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 ssize_t btrfs_generation_show(struct kobject *kobj,
 858                                      struct kobj_attribute *a, char *buf)
 859 {
 860         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 861
 862         return scnprintf(buf, PAGE_SIZE, "%llu\n", fs_info->generation);
 863 }
 864 BTRFS_ATTR(, generation, btrfs_generation_show);
 865
 866 static const struct attribute *btrfs_attrs[] = {
 867         BTRFS_ATTR_PTR(, label),
 868         BTRFS_ATTR_PTR(, nodesize),
 869         BTRFS_ATTR_PTR(, sectorsize),
 870         BTRFS_ATTR_PTR(, clone_alignment),
 871         BTRFS_ATTR_PTR(, quota_override),
 872         BTRFS_ATTR_PTR(, metadata_uuid),
 873         BTRFS_ATTR_PTR(, checksum),
 874         BTRFS_ATTR_PTR(, exclusive_operation),
 875         BTRFS_ATTR_PTR(, generation),
 876         NULL,
 877 };
 878
 879 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 880 {
 881         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 882
 883         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 884         complete(&fs_devs->kobj_unregister);
 885 }
 886
 887 static struct kobj_type btrfs_ktype = {
 888         .sysfs_ops      = &kobj_sysfs_ops,
 889         .release        = btrfs_release_fsid_kobj,
 890 };
 891
 892 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 893 {
 894         if (kobj->ktype != &btrfs_ktype)
 895                 return NULL;
 896         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 897 }
 898
 899 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 900 {
 901         if (kobj->ktype != &btrfs_ktype)
 902                 return NULL;
 903         return to_fs_devs(kobj)->fs_info;
 904 }
 905
 906 #define NUM_FEATURE_BITS 64
 907 #define BTRFS_FEATURE_NAME_MAX 13
 908 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 909 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 910
 911 static const u64 supported_feature_masks[FEAT_MAX] = {
 912         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 913         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 914         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 915 };
 916
 917 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 918 {
 919         int set;
 920
 921         for (set = 0; set < FEAT_MAX; set++) {
 922                 int i;
 923                 struct attribute *attrs[2];
 924                 struct attribute_group agroup = {
 925                         .name = "features",
 926                         .attrs = attrs,
 927                 };
 928                 u64 features = get_features(fs_info, set);
 929                 features &= ~supported_feature_masks[set];
 930
 931                 if (!features)
 932                         continue;
 933
 934                 attrs[1] = NULL;
 935                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 936                         struct btrfs_feature_attr *fa;
 937
 938                         if (!(features & (1ULL << i)))
 939                                 continue;
 940
 941                         fa = &btrfs_feature_attrs[set][i];
 942                         attrs[0] = &fa->kobj_attr.attr;
 943                         if (add) {
 944                                 int ret;
 945                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 946                                                         &agroup);
 947                                 if (ret)
 948                                         return ret;
 949                         } else
 950                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 951                                                     &agroup);
 952                 }
 953
 954         }
 955         return 0;
 956 }
 957
 958 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 959 {
 960         if (fs_devs->devinfo_kobj) {
 961                 kobject_del(fs_devs->devinfo_kobj);
 962                 kobject_put(fs_devs->devinfo_kobj);
 963                 fs_devs->devinfo_kobj = NULL;
 964         }
 965
 966         if (fs_devs->devices_kobj) {
 967                 kobject_del(fs_devs->devices_kobj);
 968                 kobject_put(fs_devs->devices_kobj);
 969                 fs_devs->devices_kobj = NULL;
 970         }
 971
 972         if (fs_devs->fsid_kobj.state_initialized) {
 973                 kobject_del(&fs_devs->fsid_kobj);
 974                 kobject_put(&fs_devs->fsid_kobj);
 975                 wait_for_completion(&fs_devs->kobj_unregister);
 976         }
 977 }
 978
 979 /* when fs_devs is NULL it will remove all fsid kobject */
 980 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 981 {
 982         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 983
 984         if (fs_devs) {
 985                 __btrfs_sysfs_remove_fsid(fs_devs);
 986                 return;
 987         }
 988
 989         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 990                 __btrfs_sysfs_remove_fsid(fs_devs);
