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/slab.h>
   8 #include <linux/spinlock.h>
   9 #include <linux/completion.h>
  10 #include <linux/kobject.h>
  11 #include <linux/bug.h>
  12 #include <linux/debugfs.h>
  13
  14 #include "ctree.h"
  15 #include "disk-io.h"
  16 #include "transaction.h"
  17 #include "sysfs.h"
  18 #include "volumes.h"
  19
  20 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  21 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
  22
  23 static u64 get_features(struct btrfs_fs_info *fs_info,
  24                         enum btrfs_feature_set set)
  25 {
  26         struct btrfs_super_block *disk_super = fs_info->super_copy;
  27         if (set == FEAT_COMPAT)
  28                 return btrfs_super_compat_flags(disk_super);
  29         else if (set == FEAT_COMPAT_RO)
  30                 return btrfs_super_compat_ro_flags(disk_super);
  31         else
  32                 return btrfs_super_incompat_flags(disk_super);
  33 }
  34
  35 static void set_features(struct btrfs_fs_info *fs_info,
  36                          enum btrfs_feature_set set, u64 features)
  37 {
  38         struct btrfs_super_block *disk_super = fs_info->super_copy;
  39         if (set == FEAT_COMPAT)
  40                 btrfs_set_super_compat_flags(disk_super, features);
  41         else if (set == FEAT_COMPAT_RO)
  42                 btrfs_set_super_compat_ro_flags(disk_super, features);
  43         else
  44                 btrfs_set_super_incompat_flags(disk_super, features);
  45 }
  46
  47 static int can_modify_feature(struct btrfs_feature_attr *fa)
  48 {
  49         int val = 0;
  50         u64 set, clear;
  51         switch (fa->feature_set) {
  52         case FEAT_COMPAT:
  53                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  54                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  55                 break;
  56         case FEAT_COMPAT_RO:
  57                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  58                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  59                 break;
  60         case FEAT_INCOMPAT:
  61                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  62                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  63                 break;
  64         default:
  65                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
  66                                 fa->feature_set);
  67                 return 0;
  68         }
  69
  70         if (set & fa->feature_bit)
  71                 val |= 1;
  72         if (clear & fa->feature_bit)
  73                 val |= 2;
  74
  75         return val;
  76 }
  77
  78 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  79                                        struct kobj_attribute *a, char *buf)
  80 {
  81         int val = 0;
  82         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  83         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
  84         if (fs_info) {
  85                 u64 features = get_features(fs_info, fa->feature_set);
  86                 if (features & fa->feature_bit)
  87                         val = 1;
  88         } else
  89                 val = can_modify_feature(fa);
  90
  91         return snprintf(buf, PAGE_SIZE, "%d\n", val);
  92 }
  93
  94 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
  95                                         struct kobj_attribute *a,
  96                                         const char *buf, size_t count)
  97 {
  98         struct btrfs_fs_info *fs_info;
  99         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 100         u64 features, set, clear;
 101         unsigned long val;
 102         int ret;
 103
 104         fs_info = to_fs_info(kobj);
 105         if (!fs_info)
 106                 return -EPERM;
 107
 108         if (sb_rdonly(fs_info->sb))
 109                 return -EROFS;
 110
 111         ret = kstrtoul(skip_spaces(buf), 0, &val);
 112         if (ret)
 113                 return ret;
 114
 115         if (fa->feature_set == FEAT_COMPAT) {
 116                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 117                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 118         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 119                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 120                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 121         } else {
 122                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 123                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 124         }
 125
 126         features = get_features(fs_info, fa->feature_set);
 127
 128         /* Nothing to do */
 129         if ((val && (features & fa->feature_bit)) ||
 130             (!val && !(features & fa->feature_bit)))
 131                 return count;
 132
 133         if ((val && !(set & fa->feature_bit)) ||
 134             (!val && !(clear & fa->feature_bit))) {
 135                 btrfs_info(fs_info,
 136                         "%sabling feature %s on mounted fs is not supported.",
 137                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 138                 return -EPERM;
 139         }
 140
 141         btrfs_info(fs_info, "%s %s feature flag",
 142                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 143
 144         spin_lock(&fs_info->super_lock);
 145         features = get_features(fs_info, fa->feature_set);
 146         if (val)
 147                 features |= fa->feature_bit;
 148         else
 149                 features &= ~fa->feature_bit;
 150         set_features(fs_info, fa->feature_set, features);
 151         spin_unlock(&fs_info->super_lock);
 152
 153         /*
 154          * We don't want to do full transaction commit from inside sysfs
 155          */
 156         btrfs_set_pending(fs_info, COMMIT);
 157         wake_up_process(fs_info->transaction_kthread);
