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 static const struct attribute_group btrfs_feature_attr_group = {
 214         .name = "features",
 215         .is_visible = btrfs_feature_visible,
 216         .attrs = btrfs_supported_feature_attrs,
 217 };
 218
 219 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 220 {
 221         u64 val;
 222         if (lock)
 223                 spin_lock(lock);
 224         val = *value_ptr;
 225         if (lock)
 226                 spin_unlock(lock);
 227         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 228 }
 229
 230 static ssize_t global_rsv_size_show(struct kobject *kobj,
 231                                     struct kobj_attribute *ka, char *buf)
 232 {
 233         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 234         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 235         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 236 }
 237 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 238
 239 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 240                                         struct kobj_attribute *a, char *buf)
 241 {
 242         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 243         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 244         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 245 }
 246 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 247
 248 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 249 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 250
 251 static ssize_t raid_bytes_show(struct kobject *kobj,
 252                                struct kobj_attribute *attr, char *buf);
 253 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 254 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 255
 256 static ssize_t raid_bytes_show(struct kobject *kobj,
 257                                struct kobj_attribute *attr, char *buf)
 258
 259 {
 260         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 261         struct btrfs_block_group_cache *block_group;
 262         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 263         u64 val = 0;
 264
 265         down_read(&sinfo->groups_sem);
 266         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 267                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 268                         val += block_group->key.offset;
 269                 else
 270                         val += btrfs_block_group_used(&block_group->item);
 271         }
 272         up_read(&sinfo->groups_sem);
 273         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 274 }
 275
 276 static struct attribute *raid_attributes[] = {
 277         BTRFS_ATTR_PTR(raid, total_bytes),
 278         BTRFS_ATTR_PTR(raid, used_bytes),
 279         NULL
 280 };
 281
 282 static void release_raid_kobj(struct kobject *kobj)
 283 {
 284         kfree(to_raid_kobj(kobj));
 285 }
 286
 287 struct kobj_type btrfs_raid_ktype = {
 288         .sysfs_ops = &kobj_sysfs_ops,
 289         .release = release_raid_kobj,
 290         .default_attrs = raid_attributes,
 291 };
 292
 293 #define SPACE_INFO_ATTR(field)                                          \
 294 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 295                                              struct kobj_attribute *a,  \
 296                                              char *buf)                 \
 297 {                                                                       \
 298         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 299         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 300 }                                                                       \
 301 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 302
 303 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 304                                                        struct kobj_attribute *a,
 305                                                        char *buf)
 306 {
 307         struct btrfs_space_info *sinfo = to_space_info(kobj);
 308         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 309         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 310 }
 311
 312 SPACE_INFO_ATTR(flags);
 313 SPACE_INFO_ATTR(total_bytes);
 314 SPACE_INFO_ATTR(bytes_used);
 315 SPACE_INFO_ATTR(bytes_pinned);
 316 SPACE_INFO_ATTR(bytes_reserved);
 317 SPACE_INFO_ATTR(bytes_may_use);
 318 SPACE_INFO_ATTR(bytes_readonly);
 319 SPACE_INFO_ATTR(disk_used);
 320 SPACE_INFO_ATTR(disk_total);
 321 BTRFS_ATTR(space_info, total_bytes_pinned,
 322            btrfs_space_info_show_total_bytes_pinned);
 323
 324 static struct attribute *space_info_attrs[] = {
 325         BTRFS_ATTR_PTR(space_info, flags),
 326         BTRFS_ATTR_PTR(space_info, total_bytes),
 327         BTRFS_ATTR_PTR(space_info, bytes_used),
 328         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 329         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 330         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 331         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 332         BTRFS_ATTR_PTR(space_info, disk_used),
 333         BTRFS_ATTR_PTR(space_info, disk_total),
