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_INCOMPAT(metadata_uuid, METADATA_UUID);
 195 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 196
 197 static struct attribute *btrfs_supported_feature_attrs[] = {
 198         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 199         BTRFS_FEAT_ATTR_PTR(default_subvol),
 200         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 201         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 202         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 203         BTRFS_FEAT_ATTR_PTR(big_metadata),
 204         BTRFS_FEAT_ATTR_PTR(extended_iref),
 205         BTRFS_FEAT_ATTR_PTR(raid56),
 206         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 207         BTRFS_FEAT_ATTR_PTR(no_holes),
 208         BTRFS_FEAT_ATTR_PTR(metadata_uuid),
 209         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 210         NULL
 211 };
 212
 213 /*
 214  * Features which depend on feature bits and may differ between each fs.
 215  *
 216  * /sys/fs/btrfs/features lists all available features of this kernel while
 217  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 218  * can be changed online.
 219  */
 220 static const struct attribute_group btrfs_feature_attr_group = {
 221         .name = "features",
 222         .is_visible = btrfs_feature_visible,
 223         .attrs = btrfs_supported_feature_attrs,
 224 };
 225
 226 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 227                                  struct kobj_attribute *ka, char *buf)
 228 {
 229         return snprintf(buf, PAGE_SIZE, "0\n");
 230 }
 231 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 232
 233 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 234         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 235         NULL
 236 };
 237
 238 /*
 239  * Features which only depend on kernel version.
 240  *
 241  * These are listed in /sys/fs/btrfs/features along with
 242  * btrfs_feature_attr_group
 243  */
 244 static const struct attribute_group btrfs_static_feature_attr_group = {
 245         .name = "features",
 246         .attrs = btrfs_supported_static_feature_attrs,
 247 };
 248
 249 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 250 {
 251         u64 val;
 252         if (lock)
 253                 spin_lock(lock);
 254         val = *value_ptr;
 255         if (lock)
 256                 spin_unlock(lock);
 257         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 258 }
 259
 260 static ssize_t global_rsv_size_show(struct kobject *kobj,
 261                                     struct kobj_attribute *ka, char *buf)
 262 {
 263         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 264         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 265         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 266 }
 267 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 268
 269 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 270                                         struct kobj_attribute *a, char *buf)
 271 {
 272         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 273         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 274         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 275 }
 276 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 277
 278 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 279 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 280
 281 static ssize_t raid_bytes_show(struct kobject *kobj,
 282                                struct kobj_attribute *attr, char *buf);
 283 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 284 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 285
 286 static ssize_t raid_bytes_show(struct kobject *kobj,
 287                                struct kobj_attribute *attr, char *buf)
 288
 289 {
 290         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 291         struct btrfs_block_group_cache *block_group;
 292         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 293         u64 val = 0;
 294
 295         down_read(&sinfo->groups_sem);
 296         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 297                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 298                         val += block_group->key.offset;
 299                 else
 300                         val += btrfs_block_group_used(&block_group->item);
 301         }
 302         up_read(&sinfo->groups_sem);
 303         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 304 }
 305
 306 static struct attribute *raid_attributes[] = {
 307         BTRFS_ATTR_PTR(raid, total_bytes),
 308         BTRFS_ATTR_PTR(raid, used_bytes),
 309         NULL
 310 };
 311
 312 static void release_raid_kobj(struct kobject *kobj)
 313 {
 314         kfree(to_raid_kobj(kobj));
 315 }
 316
 317 struct kobj_type btrfs_raid_ktype = {
 318         .sysfs_ops = &kobj_sysfs_ops,
 319         .release = release_raid_kobj,
 320         .default_attrs = raid_attributes,
 321 };
 322
 323 #define SPACE_INFO_ATTR(field)                                          \
 324 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 325                                              struct kobj_attribute *a,  \
 326                                              char *buf)                 \
 327 {                                                                       \
 328         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 329         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 330 }                                                                       \
 331 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 332