 991         }
 992 }
 993
 994 static void btrfs_sysfs_remove_fs_devices(struct btrfs_fs_devices *fs_devices)
 995 {
 996         struct btrfs_device *device;
 997         struct btrfs_fs_devices *seed;
 998
 999         list_for_each_entry(device, &fs_devices->devices, dev_list)
1000                 btrfs_sysfs_remove_device(device);
1001
1002         list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1003                 list_for_each_entry(device, &seed->devices, dev_list)
1004                         btrfs_sysfs_remove_device(device);
1005         }
1006 }
1007
1008 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
1009 {
1010         struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1011
1012         sysfs_remove_link(fsid_kobj, "bdi");
1013
1014         if (fs_info->space_info_kobj) {
1015                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
1016                 kobject_del(fs_info->space_info_kobj);
1017                 kobject_put(fs_info->space_info_kobj);
1018         }
1019 #ifdef CONFIG_BTRFS_DEBUG
1020         if (fs_info->discard_debug_kobj) {
1021                 sysfs_remove_files(fs_info->discard_debug_kobj,
1022                                    discard_debug_attrs);
1023                 kobject_del(fs_info->discard_debug_kobj);
1024                 kobject_put(fs_info->discard_debug_kobj);
1025         }
1026         if (fs_info->debug_kobj) {
1027                 sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1028                 kobject_del(fs_info->debug_kobj);
1029                 kobject_put(fs_info->debug_kobj);
1030         }
1031 #endif
1032         addrm_unknown_feature_attrs(fs_info, false);
1033         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1034         sysfs_remove_files(fsid_kobj, btrfs_attrs);
1035         btrfs_sysfs_remove_fs_devices(fs_info->fs_devices);
1036 }
1037
1038 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
1039         [FEAT_COMPAT]    = "compat",
1040         [FEAT_COMPAT_RO] = "compat_ro",
1041         [FEAT_INCOMPAT]  = "incompat",
1042 };
1043
1044 const char *btrfs_feature_set_name(enum btrfs_feature_set set)
1045 {
1046         return btrfs_feature_set_names[set];
1047 }
1048
1049 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
1050 {
1051         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
1052         int len = 0;
1053         int i;
1054         char *str;
1055
1056         str = kmalloc(bufsize, GFP_KERNEL);
1057         if (!str)
1058                 return str;
1059
1060         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1061                 const char *name;
1062
1063                 if (!(flags & (1ULL << i)))
1064                         continue;
1065
1066                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
1067                 len += scnprintf(str + len, bufsize - len, "%s%s",
1068                                 len ? "," : "", name);
1069         }
1070
1071         return str;
1072 }
1073
1074 static void init_feature_attrs(void)
1075 {
1076         struct btrfs_feature_attr *fa;
1077         int set, i;
1078
1079         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
1080                      ARRAY_SIZE(btrfs_feature_attrs));
1081         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
1082                      ARRAY_SIZE(btrfs_feature_attrs[0]));
1083
1084         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
1085         memset(btrfs_unknown_feature_names, 0,
1086                sizeof(btrfs_unknown_feature_names));
1087
1088         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
1089                 struct btrfs_feature_attr *sfa;
1090                 struct attribute *a = btrfs_supported_feature_attrs[i];
1091                 int bit;
1092                 sfa = attr_to_btrfs_feature_attr(a);
1093                 bit = ilog2(sfa->feature_bit);
1094                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
1095
1096                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
1097         }
1098
1099         for (set = 0; set < FEAT_MAX; set++) {
1100                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1101                         char *name = btrfs_unknown_feature_names[set][i];
1102                         fa = &btrfs_feature_attrs[set][i];
1103
1104                         if (fa->kobj_attr.attr.name)
1105                                 continue;
1106
1107                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
1108                                  btrfs_feature_set_names[set], i);
1109
1110                         fa->kobj_attr.attr.name = name;
1111                         fa->kobj_attr.attr.mode = S_IRUGO;
1112                         fa->feature_set = set;
1113                         fa->feature_bit = 1ULL << i;
1114                 }
1115         }
1116 }
1117
1118 /*
1119  * Create a sysfs entry for a given block group type at path
1120  * /sys/fs/btrfs/UUID/allocation/data/TYPE
1121  */
