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_bytes_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, "%lld\n",
 354                         atomic64_read(&fs_info->discard_ctl.discardable_bytes));
 355 }
 356 BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
 357
 358 static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
 359                                               struct kobj_attribute *a,
 360                                               char *buf)
 361 {
 362         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 363
 364         return snprintf(buf, PAGE_SIZE, "%d\n",
 365                         atomic_read(&fs_info->discard_ctl.discardable_extents));
 366 }
 367 BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
 368
 369 static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
 370                                              struct kobj_attribute *a,
 371                                              char *buf)
 372 {
 373         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 374
 375         return snprintf(buf, PAGE_SIZE, "%u\n",
 376                         READ_ONCE(fs_info->discard_ctl.iops_limit));
 377 }
 378
 379 static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
 380                                               struct kobj_attribute *a,
 381                                               const char *buf, size_t len)
 382 {
 383         struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
 384         struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
 385         u32 iops_limit;
 386         int ret;
 387
 388         ret = kstrtou32(buf, 10, &iops_limit);
 389         if (ret)
 390                 return -EINVAL;
 391
 392         WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
 393
 394         return len;
 395 }
 396 BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
 397               btrfs_discard_iops_limit_store);
 398
 399 static const struct attribute *discard_debug_attrs[] = {
 400         BTRFS_ATTR_PTR(discard, discardable_bytes),
 401         BTRFS_ATTR_PTR(discard, discardable_extents),
 402         BTRFS_ATTR_PTR(discard, iops_limit),
 403         NULL,
 404 };
 405
 406 /*
 407  * Runtime debugging exported via sysfs
 408  *
 409  * /sys/fs/btrfs/debug - applies to module or all filesystems
 410  * /sys/fs/btrfs/UUID  - applies only to the given filesystem
 411  */
 412 static const struct attribute *btrfs_debug_mount_attrs[] = {
 413         NULL,
 414 };
 415
 416 static struct attribute *btrfs_debug_feature_attrs[] = {
 417         NULL
 418 };
 419
 420 static const struct attribute_group btrfs_debug_feature_attr_group = {
 421         .name = "debug",
 422         .attrs = btrfs_debug_feature_attrs,
 423 };
 424
 425 #endif
 426
 427 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 428 {
 429         u64 val;
 430         if (lock)
 431                 spin_lock(lock);
 432         val = *value_ptr;
 433         if (lock)
 434                 spin_unlock(lock);
 435         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 436 }
 437
 438 static ssize_t global_rsv_size_show(struct kobject *kobj,
 439                                     struct kobj_attribute *ka, char *buf)
 440 {
 441         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 442         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 443         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 444 }
 445 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 446
 447 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 448                                         struct kobj_attribute *a, char *buf)
 449 {
 450         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 451         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 452         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 453 }
 454 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 455
 456 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 457 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 458
 459 static ssize_t raid_bytes_show(struct kobject *kobj,
 460                                struct kobj_attribute *attr, char *buf);
 461 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 462 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 463
 464 static ssize_t raid_bytes_show(struct kobject *kobj,
 465                                struct kobj_attribute *attr, char *buf)
 466
 467 {
 468         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 469         struct btrfs_block_group *block_group;
 470         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 471         u64 val = 0;
 472
 473         down_read(&sinfo->groups_sem);
 474         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 475                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 476                         val += block_group->length;
