fs/btrfs/sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/mm.h>
   8 #include <linux/slab.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/completion.h>
  11 #include <linux/bug.h>
  12 #include <crypto/hash.h>
  13
  14 #include "ctree.h"
  15 #include "discard.h"
  16 #include "disk-io.h"
  17 #include "transaction.h"
  18 #include "sysfs.h"
  19 #include "volumes.h"
  20 #include "space-info.h"
  21 #include "block-group.h"
  22
  23 struct btrfs_feature_attr {
  24         struct kobj_attribute kobj_attr;
  25         enum btrfs_feature_set feature_set;
  26         u64 feature_bit;
  27 };
  28
  29 /* For raid type sysfs entries */
  30 struct raid_kobject {
  31         u64 flags;
  32         struct kobject kobj;
  33 };
  34
  35 #define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)                   \
  36 {                                                                       \
  37         .attr   = { .name = __stringify(_name), .mode = _mode },        \
  38         .show   = _show,                                                \
  39         .store  = _store,                                               \
  40 }
  41
  42 #define BTRFS_ATTR_RW(_prefix, _name, _show, _store)                    \
  43         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  44                         __INIT_KOBJ_ATTR(_name, 0644, _show, _store)
  45
  46 #define BTRFS_ATTR(_prefix, _name, _show)                               \
  47         static struct kobj_attribute btrfs_attr_##_prefix##_##_name =   \
  48                         __INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
  49
  50 #define BTRFS_ATTR_PTR(_prefix, _name)                                  \
  51         (&btrfs_attr_##_prefix##_##_name.attr)
  52
  53 #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
  54 static struct btrfs_feature_attr btrfs_attr_features_##_name = {             \
  55         .kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,                        \
  56                                       btrfs_feature_attr_show,               \
  57                                       btrfs_feature_attr_store),             \
  58         .feature_set    = _feature_set,                                      \
  59         .feature_bit    = _feature_prefix ##_## _feature_bit,                \
  60 }
  61 #define BTRFS_FEAT_ATTR_PTR(_name)                                           \
  62         (&btrfs_attr_features_##_name.kobj_attr.attr)
  63
  64 #define BTRFS_FEAT_ATTR_COMPAT(name, feature) \
  65         BTRFS_FEAT_ATTR(name, FEAT_COMPAT, BTRFS_FEATURE_COMPAT, feature)
  66 #define BTRFS_FEAT_ATTR_COMPAT_RO(name, feature) \
  67         BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature)
  68 #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \
  69         BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature)
  70
  71 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  72 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
  73
  74 static struct btrfs_feature_attr *to_btrfs_feature_attr(struct kobj_attribute *a)
  75 {
  76         return container_of(a, struct btrfs_feature_attr, kobj_attr);
  77 }
  78
  79 static struct kobj_attribute *attr_to_btrfs_attr(struct attribute *attr)
  80 {
  81         return container_of(attr, struct kobj_attribute, attr);
  82 }
  83
  84 static struct btrfs_feature_attr *attr_to_btrfs_feature_attr(
  85                 struct attribute *attr)
  86 {
  87         return to_btrfs_feature_attr(attr_to_btrfs_attr(attr));
  88 }
  89
  90 static u64 get_features(struct btrfs_fs_info *fs_info,
  91                         enum btrfs_feature_set set)
  92 {
  93         struct btrfs_super_block *disk_super = fs_info->super_copy;
  94         if (set == FEAT_COMPAT)
  95                 return btrfs_super_compat_flags(disk_super);
  96         else if (set == FEAT_COMPAT_RO)
  97                 return btrfs_super_compat_ro_flags(disk_super);
  98         else
  99                 return btrfs_super_incompat_flags(disk_super);
 100 }
 101
 102 static void set_features(struct btrfs_fs_info *fs_info,
 103                          enum btrfs_feature_set set, u64 features)
 104 {
 105         struct btrfs_super_block *disk_super = fs_info->super_copy;
 106         if (set == FEAT_COMPAT)
 107                 btrfs_set_super_compat_flags(disk_super, features);
 108         else if (set == FEAT_COMPAT_RO)
 109                 btrfs_set_super_compat_ro_flags(disk_super, features);
 110         else
 111                 btrfs_set_super_incompat_flags(disk_super, features);
 112 }
 113
 114 static int can_modify_feature(struct btrfs_feature_attr *fa)
 115 {
 116         int val = 0;
 117         u64 set, clear;
 118         switch (fa->feature_set) {
 119         case FEAT_COMPAT:
 120                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 121                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 122                 break;
 123         case FEAT_COMPAT_RO:
 124                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 125                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 126                 break;
 127         case FEAT_INCOMPAT:
 128                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 129                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 130                 break;
 131         default:
 132                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
 133                                 fa->feature_set);
 134                 return 0;
 135         }
 136
 137         if (set & fa->feature_bit)
 138                 val |= 1;
 139         if (clear & fa->feature_bit)
 140                 val |= 2;
 141
 142         return val;
 143 }
 144
 145 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
