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_attrs[] = {
 307         BTRFS_ATTR_PTR(raid, total_bytes),
 308         BTRFS_ATTR_PTR(raid, used_bytes),
 309         NULL
 310 };
 311 ATTRIBUTE_GROUPS(raid);
 312
 313 static void release_raid_kobj(struct kobject *kobj)
 314 {
 315         kfree(to_raid_kobj(kobj));
 316 }
 317
 318 struct kobj_type btrfs_raid_ktype = {
 319         .sysfs_ops = &kobj_sysfs_ops,
 320         .release = release_raid_kobj,
 321         .default_groups = raid_groups,
 322 };
 323
 324 #define SPACE_INFO_ATTR(field)                                          \
 325 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 326                                              struct kobj_attribute *a,  \
 327                                              char *buf)                 \
 328 {                                                                       \
 329         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 330         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 331 }                                                                       \
 332 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 333
 334 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 335                                                        struct kobj_attribute *a,
 336                                                        char *buf)
 337 {
 338         struct btrfs_space_info *sinfo = to_space_info(kobj);
 339         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 340         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 341 }
 342
 343 SPACE_INFO_ATTR(flags);
 344 SPACE_INFO_ATTR(total_bytes);
 345 SPACE_INFO_ATTR(bytes_used);
 346 SPACE_INFO_ATTR(bytes_pinned);
 347 SPACE_INFO_ATTR(bytes_reserved);
 348 SPACE_INFO_ATTR(bytes_may_use);
 349 SPACE_INFO_ATTR(bytes_readonly);
 350 SPACE_INFO_ATTR(disk_used);
 351 SPACE_INFO_ATTR(disk_total);
 352 BTRFS_ATTR(space_info, total_bytes_pinned,
 353            btrfs_space_info_show_total_bytes_pinned);
 354
 355 static struct attribute *space_info_attrs[] = {
 356         BTRFS_ATTR_PTR(space_info, flags),
 357         BTRFS_ATTR_PTR(space_info, total_bytes),
 358         BTRFS_ATTR_PTR(space_info, bytes_used),
 359         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 360         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 361         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 362         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 363         BTRFS_ATTR_PTR(space_info, disk_used),
 364         BTRFS_ATTR_PTR(space_info, disk_total),
 365         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 366         NULL,
 367 };
 368 ATTRIBUTE_GROUPS(space_info);
 369
 370 static void space_info_release(struct kobject *kobj)
 371 {
 372         struct btrfs_space_info *sinfo = to_space_info(kobj);
 373         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 374         kfree(sinfo);
 375 }
 376
 377 struct kobj_type space_info_ktype = {
 378         .sysfs_ops = &kobj_sysfs_ops,
 379         .release = space_info_release,
 380         .default_groups = space_info_groups,
 381 };
 382
 383 static const struct attribute *allocation_attrs[] = {
 384         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 385         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 386         NULL,
 387 };
 388
 389 static ssize_t btrfs_label_show(struct kobject *kobj,
 390                                 struct kobj_attribute *a, char *buf)
 391 {
 392         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 393         char *label = fs_info->super_copy->label;
 394         ssize_t ret;
 395
 396         spin_lock(&fs_info->super_lock);
 397         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 398         spin_unlock(&fs_info->super_lock);
 399
 400         return ret;
 401 }
 402
 403 static ssize_t btrfs_label_store(struct kobject *kobj,
 404                                  struct kobj_attribute *a,
 405                                  const char *buf, size_t len)
 406 {
 407         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 408         size_t p_len;
 409
 410         if (!fs_info)
 411                 return -EPERM;
 412
 413         if (sb_rdonly(fs_info->sb))
 414                 return -EROFS;
 415
 416         /*
 417          * p_len is the len until the first occurrence of either
 418          * '\n' or '\0'
 419          */
 420         p_len = strcspn(buf, "\n");
 421
 422         if (p_len >= BTRFS_LABEL_SIZE)
 423                 return -EINVAL;
 424
 425         spin_lock(&fs_info->super_lock);
 426         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 427         memcpy(fs_info->super_copy->label, buf, p_len);
 428         spin_unlock(&fs_info->super_lock);
 429
 430         /*
 431          * We don't want to do full transaction commit from inside sysfs
 432          */
 433         btrfs_set_pending(fs_info, COMMIT);
 434         wake_up_process(fs_info->transaction_kthread);
 435
 436         return len;
 437 }
 438 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 439
 440 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 441                                 struct kobj_attribute *a, char *buf)
 442 {
 443         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 444
 445         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 446 }
 447
 448 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 449
 450 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 451                                 struct kobj_attribute *a, char *buf)
 452 {
 453         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 454
 455         return snprintf(buf, PAGE_SIZE, "%u\n",
 456                         fs_info->super_copy->sectorsize);
 457 }
 458
 459 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 460
 461 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 462                                 struct kobj_attribute *a, char *buf)
 463 {
 464         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 465
 466         return snprintf(buf, PAGE_SIZE, "%u\n",
