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 #include <linux/sched/mm.h>
  14
  15 #include "ctree.h"
  16 #include "disk-io.h"
  17 #include "transaction.h"
  18 #include "sysfs.h"
  19 #include "volumes.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_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(free_space_tree),
 209         NULL
 210 };
 211
 212 /*
 213  * Features which depend on feature bits and may differ between each fs.
 214  *
 215  * /sys/fs/btrfs/features lists all available features of this kernel while
 216  * /sys/fs/btrfs/UUID/features shows features of the fs which are enabled or
 217  * can be changed online.
 218  */
 219 static const struct attribute_group btrfs_feature_attr_group = {
 220         .name = "features",
 221         .is_visible = btrfs_feature_visible,
 222         .attrs = btrfs_supported_feature_attrs,
 223 };
 224
 225 static ssize_t rmdir_subvol_show(struct kobject *kobj,
 226                                  struct kobj_attribute *ka, char *buf)
 227 {
 228         return snprintf(buf, PAGE_SIZE, "0\n");
 229 }
 230 BTRFS_ATTR(static_feature, rmdir_subvol, rmdir_subvol_show);
 231
 232 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 233         BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 234         NULL
 235 };
 236
 237 /*
 238  * Features which only depend on kernel version.
 239  *
 240  * These are listed in /sys/fs/btrfs/features along with
 241  * btrfs_feature_attr_group
 242  */
 243 static const struct attribute_group btrfs_static_feature_attr_group = {
 244         .name = "features",
 245         .attrs = btrfs_supported_static_feature_attrs,
 246 };
 247
 248 static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
 249 {
 250         u64 val;
 251         if (lock)
 252                 spin_lock(lock);
 253         val = *value_ptr;
 254         if (lock)
 255                 spin_unlock(lock);
 256         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 257 }
 258
 259 static ssize_t global_rsv_size_show(struct kobject *kobj,
 260                                     struct kobj_attribute *ka, char *buf)
 261 {
 262         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 263         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 264         return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 265 }
 266 BTRFS_ATTR(allocation, global_rsv_size, global_rsv_size_show);
 267
 268 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
 269                                         struct kobj_attribute *a, char *buf)
 270 {
 271         struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
 272         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 273         return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 274 }
 275 BTRFS_ATTR(allocation, global_rsv_reserved, global_rsv_reserved_show);
 276
 277 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 278 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
 279
 280 static ssize_t raid_bytes_show(struct kobject *kobj,
 281                                struct kobj_attribute *attr, char *buf);
 282 BTRFS_ATTR(raid, total_bytes, raid_bytes_show);
 283 BTRFS_ATTR(raid, used_bytes, raid_bytes_show);
 284
 285 static ssize_t raid_bytes_show(struct kobject *kobj,
 286                                struct kobj_attribute *attr, char *buf)
 287
 288 {
 289         struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
 290         struct btrfs_block_group_cache *block_group;
 291         int index = btrfs_bg_flags_to_raid_index(to_raid_kobj(kobj)->flags);
 292         u64 val = 0;
 293
 294         down_read(&sinfo->groups_sem);
 295         list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
 296                 if (&attr->attr == BTRFS_ATTR_PTR(raid, total_bytes))
 297                         val += block_group->key.offset;
 298                 else
 299                         val += btrfs_block_group_used(&block_group->item);
 300         }
 301         up_read(&sinfo->groups_sem);
 302         return snprintf(buf, PAGE_SIZE, "%llu\n", val);
 303 }
 304
 305 static struct attribute *raid_attributes[] = {
 306         BTRFS_ATTR_PTR(raid, total_bytes),
 307         BTRFS_ATTR_PTR(raid, used_bytes),
 308         NULL
 309 };
 310
 311 static void release_raid_kobj(struct kobject *kobj)
 312 {
 313         kfree(to_raid_kobj(kobj));
 314 }
 315
 316 struct kobj_type btrfs_raid_ktype = {
 317         .sysfs_ops = &kobj_sysfs_ops,
 318         .release = release_raid_kobj,