 146                                        struct kobj_attribute *a, char *buf)
 147 {
 148         int val = 0;
 149         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 150         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 151         if (fs_info) {
 152                 u64 features = get_features(fs_info, fa->feature_set);
 153                 if (features & fa->feature_bit)
 154                         val = 1;
 155         } else
 156                 val = can_modify_feature(fa);
 157
 158         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 159 }
 160
 161 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 162                                         struct kobj_attribute *a,
 163                                         const char *buf, size_t count)
 164 {
 165         struct btrfs_fs_info *fs_info;
 166         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 167         u64 features, set, clear;
 168         unsigned long val;
 169         int ret;
 170
 171         fs_info = to_fs_info(kobj);
 172         if (!fs_info)
 173                 return -EPERM;
 174
 175         if (sb_rdonly(fs_info->sb))
 176                 return -EROFS;
 177
 178         ret = kstrtoul(skip_spaces(buf), 0, &val);
 179         if (ret)
 180                 return ret;
 181
 182         if (fa->feature_set == FEAT_COMPAT) {
 183                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 184                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 185         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 186                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 187                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 188         } else {
 189                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 190                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 191         }
 192
 193         features = get_features(fs_info, fa->feature_set);
 194
 195         /* Nothing to do */
 196         if ((val && (features & fa->feature_bit)) ||
 197             (!val && !(features & fa->feature_bit)))
 198                 return count;
 199
 200         if ((val && !(set & fa->feature_bit)) ||
 201             (!val && !(clear & fa->feature_bit))) {
 202                 btrfs_info(fs_info,
 203                         "%sabling feature %s on mounted fs is not supported.",
 204                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 205                 return -EPERM;
 206         }
 207
 208         btrfs_info(fs_info, "%s %s feature flag",
 209                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 210
 211         spin_lock(&fs_info->super_lock);
 212         features = get_features(fs_info, fa->feature_set);
 213         if (val)
 214                 features |= fa->feature_bit;
 215         else
 216                 features &= ~fa->feature_bit;
 217         set_features(fs_info, fa->feature_set, features);
 218         spin_unlock(&fs_info->super_lock);
 219
 220         /*
 221          * We don't want to do full transaction commit from inside sysfs
 222          */
 223         btrfs_set_pending(fs_info, COMMIT);
 224         wake_up_process(fs_info->transaction_kthread);
 225
 226         return count;
 227 }
 228
 229 static umode_t btrfs_feature_visible(struct kobject *kobj,
 230                                      struct attribute *attr, int unused)
 231 {
 232         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 233         umode_t mode = attr->mode;
 234
 235         if (fs_info) {
 236                 struct btrfs_feature_attr *fa;
 237                 u64 features;
 238
 239                 fa = attr_to_btrfs_feature_attr(attr);
 240                 features = get_features(fs_info, fa->feature_set);
 241
 242                 if (can_modify_feature(fa))
 243                         mode |= S_IWUSR;
 244                 else if (!(features & fa->feature_bit))
 245                         mode = 0;
 246         }
 247
 248         return mode;
 249 }
 250
 251 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 252 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 253 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 254 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 255 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
 256 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 257 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 258 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 259 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 260 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 261 BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
 262 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 263 BTRFS_FEAT_ATTR_INCOMPAT(raid1c34, RAID1C34);
 264
 265 static struct attribute *btrfs_supported_feature_attrs[] = {
 266         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 267         BTRFS_FEAT_ATTR_PTR(default_subvol),
 268         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 269         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 270         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 271         BTRFS_FEAT_ATTR_PTR(big_metadata),
 272         BTRFS_FEAT_ATTR_PTR(extended_iref),
 273         BTRFS_FEAT_ATTR_PTR(raid56),
 274         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 275         BTRFS_FEAT_ATTR_PTR(no_holes),
 276         BTRFS_FEAT_ATTR_PTR(metadata_uuid),
 277         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 278         BTRFS_FEAT_ATTR_PTR(raid1c34),
 279         NULL
 280 };
 281
 282 /*
 283  * Features which depend on feature bits and may differ between each fs.
 284  *
 285  * /sys/fs/btrfs/features lists all available features of this kernel while
 286  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 287  * can be changed online.
