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 #include "messages.h"
  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 #include "misc.h"
  25 #include "fs.h"
  26 #include "accessors.h"
  27
  28 /*
  29  * Structure name                       Path
  30  * --------------------------------------------------------------------------
  31  * btrfs_supported_static_feature_attrs /sys/fs/btrfs/features
  32  * btrfs_supported_feature_attrs        /sys/fs/btrfs/features and
  33  *                                      /sys/fs/btrfs/<uuid>/features
  34  * btrfs_attrs                          /sys/fs/btrfs/<uuid>
  35  * devid_attrs                          /sys/fs/btrfs/<uuid>/devinfo/<devid>
  36  * allocation_attrs                     /sys/fs/btrfs/<uuid>/allocation
  37  * qgroup_attrs                         /sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>
  38  * space_info_attrs                     /sys/fs/btrfs/<uuid>/allocation/<bg-type>
  39  * raid_attrs                           /sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>
  40  * discard_attrs                        /sys/fs/btrfs/<uuid>/discard
  41  *
  42  * When built with BTRFS_CONFIG_DEBUG:
  43  *
  44  * btrfs_debug_feature_attrs            /sys/fs/btrfs/debug
  45  * btrfs_debug_mount_attrs              /sys/fs/btrfs/<uuid>/debug
  46  */
  47
  48 struct btrfs_feature_attr {
  49         struct kobj_attribute kobj_attr;
  50         enum btrfs_feature_set feature_set;
  51         u64 feature_bit;
  52 };
  53
  54 /* For raid type sysfs entries */
  55 struct raid_kobject {
  56         u64 flags;
  57         struct kobject kobj;
  58 };
  59
  60 #define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)                   \
  61 {                                                                       \
  62         .attr   = { .name = __stringify(_name), .mode = _mode },        \
  63         .show   = _show,                                                \
  64         .store  = _store,                                               \
  65 }
  66
  67 #define BTRFS_ATTR_W(_prefix, _name, _store)                            \
  68         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  69                         __INIT_KOBJ_ATTR(_name, 0200, NULL, _store)
  70
  71 #define BTRFS_ATTR_RW(_prefix, _name, _show, _store)                    \
  72         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  73                         __INIT_KOBJ_ATTR(_name, 0644, _show, _store)
  74
  75 #define BTRFS_ATTR(_prefix, _name, _show)                               \
  76         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  77                         __INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
  78
  79 #define BTRFS_ATTR_PTR(_prefix, _name)                                  \
  80         (&btrfs_attr_##_prefix##_##_name.attr)
  81
  82 #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
  83 static struct btrfs_feature_attr btrfs_attr_features_##_name = {             \
  84         .kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,                        \
  85                                       btrfs_feature_attr_show,               \
  86                                       btrfs_feature_attr_store),             \
  87         .feature_set    = _feature_set,                                      \
  88         .feature_bit    = _feature_prefix ##_## _feature_bit,                \
  89 }
  90 #define BTRFS_FEAT_ATTR_PTR(_name)                                           \
  91         (&btrfs_attr_features_##_name.kobj_attr.attr)
  92
  93 #define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
  94         BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
  95 #define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
  96         BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
  97 #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
  98         BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)
  99
 100 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
 101 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
 102 static struct kobject *get_btrfs_kobj(struct kobject *kobj);
 103
 104 static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
 105 {
 106         return container_of(a, struct btrfs_feature_attr, kobj_attr);
 107 }
 108
 109 static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
 110 {
 111         return container_of(attr, struct kobj_attribute, attr);
 112 }
 113
 114 static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
 115                 struct attribute *attr)
 116 {
 117         return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
 118 }
 119
 120 static u64 get_features(struct btrfs_fs_info *fs_info,
 121                         enum btrfs_feature_set set)
 122 {
 123         struct btrfs_super_block *disk_super = fs_info->super_copy;
 124         if (set == FEAT_COMPAT)
 125                 return btrfs_super_compat_flags(disk_super);
 126         else if (set == FEAT_COMPAT_RO)
 127                 return btrfs_super_compat_ro_flags(disk_super);
 128         else
 129                 return btrfs_super_incompat_flags(disk_super);
 130 }
 131
 132 static void set_features(struct btrfs_fs_info *fs_info,
 133                          enum btrfs_feature_set set, u64 features)
 134 {
 135         struct btrfs_super_block *disk_super = fs_info->super_copy;
 136         if (set == FEAT_COMPAT)
 137                 btrfs_set_super_compat_flags(disk_super, features);
 138         else if (set == FEAT_COMPAT_RO)
 139                 btrfs_set_super_compat_ro_flags(disk_super, features);
 140         else
 141                 btrfs_set_super_incompat_flags(disk_super, features);
 142 }
 143
 144 static int can_modify_feature(struct btrfs_feature_attr *fa)
 145 {
 146         int val = 0;
 147         u64 set, clear;
 148         switch (fa->feature_set) {
 149         case FEAT_COMPAT:
 150                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 151                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 152                 break;
 153         case FEAT_COMPAT_RO:
 154                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 155                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 156                 break;
 157         case FEAT_INCOMPAT:
 158                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 159                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 160                 break;
 161         default:
 162                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
 163                                 fa->feature_set);
 164                 return 0;
 165         }
 166
 167         if (set & fa->feature_bit)
 168                 val |= 1;
 169         if (clear & fa->feature_bit)
 170                 val |= 2;
 171
 172         return val;
 173 }
 174
 175 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
 176                                        struct kobj_attribute *a, char *buf)
 177 {
 178         int val = 0;
 179         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 180         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 181         if (fs_info) {
 182                 u64 features = get_features(fs_info, fa->feature_set);
 183                 if (features & fa->feature_bit)
 184                         val = 1;
 185         } else
 186                 val = can_modify_feature(fa);
 187
 188         return sysfs_emit(buf, "%d\n", val);
 189 }
 190
 191 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 192                                         struct kobj_attribute *a,
 193                                         const char *buf, size_t count)
 194 {
 195         struct btrfs_fs_info *fs_info;
 196         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 197         u64 features, set, clear;
 198         unsigned long val;
 199         int ret;
 200
 201         fs_info = to_fs_info(kobj);
 202         if (!fs_info)
 203                 return -EPERM;
 204
 205         if (sb_rdonly(fs_info->sb))
 206                 return -EROFS;
 207
 208         ret = kstrtoul(skip_spaces(buf), 0, &val);
 209         if (ret)
 210                 return ret;
 211
 212         if (fa->feature_set == FEAT_COMPAT) {
 213                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 214                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 215         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 216                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 217                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 218         } else {
 219                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 220                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 221         }
 222
 223         features = get_features(fs_info, fa->feature_set);
 224
 225         /* Nothing to do */
 226         if ((val && (features & fa->feature_bit)) ||
 227             (!val && !(features & fa->feature_bit)))
 228                 return count;
 229
 230         if ((val && !(set & fa->feature_bit)) ||
 231             (!val && !(clear & fa->feature_bit))) {
 232                 btrfs_info(fs_info,
 233                         "%sabling feature %s on mounted fs is not supported.",
 234                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 235                 return -EPERM;
 236         }
 237
 238         btrfs_info(fs_info, "%s %s feature flag",
 239                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 240
 241         spin_lock(&fs_info->super_lock);
 242         features = get_features(fs_info, fa->feature_set);
 243         if (val)
 244                 features |= fa->feature_bit;
 245         else
 246                 features &= ~fa->feature_bit;
 247         set_features(fs_info, fa->feature_set, features);
 248         spin_unlock(&fs_info->super_lock);
 249
 250         /*
 251          * We don't want to do full transaction commit from inside sysfs
 252          */
 253         set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
 254         wake_up_process(fs_info->transaction_kthread);
 255
 256         return count;
 257 }
 258
 259 static umode_t btrfs_feature_visible(struct kobject *kobj,
 260                                      struct attribute *attr, int unused)
 261 {
 262         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 263         umode_t mode = attr->mode;
 264
 265         if (fs_info) {
 266                 struct btrfs_feature_attr *fa;
 267                 u64 features;
 268
 269                 fa = attr_to_btrfs_feature_attr(attr);
 270                 features = get_features(fs_info, fa->feature_set);
 271
 272                 if (can_modify_feature(fa))
 273                         mode |= S_IWUSR;
 274                 else if (!(features & fa->feature_bit))
 275                         mode = 0;
 276         }
 277
 278         return mode;
 279 }
 280
 281 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 282 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 283 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 284 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
 285 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 286 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 287 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 288 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 289 BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
 290 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 291 BTRFS_FEAT_ATTR_COMPAT_RO(block_group_tree, BLOCK_GROUP_TREE);
 292 BTRFS_FEAT_ATTR_INCOMPAT(raid1c34, RAID1C34);
 293 #ifdef CONFIG_BLK_DEV_ZONED
 294 BTRFS_FEAT_ATTR_INCOMPAT(zoned, ZONED);
 295 #endif
 296 #ifdef CONFIG_BTRFS_DEBUG
 297 /* Remove once support for extent tree v2 is feature complete */
 298 BTRFS_FEAT_ATTR_INCOMPAT(extent_tree_v2, EXTENT_TREE_V2);
 299 #endif
 300 #ifdef CONFIG_FS_VERITY
 301 BTRFS_FEAT_ATTR_COMPAT_RO(verity, VERITY);
 302 #endif
 303
 304 /*
 305  * Features which depend on feature bits and may differ between each fs.
 306  *
 307  * /sys/fs/btrfs/features      - all available features implemented by this version
 308  * /sys/fs/btrfs/UUID/features - features of the fs which are enabled or
 309  *                               can be changed on a mounted filesystem.