 333 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 334                                                        struct kobj_attribute *a,
 335                                                        char *buf)
 336 {
 337         struct btrfs_space_info *sinfo = to_space_info(kobj);
 338         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 339         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 340 }
 341
 342 SPACE_INFO_ATTR(flags);
 343 SPACE_INFO_ATTR(total_bytes);
 344 SPACE_INFO_ATTR(bytes_used);
 345 SPACE_INFO_ATTR(bytes_pinned);
 346 SPACE_INFO_ATTR(bytes_reserved);
 347 SPACE_INFO_ATTR(bytes_may_use);
 348 SPACE_INFO_ATTR(bytes_readonly);
 349 SPACE_INFO_ATTR(disk_used);
 350 SPACE_INFO_ATTR(disk_total);
 351 BTRFS_ATTR(space_info, total_bytes_pinned,
 352            btrfs_space_info_show_total_bytes_pinned);
 353
 354 static struct attribute *space_info_attrs[] = {
 355         BTRFS_ATTR_PTR(space_info, flags),
 356         BTRFS_ATTR_PTR(space_info, total_bytes),
 357         BTRFS_ATTR_PTR(space_info, bytes_used),
 358         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 359         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 360         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 361         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 362         BTRFS_ATTR_PTR(space_info, disk_used),
 363         BTRFS_ATTR_PTR(space_info, disk_total),
 364         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 365         NULL,
 366 };
 367
 368 static void space_info_release(struct kobject *kobj)
 369 {
 370         struct btrfs_space_info *sinfo = to_space_info(kobj);
 371         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 372         kfree(sinfo);
 373 }
 374
 375 struct kobj_type space_info_ktype = {
 376         .sysfs_ops = &kobj_sysfs_ops,
 377         .release = space_info_release,
 378         .default_attrs = space_info_attrs,
 379 };
 380
 381 static const struct attribute *allocation_attrs[] = {
 382         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 383         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 384         NULL,
 385 };
 386
 387 static ssize_t btrfs_label_show(struct kobject *kobj,
 388                                 struct kobj_attribute *a, char *buf)
 389 {
 390         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 391         char *label = fs_info->super_copy->label;
 392         ssize_t ret;
 393
 394         spin_lock(&fs_info->super_lock);
 395         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 396         spin_unlock(&fs_info->super_lock);
 397
 398         return ret;
 399 }
 400
 401 static ssize_t btrfs_label_store(struct kobject *kobj,
 402                                  struct kobj_attribute *a,
 403                                  const char *buf, size_t len)
 404 {
 405         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 406         size_t p_len;
 407
 408         if (!fs_info)
 409                 return -EPERM;
 410
 411         if (sb_rdonly(fs_info->sb))
 412                 return -EROFS;
 413
 414         /*
 415          * p_len is the len until the first occurrence of either
 416          * '\n' or '\0'
 417          */
 418         p_len = strcspn(buf, "\n");
 419
 420         if (p_len >= BTRFS_LABEL_SIZE)
 421                 return -EINVAL;
 422
 423         spin_lock(&fs_info->super_lock);
 424         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 425         memcpy(fs_info->super_copy->label, buf, p_len);
 426         spin_unlock(&fs_info->super_lock);
 427
 428         /*
 429          * We don't want to do full transaction commit from inside sysfs
 430          */
 431         btrfs_set_pending(fs_info, COMMIT);
 432         wake_up_process(fs_info->transaction_kthread);
 433
 434         return len;
 435 }
 436 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 437
 438 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 439                                 struct kobj_attribute *a, char *buf)
 440 {
 441         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 442
 443         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 444 }
 445
 446 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 447
 448 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 449                                 struct kobj_attribute *a, char *buf)
 450 {
 451         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 452
 453         return snprintf(buf, PAGE_SIZE, "%u\n",
 454                         fs_info->super_copy->sectorsize);
 455 }
 456
 457 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 458
 459 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 460                                 struct kobj_attribute *a, char *buf)
 461 {
 462         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 463
 464         return snprintf(buf, PAGE_SIZE, "%u\n",
 465                         fs_info->super_copy->sectorsize);
 466 }
 467
 468 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 469
 470 static ssize_t quota_override_show(struct kobject *kobj,
 471                                    struct kobj_attribute *a, char *buf)
 472 {
 473         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 474         int quota_override;
 475
 476         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 477         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 478 }
 479
 480 static ssize_t quota_override_store(struct kobject *kobj,
 481                                     struct kobj_attribute *a,
 482                                     const char *buf, size_t len)
 483 {
 484         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 485         unsigned long knob;
 486         int err;
 487