 288  */
 289 static const struct attribute_group btrfs_feature_attr_group = {
 290         .name = "features",
 291         .is_visible = btrfs_feature_visible,
 292         .attrs = btrfs_supported_feature_attrs,
 293 };
 294
 295 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 296                                  struct kobj_attribute *ka, char *buf)
 297 {
 298         return snprintf(buf, PAGE_SIZE, "0\n");
 299 }
 300 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 301
 302 static ssize_t supported_checksums_show(struct kobject *kobj,
 303                                         struct kobj_attribute *a, char *buf)
 304 {
 305         ssize_t ret = 0;
 306         int i;
 307
 308         for (i = 0; i < btrfs_get_num_csums(); i++) {
 309                 /*
 310                  * This "trick" only works as long as 'enum btrfs_csum_type' has
 311                  * no holes in it
 312                  */
 313                 ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
 314                                 (i == 0 ? "" : " "), btrfs_super_csum_name(i));
 315
 316         }
 317
 318         ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n");
 319         return ret;
 320 }
 321 BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);
 322
 323 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 324         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 325         BTRFS_ATTR_PTR(static_feature, supported_checksums),
 326         NULL
 327 };
 328
 329 /*
 330  * Features which only depend on kernel version.
 331  *
 332  * These are listed in /sys/fs/btrfs/features along with
 333  * btrfs_feature_attr_group
 334  */
 335 static const struct attribute_group btrfs_static_feature_attr_group = {
 336         .name = "features",
 337         .attrs = btrfs_supported_static_feature_attrs,
 338 };
 339
 340 #ifdef CONFIG_BTRFS_DEBUG
 341
 342 /*
 343  * Discard statistics and tunables
 344  */
 345 #define discard_to_fs_info(_kobj)       to_fs_info((_kobj)->parent->parent)
 346
 347 static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
 348                                               struct kobj_attribute *a,
 349                                               char *buf)
 350 {
 351         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 352
 353         return snprintf(buf, PAGE_SIZE, "%d\n",
 354                         atomic_read(&fs_info->discard_ctl.discardable_extents));
 355 }
 356 BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
 357
 358 static const struct attribute *discard_debug_attrs[] = {
 359         BTRFS_ATTR_PTR(discard, discardable_extents),
 360         NULL,
 361 };
 362
 363 /*
 364  * Runtime debugging exported via sysfs
 365  *
 366  * /sys/fs/btrfs/debug - applies to module or all filesystems
 367  * /sys/fs/btrfs/UUID  - applies only to the given filesystem
 368  */
 369 static const struct attribute *btrfs_debug_mount_attrs[] = {
 370         NULL,
 371 };
 372
 373 static struct attribute *btrfs_debug_feature_attrs[] = {
 374         NULL
 375 };
 376
 377 static const struct attribute_group btrfs_debug_feature_attr_group = {
 378         .name = "debug",
 379         .attrs = btrfs_debug_feature_attrs,
 380 };
 381
 382 #endif
 383
 384 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 385 {
 386         u64 val;
 387         if (lock)
 388                 spin_lock(lock);
 389         val = *value_ptr;
 390         if (lock)
 391                 spin_unlock(lock);
 392         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 393 }
 394
 395 static ssize_t global_rsv_size_show(struct kobject *kobj,
 396                                     struct kobj_attribute *ka, char *buf)
 397 {
 398         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 399         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 400         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 401 }
 402 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 403
 404 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 405                                         struct kobj_attribute *a, char *buf)
 406 {
 407         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 408         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 409         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 410 }
 411 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 412
 413 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 414 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 415
 416 static ssize_t raid_bytes_show(struct kobject *kobj,
 417                                struct kobj_attribute *attr, char *buf);
 418 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 419 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 420
 421 static ssize_t raid_bytes_show(struct kobject *kobj,
 422                                struct kobj_attribute *attr, char *buf)
 423
 424 {
 425         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 426         struct btrfs_block_group *block_group;
 427         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 428         u64 val = 0;
 429
 430         down_read(&sinfo->groups_sem);
 431         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 432                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 433                         val += block_group->length;
 434                 else
 435                         val += block_group->used;
 436         }
 437         up_read(&sinfo->groups_sem);
 438         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 439 }
 440
 441 static struct attribute *raid_attrs[] = {
 442         BTRFS_ATTR_PTR(raid, total_bytes),
 443         BTRFS_ATTR_PTR(raid, used_bytes),
 444         NULL
 445 };
 446 ATTRIBUTE_GROUPS(raid);
 447
 448 static void release_raid_kobj(struct kobject *kobj)
 449 {
 450         kfree(to_raid_kobj(kobj));
