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/sched/mm.h>
   8 #include <linux/slab.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/completion.h>
  11 #include <linux/kobject.h>
  12 #include <linux/bug.h>
  13
  14 #include "ctree.h"
  15 #include "disk-io.h"
  16 #include "transaction.h"
  17 #include "sysfs.h"
  18 #include "volumes.h"
  19 #include "space-info.h"
  20 #include "block-group.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_INCOMPAT(metadata_uuid, METADATA_UUID);
 197 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 198
 199 static struct attribute *btrfs_supported_feature_attrs[] = {
 200         BTRFS_FEAT_ATTR_PTR(mixed_backref),
 201         BTRFS_FEAT_ATTR_PTR(default_subvol),
 202         BTRFS_FEAT_ATTR_PTR(mixed_groups),
 203         BTRFS_FEAT_ATTR_PTR(compress_lzo),
 204         BTRFS_FEAT_ATTR_PTR(compress_zstd),
 205         BTRFS_FEAT_ATTR_PTR(big_metadata),
 206         BTRFS_FEAT_ATTR_PTR(extended_iref),
 207         BTRFS_FEAT_ATTR_PTR(raid56),
 208         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
 209         BTRFS_FEAT_ATTR_PTR(no_holes),
 210         BTRFS_FEAT_ATTR_PTR(metadata_uuid),
 211         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 212         NULL
 213 };
 214
 215 /*
 216  * Features which depend on feature bits and may differ between each fs.
 217  *
 218  * /sys/fs/btrfs/features lists all available features of this kernel while
 219  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 220  * can be changed online.
 221  */
 222 static const struct attribute_group btrfs_feature_attr_group = {
 223         .name = "features",
 224         .is_visible = btrfs_feature_visible,
 225         .attrs = btrfs_supported_feature_attrs,
 226 };
 227
 228 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 229                                  struct kobj_attribute *ka, char *buf)
 230 {
 231         return snprintf(buf, PAGE_SIZE, "0\n");
 232 }
 233 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 234
 235 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 236         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 237         NULL
 238 };
 239
 240 /*
 241  * Features which only depend on kernel version.
 242  *
 243  * These are listed in /sys/fs/btrfs/features along with
 244  * btrfs_feature_attr_group
 245  */
 246 static const struct attribute_group btrfs_static_feature_attr_group = {
 247         .name = "features",
 248         .attrs = btrfs_supported_static_feature_attrs,
 249 };
 250
 251 #ifdef CONFIG_BTRFS_DEBUG
 252
 253 /*
 254  * Runtime debugging exported via sysfs
 255  *
 256  * /sys/fs/btrfs/debug - applies to module or all filesystems
 257  * /sys/fs/btrfs/UUID  - applies only to the given filesystem
 258  */
 259 static struct attribute *btrfs_debug_feature_attrs[] = {
 260         NULL
 261 };
 262
 263 static const struct attribute_group btrfs_debug_feature_attr_group = {
 264         .name = "debug",
 265         .attrs = btrfs_debug_feature_attrs,
 266 };
 267
 268 #endif
 269
 270 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 271 {
 272         u64 val;
 273         if (lock)
 274                 spin_lock(lock);
 275         val = *value_ptr;
 276         if (lock)
 277                 spin_unlock(lock);
 278         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 279 }
 280
 281 static ssize_t global_rsv_size_show(struct kobject *kobj,
 282                                     struct kobj_attribute *ka, char *buf)
 283 {
 284         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 285         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 286         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 287 }
 288 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 289
 290 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 291                                         struct kobj_attribute *a, char *buf)
 292 {
 293         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 294         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 295         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 296 }
 297 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 298
 299 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 300 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 301
 302 static ssize_t raid_bytes_show(struct kobject *kobj,
 303                                struct kobj_attribute *attr, char *buf);
 304 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 305 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 306
 307 static ssize_t raid_bytes_show(struct kobject *kobj,
 308                                struct kobj_attribute *attr, char *buf)
 309
 310 {
 311         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 312         struct btrfs_block_group_cache *block_group;
 313         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 314         u64 val = 0;
 315
 316         down_read(&sinfo->groups_sem);
 317         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 318                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 319                         val += block_group->key.offset;
 320                 else
 321                         val += btrfs_block_group_used(&block_group->item);
 322         }
 323         up_read(&sinfo->groups_sem);
 324         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 325 }
 326
 327 static struct attribute *raid_attrs[] = {
 328         BTRFS_ATTR_PTR(raid, total_bytes),