 310  */
 311 static struct attribute *btrfs_supported_feature_attrs[] = {
 312         BTRFS_FEAT_ATTR_PTR(default_subvol),
 313         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 314         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 315         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 316         BTRFS_FEAT_ATTR_PTR(extended_iref),
 317         BTRFS_FEAT_ATTR_PTR(raid56),
 318         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 319         BTRFS_FEAT_ATTR_PTR(no_holes),
 320         BTRFS_FEAT_ATTR_PTR(metadata_uuid),
 321         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 322         BTRFS_FEAT_ATTR_PTR(raid1c34),
 323         BTRFS_FEAT_ATTR_PTR(block_group_tree),
 324 #ifdef CONFIG_BLK_DEV_ZONED
 325         BTRFS_FEAT_ATTR_PTR(zoned),
 326 #endif
 327 #ifdef CONFIG_BTRFS_DEBUG
 328         BTRFS_FEAT_ATTR_PTR(extent_tree_v2),
 329 #endif
 330 #ifdef CONFIG_FS_VERITY
 331         BTRFS_FEAT_ATTR_PTR(verity),
 332 #endif
 333         NULL
 334 };
 335
 336 static const struct attribute_group btrfs_feature_attr_group = {
 337         .name = "features",
 338         .is_visible = btrfs_feature_visible,
 339         .attrs = btrfs_supported_feature_attrs,
 340 };
 341
 342 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 343                                  struct kobj_attribute *ka, char *buf)
 344 {
 345         return sysfs_emit(buf, "0\n");
 346 }
 347 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 348
 349 static ssize_t supported_checksums_show(struct kobject *kobj,
 350                                         struct kobj_attribute *a, char *buf)
 351 {
 352         ssize_t ret = 0;
 353         int i;
 354
 355         for (i = 0; i < btrfs_get_num_csums(); i++) {
 356                 /*
 357                  * This "trick" only works as long as 'enum btrfs_csum_type' has
 358                  * no holes in it
 359                  */
 360                 ret += sysfs_emit_at(buf, ret, "%s%s", (i == 0 ? "" : " "),
 361                                      btrfs_super_csum_name(i));
 362
 363         }
 364
 365         ret += sysfs_emit_at(buf, ret, "\n");
 366         return ret;
 367 }
 368 BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);
 369
 370 static ssize_t send_stream_version_show(struct kobject *kobj,
 371                                         struct kobj_attribute *ka, char *buf)
 372 {
 373         return sysfs_emit(buf, "%d\n", BTRFS_SEND_STREAM_VERSION);
 374 }
 375 BTRFS_ATTR(static_feature, send_stream_version, send_stream_version_show);
 376
 377 static const char *rescue_opts[] = {
 378         "usebackuproot",
 379         "nologreplay",
 380         "ignorebadroots",
 381         "ignoredatacsums",
 382         "all",
 383 };
 384
 385 static ssize_t supported_rescue_options_show(struct kobject *kobj,
 386                                              struct kobj_attribute *a,
 387                                              char *buf)
 388 {
 389         ssize_t ret = 0;
 390         int i;
 391
 392         for (i = 0; i < ARRAY_SIZE(rescue_opts); i++)
 393                 ret += sysfs_emit_at(buf, ret, "%s%s", (i ? " " : ""), rescue_opts[i]);
 394         ret += sysfs_emit_at(buf, ret, "\n");
 395         return ret;
 396 }
 397 BTRFS_ATTR(static_feature, supported_rescue_options,
 398            supported_rescue_options_show);
 399
 400 static ssize_t supported_sectorsizes_show(struct kobject *kobj,
 401                                           struct kobj_attribute *a,
 402                                           char *buf)
 403 {
 404         ssize_t ret = 0;
 405
 406         /* An artificial limit to only support 4K and PAGE_SIZE */
 407         if (PAGE_SIZE > SZ_4K)
 408                 ret += sysfs_emit_at(buf, ret, "%u ", SZ_4K);
 409         ret += sysfs_emit_at(buf, ret, "%lu\n", PAGE_SIZE);
 410
 411         return ret;
 412 }
 413 BTRFS_ATTR(static_feature, supported_sectorsizes,
 414            supported_sectorsizes_show);
 415
 416 /*
 417  * Features which only depend on kernel version.
 418  *
 419  * These are listed in /sys/fs/btrfs/features along with
 420  * btrfs_supported_feature_attrs.
 421  */
 422 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 423         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 424         BTRFS_ATTR_PTR(static_feature, supported_checksums),
 425         BTRFS_ATTR_PTR(static_feature, send_stream_version),
 426         BTRFS_ATTR_PTR(static_feature, supported_rescue_options),
 427         BTRFS_ATTR_PTR(static_feature, supported_sectorsizes),
 428         NULL
 429 };
 430
 431 static const struct attribute_group btrfs_static_feature_attr_group = {
 432         .name = "features",
 433         .attrs = btrfs_supported_static_feature_attrs,
 434 };
 435
 436 /*
 437  * Discard statistics and tunables
 438  */
 439 #define discard_to_fs_info(_kobj)       to_fs_info(get_btrfs_kobj(_kobj))
 440
 441 static ssize_t btrfs_discardable_bytes_show(struct kobject *kobj,
 442                                             struct kobj_attribute *a,
 443                                             char *buf)
 444 {
 445         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 446
 447         return sysfs_emit(buf, "%lld\n",
 448                         atomic64_read(&fs_info->discard_ctl.discardable_bytes));
 449 }
 450 BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
 451
 452 static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
 453                                               struct kobj_attribute *a,
 454                                               char *buf)
 455 {
 456         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 457
 458         return sysfs_emit(buf, "%d\n",
 459                         atomic_read(&fs_info->discard_ctl.discardable_extents));
 460 }
 461 BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
 462
 463 static ssize_t btrfs_discard_bitmap_bytes_show(struct kobject *kobj,
 464                                                struct kobj_attribute *a,
 465                                                char *buf)
 466 {
 467         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 468
 469         return sysfs_emit(buf, "%llu\n",
 470                           fs_info->discard_ctl.discard_bitmap_bytes);
 471 }
 472 BTRFS_ATTR(discard, discard_bitmap_bytes, btrfs_discard_bitmap_bytes_show);
 473
 474 static ssize_t btrfs_discard_bytes_saved_show(struct kobject *kobj,
 475                                               struct kobj_attribute *a,
 476                                               char *buf)
 477 {
 478         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 479
 480         return sysfs_emit(buf, "%lld\n",
 481                 atomic64_read(&fs_info->discard_ctl.discard_bytes_saved));
 482 }
 483 BTRFS_ATTR(discard, discard_bytes_saved, btrfs_discard_bytes_saved_show);
 484
 485 static ssize_t btrfs_discard_extent_bytes_show(struct kobject *kobj,
 486                                                struct kobj_attribute *a,
 487                                                char *buf)
 488 {
 489         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 490
 491         return sysfs_emit(buf, "%llu\n",
 492                           fs_info->discard_ctl.discard_extent_bytes);
 493 }
 494 BTRFS_ATTR(discard, discard_extent_bytes, btrfs_discard_extent_bytes_show);
 495
 496 static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
 497                                              struct kobj_attribute *a,
 498                                              char *buf)
 499 {
 500         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 501
 502         return sysfs_emit(buf, "%u\n",
 503                           READ_ONCE(fs_info->discard_ctl.iops_limit));
 504 }
 505
 506 static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
 507                                               struct kobj_attribute *a,
 508                                               const char *buf, size_t len)
 509 {
 510         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 511         struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
 512         u32 iops_limit;
 513         int ret;
 514
 515         ret = kstrtou32(buf, 10, &iops_limit);
 516         if (ret)
 517                 return -EINVAL;
 518
 519         WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
 520         btrfs_discard_calc_delay(discard_ctl);
 521         btrfs_discard_schedule_work(discard_ctl, true);
 522         return len;
 523 }
 524 BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
 525               btrfs_discard_iops_limit_store);
 526
 527 static ssize_t btrfs_discard_kbps_limit_show(struct kobject *kobj,
 528                                              struct kobj_attribute *a,
 529                                              char *buf)
 530 {
 531         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 532
 533         return sysfs_emit(buf, "%u\n",
 534                           READ_ONCE(fs_info->discard_ctl.kbps_limit));
 535 }
 536
 537 static ssize_t btrfs_discard_kbps_limit_store(struct kobject *kobj,
 538                                               struct kobj_attribute *a,
 539                                               const char *buf, size_t len)
 540 {
 541         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 542         struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
 543         u32 kbps_limit;
 544         int ret;
 545
 546         ret = kstrtou32(buf, 10, &kbps_limit);
 547         if (ret)
 548                 return -EINVAL;
 549
 550         WRITE_ONCE(discard_ctl->kbps_limit, kbps_limit);
 551         btrfs_discard_schedule_work(discard_ctl, true);
 552         return len;
 553 }
 554 BTRFS_ATTR_RW(discard, kbps_limit, btrfs_discard_kbps_limit_show,
 555               btrfs_discard_kbps_limit_store);
 556
 557 static ssize_t btrfs_discard_max_discard_size_show(struct kobject *kobj,
 558                                                    struct kobj_attribute *a,
 559                                                    char *buf)
 560 {
 561         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 562
 563         return sysfs_emit(buf, "%llu\n",
 564                           READ_ONCE(fs_info->discard_ctl.max_discard_size));
 565 }
 566
 567 static ssize_t btrfs_discard_max_discard_size_store(struct kobject *kobj,
 568                                                     struct kobj_attribute *a,
 569                                                     const char *buf, size_t len)
 570 {
 571         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 572         struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
 573         u64 max_discard_size;
 574         int ret;
 575
 576         ret = kstrtou64(buf, 10, &max_discard_size);
 577         if (ret)
 578                 return -EINVAL;
 579
 580         WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);
 581
 582         return len;
 583 }
 584 BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
 585               btrfs_discard_max_discard_size_store);
 586
 587 /*
 588  * Per-filesystem stats for discard (when mounted with discard=async).