 334         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 335         NULL,
 336 };
 337
 338 static void space_info_release(struct kobject *kobj)
 339 {
 340         struct btrfs_space_info *sinfo = to_space_info(kobj);
 341         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 342         kfree(sinfo);
 343 }
 344
 345 struct kobj_type space_info_ktype = {
 346         .sysfs_ops = &kobj_sysfs_ops,
 347         .release = space_info_release,
 348         .default_attrs = space_info_attrs,
 349 };
 350
 351 static const struct attribute *allocation_attrs[] = {
 352         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 353         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 354         NULL,
 355 };
 356
 357 static ssize_t btrfs_label_show(struct kobject *kobj,
 358                                 struct kobj_attribute *a, char *buf)
 359 {
 360         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 361         char *label = fs_info->super_copy->label;
 362         ssize_t ret;
 363
 364         spin_lock(&fs_info->super_lock);
 365         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 366         spin_unlock(&fs_info->super_lock);
 367
 368         return ret;
 369 }
 370
 371 static ssize_t btrfs_label_store(struct kobject *kobj,
 372                                  struct kobj_attribute *a,
 373                                  const char *buf, size_t len)
 374 {
 375         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 376         size_t p_len;
 377
 378         if (!fs_info)
 379                 return -EPERM;
 380
 381         if (sb_rdonly(fs_info->sb))
 382                 return -EROFS;
 383
 384         /*
 385          * p_len is the len until the first occurrence of either
 386          * '\n' or '\0'
 387          */
 388         p_len = strcspn(buf, "\n");
 389
 390         if (p_len >= BTRFS_LABEL_SIZE)
 391                 return -EINVAL;
 392
 393         spin_lock(&fs_info->super_lock);
 394         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 395         memcpy(fs_info->super_copy->label, buf, p_len);
 396         spin_unlock(&fs_info->super_lock);
 397
 398         /*
 399          * We don't want to do full transaction commit from inside sysfs
 400          */
 401         btrfs_set_pending(fs_info, COMMIT);
 402         wake_up_process(fs_info->transaction_kthread);
 403
 404         return len;
 405 }
 406 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 407
 408 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 409                                 struct kobj_attribute *a, char *buf)
 410 {
 411         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 412
 413         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 414 }
 415
 416 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 417
 418 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 419                                 struct kobj_attribute *a, char *buf)
 420 {
 421         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 422
 423         return snprintf(buf, PAGE_SIZE, "%u\n",
 424                         fs_info->super_copy->sectorsize);
 425 }
 426
 427 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 428
 429 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 430                                 struct kobj_attribute *a, char *buf)
 431 {
 432         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 433
 434         return snprintf(buf, PAGE_SIZE, "%u\n",
 435                         fs_info->super_copy->sectorsize);
 436 }
 437
 438 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 439
 440 static ssize_t quota_override_show(struct kobject *kobj,
 441                                    struct kobj_attribute *a, char *buf)
 442 {
 443         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 444         int quota_override;
 445
 446         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 447         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 448 }
 449
 450 static ssize_t quota_override_store(struct kobject *kobj,
 451                                     struct kobj_attribute *a,
 452                                     const char *buf, size_t len)
 453 {
 454         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 455         unsigned long knob;
 456         int err;
 457
 458         if (!fs_info)
 459                 return -EPERM;
 460
 461         if (!capable(CAP_SYS_RESOURCE))
 462                 return -EPERM;
 463
 464         err = kstrtoul(buf, 10, &knob);
 465         if (err)
 466                 return err;
 467         if (knob > 1)
 468                 return -EINVAL;
 469
 470         if (knob)
 471                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 472         else
 473                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 474
 475         return len;
 476 }
 477
 478 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 479
 480 static const struct attribute *btrfs_attrs[] = {
 481         BTRFS_ATTR_PTR(, label),
 482         BTRFS_ATTR_PTR(, nodesize),
 483         BTRFS_ATTR_PTR(, sectorsize),
 484         BTRFS_ATTR_PTR(, clone_alignment),
