btrfs_devinfo_missing_show(struct kobject *kobj,
1274                                         struct kobj_attribute *a, char *buf)
1275 {
1276         int val;
1277         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1278                                                    devid_kobj);
1279
1280         val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
1281
1282         return scnprintf(buf, PAGE_SIZE, "%d\n", val);
1283 }
1284 BTRFS_ATTR(devid, missing, btrfs_devinfo_missing_show);
1285
1286 static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj,
1287                                                  struct kobj_attribute *a,
1288                                                  char *buf)
1289 {
1290         int val;
1291         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1292                                                    devid_kobj);
1293
1294         val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
1295
1296         return scnprintf(buf, PAGE_SIZE, "%d\n", val);
1297 }
1298 BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show);
1299
1300 static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj,
1301                                             struct kobj_attribute *a, char *buf)
1302 {
1303         int val;
1304         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1305                                                    devid_kobj);
1306
1307         val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
1308
1309         return scnprintf(buf, PAGE_SIZE, "%d\n", val);
1310 }
1311 BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show);
1312
1313 static struct attribute *devid_attrs[] = {
1314         BTRFS_ATTR_PTR(devid, in_fs_metadata),
1315         BTRFS_ATTR_PTR(devid, missing),
1316         BTRFS_ATTR_PTR(devid, replace_target),
1317         BTRFS_ATTR_PTR(devid, writeable),
1318         NULL
1319 };
1320 ATTRIBUTE_GROUPS(devid);
1321
1322 static void btrfs_release_devid_kobj(struct kobject *kobj)
1323 {
1324         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1325                                                    devid_kobj);
1326
1327         memset(&device->devid_kobj, 0, sizeof(struct kobject));
1328         complete(&device->kobj_unregister);
1329 }
1330
1331 static struct kobj_type devid_ktype = {
1332         .sysfs_ops      = &kobj_sysfs_ops,
1333         .default_groups = devid_groups,
1334         .release        = btrfs_release_devid_kobj,
1335 };
1336
1337 int btrfs_sysfs_add_device(struct btrfs_device *device)
1338 {
1339         int ret;
1340         unsigned int nofs_flag;
1341         struct kobject *devices_kobj;
1342         struct kobject *devinfo_kobj;
1343
1344         /*
1345          * Make sure we use the fs_info::fs_devices to fetch the kobjects even
1346          * for the seed fs_devices
1347          */
1348         devices_kobj = device->fs_info->fs_devices->devices_kobj;
1349         devinfo_kobj = device->fs_info->fs_devices->devinfo_kobj;
1350         ASSERT(devices_kobj);
1351         ASSERT(devinfo_kobj);
1352
1353         nofs_flag = memalloc_nofs_save();
1354
1355         if (device->bdev) {
1356                 struct hd_struct *disk;
1357                 struct kobject *disk_kobj;
1358
1359                 disk = device->bdev->bd_part;
1360                 disk_kobj = &part_to_dev(disk)->kobj;
1361
1362                 ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
1363                 if (ret) {
1364                         btrfs_warn(device->fs_info,
1365                                 "creating sysfs device link for devid %llu failed: %d",
1366                                 device->devid, ret);
1367                         goto out;
1368                 }
1369         }
1370
1371         init_completion(&device->kobj_unregister);
1372         ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype,
1373                                    devinfo_kobj, "%llu", device->devid);
1374         if (ret) {
1375                 kobject_put(&device->devid_kobj);
1376                 btrfs_warn(device->fs_info,
1377                            "devinfo init for devid %llu failed: %d",
1378                            device->devid, ret);
1379         }
1380
1381 out:
1382         memalloc_nofs_restore(nofs_flag);
1383         return ret;
1384 }
1385
1386 static int btrfs_sysfs_add_fs_devices(struct btrfs_fs_devices *fs_devices)
1387 {
1388         int ret;
1389         struct btrfs_device *device;
1390         struct btrfs_fs_devices *seed;
1391
1392         list_for_each_entry(device, &fs_devices->devices, dev_list) {
1393                 ret = btrfs_sysfs_add_device(device);
1394                 if (ret)
1395                         goto fail;
1396         }
1397
1398         list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1399                 list_for_each_entry(device, &seed->devices, dev_list) {
1400                         ret = btrfs_sysfs_add_device(device);