 589  *
 590  * Path: /sys/fs/btrfs/<uuid>/discard/
 591  */
 592 static const struct attribute *discard_attrs[] = {
 593         BTRFS_ATTR_PTR(discard, discardable_bytes),
 594         BTRFS_ATTR_PTR(discard, discardable_extents),
 595         BTRFS_ATTR_PTR(discard, discard_bitmap_bytes),
 596         BTRFS_ATTR_PTR(discard, discard_bytes_saved),
 597         BTRFS_ATTR_PTR(discard, discard_extent_bytes),
 598         BTRFS_ATTR_PTR(discard, iops_limit),
 599         BTRFS_ATTR_PTR(discard, kbps_limit),
 600         BTRFS_ATTR_PTR(discard, max_discard_size),
 601         NULL,
 602 };
 603
 604 #ifdef CONFIG_BTRFS_DEBUG
 605
 606 /*
 607  * Per-filesystem runtime debugging exported via sysfs.
 608  *
 609  * Path: /sys/fs/btrfs/UUID/debug/
 610  */
 611 static const struct attribute *btrfs_debug_mount_attrs[] = {
 612         NULL,
 613 };
 614
 615 /*
 616  * Runtime debugging exported via sysfs, applies to all mounted filesystems.
 617  *
 618  * Path: /sys/fs/btrfs/debug
 619  */
 620 static struct attribute *btrfs_debug_feature_attrs[] = {
 621         NULL
 622 };
 623
 624 static const struct attribute_group btrfs_debug_feature_attr_group = {
 625         .name = "debug",
 626         .attrs = btrfs_debug_feature_attrs,
 627 };
 628
 629 #endif
 630
 631 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 632 {
 633         u64 val;
 634         if (lock)
 635                 spin_lock(lock);
 636         val = *value_ptr;
 637         if (lock)
 638                 spin_unlock(lock);
 639         return sysfs_emit(buf, "%llu\n", val);
 640 }
 641
 642 static ssize_t global_rsv_size_show(struct kobject *kobj,
 643                                     struct kobj_attribute *ka, char *buf)
 644 {
 645         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 646         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 647         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 648 }
 649 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 650
 651 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 652                                         struct kobj_attribute *a, char *buf)
 653 {
 654         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 655         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 656         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 657 }
 658 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 659
 660 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 661 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 662
 663 static ssize_t raid_bytes_show(struct kobject *kobj,
 664                                struct kobj_attribute *attr, char *buf);
 665 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 666 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 667
 668 static ssize_t raid_bytes_show(struct kobject *kobj,
 669                                struct kobj_attribute *attr, char *buf)
 670
 671 {
 672         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 673         struct btrfs_block_group *block_group;
 674         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 675         u64 val = 0;
 676
 677         down_read(&sinfo->groups_sem);
 678         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 679                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 680                         val += block_group->length;
 681                 else
 682                         val += block_group->used;
 683         }
 684         up_read(&sinfo->groups_sem);
 685         return sysfs_emit(buf, "%llu\n", val);
 686 }
 687
 688 /*
 689  * Allocation information about block group profiles.
 690  *
 691  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/<bg-profile>/
 692  */
 693 static struct attribute *raid_attrs[] = {
 694         BTRFS_ATTR_PTR(raid, total_bytes),
 695         BTRFS_ATTR_PTR(raid, used_bytes),
 696         NULL
 697 };
 698 ATTRIBUTE_GROUPS(raid);
 699
 700 static void release_raid_kobj(struct kobject *kobj)
 701 {
 702         kfree(to_raid_kobj(kobj));
 703 }
 704
 705 static struct kobj_type btrfs_raid_ktype = {
 706         .sysfs_ops = &kobj_sysfs_ops,
 707         .release = release_raid_kobj,
 708         .default_groups = raid_groups,
 709 };
 710
 711 #define SPACE_INFO_ATTR(field)                                          \
 712 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 713                                              struct kobj_attribute *a,  \
 714                                              char *buf)                 \
 715 {                                                                       \
 716         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 717         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 718 }                                                                       \
 719 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 720
 721 static ssize_t btrfs_chunk_size_show(struct kobject *kobj,
 722                                      struct kobj_attribute *a, char *buf)
 723 {
 724         struct btrfs_space_info *sinfo = to_space_info(kobj);
 725
 726         return sysfs_emit(buf, "%llu\n", READ_ONCE(sinfo->chunk_size));
 727 }
 728
 729 /*
 730  * Store new chunk size in space info. Can be called on a read-only filesystem.
 731  *
 732  * If the new chunk size value is larger than 10% of free space it is reduced
 733  * to match that limit. Alignment must be to 256M and the system chunk size
 734  * cannot be set.
 735  */
 736 static ssize_t btrfs_chunk_size_store(struct kobject *kobj,
 737                                       struct kobj_attribute *a,
 738                                       const char *buf, size_t len)
 739 {
 740         struct btrfs_space_info *space_info = to_space_info(kobj);
 741         struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
 742         char *retptr;
 743         u64 val;
 744
 745         if (!capable(CAP_SYS_ADMIN))
 746                 return -EPERM;
 747
 748         if (!fs_info->fs_devices)
 749                 return -EINVAL;
 750
 751         if (btrfs_is_zoned(fs_info))
 752                 return -EINVAL;
 753
 754         /* System block type must not be changed. */
 755         if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
 756                 return -EPERM;
 757
 758         val = memparse(buf, &retptr);
 759         /* There could be trailing '\n', also catch any typos after the value */
 760         retptr = skip_spaces(retptr);
 761         if (*retptr != 0 || val == 0)
 762                 return -EINVAL;
 763
 764         val = min(val, BTRFS_MAX_DATA_CHUNK_SIZE);
 765
 766         /* Limit stripe size to 10% of available space. */
 767         val = min(mult_perc(fs_info->fs_devices->total_rw_bytes, 10), val);
 768
 769         /* Must be multiple of 256M. */
 770         val &= ~((u64)SZ_256M - 1);
 771
 772         /* Must be at least 256M. */
 773         if (val < SZ_256M)
 774                 return -EINVAL;
 775
 776         btrfs_update_space_info_chunk_size(space_info, val);
 777
 778         return len;
 779 }
 780
 781 #ifdef CONFIG_BTRFS_DEBUG
 782 /*
 783  * Request chunk allocation with current chunk size.
 784  */
 785 static ssize_t btrfs_force_chunk_alloc_store(struct kobject *kobj,
 786                                              struct kobj_attribute *a,
 787                                              const char *buf, size_t len)
 788 {
 789         struct btrfs_space_info *space_info = to_space_info(kobj);
 790         struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
 791         struct btrfs_trans_handle *trans;
 792         bool val;
 793         int ret;
 794
 795         if (!capable(CAP_SYS_ADMIN))
 796                 return -EPERM;
 797
 798         if (sb_rdonly(fs_info->sb))
 799                 return -EROFS;
 800
 801         ret = kstrtobool(buf, &val);
 802         if (ret)
 803                 return ret;
 804
 805         if (!val)
 806                 return -EINVAL;
 807
 808         /*
 809          * This is unsafe to be called from sysfs context and may cause
 810          * unexpected problems.
 811          */
 812         trans = btrfs_start_transaction(fs_info->tree_root, 0);
 813         if (IS_ERR(trans))
 814                 return PTR_ERR(trans);
 815         ret = btrfs_force_chunk_alloc(trans, space_info->flags);
 816         btrfs_end_transaction(trans);
 817
 818         if (ret == 1)
 819                 return len;
 820
 821         return -ENOSPC;
 822 }
 823 BTRFS_ATTR_W(space_info, force_chunk_alloc, btrfs_force_chunk_alloc_store);
 824
 825 #endif
 826
 827 SPACE_INFO_ATTR(flags);
 828 SPACE_INFO_ATTR(total_bytes);
 829 SPACE_INFO_ATTR(bytes_used);
 830 SPACE_INFO_ATTR(bytes_pinned);
 831 SPACE_INFO_ATTR(bytes_reserved);
 832 SPACE_INFO_ATTR(bytes_may_use);
 833 SPACE_INFO_ATTR(bytes_readonly);
 834 SPACE_INFO_ATTR(bytes_zone_unusable);
 835 SPACE_INFO_ATTR(disk_used);
 836 SPACE_INFO_ATTR(disk_total);
 837 BTRFS_ATTR_RW(space_info, chunk_size, btrfs_chunk_size_show, btrfs_chunk_size_store);
 838
 839 static ssize_t btrfs_sinfo_bg_reclaim_threshold_show(struct kobject *kobj,
 840                                                      struct kobj_attribute *a,
 841                                                      char *buf)
 842 {
 843         struct btrfs_space_info *space_info = to_space_info(kobj);
 844
 845         return sysfs_emit(buf, "%d\n", READ_ONCE(space_info->bg_reclaim_threshold));
 846 }
 847
 848 static ssize_t btrfs_sinfo_bg_reclaim_threshold_store(struct kobject *kobj,
 849                                                       struct kobj_attribute *a,
 850                                                       const char *buf, size_t len)
 851 {
 852         struct btrfs_space_info *space_info = to_space_info(kobj);
 853         int thresh;
 854         int ret;
 855
 856         ret = kstrtoint(buf, 10, &thresh);
 857         if (ret)
 858                 return ret;
 859
 860         if (thresh < 0 || thresh > 100)
 861                 return -EINVAL;
 862
 863         WRITE_ONCE(space_info->bg_reclaim_threshold, thresh);
 864
 865         return len;
 866 }
 867
 868 BTRFS_ATTR_RW(space_info, bg_reclaim_threshold,
 869               btrfs_sinfo_bg_reclaim_threshold_show,
 870               btrfs_sinfo_bg_reclaim_threshold_store);
 871
 872 /*
 873  * Allocation information about block group types.