 485         BTRFS_ATTR_PTR(, quota_override),
 486         NULL,
 487 };
 488
 489 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 490 {
 491         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 492
 493         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 494         complete(&fs_devs->kobj_unregister);
 495 }
 496
 497 static struct kobj_type btrfs_ktype = {
 498         .sysfs_ops      = &kobj_sysfs_ops,
 499         .release        = btrfs_release_fsid_kobj,
 500 };
 501
 502 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 503 {
 504         if (kobj->ktype != &btrfs_ktype)
 505                 return NULL;
 506         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 507 }
 508
 509 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 510 {
 511         if (kobj->ktype != &btrfs_ktype)
 512                 return NULL;
 513         return to_fs_devs(kobj)->fs_info;
 514 }
 515
 516 #define NUM_FEATURE_BITS 64
 517 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 518 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 519
 520 static const u64 supported_feature_masks[3] = {
 521         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 522         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 523         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 524 };
 525
 526 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 527 {
 528         int set;
 529
 530         for (set = 0; set < FEAT_MAX; set++) {
 531                 int i;
 532                 struct attribute *attrs[2];
 533                 struct attribute_group agroup = {
 534                         .name = "features",
 535                         .attrs = attrs,
 536                 };
 537                 u64 features = get_features(fs_info, set);
 538                 features &= ~supported_feature_masks[set];
 539
 540                 if (!features)
 541                         continue;
 542
 543                 attrs[1] = NULL;
 544                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 545                         struct btrfs_feature_attr *fa;
 546
 547                         if (!(features & (1ULL << i)))
 548                                 continue;
 549
 550                         fa = &btrfs_feature_attrs[set][i];
 551                         attrs[0] = &fa->kobj_attr.attr;
 552                         if (add) {
 553                                 int ret;
 554                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 555                                                         &agroup);
 556                                 if (ret)
 557                                         return ret;
 558                         } else
 559                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 560                                                     &agroup);
 561                 }
 562
 563         }
 564         return 0;
 565 }
 566
 567 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 568 {
 569         if (fs_devs->device_dir_kobj) {
 570                 kobject_del(fs_devs->device_dir_kobj);
 571                 kobject_put(fs_devs->device_dir_kobj);
 572                 fs_devs->device_dir_kobj = NULL;
 573         }
 574
 575         if (fs_devs->fsid_kobj.state_initialized) {
 576                 kobject_del(&fs_devs->fsid_kobj);
 577                 kobject_put(&fs_devs->fsid_kobj);
 578                 wait_for_completion(&fs_devs->kobj_unregister);
 579         }
 580 }
 581
 582 /* when fs_devs is NULL it will remove all fsid kobject */
 583 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 584 {
 585         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 586
 587         if (fs_devs) {
 588                 __btrfs_sysfs_remove_fsid(fs_devs);
 589                 return;
 590         }
 591
 592         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 593                 __btrfs_sysfs_remove_fsid(fs_devs);
 594         }
 595 }
 596
 597 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 598 {
 599         btrfs_reset_fs_info_ptr(fs_info);
 600
 601         if (fs_info->space_info_kobj) {
 602                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 603                 kobject_del(fs_info->space_info_kobj);
 604                 kobject_put(fs_info->space_info_kobj);
 605         }
 606         addrm_unknown_feature_attrs(fs_info, false);
 607         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 608         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 609         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 610 }
 611
 612 const char * const btrfs_feature_set_names[3] = {
 613         [FEAT_COMPAT]    = "compat",
 614         [FEAT_COMPAT_RO] = "compat_ro",
 615         [FEAT_INCOMPAT]  = "incompat",
 616 };
 617
 618 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 619 {
 620         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 621         int len = 0;
 622         int i;
 623         char *str;
 624
 625         str = kmalloc(bufsize, GFP_KERNEL);
 626         if (!str)
 627                 return str;
 628