 451 }
 452
 453 static struct kobj_type btrfs_raid_ktype = {
 454         .sysfs_ops = &kobj_sysfs_ops,
 455         .release = release_raid_kobj,
 456         .default_groups = raid_groups,
 457 };
 458
 459 #define SPACE_INFO_ATTR(field)                                          \
 460 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 461                                              struct kobj_attribute *a,  \
 462                                              char *buf)                 \
 463 {                                                                       \
 464         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 465         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 466 }                                                                       \
 467 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 468
 469 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 470                                                        struct kobj_attribute *a,
 471                                                        char *buf)
 472 {
 473         struct btrfs_space_info *sinfo = to_space_info(kobj);
 474         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 475         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 476 }
 477
 478 SPACE_INFO_ATTR(flags);
 479 SPACE_INFO_ATTR(total_bytes);
 480 SPACE_INFO_ATTR(bytes_used);
 481 SPACE_INFO_ATTR(bytes_pinned);
 482 SPACE_INFO_ATTR(bytes_reserved);
 483 SPACE_INFO_ATTR(bytes_may_use);
 484 SPACE_INFO_ATTR(bytes_readonly);
 485 SPACE_INFO_ATTR(disk_used);
 486 SPACE_INFO_ATTR(disk_total);
 487 BTRFS_ATTR(space_info, total_bytes_pinned,
 488            btrfs_space_info_show_total_bytes_pinned);
 489
 490 static struct attribute *space_info_attrs[] = {
 491         BTRFS_ATTR_PTR(space_info, flags),
 492         BTRFS_ATTR_PTR(space_info, total_bytes),
 493         BTRFS_ATTR_PTR(space_info, bytes_used),
 494         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 495         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 496         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 497         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 498         BTRFS_ATTR_PTR(space_info, disk_used),
 499         BTRFS_ATTR_PTR(space_info, disk_total),
 500         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 501         NULL,
 502 };
 503 ATTRIBUTE_GROUPS(space_info);
 504
 505 static void space_info_release(struct kobject *kobj)
 506 {
 507         struct btrfs_space_info *sinfo = to_space_info(kobj);
 508         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 509         kfree(sinfo);
 510 }
 511
 512 static struct kobj_type space_info_ktype = {
 513         .sysfs_ops = &kobj_sysfs_ops,
 514         .release = space_info_release,
 515         .default_groups = space_info_groups,
 516 };
 517
 518 static const struct attribute *allocation_attrs[] = {
 519         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 520         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 521         NULL,
 522 };
 523
 524 static ssize_t btrfs_label_show(struct kobject *kobj,
 525                                 struct kobj_attribute *a, char *buf)
 526 {
 527         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 528         char *label = fs_info->super_copy->label;
 529         ssize_t ret;
 530
 531         spin_lock(&fs_info->super_lock);
 532         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 533         spin_unlock(&fs_info->super_lock);
 534
 535         return ret;
 536 }
 537
 538 static ssize_t btrfs_label_store(struct kobject *kobj,
 539                                  struct kobj_attribute *a,
 540                                  const char *buf, size_t len)
 541 {
 542         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 543         size_t p_len;
 544
 545         if (!fs_info)
 546                 return -EPERM;
 547
 548         if (sb_rdonly(fs_info->sb))
 549                 return -EROFS;
 550
 551         /*
 552          * p_len is the len until the first occurrence of either
 553          * '\n' or '\0'
 554          */
 555         p_len = strcspn(buf, "\n");
 556
 557         if (p_len >= BTRFS_LABEL_SIZE)
 558                 return -EINVAL;
 559
 560         spin_lock(&fs_info->super_lock);
 561         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 562         memcpy(fs_info->super_copy->label, buf, p_len);
 563         spin_unlock(&fs_info->super_lock);
 564
 565         /*
 566          * We don't want to do full transaction commit from inside sysfs
 567          */
 568         btrfs_set_pending(fs_info, COMMIT);
 569         wake_up_process(fs_info->transaction_kthread);
 570
 571         return len;
 572 }
 573 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 574
 575 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 576                                 struct kobj_attribute *a, char *buf)
 577 {
 578         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 579
 580         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 581 }
 582
 583 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 584
 585 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 586                                 struct kobj_attribute *a, char *buf)
 587 {
 588         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 589
 590         return snprintf(buf, PAGE_SIZE, "%u\n",
 591                         fs_info->super_copy->sectorsize);
 592 }
 593
 594 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 595
 596 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 597                                 struct kobj_attribute *a, char *buf)
 598 {
 599         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 600
 601         return snprintf(buf, PAGE_SIZE, "%u\n",
 602                         fs_info->super_copy->sectorsize);
 603 }
 604