 467                         fs_info->super_copy->sectorsize);
 468 }
 469
 470 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 471
 472 static ssize_t quota_override_show(struct kobject *kobj,
 473                                    struct kobj_attribute *a, char *buf)
 474 {
 475         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 476         int quota_override;
 477
 478         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 479         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 480 }
 481
 482 static ssize_t quota_override_store(struct kobject *kobj,
 483                                     struct kobj_attribute *a,
 484                                     const char *buf, size_t len)
 485 {
 486         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 487         unsigned long knob;
 488         int err;
 489
 490         if (!fs_info)
 491                 return -EPERM;
 492
 493         if (!capable(CAP_SYS_RESOURCE))
 494                 return -EPERM;
 495
 496         err = kstrtoul(buf, 10, &knob);
 497         if (err)
 498                 return err;
 499         if (knob > 1)
 500                 return -EINVAL;
 501
 502         if (knob)
 503                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 504         else
 505                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 506
 507         return len;
 508 }
 509
 510 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 511
 512 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 513                                 struct kobj_attribute *a, char *buf)
 514 {
 515         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 516
 517         return snprintf(buf, PAGE_SIZE, "%pU\n",
 518                         fs_info->fs_devices->metadata_uuid);
 519 }
 520
 521 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 522
 523 static const struct attribute *btrfs_attrs[] = {
 524         BTRFS_ATTR_PTR(, label),
 525         BTRFS_ATTR_PTR(, nodesize),
 526         BTRFS_ATTR_PTR(, sectorsize),
 527         BTRFS_ATTR_PTR(, clone_alignment),
 528         BTRFS_ATTR_PTR(, quota_override),
 529         BTRFS_ATTR_PTR(, metadata_uuid),
 530         NULL,
 531 };
 532
 533 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 534 {
 535         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 536
 537         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 538         complete(&fs_devs->kobj_unregister);
 539 }
 540
 541 static struct kobj_type btrfs_ktype = {
 542         .sysfs_ops      = &kobj_sysfs_ops,
 543         .release        = btrfs_release_fsid_kobj,
 544 };
 545
 546 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 547 {
 548         if (kobj->ktype != &btrfs_ktype)
 549                 return NULL;
 550         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 551 }
 552
 553 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 554 {
 555         if (kobj->ktype != &btrfs_ktype)
 556                 return NULL;
 557         return to_fs_devs(kobj)->fs_info;
 558 }
 559
 560 #define NUM_FEATURE_BITS 64
 561 #define BTRFS_FEATURE_NAME_MAX 13
 562 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 563 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 564
 565 static const u64 supported_feature_masks[FEAT_MAX] = {
 566         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 567         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 568         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 569 };
 570
 571 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 572 {
 573         int set;
 574
 575         for (set = 0; set < FEAT_MAX; set++) {
 576                 int i;
 577                 struct attribute *attrs[2];
 578                 struct attribute_group agroup = {
 579                         .name = "features",
 580                         .attrs = attrs,
 581                 };
 582                 u64 features = get_features(fs_info, set);
 583                 features &= ~supported_feature_masks[set];
 584
 585                 if (!features)
 586                         continue;
 587
 588                 attrs[1] = NULL;
 589                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 590                         struct btrfs_feature_attr *fa;
 591
 592                         if (!(features & (1ULL << i)))
 593                                 continue;
 594
 595                         fa = &btrfs_feature_attrs[set][i];
 596                         attrs[0] = &fa->kobj_attr.attr;
 597                         if (add) {
 598                                 int ret;
 599                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 600                                                         &agroup);
 601                                 if (ret)
 602                                         return ret;
 603                         } else
 604                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 605                                                     &agroup);
 606                 }
 607
 608         }
 609         return 0;
 610 }
 611
 612 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 613 {
 614         if (fs_devs->device_dir_kobj) {
 615                 kobject_del(fs_devs->device_dir_kobj);
 616                 kobject_put(fs_devs->device_dir_kobj);
 617                 fs_devs->device_dir_kobj = NULL;
 618         }
 619
 620         if (fs_devs->fsid_kobj.state_initialized) {
 621                 kobject_del(&fs_devs->fsid_kobj);
 622                 kobject_put(&fs_devs->fsid_kobj);
 623                 wait_for_completion(&fs_devs->kobj_unregister);
 624         }
 625 }
 626
 627 /* when fs_devs is NULL it will remove all fsid kobject */
 628 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 629 {
 630         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 631
 632         if (fs_devs) {
 633                 __btrfs_sysfs_remove_fsid(fs_devs);
 634                 return;
 635         }
 636
 637         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 638                 __btrfs_sysfs_remove_fsid(fs_devs);
 639         }
 640 }
 641