1122 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
1123 {
1124         struct btrfs_fs_info *fs_info = cache->fs_info;
1125         struct btrfs_space_info *space_info = cache->space_info;
1126         struct raid_kobject *rkobj;
1127         const int index = btrfs_bg_flags_to_raid_index(cache->flags);
1128         unsigned int nofs_flag;
1129         int ret;
1130
1131         /*
1132          * Setup a NOFS context because kobject_add(), deep in its call chain,
1133          * does GFP_KERNEL allocations, and we are often called in a context
1134          * where if reclaim is triggered we can deadlock (we are either holding
1135          * a transaction handle or some lock required for a transaction
1136          * commit).
1137          */
1138         nofs_flag = memalloc_nofs_save();
1139
1140         rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
1141         if (!rkobj) {
1142                 memalloc_nofs_restore(nofs_flag);
1143                 btrfs_warn(cache->fs_info,
1144                                 "couldn't alloc memory for raid level kobject");
1145                 return;
1146         }
1147
1148         rkobj->flags = cache->flags;
1149         kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
1150
1151         /*
1152          * We call this either on mount, or if we've created a block group for a
1153          * new index type while running (i.e. when restriping).  The running
1154          * case is tricky because we could race with other threads, so we need
1155          * to have this check to make sure we didn't already init the kobject.
1156          *
1157          * We don't have to protect on the free side because it only happens on
1158          * unmount.
1159          */
1160         spin_lock(&space_info->lock);
1161         if (space_info->block_group_kobjs[index]) {
1162                 spin_unlock(&space_info->lock);
1163                 kobject_put(&rkobj->kobj);
1164                 return;
1165         } else {
1166                 space_info->block_group_kobjs[index] = &rkobj->kobj;
1167         }
1168         spin_unlock(&space_info->lock);
1169
1170         ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
1171                           btrfs_bg_type_to_raid_name(rkobj->flags));
1172         memalloc_nofs_restore(nofs_flag);
1173         if (ret) {
1174                 spin_lock(&space_info->lock);
1175                 space_info->block_group_kobjs[index] = NULL;
1176                 spin_unlock(&space_info->lock);
1177                 kobject_put(&rkobj->kobj);
1178                 btrfs_warn(fs_info,
1179                         "failed to add kobject for block cache, ignoring");
1180                 return;
1181         }
1182 }
1183
1184 /*
1185  * Remove sysfs directories for all block group types of a given space info and
1186  * the space info as well
1187  */
1188 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
1189 {
1190         int i;
1191
1192         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1193                 struct kobject *kobj;
1194
1195                 kobj = space_info->block_group_kobjs[i];
1196                 space_info->block_group_kobjs[i] = NULL;
1197                 if (kobj) {
1198                         kobject_del(kobj);
1199                         kobject_put(kobj);
1200                 }
1201         }
1202         kobject_del(&space_info->kobj);
1203         kobject_put(&space_info->kobj);
1204 }
1205
1206 static const char *alloc_name(u64 flags)
1207 {
1208         switch (flags) {
1209         case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
1210                 return "mixed";
1211         case BTRFS_BLOCK_GROUP_METADATA:
1212                 return "metadata";
1213         case BTRFS_BLOCK_GROUP_DATA:
1214                 return "data";
1215         case BTRFS_BLOCK_GROUP_SYSTEM:
1216                 return "system";
1217         default:
1218                 WARN_ON(1);
1219                 return "invalid-combination";
1220         };
1221 }
1222
1223 /*
1224  * Create a sysfs entry for a space info type at path
1225  * /sys/fs/btrfs/UUID/allocation/TYPE
1226  */
1227 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
1228                                     struct btrfs_space_info *space_info)
1229 {
1230         int ret;
1231
1232         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
1233                                    fs_info->space_info_kobj, "%s",
1234                                    alloc_name(space_info->flags));
1235         if (ret) {
1236                 kobject_put(&space_info->kobj);
1237                 return ret;
1238         }
1239
1240         return 0;
1241 }
1242
1243 void btrfs_sysfs_remove_device(struct btrfs_device *device)
1244 {
1245         struct hd_struct *disk;
1246         struct kobject *disk_kobj;
1247         struct kobject *devices_kobj;
1248
1249         /*
1250          * Seed fs_devices devices_kobj aren't used, fetch kobject from the
1251          * fs_info::fs_devices.