 605 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 606
 607 static ssize_t quota_override_show(struct kobject *kobj,
 608                                    struct kobj_attribute *a, char *buf)
 609 {
 610         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 611         int quota_override;
 612
 613         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 614         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 615 }
 616
 617 static ssize_t quota_override_store(struct kobject *kobj,
 618                                     struct kobj_attribute *a,
 619                                     const char *buf, size_t len)
 620 {
 621         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 622         unsigned long knob;
 623         int err;
 624
 625         if (!fs_info)
 626                 return -EPERM;
 627
 628         if (!capable(CAP_SYS_RESOURCE))
 629                 return -EPERM;
 630
 631         err = kstrtoul(buf, 10, &knob);
 632         if (err)
 633                 return err;
 634         if (knob > 1)
 635                 return -EINVAL;
 636
 637         if (knob)
 638                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 639         else
 640                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 641
 642         return len;
 643 }
 644
 645 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 646
 647 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 648                                 struct kobj_attribute *a, char *buf)
 649 {
 650         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 651
 652         return snprintf(buf, PAGE_SIZE, "%pU\n",
 653                         fs_info->fs_devices->metadata_uuid);
 654 }
 655
 656 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 657
 658 static ssize_t btrfs_checksum_show(struct kobject *kobj,
 659                                    struct kobj_attribute *a, char *buf)
 660 {
 661         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 662         u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
 663
 664         return snprintf(buf, PAGE_SIZE, "%s (%s)\n",
 665                         btrfs_super_csum_name(csum_type),
 666                         crypto_shash_driver_name(fs_info->csum_shash));
 667 }
 668
 669 BTRFS_ATTR(, checksum, btrfs_checksum_show);
 670
 671 static const struct attribute *btrfs_attrs[] = {
 672         BTRFS_ATTR_PTR(, label),
 673         BTRFS_ATTR_PTR(, nodesize),
 674         BTRFS_ATTR_PTR(, sectorsize),
 675         BTRFS_ATTR_PTR(, clone_alignment),
 676         BTRFS_ATTR_PTR(, quota_override),
 677         BTRFS_ATTR_PTR(, metadata_uuid),
 678         BTRFS_ATTR_PTR(, checksum),
 679         NULL,
 680 };
 681
 682 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 683 {
 684         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 685
 686         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 687         complete(&fs_devs->kobj_unregister);
 688 }
 689
 690 static struct kobj_type btrfs_ktype = {
 691         .sysfs_ops      = &kobj_sysfs_ops,
 692         .release        = btrfs_release_fsid_kobj,
 693 };
 694
 695 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 696 {
 697         if (kobj->ktype != &btrfs_ktype)
 698                 return NULL;
 699         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 700 }
 701
 702 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 703 {
 704         if (kobj->ktype != &btrfs_ktype)
 705                 return NULL;
 706         return to_fs_devs(kobj)->fs_info;
 707 }
 708
 709 #define NUM_FEATURE_BITS 64
 710 #define BTRFS_FEATURE_NAME_MAX 13
 711 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 712 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 713
 714 static const u64 supported_feature_masks[FEAT_MAX] = {
 715         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 716         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 717         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 718 };
 719
 720 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 721 {
 722         int set;
 723
 724         for (set = 0; set < FEAT_MAX; set++) {
 725                 int i;
 726                 struct attribute *attrs[2];
 727                 struct attribute_group agroup = {
 728                         .name = "features",
 729                         .attrs = attrs,
 730                 };
 731                 u64 features = get_features(fs_info, set);
 732                 features &= ~supported_feature_masks[set];
 733
 734                 if (!features)
 735                         continue;
 736
 737                 attrs[1] = NULL;
 738                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 739                         struct btrfs_feature_attr *fa;
 740
 741                         if (!(features & (1ULL << i)))
 742                                 continue;
 743
 744                         fa = &btrfs_feature_attrs[set][i];
 745                         attrs[0] = &fa->kobj_attr.attr;
 746                         if (add) {
 747                                 int ret;
 748                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 749                                                         &agroup);
 750                                 if (ret)
 751                                         return ret;
 752                         } else
 753                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 754                                                     &agroup);
 755                 }
 756
 757         }
 758         return 0;
 759 }
 760
 761 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 762 {
 763         if (fs_devs->devices_kobj) {
 764                 kobject_del(fs_devs->devices_kobj);
 765                 kobject_put(fs_devs->devices_kobj);
 766                 fs_devs->devices_kobj = NULL;