 329         BTRFS_ATTR_PTR(raid, used_bytes),
 330         NULL
 331 };
 332 ATTRIBUTE_GROUPS(raid);
 333
 334 static void release_raid_kobj(struct kobject *kobj)
 335 {
 336         kfree(to_raid_kobj(kobj));
 337 }
 338
 339 static struct kobj_type btrfs_raid_ktype = {
 340         .sysfs_ops = &kobj_sysfs_ops,
 341         .release = release_raid_kobj,
 342         .default_groups = raid_groups,
 343 };
 344
 345 #define SPACE_INFO_ATTR(field)                                          \
 346 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 347                                              struct kobj_attribute *a,  \
 348                                              char *buf)                 \
 349 {                                                                       \
 350         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 351         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 352 }                                                                       \
 353 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 354
 355 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 356                                                        struct kobj_attribute *a,
 357                                                        char *buf)
 358 {
 359         struct btrfs_space_info *sinfo = to_space_info(kobj);
 360         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 361         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 362 }
 363
 364 SPACE_INFO_ATTR(flags);
 365 SPACE_INFO_ATTR(total_bytes);
 366 SPACE_INFO_ATTR(bytes_used);
 367 SPACE_INFO_ATTR(bytes_pinned);
 368 SPACE_INFO_ATTR(bytes_reserved);
 369 SPACE_INFO_ATTR(bytes_may_use);
 370 SPACE_INFO_ATTR(bytes_readonly);
 371 SPACE_INFO_ATTR(disk_used);
 372 SPACE_INFO_ATTR(disk_total);
 373 BTRFS_ATTR(space_info, total_bytes_pinned,
 374            btrfs_space_info_show_total_bytes_pinned);
 375
 376 static struct attribute *space_info_attrs[] = {
 377         BTRFS_ATTR_PTR(space_info, flags),
 378         BTRFS_ATTR_PTR(space_info, total_bytes),
 379         BTRFS_ATTR_PTR(space_info, bytes_used),
 380         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 381         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 382         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 383         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 384         BTRFS_ATTR_PTR(space_info, disk_used),
 385         BTRFS_ATTR_PTR(space_info, disk_total),
 386         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 387         NULL,
 388 };
 389 ATTRIBUTE_GROUPS(space_info);
 390
 391 static void space_info_release(struct kobject *kobj)
 392 {
 393         struct btrfs_space_info *sinfo = to_space_info(kobj);
 394         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 395         kfree(sinfo);
 396 }
 397
 398 static struct kobj_type space_info_ktype = {
 399         .sysfs_ops = &kobj_sysfs_ops,
 400         .release = space_info_release,
 401         .default_groups = space_info_groups,
 402 };
 403
 404 static const struct attribute *allocation_attrs[] = {
 405         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 406         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 407         NULL,
 408 };
 409
 410 static ssize_t btrfs_label_show(struct kobject *kobj,
 411                                 struct kobj_attribute *a, char *buf)
 412 {
 413         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 414         char *label = fs_info->super_copy->label;
 415         ssize_t ret;
 416
 417         spin_lock(&fs_info->super_lock);
 418         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 419         spin_unlock(&fs_info->super_lock);
 420
 421         return ret;
 422 }
 423
 424 static ssize_t btrfs_label_store(struct kobject *kobj,
 425                                  struct kobj_attribute *a,
 426                                  const char *buf, size_t len)
 427 {
 428         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 429         size_t p_len;
 430
 431         if (!fs_info)
 432                 return -EPERM;
 433
 434         if (sb_rdonly(fs_info->sb))
 435                 return -EROFS;
 436
 437         /*
 438          * p_len is the len until the first occurrence of either
 439          * '\n' or '\0'
 440          */
 441         p_len = strcspn(buf, "\n");
 442
 443         if (p_len >= BTRFS_LABEL_SIZE)
 444                 return -EINVAL;
 445
 446         spin_lock(&fs_info->super_lock);
 447         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 448         memcpy(fs_info->super_copy->label, buf, p_len);
 449         spin_unlock(&fs_info->super_lock);
 450
 451         /*
 452          * We don't want to do full transaction commit from inside sysfs
 453          */
 454         btrfs_set_pending(fs_info, COMMIT);
 455         wake_up_process(fs_info->transaction_kthread);
 456
 457         return len;
 458 }
 459 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 460
 461 static ssize_t btrfs_nodesize_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", fs_info->super_copy->nodesize);
 467 }
 468
 469 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 470
 471 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 472                                 struct kobj_attribute *a, char *buf)
 473 {
 474         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 475
 476         return snprintf(buf, PAGE_SIZE, "%u\n",
 477                         fs_info->super_copy->sectorsize);
 478 }