 158
 159         return count;
 160 }
 161
 162 static umode_t btrfs_feature_visible(struct kobject *kobj,
 163                                      struct attribute *attr, int unused)
 164 {
 165         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 166         umode_t mode = attr->mode;
 167
 168         if (fs_info) {
 169                 struct btrfs_feature_attr *fa;
 170                 u64 features;
 171
 172                 fa = attr_to_btrfs_feature_attr(attr);
 173                 features = get_features(fs_info, fa->feature_set);
 174
 175                 if (can_modify_feature(fa))
 176                         mode |= S_IWUSR;
 177                 else if (!(features & fa->feature_bit))
 178                         mode = 0;
 179         }
 180
 181         return mode;
 182 }
 183
 184 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 185 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 186 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 187 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 188 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
 189 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 190 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 191 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 192 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 193 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 194 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 195
 196 static struct attribute *btrfs_supported_feature_attrs[] = {
 197         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 198         BTRFS_FEAT_ATTR_PTR(default_subvol),
 199         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 200         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 201         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 202         BTRFS_FEAT_ATTR_PTR(big_metadata),
 203         BTRFS_FEAT_ATTR_PTR(extended_iref),
 204         BTRFS_FEAT_ATTR_PTR(raid56),
 205         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 206         BTRFS_FEAT_ATTR_PTR(no_holes),
 207         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 208         NULL
 209 };
 210
 211 /*
 212  * Features which depend on feature bits and may differ between each fs.
 213  *
 214  * /sys/fs/btrfs/features lists all available features of this kernel while
 215  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 216  * can be changed online.
 217  */
 218 static const struct attribute_group btrfs_feature_attr_group = {
 219         .name = "features",
 220         .is_visible = btrfs_feature_visible,
 221         .attrs = btrfs_supported_feature_attrs,
 222 };
 223
 224 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 225                                  struct kobj_attribute *ka, char *buf)
 226 {
 227         return snprintf(buf, PAGE_SIZE, "0\n");
 228 }
 229 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 230
 231 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 232         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 233         NULL
 234 };
 235
 236 /*
 237  * Features which only depend on kernel version.
 238  *
 239  * These are listed in /sys/fs/btrfs/features along with
 240  * btrfs_feature_attr_group
 241  */
 242 static const struct attribute_group btrfs_static_feature_attr_group = {
 243         .name = "features",
 244         .attrs = btrfs_supported_static_feature_attrs,
 245 };
 246
 247 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 248 {
 249         u64 val;
 250         if (lock)
 251                 spin_lock(lock);
 252         val = *value_ptr;
 253         if (lock)
 254                 spin_unlock(lock);
 255         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 256 }
 257
 258 static ssize_t global_rsv_size_show(struct kobject *kobj,
 259                                     struct kobj_attribute *ka, char *buf)
 260 {
 261         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 262         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 263         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 264 }
 265 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 266
 267 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 268                                         struct kobj_attribute *a, char *buf)
 269 {
 270         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 271         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 272         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 273 }
 274 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 275
 276 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 277 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 278
 279 static ssize_t raid_bytes_show(struct kobject *kobj,
 280                                struct kobj_attribute *attr, char *buf);
 281 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 282 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 283
 284 static ssize_t raid_bytes_show(struct kobject *kobj,
 285                                struct kobj_attribute *attr, char *buf)
 286
 287 {
 288         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 289         struct btrfs_block_group_cache *block_group;
 290         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 291         u64 val = 0;
 292
 293         down_read(&sinfo->groups_sem);
 294         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 295                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 296                         val += block_group->key.offset;
 297                 else
 298                         val += btrfs_block_group_used(&block_group->item);
 299         }
 300         up_read(&sinfo->groups_sem);
 301         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 302 }
 303
 304 static struct attribute *raid_attributes[] = {
 305         BTRFS_ATTR_PTR(raid, total_bytes),
 306         BTRFS_ATTR_PTR(raid, used_bytes),
 307         NULL
 308 };
 309