1252          */
1253         devices_kobj = device->fs_info->fs_devices->devices_kobj;
1254         ASSERT(devices_kobj);
1255
1256         if (device->bdev) {
1257                 disk = device->bdev->bd_part;
1258                 disk_kobj = &part_to_dev(disk)->kobj;
1259                 sysfs_remove_link(devices_kobj, disk_kobj->name);
1260         }
1261
1262         if (device->devid_kobj.state_initialized) {
1263                 kobject_del(&device->devid_kobj);
1264                 kobject_put(&device->devid_kobj);
1265                 wait_for_completion(&device->kobj_unregister);
1266         }
1267 }
1268
1269 static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj,
1270                                                  struct kobj_attribute *a,
1271                                                  char *buf)
1272 {
1273         int val;
1274         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1275                                                    devid_kobj);
1276
1277         val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
1278
1279         return scnprintf(buf, PAGE_SIZE, "%d\n", val);
1280 }
1281 BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show);
1282
1283 static ssize_t btrfs_devinfo_missing_show(struct kobject *kobj,
1284                                         struct kobj_attribute *a, char *buf)
1285 {
1286         int val;
1287         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1288                                                    devid_kobj);
1289
1290         val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
1291
1292         return scnprintf(buf, PAGE_SIZE, "%d\n", val);
1293 }
1294 BTRFS_ATTR(devid, missing, btrfs_devinfo_missing_show);
1295
1296 static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj,
1297                                                  struct kobj_attribute *a,
1298                                                  char *buf)
1299 {
1300         int val;
1301         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1302                                                    devid_kobj);
1303
1304         val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
1305
1306         return scnprintf(buf, PAGE_SIZE, "%d\n", val);
1307 }
1308 BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show);
1309
1310 static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj,
1311                                             struct kobj_attribute *a, char *buf)
1312 {
1313         int val;
1314         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1315                                                    devid_kobj);
1316
1317         val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
1318
1319         return scnprintf(buf, PAGE_SIZE, "%d\n", val);
1320 }
1321 BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show);
1322
1323 static struct attribute *devid_attrs[] = {
1324         BTRFS_ATTR_PTR(devid, in_fs_metadata),
1325         BTRFS_ATTR_PTR(devid, missing),
1326         BTRFS_ATTR_PTR(devid, replace_target),
1327         BTRFS_ATTR_PTR(devid, writeable),
1328         NULL
1329 };
1330 ATTRIBUTE_GROUPS(devid);
1331
1332 static void btrfs_release_devid_kobj(struct kobject *kobj)
1333 {
1334         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1335                                                    devid_kobj);
1336
1337         memset(&device->devid_kobj, 0, sizeof(struct kobject));
1338         complete(&device->kobj_unregister);
1339 }
1340
1341 static struct kobj_type devid_ktype = {
1342         .sysfs_ops      = &kobj_sysfs_ops,
1343         .default_groups = devid_groups,
1344         .release        = btrfs_release_devid_kobj,
1345 };
1346
1347 int btrfs_sysfs_add_device(struct btrfs_device *device)
1348 {
1349         int ret;
1350         unsigned int nofs_flag;
1351         struct kobject *devices_kobj;
1352         struct kobject *devinfo_kobj;
1353
1354         /*
1355          * Make sure we use the fs_info::fs_devices to fetch the kobjects even