 767         }
 768
 769         if (fs_devs->fsid_kobj.state_initialized) {
 770                 kobject_del(&fs_devs->fsid_kobj);
 771                 kobject_put(&fs_devs->fsid_kobj);
 772                 wait_for_completion(&fs_devs->kobj_unregister);
 773         }
 774 }
 775
 776 /* when fs_devs is NULL it will remove all fsid kobject */
 777 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 778 {
 779         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 780
 781         if (fs_devs) {
 782                 __btrfs_sysfs_remove_fsid(fs_devs);
 783                 return;
 784         }
 785
 786         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 787                 __btrfs_sysfs_remove_fsid(fs_devs);
 788         }
 789 }
 790
 791 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 792 {
 793         btrfs_reset_fs_info_ptr(fs_info);
 794
 795         if (fs_info->space_info_kobj) {
 796                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 797                 kobject_del(fs_info->space_info_kobj);
 798                 kobject_put(fs_info->space_info_kobj);
 799         }
 800 #ifdef CONFIG_BTRFS_DEBUG
 801         if (fs_info->discard_debug_kobj) {
 802                 sysfs_remove_files(fs_info->discard_debug_kobj,
 803                                    discard_debug_attrs);
 804                 kobject_del(fs_info->discard_debug_kobj);
 805                 kobject_put(fs_info->discard_debug_kobj);
 806         }
 807         if (fs_info->debug_kobj) {
 808                 sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
 809                 kobject_del(fs_info->debug_kobj);
 810                 kobject_put(fs_info->debug_kobj);
 811         }
 812 #endif
 813         addrm_unknown_feature_attrs(fs_info, false);
 814         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 815         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 816         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 817 }
 818
 819 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
 820         [FEAT_COMPAT]    = "compat",
 821         [FEAT_COMPAT_RO] = "compat_ro",
 822         [FEAT_INCOMPAT]  = "incompat",
 823 };
 824
 825 const char * const btrfs_feature_set_name(enum btrfs_feature_set set)
 826 {
 827         return btrfs_feature_set_names[set];
 828 }
 829
 830 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 831 {
 832         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 833         int len = 0;
 834         int i;
 835         char *str;
 836
 837         str = kmalloc(bufsize, GFP_KERNEL);
 838         if (!str)
 839                 return str;
 840
 841         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 842                 const char *name;
 843
 844                 if (!(flags & (1ULL << i)))
 845                         continue;
 846
 847                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 848                 len += snprintf(str + len, bufsize - len, "%s%s",
 849                                 len ? "," : "", name);
 850         }
 851
 852         return str;
 853 }
 854
 855 static void init_feature_attrs(void)
 856 {
 857         struct btrfs_feature_attr *fa;
 858         int set, i;
 859
 860         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 861                      ARRAY_SIZE(btrfs_feature_attrs));
 862         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 863                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 864
 865         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 866         memset(btrfs_unknown_feature_names, 0,
 867                sizeof(btrfs_unknown_feature_names));
 868
 869         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 870                 struct btrfs_feature_attr *sfa;
 871                 struct attribute *a = btrfs_supported_feature_attrs[i];
 872                 int bit;
 873                 sfa = attr_to_btrfs_feature_attr(a);
 874                 bit = ilog2(sfa->feature_bit);
 875                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 876
 877                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 878         }
 879
 880         for (set = 0; set < FEAT_MAX; set++) {
 881                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 882                         char *name = btrfs_unknown_feature_names[set][i];
 883                         fa = &btrfs_feature_attrs[set][i];
 884
 885                         if (fa->kobj_attr.attr.name)
 886                                 continue;
 887
 888                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 889                                  btrfs_feature_set_names[set], i);
 890
 891                         fa->kobj_attr.attr.name = name;
 892                         fa->kobj_attr.attr.mode = S_IRUGO;
 893                         fa->feature_set = set;
 894                         fa->feature_bit = 1ULL << i;
 895                 }
 896         }
 897 }
 898
 899 /*
 900  * Create a sysfs entry for a given block group type at path
 901  * /sys/fs/btrfs/UUID/allocation/data/TYPE
 902  */
 903 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
 904 {
 905         struct btrfs_fs_info *fs_info = cache->fs_info;
 906         struct btrfs_space_info *space_info = cache->space_info;
 907         struct raid_kobject *rkobj;
 908         const int index = btrfs_bg_flags_to_raid_index(cache->flags);
 909         unsigned int nofs_flag;
 910         int ret;
 911
 912         /*
 913          * Setup a NOFS context because kobject_add(), deep in its call chain,
 914          * does GFP_KERNEL allocations, and we are often called in a context
 915          * where if reclaim is triggered we can deadlock (we are either holding
 916          * a transaction handle or some lock required for a transaction
 917          * commit).