 479
 480 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 481
 482 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 483                                 struct kobj_attribute *a, char *buf)
 484 {
 485         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 486
 487         return snprintf(buf, PAGE_SIZE, "%u\n",
 488                         fs_info->super_copy->sectorsize);
 489 }
 490
 491 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 492
 493 static ssize_t quota_override_show(struct kobject *kobj,
 494                                    struct kobj_attribute *a, char *buf)
 495 {
 496         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 497         int quota_override;
 498
 499         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 500         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 501 }
 502
 503 static ssize_t quota_override_store(struct kobject *kobj,
 504                                     struct kobj_attribute *a,
 505                                     const char *buf, size_t len)
 506 {
 507         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 508         unsigned long knob;
 509         int err;
 510
 511         if (!fs_info)
 512                 return -EPERM;
 513
 514         if (!capable(CAP_SYS_RESOURCE))
 515                 return -EPERM;
 516
 517         err = kstrtoul(buf, 10, &knob);
 518         if (err)
 519                 return err;
 520         if (knob > 1)
 521                 return -EINVAL;
 522
 523         if (knob)
 524                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 525         else
 526                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 527
 528         return len;
 529 }
 530
 531 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 532
 533 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 534                                 struct kobj_attribute *a, char *buf)
 535 {
 536         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 537
 538         return snprintf(buf, PAGE_SIZE, "%pU\n",
 539                         fs_info->fs_devices->metadata_uuid);
 540 }
 541
 542 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 543
 544 static const struct attribute *btrfs_attrs[] = {
 545         BTRFS_ATTR_PTR(, label),
 546         BTRFS_ATTR_PTR(, nodesize),
 547         BTRFS_ATTR_PTR(, sectorsize),
 548         BTRFS_ATTR_PTR(, clone_alignment),
 549         BTRFS_ATTR_PTR(, quota_override),
 550         BTRFS_ATTR_PTR(, metadata_uuid),
 551         NULL,
 552 };
 553
 554 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 555 {
 556         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 557
 558         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 559         complete(&fs_devs->kobj_unregister);
 560 }
 561
 562 static struct kobj_type btrfs_ktype = {
 563         .sysfs_ops      = &kobj_sysfs_ops,
 564         .release        = btrfs_release_fsid_kobj,
 565 };
 566
 567 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 568 {
 569         if (kobj->ktype != &btrfs_ktype)
 570                 return NULL;
 571         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 572 }
 573
 574 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 575 {
 576         if (kobj->ktype != &btrfs_ktype)
 577                 return NULL;
 578         return to_fs_devs(kobj)->fs_info;
 579 }
 580
 581 #define NUM_FEATURE_BITS 64
 582 #define BTRFS_FEATURE_NAME_MAX 13
 583 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 584 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 585
 586 static const u64 supported_feature_masks[FEAT_MAX] = {
 587         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 588         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 589         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 590 };
 591
 592 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 593 {
 594         int set;
 595
 596         for (set = 0; set < FEAT_MAX; set++) {
 597                 int i;
 598                 struct attribute *attrs[2];
 599                 struct attribute_group agroup = {
 600                         .name = "features",
 601                         .attrs = attrs,
 602                 };
 603                 u64 features = get_features(fs_info, set);
 604                 features &= ~supported_feature_masks[set];
 605
 606                 if (!features)
 607                         continue;
 608
 609                 attrs[1] = NULL;
 610                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 611                         struct btrfs_feature_attr *fa;
 612
 613                         if (!(features & (1ULL << i)))
 614                                 continue;
 615
 616                         fa = &btrfs_feature_attrs[set][i];
 617                         attrs[0] = &fa->kobj_attr.attr;
 618                         if (add) {
 619                                 int ret;
 620                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 621                                                         &agroup);
 622                                 if (ret)
 623                                         return ret;
 624                         } else
 625                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 626                                                     &agroup);
 627                 }
 628
 629         }
 630         return 0;
 631 }
 632
 633 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 634 {