 642 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 643 {
 644         btrfs_reset_fs_info_ptr(fs_info);
 645
 646         if (fs_info->space_info_kobj) {
 647                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 648                 kobject_del(fs_info->space_info_kobj);
 649                 kobject_put(fs_info->space_info_kobj);
 650         }
 651         addrm_unknown_feature_attrs(fs_info, false);
 652         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 653         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 654         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 655 }
 656
 657 const char * const btrfs_feature_set_names[FEAT_MAX] = {
 658         [FEAT_COMPAT]    = "compat",
 659         [FEAT_COMPAT_RO] = "compat_ro",
 660         [FEAT_INCOMPAT]  = "incompat",
 661 };
 662
 663 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 664 {
 665         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 666         int len = 0;
 667         int i;
 668         char *str;
 669
 670         str = kmalloc(bufsize, GFP_KERNEL);
 671         if (!str)
 672                 return str;
 673
 674         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 675                 const char *name;
 676
 677                 if (!(flags & (1ULL << i)))
 678                         continue;
 679
 680                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 681                 len += snprintf(str + len, bufsize - len, "%s%s",
 682                                 len ? "," : "", name);
 683         }
 684
 685         return str;
 686 }
 687
 688 static void init_feature_attrs(void)
 689 {
 690         struct btrfs_feature_attr *fa;
 691         int set, i;
 692
 693         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 694                      ARRAY_SIZE(btrfs_feature_attrs));
 695         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 696                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 697
 698         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 699         memset(btrfs_unknown_feature_names, 0,
 700                sizeof(btrfs_unknown_feature_names));
 701
 702         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 703                 struct btrfs_feature_attr *sfa;
 704                 struct attribute *a = btrfs_supported_feature_attrs[i];
 705                 int bit;
 706                 sfa = attr_to_btrfs_feature_attr(a);
 707                 bit = ilog2(sfa->feature_bit);
 708                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 709
 710                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 711         }
 712
 713         for (set = 0; set < FEAT_MAX; set++) {
 714                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 715                         char *name = btrfs_unknown_feature_names[set][i];
 716                         fa = &btrfs_feature_attrs[set][i];
 717
 718                         if (fa->kobj_attr.attr.name)
 719                                 continue;
 720
 721                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 722                                  btrfs_feature_set_names[set], i);
 723
 724                         fa->kobj_attr.attr.name = name;
 725                         fa->kobj_attr.attr.mode = S_IRUGO;
 726                         fa->feature_set = set;
 727                         fa->feature_bit = 1ULL << i;
 728                 }
 729         }
 730 }
 731
 732 /* when one_device is NULL, it removes all device links */
 733
 734 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 735                 struct btrfs_device *one_device)
 736 {
 737         struct hd_struct *disk;
 738         struct kobject *disk_kobj;
 739
 740         if (!fs_devices->device_dir_kobj)
 741                 return -EINVAL;
 742
 743         if (one_device && one_device->bdev) {
 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         if (one_device)
 752                 return 0;
 753
 754         list_for_each_entry(one_device,
 755                         &fs_devices->devices, dev_list) {
 756                 if (!one_device->bdev)
 757                         continue;
 758                 disk = one_device->bdev->bd_part;
 759                 disk_kobj = &part_to_dev(disk)->kobj;
 760
 761                 sysfs_remove_link(fs_devices->device_dir_kobj,
 762                                                 disk_kobj->name);
 763         }
 764
 765         return 0;
 766 }
 767
 768 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 769 {
 770         if (!fs_devs->device_dir_kobj)
 771                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 772                                                 &fs_devs->fsid_kobj);
 773
 774         if (!fs_devs->device_dir_kobj)
 775                 return -ENOMEM;
 776
 777         return 0;
 778 }
 779
 780 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 781                                 struct btrfs_device *one_device)
 782 {
 783         int error = 0;
 784         struct btrfs_device *dev;
 785
 786         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 787                 struct hd_struct *disk;
 788                 struct kobject *disk_kobj;
 789
 790                 if (!dev->bdev)
 791                         continue;
 792
 793                 if (one_device && one_device != dev)
 794                         continue;
 795
 796                 disk = dev->bdev->bd_part;
 797                 disk_kobj = &part_to_dev(disk)->kobj;
 798
 799                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 800                                           disk_kobj, disk_kobj->name);
 801                 if (error)
 802                         break;
 803         }
 804
 805         return error;
 806 }
 807
 808 /* /sys/fs/btrfs/ entry */
 809 static struct kset *btrfs_kset;
 810
 811 /* /sys/kernel/debug/btrfs */
 812 static struct dentry *btrfs_debugfs_root_dentry;
 813
 814 /* Debugging tunables and exported data */
 815 u64 btrfs_debugfs_test;
 816
 817 /*
 818  * Can be called by the device discovery thread.