 310 static void release_raid_kobj(struct kobject *kobj)
 311 {
 312         kfree(to_raid_kobj(kobj));
 313 }
 314
 315 struct kobj_type btrfs_raid_ktype = {
 316         .sysfs_ops = &kobj_sysfs_ops,
 317         .release = release_raid_kobj,
 318         .default_attrs = raid_attributes,
 319 };
 320
 321 #define SPACE_INFO_ATTR(field)                                          \
 322 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 323                                              struct kobj_attribute *a,  \
 324                                              char *buf)                 \
 325 {                                                                       \
 326         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 327         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 328 }                                                                       \
 329 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 330
 331 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 332                                                        struct kobj_attribute *a,
 333                                                        char *buf)
 334 {
 335         struct btrfs_space_info *sinfo = to_space_info(kobj);
 336         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 337         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 338 }
 339
 340 SPACE_INFO_ATTR(flags);
 341 SPACE_INFO_ATTR(total_bytes);
 342 SPACE_INFO_ATTR(bytes_used);
 343 SPACE_INFO_ATTR(bytes_pinned);
 344 SPACE_INFO_ATTR(bytes_reserved);
 345 SPACE_INFO_ATTR(bytes_may_use);
 346 SPACE_INFO_ATTR(bytes_readonly);
 347 SPACE_INFO_ATTR(disk_used);
 348 SPACE_INFO_ATTR(disk_total);
 349 BTRFS_ATTR(space_info, total_bytes_pinned,
 350            btrfs_space_info_show_total_bytes_pinned);
 351
 352 static struct attribute *space_info_attrs[] = {
 353         BTRFS_ATTR_PTR(space_info, flags),
 354         BTRFS_ATTR_PTR(space_info, total_bytes),
 355         BTRFS_ATTR_PTR(space_info, bytes_used),
 356         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 357         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 358         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 359         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 360         BTRFS_ATTR_PTR(space_info, disk_used),
 361         BTRFS_ATTR_PTR(space_info, disk_total),
 362         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 363         NULL,
 364 };
 365
 366 static void space_info_release(struct kobject *kobj)
 367 {
 368         struct btrfs_space_info *sinfo = to_space_info(kobj);
 369         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 370         kfree(sinfo);
 371 }
 372
 373 struct kobj_type space_info_ktype = {
 374         .sysfs_ops = &kobj_sysfs_ops,
 375         .release = space_info_release,
 376         .default_attrs = space_info_attrs,
 377 };
 378
 379 static const struct attribute *allocation_attrs[] = {
 380         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 381         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 382         NULL,
 383 };
 384
 385 static ssize_t btrfs_label_show(struct kobject *kobj,
 386                                 struct kobj_attribute *a, char *buf)
 387 {
 388         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 389         char *label = fs_info->super_copy->label;
 390         ssize_t ret;
 391
 392         spin_lock(&fs_info->super_lock);
 393         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 394         spin_unlock(&fs_info->super_lock);
 395
 396         return ret;
 397 }
 398
 399 static ssize_t btrfs_label_store(struct kobject *kobj,
 400                                  struct kobj_attribute *a,
 401                                  const char *buf, size_t len)
 402 {
 403         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 404         size_t p_len;
 405
 406         if (!fs_info)
 407                 return -EPERM;
 408
 409         if (sb_rdonly(fs_info->sb))
 410                 return -EROFS;
 411
 412         /*
 413          * p_len is the len until the first occurrence of either
 414          * '\n' or '\0'
 415          */
 416         p_len = strcspn(buf, "\n");
 417
 418         if (p_len >= BTRFS_LABEL_SIZE)
 419                 return -EINVAL;
 420
 421         spin_lock(&fs_info->super_lock);
 422         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 423         memcpy(fs_info->super_copy->label, buf, p_len);
 424         spin_unlock(&fs_info->super_lock);
 425
 426         /*
 427          * We don't want to do full transaction commit from inside sysfs
 428          */
 429         btrfs_set_pending(fs_info, COMMIT);
 430         wake_up_process(fs_info->transaction_kthread);
 431
 432         return len;
 433 }
 434 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 435
 436 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 437                                 struct kobj_attribute *a, char *buf)
 438 {
 439         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 440
 441         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 442 }
 443
 444 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 445
 446 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 447                                 struct kobj_attribute *a, char *buf)
 448 {
 449         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 450
 451         return snprintf(buf, PAGE_SIZE, "%u\n",
 452                         fs_info->super_copy->sectorsize);
 453 }
 454
 455 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 456
 457 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 458                                 struct kobj_attribute *a, char *buf)
 459 {
 460         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 461
 462         return snprintf(buf, PAGE_SIZE, "%u\n",
 463                         fs_info->super_copy->sectorsize);
 464 }
 465
 466 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 467