 874  *
 875  * Path: /sys/fs/btrfs/<uuid>/allocation/<bg-type>/
 876  */
 877 static struct attribute *space_info_attrs[] = {
 878         BTRFS_ATTR_PTR(space_info, flags),
 879         BTRFS_ATTR_PTR(space_info, total_bytes),
 880         BTRFS_ATTR_PTR(space_info, bytes_used),
 881         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 882         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 883         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 884         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 885         BTRFS_ATTR_PTR(space_info, bytes_zone_unusable),
 886         BTRFS_ATTR_PTR(space_info, disk_used),
 887         BTRFS_ATTR_PTR(space_info, disk_total),
 888         BTRFS_ATTR_PTR(space_info, bg_reclaim_threshold),
 889         BTRFS_ATTR_PTR(space_info, chunk_size),
 890 #ifdef CONFIG_BTRFS_DEBUG
 891         BTRFS_ATTR_PTR(space_info, force_chunk_alloc),
 892 #endif
 893         NULL,
 894 };
 895 ATTRIBUTE_GROUPS(space_info);
 896
 897 static void space_info_release(struct kobject *kobj)
 898 {
 899         struct btrfs_space_info *sinfo = to_space_info(kobj);
 900         kfree(sinfo);
 901 }
 902
 903 static struct kobj_type space_info_ktype = {
 904         .sysfs_ops = &kobj_sysfs_ops,
 905         .release = space_info_release,
 906         .default_groups = space_info_groups,
 907 };
 908
 909 /*
 910  * Allocation information about block groups.
 911  *
 912  * Path: /sys/fs/btrfs/<uuid>/allocation/
 913  */
 914 static const struct attribute *allocation_attrs[] = {
 915         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 916         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 917         NULL,
 918 };
 919
 920 static ssize_t btrfs_label_show(struct kobject *kobj,
 921                                 struct kobj_attribute *a, char *buf)
 922 {
 923         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 924         char *label = fs_info->super_copy->label;
 925         ssize_t ret;
 926
 927         spin_lock(&fs_info->super_lock);
 928         ret = sysfs_emit(buf, label[0] ? "%s\n" : "%s", label);
 929         spin_unlock(&fs_info->super_lock);
 930
 931         return ret;
 932 }
 933
 934 static ssize_t btrfs_label_store(struct kobject *kobj,
 935                                  struct kobj_attribute *a,
 936                                  const char *buf, size_t len)
 937 {
 938         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 939         size_t p_len;
 940
 941         if (!fs_info)
 942                 return -EPERM;
 943
 944         if (sb_rdonly(fs_info->sb))
 945                 return -EROFS;
 946
 947         /*
 948          * p_len is the len until the first occurrence of either
 949          * '\n' or '\0'
 950          */
 951         p_len = strcspn(buf, "\n");
 952
 953         if (p_len >= BTRFS_LABEL_SIZE)
 954                 return -EINVAL;
 955
 956         spin_lock(&fs_info->super_lock);
 957         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 958         memcpy(fs_info->super_copy->label, buf, p_len);
 959         spin_unlock(&fs_info->super_lock);
 960
 961         /*
 962          * We don't want to do full transaction commit from inside sysfs
 963          */
 964         set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
 965         wake_up_process(fs_info->transaction_kthread);
 966
 967         return len;
 968 }
 969 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 970
 971 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 972                                 struct kobj_attribute *a, char *buf)
 973 {
 974         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 975
 976         return sysfs_emit(buf, "%u\n", fs_info->super_copy->nodesize);
 977 }
 978
 979 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 980
 981 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 982                                 struct kobj_attribute *a, char *buf)
 983 {
 984         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 985
 986         return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
 987 }
 988
 989 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 990
 991 static ssize_t btrfs_commit_stats_show(struct kobject *kobj,
 992                                        struct kobj_attribute *a, char *buf)
 993 {
 994         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 995
 996         return sysfs_emit(buf,
 997                 "commits %llu\n"
 998                 "last_commit_ms %llu\n"
 999                 "max_commit_ms %llu\n"
1000                 "total_commit_ms %llu\n",
1001                 fs_info->commit_stats.commit_count,
1002                 div_u64(fs_info->commit_stats.last_commit_dur, NSEC_PER_MSEC),
1003                 div_u64(fs_info->commit_stats.max_commit_dur, NSEC_PER_MSEC),
1004                 div_u64(fs_info->commit_stats.total_commit_dur, NSEC_PER_MSEC));
1005 }
1006
1007 static ssize_t btrfs_commit_stats_store(struct kobject *kobj,
1008                                         struct kobj_attribute *a,
1009                                         const char *buf, size_t len)
1010 {
1011         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1012         unsigned long val;
1013         int ret;
1014
1015         if (!fs_info)
1016                 return -EPERM;
1017
1018         if (!capable(CAP_SYS_RESOURCE))
1019                 return -EPERM;
1020
1021         ret = kstrtoul(buf, 10, &val);
1022         if (ret)
1023                 return ret;
1024         if (val)
1025                 return -EINVAL;
1026
1027         WRITE_ONCE(fs_info->commit_stats.max_commit_dur, 0);
1028
1029         return len;
1030 }
1031 BTRFS_ATTR_RW(, commit_stats, btrfs_commit_stats_show, btrfs_commit_stats_store);
1032
1033 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
1034                                 struct kobj_attribute *a, char *buf)
1035 {
1036         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1037
1038         return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
1039 }
1040
1041 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
1042
1043 static ssize_t quota_override_show(struct kobject *kobj,
1044                                    struct kobj_attribute *a, char *buf)
1045 {
1046         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1047         int quota_override;
1048
1049         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1050         return sysfs_emit(buf, "%d\n", quota_override);
1051 }
1052
1053 static ssize_t quota_override_store(struct kobject *kobj,
1054                                     struct kobj_attribute *a,
1055                                     const char *buf, size_t len)
1056 {
1057         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1058         unsigned long knob;
1059         int err;
1060
1061         if (!fs_info)
1062                 return -EPERM;
1063
1064         if (!capable(CAP_SYS_RESOURCE))
1065                 return -EPERM;
1066
1067         err = kstrtoul(buf, 10, &knob);
1068         if (err)
1069                 return err;
1070         if (knob > 1)
1071                 return -EINVAL;
1072
1073         if (knob)
1074                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1075         else
1076                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
1077
1078         return len;
1079 }
1080
1081 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
1082
1083 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
1084                                 struct kobj_attribute *a, char *buf)
1085 {
1086         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1087
1088         return sysfs_emit(buf, "%pU\n", fs_info->fs_devices->metadata_uuid);
1089 }
1090
1091 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
1092
1093 static ssize_t btrfs_checksum_show(struct kobject *kobj,
1094                                    struct kobj_attribute *a, char *buf)
1095 {
1096         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1097         u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
1098
1099         return sysfs_emit(buf, "%s (%s)\n",
1100                           btrfs_super_csum_name(csum_type),
1101                           crypto_shash_driver_name(fs_info->csum_shash));
1102 }
1103
1104 BTRFS_ATTR(, checksum, btrfs_checksum_show);
1105
1106 static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
1107                 struct kobj_attribute *a, char *buf)
1108 {
1109         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1110         const char *str;
1111
1112         switch (READ_ONCE(fs_info->exclusive_operation)) {
1113                 case  BTRFS_EXCLOP_NONE:
1114                         str = "none\n";
1115                         break;
1116                 case BTRFS_EXCLOP_BALANCE:
1117                         str = "balance\n";
1118                         break;
1119                 case BTRFS_EXCLOP_BALANCE_PAUSED:
1120                         str = "balance paused\n";
1121                         break;
1122                 case BTRFS_EXCLOP_DEV_ADD:
1123                         str = "device add\n";
1124                         break;
1125                 case BTRFS_EXCLOP_DEV_REMOVE:
1126                         str = "device remove\n";
1127                         break;
1128                 case BTRFS_EXCLOP_DEV_REPLACE:
1129                         str = "device replace\n";
1130                         break;
1131                 case BTRFS_EXCLOP_RESIZE:
1132                         str = "resize\n";
1133                         break;
1134                 case BTRFS_EXCLOP_SWAP_ACTIVATE:
1135                         str = "swap activate\n";
1136                         break;
1137                 default:
1138                         str = "UNKNOWN\n";
1139                         break;
1140         }
1141         return sysfs_emit(buf, "%s", str);
1142 }
1143 BTRFS_ATTR(, exclusive_operation, btrfs_exclusive_operation_show);
1144
1145 static ssize_t btrfs_generation_show(struct kobject *kobj,
1146                                      struct kobj_attribute *a, char *buf)
1147 {
1148         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1149
1150         return sysfs_emit(buf, "%llu\n", fs_info->generation);
1151 }
1152 BTRFS_ATTR(, generation, btrfs_generation_show);
1153
1154 static const char * const btrfs_read_policy_name[] = { "pid" };
1155
1156 static ssize_t btrfs_read_policy_show(struct kobject *kobj,
1157                                       struct kobj_attribute *a, char *buf)
1158 {
1159         struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1160         ssize_t ret = 0;
1161         int i;
1162
1163         for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1164                 if (fs_devices->read_policy == i)
1165                         ret += sysfs_emit_at(buf, ret, "%s[%s]",
1166                                          (ret == 0 ? "" : " "),
1167                                          btrfs_read_policy_name[i]);
1168                 else
1169                         ret += sysfs_emit_at(buf, ret, "%s%s",
1170                                          (ret == 0 ? "" : " "),
1171                                          btrfs_read_policy_name[i]);
1172         }
1173
1174         ret += sysfs_emit_at(buf, ret, "\n");
1175
1176         return ret;
1177 }
1178
1179 static ssize_t btrfs_read_policy_store(struct kobject *kobj,
1180                                        struct kobj_attribute *a,
1181                                        const char *buf, size_t len)
1182 {
1183         struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
1184         int i;
1185
1186         for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
1187                 if (sysfs_streq(buf, btrfs_read_policy_name[i])) {
1188                         if (i != fs_devices->read_policy) {
1189                                 fs_devices->read_policy = i;
1190                                 btrfs_info(fs_devices->fs_info,
1191                                            "read policy set to '%s'",
1192                                            btrfs_read_policy_name[i]);
1193                         }
1194                         return len;
1195                 }
1196         }
1197
1198         return -EINVAL;
1199 }
1200 BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store);
1201
1202 static ssize_t btrfs_bg_reclaim_threshold_show(struct kobject *kobj,
1203                                                struct kobj_attribute *a,
1204                                                char *buf)
1205 {
1206         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1207
1208         return sysfs_emit(buf, "%d\n", READ_ONCE(fs_info->bg_reclaim_threshold));
1209 }
1210
1211 static ssize_t btrfs_bg_reclaim_threshold_store(struct kobject *kobj,
1212                                                 struct kobj_attribute *a,
1213                                                 const char *buf, size_t len)
1214 {
1215         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
1216         int thresh;
1217         int ret;
1218
1219         ret = kstrtoint(buf, 10, &thresh);
1220         if (ret)
1221                 return ret;
1222
1223         if (thresh != 0 && (thresh <= 50 || thresh > 100))
1224                 return -EINVAL;
1225
1226         WRITE_ONCE(fs_info->bg_reclaim_threshold, thresh);
1227
1228         return len;
1229 }
1230 BTRFS_ATTR_RW(, bg_reclaim_threshold, btrfs_bg_reclaim_threshold_show,
1231               btrfs_bg_reclaim_threshold_store);
1232
1233 /*
1234  * Per-filesystem information and stats.