1401                         if (ret)
1402                                 goto fail;
1403                 }
1404         }
1405
1406         return 0;
1407
1408 fail:
1409         btrfs_sysfs_remove_fs_devices(fs_devices);
1410         return ret;
1411 }
1412
1413 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1414 {
1415         int ret;
1416
1417         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
1418         if (ret)
1419                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
1420                         action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
1421                         &disk_to_dev(bdev->bd_disk)->kobj);
1422 }
1423
1424 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices)
1425
1426 {
1427         char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
1428
1429         /*
1430          * Sprouting changes fsid of the mounted filesystem, rename the fsid
1431          * directory
1432          */
1433         snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fs_devices->fsid);
1434         if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
1435                 btrfs_warn(fs_devices->fs_info,
1436                                 "sysfs: failed to create fsid for sprout");
1437 }
1438
1439 void btrfs_sysfs_update_devid(struct btrfs_device *device)
1440 {
1441         char tmp[24];
1442
1443         snprintf(tmp, sizeof(tmp), "%llu", device->devid);
1444
1445         if (kobject_rename(&device->devid_kobj, tmp))
1446                 btrfs_warn(device->fs_devices->fs_info,
1447                            "sysfs: failed to update devid for %llu",
1448                            device->devid);
1449 }
1450
1451 /* /sys/fs/btrfs/ entry */
1452 static struct kset *btrfs_kset;
1453
1454 /*
1455  * Creates:
1456  *              /sys/fs/btrfs/UUID
1457  *
1458  * Can be called by the device discovery thread.
1459  */
1460 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
1461 {
1462         int error;
1463
1464         init_completion(&fs_devs->kobj_unregister);
1465         fs_devs->fsid_kobj.kset = btrfs_kset;
1466         error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
1467                                      "%pU", fs_devs->fsid);
1468         if (error) {
1469                 kobject_put(&fs_devs->fsid_kobj);
1470                 return error;
1471         }
1472
1473         fs_devs->devices_kobj = kobject_create_and_add("devices",
1474                                                        &fs_devs->fsid_kobj);
1475         if (!fs_devs->devices_kobj) {
1476                 btrfs_err(fs_devs->fs_info,
1477                           "failed to init sysfs device interface");
1478                 btrfs_sysfs_remove_fsid(fs_devs);
1479                 return -ENOMEM;
1480         }
1481
1482         fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
1483                                                        &fs_devs->fsid_kobj);
1484         if (!fs_devs->devinfo_kobj) {
1485                 btrfs_err(fs_devs->fs_info,
1486                           "failed to init sysfs devinfo kobject");
1487                 btrfs_sysfs_remove_fsid(fs_devs);
1488                 return -ENOMEM;
1489         }
1490
1491         return 0;
1492 }
1493
1494 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
1495 {
1496         int error;
1497         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
1498         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
1499
1500         error = btrfs_sysfs_add_fs_devices(fs_devs);
1501         if (error)
1502                 return error;
1503
1504         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
1505         if (error) {
1506                 btrfs_sysfs_remove_fs_devices(fs_devs);
1507                 return error;
1508         }
1509
1510         error = sysfs_create_group(fsid_kobj,
1511                                    &btrfs_feature_attr_group);
1512         if (error)
1513                 goto failure;
1514
1515 #ifdef CONFIG_BTRFS_DEBUG
1516         fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
1517         if (!fs_info->debug_kobj) {
1518                 error = -ENOMEM;
1519                 goto failure;
1520         }
1521
1522         error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1523         if (error)
1524                 goto failure;
1525
1526         /* Discard directory */
1527         fs_info->discard_debug_kobj = kobject_create_and_add("discard",
1528                                                      fs_info->debug_kobj);
1529         if (!fs_info->discard_debug_kobj) {
1530                 error = -ENOMEM;
1531                 goto failure;
1532         }
1533
1534         error = sysfs_create_files(fs_info->discard_debug_kobj,
1535                                    discard_debug_attrs);
1536         if (error)
1537                 goto failure;
1538 #endif
1539
1540         error = addrm_unknown_feature_attrs(fs_info, true);
1541         if (error)