 488         if (!fs_info)
 489                 return -EPERM;
 490
 491         if (!capable(CAP_SYS_RESOURCE))
 492                 return -EPERM;
 493
 494         err = kstrtoul(buf, 10, &knob);
 495         if (err)
 496                 return err;
 497         if (knob > 1)
 498                 return -EINVAL;
 499
 500         if (knob)
 501                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 502         else
 503                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 504
 505         return len;
 506 }
 507
 508 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 509
 510 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 511                                 struct kobj_attribute *a, char *buf)
 512 {
 513         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 514
 515         return snprintf(buf, PAGE_SIZE, "%pU\n",
 516                         fs_info->fs_devices->metadata_uuid);
 517 }
 518
 519 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 520
 521 static const struct attribute *btrfs_attrs[] = {
 522         BTRFS_ATTR_PTR(, label),
 523         BTRFS_ATTR_PTR(, nodesize),
 524         BTRFS_ATTR_PTR(, sectorsize),
 525         BTRFS_ATTR_PTR(, clone_alignment),
 526         BTRFS_ATTR_PTR(, quota_override),
 527         BTRFS_ATTR_PTR(, metadata_uuid),
 528         NULL,
 529 };
 530
 531 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 532 {
 533         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 534
 535         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 536         complete(&fs_devs->kobj_unregister);
 537 }
 538
 539 static struct kobj_type btrfs_ktype = {
 540         .sysfs_ops      = &kobj_sysfs_ops,
 541         .release        = btrfs_release_fsid_kobj,
 542 };
 543
 544 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 545 {
 546         if (kobj->ktype != &btrfs_ktype)
 547                 return NULL;
 548         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 549 }
 550
 551 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 552 {
 553         if (kobj->ktype != &btrfs_ktype)
 554                 return NULL;
 555         return to_fs_devs(kobj)->fs_info;
 556 }
 557
 558 #define NUM_FEATURE_BITS 64
 559 #define BTRFS_FEATURE_NAME_MAX 13
 560 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 561 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 562
 563 static const u64 supported_feature_masks[FEAT_MAX] = {
 564         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 565         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 566         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 567 };
 568
 569 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 570 {
 571         int set;
 572
 573         for (set = 0; set < FEAT_MAX; set++) {
 574                 int i;
 575                 struct attribute *attrs[2];
 576                 struct attribute_group agroup = {
 577                         .name = "features",
 578                         .attrs = attrs,
 579                 };
 580                 u64 features = get_features(fs_info, set);
 581                 features &= ~supported_feature_masks[set];
 582
 583                 if (!features)
 584                         continue;
 585
 586                 attrs[1] = NULL;
 587                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 588                         struct btrfs_feature_attr *fa;
 589
 590                         if (!(features & (1ULL << i)))
 591                                 continue;
 592
 593                         fa = &btrfs_feature_attrs[set][i];
 594                         attrs[0] = &fa->kobj_attr.attr;
 595                         if (add) {
 596                                 int ret;
 597                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 598                                                         &agroup);
 599                                 if (ret)
 600                                         return ret;
 601                         } else
 602                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 603                                                     &agroup);
 604                 }
 605
 606         }
 607         return 0;
 608 }
 609
 610 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 611 {
 612         if (fs_devs->device_dir_kobj) {
 613                 kobject_del(fs_devs->device_dir_kobj);
 614                 kobject_put(fs_devs->device_dir_kobj);
 615                 fs_devs->device_dir_kobj = NULL;
 616         }
 617
 618         if (fs_devs->fsid_kobj.state_initialized) {
 619                 kobject_del(&fs_devs->fsid_kobj);
 620                 kobject_put(&fs_devs->fsid_kobj);
 621                 wait_for_completion(&fs_devs->kobj_unregister);
 622         }
 623 }
 624
 625 /* when fs_devs is NULL it will remove all fsid kobject */
 626 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 627 {
 628         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 629
 630         if (fs_devs) {
 631                 __btrfs_sysfs_remove_fsid(fs_devs);
 632                 return;
 633         }
 634
 635         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 636                 __btrfs_sysfs_remove_fsid(fs_devs);
 637         }
 638 }
 639
 640 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 641 {
 642         btrfs_reset_fs_info_ptr(fs_info);
 643
 644         if (fs_info->space_info_kobj) {
 645                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 646                 kobject_del(fs_info->space_info_kobj);
 647                 kobject_put(fs_info->space_info_kobj);
 648         }
 649         addrm_unknown_feature_attrs(fs_info, false);