1235  *
1236  * Path: /sys/fs/btrfs/<uuid>/
1237  */
1238 static const struct attribute *btrfs_attrs[] = {
1239         BTRFS_ATTR_PTR(, label),
1240         BTRFS_ATTR_PTR(, nodesize),
1241         BTRFS_ATTR_PTR(, sectorsize),
1242         BTRFS_ATTR_PTR(, clone_alignment),
1243         BTRFS_ATTR_PTR(, quota_override),
1244         BTRFS_ATTR_PTR(, metadata_uuid),
1245         BTRFS_ATTR_PTR(, checksum),
1246         BTRFS_ATTR_PTR(, exclusive_operation),
1247         BTRFS_ATTR_PTR(, generation),
1248         BTRFS_ATTR_PTR(, read_policy),
1249         BTRFS_ATTR_PTR(, bg_reclaim_threshold),
1250         BTRFS_ATTR_PTR(, commit_stats),
1251         NULL,
1252 };
1253
1254 static void btrfs_release_fsid_kobj(struct kobject *kobj)
1255 {
1256         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
1257
1258         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
1259         complete(&fs_devs->kobj_unregister);
1260 }
1261
1262 static struct kobj_type btrfs_ktype = {
1263         .sysfs_ops      = &kobj_sysfs_ops,
1264         .release        = btrfs_release_fsid_kobj,
1265 };
1266
1267 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
1268 {
1269         if (kobj->ktype != &btrfs_ktype)
1270                 return NULL;
1271         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
1272 }
1273
1274 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
1275 {
1276         if (kobj->ktype != &btrfs_ktype)
1277                 return NULL;
1278         return to_fs_devs(kobj)->fs_info;
1279 }
1280
1281 static struct kobject *get_btrfs_kobj(struct kobject *kobj)
1282 {
1283         while (kobj) {
1284                 if (kobj->ktype == &btrfs_ktype)
1285                         return kobj;
1286                 kobj = kobj->parent;
1287         }
1288         return NULL;
1289 }
1290
1291 #define NUM_FEATURE_BITS 64
1292 #define BTRFS_FEATURE_NAME_MAX 13
1293 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
1294 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
1295
1296 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names) ==
1297               ARRAY_SIZE(btrfs_feature_attrs));
1298 static_assert(ARRAY_SIZE(btrfs_unknown_feature_names[0]) ==
1299               ARRAY_SIZE(btrfs_feature_attrs[0]));
1300
1301 static const u64 supported_feature_masks[FEAT_MAX] = {
1302         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
1303         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
1304         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
1305 };
1306
1307 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
1308 {
1309         int set;
1310
1311         for (set = 0; set < FEAT_MAX; set++) {
1312                 int i;
1313                 struct attribute *attrs[2];
1314                 struct attribute_group agroup = {
1315                         .name = "features",
1316                         .attrs = attrs,
1317                 };
1318                 u64 features = get_features(fs_info, set);
1319                 features &= ~supported_feature_masks[set];
1320
1321                 if (!features)
1322                         continue;
1323
1324                 attrs[1] = NULL;
1325                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
1326                         struct btrfs_feature_attr *fa;
1327
1328                         if (!(features & (1ULL << i)))
1329                                 continue;
1330
1331                         fa = &btrfs_feature_attrs[set][i];
1332                         attrs[0] = &fa->kobj_attr.attr;
1333                         if (add) {
1334                                 int ret;
1335                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
1336                                                         &agroup);
1337                                 if (ret)
1338                                         return ret;
1339                         } else
1340                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
1341                                                     &agroup);
1342                 }
1343
1344         }
1345         return 0;
1346 }
1347
1348 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1349 {
1350         if (fs_devs->devinfo_kobj) {
1351                 kobject_del(fs_devs->devinfo_kobj);
1352                 kobject_put(fs_devs->devinfo_kobj);
1353                 fs_devs->devinfo_kobj = NULL;
1354         }
1355
1356         if (fs_devs->devices_kobj) {
1357                 kobject_del(fs_devs->devices_kobj);
1358                 kobject_put(fs_devs->devices_kobj);
1359                 fs_devs->devices_kobj = NULL;
1360         }
1361
1362         if (fs_devs->fsid_kobj.state_initialized) {
1363                 kobject_del(&fs_devs->fsid_kobj);
1364                 kobject_put(&fs_devs->fsid_kobj);
1365                 wait_for_completion(&fs_devs->kobj_unregister);
1366         }
1367 }
1368
1369 /* when fs_devs is NULL it will remove all fsid kobject */
1370 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
1371 {
1372         struct list_head *fs_uuids = btrfs_get_fs_uuids();
1373
1374         if (fs_devs) {
1375                 __btrfs_sysfs_remove_fsid(fs_devs);
1376                 return;
1377         }
1378
1379         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
1380                 __btrfs_sysfs_remove_fsid(fs_devs);
1381         }
1382 }
1383
1384 static void btrfs_sysfs_remove_fs_devices(struct btrfs_fs_devices *fs_devices)
1385 {
1386         struct btrfs_device *device;
1387         struct btrfs_fs_devices *seed;
1388
1389         list_for_each_entry(device, &fs_devices->devices, dev_list)
1390                 btrfs_sysfs_remove_device(device);
1391
1392         list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1393                 list_for_each_entry(device, &seed->devices, dev_list)
1394                         btrfs_sysfs_remove_device(device);
1395         }
1396 }
1397
1398 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
1399 {
1400         struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
1401
1402         sysfs_remove_link(fsid_kobj, "bdi");
1403
1404         if (fs_info->space_info_kobj) {
1405                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
1406                 kobject_del(fs_info->space_info_kobj);
1407                 kobject_put(fs_info->space_info_kobj);
1408         }
1409         if (fs_info->discard_kobj) {
1410                 sysfs_remove_files(fs_info->discard_kobj, discard_attrs);
1411                 kobject_del(fs_info->discard_kobj);
1412                 kobject_put(fs_info->discard_kobj);
1413         }
1414 #ifdef CONFIG_BTRFS_DEBUG
1415         if (fs_info->debug_kobj) {
1416                 sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1417                 kobject_del(fs_info->debug_kobj);
1418                 kobject_put(fs_info->debug_kobj);
1419         }
1420 #endif
1421         addrm_unknown_feature_attrs(fs_info, false);
1422         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1423         sysfs_remove_files(fsid_kobj, btrfs_attrs);
1424         btrfs_sysfs_remove_fs_devices(fs_info->fs_devices);
1425 }
1426
1427 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
1428         [FEAT_COMPAT]    = "compat",
1429         [FEAT_COMPAT_RO] = "compat_ro",
1430         [FEAT_INCOMPAT]  = "incompat",
1431 };
1432
1433 const char *btrfs_feature_set_name(enum btrfs_feature_set set)
1434 {
1435         return btrfs_feature_set_names[set];
1436 }
1437
1438 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
1439 {
1440         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
1441         int len = 0;
1442         int i;
1443         char *str;
1444
1445         str = kmalloc(bufsize, GFP_KERNEL);
1446         if (!str)
1447                 return str;
1448
1449         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1450                 const char *name;
1451
1452                 if (!(flags & (1ULL << i)))
1453                         continue;
1454
1455                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
1456                 len += scnprintf(str + len, bufsize - len, "%s%s",
1457                                 len ? "," : "", name);
1458         }
1459
1460         return str;
1461 }
1462
1463 static void init_feature_attrs(void)
1464 {
1465         struct btrfs_feature_attr *fa;
1466         int set, i;
1467
1468         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
1469         memset(btrfs_unknown_feature_names, 0,
1470                sizeof(btrfs_unknown_feature_names));
1471
1472         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
1473                 struct btrfs_feature_attr *sfa;
1474                 struct attribute *a = btrfs_supported_feature_attrs[i];
1475                 int bit;
1476                 sfa = attr_to_btrfs_feature_attr(a);
1477                 bit = ilog2(sfa->feature_bit);
1478                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
1479
1480                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
1481         }
1482
1483         for (set = 0; set < FEAT_MAX; set++) {
1484                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
1485                         char *name = btrfs_unknown_feature_names[set][i];
1486                         fa = &btrfs_feature_attrs[set][i];
1487
1488                         if (fa->kobj_attr.attr.name)
1489                                 continue;
1490
1491                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
1492                                  btrfs_feature_set_names[set], i);
1493
1494                         fa->kobj_attr.attr.name = name;
1495                         fa->kobj_attr.attr.mode = S_IRUGO;
1496                         fa->feature_set = set;
1497                         fa->feature_bit = 1ULL << i;
1498                 }
1499         }
1500 }
1501
1502 /*
1503  * Create a sysfs entry for a given block group type at path
1504  * /sys/fs/btrfs/UUID/allocation/data/TYPE
1505  */
1506 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
1507 {
1508         struct btrfs_fs_info *fs_info = cache->fs_info;
1509         struct btrfs_space_info *space_info = cache->space_info;
1510         struct raid_kobject *rkobj;
1511         const int index = btrfs_bg_flags_to_raid_index(cache->flags);
1512         unsigned int nofs_flag;
1513         int ret;
1514
1515         /*
1516          * Setup a NOFS context because kobject_add(), deep in its call chain,
1517          * does GFP_KERNEL allocations, and we are often called in a context
1518          * where if reclaim is triggered we can deadlock (we are either holding
1519          * a transaction handle or some lock required for a transaction
1520          * commit).