 629         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 630                 const char *name;
 631
 632                 if (!(flags & (1ULL << i)))
 633                         continue;
 634
 635                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 636                 len += snprintf(str + len, bufsize - len, "%s%s",
 637                                 len ? "," : "", name);
 638         }
 639
 640         return str;
 641 }
 642
 643 static void init_feature_attrs(void)
 644 {
 645         struct btrfs_feature_attr *fa;
 646         int set, i;
 647
 648         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 649                      ARRAY_SIZE(btrfs_feature_attrs));
 650         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 651                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 652
 653         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 654         memset(btrfs_unknown_feature_names, 0,
 655                sizeof(btrfs_unknown_feature_names));
 656
 657         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 658                 struct btrfs_feature_attr *sfa;
 659                 struct attribute *a = btrfs_supported_feature_attrs[i];
 660                 int bit;
 661                 sfa = attr_to_btrfs_feature_attr(a);
 662                 bit = ilog2(sfa->feature_bit);
 663                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 664
 665                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 666         }
 667
 668         for (set = 0; set < FEAT_MAX; set++) {
 669                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 670                         char *name = btrfs_unknown_feature_names[set][i];
 671                         fa = &btrfs_feature_attrs[set][i];
 672
 673                         if (fa->kobj_attr.attr.name)
 674                                 continue;
 675
 676                         snprintf(name, 13, "%s:%u",
 677                                  btrfs_feature_set_names[set], i);
 678
 679                         fa->kobj_attr.attr.name = name;
 680                         fa->kobj_attr.attr.mode = S_IRUGO;
 681                         fa->feature_set = set;
 682                         fa->feature_bit = 1ULL << i;
 683                 }
 684         }
 685 }
 686
 687 /* when one_device is NULL, it removes all device links */
 688
 689 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 690                 struct btrfs_device *one_device)
 691 {
 692         struct hd_struct *disk;
 693         struct kobject *disk_kobj;
 694
 695         if (!fs_devices->device_dir_kobj)
 696                 return -EINVAL;
 697
 698         if (one_device && one_device->bdev) {
 699                 disk = one_device->bdev->bd_part;
 700                 disk_kobj = &part_to_dev(disk)->kobj;
 701
 702                 sysfs_remove_link(fs_devices->device_dir_kobj,
 703                                                 disk_kobj->name);
 704         }
 705
 706         if (one_device)
 707                 return 0;
 708
 709         list_for_each_entry(one_device,
 710                         &fs_devices->devices, dev_list) {
 711                 if (!one_device->bdev)
 712                         continue;
 713                 disk = one_device->bdev->bd_part;
 714                 disk_kobj = &part_to_dev(disk)->kobj;
 715
 716                 sysfs_remove_link(fs_devices->device_dir_kobj,
 717                                                 disk_kobj->name);
 718         }
 719
 720         return 0;
 721 }
 722
 723 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 724 {
 725         if (!fs_devs->device_dir_kobj)
 726                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 727                                                 &fs_devs->fsid_kobj);
 728
 729         if (!fs_devs->device_dir_kobj)
 730                 return -ENOMEM;
 731
 732         return 0;
 733 }
 734
 735 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 736                                 struct btrfs_device *one_device)
 737 {
 738         int error = 0;
 739         struct btrfs_device *dev;
 740
 741         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 742                 struct hd_struct *disk;
 743                 struct kobject *disk_kobj;
 744
 745                 if (!dev->bdev)
 746                         continue;
 747
 748                 if (one_device && one_device != dev)
 749                         continue;
 750
 751                 disk = dev->bdev->bd_part;
 752                 disk_kobj = &part_to_dev(disk)->kobj;
 753
 754                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 755                                           disk_kobj, disk_kobj->name);
 756                 if (error)
 757                         break;
 758         }
 759
 760         return error;
 761 }
 762
 763 /* /sys/fs/btrfs/ entry */
 764 static struct kset *btrfs_kset;
 765
 766 /* /sys/kernel/debug/btrfs */
 767 static struct dentry *btrfs_debugfs_root_dentry;
 768
 769 /* Debugging tunables and exported data */
 770 u64 btrfs_debugfs_test;
 771
 772 /*
 773  * Can be called by the device discovery thread.