 635         if (fs_devs->device_dir_kobj) {
 636                 kobject_del(fs_devs->device_dir_kobj);
 637                 kobject_put(fs_devs->device_dir_kobj);
 638                 fs_devs->device_dir_kobj = NULL;
 639         }
 640
 641         if (fs_devs->fsid_kobj.state_initialized) {
 642                 kobject_del(&fs_devs->fsid_kobj);
 643                 kobject_put(&fs_devs->fsid_kobj);
 644                 wait_for_completion(&fs_devs->kobj_unregister);
 645         }
 646 }
 647
 648 /* when fs_devs is NULL it will remove all fsid kobject */
 649 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 650 {
 651         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 652
 653         if (fs_devs) {
 654                 __btrfs_sysfs_remove_fsid(fs_devs);
 655                 return;
 656         }
 657
 658         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 659                 __btrfs_sysfs_remove_fsid(fs_devs);
 660         }
 661 }
 662
 663 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 664 {
 665         btrfs_reset_fs_info_ptr(fs_info);
 666
 667         if (fs_info->space_info_kobj) {
 668                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 669                 kobject_del(fs_info->space_info_kobj);
 670                 kobject_put(fs_info->space_info_kobj);
 671         }
 672         addrm_unknown_feature_attrs(fs_info, false);
 673         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 674         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 675         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 676 }
 677
 678 static const char * const btrfs_feature_set_names[FEAT_MAX] = {
 679         [FEAT_COMPAT]    = "compat",
 680         [FEAT_COMPAT_RO] = "compat_ro",
 681         [FEAT_INCOMPAT]  = "incompat",
 682 };
 683
 684 const char * const btrfs_feature_set_name(enum btrfs_feature_set set)
 685 {
 686         return btrfs_feature_set_names[set];
 687 }
 688
 689 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 690 {
 691         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 692         int len = 0;
 693         int i;
 694         char *str;
 695
 696         str = kmalloc(bufsize, GFP_KERNEL);
 697         if (!str)
 698                 return str;
 699
 700         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 701                 const char *name;
 702
 703                 if (!(flags & (1ULL << i)))
 704                         continue;
 705
 706                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 707                 len += snprintf(str + len, bufsize - len, "%s%s",
 708                                 len ? "," : "", name);
 709         }
 710
 711         return str;
 712 }
 713
 714 static void init_feature_attrs(void)
 715 {
 716         struct btrfs_feature_attr *fa;
 717         int set, i;
 718
 719         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 720                      ARRAY_SIZE(btrfs_feature_attrs));
 721         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 722                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 723
 724         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 725         memset(btrfs_unknown_feature_names, 0,
 726                sizeof(btrfs_unknown_feature_names));
 727
 728         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 729                 struct btrfs_feature_attr *sfa;
 730                 struct attribute *a = btrfs_supported_feature_attrs[i];
 731                 int bit;
 732                 sfa = attr_to_btrfs_feature_attr(a);
 733                 bit = ilog2(sfa->feature_bit);
 734                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 735
 736                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 737         }
 738
 739         for (set = 0; set < FEAT_MAX; set++) {
 740                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 741                         char *name = btrfs_unknown_feature_names[set][i];
 742                         fa = &btrfs_feature_attrs[set][i];
 743
 744                         if (fa->kobj_attr.attr.name)
 745                                 continue;
 746
 747                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 748                                  btrfs_feature_set_names[set], i);
 749
 750                         fa->kobj_attr.attr.name = name;
 751                         fa->kobj_attr.attr.mode = S_IRUGO;
 752                         fa->feature_set = set;
 753                         fa->feature_bit = 1ULL << i;
 754                 }
 755         }
 756 }
 757
 758 /*
 759  * Create a sysfs entry for a given block group type at path
 760  * /sys/fs/btrfs/UUID/allocation/data/TYPE
 761  */
 762 void btrfs_sysfs_add_block_group_type(struct btrfs_block_group_cache *cache)
 763 {
 764         struct btrfs_fs_info *fs_info = cache->fs_info;
 765         struct btrfs_space_info *space_info = cache->space_info;
 766         struct raid_kobject *rkobj;
 767         const int index = btrfs_bg_flags_to_raid_index(cache->flags);
 768         unsigned int nofs_flag;
 769         int ret;
 770
 771         /*
 772          * Setup a NOFS context because kobject_add(), deep in its call chain,
 773          * does GFP_KERNEL allocations, and we are often called in a context
 774          * where if reclaim is triggered we can deadlock (we are either holding
 775          * a transaction handle or some lock required for a transaction
 776          * commit).