 819  * And parent can be specified for seed device
 820  */
 821 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 822                                 struct kobject *parent)
 823 {
 824         int error;
 825
 826         init_completion(&fs_devs->kobj_unregister);
 827         fs_devs->fsid_kobj.kset = btrfs_kset;
 828         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 829                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 830         if (error) {
 831                 kobject_put(&fs_devs->fsid_kobj);
 832                 return error;
 833         }
 834
 835         return 0;
 836 }
 837
 838 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 839 {
 840         int error;
 841         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 842         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 843
 844         btrfs_set_fs_info_ptr(fs_info);
 845
 846         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 847         if (error)
 848                 return error;
 849
 850         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 851         if (error) {
 852                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 853                 return error;
 854         }
 855
 856         error = sysfs_create_group(fsid_kobj,
 857                                    &btrfs_feature_attr_group);
 858         if (error)
 859                 goto failure;
 860
 861         error = addrm_unknown_feature_attrs(fs_info, true);
 862         if (error)
 863                 goto failure;
 864
 865         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 866                                                   fsid_kobj);
 867         if (!fs_info->space_info_kobj) {
 868                 error = -ENOMEM;
 869                 goto failure;
 870         }
 871
 872         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 873         if (error)
 874                 goto failure;
 875
 876         return 0;
 877 failure:
 878         btrfs_sysfs_remove_mounted(fs_info);
 879         return error;
 880 }
 881
 882
 883 /*
 884  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 885  * values in superblock. Call after any changes to incompat/compat_ro flags
 886  */
 887 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 888                 u64 bit, enum btrfs_feature_set set)
 889 {
 890         struct btrfs_fs_devices *fs_devs;
 891         struct kobject *fsid_kobj;
 892         u64 features;
 893         int ret;
 894
 895         if (!fs_info)
 896                 return;
 897
 898         features = get_features(fs_info, set);
 899         ASSERT(bit & supported_feature_masks[set]);
 900
 901         fs_devs = fs_info->fs_devices;
 902         fsid_kobj = &fs_devs->fsid_kobj;
 903
 904         if (!fsid_kobj->state_initialized)
 905                 return;
 906
 907         /*
 908          * FIXME: this is too heavy to update just one value, ideally we'd like
 909          * to use sysfs_update_group but some refactoring is needed first.
 910          */
 911         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 912         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 913 }
 914
 915 static void btrfs_init_debugfs(void)
 916 {
 917 #ifdef CONFIG_DEBUG_FS
 918         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 919
 920         /*
 921          * Example code, how to export data through debugfs.
 922          *
 923          * file:        /sys/kernel/debug/btrfs/test
 924          * contents of: btrfs_debugfs_test
 925          */
 926 #ifdef CONFIG_BTRFS_DEBUG
 927         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
 928                         &btrfs_debugfs_test);
 929 #endif
 930
 931 #endif
 932 }
 933
 934 int __init btrfs_init_sysfs(void)
 935 {
 936         int ret;
 937
 938         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 939         if (!btrfs_kset)
 940                 return -ENOMEM;
 941
 942         btrfs_init_debugfs();
 943
 944         init_feature_attrs();
 945         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 946         if (ret)
 947                 goto out2;
 948         ret = sysfs_merge_group(&btrfs_kset->kobj,
 949                                 &btrfs_static_feature_attr_group);
 950         if (ret)
 951                 goto out_remove_group;
 952
 953         return 0;
 954
 955 out_remove_group:
 956         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 957 out2:
 958         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 959         kset_unregister(btrfs_kset);
 960
 961         return ret;
 962 }
 963
 964 void __cold btrfs_exit_sysfs(void)
 965 {
 966         sysfs_unmerge_group(&btrfs_kset->kobj,
 967                             &btrfs_static_feature_attr_group);
 968         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 969         kset_unregister(btrfs_kset);
 970         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 971 }
 972