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/buffer_head.h>
  11 #include <linux/kobject.h>
  12 #include <linux/bug.h>
  13 #include <linux/genhd.h>
  14 #include <linux/debugfs.h>
  15
  16 #include "ctree.h"
  17 #include "disk-io.h"
  18 #include "transaction.h"
  19 #include "sysfs.h"
  20 #include "volumes.h"
  21
  22 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  23 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
  24
  25 static u64 get_features(struct btrfs_fs_info *fs_info,
  26                         enum btrfs_feature_set set)
  27 {
  28         struct btrfs_super_block *disk_super = fs_info->super_copy;
  29         if (set == FEAT_COMPAT)
  30                 return btrfs_super_compat_flags(disk_super);
  31         else if (set == FEAT_COMPAT_RO)
  32                 return btrfs_super_compat_ro_flags(disk_super);
  33         else
  34                 return btrfs_super_incompat_flags(disk_super);
  35 }
  36
  37 static void set_features(struct btrfs_fs_info *fs_info,
  38                          enum btrfs_feature_set set, u64 features)
  39 {
  40         struct btrfs_super_block *disk_super = fs_info->super_copy;
  41         if (set == FEAT_COMPAT)
  42                 btrfs_set_super_compat_flags(disk_super, features);
  43         else if (set == FEAT_COMPAT_RO)
  44                 btrfs_set_super_compat_ro_flags(disk_super, features);
  45         else
  46                 btrfs_set_super_incompat_flags(disk_super, features);
  47 }
  48
  49 static int can_modify_feature(struct btrfs_feature_attr *fa)
  50 {
  51         int val = 0;
  52         u64 set, clear;
  53         switch (fa->feature_set) {
  54         case FEAT_COMPAT:
  55                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  56                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  57                 break;
  58         case FEAT_COMPAT_RO:
  59                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  60                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  61                 break;
  62         case FEAT_INCOMPAT:
  63                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  64                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  65                 break;
  66         default:
  67                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
  68                                 fa->feature_set);
  69                 return 0;
  70         }
  71
  72         if (set & fa->feature_bit)
  73                 val |= 1;
  74         if (clear & fa->feature_bit)
  75                 val |= 2;
  76
  77         return val;
  78 }
  79
  80 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  81                                        struct kobj_attribute *a, char *buf)
  82 {
  83         int val = 0;
  84         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  85         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
  86         if (fs_info) {
  87                 u64 features = get_features(fs_info, fa->feature_set);
  88                 if (features & fa->feature_bit)
  89                         val = 1;
  90         } else
  91                 val = can_modify_feature(fa);
  92
  93         return snprintf(buf, PAGE_SIZE, "%d\n", val);
  94 }
  95
  96 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
  97                                         struct kobj_attribute *a,
  98                                         const char *buf, size_t count)
  99 {
 100         struct btrfs_fs_info *fs_info;
 101         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 102         u64 features, set, clear;
 103         unsigned long val;
 104         int ret;
 105
 106         fs_info = to_fs_info(kobj);
 107         if (!fs_info)
 108                 return -EPERM;
 109
 110         if (sb_rdonly(fs_info->sb))
 111                 return -EROFS;
 112
 113         ret = kstrtoul(skip_spaces(buf), 0, &val);
 114         if (ret)
 115                 return ret;
 116
 117         if (fa->feature_set == FEAT_COMPAT) {
 118                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 119                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 120         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 121                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 122                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 123         } else {
 124                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 125                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 126         }
 127
 128         features = get_features(fs_info, fa->feature_set);
 129
 130         /* Nothing to do */
 131         if ((val && (features & fa->feature_bit)) ||
 132             (!val && !(features & fa->feature_bit)))
 133                 return count;
 134
 135         if ((val && !(set & fa->feature_bit)) ||
 136             (!val && !(clear & fa->feature_bit))) {
 137                 btrfs_info(fs_info,
 138                         "%sabling feature %s on mounted fs is not supported.",
 139                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 140                 return -EPERM;
 141         }
 142
 143         btrfs_info(fs_info, "%s %s feature flag",
 144                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 145
 146         spin_lock(&fs_info->super_lock);
 147         features = get_features(fs_info, fa->feature_set);
 148         if (val)
 149                 features |= fa->feature_bit;
 150         else
 151                 features &= ~fa->feature_bit;
 152         set_features(fs_info, fa->feature_set, features);
 153         spin_unlock(&fs_info->super_lock);
 154
 155         /*
 156          * We don't want to do full transaction commit from inside sysfs
 157          */
 158         btrfs_set_pending(fs_info, COMMIT);
 159         wake_up_process(fs_info->transaction_kthread);
 160
 161         return count;
 162 }
 163
 164 static umode_t btrfs_feature_visible(struct kobject *kobj,
 165                                      struct attribute *attr, int unused)
 166 {
 167         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 168         umode_t mode = attr->mode;