1542                 goto failure;
1543
1544         error = sysfs_create_link(fsid_kobj, &fs_info->sb->s_bdi->dev->kobj, "bdi");
1545         if (error)
1546                 goto failure;
1547
1548         fs_info->space_info_kobj = kobject_create_and_add("allocation",
1549                                                   fsid_kobj);
1550         if (!fs_info->space_info_kobj) {
1551                 error = -ENOMEM;
1552                 goto failure;
1553         }
1554
1555         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
1556         if (error)
1557                 goto failure;
1558
1559         return 0;
1560 failure:
1561         btrfs_sysfs_remove_mounted(fs_info);
1562         return error;
1563 }
1564
1565 static inline struct btrfs_fs_info *qgroup_kobj_to_fs_info(struct kobject *kobj)
1566 {
1567         return to_fs_info(kobj->parent->parent);
1568 }
1569
1570 #define QGROUP_ATTR(_member, _show_name)                                        \
1571 static ssize_t btrfs_qgroup_show_##_member(struct kobject *qgroup_kobj,         \
1572                                            struct kobj_attribute *a,            \
1573                                            char *buf)                           \
1574 {                                                                               \
1575         struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);    \
1576         struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,                 \
1577                         struct btrfs_qgroup, kobj);                             \
1578         return btrfs_show_u64(&qgroup->_member, &fs_info->qgroup_lock, buf);    \
1579 }                                                                               \
1580 BTRFS_ATTR(qgroup, _show_name, btrfs_qgroup_show_##_member)
1581
1582 #define QGROUP_RSV_ATTR(_name, _type)                                           \
1583 static ssize_t btrfs_qgroup_rsv_show_##_name(struct kobject *qgroup_kobj,       \
1584                                              struct kobj_attribute *a,          \
1585                                              char *buf)                         \
1586 {                                                                               \
1587         struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);    \
1588         struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,                 \
1589                         struct btrfs_qgroup, kobj);                             \
1590         return btrfs_show_u64(&qgroup->rsv.values[_type],                       \
1591                         &fs_info->qgroup_lock, buf);                            \
1592 }                                                                               \
1593 BTRFS_ATTR(qgroup, rsv_##_name, btrfs_qgroup_rsv_show_##_name)
1594
1595 QGROUP_ATTR(rfer, referenced);
1596 QGROUP_ATTR(excl, exclusive);
1597 QGROUP_ATTR(max_rfer, max_referenced);
1598 QGROUP_ATTR(max_excl, max_exclusive);
1599 QGROUP_ATTR(lim_flags, limit_flags);
1600 QGROUP_RSV_ATTR(data, BTRFS_QGROUP_RSV_DATA);
1601 QGROUP_RSV_ATTR(meta_pertrans, BTRFS_QGROUP_RSV_META_PERTRANS);
1602 QGROUP_RSV_ATTR(meta_prealloc, BTRFS_QGROUP_RSV_META_PREALLOC);
1603
1604 static struct attribute *qgroup_attrs[] = {
1605         BTRFS_ATTR_PTR(qgroup, referenced),
1606         BTRFS_ATTR_PTR(qgroup, exclusive),
1607         BTRFS_ATTR_PTR(qgroup, max_referenced),
1608         BTRFS_ATTR_PTR(qgroup, max_exclusive),
1609         BTRFS_ATTR_PTR(qgroup, limit_flags),
1610         BTRFS_ATTR_PTR(qgroup, rsv_data),
1611         BTRFS_ATTR_PTR(qgroup, rsv_meta_pertrans),
1612         BTRFS_ATTR_PTR(qgroup, rsv_meta_prealloc),
1613         NULL
1614 };
1615 ATTRIBUTE_GROUPS(qgroup);
1616
1617 static void qgroup_release(struct kobject *kobj)
1618 {
1619         struct btrfs_qgroup *qgroup = container_of(kobj, struct btrfs_qgroup, kobj);
1620
1621         memset(&qgroup->kobj, 0, sizeof(*kobj));
1622 }
1623
1624 static struct kobj_type qgroup_ktype = {
1625         .sysfs_ops = &kobj_sysfs_ops,
1626         .release = qgroup_release,
1627         .default_groups = qgroup_groups,
1628 };
1629
1630 int btrfs_sysfs_add_one_qgroup(struct btrfs_fs_info *fs_info,
1631                                 struct btrfs_qgroup *qgroup)
1632 {
1633         struct kobject *qgroups_kobj = fs_info->qgroups_kobj;
1634         int ret;
1635
1636         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
1637                 return 0;
1638         if (qgroup->kobj.state_initialized)
1639                 return 0;
1640         if (!qgroups_kobj)
1641                 return -EINVAL;
1642
1643         ret = kobject_init_and_add(&qgroup->kobj, &qgroup_ktype, qgroups_kobj,
1644                         "%hu_%llu", btrfs_qgroup_level(qgroup->qgroupid),
1645                         btrfs_qgroup_subvolid(qgroup->qgroupid));
1646         if (ret < 0)
1647                 kobject_put(&qgroup->kobj);
1648
1649         return ret;
1650 }