 477                 else
 478                         val += block_group->used;
 479         }
 480         up_read(&sinfo->groups_sem);
 481         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 482 }
 483
 484 static struct attribute *raid_attrs[] = {
 485         BTRFS_ATTR_PTR(raid, total_bytes),
 486         BTRFS_ATTR_PTR(raid, used_bytes),
 487         NULL
 488 };
 489 ATTRIBUTE_GROUPS(raid);
 490
 491 static void release_raid_kobj(struct kobject *kobj)
 492 {
 493         kfree(to_raid_kobj(kobj));
 494 }
 495
 496 static struct kobj_type btrfs_raid_ktype = {
 497         .sysfs_ops = &kobj_sysfs_ops,
 498         .release = release_raid_kobj,
 499         .default_groups = raid_groups,
 500 };
 501
 502 #define SPACE_INFO_ATTR(field)                                          \
 503 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 504                                              struct kobj_attribute *a,  \
 505                                              char *buf)                 \
 506 {                                                                       \
 507         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 508         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 509 }                                                                       \
 510 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 511
 512 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 513                                                        struct kobj_attribute *a,
 514                                                        char *buf)
 515 {
 516         struct btrfs_space_info *sinfo = to_space_info(kobj);
 517         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 518         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 519 }
 520
 521 SPACE_INFO_ATTR(flags);
 522 SPACE_INFO_ATTR(total_bytes);
 523 SPACE_INFO_ATTR(bytes_used);
 524 SPACE_INFO_ATTR(bytes_pinned);
 525 SPACE_INFO_ATTR(bytes_reserved);
 526 SPACE_INFO_ATTR(bytes_may_use);
 527 SPACE_INFO_ATTR(bytes_readonly);
 528 SPACE_INFO_ATTR(disk_used);
 529 SPACE_INFO_ATTR(disk_total);
 530 BTRFS_ATTR(space_info, total_bytes_pinned,
 531            btrfs_space_info_show_total_bytes_pinned);
 532
 533 static struct attribute *space_info_attrs[] = {
 534         BTRFS_ATTR_PTR(space_info, flags),
 535         BTRFS_ATTR_PTR(space_info, total_bytes),
 536         BTRFS_ATTR_PTR(space_info, bytes_used),
 537         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 538         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 539         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 540         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 541         BTRFS_ATTR_PTR(space_info, disk_used),
 542         BTRFS_ATTR_PTR(space_info, disk_total),
 543         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 544         NULL,
 545 };
 546 ATTRIBUTE_GROUPS(space_info);
 547
 548 static void space_info_release(struct kobject *kobj)
 549 {
 550         struct btrfs_space_info *sinfo = to_space_info(kobj);
 551         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 552         kfree(sinfo);
 553 }
 554
 555 static struct kobj_type space_info_ktype = {
 556         .sysfs_ops = &kobj_sysfs_ops,
 557         .release = space_info_release,
 558         .default_groups = space_info_groups,
 559 };
 560
 561 static const struct attribute *allocation_attrs[] = {
 562         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 563         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 564         NULL,
 565 };
 566
 567 static ssize_t btrfs_label_show(struct kobject *kobj,
 568                                 struct kobj_attribute *a, char *buf)
 569 {
 570         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 571         char *label = fs_info->super_copy->label;
 572         ssize_t ret;
 573
 574         spin_lock(&fs_info->super_lock);
 575         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 576         spin_unlock(&fs_info->super_lock);
 577
 578         return ret;
 579 }
 580
 581 static ssize_t btrfs_label_store(struct kobject *kobj,
 582                                  struct kobj_attribute *a,
 583                                  const char *buf, size_t len)
 584 {
 585         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 586         size_t p_len;
 587
 588         if (!fs_info)
 589                 return -EPERM;
 590
 591         if (sb_rdonly(fs_info->sb))
 592                 return -EROFS;
 593
 594         /*
 595          * p_len is the len until the first occurrence of either
 596          * '\n' or '\0'
 597          */
 598         p_len = strcspn(buf, "\n");
 599
 600         if (p_len >= BTRFS_LABEL_SIZE)
 601                 return -EINVAL;
 602
 603         spin_lock(&fs_info->super_lock);
 604         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 605         memcpy(fs_info->super_copy->label, buf, p_len);