 169
 170         if (fs_info) {
 171                 struct btrfs_feature_attr *fa;
 172                 u64 features;
 173
 174                 fa = attr_to_btrfs_feature_attr(attr);
 175                 features = get_features(fs_info, fa->feature_set);
 176
 177                 if (can_modify_feature(fa))
 178                         mode |= S_IWUSR;
 179                 else if (!(features & fa->feature_bit))
 180                         mode = 0;
 181         }
 182
 183         return mode;
 184 }
 185
 186 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 187 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 188 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 189 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 190 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
 191 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 192 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 193 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 194 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 195 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 196 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 197
 198 static struct attribute *btrfs_supported_feature_attrs[] = {
 199         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 200         BTRFS_FEAT_ATTR_PTR(default_subvol),
 201         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 202         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 203         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 204         BTRFS_FEAT_ATTR_PTR(big_metadata),
 205         BTRFS_FEAT_ATTR_PTR(extended_iref),
 206         BTRFS_FEAT_ATTR_PTR(raid56),
 207         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 208         BTRFS_FEAT_ATTR_PTR(no_holes),
 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 const struct attribute *btrfs_attrs[] = {
 511         BTRFS_ATTR_PTR(, label),
 512         BTRFS_ATTR_PTR(, nodesize),
 513         BTRFS_ATTR_PTR(, sectorsize),
 514         BTRFS_ATTR_PTR(, clone_alignment),
 515         BTRFS_ATTR_PTR(, quota_override),
 516         NULL,
 517 };
 518
 519 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 520 {
 521         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 522
 523         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 524         complete(&fs_devs->kobj_unregister);
 525 }
 526
 527 static struct kobj_type btrfs_ktype = {
 528         .sysfs_ops      = &kobj_sysfs_ops,
 529         .release        = btrfs_release_fsid_kobj,
 530 };
 531
 532 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 533 {
 534         if (kobj->ktype != &btrfs_ktype)
 535                 return NULL;
 536         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 537 }
 538
 539 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 540 {
 541         if (kobj->ktype != &btrfs_ktype)
 542                 return NULL;
 543         return to_fs_devs(kobj)->fs_info;
 544 }
 545
 546 #define NUM_FEATURE_BITS 64
 547 #define BTRFS_FEATURE_NAME_MAX 13
 548 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 549 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 550
 551 static const u64 supported_feature_masks[FEAT_MAX] = {
 552         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 553         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 554         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 555 };
 556
 557 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 558 {
 559         int set;
 560
 561         for (set = 0; set < FEAT_MAX; set++) {
 562                 int i;
 563                 struct attribute *attrs[2];
 564                 struct attribute_group agroup = {
 565                         .name = "features",
 566                         .attrs = attrs,
 567                 };
 568                 u64 features = get_features(fs_info, set);
 569                 features &= ~supported_feature_masks[set];
 570
 571                 if (!features)
 572                         continue;
 573
 574                 attrs[1] = NULL;
 575                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 576                         struct btrfs_feature_attr *fa;
 577
 578                         if (!(features & (1ULL << i)))
 579                                 continue;
 580
 581                         fa = &btrfs_feature_attrs[set][i];
 582                         attrs[0] = &fa->kobj_attr.attr;
 583                         if (add) {
 584                                 int ret;
 585                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 586                                                         &agroup);
 587                                 if (ret)
 588                                         return ret;
 589                         } else
 590                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 591                                                     &agroup);
 592                 }
 593
 594         }
 595         return 0;
 596 }
 597
 598 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 599 {
 600         if (fs_devs->device_dir_kobj) {
 601                 kobject_del(fs_devs->device_dir_kobj);
 602                 kobject_put(fs_devs->device_dir_kobj);
 603                 fs_devs->device_dir_kobj = NULL;
 604         }
 605
 606         if (fs_devs->fsid_kobj.state_initialized) {
 607                 kobject_del(&fs_devs->fsid_kobj);
 608                 kobject_put(&fs_devs->fsid_kobj);
 609                 wait_for_completion(&fs_devs->kobj_unregister);
 610         }
 611 }
 612
 613 /* when fs_devs is NULL it will remove all fsid kobject */
 614 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 615 {
 616         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 617
 618         if (fs_devs) {
 619                 __btrfs_sysfs_remove_fsid(fs_devs);
 620                 return;
 621         }
 622
 623         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 624                 __btrfs_sysfs_remove_fsid(fs_devs);
 625         }
 626 }
 627
 628 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 629 {
 630         btrfs_reset_fs_info_ptr(fs_info);
 631
 632         if (fs_info->space_info_kobj) {