 918          */
 919         nofs_flag = memalloc_nofs_save();
 920
 921         rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
 922         if (!rkobj) {
 923                 memalloc_nofs_restore(nofs_flag);
 924                 btrfs_warn(cache->fs_info,
 925                                 "couldn't alloc memory for raid level kobject");
 926                 return;
 927         }
 928
 929         rkobj->flags = cache->flags;
 930         kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
 931         ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
 932                           btrfs_bg_type_to_raid_name(rkobj->flags));
 933         memalloc_nofs_restore(nofs_flag);
 934         if (ret) {
 935                 kobject_put(&rkobj->kobj);
 936                 btrfs_warn(fs_info,
 937                         "failed to add kobject for block cache, ignoring");
 938                 return;
 939         }
 940
 941         space_info->block_group_kobjs[index] = &rkobj->kobj;
 942 }
 943
 944 /*
 945  * Remove sysfs directories for all block group types of a given space info and
 946  * the space info as well
 947  */
 948 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
 949 {
 950         int i;
 951
 952         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
 953                 struct kobject *kobj;
 954
 955                 kobj = space_info->block_group_kobjs[i];
 956                 space_info->block_group_kobjs[i] = NULL;
 957                 if (kobj) {
 958                         kobject_del(kobj);
 959                         kobject_put(kobj);
 960                 }
 961         }
 962         kobject_del(&space_info->kobj);
 963         kobject_put(&space_info->kobj);
 964 }
 965
 966 static const char *alloc_name(u64 flags)
 967 {
 968         switch (flags) {
 969         case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
 970                 return "mixed";
 971         case BTRFS_BLOCK_GROUP_METADATA:
 972                 return "metadata";
 973         case BTRFS_BLOCK_GROUP_DATA:
 974                 return "data";
 975         case BTRFS_BLOCK_GROUP_SYSTEM:
 976                 return "system";
 977         default:
 978                 WARN_ON(1);
 979                 return "invalid-combination";
 980         };
 981 }
 982
 983 /*
 984  * Create a sysfs entry for a space info type at path
 985  * /sys/fs/btrfs/UUID/allocation/TYPE
 986  */
 987 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
 988                                     struct btrfs_space_info *space_info)
 989 {
 990         int ret;
 991
 992         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
 993                                    fs_info->space_info_kobj, "%s",
 994                                    alloc_name(space_info->flags));
 995         if (ret) {
 996                 kobject_put(&space_info->kobj);
 997                 return ret;
 998         }
 999
1000         return 0;
1001 }
1002
1003 /* when one_device is NULL, it removes all device links */
1004
1005 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
1006                 struct btrfs_device *one_device)
1007 {
1008         struct hd_struct *disk;
1009         struct kobject *disk_kobj;
1010
1011         if (!fs_devices->devices_kobj)
1012                 return -EINVAL;
1013
1014         if (one_device && one_device->bdev) {
1015                 disk = one_device->bdev->bd_part;
1016                 disk_kobj = &part_to_dev(disk)->kobj;
1017
1018                 sysfs_remove_link(fs_devices->devices_kobj, disk_kobj->name);
1019         }
1020
1021         if (one_device)
1022                 return 0;
1023
1024         list_for_each_entry(one_device,
1025                         &fs_devices->devices, dev_list) {
1026                 if (!one_device->bdev)
1027                         continue;
1028                 disk = one_device->bdev->bd_part;
1029                 disk_kobj = &part_to_dev(disk)->kobj;
1030
1031                 sysfs_remove_link(fs_devices->devices_kobj, disk_kobj->name);
1032         }
1033
1034         return 0;
1035 }
1036
1037 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
1038                                 struct btrfs_device *one_device)
1039 {
1040         int error = 0;
1041         struct btrfs_device *dev;
1042
1043         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
1044                 struct hd_struct *disk;
1045                 struct kobject *disk_kobj;
1046
1047                 if (!dev->bdev)
1048                         continue;
1049
1050                 if (one_device && one_device != dev)
1051                         continue;
1052
1053                 disk = dev->bdev->bd_part;
1054                 disk_kobj = &part_to_dev(disk)->kobj;
1055
1056                 error = sysfs_create_link(fs_devices->devices_kobj,
1057                                           disk_kobj, disk_kobj->name);
1058                 if (error)
1059                         break;
1060         }
1061
1062         return error;
1063 }
1064
1065 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1066 {
1067         int ret;
1068
1069         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
1070         if (ret)
1071                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
1072                         action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
1073                         &disk_to_dev(bdev->bd_disk)->kobj);
1074 }
1075
1076 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices,
1077                                     const u8 *fsid)
1078 {
1079         char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
1080
1081         /*
1082          * Sprouting changes fsid of the mounted filesystem, rename the fsid
1083          * directory
1084          */
1085         snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fsid);
1086         if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
1087                 btrfs_warn(fs_devices->fs_info,
1088                                 "sysfs: failed to create fsid for sprout");
1089 }
1090
1091 /* /sys/fs/btrfs/ entry */
1092 static struct kset *btrfs_kset;
1093
1094 /*
1095  * Creates:
1096  *              /sys/fs/btrfs/UUID
1097  *
1098  * Can be called by the device discovery thread.
