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 #include "space-info.h"
  20
  21 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
  22 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj);
  23
  24 static u64 get_features(struct btrfs_fs_info *fs_info,
  25                         enum btrfs_feature_set set)
  26 {
  27         struct btrfs_super_block *disk_super = fs_info->super_copy;
  28         if (set == FEAT_COMPAT)
  29                 return btrfs_super_compat_flags(disk_super);
  30         else if (set == FEAT_COMPAT_RO)
  31                 return btrfs_super_compat_ro_flags(disk_super);
  32         else
  33                 return btrfs_super_incompat_flags(disk_super);
  34 }
  35
  36 static void set_features(struct btrfs_fs_info *fs_info,
  37                          enum btrfs_feature_set set, u64 features)
  38 {
  39         struct btrfs_super_block *disk_super = fs_info->super_copy;
  40         if (set == FEAT_COMPAT)
  41                 btrfs_set_super_compat_flags(disk_super, features);
  42         else if (set == FEAT_COMPAT_RO)
  43                 btrfs_set_super_compat_ro_flags(disk_super, features);
  44         else
  45                 btrfs_set_super_incompat_flags(disk_super, features);
  46 }
  47
  48 static int can_modify_feature(struct btrfs_feature_attr *fa)
  49 {
  50         int val = 0;
  51         u64 set, clear;
  52         switch (fa->feature_set) {
  53         case FEAT_COMPAT:
  54                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
  55                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
  56                 break;
  57         case FEAT_COMPAT_RO:
  58                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
  59                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
  60                 break;
  61         case FEAT_INCOMPAT:
  62                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
  63                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
  64                 break;
  65         default:
  66                 pr_warn("btrfs: sysfs: unknown feature set %d\n",
  67                                 fa->feature_set);
  68                 return 0;
  69         }
  70
  71         if (set & fa->feature_bit)
  72                 val |= 1;
  73         if (clear & fa->feature_bit)
  74                 val |= 2;
  75
  76         return val;
  77 }
  78
  79 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  80                                        struct kobj_attribute *a, char *buf)
  81 {
  82         int val = 0;
  83         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  84         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
  85         if (fs_info) {
  86                 u64 features = get_features(fs_info, fa->feature_set);
  87                 if (features & fa->feature_bit)
  88                         val = 1;
  89         } else
  90                 val = can_modify_feature(fa);
  91
  92         return snprintf(buf, PAGE_SIZE, "%d\n", val);
  93 }
  94
  95 static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
  96                                         struct kobj_attribute *a,
  97                                         const char *buf, size_t count)
  98 {
  99         struct btrfs_fs_info *fs_info;
 100         struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
 101         u64 features, set, clear;
 102         unsigned long val;
 103         int ret;
 104
 105         fs_info = to_fs_info(kobj);
 106         if (!fs_info)
 107                 return -EPERM;
 108
 109         if (sb_rdonly(fs_info->sb))
 110                 return -EROFS;
 111
 112         ret = kstrtoul(skip_spaces(buf), 0, &val);
 113         if (ret)
 114                 return ret;
 115
 116         if (fa->feature_set == FEAT_COMPAT) {
 117                 set = BTRFS_FEATURE_COMPAT_SAFE_SET;
 118                 clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
 119         } else if (fa->feature_set == FEAT_COMPAT_RO) {
 120                 set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
 121                 clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
 122         } else {
 123                 set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
 124                 clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
 125         }
 126
 127         features = get_features(fs_info, fa->feature_set);
 128
 129         /* Nothing to do */
 130         if ((val && (features & fa->feature_bit)) ||
 131             (!val && !(features & fa->feature_bit)))
 132                 return count;
 133
 134         if ((val && !(set & fa->feature_bit)) ||
 135             (!val && !(clear & fa->feature_bit))) {
 136                 btrfs_info(fs_info,
 137                         "%sabling feature %s on mounted fs is not supported.",
 138                         val ? "En" : "Dis", fa->kobj_attr.attr.name);
 139                 return -EPERM;
 140         }
 141
 142         btrfs_info(fs_info, "%s %s feature flag",
 143                    val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
 144
 145         spin_lock(&fs_info->super_lock);
 146         features = get_features(fs_info, fa->feature_set);
 147         if (val)
 148                 features |= fa->feature_bit;
 149         else
 150                 features &= ~fa->feature_bit;
 151         set_features(fs_info, fa->feature_set, features);
 152         spin_unlock(&fs_info->super_lock);
 153
 154         /*
 155          * We don't want to do full transaction commit from inside sysfs
 156          */
 157         btrfs_set_pending(fs_info, COMMIT);
 158         wake_up_process(fs_info->transaction_kthread);
 159
 160         return count;
 161 }
 162
 163 static umode_t btrfs_feature_visible(struct kobject *kobj,
 164                                      struct attribute *attr, int unused)