 633                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 634                 kobject_del(fs_info->space_info_kobj);
 635                 kobject_put(fs_info->space_info_kobj);
 636         }
 637         addrm_unknown_feature_attrs(fs_info, false);
 638         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 639         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 640         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 641 }
 642
 643 const char * const btrfs_feature_set_names[FEAT_MAX] = {
 644         [FEAT_COMPAT]    = "compat",
 645         [FEAT_COMPAT_RO] = "compat_ro",
 646         [FEAT_INCOMPAT]  = "incompat",
 647 };
 648
 649 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 650 {
 651         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 652         int len = 0;
 653         int i;
 654         char *str;
 655
 656         str = kmalloc(bufsize, GFP_KERNEL);
 657         if (!str)
 658                 return str;
 659
 660         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 661                 const char *name;
 662
 663                 if (!(flags & (1ULL << i)))
 664                         continue;
 665
 666                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 667                 len += snprintf(str + len, bufsize - len, "%s%s",
 668                                 len ? "," : "", name);
 669         }
 670
 671         return str;
 672 }
 673
 674 static void init_feature_attrs(void)
 675 {
 676         struct btrfs_feature_attr *fa;
 677         int set, i;
 678
 679         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 680                      ARRAY_SIZE(btrfs_feature_attrs));
 681         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 682                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 683
 684         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 685         memset(btrfs_unknown_feature_names, 0,
 686                sizeof(btrfs_unknown_feature_names));
 687
 688         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 689                 struct btrfs_feature_attr *sfa;
 690                 struct attribute *a = btrfs_supported_feature_attrs[i];
 691                 int bit;
 692                 sfa = attr_to_btrfs_feature_attr(a);
 693                 bit = ilog2(sfa->feature_bit);
 694                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 695
 696                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 697         }
 698
 699         for (set = 0; set < FEAT_MAX; set++) {
 700                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 701                         char *name = btrfs_unknown_feature_names[set][i];
 702                         fa = &btrfs_feature_attrs[set][i];
 703
 704                         if (fa->kobj_attr.attr.name)
 705                                 continue;
 706
 707                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 708                                  btrfs_feature_set_names[set], i);
 709
 710                         fa->kobj_attr.attr.name = name;
 711                         fa->kobj_attr.attr.mode = S_IRUGO;
 712                         fa->feature_set = set;
 713                         fa->feature_bit = 1ULL << i;
 714                 }
 715         }
 716 }
 717
 718 /* when one_device is NULL, it removes all device links */
 719
 720 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 721                 struct btrfs_device *one_device)
 722 {
 723         struct hd_struct *disk;
 724         struct kobject *disk_kobj;
 725
 726         if (!fs_devices->device_dir_kobj)
 727                 return -EINVAL;
 728
 729         if (one_device && one_device->bdev) {
 730                 disk = one_device->bdev->bd_part;
 731                 disk_kobj = &part_to_dev(disk)->kobj;
 732
 733                 sysfs_remove_link(fs_devices->device_dir_kobj,
 734                                                 disk_kobj->name);
 735         }
 736
 737         if (one_device)
 738                 return 0;
 739
 740         list_for_each_entry(one_device,
 741                         &fs_devices->devices, dev_list) {
 742                 if (!one_device->bdev)
 743                         continue;
 744                 disk = one_device->bdev->bd_part;
 745                 disk_kobj = &part_to_dev(disk)->kobj;
 746
 747                 sysfs_remove_link(fs_devices->device_dir_kobj,
 748                                                 disk_kobj->name);
 749         }
 750
 751         return 0;
 752 }
 753
 754 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 755 {
 756         if (!fs_devs->device_dir_kobj)
 757                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 758                                                 &fs_devs->fsid_kobj);
 759
 760         if (!fs_devs->device_dir_kobj)
 761                 return -ENOMEM;
 762
 763         return 0;
 764 }
 765
 766 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 767                                 struct btrfs_device *one_device)
 768 {
 769         int error = 0;
 770         struct btrfs_device *dev;
 771
 772         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 773                 struct hd_struct *disk;
 774                 struct kobject *disk_kobj;
 775
 776                 if (!dev->bdev)
 777                         continue;
 778
 779                 if (one_device && one_device != dev)
 780                         continue;
 781
 782                 disk = dev->bdev->bd_part;
 783                 disk_kobj = &part_to_dev(disk)->kobj;
 784
 785                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 786                                           disk_kobj, disk_kobj->name);
 787                 if (error)
 788                         break;
 789         }
 790
 791         return error;
 792 }
 793
 794 /* /sys/fs/btrfs/ entry */
 795 static struct kset *btrfs_kset;
 796
 797 /* /sys/kernel/debug/btrfs */
 798 static struct dentry *btrfs_debugfs_root_dentry;
 799
 800 /* Debugging tunables and exported data */
 801 u64 btrfs_debugfs_test;
 802
 803 /*
 804  * Can be called by the device discovery thread.