1356          * for the seed fs_devices
1357          */
1358         devices_kobj = device->fs_info->fs_devices->devices_kobj;
1359         devinfo_kobj = device->fs_info->fs_devices->devinfo_kobj;
1360         ASSERT(devices_kobj);
1361         ASSERT(devinfo_kobj);
1362
1363         nofs_flag = memalloc_nofs_save();
1364
1365         if (device->bdev) {
1366                 struct hd_struct *disk;
1367                 struct kobject *disk_kobj;
1368
1369                 disk = device->bdev->bd_part;
1370                 disk_kobj = &part_to_dev(disk)->kobj;
1371
1372                 ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
1373                 if (ret) {
1374                         btrfs_warn(device->fs_info,
1375                                 "creating sysfs device link for devid %llu failed: %d",
1376                                 device->devid, ret);
1377                         goto out;
1378                 }
1379         }
1380
1381         init_completion(&device->kobj_unregister);
1382         ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype,
1383                                    devinfo_kobj, "%llu", device->devid);
1384         if (ret) {
1385                 kobject_put(&device->devid_kobj);
1386                 btrfs_warn(device->fs_info,
1387                            "devinfo init for devid %llu failed: %d",
1388                            device->devid, ret);
1389         }
1390
1391 out:
1392         memalloc_nofs_restore(nofs_flag);
1393         return ret;
1394 }
1395
1396 static int btrfs_sysfs_add_fs_devices(struct btrfs_fs_devices *fs_devices)
1397 {
1398         int ret;
1399         struct btrfs_device *device;
1400         struct btrfs_fs_devices *seed;
1401
1402         list_for_each_entry(device, &fs_devices->devices, dev_list) {
1403                 ret = btrfs_sysfs_add_device(device);
1404                 if (ret)
1405                         goto fail;
1406         }
1407
1408         list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1409                 list_for_each_entry(device, &seed->devices, dev_list) {
1410                         ret = btrfs_sysfs_add_device(device);
1411                         if (ret)
1412                                 goto fail;
1413                 }
1414         }
1415
1416         return 0;
1417
1418 fail:
1419         btrfs_sysfs_remove_fs_devices(fs_devices);
1420         return ret;
1421 }
1422
1423 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1424 {
1425         int ret;
1426
1427         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
1428         if (ret)
1429                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
1430                         action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
1431                         &disk_to_dev(bdev->bd_disk)->kobj);
1432 }
1433
1434 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices)
1435
1436 {
1437         char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
1438
1439         /*
1440          * Sprouting changes fsid of the mounted filesystem, rename the fsid
1441          * directory
1442          */
1443         snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fs_devices->fsid);
1444         if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
1445                 btrfs_warn(fs_devices->fs_info,
1446                                 "sysfs: failed to create fsid for sprout");
1447 }
1448
1449 void btrfs_sysfs_update_devid(struct btrfs_device *device)
1450 {
1451         char tmp[24];
1452
1453         snprintf(tmp, sizeof(tmp), "%llu", device->devid);
1454
1455         if (kobject_rename(&device->devid_kobj, tmp))
1456                 btrfs_warn(device->fs_devices->fs_info,
1457                            "sysfs: failed to update devid for %llu",
1458                            device->devid);
1459 }
1460
1461 /* /sys/fs/btrfs/ entry */
1462 static struct kset *btrfs_kset;
1463
1464 /*
1465  * Creates:
1466  *              /sys/fs/btrfs/UUID
1467  *
1468  * Can be called by the device discovery thread.