 606         spin_unlock(&fs_info->super_lock);
 607
 608         /*
 609          * We don't want to do full transaction commit from inside sysfs
 610          */
 611         btrfs_set_pending(fs_info, COMMIT);
 612         wake_up_process(fs_info->transaction_kthread);
 613
 614         return len;
 615 }
 616 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 617
 618 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 619                                 struct kobj_attribute *a, char *buf)
 620 {
 621         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 622
 623         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 624 }
 625
 626 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 627
 628 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 629                                 struct kobj_attribute *a, char *buf)
 630 {
 631         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 632
 633         return snprintf(buf, PAGE_SIZE, "%u\n",
 634                         fs_info->super_copy->sectorsize);
 635 }
 636
 637 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 638
 639 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 640                                 struct kobj_attribute *a, char *buf)
 641 {
 642         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 643
 644         return snprintf(buf, PAGE_SIZE, "%u\n",
 645                         fs_info->super_copy->sectorsize);
 646 }
 647
 648 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 649
 650 static ssize_t quota_override_show(struct kobject *kobj,
 651                                    struct kobj_attribute *a, char *buf)
 652 {
 653         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 654         int quota_override;
 655
 656         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 657         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 658 }
 659
 660 static ssize_t quota_override_store(struct kobject *kobj,
 661                                     struct kobj_attribute *a,
 662                                     const char *buf, size_t len)
 663 {
 664         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 665         unsigned long knob;
 666         int err;
 667
 668         if (!fs_info)
 669                 return -EPERM;
 670
 671         if (!capable(CAP_SYS_RESOURCE))
 672                 return -EPERM;
 673
 674         err = kstrtoul(buf, 10, &knob);
 675         if (err)
 676                 return err;
 677         if (knob > 1)
 678                 return -EINVAL;
 679
 680         if (knob)
 681                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 682         else
 683                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 684
 685         return len;
 686 }
 687
 688 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 689
 690 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 691                                 struct kobj_attribute *a, char *buf)
 692 {
 693         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 694
 695         return snprintf(buf, PAGE_SIZE, "%pU\n",
 696                         fs_info->fs_devices->metadata_uuid);
 697 }
 698
 699 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 700
 701 static ssize_t btrfs_checksum_show(struct kobject *kobj,
 702                                    struct kobj_attribute *a, char *buf)
 703 {
 704         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 705         u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
 706
 707         return snprintf(buf, PAGE_SIZE, "%s (%s)\n",
 708                         btrfs_super_csum_name(csum_type),
 709                         crypto_shash_driver_name(fs_info->csum_shash));
 710 }
 711
 712 BTRFS_ATTR(, checksum, btrfs_checksum_show);
 713
 714 static const struct attribute *btrfs_attrs[] = {
 715         BTRFS_ATTR_PTR(, label),
 716         BTRFS_ATTR_PTR(, nodesize),
 717         BTRFS_ATTR_PTR(, sectorsize),
 718         BTRFS_ATTR_PTR(, clone_alignment),
 719         BTRFS_ATTR_PTR(, quota_override),
 720         BTRFS_ATTR_PTR(, metadata_uuid),
 721         BTRFS_ATTR_PTR(, checksum),
 722         NULL,
 723 };
 724
 725 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 726 {
 727         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 728
 729         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 730         complete(&fs_devs->kobj_unregister);
 731 }
 732
 733 static struct kobj_type btrfs_ktype = {
 734         .sysfs_ops      = &kobj_sysfs_ops,
 735         .release        = btrfs_release_fsid_kobj,
 736 };
 737
 738 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 739 {
 740         if (kobj->ktype != &btrfs_ktype)
 741                 return NULL;
 742         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 743 }
 744
 745 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 746 {