 777          */
 778         nofs_flag = memalloc_nofs_save();
 779
 780         rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
 781         if (!rkobj) {
 782                 memalloc_nofs_restore(nofs_flag);
 783                 btrfs_warn(cache->fs_info,
 784                                 "couldn't alloc memory for raid level kobject");
 785                 return;
 786         }
 787
 788         rkobj->flags = cache->flags;
 789         kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
 790         ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
 791                           btrfs_bg_type_to_raid_name(rkobj->flags));
 792         memalloc_nofs_restore(nofs_flag);
 793         if (ret) {
 794                 kobject_put(&rkobj->kobj);
 795                 btrfs_warn(fs_info,
 796                         "failed to add kobject for block cache, ignoring");
 797                 return;
 798         }
 799
 800         space_info->block_group_kobjs[index] = &rkobj->kobj;
 801 }
 802
 803 static const char *alloc_name(u64 flags)
 804 {
 805         switch (flags) {
 806         case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
 807                 return "mixed";
 808         case BTRFS_BLOCK_GROUP_METADATA:
 809                 return "metadata";
 810         case BTRFS_BLOCK_GROUP_DATA:
 811                 return "data";
 812         case BTRFS_BLOCK_GROUP_SYSTEM:
 813                 return "system";
 814         default:
 815                 WARN_ON(1);
 816                 return "invalid-combination";
 817         };
 818 }
 819
 820 /*
 821  * Create a sysfs entry for a space info type at path
 822  * /sys/fs/btrfs/UUID/allocation/TYPE
 823  */
 824 int btrfs_sysfs_add_space_info_type(struct btrfs_fs_info *fs_info,
 825                                     struct btrfs_space_info *space_info)
 826 {
 827         int ret;
 828
 829         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
 830                                    fs_info->space_info_kobj, "%s",
 831                                    alloc_name(space_info->flags));
 832         if (ret) {
 833                 kobject_put(&space_info->kobj);
 834                 return ret;
 835         }
 836
 837         return 0;
 838 }
 839
 840 /* when one_device is NULL, it removes all device links */
 841
 842 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 843                 struct btrfs_device *one_device)
 844 {
 845         struct hd_struct *disk;
 846         struct kobject *disk_kobj;
 847
 848         if (!fs_devices->device_dir_kobj)
 849                 return -EINVAL;
 850
 851         if (one_device && one_device->bdev) {
 852                 disk = one_device->bdev->bd_part;
 853                 disk_kobj = &part_to_dev(disk)->kobj;
 854
 855                 sysfs_remove_link(fs_devices->device_dir_kobj,
 856                                                 disk_kobj->name);
 857         }
 858
 859         if (one_device)
 860                 return 0;
 861
 862         list_for_each_entry(one_device,
 863                         &fs_devices->devices, dev_list) {
 864                 if (!one_device->bdev)
 865                         continue;
 866                 disk = one_device->bdev->bd_part;
 867                 disk_kobj = &part_to_dev(disk)->kobj;
 868
 869                 sysfs_remove_link(fs_devices->device_dir_kobj,
 870                                                 disk_kobj->name);
 871         }
 872
 873         return 0;
 874 }
 875
 876 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 877 {
 878         if (!fs_devs->device_dir_kobj)
 879                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 880                                                 &fs_devs->fsid_kobj);
 881
 882         if (!fs_devs->device_dir_kobj)
 883                 return -ENOMEM;
 884
 885         return 0;
 886 }
 887
 888 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 889                                 struct btrfs_device *one_device)
 890 {
 891         int error = 0;
 892         struct btrfs_device *dev;
 893
 894         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 895                 struct hd_struct *disk;
 896                 struct kobject *disk_kobj;
 897
 898                 if (!dev->bdev)
 899                         continue;
 900
 901                 if (one_device && one_device != dev)
 902                         continue;
 903
 904                 disk = dev->bdev->bd_part;
 905                 disk_kobj = &part_to_dev(disk)->kobj;
 906
 907                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 908                                           disk_kobj, disk_kobj->name);
 909                 if (error)
 910                         break;
 911         }
 912
 913         return error;
 914 }
 915
 916 /* /sys/fs/btrfs/ entry */
 917 static struct kset *btrfs_kset;
 918
 919 /*
 920  * Can be called by the device discovery thread.