1469  */
1470 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
1471 {
1472         int error;
1473
1474         init_completion(&fs_devs->kobj_unregister);
1475         fs_devs->fsid_kobj.kset = btrfs_kset;
1476         error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
1477                                      "%pU", fs_devs->fsid);
1478         if (error) {
1479                 kobject_put(&fs_devs->fsid_kobj);
1480                 return error;
1481         }
1482
1483         fs_devs->devices_kobj = kobject_create_and_add("devices",
1484                                                        &fs_devs->fsid_kobj);
1485         if (!fs_devs->devices_kobj) {
1486                 btrfs_err(fs_devs->fs_info,
1487                           "failed to init sysfs device interface");
1488                 btrfs_sysfs_remove_fsid(fs_devs);
1489                 return -ENOMEM;
1490         }
1491
1492         fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
1493                                                        &fs_devs->fsid_kobj);
1494         if (!fs_devs->devinfo_kobj) {
1495                 btrfs_err(fs_devs->fs_info,
1496                           "failed to init sysfs devinfo kobject");
1497                 btrfs_sysfs_remove_fsid(fs_devs);
1498                 return -ENOMEM;
1499         }
1500
1501         return 0;
1502 }
1503
1504 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
1505 {
1506         int error;
1507         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
1508         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
1509
1510         error = btrfs_sysfs_add_fs_devices(fs_devs);
1511         if (error)
1512                 return error;
1513
1514         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
1515         if (error) {
1516                 btrfs_sysfs_remove_fs_devices(fs_devs);
1517                 return error;
1518         }
1519
1520         error = sysfs_create_group(fsid_kobj,
1521                                    &btrfs_feature_attr_group);
1522         if (error)
1523                 goto failure;
1524
1525 #ifdef CONFIG_BTRFS_DEBUG
1526         fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
1527         if (!fs_info->debug_kobj) {
1528                 error = -ENOMEM;
1529                 goto failure;
1530         }
1531
1532         error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1533         if (error)
1534                 goto failure;
1535
1536         /* Discard directory */
1537         fs_info->discard_debug_kobj = kobject_create_and_add("discard",
1538                                                      fs_info->debug_kobj);
1539         if (!fs_info->discard_debug_kobj) {
1540                 error = -ENOMEM;
1541                 goto failure;
1542         }
1543
1544         error = sysfs_create_files(fs_info->discard_debug_kobj,
1545                                    discard_debug_attrs);
1546         if (error)
1547                 goto failure;
1548 #endif
1549
1550         error = addrm_unknown_feature_attrs(fs_info, true);
1551         if (error)
1552                 goto failure;
1553
1554         error = sysfs_create_link(fsid_kobj, &fs_info->sb->s_bdi->dev->kobj, "bdi");
1555         if (error)
1556                 goto failure;
1557
1558         fs_info->space_info_kobj = kobject_create_and_add("allocation",
1559                                                   fsid_kobj);
1560         if (!fs_info->space_info_kobj) {
1561                 error = -ENOMEM;
1562                 goto failure;
1563         }
1564
1565         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
1566         if (error)
1567                 goto failure;
1568
1569         return 0;
1570 failure:
1571         btrfs_sysfs_remove_mounted(fs_info);
1572         return error;
1573 }
1574
1575 static inline struct btrfs_fs_info *qgroup_kobj_to_fs_info(struct kobject *kobj)
1576 {
1577         return to_fs_info(kobj->parent->parent);
1578 }
1579
1580 #define QGROUP_ATTR(_member, _show_name)                                        \
1581 static ssize_t btrfs_qgroup_show_##_member(struct kobject *qgroup_kobj,         \
1582                                            struct kobj_attribute *a,            \
1583                                            char *buf)                           \