 747         if (kobj->ktype != &btrfs_ktype)
 748                 return NULL;
 749         return to_fs_devs(kobj)->fs_info;
 750 }
 751
 752 #define NUM_FEATURE_BITS 64
 753 #define BTRFS_FEATURE_NAME_MAX 13
 754 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 755 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 756
 757 static const u64 supported_feature_masks[FEAT_MAX] = {
 758         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 759         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 760         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 761 };
 762
 763 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 764 {
 765         int set;
 766
 767         for (set = 0; set < FEAT_MAX; set++) {
 768                 int i;
 769                 struct attribute *attrs[2];
 770                 struct attribute_group agroup = {
 771                         .name = "features",
 772                         .attrs = attrs,
 773                 };
 774                 u64 features = get_features(fs_info, set);
 775                 features &= ~supported_feature_masks[set];
 776
 777                 if (!features)
 778                         continue;
 779
 780                 attrs[1] = NULL;
 781                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 782                         struct btrfs_feature_attr *fa;
 783
 784                         if (!(features & (1ULL << i)))
 785                                 continue;
 786
 787                         fa = &btrfs_feature_attrs[set][i];
 788                         attrs[0] = &fa->kobj_attr.attr;
 789                         if (add) {
 790                                 int ret;
 791                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 792                                                         &agroup);
 793                                 if (ret)
 794                                         return ret;
 795                         } else
 796                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 797                                                     &agroup);
 798                 }
 799
 800         }
 801         return 0;
 802 }
 803
 804 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 805 {
 806         if (fs_devs->devices_kobj) {
 807                 kobject_del(fs_devs->devices_kobj);
 808                 kobject_put(fs_devs->devices_kobj);
 809                 fs_devs->devices_kobj = NULL;
 810         }
 811
 812         if (fs_devs->fsid_kobj.state_initialized) {
 813                 kobject_del(&fs_devs->fsid_kobj);
 814                 kobject_put(&fs_devs->fsid_kobj);
 815                 wait_for_completion(&fs_devs->kobj_unregister);
 816         }
 817 }
 818
 819 /* when fs_devs is NULL it will remove all fsid kobject */
 820 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 821 {
 822         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 823
 824         if (fs_devs) {
 825                 __btrfs_sysfs_remove_fsid(fs_devs);
 826                 return;
 827         }
 828
 829         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 830                 __btrfs_sysfs_remove_fsid(fs_devs);
 831         }
 832 }
 833
 834 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 835 {
 836         btrfs_reset_fs_info_ptr(fs_info);
 837
 838         if (fs_info->space_info_kobj) {
 839                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 840                 kobject_del(fs_info->space_info_kobj);
 841                 kobject_put(fs_info->space_info_kobj);
 842         }
 843 #ifdef CONFIG_BTRFS_DEBUG
 844         if (fs_info->discard_debug_kobj) {
 845                 sysfs_remove_files(fs_info->discard_debug_kobj,
 846                                    discard_debug_attrs);
 847                 kobject_del(fs_info->discard_debug_kobj);
 848                 kobject_put(fs_info->discard_debug_kobj);
 849         }
 850         if (fs_info->debug_kobj) {
 851                 sysfs_remove_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
 852                 kobject_del(fs_info->debug_kobj);
 853                 kobject_put(fs_info->debug_kobj);
 854         }
 855 #endif
 856         addrm_unknown_feature_attrs(fs_info, false);
 857         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 858         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 859         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 860 }
 861
 862 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
 863         [FEAT_COMPAT]    = "compat",
 864         [FEAT_COMPAT_RO] = "compat_ro",
 865         [FEAT_INCOMPAT]  = "incompat",
 866 };
 867
 868 const char * const btrfs_feature_set_name(enum btrfs_feature_set set)
 869 {
 870         return btrfs_feature_set_names[set];
 871 }
 872
 873 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 874 {