 165 {
 166         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 167         umode_t mode = attr->mode;
 168
 169         if (fs_info) {
 170                 struct btrfs_feature_attr *fa;
 171                 u64 features;
 172
 173                 fa = attr_to_btrfs_feature_attr(attr);
 174                 features = get_features(fs_info, fa->feature_set);
 175
 176                 if (can_modify_feature(fa))
 177                         mode |= S_IWUSR;
 178                 else if (!(features & fa->feature_bit))
 179                         mode = 0;
 180         }
 181
 182         return mode;
 183 }
 184
 185 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
 186 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
 187 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
 188 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
 189 BTRFS_FEAT_ATTR_INCOMPAT(compress_zstd, COMPRESS_ZSTD);
 190 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
 191 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
 192 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
 193 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
 194 BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 195 BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
 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(metadata_uuid),
 210         BTRFS_FEAT_ATTR_PTR(free_space_tree),
 211         NULL
 212 };
 213
 214 /*
 215  * Features which depend on feature bits and may differ between each fs.
 216  *
 217  * /sys/fs/btrfs/features lists all available features of this kernel while
 218  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 219  * can be changed online.
 220  */
 221 static const struct attribute_group btrfs_feature_attr_group = {
 222         .name = "features",
 223         .is_visible = btrfs_feature_visible,
 224         .attrs = btrfs_supported_feature_attrs,
 225 };
 226
 227 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 228                                  struct kobj_attribute *ka, char *buf)
 229 {
 230         return snprintf(buf, PAGE_SIZE, "0\n");
 231 }
 232 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 233
 234 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 235         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 236         NULL
 237 };
 238
 239 /*
 240  * Features which only depend on kernel version.
 241  *
 242  * These are listed in /sys/fs/btrfs/features along with
 243  * btrfs_feature_attr_group
 244  */
 245 static const struct attribute_group btrfs_static_feature_attr_group = {
 246         .name = "features",
 247         .attrs = btrfs_supported_static_feature_attrs,
 248 };
 249
 250 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 251 {
 252         u64 val;
 253         if (lock)
 254                 spin_lock(lock);
 255         val = *value_ptr;
 256         if (lock)
 257                 spin_unlock(lock);
 258         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 259 }
 260
 261 static ssize_t global_rsv_size_show(struct kobject *kobj,
 262                                     struct kobj_attribute *ka, char *buf)
 263 {
 264         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 265         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 266         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 267 }
 268 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 269
 270 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 271                                         struct kobj_attribute *a, char *buf)
 272 {
 273         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 274         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 275         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 276 }
 277 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 278
 279 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 280 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 281
 282 static ssize_t raid_bytes_show(struct kobject *kobj,
 283                                struct kobj_attribute *attr, char *buf);
 284 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 285 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 286
 287 static ssize_t raid_bytes_show(struct kobject *kobj,
 288                                struct kobj_attribute *attr, char *buf)
 289
 290 {
 291         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 292         struct btrfs_block_group_cache *block_group;
 293         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 294         u64 val = 0;
 295
 296         down_read(&sinfo->groups_sem);
 297         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 298                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 299                         val += block_group->key.offset;
 300                 else
 301                         val += btrfs_block_group_used(&block_group->item);
 302         }
 303         up_read(&sinfo->groups_sem);
 304         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 305 }
 306
 307 static struct attribute *raid_attrs[] = {
 308         BTRFS_ATTR_PTR(raid, total_bytes),
 309         BTRFS_ATTR_PTR(raid, used_bytes),
 310         NULL
 311 };
 312 ATTRIBUTE_GROUPS(raid);
 313
 314 static void release_raid_kobj(struct kobject *kobj)
 315 {
 316         kfree(to_raid_kobj(kobj));
 317 }
 318
 319 struct kobj_type btrfs_raid_ktype = {
 320         .sysfs_ops = &kobj_sysfs_ops,
 321         .release = release_raid_kobj,
 322         .default_groups = raid_groups,
 323 };
 324
 325 #define SPACE_INFO_ATTR(field)                                          \
 326 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 327                                              struct kobj_attribute *a,  \
 328                                              char *buf)                 \
 329 {                                                                       \