 468 static ssize_t quota_override_show(struct kobject *kobj,
 469                                    struct kobj_attribute *a, char *buf)
 470 {
 471         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 472         int quota_override;
 473
 474         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 475         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 476 }
 477
 478 static ssize_t quota_override_store(struct kobject *kobj,
 479                                     struct kobj_attribute *a,
 480                                     const char *buf, size_t len)
 481 {
 482         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 483         unsigned long knob;
 484         int err;
 485
 486         if (!fs_info)
 487                 return -EPERM;
 488
 489         if (!capable(CAP_SYS_RESOURCE))
 490                 return -EPERM;
 491
 492         err = kstrtoul(buf, 10, &knob);
 493         if (err)
 494                 return err;
 495         if (knob > 1)
 496                 return -EINVAL;
 497
 498         if (knob)
 499                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 500         else
 501                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 502
 503         return len;
 504 }
 505
 506 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 507
 508 static const struct attribute *btrfs_attrs[] = {
 509         BTRFS_ATTR_PTR(, label),
 510         BTRFS_ATTR_PTR(, nodesize),
 511         BTRFS_ATTR_PTR(, sectorsize),
 512         BTRFS_ATTR_PTR(, clone_alignment),
 513         BTRFS_ATTR_PTR(, quota_override),
 514         NULL,
 515 };
 516
 517 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 518 {
 519         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 520
 521         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 522         complete(&fs_devs->kobj_unregister);
 523 }
 524
 525 static struct kobj_type btrfs_ktype = {
 526         .sysfs_ops      = &kobj_sysfs_ops,
 527         .release        = btrfs_release_fsid_kobj,
 528 };
 529
 530 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 531 {
 532         if (kobj->ktype != &btrfs_ktype)
 533                 return NULL;
 534         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 535 }
 536
 537 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 538 {
 539         if (kobj->ktype != &btrfs_ktype)
 540                 return NULL;
 541         return to_fs_devs(kobj)->fs_info;
 542 }
 543
 544 #define NUM_FEATURE_BITS 64
 545 #define BTRFS_FEATURE_NAME_MAX 13
 546 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 547 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 548
 549 static const u64 supported_feature_masks[FEAT_MAX] = {
 550         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 551         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 552         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 553 };
 554
 555 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 556 {
 557         int set;
 558
 559         for (set = 0; set < FEAT_MAX; set++) {
 560                 int i;
 561                 struct attribute *attrs[2];
 562                 struct attribute_group agroup = {
 563                         .name = "features",
 564                         .attrs = attrs,
 565                 };
 566                 u64 features = get_features(fs_info, set);
 567                 features &= ~supported_feature_masks[set];
 568
 569                 if (!features)
 570                         continue;
 571
 572                 attrs[1] = NULL;
 573                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 574                         struct btrfs_feature_attr *fa;
 575
 576                         if (!(features & (1ULL << i)))
 577                                 continue;
 578
 579                         fa = &btrfs_feature_attrs[set][i];
 580                         attrs[0] = &fa->kobj_attr.attr;
 581                         if (add) {
 582                                 int ret;
 583                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 584                                                         &agroup);
 585                                 if (ret)
 586                                         return ret;
 587                         } else
 588                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 589                                                     &agroup);
 590                 }
 591
 592         }
 593         return 0;
 594 }
 595
 596 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 597 {
 598         if (fs_devs->device_dir_kobj) {
 599                 kobject_del(fs_devs->device_dir_kobj);
 600                 kobject_put(fs_devs->device_dir_kobj);
 601                 fs_devs->device_dir_kobj = NULL;
 602         }
 603
 604         if (fs_devs->fsid_kobj.state_initialized) {
 605                 kobject_del(&fs_devs->fsid_kobj);
 606                 kobject_put(&fs_devs->fsid_kobj);
 607                 wait_for_completion(&fs_devs->kobj_unregister);
 608         }
 609 }
 610
 611 /* when fs_devs is NULL it will remove all fsid kobject */
 612 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 613 {
 614         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 615
 616         if (fs_devs) {
 617                 __btrfs_sysfs_remove_fsid(fs_devs);
 618                 return;
 619         }
 620
 621         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 622                 __btrfs_sysfs_remove_fsid(fs_devs);
 623         }
 624 }
 625
 626 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 627 {
 628         btrfs_reset_fs_info_ptr(fs_info);
 629
 630         if (fs_info->space_info_kobj) {
 631                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 632                 kobject_del(fs_info->space_info_kobj);
 633                 kobject_put(fs_info->space_info_kobj);
 634         }