 875         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 876         int len = 0;
 877         int i;
 878         char *str;
 879
 880         str = kmalloc(bufsize, GFP_KERNEL);
 881         if (!str)
 882                 return str;
 883
 884         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 885                 const char *name;
 886
 887                 if (!(flags & (1ULL << i)))
 888                         continue;
 889
 890                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 891                 len += snprintf(str + len, bufsize - len, "%s%s",
 892                                 len ? "," : "", name);
 893         }
 894
 895         return str;
 896 }
 897
 898 static void init_feature_attrs(void)
 899 {
 900         struct btrfs_feature_attr *fa;
 901         int set, i;
 902
 903         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 904                      ARRAY_SIZE(btrfs_feature_attrs));
 905         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 906                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 907
 908         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 909         memset(btrfs_unknown_feature_names, 0,
 910                sizeof(btrfs_unknown_feature_names));
 911
 912         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 913                 struct btrfs_feature_attr *sfa;
 914                 struct attribute *a = btrfs_supported_feature_attrs[i];
 915                 int bit;
 916                 sfa = attr_to_btrfs_feature_attr(a);
 917                 bit = ilog2(sfa->feature_bit);
 918                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 919
 920                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 921         }
 922
 923         for (set = 0; set < FEAT_MAX; set++) {
 924                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 925                         char *name = btrfs_unknown_feature_names[set][i];
 926                         fa = &btrfs_feature_attrs[set][i];
 927
 928                         if (fa->kobj_attr.attr.name)
 929                                 continue;
 930
 931                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 932                                  btrfs_feature_set_names[set], i);
 933
 934                         fa->kobj_attr.attr.name = name;
 935                         fa->kobj_attr.attr.mode = S_IRUGO;
 936                         fa->feature_set = set;
 937                         fa->feature_bit = 1ULL << i;
 938                 }
 939         }
 940 }
 941
 942 /*
 943  * Create a sysfs entry for a given block group type at path
 944  * /sys/fs/btrfs/UUID/allocation/data/TYPE
 945  */
 946 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group *cache)
 947 {
 948         struct btrfs_fs_info *fs_info = cache->fs_info;
 949         struct btrfs_space_info *space_info = cache->space_info;
 950         struct raid_kobject *rkobj;
 951         const int index = btrfs_bg_flags_to_raid_index(cache->flags);
 952         unsigned int nofs_flag;
 953         int ret;
 954
 955         /*
 956          * Setup a NOFS context because kobject_add(), deep in its call chain,
 957          * does GFP_KERNEL allocations, and we are often called in a context
 958          * where if reclaim is triggered we can deadlock (we are either holding
 959          * a transaction handle or some lock required for a transaction
 960          * commit).
 961          */
 962         nofs_flag = memalloc_nofs_save();
 963
 964         rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
 965         if (!rkobj) {
 966                 memalloc_nofs_restore(nofs_flag);
 967                 btrfs_warn(cache->fs_info,
 968                                 "couldn't alloc memory for raid level kobject");
 969                 return;
 970         }
 971
 972         rkobj->flags = cache->flags;
 973         kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
 974         ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
 975                           btrfs_bg_type_to_raid_name(rkobj->flags));
 976         memalloc_nofs_restore(nofs_flag);
 977         if (ret) {
 978                 kobject_put(&rkobj->kobj);
 979                 btrfs_warn(fs_info,
 980                         "failed to add kobject for block cache, ignoring");
 981                 return;
 982         }
 983
 984         space_info->block_group_kobjs[index] = &rkobj->kobj;
 985 }
 986
 987 /*
 988  * Remove sysfs directories for all block group types of a given space info and
 989  * the space info as well
 990  */
 991 void btrfs_sysfs_remove_space_info(struct btrfs_space_info *space_info)
 992 {
 993         int i;
 994
 995         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
 996                 struct kobject *kobj;
 997
 998                 kobj = space_info->block_group_kobjs[i];