1521          */
1522         nofs_flag = memalloc_nofs_save();
1523
1524         rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
1525         if (!rkobj) {
1526                 memalloc_nofs_restore(nofs_flag);
1527                 btrfs_warn(cache->fs_info,
1528                                 "couldn't alloc memory for raid level kobject");
1529                 return;
1530         }
1531
1532         rkobj->flags = cache->flags;
1533         kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
1534
1535         /*
1536          * We call this either on mount, or if we've created a block group for a
1537          * new index type while running (i.e. when restriping).  The running
1538          * case is tricky because we could race with other threads, so we need
1539          * to have this check to make sure we didn't already init the kobject.
1540          *
1541          * We don't have to protect on the free side because it only happens on
1542          * unmount.
1543          */
1544         spin_lock(&space_info->lock);
1545         if (space_info->block_group_kobjs[index]) {
1546                 spin_unlock(&space_info->lock);
1547                 kobject_put(&rkobj->kobj);
1548                 return;
1549         } else {
1550                 space_info->block_group_kobjs[index] = &rkobj->kobj;
1551         }
1552         spin_unlock(&space_info->lock);
1553
1554         ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
1555                           btrfs_bg_type_to_raid_name(rkobj->flags));
1556         memalloc_nofs_restore(nofs_flag);
1557         if (ret) {
1558                 spin_lock(&space_info->lock);
1559                 space_info->block_group_kobjs[index] = NULL;
1560                 spin_unlock(&space_info->lock);
1561                 kobject_put(&rkobj->kobj);
1562                 btrfs_warn(fs_info,
1563                         "failed to add kobject for block cache, ignoring");
1564                 return;
1565         }
1566 }
1567
1568 /*
1569  * Remove sysfs directories for all block group types of a given space info and
1570  * the space info as well
1571  */
1572 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
1573 {
1574         int i;
1575
1576         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1577                 struct kobject *kobj;
1578
1579                 kobj = space_info->block_group_kobjs[i];
1580                 space_info->block_group_kobjs[i] = NULL;
1581                 if (kobj) {
1582                         kobject_del(kobj);
1583                         kobject_put(kobj);
1584                 }
1585         }
1586         kobject_del(&space_info->kobj);
1587         kobject_put(&space_info->kobj);
1588 }
1589
1590 static const char *alloc_name(u64 flags)
1591 {
1592         switch (flags) {
1593         case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
1594                 return "mixed";
1595         case BTRFS_BLOCK_GROUP_METADATA:
1596                 return "metadata";
1597         case BTRFS_BLOCK_GROUP_DATA:
1598                 return "data";
1599         case BTRFS_BLOCK_GROUP_SYSTEM:
1600                 return "system";
1601         default:
1602                 WARN_ON(1);
1603                 return "invalid-combination";
1604         }
1605 }
1606
1607 /*
1608  * Create a sysfs entry for a space info type at path
1609  * /sys/fs/btrfs/UUID/allocation/TYPE
1610  */
1611 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
1612                                     struct btrfs_space_info *space_info)
1613 {
1614         int ret;
1615
1616         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
1617                                    fs_info->space_info_kobj, "%s",
1618                                    alloc_name(space_info->flags));
1619         if (ret) {
1620                 kobject_put(&space_info->kobj);
1621                 return ret;
1622         }
1623
1624         return 0;
1625 }
1626
1627 void btrfs_sysfs_remove_device(struct btrfs_device *device)
1628 {
1629         struct kobject *devices_kobj;
1630
1631         /*
1632          * Seed fs_devices devices_kobj aren't used, fetch kobject from the
1633          * fs_info::fs_devices.
1634          */
1635         devices_kobj = device->fs_info->fs_devices->devices_kobj;
1636         ASSERT(devices_kobj);
1637
1638         if (device->bdev)
1639                 sysfs_remove_link(devices_kobj, bdev_kobj(device->bdev)->name);
1640
1641         if (device->devid_kobj.state_initialized) {
1642                 kobject_del(&device->devid_kobj);
1643                 kobject_put(&device->devid_kobj);
1644                 wait_for_completion(&device->kobj_unregister);
1645         }
1646 }
1647
1648 static ssize_t btrfs_devinfo_in_fs_metadata_show(struct kobject *kobj,
1649                                                  struct kobj_attribute *a,
1650                                                  char *buf)
1651 {
1652         int val;
1653         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1654                                                    devid_kobj);
1655
1656         val = !!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
1657
1658         return sysfs_emit(buf, "%d\n", val);
1659 }
1660 BTRFS_ATTR(devid, in_fs_metadata, btrfs_devinfo_in_fs_metadata_show);
1661
1662 static ssize_t btrfs_devinfo_missing_show(struct kobject *kobj,
1663                                         struct kobj_attribute *a, char *buf)
1664 {
1665         int val;
1666         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1667                                                    devid_kobj);
1668
1669         val = !!test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
1670
1671         return sysfs_emit(buf, "%d\n", val);
1672 }
1673 BTRFS_ATTR(devid, missing, btrfs_devinfo_missing_show);
1674
1675 static ssize_t btrfs_devinfo_replace_target_show(struct kobject *kobj,
1676                                                  struct kobj_attribute *a,
1677                                                  char *buf)
1678 {
1679         int val;
1680         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1681                                                    devid_kobj);
1682
1683         val = !!test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
1684
1685         return sysfs_emit(buf, "%d\n", val);
1686 }
1687 BTRFS_ATTR(devid, replace_target, btrfs_devinfo_replace_target_show);
1688
1689 static ssize_t btrfs_devinfo_scrub_speed_max_show(struct kobject *kobj,
1690                                              struct kobj_attribute *a,
1691                                              char *buf)
1692 {
1693         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1694                                                    devid_kobj);
1695
1696         return sysfs_emit(buf, "%llu\n", READ_ONCE(device->scrub_speed_max));
1697 }
1698
1699 static ssize_t btrfs_devinfo_scrub_speed_max_store(struct kobject *kobj,
1700                                               struct kobj_attribute *a,
1701                                               const char *buf, size_t len)
1702 {
1703         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1704                                                    devid_kobj);
1705         char *endptr;
1706         unsigned long long limit;
1707
1708         limit = memparse(buf, &endptr);
1709         WRITE_ONCE(device->scrub_speed_max, limit);
1710         return len;
1711 }
1712 BTRFS_ATTR_RW(devid, scrub_speed_max, btrfs_devinfo_scrub_speed_max_show,
1713               btrfs_devinfo_scrub_speed_max_store);
1714
1715 static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj,
1716                                             struct kobj_attribute *a, char *buf)
1717 {
1718         int val;
1719         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1720                                                    devid_kobj);
1721
1722         val = !!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
1723
1724         return sysfs_emit(buf, "%d\n", val);
1725 }
1726 BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show);
1727
1728 static ssize_t btrfs_devinfo_fsid_show(struct kobject *kobj,
1729                                        struct kobj_attribute *a, char *buf)
1730 {
1731         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1732                                                    devid_kobj);
1733
1734         return sysfs_emit(buf, "%pU\n", device->fs_devices->fsid);
1735 }
1736 BTRFS_ATTR(devid, fsid, btrfs_devinfo_fsid_show);
1737
1738 static ssize_t btrfs_devinfo_error_stats_show(struct kobject *kobj,
1739                 struct kobj_attribute *a, char *buf)
1740 {
1741         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1742                                                    devid_kobj);
1743
1744         if (!device->dev_stats_valid)
1745                 return sysfs_emit(buf, "invalid\n");
1746
1747         /*
1748          * Print all at once so we get a snapshot of all values from the same
1749          * time. Keep them in sync and in order of definition of
1750          * btrfs_dev_stat_values.
1751          */
1752         return sysfs_emit(buf,
1753                 "write_errs %d\n"
1754                 "read_errs %d\n"
1755                 "flush_errs %d\n"
1756                 "corruption_errs %d\n"
1757                 "generation_errs %d\n",
1758                 btrfs_dev_stat_read(device, BTRFS_DEV_STAT_WRITE_ERRS),
1759                 btrfs_dev_stat_read(device, BTRFS_DEV_STAT_READ_ERRS),
1760                 btrfs_dev_stat_read(device, BTRFS_DEV_STAT_FLUSH_ERRS),
1761                 btrfs_dev_stat_read(device, BTRFS_DEV_STAT_CORRUPTION_ERRS),
1762                 btrfs_dev_stat_read(device, BTRFS_DEV_STAT_GENERATION_ERRS));
1763 }
1764 BTRFS_ATTR(devid, error_stats, btrfs_devinfo_error_stats_show);
1765
1766 /*
1767  * Information about one device.