 635         addrm_unknown_feature_attrs(fs_info, false);
 636         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 637         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 638         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 639 }
 640
 641 const char * const btrfs_feature_set_names[FEAT_MAX] = {
 642         [FEAT_COMPAT]    = "compat",
 643         [FEAT_COMPAT_RO] = "compat_ro",
 644         [FEAT_INCOMPAT]  = "incompat",
 645 };
 646
 647 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 648 {
 649         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 650         int len = 0;
 651         int i;
 652         char *str;
 653
 654         str = kmalloc(bufsize, GFP_KERNEL);
 655         if (!str)
 656                 return str;
 657
 658         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 659                 const char *name;
 660
 661                 if (!(flags & (1ULL << i)))
 662                         continue;
 663
 664                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 665                 len += snprintf(str + len, bufsize - len, "%s%s",
 666                                 len ? "," : "", name);
 667         }
 668
 669         return str;
 670 }
 671
 672 static void init_feature_attrs(void)
 673 {
 674         struct btrfs_feature_attr *fa;
 675         int set, i;
 676
 677         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 678                      ARRAY_SIZE(btrfs_feature_attrs));
 679         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 680                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 681
 682         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 683         memset(btrfs_unknown_feature_names, 0,
 684                sizeof(btrfs_unknown_feature_names));
 685
 686         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 687                 struct btrfs_feature_attr *sfa;
 688                 struct attribute *a = btrfs_supported_feature_attrs[i];
 689                 int bit;
 690                 sfa = attr_to_btrfs_feature_attr(a);
 691                 bit = ilog2(sfa->feature_bit);
 692                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 693
 694                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 695         }
 696
 697         for (set = 0; set < FEAT_MAX; set++) {
 698                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 699                         char *name = btrfs_unknown_feature_names[set][i];
 700                         fa = &btrfs_feature_attrs[set][i];
 701
 702                         if (fa->kobj_attr.attr.name)
 703                                 continue;
 704
 705                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 706                                  btrfs_feature_set_names[set], i);
 707
 708                         fa->kobj_attr.attr.name = name;
 709                         fa->kobj_attr.attr.mode = S_IRUGO;
 710                         fa->feature_set = set;
 711                         fa->feature_bit = 1ULL << i;
 712                 }
 713         }
 714 }
 715
 716 /* when one_device is NULL, it removes all device links */
 717
 718 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 719                 struct btrfs_device *one_device)
 720 {
 721         struct hd_struct *disk;
 722         struct kobject *disk_kobj;
 723
 724         if (!fs_devices->device_dir_kobj)
 725                 return -EINVAL;
 726
 727         if (one_device && one_device->bdev) {
 728                 disk = one_device->bdev->bd_part;
 729                 disk_kobj = &part_to_dev(disk)->kobj;
 730
 731                 sysfs_remove_link(fs_devices->device_dir_kobj,
 732                                                 disk_kobj->name);
 733         }
 734
 735         if (one_device)
 736                 return 0;
 737
 738         list_for_each_entry(one_device,
 739                         &fs_devices->devices, dev_list) {
 740                 if (!one_device->bdev)
 741                         continue;
 742                 disk = one_device->bdev->bd_part;
 743                 disk_kobj = &part_to_dev(disk)->kobj;
 744
 745                 sysfs_remove_link(fs_devices->device_dir_kobj,
 746                                                 disk_kobj->name);
 747         }
 748
 749         return 0;
 750 }
 751
 752 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 753 {
 754         if (!fs_devs->device_dir_kobj)
 755                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 756                                                 &fs_devs->fsid_kobj);
 757
 758         if (!fs_devs->device_dir_kobj)
 759                 return -ENOMEM;
 760
 761         return 0;
 762 }
 763
 764 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 765                                 struct btrfs_device *one_device)
 766 {
 767         int error = 0;
 768         struct btrfs_device *dev;
 769
 770         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 771                 struct hd_struct *disk;
 772                 struct kobject *disk_kobj;
 773
 774                 if (!dev->bdev)
 775                         continue;
 776
 777                 if (one_device && one_device != dev)
 778                         continue;
 779
 780                 disk = dev->bdev->bd_part;
 781                 disk_kobj = &part_to_dev(disk)->kobj;
 782
 783                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 784                                           disk_kobj, disk_kobj->name);
 785                 if (error)
 786                         break;
 787         }
 788
 789         return error;
 790 }
 791
 792 /* /sys/fs/btrfs/ entry */
 793 static struct kset *btrfs_kset;
 794
 795 /* /sys/kernel/debug/btrfs */
 796 static struct dentry *btrfs_debugfs_root_dentry;
 797
 798 /* Debugging tunables and exported data */
 799 u64 btrfs_debugfs_test;
 800
 801 /*
 802  * Can be called by the device discovery thread.