 999                 space_info->block_group_kobjs[i] = NULL;
1000                 if (kobj) {
1001                         kobject_del(kobj);
1002                         kobject_put(kobj);
1003                 }
1004         }
1005         kobject_del(&space_info->kobj);
1006         kobject_put(&space_info->kobj);
1007 }
1008
1009 static const char *alloc_name(u64 flags)
1010 {
1011         switch (flags) {
1012         case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
1013                 return "mixed";
1014         case BTRFS_BLOCK_GROUP_METADATA:
1015                 return "metadata";
1016         case BTRFS_BLOCK_GROUP_DATA:
1017                 return "data";
1018         case BTRFS_BLOCK_GROUP_SYSTEM:
1019                 return "system";
1020         default:
1021                 WARN_ON(1);
1022                 return "invalid-combination";
1023         };
1024 }
1025
1026 /*
1027  * Create a sysfs entry for a space info type at path
1028  * /sys/fs/btrfs/UUID/allocation/TYPE
1029  */
1030 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
1031                                     struct btrfs_space_info *space_info)
1032 {
1033         int ret;
1034
1035         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
1036                                    fs_info->space_info_kobj, "%s",
1037                                    alloc_name(space_info->flags));
1038         if (ret) {
1039                 kobject_put(&space_info->kobj);
1040                 return ret;
1041         }
1042
1043         return 0;
1044 }
1045
1046 /* when one_device is NULL, it removes all device links */
1047
1048 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
1049                 struct btrfs_device *one_device)
1050 {
1051         struct hd_struct *disk;
1052         struct kobject *disk_kobj;
1053
1054         if (!fs_devices->devices_kobj)
1055                 return -EINVAL;
1056
1057         if (one_device && one_device->bdev) {
1058                 disk = one_device->bdev->bd_part;
1059                 disk_kobj = &part_to_dev(disk)->kobj;
1060
1061                 sysfs_remove_link(fs_devices->devices_kobj, disk_kobj->name);
1062         }
1063
1064         if (one_device)
1065                 return 0;
1066
1067         list_for_each_entry(one_device,
1068                         &fs_devices->devices, dev_list) {
1069                 if (!one_device->bdev)
1070                         continue;
1071                 disk = one_device->bdev->bd_part;
1072                 disk_kobj = &part_to_dev(disk)->kobj;
1073
1074                 sysfs_remove_link(fs_devices->devices_kobj, disk_kobj->name);
1075         }
1076
1077         return 0;
1078 }
1079
1080 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
1081                                 struct btrfs_device *one_device)
1082 {
1083         int error = 0;
1084         struct btrfs_device *dev;
1085
1086         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
1087                 struct hd_struct *disk;
1088                 struct kobject *disk_kobj;
1089
1090                 if (!dev->bdev)
1091                         continue;
1092
1093                 if (one_device && one_device != dev)
1094                         continue;
1095
1096                 disk = dev->bdev->bd_part;
1097                 disk_kobj = &part_to_dev(disk)->kobj;
1098
1099                 error = sysfs_create_link(fs_devices->devices_kobj,
1100                                           disk_kobj, disk_kobj->name);
1101                 if (error)
1102                         break;
1103         }
1104
1105         return error;
1106 }
1107
1108 void btrfs_kobject_uevent(struct block_device *bdev, enum kobject_action action)
1109 {
1110         int ret;
1111
1112         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
1113         if (ret)
1114                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
1115                         action, kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
1116                         &disk_to_dev(bdev->bd_disk)->kobj);
1117 }
1118
1119 void btrfs_sysfs_update_sprout_fsid(struct btrfs_fs_devices *fs_devices,
1120                                     const u8 *fsid)
1121 {
1122         char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
1123
1124         /*
1125          * Sprouting changes fsid of the mounted filesystem, rename the fsid
1126          * directory
1127          */
1128         snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU", fsid);
1129         if (kobject_rename(&fs_devices->fsid_kobj, fsid_buf))
1130                 btrfs_warn(fs_devices->fs_info,
1131                                 "sysfs: failed to create fsid for sprout");
1132 }
1133
1134 /* /sys/fs/btrfs/ entry */
1135 static struct kset *btrfs_kset;
1136
1137 /*
1138  * Creates:
1139  *              /sys/fs/btrfs/UUID
1140  *
1141  * Can be called by the device discovery thread.