 330         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 331         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 332 }                                                                       \
 333 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 334
 335 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 336                                                        struct kobj_attribute *a,
 337                                                        char *buf)
 338 {
 339         struct btrfs_space_info *sinfo = to_space_info(kobj);
 340         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 341         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 342 }
 343
 344 SPACE_INFO_ATTR(flags);
 345 SPACE_INFO_ATTR(total_bytes);
 346 SPACE_INFO_ATTR(bytes_used);
 347 SPACE_INFO_ATTR(bytes_pinned);
 348 SPACE_INFO_ATTR(bytes_reserved);
 349 SPACE_INFO_ATTR(bytes_may_use);
 350 SPACE_INFO_ATTR(bytes_readonly);
 351 SPACE_INFO_ATTR(disk_used);
 352 SPACE_INFO_ATTR(disk_total);
 353 BTRFS_ATTR(space_info, total_bytes_pinned,
 354            btrfs_space_info_show_total_bytes_pinned);
 355
 356 static struct attribute *space_info_attrs[] = {
 357         BTRFS_ATTR_PTR(space_info, flags),
 358         BTRFS_ATTR_PTR(space_info, total_bytes),
 359         BTRFS_ATTR_PTR(space_info, bytes_used),
 360         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 361         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 362         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 363         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 364         BTRFS_ATTR_PTR(space_info, disk_used),
 365         BTRFS_ATTR_PTR(space_info, disk_total),
 366         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 367         NULL,
 368 };
 369 ATTRIBUTE_GROUPS(space_info);
 370
 371 static void space_info_release(struct kobject *kobj)
 372 {
 373         struct btrfs_space_info *sinfo = to_space_info(kobj);
 374         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 375         kfree(sinfo);
 376 }
 377
 378 struct kobj_type space_info_ktype = {
 379         .sysfs_ops = &kobj_sysfs_ops,
 380         .release = space_info_release,
 381         .default_groups = space_info_groups,
 382 };
 383
 384 static const struct attribute *allocation_attrs[] = {
 385         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 386         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 387         NULL,
 388 };
 389
 390 static ssize_t btrfs_label_show(struct kobject *kobj,
 391                                 struct kobj_attribute *a, char *buf)
 392 {
 393         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 394         char *label = fs_info->super_copy->label;
 395         ssize_t ret;
 396
 397         spin_lock(&fs_info->super_lock);
 398         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 399         spin_unlock(&fs_info->super_lock);
 400
 401         return ret;
 402 }
 403
 404 static ssize_t btrfs_label_store(struct kobject *kobj,
 405                                  struct kobj_attribute *a,
 406                                  const char *buf, size_t len)
 407 {
 408         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 409         size_t p_len;
 410
 411         if (!fs_info)
 412                 return -EPERM;
 413
 414         if (sb_rdonly(fs_info->sb))
 415                 return -EROFS;
 416
 417         /*
 418          * p_len is the len until the first occurrence of either
 419          * '\n' or '\0'
 420          */
 421         p_len = strcspn(buf, "\n");
 422
 423         if (p_len >= BTRFS_LABEL_SIZE)
 424                 return -EINVAL;
 425
 426         spin_lock(&fs_info->super_lock);
 427         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 428         memcpy(fs_info->super_copy->label, buf, p_len);
 429         spin_unlock(&fs_info->super_lock);
 430
 431         /*
 432          * We don't want to do full transaction commit from inside sysfs
 433          */
 434         btrfs_set_pending(fs_info, COMMIT);
 435         wake_up_process(fs_info->transaction_kthread);
 436
 437         return len;
 438 }
 439 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 440
 441 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 442                                 struct kobj_attribute *a, char *buf)
 443 {
 444         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 445
 446         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 447 }
 448
 449 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 450
 451 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 452                                 struct kobj_attribute *a, char *buf)
 453 {
 454         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 455
 456         return snprintf(buf, PAGE_SIZE, "%u\n",
 457                         fs_info->super_copy->sectorsize);
 458 }
 459
 460 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 461
 462 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 463                                 struct kobj_attribute *a, char *buf)
 464 {
 465         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 466
 467         return snprintf(buf, PAGE_SIZE, "%u\n",
 468                         fs_info->super_copy->sectorsize);
 469 }
 470
 471 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 472
 473 static ssize_t quota_override_show(struct kobject *kobj,
 474                                    struct kobj_attribute *a, char *buf)
 475 {
 476         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 477         int quota_override;
 478
 479         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 480         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 481 }
 482
 483 static ssize_t quota_override_store(struct kobject *kobj,
 484                                     struct kobj_attribute *a,
 485                                     const char *buf, size_t len)