 921  * And parent can be specified for seed device
 922  */
 923 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 924                                 struct kobject *parent)
 925 {
 926         int error;
 927
 928         init_completion(&fs_devs->kobj_unregister);
 929         fs_devs->fsid_kobj.kset = btrfs_kset;
 930         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 931                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 932         if (error) {
 933                 kobject_put(&fs_devs->fsid_kobj);
 934                 return error;
 935         }
 936
 937         return 0;
 938 }
 939
 940 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 941 {
 942         int error;
 943         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 944         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 945
 946         btrfs_set_fs_info_ptr(fs_info);
 947
 948         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 949         if (error)
 950                 return error;
 951
 952         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 953         if (error) {
 954                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 955                 return error;
 956         }
 957
 958         error = sysfs_create_group(fsid_kobj,
 959                                    &btrfs_feature_attr_group);
 960         if (error)
 961                 goto failure;
 962
 963 #ifdef CONFIG_BTRFS_DEBUG
 964         error = sysfs_create_group(fsid_kobj,
 965                                    &btrfs_debug_feature_attr_group);
 966         if (error)
 967                 goto failure;
 968 #endif
 969
 970         error = addrm_unknown_feature_attrs(fs_info, true);
 971         if (error)
 972                 goto failure;
 973
 974         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 975                                                   fsid_kobj);
 976         if (!fs_info->space_info_kobj) {
 977                 error = -ENOMEM;
 978                 goto failure;
 979         }
 980
 981         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 982         if (error)
 983                 goto failure;
 984
 985         return 0;
 986 failure:
 987         btrfs_sysfs_remove_mounted(fs_info);
 988         return error;
 989 }
 990
 991
 992 /*
 993  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 994  * values in superblock. Call after any changes to incompat/compat_ro flags
 995  */
 996 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 997                 u64 bit, enum btrfs_feature_set set)
 998 {
 999         struct btrfs_fs_devices *fs_devs;
1000         struct kobject *fsid_kobj;
1001         u64 features;
1002         int ret;
1003
1004         if (!fs_info)
1005                 return;
1006
1007         features = get_features(fs_info, set);
1008         ASSERT(bit & supported_feature_masks[set]);
1009
1010         fs_devs = fs_info->fs_devices;
1011         fsid_kobj = &fs_devs->fsid_kobj;
1012
1013         if (!fsid_kobj->state_initialized)
1014                 return;
1015
1016         /*
1017          * FIXME: this is too heavy to update just one value, ideally we'd like
1018          * to use sysfs_update_group but some refactoring is needed first.
1019          */
1020         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
1021         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
1022 }
1023
1024 int __init btrfs_init_sysfs(void)
1025 {
1026         int ret;
1027
1028         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
1029         if (!btrfs_kset)
1030                 return -ENOMEM;
1031
1032         init_feature_attrs();
1033         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1034         if (ret)
1035                 goto out2;
1036         ret = sysfs_merge_group(&btrfs_kset->kobj,
1037                                 &btrfs_static_feature_attr_group);
1038         if (ret)
1039                 goto out_remove_group;
1040
1041 #ifdef CONFIG_BTRFS_DEBUG
1042         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_debug_feature_attr_group);
1043         if (ret)
1044                 goto out2;
1045 #endif
1046
1047         return 0;
1048
1049 out_remove_group:
1050         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1051 out2:
1052         kset_unregister(btrfs_kset);
1053
1054         return ret;
1055 }
1056
1057 void __cold btrfs_exit_sysfs(void)
1058 {
1059         sysfs_unmerge_group(&btrfs_kset->kobj,
1060                             &btrfs_static_feature_attr_group);
1061         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
1062         kset_unregister(btrfs_kset);
1063 }
1064