 650         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 651         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 652         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 653 }
 654
 655 const char * const btrfs_feature_set_names[FEAT_MAX] = {
 656         [FEAT_COMPAT]    = "compat",
 657         [FEAT_COMPAT_RO] = "compat_ro",
 658         [FEAT_INCOMPAT]  = "incompat",
 659 };
 660
 661 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 662 {
 663         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 664         int len = 0;
 665         int i;
 666         char *str;
 667
 668         str = kmalloc(bufsize, GFP_KERNEL);
 669         if (!str)
 670                 return str;
 671
 672         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 673                 const char *name;
 674
 675                 if (!(flags & (1ULL << i)))
 676                         continue;
 677
 678                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 679                 len += snprintf(str + len, bufsize - len, "%s%s",
 680                                 len ? "," : "", name);
 681         }
 682
 683         return str;
 684 }
 685
 686 static void init_feature_attrs(void)
 687 {
 688         struct btrfs_feature_attr *fa;
 689         int set, i;
 690
 691         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 692                      ARRAY_SIZE(btrfs_feature_attrs));
 693         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 694                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 695
 696         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 697         memset(btrfs_unknown_feature_names, 0,
 698                sizeof(btrfs_unknown_feature_names));
 699
 700         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 701                 struct btrfs_feature_attr *sfa;
 702                 struct attribute *a = btrfs_supported_feature_attrs[i];
 703                 int bit;
 704                 sfa = attr_to_btrfs_feature_attr(a);
 705                 bit = ilog2(sfa->feature_bit);
 706                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 707
 708                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 709         }
 710
 711         for (set = 0; set < FEAT_MAX; set++) {
 712                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 713                         char *name = btrfs_unknown_feature_names[set][i];
 714                         fa = &btrfs_feature_attrs[set][i];
 715
 716                         if (fa->kobj_attr.attr.name)
 717                                 continue;
 718
 719                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 720                                  btrfs_feature_set_names[set], i);
 721
 722                         fa->kobj_attr.attr.name = name;
 723                         fa->kobj_attr.attr.mode = S_IRUGO;
 724                         fa->feature_set = set;
 725                         fa->feature_bit = 1ULL << i;
 726                 }
 727         }
 728 }
 729
 730 /* when one_device is NULL, it removes all device links */
 731
 732 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 733                 struct btrfs_device *one_device)
 734 {
 735         struct hd_struct *disk;
 736         struct kobject *disk_kobj;
 737
 738         if (!fs_devices->device_dir_kobj)
 739                 return -EINVAL;
 740
 741         if (one_device && one_device->bdev) {
 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         if (one_device)
 750                 return 0;
 751
 752         list_for_each_entry(one_device,
 753                         &fs_devices->devices, dev_list) {
 754                 if (!one_device->bdev)
 755                         continue;
 756                 disk = one_device->bdev->bd_part;
 757                 disk_kobj = &part_to_dev(disk)->kobj;
 758
 759                 sysfs_remove_link(fs_devices->device_dir_kobj,
 760                                                 disk_kobj->name);
 761         }
 762
 763         return 0;
 764 }
 765
 766 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 767 {
 768         if (!fs_devs->device_dir_kobj)
 769                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 770                                                 &fs_devs->fsid_kobj);
 771
 772         if (!fs_devs->device_dir_kobj)
 773                 return -ENOMEM;
 774
 775         return 0;
 776 }
 777
 778 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 779                                 struct btrfs_device *one_device)
 780 {
 781         int error = 0;
 782         struct btrfs_device *dev;
 783
 784         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 785                 struct hd_struct *disk;
 786                 struct kobject *disk_kobj;
 787
 788                 if (!dev->bdev)
 789                         continue;
 790
 791                 if (one_device && one_device != dev)
 792                         continue;
 793
 794                 disk = dev->bdev->bd_part;
 795                 disk_kobj = &part_to_dev(disk)->kobj;
 796
 797                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 798                                           disk_kobj, disk_kobj->name);
 799                 if (error)
 800                         break;
 801         }
 802
 803         return error;
 804 }
 805
 806 /* /sys/fs/btrfs/ entry */
 807 static struct kset *btrfs_kset;
 808
 809 /* /sys/kernel/debug/btrfs */
 810 static struct dentry *btrfs_debugfs_root_dentry;
 811
 812 /* Debugging tunables and exported data */
 813 u64 btrfs_debugfs_test;
 814
 815 /*
 816  * Can be called by the device discovery thread.