1768  *
1769  * Path: /sys/fs/btrfs/<uuid>/devinfo/<devid>/
1770  */
1771 static struct attribute *devid_attrs[] = {
1772         BTRFS_ATTR_PTR(devid, error_stats),
1773         BTRFS_ATTR_PTR(devid, fsid),
1774         BTRFS_ATTR_PTR(devid, in_fs_metadata),
1775         BTRFS_ATTR_PTR(devid, missing),
1776         BTRFS_ATTR_PTR(devid, replace_target),
1777         BTRFS_ATTR_PTR(devid, scrub_speed_max),
1778         BTRFS_ATTR_PTR(devid, writeable),
1779         NULL
1780 };
1781 ATTRIBUTE_GROUPS(devid);
1782
1783 static void btrfs_release_devid_kobj(struct kobject *kobj)
1784 {
1785         struct btrfs_device *device = container_of(kobj, struct btrfs_device,
1786                                                    devid_kobj);
1787
1788         memset(&device->devid_kobj, 0, sizeof(struct kobject));
1789         complete(&device->kobj_unregister);
1790 }
1791
1792 static struct kobj_type devid_ktype = {
1793         .sysfs_ops      = &kobj_sysfs_ops,
1794         .default_groups = devid_groups,
1795         .release        = btrfs_release_devid_kobj,
1796 };
1797
1798 int btrfs_sysfs_add_device(struct btrfs_device *device)
1799 {
1800         int ret;
1801         unsigned int nofs_flag;
1802         struct kobject *devices_kobj;
1803         struct kobject *devinfo_kobj;
1804
1805         /*
1806          * Make sure we use the fs_info::fs_devices to fetch the kobjects even
1807          * for the seed fs_devices
1808          */
1809         devices_kobj = device->fs_info->fs_devices->devices_kobj;
1810         devinfo_kobj = device->fs_info->fs_devices->devinfo_kobj;
1811         ASSERT(devices_kobj);
1812         ASSERT(devinfo_kobj);
1813
1814         nofs_flag = memalloc_nofs_save();
1815
1816         if (device->bdev) {
1817                 struct kobject *disk_kobj = bdev_kobj(device->bdev);
1818
1819                 ret = sysfs_create_link(devices_kobj, disk_kobj, disk_kobj->name);
1820                 if (ret) {
1821                         btrfs_warn(device->fs_info,
1822                                 "creating sysfs device link for devid %llu failed: %d",
1823                                 device->devid, ret);
1824                         goto out;
1825                 }
1826         }
1827
1828         init_completion(&device->kobj_unregister);
1829         ret = kobject_init_and_add(&device->devid_kobj, &devid_ktype,
1830                                    devinfo_kobj, "%llu", device->devid);
1831         if (ret) {
1832                 kobject_put(&device->devid_kobj);
1833                 btrfs_warn(device->fs_info,
1834                            "devinfo init for devid %llu failed: %d",
1835                            device->devid, ret);
1836         }
1837
1838 out:
1839         memalloc_nofs_restore(nofs_flag);
1840         return ret;
1841 }
1842
1843 static int btrfs_sysfs_add_fs_devices(struct btrfs_fs_devices *fs_devices)
1844 {
1845         int ret;
1846         struct btrfs_device *device;
1847         struct btrfs_fs_devices *seed;
1848
1849         list_for_each_entry(device, &fs_devices->devices, dev_list) {
1850                 ret = btrfs_sysfs_add_device(device);
1851                 if (ret)
1852                         goto fail;
1853         }
1854
1855         list_for_each_entry(seed, &fs_devices->seed_list, seed_list) {
1856                 list_for_each_entry(device, &seed->devices, dev_list) {
1857                         ret = btrfs_sysfs_add_device(device);
1858                         if (ret)
1859                                 goto fail;
1860                 }
1861         }
1862
1863         return 0;
1864
1865 fail:
1866         btrfs_sysfs_remove_fs_devices(fs_devices);
1867         return ret;
1868 }
1869
1870 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1871 {
1872         int ret;
1873
1874         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
1875         if (ret)
1876                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
1877                         action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
1878                         &disk_to_dev(bdev->bd_disk)->kobj);
1879 }
1880
1881 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices)
1882
1883 {
1884         char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
1885
1886         /*
1887          * Sprouting changes fsid of the mounted filesystem, rename the fsid
1888          * directory
1889          */
1890         snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fs_devices->fsid);
1891         if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
1892                 btrfs_warn(fs_devices->fs_info,
1893                                 "sysfs: failed to create fsid for sprout");
1894 }
1895
1896 void btrfs_sysfs_update_devid(struct btrfs_device *device)
1897 {
1898         char tmp[24];
1899
1900         snprintf(tmp, sizeof(tmp), "%llu", device->devid);
1901
1902         if (kobject_rename(&device->devid_kobj, tmp))
1903                 btrfs_warn(device->fs_devices->fs_info,
1904                            "sysfs: failed to update devid for %llu",
1905                            device->devid);
1906 }
1907
1908 /* /sys/fs/btrfs/ entry */
1909 static struct kset *btrfs_kset;
1910
1911 /*
1912  * Creates:
1913  *              /sys/fs/btrfs/UUID
1914  *
1915  * Can be called by the device discovery thread.
1916  */
1917 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
1918 {
1919         int error;
1920
1921         init_completion(&fs_devs->kobj_unregister);
1922         fs_devs->fsid_kobj.kset = btrfs_kset;
1923         error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
1924                                      "%pU", fs_devs->fsid);
1925         if (error) {
1926                 kobject_put(&fs_devs->fsid_kobj);
1927                 return error;
1928         }
1929
1930         fs_devs->devices_kobj = kobject_create_and_add("devices",
1931                                                        &fs_devs->fsid_kobj);
1932         if (!fs_devs->devices_kobj) {
1933                 btrfs_err(fs_devs->fs_info,
1934                           "failed to init sysfs device interface");
1935                 btrfs_sysfs_remove_fsid(fs_devs);
1936                 return -ENOMEM;
1937         }
1938
1939         fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
1940                                                        &fs_devs->fsid_kobj);
1941         if (!fs_devs->devinfo_kobj) {
1942                 btrfs_err(fs_devs->fs_info,
1943                           "failed to init sysfs devinfo kobject");
1944                 btrfs_sysfs_remove_fsid(fs_devs);
1945                 return -ENOMEM;
1946         }
1947
1948         return 0;
1949 }
1950
1951 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
1952 {
1953         int error;
1954         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
1955         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
1956
1957         error = btrfs_sysfs_add_fs_devices(fs_devs);
1958         if (error)
1959                 return error;
1960
1961         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
1962         if (error) {
1963                 btrfs_sysfs_remove_fs_devices(fs_devs);
1964                 return error;
1965         }
1966
1967         error = sysfs_create_group(fsid_kobj,
1968                                    &btrfs_feature_attr_group);
1969         if (error)
1970                 goto failure;
1971
1972 #ifdef CONFIG_BTRFS_DEBUG
1973         fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
1974         if (!fs_info->debug_kobj) {
1975                 error = -ENOMEM;
1976                 goto failure;
1977         }
1978
1979         error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1980         if (error)
1981                 goto failure;
1982 #endif
1983
1984         /* Discard directory */
1985         fs_info->discard_kobj = kobject_create_and_add("discard", fsid_kobj);
1986         if (!fs_info->discard_kobj) {
1987                 error = -ENOMEM;
1988                 goto failure;
1989         }
1990
1991         error = sysfs_create_files(fs_info->discard_kobj, discard_attrs);
1992         if (error)
1993                 goto failure;
1994
1995         error = addrm_unknown_feature_attrs(fs_info, true);
1996         if (error)
1997                 goto failure;
1998
1999         error = sysfs_create_link(fsid_kobj, &fs_info->sb->s_bdi->dev->kobj, "bdi");
2000         if (error)
2001                 goto failure;
2002
2003         fs_info->space_info_kobj = kobject_create_and_add("allocation",
2004                                                   fsid_kobj);
2005         if (!fs_info->space_info_kobj) {
2006                 error = -ENOMEM;
2007                 goto failure;
2008         }
2009
2010         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
2011         if (error)
2012                 goto failure;
2013
2014         return 0;
2015 failure:
2016         btrfs_sysfs_remove_mounted(fs_info);
2017         return error;
2018 }
2019
2020 static ssize_t qgroup_enabled_show(struct kobject *qgroups_kobj,
2021                                    struct kobj_attribute *a,
2022                                    char *buf)
2023 {
2024         struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2025         bool enabled;
2026
2027         spin_lock(&fs_info->qgroup_lock);
2028         enabled = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON;
2029         spin_unlock(&fs_info->qgroup_lock);
2030
2031         return sysfs_emit(buf, "%d\n", enabled);
2032 }
2033 BTRFS_ATTR(qgroups, enabled, qgroup_enabled_show);
2034
2035 static ssize_t qgroup_inconsistent_show(struct kobject *qgroups_kobj,
2036                                         struct kobj_attribute *a,
2037                                         char *buf)
2038 {
2039         struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2040         bool inconsistent;
2041
2042         spin_lock(&fs_info->qgroup_lock);
2043         inconsistent = (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT);
2044         spin_unlock(&fs_info->qgroup_lock);
2045
2046         return sysfs_emit(buf, "%d\n", inconsistent);
2047 }
2048 BTRFS_ATTR(qgroups, inconsistent, qgroup_inconsistent_show);
2049
2050 static ssize_t qgroup_drop_subtree_thres_show(struct kobject *qgroups_kobj,
2051                                               struct kobj_attribute *a,
2052                                               char *buf)
2053 {
2054         struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2055         u8 result;
2056
2057         spin_lock(&fs_info->qgroup_lock);
2058         result = fs_info->qgroup_drop_subtree_thres;
2059         spin_unlock(&fs_info->qgroup_lock);
2060
2061         return sysfs_emit(buf, "%d\n", result);
2062 }
2063
2064 static ssize_t qgroup_drop_subtree_thres_store(struct kobject *qgroups_kobj,
2065                                                struct kobj_attribute *a,
2066                                                const char *buf, size_t len)
2067 {
2068         struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
2069         u8 new_thres;
2070         int ret;
2071
2072         ret = kstrtou8(buf, 10, &new_thres);
2073         if (ret)
2074                 return -EINVAL;
2075
2076         if (new_thres > BTRFS_MAX_LEVEL)
2077                 return -EINVAL;
2078
2079         spin_lock(&fs_info->qgroup_lock);
2080         fs_info->qgroup_drop_subtree_thres = new_thres;
2081         spin_unlock(&fs_info->qgroup_lock);
2082
2083         return len;
2084 }
2085 BTRFS_ATTR_RW(qgroups, drop_subtree_threshold, qgroup_drop_subtree_thres_show,
2086               qgroup_drop_subtree_thres_store);
2087
2088 /*
2089  * Qgroups global info
2090  *
2091  * Path: /sys/fs/btrfs/<uuid>/qgroups/
2092  */
2093 static struct attribute *qgroups_attrs[] = {
2094         BTRFS_ATTR_PTR(qgroups, enabled),
2095         BTRFS_ATTR_PTR(qgroups, inconsistent),
2096         BTRFS_ATTR_PTR(qgroups, drop_subtree_threshold),
2097         NULL
2098 };
2099 ATTRIBUTE_GROUPS(qgroups);
2100
2101 static void qgroups_release(struct kobject *kobj)
2102 {
2103         kfree(kobj);
2104 }
2105
2106 static struct kobj_type qgroups_ktype = {
2107         .sysfs_ops = &kobj_sysfs_ops,
2108         .default_groups = qgroups_groups,
2109         .release = qgroups_release,
2110 };
2111
2112 static inline struct btrfs_fs_info *qgroup_kobj_to_fs_info(struct kobject *kobj)
2113 {
2114         return to_fs_info(kobj->parent->parent);
2115 }
2116
2117 #define QGROUP_ATTR(_member, _show_name)                                        \
2118 static ssize_t btrfs_qgroup_show_##_member(struct kobject *qgroup_kobj,         \
2119                                            struct kobj_attribute *a,            \
2120                                            char *buf)                           \
2121 {                                                                               \
2122         struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);    \
2123         struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,                 \
2124                         struct btrfs_qgroup, kobj);                             \
2125         return btrfs_show_u64(&qgroup->_member, &fs_info->qgroup_lock, buf);    \
2126 }                                                                               \
2127 BTRFS_ATTR(qgroup, _show_name, btrfs_qgroup_show_##_member)
2128
2129 #define QGROUP_RSV_ATTR(_name, _type)                                           \
2130 static ssize_t btrfs_qgroup_rsv_show_##_name(struct kobject *qgroup_kobj,       \
2131                                              struct kobj_attribute *a,          \
2132                                              char *buf)                         \
2133 {                                                                               \
2134         struct btrfs_fs_info *fs_info = qgroup_kobj_to_fs_info(qgroup_kobj);    \
2135         struct btrfs_qgroup *qgroup = container_of(qgroup_kobj,                 \
2136                         struct btrfs_qgroup, kobj);                             \
2137         return btrfs_show_u64(&qgroup->rsv.values[_type],                       \
2138                         &fs_info->qgroup_lock, buf);                            \
2139 }                                                                               \
2140 BTRFS_ATTR(qgroup, rsv_##_name, btrfs_qgroup_rsv_show_##_name)
2141
2142 QGROUP_ATTR(rfer, referenced);
2143 QGROUP_ATTR(excl, exclusive);
2144 QGROUP_ATTR(max_rfer, max_referenced);
2145 QGROUP_ATTR(max_excl, max_exclusive);
2146 QGROUP_ATTR(lim_flags, limit_flags);
2147 QGROUP_RSV_ATTR(data, BTRFS_QGROUP_RSV_DATA);
2148 QGROUP_RSV_ATTR(meta_pertrans, BTRFS_QGROUP_RSV_META_PERTRANS);
2149 QGROUP_RSV_ATTR(meta_prealloc, BTRFS_QGROUP_RSV_META_PREALLOC);
2150
2151 /*
2152  * Qgroup information.