 319         .default_attrs = raid_attributes,
 320 };
 321
 322 #define SPACE_INFO_ATTR(field)                                          \
 323 static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,      \
 324                                              struct kobj_attribute *a,  \
 325                                              char *buf)                 \
 326 {                                                                       \
 327         struct btrfs_space_info *sinfo = to_space_info(kobj);           \
 328         return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 329 }                                                                       \
 330 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 331
 332 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
 333                                                        struct kobj_attribute *a,
 334                                                        char *buf)
 335 {
 336         struct btrfs_space_info *sinfo = to_space_info(kobj);
 337         s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
 338         return snprintf(buf, PAGE_SIZE, "%lld\n", val);
 339 }
 340
 341 SPACE_INFO_ATTR(flags);
 342 SPACE_INFO_ATTR(total_bytes);
 343 SPACE_INFO_ATTR(bytes_used);
 344 SPACE_INFO_ATTR(bytes_pinned);
 345 SPACE_INFO_ATTR(bytes_reserved);
 346 SPACE_INFO_ATTR(bytes_may_use);
 347 SPACE_INFO_ATTR(bytes_readonly);
 348 SPACE_INFO_ATTR(disk_used);
 349 SPACE_INFO_ATTR(disk_total);
 350 BTRFS_ATTR(space_info, total_bytes_pinned,
 351            btrfs_space_info_show_total_bytes_pinned);
 352
 353 static struct attribute *space_info_attrs[] = {
 354         BTRFS_ATTR_PTR(space_info, flags),
 355         BTRFS_ATTR_PTR(space_info, total_bytes),
 356         BTRFS_ATTR_PTR(space_info, bytes_used),
 357         BTRFS_ATTR_PTR(space_info, bytes_pinned),
 358         BTRFS_ATTR_PTR(space_info, bytes_reserved),
 359         BTRFS_ATTR_PTR(space_info, bytes_may_use),
 360         BTRFS_ATTR_PTR(space_info, bytes_readonly),
 361         BTRFS_ATTR_PTR(space_info, disk_used),
 362         BTRFS_ATTR_PTR(space_info, disk_total),
 363         BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 364         NULL,
 365 };
 366
 367 static void space_info_release(struct kobject *kobj)
 368 {
 369         struct btrfs_space_info *sinfo = to_space_info(kobj);
 370         percpu_counter_destroy(&sinfo->total_bytes_pinned);
 371         kfree(sinfo);
 372 }
 373
 374 struct kobj_type space_info_ktype = {
 375         .sysfs_ops = &kobj_sysfs_ops,
 376         .release = space_info_release,
 377         .default_attrs = space_info_attrs,
 378 };
 379
 380 static const struct attribute *allocation_attrs[] = {
 381         BTRFS_ATTR_PTR(allocation, global_rsv_reserved),
 382         BTRFS_ATTR_PTR(allocation, global_rsv_size),
 383         NULL,
 384 };
 385
 386 static ssize_t btrfs_label_show(struct kobject *kobj,
 387                                 struct kobj_attribute *a, char *buf)
 388 {
 389         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 390         char *label = fs_info->super_copy->label;
 391         ssize_t ret;
 392
 393         spin_lock(&fs_info->super_lock);
 394         ret = snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 395         spin_unlock(&fs_info->super_lock);
 396
 397         return ret;
 398 }
 399
 400 static ssize_t btrfs_label_store(struct kobject *kobj,
 401                                  struct kobj_attribute *a,
 402                                  const char *buf, size_t len)
 403 {
 404         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 405         size_t p_len;
 406
 407         if (!fs_info)
 408                 return -EPERM;
 409
 410         if (sb_rdonly(fs_info->sb))
 411                 return -EROFS;
 412
 413         /*
 414          * p_len is the len until the first occurrence of either
 415          * '\n' or '\0'
 416          */
 417         p_len = strcspn(buf, "\n");
 418
 419         if (p_len >= BTRFS_LABEL_SIZE)
 420                 return -EINVAL;
 421
 422         spin_lock(&fs_info->super_lock);
 423         memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
 424         memcpy(fs_info->super_copy->label, buf, p_len);
 425         spin_unlock(&fs_info->super_lock);
 426
 427         /*
 428          * We don't want to do full transaction commit from inside sysfs
 429          */
 430         btrfs_set_pending(fs_info, COMMIT);
 431         wake_up_process(fs_info->transaction_kthread);
 432
 433         return len;
 434 }