1142  */
1143 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
1144 {
1145         int error;
1146
1147         init_completion(&fs_devs->kobj_unregister);
1148         fs_devs->fsid_kobj.kset = btrfs_kset;
1149         error = kobject_init_and_add(&fs_devs->fsid_kobj, &btrfs_ktype, NULL,
1150                                      "%pU", fs_devs->fsid);
1151         if (error) {
1152                 kobject_put(&fs_devs->fsid_kobj);
1153                 return error;
1154         }
1155
1156         fs_devs->devices_kobj = kobject_create_and_add("devices",
1157                                                        &fs_devs->fsid_kobj);
1158         if (!fs_devs->devices_kobj) {
1159                 btrfs_err(fs_devs->fs_info,
1160                           "failed to init sysfs device interface");
1161                 kobject_put(&fs_devs->fsid_kobj);
1162                 return -ENOMEM;
1163         }
1164
1165         return 0;
1166 }
1167
1168 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
1169 {
1170         int error;
1171         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
1172         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
1173
1174         btrfs_set_fs_info_ptr(fs_info);
1175
1176         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
1177         if (error)
1178                 return error;
1179
1180         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
1181         if (error) {
1182                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
1183                 return error;
1184         }
1185
1186         error = sysfs_create_group(fsid_kobj,
1187                                    &btrfs_feature_attr_group);
1188         if (error)
1189                 goto failure;
1190
1191 #ifdef CONFIG_BTRFS_DEBUG
1192         fs_info->debug_kobj = kobject_create_and_add("debug", fsid_kobj);
1193         if (!fs_info->debug_kobj) {
1194                 error = -ENOMEM;
1195                 goto failure;
1196         }
1197
1198         error = sysfs_create_files(fs_info->debug_kobj, btrfs_debug_mount_attrs);
1199         if (error)
1200                 goto failure;
1201
1202         /* Discard directory */
1203         fs_info->discard_debug_kobj = kobject_create_and_add("discard",
1204                                                      fs_info->debug_kobj);
1205         if (!fs_info->discard_debug_kobj) {
1206                 error = -ENOMEM;
1207                 goto failure;
1208         }
1209
1210         error = sysfs_create_files(fs_info->discard_debug_kobj,
1211                                    discard_debug_attrs);
1212         if (error)
1213                 goto failure;
1214 #endif
1215
1216         error = addrm_unknown_feature_attrs(fs_info, true);
1217         if (error)
1218                 goto failure;
1219
1220         fs_info->space_info_kobj = kobject_create_and_add("allocation",
1221                                                   fsid_kobj);
1222         if (!fs_info->space_info_kobj) {
1223                 error = -ENOMEM;
1224                 goto failure;
1225         }
1226
1227         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
1228         if (error)
1229                 goto failure;
1230
1231         return 0;
1232 failure:
1233         btrfs_sysfs_remove_mounted(fs_info);
1234         return error;
1235 }
1236
1237
1238 /*
1239  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
1240  * values in superblock. Call after any changes to incompat/compat_ro flags
1241  */
1242 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
1243                 u64 bit, enum btrfs_feature_set set)
1244 {
1245         struct btrfs_fs_devices *fs_devs;
1246         struct kobject *fsid_kobj;
1247         u64 features;
1248         int ret;
1249
1250         if (!fs_info)
1251                 return;
1252
1253         features = get_features(fs_info, set);
1254         ASSERT(bit & supported_feature_masks[set]);
1255
1256         fs_devs = fs_info->fs_devices;
1257         fsid_kobj = &fs_devs->fsid_kobj;
1258
1259         if (!fsid_kobj->state_initialized)
1260                 return;
1261
1262         /*
1263          * FIXME: this is too heavy to update just one value, ideally we'd like
1264          * to use sysfs_update_group but some refactoring is needed first.
1265          */
1266         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1267         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
1268 }
1269
1270 int __init btrfs_init_sysfs(void)
1271 {
1272         int ret;
1273
1274         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
1275         if (!btrfs_kset)
1276                 return -ENOMEM;
1277
1278         init_feature_attrs();
1279         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1280         if (ret)
1281                 goto out2;
1282         ret = sysfs_merge_group(&btrfs_kset->kobj,
1283                                 &btrfs_static_feature_attr_group);
1284         if (ret)
1285                 goto out_remove_group;
1286
1287 #ifdef CONFIG_BTRFS_DEBUG
1288         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1289         if (ret)
1290                 goto out2;
1291 #endif
1292
1293         return 0;
1294
1295 out_remove_group:
1296         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1297 out2:
1298         kset_unregister(btrfs_kset);
1299
1300         return ret;
1301 }
1302
1303 void __cold btrfs_exit_sysfs(void)
1304 {
1305         sysfs_unmerge_group(&btrfs_kset->kobj,
1306                             &btrfs_static_feature_attr_group);
1307         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1308 #ifdef CONFIG_BTRFS_DEBUG
1309         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1310 #endif
1311         kset_unregister(btrfs_kset);
1312 }
1313