1651
1652 void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info)
1653 {
1654         struct btrfs_qgroup *qgroup;
1655         struct btrfs_qgroup *next;
1656
1657         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
1658                 return;
1659
1660         rbtree_postorder_for_each_entry_safe(qgroup, next,
1661                                              &fs_info->qgroup_tree, node)
1662                 btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
1663         if (fs_info->qgroups_kobj) {
1664                 kobject_del(fs_info->qgroups_kobj);
1665                 kobject_put(fs_info->qgroups_kobj);
1666                 fs_info->qgroups_kobj = NULL;
1667         }
1668 }
1669
1670 /* Called when qgroups get initialized, thus there is no need for locking */
1671 int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info)
1672 {
1673         struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1674         struct btrfs_qgroup *qgroup;
1675         struct btrfs_qgroup *next;
1676         int ret = 0;
1677
1678         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
1679                 return 0;
1680
1681         ASSERT(fsid_kobj);
1682         if (fs_info->qgroups_kobj)
1683                 return 0;
1684
1685         fs_info->qgroups_kobj = kobject_create_and_add("qgroups", fsid_kobj);
1686         if (!fs_info->qgroups_kobj) {
1687                 ret = -ENOMEM;
1688                 goto out;
1689         }
1690         rbtree_postorder_for_each_entry_safe(qgroup, next,
1691                                              &fs_info->qgroup_tree, node) {
1692                 ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
1693                 if (ret < 0)
1694                         goto out;
1695         }
1696
1697 out:
1698         if (ret < 0)
1699                 btrfs_sysfs_del_qgroups(fs_info);
1700         return ret;
1701 }
1702
1703 void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
1704                                 struct btrfs_qgroup *qgroup)
1705 {
1706         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
1707                 return;
1708
1709         if (qgroup->kobj.state_initialized) {
1710                 kobject_del(&qgroup->kobj);
1711                 kobject_put(&qgroup->kobj);
1712         }
1713 }
1714
1715 /*
1716  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
1717  * values in superblock. Call after any changes to incompat/compat_ro flags
1718  */
1719 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
1720                 u64 bit, enum btrfs_feature_set set)
1721 {
1722         struct btrfs_fs_devices *fs_devs;
1723         struct kobject *fsid_kobj;
1724         u64 __maybe_unused features;
1725         int __maybe_unused ret;
1726
1727         if (!fs_info)
1728                 return;
1729
1730         /*
1731          * See 14e46e04958df74 and e410e34fad913dd, feature bit updates are not
1732          * safe when called from some contexts (eg. balance)
1733          */
1734         features = get_features(fs_info, set);
1735         ASSERT(bit & supported_feature_masks[set]);
1736
1737         fs_devs = fs_info->fs_devices;
1738         fsid_kobj = &fs_devs->fsid_kobj;
1739
1740         if (!fsid_kobj->state_initialized)
1741                 return;
1742
1743         /*
1744          * FIXME: this is too heavy to update just one value, ideally we'd like
1745          * to use sysfs_update_group but some refactoring is needed first.
1746          */
1747         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1748         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
1749 }
1750
1751 int __init btrfs_init_sysfs(void)
1752 {
1753         int ret;
1754
1755         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
1756         if (!btrfs_kset)
1757                 return -ENOMEM;
1758
1759         init_feature_attrs();
1760         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1761         if (ret)
1762                 goto out2;
1763         ret = sysfs_merge_group(&btrfs_kset->kobj,
1764                                 &btrfs_static_feature_attr_group);
1765         if (ret)
1766                 goto out_remove_group;
1767
1768 #ifdef CONFIG_BTRFS_DEBUG
1769         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1770         if (ret)
1771                 goto out2;
1772 #endif
1773
1774         return 0;
1775
1776 out_remove_group:
1777         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1778 out2:
1779         kset_unregister(btrfs_kset);
1780
1781         return ret;
1782 }
1783
1784 void __cold btrfs_exit_sysfs(void)
1785 {
1786         sysfs_unmerge_group(&btrfs_kset->kobj,
1787                             &btrfs_static_feature_attr_group);
1788         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1789 #ifdef CONFIG_BTRFS_DEBUG
1790         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1791 #endif
1792         kset_unregister(btrfs_kset);
1793 }
1794