 486 {
 487         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 488         unsigned long knob;
 489         int err;
 490
 491         if (!fs_info)
 492                 return -EPERM;
 493
 494         if (!capable(CAP_SYS_RESOURCE))
 495                 return -EPERM;
 496
 497         err = kstrtoul(buf, 10, &knob);
 498         if (err)
 499                 return err;
 500         if (knob > 1)
 501                 return -EINVAL;
 502
 503         if (knob)
 504                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 505         else
 506                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 507
 508         return len;
 509 }
 510
 511 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 512
 513 static ssize_t btrfs_metadata_uuid_show(struct kobject *kobj,
 514                                 struct kobj_attribute *a, char *buf)
 515 {
 516         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 517
 518         return snprintf(buf, PAGE_SIZE, "%pU\n",
 519                         fs_info->fs_devices->metadata_uuid);
 520 }
 521
 522 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 523
 524 static const struct attribute *btrfs_attrs[] = {
 525         BTRFS_ATTR_PTR(, label),
 526         BTRFS_ATTR_PTR(, nodesize),
 527         BTRFS_ATTR_PTR(, sectorsize),
 528         BTRFS_ATTR_PTR(, clone_alignment),
 529         BTRFS_ATTR_PTR(, quota_override),
 530         BTRFS_ATTR_PTR(, metadata_uuid),
 531         NULL,
 532 };
 533
 534 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 535 {
 536         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 537
 538         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 539         complete(&fs_devs->kobj_unregister);
 540 }
 541
 542 static struct kobj_type btrfs_ktype = {
 543         .sysfs_ops      = &kobj_sysfs_ops,
 544         .release        = btrfs_release_fsid_kobj,
 545 };
 546
 547 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 548 {
 549         if (kobj->ktype != &btrfs_ktype)
 550                 return NULL;
 551         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 552 }
 553
 554 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 555 {
 556         if (kobj->ktype != &btrfs_ktype)
 557                 return NULL;
 558         return to_fs_devs(kobj)->fs_info;
 559 }
 560
 561 #define NUM_FEATURE_BITS 64
 562 #define BTRFS_FEATURE_NAME_MAX 13
 563 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 564 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 565
 566 static const u64 supported_feature_masks[FEAT_MAX] = {
 567         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 568         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 569         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 570 };
 571
 572 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 573 {
 574         int set;
 575
 576         for (set = 0; set < FEAT_MAX; set++) {
 577                 int i;
 578                 struct attribute *attrs[2];
 579                 struct attribute_group agroup = {
 580                         .name = "features",
 581                         .attrs = attrs,
 582                 };
 583                 u64 features = get_features(fs_info, set);
 584                 features &= ~supported_feature_masks[set];
 585
 586                 if (!features)
 587                         continue;
 588
 589                 attrs[1] = NULL;
 590                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 591                         struct btrfs_feature_attr *fa;
 592
 593                         if (!(features & (1ULL << i)))
 594                                 continue;
 595
 596                         fa = &btrfs_feature_attrs[set][i];
 597                         attrs[0] = &fa->kobj_attr.attr;
 598                         if (add) {
 599                                 int ret;
 600                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 601                                                         &agroup);
 602                                 if (ret)
 603                                         return ret;
 604                         } else
 605                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 606                                                     &agroup);
 607                 }
 608
 609         }
 610         return 0;
 611 }
 612
 613 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 614 {
 615         if (fs_devs->device_dir_kobj) {
 616                 kobject_del(fs_devs->device_dir_kobj);
 617                 kobject_put(fs_devs->device_dir_kobj);
 618                 fs_devs->device_dir_kobj = NULL;
 619         }
 620
 621         if (fs_devs->fsid_kobj.state_initialized) {
 622                 kobject_del(&fs_devs->fsid_kobj);
 623                 kobject_put(&fs_devs->fsid_kobj);
 624                 wait_for_completion(&fs_devs->kobj_unregister);
 625         }
 626 }
 627
 628 /* when fs_devs is NULL it will remove all fsid kobject */
 629 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 630 {
 631         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 632
 633         if (fs_devs) {
 634                 __btrfs_sysfs_remove_fsid(fs_devs);
 635                 return;
 636         }
 637
 638         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 639                 __btrfs_sysfs_remove_fsid(fs_devs);
 640         }
 641 }
 642
 643 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 644 {
 645         btrfs_reset_fs_info_ptr(fs_info);
 646
 647         if (fs_info->space_info_kobj) {
 648                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 649                 kobject_del(fs_info->space_info_kobj);
 650                 kobject_put(fs_info->space_info_kobj);
 651         }
 652         addrm_unknown_feature_attrs(fs_info, false);