 435 BTRFS_ATTR_RW(, label, btrfs_label_show, btrfs_label_store);
 436
 437 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 438                                 struct kobj_attribute *a, char *buf)
 439 {
 440         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 441
 442         return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 443 }
 444
 445 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
 446
 447 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 448                                 struct kobj_attribute *a, char *buf)
 449 {
 450         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 451
 452         return snprintf(buf, PAGE_SIZE, "%u\n",
 453                         fs_info->super_copy->sectorsize);
 454 }
 455
 456 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
 457
 458 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 459                                 struct kobj_attribute *a, char *buf)
 460 {
 461         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 462
 463         return snprintf(buf, PAGE_SIZE, "%u\n",
 464                         fs_info->super_copy->sectorsize);
 465 }
 466
 467 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
 468
 469 static ssize_t quota_override_show(struct kobject *kobj,
 470                                    struct kobj_attribute *a, char *buf)
 471 {
 472         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 473         int quota_override;
 474
 475         quota_override = test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 476         return snprintf(buf, PAGE_SIZE, "%d\n", quota_override);
 477 }
 478
 479 static ssize_t quota_override_store(struct kobject *kobj,
 480                                     struct kobj_attribute *a,
 481                                     const char *buf, size_t len)
 482 {
 483         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 484         unsigned long knob;
 485         int err;
 486
 487         if (!fs_info)
 488                 return -EPERM;
 489
 490         if (!capable(CAP_SYS_RESOURCE))
 491                 return -EPERM;
 492
 493         err = kstrtoul(buf, 10, &knob);
 494         if (err)
 495                 return err;
 496         if (knob > 1)
 497                 return -EINVAL;
 498
 499         if (knob)
 500                 set_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 501         else
 502                 clear_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags);
 503
 504         return len;
 505 }
 506
 507 BTRFS_ATTR_RW(, quota_override, quota_override_show, quota_override_store);
 508
 509 static const struct attribute *btrfs_attrs[] = {
 510         BTRFS_ATTR_PTR(, label),
 511         BTRFS_ATTR_PTR(, nodesize),
 512         BTRFS_ATTR_PTR(, sectorsize),
 513         BTRFS_ATTR_PTR(, clone_alignment),
 514         BTRFS_ATTR_PTR(, quota_override),
 515         NULL,
 516 };
 517
 518 static void btrfs_release_fsid_kobj(struct kobject *kobj)
 519 {
 520         struct btrfs_fs_devices *fs_devs = to_fs_devs(kobj);
 521
 522         memset(&fs_devs->fsid_kobj, 0, sizeof(struct kobject));
 523         complete(&fs_devs->kobj_unregister);
 524 }
 525
 526 static struct kobj_type btrfs_ktype = {
 527         .sysfs_ops      = &kobj_sysfs_ops,
 528         .release        = btrfs_release_fsid_kobj,
 529 };
 530
 531 static inline struct btrfs_fs_devices *to_fs_devs(struct kobject *kobj)
 532 {
 533         if (kobj->ktype != &btrfs_ktype)
 534                 return NULL;
 535         return container_of(kobj, struct btrfs_fs_devices, fsid_kobj);
 536 }
 537
 538 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 539 {
 540         if (kobj->ktype != &btrfs_ktype)
 541                 return NULL;
 542         return to_fs_devs(kobj)->fs_info;
 543 }
 544
 545 #define NUM_FEATURE_BITS 64
 546 #define BTRFS_FEATURE_NAME_MAX 13
 547 static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX];
 548 static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS];
 549
 550 static const u64 supported_feature_masks[FEAT_MAX] = {
 551         [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 552         [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 553         [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
 554 };
 555
 556 static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 557 {
 558         int set;
 559
 560         for (set = 0; set < FEAT_MAX; set++) {
 561                 int i;
 562                 struct attribute *attrs[2];