 817  * And parent can be specified for seed device
 818  */
 819 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 820                                 struct kobject *parent)
 821 {
 822         int error;
 823
 824         init_completion(&fs_devs->kobj_unregister);
 825         fs_devs->fsid_kobj.kset = btrfs_kset;
 826         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 827                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 828         return error;
 829 }
 830
 831 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 832 {
 833         int error;
 834         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 835         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 836
 837         btrfs_set_fs_info_ptr(fs_info);
 838
 839         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 840         if (error)
 841                 return error;
 842
 843         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 844         if (error) {
 845                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 846                 return error;
 847         }
 848
 849         error = sysfs_create_group(fsid_kobj,
 850                                    &btrfs_feature_attr_group);
 851         if (error)
 852                 goto failure;
 853
 854         error = addrm_unknown_feature_attrs(fs_info, true);
 855         if (error)
 856                 goto failure;
 857
 858         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 859                                                   fsid_kobj);
 860         if (!fs_info->space_info_kobj) {
 861                 error = -ENOMEM;
 862                 goto failure;
 863         }
 864
 865         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 866         if (error)
 867                 goto failure;
 868
 869         return 0;
 870 failure:
 871         btrfs_sysfs_remove_mounted(fs_info);
 872         return error;
 873 }
 874
 875
 876 /*
 877  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 878  * values in superblock. Call after any changes to incompat/compat_ro flags
 879  */
 880 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 881                 u64 bit, enum btrfs_feature_set set)
 882 {
 883         struct btrfs_fs_devices *fs_devs;
 884         struct kobject *fsid_kobj;
 885         u64 features;
 886         int ret;
 887
 888         if (!fs_info)
 889                 return;
 890
 891         features = get_features(fs_info, set);
 892         ASSERT(bit & supported_feature_masks[set]);
 893
 894         fs_devs = fs_info->fs_devices;
 895         fsid_kobj = &fs_devs->fsid_kobj;
 896
 897         if (!fsid_kobj->state_initialized)
 898                 return;
 899
 900         /*
 901          * FIXME: this is too heavy to update just one value, ideally we'd like
 902          * to use sysfs_update_group but some refactoring is needed first.
 903          */
 904         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 905         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 906 }
 907
 908 static int btrfs_init_debugfs(void)
 909 {
 910 #ifdef CONFIG_DEBUG_FS
 911         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 912         if (!btrfs_debugfs_root_dentry)
 913                 return -ENOMEM;
 914
 915         /*
 916          * Example code, how to export data through debugfs.
 917          *
 918          * file:        /sys/kernel/debug/btrfs/test
 919          * contents of: btrfs_debugfs_test
 920          */
 921 #ifdef CONFIG_BTRFS_DEBUG
 922         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
 923                         &btrfs_debugfs_test);
 924 #endif
 925
 926 #endif
 927         return 0;
 928 }
 929
 930 int __init btrfs_init_sysfs(void)
 931 {
 932         int ret;
 933
 934         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 935         if (!btrfs_kset)
 936                 return -ENOMEM;
 937
 938         ret = btrfs_init_debugfs();
 939         if (ret)
 940                 goto out1;
 941
 942         init_feature_attrs();
 943         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 944         if (ret)
 945                 goto out2;
 946         ret = sysfs_merge_group(&btrfs_kset->kobj,
 947                                 &btrfs_static_feature_attr_group);
 948         if (ret)
 949                 goto out_remove_group;
 950
 951         return 0;
 952
 953 out_remove_group:
 954         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 955 out2:
 956         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 957 out1:
 958         kset_unregister(btrfs_kset);
 959
 960         return ret;
 961 }
 962
 963 void __cold btrfs_exit_sysfs(void)
 964 {
 965         sysfs_unmerge_group(&btrfs_kset->kobj,
 966                             &btrfs_static_feature_attr_group);
 967         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 968         kset_unregister(btrfs_kset);
 969         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 970 }
 971