1584 {                                                                               \
1585         struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);    \
1586         struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,                 \
1587                         struct btrfs_qgroup, kobj);                             \
1588         return btrfs_show_u64(&qgroup->_member, &fs_info->qgroup_lock, buf);    \
1589 }                                                                               \
1590 BTRFS_ATTR(qgroup, _show_name, btrfs_qgroup_show_##_member)
1591
1592 #define QGROUP_RSV_ATTR(_name, _type)                                           \
1593 static ssize_t btrfs_qgroup_rsv_show_##_name(struct kobject *qgroup_kobj,       \
1594                                              struct kobj_attribute *a,          \
1595                                              char *buf)                         \
1596 {                                                                               \
1597         struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);    \
1598         struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,                 \
1599                         struct btrfs_qgroup, kobj);                             \
1600         return btrfs_show_u64(&qgroup->rsv.values[_type],                       \
1601                         &fs_info->qgroup_lock, buf);                            \
1602 }                                                                               \
1603 BTRFS_ATTR(qgroup, rsv_##_name, btrfs_qgroup_rsv_show_##_name)
1604
1605 QGROUP_ATTR(rfer, referenced);
1606 QGROUP_ATTR(excl, exclusive);
1607 QGROUP_ATTR(max_rfer, max_referenced);
1608 QGROUP_ATTR(max_excl, max_exclusive);
1609 QGROUP_ATTR(lim_flags, limit_flags);
1610 QGROUP_RSV_ATTR(data, BTRFS_QGROUP_RSV_DATA);
1611 QGROUP_RSV_ATTR(meta_pertrans, BTRFS_QGROUP_RSV_META_PERTRANS);
1612 QGROUP_RSV_ATTR(meta_prealloc, BTRFS_QGROUP_RSV_META_PREALLOC);
1613
1614 static struct attribute *qgroup_attrs[] = {
1615         BTRFS_ATTR_PTR(qgroup, referenced),
1616         BTRFS_ATTR_PTR(qgroup, exclusive),
1617         BTRFS_ATTR_PTR(qgroup, max_referenced),
1618         BTRFS_ATTR_PTR(qgroup, max_exclusive),
1619         BTRFS_ATTR_PTR(qgroup, limit_flags),
1620         BTRFS_ATTR_PTR(qgroup, rsv_data),
1621         BTRFS_ATTR_PTR(qgroup, rsv_meta_pertrans),
1622         BTRFS_ATTR_PTR(qgroup, rsv_meta_prealloc),
1623         NULL
1624 };
1625 ATTRIBUTE_GROUPS(qgroup);
1626
1627 static void qgroup_release(struct kobject *kobj)
1628 {
1629         struct btrfs_qgroup *qgroup = container_of(kobj, struct btrfs_qgroup, kobj);
1630
1631         memset(&qgroup->kobj, 0, sizeof(*kobj));
1632 }
1633
1634 static struct kobj_type qgroup_ktype = {
1635         .sysfs_ops = &kobj_sysfs_ops,
1636         .release = qgroup_release,
1637         .default_groups = qgroup_groups,
1638 };
1639
1640 int btrfs_sysfs_add_one_qgroup(struct btrfs_fs_info *fs_info,
1641                                 struct btrfs_qgroup *qgroup)
1642 {
1643         struct kobject *qgroups_kobj = fs_info->qgroups_kobj;
1644         int ret;
1645
1646         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
1647                 return 0;
1648         if (qgroup->kobj.state_initialized)
1649                 return 0;
1650         if (!qgroups_kobj)
1651                 return -EINVAL;
1652
1653         ret = kobject_init_and_add(&qgroup->kobj, &qgroup_ktype, qgroups_kobj,
1654                         "%hu_%llu", btrfs_qgroup_level(qgroup->qgroupid),
1655                         btrfs_qgroup_subvolid(qgroup->qgroupid));
1656         if (ret < 0)
1657                 kobject_put(&qgroup->kobj);
1658
1659         return ret;
1660 }
1661
1662 void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info)
1663 {
1664         struct btrfs_qgroup *qgroup;
1665         struct btrfs_qgroup *next;
1666
1667         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
1668                 return;
1669
1670         rbtree_postorder_for_each_entry_safe(qgroup, next,
1671                                              &fs_info->qgroup_tree, node)
1672                 btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
1673         if (fs_info->qgroups_kobj) {
1674                 kobject_del(fs_info->qgroups_kobj);
1675                 kobject_put(fs_info->qgroups_kobj);