 563                 struct attribute_group agroup = {
 564                         .name = "features",
 565                         .attrs = attrs,
 566                 };
 567                 u64 features = get_features(fs_info, set);
 568                 features &= ~supported_feature_masks[set];
 569
 570                 if (!features)
 571                         continue;
 572
 573                 attrs[1] = NULL;
 574                 for (i = 0; i < NUM_FEATURE_BITS; i++) {
 575                         struct btrfs_feature_attr *fa;
 576
 577                         if (!(features & (1ULL << i)))
 578                                 continue;
 579
 580                         fa = &btrfs_feature_attrs[set][i];
 581                         attrs[0] = &fa->kobj_attr.attr;
 582                         if (add) {
 583                                 int ret;
 584                                 ret = sysfs_merge_group(&fs_info->fs_devices->fsid_kobj,
 585                                                         &agroup);
 586                                 if (ret)
 587                                         return ret;
 588                         } else
 589                                 sysfs_unmerge_group(&fs_info->fs_devices->fsid_kobj,
 590                                                     &agroup);
 591                 }
 592
 593         }
 594         return 0;
 595 }
 596
 597 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 598 {
 599         if (fs_devs->device_dir_kobj) {
 600                 kobject_del(fs_devs->device_dir_kobj);
 601                 kobject_put(fs_devs->device_dir_kobj);
 602                 fs_devs->device_dir_kobj = NULL;
 603         }
 604
 605         if (fs_devs->fsid_kobj.state_initialized) {
 606                 kobject_del(&fs_devs->fsid_kobj);
 607                 kobject_put(&fs_devs->fsid_kobj);
 608                 wait_for_completion(&fs_devs->kobj_unregister);
 609         }
 610 }
 611
 612 /* when fs_devs is NULL it will remove all fsid kobject */
 613 void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 614 {
 615         struct list_head *fs_uuids = btrfs_get_fs_uuids();
 616
 617         if (fs_devs) {
 618                 __btrfs_sysfs_remove_fsid(fs_devs);
 619                 return;
 620         }
 621
 622         list_for_each_entry(fs_devs, fs_uuids, fs_list) {
 623                 __btrfs_sysfs_remove_fsid(fs_devs);
 624         }
 625 }
 626
 627 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info)
 628 {
 629         btrfs_reset_fs_info_ptr(fs_info);
 630
 631         if (fs_info->space_info_kobj) {
 632                 sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
 633                 kobject_del(fs_info->space_info_kobj);
 634                 kobject_put(fs_info->space_info_kobj);
 635         }
 636         addrm_unknown_feature_attrs(fs_info, false);
 637         sysfs_remove_group(&fs_info->fs_devices->fsid_kobj, &btrfs_feature_attr_group);
 638         sysfs_remove_files(&fs_info->fs_devices->fsid_kobj, btrfs_attrs);
 639         btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL);
 640 }
 641
 642 const char * const btrfs_feature_set_names[FEAT_MAX] = {
 643         [FEAT_COMPAT]    = "compat",
 644         [FEAT_COMPAT_RO] = "compat_ro",
 645         [FEAT_INCOMPAT]  = "incompat",
 646 };
 647
 648 char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 649 {
 650         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
 651         int len = 0;
 652         int i;
 653         char *str;
 654
 655         str = kmalloc(bufsize, GFP_KERNEL);
 656         if (!str)
 657                 return str;
 658
 659         for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 660                 const char *name;
 661
 662                 if (!(flags & (1ULL << i)))
 663                         continue;
 664
 665                 name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
 666                 len += snprintf(str + len, bufsize - len, "%s%s",
 667                                 len ? "," : "", name);
 668         }
 669
 670         return str;
 671 }
 672
 673 static void init_feature_attrs(void)
 674 {
 675         struct btrfs_feature_attr *fa;
 676         int set, i;
 677
 678         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
 679                      ARRAY_SIZE(btrfs_feature_attrs));
 680         BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
 681                      ARRAY_SIZE(btrfs_feature_attrs[0]));
 682