1099  */
1100 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
1101 {
1102         int error;
1103
1104         init_completion(&fs_devs->kobj_unregister);
1105         fs_devs->fsid_kobj.kset = btrfs_kset;
1106         error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
1107                                      "%pU", fs_devs->fsid);
1108         if (error) {
1109                 kobject_put(&fs_devs->fsid_kobj);
1110                 return error;
1111         }
1112
1113         fs_devs->devices_kobj = kobject_create_and_add("devices",
1114                                                        &fs_devs->fsid_kobj);
1115         if (!fs_devs->devices_kobj) {
1116                 btrfs_err(fs_devs->fs_info,
1117                           "failed to init sysfs device interface");
1118                 kobject_put(&fs_devs->fsid_kobj);
1119                 return -ENOMEM;
1120         }
1121
1122         return 0;
1123 }
1124
1125 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
1126 {
1127         int error;
1128         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
1129         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
1130
1131         btrfs_set_fs_info_ptr(fs_info);
1132
1133         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
1134         if (error)
1135                 return error;
1136
1137         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
1138         if (error) {
1139                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
1140                 return error;
1141         }
1142
1143         error = sysfs_create_group(fsid_kobj,
1144                                    &btrfs_feature_attr_group);
1145         if (error)
1146                 goto failure;
1147
1148 #ifdef CONFIG_BTRFS_DEBUG
1149         fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
1150         if (!fs_info->debug_kobj) {
1151                 error = -ENOMEM;
1152                 goto failure;
1153         }
1154
1155         error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1156         if (error)
1157                 goto failure;
1158
1159         /* Discard directory */
1160         fs_info->discard_debug_kobj = kobject_create_and_add("discard",
1161                                                      fs_info->debug_kobj);
1162         if (!fs_info->discard_debug_kobj) {
1163                 error = -ENOMEM;
1164                 goto failure;
1165         }
1166
1167         error = sysfs_create_files(fs_info->discard_debug_kobj,
1168                                    discard_debug_attrs);
1169         if (error)
1170                 goto failure;
1171 #endif
1172
1173         error = addrm_unknown_feature_attrs(fs_info, true);
1174         if (error)
1175                 goto failure;
1176
1177         fs_info->space_info_kobj = kobject_create_and_add("allocation",
1178                                                   fsid_kobj);
1179         if (!fs_info->space_info_kobj) {
1180                 error = -ENOMEM;
1181                 goto failure;
1182         }
1183
1184         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
1185         if (error)
1186                 goto failure;
1187
1188         return 0;
1189 failure:
1190         btrfs_sysfs_remove_mounted(fs_info);
1191         return error;
1192 }
1193
1194
1195 /*
1196  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
1197  * values in superblock. Call after any changes to incompat/compat_ro flags
1198  */
1199 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
1200                 u64 bit, enum btrfs_feature_set set)
1201 {
1202         struct btrfs_fs_devices *fs_devs;
1203         struct kobject *fsid_kobj;
1204         u64 features;
1205         int ret;
1206
1207         if (!fs_info)
1208                 return;
1209
1210         features = get_features(fs_info, set);
1211         ASSERT(bit & supported_feature_masks[set]);
1212
1213         fs_devs = fs_info->fs_devices;
1214         fsid_kobj = &fs_devs->fsid_kobj;
1215
1216         if (!fsid_kobj->state_initialized)
1217                 return;
1218
1219         /*
1220          * FIXME: this is too heavy to update just one value, ideally we'd like
1221          * to use sysfs_update_group but some refactoring is needed first.
1222          */
1223         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1224         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
1225 }
1226
1227 int __init btrfs_init_sysfs(void)
1228 {
1229         int ret;
1230
1231         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
1232         if (!btrfs_kset)
1233                 return -ENOMEM;
1234
1235         init_feature_attrs();
1236         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1237         if (ret)
1238                 goto out2;
1239         ret = sysfs_merge_group(&btrfs_kset->kobj,
1240                                 &btrfs_static_feature_attr_group);
1241         if (ret)
1242                 goto out_remove_group;
1243
1244 #ifdef CONFIG_BTRFS_DEBUG
1245         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1246         if (ret)
1247                 goto out2;
1248 #endif
1249
1250         return 0;
1251
1252 out_remove_group:
1253         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1254 out2:
1255         kset_unregister(btrfs_kset);
1256
1257         return ret;
1258 }
1259
1260 void __cold btrfs_exit_sysfs(void)
1261 {
1262         sysfs_unmerge_group(&btrfs_kset->kobj,
1263                             &btrfs_static_feature_attr_group);
1264         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1265 #ifdef CONFIG_BTRFS_DEBUG
1266         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1267 #endif
1268         kset_unregister(btrfs_kset);
1269 }
1270