1676                 fs_info->qgroups_kobj = NULL;
1677         }
1678 }
1679
1680 /* Called when qgroups get initialized, thus there is no need for locking */
1681 int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info)
1682 {
1683         struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1684         struct btrfs_qgroup *qgroup;
1685         struct btrfs_qgroup *next;
1686         int ret = 0;
1687
1688         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
1689                 return 0;
1690
1691         ASSERT(fsid_kobj);
1692         if (fs_info->qgroups_kobj)
1693                 return 0;
1694
1695         fs_info->qgroups_kobj = kobject_create_and_add("qgroups", fsid_kobj);
1696         if (!fs_info->qgroups_kobj) {
1697                 ret = -ENOMEM;
1698                 goto out;
1699         }
1700         rbtree_postorder_for_each_entry_safe(qgroup, next,
1701                                              &fs_info->qgroup_tree, node) {
1702                 ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
1703                 if (ret < 0)
1704                         goto out;
1705         }
1706
1707 out:
1708         if (ret < 0)
1709                 btrfs_sysfs_del_qgroups(fs_info);
1710         return ret;
1711 }
1712
1713 void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
1714                                 struct btrfs_qgroup *qgroup)
1715 {
1716         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
1717                 return;
1718
1719         if (qgroup->kobj.state_initialized) {
1720                 kobject_del(&qgroup->kobj);
1721                 kobject_put(&qgroup->kobj);
1722         }
1723 }
1724
1725 /*
1726  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
1727  * values in superblock. Call after any changes to incompat/compat_ro flags
1728  */
1729 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
1730                 u64 bit, enum btrfs_feature_set set)
1731 {
1732         struct btrfs_fs_devices *fs_devs;
1733         struct kobject *fsid_kobj;
1734         u64 __maybe_unused features;
1735         int __maybe_unused ret;
1736
1737         if (!fs_info)
1738                 return;
1739
1740         /*
1741          * See 14e46e04958df74 and e410e34fad913dd, feature bit updates are not
1742          * safe when called from some contexts (eg. balance)
1743          */
1744         features = get_features(fs_info, set);
1745         ASSERT(bit & supported_feature_masks[set]);
1746
1747         fs_devs = fs_info->fs_devices;
1748         fsid_kobj = &fs_devs->fsid_kobj;
1749
1750         if (!fsid_kobj->state_initialized)
1751                 return;
1752
1753         /*
1754          * FIXME: this is too heavy to update just one value, ideally we'd like
1755          * to use sysfs_update_group but some refactoring is needed first.
1756          */
1757         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1758         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
1759 }
1760
1761 int __init btrfs_init_sysfs(void)
1762 {
1763         int ret;
1764
1765         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
1766         if (!btrfs_kset)
1767                 return -ENOMEM;
1768
1769         init_feature_attrs();
1770         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1771         if (ret)
1772                 goto out2;
1773         ret = sysfs_merge_group(&btrfs_kset->kobj,
1774                                 &btrfs_static_feature_attr_group);
1775         if (ret)
1776                 goto out_remove_group;
1777
1778 #ifdef CONFIG_BTRFS_DEBUG
1779         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1780         if (ret)
1781                 goto out2;
1782 #endif
1783
1784         return 0;
1785
1786 out_remove_group:
1787         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1788 out2:
1789         kset_unregister(btrfs_kset);
1790
1791         return ret;
1792 }
1793
1794 void __cold btrfs_exit_sysfs(void)
1795 {
1796         sysfs_unmerge_group(&btrfs_kset->kobj,
1797                             &btrfs_static_feature_attr_group);
1798         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1799 #ifdef CONFIG_BTRFS_DEBUG
1800         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1801 #endif
1802         kset_unregister(btrfs_kset);
1803 }
1804