 653         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 654         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 655         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 656 }
 657
 658 const char * const btrfs_feature_set_names[FEAT_MAX] = {
 659         [FEAT_COMPAT]    = "compat",
 660         [FEAT_COMPAT_RO] = "compat_ro",
 661         [FEAT_INCOMPAT]  = "incompat",
 662 };
 663
 664 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 665 {
 666         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 667         int len = 0;
 668         int i;
 669         char *str;
 670
 671         str = kmalloc(bufsize, GFP_KERNEL);
 672         if (!str)
 673                 return str;
 674
 675         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 676                 const char *name;
 677
 678                 if (!(flags & (1ULL << i)))
 679                         continue;
 680
 681                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 682                 len += snprintf(str + len, bufsize - len, "%s%s",
 683                                 len ? "," : "", name);
 684         }
 685
 686         return str;
 687 }
 688
 689 static void init_feature_attrs(void)
 690 {
 691         struct btrfs_feature_attr *fa;
 692         int set, i;
 693
 694         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 695                      ARRAY_SIZE(btrfs_feature_attrs));
 696         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 697                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 698
 699         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 700         memset(btrfs_unknown_feature_names, 0,
 701                sizeof(btrfs_unknown_feature_names));
 702
 703         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 704                 struct btrfs_feature_attr *sfa;
 705                 struct attribute *a = btrfs_supported_feature_attrs[i];
 706                 int bit;
 707                 sfa = attr_to_btrfs_feature_attr(a);
 708                 bit = ilog2(sfa->feature_bit);
 709                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 710
 711                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 712         }
 713
 714         for (set = 0; set < FEAT_MAX; set++) {
 715                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 716                         char *name = btrfs_unknown_feature_names[set][i];
 717                         fa = &btrfs_feature_attrs[set][i];
 718
 719                         if (fa->kobj_attr.attr.name)
 720                                 continue;
 721
 722                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 723                                  btrfs_feature_set_names[set], i);
 724
 725                         fa->kobj_attr.attr.name = name;
 726                         fa->kobj_attr.attr.mode = S_IRUGO;
 727                         fa->feature_set = set;
 728                         fa->feature_bit = 1ULL << i;
 729                 }
 730         }
 731 }
 732
 733 /* when one_device is NULL, it removes all device links */
 734
 735 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 736                 struct btrfs_device *one_device)
 737 {
 738         struct hd_struct *disk;
 739         struct kobject *disk_kobj;
 740
 741         if (!fs_devices->device_dir_kobj)
 742                 return -EINVAL;
 743
 744         if (one_device && one_device->bdev) {
 745                 disk = one_device->bdev->bd_part;
 746                 disk_kobj = &part_to_dev(disk)->kobj;
 747
 748                 sysfs_remove_link(fs_devices->device_dir_kobj,
 749                                                 disk_kobj->name);
 750         }
 751
 752         if (one_device)
 753                 return 0;
 754
 755         list_for_each_entry(one_device,
 756                         &fs_devices->devices, dev_list) {
 757                 if (!one_device->bdev)
 758                         continue;
 759                 disk = one_device->bdev->bd_part;
 760                 disk_kobj = &part_to_dev(disk)->kobj;
 761
 762                 sysfs_remove_link(fs_devices->device_dir_kobj,
 763                                                 disk_kobj->name);
 764         }
 765
 766         return 0;
 767 }
 768
 769 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 770 {
 771         if (!fs_devs->device_dir_kobj)
 772                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 773                                                 &fs_devs->fsid_kobj);
 774
 775         if (!fs_devs->device_dir_kobj)
 776                 return -ENOMEM;
 777
 778         return 0;
 779 }
 780
 781 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 782                                 struct btrfs_device *one_device)
 783 {
 784         int error = 0;
 785         struct btrfs_device *dev;
 786
 787         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 788                 struct hd_struct *disk;
 789                 struct kobject *disk_kobj;
 790
 791                 if (!dev->bdev)
 792                         continue;
 793
 794                 if (one_device && one_device != dev)
 795                         continue;
 796
 797                 disk = dev->bdev->bd_part;
 798                 disk_kobj = &part_to_dev(disk)->kobj;
 799
 800                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 801                                           disk_kobj, disk_kobj->name);
 802                 if (error)
 803                         break;
 804         }
 805
 806         return error;
 807 }
 808
 809 /* /sys/fs/btrfs/ entry */
 810 static struct kset *btrfs_kset;
 811
 812 /* /sys/kernel/debug/btrfs */
 813 static struct dentry *btrfs_debugfs_root_dentry;
 814
 815 /* Debugging tunables and exported data */
 816 u64 btrfs_debugfs_test;
 817
 818 /*
 819  * Can be called by the device discovery thread.