 774  * And parent can be specified for seed device
 775  */
 776 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 777                                 struct kobject *parent)
 778 {
 779         int error;
 780
 781         init_completion(&fs_devs->kobj_unregister);
 782         fs_devs->fsid_kobj.kset = btrfs_kset;
 783         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 784                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 785         return error;
 786 }
 787
 788 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 789 {
 790         int error;
 791         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 792         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 793
 794         btrfs_set_fs_info_ptr(fs_info);
 795
 796         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 797         if (error)
 798                 return error;
 799
 800         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 801         if (error) {
 802                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 803                 return error;
 804         }
 805
 806         error = sysfs_create_group(fsid_kobj,
 807                                    &btrfs_feature_attr_group);
 808         if (error)
 809                 goto failure;
 810
 811         error = addrm_unknown_feature_attrs(fs_info, true);
 812         if (error)
 813                 goto failure;
 814
 815         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 816                                                   fsid_kobj);
 817         if (!fs_info->space_info_kobj) {
 818                 error = -ENOMEM;
 819                 goto failure;
 820         }
 821
 822         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 823         if (error)
 824                 goto failure;
 825
 826         return 0;
 827 failure:
 828         btrfs_sysfs_remove_mounted(fs_info);
 829         return error;
 830 }
 831
 832
 833 /*
 834  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 835  * values in superblock. Call after any changes to incompat/compat_ro flags
 836  */
 837 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 838                 u64 bit, enum btrfs_feature_set set)
 839 {
 840         struct btrfs_fs_devices *fs_devs;
 841         struct kobject *fsid_kobj;
 842         u64 features;
 843         int ret;
 844
 845         if (!fs_info)
 846                 return;
 847
 848         features = get_features(fs_info, set);
 849         ASSERT(bit & supported_feature_masks[set]);
 850
 851         fs_devs = fs_info->fs_devices;
 852         fsid_kobj = &fs_devs->fsid_kobj;
 853
 854         if (!fsid_kobj->state_initialized)
 855                 return;
 856
 857         /*
 858          * FIXME: this is too heavy to update just one value, ideally we'd like
 859          * to use sysfs_update_group but some refactoring is needed first.
 860          */
 861         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 862         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 863 }
 864
 865 static int btrfs_init_debugfs(void)
 866 {
 867 #ifdef CONFIG_DEBUG_FS
 868         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 869         if (!btrfs_debugfs_root_dentry)
 870                 return -ENOMEM;
 871
 872         /*
 873          * Example code, how to export data through debugfs.
 874          *
 875          * file:        /sys/kernel/debug/btrfs/test
 876          * contents of: btrfs_debugfs_test
 877          */
 878 #ifdef CONFIG_BTRFS_DEBUG
 879         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
 880                         &btrfs_debugfs_test);
 881 #endif
 882
 883 #endif
 884         return 0;
 885 }
 886
 887 int __init btrfs_init_sysfs(void)
 888 {
 889         int ret;
 890
 891         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 892         if (!btrfs_kset)
 893                 return -ENOMEM;
 894
 895         ret = btrfs_init_debugfs();
 896         if (ret)
 897                 goto out1;
 898
 899         init_feature_attrs();
 900         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 901         if (ret)
 902                 goto out2;
 903
 904         return 0;
 905 out2:
 906         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 907 out1:
 908         kset_unregister(btrfs_kset);
 909
 910         return ret;
 911 }
 912
 913 void __cold btrfs_exit_sysfs(void)
 914 {
 915         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 916         kset_unregister(btrfs_kset);
 917         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 918 }
 919