 683         memset(btrfs_feature_attrs, 0, sizeof(btrfs_feature_attrs));
 684         memset(btrfs_unknown_feature_names, 0,
 685                sizeof(btrfs_unknown_feature_names));
 686
 687         for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
 688                 struct btrfs_feature_attr *sfa;
 689                 struct attribute *a = btrfs_supported_feature_attrs[i];
 690                 int bit;
 691                 sfa = attr_to_btrfs_feature_attr(a);
 692                 bit = ilog2(sfa->feature_bit);
 693                 fa = &btrfs_feature_attrs[sfa->feature_set][bit];
 694
 695                 fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
 696         }
 697
 698         for (set = 0; set < FEAT_MAX; set++) {
 699                 for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
 700                         char *name = btrfs_unknown_feature_names[set][i];
 701                         fa = &btrfs_feature_attrs[set][i];
 702
 703                         if (fa->kobj_attr.attr.name)
 704                                 continue;
 705
 706                         snprintf(name, BTRFS_FEATURE_NAME_MAX, "%s:%u",
 707                                  btrfs_feature_set_names[set], i);
 708
 709                         fa->kobj_attr.attr.name = name;
 710                         fa->kobj_attr.attr.mode = S_IRUGO;
 711                         fa->feature_set = set;
 712                         fa->feature_bit = 1ULL << i;
 713                 }
 714         }
 715 }
 716
 717 /* when one_device is NULL, it removes all device links */
 718
 719 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,
 720                 struct btrfs_device *one_device)
 721 {
 722         struct hd_struct *disk;
 723         struct kobject *disk_kobj;
 724
 725         if (!fs_devices->device_dir_kobj)
 726                 return -EINVAL;
 727
 728         if (one_device && one_device->bdev) {
 729                 disk = one_device->bdev->bd_part;
 730                 disk_kobj = &part_to_dev(disk)->kobj;
 731
 732                 sysfs_remove_link(fs_devices->device_dir_kobj,
 733                                                 disk_kobj->name);
 734         }
 735
 736         if (one_device)
 737                 return 0;
 738
 739         list_for_each_entry(one_device,
 740                         &fs_devices->devices, dev_list) {
 741                 if (!one_device->bdev)
 742                         continue;
 743                 disk = one_device->bdev->bd_part;
 744                 disk_kobj = &part_to_dev(disk)->kobj;
 745
 746                 sysfs_remove_link(fs_devices->device_dir_kobj,
 747                                                 disk_kobj->name);
 748         }
 749
 750         return 0;
 751 }
 752
 753 int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs)
 754 {
 755         if (!fs_devs->device_dir_kobj)
 756                 fs_devs->device_dir_kobj = kobject_create_and_add("devices",
 757                                                 &fs_devs->fsid_kobj);
 758
 759         if (!fs_devs->device_dir_kobj)
 760                 return -ENOMEM;
 761
 762         return 0;
 763 }
 764
 765 int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 766                                 struct btrfs_device *one_device)
 767 {
 768         int error = 0;
 769         struct btrfs_device *dev;
 770         unsigned int nofs_flag;
 771
 772         nofs_flag = memalloc_nofs_save();
 773         list_for_each_entry(dev, &fs_devices->devices, dev_list) {
 774                 struct hd_struct *disk;
 775                 struct kobject *disk_kobj;
 776
 777                 if (!dev->bdev)
 778                         continue;
 779
 780                 if (one_device && one_device != dev)
 781                         continue;
 782
 783                 disk = dev->bdev->bd_part;
 784                 disk_kobj = &part_to_dev(disk)->kobj;
 785
 786                 error = sysfs_create_link(fs_devices->device_dir_kobj,
 787                                           disk_kobj, disk_kobj->name);
 788                 if (error)
 789                         break;
 790         }
 791         memalloc_nofs_restore(nofs_flag);
 792
 793         return error;
 794 }
 795
 796 /* /sys/fs/btrfs/ entry */
 797 static struct kset *btrfs_kset;
 798
 799 /* /sys/kernel/debug/btrfs */
 800 static struct dentry *btrfs_debugfs_root_dentry;
 801
 802 /* Debugging tunables and exported data */
 803 u64 btrfs_debugfs_test;
 804
 805 /*
 806  * Can be called by the device discovery thread.