 803  * And parent can be specified for seed device
 804  */
 805 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 806                                 struct kobject *parent)
 807 {
 808         int error;
 809
 810         init_completion(&fs_devs->kobj_unregister);
 811         fs_devs->fsid_kobj.kset = btrfs_kset;
 812         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 813                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 814         if (error) {
 815                 kobject_put(&fs_devs->fsid_kobj);
 816                 return error;
 817         }
 818
 819         return 0;
 820 }
 821
 822 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 823 {
 824         int error;
 825         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 826         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 827
 828         btrfs_set_fs_info_ptr(fs_info);
 829
 830         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 831         if (error)
 832                 return error;
 833
 834         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 835         if (error) {
 836                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 837                 return error;
 838         }
 839
 840         error = sysfs_create_group(fsid_kobj,
 841                                    &btrfs_feature_attr_group);
 842         if (error)
 843                 goto failure;
 844
 845         error = addrm_unknown_feature_attrs(fs_info, true);
 846         if (error)
 847                 goto failure;
 848
 849         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 850                                                   fsid_kobj);
 851         if (!fs_info->space_info_kobj) {
 852                 error = -ENOMEM;
 853                 goto failure;
 854         }
 855
 856         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 857         if (error)
 858                 goto failure;
 859
 860         return 0;
 861 failure:
 862         btrfs_sysfs_remove_mounted(fs_info);
 863         return error;
 864 }
 865
 866
 867 /*
 868  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 869  * values in superblock. Call after any changes to incompat/compat_ro flags
 870  */
 871 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 872                 u64 bit, enum btrfs_feature_set set)
 873 {
 874         struct btrfs_fs_devices *fs_devs;
 875         struct kobject *fsid_kobj;
 876         u64 features;
 877         int ret;
 878
 879         if (!fs_info)
 880                 return;
 881
 882         features = get_features(fs_info, set);
 883         ASSERT(bit & supported_feature_masks[set]);
 884
 885         fs_devs = fs_info->fs_devices;
 886         fsid_kobj = &fs_devs->fsid_kobj;
 887
 888         if (!fsid_kobj->state_initialized)
 889                 return;
 890
 891         /*
 892          * FIXME: this is too heavy to update just one value, ideally we'd like
 893          * to use sysfs_update_group but some refactoring is needed first.
 894          */
 895         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 896         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 897 }
 898
 899 static int btrfs_init_debugfs(void)
 900 {
 901 #ifdef CONFIG_DEBUG_FS
 902         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 903         if (!btrfs_debugfs_root_dentry)
 904                 return -ENOMEM;
 905
 906         /*
 907          * Example code, how to export data through debugfs.
 908          *
 909          * file:        /sys/kernel/debug/btrfs/test
 910          * contents of: btrfs_debugfs_test
 911          */
 912 #ifdef CONFIG_BTRFS_DEBUG
 913         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
 914                         &btrfs_debugfs_test);
 915 #endif
 916
 917 #endif
 918         return 0;
 919 }
 920
 921 int __init btrfs_init_sysfs(void)
 922 {
 923         int ret;
 924
 925         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 926         if (!btrfs_kset)
 927                 return -ENOMEM;
 928
 929         ret = btrfs_init_debugfs();
 930         if (ret)
 931                 goto out1;
 932
 933         init_feature_attrs();
 934         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 935         if (ret)
 936                 goto out2;
 937         ret = sysfs_merge_group(&btrfs_kset->kobj,
 938                                 &btrfs_static_feature_attr_group);
 939         if (ret)
 940                 goto out_remove_group;
 941
 942         return 0;
 943
 944 out_remove_group:
 945         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 946 out2:
 947         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 948 out1:
 949         kset_unregister(btrfs_kset);
 950
 951         return ret;
 952 }
 953
 954 void __cold btrfs_exit_sysfs(void)
 955 {
 956         sysfs_unmerge_group(&btrfs_kset->kobj,
 957                             &btrfs_static_feature_attr_group);
 958         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 959         kset_unregister(btrfs_kset);
 960         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 961 }
 962