 805  * And parent can be specified for seed device
 806  */
 807 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 808                                 struct kobject *parent)
 809 {
 810         int error;
 811
 812         init_completion(&fs_devs->kobj_unregister);
 813         fs_devs->fsid_kobj.kset = btrfs_kset;
 814         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 815                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 816         return error;
 817 }
 818
 819 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 820 {
 821         int error;
 822         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 823         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 824
 825         btrfs_set_fs_info_ptr(fs_info);
 826
 827         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 828         if (error)
 829                 return error;
 830
 831         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 832         if (error) {
 833                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 834                 return error;
 835         }
 836
 837         error = sysfs_create_group(fsid_kobj,
 838                                    &btrfs_feature_attr_group);
 839         if (error)
 840                 goto failure;
 841
 842         error = addrm_unknown_feature_attrs(fs_info, true);
 843         if (error)
 844                 goto failure;
 845
 846         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 847                                                   fsid_kobj);
 848         if (!fs_info->space_info_kobj) {
 849                 error = -ENOMEM;
 850                 goto failure;
 851         }
 852
 853         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 854         if (error)
 855                 goto failure;
 856
 857         return 0;
 858 failure:
 859         btrfs_sysfs_remove_mounted(fs_info);
 860         return error;
 861 }
 862
 863
 864 /*
 865  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 866  * values in superblock. Call after any changes to incompat/compat_ro flags
 867  */
 868 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 869                 u64 bit, enum btrfs_feature_set set)
 870 {
 871         struct btrfs_fs_devices *fs_devs;
 872         struct kobject *fsid_kobj;
 873         u64 features;
 874         int ret;
 875
 876         if (!fs_info)
 877                 return;
 878
 879         features = get_features(fs_info, set);
 880         ASSERT(bit & supported_feature_masks[set]);
 881
 882         fs_devs = fs_info->fs_devices;
 883         fsid_kobj = &fs_devs->fsid_kobj;
 884
 885         if (!fsid_kobj->state_initialized)
 886                 return;
 887
 888         /*
 889          * FIXME: this is too heavy to update just one value, ideally we'd like
 890          * to use sysfs_update_group but some refactoring is needed first.
 891          */
 892         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 893         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 894 }
 895
 896 static int btrfs_init_debugfs(void)
 897 {
 898 #ifdef CONFIG_DEBUG_FS
 899         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 900         if (!btrfs_debugfs_root_dentry)
 901                 return -ENOMEM;
 902
 903         /*
 904          * Example code, how to export data through debugfs.
 905          *
 906          * file:        /sys/kernel/debug/btrfs/test
 907          * contents of: btrfs_debugfs_test
 908          */
 909 #ifdef CONFIG_BTRFS_DEBUG
 910         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
 911                         &btrfs_debugfs_test);
 912 #endif
 913
 914 #endif
 915         return 0;
 916 }
 917
 918 int __init btrfs_init_sysfs(void)
 919 {
 920         int ret;
 921
 922         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 923         if (!btrfs_kset)
 924                 return -ENOMEM;
 925
 926         ret = btrfs_init_debugfs();
 927         if (ret)
 928                 goto out1;
 929
 930         init_feature_attrs();
 931         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 932         if (ret)
 933                 goto out2;
 934         ret = sysfs_merge_group(&btrfs_kset->kobj,
 935                                 &btrfs_static_feature_attr_group);
 936         if (ret)
 937                 goto out_remove_group;
 938
 939         return 0;
 940
 941 out_remove_group:
 942         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 943 out2:
 944         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 945 out1:
 946         kset_unregister(btrfs_kset);
 947
 948         return ret;
 949 }
 950
 951 void __cold btrfs_exit_sysfs(void)
 952 {
 953         sysfs_unmerge_group(&btrfs_kset->kobj,
 954                             &btrfs_static_feature_attr_group);
 955         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 956         kset_unregister(btrfs_kset);
 957         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 958 }
 959