 807  * And parent can be specified for seed device
 808  */
 809 int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs,
 810                                 struct kobject *parent)
 811 {
 812         int error;
 813
 814         init_completion(&fs_devs->kobj_unregister);
 815         fs_devs->fsid_kobj.kset = btrfs_kset;
 816         error = kobject_init_and_add(&fs_devs->fsid_kobj,
 817                                 &btrfs_ktype, parent, "%pU", fs_devs->fsid);
 818         if (error) {
 819                 kobject_put(&fs_devs->fsid_kobj);
 820                 return error;
 821         }
 822
 823         return 0;
 824 }
 825
 826 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)
 827 {
 828         int error;
 829         struct btrfs_fs_devices *fs_devs = fs_info->fs_devices;
 830         struct kobject *fsid_kobj = &fs_devs->fsid_kobj;
 831
 832         btrfs_set_fs_info_ptr(fs_info);
 833
 834         error = btrfs_sysfs_add_device_link(fs_devs, NULL);
 835         if (error)
 836                 return error;
 837
 838         error = sysfs_create_files(fsid_kobj, btrfs_attrs);
 839         if (error) {
 840                 btrfs_sysfs_rm_device_link(fs_devs, NULL);
 841                 return error;
 842         }
 843
 844         error = sysfs_create_group(fsid_kobj,
 845                                    &btrfs_feature_attr_group);
 846         if (error)
 847                 goto failure;
 848
 849         error = addrm_unknown_feature_attrs(fs_info, true);
 850         if (error)
 851                 goto failure;
 852
 853         fs_info->space_info_kobj = kobject_create_and_add("allocation",
 854                                                   fsid_kobj);
 855         if (!fs_info->space_info_kobj) {
 856                 error = -ENOMEM;
 857                 goto failure;
 858         }
 859
 860         error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
 861         if (error)
 862                 goto failure;
 863
 864         return 0;
 865 failure:
 866         btrfs_sysfs_remove_mounted(fs_info);
 867         return error;
 868 }
 869
 870
 871 /*
 872  * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
 873  * values in superblock. Call after any changes to incompat/compat_ro flags
 874  */
 875 void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
 876                 u64 bit, enum btrfs_feature_set set)
 877 {
 878         struct btrfs_fs_devices *fs_devs;
 879         struct kobject *fsid_kobj;
 880         u64 features;
 881         int ret;
 882
 883         if (!fs_info)
 884                 return;
 885
 886         features = get_features(fs_info, set);
 887         ASSERT(bit & supported_feature_masks[set]);
 888
 889         fs_devs = fs_info->fs_devices;
 890         fsid_kobj = &fs_devs->fsid_kobj;
 891
 892         if (!fsid_kobj->state_initialized)
 893                 return;
 894
 895         /*
 896          * FIXME: this is too heavy to update just one value, ideally we'd like
 897          * to use sysfs_update_group but some refactoring is needed first.
 898          */
 899         sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
 900         ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
 901 }
 902
 903 static int btrfs_init_debugfs(void)
 904 {
 905 #ifdef CONFIG_DEBUG_FS
 906         btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
 907         if (!btrfs_debugfs_root_dentry)
 908                 return -ENOMEM;
 909
 910         /*
 911          * Example code, how to export data through debugfs.
 912          *
 913          * file:        /sys/kernel/debug/btrfs/test
 914          * contents of: btrfs_debugfs_test
 915          */
 916 #ifdef CONFIG_BTRFS_DEBUG
 917         debugfs_create_u64("test", S_IRUGO | S_IWUSR, btrfs_debugfs_root_dentry,
 918                         &btrfs_debugfs_test);
 919 #endif
 920
 921 #endif
 922         return 0;
 923 }
 924
 925 int __init btrfs_init_sysfs(void)
 926 {
 927         int ret;
 928
 929         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 930         if (!btrfs_kset)
 931                 return -ENOMEM;
 932
 933         ret = btrfs_init_debugfs();
 934         if (ret)
 935                 goto out1;
 936
 937         init_feature_attrs();
 938         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 939         if (ret)
 940                 goto out2;
 941         ret = sysfs_merge_group(&btrfs_kset->kobj,
 942                                 &btrfs_static_feature_attr_group);
 943         if (ret)
 944                 goto out_remove_group;
 945
 946         return 0;
 947
 948 out_remove_group:
 949         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 950 out2:
 951         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 952 out1:
 953         kset_unregister(btrfs_kset);
 954
 955         return ret;
 956 }
 957
 958 void __cold btrfs_exit_sysfs(void)
 959 {
 960         sysfs_unmerge_group(&btrfs_kset->kobj,
 961                             &btrfs_static_feature_attr_group);
 962         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 963         kset_unregister(btrfs_kset);
 964         debugfs_remove_recursive(btrfs_debugfs_root_dentry);
 965 }
 966