 820  * And parent can be specified for seed device
 821  */
 822 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 823                                 struct kobject *parent)
 824 {
 825         int error;
 826
 827         init_completion(&fs_devs->kobj_unregister);
 828         fs_devs->fsid_kobj.kset = btrfs_kset;
 829         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 830                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 831         if (error) {
 832                 kobject_put(&fs_devs->fsid_kobj);
 833                 return error;
 834         }
 835
 836         return 0;
 837 }
 838
 839 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 840 {
 841         int error;
 842         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 843         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 844
 845         btrfs_set_fs_info_ptr(fs_info);
 846
 847         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 848         if (error)
 849                 return error;
 850
 851         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 852         if (error) {
 853                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 854                 return error;
 855         }
 856
 857         error = sysfs_create_group(fsid_kobj,
 858                                    &btrfs_feature_attr_group);
 859         if (error)
 860                 goto failure;
 861
 862         error = addrm_unknown_feature_attrs(fs_info, true);
 863         if (error)
 864                 goto failure;
 865
 866         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 867                                                   fsid_kobj);
 868         if (!fs_info->space_info_kobj) {
 869                 error = -ENOMEM;
 870                 goto failure;
 871         }
 872
 873         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 874         if (error)
 875                 goto failure;
 876
 877         return 0;
 878 failure:
 879         btrfs_sysfs_remove_mounted(fs_info);
 880         return error;
 881 }
 882
 883
 884 /*
 885  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 886  * values in superblock. Call after any changes to incompat/compat_ro flags
 887  */
 888 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 889                 u64 bit, enum btrfs_feature_set set)
 890 {
 891         struct btrfs_fs_devices *fs_devs;
 892         struct kobject *fsid_kobj;
 893         u64 features;
 894         int ret;
 895
 896         if (!fs_info)
 897                 return;
 898
 899         features = get_features(fs_info, set);
 900         ASSERT(bit & supported_feature_masks[set]);
 901
 902         fs_devs = fs_info->fs_devices;
 903         fsid_kobj = &fs_devs->fsid_kobj;
 904
 905         if (!fsid_kobj->state_initialized)
 906                 return;
 907
 908         /*
 909          * FIXME: this is too heavy to update just one value, ideally we'd like
 910          * to use sysfs_update_group but some refactoring is needed first.
 911          */
 912         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 913         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 914 }
 915
 916 static void btrfs_init_debugfs(void)
 917 {
 918 #ifdef CONFIG_DEBUG_FS
 919         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 920
 921         /*
 922          * Example code, how to export data through debugfs.
 923          *
 924          * file:        /sys/kernel/debug/btrfs/test
 925          * contents of: btrfs_debugfs_test
 926          */
 927 #ifdef CONFIG_BTRFS_DEBUG
 928         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
 929                         &btrfs_debugfs_test);
 930 #endif
 931
 932 #endif
 933 }
 934
 935 int __init btrfs_init_sysfs(void)
 936 {
 937         int ret;
 938
 939         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 940         if (!btrfs_kset)
 941                 return -ENOMEM;
 942
 943         btrfs_init_debugfs();
 944
 945         init_feature_attrs();
 946         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 947         if (ret)
 948                 goto out2;
 949         ret = sysfs_merge_group(&btrfs_kset->kobj,
 950                                 &btrfs_static_feature_attr_group);
 951         if (ret)
 952                 goto out_remove_group;
 953
 954         return 0;
 955
 956 out_remove_group:
 957         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 958 out2:
 959         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 960         kset_unregister(btrfs_kset);
 961
 962         return ret;
 963 }
 964
 965 void __cold btrfs_exit_sysfs(void)
 966 {
 967         sysfs_unmerge_group(&btrfs_kset->kobj,
 968                             &btrfs_static_feature_attr_group);
 969         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 970         kset_unregister(btrfs_kset);
 971         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 972 }
 973