2153  *
2154  * Path: /sys/fs/btrfs/<uuid>/qgroups/<level>_<qgroupid>/
2155  */
2156 static struct attribute *qgroup_attrs[] = {
2157         BTRFS_ATTR_PTR(qgroup, referenced),
2158         BTRFS_ATTR_PTR(qgroup, exclusive),
2159         BTRFS_ATTR_PTR(qgroup, max_referenced),
2160         BTRFS_ATTR_PTR(qgroup, max_exclusive),
2161         BTRFS_ATTR_PTR(qgroup, limit_flags),
2162         BTRFS_ATTR_PTR(qgroup, rsv_data),
2163         BTRFS_ATTR_PTR(qgroup, rsv_meta_pertrans),
2164         BTRFS_ATTR_PTR(qgroup, rsv_meta_prealloc),
2165         NULL
2166 };
2167 ATTRIBUTE_GROUPS(qgroup);
2168
2169 static void qgroup_release(struct kobject *kobj)
2170 {
2171         struct btrfs_qgroup *qgroup = container_of(kobj, struct btrfs_qgroup, kobj);
2172
2173         memset(&qgroup->kobj, 0, sizeof(*kobj));
2174 }
2175
2176 static struct kobj_type qgroup_ktype = {
2177         .sysfs_ops = &kobj_sysfs_ops,
2178         .release = qgroup_release,
2179         .default_groups = qgroup_groups,
2180 };
2181
2182 int btrfs_sysfs_add_one_qgroup(struct btrfs_fs_info *fs_info,
2183                                 struct btrfs_qgroup *qgroup)
2184 {
2185         struct kobject *qgroups_kobj = fs_info->qgroups_kobj;
2186         int ret;
2187
2188         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2189                 return 0;
2190         if (qgroup->kobj.state_initialized)
2191                 return 0;
2192         if (!qgroups_kobj)
2193                 return -EINVAL;
2194
2195         ret = kobject_init_and_add(&qgroup->kobj, &qgroup_ktype, qgroups_kobj,
2196                         "%hu_%llu", btrfs_qgroup_level(qgroup->qgroupid),
2197                         btrfs_qgroup_subvolid(qgroup->qgroupid));
2198         if (ret < 0)
2199                 kobject_put(&qgroup->kobj);
2200
2201         return ret;
2202 }
2203
2204 void btrfs_sysfs_del_qgroups(struct btrfs_fs_info *fs_info)
2205 {
2206         struct btrfs_qgroup *qgroup;
2207         struct btrfs_qgroup *next;
2208
2209         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2210                 return;
2211
2212         rbtree_postorder_for_each_entry_safe(qgroup, next,
2213                                              &fs_info->qgroup_tree, node)
2214                 btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
2215         if (fs_info->qgroups_kobj) {
2216                 kobject_del(fs_info->qgroups_kobj);
2217                 kobject_put(fs_info->qgroups_kobj);
2218                 fs_info->qgroups_kobj = NULL;
2219         }
2220 }
2221
2222 /* Called when qgroups get initialized, thus there is no need for locking */
2223 int btrfs_sysfs_add_qgroups(struct btrfs_fs_info *fs_info)
2224 {
2225         struct kobject *fsid_kobj = &fs_info->fs_devices->fsid_kobj;
2226         struct btrfs_qgroup *qgroup;
2227         struct btrfs_qgroup *next;
2228         int ret = 0;
2229
2230         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2231                 return 0;
2232
2233         ASSERT(fsid_kobj);
2234         if (fs_info->qgroups_kobj)
2235                 return 0;
2236
2237         fs_info->qgroups_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
2238         if (!fs_info->qgroups_kobj)
2239                 return -ENOMEM;
2240
2241         ret = kobject_init_and_add(fs_info->qgroups_kobj, &qgroups_ktype,
2242                                    fsid_kobj, "qgroups");
2243         if (ret < 0)
2244                 goto out;
2245
2246         rbtree_postorder_for_each_entry_safe(qgroup, next,
2247                                              &fs_info->qgroup_tree, node) {
2248                 ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
2249                 if (ret < 0)
2250                         goto out;
2251         }
2252
2253 out:
2254         if (ret < 0)
2255                 btrfs_sysfs_del_qgroups(fs_info);
2256         return ret;
2257 }
2258
2259 void btrfs_sysfs_del_one_qgroup(struct btrfs_fs_info *fs_info,
2260                                 struct btrfs_qgroup *qgroup)
2261 {
2262         if (test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state))
2263                 return;
2264
2265         if (qgroup->kobj.state_initialized) {
2266                 kobject_del(&qgroup->kobj);
2267                 kobject_put(&qgroup->kobj);
2268         }
2269 }
2270
2271 /*
2272  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
2273  * values in superblock. Call after any changes to incompat/compat_ro flags
2274  */
2275 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
2276                 u64 bit, enum btrfs_feature_set set)
2277 {
2278         struct btrfs_fs_devices *fs_devs;
2279         struct kobject *fsid_kobj;
2280         u64 __maybe_unused features;
2281         int __maybe_unused ret;
2282
2283         if (!fs_info)
2284                 return;
2285
2286         /*
2287          * See 14e46e04958df74 and e410e34fad913dd, feature bit updates are not
2288          * safe when called from some contexts (eg. balance)
2289          */
2290         features = get_features(fs_info, set);
2291         ASSERT(bit & supported_feature_masks[set]);
2292
2293         fs_devs = fs_info->fs_devices;
2294         fsid_kobj = &fs_devs->fsid_kobj;
2295
2296         if (!fsid_kobj->state_initialized)
2297                 return;
2298
2299         /*
2300          * FIXME: this is too heavy to update just one value, ideally we'd like
2301          * to use sysfs_update_group but some refactoring is needed first.
2302          */
2303         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
2304         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
2305 }
2306
2307 int __init btrfs_init_sysfs(void)
2308 {
2309         int ret;
2310
2311         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
2312         if (!btrfs_kset)
2313                 return -ENOMEM;
2314
2315         init_feature_attrs();
2316         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2317         if (ret)
2318                 goto out2;
2319         ret = sysfs_merge_group(&btrfs_kset->kobj,
2320                                 &btrfs_static_feature_attr_group);
2321         if (ret)
2322                 goto out_remove_group;
2323
2324 #ifdef CONFIG_BTRFS_DEBUG
2325         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2326         if (ret) {
2327                 sysfs_unmerge_group(&btrfs_kset->kobj,
2328                                     &btrfs_static_feature_attr_group);
2329                 goto out_remove_group;
2330         }
2331 #endif
2332
2333         return 0;
2334
2335 out_remove_group:
2336         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2337 out2:
2338         kset_unregister(btrfs_kset);
2339
2340         return ret;
2341 }
2342
2343 void __cold btrfs_exit_sysfs(void)
2344 {
2345         sysfs_unmerge_group(&btrfs_kset->kobj,
2346                             &btrfs_static_feature_attr_group);
2347         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
2348 #ifdef CONFIG_BTRFS_DEBUG
2349         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
2350 #endif
2351         kset_unregister(btrfs_kset);
2352 }